1 Flashcards
Technology helps us…
function
definition of technology
the practical application of knowledge especially in a particular area : engineering <medical></medical>
combining two technology definitions
capability of accomplishing a task
International Classification of Functioning, Disability and Health (ICF)
classification of health and health-
related domains
What is a key to health?
functioning
Indigenous Technology
Refers to the technological knowledge, skills, and resources transmitted or handed down from the past indigenous people to the present ones to meet their needs and wants by means of investigating, designing, developing, and evaluating products, processes, and systems with an intention of solving practical problems
Two broad categories of health technologies
- health care technologies
- assistive technologies
Two types of health care technologies
- medical technology
- information technology
medical technology
concerned with clinical treatment of disease
information technology
concerned with management of
health care delivery logistics, and analysis and administration of health care financial/clinical operations
a capability given by the practical application of
knowledge
a car’s fuel-saving technology
a manner of accomplishing a task especially using technical processes, methods, or knowledge
new technologies for information storage
the specialized aspects of a particular field of endeavor
educational technology
What are the three key areas of accelerating change in health-related technologies?
augmentation, treatments, diagnostics
What health-related functions is technology intended to advance?
- digital and communications
- neuro and cognitive
- health
- agricultural and natural manufacturing
- nano and material science
- energy
types of technologies in diagnostics
- medical tricorder
- biohacking
- labs on chips
- biometric sensors
medical tricorder
hypothetical handheld portable scanning device to be used by consumers to self-diagnose medical conditions within seconds and take basic vital measurements (e.g., blood pressure, temperature, blood flow)
augmentation
assists both less abled and fully able people to improve their senses, thought and biological functions
treatments
improve different kinds of illness, from genetic diseases, to organ replacements and anti-aging
dianostics
enabling doctors and citizens to learn about their medical state in real-time.
biohacking
techno-progressive cultural and intellectual movement which advocates for open access to genetic information and defends the potential of truly democratic technological development (e.g., nootropics/cybernetic devices for recording biometric data)
labs on chips
devices that integrates one or several laboratory functions on a single chip of only millimeters to a few square centimeters in size; deal with the handling of extremely small fluid volumes; safer platforms for chemical, radioactive or biological studies
biometric sensors
use of biometrics to telecommunications and telecommunications for remote biometric sensing (e.g., monitoring blood levels, infections, efficacy of vaccines)
organ printing
use of a combination of cells, engineering, material methods, suitable biochemical and physio-chemical factors to improve or replace biological functions
personalized medicine
branch of genomics where individual genomes are genotyped and analyzed using bioinformatics tools; may eventually lead to personalized medicine, where patients can take genotype specific drugs for medical treatments.
prenatal gene manipulation
the direct manipulation of an embryo/fetus genome using biotechnology
epigenetic therapy
phenomena whereby genetically identical cells express their genes differently resulting in different phenotypes in, for example, the formation of cancer originating from cancer stem cells.
anti-aging drugs
breakthroughs in tissue rejuvenation with stem cells, molecular repair, and organ replacement (such as artificial organs) might eventually enable humans to have indefinite lifespans through complete rejuvenation to a youthful condition
medical nanobots
studies how to make robots that emulate living biological organisms/functions mechanically or chemically; to enhance the human body’s capabilities or treat malfunctions with robots capable of re-programming and adapt to different conditions, always mimicking organic functions
enhanced organs
engineered replacement organs for humans that perform better than their natural counterparts. (e.g., artificial red blood cells and super-livers (via genetically engineered organs that overexpress key proteins; respirocytes, theoretical artificial red blood cells that carry oxygen 200x more efficiently than red blood cells).
machine-augmented cognition
effective use of information technology to augment human cognition using intelligence amplifying system of tools
biologically extended senses
the brain evolved to handle one construction of reality, yet now can overlay multiple local and remote experiences simultaneously, creating new cognitive perceptions (enhanced and produced artificially, which adapt and transform to address different kinds of stimuli for specific purposes).
bionic implants
microscopic technological structures that extract biometric information from an organism to analyze its performance and improve specific biological functions with assisted feedback
types of technologies in treatments
- organ printing
- personalized medicine
- prenatal gene manipulation
- epigenetic therapy
- anti-aging drugs
- medical nanobots
types of technologies in augmentation
- enhanced organs
- machine-augmented cognition
- biologically extended senses
- bionic implants
ELSI stands for…
Ethical
Legal
Social
Implications
ELSI research asks 2 kinds of questions:
What “is”? AND what “ought” to be?
What “is”?
To use scientific research
methods to collect data to test
hypotheses, evaluate programs, or
develop a theory of a phenomenon.
Examples:
* Do people receiving genetic test
results suffer emotional distress?
* Does persistence of posttest
distress correlate with pretest
temperament or traits?
What “ought” to be?
To use normative research methods to
determine what action (or policy or
practice) is ethically justified or most
appropriate.
Examples:
* If a study reveals an incidental
finding (e.g., misattributed
parentage), should an investigator
reveal that finding?
* If an incidental finding has health
implications for other family
members, should the law permit or
compel a clinician to attempt to
inform those family members,
perhaps over the objection of the
patient tested?
What is “ethics”?
branch of philosophy that is concerned with human conduct, more specifically the behaviour of individuals in society; rational justification for our moral judgments; what is morally right or wrong, just or unjust.
Four principles of health care ethics:
- autonomy
- non-maleficence
- beneficence
- justice
autonomy
respect a person’s freedom to choose what’s right for them
non-maleficence
do no harm
beneficence
all choices for a patient are made with the intent to do good
justice
treat and provide care fairly to all patients
information safety
protected all information and infrastructure
- infrastructure (e.g., computers, networks)
- confidential information (e.g., intellectual property, security info)
information privacy
protects information about individuals
(e.g., studen or patient records, SSNs)
autonomy privacy
ability of individuals to conduct activity without concern of or actual observation
(e.g., websites visited, research being conducted, and related data)
Why is a framework for identifying ethical issues of healthcare technologies needed?
The need for such a common framework was emphasized in 2010 when the Swedish Health and Medical Services Act (HMSA) introduced a requirement that all new health technologies of potential importance for human value and integrity should be assessed in terms of “individual as well as social ethical aspects”
What are the three main principles underlying the Swedish framework?
- human value principle
- need and solidarity principle
- cost-effectiveness principle
human value principle
all human beings are of equal value and have the same right independent of personal characteristics or function in society
determines primarily what factors that should not determine the priority setting (e.g., age, socioeconomic status, previous lifestyle), allows these factors to be taken into account if they affect the effectiveness of the treatment
need and solidarity principle
resources should be distributed according to need
meaning those with the most severe conditions, and those with the lowest quality of life; this applies even if it means that everyone cannot have their needs met in part or at all
cost-effectiveness principle
in choosing between different interventions, one needs to strive for a responsible relationship between cost and effects, measured in terms of improved health and quality of life
such patients with severe diseases and substantially impaired quality of life should take precedence over milder cases, even if this care involves “substantially” greater costs for a given health benefit
According to the Swedish framework, what are the four steps that should be followed in ethical reasoning about technology?
- effects on health
- compatibility with ethical norms
- structural factors with ethical implications
- long-term ethical consequences
effects on health
aspects related to the goal of health care and the urgency of the intervention are dealt with
compatibility with ethical norms
interventions’ compatibility with ethical norms are dealt with
structural factors with ethical implications
aspects, not directly of an ethical nature, but with possible implications for an equal access to the intervention are dealt with
long-term ethical consequences
long-term consequences of the intervention in itself of from side-effects are dealt with
Questions being asked in effects on health?
Q1 Health: How does the intervention influence the health of the patient in terms of quality of life and longevity? (HMSA and the needs and solidarity principle of the ethical platform)
Q2 Knowledge gaps: If there is insufficient scientific evidence to support the effect of the intervention, are there ethical and/or methodological obstacles to conducting further research to strengthen the evidence base? (HMSA’s demand for scientific support for health care treatments)
Q3 Severity of the condition: How serious is the condition which the intervention is intended to target? (HMSA and the needs and solidarity principle of the ethical platform)
Q4 Third party: How does the intervention affect the health of third parties? (HSMA)
Summary: Is the benefit-risk ratio of the intervention ethically acceptable?
Questions being asked compatibility with ethical norms?
Q5 Equality and justice: Is there a risk that access to the intervention violates the principle of human value or current legislation against discrimination? (HMSA, the human value principle of the ethical platform and the Swedish Discrimination Act)
Q6 Autonomy: Are the parents able to give informed consent or participate in relevant decisions concerning the intervention? (HMSA)
Q7 Privacy: How does the intervention affect the privacy of the parent and his/her relatives? (HMSA, and PDA)
Q8 Cost-effectiveness: Is there a reasonable balance between the cost of the intervention and its effectiveness? (HMSA and the cost effectiveness principle in the ethical platform)
Summary: Is the use of the intervention compatible with ethical norms?
Questions being asked in structural factors with ethical implications?
Q9 : Resources and organization: Are there resource and/or organizational limitations that can influence access to the intervention or can result in restricted availability of other procedures if the intervention is implemented? (HMSA and the ethical platform)
Q10: Professional values: Can values held by the relevant caring professions influence implementation of the intervention, thereby resulting in unequal access? (HMSA and the ethical platform)
Q11: Special interests: Are there special interests, which can influence implementation of the intervention, leading to unequal access? (HMSA and the needs and solidarity principle of the ethical platform, according to which health care should not be driven out of demand)
Summary: Is there reason to believe that an equal access to the intervention can be affected by the aspects in Q9-Q11?
Questions being asked in long-term ethical implications?
Q12: Long terms consequences: Can application of the intervention have ethical consequences in the long term?
mHealth and apps: ethical issues
no justice
Big data and predictive analytics: ethical issues
no autonomy
Robots: ethical issues
no justice
Nanotechnology: ethical issues
no justice
Brain implants: ethical issues
only beneficence
x-rays
quick, painless tests that produce images of the structures inside your body (especially bones)
Duration of x-rays
10-15 minutes
Imaging method of x-ray
ionizing radiation
X-rays are used to diagnose (7)
- bone fractures
- arthritis
- osteoporosis
- infections
- breast cancer
- swallowed items
- digestive tract problems
CT scans
use a series of x-rays to cross-sections of inside the body, including bones, blood vessels, and soft tissues
Duration of CT scans
10 to 15 minutes
CT scans are used to diagnose
- injuries from trauma
- bone fractures
- tumors and cancers
- vascular disease
- heart disease
- infections
- used to guide biopsies
MRI
use magnetic fields and radio waves to create detailed images of organs and tissues in the body
duration of MRI
45 minutes to 1 hour
MRI imaging method
magnetic waves
CT scan imaging method
ionizing radiation
MRI used to diagnose
- aneurysms
- Multiple Sclerosis (MS)
- stroke
- spinal cord disorders
- tumors
- blood vessel issues
- joint or tendon injuries
ultrasound
uses high frequency sound waves to produce images of organs and structures within the body
duration of ultrasound
30 minutes to 1 hour
imaging method of ultrasound
sound waves
ultrasound used to diagnose
- gallbladder disease
- breast lumps
- genital/prostate issues
- joint inflammation
- blood flow problems
- monitoring pregnancy
- used to guide biopsies
PET scan
use radioactive drugs (called tracers) and a scanning machine to show how your tissues and organs are functioning
duration of PET scan
1.5-2 hours
imaging method of PET scan
radiotracers
PET scan used to diagnose
- cancer
- heart disease
- coronary heart disease
- Alzheimer’s disease
- seizures
- epilepsy
- Parkinson’s disease
The dominant western view of the Medical Model is that:
- Illness is caused by bacteria, genes, virus or
accident. - Illnesses can be identified and classified into different
types such as diseases of the nervous system,
circulatory system etc. - The classification of disease is seen as objective
‘science’, - but it relies on doctors interpreting and labeling of symptoms
The medical model searches for…
physical explanations of causes (etiology) and
provides the basis for doctors ‘expert’ status
nosology
classification of illnesses
medicine classifies (_____) illness
taxonomizes
Michel Foucault (Foucauldian perspective)
critical studies of social institutions, most notably psychiatry, medicine, the human sciences, and the prison system, as well as for his work on the history of human sexuality
What book did Michel Foucault write?
The Birth of the Clinic: An Archaeology of Medical Perception
regard medical: who came up with it and what does it mean?
- Michel Foucault
- way of seeing (understanding)
What did Michel Foucault write in his book?
the birth of modern medicine was not a common sensical movement towards simply seeing what was already there (and therefore a science without
a philosophy), but rather a decisive shift in the structure of knowledge
What came out of The Birth of the Clinic?
a new philosophical way of granting meaning and
organizing certain objects (classifying; taxonomizing)
Elements of diagnosis (3):
- To distinguish among diseases or disorders
- To know thoroughly a disease or disorder; to
understand - To predict the course of disease or disorder
Diagnosis defintion
the art or act of identifying a disease
from its signs and symptoms
- the decision reached by diagnosis
Impetus for Innovation
- screening
- treatment
- legal
screening
Earlier diagnosis can pre-empt or prevent the onset of disease
(e.g., Pap tests; mammograms)
treatment
More accurate diagnosis can improve the choice of treatment and thereby lead to improved health outcomes
legal
Resolving disputes about who has legal and economic responsibilities (e.g., DNA paternity testing)
types of diagnostic technology
- Commonly used devices
- Laboratory tests
- Endoscopy
- Prenatal tests
- Diagnostic imaging
- Genetic testing
commonly used devices examples
- thermometers
- stethoscope
- sphygmomanometers (BP)
- otoscopes (examine ear canal/drum)
- ophthalmoscopes (retina, optic disk, blood vessels; glaucoma)
- electrocardiographs (electrical signals in heart)
- pulse oximeter (oxygen saturation)
- reflex (percussion) hammer (test deep tendon reflexes)
- penlight (assess pupil diameter)
laboratory tests
medical procedures that involve testing samples of blood, urine, or other tissues or substances
in the body
liquid portion of blood
plasma
When blood clots outside the
body, the blood cells and some of the
proteins become solid. The remaining
liquid is called _____
serum
serum is used in
chemical tests and in tests to find out how the immune system fights diseases
red blood cell count test measures
total number of RBCs per volume of whole blood
low values of red blood cell count test may indicate:
- blood loss
- hemorrhage
- bone marrow failure
- deficiencies in iron, folate, B6/12
- hemolysis
- certain cancers
high values in red blood cell count test may indicate
- high altitude
- congenital heart disease
- cor pulmonale
- polycythemia vera
- pulmonary fibrosis
- dehydration
WBC count test measures
total WBC component of whole blood
low values of WBC tests
- bone marrow failure
- presence of toxic substance
- autoimmune disease
- aplastic anemia
- liver or spleen disease
- radiation exposure
high values of WBC indicates
- infectious diseases (bacterial, viral, parasitic, protozoal)
- inflammatory disease
- leukemia
- severe emotional or physical stress
- tissue damage
diabetic person’s A1C test result
6.5% or above
diabetic person’s fasting blood sugar test result
126 mg/dL or above
diabetic person’s glucose tolerance test result
200 mg/dL or above
prediabetic person’s A1C test result
5.7-6.4%
prediabetic person’s fasting blood sugar test result
100 -125 mg/dL
prediabetic person’s glucose tolerance test result
140-199 mg/dL
normal person’s A1C test result
below 5.7%
normal person’s fasting blood sugar test result
99 mg/dL or below
normal person’s glucose tolerance test result
140 mg/dL or below
endoscopy
procedure that uses an instrument called an endoscope, or scope for short. Scopes have a tiny camera attached to a long, thin tube. It can be
moved through a body passageway or opening to see inside an organ. Sometimes scopes are used for surgery, such as for removing polyps from the colon.
Arthroscopy
joints
Bronchoscopy
lungs
Colonoscopy and sigmoidoscopy
large intestine
cystoscopy and ureteroscopy
urinary system
laparascopy
abdomen or pelvis
upper gastrointestinal endoscopy
esophagus and stomach
chorionic villus sampling (CVS)
invasive sampling of the placental tissue for further genetic analysis of OI. (used in 10th to 12th weeks of gestation)
cordocentesis
invasive sampling of umbilical cord blood for further OI genetic analysis (used on 22nd-24th weeks of gestation)
amniocentesis
invasive sampling of amniotic fluid for further OI genetic analysis (used from 15th to 20th weeks pf gestation)
non-invasive prenatal testing (NIPT)
NIPT uses fetal DNA from the mother’s bloodstream for prenatal testing of OI (used from 7th to 10th weeks of gestation)
ultrasound
allows to discover severe OI cases severe OI cases from 20th weeks of gestation non-invasively
CAT scan
A computerized axial tomography scan is an x-ray procedure that combines many x-ray images with the aid of a computer to generate cross-sectional views and, if needed, three-dimensional images of the internal organs and structures of the body
CAT scan is used to
define normal and abnormal structures in
the body and/or assist in procedures by helping to accurately
guide the placement of instruments or treatments
mammography false-positive rates
quite high (e.g., between 1% and 14%)
– Can put women through
unnecessary anxiety.
– Women who experience false-
positives developed a greater sense
of risk for breast cancer, and lost
confidence in their ability to do
breast self-examinations well
(Absetz et al., 2003; Long et al.,
2019).
– Can prompt breast biopsy: majority
are benign but nonetheless produce
significant distress.
motion artifacts in magnetic resonance imaging (MRI)
Motion artifacts: distortions to the MRI image caused by patient’s movement.
– Can render the scan useless.
– Up to 40% of scans have some degrees of motion artifacts, impairing
the quality of diagnosis 8%-17% of the time.
Genetic testing tests on…
Tests on blood, saliva, and other tissue to
find genetic disorders
Uses of genetic testing
– Finding possible genetic diseases in
unborn babies
– Finding out if people carry a gene for a
disease and might pass it on to their
children
– Screening embryos for disease
– Testing for genetic diseases in adults
before they cause symptoms
– Confirming a diagnosis in a person who
has disease symptoms
– Paternity testing
What is the Human Genome Project?
International scientific collaboration that sought to
understand the entire genetic blueprint of a human
being
What did the Human Genome Project reveal? And how?
there are probably about 20,500
genes (the basic units of heredity) in a human cell,
significantly fewer than estimates predicted
- mapped the location of these genes on the 23
pairs of human chromosomes, the structures
containing the genes in the cell’s nucleus
Aim of Human Genome Project
data derived from mapping and sequencing
the human genome will help scientists associate
specific human traits and inherited diseases with
particular genes at precise locations on the
chromosomes
The outcomes from family and twin
studies suggest that genetic factors
may account for as much as __ to ___
percent of body mass index (BMI)
variation in the general population
40 to 70
Comprehensive Study Uncovers Six Genetic
Variants Associated With Body Mass Index
Bethesda, Md., Sun. Dec. 14, 2008 —
- identified six new genetic variants
associated with BMI, or body mass index - the paper estimates that the 1 percent of people harboring the most obesity-causing variants will be an average of 10 pounds heavier than the 1 percent of individuals with the fewest variants, and 4 pounds heavier than a typical person
Miller, F.A., Ahern, C., Ogilvie, J., Giacomini, M. and Schwartz, L. (2005) Ruling in and ruling out: implications of molecular genetic diagnoses for disease classification, Social Science and Medicine, 61: 2536-45
“individual biographies are inserted into changing classification systems, and patients are ruled into or out of disease categories in unexpected ways”
Individual patients and their families
can get caught in the _____ of _____ change, which does what?
torque; nosologic
creating uncertainties about what disease they
‘‘have’’, and exposing them to uncertainties in clinical management and community practice
As predictive and pre-symptomatic tests increase, ________
so will the demand for monitoring (even from those who are told they have a low risk)
lead-time bias: what is it and when does it occur?
- length of time between the detection of a disease
(usually based on new, experimental criteria) and its usual clinical presentation and diagnosis (based on traditional criteria) - bias that occurs when two tests for a
disease are compared, and one test (the new, experimental one) diagnoses the disease earlier, but there is no effect on the outcome of the disease– it may appear that the test prolonged
survival, when in fact it only resulted in earlier diagnosis when compared to traditional methods. It is an important factor when evaluating the effectiveness of a specific test
length-time bias
form of selection bias, a statistical distortion
of results which can lead to incorrect conclusions about the data. Length time bias can occur when
the lengths of intervals are analyzed by selecting intervals that occupy randomly chosen points in time or space. This process favours longer intervals, thus skewing the data.
length-time bias and cancer cells
length time bias can affect data on screening tests
for cancer. Faster-growing tumours generally have a shorter asymptomatic phase than slower-growing tumours, and so are less likely to be detected. However, faster-growing tumours are also often associated with a poorer prognosis. Slower-growing tumours are hence likely to be over-represented in screening tests. This can mean screening tests are erroneously associated with improved survival, even if they have no actual effect on prognosis
over-diagnosis bias
Overestimation of survival duration among screen-detected cases due to the inclusion of pseudodisease - subclinical disease that would not become overt before the patient dies of other causes
Some researchers further divide pseudodisease into two categories:
- one in which the disease does not progress (Type I),
- the other in which the disease does progress – but so slowly that it never becomes clinically evident to the patient (Type II).
Availability heuristic
Diagnosis of current
patient biased by
experience with past
cases
Anchoring heuristic (premature closure)
Relying on initial diagnostic impression,
despite subsequent information to the contrary
Framing effects
Diagnostic decision-making unduly biased
by subtle cues and collateral information
Blind obedience
Placing undue reliance on test results or
“expert” opinion
A patient with crushing chest pain
was incorrectly treated for a myocardial infarction, despite indications that an aortic dissection was
present
availability heuristic
Repeated positive blood cultures
with Corynebacterium were dismissed as contaminants; the patient was eventually diagnosed with Corynebacterium endocarditis
Anchoring heuristic (premature closure)
A heroin-addicted patient with abdominal pain was treated for opiate withdrawal, but proved to have a bowel perforation
Framing effects
A false-negative rapid test
for Streptococcus pharyngitis resulted in a delay in diagnosis
Blind obedience
Technical feasibility and optimization
Ability to produce consistent results
Diagnostic accuracy
Sensitivity and specificity
Diagnostic thinking impact
Percentage of times clinicians’
subjective assessment of diagnostic
probabilities changed after the test
Therapeutic choice impact
Percentage of time therapy planned
before the test changed after the test
Patient outcome impact
Percentage of patients who improved
with diagnosis using the test compared
with those without diagnosis using the
test (e.g., survival, quality of life)
Societal impact
Cost-effectiveness analysis
How is a diagnostic test defined?
o providing information that impacts provider decisions regarding the prevention, diagnosis, treatment, and management of disease
o aid in identifying illness in a person who presents with symptoms by confirming or ruling out the presence of a specific disease or infection
What are sources of error (inaccuracy) in diagnostic testing?
processing, storage, transport, sampling, handling, preparation (in the preanalytical phase)
o may also arise when tests results are not appropriately communicated or used appropriately to inform health care decisions.
What are “in vitro diagnostics (IVD)”?
to test for disease or infection on samples that are removed from the body for analysis (fluids such as blood, urine, saliva, and sometimes, cerebrospinal fluid, or secretions and cells from the nose, throat, vagina, or an open wound).
What are the functions of IVD screening tests?
o Evaluate the likelihood of an individual developing a particular condition
o Routine and at-risk screening tests that may catch disease in its early stages
o Lifestyle changes can sometimes be made, or treatment done to minimize risk, or the impact of the condition should it develop
o Disease impacts can be minimized, and sometimes prevented, if caught early enough for treatment
What are the functions of IVD assessment tests?
o Tests that predict the effectiveness and potential side effects of specific treatments
o Tests that ensure ongoing safety and effectiveness of prescribed treatments or course of care
o Avoids suffering and wasted time from, and cost of, unproductive treatments
o Enables timely intervention to adjust or change treatment as necessary
What are the four categories of IVD diagnostic tests, and what is an example of a test in each category?
molecular, hematology, chemistry, microbiology
chemistry IVD diagostic tests
measure or detect specific substances (analyte) in the body to determine if they are present or present in “normal” amounts; if present in too high or too low amounts it can be an indication that something is wrong and may help identify a specific disease or condition
e.g., fluid samples – blood, urine, saliva
cholesterol, BUN, creatinine (kidney damage/disease)
hematology IVD diagnostic tests
focus on blood and the components of blood; white blood cells, red blood cells, and platelets created in the bone marrow present in a healthy human’s blood in predictable numbers, typically used to determine specific blood-related diseases or conditions
blood marrow is evaluated to diagnose blood cell cancers such as leukemia
CBC/hemoglobin (anemia), platelet count
microbiology IVD diagnostic tests
look for agents of infectious disease, including bacteria, viruses, parasites, mycobacteria, and fungi, or the body’s immune response (typically antibodies) to these microbes; may be found in patient samples from noses, throats, open wounds, blood, body fluids; Petri dishes, microscope; determines presence of disease or an antibody response to it
Rubella antibody, Hepatitis C antibody test, blood culture
molecular IVD diagnostic tests
analyze DNA, RNA, or the expression of proteins, look for abnormalities or variations in the genetic code, or identify the presence of specific genes in order to determine predisposition or presence of disease, presence of an infectious agent, or what particular treatment options are likely to be most effective
amplification, a process that produces many copies of the DNA in the fragment in order to allow detection and quantifying of the genes of interest
or probes
e.g., BRCA1, BRCA2, CF mutation
What is the difference between the accuracy and precision of a diagnostic test?
o accuracy: how close reported test results are to the “true” value
o precision: how close test results are to each other when they are repeated multiple times on the same sample (precise test is one that consistently and reliably produces the same result)
What is the difference between the sensitivity and specificity of a diagnostic test?
o sensitivity: measures the probability that a person has the disease or condition suspected by the health care provider (
o specificity: measures the probability that a person does not have the suspected disease or condition (test is 95% specific, 100 people tested, 5% false-positive rate)
types of reproductive technologies
- Assisted reproductive technology (ART)
- Contraception
- Emerging technologies
What type of reproductive technology is used to treat infertility?
ART
includes all fertility treatments in which either eggs or embryos are handled.
ART
the only application of RT that is used routinely is…
ART
Examples of ART (4):
- Artificial insemination
- In Vitro Fertilization and Embryo Transfer (IVF-ET)
- Surrogacy
- Mitochondrial Replacement Therapy (MRT)
laparascopy
direct visualization of the peritoneal cavity, ovaries, outside of the tubes and uterus by using a laparoscopy. The laparoscopy is an instrument
somewhat like a miniature telescope with a fiber optic system which brings light
into the abdomen. It is about as big around as a fountain pen and twice as long.
cryopreservation
Process where cells (embryos, eggs, sperm) or whole tissues are preserved by cooling to low sub-zero temperatures, such as 77 K or −196 °C. At these low temperatures, any biological activity, including the biochemical reactions that would lead to cell death, is effectively stopped.
In Vivo Fertilization:
Fertilization of a ripe egg within the uterus of
a fertile donor female, rather than in an
artificial medium, for subsequent nonsurgical
transfer to an infertile recipient.
In vitro fertilization
Process by which egg cells are fertilized by
sperm outside of the uterus.
The first “test tube baby” was born in 1978
Four stages in IVF:
- superovulation
- egg retrieval
- fertilization/insemination
- embryo transfer
IVF is a treatment for what? (2)
A treatment for male infertility.
May also be used where eggs cannot
easily be penetrated by sperm.
Intracytoplasmic sperm injection
(ICSI).
– Procedure in which a single
sperm is injected directly into an
egg
Why is artificial insemination needed?
- Infertility:
– The woman’s partner produces too few motile sperm. - The woman’s partner carries a genetic disorder.
- The woman has no male partner
Semen preparation: how does it work?
Semen preparation techniques separate motile sperm that are morphologically normal (normal appearance) from seminal plasma (the fluid portion of the semen in which the spermatozoa are
suspended) and foreign material.
– It is known that white blood cells, bacteria and dead spermatozoa produce oxygen radicals that negatively influence the ability of normal spermatozoa to fertilize the egg.
A sperm wash solution containing antibiotics and protein supplements is added to the ejaculate. After repeated centrifugation, the seminal fluid is eliminated from the sample and the sperm cells are concentrated for insemination. This procedure takes 20 to 40 minutes.
Intracytoplasmic sperm injection (ICSI) is used for what?
An assisted reproductive technology (ART) used to treat certain infertility problems, such as sperm-related infertility. ICSI is used to enhance the fertilization phase of in vitro fertilization (IVF) by injecting a single sperm into a mature egg.
Types of artificial insemination (AI) (4):
- intreuterine insemination
- intracervical insemination
- intratubal insemination
- intravaginal insemination
Process of Intracytoplasmic sperm injection (ICSI)
Process:
– Sperm is placed into the reproductive tract of a female
for the purpose of impregnating the female by using means other than sexual intercourse.
– Freshly ejaculated sperm, or sperm which has been frozen and thawed, is placed in the cervix
(intracervical insemination, ICI; more popular
method) or in the female’s uterus (intrauterine
insemination, IUI) by artificial means.
* The woman is the gestational and genetic mother of the child produced.
* The sperm donor is the genetic or biological father of the child.
* There may be a slight increased likelihood of multiple births rather than singleton babies if drugs are used by the woman for a stimulated cycle.
Why are IVF-related forms of ART rarely used?
These procedures have higher costs and risks
related to laparoscopy. And they don’t provide as much useful information about embryo development as IVF does
First step of IVF related forms of ART:
superovulation
- uses medicines to stimulate the ovaries to produce multiple eggs. Medicines that may be used are letrozole or gonadotropins, such as a follicle-stimulating hormone (FSH).
What is GIFT?
- sperm and eggs are placed in a fallopian tube to allow fertilization in the natural site
- the woman must have at least one normal, open fallopian tube
What does GIFT stand for?
gamete intrafallopian transfer
Three step procedure of GIFT:
- removing the eggs
- the eggs are placed into a thin flexible tube (catheter) along with the sperm to be used
- the gamete (both eggs and sperm) are then injected into the fallopian tubes using a surgical procedure called laparoscopy (the doctor will use general anesthesia)
pregnancy rates with GIFT
- 37% for women age 38 and younger
- 24% for women age 39 and older
What does ZIFT stand for?
zygote intrafallopian transfer
Three steps of ZIFT
- Eggs are stimulated and collected using IVF
methods. - Then the eggs are mixed with sperm in the
lab. - Fertilized eggs (zygotes) are then returned to
the fallopian tubes with laparascopic surgery.
From there, they will be carried into the
uterus. The goal is for the zygote to implant in
the uterus and develop into a fetus
How many surgical procedures are required with ZIFT?
two
- when the eggs are retrieved
- when they are implanted into the fallopian tube
Which is more successful: GIFT or ZIFT?
ZIFT (fertilization has already taken place)
Why does ZIFT have an advantage over IVF?
fewer eggs are being used; lessening risk of multiple birth
Why are fewer GIFT procedures being done compared to IVF?
– IVF does not require general anesthesia or
laparoscopic intervention.
– Currently, GIFT patients are mainly those who
may require diagnostic laparoscopy or
laparoscopy for treatment of endometriosis, in
which case procedures are combined as a cost
saving measure
Mitochondrial Replacement Therapy (MRT)
new form of reproductive in vitro fertilization (IVF) which works on the principle of replacing a women’s abnormal mitochondrial DNA (mt-DNA) with the donor’s healthy one
Chemical energy produced by the
mitochondria is stored in a small molecule
called
adenosine triphosphate (ATP)
Three different types of artificial cloning:
- gene cloning
- reproductive cloning
- therapeutic cloning
gene cloning
produces copies of genes or segments of DNA
reproductive cloning
produces copies of whole animals
therapeutic cloning
produces embryonic stem cells for experiments aimed at creating tissues to replace injured or diseased tissues
How does “somatic cell nuclear transfer” (SCNT) work?
scientists transfer genetic material from the
nucleus of a donor adult cell to an egg whose nucleus, and thus its genetic material, has been removed
In reproductive cloning, once the cloned embryo
reaches a suitable stage…
it is transferred to the uterus of a female host where it continues to develop until
birth
Dolly or any other animal created using nuclear
transfer technology truly an identical clone
of the donor animal?
No.
Why is human cloning fiction/not feasible? (3)
– There currently is no solid scientific evidence that anyone has cloned human embryos.
– From a technical perspective, cloning humans and other primates is more difficult than in other mammals.
– One reason is that two proteins essential to cell division, known as spindle
proteins, are located very close to the chromosomes in primate eggs. Consequently, removal of the egg’s nucleus to make room for the donor nucleus also removes the spindle proteins, interfering with cell division
Why is Dolly’s success remarkable?
proved that the genetic material from a
specialized adult cell, such as an udder cell
programmed to express only those genes
needed by udder cells, could be reprogrammed
to generate an entire new organism.
Preimplantation Genetic Diagnosis (PGD)
The genetic profiling of embryos prior to implantation, and sometimes even of oocytes prior to fertilization.
Surrogacy (what is it and the two types)
A method of reproduction whereby a woman agrees to become pregnant an deliver a child for a
contracted party.
She may be the child’s genetic mother (the more traditional form of surrogacy) Or she may act as a gestational carrier, to carry the pregnancy to delivery after having been implanted with an embryo.
Testicular Sperm Extraction (TESE)
The process of removing a small
portion of tissue from the
testicle under local anesthesia
to extract viable sperm cells.
– for the purpose of
intracytoplasmic sperm
injection (ICSI)
TESE is recommended for:
men who are unable to
produce sperm by
ejaculation as a result of
primary testicular failure,
congenital absence of the
vas deferens or non-
reconstructed vasectomy.
Contraception (physical methods)
- Barrier (condom, sponge, cervical
cap) - Hormonal (“the pill”)
- Emergency (“morning after pill”)
- Intrauterine (IUD)
- Induced abortion
- Sterilization (tubal ligation and
vasectomy)
Emerging contraceptive technologies (females)
- Spermicides
- Spray-on contraceptives
Emerging contraceptive technologies (males)
- Oral contraceptive
- Spermicides
- Vas-occlusive contraception
- Heat-based contraception (testicles)
Other Emerging Technologies (4)
- artificial wombs
- germinal choice technology
- in vitro parthenogenesis
- reprogenetics
germinal choice technology
allows parents to influence the genetic constitution of their children
in vitro parthenogenesis
an asexual form of reproduction found in females where growth and development of embryos or seeds occurs without fertilization by a male
reprogenetics
the merging of reproductive and
genetic technologies expected to happen in the near future as techniques like Germinal Choice technology become more available and more powerful
What % of ART candidates use the service?
5%
Why is ART used by such a low % of candidates?
cost or lack of accessibility in certain geographic areas
Controversial/ethical issues with RT
- assumptions behind existing systems of
sexual and reproductive morality. - issues of human enhancement (application
to reproductively healthy people.
ELSI issues with RT
What to do with leftover frozen embryos?
Compensation for egg or embryo donation?
Donor sperm for single women or gay couples?
Number of embryos transferred into the uterus leading to high order multiple pregnancies with the possible need for selective reduction?
Genetic counseling and preimplantation diagnosis?
Is there a higher risk of birth defects following ART compared with non-ART infants?
Yes; 32% increased risk
The Assisted Human Reproduction Act (2004) prohibits three things:
- The AHR Act prohibits human cloning and regulates the use of human embryos in research.
- The Act prohibits payment for surrogacy, and for gamete, gene, or cell donations.
- The Act prohibits pre-determining the sex of an embryo using pre-implantation genetic diagnosis (PGD), except to prevent a sex-linked disease or genetic condition. Therefore, for example, using PGD for “family balancing” is prohibited in Canada
The Assisted Human Reproduction Act (2004) allows three things:
– Intrauterine insemination (IUI)
– In vitro fertilization (IVF) and intra cytoplasmic sperm injection (ICSI)
– Obtaining or importing sperm and eggs for reproductive purposes, or in vitro
embryos for any purpose
What are the two main categories of artificial insemination?
o using the semen of the husband or designated partner (AIH)
o employing semen of a third party, or donor insemination (DI)
When is using the semen of the husband or designated partner (AIH) recommended? (4)
recommended when the male partner is unable to ejaculate within the vagina
when the sperm displays deficiencies in numbers of sperm or in their ability to move
when male partner has hypospadias (a penile abnormality in which the opening of the urethra is located a distance from the tip of the glans penis, causes the ejaculate to be deposited at the periphery of the vagina even when the penis is well within)
when male partner has retrograde ejaculation (caused by a complication of prostatic surgery resulting in the formation of a channel that causes the ejaculate to be directed away from the penis and retrograded into the bladder)
When is employing semen of a third party, or donor insemination (DI) recommended?
when male partner suffers from azoospermia (absence of spermatozoa)
quality of specimen is poor/deficiencies in semen
Huntington’s disease, Tay-Sachs disease or hemophilia
What ethical concerns distinguish these two categories (semen donor vs. partner)?
(with donor) both partners are usually required to review and sign a detailed informed-consent form; awareness of the importance of careful counseling and the use of appropriate permission forms; it is important to maintain confidential donor records, including all of the information on the screening procedures, so that it is available in the future in case it is needed for medical reasons
What is the process known as capacitation?
o spermatozoon is exposed to the environment of the female reproductive tract for a period of time before it acquires the ability to penetrate the layers surrounding the recently ovulated oocyte
o takes between one and two hours in the human
What techniques are used to enhance ovulation and fertilization in in vitro fertilization and embryo transfer (IVF-ET)?
o donor insemination is sometimes used in IVF when there is failure of fertilization using the male partner’s specimen
o analogues of the gonadotropinreleasing hormone are now used to prevent the patient from ovulating before the oocytes could be obtained; they block the release of the patient’s pituitary gonadotropins, and the ovaries can be brought under the complete control of exogenously administered hormones.
What procedures are used to screen semen donors? (3)
o serologic tests: syphilis and serum hepatitis B antigen (initially and after 6 months)
o genitalia cultured for gonorrhea and chlamydia
o screening for AIDS virus antibodies is (after 6 months)
How reliable is cryopreservation of spermatozoa and oocytes?
o success rate of cryopreservation is unpredictable
o lower pregnancy rate
Why is IVF treatment considered to be both physically and emotionally demanding?
o several visits for hormone determinations and ultrasound are required
o ovum recovery usually has complications
o ovarian infection may occur
In IVF, why is it that normally no more than two fertilized oocytes are transferred in women under age thirty-five and three in the older group?
o greatly increased possibility of multiple pregnancy
o triplets or more greatly increase the possibility of fetal loss
What is micromanipulation and when is it used?
o manipulation of gametes and pre-embryos under magnification
o used to insert a spermatozoon mechanically through the zona pellucida directly into the oocyte itself (intracytoplasmic sperm insertion – ICSI)
o used for males with a congenitally obstructed vas deferens; sperm recovered from epididymis
o used to determine whether the embryo is genetically normal by removing the second polar body for chromosome analysis
For what kinds of infertility patients is GIFT used and not used?
o used for: couples with unexplained infertility and women with extratubal disease (pelvic adhesions or endometriosis)
o not used for: those with damaged or absent fallopian tubes
What kinds of surrogacy are there? (2)
o 1. surrogate provides the gestational, but not the genetic component (pre-embryo transferred to woman other than the woman providing the oocytes)
o 2. surrogate provides the genetic component (husband’s spermatozoa are used to inseminate a woman other than his wife; surrogate mother carries the gestation to term)
o used when ovaries are present, but not uterus
Why is cytoplasmic transfer between human oocytes performed and what are the risks?
o cytoplasmic transfer is used to improve oocyte quality
o ovarian infection could occur following ovum retrieval, which could result in permanent sterility
o children born as a result of this technique have now exhibited traces of mitochondrial DNA from the donor egg – may result in untoward consequences in the future and, defects transmitted might be heritable and therefore could be observed in the next generation
Regenerative Medicine
Engineering the properties of tissues and cells so that they might be introduced into a patient in order to regenerate damaged or non-functional tissue, such as bone, brain, cartilage, and blood
cells.
Examples of RM
Can involve combining biological tissue with synthetic materials.
– E.g., creating new tissue for treatment of ulcers and skin
lesions associated with diabetes, and for serious burns.
– E.g., repair of bone fractures.
CRISPR stands for
Clustered
Regularly
Interspaced
Short
Palindromic
Repeats
What is CRISPR?
gene editing tool that acts as a precise pair of molecular scissors that can cut a target DNA sequence, directed by a customizable guide
Palindromic sequence
A palindromic sequence of nucleotides (which are labeled A, T, C, or G) occurs when complementary strands of DNA read the same in both directions
Some bacteria possess an immune system, based on the CRISPR-Cas mechanism, that confers adaptive immunity against viruses; when the target DNA is found…
- When the target DNA is found, Cas9 – one of the enzymes produced by the CRISPR system – binds to the DNA and cuts it, shutting the targeted gene off.
- Using modified versions of Cas9, researchers can activate gene expression instead of cutting the DNA.
Two types of stem cells
- adult stem cells
- embryonic stem cells
Compared with embryonic stem cells, adult
stem cells have a
more limited ability to give
rise to various cells of the body
Where are adult stem cells located?
- present in many
adult tissues, such as bone marrow or fat
pluripotent stem cells
they can divide into more stem cells or can
become any type of cell in the body
embryonic stem cells are ____ stem cells
pluripotent
embryonic stem cells
– come from embryos that are 3 to 5 days old
* at this stage, an embryo is called a
blastocyst and has about 150 cells
– this versatility allows embryonic stem cells to
be used to regenerate or repair diseased
tissue and organs
adult stem cells are designed to:
reproduce to maintain and repair the specific tissue or organ in which they are found
autologous
isolated and extracted from oneself
allogenic
isolated and extracted from other people
bone marrow contains at least two types of stem cells:
- hematopoietic
- stromal
hematopoietic stem cells
form all the types of blood cells in the
body
stromal stem cells
a mixed cell population that generates bone, cartilage, fat, and fibrous connective tissue.
embryonic stem cells come from
donated ‘spare’ embryos from IVF programs.
embryonic stem cells have the unique capacity to (3)
- To renew themselves indefinitely.
- To become specialized cells.
- Totipotent
– Early stage of fetal development (up to 8 cells).
totipotent
capable of developing into a complete
organism or differentiating into any of its cells or tissues (including extra-embryonic
tissues – placenta and umbilical cord).
pluripotent
capable of differentiating into one of many cell types
blastocyte stage of ESC + the three parts of blastocyte
A preimplantation embryo of
30-150 cells.
The blastocyst consists of a sphere made up of an outer layer of cells (the
trophectoderm), a fluid-filled cavity (the blastocoel), and a cluster of cells on the interior
(the inner cell mass)
Gastrulation of a diploblast:
The formation of germ layers from a (1) blastula to a (2) gastrula. Some of the ectoderm cells (orange) move inward forming the endoderm (red).
human embryonic germ cells come from:
medically terminated pregnancies
Are human embryonic germ cells known to be pluripotent?
No.
Mesenchyme (mesenchymal cells):
Cells of mesodermal origin that are capable of
developing into connective tissues, blood, and
lymphatic and blood vessels
Have scientists who studied human embryonic stem cells agreed on a standard of tests that measure the cells fundamental properties?
No.
What laboratory tests are used to identify embryonic stem cells? (2)
- Growing and sub-culturing the stem cells for many months
- Determining the presence of surface markers that are found only on undifferentiated cells
- Examining the chromosomes under a
microscope. - Testing whether the human embryonic stem
cells are pluripotent
Growing and sub-culturing the stem cells for many months ensures that…
the cells are capable of long-term self-renewal
Examples of determining the presence of surface markers that are found only on undifferentiated cells
test for the presence of a protein called Oct-4, which helps turn genes on and off at the right
time
Examining the chromosomes under a
microscope
This is a method to assess whether
the chromosomes are damaged or if the number
of chromosomes has changed. It does not detect
genetic mutations in the cells.
Testing whether the human embryonic stem
cells are pluripotent (three ways)
a. allowing the cells to differentiate
spontaneously in cell culture;
b. manipulating the cells so they will
differentiate to form specific cell types; or
c. injecting the cells into an immunosuppressed
mouse to test for the formation of a benign
tumor called a teratoma. Teratomas typically
contain a mixture of many differentiated or
partly differentiated cell types—an indication
that the embryonic stem cells are capable of
differentiating into multiple cell types.
California Stem Cell Research and Cures Act
- Introduced in 2004 as “Proposition 71”
- Campaign relied heavily on the support of Christopher Reeve
- Established an institute for regenerative medicine; $300
million
Applications of Stem Cell Research (4)
- Potential to cure “incurable” conditions, such as Parkinson’s disease.
- Repair damaged organs (e.g., heart and spinal cord).
- Testing drug toxicity (based on human models instead of animal models) (an important new advance)
- Immune system therapy in Multiple Sclerosis (MS)
Parkinson’s Disease (PD)
Caused by a progressive degeneration and loss of dopamine (DA)-producing neurons, which leads to tremor, rigidity, and hypokinesia (abnormally decreased mobility)
It is thought that ____ may be the first disease to be amenable to treatment using stem cell transplantation because…
PD; the knowledge of the specific cell type (DA neurons) needed to relieve the symptoms of the disease, several laboratories have been successful in developing methods to induce embryonic stem cells to differentiate into cells with many of the functions of DA neurons
The success of stem cell therapies requires technologies to ensure that stem cells (7)
- Proliferate extensively and generate sufficient quantities of tissue.
- Differentiate into the desired cell
type(s). - Survive in the recipient after transplant.
- Integrate into the surrounding tissue after transplant.
- Function appropriately for the duration of the recipient’s life.
- Avoid harming the recipient in any way.
- Avoid the problem of immune rejection.
Ethical Debate of embryonic stem cell research
- Harvesting embryonic stem cells destroys the
blastocyst - “This is murder”
- Embryonic stem cell research requires human
cells. - Could create a commercial market for human cells.
- “This devalues life”
Governing ES cell research: which country has the least restrictions on ES research and which has the most?
- most: UK
- least: Germany
Law governing ES research in Canada is called
Assisted Human Reproduction and Related
Research Act was passed in March 2004
Is the use of existing ES cell lines allowed in Canada?
Yes (unrestricted)
Is the use of excess embryos from IVF
clinics allowed?
Yes (controlled)
- blastocyst must be destroyed
after 14 days of development
- written consent from donors
required
- no sale of human cells
donor
- must be at least 18 yrs old
Is the creation of embryos by IVF for
ES cell research allowed in Canada?
No.
Is therapeutic cloning allowed in Canada?
No.
Describe 3 main uses for tissue engineering?
maintain, restore, or improve the function of damaged tissues
What is the difference between tissue engineering and regenerative medicine?
o tissue engineering is used to treat more severe diseases that cannot be treated with regular pharmaceuticals (e.g., Alzheimer’s, Parkinson’s, osteoarthritis) or diseases at advanced stages
What is meant by “autologous tissues”?
o tissue taken from another location of the individual’s body
What is meant by The Triad of Tissue Engineering?
o the combination of three pillars: cells, signals, and scaffolds
cells: autologous, heterologous, differentiated, stem cell
signals: growth factors, small molecules, mechanical forces,
biomaterials/scaffolds: natural, synthetic, hydrogels, meshes
o current advances in tissue engineering involve development in all elements of the triad
What does ECM stand for and why is it important?
o ECM: extracellular matrix
o it is a natural scaffold that allows cell attachment, proliferation, and differentiation
o important because it is involved in a method of scaffolding: the decellularization of the ECM from either allogeneic or xenogeneic tissues; when seeded with the proper cells, it can produce an autologous construct without the need for extracting tissues from the patient him/herself
What is “scaffolding” and what are some technical challenges with these procedures?
o scaffolding: support structures designed to facilitate cellular growth and proliferation upon implantation into the patient
o challenges:
choosing scaffold biomaterials: scaffolds must respond to both the structural and functional requirements of the body (must be biocompatible and should be able to communicate with the ECM while at the same time providing the needed mechanical support)
use of a pre-made porous scaffold: post-fabrication cell seeding is both time consuming and not efficient
encapsulating the cells during scaffold formation: load-bearing functions
decellularization of the ECM: inhomogeneous distribution of the seeded cells and the difficulty of removing all immune-provoking material
What is meant by “allogeneic” and “xenogeneic” cell sources and why are they used?
o allogeneic: cells that are genetically dissimilar and hence immunologically incompatible, although from individuals from the same species
o xenogeneic: cells belonging to individuals of different species
o used to overcome the shortage of autologous cell availability
What is most often used type of stem cell in tissue engineering?
o autologous cells
o do not evoke immune response; eliminate need for immunosuppressants and their side effects
What is meant by “smart biomaterials” in tissue engineering?
o smart biomaterials: capable of directing cell functions and/or enhancing cellular performance
o designed to interact with biological systems for a wide range of biomedical applications; from the delivery of bioactive molecules and cell adhesion mediators to cellular functioning for the engineering of functional tissues to treat diseases
What are the most important signals sensed by cells?
the ones that involve oxygen levels, mechanical stimulation, growth factors, ECM molecules, and other small molecules
What are some of the most commonly used growth factors in tissue engineering and what processes are they used for?
o in general, they play fundamental roles in bone repair and bone formation
o most commonly used type: bone marrow stromal cells (BMSCs)
able to differentiate toward the osteogenic lineage
o bone morphogenetic proteins (BMPs)
shown to induce bone formation especially BMP-2 and BMP-7
o TGF-β [121], VEGF [122], fibroblastic growth factor (FGF), insulin-like growth factor (IGF), and platelet-derived growth factor (PDGF)
involved in bone repair and bone formation
Name 3 areas of new applications for tissue engineering
o development of extracorporeal life support units
o in vitro disease models
o tissues for drug screening
o smart diagnosis
o personalized medicine
What is the aim of using tissue engineering for disease modelling?
o to be able to control and ideally to cure many diseases that are still incurable
o mimic the natural properties available in vivo such as architecture, environment, growth factors, and biomechanics; the tissue is just an intermediate step toward the development of the actual treatment
How has tissue engineering helped to advance the field of personalized medicine?
o drug testing: engineered tissue is used to make a 3D model of a patient’s organ, to test the efficacy of different drugs on different patients
o tailoring the tissue construct itself to fit the needs of a specific patient: allows the cells’ survival by making it compatible with the cells’ microenvironment and with the host tissue’s mechanical, physical, and chemical properties
Describe 2 current challenges in tissue engineering.
o deciding the source of cells (autologous, allogenic, xenogeneic) to seed in the scaffold is numerous and challenging
o choice of scaffold biomaterials
must respond to structural and functional requirements of the body
biocompatible
communicate with ECM
provide mechanical support
o transportation of nutrients and waste secretion in the engineered tissue
3D engineered tissue needs to be vascularized with a vascular capillary network
oxygen is directly consumed, and new vessels are formed only after several days
o mass production and commercialization of the engineered tissues
manufacturing conditions and quality control strategies
providing long-term storage and shipping facilities while ensuring that the structure and function of the tissues are intact
4 main types of technologies:
- Genetic Engineering
- Vaccines
- Gene Transfer Therapy
- Genome Editing
Genetics studies how
living organisms inherit features from their ancestors – for example, children often look like their parents
Traits are carried in DNA as instructions for constructing and operating an organism. These instructions are contained in segments of DNA called
genes
The function of genes
provide the information/instructions needed to make molecules called proteins in cells (which carry out these instructions)
How many jobs can a protein do?
one (it’s a specialist)
Genes tell cells what to do by telling them _______ and in __________.
which proteins to make; what amounts
transcription
When a gene is read by a cell the DNA sequence
is copied into a very similar molecule called
RNA
Transcription is controlled by other DNA
sequences such as
promoters
The RNA copy made from a gene is then fed through a structure called a _____, which translates ________
ribosome; the sequence of nucleotides in the RNA into the correct sequence of amino acids, amino acids join together to make complete protein chain
translation
new protein then folds up into its active form.
The process of moving information from the
language of DNA into the language of amino
acids
a feature of an organism is called a
trait
Where do traits come from?
often inherited, or come from the interaction between inherited features and the environment
Different forms of one type of gene are called different _____ of that gene.
alleles
mutations are:
random events that change the sequence of a gene and therefore create a new allele
genetic disorders (“single-gene defects”) w/ examples
caused by single allele of a gene and are inherited in families
- CF
- hemophilia
- sickle cell anemia
- Duchenne muscular dystrophy
CF; caused by what gene and what trait?
caused by mutations in a single gene called CFTR and is inherited as a recessive trait.
What is breast cancer caused by
result of large number of alleles + environment/lifestyle
genetic engineering (genetic modification)
uses laboratory-based technologies to alter the
DNA makeup of an organism.
* This may involve changing a single
base pair (A-T or C-G), deleting a
region of DNA or adding a new
segment of DNA
genetic engineering led to the production of medically important products:
- human insulin
- human growth hormone
- hepatitis B vaccine
- genetically-modified organisms (disease resistant plants)
live attenuated vaccines + examples
contain live virus particles that have been weakened to keep them from causing disease (might not be suitable for compromised immune systems)
- MMR, chicken pox, COVID
inactivated vaccine + examples
contain whole virus particles that have been killed or inactivated to keep them from causing disease
- safer (dead), require booster
- polio, few COVID
replicating viral vector vaccine + examples
use low pathogenic viruses and convert them into viral vectors that produce some of the same proteins as the disease-causing virus
- strong immune response
- used in vet med
non-replicating viral vector vaccine + examples
similar to replicating viral vaccines, but cannot replicate (replication genes deleted)
- improved efficacy and safety
- ebola
DNA vaccine
use DNA plasmids containing gene for SarsCov-2 + additional genetic elements that will produce the same antigenic proteins
- not used in humans
RNA vaccines
mRNA that will produce some of the same antigenic proteins as the disease-causing virus
- may trigger unintended immune response
- not used in humans
subunit vaccines
antigenic protein from disease causing virus without causing any genetic material
- relatively safer; no genetic material and no replication in body
- HPV, pertussis, hepatitis B
Gene transfer therapy
The insertion of genes into an individual’s cells and tissues to treat a disease, and hereditary diseases in which a defective mutant allele is replaced with a functional one. Although the technology is still in its infancy, it has been
used with some success.
CFTR genes
provides instructions for making a
protein called the CF transmembrane conductance
regulator (CFTR). This protein functions as a channel across the membrane of cells that produce mucus, sweat, saliva, tears, and digestive enzymes. Mucus is a slippery substance that lubricates and protects the lining
of the airways, digestive system, reproductive system, and other organs and tissues.
More than 1,000 mutations in the CFTR gene have been identified in people with cystic fibrosis.
a _____ must be used to deliver the therapeutic
gene to the patient’s target cells
vector
the most common type of vectors are _____ that
have been genetically altered to carry normal human DNA
viruses
Gene transfer therapy process (3):
Target cells such as the patient’s liver or lung cells are infected with the vector.
The vector then unloads its genetic material containing the therapeutic human gene into the target cell.
The generation of a functional protein product from the therapeutic gene restores the target cell to a normal cell.
Types of Gene Therapy (2)
- germ line gene therapy
- somatic gene therapy
germ line therapy + is it allowed?
- In the case of germ line gene
therapy, germ cells, i.e., sperm or
eggs, are modified by the
introduction of functional genes,
which are ordinarily integrated into
their genomes. - Therefore, the change due to
therapy would be heritable and
would be passed on to later
generations. - Theoretically, should be highly
effective in counteracting genetic
disorders. However, this option is
prohibited for application in human
beings, at least for the present, for a
variety of technical and ethical
reasons.
Somatic gene therapy
- Somatic cells are named based on the
Greek term soma. In Greek, soma means
body. Every cell type in an organism’s
body, except the reproductive cells, is a
somatic cell. More simply put, a somatic
cell is a non-sex cell. - In the case of somatic gene therapy,
therapeutic genes are transferred into
the somatic cells of a patient. - Any modifications and effects will be
restricted to the individual patient only,
and will not be inherited by the
patient’s offspring.
Four methods of gene therapy
- viral vectors
- homologous recombination
- selective reverse mutation
- regulation
viral vectors
A normal gene may be inserted into a
nonspecific location within the genome to replace a nonfunctional gene. (Most common approach.)
homologous recombination
abnormal gene swapped for normal gene; involves a genetic exchange between two similar or identical strands of DNA). (Widely used in cells to accurately repair double-strand breaks in DNA)
selective reverse mutation
returns the gene to its normal function
regulation
the degree to which a gene is turned on or off of a particular gene could be altered
Potential Problems with Viral Vectors
- Trouble preventing undesired effects.
- Ensuring the virus will infect the correct target cell in the body.
- Ensuring that the inserted gene doesn’t disrupt any vital genes already in the genome.
retrovirus
virus with an RNA genome that replicates by using
a viral reverse transcriptase enzyme to transcribe its RNA into DNA in the host cell. The
virus thereafter replicates as part of the host cell’s DNA.
example of retrovirus
HIV; can lead to AIDS
Using Retroviral Vectors in Gene Therapy: issue
If genetic material happens to be inserted in the middle of one of the original genes of the host cell, this gene will be disrupted (insertional mutagenesis). If the gene happens to be one
regulating cell division, uncontrolled cell division (i.e., cancer) can occur.
Adenoviruses (what is it + where do they effect + how does it help_
Viruses that carry their genetic material in the form of double-stranded DNA.
They cause respiratory, intestinal, and eye infections in humans (especially the common cold).
This vector system has shown real promise in treating cancer.
– The first gene therapy product to be licensed to treat cancer is an adenovirus.
a German hematologist named Gero Hütter cured a man who had HIV infection by
repeated hematopoietic stem cell transplantation with a CCR5 mutation
CCR5 mutation (other name + what does it do?)
resistant to certain strains of HIV infection
- delta 32 mutation
Glybera (alipogene tiparvovec)
treatment for the ultra-rare genetic disease lipoprotein lipas deficiency (LPLD) under exceptional circumstances
LPLD (how many people does it effect + what happens)
LPLD affects no more than two people per million in the general population. People with LPLD cannot break down fat, and must manage
their disease with a restricted diet. However, dietary management is difficult, and a high proportion of patients suffer life-threatening
pancreatitis.
Clinical trials of gene therapy in people have shown some success in treating certain diseases, such as:
- Severe combined immune deficiency (SCID)
- Hemophilia
- Blindness caused by retinitis pigmentosa
- Cancer:
– Leukemia
– Lymphoma - Blood disorder :
– Sickle Cell Disease
– Beta thalassemia - Spinal Muscular Dystrophy
Ethical Issues for Genome Editing (4)
- safety
- informed consent
- justice and equity
- genome-editing research involving embryos
Ethical Issues for Genome Editing (safety)
The possibility of off-target effects (edits in the wrong place) and mosaicism (when some
cells carry the edit but others do not). It might affect the development of a fetus in
unexpected ways or have long-term side effects that are not yet known
Ethical Issues for Genome Editing (informed consent)
Some people worry that it is impossible to obtain informed consent for germline therapy
because the patients affected by the edits are the embryo and future generations. The
counterargument is that parents already make many decisions that affect their future
children, including similarly complicated decisions such as PGD with IVF. Researchers and
bioethicists also worry about the possibility of obtaining truly informed consent from
prospective parents as long as the risks of germline therapy are unknown
Ethical issues for genome editing (justice and equity)
A concern that genome editing will only be accessible to the wealthy and will increase
existing disparities in access to health care and other interventions. Some worry that taken
to its extreme, germline editing could create classes of individuals defined by the quality of
their engineered genome.
Ethical Issues for Genome Editing (genome-editing research involving embryos)
Moral and religious objections to the use of human embryos for research. In the U.S.,
federal funds cannot be used for any research that creates or destroys embryos. In
Canada, the AHR Act allows human embryo research only if the embryo to be used in the
research is no longer needed for reproductive purposes and both gamete donors and the
individual(s) for whom the embryo was created have given their consent for its research
use in accordance with the regulations
Challenges for Gene Therapy (6)
- short-lived nature of gene therapy
- immune response
- problems with viral vectors
- multigene or multifactorial disorders
- insertional mutagenesis
- religious concerns
Multigene or multifactorial disorders
Conditions or disorders that arise from mutations in a single gene are the best candidates for gene therapy. Unfortunately, some of the most commonly occurring disorders, such as heart
disease, high blood disease, Alzheimer’s disease, arthritis, and diabetes, are caused by the combined effects of variations in many genes
Insertional Mutagenesis
If the DNA is integrated in the
wrong place in the genome, for example in a tumor suppressor gene, it could induce a tumor (e.g., X-SCID clinical trials)
Problems with viral vectors
Viruses, while the carrier of choice in most gene therapy studies, present a variety of potential problems to the patient —toxicity, immune and inflammatory responses, and gene control and targeting issues. In addition, there is always the fear that the viral vector, once inside the patient, may recover its ability to cause disease
Immune response
The risk of stimulating the
immune system in a way that reduces gene
therapy effectiveness is always a possibility.
Furthermore, the immune system’s enhanced
response to invaders it has seen before makes it
difficult for gene therapy to be repeated in patients
Short-lived nature of gene therapy
Before gene therapy can become a
permanent cure for any condition, the
therapeutic DNA introduced into target cells
must remain functional and the cells
containing the therapeutic DNA must be
long-lived and stable.
* Problems with integrating therapeutic DNA
into the genome and the rapidly dividing
nature of many cells prevent gene therapy
from achieving any long-term benefits.
* Patients will have to undergo multiple rounds
of gene therapy.
For what purposes was gene therapy originally developed?
o introduce a new gene into cells to help fight a disease
o introduce a non-faulty copy of a gene to stand in for the altered copy causing disease
Describe 3 uses for genome editing
o fix a genetic alteration underlying a disorder, so the gene can function properly
o turn on a gene to help fight a disease
o turn off a gene that is functioning improperly
o remove a piece of DNA that is impairing gene function and causing disease
What is the role of proteins in gene therapy?
o gene therapy: alters genetic code to recover the functions of critical proteins
o the instructions for making proteins are carried in a person’s genetic code; mutations in code can impact the production of function of proteins that are critical to how the body works
o fixing or compensating for disease-causing genetic changes through gene therapy may recover the role of these important proteins and allow the body to function as expected.
How is gene editing different from gene transfer therapy?
gene editing introduces molecular tools to change the existing DNA in the cell, instead of introducing new genetic material into cells
Why are viruses used as vectors?
they can deliver the material by infecting the cell (modified so they can’t cause disease when used in people)
What are the risks of using viral vectors?
o the virus may trigger a dangerous immune response
o vectors that integrate the genetic material into a chromosome can cause errors that lead to cancer
What is an alternative to using viral vectors?
o nanoparticles as vectors: deliver the genetic material or gene-editing components into cells
designed with specific characteristics to target them to particular cell types
less likely to cause immune responses
easier to modify for specific purposes
Describe 5 ethical concerns about gene therapy.
o how can “good” and “bad” uses of these technologies be distinguished?
o who decides which traits are normal and which constitute a disability or disorder?
o will the high costs of gene therapy make it available only to the wealthy?
o could the widespread use of gene therapy make society less accepting of people who are different?
o should people be allowed to use gene therapy to enhance basic human traits such as height, intelligence, or athletic ability?
What is CAR T cell therapy and how does it work?
o combines the technologies of gene therapy (introduces cells to the body that have a particular function to help treat a disease) and cell therapy (cells have been genetically altered to give them the special function)
o introduces a gene to a person’s T cells, which are a type of immune cell; provides instructions for making a protein, called the chimeric antigen receptor (CAR), that attaches to cancer cells. The modified immune cells can specifically attack cancer cells
How does RNA therapy work?
o use pieces of RNA, which is a type of genetic material similar to DNA, to help treat a disorder
o the pieces of RNA interact with a molecule called messenger RNA
o mRNA uses the information in genes to create a blueprint for making proteins.
o can influence how much protein is produced from a gene, which can compensate for the effects of a genetic alteration
o antisense oligonucleotide (ASO), small interfering RNA (siRNA), and microRNA (miRNA) therapies
What does “epigenetic” mean and what is epigenetic therapy?
o epigenetic: behaviours and environment can cause changes that affect the way your genes work; reversible and do not change your DNA sequence
o epigenetic therapy: affects epigenetic changes in cells; special modifications (tags) attached to DNA that control whether genes are turned on or off
epigenetic therapies are used to correct epigenetic disorders that underlie genetic disorders
medical technology (the groundwork)
- life support
- substitute for body structure or function
- medical treatment
- measurement of living body function
Medical devices are applied in one or more of the following areas:
- life support (e.g., dialysis, mechanical ventilator);
- substitution for body structure or function (e.g., implanted electrical stimulator, prosthetic limb, cochlear implant);
- medical treatment (e.g., injection devices);
- measurement (e.g., glucose monitor, fMRI).
“Device” means any article, instrument, apparatus or contrivance, including any component, part or accessory thereof, manufactured, sold or represented for use in
(a) the diagnosis, treatment, mitigation or prevention of a disease, disorder or abnormal physical state, or its symptoms, in human beings or animals,
(b) restoring, correcting or modifying a body function or the body structure of human beings or animals,
(c) the diagnosis of pregnancy in human beings or animals, or
(d) the care of human beings or animals during pregnancy and at and after birth of the offspring, including care of the offspring,
and includes a contraceptive device but does not include a drug
FDA grouped medical devices into 16 medical specialties referred to as
panels
Classification is ___ based, that is, the ___ the device poses to the patient and/or the user is a major factor in the class it is assigned.
risk
reusable surgical scalpel
class I
contact lenses
class II
orthopaedic implants
class III
HIV test kits
class IV
bandages
class I
epidural catheters
class II
glucose monitors
class III
pacemaker
class IV
culture media
class I
pregnancy test kits
class II
dental implants
class III
angioplasty catheters
class IV
surgical gloves
class II
haemodialysis systems
class III
surgical gloves
class II
diagnotic ultrasound systems
class III
class I
Devices in this category are those whose failure or misuse is unlikely to result in serious consequences.
cane
class I
manual breast pumps
class I
surgical microscope
class I
sphygmomanometers
class I
class II
These are devices including many diagnostic instruments whose misuse, failure or absence (e.g. out of service with no replacement available would have a significant impact on patient care, but would not be likely to cause direct serious injury
ECG/EEG
class II
treadmills
class II
ultrasound sensors
class II
endoscopes
class II
class III
High risk devices are life supports, critical monitoring, energy emitting and other devices whose failure or misuse is reasonably likely to seriously injure patient or staff.
Anesthesia units
class III
Apnea monitors
class III
Aspirators
class III
Fetal monitors
class III
Incubators
class III
Infusion pump
class III
amylase test system
device intended to measure the activity of the enzyme amylase in serum and urine
- used primarily for the diagnosis and treatment of pancreatitis (inflammation of the pancreas).
Cricothyrotomy
emergency procedure to avoid death from suffocation due to upper airway obstruction (e.g. glottis edema, foreign body, larynx carcinoma) when intubation or tracheotomy are impossible
What is the relationship between medical devices and quality of life? (How direct or indirect is this relationship?
o increase the lifespan/improve the quality of life
o positive impact on quality of life and well-being
o no direct correlation between medical devices and QoL
improvements are more influenced by the opportunities to engage in life activities and participate in society
What is the difference between a medical device and an assistive device?
o medical devices: (sustains life)
o assistive devices: designed for intervention at the component levels described in the ICF as Activities and Participation
self-support (e.g., powered wheelchair, print magnifier, augmentative communication device)
support from others (e.g., toilet and bath transfer devices; assistive devices for feeding)
