Module 12 wk2 Flashcards
( food microbiology)
T/F the more bacteria the longer the shelf life?
False - the more bacteria the shorter the shelf life
Why is food sampled?
- checks on hygienic production and handling techniques
- quality control and shelf life performance
- suspencion of being the cause of food poisoning
or as a result of consumer complaint - verification of quality of imported food
Give a list of microbiological tests to monitor food?
Total viable counts
Counts of coliforms
Counts of psychotrophs
Presence of pathogens – once make you ill
Presence of bacterial toxins – that they produce
Presence of fungi
Presence of mycotoxins – some are carsogenic so important
Indicator organisms – E. coli, enterococci
Describe the procedure of examining samples of food
- Refrigerate at 4°C until examination within 24 hours
- Homogenise (broken up to evely distribute) for 2 minutes in 100ml 0.1% buffered peptone water/0.9% saline 250 cycles stomacher or homogenised
- 10 fold dilutions in 0.1% peptone in 0.85% saline then plate
- TVC and Enterobacteriaceae
when interpreting results what does the presence of fecal organisms indicate?
Need for further investigation
What does the absence of target pathogens mean?
Means that the test only provides a degree of probability that they are not present in the food
Describe quantitive sampling
- The sample size is known
- There is no loss in storage
- Particles
- Viable counts
What do you do with templates when testing?
PLaces it over carcass and rub swap all over space, culture or put in enrichment media
What is total viable counts?
- It is the basis of international agreements and standards - for carcase meat and minced meat
Out of viruses, bacteria, parasites, and fungi which can multiply in food?
bacteria and fungi
5 types of bacterial pathogens in food?
- salmonella
- campylobacter
- E.coli
- clostridium - p and b
- Staphylococci
once you have quantitative culture what do you do next?
- pre-enrichment in peptone water and then enrichment in selective broth
- plate culture from enrichment broth on selective medium
How is Samonella confirmed in lab?
Biochemically
how is campylobactor confirmed in lab?
By API strip
Describe how campylobactor samples are retrieved from chickens?
Birds are hung unside down so feacal matter goes down to head and neck contaminating it so that is where they take sample from
T/F some people carry Staph. aureus all the time, some intermittently and some none.
Trueeeee ew
(girlie pop you carry it so idk why your saying ew)
How do you confirm Listeria?
By PCR to check for the listeriolyosin gene
T/F clostridium botulinum still today is fatal if ingested?
False - used to be fatal and paralyse but now we are able to neutalize toxin and have ICU
(Food standards + Food spoilage)
Whats does microbiology criteria provide?
- Provides guidance on acceptability of food and the manufacturing process
Provides objective and reference points to assist Food Business Operatives (FBO’s) to manage and monitor the safety of food - Can be used to validate and verify HACCP procedures and hygiene measures
How often should sampling take place on a meat plant?
Regular sampling should be taking place in the meat plant at least weekly
How many carcases are used per week to sample?
5
Using the destructive method what samples are taken?
4 tissue samples of 20cm^2
Using the non-destructive method what samples are taken?
100cm^2 sample
what organism is found in read-to-eat foods?
Listeria monocytogenes
what are actions if the criteria are not met for individual batches that the FBO must do
The FBO must ensure that individual batches that do not meet the criteria are disposed of safely or are reprocessed in an approved fashion
where do the microorgaminsm in food derved from?
raw materials, contamination during their production, in storage and by the purchaser
what are the different mechanisms of spoilage?
- Sugar fermentation with acid and gas production
- Protein hydrolysis – bacterial enzymes – proteases
- Digestion of complex carbohydrates – fungi – pectinases
- Lipolysis – lipolytic enzymes
- Oxidation of organic acids and alcohols
- Surface growth
T/F Staphylococci is a gram-positive spoilage organism?
True
T/F E.coli is a gram negative spoilage organism?
True
what are moulds sourced from ?
air, dust and condensation
If you see mould in black spots what is it?
cladosporium
If you see mould in white spots what is it?
sporotrichum
If you see mould in whiskers what is it?
Mucor
Bluish green moulds are?
Aspergillus, penicillium
(Endocrine Pathology - Intro)
What are the three types of intracellular signaling?
- autocrine
- paracrine
- endocrine
what is autocrine signalling?
cells respond to signals that they create themselveswh
what is paracrine signalling?
molecules produced by one cell act on neighboring cell
What is endocrine signalling?
Hormones produced by endocrine organs get into circulation and act on distant target cells
What is the definition of an endocrine gland?
Group of specialised epithelial cells that synthesis, store and directly release hormones into blood
What kind of hormones do endocrine gland release?
polypeptides, steroids, AA derivatives
what is an endocrine gland made up of?
An endocrine gland is made of cords and packets of specialized epithelial cells in a scanty fibrous stroma, that in turn is well vascularised by sinusoids/capillaries.
Describe primary endocrine hypofunction
- Failure of glandular development
- destruction of secretory cells
- biochemical defect in the synthetic pathway (looks normal, function not)
Describe the secondary mechinism of endocrine hypofunction
Destructive lesion decreases trophic hormones so reduced activity in second organ so signalling organ has problem meaning other does too
Describe the primary mechanism of endocrine hyperfunction
Abnormal cells secrete hormone in excess of bodily requirement s
Describe the secondary mechanism of endocrine hyperfunction
Abnormal cells in one organ produce too much trophic hormone which increases activity in the target organ
when there primary hyperfunction what hormone causes Acidophil adenoma (pituitary gland)? and what sign/lesion do we see?
Growth hormone and acromegaly
when there is primary hyperfunction what hormone causes Phaeochromocytoma? and what sign/lesion do we see?
noradrenaline and hypertension
when there is primary hyperfunction what hormone causes Parathyroid gland chief cell adenoma? and what sign/lesion do we see?
paratyroid hormone and fibrous osteodystrophy
when there is primary hyperfunction what hormone causes Pancreatic β-cell adenoma / carcinoma? and what sign/lesion do we see?
insulin and hypoglyceamia
when there is primary hyperfunction what hormone causes Thyroid follicular cell adenoma? and what sign/lesion do we see?
T3,T4 and increase in basal metabolic rate
What are the clinical results of endocrine disease?
Functional and clinical pathology abnormalities affecting one or more body system can be seen
What does primary anterior pituitary hypofunction cause?
- Aplasia
- congenital, toxic and viral
- destruction of the space-occupying lesion
- cystic Rathkes pouch
- abscess, granuloma
- neoplasm
what does secondary pituitary hypofunction cause?
Hypothalamic malfunction
What is the posterior pituitary hypofunction clinical syndrome?
Diabetes insipidus
What is the type of diabetes insipidus and what is it caused by when there is primary posterior pituitary hypofunction?
central DI
It is caused by the destruction of the pars nervosa meaning no ADH is produced
What is the type of diabetes insipidus and what is it caused by when there is secondary posterior pituitary hypofunction?
Nephrogenic diabetes insipidus which restricts renal tubules can’t respond to the ADH
Clinically what can be seen with central diabetes insipidus?
- ADH deficiency
- Lack of H2O reabsor[tion in tubules
- This leads to dilute urine, hypernatremia and dehydration
- PU/PD and low USG
What is the most common cause of pituitary hyperfunction?
Functional neoplasms within pituitary
In dogs where is it most common to see adenoma in the pituitary?
Pars Distalis
In horses where is it most common to see adenoma in the pituitary?
Pars Intermedia
In PPID pars intermedia dopamine is decreased all year round, if there is no inhibition of this what is caused?
Melanotrophs of pars intermedia synthesize excessive hormones, hyperplasia, micro and macroadenomas develop
An enlarged pituitary compresses the hypothalamus and causes clinical signs, what are these?
There is abnormal regulation of appetite, temp, seasonal sleep rhythms and hair growth
What are the clinical signs of PPID?
- Polyphagia, polyuria, polydipsia
- Hyperglycaemia
- Laminitis
- Generalised hyperhidrosis (sweating)
- Somnolence
- Striking hypertrichosis - hirsutism
What kind of disorder is Equine metabolic syndrome?
complex
What does Equine metabolic syndrome cause?
- Increased regional adiposity
- Insulin resistance - can lead to laminitis
- Altered metabolism due to adipocyte dysfunction leading to increased thrombosis, inflam and oxidant stress, altered vascular endothelial cell function
How would you differ between PPID and EMS?
- age of onset - EMS gen younger
- Additional clinical signs suggest PPID such as failed coat shed, excess sweating and skeletal muscle atrophy
- positive diagnostic test for PPID - increased plasma ACTH without pain
T/F Both PPID and EMS can coexist in one individual?
Trueeeeeeeeeeee SLAY
(Endocrine Pathology - Examples)
What is the term for adrenal cortical hypofunction?
Hypoadrenocorticism - addisons disease
What is hypoadrenocorticism caused by?
Adrenal cortical atrophy
What age and sex of dogs does hypoadrenocorticism affect? and what is the exception to this?
Typically young to middle-aged dogs, slightly more common in females, apart from breeds with a genetic predisposition
(eg Portuguese water dogs, bearded collies and standard poodles)
What is the most common cause of hyperadrenocorticism?
Functional neoplasms withing the adrenal cortex (adenomas, Adenocarcinomas)
T/F hyperadrenocorticism is another cause of cushings syndrome?
True
What are the three forms of Cushing’s Syndrome?
- Pituitary dependent (secondary hyperadrenocorticism)
- Adrenocortical dependent (primary hyperadrenocorticism)
- Iatrogenic
What is required to differentiate between the three forms of Cushing’s Syndrome?
Advanced serum biochemistry
T/F Adrenal medulla Hypofunction is common?
False - rare
What is Adrenal Medulla Hyperfunction associated with?
Functional neoplasia called pheochromocytoma
T/F Pheochromocytoma is usually non-functional?
True
If Pheochromocytoma is functional what can this cause?
- Catecholamine release
- Tachycardia
- Oedema
- Cardiac hypertrophy
What are possible causes of primary hypothyroidism?
- idiopathic follicular atrophy
- lymphocytic thyroiditis (immune-mediated)
What are the possible causes of secondary hypothyroidism? and what can this lead too?
Decreased TSH from pituitary disease which can lead too decreased basal metabolic rate, T3, T4 and increased cholesterol
Describe the metabolic findings of Hyperthyroidism in dogs?
- Lethargy
- Weight gain
- Exercise Intolerence
Describe the Dermalogical findings of Hyperthyroidism in dogs?
- Hair thinning
- Poor quality coat
- Hyperpigmentation
- Pyoderma
Describe the pathological findings of Primary Hyperthyroidism in dogs
Small, often pale thyroid
hyperk…
Describe the pathological findings of Secondary Hypothyroidism in dogs
Hyperkeratosis, Hyperpigmentation, Myxoedema and Atherosclerosis
myxoedema is advanced hyporthyroidism
Hypothyroidism and atherosclerosis
What is Goitre ad what is it caused by?
It is a special kind of thyroid dysfunction caused by:
- Iodine deficiency
- OR iodine toxicity
- OR goitrogenic plants
what does Goitre result in?
Inadequate T3/T4 synthesis
Thyroid hyperplasia
Lack of maternal dietary iodine in pregnancy
Hypothyroidism: Goitrogens
When do Goitrogens appear?
As a result of Hyperplastic Goitre
What drugs can be used to increase the breakdown if T3 and T4 in Goitre?
Phenobarbitone and rifampin
What is the cause the enzyme defect that leads to Dyshormogenesis?
Impaired thyroglobulin biosynthesis - which is the protein responsible for producing T3, T4 - leads to Dyshormogenesis which is a primary form of hypothyroidism
T/F In either primary or secondary Hyperthyroidism will manifest as increased T3/T4 levels
True
What will increased T3/T4 lead too?
- Increased metabolic rate
- Cardiac hypertrophy
- Sudden death
What are the 3 causes of Hypocalcaemia?
- decreased PTH conc
- Inadequate Ca2+
- Excess Urinary excretion of Ca2+
What are the three hyperfunctions of the parathyroids?
- Secondary Hyperparathyroidism
- Pseudohypoparathyroidism
- Primary Hyperparathyroidism
Describe what happens when renal secondary hyperparathyroidism is present?
- Decreased glomerular filtration rate
- Phosphate retention
- Continued stimulation of the para thyroid gland
- Continued resorption
What does this chronic renal disease lead too?
Fibrous osteodystrophy where bone is replaced by fibroblastic tissue, bone remodelling takes place, periosteal new bone formation sn results in bones that are soft, rubbery and easily fractured
Nutritional secondary hyperparathyroidism is when what?
There is a Dietary imbalance of calcium and phosphorus which could entail: Low Ca (or high oxalates), High P (and low or normal Ca), and Occasionally vitamin D deficiency overall leading to increased PTH production.
What is the name of the peptide that is produced with humoral hypercalcemia of malignancy? and what does this cause?
PTHrP which causes increased intestinal absorption, resorption from bone and decreased renal excreation of Ca overall leading to to hypercalceamia
What is the clinical syndrome that is pancreatic islet hypofunction?
Diabetes mellitus
What is diabetes mellitus caused by?
damage to the islets
what is often caused by islet hyperfuction?
beta cell - islet cell tumours
What does the increased insulin production cause?
Hypoglycemia can lead to a decreased bioavailability (neuro signs can be seen clinically) or can cause adrenal medulla to secrete catecholamines ( increased blood pressure)
(Trans genetics and cloning)
Molecular cloning is what?
Manipulation of Nucor acid
What does molecular cloning in bacteria allow for?
Amplification/expression of the changed DNA
What is the difference between transgenic and cloned animals?
transgenic is deliberate mod of the genome whereas as cloned is transfer of entire genome from one Individual to create another
T/F the rate of success in transgenic animals high
False - it is low
In transgenic animals, what must the transgene become established in to be passed on?
Gremline
What additions do transgenic animals have?
They can have additional DNS sequences or they can hVe a particular sequence deleted from/ inactivated in their genome
What can breeding from transgenic animals lead to in terms of the genetic alteration?
Breeding from transgenic animals can lead to lines in which the genetic alteration is present in all cells
Do what are the 3 elements that make up a transgene?
Contains a promoter, gene, and a poly A sequence
T/F the gene in the transgene construct to be expresses is clones downstream of promotor
True
What is the promotor used for in the transgene construct?
May be used to direct expression in all cells of the transgenic animal or used to direct expression to a particular tissue
What are the poly A sequence required for?
To guarantee efficient processing of the mRNA
What are the 4 technical approaches to make GN animal
- pro nuclear DNA micro injection
- Gene targeting of embryonic stem cells
- retroviral vectors
- gene editing
What are the 5 streps of pro nuclear micro injection?
- eggs are harvested aftertaste super ovulation and fertilised in vitro
- the fine needle injects transgene containing solution
- Embryos are implanted into a pseudo pregnancy foster mother who will birth the litter
- DNA from tail tissue samples is multiplied by PCR and analyser for presences of new DNA
- Mice showing optimism expression of the new gene are selected, the new DNA will be stabled in further generations
What are the advantages of pro nuclear micro injection?
- Simple technique
- Direct injection DNA solution into fertilised embryos
- Embryos at 1-cell stage, but if integration after 1-2 cell divisions possibility of mosaic
- Capable of germ line transmission
- Large DNA constructs
What are the disadvantages of pro nuclear micro injections?
- Random integration at low efficiency
- more than one copy integrates
- only 10 to 40 percent of viable offspring are transgenic
- Chromosomal site integration can result in effects on transgene expression
Describe embryonic cell transfer
- targeted gene alteration made to ember upon stem cell cukture
- the mutated stem cell is injected into blastocyst driver crook a fertiliser mouse egg
- the blastocyst is then implanted into the foster mother who will give birth
What are the adavantages of embryonic stem cell transfer?
- targeting to specific insertion point possible
- can check location/expression trangene In vitro
- Can be used to derive knockout animals
- Can be stored indefinitely
what are disadvantages of embryonic stem cell transfer?
Embryos at multicell stage (-> mosaics)
What stage is retroviral vectors carried out at and what does this mean for animal?
In multicellular stage so mosiac - not all cells carry intergrated transgene
T/F retroviral vectors give efficient transfer of a single copy of the trangene at a single randome chromosomal site?
True babes
What are the pros of transgenics
Specificity: The characteristic required can be targeted
Speed: Characteristic potentially acquired in few generations
Flexibility: Cross species possible e.g. human gene in mouse
What are the cons of trangenics
Animal health: Insertion of transgene may upset genome expression
Potential risk to environment: An escaped (laboratory) transgenic animal could pass transgene into wild populations
what are the 4 examples of trnasgenics?
- molecular pharming
- Xenotransplatation
- improved production
- targeting disease vectors
what is molecular pharming?
developing new or improved biologics and theraputic agents
Describe the how Trangenic is seen in livestock?
The transgene is usually directed for expression of milk, this milk can be harvested and from the milk the trangenic protein can be purified which can be administered to target species ie us lol
what is xenotransplanation?
The transplantation of an organ, tissue or cells from one species to another
describe reproductive cloning
1.A donor cell is taken from a sheep udder and an egg cell from an adult female sheep of which the nucleus is removed
2.These two cells are fused using electric shock
3.The fused cell begins dividing normally
4.The embryo is placed in the uterus of a foster mother
5.The embryo develops normally into a lamb- dolly
what are concerns regarding cloning?
Only 1 out of 277 attempts succeeded when making Dolly
Efficiency generally <5%
Short lifespan of clones (Dolly died at 6)
Epigenetics, x-chromosome inactivation, environmental factors – differences clone vs ‘parent’
Ethics
what is stem cell threapy?
Use of stem cells to alleviate disease in animals and humans
Describe embryonic stem cells
- pluripotent potential
- divide with limitless potential
- grow in undofferentaited states in culture
- can contribute to all somatic tissue and germ cells when reintroduced into embryo
what are issues with embryonic stem cells?
- Human Somatic Cell Nuclear Transfer requires human eggs
- Potential of creating a human reproductive clone if blastocyst implanted. Solution: UK law that cloned embryos cannot be kept >14 days
- Cost & Inefficiency
- Transmission of animal viruses- Stem cells are cultured in products that may contain animal products & successful culture is on murine feeder layers
- MORAL & ETHICIAL CONCERNS outweigh all other considerations
what is the solition to these issues?
non-embryonic stem cells
Describe tissue stem cells
- potential to differnetitate into many
- multipotent
(neoplasia - Diagnosis and staging)
Describe a superficial mass
- can appear fair;y small and innocuous
- can look large and obvious
- Lesion may loon ulcerated or inflammatory rather thatn a solid mass
What is a direct physical effect tumours can have?
non-specific clinical signs that are due to hidden internal tumour
eg. tumour in nose - blocks breathing
What is a indirect tumour effect?
This is where the tumour can cause other medical clinical signs
eg. tumour in adrenal gland cause issues with cortisol production
Describe the standard approach a lump?
- is it cancer?
- How extensive is it?
What are the 3 differentials to consider when making a diagnosis?
- is it neoplastic or is it reactive/inflammatory/developmental?
- What type of tumour is it? like which organ and cell types, rimary or metastasis
- How aggressive is it? how will it behave?
What would you take a biobsy for?
Histopathology via taking a piece of tisse and fix it in formalin
Why would you take a fine needle aspirate for?
Cytology via sucking out a reptesentative population of cells and air dry/fix
What can a Biopsy tell us
- Info on cell type and architecture
- How tumour interacts with surrounding tissues
- cell prification criteria for predicting tumour behaviour
What are some negatives of taking a biopsy?
- sedation needed
- more expensive
- time consuming
Describe the grading schemes for a sarcoma (CT tumour)
high grade - needs agressive treatment and chemo
Low grade - local surgery usually sufficient
intermediate grade - local treatment +/- chemo
Describe the grading schemes for a mast cell tumours
High grade - needs agressive treatment and chemo
Low grade - local surgery should be enough
Descibe the difference between incisional and excisional biopsy
- Incisional (wedge)
- excisional (whole mass)
What can fine neoplastic aspirates tell us?
If its inflammatory or neoplastic
Lineage - sarcoma. carcinoma, lymphoid, cast cell
What are the down falls of fine needle aspirates?
- No tisue architecture so only examine cells in isoloation
- can be unrepresentative
Describe the fine nnedle aspirate method?
- Suck out cells from mass
- Expel onto glass slide
- Smear the aspirate
- Stain and examine under microscope with diff-quick stain
What does TMN system stand for?
locally
T - Primary Tumour
Distant sites
N - Lymph node
M - Metastasis
What does TMN staging provide?
The anatomical extent of the tumour
Describe the investigation of primary tumour (T)
- Diagnosis - primary/metastasis? cell type? grade?
- staging - size/ attached or not? invasion? multiple lesions?
- For treatment measure uts dimensions and asses whether there is local invasion
T/F for a primary naso-maxillary tumour CT might be required?
True - to establish local extent for staging and to decide if surgery/XRT possible
What is a sential node?
first nodes to drain a tumour area i.e. at most risk for metastasis of migrating tumour cells
Why are sentinel nodes important?
Clinical decision making depends on whether they are infiltrated by tumour cells
Positive sentinel node means?
You need to remove this node and treat more aggressively
Negative sentinel node means?
Unlikely to have spread to LNs beyond this so less aggressive therapy needed
What are the 4 ways mastastases can spres?
Lymphatic (carcinomas, mast cell tumours)
Haematogenous (sarcomas)
Direct extension along tissue planes
Seeding across Thoracic/Peritoneal cavity
Why would you do a physical examination with mastastases?
For external mets like skin lesions
(Neoplasia: treatment options- surgery, radiotherapy and immunotherapy )
What is the new approach to cancer?
An informed and carefully planned treatment regime (multimodality) to achieve:
- Good quality of life
- Prolonged survival (palliative)
- Cure (definitive)
- Euthanasia (Cancer too advanced, Concurrent disease, Financial reasons)
What are local treatments of cancer/
surgery or radiotherapt
What are systemic treatments of cancer?
This is where you comine local and/or sytemic treatments
- Chemo or immunotherapy
When treating primary tumours should you consider stage?
Yes - circumscribed and easily reseceted or is it inflitrative and needing radical surgery
What are the treatment options for priary tumours?
- surgical
- radiotherapy alone
- combined
What is the treatment options or Lymphnodes?
- Surgical excision of node
- Radiotherapy of node
- [Chemotherapy if node is positive /high grade disease]
What are the tw parts for a good oncological surgery technique?
- Tumour excision
* the best CURE for locally confined tumours
* First attempt has best chance of success (CURE)
* Poorly planned surgery results in inadequate removal and tumour recurrence - Wound reconstruction
* Various techniques possible
What does cytoreductive mean?
This is where you debulk during srgery and then radio/chemo after
what are the 4 surgical techniques when doing a definitive insision?
- marginal excision - narrow wargin od 1-2mm
- local excision - remove up to 1cm margin
- Wide Local excision - wider margin 2-3cm
- Radial local excision - all tissue away
What kind of tumour would you do a loacl excision on?
Benign/non-invasive tumourW
what kind of tumourwould you use wide local excision on?
malignant tumours
What type of tumours would you use radical local tumours?
- large, infiltrated tumours
- recurrent tumours
what does Incomplete margins mean
tumour extending to margin of excision/scalpel cut when viewed down a microscope
what are complete margins
clear boundary of normal tissue before scalpel cut.
what are the reconstructive techniques used aftertumout removal?
Advancement flaps
Free skin grafts
Meshing techniques
