Search PubMed⌕ Search

Biomedical subjects

V Kumar

Publications and source records attributed to V Kumar.

At least 361 records · Page 20Linked to original sources
PubMed1993

Childhood lichen planus (LP).

In adults, lichen planus (LP) is relatively more common than in children. Among 222 cases of LP, there were 25 (11.2%) children in our study. The majority of the cases were females in the age group of 8-14; the youngest child was 3 years old. Papular and linear types of LP were common in children. There was no familial history of LP in any of the cases. The patients with classic LP lesions responded well to dapsone therapy. This study supports the suggestion of Ramsay and Hurley that childhood LP is more common in the tropics.

Adolescent↗
PubMed1993

Effects of excitatory amino acid receptor agonists and antagonists on the secretion of melatonin, luteinizing hormone and prolactin in the ram.

To assess the role of excitatory amino acids (EAA) as neurotransmitters in the transmission of light information from the retina to the pineal gland, we have determined whether the systemic injection of EAA agonists in Soay rams will mimic the suppressive effect of light on the secretion of melatonin, and whether pretreatment of rams with EAA antagonists will block this effect. In addition, the efficacy of the drugs in affecting neuroendocrine systems was investigated by measuring the changes in the secretion of luteinizing hormone (LH) and prolactin. Injections fo the EAA receptor agonist, NMDA (N-methyl-D,L-aspartate: 4.0 mg/kg iv), and the non-NMDA type EAA receptor agonist, AMPA (DL-alpha-amino-3-hydroxy-5-methylisoxazole-propionic acid: 0.2 mg/kg iv) given at night to rams exposed to long days (16 h light: 8 h darkness), caused no change in the blood plasma concentrations of melatonin. The treatments induced an acute increase in the concentrations of LH, and NMDA, but not AMPA, caused a sustained increase in the concentrations of prolactin. Injections of the specific NMDA-type receptor antagonist, CGP (CGP 37849: 1.0 mg/kg iv) and the non-NMDA-type receptor antagonist, DNQX (6,7 Dinitroquinoxaline-2,3-dione: 0.5 mg/kg iv), given prior to a 1-h light period at night, in rams under long days, caused no change in the light-induced decrease in blood plasma concentrations of melatonin. The drug treatments had no effect on the plasma concentrations of LH, but CGP, and not DNQX, stimulated an acute increase in the plasma concentrations of prolactin. These results provide support for the hypothesis that EAA mechanisms operate in the hypothalamus to regulate the release of peptides and catecholamines which control the secretion of LH and prolactin from the pituitary gland; different sub-types of EAA receptors are involved in the control of the two pituitary hormones. The failure of the treatments to affect the secretion of melatonin may indicate that EAA receptor activation is not involved in the photic relay to the pineal gland, or may merely reflect the inability of the drugs to penetrate into the retina/SCN/pineal neural circuits to produce a response.

2-Amino-5-phosphonovalerate↗
PubMed1993

The circadian nature of melatonin secretion in Japanese quail (Coturnix coturnix japonica).

Plasma melatonin concentrations were measured in Japanese quail held under different photoperiods and constant darkness (< 1 lux). When subjected to LD6:18 (6 hr light: 18 hr darkness), levels rose approximately 2 hr after lights-off, attained a peak level 8 hr after lights off, and subsequently declined to low daytime levels before the next lights-on signal. This generated a distinct daily rhythm in melatonin secretion with a duration of approximately 13 h. On exposing quail to a range of photoperiods, containing 6, 9, 11, 12, 13, 15, 18, or 20 hr of light per day, the onset of melatonin secretion remained essentially similar with the rise occurring soon after lights-off. However, the offset of melatonin secretion was suppressed by the light of the next day and thus a much truncated rhythm was produced under long (> 12 hr) photoperiods. Importantly, between night lengths of 4 to 18 hr (i.e., LD 20:4 to LD 6:18) a linear relationship existed between the duration of night-length and secretion of melatonin with the duration increasing by about 0.8 hr for each additional hour of darkness. If quail were released into darkness following a short (LD 6:18) or long (LD 20:4) day schedule, the rhythm persisted for at least two cycles with peaks occurring at about 24 hr intervals. In those quail coming into darkness from long days (LD 20:4), the rhythm of melatonin secretion decompressed rapidly on both sides of the peak, indicating that both the onset and offset of melatonin secretion were suppressed under long days.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Synovial schistosomiasis of the hip.

Schistosomiasis is a common parasitic infestation in Egypt. We describe the case of a 24-year-old Egyptian man who presented with the signs of acute septic arthritis of the hip and in whom biopsy subsequently revealed schistosome ova in the synovium.

Adult↗
PubMed1993

Association of two esterase genes, a chromosomal inversion, and susceptibility to Plasmodium cynomolgi in the African malaria vector Anopheles gambiae.

The ability of a selected strain of the malaria vector Anopheles gambiae to encapsulate the early oocysts of the malaria parasite Plasmodium cynomolgi B has previously been shown to be genetically linked to specific esterase phenotypes. This association between Plasmodium susceptibility and esterase phenotype is found in the An. gambiae G3 strain from which the Plasmodium-refractory and -susceptible mosquito strains were derived. Genetic crosses had suggested that the esterase phenotypes reflect the assortment of two alleles at one esterase genetic locus, with the two esterase homozygotes showing Plasmodium-susceptible and -refractory phenotypes and the esterase heterozygote being intermediate in susceptibility. By using a variety of specific esterase inhibitors in conjunction with esterase staining of gel-electrophoresed mosquito homogenates, we found that the bands previously thought to reflect one genetic locus are actually the product of two different esterase loci, Est1, a cholinesterase, and Est2, a carboxylesterase. In addition, examination of chromosomal inversions and the esterase phenotype in the An. gambiae G3 strain revealed that different forms of a polymorphic inversion on the left arm of chromosome two (the 2La inversion) are inseparably associated with different alleles at these two esterase loci. We conclude that the genetic association among the esterase-linked Plasmodium-susceptibility locus and the two esterase loci is maintained by the suppression of recombination in 2La inversion heterozygotes in the An. gambiae G3 strain and its selected derivatives.

Alleles↗
PubMed1993

Anaesthetic steroids--a review.

Steroids produce anaesthesia besides producing the well known metabolic and hormonal effects. A number of anaesthetic steroids have been synthesized and tried clinically. Hydroxydione, althesin, minaxolone and pregnanolone are among those studied in detail. They act through GABAergic mechanism and are known to be advantageous over barbiturates.

Alfaxalone Alfadolone Mixture↗
PubMed1993

An epidemic of encephalitis in Haryana: serological evidence of Japanese encephalitis in a few patients.

An epidemic of encephalitis occurred in the eastern, paddy growing districts of Haryana state between July and November 1990. One hundred and eighty-two patients with encephalitis were admitted to different hospitals in Haryana and 118 of them expired (mortality rate 64.8%); 88% of the patients were children. The male to female ratio was 2. 3. 1. IgM class of antibodies to Japanese Encephalitis (JE) Virus could be demonstrated in the CSF and/or sera of 3 surviving and 2 fatal patients of the 19 patients studied. This is the first detailed report on an epidemic of encephalitis in North-Western part of India. Serologically proven cases of JE are being reported, for the first time, from this region.

Adolescent↗
PubMed1993

Evaluation of the home-based maternal record: a WHO collaborative study.

Thirteen centres in eight countries (Egypt, India, Pakistan, Philippines, Senegal, Sri Lanka, Democratic Yemen and Zambia) participated in the WHO collaborative study to evaluate the home-based maternal record (HBMR). The evaluation showed that use of the HBMR had a favourable impact on utilization of health care services and continuity of the health care of women during their reproductive period. When adapted to local risk conditions, their cut-off points and the available resources, the HBMR succeeded in promoting self-care by mothers and their families and in enhancing the timely identification of at-risk cases that needed referral and special care. The introduction of the HBMR increased the diagnosis and referral of at-risk pregnant women and newborn infants, improved family planning and health education, led to an increase in tetanus toxoid immunization, and provided a means of collecting health information in the community. The HBMR was liked by mothers, community health workers and other health care personnel because, by using it, the mothers became more involved in looking after their own health and that of their babies. Apart from local adaptation of the HBMR, the training and involvement of health personnel (including those at the second and tertiary levels) from the start of the HBMR scheme influenced its success in promoting maternal and child health care. It also improved the collection of community-based data and the linking of referral networks.

Continuity of Patient Care↗
PubMed1993

On-table pneumoperitoneum in the management of complicated incisional hernias.

'On-table' pneumoperitoneum before repair of 'complicated' incisional hernias has been used in eight patients considered to be at high risk of recurrence. In four patients the procedure revealed the presence of occult defects. The procedure was uncomplicated and a primary repair without the need for a prosthetic implant was possible in all cases. Six patients remain well with no sign of recurrence at a median follow-up of 96 months (range 22-120 months). Two patients died from conditions unrelated to the method of repair; acute necrotising pancreatitis on the 10th postoperative day and lobar pneumonia 2 months postoperatively. Peroperative pneumoperitoneum is a simple procedure which obviates the need for a prosthetic implant in selected patients. It is therefore particularly useful in the management of incisional hernias associated with sepsis, stomas or in patients requiring synchronous bowel resection.

Aged↗
PubMed1993

Action of oxygen free radical scavengers and inhibitors on the chemiluminescence response of monocytes and neutrophils in rheumatic fever.

Various scavengers of oxygen free radicals or inhibitors of their production were used to measure the relative amounts of oxygen free radicals generated in phagocytic cells. The agents used were iodoacetate, superoxide dismutase, sodium benzoate, catalase and mannitol. The studies were made in patients with a recurrence of rheumatic activity, chronic rheumatic heart disease or pharyngitis, and in normal controls. Monocytes and neutrophils of the subjects were stimulated with latex in the presence or absence of a scavenger/inhibitor and the per cent inhibition of the chemiluminescence response was calculated. There were 10 patients in each group. Follow-up studies were done at 15 days, 3 months and 6 months. In the patients with a recurrence of rheumatic activity, the level of oxygen free radicals generated in the initial study was so high that the scavenger/inhibitors were able to reduce the chemiluminescence only in part. The diminution in chemiluminescence increased during the follow-up period. In the patients with chronic rheumatic heart disease, the per cent inhibition of the chemiluminescence response was significantly higher in the initial study than that observed in patients with a recurrence of rheumatic activity, and it remained constant during the follow-up period. The scavenger/inhibitors were almost completely able to inhibit the generation of oxygen free radicals in patients with pharyngitis and in normal controls.

Female↗
PubMed1992

Donor-type activated natural killer cells promote marrow engraftment and B cell development during allogeneic bone marrow transplantation.

Purified NK cells were obtained from mice with severe combined immune deficiency and were activated with human IL-2 (hrIL-2) in vitro to determine if, once activated, these cells could be transferred with compatible bone marrow cells (BMC) and promote marrow engraftment in irradiated allogeneic recipients. After culture with hrIL-2, these cells maintained a phenotypic and lytic spectrum consistent with a pure population of activated NK cells. These activated NK cells were then adoptively transferred with the donor BMC and rhIL-2 into lethally irradiated allogeneic hosts. The addition of NK cells with the BMC allowed for more rapid hematopoietic engraftment as determined through short term studies, and greater donor-derived chimerism with accelerated reconstitution of the B cell population as determined with long term analysis. No evidence of graft-vs-host disease was detected in the recipients receiving the activated NK cells with allogeneic T cell replete BMC and hrIL-2. The mechanism by which the transferred NK cells improved BMC engraftment was at least partly through the abrogation of the host effector cell's ability to mediate resistance to the marrow graft. Thus, the administration of donor-type activated NK cells with BMC and hrIL-2 may significantly augment hematopoietic engraftment and immune reconstitution in the clinical setting of allogeneic BMT without giving rise to graft-vs-host disease.

Animals↗
PubMed1992

Synthesis and substance P receptor binding activity of androstano[3,2-b]pyrimido[1,2-a]benzimidazoles.

Several heterosteroids containing a dihydroethisterone skeleton were prepared and shown to displace substance P in a receptor binding assay. Further biochemical (kinetic and Scatchard analyses) and pharmacological evaluation (substance P-induced plasma extravasation and salivation in the rat) of a representative example in this series (5a) established that these compounds are competitive antagonists at the substance P receptor.

Androstanes↗
PubMed1992

Hepatitis B virus envelope epitopes: gene assembly and expression in Escherichia coli of an immunologically reactive novel multiple-epitope polypeptide 1 (MEP-1).

A novel synthetic 323-bp gene with the open reading frame of a multiple-epitope polypeptide has been assembled and cloned. The gene is engineered by contiguous alignment of selected epitopes and functional domains of the hepatitis B virus envelope proteins separated by pairs of glycine residues. High-level bacterial production of this 100-amino acid (approx. 10 kDa) protein has been achieved and the gene product is stable. ELISA and Western blot experiments using epitope-specific antisera confirm that the corresponding epitopes are present in the engineered protein.

Amino Acid Sequence↗
PubMed1992

Subjugation of dominant immunogenic determinants within a chimeric peptide.

The mechanism of immunodominance was investigated using chimeric peptides from mouse myelin basic protein consisting of the immunodominant I-Au-restricted Ac1-11, attached by a peptide bond to I-Eu-restricted 35-47. Our results indicate that this chimeric peptide and certain of its derivatives were excellent immunogens both in vitro and in vivo. Notably, on immunization with Ac1-11:35-47 or Ac1-11 (Ala4):35-47, the proliferative T cell responses to each of its component peptides were almost completely "subjugated" in favor of neo-determinants that are I-Eu restricted. Furthermore, each of 11 hybridomas derived after immunization with Ac1-11:35-47 had specificity for junctional neo-determinants and none could be stimulated to produce interleukin-2 from Ac1-11 or 35-47. Subjugation of the immunogenicity of the original determinants occurred regardless of their dominance when separate. It did not appear to result from non-availability of the original determinants because the chimeric peptide was able to induce neonatal tolerance to each of its constituents. These results indicate that in an overlapping multideterminant array, the dominant determinant is unpredictable from historical data about any of the components. Determinant choice, at any stage of processing, may be governed by competitive aspects of determinant capture in an environment where all components--antigen, major histocompatibility complex and T cell receptor--are available.

Amino Acid Sequence↗