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Biomedical subjects

E D Palmes

Publications and source records attributed to E D Palmes.

At least 19 recordsLinked to original sources
PubMed1987

Explanation of pressure effects on a nitrogen dioxide (NO2) sampler.

When nitrogen dioxide (NO2) samplers were exposed at several reduced pressures, it was found that the sampling rate was correspondingly decreased; that finding did not agree with accepted diffusional theory. When the experiments were repeated using water vapor as the gas and molecular sieve as the sorbent, the observed sampling rates were in very good agreement with diffusional theory. These findings demonstrated that the pressure effect was not common to all diffusional samplers and suggested that there might be an alternate explanation for the results with NO2-triethanolamine (TEA). The best possibility appeared to be the dehydration of TEA that takes place at reduced pressures. That this is a very significant factor was demonstrated by simultaneous exposure to identical concentrations of NO2 at 1 atm and 50% or 0% relative humidity. In dry air the sampling rate was equivalent to that found previously at about 1/10 atm. The earlier results can be satisfactorily explained as indirect rather than direct effects of reduced pressure.

Diffusion↗
PubMed1986

Airborne particles, their use in the respiratory system to measure air flow, function, and clearance.

Nonhygroscopic monodisperse particles can be used to estimate airway dimensions within chosen regions of the respiratory tract. These dimensions correspond well with those measured in inflation-fixed lungs. The dispersion of a bolus of airborne particles on inhalation and exhalation is very sensitive to the dimensions of the airways through which the bolus passes, yielding indices of dispersion that provide sensitive indicators of changes in airway dimensions, eg, with smoking. The rates of clearance of particles from the lungs are determined using gamma-labelled particles whose lung retention is determined by external measurements. There are major differences between the deep lung and the ciliated airways. Changes in clearance rates are caused by disease or inhaled intoxicants such as cigarette smoke. At lower levels of irritant exposure, an acceleration of clearance rate is observed, while higher doses and longer periods of exposure produce decreased rates. It is suggested that aerosol techniques may have useful clinical applications; approaches are suggested for such applications.

Adult↗
PubMed1986

A simple mathematical model for diffusional sampler operation.

A simple mathematical model of the molecular basis for the function of a diffusional sampler for dilute mixtures of gaseous contaminants in supporting gases is presented. The model is based on the movement of single molecules of the contaminant between sections of a tubular diffusion path on a step-by-step basis; the length of the step and of each section of the tube are equal to the mean free path, lambda, under the specified conditions. When the model is used, the coefficient of diffusion, D, can be calculated from lambda and the average velocity, v, of the contaminant molecule. Both lambda and v were calculated independently using equations which involved the minimum number of assumptions. The value of D so estimated was of the same order as that in the literature, differing by a factor of less than 2. It should be emphasized that the model represents a statistical, thermodynamic approach to understanding diffusional samplers, and its utility is independent of the means of estimating lambda and v for specific gas pairs.

Diffusion↗
PubMed1985

Carbon dioxide production by individual mice as an index of behavioral and metabolic activity.

A noninvasive method for simultaneous real-time determination of spontaneous locomotor activity (LA) and CO2 production (as minute volume expired CO2, or VECO2) in mice is described. As an apical measure of overall metabolic activity, VECO2 proved sensitive to changes in many physiological processes, including behavioral activity. In normal mice, LA (as photobeam breaks) and VECO2 were positively correlated (r = 0.73), and stable over repeated daily tests. Food deprivation for 18 hr overnight increased LA while decreasing VECO2. Stimulation of peripheral sympathetic activity, either by exposure to cold air or by injection of epinephrine, increased VECO2 without affecting LA. Intoxication with pentobarbital produced a biphasic change in both measures: anesthetic doses increased LA and VECO2 during induction and recovery, and reduced them during the period of anesthesia itself. These results characterize VECO2 as an easily quantifiable, composite index of behavioral and metabolic activity in mice. This measure, along with its co-variation with LA, may provide better information about toxic effects than any single screening test.

Animals↗
PubMed1985

Effects of toluene inhalation on carbon dioxide production and locomotor activity in mice.

Rapid and noninvasive tests of locomotor activity (LA) and carbon dioxide production (minute volume expired CO2, or VECO2) in mice were sensitive to the effects of inhaled toluene. Compared to sham exposures, toluene at 100 ppm had no effect on LA or VECO2; at 1000 and 3000 ppm, LA increased during exposure, while VECO2 was suppressed for 6 to 24 min at the beginning of exposure. In a nominal 10,000-ppm exposure, toluene levels were increased from 1000 to 10,500 ppm in 60 min. At these levels, toluene abolished LA at concentrations above 8000 ppm, and suppressed VECO2 throughout exposure. During recovery from toluene-induced narcosis, both LA and VECO2 were elevated above control. In other studies, groups of mice inhaled toluene daily at 0, 100, 1000, or 3000 ppm, 5 hr/day for 8 or 90 days, and were tested individually 30 to 90 min after termination of exposure. Under these conditions, toluene decreased postexposure VECO2 for 1-2 weeks, altered the weekly pattern of change in VECO2, and did not affect LA. No effects of repeated, daily exposure to toluene were observed on body weight. These results demonstrate the utility of the present method to detect changes in LA and metabolic rate resulting from toluene inhalation, and suggest that different mechanisms are involved in the behavioral and metabolic responses to toluene inhalation.

Animals↗
PubMed1985

A rapid air titration method for determining SO2 concentration in inhalation chambers.

A rapid air titration method for determining SO2 concentration in inhalation chambers has been validated using the pararosaniline-formaldehyde (PRA) method of West and Gaeke. This air-titration (iodate) method is an adaptation of iodometric methods using a starch indicator. Potassium iodate and an excess of potassium iodide are used in the reaction. Sampling is completed in ten minutes or less and concentration is calculated by use of a simple formula. Linear equations were derived over the range of concentrations from 0.5 to 100 ppm SO2 for uncorrected iodate bubbler results, data corrected for tandem bubbler concentrations and data corrected for mean iodate bubbler efficiency. Linear correlation with the PRA method over this range was 0.999 for all three sets of data.

Atmosphere Exposure Chambers↗
PubMed1979

Personal sampler for NOx.

A personal sampler system for NOx (NO + NO2) and NO2 has been developed for monitoring workplace air. The NO2 sampler previously reported from this laboratory uses triethanolamine to trap NO2 which diffuses through a tube of appropriate dimensions. The NOx sampler contains the same elements as the NO2 device, but it is also fitted with a chromic acid impregnated disc; this disc converts NO to NO2 which is then trapped by the triethanolamine along with preformed NO2. The trapped NO2 in all cases is determined as nitrite colorimetrically and NO is measured by difference between the NOx and NO2 values. The NOx sampler gives accurate and reproducible results if the chromic acid disc is in place for 24 hours or less; it is necessary, therefore, to insert and remove the disc within reasonably short times before and after sampling. We believe, however, that this operation will not be a serious problem for the user.

Air Pollutants↗
PubMed1978

Species variability in plasma S-sulfonate levels during and following sulfite administration.

It has been shown that S-sulfonate compounds (R-S-SO-3) are produced by the action of sulfite on reactive disulfide bonds [4,5]. Plasma S-sulfonate production was determined as a function of sulfite ingestion and intraperitoneal injection in rats, mice and rhesus monkeys. The tendency of these species and of the rabbit [8] to produce S-sulfonates in plasma was related to the availability of sulfite and of reactive disulfide bonds and to the stability of plasma protein S-sulfonates. The rhesus monkey and the rabbit accumulated plasma S-sulfonates much more readily than did the rat, while the mouse produced little, if any, under the same test conditions. Plasma protein S-sulfonate fractions in the rat and rhesus monkey were characterized by half-lives of approximately 4 and 8 days respectively. The sensitivity and precision of the analytical method for plasma protein S-sulfonate were improved by incorporation of 35S into the outer sulfur atom of the S-sulfonate moiety (R-S-35SO-3).

Animals↗
PubMed1978

Effects of DDT on stable laboratory mouse populations.

Four stable laboratory mouse populations were established; each contained approximately 400 mice of both sexes and all ages postweaning living in a single cage, as well as neonates caged in separate nesting boxes with their dams. Two were used to determine the effects of continuous exposure to a dietary level of 100 ppm DDT while the other two served as controls. The results indicated a significant decrease (p less than or equal to 0.05) in neonatal survival (lactation index) within 20 wk after the beginning of exposure to the toxicant in one of the exposed populations and by 30 wk in the other. This deleterious effect of the DDT continued through each succeeding generation. On the other hand, improved postweaning survival in DDT-fed mice was noted. Histological examination showed no tumors in test or control animals; other pathology was seen more frequently in control than in test animals.

Animals↗
PubMed1976

Atmospheric derivatives of anaesthetic gases as a possible hazard to operating-room personnel.

During surgical procedures in which nitrous oxide (N2O) anaesthesia was administered there was an increased concentration of both nitric oxide (NO) and nitrogen dioxide (NO2) in operating-room air. Preliminary studies suggest that the use of certain devices (e.g., electric cauteries, X-ray machines) capable of releasing energy in the operating-room produce the oxidation of nitrous oxide. Further evaluation of gas phase reactions of anaesthetic agents within the operating-room appear warranted, particularly in relation to the occupational risks of operating-room personnel.

Abnormalities, Drug-Induced↗
PubMed1976

Personal sampler for nitrogen dioxide.

A new type of personal sampler for gases in air, originally reported from this laboratory, has been adapted to measurement of NO2. The sampler depends on the transfer of NO2 by diffusion to a triethanolamine coated collector at the sealed end of a tube; the open end of the tube is exposed to the test environment. The devices are accurate, light, simple to use and have very good shelf life before and after sampling.

Air Pollutants↗
PubMed1975

Variability in the size of airspaces in normal human lungs as estimated by aerosols.

Measurement of persistence, expressed as half-life (t1/2), of a monodisperse aerosol during breath holding was interpreted as an indirect estimate of the size of intrapulmonary airspaces in healthy subjects. Within subject variation of t1/2 measured over a period of nearly two years was small (coefficient of variation 7-7 to 11-5%). Mean effective airspace diameters were calculated from the aerosol t1/2 values using the settling term from the equation of Landahl (1950). Calculated mean airspace diameters ranged from 0-30 to 0-79 mm for 36 males and from 0-40 to 0-62 mm for 12 females. Airspace diameters correlated poorly with age, height, weight, and lung volumes. These results suggest marked differences in airways geometry in subjects with similar heights and lung volumes.

Adult↗