Search PubMed⌕ Search

Biomedical subjects

J Appel

Publications and source records attributed to J Appel.

68 records · Page 4Linked to original sources
PubMed1977

Assessment of cardiac function in marathon runners by graphic noninvasive techniques.

The volume overload type of heart often observed in endurance athletes, was simulate a diseased heart. We used a battery of noninvasive graphic techniques, i.e., echocardiogram, apexcardiogram, carotid pulse, electrocardiogram, vectorcardiogram, phonocardiogram, systolic time intervals, and treadmill stress testing in 12 professional marathon runners, mean age 33.8 +/- 11.1. Twenty nonathletes matched for age, height, sex, and weight served as a control group. Left ventricular (LV) end-diastolic dimension in marathon runners averaged 5.53 +/- 0.5 cm compared to 4.81 +/- 0.04 cm in nonathletes (p less than 0.001), LV end-diastolic volume was 172.69 +/- 43.3 ml compared to 113.57 +/- 30.41 ml in nonathletes (p less than 0.001), stroke volume was 122.27 +/- 32.8 ml compared to 78.42 +/- 20.44 ml in non-athletes (p less than 0.001), the thickness of the posterior LV wall was 1.0 +/- 0.2 cm compared to 0.7 +/- 0.1 cm in nonathletes (p less than 0.001), and LV mass was significantly increased, 212.43 +/- 55.8 g compared to 123.48 +/- 24.54 g in non-athletes (p less than 0.01). Left atrium and aortic root were also relatively larger in athletes (p less than 0.01). Right ventricular end-diastolic dimension was enlarged in marathon runners (2.02 +/- 0.65 cm). No statistically significant differences were noted in ejection fraction, percentage of internal diameter shortening (% delta D) and PEP/LVET. The carotid tracing had a bisferiens pulse in five marathon runners. The apexcardiogram showed a bifid systolic thrust in three and absence of abnormal A wave. These abnormalities were related to the overload type of heart as proven by echocardiogram. "Early repolarization syndrome" (abnormal RS-T segment elevation) and notched T waves in ECG had a counterpart a semilunar configuration in the VCG. Three athletes met ECG criteria and one met VCG criteria of LVH. The treadmill exercise ECG was negative in all 12 athletes. Biventricular enlargement and increased left ventricular mass are present in the marathon runner's heart. Myocardial contractility at rest was, however, not statistically different from nonathletes.

Adult↗
PubMed1977

[Electron microscopic of mucopolysaccharides in the goblet cells of the bronchial mucosa].

Author using various methods of fixation and electronmicroscopical histochemistry investigated the detectability of mucopolysaccharides in the goblet cells of the bronchial mucosa obtained by biopsy. Results show, that the method of choice of the detection of glycosaminoglycans in the goblet cells is the PA-Silver technique carried out after fixation with solution of glutaraldehyde only. This technique-- when appropriate control is used--seems to be specific.

Biopsy↗
PubMedDate not supplied

The bidirectional hydrogenase of Synechocystis sp. PCC 6803 works as an electron valve during photosynthesis.

The activity of the bidirectional hydrogenase of the cyanobacterium Synechocystis sp. PCC 6803 was found not to be regulated in parallel to respiration but to photosynthesis. A mutant with a deletion in the large hydrogenase subunit gene (hoxH), which contains the active site, was impaired in the oxidation of photosystem I (PSI) when illuminated with light, which excites either PSI alone or both photosystems. The fluorescence of photosystem II (PSII) of this mutant was higher than that of wild-type cells. The transcript level of the photosynthetic genes psbA, psaA and petB was found to be different in the hydrogenase-free mutant cells compared to wild-type cells, which indicates that the hydrogenase has an effect on the regulation of these genes. Collectively, these results suggest that the bidirectional hydrogenase functions as a valve for low-potential electrons generated during the light reaction of photosynthesis, thus preventing a slowing down of electron transport. This conclusion is supported by growth curves demonstrating that the mutant cells need more time to adapt to changing light intensities. Investigations of the wild-type and deltahoxH strains strongly suggest that Synechocystis contains only the bidirectional hydrogenase, which seems to be essentially insensitive to oxygen.

Blotting, Northern↗
PubMedDate not supplied

A detailed numerical study of the evolution of soot particle size distributions in laminar premixed flames.

In this work, two numerical techniques, viz. the method of moments and a discrete h-p-Galerkin method, have been applied for numerical simulation of soot formation in a laminar premixed acetylene/oxygen/argon flame. From the evolution of the PAH and the soot particle size distributions, new insight into the different processes of soot formation is provided. For this, the single submodels have been examined with respect to their influence on the PAH and the soot particle size distributions. The particle inception step was studied in detail by comparing the simulated PAH size distributions with experimental results. Additionally, an estimation of the interaction energy of layered PAH dimers was performed by quantum chemical calculations. From these results, some evidence for the particle inception model employing coalescence of PAH molecules has been found. The numerical results for the gas phase chemical species, the particle number densities and volume fractions of soot as well as for the soot particle size distributions are compared with experimental data. Thereby, the consistency of the entire model is demonstrated.

Journal Article↗