Exercise as a bronchodilator.
Explore the source record for details and available documents.
Airway Resistance↗
Biomedical subjects
S Freedman
Publications and source records attributed to S Freedman.
Alterations in endothelial superoxide dismutase levels as a function of growth state in vitro.
Damage to the retinal vasculature in retinopathy of prematurity is primarily at the level of the growing neovascular front. This clinical observation in combination with experimental observations that correlate the induction of superoxide dismutase (SOD) activity with differentiation led to the hypothesis that the basis for the relative vulnerability to oxygen lies in the relative "undifferentiated" nature of proliferating endothelial cells (EC). To test this hypothesis, an in vitro model of microvascular EC was used and levels of SOD activity were assayed as a function of growth state and differentiation. The SOD activity was elevated significantly in EC that stopped growing as a contact-inhibited monolayer compared with its activity in cells in their log phase of growth. In addition, SOD levels were elevated in microvascular cells that stopped growing and were organized into a network of capillary-like tubes, the ultimate differentiated state of microvascular EC. To understand the mechanism of increases in SOD activity with differentiation, the effect of extracellular matrix synthesized by a confluent monolayer of EC was examined as was artificial growth arrest caused by mitomycin. Both treatments led to an increase in SOD activity over control cells. Thus, it is possible that SOD activity in cells is modulated by information provided from the extracellular matrix and "intracellular" signals that indicate cessation of cell growth. These data support the hypothesis that the growing front of retinal microvessels is more vulnerable to effects of oxygen-induced damage because of their relatively undifferentiated state with respect to the oxygen radical-scavenging enzyme system of SOD.
Adrenal Cortex↗
Characterization of a GTPase-activating protein for the Ras-related Ral protein.
We have demonstrated the presence of a GTPase-activating protein (GAP) for the Ras-related Ral A protein in the cytosolic fraction of brain and testis. This protein, designated Ral-GAP, was distinguished from Ras-GAP by its behavior in two chromatography systems and by the fact that the two GAP proteins did not stimulate the GTPase activity of each others target GTP binding proteins. The lack of effect of Ral-GAP on Ras GTPase activity also distinguished it from the product of the neurofibromatosis gene NF-1. Ral-GAP also differed from Rho-GAP and Rap-GAP by virtue of its elution from a gel filtration column with proteins of Mr greater than 10(6). This was likely an overestimate of the protein's molecular mass, however, since it sedimented in sucrose gradients between standard proteins of 150 and 443 kDa. Ral-GAP failed to promote the GTPase activity of mutant Ral proteins containing amino acid substitutions that in Ras lead to GAP-insensitive proteins.
Animals↗
A comparison of oral and inhaled steroids in patients with chronic airways obstruction: features determining response.
Two trials comparing aerosol and oral steroid treatment were carried out in patients with chronic airways obstruction. All patients had a history of chronic productive cough and an FEV1 less than 70% predicted but did not have episodic or seasonal breathlessness with wheezing. One trial involved 18 outpatients, the other 18 inpatients. Both studies involved three consecutive treatment periods, the first with placebo aerosol, the second with active aerosol (betamethasone valerate, 800 microgram/day), and the third with oral prednisone or prednisolone (30 mg/day). Six patients showed a significant improvement in ventilatory capacity on steroids. Initial assessment included a comprehensive history using a questionnaire, skin tests, blood and sputum eosinophil counts, and chest radiography. In addition, for the inpatients, response to isoprenaline, daily sputum volume, and PaCO2 were measured. Only blood eosinophilia and variability in ventilatory capacity during the placebo period seemed indicative of a likely response to steroids. However, there was a large overlap between various features on assessment in the responders and non-responders, and the management of every patient with chronic airways obstruction should include a controlled trial of steroids. The steroid aerosol produced a good improvement in ventilatory capacity in the responsive patients who were hospitalised and this was thought to be helped by supervision of aerosol technique. Such an aerosol could therefore be used for a steroid trial although oral steroids were found to give a more definitive response.
Administration, Oral↗
Lung volumes and distensibility, and maximum respiratory pressures in thyroid disease before and after treatment.
Lung volumes, static pressure volume curves of the lung, and maximum respiratory pressures were measured in six patients with thyrotoxicosis and three with myxoedema before and after treatment. After treatment three of the thyrotoxic patients had increases in vital capacity of the same order as previously reported, but in contrast to previous reports, the lung volume changes were not associated with, nor due to, concomitant changes in respiratory muscle performance. Static pulmonary compliance increased in four of the six patients. The initial findings were more in keeping with the presence of pulmonary congestion. Only one of the myxoedematous patients had any significant increase in vital capacity after treatment, and in her case this was clearly attributable to increased inspiratory muscle force.
Aged↗
Comparison of findings among residents on Michigan dairy farms and consumers of produce purchased from these farms.
Consumers who had purchased farm products from both quarantined and nonquarantined farms were examined during the cross-sectional clinical survey of 1,029 Michigan residents. Since PBB had inadvertently contaminated cattle and other farm animals, ingestion of meat, milk, eggs and other farm products was thought to have possibly resulted in significant PBB body burdens in some consumers. Findings were considered in comparison with those made among farm residents. Prevalence of symptoms in consumers of farm products from quarantined farms (CQ) was similar to that found in farmers on quarantined farms (FQ); the prevalence was lower in consumers of products from nonquarantined farms (CNQ). Liver function abnormalities were found with similar prevalence in dairy farmers and consumers. Distribution, mean and median values of PBB serum levels in consumers were found to be similar to those of dairy farmers. These results indicate that significant body burdens of PBB had been accumulated by some consumers of farm products in Michigan and that prevalence of symptoms and liver function abnormalities resembled those found among dairy farm residents.
Biphenyl Compounds↗
Unanticipated prevalence of symptoms among dairy farmers in Michigan and Wisconsin.
Adverse human health effects resulting from exposure to polychlorinated biphenyls (PBBs) were unknown until the accidental contamination of Michigan dairy farm animal feed in 1973-1974. Human exposure resulted from the consumption of contaminated meat, milk, dairy products, and eggs. In November 1976, the Environmental Sciences Laboratory conducted comprehensive examinations of 933 farmers and residents in Mighigan who were likely to have consumed farm products contaminated with PBB. A comparison group of 229 Wisconsin dairy farmers were examined in March 1977 and the same scientific and medical staffs that conducted the Michigan survey were responsible and the same procedures used. A complete history of symptomatology by organ system, including year of first onset, duration, frequency, and severity of each symptom was obtained by a physician on all adults examined. Statistical analysis of the prevalence of symptoms at the time of examination or during the preceding year in the Michigan and Wisconsin populations studied found the Michigan group to have a significantly higher prevalence of skin, neurological and musculoskeletal symptoms. The increase was seen among the younger age groups 16-35 and 36-55. Michigan females had a higher prevalence of neurological symptoms than the Michigan males. The existing differences could not be explained without considering an etiologic role for exposure to PBB.
Adolescent↗
Treatment of peptic ulcer: a dilemma.
Explore the source record for details and available documents.
Duodenal Ulcer↗
Rheumatoid factor in a patient with Reiter's disease and aortic incompetence.
Explore the source record for details and available documents.
Adult↗
Changes of smoking habits and cough in men smoking cigarettes with 30% NSM tobacco substitute.
The effects of smoking cigarettes with 30% of the tobacco replaced by NSM tobacco substitute, which lowered their tar and nicotine delivery, were studied by comparing them with the effects of conventional cigarettes in a controlled crossover trial lasting 20 months. Chest symptoms, cigarette consumption, and forced expiratory volume in one second (FEV1) were measured each month. Two-hundred men began the trial and 159 completed it. The test cigarettes were acceptable to all but one of the men. In a subsample of 35 men estimates of nicotine intake were obtained from monthly analyses of cigarette stubs. On changing from NSM to control cigarettes six of the 17 men, who were accustomed to low nicotine, kept their nicotine intake down by some change in smoking habit. Before the crossover and this change in smoking habit the men smoking NSM cigarettes had a small but significant reduction of cough. Cigarettes containing 30% NSM and delivering only 1 mg of nicotine are likely to be acceptable to smokers and may reduce coughing. Further trials are needed to confirm these findings and establish what long-term effects such cigarettes may have on smokers' health.
Adult↗
Exercise tests before and after heart valve replacement.
A simple progressive exercise test was performed before and after operation on five subjects undergoing mitral valve replacement and on five subjects undergoing aortic valve replacement. The responses of heart rate and ventilation were related to work rate )kilopond metres/min). The patients were also assessed clinically by the New York Heart Association grading and radiologically before each exercise test. The clinical grading was shown to be a poor guide to observed exercise tolerance, as the improvement noted in symptoms was not matched by the objective measurement of working capacity. Only two patients had normal exercise tolerance after surgery, although six of the ten patients claimed that they had no exertional dyspnoea after operation. The changes in simple ventilatory function tests before and after operation were generally small. We suggest that measurements of exercise tolerance before and after operation should be an essential part of heart valve replacement surgery.
Adult↗
Asthma due to inhaled chemical agents--amprolium hydrochloride.
A man with no previous history of allergy or chest disease developed asthma after exposure to a heavy atmospheric concentration of amprolium hydrochloride which is a constituent of a poultry-food additive. Subsequent experimental exposure produced an immediate asthmatic reaction which was inhibited by sodium cromoglycate.
Aged↗
Changes in lung mechanics during asthma induced by exercise.
Pulmonary and airway mechanics were assessed in seven asthmatic patients in remission, when asthma was induced by exercise and again after spontaneous recovery or bronchodilator treatment. After exercise there was a sustained fall in forced expiratory volume in 1 s (FEV 1.0) in all patients, varying from 30 to 80 percent of the initial value. Total lung capacity (TLC) increased significantly in four of the seven patients. In one of the four patients the increase in TLC was associated with an increase in static transpulmonary pressure at full inflation but in the remaining three patients it was associated with a parallel shift of the pressure-volume curve of the lung without change in its slope. In all patients residual volume increased, regardless of change in TLC; both pressure-volume and maximum expiratory flow-volume curves suggested that widespread airway closure (or virtual closure) occurred at positive transpulmonary pressures when asthma was induced. Loss of lung recoli pressure sometimes contributed to the reduction in maximum expiratory flow but diffuse airway narrowing was probably the dominant abnormality. When air-flow obstruction became more severe the ratio of expiratory to inspiratory time was increased and although expiratory flow limitation was present excessive expiratory pressures were not generated.
Adolescent↗
A comparison of transparent adherent and dry sterile gauze dressings for long-term central catheters in patients undergoing bone marrow transplant.
Patients undergoing bone marrow transplant (BMT) are at great risk of infection and sepsis. Long-term central catheters (LTCCs), required for IV therapy, can be a portal of entry for infectious agents. This randomized, prospective study compared two types of catheter dressings in 98 patients undergoing BMT: a dry sterile gauze dressing (DSGD) changed daily and a transparent adherent dressing (TAD) changed every four days. Study outcomes included incidence and severity of local and systemic complications, patient assessment of comfort, and calculation of nursing time. One case of catheter-related infection occurred during the study. No significant differences existed between the two dressings in the incidence of positive skin cultures or local complications with the exception of skin irritation. The TAD caused less skin irritation, was preferred by patients, cost less, and required less nursing time. The findings indicate that TADs provide a safe, comfortable, and cost-effective alternative to DSGDs for patients undergoing BMT and receiving antibiotic support during aplasia.
Adolescent↗