Biomedical subjects

R Meschig

Publications and source records attributed to R Meschig.

14 recordsLinked to original sources

PubMed1991

Cytogenetic effects during extracorporeal photopheresis treatment of two patients with cutaneous T-cell lymphoma.

The effect of extracorporeal photopheresis (EP) on various cytogenetic parameters has been investigated. During EP the photoactivatable agent 8-methoxypsoralen (8-MOP) was administered orally. After 2 h a leukocyte-enriched blood fraction was collected by haemocentrifugation, irradiated with UVA extracorporeally, and reinfused to the patient. Two patients suffering from cutaneous T-cell lymphoma showed a marked clinical improvement in response to therapy. In order to investigate the cytogenetic effects and mutagenic risk of EP, the mitotic index (MI), the type and number of chromosomal aberrations and the rate of sister chromatid exchanges (SCE) were studied. Following EP treatment the patients' lymphocytes were cultured and stimulated with phytohaemagglutinin (PHA) for 48 or 72 h. The cultured lymphocytes showed a decreased MI after 48 h as an indicator of cytotoxic effects, but not after 72 h. In lymphocyte cultures not stimulated with PHA, the MI was decreased even after 72 h. The number of chromosomal aberrations and SCE were increased upon treatment, but only transiently, returning to basal levels between consecutive treatments. Our data provides no evidence for increased mutagenic risk as a consequence of effective EP treatment.

Administration, Oral↗

PubMed1989

[Moulages--wax models in dermatology].

Wax models have been used for more than 2,000 years. In the 17th century, wax moulages--besides anatomical drawings--became more and more important as three-dimensional illustrations in the training of medical students and physicians. During the 19th century, dermatological and venereological diseases, too, were imitated by colored wax models. When new procedures of pictorial representation such as photography and film were introduced, the wax models temporarily lost their instructive value. Since then, we have gradually discovered their historical significance, as well as their importance as works of art. Our article deals with the development of moulages from Roman death masks up to the modern models of medical instruction and is illustrated by quotations from reknowned moulage artists.

History, 17th Century↗

PubMed1989

[Kaposi's sarcoma after kidney transplantation].

A Kaposi's sarcoma of the skin with nodular and follicular lesions but no visceral involvement developed in a 44-year-old man nine months after transplantation of an haplo-identical kidney (a relative as donor). He was on an immunosuppressive regimen of daily 10 mg methylprednisolone and 2.5 mg/kg cyclosporin A. No HIV antibodies were demonstrated. After reduction of the dosage to 4 mg methylprednisolone and 1 mg/kg cyclosporin A no further growth of the skin lesions was observed, while transplant function was maintained. The lesions regressed after radiation of two areas in the right lower leg with 48 Gy. Ten months later the sarcoma again progressed and required further radiotherapy, which arrested growth, while there was no change in transplant function.

Adult↗

PubMed1989

[Acral lentiginous malignant melanoma].

Whether acral lentiginous malignant melanoma (ALM) has to be regarded as an independent entity of malignant melanoma is still controversial. But sure, there are some clinical and histological characteristics regarding melanoma of acral location which support a separate consideration of this disease. Our paper will discuss the peculiarities of ALM.

Aged↗

PubMed1986

No evidence for serotonergic-adrenergic interactions in the canine total cardiovascular system.

Possible in vivo interactions of serotonin and noradrenaline were investigated in 7 anesthetized mongrel dogs. The hemodynamic effects of three different doses of serotonin (10, 50 and 100 micrograms/kg/min) were analyzed with and without noradrenaline treatment (0.05-0.1 micrograms/kg/min). There were no significant differences in peripheral and cardiac responses between the pure serotonin effect and the hemodynamic effects of a parallel serotonin-noradrenaline infusion. The discussed amplifying effect of serotonin on the adrenergic system could not be observed in the total canine cardiovascular system.

Animals↗

PubMed1986

[Course of left-ventricular contraction in left bundle-branch block and its hemodynamic effects].

The aim of the study was to analyse the left ventricular contraction pattern in left bundle branch block (LBBB), to create experimentally a comparable pattern in animals and to relate this to haemodynamic measurements. In 20 normal subjects and 16 patients with LBBB without coronary heart disease we performed computer-assisted segmental left ventricular wall motion analysis during various systolic periods using two-dimensional echocardiography. The normal subjects showed on average a uniform shortening of all segments in systole; in patients with LBBB, however, asynchronous contractions of various types and intensities were found. Examination of the contraction pattern of each LBBB patient within the confidence range of the normal subjects showed that in 94% there was an abnormally small shortening of one of the sectors at one time in the second part of systole, and in 74% in the region of the interventricular septum. A "septum index" showed significant differences (p less than 0.0025) between LBBB patients and normal subjects. By right ventricular stimulation of the apex (RVA) and the outflow tract (RVOT) we simulated these contraction patterns in 6 dogs. With RVA stimulation the left ventricular contraction pattern was nearly physiological, while with RVOT stimulation the septum movement was paradoxical. With RVA stimulation cardiac output measured by thermodilution was higher (3.45 vs. 3.11 l/min, p less than 0.002) and the left ventricular end-diastolic pressure lower (7.0 vs. 8.0 mm Hg, p less than 0.002) than on RVOT stimulation; aortic pressure and the first derivative of left ventricular pressure did not differ significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1985

Serotonin-induced vasoconstriction in the perfused canine femoral artery can be blocked in vivo by ketanserin.

Serotonin, applied to helical strips of larger vessels such as coronary arteries, acts as a potent vasoconstrictor in vitro. In contrast, in vivo serotonin causes a remarkable decrease in total peripheral resistance. To differentiate the influence of serotonin on resistances of large and small vessels, experiments were done in nine anesthetized dogs. The left iliacal artery was cannulated and blood flow into the femoral artery was kept constant by a roller pump. Mean proximal femoral artery pressure and mean dorsal pedal artery pressure were measured. Pressure gradient (delta P), resistances between proximal femoral artery and dorsal pedal artery (R1), dorsal pedal artery and right atrium (R2), as well as total peripheral resistance were calculated during systemic infusion of 50 micrograms/kg X min serotonin. Serotonin caused a significant increase in delta P and R1 and a decrease in R2 and total peripheral resistance. Pretreatment with 100 micrograms/kg ketanserin abolished the significant change in delta P and R1, whereas the decrease in R2 and total peripheral resistance was not affected. Additional experiments with prazosin showed that alpha-receptors are obviously not involved in the responses observed. Isosorbide dinitrate, which was infused to differentiate passive and active narrowing of vessels, showed a serotoninlike decrease in mean dorsal pedal artery pressure but no change in either delta P or R1. The 5--HT2-serotonergic antagonist ketanserin blocked serotonin-induced constriction of large vessels in vivo but not the dilation of small arteries.

Animals↗

PubMed1985

Effects of serotonin on the cardiopulmonary circulatory system with and without 5-HT2-receptor blockade by ketanserin.

Pulmonary embolism may cause pulmonary hypertension by mechanical obstruction, which might be amplified by vasoconstriction induced by serotonin released from the emboli. The purpose of the present study was to examine whether 5-HT2-receptors are involved in serotonin-induced pulmonary hypertension. Ketanserin was used as 5-HT2-serotonergic antagonist. In nine anesthetized mongrel dogs, the effect of serotonin infusions (10, 50, 100 micrograms/kg . min) on mean pulmonary artery pressure (PAP), pulmonary vascular resistance (PVR), cardiac output (CO), stroke volume (SV), cardiac contractility (dP/dtmax), heart rate (HR), and mean aortic pressure (PAO) was studied with and without treatment by ketanserin (20 and 100 micrograms/kg). Serotonin caused dose-dependent increase in PAP, PVR, CO, SV, and dP/dtmax. A dose of 20 micrograms/kg ketanserin did not affect hemodynamics significantly, whereas 100 micrograms/kg of the compound significantly reduced PAO, TPR, and left ventricular dP/dtmax. The serotonin-induced increases in PAP, PVR, dP/dtmax, CO, and SV were reduced significantly by 100 micrograms/kg ketanserin; the lower dose of ketanserin had only a slight blocking effect. Ketanserin blocks serotonin-induced pulmonary vasoconstriction partly, but it seems also to antagonize the positive inotropic effect of the monoamine.

Animals↗

PubMed1984

Hemodynamic studies on cimetidine and ranitidine in anesthetized dogs.

The cardiovascular effects of the H2-receptor-antagonists cimetidine and ranitidine have been compared in a randomized double-blind crossover study. The experiments were performed in seven anesthetized mongrel dogs. Cimetidine (200 mg) and ranitidine (50 mg) were infused i.v. for 2 min. The time interval between cimetidine and ranitidine application was always 3 h. The direct comparison of the drug effects on blood pressure shows a significant difference between cimetidine and ranitidine (P less than 0.001). Apart from the sequence of application, cimetidine causes a significant decrease (P less than 0.01) in total peripheral resistance (-271 +/- 50 dyn . s . cm-5) resulting in a decrease in mean blood pressure (-9 +/- 1.1 mmHg). In contrast to cimetidine, none of the recorded parameters are altered significantly by ranitidine. Heart rate, left ventricular end-diastolic pressure, myocardial contractility (dP/dtmaxLV), mean right atrial pressure, mean pulmonary artery pressure, and cardiac output are not affected significantly by either drug. Due to our results it might be concluded that the cimetidine-induced hypotension is mediated by peripheral vasodilation.

Animals↗

PubMed1983