Polymeric nanoparticle formulation of Octapeptide (NP-OP): In vitro release and in vivo effect in common marmosets, Callithrix jacchus Linn.

yielded an average particle size of 120 nm with 70% encapsulation-efficiency. In vitro release profile of NP-OP showed sustained release of OP for 21 days. In vivo anti-fertility studies were conducted in marmosets. Results indicated that control animals conceived in the same cycle while two of three treated animals failed to conceive in treatment cycle. The in vivo studies thus corroborate with in vitro release of OP, demonstrating its anti-fertility activity in 66% of animals.

Immunoregulatory pathways in pregnancy.

Murine pregnancy is characterized by transient thymic atrophy and splenomegally. Several laboratories are investigating the immunoregulatory mechanisms during pregnancy, and the majority of these studies are primarily focused on the immunological changes either in the uterus or the thymus and not much information is available on the immunological changes in the spleen that result in transient splenomegally. An attempt has been made in this review to understand the significance of thymic atrophy, splenomegally and local immune changes in the uterus to understand the overall immunomodulatory mechanisms in pregnant mother. The most significant change which occurs soon after mating is the infiltration of immune cells such as macrophages and gammadelta-T cells into the uterus indicating that the mother's immune system detects the presence of foreign antigens in the reproductive tract. The sensitized cells appear to migrate to the secondary lymphoid organs including the spleen. The microenvironment in the spleen is conducive for the cell-cell contact and generation of immune response. The major changes that occur in the spleen are, the induction of T-cell dependent B-cell response on day-1 post-coitum (P.C.), generation of antibody producing B-cells on day-3 and also proliferation of CD8+ T-cells that peaks on day-3 of pregnancy. The weight of the spleen reaches a peak on day-10 in mice. Thereafter, on day-15 of pregnancy, lymphocyte apoptosis is seen in the spleen indicating the deletion of peripheral sensitized cells. This results in decrease in spleen weight to that of normal non-pregnant mice. The decrease in thymic weight after day-5 pregnancy was associated with the increased apoptosis of cortical thymocytes. This perhaps is due to negative selection of self-reactive thymocytes. Our studies have demonstrated that the pregnancy associated monoclonal antibodies react with antigens of sperm indicating that the mother's immune system recognizes and responds to the constituents of the semen to produce non-precipitating asymmetric auto antibodies (NPAA) or blocking antibodies which have favourable effects on pregnancy. It is postulated that the mother's immune response could be directed to some antigens of sperm along with some conserved antigens such as heat shock proteins (HSP) that are present both in sperm and in the mother. It may be speculated that after the initial priming to some conserved antigens of sperm and due to the presence of similar antigens in the mother, these activated clones are eliminated both in the primary and secondary lymphoid organs to prevent autoimmunity in the mother during pregnancy.

Poverty among widows of Kinshasa, Congo.

The linkages between poverty and death in the family in a sector of the city of Kinshasa, capital of the Democratic Republic of Congo (previously Zaire) were studied. The poor people have been identified using 3 convergent norms, described in the Methods of Materials section, based on total expenditure, calorie consumption in food, and proportion of expenditure for food. Family histories were recorded to understand the difficult situation of widow-headed households identified within the sample area. The relationship between death in the family and poverty was bi-directional: on the one hand, death of the breadwinner can accelerate the level of poverty; and on the other, poverty conditions can result in further deaths in the family.

Apoptosis of rat decidual cells: site specific initiation and related biochemical changes.

The artificially induced rat deciduoma serves as a model to study cellular changes associated with implantation in the endometrium. The stromal cells differentiate to form two types of decidual cells and are restricted to specific anatomical sites of the uterus. Programmed cell death starts in the antimesometrial area and expression of glutathione-S-transferase, an antioxidant enzyme, enhances in these cells as the deciduoma enters the regressive phase. The enzyme activity is significantly high compared with that of mesometrial decidual cells. Similarly, lipid peroxide content of antimesometrial decidual cells is high during this phase. DNA fragmentation, a feature of cells undergoing programmed cell death, is initiated in the antimesometrial area during regression of deciduoma.

Investigation with chitosan-oxalate oxidase-catalase conjugate for degrading oxalate from hyperoxaluric rat chyme.

Enteric hyperoxaluria manifests due to hyperabsorption of dietary oxalate, secondary to a variety of chronic gastrointestinal disorders. The potential use of chitosan immobilized oxalate oxidase-catalase conjugate to deplete the oxalate content of food materials, while they are in the digestive tract has been evaluated by treating rat stomach chyme with such an enzyme preparation. Oxalate oxidase, obtained from beet stem, was adsorbed on chitosan along with catalase and then cross linked with glutaraldehyde to stabilize the derivative. This chemical modification of oxalate oxidase brought about a shift in its optimal pH from 4.2 to 3.8 with a marginal increase in its K(m). Compared to native enzyme, the modified oxalate oxidase exhibited increased storage stability, higher thermal stability and enhanced resistance to proteolytic digestion and heavy metal inactivation. These improved properties of the immobilized oxalate oxidase possibly render it suitable for oral administration under hyperoxaluric conditions.

Coimmobilization of D-amino acid oxidase and catalase by entrapment of Trigonopsis variabilis in radiation polymerised Polyacrylamide beads.

Trigonopsis variabilis induced for D-amino acid oxidase and catalase was immobilized by entrapment in Polyacrylamide beads obtained by radiation polymerisation. Permeabilization of the cells was found to be essential for optimal activity of the enzymes in free cells. However, the process of entrapment itself was found to eliminate the permeability barrier of cells immobilized in Polyacrylamide. The two enzymes exhibited a differential response on Polyacrylamide entrapment. Thus, D-amino acid oxidase activity was stabilized to heat inactivation whereas catalase in the same cells showed a destabilization on entrapment in Polyacrylamide. The coimmobilized enzyme preparation showed an operational half life of 7-9 days after which the D-amino acid oxidase activity remained stable at a value 35–40% of that of the initial activity for a study period of 3 weeks. Coimmobilization of MnO2 was not effective in enhancing the operational life of the enzyme preparation.

Characterisation of lactic dehydrogenase from Lactobacillus casei.

Lactic dehydrogenase from Lactobacillus casei ATCC 7469 has been purified to homogeneity by a two-step affinity chromatography procedure which gave an yield of 35%. The enzyme specifically catalysed the conversion of pyruvate to lactate. The enzyme was maximally active at pH 4·6, which was shifted to 5·4 in the presence of fructose 1,6-biphosphate. The enzyme had a molecular weight of 70,800 with two identical subunits, unlike the lactic dehydrogenase from other sources. Histidine and primary amino groups appeared to be involved in catalysis.