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Biomedical subjects

M Vecchi

Publications and source records attributed to M Vecchi.

At least 73 records · Page 4Linked to original sources
PubMed1995

Decrease of intraocular pressure after subconjunctival injection of mitomycin in human glaucoma.

OBJECTIVE: To investigate the effects of a subconjunctival injection of mitomycin on the intraocular pressure in human eyes affected by glaucoma. DESIGN: Consecutive case series, prospective study, intraocular pairwise comparison (paired samples Student's t test adopted). SETTING: Hospital-based glaucoma clinic. PATIENTS: Twelve consecutive patients with bilateral glaucoma and monolateral blindness, intraocular pressure greater than 30 mm Hg in the blind eye (mean of the two highest values of the diurnal curve, confirmed at 96-hour interval), and no previous bulbar surgery. INTERVENTION: Subconjunctival injection of 0.5 mL of 0.2% mitomycin in the upper temporal quadrant, preceded and followed by treatment with topical indomethacin. MAIN OUTCOME MEASURE: Analysis of the variance of the mean intraocular pressure before and after the injection of mitomycin in each eligible eye. RESULTS: An intraocular pressure decrease was observed in each eligible eye the day after the treatment (mean [+/- SD] decrease, 7.15 +/- 1.46 mm Hg). The effect was still detectable at the end of the 60 days of follow-up (mean [+/- SD] decrease, 5.67 +/- 1.61 mm Hg). No change of intraocular pressure, in the meantime, was observed in the fellow eye. CONCLUSIONS: Topically applied mitomycin induces a decrease of intraocular pressure in human glaucomatous eyes. Our data confirm previous results obtained in albino rabbits and support the hypothesis that mitomycin exerts a still unknown direct effect on aqueous humor dynamics in the eye.

Adult↗
PubMed1995

Primary biliary cirrhosis is associated with specific changes in liver IgG-bearing cell subpopulations.

BACKGROUND/AIMS: The density of total IgG-bearing cells and the distribution of their subclasses were studied in the liver of patients with primary biliary cirrhosis. METHODS: Immunohistochemistry and computerized image analysis were used to compare liver specimens from 18 patients with primary biliary cirrhosis and 28 with chronic hepatitis of different etiology. RESULTS: The density of total IgG-bearing cells was similar in the two groups. However, in patients with primary biliary cirrhosis the proportion of IgG3-positive cells was significantly higher than in patients with chronic hepatitis (53 +/- 7% vs. 7.5 +/- 2.4%) (p < 10(-8)). Conversely, IgG1-positive cells were significantly less prevalent in patients with primary biliary cirrhosis than in chronic hepatitis patients (27 +/- 6.9% vs. 68 +/- 7.2%, p < 10(-8)). Stratification of patients with primary biliary cirrhosis according to histology did not show any difference in the distribution of IgG subclasses associated with the progression of disease. CONCLUSION: These data suggest a pathogenetic role of local IgG3-bearing cells in primary biliary cirrhosis.

Autoantibodies↗
PubMed1994

Arginine-23 is involved in the catalytic site of muscle acylphosphatase.

Three mutants of human muscle acylphosphatase in which arginine-23 was replaced by glutamine, histidine and lysine, respectively, were prepared by oligonucleotide-directed mutagenesis of a synthetic gene coding for the enzyme. All mutants, purified by affinity chromatography, were almost completely unable to catalyze the hydrolysis of the substrate. 1H-NMR spectroscopy experiments showed the absence of any major conformational changes of the three mutants with respect to the wild-type recombinant enzyme. Equilibrium dialysis experiments demonstrated that the mutated proteins lost the ability of binding inorganic phosphate, a competitive inhibitor of the enzyme. These results strongly support an involvement of arginine-23 at the phosphate binding-site of acylphosphatase, confirming the hypothesis of the existence of a phosphate binding structural motif recently proposed by other authors.

Acid Anhydride Hydrolases↗
PubMed1994

Persistence of "wild-type" and "e-minus" hepatitis B virus infection in chronic healthy HBsAg/anti-HBe positive carriers.

We examined nine chronic healthy hepatitis B surface antigen/antibody to hepatitis Be carriers with consistently normal liver chemistries and negative serum hepatitis B virus-DNA. Liver biopsy, performed twice, 10-11 years apart in all patients, showed normal histology and negative hepatitis B core antigen. DNA extracted from the second liver biopsy specimen, from 1 ml of serum from each patient and from an additional serum sample of 6 ml from two patients, was tested for pre-C/C and pre-S regions of hepatitis B virus-DNA by polymerase chain reaction amplification. Viral sequences were found in six of nine liver DNA extracts. In four cases both pre-C/C and pre-S regions were amplified, while the pre-C/C alone and the pre-S alone were detected in one case each. Direct sequencing of the amplified DNAs revealed no significant genomic changes in the pre-S and Core regions, while analysis of the pre-Core demonstrated the presence of a double viral population (wild-type and "e-defective") in four cases, and only "e-defective" hepatitis B virus in one case. No hepatitis B virus genomes were revealed in the serum sample when DNA was extracted from 1 ml of serum, while viral sequences were detected in both extracts of 6 ml of serum, indicating the presence of very low levels of viremia. These data suggest that episomal hepatitis B virus-DNA may persist for years in the liver of chronic healthy carriers in a latent state which may involve both wild-type and HBeAg-defective hepatitis B virus.

Carrier State↗
PubMed1994

Antibodies to neutrophil cytoplasm in Italian patients with ulcerative colitis: sensitivity, specificity and recognition of putative antigens.

We studied the prevalence of perinuclear antineutrophil cytoplasmic antibody (p-ANCA), as detected by immunofluorescence, in 290 Italian subjects. One hundred and two were affected by ulcerative colitis, 48 by Crohn's disease, 40 by gluten-sensitive enteropathy and 100 were normal subjects. The prevalence of p-ANCA was significantly higher in ulcerative colitis patients (45.1%) as compared to Crohn's disease patients (4.8%), gluten-sensitive enteropathy (0%) and normal subjects (1%; p < 0.0001 ulcerative colitis vs. all other groups). In this setting, the overall specificity of the test was 98.1% with a sensitivity of 45.1%. The specificity slightly decreased to 95.1% when ulcerative colitis patients were compared to patients with Crohn's colitis. In our series, p-ANCA appeared to be more prevalent in ulcerative colitis patients with more aggressive disease. ELISA experiments performed in order to identify the putative antigen(s) recognized by p-ANCA-positive sera showed that 8 of 12 sera positive at immunofluorescence reacted with at least one of the neutrophil preparations tested. The reactivities were directed towards various neutrophil preparations. Preabsorption with the specific antigen recognized by ELISA significantly inhibited the p-ANCA immunofluorescence reactivity indicating that p-ANCA reactivity might derive from the recognition of heterogeneous neutrophil-associated antigens.

Adolescent↗
PubMed1994

Expression of human acylphosphatase in Escherichia coli affects intracellular calcium levels.

In vitro experiments demonstrated the ability of acylphosphatase to hydrolyze the phosphorylated intermediate that is formed during the activity of Na+, K(+)- and Ca(2+)-ATPases of mammalian cells membranes. In order to investigate the effect of this enzyme on intracellular cation levels, a synthetic gene for human muscle acylphosphatase has been expressed in E. coli strains BL21 and JM101. Intracellular total steady-state calcium concentration, as measured by isotopic exchange, was significantly higher in transformed cells as compared to controls and the rising was dependent on the level of acylphosphatase expression. Accordingly also free intracellular calcium concentration, as measured by Fura-2 fluorescence, increased in transformed cells. On the other hand, phosphate levels were not affected by the expression of acylphosphatase, while sodium and rubidium levels increase in transformed cells. Intracellular pH resulted to be slightly affected by the expression of acylphosphatase, cytoplasm of transformed JM101 bacteria being more alkaline (pH 7.45) as compared to control cells (pH 7.40). On the basis of these results, it can be suggested that acylphosphatase acts in vivo by regulating the cation transport in E. coli.

Acid Anhydride Hydrolases↗
PubMed1993

Chemical synthesis and expression of a gene coding for human muscle acylphosphatase.

A DNA sequence coding for human muscle acylphosphatase has been constructed using 16 chemically synthesized oligonucleotides. The 300-bases long DNA sequence has been cloned in the pT7.7 Escherichia coli expression vector and in the pYEpsec1 Saccharomyces cerevisiae expression vector. In both cases a high level of expression of acylphosphatase has been observed. The recombinant proteins have been purified to homogeneity and assayed in comparison with the natural protein, using benzoylphosphate as a substrate and phosphate as a competitive inhibitor. The recombinant enzymes expressed in the two microorganisms maintain the kinetic properties of the natural protein. In addition, NMR analysis shows that the gross fold of the two recombinant enzymes is correct.

Acid Anhydride Hydrolases↗
PubMed1993

The natural history of asymptomatic hepatitis B surface antigen carriers.

OBJECTIVE: To assess the long-term outcome in hepatitis B surface antigen (HBsAg) carriers who have normal liver function tests, focusing on survival and the development of severe liver disease and hepatocellular carcinoma. DESIGN: Cohort study with a mean follow-up of 130 months. SETTING: Liver clinic of a referral center. PATIENTS: Ninety-two HBsAg-positive blood donors with normal liver function tests. MEASUREMENTS: Histologic evaluation of liver specimens at baseline; clinical, biochemical, and serologic follow-up; and repeat liver biopsy if clinically indicated or after 10 years of follow-up. RESULTS: At baseline, 69 subjects had normal histologic findings or only minor abnormalities, 18 had chronic persistent hepatitis, and 5 had mild chronic active hepatitis. Serum enzyme levels remained normal in 58 of 68 patients who had regular follow-up. Three patients had biochemical changes consistent with hepatitis B virus (HBV) infection; in one of these patients, a later histologic evaluation showed progression to chronic active hepatitis. One patient developed alcoholic cirrhosis. Six other patients had mild or transient transaminase elevations, with no evidence of HBV replication, hepatitis D virus infection, hepatitis C virus (HCV) infection, or histologic deterioration. Liver histologic findings also remained unchanged in 21 patients who showed no biochemical changes during 10 years of follow-up and consented to have repeated liver biopsy. Ten patients showed loss of HBsAg; 2 of these patients acquired antibody to hepatitis B surface antigen (anti-HBs). All patients who did not have regular follow-up, except 1, were interviewed by telephone during 1990: All denied having liver disease. No patients developed hepatocellular carcinoma. CONCLUSIONS: Italian HBsAg carriers with initially normal liver function tests have an excellent prognosis: Delta superinfection is infrequent and the risk for developing hepatocellular carcinoma is low.

Adult↗
PubMed1992

Changes of IgG-bearing cell populations in the portal tracts of patients with chronic liver disease of viral etiology: an evaluation by immunoperoxidase method and computerized image analysis.

Little is known about the distribution of IgG-bearing cell subpopulations in normal liver and their possible changes in disease conditions. We developed an immunohistochemical method that proved suitable and accurate for the identification and characterization of IgG-bearing cells and their subpopulations in liver specimens. The method uses specific monoclonal antibodies on serial mirror liver sections. We applied this method to four normal liver tissue specimens and 25 liver biopsy samples of chronic hepatitis of viral etiology. Only rare IgG-bearing cells could be observed in the portal tracts of normal liver specimens. In contrast, a dense infiltrate of such cells was seen in liver specimens from patients with chronic viral hepatitis. The density of IgG-bearing cells in such patients ranged from 6 to 20 cells x 10(-4) micron2 in the different specimens (mean = 11 x 10(-4) micron2). The increase in IgG-bearing cells did not appear to be related to the histological diagnosis, to the degree of histological inflammatory activity or to the type of viral infection. The major population of IgG-bearing cells consisted of IgG1-positive cells (68%); IgG2- (17%), IgG3- (8%) and IgG4 (7%)-bearing cells represented only minor fractions. The increased prevalence of IgG1-bearing cells observed in chronic hepatitis but not in normal liver specimens suggests that these findings may reflect an activation of antibody production directed toward viral antigens or antigenic structures of self. The identification of the antigenic specificities of the antibodies produced by IgG-bearing cells might provide important clues in understanding the pathogenesis of chronic viral hepatitis.

Biopsy, Needle↗
PubMed1992

Detection of liver involvement in inflammatory bowel disease by abdominal ultrasound scan.

Fifty patients with ulcerative colitis, 24 with Crohn's disease, and 50 controls were studied by liver function tests and abdominal ultrasound scan. Twenty-two percent of ulcerative colitis patients, 29% of Crohn's disease patients, and none of the controls showed abnormal liver function tests. All subjects with abnormal liver function tests also had changes in ultrasound liver scan, consisting of hepatomegaly and/or a dysechoic liver echo pattern. Furthermore, the same ultrasound changes were observed, in the absence of any liver function test abnormalities, in 58% of ulcerative colitis patients, 50% of Crohn's disease patients and 6% of controls (P less than 0.0005, inflammatory bowel disease versus controls). Overall, some evidence of liver involvement, as judged by abnormal liver tests and/or abnormal ultrasound liver scan, was detected in about 80% of inflammatory bowel disease patients. Six patients with minor abnormalities of liver function tests underwent liver biopsy and 5 of them had pericholangitis. Ultrasound liver scan may provide a useful tool to evaluate the occurrence of liver involvement in inflammatory bowel disease patients.

Adolescent↗
PubMed1992

Familial aggregation of inflammatory bowel disease in northern Italy: a multicenter study. The Gruppo di Studio per le Malattie Infiammatorie Intestinali (IBD Study Group).

To assess the familial aggregation of inflammatory bowel disease (IBD) in Italy, the family pedigrees of 411 patients with ulcerative colitis (UC) and 241 patients with Crohn's disease (CD) seen at 14 participating hospitals were studied. Sufficient information was obtained on 97% of 3752 first-degree relatives, 80% of 8869 second-degree relatives, and 74% of 5791 cousins. Thirty-six propositi (5.52%) had a total of 44 affected relatives (16 CD, 28 UC). The prevalence of IBD was higher in first- than in second-degree relatives and cousins (791, 112, and 163 in 100,000, respectively). A strong intrafamilial disease concordance was observed, with 26 cases of UC and 6 of CD among relatives of UC patients and 10 cases of CD and 2 of UC among relatives of CD patients. The prevalence of UC among first-degree relatives of UC patients and that of CD among first-degree relatives of CD patients was 680 and 531 in 100,000, respectively. In conclusion, there is a high degree of familial aggregation for IBD in Italy, with a strong intrafamilial disease concordance.

Adolescent↗
PubMed1992

Increased jejunal intraepithelial lymphocytes bearing gamma/delta T-cell receptor in dermatitis herpetiformis.

T-cell receptor 1 (gamma/delta) expression was studied in 19 jejunal or duodenal specimens from patients with dermatitis herpetiformis and in 16 jejunal or duodenal specimens showing normal histology. In normal specimens, gamma/delta+ cells represented 10.8% of intraepithelial CD3+ lymphocytes. Around 50% of these cells were recognized by the A13 monoclonal antibody, which detects products of the V gamma 1/V delta 1 gene rearrangement and the non-disulfide-linked form of T-cell receptor 1. The remaining 50% reacted with the BB3 monoclonal antibody, which recognizes products of the V gamma 9/V delta 2 rearrangement and the disulfide-linked form of receptor. Very few gamma/delta+ cells were observed in the lamina propria. In jejunal specimens from patients with dermatitis herpetiformis, a significant increase in the prevalence of gamma/delta+ intraepithelial lymphocytes was observed (P less than 0.001). This finding was largely accounted for by an increase in those cells recognized by the A13 monoclonal antibody, thus possibly expressing the V gamma 1/V delta 1 rearrangement and the nondisulfide-linked form of receptor. These data suggest that similar pathogenetic mechanisms may be active in determining the jejunal damage in celiac disease and dermatitis herpetiformis.

Animals↗
PubMed1992

Mr 40,000 human colonic epithelial protein expression in colonic mucosa and presence of circulating anti-Mr 40,000 antibodies in cotton top tamarins with spontaneous colitis.

Saguinus oedipus, Callithrix jacchus, and Saguinus fuscicollis are three species of New World monkeys which develop a form of colitis that is similar to human ulcerative colitis. Only S oedipus, however, develop colon cancer. We examined intestinal tissues from these animals for the presence of an antigen cross reacting to the Mr 40,000 human colonic epithelial protein that acts as an autoantigen in ulcerative colitis. Using an anti-Mr 40,000 monoclonal antibody (7E12H12, IgM isotype), by an immunoperoxidase assay we showed that all colon specimens from S oedipus reacted with 7E12H12; however, the colonic tissue from C jacchus and S fuscicollis did not. In immunotransblot analysis eluted IgG antibody bound to human ulcerative colitis colon (CCA-IgG) reacted with Mr 40,000 protein(s) present in the extracts of colon from S oedipus animals and humans. Small intestinal tissue reacted neither with 7E12H12 nor with CCA-IgG. In S oedipus, the Mr 40,000 protein was localised exclusively to colonic epithelial cells. Preincubation of seven S oedipus colon specimens with eight of 10 sera from animals with acute or chronic colitis and 0 of four sera from animals without colitis almost completely inhibited the binding of 7E12H12 to the colonic epithelium. Four of these 10 sera inhibited the binding of 7E12H12 to the autologous colon. These results show the presence of circulating autoantibodies in S oedipus with colitis against an epitope(s) on Mr 40,000 protein shared by human and S oedipus colon.

Animals↗
PubMed1991

Risk of thromboembolic complications in patients with inflammatory bowel disease. Study of hemostasis measurements.

A large number of hemostasis measurements complications were performed in 20 patients with inflammatory bowel disease; whose changes have been associated with an increased risk of thromboembolic. Of the 20 patients, 9 (45%) had one or more changes suggestive of activation of the hemostatic system. Such changes were more frequently observed in patients with active disease. Two patients had changes in the fibrinolytic system (high plasminogen activator inhibitor-1 levels) and 2 in the natural anticoagulants (low antithrombin III activity). Nine patients had increased plasma fibrinogen levels and 6 patients had slightly increased levels of anticardiolipin antibodies. Most of the changes observed were not related to the type, location or activity of the disease. These data show that various biochemical abnormalities may be found in patients with inflammatory bowel disease, which may account for their increased risk of thrombosis, and suggest that multiple mechanisms may interact in determining such complications.

Adult↗
PubMed1990

A shared and unique epitope(s) on human colon, skin, and biliary epithelium detected by a monoclonal antibody.

An immune-complex-mediated inflammation has been suggested in the pathogenesis of skin and biliary complications in ulcerative colitis, although specific antigen-antibody complexes have not been found. We recently identified an Mr 40,000 colonic protein that reacts with tissue-bound immunoglobulin G eluted from colon specimens of patients with ulcerative colitis and not with immunoglobulin G eluted from colon specimens of patients with other diseases (J Clin Invest 1985;7:311). Murine monoclonal antibodies to the purified Mr 40,000 colonic protein are developed. The presence of the Mr 40,000 protein was examined with a monoclonal antibody (7E12H12, immunoglobulin M isotype) by an immunoperoxidase assay against various human epithelial tissues (74 specimens) including colon, ileum, jejunum, duodenum, stomach, esophagus, pancreaas, liver, respiratory, urinary, and genital tracts. In addition, gall bladder, bile duct, hepatic ducts, skin, synovial membrane, and eye tissue were also examined for any cross-reactivity with 7E12H12 and another anti-Mr 40,000 monoclonal antibody (7E6A5, immunoglobulin G1 isotype). 7E12H12 reacted only with colonic-epithelial cells mainly along the basolateral domains of plasma membrane and apical areas. The reactivity was present in both adult and fetal colon including the appendix. Among all the noncolonic tissue specimens, 7E12H12 reacted only with the gall bladder, the bile duct, the hepatic ducts, and the skin. All other epithelial tissues from 15 different organs, including the small intestine, synovium, and eye tissue, did not react. In the skin and biliary tract the immunoreactivity was exclusively present in the epidermal epithelial cells and mucosal epithelium respectively. 7E6A5 stained colonic mucosal cells but did not react with skin, biliary epithelium, synoyium and eye tissue. These results indicate the presence of a unique epitope or epitopes on Mr 40,000 colonic epithelial protein that is shared by the skin and biliary tract epithelial cells. Future studies of this shared epitope or epitopes and its immune recognition may provide further understanding in the pathogenesis of extraintestinal complications involving these organs in patients with ulcerative colitis.

Antibodies, Monoclonal↗
PubMed1990

Hybridomas using athymic nude mouse injected with Crohn's disease (CD) tissue filtrate. Immunoreactivity of the hybridomas with CD sera.

Injections of Crohn's disease (CD) tissue filtrates produce lymphoma and hyperplastic lymph nodes from plasma cell hyperplasia (PCH) in athymic nude (nu/nu) mice; these lymphoid tissue contain an antigen(s) recognized by CD serum/gamma G immunoglobulin (IgG). To immortalize the "CD-reactive antigen(s)," the authors fused the lymphoid cells from a CD tissue filtrate primed nu/nu mouse with nonsecretory mouse myeloma cells. Hybrids were screened and selected based on their reactivity with CD serum IgG, but not with control serum IgG in an indirect immunofluorescence assay (IF). Two CD-positive hybridomas were examined by IF with sera from 47 CD, 38 ulcerative colitis (UC), 13 controls with other gastrointestinal diseases, 19 with autoimmune diseases, and 21 normal subjects. Sera from 16 CD patients (34%) reacted with the two hybridomas, but only one of 38 UC sera and none of the 53 other disease or normal control sera reacted. The immunoreactivity of CD sera was significantly higher than UC sera (P less than 0.01) and each of the other groups (P less than 0.007). Using immunoperoxidase techniques at light and electron microscopic levels, the authors localized CD-associated antigen(s) in the plasma membrane of the two hybridomas. Further characterization of these hybridomas and the immunoreactive protein(s) may provide an important probe(s) for the diagnosis and the understanding of the pathogenesis of CD.

Animals↗