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Biomedical subjects

A G Robins

Publications and source records attributed to A G Robins.

12 recordsLinked to original sources
PubMed1999

Analysis of a petrol plume over England: 18-19 January 1997.

OBJECTIVES: About 7000 tonnes of unleaded petrol were discharged into the English Channel after a tanker collision off Ostend on Saturday 18 January 1997. The petrol evaporated and the vapour plume was carried across the central part of England to Wales, resulting in reports of unidentified odours, and irritation of the eyes, skin, and upper respiratory tract. This work uses this incident to show how marine and atmospheric dispersion modelling together with routine air quality monitoring can assist in identifying hazards to the population at risk from chemical incidents. METHODS: Public health surveillance and results from environmental sampling were compared with the behaviour of the plume as predicted by computer modelling. RESULTS: The predicted plume path and dispersion were shown to correlate well with the results from surveillance and environmental analysis. CONCLUSIONS: There is a need for public health professionals to interact with medical toxicologists, atmospheric and marine scientists and engineers, and other environmental experts in managing events of this nature.

Air Movements↗
PubMed1997

Do homosexual and bisexual men who place others at potential risk for HIV have unique psychological profiles?

Prevention of HIV infection requires individuals to attend not only to their own risk but also whether they place others at risk. To design appropriate interventions, however, it is important to determine whether HIV positive and HIV negative individuals who place others at potential risk differ in their psychological profiles. Such differences would suggest the need for specially tailored interventions for each group. We studied 525 homosexual and bisexual men (156 HIV positive, 369 HIV negative) from the Multicenter AIDS Cohort Study (Pittsburgh site) to (a) identify correlates of risky behavior and (b) determine whether these correlates differed by HIV serostatus. Although HIV positive men were somewhat less likely than HIV negative men to have engaged in high-risk sexual activity in the past 6 months (e.g., unprotected insertive anal intercourse), the correlates of such activity were identical across groups. Regardless of serostatus, men placing others at potential risk were younger, less educated, had less psychological distress and greater feelings of mastery, employed fewer active behavioral coping strategies, and were heavier users of alcohol and amyl nitrate (poppers).

Adaptation, Psychological↗
PubMed1994

Psychosocial factors associated with risky sexual behavior among HIV-seropositive gay men.

The present study examines sociodemographic characteristics, levels of psychological distress, and coping styles among HIV-seropositive (HIV+) gay men who either did or did not engage in sexual activity which placed others at risk for HIV infection. Risky sexual behavior was defined as engaging in insertive anal intercourse. Respondents were 156 HIV+ men enrolled at the Pittsburgh site of the Multicenter AIDS Cohort Study in 1989-90. HIV+ men who engaged in risky sexual behavior, while similar to remaining HIV+ men on most sociodemographic characteristics, showed lower levels of psychological distress and somewhat higher feelings of control over their lives. Risky men were less likely to employ active, behavioral strategies for day-to-day coping with the issues of HIV infection and AIDS, and were more likely to report using recreational drugs to reduce tension associated with thoughts about HIV. This profile of psychosocial characteristics associated with risky sexual activity may lead to further refinement of educational and other intervention strategies with HIV+ men. Implications for such strategies are discussed.

Adult↗
PubMed1992

Impact of dyspnea and physiologic function on general health status in patients with chronic obstructive pulmonary disease.

STUDY OBJECTIVE: To examine the relationship among clinical dyspnea ratings, physiologic pulmonary function, and general health status in symptomatic patients with chronic obstructive pulmonary disease (COPD). DESIGN: Observational data collected at a baseline state. SETTING: Outpatient pulmonary disease clinics at a university hospital and two VA medical centers. PATIENTS: One hundred ten male patients with COPD with no significant comorbidity were recruited. MEASUREMENTS AND RESULTS: Clinical ratings of dyspnea were measured by the multidimensional baseline dyspnea index (BDI). Pulmonary function tests included forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and maximal inspiratory mouth pressure (PImax). General health status was assessed with the Medical Outcomes Study short-form survey, which consists of 20 questions that cover six health components. The mean age of the patients was 67 +/- 8 yr (+/- SD). The mean value for FVC was 2.84 +/- 0.84 L (68 +/- 18 percent of predicted), for FEV1 was 1.28 +/- 0.59 L (44 +/- 17 percent of predicted), and for PImax was 59.0 +/- 25.0 cm H2O. The BDI score and PImax were significantly correlated with five of the six components of general health status. Only three of the six components of general health were significantly correlated with FEV1 as percent predicted (rs value range, 0.30 to 0.44) and with FVC as percent predicted (rs value range, 0.25 to 0.33). Statistical comparisons showed that the BDI score had significantly higher correlations than FVC (percent predicted), FEV1 (percent predicted), and PImax values with physical functioning and role functioning. Multiple linear regression analysis showed that the BDI score was the only statistically significant predictor of role functioning, mental health, and health perceptions for general health status, whereas both the BDI score and FEV1 (percent predicted) were independent predictors of physical functioning and social functioning. CONCLUSION: Dyspnea ratings influence and predict general health status to a greater extent than do physiologic measurements in symptomatic patients with COPD. A shift in focus from the pathophysiology of disease to assessment and relief of symptoms may provide more meaningful benefits for the individual patient in terms of quality of life. This consideration requires that health-care providers use available measuring tools in clinical practice to quantify symptoms, as well as overall health status.

Adult↗
PubMed1986

Bronchopulmonary lavage in pulmonary alveolar proteinosis: chest radiograph observations.

Ten therapeutic bronchopulmonary lavages were performed in four patients with pulmonary alveolar proteinosis. Chest radiographs taken during the lavage procedure showed increased density of the washed lung owing to the presence of instilled lavage saline. Radiographs obtained within the first hours after lavage showed a spectrum of change from minimal improvement to marked worsening compared with prelavage examinations. Subsequent radiographs over the next week showed gradual improvement in the treated lung. By 6 weeks there was moderate to marked improvement of chest radiographs compared with baseline in all cases.

Humans↗
PubMed1983

Pathophysiology of emphysema.

The pathophysiology of emphysema is best explained on the basis of decreased pulmonary elastic recoil. At any pleural pressure, the lung volume is higher than normal. Additionally, the altered relation between pleural and alveolar pressure facilitates expiratory dynamic compression of airways. Such compression limits airflow during forced expiration and, in severe instances, during tidal expiration. Another factor contributing to airflow limitation is disease of the airways, both large and small. In general, patients with relatively pure emphysema maintain blood gases in or near the normal range until very late in their course. PaO2 is maintained because of the preserved matching of ventilation and perfusion as alveolar walls are destroyed. PaCO2 is maintained because the ventilatory response to CO2 is not usually impaired. It is not clear why patients who are categorized clinically as "chronic bronchitics" are more likely to respond to an increased flow-resistive work of breathing by hypoventilating. Physical findings in emphysema are not specific. Radiologic changes are insensitive and are of less value than physiologic measurements.

Humans↗
PubMed1982

Dynamic hyperinflation and ventilator dependence in chronic obstructive pulmonary disease.

In advanced chronic obstructive pulmonary diseases, functional residual capacity (FRC) can be markedly increased by dynamic mechanisms involving expiratory flow limitation. We studied respiratory mechanics in a seated ventilator-dependent patient with such changes. Relaxed expiration was flow-limited; pressures of 9 to 27 cm H2O (varying with lung volume) could be applied to the airway opening (Pao) without decreasing expiratory flow rate. The FRC was at least 2 L above relaxation volume. Inspiratory total resistance was 16 cm H2O/L/s. Compliance of the lung was 0.16, chest wall was 0.04, and respiratory system was 0.032 L/cm H2O. More importantly, recoil pressures at end inspiration and end expiration, respectively, were 6.5 and 1.5 cm H2O for the lung, 33 and 11 cm H2O for chest wall, and 38 and 12 cm H2O for the respiratory system. Thus the chest wall recoiled inward at all times, pleural pressure was always substantially positive (11 to 33 cm H2O), expiratory flow was maximal, and jugular veins were always full and nonpulsating. Inspiratory work was about 0.27 kg-m per breath (7 times normal), most of it elastic work done on the chest wall.

Aged↗
PubMed1981

Partial purification and characterization of a gelatin-specific protease from the culture media of human pulmonary alveolar macrophages.

A gelatin-specific protease from the culture media of human pulmonary alveolar macrophages has been partial purified by gel filtration and characterized. The macrophages were obtained by bronchopulmonary lavage from the lungs of disease-free smoking volunteers. The gelatin-specific protease initially requires trypsin activation. After chromatographing the culture media on a Sephadex G-200 column, trypsin is no longer required for activation. The gelatin-specific protease reported here shares many properties of previously reported gelatinases. It is inhibited by EDTA, cysteine, dithiothreitol and serum. It is unaffected by other protease inhibitors: phenylmethylsulfonyl fluoride, tosyllysine chloromethyl ketone and p-chloromercuribenzoate. Of all substrates tested activity was observed only with gelatin. It was inactive toward collagen, elastin and methemoglobin. This enzyme may have a role in the digestion of collagen which has been cleaved by a mammalian collagenase.

Animals↗