VCAM1 gene is the gene responsible for encoding Vascular Cell Adhesion Molecule 1 which as the name suggests functions as a cell adhesion molecule VACM is a cell surface sialoglycoprotein, a type I membrane protein that is a member of the Ig superfamily.

The VCAM-1 gene is expressed on both large and small blood vessels only after the endothelial cells are stimulated by cytokines.  It contains six or seven immunoglobulin domains, It is alternatively spliced  to encode different isoforms in humans.

The VCAM-1 protein is responsible for mediation of the adhesion of lymphocytes, monocytes, eosinophils, and basophils to vascular endothelium.

It also functions in leukocyte-endothelial cell signal transduction and is thought to play a role in  atherosclerosis and rheumatoid arthritis development.

VCAM-1 is a potential target for developing drugs.

Apoptosis programmed cell death that is carried out in multicellular organism. Apoptosis leads to production of cell fragments called apoptotic bodies that phagocytic cells engulf and quickly remove.

Apoptosis is designed to carry out functions of the body development.For example, the differentiation of fingers and toes in a developing human embryo occurs because cells between the fingers apoptose, separating the digits.

Between 50 and 70 billion cells die each day due to apoptosis in the average human adult.

A defective apoptotic processes have been implicated in an extensive variety of diseases which iclude atrophies in case of increased apoptosis and cancer when apoptosis is insufficient.

Steps Of Apoptosis

Chemotaxis is the phenomenon in which somatic cells, bacteria, and other single-cell or multicellular organisms direct their movements according to certain chemicals in their environment.

In bacteria, chemotaxis is important for finding food by moving towards the highest concentration of food molecules, or to move away from dangers.

In multicellular organisms, chemotaxis is critical for development and function.

Positive chemotaxis occurs if the movement is toward a higher concentration of the chemical in question.

Negative chemotaxis occurs if the movement is in the opposite direction.

Ligand is a substance that forms a complex with a biomolecule to serve a biological purpose.

It acts as a signal triggering molecule, binding to a site on a target protein.

the forces included in the binding process may be ionic bonds, hydrogen bonds or van der Waals forces. High affinity ligand binding results from greater intermolecular force between the ligand and its receptor while low affinity ligand binding involves less intermolecular force between the ligand and its receptor.

The binding is usually reversible.

Ligands may be substrates, inhibitors, activators, and neurotransmitters.

A ligand that binds to a receptor triggers a physiological response. The site where the ligand is bound is known as the binding or active site of the protein.

The binding of a ligand by a protein is generally quite specific.

Addressin  Endothelial Cell Receptor is a receptor for adddresssin.

Addressin is also known as mucosal vascular addressin cell adhesion molecule 1.

It is an extracellular protein of the endothelium of venules.

Addressins are the ligands to the homing receptors of lymphocytes.

Oseteopontin is a extracellular linking protein which is also known by the names of  bone sialoprotein I , early T-lymphocyte activation 1, secreted phosphoprotein 1, 2ar and Rickettsia resistance.

It  is a  glycoprotein that was first identified in 1986 in osteoblasts.

Apart from, the protein is also expressed in other tissues bone.

Osteopontin gene is located on the long arm of chromosome 4 region 13 (4q13). The protein is composed of ~300 amino acids residues and has ~30 carbohydrate residues attached including 10 sialic acid residues. The protein is rich in acidic residues: 30-36% are either aspartic or glutamic acid.

Osteopontin is synthesized in fibroblasts, preosteoblasts, osteoblasts, osteocytes, odontoblasts, some bone marrow cells, hypertrophic chondrocytes, dendritic cells, macrophages, smooth muscle, skeletal muscle, endothelial cells, and extraosseous cells in the inner ear, brain, kidney, and placenta.

Synthesis of osteopontin is stimulated by calcitriol. Regulation of the osteopontin gene is incompletely understood.

Osteopontin has been implicated as an important factor in bone remodeling, immune functions, chemotaxis and T cell activation and apoptosis.

Osteopontin gene might find clinical application in wound healing, bone turnover, tumorigenesis, inflammation, ischemia and immune responses, allergy and asthma ad immune disorders

Peyer’s patches aggregations of lymphoid tissue usually found in the lowest portion of the small intestine, the ileum.

Peyer’s patches are observable as elongated thickenings of the intestinal epithelium.

They have been named after the seventeenth century Swiss anatomist, Hans Conrad Peyer.

Microscopically, Peyer’s patches appear as oval or round lymphoid follicles (similar to lymph nodes) located in the lamina propria layer of the mucosa and they extend into submucous of the ileum.

Peyer’s patches are more numerous in younger individuals and become less prominent with age. Approximately 30 to 40 patches or bundles occur in an individual’s intestine.

Function

The Peyer’s patches contain high concentrations of white blood cells that help protect the body from infection and disease.  Digestive tracts, are constantly exposed to a wide variety of harmful microorganisms. Peyer’s patches, detect antigens such as bacteria and toxins and mobilize  antibodies.

Pathogenic microorganisms and other antigens entering the intestinal tract encounter macrophages, dendritic cells, B-lymphocytes, and T-lymphocytes found in Peyer’s patches and other Mucosa Associated Lymphatic Tissue (MALT).

Though protective, the hypertrophy of Peyer’s patches can cause intenstinal problems.

A stimulus (pl. stimuli) is a detectable change in the internal or external environment. The ability of an organism or organ to respond to external stimuli is called sensitivity.

When a stimulus is applied to a sensory receptor, it elicits or influences a reflex via stimulus transduction. A stimulus is often the first component of a homeostatic control system.

A pathogen is an infectious agent such as a virus, bacteria, prion, or fungus that causes disease to its host.

The body contains many natural orders of defense against some of the common pathogens but if the immune system or “good” bacteria is damaged in any way  pathogenic bacteria can proliferate and cause harm to the host. Such cases are called opportunistic infection.

Types

Viral

Bacterial

Fungus

Parasites

Prions

Prions are abnormal proteins whose presence causes some diseases such as scrapie, bovine spongiform encephalopathy (mad cow disease) and Creutzfeldt–Jakob disease

A pathogen can be transmitted through various routes, which differ in different pathogens.

Palmar erythema is bright red warm palms. The thenar and hypothenar eminences and soles of feet are especially erythematous. The erythema blanches on pressure.

Causes:

1. Cirrhosis
2. In alcoholics
3. Viral hepatitis
4. Thyrotoxicosis
5. Rheumatoid arthritis
6. Leukemias
7. Pregnancy
8. Febrile diseases
9. Familial