PubMed Health⌕ Search

Biomedical subjects

R Becker

Publications and source records attributed to R Becker.

At least 109 records · Page 6Linked to original sources
PubMed1982

Effect of induced erythrocythemia on hypoxia tolerance during physical exercise.

The effect of induced erythrocythemia on hypoxia tolerance during physical exercise was determined for five male mountain climbers. Treadmill testing was performed under four conditions: 1) prereinfusion, normoxia (Pre-N); 2) prereinfusion, hypoxia (Pre-H); 3) postreinfusion, normoxia (Post-N); and 4) postreinfusion, hypoxia (Post-H). An altitude of 3,566.2 m was simulated by having subjects breath a gas mixture of 13.5% O2-86.5% N2 at normal barometric pressure. Tests were administered immediately before and 24 h after autologous transfusion of 750 ml of red blood cells. Hematocrit increased from 43.3% at prereinfusion to 54.8% at postreinfusion. Hemoglobin concentration increased from 13.80 g X 100 ml-1 at prereinfusion to 17.63 g X 100 ml-1 at postreinfusion. Maximal O2 uptake (VO2 max, 1 X min-1) increased (P less than 0.05) by 12.8% (3.28 to 3.70) from Pre-N to Post-N and 13.0% (2.62 to 2.96) from Pre-H to Post-H. Treadmill performance time (s) increased (P less than 0.05) by 15.8% (793 to 918) from Pre-N to Post-N and 8.9% (687 to 748) from Pre-H to Post-H. VO2 max decreased by 20.1% from Pre-N to Pre-H and by 9.8% from Pre-N to Post-H. Treadmill time decreased by 13.4% from Pre-N to Pre-H and 5.7% from Pre-N to Post-H. The calculated change in hypoxia tolerance following reinfusion indicated that physiological altitude was improved by 463.6 m. It was concluded that induced erythrocythemia increased hypoxia tolerance during physical exercise.

Adult↗
PubMed1982

[The etiology, course and prognosis of dilated cardiomyopathy].

UNLABELLED: In order to study the etiology, the clinical course and the prognosis of patients with DCM, clinical, morphological (endomyocardial catheter biopsy), angiographic and hemodynamic data of patients with DCM were studied. The total number of patients was 396. In 258 patients definite DCM was diagnosed, in 138 patients DCM was suspected, e.g., because of an additional history of alcoholism. ETIOLOGY: In no case acute subacute or chronic myocarditis was found in myocardial biopsies (n = 114) and at autopsy (n = 18). However, from the history strong evidence was obtained for DCM being the late stage of diphtheric heart disease predominantly among patients with complete left bundle branch block. As far as the alcoholic etiology is concerned, the only significant difference between DCM and alcoholic heart disease was a higher proportion of women among patients with DCM (28% and 5%, resp.). Clinical course and prognosis: 221 patients were studied prospectively (mean follow-up time 3.1 +/- 2.3 years), 44% of patients died or deteriorated. However, in patients with normal cardiothoracic ratio this rate amounted only to 12%. The mean annual mortality rate was 9.8% and varied significantly in relation to different subsets of patients from 0% to 17%. A bad prognosis was significantly indicated by young age, high cardiothoracic ratio, pronounced elevation of enddiastolic volume index and of left ventricular enddiastolic pressure at rest and of mean pulmonary artery pressure at exercise, by severe morphologic changes of myocardial biopsies, severe ventricular arrhythmias, the absence of transient abnormal elevation of arterial blood pressure during follow up, of complete left bundle branch block and of a positive history of diphtheria. However, the wide scatter of data diminished the significance of them for the definite prognostic evaluation of individual case. The cumulative survival curves of patients with a history of alcohol abuse did not differ from that of patients with DCM. The data demonstrate that DCM in patients with the history of diphtheria together with left bundle branch block is possible caused by an inflammatory process. According to the analysis of the clinical course and the prognosis, DCM is one of the most severe heart disease. However, in different subsets of patients, the clinical course may be stable for long time and even normal longevity cannot be excluded.

Adult↗
PubMed1982

Influence of prostacyclin on regional blood flow distribution in anesthetized dogs.

Prostacyclin (PGI2), a major metabolite of arachidonic acid, is widely distributed throughout the cardiovascular system and may influence vascular smooth muscle tone. To evaluate the effects of PGI2 on regional blood flow distribution in anesthetized dogs, the tracer microsphere reference sample method was used. Intravenous PGI2 infusions (0.5 and 1.0 microgram/kg/min) increased renal, adrenal, splenic, small intestinal, brain and pituitary blood flow, whereas pancreatic, fundic and skeletal muscle perfusion were diminished by PGI2. Hepatic and myocardial blood flow remained unchanged. This study demonstrates striking differences in regional vascular sensitivity to PGI2, which should be kept in mind when evaluating the potential therapeutic usefulness of PGI2 in a variety of clinical situations.

Anesthesia↗
PubMed1982

The metabolic fate of supidimide in the rat.

The absorption, metabolism and excretion of 3-(2,3-dihydro-1,1-dioxido-3-oxo-1,2-benzisothiazol-2-yl)-2-oxopiperidine (supidimide) in the rat are investigated. Following oral administration of 35S-labelled supidimide (12.5 and 25 mg/kg), the radioactivity is rapidly absorbed and excreted almost quantitatively within 72 h. 85% of the radioactivity administered is recovered from urine. In the faeces a further 14% is found predominantly resulting from biliary excretion. Excretion rates of urinary radioactivity show a 2-phase course with half-lives of 2.6 h and 10 h. Unchanged supidimide is eliminated with a half-life of 2.1 h. A total of 10 metabolites are identified in urine, faeces or in vitro systems and quantified. Identification of the metabolites is achieved by co-crystallization or co-chromatography with synthetic reference compounds, chemical analysis, mass spectrometry or combinations of these techniques. The pattern of metabolites observed in vivo and in vitro studies reveal that supidimide is primarily oxidized in the piperidone moiety of the molecule by the microsomal drug metabolizing system. Largely spontaneous hydrolysis of preexisting or newly formed carbonamide bonds gives rise to the variety of metabolic products. Hydrolysis of the sulfonamide bond and oxidation of the benzene moiety are not detectable. Only after subchronic treatment with an elevated dosage of supidimide (greater than or equal to 150 mg/kg) is a reversible induction of cytochrome P-450 observed.

Animals↗
PubMed1981

[Non-invasive recording of late ventricular potentials--methodology and first clinical experiences (author's transl)].

Late potentials occurring after the QRS complex were searched for from the body surface using high-gain amplification and signal-averaging techniques with filter settings between 100 and 300 hz at a sampling rate of 10 khz. The number of repetitions of the averaging process ranged between 150 and 300. 52 patients were studied. In 11 control subjects, no late potentials were detected within the ST segment. Late potentials were observed in 3/27 patients without previously documented ventricular tachycardia, all having left ventricular aneurysms. All three patients had evidence of increased ventricular vulnerability (one dying from ventricular tachycardia, one with stimulus-inducible ventricular tachycardia, one with multiple episodes of ventricular fibrillation after surgery). In patients with previously documented ventricular tachycardia and/or fibrillation, late potentials occurred in 7/14 cases (50%), mainly in those with aneurysms (6/8 pts = 75%). Mean onset of late potentials after the QRS complex was 38 +/- 20.1 ms, mean amplitude was 3.9 +/- 2.0 uV, and mean duration was 17.1 +/- 5.4 ms. We conclude that late potentials, which represent late depolarization of a mass of ventricular tissue after slow conduction, herald increased susceptibility to ventricular tachycardia mainly in patients with ventricular aneurysms.

Adult↗
PubMed1981

[Morphological and stereological examinations of placenta of patient with unruptured tubal pregnancy at full term (author's transl)].

Optimum conditions for foetal life were recorded from morphological and stereological findings obtained from a patient at full-term tubal pregnancy. Basiotrophic implantation, no reduction of chorion frondosum, large placental exchange surface, and extremely good capillarisation of chorionic villi proved to be the conditions for survival of the child.

Female↗
PubMed1980

The demonstration of vegetations by echocardiography in bacterial endocarditis. An indication for early surgical intervention.

The visualization of vegetations by M-mode echocardiography in patients with infective endocarditis has been suggested to imply a poor prognosis regarding the development of major systemic emboli, congestive heart failure and the need for early surgical intervention. The question of using the finding of vegetations by echocardiography as an indication for surgery is controversial. To answer this question, 30 patients with the clinical diagnosis of endocarditis were studied by echocardiography. In 17 of the 30 (57 per cent) vegetations were present (aortic eight, mitral four, both mitral and aortic five), whereas in 13 (43 per cent) no vegetations were visualized. Infecting organisms were similar in each group; Streptococcus viridans being the most common. The patients with echocardiographically demonstrable vegetations had a higher incidence of congestive heart failure compared to the patients without (14 of 17 versus six of 13, p less than 0.05), major emboli (eight of 17 versus two of 13, p = NS) and need for valve surgery (17 of 17 versus two of 13, p less than 0.001). Mortality was not significantly different in the two groups (six of 17 versus three of 13, p = NS). Urgent or emergency surgery was required in 16 of 17 patients with vegetations. Thus, the demonstration of vegetations by echocardiography identified a subset of patients with more severe disease in whom early operative intervention was required.

Adult↗
PubMed1980

Echocardiographic and surgical correlations in bacterial endocarditis.

The results of preoperative echocardiography were compared with the pathologic findings at the time of surgery in 24 patients undergoing valve surgery for endocarditis. Of the 32 valves involved by vegetations, 27 (84%) were identified preoperatively. Valve destruction was correctly predicted in 16 of 18 cases. Myocardial abscess formation was detected in only one of the five patients in whom it occurred. Overall, the echocardiograms satisfactorily predicted the pathologic anatomy in 20 cases. In the remaining four patients, the echocardiographic description was seriously incomplete or misleading. Thus, surgery can be recommended on the basis of the clinical and echocardiograhic findings for patients with endocarditis. Cardiac catheterization is reserved for patients in whom significant coronary artery disease or intracardiac shunts are suspected or in whom a satisfactory echocardiogram cannot be obtained.

Adult↗
PubMed1979

[Biological availability of Ossin, a sodium-fluoride dragee for osteoporosis therapy].

The bioavailability of Ossin, a drug for the treatment of osteoporosis, containing 40 mg of NaF, was investigated. Because of the enteric coating of the tablet, intestinal absorption occurs when the tablet leaves the stomach. The sustained release of the F--in the intestine results in a slow F-- -absorption. Maximal F-- -serum concentrations are reached more than 4 hours after absorption has begun. In contrast to non-sustained release NaF tablets the slow absorption of Ossin leads to lower, and less variable F-- -serum concentrations. Following administration of 1 tablet Ossii b.i.d., the steady state concentrations were between 130 and 220 ng/ml. The absorption was at least 86%. As calculated by the renal F-- -elimination, the therapeutically important F-- -retention in bone amounted to more than 50%. The enteric coating of the Ossin tablets, the low and relatively steady F-- -serum concentrations and the high F-- -retention in bone, are expected to contribute to an improvement in tolerance and therapeutic efficacy in the treatment of osteoporosis.

Biological Availability↗