Biomedical subjects

A Comino

Publications and source records attributed to A Comino.

At least 19 recordsLinked to original sources

PubMed2001

Seven novel point mutations in the uroporphyrinogen decarboxylase (UROD) gene in patients with familial porphyria cutanea tarda (f-PCT).

In this work, we describe seven novel molecular defects in the uroporphyrinogen decarboxylase gene responsible for familial porphyria cutanea tarda in Italian subjects with reduced erythrocyte URO-D activity. Four of these molecular abnormalities (R142Q, L161Q, S219F, P235S) are missense mutations, one (Q206X) is a nonsense mutation, one (IVS8-1 G>C) is a splicing defect causing the exon 9 deletion and one (1107 G>A) is located in the 3' untranslated region of UROD gene. All the amino acid substitutions fall in conserved regions in several organisms suggesting an important role in catalysis or in the protein structure stabilization. Three of these mutations have been detected in more than one subject. These results suggest a molecular heterogeneity at the UROD locus in Italian PCT patients although recurrent mutations have been identified.

3' Untranslated Regions↗

PubMed2001

Membrane-bound iron contributes to oxidative damage of beta-thalassaemia intermedia erythrocytes.

Iron-dependent oxidative reactions in beta-thalassaemic erythrocyte membranes are involved in premature cell removal and anaemia. We studied 22 beta-thalassaemia intermedia patients (i) to assess if membrane iron accumulation influences the oxidative damage to thalassaemic cells, and (ii) to see whether the mechanisms of haemoglobin destabilization described in vitro have indicators in circulating erythrocytes. Serum non-transferrin-bound iron as potentially toxic iron for erythrocytes was also evaluated. Membrane-bound free iron significantly correlated to bound haemichromes, suggesting a causal relation, but was poorly related to serum non-transferrin iron, which seems to contribute little to damage from outside the cells. The spleen played an important role in the removal of cells with more membrane iron.

Adult↗

PubMed2000

The role of the bacitracin ABC transporter in bacitracin resistance and collateral detergent sensitivity.

The bacitracin resistance of Bacillus licheniformis, a producer of bacitracin, is mediated by the ABC transporter Bcr. Bacillus subtilis cells carrying bcr genes on high-copy number plasmids developed collateral detergent sensitivity, as did human cells with overexpressed multidrug resistance P-glycoprotein. Resistance against bacitracin and sensitivity of resistant cells to detergents were shown to be inseparable phenomena associated with the membrane part of Bcr transporter, namely protein BcrC. A fused protein, consisting of ATP-binding protein BcrA and membrane component BcrC was constructed. It resembled a half molecule of P-glycoprotein and was capable of providing a significant degree of antibiotic resistance and detergent sensitivity.

ATP-Binding Cassette Transporters↗

PubMed2000

Oral isobutyramide therapy in patients with thalassemia intermedia: results of a phase II open study.

A pilot phase II open study on 12 patients with thalassemia intermedia (7 men, 5 women; age 31 +/- 2.0 years SE) treated with oral isobutyramide, a derivative of butyric acid (150 mg/kg body wt/day), was performed in order to evaluate the effect of this compound in stimulating hemoglobin F (HbF) production. No patient underwent blood transfusion in the 1-year time frame prior to the study. Nine patients were splenectomized. Safety was monitored by clinical and laboratory tests. Efficacy was assessed in terms of the non-alpha/alpha globin chain biosynthetic ratio and the percentage increase of HbF. The study design consisted of a screening phase, a treatment phase of 28 days, and a posttreatment follow-up of 28 days. All patients completed the study. Compliance to treatment was 100%. No drug-related adverse event was recorded. We observed little or no increase in the non-alpha/alpha ratio in the majority of patients. Six patients showed a percentage increase of HbF at the end of treatment and in 5 of those 6 further increases at the end of the follow-up period were observed. The change in percentage of HbF over time was close to significance both in the treatment period (P = 0. 06) and in the follow-up period (P = 0.08). These results indicate that butyrate derivatives can stimulate fetal hemoglobin in patients with intermediate thalassemia. Testing of the effects of different schedules of administration of isobutyramide will be required in order to determine the optimal use of this compound in the treatment of the beta-thalassemia syndromes.

Administration, Oral↗

PubMed2000

Interaction trap experiment with CDC6.

CDC6 is an essential gene of yeast Saccharomyces cerevisiae. Although DNA sequence of the gene is available for a long time, biochemical function of Cdc6 protein in the cell cycle remains unclear. Using the interaction trap experiment we were looking for proteins interacting specifically with Cdc6. Four gene products interacting with Cdc6 were detected. By sequence analysis we found that ECM11 codes for the protein involved in the cell wall synthesis, YNL201 codes for the protein of unknown function, probably involved in the carbon metabolism, YOR279 codes for protein of completely unknown function with no significant similarity with any known protein, and the interaction with Ty1 retrotransposition element was also found. The strongest interaction with Cdc6 bait measured as beta-galactosidase activity was observed with ECM11 and YNL201; YOR279 interacts slightly weaker. The weakest beta-galactosidase activity was obtained by Ty1A element. The strongest suppression of cdc6-1 mutation was observed by Ty1A element, the slight one with ECM11 and YNL201 but no suppression of thermosensitive mutation was detected for YOR279.

Cell Cycle Proteins↗

PubMed1998

Butyrate trials.

The aims of this study were to ascertain tolerability, safety and efficacy of oral isobutyramide (150 mg/kg bw/day) in stimulating fetal hemoglobin production in twelve thalassemia intermedia patients. Patients were treated for 28 days and followed for a further 28 days. Efficacy was monitored by non-alpha/alpha globin chain ratio and percentage of HbF. Five patients experienced increases of non-alpha/alpha ratio ranging between 5.3 and 100% at the end of treatment. Five patients show an increase of HbF ranging between 4.4 and 26%. Their HbF% continues to increase during follow-up period. The analysis of variance for HbF showed a time effect close to significance both in treatment period (p = 0.06) and in follow-up period (p = 0.08). Moreover, to evaluate a possible erythropoietic modification, serum Erythropoietin (sEpo) and serum Transferrin Receptor (sTfR) were evaluated. Serum Epo and sTfR levels were significantly increased during treatment (p < 0.05 vs baseline).

Adult↗

PubMed1997

Amplification of bacitracin transporter genes in the bacitracin producing Bacillus licheniformis.

We have amplified the previously cloned and sequenced genes of the bacitracin exporter (bcr), a member of the ATP-binding transport protein family, within the chromosome of the bacitracin producing Bacillus licheniformis. Amplification of the transporter genes was followed by greatly increased bacitracin resistance. Antibiotic production was enhanced at a low level of bcr genes amplification. An enlarged increase in the copy number of the bcr genes negatively affects the overall growth of bacteria.

ATP-Binding Cassette Transporters↗

PubMed1997

The expression of uridine diphosphate glucuronosyltransferase gene is a major determinant of bilirubin level in heterozygous beta-thalassaemia and in glucose-6-phosphate dehydrogenase deficiency.

We evaluated the effect of Gilbert's syndrome, the most common defect of bilirubin conjugation, on the bilirubin levels of subjects with inherited haematological disorders which cause increased bilirubin production. 57 patients heterozygous for beta-thalassaemia, 21 with G6PD deficiency and 44 controls were examined by typing the TATA-box in the promoter of the gene uridine diphosphate glucuronosyltransferase 1A. Nearly 80% of patients with increased bilirubin levels were heterozygous or homozygous for the UGT1A TA(7) variant associated with Gilbert's syndrome. These findings indicate that Gilbert's syndrome accounts for a large proportion of the variability of bilirubin levels in beta-thalassaemia and G6PD deficiency.

Gene Expression↗

PubMed1997

Prevalence of myocarditis at autopsy in Turin, Italy.

OBJECTIVE: To evaluate the prevalence of myocarditis in a general hospital in Turin, Italy. DESIGN: We retrospectively reviewed 17162 postmortem records from autopsies routinely performed at San Giovanni Battista General Hospital, Turin, between 1965 and 1994. RESULTS: Applying the so-called Dallas criteria, myocarditis was histologically found in 91 cases (0.53%, 95% CI 0.4 to 0.7). The prevalence increased, reaching a peak between 1985 and 1994 (1.2%, 95% CI 0.9 to 1.6). The disease was found more frequently in patients from 20 to 39 years of age, with no difference between males and females. The present data were compared to those of a previous study, performed in 1985 and 1993 to 1994, in which we had prospectively taken into account 605 autopsies (not comprised in the present retrospective study) with standardized myocardial sampling for histological examination: a 5.1% prevalence was found (nearly five times as high as that retrospectively detected in the same period). CONCLUSIONS: If a standardized method of myocardial samples for microscopic examination is not followed, it is possible that myocarditis is overlooked in an unsuspected number of cases.

Adolescent↗

PubMed1996

Flow cytometric DNA analysis of cirrhotic liver cells in patients with hepatocellular carcinoma can provide a new prognostic factor.

BACKGROUND: DNA flow cytometry of hepatocellular carcinoma (HCC) cells has been investigated in many studies, but, to the best of our knowledge, there are no data on DNA analysis of cirrhotic parenchyma around the HCC. In this study, cell kinetics and ploidy of parenchymal cells around HCC were performed to ascertain if this would predict the possibility of recurrence in the cirrhotic areas. METHODS: The DNA content of 93 cases of HCC and of cirrhotic liver around the tumor nodules was analyzed by flow cytometry. Ploidy and proliferative index of HCC and cirrhotic liver were compared with macroscopic, histologic, and clinical features of each case and linked with the behavior of these tumors. Survival curves were assessed according to the Kaplan-Meier method. A multivariate analysis based on Cox proportional hazards regression model was performed on cases of diploid cirrhosis cells in which the S-phase fraction was evaluable. RESULTS: The univariate analysis of survival suggested significant roles for age, number of intrahepatic nodules, Edmondson-Steiner's classification, portal invasion, vascular invasion, presence of necrosis, hepatitis B surface antigen, alpha-feto-protein, Child's score, ploidy, and S-phase fraction of HCC cells. The DNA analysis of the cirrhotic cells showed that polyploidy was dramatically reduced in patients with HCC, compared with normal hepatocytes, and aneuploid clones were present among diploid cells. High S-phase fraction of cirrhotic cells and Child-Pugh classification were the strongest independent parameters affecting the tumor behavior in this study. CONCLUSIONS: The results of this study suggest that S-phase fraction of cirrhotic liver parenchyma may be employed as a new parameter in the prognostic evaluation of HCC patients.

Adult↗

PubMed1995

Bacillus licheniformis bacitracin-resistance ABC transporter: relationship to mammalian multidrug resistance.

The nucleotide sequence of the Bacillus licheniformis bacitracin-resistance locus was determined. The presence of three open reading frames, bcrA, bcrB and bcrC, was revealed. The BcrA protein shares a high degree of homology with the hydrophilic ATP-binding components of the ABC family of transport proteins. The bcrB and bcrC genes were found to encode hydrophobic proteins, which may function as membrane components of the permease. Apart from Bacillus subtilis, these genes also confer resistance upon the Gram-negative Escherichia coli. The presumed function of the Bcr transporter is to remove the bacitracin molecule from its membrane target. In addition to the homology of the nucleotide-binding sites, BcrA protein and mammalian multidrug transporter or P-glycoprotein share collateral detergent sensitivity of resistant cells and possibly the mode of Bcr transport activity within the membrane. The advantage of the resistance phenotype of the Bcr transporter was used to construct deletions within the nucleotide-binding protein to determine the importance of various regions in transport.

ATP-Binding Cassette Transporters↗

PubMed1995

DNA flow cytometric analysis of abortions. A simple method for detection of triploidy and tetraploidy in the trophoblastic cells.

By flow cytometric analysis of nuclear DNA content it is possible to demonstrate the cellular clones that have a quantity of DNA higher or lower in comparison with that of diploid nuclei. The possibility of measuring DNA ploidy by flow cytometry provides a simple way to asses triploidy and tetraploidy in placental tissue. In this investigation, are reported the results of the DNA analysis in a series of 540 consecutive spontaneous abortions or suction curettage material obtained after intrauterine death, which was detected by ultrasound examination. At microscopy 351 (65.0%) cases showed feature of normal placentas, 147 (27.2%) of hydropic abortus, 27 (5.0%) of partial hydatidiform mole and 15 (2.8%) of complete hydatidiform mole. DNA flow cytometric analysis showed triploidy in 38 cases (7.0%) and tetraploidy in 12 cases (2.2%). Comparing microscopic feature and ploidy, 12 normal placental specimens were triploid, 6 were tetraploid. Nine hydropic abortuses had a triploid DNA content, 5 a tetraploid DNA content. In the group of partial hydatidiform moles triploidy has been found in 14 cases, whereas tetraploidy in one case and diploidy in 12 cases. Twelve complete hydatidiform moles showed a diploid DNA content and 3 a triploid one. The incidence of poliploid pregnancies has been higher among young patients. In most cases the poliploid pregnancy was the first pregnancy of the patient. DNA flow cytometric analysis is a simple and useful mean to state etiology of many spontaneous abortion, even when histology is negative. This analysis must be associated with morphology in this field.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Spontaneous↗

PubMed1995

[Adult myocarditis in a general hospital: observations on 605 autopsies].

We studied 605 necropsies carried out in a general hospital (San Giovanni battista in Turin), during the years 1985-86 (405 cases) and 1993-94 (200 cases). A standardized sample of myocardium was systematically taken and submitted to histological examination. Thirty-one cases of myocarditis were found (5.1%). Th disease was more frequently observed in the age group from 30 to 49 years and in people dying of malignancies: females showed higher frequency than males (7.4% vs. 4%), with differences nearly significant from a statistical point of view. None of these cases was recognized by the physicians. The prevalence rate of myocarditis in the present series is higher than in retrospective reviews, where microscopic examination of myocardium was not systematically performed. The discrepancies between clinical results and pathological findings confirm that myocarditis is often unsuspected by the physicians.

Adolescent↗

PubMed1994

Cell proliferation indices, morphometry and DNA flow cytometry provide objective criteria for distinguishing low and high grade bladder carcinomas.

Argyrophilic nucleolar organizer region (Ag-NOR) analysis, proliferating cell nuclear antigen (PC-NA/PC10) and MIB-1 immunohistochemistry, nuclear morphometry and DNA flow cytometry have been performed on formalin-fixed, paraffin-embedded biopsies from 50 patients with transitional cell carcinoma of the urinary bladder. The mean AgNOR count was 6.01 for the 17 grade 1 (G1), 7.59 for the 21 G2 and 13.33 for the 12 G3 carcinomas (p < 0.001). The mean PCNA score was 15.03% for G1, 24.04% for G2 and 40.01% for G3 cases (p < 0.001). The mean MIB-1 score was 11.31% for G1, 17.09% for G2 and 34.47% for G3 carcinomas (p < 0.001). The mean nuclear area was 35.53 microns2 for G1, 38.65 microns2 for G2 and 83.62 microns2 for G3 cases (p < 0.001). Aneuploidy rates were significantly higher (91.7%) in G3 than in G2 (42.9%, p < 0.01) or G1 cases (47.1%, p < 0.05) but not different for G1 versus G2 cases (p = 0.94). While many overlaps of values were seen between G1 and G2 tumours, no overlaps were found between G3 and G1/G2 tumours. Significant differences of values were also found between pTa and invasive tumours (p < 0.0001 for AgNOR count and PCNA score; p < 0.001 for MIB-1 score and mean nuclear area; p < 0.01 for DNA ploidy); however many overlaps were seen. Our findings indicate that the quantitative parameters obtained with different methods are associated with histological grade of bladder urotheliomas and may improve the grading reproducibility. In addition, the absence of overlaps between G3 and G2/G1 carcinomas supports the tendency to classify bladder urotheliomas in only two categories of malignancy.

Aneuploidy↗

PubMed1994

Antagonists of bacitracin.

Three groups of substances were identified which inhibit the bactericidal activity of bacitracin. Beside two divalent metals, Mg2+ and Ca2+, and a metabolite with chelating properties, citrate, the most pronounced effect was observed with pyrophosphate. Metals probably prevent access of bacitracin to the lipid carrier whereas metabolites with chelating properties deprive the bacitracin of a metal ion needed for its binding to the lipid carrier. Pyrophosphate, effective as an antagonist at very low concentrations, may intercept the binding of bacitracin to the pyrophosphate part of the target molecule.

Bacillus subtilis↗

PubMed1993

Role of platelet-activating factor in polymorphonuclear neutrophil recruitment in reperfused ischemic rabbit heart.

This study investigated the role of platelet-activating factor in the recruitment of polymorphonuclear neutrophils (PMN) in a rabbit model of cardiac ischemia and reperfusion. The accumulation of PMN was evaluated 2 and 24 hours after removal of 40 minutes of coronary occlusion by morphometric analysis and 111In-labeled PMN infiltration. The administration of two structurally unrelated platelet-activating factor-receptor antagonists (SDZ 63-675, 5 mg/kg body weight, and WEB 2170, 5 mg/kg body weight) before reperfusion significantly reduced the accumulation of PMN, as well as the hemodynamic alterations and the size of necrotic area. Two hours after reperfusion, the percentage of increase of 111In-labeled PMN in transmural central ischemic zone was significantly reduced in rabbits pretreated with SDZ 63-675 (51.4 +/- 7.9) or WEB 2170 (32.4 +/- 8.8) with respect to untreated rabbits (107.6 +/- 13.5). The morphometric analysis of myocardial sections confirmed the reduction of PMN infiltration at 2 hours and demonstrated that at 24 hours the phenomenon was even more significant. In addition, SDZ 63-675 and WEB 2170 prevented early transient bradycardia and hypotension and reduced the infarct size, judged by staining with tetrazolium at 2 and 24 hours after reperfusion, and by histological examination at 24 hours. These results suggest that platelet-activating factor is involved in the accumulation of PMN in the reperfused ischemic myocardium and contributes to the evolution of myocardial injury.

Animals↗

PubMed1992

Imaging lung cancer by scintigraphy with Indium 111-labeled F(ab')2 fragments of the anticarcinoembryonic antigen monoclonal antibody FO23C5.

BACKGROUND: Anticarcinoembryonic (CEA) monoclonal antibodies are able to react specifically with the antigen and have the potential for the detection of CEA-bearing tumors. METHODS: The authors photoscanned with indium 111 (111In)-labeled F(ab')2 fragments of the murine CEA monoclonal antibody FO23C5 63 patients with a newly diagnosed and pathologically documented bronchogenic carcinoma. Planar dual views of the thorax, abdomen, and brain were acquired between the 24th and 144th hour after the radiotracer injection. Patients had a complete pretreatment workup, which included a routine multiorgan computed tomography (CT) scan, and the determination of the serum and tissue CEA concentration. All patients were followed up clinically and radiologically. Nineteen needle aspirations and biopsies, 23 surgical explorations, and 4 mediastinoscopic studies yielded 121 pathologically documented sites of reference. RESULTS: Fifty-seven of 63 scans were positive for the primary tumor (sensitivity, 0.90). The uptake of the radiotracer correlated significantly with the intensity of tissue CEA expression (Spearman R [Rs], 0.25; P less than 0.05), but not with the serum CEA level or with the histotype. Overall, the sensitivity of the anti-CEA immunoscintigraphy (IS) for the N1, N2, N3, T3, T4, and M1 disease (1987 International Union Against Cancer [UICC] staging classification) was 0.67, 0.64, 0.62, 0.31, 0.29, and 0.86, respectively. Corresponding values of specificity were 0.67, 0.81, 0.90, 1, 1, and 0.93; accuracy values were 0.67, 0.71, 0.85, 0.71, 0.76, and 0.92. The authors limited the analysis to all of the pathologically documented sites and obtained slightly superior values but no meaningful differences. The stage derived from IS readings was correct in 33 patients. The same figure was obtained after an initial clinical workup, which included physical examination, laboratory routine tests, chest radiographs, bronchoscopy, and any diagnostic procedure indicated by those tests. CONCLUSIONS: Anti-CEA FO23C5-F(ab')2 fragments are not yet "magic bullets" for perfect diagnoses; however, their staging potential seems to be remarkable. Technical improvements, single-photo emission CT, and the use of such fragments in combination with other imaging techniques might enable researchers to further improve the current results.

Adult↗

PubMed1992

Flow cytometric studies in spontaneous abortions. Applications in the medico-legal practice.

In the medico-legal practice differential diagnosis between spontaneous and non-spontaneous abortion is important because causes of pregnancy wastage are often obscure and, moreover, spontaneous abortion is more common than accidental or voluntary. In all the cases in which the cause of abortion is not otherwise detectable and especially in cases of discovery of fetal adnexa, it is necessary to investigate genetic causes. Recently, DNA flow cytometric analysis has been applied in determining the genetic causes of spontaneous abortions. Among karyotypic abnormalities, flow cytometric analysis on paraffin embedded material can detect only polyploidies (triploidy and tetraploidy). Trisomies, monosomies and structural anomalies cannot be detected. In our study we tried to establish whether flow cytometry could be useful in determining the genetic cause of spontaneous abortions, in the lack of any other detectable cause. Histologic examination and flow cytometric analysis were performed on a series of 395 consecutive spontaneous abortions. Histologic examination allowed the detection of a molar pattern in about 9% of cases. DNA flow cytometric analysis showed diploidy in 346 (87.59%) cases, triploidy in 37 (9.36%) cases and tetraploidy in 12 (3.03%) cases. Combined microscopic and flow cytometric analysis revealed abnormalities in 17.5% of cases. A non-diploid pattern is more frequent in molar cases (P less than 0.001). Flow cytometry seems to be interesting in forensic pathology, as it allows the detection of some frequent genetic abnormalities in dead tissues and cells, when other techniques are no longer practicable.

Abortion, Illegal↗