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Biomedical subjects

J M Peters

Publications and source records attributed to J M Peters.

At least 217 records · Page 12Linked to original sources
PubMed1982

[Positron tomographic study of the behavior of 13N-labeled nitrous oxide in the human brain].

The synthesis of 13N-labelled nitrous oxide was made following NICKLES' method. After a partial denitrogenisation by breathing pure oxygen for 3 min, the subject inhaled a bolus of 13N-labelled nitrous oxide diluted in 2 l of oxygen (a mixture of 5% 13N2O and 95% O2). After an apnea of 30 sec the subject began to breathe in a closed respiratory system containing a mixture of 10% N2O and 90% O2. Eight images of the brain taken at level OM + 3 in 4 subjects showed an important uptake in the cerebellum and in the frontal and temporal cortex. Six min after inhalation of the bolus, the radioactivity in the cerebellum showed a clear decrease, whereas little decrease was observed in the frontal cortex and only a slight decrease in the temporal cortex. In order to suppress the activity due to the vascular comportment, an experiment was performed under the same conditions as the previous one, but using sodium pyrophosphate containing tin and 25 mCi of Tc-99m pertechnetate. The correction factors vary from 0.394 to 0.894 depending on the R.O.I. The activity curves after correction showed a predominance in the frontal cortex. It can therefore be concluded that some specific zones of the brain are receptive to N2O and in particular the frontal cortex. These results were compared with the data obtained from the electrophysiological recording of the frontal region of the brain (C.N.V.: Contingent Negative Variation).

Adult↗
PubMed1982

Evaluation of respiratory effects in miners and millers exposed to talc free of asbestos and silica.

Miners and millers of talc ore, free from asbestos and silica, were examined for respiratory effects. A study of 116 subjects included the modified British Medical Research Council respiratory symptom questionnaire, simple spirometry, chest radiography, and limited examination of the chest. A one-year follow-up evaluation was performed on 103 subjects. Of the 12 subjects whose chest radiographs showed small round or irregular opacities (perfusion 1/0 or greater), five had never smoked cigarettes. Pulmonary function values at the time of the initial study were less than predicted and the rates of loss of FEV1 and FVC greater than expected. These differences were in part attributed to cigarette smoking but were greater than predicted from that source alone. There was evidence of an exposure effect after adjusting for cigarette smoking and we conclude that these workers have been affected by their exposures. No clear interaction between smoking and exposure could be identified. Populations such as this will need to be studied for longer periods to determine what current dust levels are safe.

Chemical Industry↗
PubMed1982

Absence of respiratory effects in subjects exposed to low concentrations of TDI and MDI.

One hundred seven subjects from a polyurethane plastic manufacturing plant have been followed over a five-year period with measurements of forced expiratory volume in 1 s (FEV1), and questionnaires on respiratory symptoms and smoking habits. Environmental concentrations of toluene diisocyanate and diphenyl methyl diisocyanate were extensively monitored to provide accurate estimates of the upper-limits of exposure of the subjects. Current mean levels of FEV1 in this population were higher than those predicted for healthy subjects. The five-year change in FEV1 did not exceed that expected from aging. No acute change in FEV1 could be demonstrated over the course of a Monday either before or after a two-week vacation. No improvement in ventilatory function was observed over the vacation period. The presence of cough or sputum was related to smoking but was not related to isocyanate exposure. The results indicate that exposure of workers to extremely low levels of isocyanates (time-weighted average concentrations of the order of 0.001 parts per million [ppm]) is not associated with chronic respiratory symptoms or effects on ventilatory capacity. The results suggest that isocyanates can be controlled to the point of eliminating effects as measured by these techniques.

Air Pollutants↗
PubMed1982

Occupational epidemiology: detection of cancer in the workplace.

There are fundamental approaches that can be used by health professionals to study the contribution of occupational exposures to cancer occurrence. It would be helpful for clinicians who see patients with cancer to be aware of the methods used to identify those types of cancer that are related to work. Such physicians may be asked by companies or unions to collaborate on the design of epidemiologic studies in work settings or to assist in interpreting results, or they may be consulted by patients from such work environments. Understanding these approaches is essential in order to anticipate, detect and prevent cancer caused by occupational exposures.

Epidemiologic Methods↗
PubMed1981

The occupational and environmental health history.

Occupational and environmental diseases frequently masquerade as routine medical disorders. Yet environmental factors rarely enter into the clinician's differential diagnosis. This article provides a sequence of steps that can be used by the practicing physician for detecting occupational diseases: Step 1: Routine screening questions for all patients (List of job titles? Exposure to fumes, dusts, chemicals, loud noise, or radiation? Temporal relationship of the chief complaint to activities at work or at home?). Step 2: Consideration of sources of exposure (workplace or home surroundings). Step 3: Identification and handling of the hazardous agent. Step 4: Follow-up, consultation, and resolution of the problem. Equipped with this approach, the clinician can play an important role in the detection and prevention of occupational- and environmental-related diseases.

Diagnosis, Differential↗
PubMed1981

Screening for occupational health hazards in the rubber industry. Part I.

Multiphasic health testing (MHT) is often offered to populations of workers usually with the objective of identifying individuals who may be ill. Results are typically not analyzed in relation to estimates of workplace exposure. We describe the results of combining MHT with industrial hygiene assessment of workplace exposures as a method of identifying possible health hazards rather than merely potentially ill individuals. MHT was offered to all production and maintenance workers employed at a tire manufacturing plant. Of 954, 744 participated. We measured worker exposure to respirable particulates, solvent vapor, and noise. We computed the frequency of positive screens among workers classified by exposure and compared these frequencies with expected values adjusted for confounding variables including age, sex, race, and smoking and drinking habits. Workers exposed to higher concentrations of respirable particulates exhibited signs of respiratory and gastrointestinal morbidity. Workers exposed to emissions from heated, uncured rubber undergoing plastic deformation reported chest tightness on return to work. We conclude that combining MHT with assessment of workplace exposure is a valid method for identifying possible occupational health hazards.

Environmental Exposure↗
PubMed1981

Screening for occupational health hazards in the rubber industry. Part II: health hazards in the curing department.

Multiphasic health testing was provided to 744 rubber workers at a tire manufacturing plant. Sixty-two white males from this population had worked longest in the curing department. Personal exposure to respirable particulates was measured for curing press operators. Outcome on screening tests for curing workers was compared with that of 280 white males at this same plant who had never worked in departments known to include jobs where they could have been exposed to respiratory health hazards. Employment in the curing department is associated with shortness of breath, chest tightness, wheeze, loss of FEV-1 and FVC, decline of FEV-1/FVC, and tingling and numbness in the extremities. These associations are stronger with increased duration of employment in the curing department. This paper further demonstrates the potential for using multiphasic health testing combined with measurements of workplace exposure for identifying occupational health hazards.

Adult↗
PubMed1979

Pulmonary function in firefighters: acute changes in ventilatory capacity and their correlates.

A group of 39 firefighters was examined during routine firefighing duty. Following smoke exposure the average decrease in one-second forced expiratory volume (FEV1.0) was 0.05 litre (137 observations). This decline in FEV1.0 was related to the severity of smoke exposure as estimated by the firefighter and to the measured particulate concentration of the smoke to which he was exposed. Decreases in FEV1.0 in excess of 0.10 litre were recorded in 30% of observations. Changes in FEV1.0 resulting from a second exposure to smoke on the same tour of duty were greater when smoke exposure at the previous fire was heavy. The repeated episodes of irritation of the bronchial tree that have been documented in this investigation may explain the origin of the previously observed chronic effect of firefighting on respiratory symptoms and pulmonary function.

Adult↗
PubMed1979

Hormonal effects on rat mammary gland in vitro.

The mammogenic and lactogenic effect of various hormones on rat mammary gland has been studied in vitro using an organ culture technique. The effects have been assessed mainly by light microscopy. The study has been confined mainly to the effects and interactions of the lactogenic protein hormones, corticosteroids and progesterone. It establishes the importance of the presence of insulin and serum and of the type of serum for the hormonal effects in vitro. These effects have been studied mainly on the explants obtained from 13 days pregnant rats. In addition explants from non-pregnant rats and at various stages of pregnancy and lactation were studied.

Adrenal Cortex Hormones↗
PubMed1979

Effect of anesthetics on mortality and kidney lesions caused by hypotension.

Unanesthetized rats and rats anesthetized with a number of anesthetics were bled according to different bleeding schedules. In rats bled for 60 min against 30-50 mm Hg marked protection against mortality and the occurrence of kidney lesions was obtained with pentobarbital-Na, enflurane, halothane and methoxyflurane. Less protection was provided by diethylether while little or no protection was obtained with ethylurethane, trichloroethylene and ketamine. Protection was afforded by pentobarbital-Na in the dose range of 50 mg/kg to 6.2 mg/kg. Slight protection was afforded by dehydrobenzperidol. If pentobarbital-Na was administered after the bleeding the protection was slight. At bleeding pressures below 30 mm Hg the protective effect disappeared for all anesthetics used. Protection was not correlated with either depth of anesthesia, hypotensive effect or reduction of the maximum bleeding volume. However, a correlation was found between protective effect and the retardation of bleeding and the prolongation of survival time caused by the different anesthetics.

Anesthetics↗