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Biomedical subjects

R R Martin

Publications and source records attributed to R R Martin.

At least 145 records · Page 8Linked to original sources
PubMed1979

Quantitative nasal cultures from carriers of Staphylococcus aureus: effects of oral therapy with erythromycin, rosamicin, and placebo.

Serial quantitative nasal cultures were performed on 87 healthy nasal carriers of Staphylococcus aureus, who were randomly assigned to 7 days of oral therapy with erythromycin, rosamicin (an investigational macrolide antibiotic), or placebo. Staphylococcal carrier rates decreased during therapy with both antibiotics; however, erythromycin was significantly more effective in lowering carrier rates than was rosamicin. The anti-staphylococcal effects of both antibiotics were similar when the mean numbers of S. aureus isolated from positive cultures during therapy were compared. Side effects to each regimen were minimal.

Adolescent↗
PubMed1979

Assay of serum tobramycin levels with the Bactec 460.

Serum tobramycin levels of synthetic and patient specimens were determined by the Bactec 460. The results were compared with those obtained from the same specimens by radioimmunoassay. These studies suggest that assays performed by either method should be run in duplicate or triplicate to achieve maximum accuracy. The studies also suggest that results obtained by the Bactec method are at least as reliable as those obtained by the radioimmunoassay method.

Anti-Bacterial Agents↗
PubMed1979

A four-year follow-up study of lung mechanics in smokers.

We performed a prospective study of pulmonary function in 21 smokers, 9 ex-smokers, and 12 nonsmokers. The smokers and ex-smokers were preselected, because they were participants in a smoking cessation clinic. An average interval of 4 years separated the first and second (follow-up) studies. The smoking group showed a significant decrease in maximal expiratory flow measured at low lung volume, loss of elastic recoil, increase in lung compliance, increase in total lung capacity; increase in the ratio of residual volume to total lung capacity, and an increase in the ratio of functional residual capacity to total lung capacity. The ex-smokers showed changes similar to those of the smokers, but of lesser magnitude. The nonsmoking group demonstrated few changes in function during the study interval. Commonly measured parameters of function, including the ratio of the forced expiratory volume in 1 sec to the forced vital capacity and the maximal expiratory flow after exhalation of 50 per cent of the vital capacity, did not change significantly in any group. Sensitive tests of lung function were abnormal in a very high percentage of the combined group of smokers and ex-smokers when measured at the time of the second study; only a small number of abnormalities in these parameters were noted in the nonsmoking group. We conclude that there was a deterioration of lung function in smokers far in excess of that predicted by age. These changes suggest the development of emphysema and were predictable for the group as a whole by a high prevalence of abnormality of dynamic compliance, closing volume, maximal mid-expiratory flow, and residual volume at the time of the initial study.

Adult↗
PubMed1979

Relationship between the single-breath N test and age, sex, and smoking habit in three North American cities.

This report describes a collaborative study conducted in Montreal, Canada, Portland, Ore., and Winnipeg, Canada, to establish the relationship between the single-breath N2 test and age, sex, and smoking and to determine the prevalence of functional abnormalities in these populations. In nonsmokers, age-related regressions for closing volume, closing capacity, and the slope of phase III obtained from the single-breath N2 test, plus the ratio of the I-s forced expiratory volume to the forced vital capacity had very similar slopes, suggesting that differences in geographic location, climate, air pollution, and occupation had no effect on lung function detectable by these tests. Among the 6 city/six groups there was no systematic difference in the prevalence of functional abnormalities between the cities, but closing capacity expressed as a percentage of total lung capacity was abnormal most often in men and the slope of the alveolar plateau was abnormal most often in women. The prevalence of respiratory symptoms within different smoking categories was similar in the 3 cities. Although the number of cigarettes smoked had a significant effect on every test except the ratio of the I-s forced expiratory volume to forced vital capacity in men, the effect of age was considerably greater than the effect of smoking, and the dose-response relationship was weak. We conclude that additional factors may interact with smoking to place a smoker at risk of developing chronic airflow limitation.

Adult↗
PubMed1979

Effects of renal failure on leukotaxis.

Effects of renal failure and experimental azotemia on in vitro leukocyte migraton were studied. Migration of normal leukocytes in sera from patients with untreated renal failure was regularly decreased, while sera from patients on chronic dialysis exerted no inhibitory effect. Serial sera obtained from two patients starting chronic dialysis exhibited a gradual decrease and ultimate disappearance of the serum inhibitory effect. Experimental azotemia serum supported increased migration of normal leukocytes. Leukocytes from renal failure patients migrated normally when incubated in autologous uremic serum or in normal homologous serum. These results provide evidence that serum from untreated renal failure patients inhibits the in vitro migration of normal leukocytes. This inhibitory capacity is apparently correctable by hemodialysis.

Acute Kidney Injury↗
PubMed1979

Enzyme release and morphological changes in leukocytes induced by mechanical trauma.

Polymorphonuclear (PMN) leukocytes exposed to mechanical trauma in vitro will release enzymes both from azurophilic and specific granules at shear stress levels of between 75 and 150 dyn/cm2 for 10 min. In addition, at these shear stresses the leukocyte count in whole blood decreased only slightly and the number of ruptured leukocytes on Wright-stained blood films increased significantly. At higher shear stresses, enzyme release and leukocyte damage increased monotonically. Transmission electron microscopy evaluation of sheared PMNs revealed that remaining intact cells had minor morphological changes at stresses of 150 dyn/cm2. They were characterized by clublike cytoplasmic potrusions, spherical shape, and a circumferential distribution of cytoplasmic granules. At higher shear stresses (600 dyn/cm2) cell destruction was marked. Intact PMNs contained fewer cytoplasmic granules, a large number of vacuoles, and condensed nuclear chromatin. These studies show that PMN morphology and function are at least as sensitive to mechanical trauma as similar platelet alterations seen in other studies.

Alkaline Phosphatase↗
PubMed1978

A human plasma component that binds benzo(a)pyrene.

A component capable of binding benzo(a)pyrene was measured in plasma from cigarette smokers and nonsmokers. This plasma fraction was found to have a high specificity of binding to benzo(a)pyrene, bound benzanthracene competitively with benzo(a)pyrene, and was positively correlated (r = 0.861, p less than 0.001) with the capacity of the individual subject's lymphocytes to be induced for AHH activity in culture. An inverse correlation (r = -0.957, p less than 0.001) between the presence of the plasma component in lung cancer patients and the capacity of lung cancer patients' lymphocytes to be induced in culture is unexplained at this time. A benzo(a)pyrene-binding fraction was not found in induced or uninduced cultured lymphocytes from smokers or nonsmokers, or in homogenates of lung excisional tissue from smokers with or without primary lung cancer.

Aryl Hydrocarbon Hydroxylases↗
PubMed1978

Hemophilus influenzae pneumonia in adults.

Hemophilus influenzae pneumonia was diagnosed in 41 adult patients based on cultures of blood, pleural fluid or transtracheal aspirate. Bacteremia occurred in all age groups, but was most frequent in patients over the age of 50 years with severe underlying pulmonary disease. Chest films usually demonstrated multisegmental or multilobar infiltrates without evidence of cavitation. Pleural involvement was evident in half of the patients, although empyema occurred infrequently. Mortality was almost always associated with serious underlying diseases and bacteremia. Encapsulated strains of H. influenzae (usually type B) were identified in 18 of 22 (82 per cent) patients. The use of transtracheal aspirations and the adoption of routine subculturing of blood cultures on chocolate agar appear to be important factors in our increased recognition of this disease.

Adolescent↗
PubMed1978

Effect of ventilation with different gas mixtures on experimental lung air embolism.

In six anesthetized, curarized and mechanically ventilated dogs, air was infused via a jugular vein at 0.1 cm3/kg/min for 25 min. This induced a progressive increase in pulmonary artery pressure (Pap) while arterial PO2 (PaO2) and end tidal PCO2 (PETCO2) decreased. Systemic arterial pressure, dynamic lung compliance and total pulmonary resistances were not affected. Changes tended to plateau by 20 min with a peak increase in Pap of 80 +/- 13% and decrease in PaO2 and PETCO2 of 22.2 +/- 2.8% and 14.5 +/- 2.1% respectively. When embolization was stopped these values returned to control levels within 30 min. During air infusion (at 20 min) some dogs were switched from ventilation with air to ventilation with the following gas mixtures: SF680%-O220%, He80%-O220%, N2O80%-O220%. During the final 5 min of air infusion. He and, to a greater extent, N2O breathing results in an immediate and marked further increase in Pap and decrease in PaO2 and PETCO2. In contrast SF6 produced rapid improvement in these parameters with return to near control levels. The recovery time after stopping infusion was greatly shortened with SF6 but was unaffected by He or N2O. These results are explained by different rates of gas transfer between the intravascular bubbles and the various alveolar gases. These findings show that ventilation with SF6 results in marked improvement in the gas exchange abnormalities produced by air embolism.

Animals↗
PubMed1978

Beta-lactamase production and resistance to beta-lactam antibiotics in Nocardia.

Although ampicillin has been suggested as a useful agent for the treatment of nocardiosis in man, little is known regarding the presence of beta-lactamase in Nocardia or its possible role in determining resistance to ampicillin and the other beta-lactam antibiotics. We have evaluated 55 isolates of Nocardia for susceptibility to five beta-lactam antibiotics and for the presence of beta-lactamase. Nocardia were resistant to penicillin G, cloxacillin, and cefazolin, but 27 and 62% were susceptible to 3.1 and 25 mug of ampicillin per ml, respectively. Almost 90% of these ampicillin-susceptible or intermediate strains were also susceptible to carbenicillin. The combination of ampicillin and cloxacillin was synergistic against many ampicillin-resistant strains. Beta-lactamase was detected in 89% of Nocardia isolates when intact cells were used and in six of six strains after cell fractionation. This beta-lactamase was most active against penicillin G and ampicillin, with lesser activity against carbenicillin and cephaloridine. These studies suggest that beta-lactamase may be present in all clinical isolates of Nocardia and that mechanisms of antimicrobial resistance other than or in addition to beta-lactamase are responsible for resistance of Nocardia to ampicillin and carbenicillin.

Ampicillin↗
PubMed1978

Flow dependence of gas distribution and the pattern of inspiratory muscle contraction.

We measured regional distribution of xenon-133 boli at 0.25, 0.75, and 1.5 l/s in four normal seated subjects during inspirations performed predominantly with intercostal and accessory muscles (IC) or with the diaphragm, accompanied by outward abdominal motion (Ab). In six additional subjects we inferred the topographical distribution of helium boli during similar breaths and flow rates from the slope of the alveolar plateau recorded during a slow expiration (less than 0.5 l/s). Distribution of the helium boli was studied during natural as well as IC and Ab inspirations. At each of the flow rates IC breaths distributed relatively more of the inspired bolus to upper lung regions than did Ab inspirations. Natural breaths at 0.25 l/s resulted in distributions similar to those of Ab inspirations, whereas at 1.5 l/s the distribution approached that of IC inspirations. A three-compartment model, representing upper, middle, and lower lung regions, was used to simulate bolus distribution. The experimental data showed substantial departure from predictions based on regional time constants alone. However, additional small differences in applied pressure (less than 0.50 cmH2O) between the regions satisfactorily accounted for the gas distribution.

Abdominal Muscles↗
PubMed1978

Topographical ventilation and perfusion distribution during IPPB in the lateral posture.

We measured topographical ventilation and perfusion distribution in the gravity field using 133Xe in 5 normal subjects either during natural breathing or during intermittent positive pressure ventilation (IPPB) in the lateral decubitus posture. The ratio of ventilation of upper regions to that of lower regions increased from 0.61 +/- 0.10 (mean +/- SE) during natural breathing to 0.95 +/- 0.08 during IPPB. In contrast, the ratio of regional perfusion was unchanged in the 2 conditions. Consequently, distribution of regional ventilation-perfusion ratios became less homogeneous during IPPB. Whereas during natural breathing the ratio of ventilation-perfusion of upper regions to that of lower regions was 1.09 +/- 0.18, during IPPB this ratio was 1.52 +/- 0.14. Despite the differences in regional ventilation distribution between natural breathing and IPPB, analysis of multiple-breath 133Xe washouts measured at the mouth did not reveal any difference. The results are consistent with the hypothesis that the magnitude of diaphragmatic tension is the main determinant of topographical ventilation distribution in the lateral posture.

Humans↗
PubMed1978

Immunoglobulin secreting cells in normal human bronchial lavage fluids.

Immunoglobulin secreting cells were quantitated in the bronchial lavage fluids of 12 normal volunteers and compared with immunoglobulin secreting cells in peripheral blood, by a reverse hemolytic plaque assay. The mean number of cells secreting immunoglobulin (Ig)G in bronchial lavage fluids was 489 per million lymphocytes vs. a mean of 175 IgG secreting cells per million lymphocytes in peripheral blood (P < 0.02). The mean number of IgA secreting cells in bronchial lavage fluids was 633 per million lymphocytes as compared to 100 per million lymphocytes in peripheral blood (P < 0.005). Thus, compared to peripheral blood, cells from the lavage fluids were relatively enriched for both IgG and IgA secreting cells. However, IgA secreting cells were the major class of immunoglobulin secreting cells in bronchial lavage fluids, whereas IgG secreting cells predominated in peripheral blood. The prominence of IgA secreting cells in bronchial lavage fluids was further demonstrated by a mean ratio of IgA/IgG secreting cells in bronchial lavage fluids of 1.26 compared to a ratio in peripheral blood of 0.57 (P < 0.02). Cells secreting IgM were identified in only four of seven bronchial lavage fluid samples studied but in all peripheral blood samples. IgE secreting cells were not present in normal peripheral blood but could be demonstrated in 5 of 11 lavage fluid specimens. Thus, cells actively secreting immunoglobulins can be identified in the lower bronchial-alveolar tree of normal human subjects. Cells secreting IgG, IgA, or IgM may function in local lung defenses against infection; cells secreting IgE may contribute to hypersensitivity reactions in the lung.

Adult↗