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M Marino

Publications and source records attributed to M Marino.

At least 91 records · Page 5Linked to original sources
PubMed1998

ADP-ribose gates the fertilization channel in ascidian oocytes.

We report an ion channel in the plasma membrane of unfertilized oocytes of the ascidian Ciona intestinalis that is directly gated by the second messenger ADP-ribose. The ion channel is permeable to Ca2+ and Na+ and is characterized by a reversal potential between 0 and +20 mV and a unitary conductance of 140 pS. Preinjection of the Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) or antagonists of intracellular Ca2+ release channels into oocytes did not inhibit the ADP-ribose current, demonstrating that the channel is activated in a Ca2+-independent manner. Both the fertilization current and the current induced by the injection of nicotinamide nucleotides are blocked by nicotinamide, suggesting that the ADP-ribose channel is activated at fertilization in a nicotinamide-sensitive manner. These data suggest that ascidian sperm trigger the hydrolysis of nicotinamide nucleotides in the oocyte to ADP-ribose and that this mechanism is responsible for the production of the fertilization current.

Adenosine Diphosphate Ribose↗
PubMed1998

Lipid peroxidation, tissue necrosis, and metabolic and mechanical recovery of isolated reperfused rat heart as a function of increasing ischemia.

Isolated Langendorff-perfused rat hearts, after 30 min of preperfusion, were submitted to increasing times of global normothermic ischemia (1, 2, 5, 10, 20 and 30 min) or to the same times of ischemia followed by 30 min of reperfusion. Analysis of malondialdehyde, ascorbic acid, oxypurines, nucleosides, nicotinic coenzymes and high-energy phosphates was carried out by HPLC on neutralized perchloric acid extracts of freeze-clamped tissues. In addition, maximum rate of intraventricular pressure development and cardiac output of malondialdehyde, lactate dehydrogenase, oxypurines and nucleosides were monitored during both preperfusion and reperfusion. Besides decreasing energy metabolites and nicotinic coenzyme pool, prolonged ischemia produced oxidation of significant amounts of hypoxanthine and xanthine to uric acid and generation of detectable levels of malondialdehyde (0.002 micromol/g dry weight). After oxygen and substrate readmission, tissue and perfusate malondialdehyde increased only if previous ischemia was longer than 5 min, while lactate dehydrogenase was detected in perfusate of reperfused hearts following 10, 20, and 30 min of ischemia. Highest values of tissue malondialdehyde and total malondialdehyde output were recorded in reperfused hearts subjected to 30 min of ischemia (0.043 micromol/g dry weight and 0.069 micromol/30 min/g dry weight, respectively). Since tissue malondialdehyde was observed without detectable lactate dehydrogenase release in perfusate, it might be stated that malondialdehyde generation (i.e., lipid peroxidation) temporally preceded lactate dehydrogenase release (i.e., tissue necrosis). In reperfused hearts, evaluation of myocardial energy state and of mechanical recovery allowed us to determine times of ischemia beyond which reperfusion did not positively affect these metabolic and functional parameters. Main findings are that, under these experimental conditions, lipid peroxidation might be the cause and not the consequence of tissue necrosis and that duration of ischemia might be the factor deciding effectiveness of reperfusion.

Adenosine Triphosphate↗
PubMed1998

[Biliary lithiasis in childhood. A spectrum of diseases with different clinical significance during fetal life, childhood and adolescence].

On the basis of a research on fetal cholelithiasis, a review on the various form of cholelithiasis in pediatric age has been carried out. These include, in addition to fetal cholelithiasis, lithiasis in the first year of life and lithiasis in infancy and adolescence. These various expressions of the same pathology differ for incidence, predisposing factors, clinical situation, therapy and follow-up. The research conducted on fetal cholelithiasis showed an incidence of 0.39%, higher than expected. There isn't any maternal, obstetrical or fetal predisposing factor. The diagnosis is purely instrumental and is not correlated with known clinical or humoral data. The most frequent evolution is spontaneous resolution of the biliary echogenic images in absence of clinical manifestations; the complications are rare and not well documented. Cholelithiasis in the first years of life is correlated with malformative, pharmacologic or iatrogenic predisposing factors. The clinical situations include symptomless cases with spontaneous resolution and cases with serious complications. Therapy is to be chosen in each case in accordance with clinical features. Pediatric cholelithiasis beyond the first year of life, especially in the later childhood and adolescence, can be similar to cholelithiasis of adults for epidemiology, pathogenesis, symptomatology and therapy.

Adolescent↗
PubMed1998

[The sporadic use of intraoperative cholangiography during laparoscopic cholecystectomy].

The authors report their experience with 850 consecutive laparoscopic cholecystectomies performed from May 1990 to July 1997. In this series, despite a sporadic use of intraoperative cholangiography (IOC), there were no lesions of main biliary tract and there was only a biliary leaking cystic duct resolved with conservative treatment. The authors are satisfied with selective use of endoscopic cholangiography and sphincterotomy for the management of choledocholithiasis, and conclude that the use of IOC is not so essential to avoid iatrogenic lesions of main biliary tract, that could be avoid by applying a meticulous operative technique.

Cholangiography↗
PubMed1998

[The immediate reconstruction of the breast after a mastectomy for carcinoma. Our experience].

The authors surgically treated 281 consecutive women with breast cancer by breast conservation techniques (45.2%) or by mastectomy (38.8%), during a four-year period. Forty-five of these 281 patients (16%) were treated in the same period of time by mastectomy and immediate reconstruction (IR) of the breast. IR of the breast was performed by inserting a submuscular tissue expander at the same time of mastectomy (first stage of reconstruction). A second operation allowed the replacement of the expander with a prosthesis (second stage of reconstruction) and the simultaneous symmetrization of the contralateral breast (not always performed, however). In some cases nipple-areola complex was eventually reconstructed with a delayed surgical procedure (third stage of reconstruction). In the present paper the authors analyze the results and outline the advantages of IR. This easy and safe technique slightly increased the average operative time of a mastectomy, did not interfere with routine oncological follow-up, did definitely reduce patient's psychological trauma following mastectomy. The authors conclude that IR of the breast undoubtedly plays a major role in the so called "onco-plastic"" surgical management of breast cancer.

Adult↗
PubMed1998

Prevention of crescentic glomerulonephritis induced by anti-glomerular membrane antibody in tumor necrosis factor-deficient mice.

Tumor necrosis factor (TNF) is a proinflammatory cytokine playing a central role in the expression of endothelial adhesion molecules required for the recruitment of inflammatory cells. Proliferative glomerulonephritis induced by anti-glomerular basement membrane (GBM) antibody is characterized by the recruitment of inflammatory cells in the glomerulus followed by capillary damage and crescent formation. The glomerular pathology may be due to a large extent to TNF induction. We therefore tested this hypothesis in TNF-deficient mice. Anti-GBM antibody administration in sensitized wild-type mice resulted in deposition of immune complexes, followed by increased intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expression, as well as the influx of polymorphonuclear neutrophils (PMNs), lymphocytes, and macrophages. Distinct proteinuria preceded proliferative glomerulonephritis characterized by crescent formation. In the absence of TNF, the development of proteinuria was delayed and the formation of crescents was almost completely prevented. Although the deposition of immune complexes in glomeruli was comparable in both groups, the up-regulation of ICAM-1 and VCAM-1, as well as the influx of PMNs and lymphocytes, but not of monocytes, was dramatically reduced in TNF-deficient mice. Therefore, we conclude that TNF plays a key role in the recruitment of inflammatory cells and in the subsequent development of proliferative glomerulonephritis.

Animals↗
PubMed1998

[Juvenile polyposis coli associated with hereditary spherocytosis].

The first case of colorectal juvenile polyposis associated with hereditary spherocytosis is reported. Symptoms, diagnosis and therapy of juvenile polyposis are described along with the associated syndromes reported in the literature. The scientific and clinical consequences of this association are discussed.

Adenomatous Polyposis Coli↗
PubMed1997

[Pylorus-preserving pancreatoduodenectomy allows a better maintenance of glucose homeostasis].

BACKGROUND: Pancreatic diseases and pancreatic surgery usually cause a derangement of glucose metabolism ranging from a change in glucose tolerance test to insulin-dependent diabetes. The authors assess the changes in glycemia both in basal condition and after a challenge test in a group of patients who underwent Pylorus Preserving Pancreatoduodenectomy (PPPD) according to an original technique of reconstruction with two separate bowel loops. MATERIALS AND METHODS: Ten patients who underwent PPPD either for chronic pancreatitis or ampullar carcinoma were enrolled in this study. Pre- and postoperative assessment of pancreatic endocrine function was carried out in all the patients. The evaluation included: 1) oral glucose tolerance test (OGTT), 2) intravenous glucose tolerance test (IVGTT) and 3) glucagon challenge test. RESULTS: Plasma glucose level in basal condition, after oral glucose tolerance test, intravenous glucose tolerance test and glucagone challenge test, shows that insulin secretion and/or its effectiveness is not impaired after PPPD. Two patients with preoperative insulin-dependent diabetes needed a lower dose of insulin in the postoperative period. One patient responded abnormally to OGTT both in the preoperative and postoperative periods. Seven patients maintained normal glucose homeostasis in the postoperative period. DISCUSSION: PPPD allows a normal control of glucose metabolism. Better digestive and endocrine function noted in our patients in the postoperative period is due to the integrity of the stomach and the reconstruction technique with two bowel loops used to drain biliary and pancreatic secretion separately.

English Abstract↗
PubMed1997

[Fetal biliary lithiasis: ultrasonographic diagnosis and clinical interpretation. Report of 3 cases].

Fetal cholelithiasis was first diagnosed in 1983 and since then there have been only few reports about the presence of gallstones in the fetus. Maternal conditions, fetal or obstetrical predisposing risk factors have been proposed to have a causative role, but the pathogenesis of fetal gallstones remains unknown. Clinical sequelae of fetal gallstones are poorly understood as well as the role of fetal cholelithiasis in predisposing the adult to gallstones. We report on 3 patients whose cholelithiasis was diagnosed by obstetrical ultrasonography. Repeated ultrasound scans were performed in each patient until resolution of the US images. The goal of US was to correctly identify the number, size, and US features of the material within the gallbladder. The presence of distal shadowing or comet-tail artifact was assessed. Multiple, small echogenic foci without distal shadowing were recognized in the fetal gallbladder in our patients. Echogenic material was present at the US exams after birth in two patients and disappeared in the second month of life. In the third case echogenic foci disappeared during pregnancy. In all the cases, US showed no biliary tract abnormality, and neither the mothers nor the patients had clinical or laboratory findings consistent with liver or biliary diseases. The Authors discuss a diagnostic protocol to detect and follow-up gallstones in the perinatal period by ultrasonography. In our experience, fetal cholelithiasis confirmed to be a self-limiting disease without complications and did not require any form of therapy. However, a close follow-up is indicated in these patients until spontaneous resolution is demonstrated by US.

Cholelithiasis↗
PubMed1997

Modulation of proliferative activity and amino acid transport in chick embryo hepatocytes by EGF and retinoic acid.

In this work, the proliferative activity of chick embryo hepatocytes and its regulation by factors affecting cell growth, such as epidermal growth factor (EGF) and retinoic acid, were studied. The transport of nutritional molecules, like amino acids, was also investigated; in particular, the uptake mediated by the Na+ -dependent system A, known to be under hormonal and growth factor control. Moreover, some steps in the transduction pathway of mitogenic signal were analyzed, both for EGF and retinoic acid treatment. Results obtained suggest that chick embryo hepatocytes growth in an exclusive serum dependent way shows an early sensibility to EGF stimulation as regards to the proliferative activity and amino acid transport, responds to retinoic acid treatment and lack of contact inhibition. Moreover, as far as the signal transduction is concerned, at early stages, they do not seem to be able to utilize the same signal molecules as observed in adult life.

Amino Acids↗
PubMed1997

Juvenile polyposis coli and associated anomalies. Review of the literature and report of a case associated with hereditary spherocytosis.

A case of juvenile polyposis associated with hereditary spherocytosis is presented. All the anomalies associated with juvenile polyposis coli reported in the literature are reviewed. The clinical consequences of such a report are discussed along with the different forms of therapy for treating juvenile polyposis coli. To our knowledge, this is the first report in the literature of juvenile polyposis associated with hereditary spherocytosis.

Adenomatous Polyposis Coli↗
PubMed1996

Changes in the levels of glycerophosphoinositols during differentiation of hepatic and neuronal cells.

Glycerophosphoinositols are metabolites formed by a phosholipase A2 and a lysolipase specifically acting on membrane phosphoinositol lipids. High levels of these compounds characterize epithelial cells and fibroblasts transformed by ras and other cellular oncogenes. Here we have analyzed the glycerophosphoinositol levels in cells that are considered models of cell differentiation. Using rat hepatocytes at different stages of liver development we have shown that the glycerophosphoinositol basal levels of fetal cells were up to fourfold higher than in adult hepatocytes. No changes in glycerophosphoinositol were observed in regenerating rat liver, a model of differentiated cells proliferating in a synchronous manner, where only glycerophosphoinositol 4-phosphate increased by 80%. Similarly to fetal hepatocytes, a modest but significant increase (30%) in the levels of glycerophosphoinositols was observed in undifferentiated NG-108-15 cells as compared to the same cells induced to differentiate by cAMP. In a different neuronal cell line, PC12 cells, increased glycerophosphoinositol levels characterized the differentiated cells. Based on these observations we suggest that high glycerophosphoinositol levels characterize cellular phenomena associated with the activation of ras/mitogen-activated protein kinase pathways.

Animals↗
PubMed1996

Cloning and chromosomal localization of a cDNA encoding a mitochondrial porin from Drosophila melanogaster.

We have raised polyclonal antibodies against purified the Drosphila melanogaster mitochondrial porin. They showed high titre and specificity and were thus used as a tool for screening an expression library. The isolated clone 1T1 showed 74% sequence identity in the last 19 residues at the C-terminus of human porin. A subclone of 1T1, containing the porin-like sequence, was thus used as a probe for re-screening a cDNA library and several positive clones were plaque-purified. We present here the sequence of a 1363 bp cDNA encoding a protein of 279 amino acids. Its identity with porin was also confirmed by N-terminal Edman degradation of the purified protein. The D. melanogaster porin shows an overall 51.8% identity with human porin isoform 1 (porin 31HL or HVDAC1) and an overall 55.7% identity with human porin isoform 2 (HVDAC2). Hydrophobicity plots and secondary structure predictions showed a very high similarity with data obtained from known porin sequences. The D. melanogaster porin cDNA was used as a probe for in situ hybridization to polytenic salivar gland chromosomes. It hybridizes with different intensities in two sites, in chromosome 2L, at region 31E and in chromosome 3L at region 79D. Thus, also in Drosophila melanogaster porin polypeptide(s) belong(s) to a multigene family.

Amino Acid Sequence↗
PubMed1996

Activation of Sulfolobus solfataricus alcohol dehydrogenase by modification of cysteine residue 38 with iodoacetic acid.

Reaction of thermostable NAD(+)-dependent alcohol dehydrogenase from Sulfolobus solfataricus with iodoacetate at pH 9.0 and 37 degrees C significantly increases the oxidation rate of aliphatic and aromatic alcohols and decreases the reduction rate of aromatic aldehydes. The archaeal ADH is chemically modified and activated in a Michaelis-Menten-type reaction, where one molecule of the reagent binds per active site. NAD+ in micromolar concentration protects the enzyme against the inhibitor in an uncompetitive manner, while imidazole significantly increases the extent of the activation. Carboxymethylation selectively modifies one out of five cysteine residues per subunit, namely, Cys 38, located in the catalytic site, as determined by peptide and sequence analysis, and enhances by up to 25-fold the oxidation rate of benzyl alcohol. Carboxymethylated SsADH is less thermostable and shows a temperature optimum 30 degrees C lower than that of the native enzyme. The carboxymethylated enzyme exhibits a lower affinity toward the oxidized and reduced coenzyme. The dissociation constants for NAD+ and NADH determined at 25 degrees C and pH 8.8 are 60- and 200-fold higher, respectively, compared to the native enzyme. The significant isotope effect in alcohol oxidation suggests that hydride transfer partially limits the turnover rate of the reaction catalyzed by the modified enzyme, whereas the rate-limiting step for the native enzyme is NADH dissociation. Carboxymethylated enzyme probably gives higher maximum velocities of oxidation because of the faster dissociation of the modified enzyme-coenzyme complex.

Alcohol Dehydrogenase↗
PubMed1996

EGF responsiveness of hepatocytes after partial hepatectomy.

We investigate the effect of EGF on IP3 production, PLC gamma phosphorylation, calcium transients in rat hepatocytes isolated in quiescent liver (G0 phase of cell cycle) and at 4 h (G1 phase of cell cycle) and 24 h (M phase of cell cycle) after partial hepatectomy. Our results show that EGF does not utilize IP3 and calcium as its signal transduction molecules when the hepatocytes are in vivo stimulated to entry in the cell cycle. In particular the growth factor does not phosphorylate PLC gamma and induces a decrease in IP3 content. These data suggest that EGF utilizes different signal transduction to send information from receptor to nucleus during PH with respect to the quiescent liver.

Animals↗