Biomedical subjects

S Amarri

Publications and source records attributed to S Amarri.

27 records · Page 2Linked to original sources

PubMed1987

Isolation and characterization of a Mr = 110,000 glycoprotein localized to the hepatocyte bile canaliculus.

A Mr = 110,000 glycoprotein, GP 110, was partially purified using wheat germ agglutinin-Sepharose affinity chromatography from a bile canalicular-enriched membrane fraction denoted N2u of rat liver. This fraction was subjected to preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the Mr = 110,000 polypeptide was excised and used as an immunogen in rabbits. The antisera were found to specifically recognize a Mr = 110,000 polypeptide, named GP 110, in the N2u membrane fraction. In isolated hepatocytes, GP 110 was readily accessible to cell surface iodination catalyzed by lactoperoxidase at 4 degrees C and was judged by immunoprecipitation studies to contain about 2% of total radioactivity incorporated into externally oriented proteins of the cell. Immunoprecipitated GP 110 was shown by two-dimensional polyacrylamide gel electrophoresis to migrate with an approximate pI of 4.9. Indirect immunofluorescence on frozen liver sections demonstrated that GP 110 was primarily localized in the bile canaliculus. In corroborative studies employing subcellular fractionation, it was found that GP 110 was enriched nearly 19-fold in P2, a plasma membrane fraction primarily derived from the sinusoidal domain, and 44-fold in N2u. In contrast, only low levels of GP 110 were present in endoplasmic reticulum, mitochondrial, cytosolic, and nuclear-enriched fractions of liver. The physiological function of GP 110 is as yet unknown; antisera to it did not immunoprecipitate other known bile canalicular proteins of similar molecular weights. GP 110 was found to be extensively glycosylated relative to other known membrane proteins; approximately 33% of the apparent molecular weight appear to be carbohydrate. In agreement, limited removal of N-linked carbohydrate chains indicated that there are approximately eight chains/GP 110 polypeptide. Neuraminidase treatment of GP 110 resulted in a desialylated Mr = 85,000 polypeptide suggesting that the majority of carbohydrate chains on GP 110 are of the complex type.

Animals↗

PubMed1987

Isolation of domains of the plasma membrane of hepatocytes.

Several recent studies have demonstrated the ability of techniques based on immunoadsorption to selectively isolate specialized subregions of membranes, termed domains, which are derived from a larger more complex parent membrane like the plasma membrane. The immunoadsorbent is directed against a specific antigen that resides exclusively or predominantly in the membrane domain to be isolated. Thus, a monospecific antibody to the domain-specific antigen is required. In the present study we developed a method employing a modified immunoblotting strategy which could utilize polyspecific antibodies to isolate membrane vesicles derived from a specific membrane domain of the hepatocyte plasma membrane. We also used specific cell surface labeling of the hepatocyte plasma membrane by lactoperoxidase-catalyzed iodination at 4 degrees C and preparation of different sized vesicles by sonication to facilitate isolation of the specific domain. For this study, polyspecific antisera were raised in goats against a membrane fraction, denoted N2u, which is enriched in bile canalicular proteins. This antiserum recognizes, among other antigens, a 110,000 Mr polypeptide previously shown to be localized in the bile canaliculus (J. Cook et al. (1983) J. Cell. Biol. 97, 1823-1833). A monospecific antiserum was raised in rabbits against the rat hepatocyte asialoglycoprotein receptor, a sinusoidal domain-specific set of glycoproteins whose major form has a Mr of 43,000. These antisera were each coupled indirectly to different pieces of nitrocellulose by the immunoblotting protocol and were used to isolate membrane vesicles from a crude extract of liver plasma membrane prepared by sonication. The ratio of iodinated asialoglycoprotein receptor to the 110,000 Mr polypeptide in vesicles isolated by the affinity nitrocellulose immunoadsorbent method indicate a 10- to 15-fold enrichment of sinusoidal-derived vesicles relative to bile canalicular-derived membrane vesicles. These results show that the affinity nitrocellulose immunoadsorbent method can be used to isolate domain-specific vesicles. Further, the affinity immunoadsorbent method described here for the isolation of domains of the plasma membrane is an integrative one allowing isolation of vesicles present in relatively small concentration in crude cell extracts and it requires minimal ultracentrifugation time.

Affinity Labels↗

PubMedDate not supplied

The effect of dexamethasone and glucagon on the expression of hepatocyte plasma membrane proteins during development.

The regulation of different maturational processes in the liver is believed to be influenced by the hormonal system. The aim of this study was to investigate the effect of two hormones, glucagon and dexamethasone, on levels of plasma membrane proteins in rat liver cells during late fetal and early postnatal stages of development. For this purpose, 18-day-old rat fetuses and 1-day-old newborns were treated with glucagon or dexamethasone and killed at 22 days of gestation and 3, 5 and 7 days of age, respectively. Postnuclei liver membranes were isolated using a sucrose gradient method and assessed for levels of specific membrane proteins. Asialoglycoprotein receptor and 110,000 Mr glycoprotein, denoted GP 110, representing the sinusoidal and bile canalicular domains, respectively, were quantitated using the immunoblot method. Membrane enzymes alkaline phosphatase, leucine aminopeptidase and gamma-glutamyl transferase were evaluated using enzymatic methods. The data showed that glucagon and dexamethasone have a differential effect on membrane constituents according to the stage of development. Glucagon increased the levels of membrane enzymes during the late fetal stage but had no effect on liver membrane proteins in the newborn animal. In contrast, although dexamethasone elevated GP 110 in fetal rat livers, none of the other marker proteins was significantly affected. On the other hand, in newborns dexamethasone reduced the amount of asialoglycoprotein receptor and alkaline phosphatase and leucine aminopeptidase enzyme activities but greatly augmented the level of gamma-glutamyl transferase. Thus, glucagon primarily affects plasma membrane proteins in late gestation while dexamethasone does so during the early postnatal period. The roles that these two hormones may play during ontogeny is discussed with respect to liver development.

5'-Nucleotidase↗

PubMedDate not supplied

[Sedation in pediatric digestive endoscopy].

Sedation for children doing diagnostic or operative pediatric gastrointestinal endoscopy (PE) procedures is performed differently over the world and no consensus is yet agreed on the best paediatric endoscopy sedation (PES). Some centres do not use any sedation, especially in infants, most centre use some form of sedation: conscious sedation, deep sedation and general anaesthesia. We review sedation drugs and describe our centre protocol on 188 consecutive PE: oral premedication with flunitrazepam (0.05 mg/kg/dose) at least 30 min before procedure, petidine (1 mg/kg) followed by increasing boluses of midazolam (0.05 mg/kg up to a maximal 0.2 mg/kg or 5 mg) were given i.v. to obtain a conscious sedation. All PE could be performed and ended safely, PES resulted satisfactory in approximately 65% of patient having conscious sedation. SaO2 < 90% was observed in 2% of cases, one child had a respiratory depression after PE that resolved with flumanezil. Endoscopy and sedation was always performed by the PE team in the immediate vicinity of anaesthesiologists at work. PE can be safely performed with conscious sedation. Basic and advanced resuscitation skills are needed for the PE team who wish to perform both endoscopic and sedation procedures.

Child↗

PubMedDate not supplied

Antitransglutaminase enzyme-linked immune-adsorbed assay in coeliac disease diagnosis: evaluation of a diagnostic algorithm.

BACKGROUND: Tissue transglutaminase is the major autoantigen recognized in the sera of coeliac patients. An enzyme-linked immune-adsorbed assay based on tissue transglutaminase was recently used to measure serum tissue transglutaminase immunoglobulins A for coeliac disease diagnosis. OBJECTIVES: To determine the sensitivity, the specificity, the positive and negative predictive values of an immunoenzymatic assay based on guinea pig tissue transglutaminase, to compare antititransglutaminase immunoenzymatic assay to the antiendomysium immunofluorescent assay, and to define a cost-effective sequence to execute serum antibody determination in coeliac patients. METHODS: We assessed for coeliac disease antibodies 91 pediatric patients with symptoms suggestive of coeliac disease, and 23 patients with coeliac disease on a gluten-free diet as controls. RESULTS: Antitransglutaminase immunoglobulins A showed 93.1% sensitivity, 93.6% specificity, 87.1% positive and 96.7% negative predictive values. Antitransglutaminase immunoglobulins A were significantly higher in antiendomysium positive subjects. Correlation between antitransglutaminase immunoglobulins A and antigliadin immunoglobulins A was not significant. DISCUSSION: Our results show that antitransglutaminase immunoenzymatic assay represents a cost-effective strategy for patients' serological evaluation and it could substitute EMA determination, which could be considered a second level evaluation.

Adolescent↗

PubMedDate not supplied

[High-dose oral bacteria-therapy for chronic non-specific diarrhea of infancy].

The Authors evaluate the effectiveness of oral bacteriotherapy using a combination of anaerobe fecal Lactobacilli for chronic non specific diarrhea of infancy. A double blind study was carried out in a total of 40 children treated with low and high doses of bacteria. The results confirm the importance of fecal flora in this disease and support the hypothesis that oral bacteriotherapy can improve clinical and laboratory presentation especially when given at high doses.

Administration, Oral↗

PubMedDate not supplied

[Atrophy of the duodeno-jejunal mucosa in cow's milk protein intolerance. Importance of cell-mediated immunologic factors].

Cow's milk sensitive enteropathy has been described several times but in spite of that, it is still a problem concerning the pathogenesis. Our study involves the children hospitalized from 1974 to 1984 in the First Department of Pediatrics, University of Modena. Patients were suffering from chronic diarrhea and malabsorption. At the first biopsy each child showed atrophy of the small intestinal mucosa. All patients had been fed fed with gluten. We have followed the protocol for Celiac Disease's diagnosis; we found proved 85% of cases, excluded 15%. These last cases may be considered as cow's milk sensitive enteropathy. We catamnestically considered all the clinical and laboratory data of the two groups in the purpose of selecting significative parameters for a differential diagnosis. The data meaning fully different between the two groups resulted: family history of allergy, recurrent infections, positive occult blood in the stools, eosinophils in blood greater than 400/mm3 serum IgE value greater than 97 degrees P X (p less than 0.01). On the ground of recent studies the involvement of the cell-mediated immunity in cow's milk sensitive enteropathy is supposed.

Animals↗

PubMedDate not supplied

[Clinical study on the efficacy of a sustained-release theophylline-based preparation in infants with chronic asthma].

Authors describe 9 infants aged between 3 and 17 months, affected by recurrent episodes of bronchial asthma (at least one crises even month for three following months) and treated with sustained-release theophylline. During the 6 months of follow-up a total of 8 episodes of bronchial asthma in 7 subjects were observed. Seven out of 8 of these episodes occurred during the period of suspension of the therapy with the sustained-release theophylline. In each subjects, after 6 hours from the drug administration on average of 4-8 determinations of the theophylline blood levels were performed. More than 70 percent of the theophylline blood values has been found within the normal therapeutic range (6-20 micrograms/ml).

Asthma↗

PubMedDate not supplied

[Atherosclerosis: a childhood problem].

The project "Precursors of Atherosclerosis (ATS) in Children" following the protocol of WHO started in Modena in 1981/82. A total of 527 schoolchildren of 6, 9, 12 and 15, living in the area around Modena, Emilia Romagna Region, were examined, sampled from whole schools or classes. Each group exceeds the minimum of 100 children with the exception of the group including subjects of 15. The population sampled is fairly homogeneous. There are no immigrants to the area and the intra-population differences due to social-classes are minimal. The standard of life is very high: the rate of income is one of the highest in Italy and the incidence of ATS manifestations is very high. The children will be reexamined each year for three years at the same season and the study will be over in 1984. A questionnaire with family story has been filled by the parents and the parents were directly examined about: height, blood pressure, cholesterolemia, triglyceridemia, smoking habit. Following the protocol in each child are determined: height, weight, Quetelet's index (kg/m2), skinfold thickness, blood pressure, cholesterolemia, triglyceridemia, sexual maturity and smoking habit. The statistical elaboration methods of data are chosen in cooperation with the "Centro di Calcolo" of the University of Modena, and elaborated with the Statistical Package for the Social Science (SPSS) method.

Adolescent↗