VASCULITIS

Vasculitis is inflammation of the vessel wall; although there are frequently systemic manifestations (including fever, malaise, myalgias, and arthralgias), specific symptoms depend on the vascular bed that is involved.Vasculitis can result from infections, but it more commonly has an immunologic basis such as immune complex deposition, ANCAs, or anti-EC antibodies.Different forms of vasculitis tend to specifically affect vessels of a particular caliber and location

Vasculitis, or inflammation of vessel walls, occurs in diverse clinical settings. Depending on the vascular bed affected (e.g., central nervous system vs. heart vs. small bowel), the manifestations can be protean. Besides the findings referable to the specific tissue(s) involved, clinical manifestations common to these entities typically include constitutional signs and symptoms such as fever, myalgia, arthralgias, and malaise.

Vessels of any type in virtually any organ can be affected, and most vasculitides can affect all small vessels from arterioles to capillary to venules. Nevertheless, several of the vasculitides tend to affect only vessels of particular caliber or tissue beds; thus, there are vasculitic entities that primarily affect the aorta and medium-sized arteries, while others principally affect only smaller arterioles. Some 20 primary forms of vasculitis are recognized, and classifications schemes attempt (with variable success) to group them according to vessel size, role of immune complexes, presence of specific autoantibodies, granuloma formation, organ tropism, and even population demographics

SHOCK

Shock causes systemic hypoperfusion due to either reduced cardiac output or reduced circulating blood volume.The most common causes of shock are cardiogenic (cardiac pump failure due, for example, to myocardial infarction), hypovolemic (due, for example, to blood loss), and sepsis (due to infections).Septic shock results from the host innate immune response to bacterial or fungal cell molecules (most commonly endotoxin), with systemic production of cytokines, such as TNF and IL-1, that affect endothelial and inflammatory cell activation.Hypotension, DIC, and metabolic disturbances constitute the clinical triad of septic shock.Shock of any form causes pathology by inducing prolonged tissue hypoxic injury.


Shock is the final common pathway for a number of potentially lethal clinical events, including severe hemorrhage, extensive trauma or burns, large myocardial infarction, massive pulmonary embolism, and microbial sepsis. Regardless of the underlying pathology, shock gives rise to systemic hypoperfusion; it can be caused either by reduced cardiac output or by reduced effective circulating blood volume. The end results are hypotension, impaired tissue perfusion, and cellular hypoxia. Although the hypoxic and metabolic effects of hypoperfusion initially cause only reversible cellular injury, persistence of shock eventually causes irreversible tissue injury and can culminate in the death of the patient.

INFARCTION

Infarcts are areas of ischemic, usually coagulative, necrosis caused by occlusion of arterial supply or less commonly venous drainage.Infarcts are most commonly caused by formation of occlusive arterial thrombi, or embolization of arterial or venous thrombi.Infarcts caused by venous occlusion, or in loose tissues with dual blood supply, are typically hemorrhagic (red) whereas those caused by arterial occlusion in compact tissues are pale (white) in color

An infarct is an area of ischemic necrosis caused by occlusion of either the arterial supply or the venous drainage in a particular tissue. Tissue infarction is a common and extremely important cause of clinical illness. More than half of all deaths in the United States are caused by cardiovascular disease, and most of these are attributable to myocardial or cerebral infarction. Pulmonary infarction is a common complication in several clinical settings, bowel infarction is frequently fatal, and ischemic necrosis of the extremities (gangrene) is a serious problem in the diabetic population.

EDEMA

EDEMA

Approximately 60% of lean body weight is water, two-thirds of which is intracellular and the remainder is in extracellular compartments, mostly as interstitial fluid; only 5% of total body water is in blood plasma. The term edema signifies increased fluid in the interstitial tissue spaces; fluid collections in different body cavities are variously designated hydrothorax, hydropericardium, or hydroperitoneum (the last is more commonly called ascites). Anasarca is a severe and generalized edema with profound subcutaneous tissue swelling.

Edema is extravasation of fluid from vessels into interstitial spaces; the fluid may be protein poor (transudate) or may be protein rich (exudate).Edema results from any of the following conditions:

Increased hydrostatic pressure, caused by a reduction in venous return (as in heart failure)Decreased colloid osmotic pressure, caused by reduced concentration of plasma albumin (due to decreased synthesis, as in liver disease, or increased loss, as in kidney disease)Lymphatic obstruction that impairs interstitial fluid clearance (as in scarring, tumors, or certain infections)Primary renal sodium retention (in renal failure)Increased vascular permeability (in inflammation)

Brain Disease

Alzheimer's Disease

This progressive disease damages nerve cells in parts of the brain involved in memory, learning, language, and reasoning. In early stages, short-term memory begins to fail. Over time, functions such as long-term memory

Brain Tumor

Most brain tumors in children are primary tumors, meaning they arise in the brain. In adults, most are metastatic or secondary tumors, meaning the cancer has spread to the brain from the breast, lung, or other part of the body. Nearly 1 in 4 people with cancer will get a secondary brain tumor

Stroke

Medicine has made great strides in diagnosing and treating stroke, in which a blood vessel carrying oxygen and other nutrients to the brain becomes blocked or suddenly bursts

Bronchitis

Bronchitis is an inflammation of the lining of your bronchial tubes, which carry air to and from your lungs. Bronchitis may be either acute or chronic.

Acute bronchitis usually improves within a few days without lasting effects, although you may continue to cough for weeks. However, if you have repeated bouts of bronchitis, you may have chronic bronchitis, which requires medical attention. Chronic bronchitis is one of the conditions included in chronic obstructive pulmonary disease (COPD).

symptoms may include:

• Cough
• Production of mucus (sputum), which can be clear, white, yellowish-gray or green in color
• Fatigue
• Slight fever and chills
• Cause:
• Acute bronchitis is usually caused by viruses, typically the same viruses that cause colds and influenza. Antibiotics don't kill viruses, so this type of medication isn't useful in most cases of bronchitis.
  The most common cause of chronic bronchitis is smoking cigarettes. Air pollution and dust or toxic gases in the environment or workplace also can contribute to the condition

Gastroenteritis

Gastroenteritis is an infection of the gut. It causes diarrhoea, and may also cause vomiting, abdominal pain and other symptoms. In most cases the infection clears over several days, but sometimes takes longer.

A virus is the most common cause of gastroenteritis. For example, infection with noroviruses and adenoviruses are common causes of gastroenteritis in adults in the UK, but other viruses can also be the cause.

Food poisoning (eating food infected with microbes) causes some cases of gastroenteritis.

• 
  
• The main symptom is diarrhoea, often with vomiting as well. Diarrhoea means loose or watery stools (faeces), usually at least three times in 24 hours. Blood or mucus can appear in the stools with some infections.
• Crampy pains in your abdomen (tummy) are common. Pains may ease for a while each time you pass some diarrhoea.

ALLERGY

Allergies occur when your immune system reacts to a foreign substance such as pollen, bee venom or pet dander.


Allergy symptoms depend on your particular allergy, and can involve the airways, sinuses and nasal passages, skin, and digestive system. Allergic reactions can range from mild to severe. In some severe cases, allergies can trigger a life-threatening reaction in your body known as anaphylaxis.

Common allergy triggers include:

• Airborne allergens, such as pollen, animal dander, dust mites and mold
• Certain foods, particularly peanuts, tree nuts, wheat, soy, fish, shellfish, eggs and milk
• Insect stings, such as bee stings or wasp stings
• Medications, particularly penicillin or penicillin-based antibiotics
• Latex or other substances you touch

Blood plasma

Blood is the main bodily fluid and responsible for transporting important nutrients, oxygen, carbon dioxide and waste products to and away from the cells, whereas plasma is the yellow liquid component of blood and constitutes 55% of the total blood volume.
Blood is the main bodily fluid and responsible for transporting important nutrients, oxygen, carbon dioxide and waste products to and away from the cells.

Plasma is the yellow liquid component of blood and constitutes 55% of the total blood volume.

Composition of blood vs plasma

Blood is composed of plasma and different kinds of cells- red blood cells (erythrocytes), white blood cells (leukocytes), and thromobocytes (platelets). The density of blood (1060 kg/m³) is very close to that of pure water (1000 kg/m³).

Plasma contains water (90%), proteins (albumin, fibrinogen and globulins), nutrients (glucose, fatty acids, amino acids), waste products (urea, uric acid, lactic acid, creatinine), clotting factors, minerals, immunoglobulins, hormones and carbon dioxide, i.e. all the components of blood except the red, white blood cells and thrombocytes. Components can either be dissolved (if soluble) or remain bound to proteins (if insoluble). Plasma has the density of 1025 kg/m³.

Diseases

Blood disorders include anemia (insufficient red cell mass), genetic disorders (thalassemia and sickle cell anemia), leukemia (type of blood cancer), haemophilia (inherited clotting disorder), infectious disorders (HIV, Hepatitis B and C, bacteremia, malaria, 

Diarrhea

Diarrhea describes loose, watery stools that occur more frequently than usual. Diarrhea is something everyone experiences. Diarrhea often means more-frequent trips to the toilet and a greater volume of stool.

Signs and symptoms associated with diarrhea may include:

• Frequent, loose, watery stools
• Abdominal cramps
• Abdominal pain
• Fever
• Blood in the stool
• Bloating
• 
  
• A number of diseases and conditions can cause diarrhea. Common causes of diarrhea include:
• • Viruses. Viruses that can cause diarrhea include Norwalk virus, cytomegalovirus and viral hepatitis. Rotavirus is a common cause of acute childhood diarrhea.
  • Bacteria and parasites. Contaminated food or water can transmit bacteria and parasites to your body. Parasites such as Giardia lamblia and cryptosporidium can cause diarrhea.
    Common bacterial causes of diarrhea include campylobacter, salmonella, shigella and Escherichia coli. Diarrhea caused by bacteria and parasites can be common when traveling in developing countries and is often called traveler's diarrhea.
  • Medications. Many medications can cause diarrhea. The most common are antibiotics. Antibiotics destroy both good and bad bacteria, which can disturb the natural balance of bacteria in your intestines. This disturbance sometimes leads to an infection with bacteria called Clostridium difficile, which also can cause diarrhea

Liver Diseases

The liver is

 the largest internal organ in the body. Its main functions are to:

• metabolize most of the nutrients that are absorbed by the intestine

• store nutrients

• produce proteins

• detoxify blood by removing medications, alcohol, and potentially harmful chemicals from the bloodstream and treating them chemically so they can be excreted by digestive or urinary systems

• Different types of liver disorders include hepatitis, cirrhosis, liver tumours, and liver abscess (collection of pus), just to name a few. The focus here will be the two most common forms: hepatitis and cirrhosis.

• Causes of Liver Disorders
  Hepatitis is an inflammation of the liver that can be caused by a virus, by inherited disorders, and sometimes by certain medications or toxins such as alcohol and drugs. Scientists have identified four main types of viral hepatitis: hepatitis A, hepatitis B, hepatitis C, and hepatitis D. A fifth type, hepatitis E, is generally not found in North America.

  • Symptoms of liver diseases include weakness and fatigue, weight loss, nausea, vomiting, and yellow discoloration of the skin (jaundice).

  • The treatment of a particular liver disease depends on its specific cause.

CHoleria

Cholera:


•Cholera occurs only in man

•Cholera causes an acute 

gastroenteritis

•Incubation period is 24 

hours to 5 days

•The disease is 

transmitted by 

contaminated water, milk, fruit, 

vegetable, etc.

•Immunity after infection is short living

•Gastric acidity seems an important 

defense against cholera

•Infection dose 1 ml bacterial cells

GENETICS

GENETICS

•Genetics is the study of heredity and variation, seeking to understand the causes of the resemblances and differences between parents and their progeny

•Genetics of microorganisms

•The «central dogma» of molecular biology is that DNA carries genetic information, which is transcribed on to RNA and then translated as the particular polypeptide

•(DNA - RNA - polypeptide)

•An exception exists in the case of some viruses genetic material is RNA instead of DNA

•Genetics of microorganisms

•The DNA molecule is composed of 

two chains of nucleotides bound 

together in the form of a «double 

helix»

•Each chain has a backbone of 

desoxyribose and phosphate residues 

arranged alternately

•Attached to each desoxyribose is one 

of four nitrogenous bases, the purines: 

adenine (A) and guanine (G), and the 

pyrimidines: thymine (T) and 

cytosine (C)

•Adenine is always linked to thymine, 

and guanine to cytosine: A=T, G=C

•Genetics of microorganisms

•Genetic information is stored in the DNA as a code, the unit of the code (codon) consisting of a sequence of three bases (the code is triplet)

• Each codon specifies for a single aminoacid, but the code is «degenerate» so that more than one codon may exist for the same aminoacid

•A segment of DNA carrying codons specifying for a particular polypeptide is called a «cistron» or gene

•The bacterial chromosome carries about 1000-4000 cistrons.

•Genetics of microorganisms

Structure of operon

•   Lac         Lac P          Lac O            Lac Z - Y -A

•Regulator  Promotor   Operator        Structural genes

•For transcription of RNA for the enzyme synthesis, the RNA polymerase has to attach to the promotor region and travel along the structural genes in sequence.

•The transfer of genetic information from DNA to RNA is called transcription and from RNA to protein is called translation.

•Genetics of microorganisms

•RNA is structurally similar to DNA 

except for three major differences:

•It contains the sugar ribose 

(desoxyribose in DNA)

•One of pyrimidine base is uracile 

instead thymine in DNA

•There are 3 distinct types of RNA on the 

basis of structure and function:

•1.  Messenger RNA (m RNA)

•2.  Ribosomal RNA (r RNA)

•3.  Transfer RNA (t RNA)

•DNA acts as the template for the 

synthesis of mRNA.

•Genotypic and phenotypic 

variations

•The sum total of genes the make up the genetic apparatus of a cell establishes its genotype.

•The phenotype («phaeno»: display) is the physical expression of the genotype in a given environment.

•Genotypic and phenotypic 

variations

•Phenotypic variations

are influenced by the environment, 

limited in range by the genotype, 

temporary and not heritable.

•Variations are genotypic

when they are due to alterations in the 

genome. Genotypic variations are 

stable, heritable and not influenced 

by the environment.

•

They may occur by mutation, or by 

one of the mechanisms of genetic 

transfer or exchange, such as 

transformation, transduction, 

lysogenic conversion and 

conjugation.

•Mutation

•Mutation

is a heritable variation caused by an 

alteration in the nucleotide 

sequence at some point of the DNA

•The sequence of nucleotides in 

DNA can change in either of 2 

ways:

•(a) by substitution of one base pair 

for another as the result of a 

replication error – 

transition or transvertion.

•by breakage of the sugar phosphate 

back bone with subsequent 

deletion or insertion of a DNA 

segment.

•MUTATIONS IN BACTERIA

–Spontaneous (replication error )

–

Induced (mutations are induced by a 

variety of physical, chemical and 

biological agents)

Physical agents

are radiations, heats etc.

Chemical agents

are nitroso compounds, alkylating 

agents, base analogs, and others.

•TRANSFORMATION

•Definition: It is the transfer of genetic information through the agency of free DNA. Pieces of DNA involved in transformation may carry 10 to 50 genes. Factors affecting transformation

–DNA size and state

–Competence of the recipient (Bacillus, Haemophilus, Neisseria, Streptococcus)

•TRANSFORMATION

–Recombination

•TRANSDUCTION

•Definition: Gene transfer from a donor to a recipient by way of a bacteriophage

•

•Bacteriophage (phage): A virus that infects bacteria

•Phage Composition and Structure

•Composition

–Nucleic acid

•Genome size

•Modified bases

–Protein

•Protection

•Infection

•Infection of Host Cells by Phages

•Irreversible attachment

–Base plate

•TRANSDUCTION

•Types of transduction

–Generalized - Transduction in which potentially any dornor bacterial gene can be transferred.

•Generalized Transduction

•Release of phage

.

•Mechanism of F+ x F- Crosses

•DNA transfer

–Origin of transfer

–Rolling circle replication

•

•Transposable Genetic Elements

•Definition:

Segments of DNA that are able to 

move from one location to another

•Properties

–“Random” movement

–Not capable of self replication (not a 

replicon)

–Transposition mediated by site-

specific recombination

•Transposase

–Transposition may be accompanied 

by duplication

•Types of Transposable Genetic Elements

•Insertion sequences (IS)

–Definition: Elements that carry no other genes except those involved in transposition

–Nomenclature - IS1

–Structure

•Types of Transposable Genetic Elements

•Transposons (Tn)

–Definition: Elements that carry other genes except those involved in transposition

–Nomenclature - Tn10

–Structure

•Composite Tns

•

•PLASMIDS

•Definition: Extrachromosomal 

genetic elements that are capable of 

autonomous replication (replicon)

•Episome - a plasmid that can 

integrate into the chromosome

•Classification of Plasmids

•Transfer properties

–Conjugative are transferred from 

bacterium to bacterium (usually 

members of the same species or of very 

closely related species) through 

conjugation

–

Nonconjugative

•Phenotypic effects

–Fertility (F-plasmids)

–Bacteriocinogenic plasmid (Col-

plasmid)

–Resistance plasmid (R factors) (R-

plasmid)

–Enterotoxin plasmid (Ent-plasmid)

–Haemolysin plasmid (Hly-plasmid)

•Structure of R Factors

•RTF

–Conjugative plasmid

–Transfer genes

•Genetic Engineering

•It is now possible to isolate the genes coding for any desired protein from microorganisms and introduce them into suitable microorganisms, in which the genes would be functional directing the production of the specific protein. This is known as the Recombinant-DNA technology or Genetic engineering.

      

Plasmid DNA vaccination

•Multivalent DNA vaccine

   for malaria.

•Against tuberculosis

•Against hepatitis B virus.