HSV1 (Herpes Simplex Virus Type-1) is a member of the Herpes group of viruses, the Herpesviridiae, which includes the important human pathogens HSV2, CMV (Cytomegalovirus), Varicella zoster Virus, EBV (Epstein-Barr Virus), HSV6 and 7, and Kaposi's associated Herpes virus, HHV8 (Human Herpesvirus-8). Of these, HSV1 has been the most extensively studied. Human is the only natural host to HSV. The virus is spread by contact and the usual site for the implantation is skin or mucous membrane. Following an initial infection in epithelial cells, the virus spreads to neurons of sensory ganglia, where it becomes latent. The virus emerges sporadically from latency, causing recurrent mucocutaneous lesions. Reactivation of the latent genomes upon stress can lead to re-infection of[..]

A blister (bulla) is a bubble of fluid that forms beneath a thin layer of dead skin. The fluid is a mixture of water and proteins that oozes from injured tissue. Blisters most commonly form in response to a specific injury, such as a burn or irritation, and usually involve only the topmost layers of skin. These blisters heal quickly, usually without leaving a scar. Blisters that develop as part of a systemic (bodywide) disease may start in the deeper layers of the skin and cover widespread areas. These blisters heal more slowly and may leave scars. Blistering disease is widely divided in to two catagories: Autoimmune blistering disease and inherited blistering disease. Autoimmune blistering diseases are a group of disorders in which the body mistakenly attacks healthy[..]

Stem Cells are undifferentiated cells that can give rise to several lineages of differentiated cell types. They are the founder cells for every organ, tissue and cell in the body. Stem cells are characterized by the ability to self-renew and maintain Pluripotency. These features allow Stem Cells to fulfill their multiple functions, namely to provide enough cells during organogenesis, to control tissue homeostasis and, in addition, to ensure regeneration and repair. ESCs (Embryonic Stem Cells) are derived from the ICM (Inner Cell Mass) of the developing Blastocysts, multicellular structures originating from four (Human) to five (Mouse) cleavages of fertilized oocytes. In Human, the fertilization of an Egg by a Sperm generates a Zygote that thirty hours later begins to[..]

The Proper functioning of a cell requires careful control of the levels of important structural proteins, enzymes, and regulatory proteins. Protein molecules are continuously synthesised and degraded in all living organisms. The concentration of individual cellular proteins is determined by a balance between the rates of synthesis and degradation, which in turn are controlled by a series of regulated biochemical mechanisms. Differences in the rates of protein synthesis and breakdown result in cellular and tissue atrophy (loss of proteins from cells) and hypertrophy (increase in protein content of cells). Precise control of protein turnover is, therefore, essential to cellular survival. The only way that cells can reduce the excessive level of a particular protein is by[..]

The Rho family of small GTP-binding proteins comprises a group of signaling molecules that are activated by a variety of Growth factors, Cytokines, Adhesion molecules, Hormones, Integrins, G-proteins and other biologically active substances and regulate a wide range of biological processes, including Reorganization of the Actin Cytoskeleton, Transcriptional Regulation, Vesicle Trafficking, Morphogenesis, Neutrophil activation, Phagocytosis and activation of the NADPH Oxidase, Mitogenesis, Apoptosis and Tumorigenesis. The mammalian Rho GTPase family currently consists of three subfamilies, Rho (RhoA, RhoB and RhoC), Rac (Rac1, Rac2 and Rac3) and CDC42 (Cell Division Cycle-42) (CDC42Hs and G25K). The best-characterized family members of Rho Family GTPase are RhoA, Rac1[..]

Epithelia in multicellular organisms constitute the frontier that separates the individual from the environment. Epithelia are sites of exchange as well as barriers, for the transit of ions and molecules from and into the organism. Epithelial cells achieve this by providing cellular borders that cover external and internal surfaces throughout the body. Complexes between adjacent cells include Gap Junctions, Desmosomes, Adherens Junctions (AJs) and Tight Junctions (TJs). Such junctions are quite essential for the modulation of paracellular permeability in various epithelia. Vertebrate epithelial cells exhibit Tight Junctions that lie apical to Adherens Junctions. Tight Junctions have an organizing role in epithelial polarization and establish an apico-lateral barrier to[..]

T cell responses against tumors require the recognition of specific peptides derived from tumor antigens in association with MIC (MHC Class I Molecules) by CD81 T cells expressing TCRs (T Cell Receptors). Such response generates intracellular antigen processing which are highly selective and binds only to some of the numerous polymorphic MHC class I molecules and often-impaired expression of MHC class I on tumor cells. Human gamma delta T cells are MICA (MHC-Class-Ipolypeptide-Related sequence-A) and MICB (MHC-Class-Ipolypeptide-Related sequence-B), which are distantly related to MHC class I but are functionally distinct. These molecules have no role in the presentation of intracellular peptide antigens instead MICA and MICB are closely related and functionally[..]

An Embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination. In Humans, it is called an Embryo from the moment of Fertilization until the end of the 8th week of gestational age, whereafter it is instead called a Fetus. In organisms that reproduce sexually, once a Sperm fertilizes an Egg cell, the result is a cell called the Zygote. In animals, the development of the Zygote into an embryo proceeds through specific recognizable stages of Blastula, Gastrula, and Organogenesis. Little is known about the specific genes that regulate these early events or how interactions among cells or how cellular interactions with other factors in the three-dimensional environment of the[..]

Embryonic development is the generation of a multicellular organism from a single cell. During this process, tissues and organs are differentiated and positioned at different parts of the organism. In animals, Embryonic development consists of 4 stages: Cleavage, Patterning, Differentiation and Growth. Mammalian Cleavage is strikingly different from most other patterns of Embryonic cell division. The mammalian oocyte is released from the ovary and swept by the fimbriae into the oviduct. The mature oocyte is surrounded by a protective coat of noncellular material (made of extracellular matrix and glycoproteins), called the Zona pellucida. Fertilization occurs in the ampulla of the oviduct, a region close to the ovary. For fertilization to occur, a haploid sperm cell[..]

Vitamin-C (Ascorbate or Ascorbic Acid) is an essential water-soluble Vitamin, well known for its antiscorbutic and antioxidant functions in humans. Vitamin-C was first identified by virtue of the essential role it plays in Collagen modification, preventing the nutritional deficiency Scurvy. Vitamin-C acts as a cofactor for the P4H (Prolyl Hydroxylase) enzymes, which post-translationally modify Collagen and thereby increase the strength and elasticity of tissues. Vitamin-C reduces the metal ion prosthetic groups of many enzymes, thereby maintaining the activity of enzymes. The fact that prevention of Scurvy through modification of Collagen is the most obvious role for Vitamin-C it is not necessarily the only role of Vitamin-C (Ref.1). Collagen modification depends on[..]

Thrombin/TFIIa (Activated Factor-II) is a coagulation protein that has many effects in the Coagulation cascade, the homeostatic process of greatest interest. It is a multifunctional serine proteinase best known for its ability to cleave Fibrinogen to Fibrin. Fibrin forms an essential component of the Blood Clot. When a blood vessel is injured, bleeding is stopped by clotting factors which form a Thrombus/Clot of Fibrin threads that trap platelet aggregates. A clot is a jelly-like mass of thickened blood composed of Fibrin and platelet aggregates. The first step in clotting is adhesion of platelets, which are fragments of blood cells that circulate in the blood, to the cut edges of a damaged blood vessel. In this way, a platelet plug is formed and external bleeding[..]

The process by which the body prevents blood loss is referred to as coagulation. Thrombin/TFIIa (Activated Factor-II) is a multifunctional serine proteinase, which serves as an essential component of the process of Blood Coagulation - the hemostatic process of greatest interest. When a blood vessel is injured, bleeding is stopped by clotting (Coagulation) factors that form a thrombus (clot) of Fibrin threads which trap platelet aggregates and other blood cells. Clotting is a mechanism used by the body to stop bleeding. Our body needs to be able to clot blood as this is the normal way bleeding is stopped to begin the healing following an injury. The first step in clotting is adhesion of platelets, which are fragments of blood cells that circulate in the blood, to the[..]