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Biomedical subjects

R Dietz

Publications and source records attributed to R Dietz.

At least 307 records · Page 17Linked to original sources
PubMed1979

Effects of an orally active converting-enzyme inhibitor, SQ 14225, on pressor responses to angiotensin administered into the brain ventricles of spontaneously hypertensive rats.

1. Two hours after oral feeding of normotensive Wistar Kyoto rats with the converting-enzyme inhibitor SQ 14225 (1 and 10 mg/kg), an increase of angiotensin I plasma concentrations from 892 +/- 113 to 1660 +/- 167 and 2951 +/- 405 pg/ml was observed. 2. Administration of SQ 14225 with the drinking fluid overnight suppressed the pressor responses to intravenous angiotensin I, although the blood pressure increase after intravenous angiotensin II was not altered in normotensive and spontaneously hypertensive rats. No change of pressor effects after injections of angiotensin I and II into the brain ventricles was observed after oral SQ 14225. 3. Intracerebroventricular infusions of SQ 14225 in spontaneously hypertensive rats abolished the central pressor responses to angiotensin I. 4. The results show that SQ 14225 effectively blocked the conversion of endogenous and exogenous angiotensin I into angiotensin II in plasma, and the conversion of exogenous angiotensin I in brain. Under the conditions studied, SQ 14225 does not cross the blood-cerebrospinal fluid barrier in spontaneously hypertensive rats.

Administration, Oral↗
PubMed1979

Effect of neonatal sympathectomy by 6-hydroxydopamine on volume and resistance regulation in stroke-prone spontaneously hypertensive rats.

1. Neonatal sympathectomy with 6 hydroxy-dopamine (6-OHDA) was used as a tool to assess the significance of an increased sympathetic vascular tone for the development of high blood pressure in stroke-prone spontaneously hypertensive rats. After administration of 6-OHDA the rise in blood pressure was blunted for the following 9 weeks until innervation was re-established. 6-OHDA-treated rats retained more sodium and had larger plasma and blood volumes than sham-treated rats. 2. Catecholamines in plasma were increased 2-10-fold immediately after sympathectomy, but their concentrations were subnormal on day 7. Eight weeks after sympathectomy plasma noradrenaline and dopamine were not elevated, but plasma adrenaline has increased twofold. 3. The reactivity of resistance vessels to noradrenaline was markedly enhanced and the neuronal uptake and metabolism of noradrenaline were still reduced 8 weeks after neonatal sympathectomy. 4. These results confirm the significance of an intact sympathetic nervous system for the development in these rats. Sodium retention and increased plasma and blood volume may be considered as a compensatory mechanism for the vasodilatation resulting from decreased vasomotor tone.

Animals↗
PubMed1979

Modulation of sympathetic vascular tone by prostaglandins in corticosterone-induced hypertension in rats.

1. In corticosterone-induced hypertension in rats the activity of the peripheral sympathetic nervous system and its modulation by prostaglandins was studied. 2. Plasma concentrations of noradrenaline were reduced if compared with those in normotensive control rats. 3. The sensitivity of the isolated perfused hind-limb preparation to noradrenaline was enhanced before blood pressure rose and increased further with the development of hypertension. 4. Arachidonic acid, prostacyclin (prostaglandin I2), but not 6-keto-prostaglandin F1 alpha, reversed the supersensitivity to noradrenaline. 5. These results suggest that corticosterone induces a supersensitivity to noradrenaline by inhibiting the biosynthesis of prostaglandins. Changes in the sensitivity of the vascular smooth muscle may play a role in the development of glucocorticoid hypertension.

Animals↗
PubMed1979

[Contribution to combined therapy of the Ewing-sarcoma (author's transl)].

The techniques and results from the treatment of 15 own cases with Ewing-sarcoma having undergone different therapeutic schemes are reviewed with the help of universal literature. These tumors are shown to need individual treatment which has to be adapted to the present data in each case.

Adolescent↗
PubMed1979

[Therapy in cancer of the male breast (author's transl)].

Six patients with carcinomas of the breast are reported. Bienergetic pendulum irradiation with electrons is applied following surgical treatment in the same manner as with female patients. The possibilities of metastasition treatment are discussed.

Adult↗
PubMed1979

[Results of treatment of breast cancer with a betatron (author's transl)].

The authors analyze the results of post-operative therapy with accelerated electrons from a betatron, more especially with pendular bi-energetic electrontherapy, applied to 459 patients with various stages of breast cancer. They stress that as well as the favourable survival rate, sequelae were rare, and there were very few local recurrences.

Adult↗
PubMed1979

[Pre-operative irradiation and tumor-specific immune response in hypernephroid renal carcinoma (author's transl)].

In vitro demonstration of a tumor-specific immune response was tried using the so-called leucoycte migration test in altogether 32 patients with a hypernephroid renal carcinoma (nontreated before operation or pre-irradiated). The principle of this technique consists in the release of a lymphocyte factor by bringing in contact sensitized lymphocytes with the concerned tumourous tissue, the lymphocyte factor inhibiting the migration capacity of granulocytes. With hypernephroid cancerous tissue from nontreated patients no reaction was obtained in 12 of 13 cases (no inhibition of migration), whereas a positive reaction (inhibition of leuococyte migration) was observed in 17 out of 19 patients with hypernephromas having been irradiated before surgical treatment. This radiation-induced effect on the immune response from hypernephroma and lymphocytes in patients with this neoplasm is specific, as no reaction of irradiated hypernephroid cancerous tissue with lymphocytes of sound donors or of patients with different malignant tumors could be shown in control tests, a significant inhibition of leucocyte migration failing to appear.

Adenocarcinoma↗
PubMed1979

[Ten years experience with combination therapy for tonsillar malignancies (author's transl)].

From 1968 to 1978, 125 patients with cancer of the tonsil have been treated by the Departments of Radiology and Otolaryngology at the University Hospital, Homburg-Saar. Although all patients were unirradiated, many had previously undergone a surgical procedure. Most of the cancers when seen were in advanced stages. The three-year and five-year survival rates were 38.6 and 23.5% respectively. Reticulum cell sarcomas, Schmincke's tumors and non-keratinized squamous cell carcinomas had better prognoses than keratinized squamous cell carcinomas. Our findings indicate that the volume of large tumors should be reduced by surgical means before irradiation since irradiation alone resulted in a higher relapse rate in the advanced cancers. Various methods for radiotherapy either before or after surgery for different tumor stages are discussed. The combination of chemotherapy with radiation to make use of the so-called "partial synchronisation effect" in cases of inoperable extensive primary tumors or relapses is described.

Adult↗
PubMed1979

[Behaviour of the peripheric leucocyte count and leucocyte resistance in rat after acute whole-body irradiation with 60Co-gamma-rays (author's transl)].

Wistar-rats were exposed to whole-body 60Co gamma irradiation and underwent continuous blood analysis through 70 days. By means of these experiments information as to the reliability of "values of the leucocyte resistance against ultrasound (LRW)" should be obtained in order to diagnose radiation injury. For all the dose ranges studied (from 10 R to 500 R) it was possible to ascertain a qualitatively radiation-specific LRW-curve being independent of the behaviour of peripheric leucocyte counts.

Animals↗
PubMed1979

[Tumor-specific immune response of hypernephroid renal carcinoma after in vitro irradiation (author's transl)].

It is possible to reproduce in vitro the induction in the leucocyte migration test of an immune response specific to hypernephroid carcinoma by preoperative radiation treatment of this neoplasm. The leucocyte migration is inhibited by soluble extracts of the tumor, prepared from hypernephroma-tissues (of 11 patients nontreated preoperatively) after in vitro irradiation either with electrons or with 60Co. This effect depends on the dose. The radiation dose producing a maximal inhibition following in vitro irradiation is nearly equal to that delivered by us before surgical treatment.

Adenocarcinoma↗
PubMed1978

Reversal of renal hypertension: effects on renin, salt and water balance.

The effect of removal of one renal artery stenosis on renal sodium and fluid excretion and on the activity of the renin-angiotensin system (RAS) has been investigated in three types of renal hypertension of rats. Blood pressure fell in all experimental models after declamping, independently of changes in urinary sodium and water excretion or plasma angiotensin II (ANG II). Plasma concentrations of ANG II did not rise in response to salt and fluid loss induced by declamping when the contralateral kidney had been removed or when it was depleted from renin. A high renin content of the declamped kidney prevented major salt and fluid loss, whereas renin depletion of this kidney was accompanied by an exaggerated natriuresis and diuresis. Besides this tubular modulation of renal salt and water handling by the local RAS, glomerular filtration rate could be reduced by a stimulated activity of this system in plasma, indicated by a close relationship between serum urea and plasma ANG II levels.

Angiotensin II↗
PubMed1978

Inhibition of the renin-angiotensin-system in Brattleboro rats with hereditary hypothalamic diabetes insipidus.

Brattleboro rats homozygous for hypothalamic hereditary diabetes insipidus (DI rats) were used to investigate the following questions: a) Do exogenous and endogenous angiotensin II (AII) have an antidiuretic effect in diabetes insipidus? b) Does AII mediate the antidiuresis induced by furosemide? The following results were obtained: 1. AII (5 mg/kg s.c. in oil) and furosemide (50 mg/kg i.p.) decreased urine flow and increased urinary sodium excretion. Furosemide led to a two-fold increase of AII plasma concentrations and a decrease of plasma sodium levels. 2. SQ 14 225 (2 x 2.5 mg/kg p.o.), an angiotensin I-converting enzyme inhibitor, led to an increase of urine flow and to a slightly elevated urinary sodium excretion. 3. When the formation of AII was blocked by SQ 14 225 (2 x 2.5 mg/kg p.o.), AII plasma concentrations were 2.5-fold decreased, but furosemide still reduced urine flow. We conclude that plasma AII might have an antidiuretic action in DI rats. However, AII does not mediate the antidiuresis induced by furosemide.

Angiotensin II↗