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Biomedical subjects

V Kumar

Publications and source records attributed to V Kumar.

At least 631 records · Page 35Linked to original sources
PubMed1987

T cell receptor genes do not rearrange or express functional transcripts in natural killer cells of scid mice.

The lineage of natural killer (NK) cells is poorly understood. To examine the relationship between NK cells and cells of the T lineage we have examined purified NK cells from a mutant mouse strain (scid) with severe combined immunodeficiency. Approximately 40% of the lymphoid cells in the spleens of scid mice expressed the NK-specific marker NK-2.1. All NK activity of the scid spleen cells could be accounted for by the NK-2.1+ population, similar to results obtained by using normal C57BL/6 X DBA/2 (B6D2F1) mice. Sorted NK-2.1+ cells proliferated in response to human recombinant interleukin 2 (r-IL 2) but not to concanavalin A (Con A), and were maintained in culture for 2 to 3 wk. Cultured NK-2.1+ cells displayed a cell surface phenotype (Asialo-GM1+, Thy-1.2+, L3T4-, Lyt-2-) and lytic activity similar to that described for freshly isolated NK cells of normal mice. Furthermore, T cell receptor (TCR) genes of the TCR-gamma and TCR-beta loci were in germline configuration, and no functional transcripts of TCR-gamma, TCR-beta, or TCR-alpha were detected. We propose that the expression of the TCR is not necessary for functional NK activity, and NK cells are distinct from both mature cytotoxic T lymphocytes and the earliest identifiable T cells.

Animals↗
PubMed1987

Antiendomysial antibody--useful serological indicator of dermatitis herpetiformis.

Antiendomysial antibodies (EmA) of the IgA class are directed against reticulin components of the primate smooth muscle and are markers of gluten-sensitive enteropathy. These antibodies occur in essentially all active cases of celiac disease and in about 70% of dermatitis herpetiformis (DH) patients. IgA deposits in the dermal papillae of the skin are the hallmark of DH and are employed routinely in establishing its diagnosis. The incidence of IgA deposits in skin varies depending upon the site and type of biopsy specimen taken. We studied sera and skin biopsy specimens for EmA and for IgA deposits in the skin from 11 DH patients. EmA were detected in the sera of 10 of the 11 cases. Of these 11 patients, 9 were positive for IgA deposits in their skin, as revealed by direct immunofluorescence (IF). The immune deposits were detected in the normal, and not in the lesional skin. DH cases that were initially negative on biopsy and serum positive for EmA were found to be positive when a repeat biopsy of the normal skin was performed. Thus, serological studies in conjunction with direct IF studies of the normal skin are useful in making a diagnosis of DH.

Adult↗
PubMed1987

Construction of cDNA libraries by blunt-end ligation: high-frequency cloning of long cDNAs from filamentous fungi.

A simplified cDNA synthesis and cloning method, suitable for efficient generation of cDNA libraries at frequencies up to 10(6) clones/micrograms mRNA, is described. Routine synthesis of transcripts of well over 4 kb is facilitated by the use of high-quality RNA template isolated from materials rich in RNases. Laborious cloning steps, like tailing or addition of linkers, can be omitted by the use of efficient blunt-end ligation to plasmid vectors, and rapid verification as well as characterization of the clones is possible by double-stranded plasmid sequencing. Using this method we have constructed several cDNA libraries of different filamentous fungi and show here the synthesis and cloning of cDNA copies larger than 1.8 kb corresponding to three Trichoderma reesei cellulases.

Bacteriophage lambda↗
PubMed1987

Effects of a subanesthetic concentration of nitrous oxide on establishment, elicitation, and semantic and phonemic generalization of classically conditioned skin conductance responses.

Classical conditioning of skin conductance responses was studied in 16 men and 16 women breathing 30% nitrous oxide or 100% oxygen to see how nitrous oxide affected establishment, elicitation, and generalization of conditioned responses (CRs). For CRs that had been established before gas inhalation, nitrous oxide blocked elicitation of "anticipatory" (long latency) but not "orienting" (short latency) CRs. Nitrous oxide appeared to prevent new CRs from being established during its inhalation, but learning evidently took place since anticipatory CRs could be elicited after nitrous oxide inhalation had ceased. Words were used as the conditioned stimuli and nitrous oxide altered generalization of CRs to other words related in meaning or sound, though generalization effects were limited. Nitrous oxide also seemed to reduce the efficacy of the unconditioned stimulus. The results were interpreted in terms of Rescorla's theory of classical conditioning.

Adult↗
PubMed1987

Effect of linear alkyl benzene sulfonate in skin of fish fingerlings (Cirrhina mrigala): observations with scanning electron microscope.

Pathomorphological changes in the skin was noticed under the scanning electron microscope in fish fingerlings (Cirrhina mrigala) exposed to 0.005 ppm (25% of the LC50) concentration to linear alkyl benzene sulfonate. The epithelial cells present in the epidermis of the skin were found to secrete more mucus with linear alkyl benzene sulfonate (LAS) than did controls. The presence or deposition of mucus on the surface of skin indicated likely molecular interaction between constituents of mucus and LAS.

Animals↗
PubMed1987

Suspected resistance of Ostertagia ostertagi in cattle to levamisole.

Observations on a beef cattle farm in Flanders led to the suspicion of resistance to levamisole in a strain of Ostertagia ostertagi. After treating a group of six animals with levamisole (5 mg kg-1 L.W., i.m.) the reduction in the number of trichostrongylid eggs per gram of faeces varied between 0 and 66.6%, whereas a similar group treated with fenbendazole (7.5 mg kg-1 L.W., p.o.) showed a reduction in worm burdens of 100%. Coproculture showed that the remaining eggs in the first treatment group were all Ostertagia sp. The suspected field strain was compared with a reference strain of O. ostertagi by means of the in vitro larval paralysis test. This test showed LC95 values of 9.12 micrograms ml-1 and of 99.04 micrograms ml-1 for the reference and the field strain respectively, which indicates a resistance factor for the latter of 10.9. These results were not unequivocally confirmed by the post mortem findings on a tracer calf necropsied 4 days after treatment with levamisole.

Animals↗
PubMed1987

Human complement C3b/C4b receptor (CR1) mRNA polymorphism that correlates with the CR1 allelic molecular weight polymorphism.

The human C3b/C4b receptor (CR1) is a Mr approximately equal to 200,000 single-chain integral membrane glycoprotein of human erythrocytes and leukocytes. It functions both as a receptor for C3b- and C4b-coated ligands and as a regulator of complement activation. Prior structural studies have defined an unusual molecular weight allelic polymorphism in which the allelic products differ in molecular weight by as much as 90,000. On peripheral blood cells there is codominant expression of CR1 gene products of Mr 190,000 (A), 220,000 (B), 160,000 (C), and 250,000 (D). Results of prior biosynthetic and tryptic peptide mapping experiments have suggested that the most likely basis for the allelic molecular weight differences is at the polypeptide level. In order to define further the molecular basis for these molecular weight differences, human CR1 was purified to homogeneity, tryptic peptide fragments were isolated by HPLC and sequenced, oligonucleotide probes were prepared, and a CR1 cDNA was identified. A subclone of this CR1 cDNA was used as a probe of RNA blots of Epstein-Barr virus-transformed cell lines expressing the allelic variants. Each allelic variant encodes two distinct transcripts. A mRNA size polymorphism was identified that correlated with the gene product molecular weight polymorphism. This finding, in addition to a prior report of several homologous repeats in CR1, is consistent with the hypothesis that the molecular weight polymorphism is determined at the genomic level and may have been generated by unequal crossing-over.

Alleles↗
PubMed1987

DNA sequence responsible for the amplification of adjacent genes.

A 10.3-kb DNA fragment in the 5'-flanking region of the rat prolactin (rPRL) gene was isolated from F1BGH(1)2C1, a strain of rat pituitary tumor cells (GH cells) that produces prolactin in response to 5-bromodeoxyuridine (BrdU). Following transfection and integration into genomic DNA of recipient mouse L cells, this DNA induced amplification of the adjacent thymidine kinase gene from Herpes simplex virus type 1 (HSV1TK). We confirmed the ability of this "Amplicon" sequence to induce amplification of other linked or unlinked genes in DNA-mediated gene transfer studies. When transferred into the mouse L cells with the 10.3-5'rPRL gene sequence of BrdU-responsive cells, both the human growth hormone and the HSV1TK genes are amplified in response to 5-bromodeoxyuridine. This observation is substantiated by BrdU-induced amplification of the cotransferred bacterial Neo gene. Cotransfection studies reveal that the BrdU-induced amplification capability is associated with a 4-kb DNA sequence in the 5'-flanking region of the rPRL gene of BrdU-responsive cells. These results demonstrate that genes of heterologous origin, linked or unlinked, and selected or unselected, can be coamplified when located within the amplification boundary of the Amplicon sequence.

Animals↗
PubMed1987

In vivo comparison of phenylephrine and phenylephrine oxazolidine instilled in the monkey eye.

The ocular and cardiovascular effects as well as aqueous humor and plasma concentrations of 10% phenylephrine HCl and 1% phenylephrine oxazolidine (prodrug) were compared in cynomolgus monkeys. A volume of 25 microliters of either drug was administered to one eye followed by blood pressure, pulse, and pupillary measurements at 10 min intervals up to 60 minutes. Careful slit lamp examinations of the anterior segment, indirect ophthalmoscopy of the vitreous and retina, and ERGs were performed at 60 minutes. Four plasma determinations of phenylephrine following administration of either drug were made between 5 and 60 minutes. Measurement of phenylephrine in aqueous humor was also determined at 60 minutes following all other measurements. The maximal pupillary dilation after administration of 1% prodrug (mean + s.d. = 4.4 + 0.5 mm, n = 12) was slightly greater than after administration of phenylephrine 10% (mean + s.d. = 3.9 + 0.8 mm, n = 12). The differences in pupillary diameter from 20 through 40 minutes were statistically greater for the prodrug. The greater pupillary diameter at the earlier times resulted in an onset of pupillary dilation approximately 15 minutes earlier for the 1% prodrug. There was no ocular toxicity from either drug. Neither drug resulted in any ERG changes compared to baseline. Significantly higher aqueous humor levels along with lower plasma levels were detected and found to be statistically different following administration of the 1% prodrug when compared to 10% phenylephrine.

Animals↗
PubMed1987

Comparison of commercial kits for the detection of anti-nDNA antibodies using Crithidia luciliae.

The reactions of sera from 15 selected patients with connective tissue diseases and 4 selected control people were compared with the use of five commercial kits detecting anti-nDNA antibodies by indirect immunofluorescence on Crithidia luciliae. The cases with systemic lupus erythematosus (SLE) and a related condition reacted with the kinetoplasts of the C. luciliae in each kit tested with one exception, notably a case of drug-induced LE. The four control cases selected for a trace of staining of the nuclei of C. luciliae gave negative reactions with the kinetoplasts. The titer for each individual positive serum varied from 1.36 to 2.67 (mean SG 2.04) geometric standard deviation units. The staining pattern of sera positive for anti-nDNA antibodies on C. luciliae included reactivity of the kinetoplast with or without nuclear staining. The drug-induced LE serum produced only nuclear staining with no significant kinetoplast staining, i.e., a negative test for anti-nDNA antibodies. Patient control sera stained only the nucleus when any reactivity on C. luciliae was present. Generally, there were no major differences in titers and patterns of sera when comparisons were made between manufacturers. The sera were also tested by the Farr radioimmunoassay and the latex nucleoprotein test. The results of both of these assays correlated in most cases with the C. luciliae reactions.

Antibodies, Antinuclear↗
PubMed1987

Critical level of oxygen delivery after cardiopulmonary bypass.

The relationship between oxygen uptake (Vo2) and delivery (Do2) was examined in 64 patients immediately after cardiopulmonary bypass. In 44 patients with lactate levels below 2.5 mmol/L, Vo2 decreased proportionally when Do2 decreased below 300 ml/min X m2. At a Do2 over this level, Vo2 plateaued at 105 +/- 13 (SD) ml/min X m2. In a contrasting group of 22 patients with blood lactate levels above 2.5 mmol/L, Vo2 changes depended on changes in Do2 both alone and below 300 ml/min X m2.

Cardiopulmonary Bypass↗
PubMed1987

Substrate specificity of anti-epithelial antibodies of pemphigus vulgaris and pemphigus foliaceus sera in immunofluorescence tests on monkey and guinea pig esophagus sections.

The indirect immunofluorescent (IF) reactivity of the pemphigus antibodies in sera of 21 cases of pemphigus vulgaris (PV), 15 cases of pemphigus foliaceus (PF), and 14 cases of Brazilian PF (BPF) was compared on 2 substrates, notably monkey esophagus (ME) sections and guinea pig esophagus (GPE) sections. The IF reactions of the pemphigus antibodies of PV could be distinguished from those of PF or BPF by differences in their reactivity on ME and GPE sections in 98% of the cases examined in this study. In most cases, the pemphigus antibodies of PV cases gave higher titers and stronger IF staining reactions on ME sections, while those of PF and BPF cases gave stronger reactions on GPE sections. In addition, most (13 of 21) PV sera react with the lowest 3-4 cell layers of ME sections, while most (13 of 15) PF sera failed to do so but did react with the upper layers of the sections. Importantly, in 8 of the 50 cases examined by IF, the choice of substrate affected the detectability of the pemphigus antibodies, i.e., 4 of 15 PF and 2 of 14 BPF sera reacted only with GPE and 2 of 21 PV sera reacted only on ME. These research findings point to the need for an evaluation of the combined use of ME and GPE in routine diagnostic studies of pemphigus antibodies.

Animals↗
PubMed1987

IgA anti-endomysial antibodies in dermatitis herpetiformis: correlation with jejunal morphology, gluten-free diet and anti-gliadin antibodies.

Circulating IgA-class anti-endomysium antibodies (EmA) can be detected by indirect immunofluorescence on monkey oesophagus sections. We found EmA in 22 (76%) of 29 patients with dermatitis herpetiformis (DH) on a normal, gluten-containing diet. The highest frequency (100%) of EmA was observed in patients with sub-total villous atrophy. IgA-class antigliadin antibodies (AGA) were found using an ELISA method in 59% of 29 DH patients and in 86% of those with sub-total villous atrophy. There was a significant correlation between EmA titres and AGA levels in individual patients. Gluten-free diet (GFD) treatment caused a rapid decrease in EmA titres; only three of the 12 patients still showed raised EmA after 6-12 months on a GFD and two of these three had failed to adhere to a strict diet. In contrast, no decrease in EmA titres occurred in four patients maintained on a normal diet, and two of the three patients with initially negative EmA developed positive titres when continuing on a normal diet. These results show that both IgA-class EmA and AGA are good indicators of jejunal damage in DH. The rapid fall of EmA titres after gluten withdrawal indicates that this test is also useful for monitoring a patient's adherence to a GFD.

Adolescent↗
PubMed1987

Pain after laparoscopy related to posture and ring versus clip sterilization.

In an attempt to reduce pain after laparoscopy, presumed to be due to persistence of CO2 in the peritoneal cavity especially under the diaphragm, women were kept 30 degrees head down for 30 min immediately after operation. By random selection 67 treated patients were compared with 64 kept flat, postoperative symptoms being recorded at fixed times for 3 days. Although tilting was found to be of no significant benefit there were two useful findings. In both groups there was a significant fall in the frequency of upper abdominal pain during the first postoperative night from about 53% to about 25%, followed by a rise after returning home on the first postoperative day to about 60% and only a slow fall in the next 2 days. The severity of pain followed the same pattern. Patients should be warned to expect increased pain on ambulation after leaving hospital. Also, there was doubling in lower abdominal pain during the first 6 h associated with the use of Falope rings for sterilization, compared with either Hulka clip sterilization or only diagnostic laparoscopy.

Female↗
PubMed1987

Plasma levels and effects of nortriptyline in geriatric depressed patients.

Pharmacokinetic, therapeutic effects, and side effects of nortriptyline were studied in geriatric depressed patients treated with a standard dose of 150 mg/day. Plasma levels and elimination half-life of nortriptyline were no different in geriatric patients than younger patients. The antidepressant therapeutic effects of nortriptyline appeared to be similar in geriatric patients as in younger depressed patients. Geriatric patients experienced few subjective side effects of nortriptyline. Overall, the drug produced no clinically significant changes in several parameters of the EKG, and no geriatric patient experienced tachycardia on nortriptyline. Nortriptyline did induce significant orthostatic hypotension in the systolic component, but not in the diastolic component. However, the orthostatic hypotension produced by nortriptyline was not greater in geriatric patients than in younger patients treated with the same dose.

Age Factors↗