Effects of beta-adrenergic blocking agents on peripheral vascular resistance

The effects of the beta-adrenergic blocking agents propranolol, pindolol, atenolol, bunitrolol, and methypranol on the vascular resistance of isolated perfused hindlimbs of rats were investigated. At concentrations of 0.01 microgram/ml in the perfusate dl-propranolol and pindolol significantly increased vascular resistance by blockade of beta2-receptor mediated vasodilatation, whereas atenolol, bunitrolol and methypranol had no effect on peripheral resistance at this concentration. With increasing concentrations up to 10 microgram/ml all drugs, with the exception of atenolol, caused vasodilatation. We conclude that the specificity of beta-blocking agents can be established in the isolated perfused hindlimb vasculature of rats through its effect on vascular resistance. The lack of inhibition of vascular beta2-receptors at low concentrations of atenolol and also bunitrolol and methypranol show relative selectivity for beta1-receptors. The differential effects of beta-adrenergic agents on vascular resistance may have significance for the clinical use of the drugs.

[Prostate carcinoma: determination of progression following high-voltage therapy (author's transl)]

The fourth report of our long-term study concerns 70 cases of primary radiotherapy. The side effects of our radiation technique are minimal and temporary; in over 80% of the cases, potency was not affected. The morphologically demonstrable changes in the tumor tissue, in the original glandular parenchyma, and in the fibromuscular stroma leading to the vessels following high-voltage therapy are described. Three types of progressive patterns, based on the grade of histologic regression, can be determined. In more than half of the cases, with increasing distance from the source of radiation, no tumor or only minimal residual tumor was demonstrable. Sensibility and resistance of carcinoma of the prostate are not dependent upon the grade of differentiation of the tumor. A prognostic statement concerning the success of radiation therapy from initial histologic findings is not possible here. The occurrence of metastases in 18% of the cases following radiation probably resulted from the inexactness of the purely clinical determination of the stage of the tumor. The isolated, local treatment of prostate carcinoma through radiotherapy is justified only after exact determination of the stage of the tumor, i.e., certain exclusion of metastases via a diagnostic lymphadenectomy.

Irreversible shock in rats after injection of microspheres into the renal artery

After injection of microspheres into both renal arteries of rats, an irreversible shock syndrome develops, resulting in death within 4-12 h. Ligation of both renal pedicles after injection of microspheres prevents the shock. It is presumed that kininogenases released from the kidneys participate in the pathogenesis of the shock syndrome.

Changes in vascular smooth muscle sensitivity to vasoconstrictor agents induced by corticosteroids, adrenalectomy and differing salt intake in rats

1. Isolated hind limbs of rats were perfused and vascular smooth muscle sensitivity to noradrenaline, methoxamine and potassium chloride was measured and dose-response curves were obtained. 2. The sensitivity of vascular smooth muscle to noradrenaline is attenuated by adrenalectomy and low sodium diet; it is enhanced by corticosterone. High sodium diet or administration of deoxycorticosterone did not alter the dose-response curve significantly. 3. The increased sensitivity of vascular smooth muscle after corticosterone treatment is not related to changes in the contractile protein or alterations in the neuronal uptake and extraneuronal metabolism of noradrenaline. 4. These results suggest that the increased sensitivity in corticosterone-treated rats may be due to the number of receptors, receptor affinity to noradrenaline, or changes in the functional link between receptor and contractile apparatus.

Does the renin-angiotensin system contribute to the vascular lesions in renal hypertensive rats?

1. Renal hypertensive rats with a normal or suppressed activity of the renin-angiotensin system develop vascular lesions which are similar to those observed in spontaneously hypertensive rats on high sodium diet. 2. Exposure of a vascular bed to high blood pressure results in a rapid damage of the vascular wall, irrespective of the state of the renin-angiotensin system.

[Radiotherapy of pinealoma]

The possible methods of radiation therapy of the pinealoma are treated with regard to two own cases. The methods used by other therapeutists are also taken into consideration. The dose distribution in the target volume and the surrounding volume is discussed for different irradiation methods. The troubles felt by the two persons (a girl of 15 years and a boy of 15 years) were declining continually during the radiation therapy.

[Rare localization of a reticulum-cell sarcoma in the clavicular epiphysis]

The unusual case of a reticulum cell sarcoma in the clavicular epiphysis gives occasion to discuss the problems of diagnosis and therapy of this tumor and to point out difficulties met with in the early identification of the clinical picture of this disease.

Salt loss as a possible mechanism eliciting an acute malignant phase in renal hypertensive rats

1. The acute malignant phase of hypertension in rats with an untouched contralateral kidney is characterized by salt and fluid loss, increased fluid intake, decrease in body-weight gain, and reduced food consumption. Plasma concentrations of sodium and potassium were reduced, and plasma angiotensin II rose to about four times normal. 2. To investigate the significance of an untouched contralateral kidney for the development of the acute malignant phase in renal hypertensive rats, comparative studies were undertaken in unilaterally nephrectomized rats with stenosis of the remaining renal artery and in rats with bilateral renal artery stenosis. In addition, the effect of declamping one renal artery in rats with bilateral stenosis was studied. 3. In unilaterally nephrectomized rats, no signs of sodium and fluid loss were demonstrable, despite marked increase in blood pressure. Similarly, rats with bilateral renal artery stenosis had no acute malignant phase of hypertension. 4. In hypertensive rats with bilateral stenosis, removal of the clip from one renal artery was followed by an immediate fall in blood pressure and a subsequent gradual increase. Eleven of sixteen rats lost salt and fluid and developed an acute malignant phase. Plasma angiotensin II was high and serum urea elevated. 5. Consumption of 2% saline in addition to water as drinking fluid had a beneficial effect, since only five of fourteen rats showed signs of the acute malignant phase, which were milder than in rats on water only. 6. It is concluded that the untouched contralateral kidney is responsible for the negative salt and water balance and its consequences, which are characteristic of the acute malignant phase of experimental renal hypertension.

[Differential diagnosis of struma maligue]

With reference to a case in which the scintigram showed an autonomous adenoma with a cold area that histologically, however, turned out to be a carcinoma of the thyroid gland, the diagnostical problems of thyroid cancer and the various possibilities in the differential diagnosis are demonstrated.

Aldosterone and corticosterone production in renal hypertensive rats

The development of hypertension, which had been elicited by clamping one renal artery in the presence of an untouched contralateral kidney, has been pursued in rats for up to six weeks after operation, and aldosterone and corticosterone production was studied at various intervals.

The renin-angiotensin system in acute renal failure of rats

1. Acute renal failure was produced in rats by intramuscular injection of glycerol. Subsequently, changes in the concentrations of renin and of angiotensin II in plasma and the renin content of the kidneys were followed. 2. at 4 and 8 h after glycerol administration, plasma renin and angiotensin II had increased two to three-fold; they remained elevated for 48 h and then returned towards normal. At 7 days, the values were still slightly raised. 3. At 4 and 8 h after glycerol injection, kidney renin had decreased but it had increased after 24 and 48 h. 4. Passive immunization with angiotensin II antibodies, given at the time of glycerol injection and 2 and 4 h afterwards, prevented the development of acute renal failure. When angiotensin II antiserum was administered later (8, 10 and 12 h after glycerol) it had no effect. 5. Stimulation of the renin-angiotensin system may be involved in the pathogenesis of the early phase of acute renal failure.