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Biomedical subjects

T Weiss

Publications and source records attributed to T Weiss.

At least 109 records · Page 6Linked to original sources
PubMed1991

[Effect of intra-arterial and intravenous PGE1 infusions on transcutaneous oxygen pressure in patients with critical ischemia of the extremities].

In a randomized cross-over study 20 patients with peripheral arterial occlusive disease stage IV according to Fontaine received one i.a. infusion of 10 micrograms PGE1 in 25 ml saline over 30 min and one i.v. infusion of 40 micrograms PGE1 in 125 ml saline over 60 min. Transcutaneous PO2 was measured continuously (44 degrees C) on the forefoot and dorsum of the foot of the affected leg as well as on the forefoot of the contralateral limb. During i.a. infusion tcPO2 decreased by 73% on the forefoot combined with pain in the infused leg in 8 patients, whereas i.v. infusion induced a 83.1% increase in tcPO2. All in all i.v. PGE1 infusion resulted in a more pronounced increase of tcPO2 without causing side effects.

Alprostadil↗
PubMed1990

The effect of submandibular gland removal on testicular and epididymal parameters.

The effect of sialoadenectomy (submandibular gland removal) for four weeks duration was studied in five C3H mice and four sham-operated controls. This preliminary experiment using small numbers of animals indicated that sperm production parameters were lowered in sialoadenectomized animals although there were no significant differences between the sialodenectomized and sham-operated group. In a second experiment using larger numbers of animals, significant differences in testicular weights, epididymal weights, and testis weights were noted. These parameters were reduced only 10-14% from control levels. Epididymal sperm head counts were reduced 10% after sialoadenectomy but the two groups were not significantly different (P less than 0.05). No difference in testicular histology was observed. The present report contrasts to that of Tsutsumi et al. (1986) who indicate that submandibular removal with subsequent depletion of epidermal growth factor (EGF), is extremely deleterious (40-55% decreases in spermatid and sperm content) to the progress spermatogenesis.

Animals↗
PubMed1990

Dynamics of central nervous activation during motor imagination.

Central nervous processes of sensorimotor and behaviour control are prerequisites of skills and motor performance. Eight students (Ss) in sports were tested during motor imagination. They were requested to imagine their own movements when swimming over a distance of 100 m (sitting in a resting position, without any real or imitated movements). Electroencephalograms (EEG), heart rate (HR), skin conductance (SC), and respiration rate (RR) were recorded before, during and after one series of 3 periods of mental training (MT). HR, RR and SC increased during MT. The highest level of SC can be found at the beginning of the first period of imagination. Mean alpha-frequency of the EEG over the left occipital and precentral area in all Ss was higher during MT. The degree of these changes varied during the 3 imagination periods.

Brain↗
PubMed1990

Separation of left and right skull bones from low angle x-ray projections.

This study shows how two layers which are superposed in two low angle x-ray projections can be reconstructed separately without having any a priori knowledge of their shape. Similar to stereoscopic imaging, the projections of the two layers appear at different positions in the two superposition images. Matching one of the layers allows its elimination by subtraction. The resulting difference signal is the so-called 'movement artefact' of the second, mismatched layer. A filter method is developed to reconstruct this layer from the spectrum of its artefact within the Fourier domain. The second layer is reconstructed in an analogous way. So, for example, the bones of the left and the right side of the human skull can be imaged separately. This is used to reduce image artefacts caused by patient movements in subtraction angiography and tumourfluoroscopy of the brain.

Humans↗
PubMed1990

Activation and decreased deformability of neutrophils after intermittent claudication.

This study investigated local alterations in neutrophil activation and deformability after intermittent claudication. In 17 patients with one-sided peripheral arterial occlusive disease, neutrophil count, proportion of activated neutrophils (by nitro blue tetrazolium test), and neutrophil filterability as a measure of passive deformability were assessed in the femoral arterial and venous blood of the diseased leg and in the femoral venous blood of the healthy leg (n = 10). The values were obtained at rest, immediately after claudication, and 10 minutes after claudication induced by repetitive toe stands. Immediately after exercise, the arterial and venous blood differences in the diseased leg were 1) neutrophil count, 9% (95% confidence interval [CI], 5-14%; relative increase in the venous blood compared with arterial blood); 2) the proportion of activated neutrophils, 26% (CI, 10-42%); and 3) the neutrophil filterability, -10% (CI, -4% to -15%). At rest and 10 minutes after exercise, neutrophil parameters did not differ significantly between the femoral arterial and venous blood. Furthermore, no arterial and venous blood differences in the neutrophil parameters were found in the healthy leg. In addition to local changes, systemic changes occurred immediately after exercise. In the femoral arterial blood, the total neutrophil count had risen by 13% (CI, 8-18%), the proportion of activated neutrophils had risen by 41% (CI, 25-58%), and average neutrophil rigidity had risen 17% (CI, 11-22%) compared with the values obtained before exercise. At 10 minutes after exercise, all neutrophil parameters were still elevated. We conclude that even short periods of ischemia, as in intermittent claudication, cause local alterations in neutrophil function and distribution.

Arteries↗
PubMed1989

[Malignant chest wall infiltration in MR: comparison with CT and surgical findings].

CT and MRI were performed on 19 patients with pleura related thoracic tumors with respect to the detection of chest-wall invasion. All patients underwent surgery, which confirmed malignant infiltration in 16 cases, while this was excluded in three. CT showed chest-wall invasion in 12/19 patients. MRI demonstrated tumorous involvement in 16 patients. A reliable pattern of chest-wall invasion in MRI were high signal intensity lesions within the chest-wall in the T2-weighted images. However, increased signal intensity of pleural structures was found in inflammatory as well as in malignant lesions. MRI can prove the presence of chest-wall invasion when CT is equivocal.

Adult↗
PubMed1989

Cotinine levels in follicular fluid and serum of IVF patients: effect on granulosa-luteal cell function in vitro.

Cigarette smoking is accepted as a risk factor for pregnancy but its effect on fertility is uncertain. In this study we determined the concentration of cotinine, a nicotine metabolite, in follicular fluid and serum from women participating in an in-vitro fertilization and embryo transfer (IVF-ET) programme. Cotinine was undetectable in serum and follicular fluid of non-smokers but ranged from less than 5 to 371 ng/ml in follicular fluid and from 24 to 245 ng/ml in serum of smokers. Granulosa-luteal cells, obtained from IVF patients and cultured for 4 days, secreted progesterone and, when an aromatizable androgen was added, oestradiol-17 beta. The addition of cotinine or nicotine did not alter progesterone or oestradiol-17 beta secretion. However, the presence of cotinine in follicular fluid of women smokers provides evidence for access of at least one component of cigarette smoke to the developing gamete and the cells of the follicle. Further work is required to determine whether fertility is compromised by the presence, in follicular fluid, of contaminants derived from cigarette smoke.

Cells, Cultured↗
PubMed1989

Effects of beta-adrenergic activity on T-wave amplitude.

This study addresses the hypothesis that electrocardiographic T-wave amplitude is influenced by beta-adrenergic stimulation of the heart. Beta-adrenergic activity was manipulated both pharmacologically and through behavioral challenge. Under resting conditions, 12 healthy men underwent infusion of placebo and then the beta-agonist, isoproterenol, and the beta-blocker, propranolol, in a counterbalanced, crossover design. During infusion of placebo, subjects also underwent two behavioral challenges, a structured interview and mental arithmetic. Analysis of the resting data indicated that propranolol produced a significant increase in T-wave amplitude, and isoproterenol produced significant T-wave amplitude attenuation. As previously reported, drug effects were also in evidence for heart rate. Behaviorally-induced reduction of T-wave amplitude was observed for mental arithmetic but not structured interview, which again paralleled heart rate data. Both pharmacological and behavioral data reported in this study support the hypothesis that the T-wave is significantly affected by beta-sympathetic influence on the heart. However, a nonspecific effect of heart rate change on T-wave amplitude would also account for these results. The findings are discussed in terms of their implications for the utility of T-wave amplitude in psychophysiological research.

Adult↗
PubMed1989

[Possibilities of objective assessment of the course of activation in ideomotor training].

An active exploration of movement tasks is accompanied with central nervous activation. Its systematical examination needs a teamwork of scientists of various branches of knowledge (i.e. physiology, psychology, sport sciences). Mental training (motor imagination - MI) was chosen as a model for such examinations. In connection with the execution of MI there are characteristic chances of the mean alpha frequency of the EEG, heart rate, respiration rate and skin conductance. The time course of these parameters depends on the number, the duration and the sequence of MI. A graduated submaximal load on ergometer has no influence on the course of the examined parameters. Our investigation allows the conclusion that different activation processes go on within different subsystems during the execution of MI. From a physiological point of view it seems to be necessary that a concrete paradigm of MI must be examined concerning the course of the parameters and, thus, to guarantee the effort of MI.

Adolescent↗
PubMed1989

[MRI of bronchogenic carcinoma].

47 patients with histologic/cytologic confirmed bronchogenic carcinoma were examined with CT and MRI. Negative and contrast enhanced CT examinations were performed, MR images were obtained with ECG gated T1- and T2-weighted SE sequences in axial and coronal planes. Both methods were evaluated with respect to tumor imaging and delineating of tumor extensions. CT and MRI were generally in agreement for primary tumor and lymph node staging. 7 out of 10 patients with malignant pericardial involvement and 3 out of 27 patients with mediastinal subcarinal lymph node metastases were identified only in MR images. MRI was superior to CT in demonstration of aortic involvement, poststenotic syndrome and extension of chest wall invasion. Additionally MRI gave functional informations about blood flow in case of superior vena cava obstruction.

Aged↗
PubMed1989

[Clinical and computed tomographic follow-up of conservatively treated disk prolapse].

Of a total of 238 patients suffering from root compression syndrome, 41 successfully conservatively treated patients were followed up both clinically and via CT. At follow-up time they were all largely free from complaints. 71% showed unchanged prolapse on CT examination. 29% had a moderate or marked regression of disk prolapse. All unchanged cases of prolapse were medial prolapses. The reason for regression of the sequestered disk tissue is discussed controversially and has not been satisfactorily clarified to date. Improvement of findings in unchanged prolapse is mainly explained by the adaptability of the root if there is enough space for shifting.

Adult↗
PubMed1989

[MRT of intrathoracic space-occupying lesions--conventional and new rapid study technics].

100 patients with histologically and cytologically confirmed intrathoracic space-occupying growths were examined by CT and MR over and above conventional x-ray film diagnosis. MR tomography was performed in all the 100 patients via ECG-triggered T1 and T2 weighted spin echo sequences. The last 35 patients were additionally examined via gradient echo sequences with which it is possible to examined 24 consecutive layers in any layer plane within 7 minutes without ECG triggering. Comparative evaluation of CT and MR tomography yielded an equally high degree of sensitivity when identifying intrathoracic growths. Compared to CT, determination of tumour status via MR tomography proved easier in individual cases. Other advantages of MR tomography were seen in the staging of bronchial carcinomas. Compared with conventional spin echo sequences the rapid gradient echo sequences reduced examination periods by more than 50%. In the cardiac region and the mediastinal structures that pulsate with it the diagnostic value of the gradient echo images is at present slightly impaired by fuzziness caused by movement. The image quality of the spin echo images is comparatively good in the regions of the superior and posterior mediastinum, the lungs and the thoracic wall.

Carcinoma, Bronchogenic↗