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Biomedical subjects

R D Fairshter

Publications and source records attributed to R D Fairshter.

At least 37 records · Page 2Linked to original sources
PubMed1985

Airway hysteresis in normal subjects and individuals with chronic airflow obstruction.

Specific conductance (sGaw) was measured without prior pharmacological induction of bronchoconstriction before and 5-10 s after a total lung capacity (TLC) volume history in normal subjects and in individuals with chronic airflow obstruction (CAO); increased sGaw after inspiration to TLC was considered evidence of airway hysteresis. Lung elastic recoil [Pst(L)] was also measured before and after inspiration to TLC. In the normal subjects 1) prebronchodilator sGaw increased significantly, whereas Pst(L) decreased significantly after inspiration to TLC; 2) modulators of cyclooxygenase activity had no significant effects on sGaw responses to deep inspiration; and 3) airway hysteresis diminished after inhalation of atropine or metaproterenol. In the CAO group 1) prebronchodilator sGaw and Pst(L) decreased significantly after inspiration to TLC, and 2) bronchoconstriction after deep inspiration diminished after inhalation of atropine or metaproterenol. This study demonstrates that normal airways exhibit hysteresis even without alteration of resting airway tone and that airway hysteresis is impaired in CAO.

Adult↗
PubMed1985

Partial and maximal expiratory flow-volume curves in normal and asthmatic subjects before and after inhalation of metaproterenol.

The effects of deep inspiration upon expiratory flow rates and response to inhaled metaproterenol were studied in normal and asthmatic subjects using partial (PEFV) and maximal (MEFV) expiratory flow volume curves. Routine pulmonary function tests and specific conductance were also measured. Prior to administration of metaproterenol, 18 of 24 normal subjects and 11 of 24 asthmatic subjects (p 0.05) had higher flow rates on MEFV than on PEFV curves. The 11 volume history responsive asthmatic subjects showed better lung function and more density-dependence of expiratory flow than the other 13 asthmatic subjects; furthermore, the effect of lung inflation was significantly larger in the volume history responsive asthmatic subjects than in the volume history responsive normal subjects. Responses to inhaled metaproterenol were much larger on PEFV than MEFV curves; nevertheless, differences between normal and asthmatic subjects in metaproterenol responsiveness were less using PEFV curves. Thus, the use of PEFV curve measurement did not facilitate the detection of individual asthmatic responses to inhaled metaproterenol.

Adult↗
PubMed1984

Effect of dimethylthiourea on paraquat toxicity in rats.

We evaluated the utility of dimethylthiourea ( DMTU ), a hydroxyl radical scavenger, as potential therapy for paraquat poisoning. Seventy-five male Sprague-Dawley rats were divided into four groups ( DMTU -paraquat, paraquat, DMTU , control) and studied for up to 10 days. Clinical observations (dyspnea, weakness), mortality, hepatic and renal function tests, body weights, and histologic studies were performed. There was no mortality in the DMTU and control groups although various histologic and biochemical studies suggested that DMTU may be both hepatotoxic and nephrotoxic. In contrast, 74% of DMTU -paraquat rats and 39% of paraquat rats died (p less than 0.01). In addition, toxicity was clearly earlier in the DMTU -paraquat group than in the paraquat group. Hence, rather than being protective, treatment with dimethylthiourea was associated with increased mortality in paraquat-poisoned rats.

Animals↗
PubMed1984

Physiologic correlates of airway collapse in chronic airflow obstruction.

Forty percent of 89 patients with chronic airflow obstruction (CAO) demonstrated maximum expiration flow-volume (MEFV) patterns consistent with sudden collapse or marked narrowing of large central airways. In contrast, 43 percent of the CAO patients demonstrated a curvilinear (C) pattern; the remainder (17 percent) were intermediate. Volume displacement plethysmography indicated that the airway collapse (AC) pattern was influenced by, but was not solely, a gas compression artifact. Airway collapse patients had more obstruction and hyperinflation than C patients and also had decreased diffusing capacity, absence of density dependence, reduced lung recoil, and no effort dependence of airflow. Bronchodilator administration in AC patients typically produced large reduction of residual volume and increase of vital capacity, with a smaller increase of airflow. These data suggest that AC patients have significant, partially reversible peripheral airways obstruction plus emphysema. Possible determinants of AC include reduced central airway support, increased peripheral resistance, loss of lung recoil, and increased pleural pressures during forced expiration. The MEFV contour appears to evolve from normal to curvilinear to the AC pattern as the severity of airflow obstruction worsens.

Aged↗
PubMed1984

Pulmonary pathology in renal transplant recipients.

Studies of the lungs have revealed multiple functional and histopathological abnormalities in patients with chronic renal failure, but data following renal transplantation are extremely limited. We examined postmortem data from 20 transplant patients and found pulmonary abnormalities in most patients. The number of pulmonary abnormalities noted in patients with poor transplantation, averaged 5.3 per patient. The corresponding number was significantly less (3.4 per patient) in the group with good transplant renal function, surviving more than one year after transplantation. Pulmonary calcification, fibrosis, and hemosiderosis were found in several patients in the former group but in none of the latter group. This observation suggests reversibility of these pulmonary abnormalities with successful renal transplantation.

Adult↗
PubMed1983

Nontuberculous mycobacterial disease. Experience in a southern California hospital.

The experience with nontuberculous mycobacterial disease at an "acute-care" hospital in southern California between 1971 and 1981 is reported. Forty-five patients with nontuberculous mycobacterial or Mycobacterium bovis-caused disease were identified by retrospective review. Of these, 31 patients (69%) had pulmonary infection alone, nine (20%) had cervical lymphadenitis, two (4%) had disseminated disease, two (4%) had cutaneous infection, and one had soft tissue infection. Nonmycobacterial pulmonary disease was noted in 15 (33%) of the patients and underlying malignant neoplasms were noted in eight (18%). Symptoms most frequently reported at initial examinations of patients with pulmonary disease were cough, weight loss, sputum production, and fatigue. Response to therapy was more successful in patients with Mycobacterium kansasii-caused disease than in those with Mycobacterium avium-intracellulare-caused pulmonary disease. We conclude that nontuberculous mycobacterial disease is not rare in the general hospital setting in southern California.

Adolescent↗
PubMed1983

Postprandial exercise-induced anaphylaxis.

A variety of systemic reactions associated with exercise are increasingly being recognized. We studied an atopic individual whose job-related activities involved strenuous running that often terminated in an episode of syncope and hypotension preceded by cutaneous pruritus, warmth, urticaria, and angioedema. These attacks occurred only after meals, but no foods appeared to elicit symptoms without subsequent exercise. The subject underwent three exercise challenges in the laboratory under the following conditions: (1) fasting state, with heat-dissipating clothing. (2) fasting, with heat-retention clothes, and (3) after a meal. Blood pressure decreases and minimum skin reactivity were observed for (1) and (2), and reproduction of syncope, hypotension, and further cutaneous manifestation were observed only after (3). Venous and arterial plasma determinations for complement activation (C4, C4d, and CH50) and histamine before, during, and after exercise were not abnormal. Although other vasodepressor mediators may have been liberated, at least part of the mechanism for postprandial exercise-related syncope may be attributed to a shift of blood flow to the splanchnic as well as skeletal muscle vasculature.

Adult↗
PubMed1983

Frequency and spectrum of pulmonary diseases in patients with chronic renal failure associated with spinal cord injury.

We reviewed autopsy records from 20 patients with long-standing spinal cord injury and chronic renal failure. Only 1 patient had normal pulmonary findings at autopsy. Acute and chronic pulmonary diseases were found in 16/20 and 17/20 patients, respectively. Pneumonia and fluid overload were the most common acute diseases. Interstitial and pleural fibrosis were the most common chronic diseases. However, a variety of illnesses including pulmonary amyloidosis, calcification, and arteriosclerosis were also found. Arterial blood gas studies indicated a high prevalence of hypoxemia. We concluded that significant pulmonary abnormalities are present in almost all spinal cord injury-chronic renal failure patients.

Adult↗
PubMed1983

A comparison of incremental exercise tests during cycle and treadmill ergometry.

We evaluated a short-duration maximum exercise test by comparing a 15-s incremental exercise protocol with a 1-min incremental method. Twenty normal men and women were studied using cycle and/or treadmill ergometry. In subjects tested on both exercise devices, anaerobic threshold and maximal oxygen uptake (VO2max) were higher for both protocols on the treadmill than on the cycle ergometer (P less than 0.001). However, when the 15-s and 1-min tests were compared using the same device (treadmill or cycle), there were no significant differences between protocols in anaerobic threshold or maximum exercise values of minute ventilation, respiratory rate, tidal volume, VO2max, oxygen pulse, and peak expiratory flow rate. Linear regression analyses indicated differences between the 15-s and 1-min protocols when cardiopulmonary measurements were related to power; however, the two protocols were comparable when cardiopulmonary data were related to oxygen uptake. Comparisons between protocols or between exercise devices were not systematically different in large vs small individuals, or in men vs women. Short-duration incremental exercise tests appear to be reliable, practical methods for assessing exercise performance in normal individuals.

Exercise Test↗
PubMed1983

Partial and complete maximum expiratory flow-volume curves in asthmatic patients with spontaneous bronchospasm.

Bronchodilatation follows a deep inspiration in normal subjects with pharmacologically induced bronchoconstriction. To determine to what extent this occurs in asthmatic patients with spontaneous bronchospasm, we obtained partial (PEFV) and complete (MEFV) maximum expiratory flow volume curves in 20 adults (helium-oxygen responders and nonresponders) and 13 children with asthma. We measured maximum expiratory flow at 25 percent of forced vital capacity from the partial (Vmax - p) and complete (Vmax - c) flow-volume curves and expressed this relationship as the Vmax - p/Vmax - c ratio. Three of the adult subjects and one of the children had a V max-p/V max-c less than 1.0. Following inhalation of nebulized bronchodilators, none of the children or adults had a Vmax - p/Vmax - c ratio less than 1.0. Reasons for Vmax - p to be higher than Vmax - c include bronchoconstriction, decreased lung elastic recoil following a deep inspiration, and time dependence of maximum expiratory flow due to lung inhomogeneity. We conclude that asthmatic patients with spontaneous bronchospasm are only seldom able to obtain bronchodilation following a deep inspiration.

Adolescent↗
PubMed1982

Ultrastructural evidence of pulmonary capillary endothelial damage from paraquat.

Because of lack of agreement concerning the toxicity of paraquat to the pulmonary microvasculature, we have undertaken an electron microscopic study of lungs of paraquat-treated rats. Rats were injected with paraquat or sterile water (controls) intraperitoneally; the animals were then killed at 24-h intervals for 10 days post-injection. In the control animals, lung ultrastructure remained normal throughout the study. In treated animals, the initial evidence of alveolar epithelial injury occurred 24 h post-paraquat. By 48 h, severe fragmentation and desquamation of membranous pneumocytes occurred, and both alveolar and interstitial edema were present. Epithelial damage was maximal 72-96 h post-paraquat. Pulmonary capillary endothelial abnormalities were less extensive than the alveolar epithelial lesions. Endothelial damage was first observed 48 h post-paraquat. In endothelial cells on the septal (thick) side of the capillaries, the number of pinocytotic vesicles was significantly increased (P less than 0.05) from 48 to 96 h post-paraquat. In endothelium adjacent to damaged epithelium, abnormalities included hydration, fragmentation, discontinuity, and widened intercellular junctions; these were maximal 72-96 h post-paraquat. Although other mechanisms are probably important, damaged pulmonary capillary endothelium seems to be a factor favoring paraquat-induced pulmonary edema.

Animals↗
PubMed1982

Chronic airflow obstruction in a patient with pigeon breeder's lung: prevalence of IgE antibodies to avian antigens.

We report a case of pigeon breeder's lung in which chronic airflow obstruction and not restrictive lung disease was predominant. The patient's disease was severe enough to require hospitalizations twice to reverse respiratory failure. Helium-oxygen flow volume curves were consistent with a peripheral site of flow limitation, and immunoserological studies disclosed specific IgE as well as precipitating antibody responses to pigeon antigens. Immunological studies on 18 other patients with pigeon breeder's lung demonstrated a prevalence rate of specific IgE antibodies of 78%, a frequency not previously recognized. Exposures to avian antigens must be considered in patients with obstructive lung disease of unknown etiology.

Aged↗
PubMed1982

Lung pathology in chronic hemodialysis patients.

To determine the spectrum and the relative frequencies of different pulmonary diseases in chronic renal failure (CFR) patients, we reviewed autopsy records from 46 chronic hemodialysis patients with end-stage renal disease of various etiologies. Pathological abnormalities were observed in the lungs of all but one patient. Acute and chronic lung diseases were found in 95.7% and 80.4% of subjects respectively. The most common acute diseases were pulmonary infections (pneumonia, lung abscess, empyema) and fluid overload. The most common chronic process was interstitial fibrosis. Other relatively common chronic diseases included pleural fibrosis and/or pleuritis as well as pulmonary arteriosclerosis, hemorrhage, thromboembolism and calcification. The incidences of granulomatous lung diseases, pulmonary amyloidosis and metastatic lung tumors were also higher than expected. Relative incidences of the different pulmonary diseases did not appear to be related to the etiology of CFR; rather, lung abnormalities were common in CFR of all etiologies.

Acute Disease↗
PubMed1981

Inhaled atropine sulfate in acute asthma.

We administered inhaled atropine sulfate to acute asthmatics already receiving therapeutic doses of adrenergic agonists, theophylline, and corticosteroids. Following atropine, hyperinflation diminished whereas vital capacity and expiratory flow rates breathing air and helium-oxygen increased (p less than 0.025 - p less than 0.005). Initial density dependence correlated inversely with changes in density dependence after atropine (r = -0.69, p less than 0.001). We conclude that: (1) inhaled atropine sulfate was effective therapy for acutely ill asthmatics already being treated with multiple antiasthmatic agents; (2) atropine caused large and peripheral airways bronchodilatation, and (3) the predominant site of bronchodilatation after atropine was related to the site of flow limitation before atropine.

Acute Disease↗
PubMed1981

Relationship between sites of airflow limitation and severity of chronic airflow obstruction.

We studied the relationship between sites of airflow limitation and severity of chronic obstructive pulmonary disease. Pre- and postbronchodilator physiologic testing was performed in 30 subjects with chronic airflow obstruction (CAO). Pulmonary function, including the increase in maximal expiratory flow at 50% of vital capacity after helium-oxygen breathing (delta VEmax50), was reduced before and after inhalation of 1.3 mu mg of metaproterenol. Significant correlations were present between values for delta VEmax50 and measurements of expiratory flow (p < 0.001). In subjects with severe CAO (one-second forced expiratory volume less than or equal to 1.2 L; percentage ratio of one-second forced expiratory volume to forced vital capacity < 50%), delta VEmax50 was always abnormally decreased. An inverse relationship was present between initial delta VEmax50 and changes in delta VEmax50 after inhalation of metaproterenol (p < 0.001). These results suggest that the site of airflow limitation becomes progressively more peripheral as CAO worsens, and that severe CAO is usually associated with peripheral sites of airflow limitation.

Aged↗