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Biomedical subjects

R Dietz

Publications and source records attributed to R Dietz.

At least 19 recordsLinked to original sources
PubMed1992

Target size analysis of prostaglandin endoperoxide synthase. Radiation inactivation of both cyclooxygenase and peroxidase correlated with the monomer of 72 kDa.

To determine the size of the functional catalytic unit of prostaglandin endoperoxide (prostaglandin H) synthase, radiation inactivation experiments were performed. Both microsomes from ovine seminal vesicles and purified enzyme were irradiated with 10 MeV electrons. The enzymic activities of prostaglandin H synthase, cyclooxygenase and peroxidase, showed mono-exponential inactivation curves dependent on radiation dose, indicating molecular masses of approximately 72 kDa. The enzyme in microsomes, in its native environment, as well as in its purified state after solubilisation with nonionic detergent showed identical molecular masses. The results clearly demonstrate that the monomer of the enzyme with an apparent molecular mass of 72 kDa (SDS/PAGE) is the functional unit for catalysis of both activities. Hence the two active sites of cyclooxygenase and peroxidase reside on the same polypeptide chain.

Animals↗
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↗
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↗