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Biomedical subjects

D Martin

Publications and source records attributed to D Martin.

At least 595 records · Page 33Linked to original sources
PubMed1991

Colonic volvulus. The Army Medical Center experience 1983-1987.

Colonic volvulus was first described in 1836 by von Rokitansky. The condition has been a formidable one, fraught with innumerable complications responsible for many deaths. Even with advances in surgical technology, mortalities have remained high. Often the diagnosis is delayed for hours or even days after presentation, and serious concomitant systemic diseases are often present. Treatment has been controversial, particularly the role of elective resection following successful nonoperative reduction. The Army Medical Center experience with colonic volvulus from 1983 through 1987 is reviewed. Fifty-four patients at the eight medical centers carried this diagnosis. Their presenting signs and symptoms are discussed. The Army patients are compared and contrasted with reviews presented in the surgical literature, and conclusions are made to give guidelines for diagnosis and treatment.

Adolescent↗
PubMed1990

Combined lipase deficiency in the mouse. Evidence of impaired lipase processing and secretion.

Newborn combined lipase-deficient (cld) mice have severe hypertriglyceridemia associated with a marked decrease of lipoprotein lipase (LPL) and hepatic lipase (HL) activities. Since the cld mutation and lipase genes reside on separate chromosomes, combined lipase deficiency cannot result from defects occurring within the LPL or HL structural genes. To elucidate the biochemical basis of this trans-acting defect, cld mice were compared to unaffected littermates for changes in lipase mRNA levels, rates of synthesis, and posttranslational processing and secretion. LPL and HL mRNA levels in cld liver and LPL in cld heart were comparable to controls; corresponding lipase synthetic rates were modestly decreased by about 30%. However, these reduced synthetic rates were not lipase-specific, since the rates of apolipoprotein (apo) A-I and apoA-II synthesis in cld liver were similarly decreased. Despite LPL synthetic rates that were 70% of controls, LPL mass in cld postheparin plasma was markedly reduced to only 7% of control values, suggesting that the majority of LPL is not secreted but remains intracellular. Consistent with a lipase secretory defect, neither the LPL nor HL oligomannosyl forms were converted to their respective complex forms in cld tissues, indicating that the lipases had failed to move from the endoplasmic reticulum/cis-Golgi to the medial/trans-Golgi network. In addition, the majority of intracellular LPL was catalytically inactive, since LPL specific activity (units/mg LPL protein) in cld heart, kidney, and brain was reduced 80-97%. In contrast to the severe impairment of lipase posttranslational processing and secretion, cld mouse plasma contained normal levels of another secretory N-linked glycoprotein, adipsin, with its oligosaccharide chains fully processed to the complex form. Thus, the cld mutation appears not to globally disrupt the secretion of all N-linked glycoproteins, but rather selectively impairs LPL and HL at points essential to their normal intracellular transport and secretion.

Animals↗
PubMed1990

The response of lipoprotein lipase to feeding and fasting. Evidence for posttranslational regulation.

The regulation of adipose tissue lipoprotein lipase (LPL) was examined in rats fed or fasted overnight, and was found to be controlled posttranslationally. LPL catalytic activity decreased by 50% after fasting while LPL mRNA levels and rates of synthesis increased nearly 2-fold; enzyme mass remained unchanged. The distribution of LPL within the endoplasmic reticulum (ER) and Golgi/post-Golgi secretory pathway was assessed by differentiating between LPL high mannose and complex forms. After fasting, the majority of LPL is in the high mannose ER form (65%, 0.97 micrograms/g wet weight tissue), whereas the LPL complex form comprises only 35% (or 0.52 micrograms/g). After refeeding, however, the Golgi-derived LPL complex form predominates (65%, 1.03 micrograms/g) over the high mannose ER form (35%, 0.55 micrograms/g). Kinetic analysis suggests that high mannose LPL disappears with a half-life of t0.5 = 40 min in both fed and fasted rats, indicating that the redistribution of LPL mass during feeding/fasting does not arise by differential retention within ER. Instead, the fractional catabolic rate of complex LPL within the Golgi/post-Golgi secretory compartment can be calculated to be 3.5-fold greater in fasting. In heart, changes in LPL activity in response to feeding/fasting are also not due to differences in mRNA levels or rates of synthesis. Based on these findings, a model of LPL posttranslational regulation is proposed and discussed.

Adipose Tissue↗
PubMed1990

A prospective study of delirium in hospitalized elderly.

The prevalence, risk factors, and outcomes of delirium were studied in 229 elderly patients. Fifty patients (22%) met criteria for delirium; nondelirious elderly constituted the control group. Abnormal sodium levels, illness severity, dementia, fever or hypothermia, psychoactive drug use, and azotemia were associated with risk of delirium. Patients with three or more risk factors had a 60% rate of delirium. Delirious patients stayed 12.1 days in the hospital vs 7.2 days for controls and were more likely to die (8% vs 1%) or be institutionalized (16% vs 3%). Illness severity predicted 6-month mortality, but the effect of delirium was not significant. Delirium occurs commonly in hospitalized elderly, is associated with chronic and acute problems, and identifies elderly at risk for death, longer hospitalization, and institutionalization. The increased mortality associated with delirium appears to be explained by greater severity of illness.

Activities of Daily Living↗
PubMed1990

Fast processing of black and white films used in the EM lab.

Kodak black and white film emulsions 4489, 4162, 2415, TMAX-100, TMAX-400, MPD-4 and RPC-651 can be developed in less than 10 minutes on a film processor, quickly printed on resin coated paper and dried with auto-processor and dryer. Adjustments to the ASA (ISO) to compensate for increased contrast with auto-processing are described.

Microscopy, Electron↗