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Biomedical subjects

E Pósch

Publications and source records attributed to E Pósch.

At least 19 recordsLinked to original sources

Renal hypertrophy in streptozotocin-diabetic rats.

In male adolescent rats kidney mass attained maximum terminal value already at week 1 after streptozotocin treatment, and this value did not change over the next two weeks. At week 1 the kidney size of diabetic rats was greater than that of untreated controls, whereas at week 3 renal mass was the same in both groups. In adult rats with final body and kidney mass streptozotocin treatment failed to induce further increment in renal growth, and the kidney size of diabetic animals was the same as the final kidney size of age-matched control animals. The identity of terminal maximum values for kidney mass in male rats suggests rather an accelerated kidney growth than a true hypertrophic response in diabetes. Similar conclusion can be drawn from our observations made on the compensatory growth of the solitary kidney in diabetic rats with prior uninephrectomy.

Animals↗

[The effect of H2-receptor blockers (cimetidine and ranitidin) on parotid gland secretion and salivary carbonic anhydrase activity in the rat].

It has been demonstrated, that the H2-receptor antagonists: cimetidine and ranitidine-administered in doses of the same order of magnitude as reported for the inhibition of rat gastric secretion and development of the experimentally induced gastric and duodenal ulcer-are capable of increasing significantly the parotid secretion evoked by the cholinergic stimulant bethanechol. The salivary carbonic anhydrase activity was also elevated after combined treatment of bethanechol(+)-cimetidine. The similar action of the two H2-antagonists appears to suggest that their effect on salivation is connected probably with the cholinergic activity and it is concluded that the combination of bethanechol with these blockers may improve the esophageal clearance, an action that may be beneficial in the treatment of the gastroesophageal reflux disease.

Animals↗

Effect of denervation on the neurogenic inflammation of the rat mandibular mucosa.

Effects of local exposure to capsaicin on the vascular permeability and blood flow were studied in the rat oral mucosa at days 2 and 14 after the unilateral transection of the inferior alveolar nerve (IAN). The distribution of nerve fibers displaying substance P (SP) and calcitonin gene-related peptide (CGRP) immunoreactivity (IR) in the mandibular mucosa was also assessed. While the capsaicin-induced augmentation in vascular permeability was about 50% (P less than 0.05) higher on the intact side (at both days 2 and 14) than on the denervated side, no difference in blood flow elevation was seen between the two sides. Transection of IAN caused only a slight reduction in the density of SP- and CGRP-IR fibers in the mucosa. It is concluded that in addition to the IAN fibers the mandibular mucosa examined also seems to be supplied by other sensory fibers. The presence of accessory trigeminal branches was also supported by immunohistochemical studies.

Animals↗

Role of histamine in the development of neurogenic inflammation of rat oral mucosa.

The mechanism of development of neurogenic inflammatory reaction induced by the topical application of capsaicin was studied in the oral mucosa of rats with or without histamine antagonist pretreatment. The existence of a cholinergic component of the vasodilation was investigated using a muscarinic receptor antagonist. Results indicated that the neurogenic inflammatory increases in vascular permeability and blood flow are mediated in part by H1-receptors, H2-receptors and cholinergic pathways are apparently not activated in these processes.

Animals↗

[The role of histamine in neurogenic inflammations of the mouth mucosa in rats].

The effect mechanism of neurogen inflammation incited by local capsaicin irritation was examined by the authors in the oral soft tissue of rats subsequent to antihistamin pretreatment. Furthermore, with the aid of muscarin blocking receptor also the parasympathetic component of the vasodilatation was examined. On basis of their results it was established that the vein-wall-permeability and microcircular changes observed in the course of the neurogen inflammation of the oral soft tissue partly expanded by the histamin through the H1-receptors. The H2-receptors as well as the parasympathetic fibers do not become activated in the process.

Animals↗

[The effect of the transsection of the inferior alveolar nerve on neurogenic inflammation of the mouth mucosa. II. Immunohistochemical studies].

The distribution of nerve fibers displaying calcitonin gene-related peptide (CGRP) immunoreactivity in the mandibular mucosa was studied in control rats, in rats after unilateral transection of the inferior alveolar nerve (IAN), and in animals following cervical sympathetic denervation. According to the results, the transection of the peripheral branch of the IAN has no effect on the distribution of the CGRP immunoreactive nerves.

Animals↗

[The effect of transsection of the inferior alveolar nerve on neurogenic inflammation of the oral mucosa. I. Functional studies].

Vascular effects of local capsaicin treatment has been studied on the 2nd and 14th days subsequent to unilateral inferior alveolar nerve (IAN) transection in the oral mucosa of rats. The results suggest, that the symptoms of neurogenic inflammation were influenced by the transection of IAN in a different way. The reason of that is the different mechanism in the development of the symptoms and/or the different compensatory capacity of the accessorial nerves.

Animals↗

Experimentally-induced neurogenic inflammation in the rat oral mucosa.

Blood flow and vascular permeability in the gingiva and alveolar mucosa of the lower jaw were studied after the antidromic (electric) or orthodromic (topical administration of capsaicin onto the oral mucosa) stimulation of the inferior alveolar nerve (IAN) in rats with or without capsaicin pretreatment. Blood flow was determined using 86Rb isotope dilution technique, while vascular permeability was assessed by the Evans blue extravasation. Both antidromic or orthodromic stimulation of the IAN increased blood flow and Evans blue extravasation. Capsaicin pretreatment abolished the increase in gingivo-mucosal blood flow and vascular permeability induced by nerve stimulation. The results of the present study appear to confirm the possibility of the development of neurogenic inflammation in the oral cavity. The mechanism observed may play a role in the development of certain inflammatory reactions in the oral mucosa frequently encountered in human clinical practice.

Animals↗

Diuretic and natriuretic actions of extract prepared from rat erythrocytes.

Freeze-dried preparation of rat erythrocytes was extracted into distilled water and after heat treatment the extract was chromatographed on Sephadex G-25 column. The effluent fractions were pooled, freeze-dried, dissolved in Ringer's solution and bioassayed for diuretic and natriuretic responses in anaesthetized non-diuretic rats. The active fractions potently enhanced urine output (about 9-fold control) and urinary sodium excretion (about 7-fold control). The responses started to develop after a lag period of approximately 10-20 min, peaked between 60-80 min post-injection and then diminished. The augmentation of sodium excretion persisted longer than the increased diuresis. The biological activity of the extract was retained after dialysis in a tube with nominal molecular weight cut-off below 1,000.

Animals↗

Effect of indomethacin on the bradykinin-induced vasodilation in the submandibular gland.

Effects of the local infusion of bradykinin or isoproterenol were studied on the systemic blood pressure, blood flow, and vascular resistance of the submandibular gland before and after indomethacin treatment in cats. Both bradykinin and isoproterenol were shown to potently increase the glandular perfusion rate. The systemic arterial blood pressure fell by about 20% in response to indomethacin. The enhancement of blood flow by bradykinin or isoproterenol was not, however, affected by indomethacin treatment. The present results appear to suggest that the endogenous prostaglandins are not essentially involved in the development of responses produced by bradykinin or isoproterenol in the cat submandibular gland.

Animals↗

Myasthenia gravis: long-term prognostic value of thymus lactate dehydrogenase isoenzyme pattern of hyperplastic thymus and thymoma.

Lactate dehydrogenase (LDH) isoenzyme pattern and the percent of H-subunit content were determined in the thymus of 62 patients (55 with hyperplasia, 7 with tumours) after thymectomy. An increase in LDH1 relative activity indicates that in the thymus of patients with myasthenia gravis the ratio of mature differentiated thymocytes was higher than in the thymus of control subjects. LDH isoenzyme profiles of thymus tumours were similar to those described in other neoplasms, except that thymomas with apparent predominance of epithelial cells and with minimal lymphocytic reaction exhibited a marked elevation only in LDH2 relative activity, presumably associated with the specific (secretory) function of epithelial cells. The elevation of H-subunit content, a parameter characteristic of both thymic components (lymphoid and epithelial), correlated closely with a poor clinical condition in patients several years after surgery.

Adolescent↗

Effect of indomethacin on the blood flow of the rabbit submandibular gland.

Effects of the stimulation of the chorda tympani and acetylcholine infused into the artery of the gland were studied on the blood flow and saliva secretion of the rabbit submandibular gland before and after indomethacin treatment. The enhancement of blood flow and saliva secretion was less apparent after indomethacin than before. Results suggest that endogenous prostaglandins are also involved in the mechanism of the augmentation of blood flow and saliva secretion produced by the stimulation of the chorda tympani in the rabbit submandibular gland.

Acetylcholine↗