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Biomedical subjects

S Khare

Publications and source records attributed to S Khare.

101 records · Page 6Linked to original sources
PubMed1975

Effect of informational load on human performance in a combined manual and decision task.

With the increased automation, the worker's role in the industry is changing. He is required to make use of his decision making as well as motor capabilities (Type II tasks). Production system designers and managers are required to predict and evaluate human performance. The techniques available are suitable for tasks involving manual motions. To obtain an insight of the human performance characteristics for Type II tasks, experimental investigations in which the informational load could be varied and the magnitude of manual motions could also be altered were undertaken. Five subjects were tested in a 3 x 2 completely randomized and full factorial experiment. The three levels of informational load were 1, 2 and 3 bits and two distances of manual motions were 7 inches and 14 inches. In addition to measuring performance times, heart rate and breathing rate of the subjects were also monitored. Performance time and heart rate difference were observed to increase as the informational load increased, while the distance was kept invariant. Breathing rate was not found to be a significant variable.

Adult↗
PubMedDate not supplied

Seroconversion following killed polio vaccine in neonates.

The study was carried out to evaluate the efficacy of IPV in neonates and to study the additive effect of IPV or OPV at birth on seroconversion with three subsequent doses of OPV. Addition of IPV or OPV at birth to the conventional OPV schedule resulted in significantly higher seroconversion rates than in the controls, who received three doses of OPV. Three doses of IPV beginning from birth resulted in significantly better seroconversion rates than in the control group. Children receiving 3 doses of IPV showed significantly greater seroconversion rates against type III polio virus than those receiving IPV/OPV at birth followed by 3 doses of OPV. The difference in the seroconversion rates against the other virus types was not significant. A significantly greater number of children who received some vaccine at birth (IPV or OPV) were protected against poliomyelitis by 6 weeks age as compared to those who received no immunization at birth. The study recommends that seroconversion rates following three doses of IPV are satisfactory. Addition of IPV or OPV at birth to the conventional schedule markedly increases the seroconversion rates. Immunization can be started at birth to ensure early protection against poliomyelitis.

Antibodies, Viral↗
PubMedDate not supplied

Oral polio vaccination in infants: beneficial effect of additional dose at birth.

This study was done to assess the response of newborns to trivalent oral polio vaccine and to study any efficacy of OPV if given to infants on third day of life. The study was conducted in two groups, A (87) and B (55) of infants in Delhi, India. In group A, the children received one birth dose or 'O' dose of TOPV, followed by 3 conventional doses started at 6 weeks, and in group B the children received only 3 doses of OPV. Pre and one month post immunization serum samples were tested for the presence of neutralising antibodies. In addition, in group A serum samples were collected at 6 weeks before the administration of 1st dose to see the sero response following 'O' dose of TOPV. It was found that administration of OPV on 3rd day of life leads to sero conversion in 15.3% of infants to all three polio virus types by the age of 6 weeks, and highest sero response was seen for polio virus type 1. Sero-conversion in group A was significantly more than sero-conversion in group B after the administration of last dose. Thus the study has established that immunization of newborns with TOPV is a safe and effective means for improving protection against the disease.

Antibodies, Viral↗
PubMedDate not supplied

Rapid effects of 1,25(OH)2 vitamin D3 on signal transduction systems in colonic cells.

Previous work from our laboratory demonstrated that 1,25(OH)2D3 rapidly stimulated hydrolysis of membrane polyphosphoinositides (PI) in rat colonocytes and in Caco-2 cells, generating the second messengers DAG and IP3. [Ca2+]i subsequently increased due to IP3-mediated release of intracellular Ca2+ stores, and to Ca2+ influx through a receptor-mediated Ca channel. Studies examining purified antipodal plasma membranes and experiments using Caco-2 cell monolayers found that 1,25(OH)2D3 influenced PI turnover only in the basolateral (BLM) and not brush border (BBM) membranes. Vitamin D analogues with poor affinity for the vitamin D receptor were found to effectively stimulate PI turnover, suggesting the presence of a unique vitamin D receptor in the BLM. Studies from our laboratory have demonstrated saturable, reversible binding of 1,25(OH)2 D3 to colonocyte BLM. Recently, we found that 1,25(OH)2D3 activated the tyrosine kinase c-src in colonocyte BLM by a heterotrimeric guanine nucleotide binding protein (G-protein)-dependent mechanism, with subsequent phosphorylation, translocation to the BLM, and activation of PI-specific phospholipase C gamma. Due to the rise in [Ca2+]i and DAG, two isoforms of protein kinase C (PKCalpha and PKCbeta2), but not other isoforms were activated by 1,25(OH)2D3 in rat colonocytes. Recent studies demonstrated that the seco-steroid translocated the beta2 isoform to the BLM, but not the BBM. In contrast, the alpha isoform did not translocate to either antipodal plasma membrane, but modulated IP3-mediated Ca2+ release from the endoplasmic reticulum. Preliminary studies have shown that 1,25(OH)2D3 also activated phosphatidylcholine phospholipase D (PLD) in Caco-2 cells, generating phosphatidic acid and contributing to the sustained rise in DAG. PLD stimulation occurred by both PKC-dependent and -independent mechanisms. Inhibitors of G-proteins, c-src, and PKC blunted the seco-steroid-mediated activation of PLD. Cells stably transfected with sense PKCalpha showed increased 1,25(OH)2D3-stimulated PLD activation, whereas transfectants with antisense PKCalpha had an attenuated response. In addition, 1,25(OH)2D3 also regulated PLD by activating the monomeric G-protein rho A by a mechanism independent of the G-protein/ c-src/PKC pathway.

Animals↗