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Biomedical subjects

K Collins

Publications and source records attributed to K Collins.

108 records · Page 6Linked to original sources
PubMed1983

Fatal infection in mice after injection of immunosuppressive serum fractions from surgical patients.

Following surgical or accidental trauma many patients show suppression of cellular immunity. In this investigation sera from severely burned patients and patients undergoing aortic aneurysm repair were studied. Sera shown to suppress phytohaemagglutinin-induced blastogenesis of normal human lymphocytes were fractionated using ion exchange and G25 Sephadex chromatography. Suppressive activity was largely confined to a low molecular weight (LMW) fraction and was dose dependent. LMW fractions of normal sera had no significant suppressive activity. The purpose of this study was to test the causal relationship between immunosuppressive serum and decreased resistance to bacterial infection. Listeria monocytogenes infected mice were used as an in vivo model to test suppression of cellular immunity. Injection of LMW fractions of suppressive sera significantly increased mortality in these mice, but had no effect on non-infected mice. There was good correlation between the in vitro and in vivo effects of the suppressive fractions. These results suggest that a circulating factor in the serum of injured patients suppresses cellular immunity and may be responsible for impaired resistance to infection.

Adult↗
PubMed1980

Evidence for a steroid receptor in rheumatoid synovial tissue cells.

One mechanism by which glucocorticoids could exert their anti-inflammatory action is via rapidly saturable, stereo-specific cytoplasmic protein receptors. This report is of an investigation into such a possibility in synovial cells. Synovium, obtained from knee joints of rheumatoid patients undergoing surgery, was incubated with clostridiopeptidase A and trypsin-EDTA to obtain cell suspensions. These, together with cells obtained from synovial fluid aspirated from patients with rheumatoid arthritis, were identified by electron microscopy. Duplicate samples of these cell suspensions were incubated with increasing concentrations of H3Dexamethasone (1 x 10(-10)M-1 x 10(-9)M) for 30 minutes at 37 degrees C. Analysis of the proportion of steroid bound to whole cells showed evidence for specific, rapidly saturable, receptors in the cells obtained from synovial tissue, but this was not found in synovial fluid cells. Electron micrographs showed that cells obtained from synovial tissue consisted of synovial fibroblast - and macrophage-types, lymphocytes, monocytes and macrophages. Polymorphonuclear leucocytes appeared to be absent. However, in synovial fluid cell type polymorphonuclear leucocytes were the predominant cell type. We concluded from this, that one or more of the cell types present in synovial tissue contain a specific steroid receptor, but that this is lacking in synovial fluid polymorphonuclear leucocytes.

Arthritis, Rheumatoid↗
PubMed1977

Toxicity of prostaglandins A1 and A2 for cells in culture.

Prostaglandins A1 and A2, in concentrations near 3 x 10(-5) M, produced striking toxicity to muscle, skin and liver cells in culture. Prostaglandins E and F2alpha were much less active in this regard. Toxicity could be measured by reduction in viable cell number, protein and DNA synthesis in the cultures. The sensitivity of cultured cells was related to their age and population density. Dense cultures were sensitive early, in the first 2 days, and resistant after they manifested confluent growth. Sparse cultures remained sensitive later while they continued DNA synthesis and active cell division. It is hypothesized that the prostaglandin A effect is related to active cell division and DNA synthesis.

Cell Division↗
PubMedDate not supplied

Provider characteristics: impact on bone density utilization at a health maintenance organization.

OBJECTIVE: Information from bone mineral density (BMD) is relevant in guiding postmenopausal osteoporosis prevention and treatment, yet many providers do not typically order BMDs. This study was designed to identify physician characteristics associated with utilization of bone densitometry in a northeastern US health maintenance organization (HMO). DESIGN: Internal medicine primary providers in practice at a northeastern HMO between April 1997 and March 1998 were categorized by BMD utilization, based on the number of BMDs performed during that time per number of women older than 50 years in their patient panel. In one analysis, providers in the highest quintile for this parameter were considered "high utilizers" (n = 25), and those in the lowest quintile, "low utilizers." These groups were compared with respect to provider characteristics and practice composition. In a second analysis, multiple variable linear regression was used to predict the likelihood of utilization of BMD as a function of those parameters for all providers. RESULTS: The range of BMDs by provider was 0 to 190 per 1,000 women >50 years (median = 34) over this 1-year period. Providers who were high utilizers had a significantly greater number of female patients more than age 50 in their practice (p < 0.05) and were also more likely themselves to be female (62% vs. 48%; p < 0.05). There was no association between BMD utilization and age of provider or years in practice. Female provider gender (p < 0.01) and greater percentage of women more than age 50 in the practice (p < 0.05) were independent predictors of BMD utilization in a multivariate model. CONCLUSION: BMDs were infrequently utilized by the majority of providers over this 1-year period. Female provider gender was associated with a significantly greater likelihood of BMD utilization that was not simply explained by the greater number of women in these providers' practices. These findings may be relevant to identifying strategies to improve bone health care in this population.

Absorptiometry, Photon↗
PubMedDate not supplied

Magnetic resonance imaging and ultrasonography in the diagnosis of a malignant peripheral nerve sheath tumor in a dog.

A 9-year-old male neutered mixed breed dog had a two-month history of progressive left thoracic limb lameness. There was electromyographic evidence of denervation potentials in all muscles of this limb. In magnetic resonance images a multilobulated, hyperintense mass was visible caudal to the middiaphysis of the left humerus on T-2 weighted images. The mass, which was isointense with surrounding tissue on T1 weighted images, extended proximally towards the brachial plexus. The mass was also visible as a fusiform structure of mixed echogenicity sonographically, although fine-needle aspiration performed at this time was nondiagnostic. A malignant peripheral nerve sheath tumor was diagnosed histopathologically.

Action Potentials↗
PubMedDate not supplied

Overuse injuries in triathletes. A study of the 1986 Seafair Triathlon.

A questionnaire was mailed to 600 to 657 finishers in the Seafair Triathlon (July 20, 1986); 45% of those polled returned the questionnaire. Over the preceding year, 49% of the respondents suffered a training-related injury serious enough to cause them to stop training for at least 1 day, seek medical care, or take medicine, Seventy percent of the injuries were due solely or partly to running. The knee, shoulder, and ankle were most frequently affected. Female triathletes and those more than 40 years of age showed a similar injury incidence and distribution. Elite triathletes averaged more miles per week in each sport than the athletes as a whole and showed a higher incidence of injury (60%), although this was not a significant difference. Higher weekly swimming, cycling, and running mileages did not lead to a higher incidence of injury. The likelihood of injury was independent of age, sex, body mass index, mileage per week, or other training factors evaluated in the study.

Adult↗
PubMedDate not supplied

Developing patient satisfaction questionnaires.

Karen Collins provides a practical guide to undertaking a patient satisfaction survey. She outlines the background to patient satisfaction research and highlights some of the main issues surrounding patient satisfaction measures.

Humans↗
PubMedDate not supplied

Combined treatment with serine protease inhibitor aprotinin and matrix metalloproteinase inhibitor Batimastat (BB-94) does not prevent invasion of human esophageal and ovarian carcinoma cells in vivo.

Many studies have highlighted the role played by matrix metalloproteinases MMP-2 and -9, by serine proteases uPA and plasmin in tumor cell invasion. This study investigates the impact of the MMP-inhibitor Batimastat and/or the serine protease inhibitor Aprotinin on the in vitro proteolytic activity and in vivo invasive behavior the of esophageal (OC1) and ovarian (OVCAR-3) carcinoma cells. In presence and absence of inhibitors, proteolytic activity of the tumor cells was determined by caseinolytic and collagenolytic in vitro assays and tumor cell invasion by intraperitoneal inoculation of the tumor cells into nude mice. In vitro, Aprotinin, tested alone or in combination with Batimastat, efficiently inhibited degradation of collagen IV and casein by the tumor cells. Batimastat alone had no effect on caseinolytic activities and only partially blocked collagen-type-IV-degradation by the tumor cells. In vivo, Aprotinin tested alone or in combination with Batimastat did not prevent tumor cell invasion. Treatment of tumor bearing mice with Batimastat significantly inhibited tumor growth but promoted tumor cell invasion into the liver. Our findings demonstrate that the inhibition pattern of cellular proteolytic activity achieved in vitro by a serine protease and an MMP inhibitor may lead to predictions that are not necessarily verified in vivo and may even have adverse effects.

Adenocarcinoma↗