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Biomedical subjects

R S Bernstein

Publications and source records attributed to R S Bernstein.

At least 37 records · Page 2Linked to original sources
PubMed1984

Nonoccupational exposures to indoor air pollutants: a survey of state programs and practices.

A national survey of health department activities in 1982 revealed that 32 states (63 per cent) had a program or person(s) responsible for evaluating exposures to one or more nonoccupational indoor air pollutants (NIAPs). Only four states (8 per cent) had existing or proposed NIAP exposure standards. Twenty-nine (57 per cent) of the states had a program to evaluate nonoccupational exposures to formaldehyde, but these varied widely. There is a need for coordinated, consistent approaches to defining and controlling emerging environmental public health problems such as indoor air pollution.

Air Pollutants↗
PubMed1983

Ocular effects following the volcanic eruptions of Mount St Helens.

Three hundred thirty-two ophthalmologists examined 1,523 patients with immediate ocular complaints following the 1980 eruptions of Mount St Helens. Loggers working up to 18 months in environments with high concentrations of volcanic ash were compared with a control group of loggers without volcanic ash contact. Although the ash particles acted as ocular foreign bodies, the small particles were apparently well tolerated for the most part, except for acute irritation. Patients with contact lenses or sicca syndrome had the most frequent ocular complaints. To date, no long-term ocular effects have been noted secondary to volcanic ash exposure.

Adult↗
PubMed1983

Changes in humoral immunologic parameters after exposure to volcanic ash.

Occupational exposure to volcanic ash from Mount St. Helens continues during the salvaging of trees in the high dust blow-down area of Washington. We studied the effects of volcanic ash exposure on the level of humoral immune factors IgG, IgA, IgM, C3, C4, and ANA (antinuclear antibody) in a group of volcanic ash-exposed loggers shortly after the major eruption and one year later. Comparisons with similar levels in nonexposed, similarly employed, matched loggers were made. C3 and C4 levels were significantly lower at both time periods in the exposed loggers when compared to the reference group. No differences between groups were observed at either time period for the immunoglobulin levels or ANA. The exposed loggers did show a marked decrease (not seen in the reference group) in serum IgG levels after 1 yr of exposure to the volcanic ash. They likewise showed a significant mean increase in IgA, while the reference group had a mean increase in IgM after 1 yr. These data suggest that exposure to volcanic ash may affect humoral immunologic parameters.

Adult↗
PubMed1983

Exposures to respirable, airborne Penicillium from a contaminated ventilation system: clinical, environmental and epidemiological aspects.

Symptoms compatible with hypersensitivity pneumonitis (HP) in two of fourteen employees in a clerical office prompted an investigation of their work environment. Forced-air heater-cooler units which had not been properly maintained were implicated when they were found to be grossly contaminated with predominantly Penicillium molds. Air-sampling for viable, respirable-size particulates in the affected office and an unaffected office in the same building demonstrated a 50- to 80-fold excess in the number of colony-forming-units per cubic meter of air in the affected office. Persistent alveolitis was documented by repeated bronchoalveolar lavage, gallium scan, and other studies in one affected worker whose peripheral lymphocytes underwent blast transformation in response to Penicillium antigens obtained by air-sampling in the work environment. The other affected worker had asthma, presumably exacerbated by exposures to a variety of inhaled environmental irritants and antigens. Despite a documented reduction of airborne fungi to background exposure levels after clean-up of the forced-air units, the worker with persistent alveolitis has had occasional recurrences of symptoms consistent with HP. Further research is needed to establish health guidelines for control of occupational and non-occupational exposures to respirable fungal organisms which may contaminate cooling, heating and humidifying systems in these settings. A multidisciplinary method of approach to such research is described.

Air Microbiology↗
PubMed1983

Prediction of the resting metabolic rate in obese patients.

Resting metabolic rate (RMR) was measured in 154 women and 48 men before the beginning of a weight reduction program. In both sexes there were significant univariate correlations between RMR and fat-free mass, body fat, weight, fat cell weight, and fat cell number (from total body water). Women also showed significant correlations between RMR and fat cell number (from total body potassium), free triiodothyronine index, and fasting and postglucose insulin levels. Multiple regression analysis showed that both fat-free mass and fat cell weight and number were significant predictors of RMR. The contribution of fat-free mass was three to five times greater per kg than that of body fat. There was no significant contribution of thyroid hormones or insulin to the prediction of RMR. Fat cell number and fat cell weight were significant predictors of RMR, whether determined from body water, body potassium, or a formula using both water and potassium. There was no significant difference in regression coefficients between men and women. Thus the difference in RMR between the sexes is probably caused by the higher proportion of fat-free mass in men. The effect of age was small and not statistically significant.

Adipose Tissue↗
PubMed1982

Improved insulin responsiveness in rat adipose tissue pieces cultured with charcoal-treated albumin and oxygen.

In an effort tao simulate the effects of insulin on fat cells prepared from fresh adipose tissue, pieces of epididymal adipose tissue were cultured in a medium containing charcoal-treated bovine serum albumin (BSA) with a gas phase of 100% O2. Using this system, the insulin effect on [1-14C]glucose oxidation was retained, in contrast to previous results in culture with untreated BSA in room air. Basal [1-14C]glucose oxidation was similar to fresh tissue, and insulin stimulated oxidation by 137%. In contrast to the effects of this culture system on [1-14C]glucose oxidation, tissue cultured with charcoal-treated BSA had lower basal rates of [U-14C]glucose utilization and 2-deoxyglucose uptake than either cells from fresh tissue or from tissue cultured with untreated BSA. The insulin effect on both of these measures was similar for the two culture systems and lower than for fresh tissues. Rates of lipolysis were increased in both types of cultured fat cells. Thus the improvement in [1-14C]glucose oxidation is presumably an effect on the pentose phosphate shunt, does not reflect a change in glucose transport or overall glucose utilization, and is not caused by a reduction in free fatty acid levels.

Adipose Tissue↗
PubMed1981

Mount St Helens eruptions, May 18 to June 12, 1980. An overview of the acute health impact.

Thirty-five known deaths were caused by the landslide and lateral blast of the May 18 eruption of Mount St Helens and at least 23 persons are missing. In 18 of 23 cases that reached autopsy, asphyxiation from ash inhalation was the cause of death. A rapidly established hospital surveillance system detected increases in the number of emergency room (ER) visits and admissions for asthma and bronchitis in communities with the heaviest ashfall after the May 18 eruption and the eruptions on May 25 and June 12. There were also increases in the number of ER visits for ash-related eye complaints in some areas. laboratory studies indicated that the May 18 ash was not acutely toxic, but the respirable portion contained 3% to 7% of crystalline free silica, a potential pneumoconiosis hazard to certain heavily exposed occupational groups. Continuing volcanic activity of Mount St Helens and future eruption of other volcanoes in the Cascade Range may pose a variety of health hazards, including blast, ashfalls, flooding, damage to public utilities, and possible psychosocial effects.

Asphyxia↗
PubMed1981

Absence of impaired glucose utilization in adipocytes from rats fed a carbohydrate-free, high protein diet.

Glucose utilization was studied in isolated adipocytes from rats fed a mixed (51% carbohydrate, 30% fat, 19% protein), high fat (81% fat, 19% protein) or high protein diet (30% fat, 70% protein). Despite similar food intake, rats on the high protein (HP) diet had smaller epididymal fat pads than the other two groups. The reduction in fat pad size was caused by small and variable reductions in both cell size and cell number. Fat cells from rats on the high fat (HF) diet had the previously reported reduction in pentose phosphate shunt activity in the absence and presence of insulin, and marked diminution of de novo fatty acid synthesis. Lactate release was elevated in the absence of insulin. There was no insulin stimulation of glucose uptake, CO2 production, glyceride-glycerol production or lactate release in these adipocytes. However, significant stimulation of fatty acid synthesis was seen. There was no impairment of glucose uptake or utilization in cells from rats on the HP diet despite the absence of dietary carbohydrate. Indeed, 14CO2 produced from glucose-l-14CO2 produced from glucose-1-14C was increased in these adipocytes. Thus the impaired glucose utilization in rats on the high fat, carbohydrate-free diet is due solely to the fat content of the diet.

Adipose Tissue↗
PubMed1979

Augmented lipolysis in rat adipose tissue upon repeated exposure to epinephrine.

A perfusion system was used to investigate the lipolytic response to epinephrine of minced epididymal fat pads from fed and 24-hr fasted rats. Epinephrine was infused at a final concentration of 1 X 10(-6) M for 60-min periods. Basal glycerol release from tissue and cells of fed animals was 3 mumoles/min/ml of sample. Epinephrine stimulated lipolysis 20-fold in tissue pieces. There was an additional two-fold increase during a repeated epinephrine infusion after 30 min with buffer alone. In contrast, tissue from fasted rats showed no difference upon successive infusions of epinephrine. Isolated cells of fed and fasted animals also produced peaks of equal magnitude on both exposures to epinephrine. Preincubation of fed tissue with anti-insulin serum did not abolish the augmented response to the hormone. Preincubation of the fed tissue for 90 min with omission of the first epinephrine exposure did not produce an augmented response. It is concluded that exposure of adipose tissue to 1 X 10(-6)M epinephrine will produce augmented stimulation of lipolysis on a second exposure. Fasting and isolation of cells abolishes the augmented response by a mechanism which does not involve removal of insulin from the fat cell.

Adipose Tissue↗
PubMed1979

Adipose cell morphology and control of lipolysis in a patient with partial lipodystrophy.

A previously unreported patient with partial (cephalothoracic) lipodystrophy is described. Glucose tolerance and plasma lipids were normal, but plasma insulin increased to 340 muU/ml during an oral glucose tolerance test. Plasma free fatty acids were appropriately suppressed by oral glucose, insulin, and nicotinic acid, and were increased by infusion of norepinephrine. The lipolytic responses was also normal in response to two stimuli for endogenous catecholamine release: upright posture and 2-deoxyglucose infusion. There was a gradual development of postural hypotension in response to upright posture despite appropriate reflex tachycardia. Anhidrosis was present over the lower half of the body during this test, in a distribution corresponding to the area of adipose tissue hypertrophy. Anhidrosis was also seen in this region in response to warm ambient temperature. Adipose cells from the atrophic area were smaller than those from the hypertropic area, but the atrophic cells were only 65% of the volume of the hypertrophic cells by two different methods. Thus, loss of cells occurred. Glucose-1(-14)C utilization and in vitro lipolysis were similar in the two cell preparations; the difference were explicable by cell size and did not suggest a metabolic abnormality. Counts of unmyelinated nerves were similar in the two areas. These findings indicate that in this patient the lipodystrophy was associated with normal fat cells and an autonomic dysfunction. However, the findings cannot completely explain the pathogenesis of her disorder. Loss of fat cells, rather than symmetrical shrinkage, occurred in the upper half of the body.

Adipose Tissue↗
PubMed1979

Insulin insensitivity and altered glucose utilization in cultured rat adipose tissue.

Glucose utilization was studied in isolated fat cells prepared from rat adipose tissue which had been cultured for 18 hr in TC 199 medium. When 1% bovine serum albumin (BSA) was in the culture medium, basal rates of (14)CO(2) and [(14)C]triglyceride production from [1-(14)C]glucose were markedly depressed and there was no effect of insulin. With 4% BSA, basal (14)CO(2) production was the same as in cells prepared from fresh tissue and basal triglyceride production was greatly increased. Insulin effect on these cells was minimal. One-minute uptake of [(14)C]2-deoxyglucose was stimulated by 800-1000% in fresh cells and 300-500% in cells cultured with either 1% or 4% BSA. Oxidation of [U-(14)C]glucose showed a much smaller impairment in cultured cells than for [1-(14)C]glucose, suggesting that the pentose phosphate shunt was more severely impaired than glycolysis. Glyceride-glycerol production was increased in cultured cells relative to preculture (fresh) cells. There was no effect of insulin in the culture medium in any of these systems. Rates of free fatty acid and glycerol release were markedly increased in cultured cells, especially when insulin was present in the culture medium. The acute antilipolytic effect of insulin was retained, so that insulin in the test incubation decreased lipolysis by 40-80%. Nevertheless, cell-associated fatty acids were increased in cultured cells and FFA/albumin ratios in the medium often reached potentially toxic levels. The reduction in pentose phosphate shunt activity, lipogenesis, and insulin effect resembles other models of insulin insensitivity. The impaired metabolism is probably due to an intracellular defect. A possible toxic role of either intracellular or extracellular fatty acids cannot be excluded. This system should be a useful model in which to study the cellular mechanisms of insulin insensitivity in adipocytes.-Bernstein, R. S. Insulin insensitivity and altered glucose utilization in cultured rat adipose tissue.

Animals↗
PubMed1978

DNA-dependent RNA polymerases from Artemia salina: decreasing polymerase activities and number of polymerase II molecules in developing larvae.

Embryos and larvae of the brine shrimp, Artemia salina, provide a useful biological system for biochemical studies of animal development. Dormant encysted embryos can be cultured readily in the laboratory to provide large quantities of free-swimming nauplius larvae. The rate of synthesis of all classes of RNA in swimming larvae declines markedly between 24 and 72 h after immersion of dormant embryos in sea water. Nuclei were isolated from 24-72 h larvae and RNA polymerase activity was measured under conditions in which the nuclei remained intact. Total RNA polymerase activity of isolated nuclei decreased in parallel with RNA synthesis in vivo. RNA polymerases were solubilized from nuclei and fractionated by chromatography on DEAE-cellulose. The levels of both RNA polymerases I and II also decreased in parallel with RNA synthesis in vivo. The specific activity of highly purified RNA polymerase II was determined by comparison of enzyme activity with the mass of RNA polymerase II subunits displayed on SDS gels. The specific activities of RNA polymerase II preparations from 24 and 72 h larvae were identical. The number of polymerase II molecules was estimated from the mass of the subunits. The number of molecules per nucleus declined from 20,000 at 24 h to 3500 at 72 h.

Age Factors↗