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Biomedical subjects

M Lenzi

Publications and source records attributed to M Lenzi.

At least 91 records · Page 5Linked to original sources
PubMed1987

A renin-secreting tumor.

A 23-year-old white male was referred for hypertension resistant to triple antihypertensive treatment, with hypokalemia, hyperaldosteronism and elevated levels of circulating plasma renin activity (PRA). Renal angiography and echoscans put in evidence an avascular solid mass at the midlower level of the right kidney. Renal vein catheterization with sampling of blood from the lower branches of the right renal vein showed lateralization of renin secretion from that side. After surgical exeresis, the mass (1.0 cm) was diagnosed as a renal hemangiopericytoma on the basis of light and electron microscopy. Tumor exeresis was followed by a prompt normalization of blood pressure and plasma potassium, with a decrease in PRA and aldosterone. Two months after surgery the patient was still normotensive. Circulating levels of inactive (trypsin-activable) renin were around 60% of the total pool of plasma renin, i.e. much lower than those reported in other cases of renin-secreting tumors. After surgery, inactive and active renin fell in parallel, implying that both were secreted by the tumor. Tumoral PRA responded to postural stimulation, but was unresponsive to acute converting enzyme inhibition, suggesting that sympathetic stimuli were still operative, but the negative feedback inhibition by angiotensin II on renin secretion was lost. Acute converting enzyme inhibition by captopril dropped blood pressure; however, during long-term treatment, the drug (3 X 50 mg/day) was ineffective in terms of either blood pressure normalization or relief of secondary hyperaldosteronism. Acute calcium entry blockade by nifedipine (10 mg p.o.) caused an evident blood pressure drop.

Adult↗
PubMed1987

Precipitating antibodies to rabbit thymus extractable antigens in chronic liver disease: relationship with anti-actin antibodies.

Using counterimmunoelectrophoresis (CIE), serum antibodies to rabbit thymus extractable antigens were detected in 15% (38/259) of patients with chronic liver disease (CLD) of various aetiologies and 33% (41/124) of patients with miscellaneous connective tissue diseases (CTD). A remarkable diversity of precipitating systems was apparent among cases with the two classes of disorders. All the five systems found in CLD (XR, XR2, SS-B, XR3, XR4) were associated mostly with immunological hepatic disorders. In the 52 autoimmune hepatitis cases, XR was mainly detected (29%), whereas in the 82 primary biliary cirrhosis patients the whole spectrum of reactivities was represented (XR: 11%, XR2: 10%, SS-B and XR3: 2% each, XR4: 1%). XR proved to be closely associated with smooth muscle antibodies (SMA, detected by indirect immunofluorescence on rat kidney sections) both qualitatively and quantitatively. Since all SMA positive sera with anti-actin specificity (SMAT, SMAG) were XR positive and purified actin could absorb out XR CIE reactivity, the hypothesis is made that a cross-reaction occurs between XR antigen and actin epitope(s).

Actins↗
PubMed1987

Construction of a continent perineal colostomy by using electrostimulated gracilis muscles after abdominoperineal resection: personal technique and experience with 32 cases.

A series of 32 patients operated on for rectal carcinoma is reported. A new technique by using the gracilis muscles to reconstruct a functional anal sphincter after abdominoperineal resection was performed. No operative mortality was recorded. Functionality of the new sphincter was guaranteed by electromyostimulation. Electrostimulation has been useful in both increasing the muscular trophic level and in improving the postoperative bio-feedback. Perineal infection was recorded in 9 patients being the most common complication although it did not compromise the functionality of the new sphincter. In one case acute colonic ischaemia was treated by resection and definitive left colostomy. 17 out of the 27 patients in which a functional follow-up was obtained, scored a "very good" continence to stool and flatus while in 6 patients occasional episodes of incontinence to liquid stool are referred. Local or distant metastases presented in 6 patients. The obtained results encourage in continuing the research with this technique in the attempt to reduce the number of patients that must pay the high price of a definitive abdominal colostomy for cure.

Adenocarcinoma↗
PubMed1987

Immune dysfunction in primary biliary cirrhosis (PBC): I. Increased sensitivity of PHA stimulated lymphocyte cultures to indomethacin.

A reduced responsiveness of peripheral blood lymphocytes from PBC patients to phytohaemagglutinin (PHA) was observed. Such an alteration may be related either to an intrinsic defect of T cells to proliferate or to a derangement of endogenously secreted mediators with regulatory functions, i.e., prostaglandins (PG). The role of the PG mediated suppressor system in 14 PBC patients and in 12 age and sex matched controls was evaluated. After the addition of indomethacin, the lymphocyte responsiveness to PHA increased in both controls and in PBC patients. However, this increment was statistically significantly only in PBC patients. The addition of PGE1 and PGE2 to PHA stimulated cultures decreased the lymphocyte proliferative activity. No differential sensitivity to PGEs was detectable in lymphocytes from PBC patients. Our data suggest, that, after polyclonal stimulation, mononuclear cells from PBC patient may release increased levels of PGEs which in turn affect the proliferative activity of mitogen activated lymphocytes.

Adult↗
PubMed1986

Antibodies to dietary antigens in coeliac disease.

Antibodies to gliadin (AGA) were found in 77 (94%) of 82 sera from patients with active coeliac disease (untreated and after gluten challenge). Although IgG AGA had a higher nosological sensitivity than IgA AGA (88% versus 67%), their nosological specificity was lower than that of IgA antibodies (87% versus 100%). The sensitivity of antibodies to casein, beta-lactoglobulin, and ovalbumin in active coeliac disease varied from 36% to 48% without significant difference between IgG and IgA antibodies. IgG and IgA antibodies to milk and egg proteins showed a specificity similar to that of AGA, although some IgA antibodies other than AGA were found in disease controls (Crohn's disease, ulcerative colitis, post-enteritis syndrome).

Adolescent↗
PubMed1985

Mechanically isolated hepatocytes are unsuitable to detect antibodies directed against plasma membrane determinants.

The ultrastructural morphology of mechanically and enzymatically isolated hepatocytes was compared. Plasma membrane integrity was evaluated by electron microscopy, both in the absence and in the presence of ruthenium red, which stains cell coat glycoproteins and makes it possible to identify even partially permeable cells, and by indirect immunofluorescence using experimental antibodies directed against epithelial submembranous components (prekeratin, actin). In order to evaluate the antigenic integrity of the hepatocellular plasma membrane after the isolation procedures, an immuno-electronmicroscopical technique (Staph. pA-colloidal gold) was applied using the IgG fraction from two liver-kidney microsomal antibody (LKM) positive sera, known to react with both plasma membranes and smooth endoplasmic reticulum (SER). Enzymatic procedure made it possible to isolate hepatocytes with a good preservation of both plasma membranes and subcellular organelles. Ruthenium red staining was confined to plasma membranes, thus indicating the preservation of both cell-coat glycoproteins and plasma membrane. Most cells were negative after exposure to experimental antibodies. After exposure to LKM positive sera colloidal gold was strictly confined to the plasma membrane. On the other hand, mechanically isolated hepatocytes showed wide interruptions of the plasma membrane and gross alterations of subcellular organelles. Most cells were stained by ruthenium red, thus confirming the plasma membrane permeability. In addition, a linear peripheral positivity was found in the vast majority of the cells tested with anti-prekeratin and anti-actin antibodies. LKM-colloidal gold complexes were found at the level of both residual plasma membrane and SER.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗
PubMed1985

Antibodies to gliadin detected by immunofluorescence and a micro-ELISA method: markers of active childhood and adult coeliac disease.

Antibodies to gliadin have been detected by immunofluorescence (IFL-AGA) and a micro-ELISA method (ELISA-AGA) in 45 out of 47 (96%) sera from patients with active childhood and adult coeliac disease. The two methods were more sensitive than R1-reticulin antibodies (R1-ARA) which were found only in 28 of the same patients (60%). R1-ARA were always negative in the 26 sera from patients with childhood coeliac disease and adult coeliac disease after gluten free diet, while IFL- and ELISA-AGA were respectively found in three (12%) and in four (15%) out of these patients. Moreover, while R1-ARA and IFL-AGA were strictly confined to coeliac disease. ELISA-AGA were occasionally found in patients with control diseases. These 'false positive' antibodies were all of IgG class and had low titres. In our experience IFL- and ELISA-AGA of IgA class were strictly confined to active childhood coeliac disease and adult coeliac disease. The detection of AGA is useful in monitoring the diet and in the follow up of coeliac disease. IFL- and ELISA-AGA, then, are to be preferred to R1-ARA for the screening of coeliac patients.

Adult↗
PubMed1985

Immunomorphological characterisation of antinuclear antibodies in chronic liver disease.

Two immunofluorescence procedures to evaluate antinuclear antibodies were compared in a series of 221 patients with chronic liver disorders of various aetiologies. The use of HEp-2 cells allowed us to discriminate with more confidence between the homogeneous and speckled patterns, to show the presence of associated patterns in the same serum, and, above all, to identify two specificities, unrecognizable on tissue sections. The anticentromere antibody was found in 10% of cases of primary biliary cirrhosis and occasionally in other conditions; the antibody staining multiple nuclear dots was strictly confined to primary biliary cirrhosis (17%). With the exception of autoimmune chronic active hepatitis the prevalence of antinuclear antibodies increased in all groups, particularly in primary biliary cirrhosis. Homogeneous antinuclear antibody was associated by both immunofluorescence procedures with autoimmune chronic active hepatitis. The multiple nuclear dot antinuclear antibody turned out to be an additional marker of primary biliary cirrhosis, helpful for the positive diagnosis of primary biliary cirrhosis in a proportion of cases negative for antimitochondrial antibody. Absorption experiments showed that multiple nuclear dot and antimitochondrial antibody are antigenically distinct. Moreover, multiple nuclear dot antinuclear antibody was associated with the finding of a dry Schirmer's test.

Antibodies, Antinuclear↗
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

Liver cell surface expression of the antigen reacting with liver-kidney microsomal antibody (LKM).

To test the hypothesis that liver membrane antibodies, found in all liver-kidney microsomal antibody (LKM) positive sera from patients with chronic active hepatitis, were directed against antigens shared by both hepatocellular endoplasmic reticulum and plasma membranes, absorption experiments have been performed using viable isolated hepatocytes and liver microsomes as antigens. Results are in agreement with the above hypothesis, LKM, which displays a restricted organ specificity, is thus able to react with antigenic determinants expressed on the liver cell surface, as it has been demonstrated for strictly organ specific antibodies directed against thyroid, adrenal and gastric parietal cell microsomes.

Animals↗