Biomedical subjects

M Perego

Publications and source records attributed to M Perego.

At least 55 records · Page 3Linked to original sources

PubMed1996

Omeprazole coupled with two antibiotics for Helicobacter pylori eradication and prevention of ulcer recurrence.

BACKGROUND: Numerous therapeutic trials aimed at eradicating Helicobacter pylori (HP) from the gastric mucosa and preventing ulcer recurrence have been carried out; however, an optimal treatment has not yet been established with carefully controlled randomized studies. OBJECTIVE: The aim of our study was to evaluate the efficacy of an association of omeprazole (OM) coupled with two antibiotics in the eradication of HP and prevention of duodenal ulcer (DU) recurrence. METHODS: One hundred and eighty three patients with active DU were randomized under double-blind conditions to receive either OM 20 mg for 4 wk plus amoxycillin 3 g daily and metronidazole 1 g daily during the 2nd and 3rd wk (91 patients, group A) or OM 20 mg for 4 wk plus matching placebo (92 patients, group B). Endoscopy was performed before and at the end of the 4-wk treatment as well as 2, 6, and 12 months later. Biopsies were taken from the duodenum, antrum, and gastric body at each endoscopic examination for HP histological detection and for evaluation of inflammatory changes according to the Sydney system. RESULTS: After 4 wk, 84/86 patients (98%) of group A and 80/86 (93%) of group B were healed of their ulcers. The percentage of eradication was 90% in group A and 1% in group B. During a 12-month follow-up, DU relapsed in 4/63 (6%, including two of three reinfected cases) HP-eradicated group A patients, 4/8 (50%) HP-noneradicated group A patients, and 52/65 (80%) persistently HP-positive group B patients. Rapid, complete, and persistent suppression of gastroduodenitis activity and gastric surface epithelium lesions was observed in most HP-eradicated group A patients, whereas a transient decrease of bacterial colonization and inflammatory scores in the antrum and a transient worsening of corpus gastritis were found in group B patients. CONCLUSIONS: The combined therapy with amoxycillin, metronidazole, and omeprazole is highly effective in both HP eradication and prevention of duodenal ulcer recurrence.

Adult↗

PubMed1995

Incorporation of D-alanine into lipoteichoic acid and wall teichoic acid in Bacillus subtilis. Identification of genes and regulation.

The Bacillus subtilis dlt operon (D-alanyl-lipoteichoic acid) is responsible for D-alanine esterification of both lipoteichoic acid (LTA) and wall teichoic acid (WTA). The dlt operon contains five genes, dltA-dltE. Insertional inactivation of dltA-dltD results in complete absence of D-alanine from both LTA and WTA. Based on protein sequence similarity with the Lactobacillus casei dlt gene products (Heaton, M. P., and Neuhaus, F. C. (1992) J. Bacteriol. 174, 4707-4717), we propose that dltA encodes the D-alanine-D-alanyl carrier protein ligase (Dcl) and dltC the D-alanyl carrier protein (Dcp). We further hypothesize that the products of dltB and dltD are concerned with the transport of activated D-alanine through the membrane and the final incorporation of D-alanine into LTA. The hydropathy profiles of the dltB and dltD gene products suggest a transmembrane location for the former and an amino-terminal signal peptide for the latter. The incorporation of D-alanine into LTA and WTA did not separate in any of the mutants studied which indicates that either one and the same enzyme is responsible for D-alanine incorporation into both polymers or a separate enzyme, encoded outside the dlt operon, transfers the D-alanyl residues from LTA to WTA (Haas, R., Koch, H.-U., and Fischer, W. (1984) FEMS Microbiol. Lett. 21, 27-31). Inactivation of dltE has no effect on D-alanine ester content of both LTA and WTA, and at present we cannot propose any function for its gene product. Transcription analysis shows that the dlt operon is transcribed from a sigma D-dependent promoter and follows the pattern of transcription of genes belonging to the sigma D regulon. However, the turn off of transcription observed before sporulation starts seems to be dependent on the Spo0A and AbrB sporulation proteins and results in a D-alanine-free purely anionic LTA in the spore membrane. The dlt operon is dispensable for cell growth; its inactivation does not affect cell growth or morphology as described for L. casei.

Alanine↗

PubMed1995

Effect of anticonvulsant drugs on peripheral benzodiazepine receptors of human lymphocytes.

Anticonvulsant drugs, such as carbamazepine, may exert some of their effects through peripheral benzodiazepine receptors (PBR), which are present in glial cells and regulate the synthesis of neurosteroids. PBR have also been demonstrated in human lymphocytes, where they might be used as peripheral markers of anticonvulsant drug effects. In the present paper we investigated the interaction of various antiepileptic drugs with PBR of human lymphocytes and evaluated possible effects of acute and chronic treatment with these drugs. At normal therapeutic concentrations, diazepam, carbamazepine and phenobarbital occupy respectively 70, 30 and 10% of PBR sites in human lymphocytes. Although no change of receptor density or affinity was observed after acute in vitro treatment, in epileptic patients chronically treated with carbamazepine, phenobarbital and valproic acid, PBR Bmax was increased with respect to controls and untreated epileptics. Since PBR of human lymphocytes may be affected by anticonvulsant drug treatment, we suggest that they might be involved in the immunological alterations reported in these patients and might be used as peripheral markers of drug effects on the central nervous system.

Adolescent↗

PubMed1995

Proglumide, a cholecystokinin receptor antagonist, reduces neuroleptic action in Huntington's chorea.

In a pilot study, proglumide, a cholecystokinin receptor antagonist, was administered to 8 patients affected from Huntington's chorea under long-term haloperidol treatment. The effectiveness of haloperidol on chronic symptomatology was reduced by the concomitant administration of proglumide; the latter drug, when administered alone, did not modify the severity of chorea compared to placebo. Possible explanations of these results are discussed, stressing the modulatory role of CCK not only on the dopaminergic, but also on the GABAergic system.

Adolescent↗

PubMed1994

Multiple protein-aspartate phosphatases provide a mechanism for the integration of diverse signals in the control of development in B. subtilis.

The initiation of sporulation in B. subtilis is regulated by the Spo0A transcription factor, which is activated by phosphorylation to control developmental switching from the vegetative to the sporulation state. The level of phosphorylation of Spo0A is regulated by the phosphorelay, a signal transduction system based on the protein-histidine kinase-response regulator two-component paradigm. To initiate sporulation, the cell must recognize and interpret a large variety of environmental, metabolic, and cell cycle signals that influence the phosphorylation level of Spo0A. We describe here a family of protein-aspartate phosphatases with activity on Spo0F approximately P, a response regulator component of the phosphorelay, that provide a mechanism for signal recognition and interpretation. These phosphatases function to drain the phosphorelay, lower Spo0A approximately P levels, and prevent sporulation. The integration of diverse environmental signals that affect the initiation of sporulation likely occurs through the competition between opposing activities of protein kinases and protein phosphatases.

Amino Acid Sequence↗

PubMed1994

Effects of eradication of Helicobacter pylori on gastritis in duodenal ulcer patients.

The incidence and mean score of Helicobacter pylori-related, active antroduodenitis, lesions of superficial antral epithelium and duodenal gastric-type metaplasia were higher in endoscopic biopsies from a large series of patients with duodenal ulcer, when compared with asymptomatic patients or patients with non-ulcer dyspepsia. In 65 out of 73 patients with duodenal ulcer who could be followed up, H. pylori was eradicated using a combination of amoxycillin, 3 g daily, metronidazole, 1 g daily, and omeprazole, 20 mg daily. Rapid and permanent (6-month follow-up) abolition of both gastroduodenitis activity and lesions of the gastric surface epithelium was observed in these 65 patients. There was also a progressive decrease in total immune-inflammatory cells but without a substantial change in duodenal gastric-type metaplasia. Similar, but transient and quantitatively less prominent, improvements were observed in the antroduodenal mucosa, which had been temporarily cleared of H. pylori by treatment with omeprazole alone. Conversely, increased gastritis activity, epithelial lesions and immune-inflammatory cell scores were found in the short term in the corpus mucosa, which was not cleared of H. pylori after omeprazole treatment. It is concluded that, of the various H. pylori-related mucosal changes, antroduodenitis activity and antral epithelial lesions most closely reflect the severity of mucosal damage and are probably the most important factors in duodenal ulcerogenesis. Their complete and rapid suppression after bacterial eradication may be a key factor in preventing ulcer relapse.

Amoxicillin↗

PubMed1993

Glutamate synthase genes of the diazotroph Azospirillum brasilense. Cloning, sequencing, and analysis of functional domains.

A 10-kilobase EcoRI fragment of Azospirillum brasilense genomic DNA was cloned in Escherichia coli. Two open reading frames of 4548 and 1446 base pairs (bp) were identified within the fragment as the structural genes for the alpha and beta subunits (gltB and gltD, respectively) of A. brasilense GltS. The organization of the gltBD region of A. brasilense differs from that of the corresponding region in E. coli: in A. brasilense, gltD is upstream relative to gltB, and its stop codon is separated by 141 bp from the first ATG of gltB. The deduced amino acid sequences reveal a high similarity with GltS from E. coli and with the ferredoxin-dependent GltS from maize. Binding domains for flavin cofactors and NADPH, a domain for glutamine binding and activation, and cysteine clusters for iron-sulfur centers formation were tentatively identified on the basis of sequence comparison with flavoproteins, pyridine nucleotide-dependent enzymes, amidotransferases, and iron-sulfur proteins.

Amino Acid Sequence↗

PubMed1993

Benzodiazepine receptors and diazepam binding inhibitor: a possible link between stress, anxiety and the immune system.

This review summarizes the evidence available on the involvement in stress of different classes of benzodiazepine receptors and their putative endogenous ligand, diazepam binding inhibitor (DBI), with particular reference to their role in modifications of the immune response. The presented data from in vitro, experimental, and clinical studies suggest that benzodiazepine receptors and DBI play a major role in regulating steroid production in both the adrenals and central nervous system, and may be involved in the activation of the hypothalamic-pituitary-adrenal axis in stress response.

Animals↗

PubMed1993

Sequence and analysis of the genetic locus responsible for surfactin synthesis in Bacillus subtilis.

The chromosomal region of Bacillus subtilis comprising the entire srfA operon, sfp and about four kilobases in between have been completely sequenced and functionally characterized. The srfA gene codes for three large subunits of surfactin synthetase, 402, 401 and 144 kDa, respectively, arranged in a series of seven amino acid activating domains which, as shown in the accompanying communication, recognize and bind the seven amino acids of the surfactin peptide. The srfA amino acid activating domains share homologies with similar domains of other peptide synthetases; in particular, regions can be identified which are more homologous in domains activating the same amino acid. A fourth gene in srfA encodes a polypeptide homologous to grsT. Four genes are positioned between srfA and sfp, the disruption of which does not affect surfactin biosynthesis.

Amino Acid Isomerases↗

PubMed1992

Neuroimmunotherapy with subcutaneous low-dose interleukin-2 and the pineal hormone melatonin as a second-line treatment in metastatic colorectal carcinoma.

On the basis of our previous preliminary data which showed that the pineal hormone melatonin (MLT) may potentiate IL-2 activity and reduce the dose of IL-2 required to determine an effective host antitumor response, we performed a clinical study with low-dose IL-2 given once/day subcutaneously (3 million IU/day for 6 days/week for 4 weeks) in association with MLT (50 mg/day orally at 8.00 p.m. every day) as a second-line therapy in metastatic colorectal cancer patients pretreated with 5-fluorouracil. Evaluable patients were 13/14, and most of them showed disseminated liver metastases. No objective tumor regression was seen. A stabilization of disease was achieved in 4/13 patients (median duration 5+ months), and the other 9 patients progressed. Mean number of lymphocytes and eosinophils significantly increased during the treatment. Moreover, the mean increase in lymphocyte number was significantly higher in patients with stable disease than in those with progressive disease, whereas there was no difference as regards eosinophils. Serum levels of neopterin and tumor necrosis factor (TNF) significantly increased during therapy, and TNF increase was correlated to the side effects rather than to the control of cancer development. This study shows that neuroimmunotherapy with low-dose interleukin-2 and MLT, even though capable of determining an evident expansion of immune cells involved in host antitumor response, does not seem to be effective in terms of tumor regression in metastatic colon cancer patients pretreated with 5-fluorouracil.

Adult↗

PubMed1992

Helicobacter colonization and histopathological profile of chronic gastritis in patients with or without dyspepsia, mucosal erosion and peptic ulcer: a morphological approach to the study of ulcerogenesis in man.

Helicobacter pylori colonization and the incidence, severity, activity and topography of gastritis were investigated systematically in antrum and corpus mucosal biopsies of 1177 subjects undergoing endoscopy in the absence of gastric complaints (asymptomatic, 49) or for non-ulcer dyspepsia (NUD; 631 patients, 72 of whom had gastric and/or duodenal erosions), active gastric ulcer (GU, 76 patients), active duodenal ulcer (DU, 138 patients), and healed gastric (HGU, 39 cases) or duodenal ulcer (HDU, 230 cases). In the antrum, H. pylori colonization and the incidence, severity and activity of gastritis increased progressively in the sequence asymptomatic, erosion-free NUD, erosive NUD, healed ulcer and active ulcer. The same trend was observed in the corpus as regards H. pylori and gastritis incidence, whereas the severity and activity of gastritis were lower in active DU and erosive NUD and higher in active, proximal GU than in the remaining patients. Active DU and erosive NUD showed the highest incidence of non-atrophic gastritis and lowest type-A or AB atrophic gastritis, while active GU had lowest normal mucosa or type-A gastritis and highest type-B atrophic gastritis. In conclusion, H. pylori colonization and gastritis incidence, severity and, especially, activity of the antrum might all contribute to mucosal erosion and ulceration, whereas the same factors, at least in part and with the exception of proximal GU, seem to have a preventive role when affecting corpus mucosa.

Adolescent↗

PubMed1992

Enhanced secretion of tumour necrosis factor in patients with myocardial infarction.

OBJECTIVES: Recent evidence suggests that leukocyte infiltration of myocardial tissue may extend the area of necrosis during the acute phase of myocardial infarction. Since the activation of leukocytes depends on the action of cytokines, mainly tumour necrosis factor (TNF), we evaluated TNF secretion during myocardial infarction. METHODS: The study included 12 patients with acute myocardial infarction as diagnosed on the basis of enzymatic and ECG criteria. Patients were admitted within 3 hours from onset of chest pain. Serum levels of TNF were measured by immunoradiometric assay on venous blood samples collected at time 0, and at 6, 12 and 18 hours and 1, 2, 4 and 7 days following myocardial infarction. Plasma levels of atrial natriuretic peptide-alpha (ANP) were also measured on the same samples. RESULTS: Mean TNF levels significantly increased during the myocardial infarction, with a peak within the first 24 hours (p < 0.01). They remained significantly elevated until day 4 (p < 0.05). The rise in TNF was positively correlated with creatinine kinase levels. ANP was also significantly increased with a delayed peak after that of TNF (p < 0.01). CONCLUSION: Even though limited to a small number of cases, this study shows that acute myocardial infarction is associated with increased TNF secretion. Because of its capacity of stimulating leukocyte infiltration in myocardial tissue, the increased levels of TNF might potentially have a negative prognostic significance.

Aged↗

PubMed1991

Increase in soluble interleukin-2 receptor and neopterin serum levels during immunotherapy of cancer with interleukin-2.

Both immunostimulatory and immunosuppressive events would occur during the immunotherapies of cancer, including interleukin 2 (IL-2) therapy. The marked increase in soluble IL-2 receptor (SIL-2R) levels during IL-2 therapy could represent a potentially negative biological effect, because of the receptor's capacity to bind IL-2 and compete for it with IL-2 cell surface receptor. Since it has been observed that macrophages stimulate in vitro the release of SIL-2R, a study was started to evaluate in vivo the role of macrophages in IL-2-induced SIL-2R rise by measuring neopterin, which is a marker of macrophage activity. The study included 9 advanced renal cancer patients, treated subcutaneously with IL-2 at 1.8 x 10(6) IU/m2 twice daily for 5 days/week for 6 weeks. Both SIL-2R and neopterin serum mean levels significantly increased during IL-2 treatment, and the highest concentrations were reached on the second week of therapy. SIL-2R rise was significantly correlated to that of neopterin. This study, by showing a positive correlation between SIL-2R and neopterin rise, would suggest a macrophage involvement in the stimulation of SIL-2R release during IL-2 immunotherapy of cancer.

Adenocarcinoma↗

PubMed1991

Mutational dissociation of the positive and negative regulatory properties of the Spo0A sporulation transcription factor of Bacillus subtilis.

The Spo0A regulatory protein controls the onset of stationary phase and sporulation by controlling transcription in both a negative and a positive manner depending on the promoter affected. Missense mutations, e.g., spo0A9V, which result in alterations in the eleventh amino acid preceding the C terminus of the Spo0A protein, give rise to a protein active as a negative regulator of the abrB gene but unable to activate transcription of the spoIIA gene. Second-site suppressors of spo0A9V occurred within the spo0A gene at codons 162 and 174. These suppressors did not suppress a spo0F mutation, indicating that the suppressed protein still requires phosphorylation for activity. The results suggest that the C terminus of Spo0A interacts with the transcription complex to activate transcription.

Amino Acid Sequence↗

PubMed1991

The oligopeptide transport system of Bacillus subtilis plays a role in the initiation of sporulation.

Bacillus subtilis spo0K mutants are blocked at the first step in sporulation. The spo0K strain was found to contain two mutations: one was linked to the trpS locus, and the other was elsewhere on the chromosome. The mutation linked to trpS was responsible for the sporulation defect (spo-). The unlinked mutation enhanced this sporulation deficiency but had no phenotype on its own. The spo- mutation was located in an operon of five genes highly homologous to the oligopeptide transport (Opp) system of Gram-negative species. Studies with toxic peptide analogues showed that this operon does indeed encode a peptide-transport system. However, unlike the Opp system of Salmonella typhimurium, one of the two ATP-binding proteins, OppF, was not required for peptide transport or for sporulation. The OppA peptide-binding protein, which is periplasmically located in Gram-negative species, has a signal sequence characteristic of lipoproteins with an amino-terminal lipo-amino acid anchor. Cellular location studies revealed that OppA was associated with the cell during exponential growth, but was released into the medium in stationary phase. A major role of the Opp system in Gram-negative bacteria is the recycling of cell-wall peptides as they are released from the growing peptidoglycan. We postulate that the accumulation of such peptides may play a signalling role in the initiation of sporulation, and that the sporulation defect in opp mutants results from an inability to transport these peptides.

Amino Acid Sequence↗

PubMed1991

Negative regulation of Bacillus subtilis sporulation by the spo0E gene product.

Transcription of the Bacillus subtilis spo0E gene is controlled by the AbrB transition state regulator. In AbrB+ strains, a single transcript, P1, was observed for the spo0E gene. In an abrB4 mutant strain, a second transcription start site 3 bases upstream from P1 was found to be used for the predominant transcript. P1 transcription was insensitive to the state of the abrB gene. Mutants carrying deletion or antibiotic cassette insertion mutations in the spo0E gene were Spo+. Multiple copies of the spo0E gene, not just the promoter region, were found to render strains incapable of sporulation. Spo+ strains that arose spontaneously from such Spo- strains were found to have deletions in the spo0E coding sequence on the plasmid. Strains carrying a deletion of the spo0E gene segregated Spo- colonies. These colonies were found to have secondary mutations in or near the spo0A, spo0B, or spo0F gene, suggesting that deletion of the spo0E gene results in increased pressure to sporulate that is compensated for by inactivation of one or more of the components of the signal transduction system leading to the initiation of sporulation. spo0E deletions were suppressors of the spo0F221 missense mutation but had no effect on the regulation of the spo0F, kinA, spo0A, or spo0B genes. The results suggest that the spo0E gene product is a negative regulator of the signal transduction pathway leading to sporulation.

Bacillus subtilis↗

PubMed1990

Evaluation of the cardiovascular toxicity related to cancer immunotherapy with interleukin-2 by monitoring atrial natriuretic peptide secretion: a case report.

Increased capillary permeability and severe hypotension represent the two major cardiovascular complications of IL-2 immunotherapy. The mechanisms responsible for IL-2 cardiovascular toxicity are still obscure. Since increased vascular permeability and vasodilatation may be also induced by the cardiac hormone atrial natriuretic peptide (ANP), we have evaluated ANP concentrations in relation to mean arterial pressure in one patient with metastatic renal carcinoma, treated with a 24-h intravenous infusion of IL-2 at a dose of 3 x 10(6) Cetus U/m2/day for 5 days. The results showed that episodes of important hypotension were associated with abnormally high plasma levels of ANP. Owing to its vasodilator activity, exaggerated ANP secretion, perhaps due to an inappropriate cardiac endocrine function in response to hemodynamic changes induced by IL-2, may play a role in hypotension, which occurs during IL-2 immunotherapy for cancer.

Atrial Natriuretic Factor↗

PubMed1990

Characterization of peripheral benzodiazepine receptors in human blood mononuclear cells.

In the present study, peripheral-type benzodiazepine receptors in human circulating mononuclear cells were characterized, using [3H]PK 11195 as specific ligand. The specific binding was saturable, with a Bmax of 14 pmol/mg protein and a Kd of 7 nM. The pharmacological characterization, using different displacing drugs, indicated a mitochondrial type of peripheral benzodiazepine receptor since it was not coupled to the GABA receptor and was displaced by protoporphyrin IX. These data indicate that human circulating mononuclear cells possess benzodiazepine recognition sites, similar to non-neuronal receptors. The role of these receptors and possible modifications in different diseases need to be investigated.

Adult↗