Week 3 Random Flashcards
Where does the implantation usually occurs?
Posterior-Superior side of uterus
When is the implantation complete?
11-12 day because of the plug
What is the organ system that becomes functional by the 8th week?
Cardiovascular
When does the embryo has the shape of a human?
Week 8
What are phases in embryonic development?
growth (mitosis; cell division)
morphogenesis (making structures like heart, liver)
differentiation (maturation of physiological processes)
What are derivatives of ectoderm?
Neuroectoderm that gives rise to all CSN and PSN
Epidermis
What induces neurulation?
Precordal plate and notochord
What is neurulation? Describe steps
Folding creates neural tube
- BMP4 blocked -> prechordal plate and notochord induces neural plate
- neural plate forms neural tube
- fusion from cranial to caudal
- neuphores close cranial 25 caudal 27
- neural crest formation
What is neuropores?
The openings after neurulation (posterior and anterior)
What is neural plate converted after it rolls?
Neural tube
BMP4
BMP4 is blocked allowing induction of neural plate by notochord and prechordal plate
Direction of fusion of neural tube
Cranial to caudal
When does cranial neuropore and caudal neuropore close?
cranial neuropore closes day 25 caudal neuropore closes day 27
What is forming besides neural tube during neurulation?
Neural crest
Neural Crest Cells:
Where do they come from?
Where do they migrate?
What do they become?
from neural folds migrate to mesenchyme form PNS and a lot more:
Connective tissue and bones of the face
Cranial nerve ganglia
C cells of the thryoid gland
Conotruncal septum in the heart
Odontoblasts
Dermins in the face and neck
Spinal (dorsal root) ganglia
Sympathetic chain and preaortic ganglia
Prarasympathetic ganglia of the gastrointestinal tract
Adrenal medulla
Schwann cells
Glial cells
Arachnoid and pia matter
Melanocytes
Define Mesenchyme
It is connective tissue of mesoderm.
What is epidermal covering?
Derivative of ectoderm
epidermis, sweat glands, sebaceous glands, mammary, glands, hair, nails, cornea, anterior pituitary, enamel, internal ear, lens of the eye
What are subdivisions of ectoderm?
Neuroectoderm: CNS, PNS
Ectoderm: epidermis, sweat glands, sebaceous glands, mammary glands, hair, nails, cornea, anterior pituitary, enamel, internal ear, lens of the eye
Name mesoderm parts
Axial
Paraxial
Intermediate
Lateral
Axial mesoderm
Forms notochord cranial
Limited by prechordal plate caudal and caudal eminence
Paraxial mesoder
Somitomeres
in head: somitomeres1-7 + neural plate -> neuromeres -> wonderful thing
in body: somitomeres -> somites
* 3/day can be used as a clock
Which direction do somites grow?
Cranial to caudal
Types of somites
sclerotome cells migrate medially to form bones (vertebrae, ribs, some base of the skull)
dermomyotome dermatome cells migrate under ectoderm to form connective tissue of the skin – dermis myotome cells migrate to form skeletal muscle
What do somites pull with them?
The innvervations of spinal cord
What is important about dermatomyotome location?
Each dermatomyotome retains its own segmental innervation from its origin
Intermediate mesoderm
Forms most organs (CT, smooth muscle and epithelial linings) in both the urinary and genital systems.
** The endoderm provides the remaining epithelial linings of some UG organs.
Cephalocaudal Folding
Rapid head and tail growth causes the embryo to curl toward the ventral surface
Lateral Folding
endoderm becomes folded into a long narrow tube within the embryo.
mesoderm continues to separate out ectoderm from endoderm.
the ectoderm and amniotic cavity completely encircle the embryo.
the ectoderm forming the outer covering of the embryo
What cavities are formed from extraembyonic celoem?
intraembryonic cavity Thoracic and abdomainal cavity
Lateral Plate Mesoderm
somatic -> connective tissue and smooth muscle of body wall, bones and cartilage of limbs and limb girdles
splanchnic -> connective tissue and smooth muscle lined organs and ALL tissues of cardiovascular system
In which location lateral plate mesoderm does not split?
Head
Endoderm Derivatives
forms the epithelial lining of GI tract mesoderm and endoderm induce each other to form specific GI organs epithelial components of several other organs: pharyngeal buds, lung buds, liver, pancreas and gall bladder buds
Pharmacology definition
the study of the interactions of chemicals, other than foods, with living systems. It is a science based upon an understanding of organic chemistry, biochemistry, physiology, pathology and microbiology that focuses on the mechanism of action of drugs on living systems.
Pharmacology subcategories
Pharmacodynamics: Mechanisms of Drug Action
Pharmacokinetics: Absorption, distribution, metabolism and elimination of drugs.
Therapeutics: The application of pharmacology to the problems of clinical medicine.
Chemotherapy: The use of drugs, which ideally have little effect on the host (patient) but destroy or retard the growth of invading cells and organisms.
Safety Pharmacology: A relatively new discipline that is focuses on the MOA of unwanted effects of drugs in humans during drug product development.
Toxicology: The pharmacology of the harmful effects of poisons, environmental and industrial chemicals and drugs on the human body.
Pharmacy definition
The science broadly interested in all aspects of drugs, with two primary emphases: one on the manufacture, compounding, preparation and dispensing of drugs; the other on the therapeutic management of drug treatment of patients; therapeutacist.
Drug names
Chemical name: Any typical organic chemical name.
Generic name: The assigned name of a drug, by which it will be known throughout the world no matter how many different companies manufacture it.
Official name: This is the name by which a drug is listed in one of the following official publications: a) U.S. Pharmacopoeia, b) National Formulary, c) U.S. Adopted Names.
Trade name: The name that is given by a particular company that is manufacturing the drug.
Who is responsible for regulating laws regarding drugs? How?
FDA
Right to regulate, recall, and safety aleart
Drug Discovery Map
Initially Drug Discovery Process
(basic lab) Lead identification and optimization: Classical medicinal chemistry, Molecular modeling, Natural product screening, Novel biotechnology, Serendipity
(confirmation in models) Pharmacologic evaluation: In vitro receptor binding, Cell-based assays, Animal disease models
(toxicity) Preliminary assessment of development challenges: Toxicology, Pharmacokinetics, In vitro tests, Exploratory, dose range finding studies, Scale-up potential, Costs of clinical evaluation
Investigational New Drug (IND)
Application submitted by a sponsor to study:
Chemical and biological activities
Dosage form specifications for humans
Quality control details
Description of company facilities and personnel
Scientific qualifications of the investigators
Specific details of the protocol to be followed
Phases in human testing
Phase 1: 9-18mo 20-100 health = safety; tolerability; administration
Phase 2: 18-24mo 30-40 control & subject = response ; dosage ;
Phase 3: 2-4yr 100-1000+ experimental = clinical benefit ; RCT
Drug is considered safe.
Phase 4: 1-2yr = broader population; compares effectiveness with other drugs
Items that need to be completed in order to receive license for a new drug.
To obtain license for a new drug:
Completed results of Phase I, II and III
Long term toxicity studies on animals
Effects on fertility and reproduction and young animals
GLP
Good laboratory practices
Are regulatory guidelines followed by a validated laboratory to ensure each and every step of the study/experiment is validated. So that every step performed in a study/experiment can be precisely and accurately repeated.
Why G proteins are important?
these membrane proteins represent more than half the current drug targets and a market of tens of billions of dollars annually
all tisues, organs, and cells express GPCRs
How many transmembrane folds are in GPCRs?
7
How G-protein is activated?
Signal molecule binds to GPCR
Alpha subunit is phosphorylated
It dissociates from beta-gamma complex
Types of GPCRs
Functions cAMP, cGMP, and Ca2+
2nd messenger
(cAMP): Binds to PKA (Gs); Activates Na+ channels in olfactory neurons (Golf)
(Ca++): Binds to PKC (Gq)
(cGMP): Opens Na+ channels in rod cells (Gt)
How does Vibrio cholerae affects intestinal cells?
Locks GPCRs in active state
How does Pertussis toxin (Bordetella pertussis) affects respiratory cells?
Inactivates Gi protein leading to cAMP overproduction
Produces uncontrollable, violent coughing
Downstream effect of Gi
Alpha – inhibits adenylyl cyclase
Beta/Gamma – Opens potassium channels
Downstreams of Gs
Gs.
alpha – Activates adenylyl cyclase
cAMP binds to regulatory units of PKA
activated PKA activates CREB causing CREB binding protein (CPB) to cyclic AMP response element (CRE)
Which G receptors is involved in fight or flight in muscle?
Gs
Downstream of Gq
alpha – Activates phsopholipase C
Breaks down PI(4,5)-biphosphate to inositol 1,4,5 (IP3) and diacylglycerol
IP3 opens calcium channels in ER
Calcium and diacylglycerol activates protein kinease C
How Ca++ is kept low in cell?
Exchangers
Ca++ pump
Ca++ binding
Ca++ import to mitochondria
Ca++ pump to ER
How cystolic calcium is changed?
Nerve terminal: Ca++ bidns to voltage-gated Ca++ channels
Cell: ligand binds, signal to release Ca++ from ER
Downstream of Golf
alpha activates adenylyl cyclase
cyclic AMP causes Na+ channels to open
Downstream of Gt
Light -> Activate rhodopsin -> Gt -> PDE -> less cGMP
Na+ channels close; so now the rod cell is hyperpolarized
How GPCR can be desensitized?
GPCR kinease phosphrylates GPCR
Arrestin binds to these phosphate
How many times does tryosine kinease passes through a membrane?
1
How is secondary messenger is connected with fight or flight response?
(Downstream of Gs)
cAMP activates PKA
PKA phosphorylates and activates glycogen phosphorylase that adds phosphate to glycogen and leads to breakdown of it to glucose-6P
PKA phosphorylates and inactivates glycogen syntahse by
5 classes of RTK
Subfamilies of RTKs
Epidermal growth factor -> EGF receptors
Insulin -> Insulin redcetpor
Insulin-like growth factors (IGF1 and IGF2) -> IGF receptor-1
Nerve Growth Factor (NGF) -> Trk A
Platelet derived growth factors -> PDGF receptors
Macrophage-colony-stimulating factors (MCSF) -> FGF receptors
Vascular endothelail growth factor (VEGF) -> VEGF receptors
PDGF receptor (RTK)
Signaling proteins with SH2 domains bind to PO4-Y docking sites on an activated
Insulin and IGF-1 receptor (RTK)
Have phosphorylated docking stations that bind proteins
Ras Superfamily
Ras (relay signals from RTKs)
Rho (Relay signals from surface to cystoskeleton)
ARF (formation of protein vessicles)
Rab (regulate intracellular traffic)
Ran (regulates mitotic spindle)
Activation and inactivation of Ras
What can happen when tyrosine kinease receptors are phsophrylated?
Dimerize and autophosphorylate
Phosophates provide docking stations
Phosphates near kinease domain increases the kinease activity
Sometimes docking proteins might mediate signal (e.g. IRS-1)
SH2 domain binds to
Tyrosine-(P)
SH3 domain binds to
Poly proline regions
What protein provides crucial link between receptor Tyr kineases and the downstream signaling cascades?
Monomeric Ras
How Ras is activated?
RTK is activated
Adaptor proteins binds with SH2 to RTK and SH3 to Ras-GEF
Ras is activated
Downstream effects of RAS
RAS -> MAP KKK (Raf) -> MAP KK (Mek) -> MAP K (Erk)
MAP K can be phsoporylated both on theorenine and tyrosine leading to specificity
What binds to PH domain?
Phsophatidylinositol (PI) that can be altered by phosporylation (PIP2 and PIP3 by PI3 kinase)
PI3 kinase signaling pathway: B cell activation
B cell receptor causes PI(4,5) to be phosphorylated to PI(3,4,5)
PI(3,4,5) binds to BTK that binds and activated PLC-gamma
PLC-gamma cleaves PI(3,4) to diacylglycerol and IP3
Clonal expansion
PI3 kinase and Akt promote cell survival
PI(3,4,5)P3 activates PDK1
PDK1 and mTOR phosphorylates Atk
Atk dissociates from PI(3,4,5)P3 and inactivates Bad
Bad release apoptosis inhibitorty protein=
Receptor is
–A protein that binds a neurotransmitter/modulator
–A protein that binds a small molecule
–A protein that binds another protein
–A nucleic acid that binds a protein
–A macromolecule that binds a drug
–A macromolecule that binds a toxicant
Receptor Theory
The Hill-Langmuir Equation
(eq) D + R <–> DR ->> Effect
rate of reaction is proportional to the product of the concentration of the reactant
Hill-Langmuir Equation
D+R<->DR
Saturation Binding Isotherm
Scatchard plot
Concentration/Dose-Response Curves
Linear vs. SemiLog
efficacy / Intrinsic activity
the relative maximal response caused by a drug in a tissue preparation
Potency
how much of a ligand is needed to cause a measured change
Types of receptors
Channel
G-protein
RTK
Intracellular receptor
How attenuation can occur?
Refractoriness
Desensitization
Down regulation
Tachyphylaxis
Supersensitivity
Quantal Dose-Response
Describe population rather than single individual responses to drugs
all-or-none
death, pregnancy, cure, pain releif
Graded Concentration-Response Curves
Inifinite number of intermediate states
vessel dialtion, blood pressure change, heart rate change
Types of antagonism
Chemical: interaction of two drugs in solution such that the effect of active drug is lost
Physiological: Interaction of two drugs with opposing physiological actions
Pharmacological: Blockade of the action of a drug-receptor interaction by another compound
Competitive Antagonists vs. Non-Competitive Antagonists
Competitive Antagonists
- bind to same site on receptor as agonists
- inhibition can be overcome by increasing agonist concentration (reversible)
- primarily affect agonist potency
- clinically useful
Non-Competitive Antagonists
- bind covalently to same site as agonist (irreversible) or to a site distinct from that of agonist (irreversible or reversible)
- inhibition cannot be overcome by increasing agonist concentration
- primarily affect efficacy
- limited clinical use
Spare receptors
Pool of availible receptors exceeds the nubmer required for a full response
Drug desensitization types
Recepotor mediated: loss of receptor function (fast); reduction of number of recetors (slow)
Non-Receptor Mediated: reduction of signalling, reduction of drug concentration
Full agonist
Partial agonist
Inactive compound
Inverse agonist
Sites of hematopoesis
Yolk Sac (Mesoblastic phase 2wk) +RBCs
Liver (Hepatic phase 6wk) +WBCs
Spleen (Splenic phase (2nd tri)
Bone Marrow (Myeloid phase 2nd tri)
Sternum, ribs and vertebra (Fatty replacement in long bones 20 yrs)
* Anemia can cause hematopoesis in spleen
Where lymphocytes become immunocompetent?
T = Thymus
B = Bone Marrow
Pluripotent vs. Progenitor vs. Precursor
Pluripotent - capable of differentiating into different types of cells
Progenitor cell - unipotent (committed to a particular cell line), and capable of self-renewal
Precursor cell - immature unipotent cell, not capable of self-renewal
Stromal cells in bone marrow
fibroblasts, macrophages, adipocytes, osteoblasts, osteoclasts, endothelial cells, hematopoetic supportive stroma, osteocyte
Formed elements
Blood
Two blood cell lines
Myeloid & Lymphoid
BFU
CFU
CSF
BFU=blast forming unit
CFU=colony forming unit
CSF=colony stimulating factor
Erythropoesis
Epo secreted by Kideny
Both BFU-E and CFU-E are stimulated by epo to divide
CFU-E’s when stimulated mature into RBC precursors
Progenitor cells form spherical cluster around macrophages known as “nurse cells”
Macrophages phagocytize extruded red cell nuclei
Reticulocytes that are released into circulation mature in the blood stream
Granulocytopoiesis
CFU for each cell line give rise to blasts
CFUs are stimulated to proliferate and differentiate by CSFs and other cytokines (chemical cell signals)
Granulocytes mature in the bone marrow in the hemopoietic cords
In cases of need such as infection the bone marrow will respond by releasing almost mature neutrophils(bands or stabs) into the circulation
Neutrophils will marginate to the inner wall of the blood vessels and quickly release when needed-allowing for a quick response in injury, inflammation
Monocytopoiesis
Also arise from CFUs, when mature enter circulation for a short time until migrating into tissue to become macrophage
Platelet formation
CFU>megakaryoblast>megakaryocyte 40-100 uM
Single multilobed nucleus can give appearance of being multinucleated
Located next to sinusoids in bone marrow and break off bits of cytoplasm into the circulation that break up into platelets
Lymphocytopoeisis
Lymphocytes are derived from CFU-Ly stem cells>B or T CFU progenitors
B cells develop and become immunocompetent in the bone marrow
T cells develop in the bone marrow and become immunocompetent in the thymus
Examination of bone marrow
Bone marrow: aspirate (cellular detail)
biopsy: (structure and ratios of cell populations)
Blood: peripheral smear obtained from a venous blood sample
Structure of bone marrow
bony trabeculae
Stromal cells provide a supportive framework for islands of blood cells called hematopoietic cords to develop
Vascular channels provide nutrients and are where new blood cells enter circulation
Over time hemopoietic cords replaced with adipocytes
RBCs charactersitics
no nucleus
no organelles
carbonic anhydrase
salmon pink biconcave discs
lipid bilayer supported by lattice of spectrin and actin
Carbohydrate chains on the membrane surface are the A and B antigens
Rh complex set
Increased surface area for gas exchange
7um
Monocytes function
Monocytes circulate for a day or two and then enter tissue through postcapillary venules and become macrophages
Phagocytosis of cellular debris bacterial antigen presentation to lymphocytes
Neutrophils function
Neutrophils migrate through post capillary venules to phagocytize and destroy bacteria
(this also kills the neutrophill)
Have membrane receptors for antibodies
Release substances involved in the inflammatory response
pus is an accumulation of dead leukocytes, bacteria, extracellular fluid
Eosinophil function
Binding substances released by other inflammatory cells
Release substances to inactivate histamine and other inflammatory mediators
Destroy parasites
Basophil function
Release granule contents that cause allergic reaction
Histamine>>leaky vessels, vasodilation, bronchial smooth muscle contraction
Interesting hypothesis not pertinent to this session: these cells may have a some point provided protection against certain kinds of venom (verbal opinion from an allergist)
Platelets function
Damaged endothelial cells release substances promoting vasoconstriction and clotting including von Willebrand factor (vWF)
Platelets adhere to exposed collagen in basement membrane enhanced by vWF
Platelets are activated to degranulate and adhere to one another
platelets aggregated into a thrombus or clot
What 2 factors play a role in mRNA stability and degradation?
Poly-A-tail and G-cap
eIF4G is connected to Poly-A-tail
eIF4E is conntected to 5’ cap
Deadenylation nuclease (DAN)
) associates with the 5’ cap of the mRNA and then shortens the poly-A tail in the 3’ to 5’ direction
Ribosome structure
80S
60S (2.8Mb) = 5S+28S+5.8S + 49 proteins
40S (1.4Mb) = 18S + 33 Proteins
Translation initiation
eIF2-GTP associates with amnioacyl-tRNA and small ribosomal subunit
eIF4E/eIF4G comes with mRNA
ATP is hydrolized and complex searches for Kozak
Large subunit binds GTP is hydrolized
EF-Tu
EF-G
eEF-1
eEF-2
Post translational control
Proteolysis (non-reversible)
Folding
Adding functional groups
Structural changes
Processing
Removal of start methionine
What are some hormone-induced cell responses that are mediated by cAMP?
What is the difference between fertilization and gestation age
Fertilization age (embryology) counter after fertilization (38 weeks)
Gestational or Menstrual Age (OBGYN) counter after LNMP (40 weeks)
Characteristics of Autosomal Dominant Inheritance
Recurrence 50%
Vertical transmission pattern
Equal males and females (usually)
Father to son is possible
Autosomal Dominant
Heterozygote frequency
2q
Autosomal Dominant
Familial Hypercholesterolemia
Related vs. nonrelated unaffected
Cannot determine related untested
Assume aa for unrelated untested
100% Cholesterol penetrance
Not 100% Cardiovascular disease penetrance
Autosomal Dominant
Homozygous Recessive Assumption of uneralted individual
For the purpose of calculating recurrence risk asume that unrelated individuals are unaffected unless disease frequency is >1/20
Characteristics of Autosomal Recessive Inheritance
Recurrence 25%
Horizontal transmission pattern
Equal males and females (usually)
Father to son is possible, consanguinity is seen
Autosomal Recessive
Disease frequency
Carrier frequency
Disease frequency q^2
Carrier frequency 2q
Autosomal Recessive
2/3 rule
Applies only when you know there is a possibility of homozygous
affected offspring, but the individual is not affected.
Test to detect Cystic Fibrosis
Sweat chloride test
Measures Cl- concentration
OCA1
tyrosine-negative albinism
autosomal recessive
Characteristics of X-linked recessive inheritance
Female carriers
Males are hemizygous
No male to male transmissions
More males affected
Examples of X-linked recessive inheritance
Hemophilia (1/10000) – clotting factor VIII (A) or IX (B)
Duchenne Muscular Dystrophy – (1/3500) dystrophin complex (die before reproduction age)
G6PD Deficiency – (1/10) [female carriers 1/5] Glucose-6-phosphate dehydrogenase low activity leading to anemia (by breakdown of cells) symptoms are observed after drug treatment (oxidative stress)
Haldane Principle:
in a population with a stable disease frequency
rate of spontaneous new mutation = rate of loss of alleles
Examples of X-linked dominant inheritance
hypophosphatemic rickets
Characteristics of X-linked dominant inheritance
No skipped generations
Twice as many females affected
No male to male transmission
Sex-influenced traits
pertaining to an autosomal genetic trait, such as pattern baldness or gout, that is expressed in both homozygotes and heterozygotes in one sex butonly homozygotes in the other sex.
Exmaples of sex-influenced trait
Baldness (X-linked = androgen receptor , autosomal dominant sex-influenced = csome 20)
androgenic alopecia (AGA)
In men with reduced androgen levels (i.e. testicular injury), no baldness seen until treated with androgens
In females with elevated androgen levels (i.e. adrenal tumors), hair loss observed
DNA extractio
Lyse cells, digest proteins and RNAs
Bind DNA (- charged) to + charged magnetic beads (low pH)
Wash beads containing DNA to remove contaminants (cell debris, membranes, proteins, RNAs)
Elute DNA from neutralized beads (high pH)
(Silica-based)
Gender typing
AMELX (Amelogenin)
gene is present on X and Y chromosomes but different introns
STRs vs. SNPs
SNPs used when DNA is degraded
SNP are less variable (paternal testing)
Epigenetic processes
- Regulation of histone modification and heterochromatin formation.
- DNA methylation
- Genomic imprinting DNMT-1 transfer patterns of methylations to a newly synthesized DNA after DNA replication
- Gene silencing
- X-chromosome inactivation
Antibiotics acting on Replication
Acyclovir:
Modified by viral thymidine kinease to become acyclo-GMP; it truncates DNA replication because it lacks 3’ OH
Actinomycin D
is an antibiotic anticancer drug that inhibits Pol
Antibiotics acting on Translation
BACTERIA ONLY
Tetracycline (blocks A site)
Streptomycin (prevents initiation to elongation)
Chloramphenicol (blocks peptidyl transferase)
Erythromycin (binds exit and prevent elongation)
BOTH BAC AND EUK
Puromycin (premature release of chain)
EUKARYOTES
Cycloheximide (blocks translocation)
Aniomycin (blocks peptidyl transferase)
Antibiotics acting on Transcription
BACTERIA
Rifamycin (binds to RNA Pol and prevent initiation)
BOTH BAC AND EUK
Actinomycin D (binds to DNA prevent movement of RNA Pol)
EUKARYOTES
a-Amanitin (bind to RNA Pol II)
4 sites on ribosome
E
P
A
mRNA binding
How does aminoacyl-tRNA synthetase ensures that right amino acid is connected to right tRNA?
What is Kozak sequence?
A/G-X-X-AUG-G
Hsp60
Molecular chaperone
Hemophilia
(1/10,000)
(A; B is 1/10 as common); clotting factors VIII (A) and IX (B).
Glucose-6-phosphate dehydrogenase (G6PD) deficiency
African populations (10% of African American men)
X-linked recessive
An acute but self limiting anemia secondary to intravascular breakdown of red blood cells (hemolysis).
Hemolysis occurs in response to oxidative damage to the RBC.
Symptoms observed after treatment with certain drugs (anti-malarials or antibiotics), or after other stresses (infection).
Red blood cells lack a nucleus and ribosomes and cannot make G6PD after they are formed, so supply is limited. G6PD regenerates NADPH which regenerates reduced glutathione which protects cells from oxidative stress.
