Issues in Healthcare (Not including 21st century babies)

What is embryology and what does it cover?

"- the branch of biology concerned with the development of organisms.

•Embryonic development in the human, covers the first eight weeks of development after fertilization; at the beginning of the ninth week the embryo is termed a fetus.

•The normal period of gestation (pregnancy) is about nine months or 40 weeks.

"

What are the stages of embryonic and fetal development?

Week 1 : Fertilisation to implantation

Week 2: Bilaminar Germ disc + Amniotic cavity and Primary yolk sac

Week 3: Gastrulation:

- trilaminar germ disc - cell differentiation, flat disk of 3 layers

- primitive streak

- notochord

- neural tube

- body axes/ growth of embryonic disc

Week 3-8: Organogenesis (embryonic period):

- neurulation

- development of Somites

- development of intraembryonic coelom

- development of primitive cardiovascular system

- development of all major organ systems

Week 8 - Birth: Fetal Period

- Maturation tissues and organs

- rapid growth of the fetal body

Birth - Adult: Post Natal

- growth and development

What are the stages of the postnatal period?

"

•Infancy – approx. first year post birth

•Childhood – period between infancy and puberty

•Puberty – between 8-13 years of age functionally capable of procreation

•Adulthood – between the age of 18 - 21

"

What happens in Fertilization to implantation in week 1?

"The sperm and egg join, and their genetic material (pronuclei) fuse to form a zygote.

The zygote divides into 2 cells, then continues dividing (cleavage) until it becomes a solid ball of cells called a morula.

The morula becomes a blastocyst, a hollow structure with two main parts:

Inner cell mass (embryoblast) – will become the embryo.

Outer cell mass (trophoblast) – will become part of the placenta.

The blastocyst then attaches to and starts to implant into the wall of the uterus. (Diagram shows zygote → morula → blastocyst → implantation into uterine wall)

"

What happens in the development of the Bilaminar Germ Disc in Week 2?

"

The inner cell mass splits into two layers:

Epiblast – tall cells that will form the embryo (high columnar cell).

Hypoblast – smaller cells beneath the epiblast (cuboidal cell).

Amniotic cavity and the primary yolk sac are formed.

The chorionic cavity and the chorionic plate are formed

Early blood vessels start to form, beginning the uteroplacental circulation (connection to the mother’s blood supply).

The connecting stalk (which becomes the umbilical cord) and secondary yolk sac are formed. (Diagram shows bilaminar disc with epiblast, hypoblast, amniotic cavity, yolk sac)

"

What happens in the formation of the trilaminar disc?

"

Just remember each of these layers go on to form different things

Formation of three cell layers:

◦Ectoderm: Nervous system, epidermis, hair and nails, enamel of teeth, sensory epithelium, eye, ear and nose

◦Mesoderm - can differentiate to 3 types - paraxial mesoderm, intermediate mesoderm, lateral mesoderm: lining of body cavity, muscle, connective tissue, bone, blood and blood vessels

◦Endoderm: linings of digestive and respiratory tracts

(Diagram shows three germ layers: ectoderm (outer), mesoderm (middle), endoderm (inner))

"

What happens in organogenesis weeks 3-8

"

Trilaminar germ disc folds and the cells differentiate into specific tissues and organs

◦Early development of all major organ systems

◦Neurulation – central nervous system development

◦Development of intraembryonic coelom (body cavity)

◦Development of primitive cardiovascular system

◦Development of Somites and the Musculoskeletal system

◦Development of the Digestive, Respiratory, Urogenital and other body systems

(Diagram shows developing embryo with neural tube, somites, heart prominence, and limb buds)

"

What happens in embryo folding weeks 4-8 (the two types of folding)?

"

Longitudinal (puts the organ systems into the right places) and transverse folding (forms the tubes) converts the flat trilaminar embryonic disc into a C-shaped, cylindrical embryo

Transverse folding: Lateral edges fold inward, forming a tube (gut tube) and bringing the body walls together.

Longitudinal folding: Head and tail folds develop, moving the heart and other organs into position and creating the C-shape.

"

What are the embryonic cavities?

Visceral - forms wall of primitive gut

Parietal - forms body wall

Fetal circulation?

"- There are bypass shunts in fetal circulation: ductus venosus (liver bypass), foramen ovale (atrial septal opening), ductus arteriosus (pulmonary artery to aorta bypass) — these allow blood to skip the non-functioning fetal lungs."

What type of layer is involved in the musculoskeletal system?

• mainly mesodermal when it comes to development of musculoskeletal system

What happens in limb development?

"- Onset of development of arm bud - 27 days

- Full separation of fingers - 50-52 days

- Limb buds form from mesenchyme, then elongate and differentiate into humerus, radius/ulna, then digits; apoptosis separates fingers.

"

What is epigenetics?

Epigenetics is how genes are turned on or off without changing the actual DNA.

- switching on and off genes

- reversible

-In sperm and egg cells (gametes), epigenetic marks are reset

Why is epigenetics important?

"

•Mechanism to control global patterns of expression

•New therapies and diagnostics

•Future of precision medicine

•Understanding biology underpinning disease

•Maximizing value from genome data: EPIGENOME

"

What are the mechanics of epigenetics (nucleosomes,euchromatin,heterochromatin)?

"

- DNA wraps around proteins called histones to form nucleosomes 

- Changes (modifications) to the DNA or histone tails can control how tightly the DNA is packed.

•Euchromatin is loose and open, so genes can be read and switched on and template for transcription

•Heterochromatin is tightly packed and closed, so genes are switched off.

•EPIGENETIC mechanisms control euchromatin/heterochromatin transition (Diagram shows DNA wound around histones; loose = active, tight = inactive)

"

What are the 4 main epigenetics mechanisms?

"

1.DNA modification

2.Histone modification

3.Remodelling complexes

4.Non coding RNA (ncRNA)

"

What happens in DNA methylation?

"DNA methylation condenses (addition of methyl groups) promoter (acts like a switch) regions, making them less accessible and leading to gene silencing (can’t be turned on).

It changes the affinity of transcription factors(proteins), meaning they can no longer easily bind to the DNA.

It recruits methyl-DNA binding proteins, which help maintain the gene in a silent state.

It also alters nucleosome structure, making the DNA more tightly packed and harder to transcribe.

DNA methylation is like putting a lock on the gene’s control switch. (Diagram shows methyl groups (CH3) attached to CpG islands in promoter region, blocking transcription factors)

It blocks the tools (transcription factors) from getting in, calls in helpers to keep it shut, and tightens the whole area, so the gene stays off

"

Is DNMT a therapeutic target?

DNA Methyl Transferases (DNMTs) are the enzymes that add methyl groups. 

When tumour suppressor genes are switched off by too much methylation, cancer cells can grow faster.

If we inhibit DNMTs, we can reduce this extra methylation (hypermethylation) and help turn tumour suppressor genes back on.

So, targeting DNMTs could help slow down or stop cancer growth.

How good of a drug is DNMT?

- Drugs that block DNMT can reverse methylation, but the effects can be non-specific — they might affect genes we don’t want to change.

- At high doses, these drugs can be toxic to cells - cytotoxic.

- Patients may not tolerate these drugs well if they’re also getting chemotherapy — it can be too harsh on the body.

What are the mechanics of histone modification (active + passive mechanism)?

"Passive Mechanism

- Histone acetylation adds acetyl groups(neutral) to histone tails(+).

- This neutralises positive charges, so DNA (which is negative) loosens its grip on histones.

Result: Chromatin opens up, making genes easier to read.

Active Mechanism

- Certain histone marks recruit chromatin remodellers—special proteins that use ATP (energy) to slide or restructure nucleosomes.

This actively changes how DNA is wrapped, either opening or closing regions.

Both types are REVERSIBLE processes. Histone modification can open and close chromatin

"

What are some impacts of inhibitors of histone deacetylases?

- HDAC inhibitors restore histone acetylation (stop enzymes that remove acetyl groups from histones).

- This helps keep chromatin open, so tumour suppressor genes can be switched back on.

- This can slow down cancer growth.

- But they can also affect other genes, causing side effects.

- Scientists are working on more targeted drugs to make treatment safer and more specific.

What is chromatin remodelling?

"

REMODELLING is the rearrangement of nucleosomes to a transcriptionally active state

Performed by complex enzyme machineries - group of enzymes like machines

Recruited by interactions with DNA & histone modifications: CROSSTALK (Diagram shows ATP-dependent remodelling complex sliding nucleosome along DNA to expose promoter region)

"

What happens when you disrupt remodelling complexes?

"

Frequent mutations in cancer & neurological disorders

Potential biomarkers for diagnostics

Also, for prognosis- predicting the likely outcome

New therapeutic targets identified

Impact numerous signalling oncogenic (tumors) pathways

"

What are the mechanics of non - coding RNA (ncRNA)

Some RNAs don’t make proteins — they have other jobs, like controlling gene activity.

One type, called microRNA (miRNA), is a short, double-stranded RNA.

It’s cut by an enzyme called Dicer into smaller pieces (~23 base pairs).

One strand is used by a complex called RISC, which helps block or destroy mRNA.

This stops the mRNA from making a protein — like turning a gene off.

These RNAs can also guide changes to DNA that affect epigenetics.

They play big roles in cancer and other diseases, and are useful in diagnosis and treatment (theranostics).

How good of a drug are siRNA’s(short, double-stranded RNA molecules that silence specific genes.)?

✅ Good Things:

- Scientists can find siRNA that targets specific disease genes and test them in the lab.

- siRNAs can be combined with other drugs to improve treatment.

❌ Bad Things:

- siRNA is easily broken down in the body and hard to deliver into cells.

- If the target mRNA mutates, siRNA might not work — the cell can become resistant.

What are teratogens?

"

A teratogen is any substance, agent, or factor that causes malformations or abnormalities in a developing embryo or foetus when a pregnant woman is exposed to it. (Diagram shows examples: alcohol, thalidomide, rubella virus, radiation, certain drugs)

"

Is there a future of epigenetics medicines, consider the advantages and disadvantages?

"Advantages: reversible, target specific genes, new therapies for cancer and neurological disorders. Disadvantages: off-target effects, delivery challenges, long-term safety unknown."

What is a pathogen?

 A pathogen is defined as an organism causing disease to its host, with the severity of the disease symptoms referred to as virulence. 

What are some examples of microbiological pathogens ?

1. Bacteria - mycobacterium tuberculosis
   2. Viruses - chickenpox
   3. Fungi - vaginal thrush
   4. Protozoa - malaria

Describe the structure of bacteria

"

Bacteria have: cell wall (peptidoglycan), cell membrane, cytoplasm, ribosomes, nucleoid (DNA), sometimes capsule, pili, flagella. Shapes: coccus (spherical), bacillus (rod), vibrio (comma/curved rod), spirochaete (spiral). (Diagram shows typical bacterial cell with labelled structures)

"

What are the 4 steps for Gram staining?

"

Using a smear slide

1. Stain with crystal violet

2. Stain with Gram’s iodine

3. Decolorise with acetone

4. Counter stain with safranin

"

What’s the difference between Gram + and Gram - bacteria(3)? (Remember positive peptidoglycan)

"Gram-positive: thick peptidoglycan layer, stains purple, retains crystal violet, no outer membrane, more sensitive to penicillin. Gram-negative: thin peptidoglycan layer, stains pink, has outer membrane with lipopolysaccharide (LPS), more resistant to antibiotics."

What features do we use to classify bacteria?

"

•Staining

•Shape

•Respiration

•Reproduction

•Genus

•Species

"

What are Koch’s 4 postulates to establish a relationship between a microbe and a disease?

"

1.The microorganism must be found in abundance in all organisms suffering from the disease

2.The microorganism must be isolated from a diseased organism and grown in pure culture.

3.The cultured microorganisms should cause disease when introduced into a healthy organism.

4.The microorganisms must be re isolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent (Diagram shows flow: sick animal → isolate microbe → grow pure culture → inject healthy animal → animal gets sick → re-isolate same microbe)

"

How do you investigate bacteria in the laboratory?

"

•Sample – blood, tissue, faeces,

•Culture – plates, liquid, within live animals, use of vector

•Microscopy – use of stains

•Biochemical tests – looking at metabolic processes specific to the bacterium

•Molecular tests – PCR and DNA sequencing

"

What used to be used to treat bacterial infections in the past?

"

•Arsenic

•Bromine

•Mercury

•Honey

"

What do we currently use to treat bacterial infections?

antibiotics - slow down the growth of bacteria

What is epidemiology?

Epidemiology is the study of how diseases spread, their causes, and the factors that influence their distribution in populations. 

What does epidemiology tell us?

"

•Study the frequency of disease

•Examine and explain patterns and trends in where, when & for whom disease occurs

•Tells us which groups are at greater risk

•Provides basis for developing disease/poor health prevention and control measures

•Can be used to make predictions and to measure change

"

What is prevalence and describe the 2 types?

Prevalence = the total number of cases of a specific disease or health condition that exist in a particular population at a given point in time or over a specific time period. 

Point prevalence = The proportion of individuals in a population who have a particular disease or condition at a specific point in time. E.g. (how many ppl have it rn)

Period prevalence = number of cases of diseases during time period/ population size during time period. E.g. (how many ppl had it at some point during this time)

What is the definition of incidence?

incidence refers to the number of new cases of a disease or health condition that develop in a specific population during a defined period of time. 

It focuses on how quickly new cases are occurring and helps measure the risk of developing the disease in that population.

What are the 2 types of incidence?

Incidence rate = measures how rapidly new cases are occurring, considering the time at risk.

Cumulative incidence = the proportion of a population that develops the disease over a specified time period. 

What is the difference between incidence and prevalence?

Incidence is about new cases; Prevalence is about total cases.

What is an epidemic?

• a sudden increase in the number of cases of a disease, often in a specific region or community, over a short period. 
  - a serious outbreak in a single community, population or region

What is an outbreak?

• a sudden increase in occurrences of a disease

What is an endemic?

• the habitual presence of a disease within a given geographical area
  - the constant presence or steady occurrence of a disease or health condition within a specific geographic area or population.

What are forgotten diseases?

Forgotten diseases = Neglected Tropical Diseases: 

- diverse group of tropical infections

-  common in low-income populations in developing regions in Africa, Asia and America 

- cause substantial morbidity and mortality in > 1 billion people 

- trap the poor in a cycle of poverty and disease

What is an emerging disease?

"

Due to a pathogen not observed within a population or geographical location before.

"

What is a reemerging disease?

caused by a known pathogen that shows up in a new geographical area or was once under control but starts spreading again or increasing in cases.

What is a zoonotic disease?

Infectious disease of animals that is transmitted to humans.

What is Disease X?

"“Disease X"" is a term used by the World Health Organization (WHO) to describe an unknown, hypothetical infectious disease that could cause a future epidemic or pandemic."

What is monkeypox?

• an emerging zoonotic disease
  - caused by the monkeypox virus
  - found in parts of Central and West Africa
  - transmitted to humans through contact with infected animals, like rodents and primates.
  - Symptoms: fever, headache, muscle aches, and swollen lymph nodes, rashes,  blisters

Why is monkeypox an emerging disease?

• since 2022, outbreaks have occurred in multiple non-endemic countries, including those in Europe and North America.
  Increased Travel and Globalization: Movement of people between regions has allowed the virus to spread beyond its traditional locations.
  Decreasing Immunity to Smallpox: The end of smallpox vaccinations has led to lower immunity against related viruses like monkeypox in populations globally.Monkeypox is similar to smallpox. In the past, people got vaccinated against smallpox, and that also protected them from monkeypox
  Changing Human and Animal Interactions: Factors like urbanization and deforestation may increase contact between animals and humans.

 Explain the impact of a newly emerging disease on health, society and the economy.

Health: 

- The disease can cause high illness and death rates, which can overwhelm hospitals. 

- It also impacts mental health due to fear and stress, especially among healthcare workers.

Society: 

- People may avoid public places due to fear, leading to social isolation. Schools and public services may close, disrupting daily life and increasing inequality in affected communities.

Economy: 

- Many people can't work due to illness or lockdowns, reducing productivity. 

- Trade and supply chains are disrupted, causing shortages of essential goods. 

- Governments may have to spend more on healthcare, potentially leading to economic recession due to reduced consumer spending and investment.

What is spillover?

Spillover refers to the process by which pathogens, such as viruses or bacteria, transfer from one species to another, particularly from animals to humans. 

What are examples of recent zoonotic disease outbreaks?

COVID-19 (SARS-CoV-2)

Origin: Believed to have originated in bats and possibly transmitted to humans through an intermediate animal, potentially in a wet market in Wuhan, China.

Outbreak: First identified in December 2019, it quickly spread globally, leading to a pandemic. It has caused millions of infections and deaths.

Impact: Severe health, social, and economic consequences, prompting lockdowns, travel restrictions, and the rapid development of vaccines to control the spread of the virus.

Ebola Virus

Origin: Thought to be transmitted from fruit bats to humans, with human-to-human transmission occurring through contact with bodily fluids of infected individuals.

Outbreaks: The most notable outbreak was in West Africa from 2014 to 2016, with thousands of deaths. Smaller outbreaks continue to occur in the Democratic Republic of the Congo.

Impact: High fatality rates and significant strain on healthcare systems in affected areas. Public health responses have included extensive monitoring, community education, and vaccination efforts to prevent future outbreaks

What is avian influenza, include the types, transmission, symptoms, public health concerns, prevention + economic impact?

A viral infection affecting birds, primarily caused by H5N1 and H7N9 strains.

Types:

- Low Pathogenic (LPAI): Mild illness in birds.

- Highly Pathogenic (HPAI): Severe disease and high mortality rates in birds.

Transmission: Spreads through direct contact with infected birds, their droppings, or contaminated environments.

Symptoms:

- In Birds: Sudden death, respiratory distress, and reduced egg production.

- In Humans: Fever, cough, and severe respiratory issues, though infections are rare.

Public Health Concerns: HPAI strains can infect humans, leading to severe illness. Monitoring is essential to prevent outbreaks.

Prevention: Includes bird population monitoring, poultry vaccination, biosecurity measures, and public education.

Economic Impact: Outbreaks can cause significant losses in the poultry industry due to production declines and trade restrictions.

Describe the history of smallpox?

"

Smallpox

●millions of smallpox cases every year until the 1970s.

●in the century prior to eradication there were 500 million deaths

Variolation - Deliberate exposure to smallpox to induce a mild infection and immunity:

●First documented use in China and India in the 10th century

●Very popular across the globe by the 18th century

Inoculation - Introduction of an antigen to trigger an immune response:

●Edward Jenner used the Cow Pox pathogen to inoculate against smallpox in the 18th century

Vaccination

●Jenner’s work was the start of modern immunisation techniques using vaccination

●Smallpox was eradicated globally by the 1980s

"

Describe the history of Polio.

"

Isolation

●First described in the UK in 1789

●Isolated in 1949 in the Boston Childrens Hospital

Vaccine

●Joseph Salk created an inactivated virus vaccine in 1950

●He tested on himself and his family in 1953

●1.6 million children were vaccinated in 1954

●Inactivated Polio Vaccine (IPV) was licensed in 1955

Impact

●By 1957, reported annual cases dropped from 58 000 to 5600, and by 1961, to 161

"

What are HeLa cells and the ethical implications of them?

"

HeLa Cells

●Developed from the cervical tumour of Henrietta Lacks in 1951

●The cells are used in laboratories across the world and their positive impact on health and research is hard to overestimate

●No permission or consent was granted by Henrietta Lacks or her family

●No compensation or benefit has been made to her family

Ethical implications

●Autonomy

●Privacy

"

Describe the action and function of a vaccine?

"

Vaccines

●A vaccine contains biological material resembling a pathogen

●Often inactive or weakened pathogens, toxins or antigenic material from the pathogen

●Vaccinations provide acquired immunity

Action

●Stimulation of an immune response

●Resulting in antibody production and immunological memory

"

What are the 5 types of vaccines?

"

1.Live-attenuated

●Weakened live forms of the pathogen e.g. measles, mumps and rubella

2.Inactivated

●‘Dead’ pathogens e. g. polio vaccine

3.Subunit, polysaccharide, polypeptide or conjugate

●Using antigenic material e.g hepatitis B

4.Toxoid

●Using inactive toxin e.g. tetanus, diptheria

5.mRNA

●Using viral mRNA e.g. Covid

"

What are the benefits of a vaccine?

"

Protection from disease

●Reduced severity of illness

●Herd immunity

●If 70-90% of the population is vaccinated, the spread of disease is limited

●This protects those unvaccinated (due to age or health status)

●Economic and Public Health impact

●Immunisation programmes reduce healthcare costs associated with treatment, hospitalisation and resultant disability

●Improved global health security

"

What are the risks (side effects) of vaccinations?

"

Common / mild

●Swelling, fever

●Uncommon / moderate

●Allergic response 1 in 1 million for MMR vaccines

●Seizure 1 in 3-4 thousand for MMR vaccines

●Rare / serious

●Myocarditis and pericarditis 1 per hundred thousand for mRNA COVID vaccines (usually in young men)

●Thrombosis less than 1 per million for COVID vaccines (usually in young women)

●Long term effects

●Frequently discussed but investigations into suggested links have shown no evidence (e.g. into link between HPV vaccines and rheumatoid arthritis)

"

What are the challenges and ethical issues of vaccinations?

"

●Parental consent

●How much autonomy should parents have when public health is at risk?

●Should vaccination be mandatory for enrolment in schools?

●Vaccine hesitancy

●Concerns over safety, mistrust in industry and government contribute to parental refusal or delay

●This compromises herd immunity leading to outbreaks and deaths

●Side effects and risks

●These do exist but are most often outweighed by the risk of the disease

●How can this be communicated?

●Distribution

●There are often inequalities in vaccine distribution between the Global North and Global South.

"

Describe HIV/AIDS in relation to the role of vaccinations.

"

●HIV was confirmed as the cause of AIDS in 1984

●It is now a global health challenge with ~ 38 million people living with HIV worldwide.

●A vaccine was ‘promised’ within two years, but there is still no effective HIV vaccine.

●What makes it so difficult -

●HIV is latent (hide in body but still spread) but infectious for long periods - vaccines protect against active disease

●Most people don’t recover from AIDS, so there’s no natural immune response for scientists to copy.

- We can’t use a weakened (attenuated) or killed version of HIV in a vaccine because it doesn’t trigger a strong enough immune response.

- HIV mutates very quickly, creating lots of different versions — this makes it hard to target.

- There is already effective treatment (ART), so the urgency for a vaccine is reduced, but it’s still needed.

"

Describe COVID-19 in relation to the role of vaccinations in healthcare.

"

●The fifth-deadliest pandemic / epidemic in history

●More that 7 million confirmed deaths worldwide to date.

●A vaccine was developed in less than 1 year

●Researchers built on new technologies including mRNA vaccines

●Academics and industries worked together with the support of government agencies

●Equity

●The vaccine rollout faced challenges with vaccine hesitancy, misinformation and unequal global distribution which continue

"

What is the MMR controversy?

"

●The MMR vaccine protects against mumps, measles and rubella

●Measles

●In 2022 it was estimated there were over 130 000 deaths due to measles (WHO)

●Deaths are mainly in unvaccinated / under vaccinated children of under 5 years old

●Vaccination is thought to have averted 57 million measles deaths between 2000 and 2022 (WHO)

●Andrew Wakefield published a now discredited paper in The Lancet in 1998

●This suggested a possible link between the MMR vaccine and autism

●The research was flawed, violated ethics and used manipulated data

●Subsequent studies have prove that there is no link between the MMR vaccine and autism

"

What is the impact of the MMR controversy?

"

●There is ongoing controversy particularly in the UK and the US

●There are lower vaccination rates in many countries

●The proportion of children receiving a first dose of measles vaccine was 83% in 2023, below the 2019 level of 86% and below the level required for herd immunity

"

What could be the future of vaccinations in relation to healthcare?

"

Public education - clear, transparent, science-based explanations addressing concerns

●Community engagement - tailored messaging delivered by trusted members of the community.

●Reducing barriers to access - travel, cost, convenience

●Policy - mandates, incentives

●Peer influence - highlighting uptake rates, and promoting social norms

●Digital tools - reminders and digital health records

"

What are environmental health practitioners and their goal?

"- they ensure that all the physical environments in which we work, eat, live + play are safe

- goal - to protect human health by minimising risks + eliminating dangers, in the natural and built environments

"

Where do EHPs work?

they work in all sizes + types of businesses all over the world including local authorities, government departments, the NHS , armed services + more.

What are the skills needed for EHPs?

problem solving, working in partnership with others to seek holistic solutions, effective communication

What are the disciplines of environmental health?

• environmental protection
  - public health
  - food safety + integrity
  - Health + safety
  - housing + communities

What do EHPs do in response to environmental protection?

• co ordinate responses to natural + man made disasters + assess contamination of sites proposed for new development 
  - also monito air,water,land + noise pollution

What do EHPs do when it comes to to land use?

• investigate brownfield + contaminated land sites, assess potential risks to human health, make sure appropiate works are carried out to remove the risk 

Define a pathogen and how they cause disease in humans.

An organism that causes disease to its host

To cause disease in humans, a pathogen must be able to bind to specific receptors on the human host cell.

What are the 6 pathogens and underline those that are microbiological?

Bacteria

Viruses

Fungi

Protozoa

Helminths

Prions

What is an example of bacteria?

Mycobacterium tuberculosis - tuberculosis

What is an example of a virus?

varicella-Zoster virus (VZV) - chickenpox

What is an example of fungi?

Candida albicans - vaginal thrush 

What is an example of a protozoa?

Plasmodium species - Malaria

What is an example of Helminths?

Flatworms - tapeworm

What is an example of Prions?

Creutzfeldt Jakob Disease

What is the structure of bacteria?

"Bacterial structure: cell wall (peptidoglycan), plasma membrane, cytoplasm, ribosomes, nucleoid (DNA), capsule (some), pili, flagella. Diagram shows labelled cross-section."

What are the different forms of bacteria?

"Cocci (spherical), Bacilli (rod-shaped), Vibrios (comma-shaped), Spirochetes (tightly coiled spirals). (Diagram shows the four shapes)"

How do you carry out gram staining using a smear slide?

1. Stain with crystal violet
   2. Stain with Gram’s iodine
   3. Decolourise with acetone
   4. Counter stain with safranin

What is the difference between Gram + and Gram - bacteria?

"Gram-positive: thick peptidoglycan, stains purple, no outer membrane. Gram-negative: thin peptidoglycan, outer membrane with LPS, stains pink. (Diagrams compare cell wall structures)"

What materials can prevent movement of substances through the cell wall and uptake of the gram staining?

fatty acids

What staining method is used to visualise cells under a microscope?

the Ziehl-Neelsen staining method

What are the 6 features used to classify bacteria?

1. Staining
   2. Shape
   3. Respiration
   4. Reproduction
   5. Genus
   6. Species

What are Koch’s 4 Postulates for a casual relationship between a microbe and a disease to be established?

1.Presence

The microbe must be found in all people (or animals) with the disease—but not in healthy ones.

2.Isolation

You must be able to grow (isolate) the microbe from the sick person in a lab.

3.Cause

When you put the microbe into a healthy host (animal), it should cause the same disease.

4.Re-isolation

You must be able to take the same microbe back out of the newly infected host and grow it again.

What 4 substances were used in the past to treat bacterial infections?

• arsenic
  - bromine
  - mercury
  - honey

What is used to treat bacterial infections in the present?

penicillin

What are B-lactams (target,mechanism of action, example,static/cidal, microbiological spectrum, administration, toxicology)?

Target - cell wall synthesis

Mechanism of Action - inhibit peptidoglycan synthesis by binding to PBPs(penicillin binding proteins)

Bactericidal (kill bacteria)

Gram+ AND Gram- 

You take them orally

They are safe + well tolerated

Example - penicillin

What are B-lactams 4 resistance mechanisms?

Permeability, Efflux, Inactivation, Target modification

What are glycopeptides (target,mechanism of action, example,static/cidal, microbiological spectrum, administration, toxicology)?

target - cell wall synthesis

mechanism of action - inhibits peptidogycan polymerization 

example - vancomycin 

static/cidal - bactericidal

microbiological spectrum - gram + only

administration - topical,oral, IV

toxicology - Can induce fatal anaphylaxis

What are polymyxins (cell membrane) (target,mechanism of action, example,static/cidal, microbiological spectrum, administration, toxicology)?

target - cell wall synthesis

mechanism of action - Binds to and disrupts lipopolysaccharide (LPS) in outer membrane of Gram-negative

pathogens, leading to cell lysis 

example - polymixin B

static/cidal - bactericidal 

microbiological spectrum - gram -

administration - topical,oral,IV

toxicology - nephrotoxicity + neurotoxicity

What makes a good therapeutic target for antibiotics?

Need a target not present in host cells to lessen TOXICITY

Bacterial target should be essential to decrease RESISTANCE

Level of conservation will determine microbiological SPECTRUM

What are the 4 D’s for antimicrobial stewardship?

Right Drug

Right Dose

Right Duration

De-escalation as soon as possible