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Biomedical subjects

K Wilson

Publications and source records attributed to K Wilson.

At least 253 records · Page 14Linked to original sources
PubMed1990

Time-resolved X-ray crystallographic study of the conformational change in Ha-Ras p21 protein on GTP hydrolysis.

Crystals of Ha-Ras p21 with caged GTP at the active site have been used to investigate the conformational changes of p21 on GTP hydrolysis. The structure of the short-lived p21.GTP complex was determined by Laue diffraction methods. After GTP hydrolysis, substantial structural changes occur in the parts of the molecule implicated in the interaction with GTPase-activating protein. The trigger for this process seems to be a change in coordination of the active-site Mg2+ ion as a result of loss of the gamma-phosphate of GTP.

Binding Sites↗
PubMed1990

Extensor tendon repair: an animal model which allows immediate post-operative mobilisation.

In adult rabbits, an experimentally transected digital extensor tendon was repaired. The technique employed a tongue, created from the proximal tendon, folded over to bridge the transection and reattached distally. Animals were allowed immediate post-operative mobilisation. Tendon material, 14-120 days post-operatively, was examined ultrastructurally in control and experimental animals from four different zones within the repaired tendon. The operation was well tolerated and adhesion free. Associated with the repair, two types of collagen fibril populations were observed. Firstly, in areas where tendon tissue had been removed, there was a population of fibrils with a narrow range of diameters. Secondly, in areas where tendon tissue was subjected to an increased level of stress per unit cross-sectional area, a population of fibrils with a range of diameters similar to that of controls but with a marked increase in the percentage of small diameter fibrils. The relevance of these observations to human tendon repair is discussed.

Animals↗
PubMed1990

Immunopathogenesis and immunotherapy of type 1 diabetes.

Research in recent years has elucidated more clearly the genetic and immunopathogenic basis as well as the natural history of Type 1 diabetes mellitus. The development of Type 1 diabetes can be conceptually divided into stages, beginning in part with a human leukocyte antigen (HLA)-restricted genetic susceptibility. In some genetically susceptible subjects, a triggering event activates both cellular and humoral autoimmunity. Glucose-stimulated insulin secretion and beta cell mass diminish as anti-islet autoimmunity progresses. This process culminates in overt diabetes when only residual beta cell mass (estimated to be less than 10%) remains. Complete beta cell destruction follows within months to years of diagnosis. Most attempts at interrupting beta cell destruction have taken the form of broad immunosuppressive therapy begun at diagnosis when beta cell destruction is nearly complete. Greater understanding of early immune mediators and refinement of techniques to identify subjects at risk for Type 1 diabetes have set the stage for more specific immunomodulation targeted earlier in the course of the disease. We will review these recent advances in understanding the immunopathogenesis of Type 1 diabetes as they pertain to current and future trials of immunotherapy.

Animals↗
PubMed1990

Retrospective cohort study of duodenal ulcer disease in U.S. Air Force pilots.

Current waiver policy for duodenal ulcer (DU) disease in pilots is based on data from civilian populations since little information is available on the course and prognosis of this disease in pilots. The United States Air Force (USAF) waiver file and the Office of Medical Support database were used to identify 100 pilots with onset of DU between 1981 and 1987. A written questionnaire was returned by 86 (86%) of these pilots. The incidence of DU in USAF active-duty pilots was estimated to be 5.0 per 10,000 pilot-years. DU was significantly associated with cigarette smoking. Bleeding ulcers were significantly associated with aspirin use. After 587 person-years of follow-up there were no fatalities; serious sequelae were reported in only 6 pilots, and moderate sequelae in only 12 others. The risk of recurrence of DU in this population was not appreciably higher among those initially presenting with hemorrhage.

Adult↗
PubMed1989

Coupling capillary zone electrophoresis and continuous-flow fast atom bombardment mass spectrometry for the analysis of peptide mixtures.

Combined capillary zone electrophoresis (CZE)-continuous-flow fast atom bombardment (CF-FAB) mass spectrometry is described for the analysis of mixtures of peptides. A 90 cm x 50 microns I.D. fused-silica capillary column was used for electrophoretic separations and was connected to the CF-FAB probe via an interface which allows a total flow into the mass spectrometer of about 5 microliters/min. Solutions of peptides were pneumatically loaded onto the CZE capillary, providing sample amounts of 0.1-20 pmol. The magnetic mass spectrometer was scanned over the desired mass range, usually between m/z 500 and 2500. Results are shown for separation and analysis of mixtures of synthetic peptides and also for protease digests of recombinant human growth hormone and horse heart cytochrome c.

Electrophoresis↗
PubMed1989

Preliminary X-ray crystallographic study of malate dehydrogenases from the thermoacidophilic Archaebacteria Thermoplasma acidophilum and Sulfolobus acidocaldarius.

Malate dehydrogenases from the thermoacidophilic Archaebacteria Thermoplasma acidophilum and Sulfolobus acidocaldarius have been crystallized and characterized by X-ray diffraction measurements. Crystals of the enzyme from T. acidophilum display space-group symmetry P2(1), a = 63 A, b = 135 A, c = 83 A and beta = 105 degrees; they scattered to approximately 4 A resolution. Two crystal modifications of malate dehydrogenase from S. acidocaldarius were characterized; one displayed trigonal symmetry corresponding to space groups P321, P3(1)21 or P3(2)21 with lattice parameters a = 151 A and c = 248 A and with resolution approximately to 5 A, whereas the other modification displayed space group symmetry I23 or I2(1)3 with lattice parameters a = 129 A and approximately 4.5 A resolution.

Archaea↗
PubMed1989

[Thorotrast].

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Contrast Media↗
PubMed1989

[AIDS epidemiology].

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Acquired Immunodeficiency Syndrome↗
PubMed1989

[AIDS epidemiology].

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Acquired Immunodeficiency Syndrome↗
PubMed1989

Irritable bowel syndrome in the gynecological clinic. Survey of 798 new referrals.

A study of the prevalence of symptoms suggestive of irritable bowel syndrome in 798 women referred to a gynecological clinic is reported; 321 women referred to dermatology and ear, nose, and throat clinics served as controls. Data were collected by a mailed symptom questionnaire. The prevalence of irritable bowel syndrome in the gynecological group was 37.3% compared with 27.7% in controls (P = 0.003). Approximately 50% of women referred with abdominal pain, dyspareunia, and dysmenorrhea had symptoms compatible with irritable bowel syndrome (P less than 0.005), whereas the prevalence in those referred for cervical abnormalities, termination/sterilization or perineal problems was similar to that of controls (28%). Patients referred with urinary symptoms, heavy periods, nonmenstrual bleeding, vaginal discharge, and infertility had an intermediate prevalence of irritable bowel syndrome (35-45%). This study suggests that either many women with irritable bowel syndrome are being wrongly referred to gynecologists or raises the possibility that symptoms currently regarded as indicative of irritable bowel syndrome may be associated with certain gynecological disorders.

Abdominal Pain↗