Inflammation

Introduction

Inflammation is part of the complex biological reaction of the tissues of the body to harmful stimuli, such as bacteria, damaged cells or irritants, and is a defensive reaction involving immune cells, blood vessels and molecular mediators. 

Inflammation has the purpose of removing the initial cause of cell injury, clearing necrotic cells and damaged tissues from the initial insult and inflammatory process, and initiating tissue repair.

Inflammation is a generalized response, and thus, opposed to adaptive immunity, which is unique to each pathogen, it is regarded as a mechanism of innate immunity. Too little inflammation could cause the harmful stimulus (e.g. bacteria) to slowly kill tissue and threaten the organism’s survival.

There are two main types of inflammation:

1. Acute inflammation: It typically occurs for a short time (though sometimes severe). In two weeks or less, it generally resolves itself. Symptoms soon emerge of an injury or illness after acute inflammation is seen in the body.

2. Chronic inflammation: It is a slower form of inflammation and usually less severe. Usually, it lasts longer than 6 weeks. Even when there is no prominent disease, injury or illness, it can happen, and it doesn’t necessarily stop when the disease or injury is cured. Autoimmune conditions and even prolonged stress have been associated with chronic inflammation.

Inflammation symptoms

The five major signs that indicate the presence of inflammation are:

• heat
• pain
• redness
• swelling
• loss of function

Symptoms widely depend on the stage and condition that causes the inflammation in the body. Other symptoms that are observed in chronic inflammation include:

• body pain
• constant fatigue and insomnia
• depression, anxiety, and other mood disorders
• gastrointestinal issues, like constipation, diarrhea, and acid reflux
• weight gain
• frequent infections

Causes that lead to inflammation in the body

There are different factors which cause inflammation in the body. 

This include:

• Acute and chronic disorders 
• Some drugs 
• The body cannot quickly remove exposure to irritants or foreign materials. 

A chronic inflammatory response may also arise from repeated episodes of acute inflammation. 

In persons with autoimmune conditions, there are also certain forms of foods that can induce or exacerbate inflammation. 

These foods include:

• sugar
• refined carbohydrates
• alcohol
• processed meats
• trans fats

Treatment of Inflammation

There are a number of tests that can be carried out which show the presence of inflammation in the body. It can be as easy to combat inflammation as improving one’s diet.Inflammation is greatly subsided by eliminating sugar, trans fats, and processed foods. Some common anti-inflammatory foods are:

• berries and cherries
• fatty fish
• broccoli
• avocados
• green tea
• Tomatoes

Other remedies that can be practiced are:

• Consistently take required vitamins. 
• To decrease swelling and pain,  hot or cold treatment for physical wounds can be used.
• Exercise more often.
• Manage and lower the levels of stress. 
• Stop smoking. 
• Treat any preexisting conditions and control them.

Other treatment options:

NSAIDs and aspirin

In treating short-term pain and inflammation, non-steroidal anti-inflammatory drugs (NSAIDs) are typically the first line of protection. It is an over the counter drug.

NSAIDs that are popular include: 

• Aspirin
• ibuprofen (Advil, Motrin, Midol) 
• naproxen (Aleve)

Corticosteroids 

Corticosteroids are a form of steroid widely used to treat allergic reactions as well as swelling and inflammation. 

Typically, corticosteroids come as either a nasal spray or an oral pill. 

Article By- Ria Fazulbhoy (MSIWM031)

PATHOGEN PROFILE OF STREPTOCOCCUS PYOGENES

BY: SHAILY SHARMA (MSIWM041)

Streptococcus pyogenes (which is also called group A streptococcus) is by far one of the most harmful and serious streptococcal pathogens of humans. It is a strict pathogen that inhabits the throat, nasopharynx and occasionally even the skin in humans. 

Dissemination of the bacteria to other sites within the body causes a variety of severely invasive conditions which have an association with high morbidity and mortality.

When these streptococci are grown on blood agar, typically, small zones of beta-hemolysis of 2-3mm are seen.

Streptococcus pyogenes also demonstrate the ability of biofilm formation to communicate with other neighboring cells like other bacterial cells. The gene for biofilm formation controlled via quorum sensing.

Characteristics of the pathogen are:

• Microscopic Morphology: 

• It is a gram-positive coccus which is arranged in chains and pairs.
•  It is not usually motile and the occurrence of motility is considered rare.
•  It is non-spore-forming.

• Identification:

•  A catalase test is used to distinguish the Streptococcus (negative) from the Staphylococcus (positive).
•  The hallmarks of S. pyogenes include beta-hemolysis and sensitivity to bacitracin (antimicrobial agent).
•  A rapid way for identification is to use monoclonal antibodies that detect the C-carbohydrate found on the surface of the cell of S. pyogenes. 

• Habitat:

•  S. pyogenes is a fairly strict parasite which is found mainly in the throat, nasopharynx and occasionally in the skin of humans.
•  Most people (approximately 5% to 15%) are asymptomatic carries.

• Virulence factors: 

• The cell surface antigens present on S. pyogenes provide the virulence factors to the pathogen. 
• Some examples of such surface antigens are:

1. C-carbohydrate: It prevents the bacterium from getting dissolved in the lysozyme, which may be present in the throat and the nasopharynx, of the host.
2. Fimbriae: These are present on the outer surface of the cell. They are responsible for enhancing the adherence of the bacterium to the host cell.
3. M-protein: This protein helps in the resistance to phagocytosis and also improves the adherence of the pathogen to the host cells.
4. C5a protease: It is an enzyme that catalyzes the cleavage of the C5a protein of the complement system which prevents the hosts immune system from attacking the pathogen by disrupting the formation of the membrane attack complex (MAC).
5. Some strains of the bacterium have hyaluronic acid (HA) present on the surface which is identical to the HA found in host cells, this HA prevents the immune response by the host.
6. Streptolysin O (SLO) and Streptolysin S (SLS): They are two different type of hemolysins which damage the hosts leukocytes, heart and liver muscles.
7. Streptokinase, hyaluronidase, streptodornase: These are enzymes which aid in the invasion of the hosts body by digesting fibrin clots, connective tissues and DNA respectively.

• Primary infections/Disease: 

• It causes local cutaneous infections like impetigo (pyoderma) or erysipelas which is more invasive.
•  Streptococcal pharyngitis is caused by the infection of the tonsils and the pharyngeal mucous membranes (strep throat) which can lead to scarlet fever if left untreated. 
• The long-term complications of S. pyogenes are rheumatic fever and acute glomerulonephritis. 

• Control and treatment: 

• S. pyogenes can be controlled by limiting the contact between carries of the bacterium and immunocompromised hosts. 
• Isolation of patients must be done and care should be taken while handling the infectious secretions. 
• The treatment is usually a simple course of penicillin since the bacterium shows little drug resistance. 

S. pyogenes do have some applications in the field of bionanotechnology and genome editing as well. 

– In bionanotechnology; the proteins of S. pyogenes have some unique properties which are harnessed to produce a route to enhance the effectiveness of antibody therapy. 

– In genome editing; The CRISPR system of S. pyogenes is used to recognize and destroy DNA from invading viruses, thereby stopping the infection.

Sources:

Baruah K, Bowden TA, Krishna BA, Dwek RA, Crispin M, Scanlan CN (2012). “Selective Deactivation of Serum IgG: A General Strategy for the Enhancement of Monoclonal Antibody Receptor Interactions”. Journal of Molecular Biology. 420 (1–2): 1–7. doi:10.1016/j.jmb.2012.04.002. PMC 3437440. PMID 22484364.

Deltcheva E, Chylinski K, Sharma CM, Gonzales K, Chao Y, Pirzada ZA, Eckert MR, Vogel J, Charpentier E (March 2011). “CRISPR RNA maturation by trans-encoded small RNA and host factor RNase III”. Nature. 471 (7340): 602–607. Bibcode:2011Natur.471..602D. doi:10.1038/nature09886. PMC 3070239. PMID 21455174.

Foundations in Microbiology (ninth edition) by Kathleen Park Talaro, Barry Chess

STEM CELLS

                     By: N. Shreya Mohan (MSIWM042)

Stem cells are a group of undifferentiated cells that will differentiate into various types cells and proliferate indefinitely. They originate from cell lineages. They exact opposite to the progenitor cells, which does not proliferate indefinitely. In mammal, typically about 50-150 cells combine to form the inner cell mass (ICM) during the blastocyst stage of the embryonic development. These cells are stem cells too, having the ability to differentiate into various cell of the body. But this process is characterized by differentiating into there germ layers (layers that differentiate and give rise to tissues, organs). The three germ layers are ectoderm, endoderm and mesoderm particularly clear in gastrulation stage. These can systematically be isolated and cultured invitro during the stem cell stage and they are known as embryonic stem cells (ESCs). Parallelly, adult stem cells are found in particular areas such as the bone marrow or gonads. Their purpose, unlike the ESCs is to replenish the lost cells of the body, most common stem cells are the hemopoietic stem cells, which replenish blood and immune cells. Mesenchymal stem cells maintain bone cartilage and fat cells. The term “stem cell” was given by Theodor Boveri and Valentin Hacker during the 19^th century. The properties of the stem cell were given by Ernst McCulloh and James Till. We will ponder over the properties too-

• Self-renewal- The ability of the cell to undergo numerous cycles of division and cell growth is known as cell proliferation. This should be done while the undifferentiated state.
• Potency- The capability and power of the cell to differentiate into specialized cell types. Whether it be totipotent, pluripotent, multipotent or unipotent.

Potency refers to the potentiality to be able to differentiate into respective cell types. We will dive into a brief cognizance of each of the potent type:

1. Totipotent- Also known as omnipotent, these stem cells into embryonic as well as cells which are not embryonic. These cells have the ability to make a complete, functional organism. Cells include the product between the fusion of sperm and egg and the cells made after the first few divisions.
2. Pluripotent- They are the known “ancestors” of totipotent cells. They can differentiate into almost all cells, specifically, the cells derived from the three germ layers.
3. Multipotent- These cells will differentiate those type of cells that are closely related to each other.
4. Oligopotent- These cells will only differentiate into particular cells, such as the myeloid stem cells or the lymphoid cells.
5. Unipotent- These cells do not differentiate into any cell, but they do have the property of self-renewal (unlike the progenitor cells).

Stem cell therapy- a boon or a bane?

A filed with high scope, stem cell therapy is being used to treat diseases. Bone marrow replacement is one of a stem cell research which has proven effective in clinical trials. One good advantage of getting treated under this is that they lower symptoms of the disease to some extent. This leads to reduced intake of drugs required to supress the disease. One con is that the patients may require immunosuppression because the patient undergoes radiation before the transplant to remove the existing cells. This can prove detrimental chronically. For ESCs, ethics come into play as few argue that killing a new lifeform is considered unethical. 

Therefore, we should look into several parameters and be aware for it run without hurdles because stem cells have a lot of scope in the future.

 REFERENCES-

https://en.wikipedia.org/wiki/Stem_cell

https://www.medicalnewstoday.com/articles/323343

DIABETES

BY: Ezhuthachan Mithu Mohanan (MSIWM043)

Diabetes is a metabolic disorder characterized by hyperglycaemia which results in a lack of insulin secretion, insulin action, or both the conditions. Metabolic abnormalities are caused due to a low level of resistance to insulin. The effect of symptoms can be classified based on the type and duration of diabetes. Diabetes has also been associated with many metabolic disorders such as acromegaly and hypercortisolism for example insulin resistance has been observed in patients with acromegaly in the liver. Hypercortisolism (Cushing syndrome) produces visceral obesity, insulin resistance, dyslipidaemia which leads to hyperglycaemia and reduces glucose tolerance. Besides, diabetes been associated with metabolic disorders, clinical convergence between type 1 diabetes (T1D), and type 2 diabetes(T2D) is also observed. T2D patients develop a progressive decline in total beta-cell mass. Thus there are many interlinked complications due to diabetes.

According to the report by WHO 2019, 10 main issues demand attention one of them is noncommunicable diseases such as diabetes, cancer, and heart disease. These are collectively responsible for 70% of deaths worldwide. According to the National Health Portal, the Government of India, nearly 5.8 million deaths occur due to noncommunicable diseases in India (WHO 2015). As per data provided by Directorate General of Health Services Ministry of Health & Family Welfare, Government of India (MoHFW) 2016-2017, 2.24 core persons were screened for Common noncommunicable diseases like diabetes, hypertension, cardiovascular disorders, and common cancers. From this, 9.7 % was diagnosed to be diabetes, 12.09% was diagnosed to be hypertension, 0.55% was diagnosed to be cardiovascular disease and 0.17% was with common cancers.

Events occurred from discovery of Diabetes to development of various drugs 

YEAR	EVENTS
1552 BC	HESY-RA documented urination as symptom of mysterious disease
133 AD	Araetus of Cappodocia coined the word diabetes
1675	Thomas Willis coined the word mellitus
1776	Dobson confirmed presence of excess sugar in patients
1800	Discovered chemical test for presence of sugar in urine
1700’s and 1800’s	Physician began to realize dietary changes help manage diabetes
1857	Claude Bernard confirmed that the diabetes occur due to excess glucose production
1870’s	During Franco Prussian war French physician Apollinaire Bouchardat proved that the diabetes patients symptoms improved due to war related food rationing
1889	Oskar Minkowski and Joseph Von Mering extract obtained from dogs pancreas
Early 1900	Development of oat cure, potato therapy, starvation diet.George Zuelzar injected pancreatic extract to control diabetes
1916	Boston scientist Elliott Joslin wrote book “ The Treatment Of Diabetes Mellitus “
1922	Frederick Banting discovered insulin to treat diabetes and won Nobel Prize in medicine 1923
1978	Production of recombinant human DNA insulin
1996	For the treatment of type 22 diabetes Thiazolidinediones (TZDs) were introduced.
2005	The  amylin analogue known as pramlintide, which was approved by the FDA
2008	Colesevelam approved for type 2 diabetes by FDA
2009	Bromocriptine approved for diabetes
2013	Canagliflozin  is the first SGLT- 2 inhibitor  approved by FDA  [Sodium Glucose Co-Transporter 2 Inhibitors], Dapagliflozin approved in 2014 by FDA

(Source: Saudi Med et al., 2002, John et al., 2014)

Diagnosis of Diabetes: 

There are several methods used for the diagnosis of Diabetes Mellitus. According to American Diabetes Association (ADA) the most standard diagnostic criteria is as follows 

1. Hemoglobin A1c (HbA1c)
2. Fasting Plasma Glucose (FPG)
3. Oral Glucose Tolerance Test (OGTT)

 Hemoglobin A1c (HbA1c):

The average level of blood sugar over past two to three months can be diagnosed using hemoglobin A1c test. The main advantage of this type of diagnosis is that there is no need of fasting. A1c is measured using percentage The standard referred by ADA for normal person is less than 5.7%.

 Diagnosis of Diabetes by checking Hemoglobin A1c (HbA1c)

	Hemoglobin A1c
Normal	Less than 5.7%
Prediabetes	5.7% to 6.4%
Diabetes	6.5% higher

Fasting Plasma Glucose (FPG):

It is used to check fasting blood sugar levels. The patient should fast for 8 hours before the test. It is mainly done during morning. For normal person the FPG is lower than 100mg/dl.

Diagnosis of Diabetes by checking Fasting Plasma Glucose (FPG)

	FPG
Normal	100mg/dl or less
Pre diabetes	100 mg/dl to 125 mg/dl
Diabetes	126 mg/dl or high

Oral Glucose Tolerance Test (OGTT)

This method is used to diagnose blood sugar level before and after 2 hours of a sweet drink. For normal person the OGTT is less than 140mg/dl

 Diagnosis of Diabetes by checking Oral Glucose Tolerance (OGTT)

	OGTT
Normal	140mg/dl or less
Pre diabetes	149 to 199mg/dl
Diabetes	200 mg/dl or high

Pathogen profile of Klebsiella pneumoniae:

BY: SHAILY SHARMA (MSIWM041)

Klebsiella pneumoniae is the pathogen that causes pneumonia and septicemia (blood infections) which is usually found in the normal flora of the mouth skin and the intestines. It may also cause meningitis and bacteremia.

Normally when they occur in the intestines, the organism is harmless. However, the spreading of the organism to other parts pf the body and under certain conditions causes diseases in humans.

Clinically, it is one of the most significant members of the genus Klebsiella of the Enterobacteriaceae. In the recent years, one of the most important pathogens of the nosocomial infections, involving the urinary and the pulmonary systems, has been the Klebsiella species. 

Naturally, it occurs in the soil and about 30 percent of the strains of Klebsiella show nitrogen fixing abilities under anaerobic conditions.

• Microscopic morphology: 

• It is a gram-negative organism that occurs in the encapsulated form.
• It is a straight rod-shaped organism around 1 to 2 micrometers in length.
• It is a non-motile organism which is facultatively anaerobic.
• On MacConkey agar medium it appears as a mucoid lactose fermenter.

• Habitat:

• It is usually found in the mouth, skin and intestines of humans as normal flora.

• Virulence factors:

• The bacterium possesses a thick polysaccharide capsule which prevents the ingestion of the organism by the hosts phagocytes and somatic antigen from being detected by the host’s antibodies.
• The bacterium also shows the presence of a thick lipopolysaccharide capsule which makes the serum complement activation more difficult for the host’s immune system.
• K. pneumoniae protects itself and avoids damage by the host’s complement proteins by the extreme length of the molecules comprising the capsule and allows the membrane attack complex (MAC) to form away from the membrane. This helps in the prevention of opsonization and insertion of the MAC.
• The bacterium uses the host’s ferric-siderophore receptors to activate its own Enterobactin-mediated iron-sequestering system.

• Primary infections/disease:

• Most commonly, Klebsiella causes pneumonia. Typically, in the form of bronchopneumonia and bronchitis. 
• The organism is transmitted when a person is directly exposed to the bacteria. The bacteria must enter either directly enter the respiratory tract to cause pneumoniae or the blood stream to cause a bloodstream infection.
• These patients have a higher tendency to develop other complications like lung abscess, cavitation, empyema and pleural adhesions.
• Apart from or in addition to pneumonia, Klebsiella causes other infections like infections of the lower biliary tract, urinary tract and also infection of and around surgical wound sites. 
• The range of these clinical infections include diseases like cholecystitis, diarrhea, upper respiratory tract infection, meningitis, sepsis etc. 
• The bacterium can also enter the blood post sepsis and septic shock.
• In most cases, patients suffering from Klebsiella pneumoniae cough up a characteristic sputum in addition to fever, nausea, tachycardia, and vomiting.
• If a person acquires the infection in a community setting, like in a mall, community-acquired pneumonia occurs.
• A urinary tract infection (UTI) may also be caused by the pathogen if it enters one’s urinary tract. It typically occurs in older women.
• The pathogen may also cause wound infections like cellulitis, necrotizing fasciitis and myositis if it enters through a break in the skin and affects the soft tissue.

• Diagnosis:

• Susceptibility testing for (ESBL) Extended spectrum β-Lactamase.

• Other tests that can be done for the diagnosis of K. pneumoniae include:

1. CBC or complete blood count.
2. Sputum culturing of the patient.
3. Radiography of the chest to check for lung abnormalities visually.
4. CT scans.

• Treatment:

• The treatment for Klebsiella pneumoniae infections mainly depends upon the patient’s health conditions, medical history and the level of severity of the disease. 
• Treatment is by antibiotics like aminoglycosides and cephalosporins.

Sources: 

 Ryan, KJ; Ray, CG, eds. (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. ISBN 978-0-8385-8529-0.

 “Klebsiella species – GOV.UK”. www.gov.uk

Overview of infections of respiratory tract and its pathogens

By: Shaily Sharma (MSIWM041)

• A brief overview of the infections of the respiratory tract and its pathogens:

The respiratory tract along with the gastrointestinal tracts is one of the major connections between the interiors of the body and the outside environment.

The respiratory tract is the pathway is that pathway of the body through which fresh oxygen enters the body and removes the excess carbon dioxide which is not needed by the body. 

• Anatomy of the respiratory system:

• Broadly, the respiratory system of humans can broadly be divided into two distinct areas; the upper and the lower respiratory tracts.
• The parts that consist the lower respiratory tract are:

1. Trachea
2. Bronchi, and
3. Bronchioles

• The respiratory pathway begins with the nasal and the oral passages. These passages serve to humidify the air that is inspired. These pathways extend past the nasopharynx and the oropharynx to the trachea and then to the lungs.
• The trachea is the organ that divides into the bronchi, which then further subdivides into the bronchioles. The bronchioles are the smallest branches of the trachea which finally terminate into the alveoli.
• Approximately 300 million alveoli are said to present in the lungs. These mainly serve as the primary, microscopic, gas exchange structures of the respiratory tract.

• The lungs (along with the respiratory system) and the heart lie in the thoracic cavity. 
• The thoracic cavity has three partitions that are separated from one other by the pleura (the pleura majorly cushions the lungs and reduce the friction which may develop between the lungs, rib cage and the chest cavity. It is a two layered membrane covering the lungs.)
• The lungs occupy the right and the left pleural cavity while the mediastinum (the space between the right and the left lungs) is occupied by the esophagus, trachea, large blood vessels along with the heart.

• Pathogenesis of the respiratory tract:

• The success of an organism to cause disease is mainly dependent on the organism’s ability to cause disease (pathogenesis), and
• The human hosts ability to prevent the infection (strength of the host’s immune system)
• The host factors that help in non-specifically protect the respiratory tract from infection are:

1. Nasal hair
2. Convoluted passages and the mucous lining of the nasal turbinate
3. Secretory IgA and non-specific antibacterial substances (like lysozyme) in respiratory secretions
4. The cilia and the mucous lining of the trachea and reflexes such as coughing and sneezing. 

• In addition to the non-specific hosts defenses, normal flora of the nasopharynx and the oropharynx help in the prevention of colonization of the upper respiratory tract. 

Microorganism factors:

Organisms possess certain traits that promote colonization leading to infection in the host. The factors that influence the respiratory tract infections are –

1. Adherence: 

• The potential of a microorganism depends, in one way or the other, on its ability to establish a stable contact/foothold on the surface of the host by the process of adherence. 
• The ability of microorganisms to adhere to the host surface is dependent on two factors:

1. Presence of normal flora, and
2. Overall state of the host.

•  Surviving or growing on host tissue without causing harmful effects is called colonization. 
• Most etiologic agents must first adhere to the mucosa of the respiratory tract to some extent before they can cause harm.
• Example: Streptococcus pyogenes possess specific adherence factors and its gram-positive cell wall contains lipoteichoic acids and M proteins. Many gram-negative bacteria like Enterobacteriaceae, Pseudomonas spp., Bordetella pertussis, adhere by the means of proteinaceous fingerlike projections called fimbriae. 
• Viruses possess either a hemagglutinin or other proteins that mediate that epithelial attachment.

2. Toxins: 

• Certain microorganisms are considered to be etiologic agents of disease because they possess virulence factors that are expressed in every host. 
• Example: Corynebacterium diphtheriae. 
• Some strains of Pseudomonas aeruginosa also produce toxins which are similar to the toxins of Diphtheria.
•  Bordetella pertussis which is the causative agent of whooping cough produces toxins that play a role in inhibiting the activity of phagocytic cells and damaging the cells of the respiratory tract.

3. Microorganism growth: 

• Pathogens cause disease by merely growing in the host tissue, interfering with normal tissue function and attracting host immune effectors, such as neutrophils and macrophages.
• Example: S. pyogenes, M. tuberculosis, Mycoplasma pneumoniae, etc.

4. Avoiding the Host Response: 

• Certain respiratory tract pathogens possess the ability to evade host defense mechanisms.
•  S. pneumoniae, H. influenza, K. pneumoniae and others possess polysaccharide capsules that serve both to prevent engulfment by phagocytic host cells and to protect somatic antigens from being exposed to host immunoglobulins.

• Organisms of the respiratory tract and agents that cause diseases: 

Pathogens may or may not cause the respiratory infection but can be present as a part of normal flora.

•  Some of the pathogens that exist and results in the respiratory infection are referred to as true pathogens. 
•  Some of the pathogens that are present in the body but never cause an infection until and unless they are met with the favorable conditions are called

as opportunistic pathogens.  

• Possible pathogen: they are the pathogens that are likely to cause respiratory

infections.

• Example: Actinomyces spp., Haemophilus influenzae, Enterobacteriaceae, etc.
•  Rare pathogen: pathogens that may cause a respiratory infection are rare

pathogens. Example: Coxiella burnetti, Brucella spp., Salmonella spp, etc.  

•  Definite respiratory pathogen: pathogens that always cause respiratory infections are called as definite respiratory pathogens.
• Example: Bordetella pertussis, Blastomyces dermatitidis, Legionella spp., etc.
• Different types of agents that cause respiratory diseases are bacteria, fungi or

viruses.  

•  Bacterial agents: the bacterial agents that cause respiratory infections are

Mycoplasma spp., Streptococcus pneumoniae and Neisseria meningitides. 

• Fungal agents: the fungal agents that cause respiratory infections are Candida

albicans, Cryptococcus neoformans and Histoplasma capsulatum.  

•  Viral agents: the viral agents that cause respiratory infections are human

metapneumovirus, adenovirus, enteroviruses, and herpes simplex virus. 

• Major respiratory diseases are caused by M. tuberculosis, S. pyogenes and

K.pneumonia.

Sources:

• Foundations in Microbiology, Author: Kathleen Park Talaro, Barry Chess
• https://basicmedicalkey.com/infections-of-the-lower-respiratorysystem/#:~:

text=The%20presence%20of%20normal%20flora,harmful%20effects%20is%20termed%20colonization.

DETECTION OF PEPTIDE HORMONES

BY: Reddy Sailaja M (MSIWM030)

HORMONES

A hormone is a signaling molecule secreted by endocrine glands in response to physiological stimuli in multi cellular organisms. These hormones circulate in blood and reach its destination to exert specific function. Hormones help maintain physiological and behavioral functions in the organisms.

Hormones are classified into three main classes:

• Steriod hormones – Lipid soluble and move across plasma membrane of the targeted cells.
• Peptide hormones – Water soluble and act through cell surface receptors present on the targeted cells.
• Aminoacid derivatives

Table 1: Three classes of hormones

Peptide hormones

Peptide hormones are made up of small amino acid chains called, peptides. Peptide hormones are synthesized in the cells from amino  acids based on mRNA sequence that is derived from DNA template within the nucleus.

Peptide hormones can’t navigate across plasma membrane of the cell. Hence, they exert their function by binding to the receptor present on the cell surface of the target cell that in turn trigger signal transduction and cellular response. Some peptide hormones like parathyroid hormone-related protein, angiotensin II etc interact with intracellular components within cytoplasm or nucleus by an intracrine mode of interaction.

Some of the examples of peptide hormones are as follows:

• Adrenocorticotrophic hormone
• Thyroid stimulating hormone
• Vasopressin
• Angiotensin II
• Antrial natriuretic peptide
• Calcitonin
• Follicle stimulating hormone
• Insulin
• Growth hormone
• Parathyroid hormone
• Prolactin

Table 2: Main peptide hormones – details and functions

Detection of peptide hormones

As peptide hormones circulate in blood to reach their destination, serum generally acts as the source of detection and measurement.

The following are the main detection methods used to detection peptide hormones:

1. Sandwich ELISA technique:
2. In sandwich ELISA method, two antibodies are used to detect hormone of interest. One of the antibodies is attached to the solid support on the micro titer plate, called as capture antibody.
3. Second antibody labeled with a signal molecule (enzyme or radioisotope or chemilumiscent) acts as detector.
4. When the analyte containing mixture is loaded onto the micro titer plate, capture antibodies bind to the analyte via epitope that is present on the analyte surface and catch hold of analytes.
5. When the detector antibodies are added to the plate, they bind to different location on the analyte.
6. In the enzyme based reaction, when substrate is added, it reacts with enzyme that is attached to the detector body and shows response in the form of color change.

Figure 1: Sandwich ELISA to detect analytes in the blood

• Radioimmunoassay (RIA):
• RIA is an in vitro detection technique that detects and measures antigens (like hormones and other foreign substances) in the blood. RIA technique is discovered by Berson and Yalow in 1960 to analyze insulin levels in blood.
• RIA method is based on the radioactivity measurement associated with antigen-antibody interactions in the reaction.
• A known antigen that is radiolabelled is incubated with antibody at known concentrations.
• When the analyte containing solution is added to the labelled antigen-antibody mixture, antigen of interest replaces labelled antigen and bind to the antibody.
• More the antigen of interest present in the solution, more labelled antigen will be displaced and replaced with antigen of interest.

Figure 2: Radioimmunoassay

• Enzyme multiplied Immunoassay Technique (EMIT):
• EMIT is more easy and equivalent detection method, both qualitatively and quantitatively to measure wide-range of analytes from the serum.
• EMIT is based on the principle that the amount of analyte present in the solution is directly proportional to the inhibition of enzyme-substrate reaction complex.
• In this technique, initially a known analyte is labelled with an enzyme and antibody specific to drug is allowed to bind drug-enzyme complex. This results in inhibition of enzyme activity.
• When the solution containing analyte is added to the above mixture, the analyte releases the antibody from the drug-enzyme complex, thereby increasing enzymatic activity.
• Therefore, enzyme activity is proportional to the analyte present in the sample added and is measured by absorbance value changes of the enzyme.

Figure 3: Enzyme multiplied Immunoassay Technique

• Immunoradiometric assay (IRMA)
• IRMA utilizes radiolabeled antibodies to detect analytes of interest.
• In this technique, antibody is directly labeled with radioisotopes rather than using two antibodies as in other immune assays.

• When an analyte containing solution is added to micro titer plateradiolabeled antibodies bind to the specific epitopes of the anlytes and forms the antigen-antibody complex.

• I125 and I131 radioisotopes used in general for this assay.
• Unbound radiolabeled antibodies are removed from the plate by second wash during the process.

Figure 4: Immunoradiometric assay

The other peptide hormone detection methods are listed below:

• Ultrafiltration
• Chromatography
• Time resolved fluorescence
• Mass spectrometry
• Two site immunometric technique

Poxvirus

BY- K. Sai Manogna (MSIWM014)

Introduction :

Poxviruses are part of the family Poxviridae and can infect humans and animals alike. Smallpox (variola), vaccinia, cowpox, monkeypox, buffalopox, aracatuba, and cantagalo viruses are orthopoxviruses. Orf virus, pseudo cowpox virus, deer poxvirus, bovine papular stomatitis virus, and sealpox virus are parapoxviruses. Yatapoxviruses include the tanapox virus, which is commonly found in Africa. The human poxvirus, the molluscum contagiosum virus, contains mollusc poxviruses. 

Smallpox is unique to humans and molluscum contagiosum. In humans, other viruses cause unusual zoonotic infections. The vaccinia virus used for vaccines will infect humans as well. Molluscum contagiosum is also a human-unique poxvirus. Other human poxvirus infections are caused either by zoonotic exposure to animal poxviruses or scheduled or unintended vaccinia administration. This virus is spread through close contact, often via sexual contact. 

Recently, laboratory exposures have been reported that have contributed to infection with vaccinia and tanapox viruses, widely used as vectors for experimental vaccines. Due to transmission to contacts, civilian and military personnel’s smallpox vaccination program resulted in multiple infections. 

Incubation Period: Infections with smallpox are caused by inhalational penetration to nasal, oral, or pharyngeal droplets. The incubation period is from 10-14. Viruses of smallpox multiply locally and spread to the nearby lymph nodes. On days 3-4, asymptomatic viremia ensues, spreading to the bone marrow and spleen. On approximately day 8, secondary viremia begins. Generalized signs of fever and a toxic appearance are associated with this secondary viremia. In the dermis blood vessels, the virus in leukocytes then becomes localized. Then the stereotypical smallpox rash emerges. 

The replication: 

1. Generally, poxviruses replicate only in the cytoplasm and can in cells without a nucleus, unlike most DNA viruses. 

2. Either through endocytosis or by a fusion event, the virion enters the cell. 

3. For later replication cases, the viral core reaches the cytoplasm and functions as a scaffolding. 

4. Besides, many necessary enzymes such as viral transcriptase, transcription factors, capping and methylating enzymes, and a poly(A) polymerase are transported by the virus. 

5. Therefore viral DNA transcription is rapidly initiated and about 100 early viral genes, especially enzyme coding genes that are involved in viral DNA replication, are triggered.

6. At the same time as DNA replication, transcription of intermediate and late genes is initiated. 

7. In specific cytoplasm areas, virus assembly and immature viruses can be visualized very quickly. 

8. The Virions travel to the Golgi complex during maturation, where they are enveloped before being released by budding or cell disruption. 

9. Some virions are enveloped, and they may have certain benefits, including cell uptake speed.

Other poxviruses, primarily localized diseases, typically follow the same pattern of evolution. An exception is the outbreak of monkeypox, which progresses to a variola-like clinical syndrome. Monkeypox infections, as in the North American epidemic, can vary from mild infections with few lesions to severe systemic diseases that mimic smallpox. At the inoculation site, the Molluscum contagiosum virus also replicates, but the skin lesions’ character is distinct. 

Epidemiology: 

Human poxvirus infections are obtained from animal reservoirs, except molluscum, which is primarily a human disease. The reservoir is recognized and distributed globally in some cases, as is the case with ovine and bovine parapoxviruses. An occupational hazard of those who interact with the contaminated reservoir hosts is human contamination with these viruses. 

Monkeypox is confined to West Africa, and squirrels are more critical than monkeys as reservoir hosts. The cowpox virus is limited to Europe and the western part of the former Soviet Union. Bovine cowpox is unusual, and the most frequently recorded host is the domestic cat. Lack of definitive knowledge on the cowpox virus reservoir host, but it is presumably tiny wild rodents. Cases occur without established contact with cats or cattle, and it is possible to spread indirectly through barbed wire or brambles. 

Restricted natural person-to-person transmission of monkeypox, but not more than four or five generations, has been observed. Parapox and cowpox diseases spread from person to person occasionally, if ever. Molluscum’s person-to-person spread is historically associated with physical contact sports (e.g., wrestling) and towel sharing. However, there is growing evidence that molluscum sexual transmission is significant. 

Traditionally, the Vaccinia virus is known as a laboratory virus without a natural reservoir. Although its host reservoir lacks information, the buffalopox virus, now considered a vaccine virus variant, appears to have established itself in India. It is important to note that such strains may become developed in animal populations and interact with genetically related viruses circulating in them due to the possible use of recombinant vaccinia virus vaccines. 

Diagnosis: 

In some instances, a right diagnosis would be made possible by the existence of the lesions and a careful history of interaction with the infected reservoir animal or other infected people; difficulties can occur if no such contact is known. This is perhaps most prominent with human cowpox, as most cases are not linked to a single source, and occasionally an anthrax clinical diagnosis is made. 

An effective means of rapid diagnosis is electron microscopy of the vesicle or scab material; poxviruses and herpesviruses are readily differentiated, and the characteristic morphology of parapoxviruses can be identified. Immunofluorescence of infected cell cultures can distinguish morphologically related poxviruses from various genera for e.g., Orthopoxviruses and Yatapoxviruses. While the molluscum virus has yet to be cultivated in tissue culture and chicken embryos, the other poxviruses are easily isolated. Cultivation then enables biologic and serum neutralization samples to be established. Near antigenic relationships within genera compromise precise recognition through antibody detection, but knowledge of the host and geographic range will validate a presumptive diagnosis. 

Treatment: 

Infections of Variola have been globally eradicated. There is a concern, however, about the reintroduction of smallpox through bioterrorism. An international health care emergency would precipitate the reappearance of smallpox. Local and federal public health authorities should be informed of suspected cases of smallpox. 

For smallpox or vaccinia, no known remedies are currently available. Several nucleoside and nucleotide analogues, including variola, vaccinia, monkeypox, cowpox, molluscum contagiosum, and orf, have shown Invitro activity and in vivo antiviral activity against various poxviruses. So far, Cidofovir and a number of its derivatives are the most efficient.

CORONARY ARTERY DISEASE/ ISCHEMIC HEART DISEASE

BY: Ria Fazulbhoy (MSIWM031)

How does it occur?

This disease is currently the leading cause of death, worldwide. The ischemic heart disease is also known as coronary artery disease (CAD), atherosclerotic heart disease and coronary heart disease (CHD).

The disease occurs due to the blockage of the arteries leading to inadequate blood supply to the heart due to a number of reasons like building of plaque, excess exertion, high levels of cholesterol, etc. While narrowing may be caused by a blood clot or blood vessel constriction as well, it is more often caused by plaque accumulation, called atherosclerosis.

In the blood, cholesterol particles begin to accumulate on the walls of the arteries that supply the heart with blood. Eventually, it can form deposits called plaques. These deposits narrow the arteries and obstruct the flow of blood eventually.

The amount of oxygen supplied to the heart muscle is decreased by this reduction in blood flow. The heart muscle cells die, which is called a heart attack or myocardial infarction, when the blood supply to the heart muscle is completely blocked (MI).

Risk factors that increase chances of the disease:

The risk of developing ischemic heart disease is raised by a variety of variables. Not all individuals with risk factors are going to get ischemic heart disease. There are risk factors for ischemic heart disease include:

• Diabetes
• Family history of the condition of the heart
• High cholesterol in the blood
• Blood Pressure High
• Strong triglycerides in the blood
• Obesity
• Inactive physique
• Smoking and other forms of tobacco

Symptoms:

People can experience ischemic heart disease symptoms either regularly or only occasionally, depending on the severity of the case. Some common symptoms experienced by patients include:

1. Angina pectoris

When the heart muscle is deprived of enough oxygen, the pain endured is called angina pectoris. This is a clinical condition characterized by chest, chin, shoulder, back, or arm pain that is normally exacerbated by exercise or emotional stress and immediately relieved by rest or nitroglycerin use.

2. Breath shortage: One can experience shortness of breath or severe exhaustion with exercise if the heart can’t pump enough blood to meet the needs of your body.

3.  Heart attack. A coronary artery that is totally blocked can cause a heart attack. Crushing pressure in one’s chest and pain in your shoulder or arm, sometimes with shortness of breath and sweating, are the classic signs and symptoms of a heart attack.

4.  Arrhythmia – abnormal heart rhythm: Inadequate blood flow to the heart or heart tissue damage can interfere with the electrical impulses of your heart, causing irregular heart rhythms.

Diagnosis:

1. Electrocardiogram – ECG or EKG: The electrical activity, rate, and regularity of your heartbeat are calculated by
2. Echocardiogram: A image of the heart is generated using ultrasound (special sound wave).
3. Exercise stress test: Tracks your heart rate as you walk on a treadmill. This helps to decide how well the heart functions as more blood needs to be pumped.
4. Chest X-ray:  In order to create an image of the heart, lungs, and other organs in the chest, x-rays are used.
5. Coronary angiogram: Monitors blockage and passage of blood into the coronary arteries. In order to detect dye injected through cardiac catheterization, X-rays are used.
6. Coronary artery calcium scan:  A computed tomography (CT) scan searches for calcium accumulation and plaque in the coronary arteries.

Treatment:

Treatment given to patients suffering from Ischemic heart disease can include drug therapy, regular exercise, quitting of smoking/ tobacco, healthy dietetic.

Medications used to treat the disease include:

• Angiotensin-converting enzyme (ACE) that relax blood vessels and decrease blood pressure.
• Angiotensin receptor blockers (ARBs) which help in lowering the blood pressure.
• Anti-ischemic agents like ranolazine, for example (Ranexa)
• Antiplatelet drugs that stop blood clots from forming
• Beta-blockers that decrease the heart rate
• Calcium channel blockers that lower the heart muscle workload

PARKINSON’S DISEASE

BY: Ria Fazulbhoy (MSIWM031)

Parkinson disease is a disease related to the nervous system and nerve damage. It drastically affects the patient and progressively worsens over time. The progression takes place in 5 stages, which go from low risk symptoms to more drastic ones.  It affects over 100,000 people worldwide each year. At present, approximately more than 10 million people suffer from this disease. However, it is noticed that men have a higher chance of developing the disease, a reason not clear as yet. Other factors like genetics, environmental cues (like exposure to toxins), age, etc can also play a role in the development of PD.

What happens in Parkinson’s disease

1. Parkinsons affects the central nervous system and the brain.
2. It mainly affects a region in  the brain, in the basal ganglia, which is known as substantia nigra.
3. Substantia nigra consists of some cells which produce the chemical hormone and neurotransmitter, dopamine – the feel good hormone.
4. Dopamine is an extremely important catecholamine in the brain which is responsible for various cues, functions, carrying chemical messages and also contributes to the pleasure pathway i.e how we feel positive emotions like joy, satisfaction and pleasure.
5. In Parkinson disease, the levels of dopamine in a individual drop due to the death of cells which produce dopamine and are present in substantia nigra.
6. When these dopamine levels decrease, it causes abnormal activity of the brain, which in turn leads to severe symptoms like impaired movement, depression, sleeping problems, etc.

Symptoms of Parkinson’s disease

The signs and symptoms generally differ from patient to patient. Early signs are almost always undetectable, and the disease is diagnosed most commonly in the later stages. Sometimes, symptoms can be present only on one side of the body (left or right), remain severe on this side and eventually spread to the rest of the body. Parkinson’s disease symptoms include:

• Tremors: Patients often feel tremors in their limbs such as hands, fingers and legs. Can later also occur in jaws and tongue. It becomes progressively worse and can also cause problems in daily life activities such as eating, bathing, wearing clothes etc.

• Impaired balance and posture: Posture becomes topped, and patients find it hard to keep balance. External help and support is required in the later stages.

• Depression and bad dreams: Owing to the decreased levels of dopamine in the brain, and other attributes such as loss of physical control over body, slow movement and psychological effects can lead to depression and other personality disorders. This is accompanied with anxiety, fear and loss of motivation.

• Changes in talking and speech: In some cases, the speech of the patient can become highly affected. It becomes slurry, soft, sometimes quiet, other times slow, and is expressionless and monotonous.

• Bradykinesia (slowed movement) : Simple tasks like walking, sitting, eating become time consuming and movement becomes slowed. Steps might get shorter. External help and assistance is needed.

Treatment and prevention

Unfortunately, as of today, there is no complete solution or cure for the complete recovery from Parkinson’s disease Intense research work is being done in labs across the globe to find a solution for the same. Symptoms and side effects can be used by the intake of prescription drugs (like anti depressants), dopaminergics, muscular antagnostics, etc. Physical exercise can also help keep the body moving and fit. Life expectancy can increase with proper care and attention towards the patient.