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Biomedical subjects

V Kumar

Publications and source records attributed to V Kumar.

At least 667 records · Page 37Linked to original sources
PubMed1987

Recording of birth weight in a primary health care setting in India.

The feasibility of recording birth weights in two community development blocks in rural areas was tested for general application of the procedure in a Primary Health Care setting. During the four year study period, the birth weights were recorded in 1,919 babies in one block and 1,596 in the other with a success rate of 98%. Although the incidence was 22% in block A and 34% in block B, the mean birth weights were statistically similar (p = greater than 0.05). The mean birth weights and the weight ranges recorded by research staff and PHC workers were comparable. The adoption of a simple, technically feasible, inexpensive, culturally acceptable technique which is suitable for local conditions is recommended. This should be accomplished in a step-wise manner.

Attitude to Health↗
PubMed1987

Role of natural killer cells in resistance to Cryptococcus neoformans infections in mice.

Previous studies have suggested a possible role for natural killer (NK) cells in resistance to some fungal infections, including Cryptococcus neoformans infections. The role of NK cells in early clearance of C neoformans from tissues and in long-term survival was studied in mice following intravenous inoculations of the organism. Mice treated with anti-asialo GM1 antiserum to temporarily reduce NK activity demonstrated an increase in colony-forming units (CFU) of C neoformans in the lung 24 hours after an intravenous inoculation of the organism. CFU in liver, spleen, kidney, and brain were not different in anti-asialo GM1 antiserum-treated versus control mice. An NK-specific reagent, anti-NK 1.1 monoclonal antibody, was used to deplete mice of NK cells in vivo for at least 14 days without affecting other natural defenses. The number of C neoformans retained in the lungs 24 hours after inoculation of the organism was significantly greater in NK cell-depleted mice than in controls, although CFU in other organs were unaffected. Following the intravenous inoculation of C neoformans, the survival of anti-NK 1.1-treated mice was not different from control mice. The effect of NK cell activity on resistance to C neoformans was also determined after an intratracheal inoculation of the organism. Mice pretreated with anti-NK 1.1 demonstrated no increases in CFU in the lungs, spleen, or brain as compared with controls. These data indicate that NK cells can play a role in vivo in early resistance against C neoformans if the organism is delivered via the intravenous route. However, NK cells do not play a role in either determining survival after an intravenous inoculation nor in resistance during an infection acquired via the respiratory tract.

Animals↗
PubMed1986

The NK-1.1(-) mouse: a model to study differentiation of murine NK cells.

The NK-1.1(-) mouse was constructed by weekly injections of monoclonal anti-NK-1.1 antibody from birth through adulthood. Spleen cells from these mice have decreased NK-1.1+ cells and null (Thy-1- and B220-) cells. Their splenic NK activity to YAC targets was low and was not enhanced by IFN-alpha or IFN-beta. Bone marrow (BM) of these NK-1.1(-) mice have normal precursors to NK cells: 1) NK activity could be generated from NK-1.1(-) BM cells cultured in rIL 2 for 5 to 6 days. These cultured BM cells expressed Qa-5, Thy-1, AsGm-1, and NK-1.1 antigens. The precursor cells of these BM cytotoxic cells are NK-1.1-; 2) transfer of BM cells from the NK-1.1(-) mice reconstituted the NK activity of irradiated, NK-depleted recipients. Lymphokine-activated killer cells could also be generated from spleens of these NK-1.1(-) mice. Therefore, the NK-1.1(-) mice were specifically depleted of mature cytotoxic NK cells, but not the NK-1.1- precursors of NK cells. This mouse model is valuable to study ontogeny and physiologic relevance of NK cells.

Animals↗
PubMed1986

Murine natural killer cells do not express functional transcripts of the alpha-, beta-, or gamma-chain genes of the T cell receptor.

Murine natural killer (NK) cells were purified by sorting with the NK cell-specific monoclonal antibody anti-NK-1.1. Sorted NK-1.1+ cells contained all splenic NK activity and could be propagated in human recombinant IL 2 for 3 to 4 wk. Short-term cultured NK-1.1+ cells maintained the cell-surface phenotype, morphologic appearance, and lytic activity characteristic of freshly isolated splenic NK cells. RNA extracted from this purified and propagated population of NK cells was probed for T cell receptor gene transcripts by Northern blot analysis. No functional transcripts of the alpha-, beta-, or gamma-chain genes of the T cell receptor were detected. These data dissociate NK cells from mature cytotoxic T cells, as well as the earliest identifiable cells committed to the T lineage.

Animals↗
PubMed1986

Crystallization and preliminary data of Indian buffalo erythrocyte carbonic anhydrase.

The most abundant anhydrase isoenzyme from the erythrocyte of Indian buffalo has been purified using affinity gel and DEAE-cellulose ion-exchange columns and single crystals suitable for X-ray diffraction studies have been obtained. The unit cell dimensions are a = 46.8 A, b = 104.5 A, c = 60.4 A, beta = 91.2 degrees and the space group is P2(1), with two molecules per asymmetric unit.

Animals↗
PubMed1986

Origin and differentiation of natural killer cells. II. Functional and morphologic studies of purified NK-1.1+ cells.

Cells bearing the NK-specific marker NK-1.1 were purified from mouse spleens by utilizing a monoclonal anti-NK-1.1 antibody and cell sorting. In normal adult mice, all of the splenic NK activity against YAC-1 cells was found in the NK-1.1+ fraction, whereas NK-1.1- cells were depleted of NK activity. The NK activity of sorted NK-1.1+ cells was enriched 15- to 30-fold over unfractionated spleen cells. Light and electron microscopic studies of purified NK-1.1+ cells showed a homogeneous population of cells, each containing one to four cytoplasmic granules. Mice whose bone marrow has been destroyed by chronic exposure to 17-beta-estradiol have very low NK activity. However, spleen cells of estradiol-treated mice contained a normal frequency of NK-1.1+ cells which bound to YAC-1 cells, but failed to lyse them even after purification and subsequent exposure to interferon-alpha/beta in vitro. It appears, therefore, that in the absence of intact bone marrow, NK-1.1+ cells may be arrested in a nonlytic and interferon-unresponsive state. Spleens of neonatal mice which have low NK activity were analyzed to ascertain whether immature NK-1.1+ cells, similar to those found in estradiol-treated mice, could be demonstrated. Spleens of 8- to 9-day-old mice also contained NK-1.1+ cells which had very low NK activity even after purification. Sorted NK-1.1+ cells were examined for cytotoxicity in mice whose NK activity was suppressed by pretreatment with Corynebacterium parvum (-15 days). In contrast to cells from estradiol-treated and neonatal mice, NK-1.1+ from mice treated with C. parvum had normal functional activity. Similarly, although NK activity of unfractionated bone marrow cells is low, sorted NK-1.1+ cells were greatly enriched for lytic activity. Thus, we conclude that cell sorting with monoclonal anti-NK-1.1 antibody provides a powerful tool for examining the mechanisms underlying various states of low NK activity, and there exist NK-1.1+, nonlytic, interferon-unresponsive cells which apparently require an intact marrow microenvironment for differentiation into mature, lytic NK cells.

Animals↗
PubMed1986

Anti-endomysial antibodies. A serologic marker of dermatitis herpetiformis.

Direct immunofluorescence (IF) studies of skin biopsies are of value in the diagnosis of most, but not all, cases of dermatitis herpetiformis (DH). Similarly, histologic studies are of help but may be questionable or completely nonspecific. Serologic studies for the presence of IgA-class anti-endomysial antibodies are very specific and are found in 70% of patients with DH and in all untreated patients with celiac disease. The titers of these antibodies are directly associated with the degree of gut disease in these patients. Thus, the presence of these antibodies even in the absence of classic direct IF and histologic findings are diagnostically important. We encountered three cases in which both direct IF and histologic studies were equivocal toward confirming the clinical diagnosis of DH. Serologic studies for the presence of IgA-class anti-endomysial antibodies provided evidence for the diagnosis of DH, and, in each case, results were confirmed by further direct IF studies. Since these antibodies are disease specific for DH and celiac disease and are found in most active cases of DH, they may be considered an adjunct to the direct IF and histologic studies of the skin.

Aged↗
PubMed1986

Aqueous vs viscous phenylephrine. I. Systemic absorption and cardiovascular effects.

We studied 30 patients undergoing vitreoretinal surgery to compare the systemic absorption and cardiovascular effects of 2.5% aqueous and 2.5% viscous (21 cp) ophthalmic solutions of phenylephrine hydrochloride. No significant differences were noted in the plasma levels or changes in blood pressure between the two groups, although there was a tendency toward higher mean plasma levels and blood pressures in groups receiving 2.5% aqueous phenylephrine hydrochloride. Maximum plasma levels were achieved within the first 20 minutes following topical application of phenylephrine eye drops, irrespective of the nature of the vehicle. This finding emphasizes the importance of monitoring these patients, especially those at high risk for any adverse cardiovascular effects during the first 20 to 30 minutes following instillation of phenylephrine eye drops. The patients in our study were supine and under general anesthesia. Therefore, there was no effect by lid blinking, the lacrimal pump, or gravity, which would ordinarily increase absorption by the nasal mucosa through the nasolacrimal system. By eliminating these variable factors, such as lid blinking, the study was performed in a stable and controlled manner, but the results may not be directly applicable to an upright awake patient.

Adult↗
PubMed1986

Aqueous vs viscous phenylephrine. II. Mydriatic effects.

We performed four studies to determine whether there is a difference in the mydriatic effect of 2.5% aqueous vs 2.5% viscous phenylephrine hydrochloride solutions. The first study was performed under "room light" conditions, and the mean (+/- SD) dilation at one hour was 0.87 +/- 1.18 mm for the aqueous and 0.86 +/- 1.14 mm for the viscous solutions. The second study was performed in a darkened room, and the mean dilation at one hour was slightly greater than in room light but was still minimal (aqueous, 1.14 +/- 1.00 mm; viscous, 1.07 +/- 1.11 mm). In the third study, patients were pretreated with a topical anesthetic (0.5% proparacaine hydrochloride), and the mean one-hour dilation was approximately twice (aqueous, 2.30 +/- 0.81 mm; viscous, 2.41 +/- 0.88 mm) that found in patients who were not pretreated with proparacaine. In the fourth study, the two phenylephrine solutions were used in combination with 1% tropicamide, and the mean one-hour dilation was 3.8 +/- 0.82 mm for the aqueous and 3.8 +/- 0.98 mm for the viscous solutions. Our studies show that there is no difference in the mydriatic effect of 2.5% aqueous vs 2.5% viscous phenylephrine solutions when used alone or in combination with 0.5% proparacaine or 1% tropicamide.

Adult↗
PubMed1986

The chicken oestrogen receptor sequence: homology with v-erbA and the human oestrogen and glucocorticoid receptors.

A chicken oviduct cDNA clone containing the complete open reading frame of the oestrogen receptor (ER) has been isolated and sequenced. The mol. wt of the predicted 589-amino acid protein is approximately 66 kd which is very close to that of the human ER. Comparison of the human and chicken amino acid sequences shows that 80% of their amino acids are identical. There are three highly conserved regions; the second and third of which probably represent the DNA- and hormone-binding domains of the receptor. The putative DNA-binding domain is characterised by its high cysteine and basic amino acid content, and the hormone-binding domain by its overall hydrophobicity. These two domains of homology are also present in the human glucocorticoid receptor (GR) and the product of the avian erythroblastosis virus (AEV) gene, v-erbA, indicating that c-erbA, the cellular counterpart of v-erbA, belongs to a multigene family of transcriptional regulatory proteins which bind steroid-related ligands. The first highly conserved ER region is not present in the truncated v-erbA gene, but shares some homology with the N-terminal end of the GR. The function of the v-erbA gene product is discussed in relation to its homology with the ER and GR sequences.

Amino Acid Sequence↗
PubMed1986

Localisation of the oestradiol-binding and putative DNA-binding domains of the human oestrogen receptor.

Site-directed mutagenesis was used to prepare a series of human oestrogen receptor (hER) deletion mutants. The ability of these mutant receptors to bind oestradiol, either after being transiently expressed in HeLa cells or produced synthetically in vitro using T7 polymerase coupled with a rabbit reticulocyte lysate translation system, was analysed. The results indicate that a region which is highly conserved (94% amino acid identity) between the human and chicken ERs (region E) contains all of the sequence necessary to bind oestradiol with high affinity. When tight nuclear association of the oestradiol-receptor complex was investigated using the oestradiol-binding mutants of the same series, two regions of the hER sequence were found to be important. One of these regions is completely conserved (100% amino acid identity) between the human and chicken ERs (region C). This region is rich in cysteine and basic amino acids and contains motifs similar to those which have been proposed to be important for DNA binding in other eukaryotic transcriptional regulatory proteins. The other region (region D), which is comparatively poorly conserved (38% amino acid identity), is located between the putative DNA-binding domain (region C) and the oestradiol-binding domain (region E).

Animals↗