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Biomedical subjects

R R Martin

Publications and source records attributed to R R Martin.

At least 163 records · Page 9Linked to original sources
PubMed1977

Treatment of hospita-acquired infections with amikacin.

Amikacin was used in the treatment of 56 serious gram-negative infections in 54 patients of whom 47 survived. In six of the seven nonsurvivors, the infections were under control at the time of death. The clinical isolates were multiple drug-resistant gram-negative organisms, with Proteus rettgeri being most common. Forty-five (80%) of these infections were nosocomial in origin, and the genitourinary tract was the source in 39 (70%). Complications directly related to amikacin therapy were few and suggested renal or otologic toxicity. In this series of patients, amikacin appeared to be of therapeutic benefit in the treatment of serious gram-negative infections.

Adolescent↗
PubMed1977

Induction of aryl hydrocarbon hydroxylase in human pulmonary alveolar macrophages and peripheral lymphocytes by cigarette tars.

Cigarette smoking is associated with alterations in pulmonary alveolar macrophages (PAMs), including increased cytoplasmic inclusions and induction of the aryl hydrocarbon hydroxylase (AHH) system. Nonpigmented PAMs from nonsmokers were able to ingest and accumulate pigment from lysed PAMs of smokers, however, this pigment did not induce AHH activity in either PAMs or peripheral lymphocytes. In contrast, the cigarette tars significantly induced AHH levels in PAMs and in peripheral lymphocytes from either nonsmokers or smokers. This provides further evidence that components in cigarette smoke can explain the in vivo induction of AHH documented in cells from smokers.

Aryl Hydrocarbon Hydroxylases↗
PubMed1977

In vitro induction of aryl hydrocarbon hydroxylase in human pulmonary alveolar macrophages by benzanthracene.

Aryl hydrocarbon hydroxylase (AHH) was induced in human pulmonary alveolar macrophages (PAMs) cultured in the presence of benzanthracene. Time and dose--response curves were established for in vitro induction of this enzyme system in PAMs. In addition, a positive correlation was noted between the level of AHH activity in freshly lavaged PAMs and the in vitro inducibility of the enyzme in these cells from either nonsmokers or cigarette smokers. Measurements of the inducibility of AHH in cultured human PAMs provide an experimental system suitable for studying the mechanisms responsible for the initiation of pulmonary carcinogenesis.

Adult↗
PubMed1977

Effects of noise and increased vocal intensity on stuttering.

The present study was designed to assess the effects of increased vocal level on stuttering in the presence and absence of noise, and to assess the effects of noise on stuttering with and without a concomitant increase in vocal level. Accordingly, eight adult stutterers spoke in quiet with normal vocal level, in quiet with increased vocal level, in noise with normal level, and in noise with increased level. All subjects reduced stuttering in noise compared with quiet conditions. However, there was no difference in stuttering when subjects spoke with normal compared with increased vocal level. In the present study, reductions in stuttering under noise could not be explained by increases in vocal level. It appears, instead, that reductions in stuttering were related to a decrease in auditory feedback. The condition which resulted in the largest decrease in auditory feedback, speaking in noise with a normal level, also resulted in the largest decrease in stuttering.

Adult↗
PubMed1977

Disk diffusion susceptibility testing of Nocardia species.

The effectiveness of 13 antimicrobial agents against 51 clinical isolates of Nocardia was determined with use of agar dilutions and disk diffusion method. Amikacin inhibited less than 90% of isolates and, like the other aminoglycosides, showed good correlation between minimal inhibitory concentrations and sizes of zones of inhibition around the disks. Both sulfisoxazole and trimethoprim-sulfamethoxazole were very active, although they required a 2- to 3-log lower inoculum for demonstration of susceptibility. Results with the two sulfa disks were variable, but they did allow distinction between sensitive and intermediate strains. All of the isolates of Nocardia were inhibited by 6.3 microng of minocycline; however, the degree of susceptibility could not be determined by zone diameters. Only two-thirds of these clinical isolates of Nocardia grew rapidly enough to be assayed by either susceptibility method.

Anti-Bacterial Agents↗
PubMed1977

In vivo effects of josamycin, erythromycin, and placebo therapy on nasal carriage of Staphylococcus aureus.

Healthy nasal carriers of Staphylococcus aureus were randomly assigned to one of three treatment regimens: josamycin (1.5 g/day), erythromycin stearate (1.0 g/day), or placebo, each administered orally for 7 days. Quantitative nasal cultures were obtained from each subject at intervals before, during, and after treatment. All 25 placebo-treated subjects had positive nasal cultures for S. aureus at all culture intervals. Both josamycin and erythromycin were equally effective in reducing the carrier rates and in decreasing the total numbers of S. aureus isolated from subjects with positive cultures during treatment. No increase in in vitro antibiotic resistance was detected in isolates obtained after therapy. Both antibiotics were well tolerated, and toxicity was not encountered with either drug.

Anti-Bacterial Agents↗
PubMed1977

Diaphragmatic contraction and the gradient of alveolar expansion in the lateral posture.

Using 133Xe we measured the vertical distribution of regional volume in four subjects in the lateral decubitus posture at 20, 40, 60, and 80% of vital capacity (VC). To study the influence of diaphragmatic tone, all measurements were performed either when transdiaphragmatic pressure (Pdi) was low, i.e., diaphragm was "relaxed" (RD) or during voluntary diaphragmatic contraction (VDC). The latter was achieved by tensing the abdominal muscles while keeping the glottis open. Under both conditions the gradient of alveolar expansion tended to be curvilinear, with a discontinuity at the level of the mediastinum. At all lung volumes the difference in regional volume between dependent and nondependent lung regions was less during VDC than during RD. At 70% total lung capacity (TLC) this difference, expressed as percent of regional TLC (%TLCr), decreased from 19.7 +/- 1.7 (mean +/- 1 SE) %TLCr during RD to 3.9 +/- 1.5% TLCr during VDC. It is likely that diaphragmatic tension influences the pleural pressure gradient and regional volume distribution 1) by modifying the transmission of the abdominal hydrostatic pressure gradient to the thorax, and 2) by an upward displacement of the mediastinum.

Diaphragm↗
PubMed1977

In vivo gas trapping induced by nitrous oxide.

Repeated vital capacity (VC) breaths in 17 anesthetized and curarized dogs induced a small but significant increase in residual volume (RV). This trapping was greatly enhanced when a mixture of 80% N2O and 20% O2 (N2O-O2) was used instead of air. VC breaths with N2O-O2 also increased closing volume, closing capacity and closing pressure determined with 133Xe. Successive quasi-static pressure volume (PV) curves of the lung showed a shift to the right at high lung volume and to the left at low lung volume. Again these changes were more impressive with N2O-O2). The PV curve of the chest wall was unchanged. Insufflations from RV were necessary to produce the gas trapping. Increase in RV was positively related to the size of the inspired volume, to N2O concentration, and inversely related to the inspiratory flow rate. Vagotomy, intravenous isoproterenol, and intravenous propanolol did not alter the phenomena. We propose that these observations can be explained by the presence of foam in the airways and that N2O leads to an increase of foam by osmotic liquid shift into the bronchioli, and/or to an increase in bubble's size by gas diffusion.

Animals↗
PubMed1977

Normal human bronchial immunoglobulins and proteins: effects of cigarette smoking.

Selected proteins were compared in bronchial lavage fluids recovered from 36 healthy nonsmokers and 19 healthy cigarette smokers. Although fluids lavaged from smokers contained 4 times as many cells (more than 80 per cent macrophages) as fluids from nonsmokers, there were no quantitative differences between the two groups in immunoglobulin A, a1-antitrypsin, a2-globulin, transferrin, or albumin content. However, immunoglobulin G content of bronchial fluids from smokers was twice as high as that from nonsmokers. This selective increase in immunoglobulin is compatible either with stimulated local bronchial immunoglobulin production or the selective exudation of plasma immunoglobulin into alveolar spaces in response to inhaled cigarette smoke.

Adult↗
PubMed1977

Regional lung function in pleural effusion.

In 6 seated subjects with small unilateral pleural effusion without other radiographic abnormality, we measured regional lung function using xenon-133, comparing the function of the lung on the side with the effusion to the function on the contralateral side. When both lungs were equilibrated with Xe, count rates were lower at the base with the effusion, indicating either collapse or displacement of lung in these regions. Regional lung expansion was measured as fractions of regional total lung capacity: regional functional residual capacity/regional total lung capacity and regional residual volume/regional total lung capacity. The distribution of boluses inhaled slowly from residual volume was also measured, In all subjects the results were the same on the side with the effusion as on the other side. These findings were compatible with effective static pleural pressure being the same on both sides and suggest that the reduction in count rate at the base with effusion was due to displacement rather than compression of lung. We also measured regional washout half-times during dynamic breathing and found them prolonged in regions underlying effusion, indicating that dynamic ventilation of these areas was reduced. We postulated that the dynamic pressure swings applied to these regions were decreased by the effusions.

Adult↗