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L de Magistris

Publications and source records attributed to L de Magistris.

At least 19 recordsLinked to original sources
PubMed2001

Intestinal permeability in Crohn's disease patients and their first degree relatives.

BACKGROUND: Family studies suggested that an altered intestinal permeability plays a role in the genesis of Crohn's disease. AIM: Aim of the present study was to investigate a possible genetic alteration of the mucosal barrier in Crohn's disease. SUBJECTS: 16 Crohn's disease patients and 26 of their cohabiting first degree relatives were studied. METHODS: To investigate intestinal permeability, Cellobiose/Mannitol test was administered to both groups. RESULTS: In the two groups, we found that the median intestinal permeability values were higher and statistically different from those obtained in 32 healthy control subjects as well as in five healthy control families. Six (37.5%) Crohn's disease patients and three (11.5%) of their first degree relatives showed increased individual intestinal permeability values. Intestinal permeability alteration in Crohn's disease patients was unrelated to sex, age, disease activity, localisation, duration, treatment schedule, as well as to serum anti-Saccharomyces cervisiae antibody positivity in a pilot study conducted in 7 Crohn's disease patients; anti-Saccharomyces cervisiae antibody values were negative in all 10 first degree relatives investigated. CONCLUSIONS: These findings demonstrate the increase in IP in 37% of the patients and in 11% of their relatives. More extensive investigation of the correlation between ASCA alterations and IP will be needed in both patients with Crohn's disease and their relatives.

Adult↗
PubMed1999

Altered intestinal permeability to mannitol in diabetes mellitus type I.

BACKGROUND: Intestinal permeability has seldom been investigated in diabetes mellitus, even though patients frequently report gastrointestinal symptoms, and it has recently been shown that the prevalence of celiac disease associated with diabetes mellitus is higher than expected. METHODS: Intestinal permeability to cellobiose and mannitol was investigated in 31 patients affected by type I uncomplicated diabetes mellitus. Values were compared with those obtained in 32 normal subjects. RESULTS: The percentage of mannitol recovery was far higher than normal in two thirds of the investigated patients and correlated with the length of disease, even though the probes' ratio (cellobiose/mannitol) was in the normal range. CONCLUSIONS: A not previously reported increase of intestinal permeability to mannitol, clear-cut and not associated with that of the larger probe, is found in type I uncomplicated diabetes mellitus. These results may describe a primary feature of type I diabetes mellitus and the initial steps of evolution to celiac disease.

Adolescent↗
PubMed1999

Intestinal permeability and diabetes mellitus type 2.

BACKGROUND: Intestinal permeability can be investigated by means of molecular probes which are able to cross the intestinal wall through tight junctions of villi (smaller probes) and/or of crypts (larger probes). Intestinal permeability is altered in the majority of uncomplicated diabetes mellitus type 1 patients, due to the augmented absorption of the smaller probe. The aim of this work was to investigate if any similar alteration of intestinal permeability is present in diabetes mellitus type 2. METHODS: Intestinal permeability was studied by means of the Cellobiose/Mannitol test (CE/MA). The first and larger probe (Cellobiose) crosses tight junctions of crypts, the smaller (Mannitol) crosses those of villi. The CE/MA test was administered to 18 patients affected by diabetes mellitus type 2, with length of disease = 4.5+/-1.9 years (mean+/-SD) with no relevant intestinal pathologies. Results obtained in these 18 patients were compared with those of 25 healthy volunteers. RESULTS: Intestinal permeability to the CE/MA test was normal in all patients. All the investigated permeability parameters (%CE, %MA, CE/MA) overlapped, as a mean, with those of control subjects and were not statistically different. CONCLUSIONS: The present data confirm that diabetes mellitus type 2 has not pathophysiological components at intestinal level. This is different from what was demonstrated in diabetes mellitus type 1, the last being very well known to be associated with autoimmune diseases and celiac disease.

Journal Article↗
PubMed1990

A major thyroid hormone response element in the third intron of the rat growth hormone gene.

The rat growth hormone (RGH) gene constitutes a well-documented model system for the direct regulation of transcription by thyroid hormones. In order to analyse its interaction with sequences in the RGH gene, we have overproduced the thyroid hormone receptor-alpha (c-erbA) protein using a vaccinia virus expression system. The expressed protein bound T3 and DNA-cellulose with expected affinities, and the major binding site for the receptor protein was found to be located in the third intron of the RGH gene. This site displayed significantly higher affinity for the receptor protein than a previously described thyroid hormone response element (TRE) in the promoter of this gene, and also conferred stronger hormone responsiveness in vivo to a heterologous promoter. The data suggest that this novel TRE plays a major role in the regulation of rat growth hormone gene expression by thyroid hormones.

Animals↗
PubMed1990

Medical treatment of antral gastrin cell hyperfunction: role of nonantisecretory therapy.

Antral G cell hyperfunction (AGCH) is a rare condition, often associated with severe duodenal ulcer disease poorly responsive to medical therapy. Up to now, no studies have been designed to investigate a possible role of medical treatment in the management of this syndrome. In this study we treated 9 AGCH patients with duodenal ulcer, unhealed with the prolonging standard doses of H2 antagonists (300 mg/day ranitidine or 800 mg/day cimetidine), with a nonantacid therapy, tripotassium dicitrato bismuthate (TDB). 6 out of 9 patients showed a complete healing after 8 weeks of treatment. The healing was irrespective to eradication of Campylobacter pylori. After 9 weeks' suspension of H2 blockers basal gastrin levels decreased significantly by 31.5%, whereas peak meal-stimulated levels, although decreased in 6 out 9 patients, were not significantly affected by the withdrawal of the H2 antagonists. Nonantisecretory therapy seems to be an efficacious alternative in the management of AGCH patients.

Adolescent↗
PubMed1988

Cis-acting sequences affecting the length of the poly(A) head of vaccinia virus late transcripts.

Mutations in the sequences flanking the conserved and essential TAAAT motif of vaccinia late gene promoters (consensus: T/A T/A TAAAT G Pu Pu) affect the level of expression. Introduction of a pyrimidine in the purine stretch downstream of the TAAAT motif reduces the level of RNA synthesis. Mature transcripts from the wild-type 11K late promoter have a non-contiguous 5' poly(A) leader of approximately 35 A-residues (referred to as a poly(A) head). We show here by RNA sequencing, primer extension and subsequent m7G cap selection of cDNA/RNA hybrids that the mutations affect the length of the poly(A) head but not the location of the junction between the poly(A) leader and sequences encoded in the genome. These results are consistent with a slippage mechanism underlying the process of 5' poly(A) addition, but are not in agreement with a splicing event.

Base Sequence↗
PubMed1987

Dose-response effect of somatostatin-14 on human basal pancreatic hormones.

The effect of increased doses of Somatostatin-14 (3, 10, 30, 100, 300 micrograms/h) on basal release of insulin, pancreatic glucagon and pancreatic polypeptide (PP) was investigated on eight normal volunteers. Levels of Somatostatin-like immunoreactivity (SLI) was determined in order to correlate the increased SLI levels with the degree of islet hormone inhibition (r = 0.9947, p less than 0.01). By increasing the basal levels of SLI by one-third, a significant inhibition (p less than 0.01) of insulin, glucagon, and PP was noted (78.5, 78.6, 75.2%, respectively, on basal levels). The maximal effect was obtained with 300 micrograms/h for insulin, with 30 micrograms/h for glucagon and 100 micrograms/h for PP. In evaluating the relative inhibitory potency of somatostatin, expressed as ED50, the theoretic potency of somatostatin on each peptide had similar values, ranging from 30 to 10 micrograms/h. The present data show that a minimal peripheric increase in SLI is able to regulate basal islet pancreatic hormones.

Adult↗
PubMed1985

Evidence that bombesin releases extragastric gastrin in man.

Bombesin-induced gastrin release from extragastric sources has been investigated in two groups of patients without gastric antrum: 11 patients with total gastrectomy and 11 patients with subtotal (Billroth II) gastrectomy. A 30-min bombesin infusion (5 ng . kg-1 . min-1) caused a prompt significant gastrin increase (P less than 0.05) in both groups of patients. The gastrin response to bombesin was significantly (P less than 0.005) lower in patients without antral tissue than in the control group (n = 7). The individual peak gastrin responses, in totally (TG) and subtotally (SG) gastrectomized patients, were significantly over basal levels (TG: peak 100.3 +/- 12 vs. basal 62.8 +/- 9.1, P less than 0.005; SG: peak 96.9 +/- 9.4 vs. basal 72.4 +/- 6.8, P less than 0.001; pg/ml, mean +/- S.E.M.). These data indicate that bombesin acts not only on antral G cells, but on all gastrin cells in the gastrointestinal tract.

Adult↗
PubMed1985

Bombesin effects on human GI functions.

In this article some of the actions of amphibian skin peptide Bombesin (BBS) on human gastrointestinal and pancreatic functions are reviewed. BBS causes increases of lower esophageal sphincter pressure, delay of gastric emptying, inhibition of mechanical activity of duodenum and jejunum and gallbladder emptying. BBS also releases in man gastrin and stimulates gastric acid secretion. BBS administration induces release of insulin, glucagon and pancreatic polypeptide from human Islet of Langerhans and causes secretion of pancreatic bicarbonates and enzymes in duodenal juice and release of pancreatic enzymes in blood stream.

Bombesin↗
PubMed1985

Peptides of the APUD system in amphibian skins.

Methanol extracted skins from 84 species of amphibia were screened, measuring by RIAs: gastrin-CCK, VIP, calcitonin, GIP, PP and motilin. G-CCK-like immunoreactivity was found in 97.6%; VIP-like immunoreactivity in 41%; CT-like immunoreactivity in 34%; GIP-like immunoreactivity in 10%; PP-like immunoreactivity in 40% and MT-like immunoreactivity in 60% of the samples. The use of a sequence-specific radioimmunoassay and of gel-chromatography confirmed the caerulein-CCK-8-like nature of the immunoreactive material. Detected amounts of the other peptides (VIP, CT, GIP, PP, MT) were too low for bioassay or chromatographic studies, thus leaving the question open if they are due to some kind of unspecific interferences or, most likely, to species-specificity differences of the used antisera.

APUD Cells↗
PubMed1983

Effect of bombesin on plasma insulin, pancreatic glucagon, and gut glucagon in man.

The effect of bombesin on insulin, pancreatic glucagon, and gut glucagon was investigated in eight healthy volunteers and two pancreatectomized patients. Bombesin, infused iv at the constant rate of 5 ng kg-1 min-1, produced a sharp and statistically significant rise in the plasma insulin concentration. The peak was reached at 5 min (26 +/- 2.17 microU/ml; P less than 0.005 vs. basal values), followed by a prolonged and statistically significant (P less than 0.05) decrease in blood glucose. Pancreatic glucagon rapidly rose to a maximal value of 80.5 +/- 7.6 pmol/liter (P less than 0.005 vs. basal values). In contrast with the prompt increase in insulin and glucagon plasma levels, the peak in gut glucagon concentration (55.8 +/- 4.6 pmol/liter; P less than 0.005 vs. basal values) was reached 30 min after bombesin infusion was discontinued. In the two pancreatectomized patients, bombesin induced an increase in gut glucagon concentrations only. The results presented indicate that bombesin acts directly on the A and B cells of the pancreas, influencing glucose homeostasis; however, more complex mechanisms seem to be involved in gut glucagon secretion.

Adult↗
PubMed1982

Effect of bombesin on lower esophageal sphincter pressure in humans.

Intravenous infusion of bombesin in humans results in increased serum gastrin levels and increased lower esophageal sphincter pressure. To differentiate a gastrin- from a nongastrin-mediated mechanism, the effect of intravenous bombesin infusion on lower esophageal sphincter pressure was studied in 5 healthy subjects and in 5 antrectomized patients. Lower esophageal sphincter pressure was recorded by three continuously perfused catheters with side-openings located 5 mm apart. Blood samples were taken at regular intervals during the study periods to assay gastrin and pancreatic polypeptide. Manometric tracings and blood samples were coded and evaluated blindly. Lower esophageal sphincter pressure increased during bombesin infusion both in normal and antrectomized subjects. The increase had a delayed onset and persisted after discontinuation of bombesin. No correlation was found between lower esophageal sphincter pressure and serum gastrin or pancreatic polypeptide values. These data indicate that the effect of bombesin on lower esophageal sphincter pressure is not gastrin or pancreatic polypeptide mediated.

Adult↗
PubMed1981

Sulfation of gastrin: effect on immunoreactivity.

The effect of sulfuric acid esterification of Tyr-12 in gastrin-17 on immunoreactivity was evaluated by the ability of seventeen antisera raised against non-sulfated gastrin-17 to bind sulfated gastrins in extracts of gastrinoma and antral tissue. Using non-sulfated Tyr-12 iodinated gastrin as tracer, and non-sulfated gastrin-17 as standard the antisera showed three different patterns of reactivity: Three antisera (Nos. 2602, 2605 and 4562) bound sulfated gastrins with low (4-23%) potency; four antisera (Nos. 2604, 2720, 4710 and 4713) measured sulfated gastrins with a potency similar to that of non-sulfated gastrins (81-100% crossreactivity); whereas ten antisera (Nos. 2601, 2606, 2609, 2716, 2717, 2718, 4556, 4559, 4560 and 4563) displayed enhanced reactivity with sulfated gastrins (130-373% crossreactivity). Using Gly-2 iodinated gastrin as tracer, the latter type of antisera reacted almost equally with sulfated and non-sulfated gastrins, suggesting that the apparent increase in binding of sulfated gastrins rather is due to increased displacement of Tyr-12 iodinated gastrin. The results show that derivatization of amino acid residues greatly influences antibody binding.

Animals↗