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Biomedical subjects

L Levin

Publications and source records attributed to L Levin.

At least 55 records · Page 3Linked to original sources
PubMed1985

Injury incidence rates in a paint company on rotating production shifts.

Reports of work accidents and increased absence due to sickness among shift workers have suggested that their work performance and health are adversely affected by interference with the body's normal circadian or biological rhythm. Since the rotating shift is the most disruptive of the work regimens, an investigation was undertaken of the reportable occupational injuries of 1700 paint production and associated employees of one company working only on rotating shift. Their annual accident incidence rates averaged over 10 years were compared to the average annual rate reported by the Department of Labor for the entire United States paint manufacturing industry representing predominately day and non-rotating shift workers. The significance of the hour of the accident incidence rates was tested by chi-square statistics using loglinear models appropriate for null hypotheses that assume no effect due to shift work. The incidence rates of the company studied were lower than those of the U.S. paint industry, suggesting work safety practices uniquely related to the company studied may have predominated. Within the company, however, some time-of-day and circadian effects were indicated by an increased rate of accidents on the night shift, particularly during the last 3 h of the shift.

Accidents, Occupational↗
PubMed1985

Reduction of sympathetic inotropic response after ischemia in dogs. Contributor to stunned myocardium.

Eight open chest dogs underwent 25 min of coronary occlusion to determine whether brief myocardial ischemia disrupts the normal myocardial inotropic response to sympathetic nervous stimulation. If so, this could represent a mechanism contributing to postischemic myocardial dysfunction. Myocardial segment shortening was measured using ultrasonic dimension crystals before and after coronary artery occlusion and reperfusion. Left ansa subclavia stimulation and systemic norepinephrine (NE) infusion were used to test the myocardial inotropic response to neural stimulation and direct exposure to the sympathetic mediator, respectively. Before coronary artery occlusion, base-line preischemic segment shortening (12.5 +/- 1.6%) (SEM) increased during both sympathetic stimulation (20.2 +/- 1.4%) and NE infusion (19.7 +/- 1.1%). The control segment responded similarly. After ischemia and reperfusion there was no significant change in heart rate, aortic or left ventricular pressures, nor changes in control segment shortening. In contrast, shortening in the postischemic segment was markedly reduced compared to baseline (4.1 +/- 2.4%), and no longer responded to sympathetic stimulation (2.4 +/- 2.8%), while responsiveness to systemic NE was maintained (12.9 +/- 2.0%), P less than 0.001, which suggested injury to the sympathetic-neural axis during the period of ischemia. This reduced response to neural stimulation was persistent for up to 2 h after reperfusion. Left atrial or intracoronary infusion of bretylium tosylate, which releases norepinephrine from nerve terminals, resulted in an immediate inotropic response in the postischemic segment, which indicated that total depletion of NE from nerve terminals during the ischemic period had not occurred. Disruption of sympathetic neural responsiveness is likely a component of the mechanism of postischemic myocardial dysfunction whenever there is appreciable sympathetic drive to the heart.

Animals↗
PubMed1984

Occupational exposure to cyclophosphamide.

Several lines of research have demonstrated the risk of occupational exposure of health-care personnel to anticancer drugs. Urine samples from two nurses working in a cancer clinic were analysed for cyclophosphamide (CP) by gas chromatography after they had prepared the drug for treatment. Since the drug might be absorbed through the skin, urine samples from five volunteers were also examined after a solution of CP had been applied topically to the cubital fossa area. Variable quantities of intact CP were identified in samples from the volunteers collected over 24 h, but in most cases the drug was evident only in urine samples given more than 6 h after application. CP was found in several urine samples from the nurses, but the quantities of CP in these samples were not related to the amounts of drug handled. The identity of CP was confirmed by gas-chromatography/mass-spectrometry. CP appeared sooner in the urine samples from the nurses than in those from the volunteers, suggesting a faster route of absorption, perhaps through inhalation of aerosols generated during dissolution of the drug. These findings suggest that the increased levels of mutagenicity observed in urine samples of nurses who worked on oncology wards might have arisen, in part, from metabolites of CP.

Adult↗
PubMed1984

Comparison of muscle and fat wasting in patients suffering from breast and other cancers: an anthropometric study.

An anthropometric study was undertaken to determine muscle and fat areas in 50 cancer patients and 258 control patients suffering from minor conditions, to assess the degree of cachexia in patients with breast cancer, and in patients with other types of cancer. Patients suffering from cancers other than those of the breast showed muscle and fat wasting when compared with matched standard values and when the muscle and fat area measurements were expressed as a percentage of the appropriate mean standard value. Breast cancer patients showed increased muscle and fat area values, irrespective of whether they were in remission, or had progressive disease. This is interesting in view of the strong association between dietary fat intake and breast cancer incidence, and correlates well with present ideas on nutrition and the incidence of breast cancer.

Adipose Tissue↗
PubMed1984

A laboratory evaluation of wipe testing based on lead oxide surface contamination.

Although wipe testing has been used extensively as a measure of surface contamination in industrial hygiene, few scientific studies have been reported to validate the procedure with respect to quantitative recovery, repeatability or methodology. Consequently, a laboratory evaluation of wipe testing with particular attention to the OSHA procedure was undertaken using lead oxide dust as the test contaminant. A dust dispersion system was devised using a Wright dust feeder to produce relatively uniform surface concentrations in an aerosol chamber. Wipe materials included moistened filter paper, commercial paper towels, adhesive paper labels and adhesive tape. The quantitative recovery and repeatability of the wipe procedures were related to surface concentrations and the operational and material variables. Significant improvements in recoveries of up to 90% can be obtained with good repeatability for removable lead oxide dust on non-porous surfaces using moist paper on a fixed test surface area. For porous surfaces, which show significantly lower recovery by all methods, adhesive sampling materials applied at maximum pressure provided an optimum recovery of 77%. The importance of reliable surface contamination measurements in assessing potential health hazards underscores the desirability of improving the demonstrated deficiencies of the OSHA and other wipe sampling procedures.

Air Pollutants, Occupational↗
PubMed1984

Study and models of total lead exposures of battery workers.

In an attempt to establish a more realistic and reliable model for relating environmental exposure measurements to the biological indices of exposure, a study was undertaken to quantify the total sources of lead exposure among lead storage battery workers. In addition to the usual personal and area lead air sampling, quantitative and repeatable measurements of removable lead from work surfaces and the workers' hands and faces were obtained daily for ten consecutive work days in the pasting and battery assembly departments. Mathematical correlations of blood lead and zinc protoporphyrin (ZPP) levels as the dependent variable with the lead exposure sources were derived and demonstrated most strongly as log-log relationships. Statistical analyses by computer programming indicated that the airborne, hand, facial and work surface levels have a high degree of inter-correlation with a very significant positive individual correlation with blood lead levels and a somewhat lower correlation with ZPP. The results suggest that contaminated personal and work surfaces may play a more significant role in toxic occupational and environmental exposures, generally, than had heretofore been demonstrated or suspected.

Adult↗
PubMed1984

The accreditation of academic programs in industrial hygiene.

The American Academy of Industrial Hygiene has initiated a program to accredit academic programs in industrial hygiene. Guidelines, criteria, and procedures to be employed by the Accreditation Committee are summarized, along with a status report of activities currently underway.

Accreditation↗
PubMed1983

Serum amino acids in weight-losing patients with cancer and tuberculosis.

A study of arterial and arterio-venous amino acid concentration differences across the forearm was performed in 19 weight-losing cancer (CWL) patients (9 with lung cancer and 10 with other types of cancer), 8 weight-losing patients with active pulmonary tuberculosis (TWL) and 10 normal controls. Arterial concentrations of many of the amino acids measured were found to be lower in CWL than in TWL patients. In addition, the data suggested a venous excess of amino acids in the CWL patients compared with TWL patients and controls. The increased release of alanine from forearm muscles in the CWL group, together with the low arterial glycogenic amino acid levels, supports the concept of enhanced gluconeogenesis in CWL patients. Low arterial amino acid levels and possible increased release of amino acids from forearm muscle in CWL patients implies enhanced proteolysis with increased central clearance or tumour sequestration of these amino acids, though decreased proteogenesis cannot be excluded in accounting for the venous excesses in this group. Hypocitrullinemia in lung cancer patients was marked, and possible mechanisms to account for this are discussed.

Adult↗
PubMed1983

Occupational dermatitis among hairdressers. A multifactor analysis.

Dermatitis among hairdressers has been recognized as a significant occupational health problem but the occurrence, contributing factors, and control measures have not been comprehensively studied or reported. Consequently, an epidemiologic field study of dermatitis among hairdressers and its relationship to medical history of allergy, frequency of specific product use, sex, and number of years in hairdressing was conducted in the winter of 1982 in four southern New Jersey counties. Work practices and procedures were observed and chemical inventories taken during on-site visits to the participants' beauty salons. The data collected were complied and analyzed using a computerized log-linear statistical procedure. The association between the occurrence of dermatitis and a medically confirmed history of allergy is highly significant (p less than .001) and decreases with increasing numbers of years in hairdressing, indicating perhaps that highly susceptible individuals leave their jobs. There was no significant relationship between dermatitis and the levels of frequency of product use. Means of controlling and preventing occupational dermatitis among hairdressers are discussed. Because of the complexity and diversity of the chemical products used, further research is needed to explore the specific etiological factors of hairdresser's dermatitis.

Dermatitis, Occupational↗
PubMed1983

A review of the health effects of energy conserving materials.

The energy conservation movement has promoted both greater use of insulating materials and the reduction of heat losses by sealing air leaks. The release of volatile or airborne materials from the installation of these building materials under these conditions has resulted in an exacerbated indoor air pollution with the potential for certain health and safety hazards. Consequently, a comparative review of the health and safety hazards, exposure standards, and regulatory action associated with the more commonly used insulating materials with particular respect to current energy conservation measures was undertaken. The materials reviewed included asbestos, urea-formaldehyde foam, polyvinyl chloride, cellulosic insulations, fibrous glass, mineral wool, and vermiculite. Although no longer used, the past installation of asbestos in a friable form is the greatest potential health hazard. The exposure to formaldehyde gas from its release from urea-formaldehyde foam has elicited subjective complaints of sensory irritation and unresolved controversy and regulatory action regarding its toxicity to humans. Lesser health problems have been associated with the more widely used fibrous glass and mineral or rock wools.

Asbestos↗
PubMed1982

Syndrome of inappropriate antidiuretic hormone secretion following dis-dichlorodiammineplatinum II in a patient with malignant thymoma.

A patient with malignant thymoma is reported, in whom the syndrome of inappropriate antidiuretic hormone secretion (SIADH) occurred 36-48 hours after being given cis-Dichlorodiammineplatinum II (CPPD) with a mannitol diuresis. The SIADH was treated by fluid restriction and demeclocycline and subsided after approximately 72 hours. Subsequent courses of CPPD with mannitol diuresis were given with demeclocycline prophylactically and no untoward effects noted. The precise mechanism for the SIADH following the use of CPPD is unknown, but may be life-threatening, especially since preloading with fluid followed by forced diuresis is used when CPPD is given to avoid nephrotoxicity. The patient has survived 37 months, with 24 months of relapse-free survival following treatment with CPPD, irradiation and surgery.

Cisplatin↗
PubMed1982

Hemangiopericytoma of the colon: report of a case and review of literature.

A patient with a hemangiopericytoma of the colon is discussed. This is the second such case reported in the English medical literature. Soon after discovery of the tumor, the patient presented with a colonic intussusception with the tumor serving as the lead point. This was reduced by a hypaque enema, but the intussusception recurred twice more, being reduced again by hypaque enema and finally having to be reduced by colonoscopy. At surgery a left hemicolectomy with primary anastomosis was performed. The microscopic, ultrastructural, and pathologic aspects of hemangiopericytoma are discussed with special attention to lesions of the gastrointestinal tract.

Adult↗
PubMed1982

The value of dorsal column stimulation in multiple sclerosis.

Ten patients with definite and one with probable MS, all markedly inflicted, but with a varying degree of motor and bladder dysfunction were subjected to spinal cord stimulation in a controlled study. None of the patients exhibited appreciable fluctuation in symptoms in the pre-study period. Bladder symptoms were most markedly influenced by electrical stimulation. The reduction in hesitancy and urgency was of great importance to the patients. In 9 of 10 patients reduction in voiding frequency took place, the all over reduction being 8%. Maximum extension torque increased by 9% and flexion torque by 29% during the stimulation when compared to the first placebo period. In selected MS patients, i.e. patients with bladder dysfunction and with a certain muscular reserve, electrical spinal cord stimulation may have an indication.

Adult↗
PubMed1981

Metabolic alterations in cancer. Part II. Protein and fat metabolism.

Intracellular changes in protein metabolism within cancer cells may facilitate cell reduplication, and this may be supported by changes in enzymes responsible for protein synthesis and degradation. Synthesis of ectopic hormones probably reflects genetic de-repression. Increased muscle proteolysis has been reported by some workers in cancer patients, and this may be associated with muscle cells, increased glucocorticoid secretion by the adrenal cortex, increased gluconeogenesis or impaired muscle glycolysis. Decreased proteogenesis has also been reported to occur in the muscles of cancer patients. Although tumour tissue may inhibit muscle proteogenesis, there are as yet no data to suggest a direct tumour-derived ectopic substance which affects muscle proteolysis or proteogenesis. Data regarding serum levels of free fatty acids (FFA) in weight-losing cancer patients are conflicting, although it is likely that abnormally high values are due to liver dysfunction rather than enhanced peripheral lipolysis. Nevertheless, since serum levels may be normal if FFA consumption is increased to the same extent as release, these levels need not indicate overall FFA turnover. If enhanced FFA release from fat stores does occur, this may provide the liver with an energy source required for its increased commitment to gluconeogenesis.

Animals↗