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Biomedical subjects

J Black

Publications and source records attributed to J Black.

At least 199 records · Page 11Linked to original sources
PubMed1991

Metabolism of [1-13C]glucose in a synaptosomally enriched fraction of rat cerebrum studied by 1H/13C magnetic resonance spectroscopy.

This study explored the utility of 1H and 13C magnetic resonance spectroscopy to study a standard synaptosomally enriched fraction (P2 pellet) made from rat cerebrum. The preparations contained high concentrations of N-acetylaspartate and gamma-aminobutyric acid and low concentrations of glutamine, indicating that they were in fact rich in neuronal cytosol. The metabolic competence of the preparation was assessed by quantitative measurements of its ability to convert [1-13C]glucose into lactate, glutamate, aspartate, and other metabolites under well oxygenated conditions in 30 minutes. The minimum mean glycolytic rate was 0.8 mM glucose/min and the flow through the tricarboxylic acid cycle was equivalent to 0.2 mM glucose/min.

Animals↗
PubMed1991

Ten years' experience with continuous ambulatory peritoneal dialysis.

Up to January 1989, 171 patients were trained at our center on continuous ambulatory peritoneal dialysis (CAPD), and 17 on continuous cyclic peritoneal dialysis (CCPD). Over 10 years, we have gained 5,068 patient-months experience. Patient survival was 60% and 31% at 5 and 10 years, respectively. In contrast, diabetics had a survival of 32% at 5 years. Major complications included 499 new episodes of peritonitis, 304 exit-site infections, 22 hernias, five bowel perforations, one hydrothorax, and three episodes of sclerosing encapsulating peritonitis. Our technique survival has been 62% and 40% at 5 and 10 years, respectively. We believe that CAPD is a viable dialysis technique for long-term treatment of chronic renal failure and it should be offered as an option to intermittent hemodialysis.

Adolescent↗
PubMed1991

Bovine immunodeficiency virus: immunochemical characterization and serological survey.

Bovine immunodeficiency virus (BIV) was purified by isodensity centrifugation; viral activities were monitored in gradient fractions using the reverse transcriptase assay and a p26-specific monoclonal antibody ELISA. In the coincident peak fractions (density about 1.17 g/ml) proteins with Mr values of 26K, 17K, 53K, 14K and 100K (with decreasing intensity) were detected by Western blotting using serum of a calf after experimental BIV infection. When 957 randomly collected cattle sera from The Netherlands were tested by indirect immunofluorescence and confirmed using Western blot and/or radioimmunoprecipitation, 1.4% appeared seropositive. Thus BIV infection is not uncommon in one European cattle population.

Animals↗
PubMed1991

Characterization of exopolymers of aquatic bacteria by pyrolysis-mass spectrometry.

Exopolymers from a diverse collection of marine and freshwater bacteria were characterized by pyrolysis-mass spectrometry (Py-MS). Py-MS provides spectra of pyrolysis fragments that are characteristic of the original material. Analysis of the spectra by multivariate statistical techniques (principal component and canonical variate analysis) separated these exopolymers into distinct groups. Py-MS clearly distinguished characteristic fragments, which may be derived from components responsible for functional differences between polymers. The importance of these distinctions and the relevance of pyrolysis information to exopolysaccharide function in aquatic bacteria is discussed.

Carbohydrates↗
PubMed1991

Left ventricular hypertrophy associated with chronic cocaine abuse.

BACKGROUND: This study was performed to determine whether chronic cocaine abuse is associated with left ventricular hypertrophy in humans. METHODS AND RESULTS: A consecutive series of 40 chronic cocaine abusers 23-44 years old who were enrolled in an inpatient drug rehabilitation program were considered for the study. Subjects with elevated resting blood pressure (n = 4) or a history of hypertension (n = 3) were excluded. Technically adequate two-dimensional echocardiograms were obtained in 30 cocaine abusers and 30 age- and race-matched normal control subjects. All subjects were men, and the groups were similar with regard to resting blood pressure, height, weight, and body surface area. All echocardiograms were read in blinded fashion, and left ventricular mass was calculated by the area-length method. Left ventricular cavity dimensions and wall motion were normal in all subjects. Left ventricular mass index was higher in the cocaine group (103 +/- 24 versus 77 +/- 14 g/m2, p = 0.0001). Posterior wall thickness was increased (1.2 cm or more) in 13 cocaine abusers (43%) compared with four controls (p = 0.0099). CONCLUSIONS: Chronic cocaine abuse is associated with increased left ventricular mass index and wall thickness. Left ventricular hypertrophy may provide a substrate facilitating the development of myocardial ischemia and/or arrhythmias in cocaine abusers.

Adult↗
PubMed1991

Diagnosis of sleep-disordered breathing by half-night polysomnography.

We hypothesized that sleep-disordered breathing (SDB), defined by the apnea index (AI), the apnea + hypopnea index (A + H/I), or the desaturation event frequency (number of desaturations greater than 5%/h slept) (DEF), could be diagnosed after less than full-night polysomnography (PSG). Forty-eight consecutive full-night PSG sessions were evaluated by separately analyzing the first half (PSG-1/2) and the total (PSG-T) sleep time: 134.42 +/- 35.7 and 277.15 +/- 56.5 min (mean +/- SD), respectively. PSG-1/2 and PSG-T were not different with respect to AI. The DEF was statistically but not clinically higher during PSG-1/2 (41.72 +/- 41 versus 37.95 +/- 35.8, p = 0.04). Sensitivities, specificities, and predictive values of each PSG-1/2 parameter were determined by comparing the values with those measured during PSG-T, using cutoff frequencies of both 5 and 10 events/h slept to define SDB. At a cutoff frequency of 10, sensitivities and positive predictive values were high for all PSG-1/2 parameters (range, 94.6 to 96.9%). The specificities of the DEF and AI during PSG-1/2 were also high (93.75 and 95%, respectively), but the negative predictive value of the DEF was substantially better (93.75 versus 83.3%). With SDB defined by 5 events/h slept, there also were high sensitivities (87.9 to 93%), positive predictive values (93.6 to 100%), and specificities (86.7 to 100%) for all parameters. Negative predictive values, however, were substantially reduced (62.5 to 76.5%). We conclude that PSG during 2 h of sleep is an appropriate method for evaluating SDB.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation Studies as Topic↗
PubMed1991

Visitors' perceptions of continuing care.

One hundred and sixty-one replies (72% response rate) to a questionnaire sent to regular visitors of elderly continuing care patients showed that 73% of the visitors were first degree relatives. Sixty three per cent visited more than once per week, and were more likely to do so when the distance travelled was less than five miles (p less than 0.01) and the cost under pounds 2.00 (p less than 0.01). The physical surroundings and nursing care were rated as adequate or better by 80% and 92% respectively. Numbers of nurses were rated as inadequate by 44% and numbers of physiotherapists as inadequate by 46%. Increasing the numbers of nurses was suggested as the measure that would most improve the patients' quality of life. To facilitate visiting, continuing care units should be sited close to the community they serve.

Attitude to Health↗
PubMed1991

Release and excretion of metal in patients who have a total hip-replacement component made of titanium-base alloy.

Serum concentration and urinary excretion of titanium, aluminum, and vanadium were measured for patients who had a well functioning cementless primary total hip replacement of one of two different designs, for patients who had a loose total hip replacement that was to be revised, and for control subjects who had no implant. Serum concentrations of titanium were elevated approximately twofold in the patients who had a loose implant, compared with the values for the control subjects. No major differences in terms of urine concentration of titanium, serum concentration of aluminum, or urine concentration of aluminum were observed among any of the groups that were studied. Concentrations of vanadium were uniformly low in all groups.

Adult↗