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Biomedical subjects

A Pisani

Publications and source records attributed to A Pisani.

At least 145 records · Page 8Linked to original sources
PubMed1990

Angioscintigraphic assessment of hemodynamic effects of penbutolol in cirrhotics with portal hypertension. A double-blind, randomized, controlled study.

This randomized double-blind controlled study analyzed the hemodynamic effects of penbutolol, a new levorotatory beta-blocker, using radionuclide angiography. Twenty cirrhotics with esophageal varices were randomized to two groups: 10 received 40 mg/day of penbutolol orally and the others placebo. Angioscintigraphy was performed before and after an 8-day treatment period. Three cases in the penbutolol group were lost due to software damage, hence the data of 17 patients were analyzed. The two groups were matched for age, sex, etiology of cirrhosis and hepatic function. The index of portal perfusion decreased significantly (-29%; p = 0.018) and the hepatic artery index increased significantly (+23%; p = 0.018), while no changes were observed after placebo. The heart rate decreased significantly after penbutolol (-9%; p = 0.028), while neither penbutolol nor placebo modified the ejection fraction. In conclusion, penbutolol decreased portal perfusion index (the compensatory increase in the hepatic artery index confirmed this change) without major modification of total hepatic blood flow or systemic hemodynamics. Angioscintigraphy is reasonably accurate, reproducible, safe and can be considered suitable for routine use in the assessment of liver hemodynamics.

Double-Blind Method↗
PubMed1990

Emergency portosystemic shunt in patients with variceal bleeding.

Thirty-five patients for whom emergency sclerotherapy or conservative treatment, or both, failed to arrest variceal bleeding, or who had early rebleeding and required emergency portosystemic shunts (EPSS) were studied. EPSS permanently controlled the variceal bleeding in all but one patient. In this patient, the shunt was patent as demonstrated by angiography. Esophageal varices disappeared in 18 patients and were reduced in 14. Three patients died before the endoscopic examination could be performed. The causes of death were hepatic failure in two and bleeding ulcerations of the gastric fundus in the other patient. One patient was classified in Child's category B and two in Child's category C. Thirty-two patients submitted to EPSS and were discharged alive. Twelve of these patients subsequently died, at an average of 11.2 months after undergoing the shunt procedure. Four of 12 patients died of hepatic failure; two patients died of hepatomas; two, other neoplasia; three, hemorrhaging duodenal ulcers, and one patient, renal failure. Analysis of actuarial survival rates showed that the five year survival rate was 43 per cent. The long term survival rates were fewer for patients with Child's category C than for those with combined Child's categories A and B (five year survival rates were 21 versus 55 per cent; p less than 0.05). During the follow-up period, none of the patients had variceal bleeding. Chronic encephalopathy developed in six, which was mild in three, moderate in one instance and severe in two. It developed soon after EPSS, with onset in the first month after discharge in three. Thus, when conservative treatment fails to arrest variceal bleeding, EPSS should be performed to guarantee definitive control of hemorrhage and prolong the survival period.

Cause of Death↗
PubMed1989

Decline in the exposure to hepatitis A and B infections in children in Naples, Italy.

In May 1988, the hepatitis A antibody (anti-HAV) and hepatitis B virus (HBV) markers were studied by radioimmunoassay in 484 apparently healthy children between the ages of 7 and 12, attending a primary school in Naples, Italy. The overall anti-HAV prevalence was 11.2%, increasing from 5.2 in 7-year-old children to 28.2% in children between the ages of 11 and 12 years old. The overall prevalence of the hepatitis B surface antigen (HBsAg) and of other HBV markers were 0.8 and 6.8 respectively. Compared with a similar previous study conducted in Naples in 1980, the results show a significant reduction in the prevalence of anti-HAV in each of the two age-groups (P less than 0.01), in the prevalence of any HBV marker in the 11 to 12-year-old group, as well as in the total population (P less than 0.05). The findings of the present study indicate that today, children in Naples are less exposed to the hepatitis A virus than in the past, most likely because of improvements in both the socioeconomic conditions and in health education during recent years. These same reasons, as well as decreased family size and a lower prevalence of HBeAg among HBsAg carriers could explain the decline, although to a lesser degree, of exposure to HBV infection.

Child↗
PubMed1988

The new basement membrane antigen recognized by the monoclonal antibody GB3 is a large size glycoprotein: modulation of its expression by retinoic acid.

Further biochemical investigations on the hemidesmosome-associated epidermal basement membrane component recognized by the monoclonal antibody GB3 are presented in this study. We previously found that the expression of this constituent is impaired in a severe genodermatosis termed lethal junctional epidermolysis bullosa. We demonstrate now that this factor is a very large glycoprotein (apparent molecular weight, 600 kDa) made up of polypeptides in the range of 93.5 to 150 kDa, and containing N-linked oligosaccharide chains. Both endo-beta-N-acetylglucosaminidases and neuraminidase hydrolysis, as well as concanavalin A binding experiments were performed on the GB3 radioimmunoprecipitated polypeptides from cultured human keratinocytes. They showed that the antigen subunits probably bear both 'high-mannose' and 'complex' type glycosidic chains. The chronic exposure of cultured human keratinocytes to retinoic acid (10(-8) to 10(-6) M) resulted in no apparent changes in the overall bulk of these glycosidic chains, but a dose-dependent increase of synthesis and secretion of the antigen was observed. A relative induction factor of 4 was obtained in cultures treated with 10(-6) M retinoic acid. This induction was also observed morphologically by indirect immunofluorescence at the basement membrane zone from cultured human keratinocytes grown on dead de-epidermized dermis. These results further emphasize the influence of glycoproteins in cell-cell and cell-substratum attachment. Furthermore, the ability to modulate this antigen may be relevant for the understanding of the molecular defect involved in lethal junctional epidermolysis bullosa.

Antibodies, Monoclonal↗
PubMed1988

Normal Merkel cells express a synaptophysin-like immunoreactivity.

Synaptophysin (SY), a specific component of the membrane of presynaptic vesicles, has been reported as a novel marker for neurons, certain neuroendocrine cells and their neoplasms including neuroendocrine carcinomas of the skin. The origin of the Merkel cells (MC) being far from clear, this study was performed to establish if normal MC express SY. It is demonstrated by immunofluorescence and immunoelectron microscopy using a monoclonal antibody SY38 to this glycoprotein that normal MC in man, rabbit and pigs express an SY-like reactivity. Although immunoblotting identification of the immunoreactive material gave negative results, it is likely that normal MC contain SY. By immunoelectron microscopy, the staining was located at the surface of cytoplasmic vesicles. In view of the possible involvement of SY in the Ca2+-dependent neurotransmitter release, the observation of an SY-like immunoreactivity in MC supports the view that they are epithelial neuroendocrine cells and that they may possess a neurosecretory function.

Animals↗
PubMed1988

The biological evolution of the Leeds-Keio ligament in the human knee. A histological and ultrastructural study.

The authors report their experience in the reconstruction of the anterior cruciate ligament using the Leeds-Keio ligament in 12 patients, 7 by open arthrotomy and 5 by an arthroscopic technique. The biological evolution of the new ligament was studied macroscopically and histologically in the first 6 cases treated by open arthrotomy. Arthroscopic monitoring and biopsy was carried out 4 to 10 months after operation. In 5 cases the new ligament appeared to be intact and histologically vital, with proliferation of new tissue along the new ligament. There were broken filaments of dacron hanging from the intercondylar cavity in only one case. The first macroscopic, histological and ultrastructural results show that despite a few limitations the Leeds-Keio ligament has the features required for replacement of the anterior cruciate ligament, although it will be necessary to wait 4 or 5 years before fully evaluating the durability and function of the ligament and the best operative method.

Adolescent↗
PubMed1988

Effect of chronic sun exposure on human Langerhans cell densities.

This study evaluated the Langerhans cell density in chronically sun-exposed skin (hand) and non-exposed skin (buttock) in subjects that were divided into 4 age groups (20-40; 41-60; 61-80; greater than 81 years). Two markers (OKT-6 and anti-HLA-DR) were used to identify the Langerhans cells (LC), and their count was performed either on epidermal sheets (52 individuals) or skin sections (43 individuals). Three major findings result from this study: 1) there are more LC in the non-exposed skin than in the chronically sun-exposed area; 2) there were no age-related changes in LC counts, and 3) LC co-express the T6 and HLA-DR antigens.

Adolescent↗
PubMed1987

Monoclonal antibody GB3, a new probe for the study of human basement membranes and hemidesmosomes.

A monoclonal antibody, GB3, has been raised against human amnion. Not only does GB3 bind to amniotic basement membrane, but it also recognizes an antigenic structure expressed by epidermal as well as by some other human basement membranes. This antigen is synthesized (and excreted) by cultured normal human epidermal keratinocytes. It is expressed to a lesser extent by the A431 epidermoid carcinoma cell line, but is not expressed by the SV40 virus-transformed SVK14 keratinocyte cell line. In ultrastructural studies, this antigen was located in the epidermal basement membrane, both in the lamina densa and in the lamina lucida, associated with hemidesmosomes. It was identified as a protein by in vitro proteolytic cleavage studies. The radio-immunoprecipitates from cultured human keratinocytes, analysed by SDS-PAGE, showed that GB3 recognized five polypeptides of 93.5, 125, 130, 146 and 150 kD under reducing conditions. They were probably linked by disulfide bonds. The tissue distribution of the antigen and the molecular weights (MWs) of its constitutive polypeptides suggest that it is different from other known components of basement membranes. It may provide a biochemical marker for hemidesmosomes. Furthermore, GB3 represents an interesting and original clinical probe, since the antigenic structure recognized by GB3 is lacking in Junctional Epidermolysis Bullosa, a lethal genodermatosis in which a dermo-epidermal splitting occurs at the level of lamina lucida.

Amnion↗
PubMed1987

Herpes gestationis factor reacts with the amniotic epithelial basement membrane.

Sera from five patients with clinically and immunopathologically proven herpes gestationis were studied by complement fixing immunofluorescence and complement fixing immuno-electron microscopy using specimens of skin, amniochorion and placenta. The results demonstrated that the complement fixation antibody (herpes gestationis factor) could bind to the basement membrane zone of skin, amnion and chorion laeve but not to that of the placental syncytiotrophoblast. These data suggest that the herpes gestationis factor may be induced by the basement membrane zone antigens of extra-villous cytotrophoblasts.

Amnion↗
PubMed1987

The majority of epidermal Merkel cells are non-proliferative: a quantitative immunofluorescence analysis.

Although epidermal Merkel cells (MC) are able to form synapses and synthetize neuromediators, they can be considered as being of epithelial nature because of the presence of cytokeratins in their cytoskeleton and desmosomes on their membranes. Since epidermis is an epithelium undergoing permanent renewal, it was important to determine whether MC were able to renew, as neighbouring keratinocytes do. This was investigated by studying whether S phase nuclei could be found in cells bearing a specific MC marker. The technique consisted of injecting rabbits with bromodeoxyuridine (BrdUrd) and performing double immunofluorescence on skin sections with the antikeratin number 8 monoclonal antibody (MAb) TROMA-I and anti-BrdUrd MAb. The results show that, in contrast to the neighbouring epidermal cells, the great majority of MC were found to be devoid of BrdUrd labelling, indicating that most of these cells are unable to divide, or divide very rarely.

Animals↗
PubMed1977

Metallic foreign bodies in the stomach.

We present a case of a patient who ingested 648 metallic objects that formed an intertwining mass within the stomach, requiring operative removal. Of interest was the absence of symptoms and complications after 11 years of continual ingestion. To our knowledge, this is the second heaviest accumulation of metallic foreign objects removed from the stomach of a living patient.

Adult↗
PubMedDate not supplied

Colonoscopic removal of a polypoid arteriovenous malformation.

A 53-year-old male presenting with a 3-month history of intermittent mild rectal bleeding was found, on double contrast barium enema, to have a large polyp on a long stalk in the sigmoid colon. Large bowel endoscopy confirmed the presence of a 2 cm pedunculated polyp which was removed using a diathermic snare, with slight bleeding following the procedure that did not require endoscopic haemostasis. Only after histologic examination was the polyp shown to be a colonic arteriovenous malformation. Endoscopically, arteriovenous malformations generally appear as flat or elevated bright red lesions. A pedunculated polypoid appearance is extremely uncommon. In this case, no gastrointestinal bleeding or polypoid recurrence was observed during the 12 months of clinical and endoscopic follow-up.

Arteriovenous Malformations↗
PubMedDate not supplied

Morphological changes induced by prolonged darkness in the retinal pigment epithelium of the turtle (Pseudemys scripta elegans).

The retinal pigment epithelium of Vertebrates was shown to be sensitive to cyclic oscillations of light and darkness. The morphological changes induced by prolonged darkness on the retinal epithelial cells of the freshwater turtle were studied, with particular regard to their localization and to their reversibility if animals are recovered under cyclic light. The eyes were processed for light and electron microscopy and a morphological and morphometric analysis was performed on the specimens. After 7 days of prolonged darkness, the vitreal extremity of some epithelial cells was partially detached; on the basal zone the infoldings were missing and vesicles and tubules, often arranged in rows, were observed. After 30 days of prolonged darkness, partial or complete double layers of epithelial cells were present: the superficial layer was connected, by means of the apical fringes, to the photoreceptors, whilst the deepest layer showed vesicles and tubules on its basal zone. After 7 days of recovery to L:D = 12:12, no cyclic activity was demonstrated and only occasional double layers of cells were present; on the basal surface isolated basal infoldings were present where two adjacent cells were joined together. It could be concluded that the detachment of the apical part of some cells, rapidly covered by the lateral sliding of the adjacent cells, and the substitution of the basal infoldings with vesicles and tubules could represent the morphological response of the retinal epithelium to the functional changes induced by prolonged darkness.

Animals↗
PubMedDate not supplied

[Progression of chronic renal failure in remnant rats: role of arginase inhibition].

BACKGROUND: Oral administration of arginine to remnant (REM) rats (5/6 nx) slows the progression of chronic renal failure through a nitric-oxide(NO)-dependent mechanism. We have recently shown that inhibition of arginase, the main metabolic pathway of arginine, was able to induce similar results on renal dynamics (GIN: 2001, 18:285-290). Aim of the present study was to test whether these changes were mediated by increased availability of arginine-derived NO. Methods. Three Groups of REM rats were studied for 8 weeks after surgery: 1) untreated REM (Group REM); 2) REM rats treated with arginine (1%) in tap water (Group ARG); 3) REM rats administered a Mn++-free diet, to induce partial inhibition of arginase (Group MNF). Normal unmanipulated rats were used as controls (Group NOR). RESULTS: Liver arginase activity was significantly depressed only in MNF-rats (-35% vs. REM, p < 0.01). Blood pressure was significantly lower in Group MNF vs. ARG and REM after 6 weeks (p < 0.05). Proteinuria was significantly decreased in Group ARG (-42%, p < 0.05 vs. REM) and even more in Group MNF (-57%, p < 0.01). ARG plasma levels, decreased in REM rats (-41% vs. Group CON), were normalized in Group ARG (p < 0.01 vs. Group REM); arginase inhibition was able to increase such levels in Group MNF (+38% vs. REM) and this resulted in a proportional rise in urinary nitrite excretion (+33% vs. REM), grossly depressed in REM rats. Renal arginase activity was lower in all the Groups of remnant rats vs. Group NOR, but intrarenal concentrations of ARG were significantly lower only in rats of Group MNF (p < 0.05 vs. all the other Groups). Histological examination showed that MNF-rats had a glomerular sclerosis index lower than in the other Groups (p < 0.05 vs. Group REM and ARG). CONCLUSIONS: In conclusion, inhibition of arginase in remnant rats slows the progression of CRF and preserves renal histology through a direct and/or indirect NO-dependent mechanism.

Animals↗
PubMedDate not supplied

[Effects of atorvastatin on ischemic acute renal failure in aging rats].

BACKGROUND: Aging (O) rats have a greater susceptibility to renal ischemia than young (Y) rats due to an endothelial dysfunction partially reversed by exogenous administration of L-Arginine. Since statins are able to increase nitric oxide (NO) production, aim of the study was to evaluate whether pre-treatment with atorvastatin (ATO, 10 mg/kg/day for 12 days), had positive effects on ischemic acute renal failure (ARF) of aging rats. METHODS: Renal clearance studies (inulin) were performed 24 hours after ischemia in 6 Groups (n=6 in each Group) of both Y- and O-rats: control rats (CON), untreated rats with ARF (Groups IRA), and rats with ARF but pretreated with ATO (Groups ATO+IRA). RESULTS: Renal ischemia determined a sharper decrease in GFR of Group O-IRA than Y-IRA (-80% and -63% vs respective CON, both p<0.001). In both Groups the fall in GFR was secondary to renal vasoconstriction and the consequent reduction in renal plasma flow. Pre-treatment with ATO did not modify GFR in Group Y-ATO+IRA, but was able to determine a marked rise in GFR of rats of O-ATO+IRA Group (+100% vs O-IRA), through a reduction in renal vascular resistances. Induction of ARF greatly enhanced nitrate excretion in Group Y-IRA, but slightly affected Group O-ARF. Administration of ATO did not modify nitrite excretion in Y rats, whereas it was able to increase nitrate excretion in O-ATO+ARF rats (+111% vs O-IRA). CONCLUSIONS: Pre-treatment with ATO is able to improve the renal response to ischemia in aging rats, through a mechanism which likely is NO-dependent.

Acute Kidney Injury↗
PubMedDate not supplied

[Anderson-Fabry's disease: diagnostic problems, therapeutic relevance, and clinical experience in the treatment of the disease with enzyme replacement therapy in nephropathic patients].

Aim of this study was to confirm the initial results of a clinical trial on the treatment of Fabry's disease carried out in 13 Italian Nephrology Units. Fabry's disease is a rare, X-linked inherited disease, characterized by a-galactosidase (a-GAL) deficiency, a lysosomial enzymatic activity that results in the accumulation of neutral glycosphingolipids in the endothelial cells of the whole body, and causes painful crises, acroparesthesiae, angiokeratomas, corneal and lens dystrophy, and progressive damage to kidneys, heart and central nervous system, as well as potentially leading to death. The present availability of the recombinant form of a-GAL allows us to prevent or stop the long-term complications of this disease. A clinical trial, generously supported by Genzyme, was started on February 2001. In this trial 20 patients affected by Fabry's disease were periodically treated with agalsidase-beta, the commercial form of the enzyme. The initial results of the trial have indicated that the drug is capable of reducing both the number and intensity of painful crises, improving the patient's sensation of well-being, thus suggesting that this therapeutic approach might theoretically increase life expectancy in these patients.

Chromosomes, Human, X↗