Search PubMed⌕ Search

Biomedical subjects

R Dietz

Publications and source records attributed to R Dietz.

At least 289 records · Page 16Linked to original sources
PubMed1981

Plasma catecholamines, noradrenaline metabolism and vascular response in desoxycorticosterone acetate hypertension of rats.

Mineralocorticoid hypertension was induced in male Wistar rats by the injection of desoxycorticosterone acetate (DOCA) in oily solution (2 X 5 mg/kg daily for 7 days) and of desoxycorticosterone trimethylacetate in a microcrystalline suspension (15 mg/kg every third day for 4 weeks). A 1% NaCl solution or demineralized water was given as drinking fluid. Four weeks after the beginning of treatment, mean arterial blood pressure was 161 +/- 3.8 mmHg in DOCA-saline treated and 140 +/- 5.9 mmHg in DOCA-water-treated rats. Basal plasma levels of noradrenaline and adrenaline did not differ in conscious, unrestrained DOCA-treated rats and in control rats 3, 7 and 28 days after the beginning of hormone administration. Furosemide (50 mg/kg) caused within 30 min the same degree of diuresis and natriuresis in DOCA-treated and in control rats, but the plasma noradrenaline concentration in DOCA-treated rats rose to a higher level than in the controls. The isolated perfused hearts of rats which received DOCA for 7 and 28 days, respectively, had a reduced uptake of [3H]noradrenaline as compared to the controls. In isolated perfused hindlimb preparations from rats which had received DOCA for 7 days, the dose-response curve to noradrenaline but not that to KCl was shifted to the left. However, when DOCA and saline were given for 28 days, besides a higher sensitivity to noradrenaline an increased maximum response was observed with both noradrenaline and KCl. It is concluded that adrenergic tone is enhanced during the development of DOCA hypertension. Since the changes in the sympathetic nervous system in DOCA-water-treated rats, which had a less pronounced hypertension, were similar to those in DOCA-NaCl-treated rats, alterations in adrenergic vascular tone were not directly related to the level of the blood pressure.

Animals↗
PubMed1981

Central blood pressure effects of substance P and angiotensin II: role of the sympathetic nervous system and vasopressin.

The role of the sympathetic nervous system and of arginine vasopressin (AVP) in the mediation of the central cardiovascular effects of angiotensin II (ANG II) and substance P (SP) was investigated. ANG II and SP caused dose-dependent blood pressure increases when injected into the lateral brain ventricle (i.c.v.) of conscious rats; ANG II was tenfold more potent than SP. Peripheral blockade of alpha-adrenoceptors with prazosin or blockade of the vasopressor action of AVP by the AVP antagonist d(CH2)5VDAVP both partially inhibited the pressor responses to central ANG II. Combined treatment with the two blockers produced almost complete inhibition of the central ANG I responses. Substance P injected i.c.v. produced increases in noradrenaline and adrenaline but not AVP in the plasma. Peripheral alpha-receptor blockade by prazosin reversed the central pressor effects of SP to depressor responses. The AVP antagonist did not alter the cardiovascular responses to SP. It is concluded that in conscious animals, stimulation of the sympathetic nervous system and release of AVP contribute to the central pressor action of ANG II to a similar extent and independently of each other. In contrast, the central pressor responses to SP appear to be exclusively mediated by the sympathetic nervous system without participation of AVP.

Angiotensin II↗
PubMed1981

Malignant gliomas - glioblastoma multiforme and astrocytoma III-IV with extracranial metastases. Report of two cases.

The authors describe two rate cases of extraneural metastases of glioblastoma multiforme and of astrocytoma III-IV, but with different distribution routes. In the first case - astrocytoma III-IV - via the lymphatic system, with metastases in the cervical lymph nodes; in the second case-glioblastoma-via the blood system, with metastases in the sternum and vertebrae. Survival times were 18 months in the astrocytoma case (operation plus irradiation), and 6 months in the glioblastoma case (operation, irradiation, and chemotherapy). The discussion deals with the possible paths of the metastases, the connection between metastatic spread and survival time (in the longer surviving patient the metastases were discovered together with the recurrence), and problems in deciding the individual therapy.

Adult↗
PubMed1981

Partial replacement of sodium by potassium in the diet restores impaired noradrenaline inactivation and lowers blood pressure in stroke-prone spontaneously hypertensive rats.

1. Partial replacement of sodium by potassium in the diet attenuates the rise in blood pressure in stroke-prone spontaneously hypertensive rats (SHR-SP). 2. The blood pressure-lowering effect of potassium cannot be ascribed to a reduction in intravascular volume. 3. The increased dietary intake of potassium leads to a reduced stimulation of the sympathoneuronal and sympathoadrenal system by cold compared with the response of sodium-loaded rats. 4. The impaired inactivation of noradrenaline observed in sodium-loaded SHR-SP is improved in SHR-SP on a potassium-substituted diet. 5. It is concluded that changes in dietary intake of sodium and potassium modulate sympathetic activity and the metabolism of noradrenaline, both of which are related to the development of hypertension in SHR-SP.

Animals↗
PubMed1981

[Combined cytostatic-radiologic therapy of advanced malignant tumors in otorhinolaryngology. Experiences and results with over 100 patients].

For over ten years the therapy schedule of combined treatment (partial synchronisation) has been clinically tested and applied. Positive results are reported. The reasons for these positive results seem to be more the additive effects than the synchronisation. Despite some doubts concerning the effectivity of synchronisation, these so called partial synchronisation therapy has been applied since 1972 because of the encouraging own results and the positive results reported by other authors. 5 FU, Vincristine, Bleomycin and Adriamycin have been used as cytostatic drugs; the highly differentiated keratinizing squamous cell carcinomas should be treated with Bleomycin. Our report covers the results of over 100 patients with malignant ENT-tumors treated by the schedules. Most patients came with advanced inoperable tumors or recurrences after surgery and/or irradiation; the combined therapy with 5 FU Bleomycin and Adriamycin increased complications and side effects than radiotherapy alone. A recent trend is to use Bleomycin or Adriamycin as cytostatic drugs. The breakdown of survival rates according to the tumor localisation shows the best 5 year survival times of patients with laryngeal/hypopharyngeal carcinomas (advanced tumors respectively recurrences). This combined therapy leading to a surprising remission in a short time and to a prolongation of life with supportable feelings, seems to be an usefull supplement of therapeutical methods in advanced ENT-tumors.

Antineoplastic Agents↗
PubMed1980

Reversal of corticosterone-induced supersensitivity of vascular smooth muscle to noradrenaline by arachidonic acid and prostacyclin.

In the isolated perfused hindlimb preparation of rats treated with corticosterone (2 x 20 mg/kg daily for 2 days), the dose-response curve to noradrenaline was shifted to the left, indicating supersensitivity of the vascular bed to noradrenaline. Perfusion with arachidonic acid (10(-5) M) and prostacyclin (10(-9) M) for 5 min reversed the supersensitivity induced by corticosterone. The metabolite of prostacyclin, 6-keto PGF1 alpha(10(-9) M), was ineffective in this respect. In rats which had received desoxycorticosterone acetate (2 x 5 mg/kg daily for 7 days), there was supersensitivity of the hindlimb preparation to noradrenaline similar to that in corticosterone-treated rats. In that case, however, administration of arachidonic acid did not reverse the leftward shift of the dose-response curve. Administration of indomethacin (2 x 2.5 mg/kg for 7 days) prior to the perfusion experiment also resulted in a shift of the noradrenaline dose-response curve to the left, which was less pronounced than the shift induced by corticosterone. Combined administration of corticosterone and indomethacin caused the same increase in noradrenaline sensitivity as did corticosterone alone. Since glucocorticoids inhibit the release of arachidonic acid from phospholipids, it is concluded that corticosterone may enhance the sensitivity to noradrenaline by affecting the biosynthesis of prostaglandins.

Animals↗
PubMed1980

Vasoconstriction and increased blood pressure in the development of accelerated vascular disease.

The pathogenesis of acute vascular lesions has been studied in two types of accelerated vascular disease. Firstly, vascular lesions were induced by a short-term (2 h) infusion of angiotensin II. Low doses of angiotensin II caused only a slight increase in blood pressure and non-destructive lesions. High doses caused a significant elevation of blood pressure and destructive vascular lesions. Secondly, in renovascular hypertension, renal vascular disease was induced by the removal of the stenosing clip from the renal artery. Incidence and severity of destructive vascular lesions were correlated with the calculated gradient between the pressure before and beyond the stenosis. Anaesthesia had a protective effect on the development of destructive vascular lesions in both models. Obviously, this effect is not related to a reduction of the systemic pressure, but rather to the suppression of abnormal vascular tone, characterized by focal constriction alternating with overdilation. Vasomotor changes, which cause a local overdilation, may be responsible for destructive vascular lesions even at normal to subnormal blood-pressure values. Destructive vascular lesions occur as a result of the exceeding of a critical wall tension. The necrosis of medial smooth-muscle cells in non-destructive lesions may be explained by an excessive contraction, which "surpasses" the metabolic capacity of the cells.

Anesthesia↗
PubMed1980

Enhanced sympathetic activity caused by salt loading in spontaneously hypertensive rats.

1. Salt loading accelerates and increases the rise in blood pressure (spSH) in stroke-prone spontaneously hypertensive rats, but not in Wistar-Kyoto (WK) rats. 2. In both strains a slight increase in plasma volume was obtained during salt loading. 3. Salt loading caused a distinct increase in plasma noradrenaline concentration in spSH rats, but a slight decrease in WK rats. Plasma adrenaline and dopamine concentrations remained unaffected. 4. Exposure to cold resulted in a more marked stimulation of sympathoadrenal and sympathoneuronal activity in salt-loaded spSH rats than in spSH rats on a normal sodium diet. 5. It is concluded that salt loading results in a further increase of the already elevated sympathetic activity in spSH rats.

Aging↗
PubMed1980

Plasma catecholamine levels and vascular response in deoxycorticosterone acetate hypertension of rats.

1. In rats with deoxycorticosterone acetate (DOCA) hypertension basal plasma concentrations of noradrenaline and adrenaline correspond to those of sham-treated controls. 2. In DOCA-treated rats frusemide caused a more pronounced increase in plasma noradrenaline than in control rats. This difference was not observed for adrenaline. 3. In the isolated perfused hind-limb preparation the sensitivity to noradrenaline was already enhanced before blood pressure was elevated. 4. These results suggest that the adrenergic vascular tone is increased in DOCA hypertension in rats.

Animals↗
PubMed1980

[Diagnosis and treatment of rare tumors in the laryngeal-pharyngeal area (author's transl)].

From 1968 to 1979, 11 patients with rare tumors in the laryngeal-pharyngeal area have been treated by the Department of otolaryngology at the University hospital Homburg-Saar. These 11 cases consist of 6 benign and 5 malignant tumors. The malignant tumors were irradiated postoperatively by the Department of Radiology. There was found in the pharyngeal area 1 malignant despeciated leiomyoma, 2 malignant synovialomas and in the laryngeal area 4 local nongeneralised amyloidosis, 1 hamartoma, 1 chemodectoma, 1 pleomorphic rhabdomyosarcoma of the larynx and 1 primary "oat-cell" carcinoma. The initial exploratory excisions often led to an incorrect diagnosis: The final one was made postopertively. The large number of preoperative wrong diagnoses leads to the demand to only operate after extensive exploratory excisions.

Adolescent↗
PubMed1980

[Primary malignant mesenchymal tumors in the head and neck area--the problems in diagnosis and therapy (author's transl)].

The problems in diagnosis and therapy of malignant mesenchymal tumors in the head and neck area are reported on. The clinical course and the pathology of these rare tumors are described. First hand experiences with certain cases--one malignant leiomyoma, two rhabdomyosarcomas (one of embryonal and one of pleomorphic type), a haemangiopericytoma, a haemangioendothelioma, a chondrosarcoma and two malignant synovialomas are detailed and compared with similar case-studies in the literature.

Adult↗
PubMed1979

The pharmacological relevance of vital staining with neutral red.

The uptake of neutral red into the renin-containing juxtaglomerular granules does not inhibit the release of renin either in basal or in stimulated states of renin secretion. The vasodilating effect of neutral red may be due to a nonspecific binding to noradrenaline-receptors in the vascular smooth muscle cells.

Angiotensin II↗