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G Rindi

Publications and source records attributed to G Rindi.

At least 127 records · Page 7Linked to original sources
PubMed1988

Effect of acute and chronic ethanol administration on the transport of thiamine from plasma to different brain regions of the rat.

The effect of ethanol (4.7 g/kg body wt intragastrically as a single dose or once daily for 35 days) on the transport of thiamine from plasma to four brain regions (cerebellum, cerebral cortex, pons and medulla) was studied in albino rats. Animals were given an intravenous injection of labelled thiamine with a sampling procedure which allowed the determination of regional blood flow and tissue thiamine uptake. Regional blood flow was found to be enhanced after acute, but non chronic, ethanol administration. The magnitude of increase ranged from 13 to 35% depending on the brain region being considered. Thiamine was transferred from plasma to cerebral tissue by a saturable process with a non-saturable component prevailing at thiamine concentrations above 10-15 microM. Three main modifications in the thiamine transport were found as a result of ethanol treatment: a reduction in affinity for the carrier (Km increased), an increase in maximal transport rate (Jmax) and an increase in non-saturable diffusion (KD constant increased). The effects were more pronounced after acute ethanol administration. As a consequence of these modifications both acute and chronic ethanol treatment caused an increase in thiamine transport rate at high plasma concentrations. On the contrary, at low (physiological) plasma concentrations, thiamine transport was little increased by acute ethanol administration and virtually unaffected by chronic ethanol intoxication.

Alcoholic Intoxication↗
PubMed1987

Endocrine cells producing regulatory peptides.

Recent data on the immunolocalization of regulatory peptides and related propeptide sequences in endocrine cells and tumors of the gastrointestinal tract, pancreas, lung, thyroid, pituitary (ACTH and opioids), adrenals and paraganglia have been revised and discussed. Gastrin, xenopsin, cholecystokinin (CCK), somatostatin, motilin, secretin, GIP (gastric inhibitory polypeptide), neurotensin, glicentin/glucagon-37 and PYY (peptide tyrosine tyrosine) are the main products of gastrointestinal endocrine cells; glucagon, CRF (corticotropin releasing factor), somatostatin, PP (pancreatic polypeptide) and GRF (growth hormone releasing factor), in addition to insulin, are produced in pancreatic islet cells; bombesin-related peptides are the main markers of pulmonary endocrine cells; calcitonin and CGRP (calcitonin gene-related peptide) occur in thyroid and extrathyroid C cells; ACTH and endorphins in anterior and intermediate lobe pituitary cells, alpha-MSH and CLIP (corticotropin-like intermediate lobe peptide) in intermediate lobe cells; met- and leu-enkephalins and related peptides in adrenal medullary and paraganglionic cells as well as in some gut (enterochromaffin) cells; NPY (neuropeptide Y) in adrenaline-type adrenal medullary cells, etc.. Both tissue-appropriate and tissue-inappropriate regulatory peptides are produced by endocrine tumours, with inappropriate peptides mostly produced by malignant tumours.

Animals↗
PubMed1987

Nervous tissue thiamine metabolism in vivo. III. Influence of ethanol intake on the dynamics of thiamine and its phosphoesters in different brain regions and sciatic nerve of the rat.

The effects of chronic ethanol administration on different steps of the metabolism of thiamine (T), thiamine mono- (TMP) and thiamine pyrophosphate (TPP) in the cerebellum, brainstem, cerebral cortex and sciatic nerve were evaluated in vivo. The radioactivity of T and its phosphoesters was determined in plasma and in the selected nervous structures under steady-state conditions and at fixed time intervals (0.5-192 h) after an i.p. injection of [14C]T (30 micrograms: 1.25 microCi) to rats chronically (35 days) ethanol-treated (daily dose of 4.7 g X kg-1 b.wt. by gastric gavage) and pair-fed controls similarly treated with a sucrose solution isoenergetic with ethanol. All rats were given a nutritionally adequate diet supplying an excess of thiamine, which produced a virtually steady content of thiamine compounds in the tissues. By using a compartmental mathematical model, fractional rate constants, turnover rates and turnover times were calculated. Ethanol caused a reduction of the rate of thiamine compound enzymatic transformations (T phosphorylation to TPP, TPP dephosphorylation to TMP and TMP to T), and a facilitation of the regional uptake of T and TMP, associated to a less relevant influence on their release. Isoenergetic sucrose prevailingly caused an increased rate of thiamine metabolic steps (except phosphorylation in the brainstem and cerebral cortex), with negligible modifications of T and TMP uptake and release. Thus the changes induced by ethanol were virtually opposite to those caused by sucrose.

Animals↗
PubMed1987

A mixed pattern of endocrine cells in metaplastic Barrett's oesophagus. Evidence that the epithelium derives from a pluripotential stem cell.

In order to characterize the differentiation of endocrine cells present in Barrett's oesophagus and to determine if they express a single or multiple hormonal pattern, endoscopic biopsies were taken from both the lesion and the fundus of 45 patients and studied at the light microscopical level. Conventional histology revealed three different epithelial patterns: gastric atrophic fundic, intestinal and junctional. A mixture of these patterns was present in 28 cases (62%) and the single type was identified in 17 cases (38%). The use of three silver staining methods and antibodies to human chromogranins allowed us to identify numerous endocrine cells in all but 1 case. Eleven sera against all the most common hormones stored in the endocrine cells of the gut were used to identify the main products of the cells. The following immunoreactivities were identified: 5-hydroxytryptamine (5-HT) (in 75% of the studied cases), somatostatin (87%), motilin (31%), pancreatic polypeptide (PP) (20%), glucose-dependent insulinotropic polypeptide (20%), gastrin (15%), glucagon (15%), peptide tyrosine tyrosine (13%), secretin (7%) and neurotensin (2%). No cholecystokinin-immunoreactive cells were identified. Our results indicated that, in Barrett's epithelium, both gastric and intestinal endocrine cells differentiate, in accordance with the variability of differentiation in the non-endocrine cells present in the different types of columnar epithelium. These findings provide support for the conclusion that Barrett's epithelium arises from a pluripotential stem cell capable of both gastric and intestinal differentiation.

Aged↗
PubMed1987

Glucagon, glicentin, proglucagon, PYY, PP and proPP-icosapeptide immunoreactivities of rectal carcinoid tumors and related non-tumor cells.

Glucagon/PP-related peptides were detected immunohistochemically in 18 out of 22 cases of rectal tumors investigated. The reactive tumors showed prevalence of trabecular or mixed trabecular-acinar structure and moderate staining with Grimelius' silver and lead-hematoxylin. Three of the remaining 4 cases were characterized by reactivity for 5-hydroxytryptamine only, prevalence of a solid nest structural component and intense staining with Grimelius' silver technique and lead-hematoxylin. Fifteen of the 18 glucagon/PP-reactive cases were investigated immunohistochemically with a series of 6 sera directed against different sequences of glucagon, glicentin and proglucagon, and of 7 sera directed against PP, PYY and proPP-icosapeptide. A large spectrum of glucagon-related immunoreactivities, including C-terminus and mid-portion glucagon-immunoreactivity, N- and C-terminus glicentin-immunoreactivity, GLP1- and GLP2-immunoreactivity, were detected in human rectal L cells and most rectal carcinoids. With the exception of a few scattered cells in the rectal mucosa and in 3 tumors, C-terminus glucagon-immunoreactivity was obtained only after trypsin or subtilisin treatment of tissue sections. Both PYY and PP/proPP-like peptide(s) were detected in rectal L cells and carcinoids, with prevalence of PYY in normal cells and PP/proPP-like peptides in tumor cells. It is concluded that the same or closely related hormone/prohormone sequences are synthesized and stored in rectal endocrine cells and carcinoid tumors although differences of quantitative expression, post-translational cleavage or reactivity to antibodies may occur. The usefulness of protease treatments of tissue sections to unmask immunoreactivities of uncleaved propeptides or fixative-denatured peptides is outlined.

Animals↗
PubMed1987

Synaptophysin immunoreactivity and small clear vesicles in neuroendocrine cells and related tumours.

Synaptophysin (protein p38) immunoreactivity has been detected immunohistochemically in neuroendocrine cells of the human adrenal medulla, carotid body, skin, pituitary, thyroid, lung, pancreas and gastrointestinal mucosa as well as in 87 out of 93 neuroendocrine tumours investigated, including pheochromocytomas, chromaffin and non-chromaffin paragangliomas, ganglioneuromas, pituitary adenomas, thyroid medullary carcinomas, parathyroid adenomas, lung carcinoids and neuroendocrine carcinomas, pancreatic and gut endocrine tumours and cutaneous merkelomas. Parallel ultrastructural investigation of synaptophysin-reactive cells and tumours revealed the presence, in addition to dense-cored, secretory granules, of a population of pleomorphic, small, clear vesicles resembling synaptic vesicles of nerve terminals as well as the synaptophysin immunoreactive vesicles already described in rat adrenal medullary and pituitary cells. Synaptophysin immunoreactivity showed several differences in its distribution among tumour and non-tumour endocrine cells when compared to chromogranin A immunoreactivity, a well known marker of the core of endocrine granules. Synaptophysin represents a reliable general marker of neuroendocrine cells and tumours, which may be useful in diagnostic histopathology.

Chromogranin A↗
PubMed1987

Mice transgenic for a vasopressin-SV40 hybrid oncogene develop tumors of the endocrine pancreas and the anterior pituitary. A possible model for human multiple endocrine neoplasia type 1.

The authors have used transgenic mice to study the activity of a hybrid oncogene made up of 1.25 kb of 5' upstream sequences, derived from the bovine vasopressin gene, promoting the expression of the large T-antigen coding sequences of the early region of simian virus 40. Rather than promoting tumorigenesis in vasopressinergic cells of the hypothalamus, expression and activity of the hybrid oncogene, and consequent tumor formation, were confined to insulin-producing beta cells of the endocrine pancreas and to cells in the anterior pituitary. These observations suggest that the specificity of vasopressin gene expression normally results from an interaction between several regulatory elements, some of which are absent from the hybrid oncogene. The possible relationship between the endocrine tumor syndrome found in the vasopressin-SV40 transgenic mice and familial human multiple endocrine neoplasia is discussed.

Adenoma, Islet Cell↗
PubMed1986

Effects of acute and chronic ethanol administration on regional thiamin pyrophosphokinase activity of the rat brain.

Thiamin pyrophosphokinase (TPKase) activity was determined in supernatants of cerebral cortex, cerebellum, pons, medulla, hypothalamus and corpus callosum homogenates obtained from normal rats and from rats given ethanol acutely (a single dose of 4.7 g X kg-1 body wt) or chronically (4.7 g X kg-1 body wt daily for 35 days) by gastric gavage. Regional cell densities (derived from DNA content) and protein contents were also determined. TPKase was detected in all brain regions investigated, the highest activity being found in the cerebellum or in the pons depending on whether it was expressed per mg of protein or per number of cells, respectively. In samples taken following acute ethanol administration protein content was unaffected, while TPKase activity was significantly reduced in the cerebellum, cerebral cortex and hypothalamus at 90 min and in the cerebellum and cerebral cortex at 300 min. Chronic ethanol intake was associated with a significant decrease in regional cell densities, protein contents and TPKase activity. The addition of ethanol to the incubation medium of normal tissue supernatant caused a dose-dependent inhibition of TPKase activity. These results suggest that ethanol markedly impairs thiamin cellular utilization, which may result in depression of brain metabolism.

Animals↗
PubMed1986

[Cerebral vasospasm. Clinical and experimental aspects].

A large number of experimental data suggest a possible biochemical hypothesis for the trigger stimulus of cerebral vasospasm after subarachnoid hemorrhage (SAH). Among several classes of possible spasmogens, arachidonic acid metabolites may play a primary role. Authors have measured with radioimmunoassay technique (R.I.A.) the levels of four arachidonate metabolites (PGD2, TxB2, 6-keto-PGF1 alpha and i-LTC4) in lumbar and cisternal cerebrospinal fluid (CSF) of patients admitted with diagnosis of aneurysmal SAH. In all cases a significant activation of arachidonate metabolism is found, if compared to control cases. Patients with demonstrated vasospasm have significantly higher CSF levels of PGD2 and i-LTC4. Cisternal CSF levels of four metabolites are significantly higher than lumbar CSF levels. This suggests the correlation between subarachnoidal clot extension and the risk for vasospasm. Authors also present an experimental animal model of SAH, which is reliable from a pathological standpoint. This model could be therefore used in the study of neurochemical and neuropharmacological aspects of SAH.

6-Ketoprostaglandin F1 alpha↗
PubMed1986

Chromogranin A, B and C immunoreactivities of mammalian endocrine cells. Distribution, distinction from costored hormones/prohormones and relationship with the argyrophil component of secretory granules.

Antibodies specific for chromogranin A, B or C have been used to detect immunohistochemically these three anionic proteins. Pancreatic A, B and PP cells, gut argentaffin EC, argyrophil ECL and gastrin G cells, thyroid C cells, parathyroid cells, adrenal medullary cells, pituitary TSH, FSH and LH cells as well as some axons of visceral nerves have been found to react with chromogranin A antibodies. Pancreatic A, gut EC and G, adrenal medullary and pituitary cells as well as some gut nerve fibers showed chromogranin B immunoreactivity. Chromogranin C immunoreactivity has been detected in pancreatic A, pyloric D1, intestinal L, thyroid C, adrenal medullary and pituitary cells, as well as in some gut neurons and nerve fibers. No crossreactivity has been found in immunohistochemical tests between chromogranins A, B or C and costored monoamines or peptide hormones/prohormones, from which chromogranins can be separated by selective extraction during fixation. On both morphological and chemical grounds a relationship seems to exist between chromogranin A and Grimelius' argyrophilia. Sialooligosaccharide chains of chromogranin A and, possibly, chromogranins' phosphoserine/phosphothreonine groups, seem to interact with guanidyl, amino, and/or imidazole groups of non-chromogranin components to form silver complexing sites accounting for granules' argyrophilia, which can be removed or blocked without affecting chromogranin immunoreactivities. The abundant anionic groups of the three proteins should contribute substantially to granules' basophilia, the partly "masked" pattern of which supports the existence of a close interaction of such groups with other components of secretory granules, including monoamines and peptide hormones or prohormones. Chromogranins could play a rôle in hormone postranslational biosynthesis and intragranular packaging.

Adrenal Medulla↗
PubMed1986

Venous saclike aneurysm of the central nervous system.

A case of cerebral venous saclike aneurysm of the parietal cerebral cortex is presented with surgical and histological confirmation. Computed tomographic findings are non-specific but very useful for detecting the lesion. Angiographic findings are not so obvious as with an arteriovenous malformation, but are necessary for the final diagnosis of a cerebral varix.

Female↗
PubMed1986

Gastric carcinoids and related endocrine growths.

A series of 30 gastric endocrine tumours has been revised in the light of available available cytologic and clinicopathologic information. Among 24 well differentiated endocrine tumours-16 with and 8 without chronic atrophic gastritis (CAG)-3 gastrin cell tumours have been distinguished from 21 argyrophil carcinoids, 15 of which showed light- and/or electronmicroscopy patterns of enterochromaffin-like (ECL) cell tumours, 2 of EC cell tumours and 1 of D1/P cell tumour. One case of mixed carcinoid/adenocarcinoma and 5 cases of endocrine carcinomas, 4 poorly and 1 moderately differentiated, were also identified. Achlorhydria, due to type A CAG or HCl-suppressing drugs, and bombesin hyperstimulation are among possible factors inducing G cell hyperfunction and/or hyperplasia. Hypergastrinaemia is among causative agents of argyrophil ECL cell hyperplasias and, possibly, of tumours of the oxynticopeptic mucosa, while chronic inflammation and gland atrophy with or without concomitant hypergastrinaemia are important factors in inducing both hyperplastic and tumour argyrophil growths in CAG mucosa.

Carcinoid Tumor↗
PubMed1986

Prevention of relapse with various antiulcer drugs.

The relative value of maintenance therapy with cimetidine, ranitidine, pirenzepine, and antacids only (when used for symptomatic relief) has been evaluated in 205 patients with a subsequent follow-up period of 2 years. The patients had a completely healed duodenal ulcer after 8 weeks of treatment and were then randomly allocated to four groups, which were as follows: group 1: 60 patients treated with 400 mg cimetidine at night; group 2: 55 patients treated with 150 mg ranitidine at night; group 3: 50 patients treated with 50 mg pirenzepine at night; and group 4: 40 patients treated only with antacids as needed for symptomatic relief. Endoscopy was repeated after 6, 12, 18, and 24 months of treatment, and whenever symptoms suggested recurrence. Although the number of dropouts was high (27 in group 1, 20 in group 2, 18 in group 3 and 12 in group 4), statistical analysis by the life-table method showed that cimetidine, ranitidine, and pirenzepine had similar therapeutic value. After 1 and 2 years the relapse rate of duodenal ulcer was 17.5% and 43.6% respectively, for cimetidine, 21% and 69.3% for ranitidine, 21.7 and 50.2% for pirenzepine, and 49.8% and 77.7% for antacids. The incidence of erosions was lower in those groups with the higher ulcer relapse rate, a point discussed in the present study.

Adult↗
PubMed1986

The effect of corticosteroids on microvillous vesicles from the small intestine of adult rats: an automated, morphometric analysis.

The hypothesis that the corticosterone-induced enhancement of D-glucose uptake by brush-border membrane vesicles from the small intestine of adult rats is caused by an alteration in vesicle volume was tested by means of structural morphometric computerized analysis. By using a Ca2+ precipitation method, microvillous membrane vesicles were prepared from different groups of adult rats: normal controls; animals sacrificed 8 days after adrenalectomy; sham-operated pair-fed controls; animals treated with corticosterone (1 or 10 mg x 100 g b.wt.-1 daily i.p. for 8 days); corticosterone vehicle-treated controls. The vesicles were processed by conventional electron microscopy techniques. Morphometric computerized analysis was carried out on electron micrographs at a 20,000 x magnification, after selecting by an interactive method the vesicles showing certain morphologic features. The morphometric parameters determined for the vesicles from each experimental group were diameter, shape factor (minimal to maximal diameter ratio), surface area and volume. The following main findings were obtained: the vesicles were consistently spherical, with the glycocalyx on the outer side; sham-operation and pair-feeding with adrenalectomized rats, as well as corticosterone-vehicle injection, significantly reduced vesicular volume as compared to normal controls; adrenalectomy significantly decreased vesicular volume as compared to pair-feeding; excess of corticosteroids caused opposite changes (i.e. a significant increase of vesicle volumes as compared to vehicle injection), which were apparently dose-dependent. A comparison with D-glucose vesicular transport data previously obtained under the same experimental conditions revealed the existence of a positive relationship between vesicular volume and D-glucose half-filling time (t 1/2). A positive relationship between vesicular volume and D-glucose vesicular space was found for all experimental conditions except vehicle injection. As a whole, the morphometric results were consistent with functional findings, supporting our previous hypothesis that the corticosterone-induced increase in D-glucose transport by small intestinal microvillous vesicles is due, at least in part, to enlargement of the vesicle.

Animals↗
PubMed1985

Ultrastructural localization of cholecystokinin in endocrine cells of the dog duodenum by the immunogold technique.

Cholecystokinin (CCK) has been localized by the immunogold technique in a type of endocrine cell of the dog duodenum characterized by small (166 +/- 38 nm) secretory granules with fairly dense, homogeneous core separated from its enveloping membrane by a thin clear space. The CCK cell is immunocytochemically distinct and cytologically different from other types of endocrine cells, as the secretin, GIP and motilin cells, already identified in the dog duodenum.

Animals↗
PubMed1985

Glucagon- and PP-related peptides of intestinal L cells and pancreatic/gastric A or PP cells. Possible interrelationships of peptides and cells during evolution, fetal development and tumor growth.

The immunohistochemical detection of six distinct sequences of proglucagon and its derivatives (GRPP, glicentin, glucagon-37, glucagon-29, GLP1, GLP2 and MPGF) in both intestinal L cells and pancreatic or gastric A cells of some mammals (dog, man, guinea pig) confirms that the two cell types produce the same proglucagon molecule, although the final step of its post-translational processing differs in the two cells. Immunohistochemical and ultrastructural patterns of glucagon/glicentin cells in the pancreas of lower vertebrates and early human fetuses, as well as tumor cell studies, suggest an evolution of gastropancreatic A cells from L cells. On the contrary, the PP-related peptide PYY of intestinal L cells, and PP with its C-terminal icosapeptide extension of pancreatic PP cells, likely originate from different prohormones. Although intermediate patterns of peptide expression can be observed, including some F-type PP cells of the dog pancreas (uncinate process) and pyloric mucosa showing PYY immunoreactivity or rare PYY and/or HPP immunoreactive cells of the human rectum lacking glicentin reactivity, no obvious relationship can be established between L cells and pancreatic (F-type) PP cells. However, some evolutionary, embryogenetic and oncogenetic link may exist between L cells and human D1-type PP cells, a minor population of PP cells scattered in the pancreatic tissue of dorsal pouch origin and a major fraction of tumor PP cells.

Animals↗
PubMed1985

Comparison between ranitidine and cimetidine in the short-term treatment of duodenal ulcer.

Two groups of 46 and 49 patients each with endoscopically proved duodenal ulcer and not previously treated, received ranitidine (150 mg X 2 daily) and cimetidine (1 g/day) respectively for eight weeks. The disappearance of the ulcer was observed endoscopically in 78% of both the first and second groups of patients. Of the ten patients non-responders to ranitidine, six were treated again for eight weeks with ranitidine and four with cimetidine for eight weeks; all of them recovered completely apart from one of the cimetidine treated patients. Of the 11 patients non-responders to cimetidine, seven were retreated with cimetidine and 4 with ranitidine for a further eight weeks and all of them obtained a complete recovery except for one of the cimetidine treated patients. No relevant side-effects were observed with either drug. In conclusion cimetidine and ranitidine showed a comparable therapeutic value.

Adult↗