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Biomedical subjects

M Vecchi

Publications and source records attributed to M Vecchi.

At least 91 records · Page 5Linked to original sources
PubMed1989

Evidence of altered structural and secretory glycoconjugates in the jejunal mucosa of patients with gluten sensitive enteropathy and subtotal villous atrophy.

The pattern of lectin histochemistry in formalin fixed, paraffin embedded normal jejunal and subtotal villous atrophy specimens from patients with gluten sensitive enteropathy were compared. There was no significant difference in the binding pattern of five lectins (Arachis hypogaea, Canavalia ensiformis, Lens culinaris, Phaseolus vulgaris and Triticum vulgaris) between normal and abnormal specimens. There were significant changes in the binding pattern of three lectins (Dolichos biflorus, Ulex europaeus, Ricinus communis), with special reference to goblet cells staining. These changes were present in all the specimens studied, regardless of the clinical diagnosis of dermatitis herpetiformis or coeliac disease. Dolichos biflorus reactive goblet cells were significantly decreased (p less than 0.001) in abnormal tissue and confined to the luminal edge of the mucosa. Strong reactivity of goblet cells in abnormal tissue was recorded with Ricinus communis and Ulex europaeus, lectins that bind to few or no goblet cells in normal tissue. These findings show that modifications of structural and secretory glycoconjugates occur in the jejunal mucosa of patients with gluten sensitive enteropathy.

Atrophy↗
PubMed1988

Comparison between enzyme-linked immunosorbent and I.F. assays in the serological diagnosis of HIV infections.

A rapid, sensitive indirect immunofluorescence assay based on the use of acetone-fixed virus producing MOLT T4/LAV cells was adapted for the detection of anti-HIV antibodies. At the same time, 1486 serum samples, collected by the AIDS Surveillance and Study Centre of Modena, were tested by ELISA and IFA: the percentage of agreement of both assays was of 99.66%. Such datum suggested that IFA could be used as a serological assay for screening and confirmatory purposes.

Acquired Immunodeficiency Syndrome↗
PubMed1987

The production and characterization of monoclonal antibodies to a human colonic antigen associated with ulcerative colitis: cellular localization of the antigen by using the monoclonal antibody.

We detected in human colon extracts a 40 kDa protein(s) that specifically reacts with tissue-bound IgG obtained from the colon of patients with ulcerative colitis or CCA-IgG. Using the hybridoma technology, we developed monoclonal antibodies to this 40 kDa protein. The specific immunoreactivity of one of the monoclonal antibodies (7E12H12, IgM isotype) against the 40 kDa protein was demonstrated both by ELISA and by immunotransblot. Competitive binding experiments showed that CCA-IgG inhibits the binding of 7E12H12 to the 40 kDa protein, suggesting the recognition of common epitope(s) on the 40 kDa protein by the monoclonal antibody and CCA-IgG. 7E12H12 was used to determine cellular localization of the 40 kDa protein. Biopsy tissue specimens from colon, esophagus, stomach, duodenum, jejunum, ileum, liver, pancreas, lungs, kidneys, salivary, and mammary glands were obtained. Tissue specimens were fixed in 4% paraformaldehyde or in 10% formalin. Sections were sequentially incubated with the hybridoma supernatant, biotinylated anti-mouse IgM, avidin-biotin-peroxidase complex, and 3,3'-diaminobenzidine. An unrelated hybridoma supernatant was used as control. The monoclonal antibody exclusively recognized colonic epithelial cells both in the crypt and on the luminal surface. Immunoreactivity was present on the plasma membrane chiefly along the basolateral areas of the cells. Plasma membrane localization of the 40 kDa protein was confirmed by immunoelectron microscopy. All colonic mucosal biopsy specimens from both adult and fetal colon reacted with the monoclonal antibody. None of the biopsy specimens from stomach, duodenum, jejunum, ileum, liver, pancreas, or non-gastrointestinal tissue reacted with the antibody, confirming the organ specificity of the 40 kDa protein. The interaction between this colonic epithelial membrane protein and the CCA-IgG may play an important role in the pathogenesis of ulcerative colitis.

Antibodies, Monoclonal↗
PubMed1987

Evaluation of structural and secretory glycoconjugates in normal human jejunum by means of lectin histochemistry.

The labelling pattern of eight lectins was studied in jejunal samples from ten normal subjects, in order to define the normal distribution of structural and secretory glycoconjugates in the small bowel. The following lectins were studied by means of a peroxidase technique on formalin-fixed samples: Arachis hypogaea, Ricinus communis, Canavalia ensiformis, Lens culinaris, Phaseolus vulgaris, Triticum vulgaris, Ulex europaeus, Dolichos biflorus. Phaseolus vulgaris reacted with goblet cell mucus throughout the villus-crypt axis. Conversely Ulex europaeus, Dolichos biflorus and Triticum vulgaris lectin labelling of goblet cells appeared to be confined to the upper part of the villi. This finding suggests that during cell migration from crypt to villus tip, the continuing maturation of goblet cells is associated with the differentiation of secretory carbohydrates, which probably parallels the cell maturation cycle. Lectin histochemistry appears to be a reliable tool for the study of structural and secretory glycoconjugates in the jejunal mucosa, and might be of value in the study of diseases in which the cell-maturation cycle in the small bowel is altered.

Concanavalin A↗
PubMed1987

Development of a monoclonal antibody specifically reactive to gastrointestinal goblet cells.

A mouse monoclonal antibody (7E6A5) of IgG isotype, reacting specifically with mucin-producing goblet cells of the human gastrointestinal tract, has been developed. 7E6A5 reacts by an ELISA with colonic protein eluted from a DEAE column. A screening by immunoperoxidase assay of 76 specimens from 19 different human tissues showed that the immunoreactivity of 7E6A5 was confined exclusively in the globules of goblet cells in the colon, the appendix, and the small intestine. Nongoblet small and large intestinal epithelial cells did not react. Immunoelectron microscopy demonstrated the reactivity with mucin droplets in a homogeneous granular pattern inside the globules of goblet cells. Mucus-secreting cells from remaining parts of the gastrointestinal tract and other mucus-secreting organs such as respiratory, genitourinary tracts, salivary and mammary glands did not show any reactivity to 7E6A5. These findings indicate that the antigen recognized by 7E6A5 is shared by the goblet cells of both the small and large intestines and is unique to them. The monoclonal antibody may be useful in the study of function of mucus-secreting goblet cells and may represent an important tool in the evaluation of diseases such as ulcerative colitis, colon cancer, and intestinal metaplasia in gastric mucosa that are associated with quantitative changes in goblet cell numbers or with qualitative differences in mucin secretion.

Antibodies, Monoclonal↗
PubMed1987

Activation of coagulation in cirrhotics after endoscopic variceal schlerotherapy.

To investigate the occurrence and extent of activation of coagulation after endoscopic variceal sclerotherapy (EVS), we performed serial measurements of conventional coagulation tests [prothrombin time (PT), partial thromboplastin time (PTT), platelets, and fibrinogen], and of plasma fibrinopeptide A (FPA) in 39 cirrhotic patients undergoing 55 sessions of elective EVS. Thrombin (20 U/ml) and sodium morrhuate 5% were used in sequence as sclerosants on 34 occasions. In the remaining 21 sessions, sodium morrhuate 5% alone was used. Conventional coagulation tests did not change significantly after EVS, regardless of the type of treatment. Basal plasma FPA levels were abnormally high in about 50% of patients. After EVS, plasma FPA increased sharply in 37/39 patients (95%), returning to baseline values in most of them within 24 h. We conclude that transient systemic activation of blood coagulation occurs after EVS. Such activation can be detected only by sensitive methods such as FPA assay, and has no effect on conventional coagulation tests. This, and the absence of any clinical EVS-related coagulation disorder in our patients, suggests that activation of coagulation should not be a major concern for patients undergoing EVS.

Adult↗
PubMed1986

A freeze-fracture study of the enteropathy associated with dermatitis herpetiformis: a comparative investigation with coeliac disease.

Jejunal biopsies from patients with either dermatitis herpetiformis or coeliac disease were freeze-fractured and compared with normal jejunal biopsies. The intestinal mucosa of the normal biopsies showed a normal structure, with well-developed and tightly packed microvilli; in dermatitis herpetiformis and coeliac disease degenerative changes of the intestinal mucosa occurred. These changes appeared to be segmental in dermatitis herpetiformis and diffuse in coeliac disease. Emphasis is placed on changes in the tight junctional net at the base of the microvilli, which could represent cellular damage related to increased intestinal permeability to macromolecules in these diseases. An interpretative hypothesis for these observations is presented.

Biopsy↗
PubMed1986

Stereoisomers of alpha-tocopheryl acetate. IV. USP units and alpha-tocopherol equivalents of all-rac-, 2-ambo- and RRR-alpha-tocopherol evaluated by simultaneous determination of resorption-gestation, myopathy and liver storage capacity in rats.

Whereas the alpha-tocopheryl acetate (alpha-TA) stereoisomers have frequently been compared in various vitamin E tests, only little studies have been made on the free alpha-tocopherols. For this reason, comparative tests of the alpha-tocopherol (alpha-TOH) stereoisomers were made by means of the resorption-gestation method, not only individually but also against the USP standard all-rac-alpha-TA. In some of these tests, the parameter resorption-gestation was supplemented by determination of pyruvate kinase (PK) activity as well as by measurement of the vitamin E level in the liver. Quantitative statistical evaluation of the results was made by weighted probit analysis or by symmetrical parallel line assays. Comparison of all-rac-alpha-TOH (dl-alpha-TOH) with RRR-alpha-TOH (d-alpha-TOH) in the resorption-gestation test revealed an activity ratio of 1:1.38. Compared with 2-ambo-alpha-TOH, RRR-alpha-TOH was more active by a factor of 1.34 (resorption-gestation) or 1.45 (myopathy). On account of its great importance in practice, the comparison between RRR-alpha-TOH and the USP standard was repeated three times. With the parameters resorption-gestation and myopathy, mean activities on a weight basis of 0.69 and 0.74, respectively, were measured. These results fail to confirm the established activity of 1 mg RRR-alpha-TOH = 1.49 USP units. If vitamin E activity is to be given in alpha-tocopherol equivalents (alpha-TE), the values are referred to RRR-alpha-TOH and the calculation is made with their reciprocals. Depending on the parameter used, the activity of 1 mg all-rac-alpha-TA was equivalent to 1.45 alpha-TE (resorption-gestation) or 1.35 alpha-TE (myopathy) and was thus noticeably higher than the established value of 0.67 alpha-TE. For the first time, three parameters were determined simultaneously in the comparison of all-rac-alpha-TOH with the USP standard. Quantitative evaluation yielded the following activities: Resorption-gestation, 0.52; Myopathy, 0.63; liver storage, 0.68. The currently accepted value of 1.10 USP units for 1 mg all-rac-alpha-TOH was thus not even reached approximately. In the light of our experimental findings as well as of those of other laboratories, the activities of the alpha-tocopherol stereoisomers expressed in USP units and of their esters expressed in alpha-tocopherol equivalents need to be corrected.

Animals↗
PubMed1986

Nutritional status, function of the small intestine and jejunal morphology after total gastrectomy for carcinoma of the stomach.

We studied the nutritional status and the prevalence of malabsorption in 12 patients one to three years after total gastrectomy (TG) for gastric neoplasm. The Roux-en Y technique was used for reconstruction. A correct dietary regimen according to the recommended daily allowance was suggested and patients were seen quarterly on an out patient basis. The nutritional status was evaluated by measuring serum albumin levels, total iron binding capacity, cholinesterase, area muscular circumference, triceps skinfold and delayed hypersensitivity response. Work-up studies for the small intestine included: stool fat, D-xylose and glucose tolerance tests, Schilling test (phase II and III), serum iron levels, serum vitamin B12 levels and biopsy of the jejunum. Malnutrition, defined as the occurrence of two or more abnormal nutritional parameters, was observed in one patient; glucose and D-xylose tolerance tests were normal in all. A mild degree of steatorrhea was observed in four patients. The second phase of the Schilling test was abnormal in eight patients, but urinary excretion of vitamin B12 increased in three of four patients after use of antibiotics. Low serum vitamin B12 levels were common after the twentieth postoperative month. Serum iron levels were initially low and returned to normal six months after TG. All patients had normal jejunal histologic findings. These data indicate that malnutrition after TG is not common if an adequate dietary intake is maintained. Malabsorption, possibly due to bacterial overgrowth, is not a major clinical problem.

Aged↗
PubMed1986

[Natural history of the state of asymptomatic carrier of HBsAg: 7-year follow-up].

UNLABELLED: Ninety-six chronic asymptomatic HBsAg carriers underwent liver biopsy. Liver histology was normal in 5 cases, showed nonspecific changes in 67, chronic persistent hepatitis in 18, and chronic-active hepatitis in 6. Seventy-four patients were followed for up to 105 months (mean 80 months) in order to evaluate the occurrence of clinical, biochemical, serological or histological changes. Only two patients cleared the HBsAg, respectively 10 and 96 months after undergoing liver biopsy; the latter patient became anti-HBs positive 6 months after he cleared HBsAg. All 10 patients who initially were negative for both HBeAg and anti-HBe became anti-HBe positive during follow-up. All 4 patients who were HBeAg positive at the time of liver biopsy cleared HBeAg 6 to 39 months thereafter. Two of them became anti-HBe positive. None of the patients initially HBeAg negative became positive for this antigen during follow-up. Significant increases of serum transaminases were observed in 5 patients; in one superinfection by delta agent was documented, the other 4 being constantly anti-delta negative. Three of the latter patients underwent repeat liver biopsy, which showed progression from minimal changes to chronic persistent hepatitis in one, and from minimal changes to chronic active hepatitis in another. In the third patient, repeat biopsy showed persistence of chronic persistent hepatitis. IN CONCLUSION: chronic hepatitis occurs in about 25% of chronic asymptomatic HBsAg carriers; clearance of HBsAg is a rare event among these patients; the HBe system has little diagnostic or prognostic value; delta superinfection is rare; however, deterioration of liver histology may occur even in the absence of delta superinfection.

Adolescent↗
PubMed1986

Biliary cystadenoma: an uncommon cause of recurrent cholestatic jaundice.

The clinical history of a patient with intermittent jaundice is presented. The diagnostic work up, including ultrasound, laparoscopy, and endoscopic retrograde cholangiography, revealed a multiloculated cystic mass in the left lobe of the liver. At laparotomy, a multicystic lesion invading the left hepatic duct and protruding into the common bile duct was found. Histological examination revealed a biliary cystadenoma. Complete excision is the treatment of choice of such lesions.

Adult↗
PubMed1985

In situ identification of immune competent cells in gastrointestinal mucosa: an evaluation by immunoelectronmicroscopy.

The in situ identification of lymphocyte subpopulations by means of immunopathological techniques using specific monoclonal antibodies provides a tool for the study of the gastrointestinal-associated lymphoid tissue (GALT) in health and disease. In this field, monoclonal antibodies have been applied previously using light microscopy and either immunofluorescence or immunoperoxidase; however, these techniques are not sensitive enough to allow precise evaluation of localization of labelling. We describe an immunoelectronmicroscopic method, which defines labelling specificity, since it allows the identification of cells by immunophenotype labelling and ultrastructural markers simultaneously. This in turn allows a better evaluation of the labelled cells and of the relationship between labelled and unlabelled cells. The main features of the method are the use of fresh tissue samples, fixing in paraformaldehyde CaCl2, and the coupling of the immune reaction to an amplification system (avidin-biotin-peroxidase complex). The technique yields a good preservation of cellular ultrastructure, together with a strong and specific immunolabelling. Our results confirm the high specificity of monoclonal antibodies when applied to immunopathology techniques. We confirm the pattern of distribution of various lymphocyte subsets in the jejunal mucosa described by other authors by light microscopy.

Antibodies, Monoclonal↗
PubMed1985

Stereoisomers of alpha-tocopheryl acetate. III. Simultaneous determination of resorption-gestation and myopathy in rats as a means of evaluating biopotency ratios of all-rac- and RRR-alpha-tocopheryl acetate.

The resorption-gestation test furnishes information on a more complex vitamin activity than is the case with other vitamin E tests, so that correspondingly more importance attaches to the results. A drawback is their questionable validity for species other than the small rodents in which fetal resorption has so far been observed. In the four experiments carried out, RRR-alpha-tocopheryl acetate (alpha-TA) was compared with all-rac-alpha-TA (USP standard) and a mean relative activity of 1.32 was determined. The additional measurement of pyruvate kinase (PK) activity serves to emphasize the correlation with nutrition-linked myopathy. This biochemical lesion is seen in various animal species and man. In two experiments, the parameters fetal resorption and plasma PK activity were measured together. For all-rac-alpha-TA and RRR-alpha-TA, the following activity ratios were calculated: Resorption-gestation 1:1.35; Myopathy 1:1.47. It could be shown that the two parameters are measurable quantitatively in a single experimental set-up and that the results are in good agreement. The accepted activity of 1 mg RRR-alpha-TA = 1.36 USP Units was fully confirmed.

Animals↗
PubMed1984

Antibodies to gliadin in adult coeliac disease and dermatitis herpetiformis.

Antibodies to gliadin, searched for by indirect immunofluorescence and a micro-ELISA, were detected in 16 (64%) of 25 sera from patients with adult coeliac disease and in 13 (45%) of 29 with dermatitis herpetiformis. Although the sensitivity of the two tests was relatively low in the whole groups, it increased when only cases with severe jejunum abnormalities were considered (93% for coeliac disease and 81% for dermatitis herpetiformis). A significant correlation was found between antigliadin antibodies and the severity of jejunum damage in both diseases. Moreover, most coeliac and dermatitis herpetiformis patients with antigliadin antibodies were on normal diet. The specificity of the tests was 100% for the immunofluorescence and fairly good for the micro-ELISA, as only 5 (11%) of the 46 disease control patients (Crohn's disease, ulcerative colitis) were positive for antigliadin antibodies. R1-reticulin antibody test was equally specific but less sensitive in both groups. We conclude that antigliadin antibodies are useful in the diagnosis of patients with active adult coeliac disease and dermatitis herpetiformis with gluten-sensitive enteropathy. Moreover, the two tests make it possible to monitor the compliance to gluten-free diet in both diseases.

Adolescent↗
PubMed1984

Acute type B hepatitis in parenteral drug-addicts (PDA): prognostic value of circulating HBsAg/IgM complexes.

Fifty-three parenteral drug-addicts with acute viral hepatitis type B were tested by a solid-phase radioimmunoassay for circulating HBsAg/IgM complexes in the acute phase and in the follow-up. Among the 47 recovered patients HBsAg/IgM complexes were either absent from the onset of the disease, or disappeared from serum within 4 weeks of admission, long before HBsAg had cleared or serum alanine aminotransferase has returned to normal. On the contrary, HBsAg/IgM complexes persisted indefinitely among the 6 patients who developed a chronic HBsAg-positive hepatitis. These results indicate that sequential serum testing for HBsAg/IgM complexes might be of value in predicting the long-term outcome of acute type B hepatitis of parenteral drug-addicts.

Acute Disease↗
PubMed1983

Small-bowel involvement in dermatitis herpetiformis and in linear-IgA bullous dermatosis.

In 23 patients with dermatitis herpetiformis (DH) and five patients with linear-IgA bullous dermatosis (BD), we evaluated the occurrence of histologic jejunal changes and small-bowel function abnormalities. None of the patients showed clinical signs or symptoms of malabsorption. Morphological jejunal changes consistent with gluten-sensitive enteropathy were found in 82% of DH patients and in 60% of BD patients. However, BD patients showed only mild jejunal histologic abnormalities, whereas more severe jejunal lesions were found in most patients with DH. Functional tests showed a rough correlation with the severity of the jejunal lesions, being almost completely normal in BD patients and DH patients with mild intestinal damage, whereas most of DH patients with subtotal or total villous atrophy showed abnormal d-xylose tests and folic acid assays. Lactose tolerance tests (H2 breath test and blood glucose after oral lactose load) showed no correlation with the degree of jejunal damage.

Adult↗
PubMed1982

Persistence of circulating HBsAg/IgM complexes in acute viral hepatitis, type B: an early marker of chronic evolution.

Serial serum samples from 110 patients with acute viral hepatitis type B were tested for HBsAg/IgM complexes by a newly developed solid-phase radioimmunoassay. In 102 patients the infection resolved and they recovered from the disease. In these patients, HBsAg/IgM complexes were either absent from the outset of disappeared from serum within four weeks of admission, long before HBsAg had cleared or serum alanine aminotransferase had returned to normal, 8 patients progressed to chronic HBsAg carrier state and chronic liver disease. In these patients, HBsAg/IgM complexes were detectable in the serum on admission, and never disappeared. These results indicate that persistence of circulating complexes containing HBsAg and IgM after the early phase of acute viral hepatitis type B is a predictor of disease chronicity. As early as the fifth week of illness those in whom chronic liver disease developed could be distinguished from those who recovered.

Adolescent↗