Role of endothelins in regulation of vascular tone in the in situ perfused rat adrenals.

This study examined the role of endothelins (ETs) and their receptor subtypes ETA and ETB in the regulation of vascular tone in the in situ perfused rat left adrenal gland. Endothelin-1 (ET-1), which binds both ETA and ETB receptors, decreased adrenal flow rate of the perfusion medium, and its effect was reversed by the ETA antagonist BQ-123 and enhanced by the ETB antagonist BQ-788. ET-3, which preferentially binds ETB, and the selective ETB agonist BQ-3020 increased adrenal flow rate of perfusate, and their effects were annulled by BQ-788.

Intra-adrenal 11 beta-hydroxysteroid dehydrogenase plays a role in the regulation of corticosteroid secretion: an in vitro study in the rat.

The expression of 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) has been demonstrated in the adrenal glands, but until now little attention has been paid on its possible physiologic action. In-situ perfused rat adrenals released under basal conditions, in addition to mineralo- and glucocorticoids, notable amounts of 11-dehydrocorticosterone (DH-B), the inactive form to which corticosterone (the main glucocorticoid in rodents) is converted by 11 beta-HSD. The addition to the perfusion medium of glycyrrhetinic acid, a specific inhibitor of 11 beta-HSD, strongly reduced DH-B release and simultaneously evoked a moderate rise in both mineralo- and glucocorticoid output.

Adrenomedullin stimulates steroid secretion by the isolated perfused rat adrenal gland in situ: comparison with calcitonin gene-related peptide effects.

Adrenomedullin (ADM), a vasodilatatory peptide contained in adrenal medulla, was found to induce a dose-dependent increase in aldosterone (ALDO) and corticosterone (B) release by the in situ perfused rat adrenal gland, along with a rise in the flow rate of the perfusion medium. The minimal effective dose for ALDO response was three and two orders of magnitude less than those able to evoke B and medium flow rate responses. Calcitonin gene-related peptide (CGRP), another vasodilatatory peptide contained in adrenal medulla and showing a slight homology in its amino acid sequence with ADM, elicited similar effects.

Evidence that endogenous vasoactive intestinal peptide (VIP) plays a role in the maintenance of the growth and steroidogenic capacity of rat adrenal zona glomerulosa.

The effects of a 7-day intraperitoneal infusion with VIP (0.03 nmol.kg-1.

Evidence that endogenous somatostatin (SRIF) exerts an inhibitory control on the function and growth of rat adrenal zona glomerulosa. The possible involvement of zona medullaris as a source of endogenous SRIF.

The effect of SRIF and its antagonist cyclo(7-aminoheptanonyl-Phe-D-Trp-Lys-Thr magnitude of Bzl)(SRIF-A) were studied in sham-operated and bilaterally adrenalectomized rats bearing ACTH- and angiotensin II (ANG-II)-responsive adrenocortical autotransplants. SRIF-A (10(-5) M) completely annulled SRIF (10(-6) M)-induced inhibition of ANG-II (10(-8) M)-evoked rise in aldosterone (ALDO) secretion by both dispersed zona glomerulosa (ZG) cells and autotransplant slices. A 7-day intraperitoneal infusion with SRIF (0.

A comparative study of the effect of atrial natriuretic peptide (ANP) on the secretory activity of rat adrenal cortex and angiotensin-II-responsive adrenocortical autotransplants.

Rat adrenocortical autotransplants regenerated from capsular-tissue fragments implanted in the musculus gracilis displayed an in-vitro basal gluco- and mineralocorticoid secretion qualitatively similar to that of adrenal quarters from control rats. Moreover, like adrenal quarters, they responded to angiotensin-II (Ang-II, 10(-8) M) by raising their yield of 18-hydroxylated steroids (18-hydroxy-11-deoxycorticosterone, 18-hydroxycorticosterone and aldosterone). ANP (10(-8) M), one of the main negative modulators of the zona-glomerulosa (ZG) mineralocorticoid secretion, totally blocked the ANG-II stimulating effect on adrenal quarters, but not that on adrenocortical autotransplants.

Interleukin-1beta Stimulates Corticotropin-Releasing Hormone (CRH) and Adrenocorticotropin (ACTH) Release by Rat Adrenal Gland in Vitro.

CRH and ACTH immunoreactivities (ir) were present in rat adrenal glands but not in adrenocortical autotransplants lacking chromaffin cells. Interleukin-1beta (IL-1beta) dose-dependently elicited CRH-ir and ACTH-ir release by decorticated adrenal fragments mainly composed of zona-medullaris tissue; the minimum effective concentration was 10(-10)/10(-8)M, and the maximal one was 10(-6)M. The IL-1beta (10(-6)M)-induced ACTH release by our preparations was completely blocked by alpha-helical-CRH (10(-6)M), a competitive inhibitor of CRH.

Evidence that endogenous arginine-vasopressin (AVP) is involved in the maintenance of the growth and steroidogenic capacity of rat adrenal zona glomerulosa.

A 7-day subcutaneous infusion with the AVP antagonist [Deamino-Pen1, Val4, D-Arg8]-vasopressin (AVP-A; 3 nmol.kg-1 x min-1) significantly lowered plasma aldosterone concentration in rats, without affecting the plasma levels of ACTH and corticosterone. Prolonged AVP-A treatment caused a marked atrophy of adrenal zona glomerulosa (ZG) and its parenchymal cells, without inducing any significant change in zona fasciculata morphology.

Arginine-vasopressin release mediates the aldosterone secretagogue effect of neurotensin in rats.

Acute and chronic systemic administrations of neurotensin (NT) and arginine-vasopressin (AVP) significantly increases plasma aldosterone concentration (PAC) in rats. Deamino-Pen1, Val4, D-Arg8-vasopressin (AVP-A), a potent AVP antagonist, completely reversed both acute and chronic aldosterone secretagogue actions of NT and AVP. AVP-A acute administration did not affect basal PAC, while chronic AVP-A treatment significantly lowered it.

Fetus in fetu removal in a 47-year-old man.

A case of removal of a fetus in fetu in a 47-year-old man is reported. The patient had an upper abdominal mass since birth that had never caused any subjective symptoms. A preoperative computed tomographic scan was useful to confirm the diagnosis.

Direct secretagogue effect of corticotropin-releasing factor on the rat adrenal cortex: the involvement of the zona medullaris.

CRF dose-dependently enhanced corticosterone (B) secretion by rat adrenal slices including both cortex and medulla. Conversely, CRF did not exert any B response by fragments of adrenocortical autotransplants, which are completely deprived of chromaffin tissue. However, autotransplant quarters exhibited a dose-dependent response to ACTH qualitatively similar to that of adrenal slices, although markedly less intense.

The influence of environmental pressure on retentiveness of prosthetic crowns: an experimental study.

To determine the effect of pressure variations on the retention of prosthetic crowns, 36 identical, cast metal crowns were fixed to simulated, epoxy resin crown preparations with zinc oxyphosphate cement. Eighteen specimens were placed in a hyperbaric chamber and subjected to 15 cycles of simulated immersion at 30 m and decompression, as usually carried out by scuba divers. The untreated specimens served as controls.

Increase in vascular permeability produced in rat airways by PAF: potentiation by adrenalectomy.

1. The effect of bilateral adrenalectomy on the sensitivity of blood vessels in rat airways to mediators that increase vascular permeability was examined. 2.

Effects of prolonged sodium restriction on the morphology and function of rat adrenocortical autotransplants.

Regenerated adrenocortical nodules were obtained by implanting fragments of the capsular tissue of excised adrenal glands into the musculus gracilis of rats (Belloni et al. 1990). Five months after the operation, operated rats showed a normal basal blood level of corticosterone, but a very low concentration of circulating aldosterone associated with a slightly increased plasma renin activity (PRA).

Effects of prolonged treatment with adrenocorticotropin on the morphology and function of rat adrenocortical autotransplants.

Regenerated adrenocortical nodules were obtained by implanting in the musculus gracilis of rats fragments of the capsular tissue of their excised adrenal glands. Five months after operation, transplanted rats showed a slightly elevated blood concentration of adrenocorticotropin (ACTH), a moderately reduced plasma level of corticosterone (PBC) and a very low concentration of circulating aldosterone (PAC). Regenerated nodules were well encapsulated, and from the connective capsule some septa dipped into the parenchyma.

Investigations on the morphology and function of adrenocortical tissue regenerated from gland capsular fragments autotransplanted in the musculus gracilis of the rat.

This paper describes the function and morphology of regenerated adrenocortical nodules obtained by implanting, in the musculus gracilis of rats, several (n = 6-7) fragments of the capsular tissue of their excised adrenal glands. Four months after the operation, each bilaterally adrenalectomized rat developed six or seven well encapsulated adrenocortical nodules about 2-3 mm in diameter and always lacking chromaffin cells, and displayed almost complete normalization of basal and stimulated blood levels of corticosterone, but not of aldosterone. In vitro study showed that regenerated nodules were well functioning as far as glucocorticoid production was concerned.

[Major hepatectomies in liver neoplasms].

The development of major hepatic resective surgery during the last 50 years is due to a better knowledge of both hepatic regenerative capacity and intraparenchymal vascular and biliary anatomy. Two approaches of major hepatic resection have been described: 1) primary hilar approach; 2) primary transparenchymal approach. The authors review the indications of major hepatic resections in the treatment of hepatic tumors and discuss the advantages and the disadvantages of primary hilar and primary transparenchymal approaches, reviewing the data from the literature and the experience gained at the Clinica Chirurgica of the University of Verona from 1970 to 1989 of 289 major hepatic resections.

[Biliary cystadenoma and cystadenocarcinoma].

The authors present their experience with 5 biliary cystadenomas (BCA) and 1 cystadenocarcinoma (BCAC). BCA are rare but intriguing lesions of the liver for the possibility of the former to evolve into malignant lesion. Preoperative diagnosis is often difficult also at ultrasound and CT scan.

[Zuckerkandl tubercle of the thyroid gland (anatomo-surgical study: preliminary considerations)].

The presence of tubercle of Zuckerkandl (TZ) of the thyroid gland has been investigated in 20 specimens obtained from patients died from diseases not concerned to the cervical area. The project mas undertaken to elucidate the presence and the role of TZ as normal anatomical landmark. Special attempt has been paid to the relationships of the TZ with parathyroid gland and recurrent laryngeal nerve and the branches of the inferior thyroid artery.