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Biomedical subjects

R P Kumar

Publications and source records attributed to R P Kumar.

At least 19 recordsLinked to original sources
PubMed2000

Thermodynamics of interaction of caffeic acid and quinic acid with multisubunit proteins.

Helianthinin is a multisubunit protein from Sunflower seeds. Caffeic acid (CA) and quinic acid (QA) are intrinsic ligands present in sunflower seeds. The mechanism of interaction of these ligands with multisubunit proteins is limited. The present study enables one to understand the mechanism of the interaction of these ligands with the protein helianthinin. From this study, it is shown that CA has two classes of binding sites on helianthinin. The high-affinity class of sites total six from 60+/-10 for both high-affinity and low-affinity sites. Tryptophan, tyrosine and lysine residues of the protein are mainly involved in the interaction with CA. The temperature dependence of the binding in the range 10-45 degrees C can be clearly described by an enthalpy-entropy compensation effect at the low-affinity class of sites, while it is described by positive DeltaC(p)(o) at the high-affinity class of sites. This positive DeltaC(p)(o) has a contribution to the protein stability. The binding strength of CA also has a positive cooperativity at higher protein concentration. QA has two classes of binding sites on the protein based on the strength of the interaction. The interaction of QA with the protein is predominantly described by positive DeltaC(p)(o) for both classes of affinity. This suggests predominance of ionic/hydrogen bonding in the interaction process. Differential scanning calorimetric measurements reveal that the binding of both CA and QA induces destabilisation of the subunit-subunit interaction. Human methaemoglobin (mHb) has two binding sites on the molecule for CA. Both CA and QA decrease the stability of mHb, as indicated by decreased T(m). This destabilisation is also accompanied by dissociation to the monomers with concomitant conformational changes.

2S Albumins, Plant↗
PubMed1997

Changes in protein metabolism in hemolymph and fat body of the silkworm, Bombyx mori (Lepidoptera: Bombycidae) in response to organophosphorus insecticides toxicity.

Changes in protein metabolism were studied in hemolymph and fat body of 5th instar silkworm Bombyx mori exposed to lethal and sublethal doses of fenitrothion and ethion. The total protein content indicated a depletion followed by a concomitant increase in accumulation of free amino acids. Concurrently, the activity of protease in both of the tissues was also increased. A sharp enhancement in the activities of alanine aminotransferase and aspartate aminotransferase paralleled the elevation of glutamate dehydrogenase activity in the tissues studied. All these changes clearly documented the induction of severe proteolysis and transamination of amino acids.

Alanine Transaminase↗
PubMed1994

Changes in Na and K ions in mouse liver following in vivo exposure to ultrasound.

Mouse liver was exposed in vivo to a continuous and unfocussed ultrasound of 875 KHz at 5, 10 or 15 W/cm2 for 300 sec spread over five days and excised on day 0, 1, 5 and 10 for studying the changes in Na+ and K+ reserves and Na-K-ATPase activity. At 5 and 10 W intensities the change in ionic concentrations and Na-K-ATPase activity were almost in linear. At 15 W intensity the loss of both the ions and suppression of Na-K-ATPase indicated the damage of hepatic tissue caused by high intensity ultrasound. By day 10, all the animals of three exposures showed a normal ionic concentration with an optimum Na-K-ATPase activity in liver indicating the recovery process. The results indicate that ultrasound induces permeability changes in a glandular tissue exposed in vivo.

Animals↗
PubMed1993

Ultrasound-induced enhancement of ACh, AChE and GABA in fetal brain tissue of mouse.

Pregnant mice were exposed to continuous-wave (CW) ultrasound of 875 kHz frequency at 1 W/cm2 for 300 and 400 s, spread over five days, starting from the sixth day of pregnancy. The neurotransmitters, acetylcholine (ACh) and gamma amino butyric acid (GABA), and the associated enzyme acetylcholinesterase (AChE) levels, were estimated in the exposed fetal brains. Enhanced levels, significant at p < 0.001, were observed in the brains excised on day 10, day 15 and day 20 of gestation compared to sham-exposed and cage-control brains.

Acetylcholine↗
PubMed1992

Some biochemical changes in mouse after in-vivo irradiation of pancreas with ultrasound.

875 KHz continuous wave of ultrasound at 2.5 W/Cm2 intensity revealed certain biochemical and enzymological changes in mouse pancreas and liver following the irradiation of pancreas in-vivo for a total of 300 seconds spread over five days. The sacrifice of the animals was carried out on day 0, day 1, day 5 and day 10. Blood glucose was reduced significantly with concomitant increase in liver glycogen. Glucose-6-phosphatase in liver was decreased significantly while glycogen phosphorylase showed marginal variations. Increased calcium pool in pancreas along with Ca2+ activated ATPase was observed. These alterations were prevalent in all the days of sacrifice and also for more than 10 days after the last exposure. The results are suggestive of ultrasound could stimulate the release of pancreatic secretions.

Animals↗
PubMed1991

Enzymatic studies in foetal brain and liver of mouse following in utero exposure to ultrasound.

Lactate, malate and succinate dehydrogenases (LDH, MDH and SDH) were estimated in the foetal brain and liver following in utero exposure of mice to a continuous wave of unfocussed ultrasound. Enzymes in both tissues showed a significant increase (P greater than 0.001), indicating high energy demand due to depletion of oxygen. The increase was recorded even on the twentieth day of pregnancy.

Animals↗
PubMed1991

Transmission of health information on leprosy from children to their families: another approach to health education.

A controlled study was carried out in the North Arcot District of Tamil Nadu, South India to determine whether health information given to schoolchildren would influence the knowledge and attitudes of their families concerning leprosy. A total of 41 children and almost all of their household members participated in the study. The study, conducted by questionnaire, involved a pre-test of knowledge and attitude about leprosy of seventh standard students and their families. After one group of children received health education about leprosy and the other received information about tuberculosis, an identical post-test questionnaire was administered to all participants. Although significant improvement in knowledge about leprosy was detected in the leprosy educated group of children compared with controls, no transmission of information on leprosy was detected in the family members of either group. The attitudes of the children who had been educated about leprosy may have been adversely affected by the health education session. The reasons for our failure to detect significant transfer of information about leprosy in this setting are discussed, as well as the need for additional research in this area.

Adolescent↗
PubMed1990

The need for a drug abuse documentation center in India.

The problems of alcoholism and drug addiction are major concerns in India. Alcohol and drugs were used in the past to obtain relief from pain and misery and to attain a state of forgetfulness. India is presently facing the problem of increased trafficking in drugs; heroin and hashish are supplied to the west through the subcontinent. Addiction has become a major problem in metropolitan centers. The Ministry of Welfare is responsible for drug abuse prevention programs and the rehabilitation of addicts. The Ministry of Health and Family Welfare is concerned with drug treatment. A deaddiction center, established at the All India Institute of Medical Sciences, became operational in 1988; it is responsible for health manpower training, research, and documentation. India has witnessed an exponential growth in the literature on drug abuse; it is no longer possible for a single library to acquire all of the international literature. There is a clear need to establish a drug abuse information center in India. This paper describes the aims, objectives, and planning for such a center and recommends the establishment of a national center in New Delhi with regional centers in other geographic areas.

Databases, Bibliographic↗
PubMed1989

Ultrasound induced damages and time bound recovery in mouse liver.

Therapeutic ultrasound at 875 kHz at 10 and 15 W/cm2 intensity induced extensive damages in the liver of mouse. Total exposure of 5 min was spread over 5 days. Aqueous medium was avoided by coupling the transducer directly to the skin surface. Mild to extensive damages were noted. Complete distortion of hepatocellular architecture was noted in 15 W irradiated mice. However, there was almost complete recovery by 10th day following the last exposure.

Animals↗