Effect of selective monoamine oxidase A and B inhibitors on footshock induced aggression in paired rats

Effects of a selective monoamine oxidase (MAO)--A inhibitor, clorgyline, a selective MAO-B inhibitor, deprenyl, and a non-selective MAO inhibitor, nialamide, were investigated on footshock-induced aggression (FIA) in paired rats. The doses and pretreatment times of the inhibitors used were based on an earlier reported in vivo dose-response and time-course study. In addition, apomorphine, a dopaminergic receptor agonist, and beta-phenylethylamine, a preferred substrate for MAO-B, were also used to garner corroborative evidence. The results of the study indicate that selective MAO-A inhibitors are likely to attenuate FIA by augmenting central serotonergic activity, while selective MAO-B inhibitors accentuate the behaviour by facilitating dopaminergic activity. A permissive role for noradrenaline could not be delineated by the available data.     

Effect of retinoic acid on adenosine diphosphate and collagen-induced alterations in enzymes of GSH-linked antioxidant defence system of human blood platelets in vitro

Collagen stimulation of blood platelets resulted in significant increases in malondialdehyde (MDA) formation and activity of glucose-6-phosphate dehydrogenase (G6PDH) and a decrease in catalase and glutathione peroxidase (GPx). Retinoic acid (RA) pretreatment did not show any appreciable changes except for a decrease in G6PDH activity as compared with collagen alone. RA pretreatment of human blood platelets resulted in an increase in the activities of catalase and GPx, two important radical scavenging enzymes, with significant decrease in MDA formation when compared with ADP alone. It is suggested that RA has a significant effect on the antioxidant defence system in ADP stimulated platelets but not in the collagen stimulated platelets.     

Differential effect of retinoic acid on ADP and collagen induced platelet aggregation

Retinoic acid (RA) was found to inhibit ADP induced but not collagen induced aggregation of human platelets and the differential action is related to intraplatelet Ca2+ reflux. RA was active at concentrations as low as 10(-7) M and required 20 min prior incubation with platelet suspension in order to inhibit aggregation by ADP. All the steps in ADP induced but not collagen induced platelet activation, viz. hydrolysis of phosphatidyl inositol, phosphorylation of 20, 47 and 250 kDa proteins as well as increased association of actin with Triton X-100 insoluble cytoskeletal matrix were inhibited by RA. RA when used as an agent for differentiation induction of cell progenitor is likely to affect the platelet aggregation and thereby the haemostatic process.     

Acute effects of heat on neuropsychological changes and physiological responses under noise condition

To examine the effects of heat and noise individually and jointly on certain physiological responses and cognitive and neuromotor based functions, 12 male participants were tested under 6 experimental conditions which resulted by combining 3 levels of heat (25 degrees, 30 degrees and 35 degrees C) and 2 levels of white noise (70 and 100 dB). The experiment was carried out in a controlled climatic chamber following two 6 x 6 latin square designs. The results indicated elevations in heart rate, oxygen uptake and body temperature due to the independent effect of heat or the combined effects of heat and noise. The independent action of noise was found to be depressive on the first two responses. On the neuropsychological effects, the heat adversely affected the speed in card sorting (by design configuration) and digit symbol tests, and also the accuracy and error rate in the reasoning ability test. The noise caused performance improvements in critical flicker frequency (simultaneous) and in error rates in card sorting (by design configuration). The combined effects of heat and noise indicated higher error rates in card sorting (by face value), decreased accuracy in reasoning ability and improvements in performance in accuracy scores and error rates in digit symbol test.     

Purification and properties of d-galactose-binding lectins from some erythrina species: Comparison of properties of lectins from E. indica,E. arborescens,E. suberosa, and E. lithosperma

The lectins of the seeds of four species of the genus Erythrina, namely E. indica, E. arborescens, E. lithosperma, and E. suberosa were isolated by affinity chromatography on acid-treated ECD-Sepharose 6B. The lectins were found homogeneous in polyacrylamide gel electrophoresis and immunochemical tests. In SDS-gel electrophoresis, E. indica and E. lithosperma lectins each gave two bands with subunit molecular weights of 30,000 and 33,000 in the case of the former and 26,000 and 28,000 in the case of the latter. E. arborescens and E. suberosa gave single bands corresponding to polypetide chain molecular weight of 28,000. The lectins were found to be glycoproteins with their neutral sugar contents ranging from 4–9%. In carbohydrate specificity all the lectins were d-galactose specific. Their close similarity was also demonstrated by their homologous cross-reaction against the antiserum to E. indica lectin. In hemagglutinating activity toward human erythrocytes, E. indica and E. suberosa lectins showed higher activity toward the O group and E. arborescens toward the B group. The results show the similarity of the lectins derived from different species of the same genus in respect of immunochemical properties and carbohydrate specificity. In studies on E. indica lectin, the protein was found homogeneous by electrophoretic, immunochemical, and sedimentation experiments. Its molecular weight of 68,000 determined from sedimentation and diffusion data indicated that the molecule was a dimer of two noncovalently bound unequal subunits whose SDS-gel electrophoretic molecular weights are noted above. The lectin was devoid of cysteine and methionine and contained valine as its N-terminal amino acid. It had 9% neutral sugars and 1.5% glucosamine. Equilibrium dialysis studies with lactose showed that the values of the association constant K at different temperatures were of similar orders of magnitude to other lectins and the dimeric molecule possessed two noninteracting binding sites.     

Steroid hormone effects on growth and apical dominance of sunflower

External application of estradiol-17β increased shoot growth but decreased root growth of sunflower seedlings. It completely inhibited cotyledonary axillary bud development in decapitated plants at the concentration of 1 μg/plant. Concentrations lower than this promoted cotyledonary axillary bud formation. Testosterone on the other hand inhibited both shoot and root growth and promoted cotyledonary axillary bud formation at all the concentrations used. Progesterone at high (0.25,μg/plant) concentration promoted shoot growth but inhibited root growth. A low concentration (0.1 μg/plant) of progesterone produced the opposite effect.     

Thyroid hormone regulation of prolactin binding to mouse mammary glands.

Membranes from mammary glands of mildly hypothyroid mice show a 70–85% reduction in prolactin binding while those from hyperthyroid mice bound 66% more prolactin compared to similar preparations from euthyroid animals. The prolactin binding data for mammary glands correlate well with the ability of the tissue from animals in various thyroid states to respond to prolactin $\text{in}\text{vitro}$ with increased lactose synthetase activity. Binding of prolactin to mammary membranes is enhanced when explants from mid-pregnant mice are cultured overnight in the presence of insulin, hydrocortisone and 10^?9 M L-T₃. This enhancement is not blocked by puromycin. These data suggest that thyroid hormones control the level of prolactin binding in mouse mammary tissue. This may be accomplished, at least in part, by activation of preexisting receptor molecules.     

Epidemiological studies on jute diseases

Summary Hyphae of M. phaseoli failed to grow on unsterilized natural soil and were completely lysed within 4 days of exposure. Germination of sclerotia in natural soil was inhibited indicating soil fungistasis. Lysis of mycelium and inhibition of germination of sclerotia could be annulled by addition of various organic nutrients and fertilizers to natural soil or by autoclaving the soil. Germination of dormant sclerotia in natural soil was stimulated by root-exudates of host and non-host plants. Population of sclerotia buried in unsterilized natural soil gradually declined and after 15 months only 35 per cent of the initial number could be recovered; more than 80 per cent of these germinated when nutrients were added. Data suggest poor saprophytic ability of M. phaseoli in mycelial form and the involvement of dormant sclerotia in the survival of the organism in soil.