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Biomedical subjects

D S Kittur

Publications and source records attributed to D S Kittur.

26 records · Page 2Linked to original sources
PubMed1990

Allele specific oligonucleotide probes for mouse I-A region and gene: I-A beta.

MHC Class II gene expression is being intensively studied in vitro. In vivo class II gene expression that occurs during G.V.H.R. and allograft reaction has not been studied as well as the gene expression in vitro because such studies require unambiguous detection of graft or host specific MHC class II genes. Although this is possible by using allele specific oligonucleotide probes for individual class II genes, such probes for class II genes in mice have not been described before. We compared the nucleotide sequences of I-A beta genes from various haplotypes and selected a region of minimal homology in the 2nd exon of this gene. We synthesized two oligonucleotide probes corresponding to a 20 nucleotide stretch in the hypervariable region of the I-A beta 1 genes of H-2k and H-2d haplotype mice. These probes specifically detect I-A beta mRNA from mice of appropriate haplotypes. These allele-specific probes should help study the in vivo expression of graft or host specific I-A genes in G.V.H.R. or allograft reaction.

Animals↗
PubMed1990

Impact of an organ donor and tissue donor advocacy program on community hospitals.

A crucial shortage of organ donors exists in the United States. The majority of donor referrals come from large (greater than 500) beds) hospitals and trauma centers. To determine whether a significant number of donors who are not being recognized or referred also existed in medium-sized (300 beds) community hospitals, a Donor Advocacy Program was instituted at Francis Scott Key Medical Center in May 1987. This team developed policies and procedures to identify potential donors and conducted educational programs for physicians and nurses. A designated "Donor Advocate" made daily rounds on the inpatient units to maintain donor awareness and facilitate potential donations. After the first year, the program was evaluated. In comparison to the average of the previous three years, donor referrals increased by approximately 400 per cent and tissue donations increased over 500 per cent. Four organs were retrieved from two donors. It is concluded that an increase in referrals and tissue donations can be achieved at community hospitals through a structured donor awareness program. Recommendations are made to further examine the age group most often eligible for organ and tissue donations in community hospitals and target educational efforts accordingly. Commitment of hospital administration is vital to a positive outcome in such a program.

Baltimore↗
PubMed1989

Eversion of difficult ileostomies by guy rope suture technique.

In the creation of a permanent ileostomy, a fully everted nipple ensures a good fit of the stomal appliance. In normal bowel segment this may not pose a problem, but forceful attempts at eversion in diseased, thickened, and friable bowel may result in damage to the bowel segment. In order to prevent this, we developed a technique that uses the guy rope principle to evert the necessary length of bowel. The technique described in this article may also be used to evert healthy segments of bowel during creation of a permanent ileostomy.

Humans↗
PubMed1988

Restricted expression of mitogen-induced high affinity IL-2 receptors in aging mice.

Several lines of indirect evidence suggest that the number and/or affinity of IL-2R expressed by activated T lymphocytes declines with age and that this decline is implicated in the age-related proliferative impairment of Ag or mitogen-stimulated T cells. In an attempt to provide a direct demonstration of such a defect, various experimental approaches were used to analyze the expression of high and low affinity IL-2R as well as their functional properties in relation to age in purified populations of murine T lymphocytes. IL-2R were induced by Con A-activation which involves a transmembrane signaling mechanism or by exposure to phorbol dibutyrate (PDBu) which bypasses such a pathway. Consistent with the previously reported age-related defect in signal transduction, a major deficiency in the expression of high affinity IL-2R was observed in mitogen-activated cells derived from aged animals. As expected, PDBu-induction circumvented the transmembrane signaling defect and resulted in the restoration of a measurable amount of high affinity IL-2R expressed by cells from aged mice early after activation. The functional properties of the IL-2R expressed as a consequence of Con A or PDBu induction were investigated by assessing the proliferative response induced through the high affinity IL-2R as compared to that mediated by the beta-chain alone. Although Con A-induction resulted in a decreased expression of high affinity IL-2R by T lymphocytes derived from aged mice, the ability of these receptors as well as that of their beta-chain component to transmit a proliferative signal was identical in both age groups. In contrast, PDBu induced in both cell populations the expression of functionally aberrant IL-2R, unable to signal for proliferation unless excessively high concentrations of rIL-2 were available. The quantitative minimal estimate of the frequency of Con A-activated, IL-2-responsive cells showed a fourfold age-associated decrease, confirming the inability of a subpopulation of T lymphocytes from aged mice to express a sufficient density of high affinity IL-2R as a consequence of mitogenic activation.

Aging↗
PubMed1988

Modulation of HLA antigens in response to the binding of epidermal growth factor by A431 cells.

In a previous study [(1984) J. Cell Biol. 98, 725-731] we showed that the level of human MHC, HLA antigens on A431 carcinoma cells is reduced after these cells bind epidermal growth factor (EGF). Here we use flow cytometry to determine the effects of various doses and times of EGF treatment on HLA expression. We then show that the reduction in HLA expression is associated with a reduction in the level of phosphorylation of immunoprecipitable surface HLA antigens, although longer exposure of cells with EGF increased both surface HLA expression and their phosphorylation levels. Lateral diffusion of HLA antigens is lower in EGF-treated than in control cells. The lower diffusion coefficients measured may be causally related to the decreased phosphorylation of HLA antigens.

Aged↗
PubMed1981

Treatment of severe burns with widely meshed skin autograft and meshed skin allograft overlay.

A major factor limiting survival following extensive thermal injury is insufficient availability of donor sites to provide enough skin for the required grafting procedures. While 3:1 expanded mesh autograft have aided greatly in better utilization of available sites, a 6:1 or greater expanded mesh graft is often accompanied by significant loss of the graft. A technique has been developed in which widely meshed autograft (6:1 or greater) is covered by a 1.5 or 3:1 expanded mesh allograft to provide better take. Fourteen patients have been treated using this technique covering areas of 1 to 15% body surface area, and the results compared with the take and ultimate coverage of 3:1 expanded mesh autografts. The size of burn of these patients varied between 25% total/11% 3 degrees and 98% total/95% 3 degrees (average 58%/47%). Eleven procedures were done after excision to fascia, four after tangential excision, and the remaining seven grafts were placed on granulating wounds. The allograft used for overlay had been preserved by freezing and storage in liquid nitrogen. Epithelial outgrowth from the autograft was more rapid than from the allograft, but both types of graft took and became vascularized initially. There was an average of 99% autograft take and 95% allograft take. However, three patients subsequently had graft loss as a result of burn wound sepsis. The allografts gradually rejected 3 to 30 days post-grafting with the time of 50% loss averaging 14 days. Rejection of the allograft was not associated with acute inflammation or loss of autograft. The ultimate cosmetic appearance and function was acceptable in all. This new technique appears to offer significant advantages for the grafting of extensively burned patients with limited donor sites.

Adolescent↗