Biomedical subjects
Publications and source records attributed to F J Meyer.
We report the case of a 50 year old clerk with chronic extrinsic allergic alveolitis due to a wreath of feathers from his dead budgerigar hanging in his living-room. Diagnosis was confirmed by serum precipitins, bronchoalveolar lavage and open lung biopsy. It is important to recognize unusual sources of exposure in this disease.
Lung volume reduction surgery (LVRS) in patients with severe lung emphysema restores the thoracic configuration to a more normal functional capacity. The aim of this study was to investigate whether reduction in intrathoracic volume by LVRS improves the inspiratory muscle force generation of the respiratory pump. Pulmonary function tests, maximal inspiratory mouth pressure (MIP), sniff nasal inspiratory pressure (SNIP), sniff transdiaphragmatic pressure (Pdi), and inspiratory mouth occlusion pressure (P0.1) were measured in 17 emphysematous patients (mean (+/- SEM) age 53 +/- 2 yrs) before and 1 month after LVRS. The mean value of forced expiratory volume in one second (FEV1) increased (0.82 +/- 0.07 vs 1.12 +/- 0.08 L; p < 0.0001), whilst there was a decrease (p < 0.0001) in residual volume (RV) (337 +/- 31 vs 250 +/- 21 % of predicted), functional residual capacity (FRC) (210 +/- 9 vs 159 +/- 9% pred), and total lung capacity (TLC) (138 +/- 6 vs 110 +/- 5% pred). The mean value of MIP increased by 52% from 4.8 +/- 0.4 to 7.3 +/- 0.6 kPa (p < 0.001), the mean value of SNIP increased by 66% from 3.9 +/- 0.4 to 6.5 +/- 0.5 kPa (p < 0.001), and the mean value of Pdi increased by 28% from 6.0 +/- 0.6 to 7.7 +/- 0.8 kPa (p < 0.05) after LVRS. P0.1 decreased on average by 24% from 0.46 +/- 0.03 to 0.35 +/- 0.02 kPa after LVRS. No significant correlations were found between inspiratory muscle (MIP, SNIP, Pdi) and respiratory drive (P0.1) indices, lung function data, 6 min walk distance, or dyspnoea score. In conclusion, the observed clinical improvement of patients with severe emphysema after lung volume reduction surgery results, in part, from an increased ability of the inspiratory muscles to generate force, which is paralleled by a significant decrease in central respiratory drive.
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In this prospective study conducted by 9 Public Health Offices in North Rhine Westphalia 1992 to 1994, among the analysed 4058 asylum seekers aged 1-89 years the chest radiographs showed in 444 cases old specific changes and in 48 cases active tuberculosis. This was verified microbiologically. 81% of the evaluated tuberculin skin test were positive with variations between the different countries of origin, which is significantly higher than among persons born in the Fed. Rep. of Germany. A compulsory chest radiograph shortly after arrival and controlled curative or preventive chemotherapy programmes are urgently needed.
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An all-glass apparatus for perfusing isolated rat livers was constructed for use in studies of the metabolism by, or action on, the liver of lipophilic substrates. Other designs, which generally include plastic connections or cannulae, can have unnecessarily complicated kinetics because of adsorption of the agent to the plastic parts. Two versions of an all-glass perfusion apparatus are described in detail. Both instruments operate on the same basic principle, but differ in size, total recirculating volume, pump rate, perfusion head pressures, maximum perfusate flow rate, maximum linear velocity in the perfusion head, and oxygenation efficiency. Although the maximum protein handling capacity differs for the two apparatuses, this capacity is so limited that it disallows the use of albumin in the perfusate.
Quantitative two-dimensional echocardiography was evaluated in 39 open-chest dogs placed on cardiopulmonary bypass. The correlation coefficient of left ventricular end-diastolic volume against postmortem pressure-volume curves was r = 0.89 to 0.93 (347 measurements in 15 dogs, 0 to 24 mm Hg). Ejection fraction was validated against roller pump flow and echo left ventricular end-diastolic volume (r = 0.83, n = 13). Left ventricular mass in vivo was compared with postmortem left ventricular mass (r = 0.81 in 21 early studies, r = 0.91 in 10 later studies with updated equipment) and was found to increase with ischemic injury as well as cardiopulmonary bypass with hemodilution. Left ventricular mass increased (p less than 0.001) from 119 +/- 5 (standard error of the mean) to 138 +/- 6 gm (n = 23) after 2 1/2 hours on cardiopulmonary bypass and moderate hemodilution. With the addition of ischemic arrest, left ventricular mass increased from 119 +/- 7 to 148 +/- 11 gm (p less than 0.01, n = 8), and myocardial water content increased by 2.0% +/- 0.4%, which accounted for at least 65% of the observed mass change. Mean left ventricular wall thickness increased from 13.8 to 15.5 mm (p = 0.02) after ischemia. Ventricular shape became more spherical with increasing left ventricular end-diastolic pressure. We conclude that two-dimensional echocardiography can be reliably used for accurate, serial measurements in physiological studies. The demonstrated variability in left ventricular mass is important, yet frequently ignored. Recognizing left ventricular mass changes may facilitate the detection of myocardial injury reflected as edema.
Although the presence of entrapped air in the left ventricle at surgery has long been a concern, its prevalence and clinical significance are unknown. Two-dimensional echocardiography provides a unique means for observing intracardiac microbubbles intraoperatively. Accordingly, intraoperative 2-dimensional echocardiograms obtained in 79 patients immediately after cardiopulmonary bypass were examined for the presence of microbubbles. Left ventricular microbubbles were detected in 14% of coronary artery bypass operations (n = 22), 50% of multiple valve replacements (n = 8), 67% of single valve replacements (n = 58), and 100% of atrial septal defect closures (n = 4), left atrial myxoma resections (n = 2), and mitral commissurotomies (n = 2). Microbubbles were not observed in patients undergoing coronary artery bypass with valve replacement (n = 4) or with removal of left ventricular aneurysm (n = 1). Continuous ejection of microbubbles from the left ventricle was frequently noted for extended periods of time and, although no patient in this study showed evidence of gross neurologic dysfunction, the possibility of subclinical organ damage exists. We conclude that 2-dimensional echocardiography is useful for detection of intracardiac microbubbles and therefore may be instrumental in their elimination.
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The timed-release of anticancer agents from composities with poly (lactic acid) was studied in rats. In the case of cyclophosphamide-poly (lactic acid) composites, 67% of the administered dose was released within 34 days. With cis-dichlorodiammineplatinum (II), the amount of drug released was only 9.3% within the same period. This difference might be attributed to the different solubilities of these two drugs in the polymer. Electron spectroscopy chemical analysis, a new tool, was used to investigate the extent of diffusion of drugs in polymer films.
Parallel in vitro and in vivo release rates of tritiated naltrexone from poly(lactic acid) composites were studied. The in vitro release of naltrexone was 67% of the dose over a 35-day test period, while the in vivo release was only 24% within 70 days. Apparently, an exchange of the tritium for the hydrogen of the body water takes place, indicating that urinary excretion radioactivity is not a reliable measure for estimating the naltrexone released. Naltrexone-poly(lactic acid) composites showed effective blocking action to morphine in rats (24 days), dogs (29 days), monkeys (20 days), and mice (21 days).
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We characterized the properties of vascular dopamine receptors on isolated rabbit mesenteric arteries preincubated with phenoxybenzamine (10(-5) M) and contracted with prostaglandin F2 alpha (PGF2 alpha). The dose-response curve for dopamine-induced relaxation was shifted to the right by the dopamine receptor antagonist d-butaclamol (10(-7)--3 X 10(-6) M) in a concentration-dependent manner. The pA2 value for d-butaclamol was calculated as 6.77. In contrast, even a very high concentration (3 X 10(-6) M) of l-butaclamol had no effect, indicating that vascular dopamine receptors require stereospecificity of antagonists. In the same preparation the mechanism of relaxation by 2-amino-6,7-dihydroxy-1,2,3,4-tetrahydronaphthalene (A-6,7-DTN; 3 X 10(-7)--10(-4) M) and bromocriptine (10(-6)--3 X 10(-4) M) was found to be dopaminomimetic, since only the dopamine receptor antagonists droperidol (10(-5) M) and metoclopramide (5 X 10(-5) M) could inhibit relaxations, whereas the beta-adrenoceptor antagonists pindolol (10(-7) M) and propranolol (10(-6) M) were without effect. It is concluded that receptors specific for dopamine exist on the rabbit mesenteric artery, which may tentatively be classified as belonging to the D1-type.