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Biomedical subjects

L Bianchi

Publications and source records attributed to L Bianchi.

At least 19 recordsLinked to original sources
PubMed1995

[Does serum HCV-RNA-positive hepatitis C differ from serum HCV-RNA-negative hepatitis C?].

Viral RNA is detectable in the serum of the majority but not all patients with chronic hepatitis C. Whether the viremic form differs from the non-viremic form of the disease is unknown. We therefore compared histology (modified Knodell score) and liver function (conventional liver function tests, galactose elimination capacity and aminopyrin breath test) of viremic (n = 45) and non-viremic (n = 37) patients with chronic hepatitis C. Neither the total histologic score, nor any of the individual histologic parameters assessed differed significantly in serum HCV RNA positive and negative patients. Compared to non-viremic subjects, patients with detectable HCV RNA in serum had slightly higher transaminases (p = ns), lower serum albumin (p < 0.05) and decreased galactose elimination capacity (p < 0.05). This trend towards more severe functional hepatic impairment in serum HCV RNA positive patients persisted when cirrhotics and non-cirrhotics were analyzed separately; it fell just short of reaching statistical significance, however, most probably due to the small number of subjects per patient group. The median age of serum HCV RNA positive cirrhotics was 17 years, and that of serum HCV RNA negative cirrhotics 22 years higher than that of the respective non-cirrhotics. Biochemical (transaminases) and histological (intralobular and piece-meal necrosis) markers of disease activity, as well as metabolic functional reserve (aminopyrin breath test, galactose elimination capacity) and histologic severity of fibrosis correlated only loosely (Rs = 0.24-0.56), albeit significantly (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

An inward rectifier K+ current modulates in neuroblastoma cells the tyrosine phosphorylation of the pp125FAK and associated proteins: role in neuritogenesis.

The relationships between the integrin-mediated activation of inward rectifyier K+ channels (KIR), the phosphorylation of pp125FAK and the rescue of neuritogenesis were studied in 41A3 mouse neuroblastoma cells. Neuritogenesis, elicited by adhesion to FN-enriched substrata, was reversibly impaired by pretreating these cells with the tyrosine kinase inhibitor Herbimycin A. This impairment mimicked that operated by Cs+ ions, which selectively inhibited the integrin-mediated activation of KIR channels. Various phosphotyrosine containing cellular proteins underwent a marked increase upon cell adhesion to FN-coated dishes. This increase was significantly reduced by Cs+ addition. Immunoprecipitation of pp125FAK revealed that the phosphorylation of this kinase and several associated proteins was significantly and reversibly inhibited by Cs+, indicating that integrin-mediated activation of KIR channels is a limiting step upstream to the phosphorylation of pp125FAK in the commitment to neuritogenesis.

Animals↗
PubMed1995

Photoinduction of micronuclei by 4,4',6-trimethylangelicin and 8-methoxypsoralen in different experimental models.

The frequencies of micronuclei induced by treatment with 4,4',6-trimethylangelicin (TMA) and 8-methoxypsoralen (8-MOP) have been compared in the following experimental models: (1) peripheral normochromatic erythrocytes (NCE) during 10 days after single p.o. administration of TMA or 8-MOP in male and female mice; (2) peripheral NCE during photocarcinogenesis by TMA or 8-MOP topically administered to female mice; (3) primary cultures of human skin fibroblasts treated with TMA or 8-MOP. The frequency of micronuclei in peripheral NCE of mice (both sexes) was significantly enhanced after p.o. administration of TMA or 8-MOP. This latter was more active than TMA in inducing chromosomal damage. No increased frequencies of micronuclei in peripheral NCE were detected in mice subjected to TMA or 8-MOP photocarcinogenic treatment, even when malignancies developed. In human fibroblast cultures, at equimolar concentrations, the induction of lethal effects by TMA in the presence of 365-nm radiation was higher than that exerted by 8-MOP. At equal survival, however, TMA showed practically the same activity as 8-MOP in the induction of micronuclei. Our findings provide evidence of genotoxicity by TMA administered p.o. without irradiation and give further information about photogenotoxicity of these substances.

Animals↗
PubMed1995

Differential regulation by N-methyl-D-aspartate and non-N-methyl-D-aspartate receptors of acetylcholine release from the rat striatum in vivo.

The modulation of striatal cholinergic neurons by glutamatergic inputs was studied by monitoring the output of acetylcholine collected via a transversal microdialysis probe implanted into the striatum of freely moving rats. A transversal microdialysis membrane was inserted in the striatum and acetylcholine or GABA levels in the dialysate were measured. Acetylcholine levels in the dialysate were quantified by a high-performance liquid chromatography method with an electrochemical detector, while GABA levels were measured by a high-performance liquid chromatography method with a fluorescence detector. The dialysis membrane was perfused with Ringer solution containing 7 microM physostigmine sulphate and drugs, dissolved in the perfusion solution, were administered locally via the dialysis membrane. Local administration of the N-methyl-D-aspartate antagonist 3-[(RS)-2-carboxypiperazin-4-yl]-propyl-1-phosphonic acid (25-100 microM) brought about a decrease in striatal acetylcholine output which was dose-dependent, reversible and partially antagonized by 100 microM N-methyl-D-aspartate. On the other hand, local administration of the non-N-methyl-D-aspartate antagonist 2,3-dihydroxy-6-nitro-7-sulfamoil-benzo(F)quinoxaline was followed by an increase in acetylcholine output which reached a maximum of about +55% at 12.8 microM 2,3-dihydroxy-6-nitro-7-sulfamoil-benzo(F)quinoxaline and was readily reversed when the drug was withdrawn from the perfusion solution. Local administration of the non-N-methyl-D-aspartate receptor agonist (S)-alfa-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (50 and 200 microM) decreased acetylcholine output and this effect was reversed by simultaneous perfusion with the GABA antagonist bicuculline (50 microM).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1995

Pachydermoperiostosis: study of epidermal growth factor and steroid receptors.

Pachydermoperiostosis is a rare osteo-cutaneous disease characterized by hypertrophy of bones and surrounding soft tissues. The cutaneous manifestations include coarsening of facial features, cutis verticis gyrata, digital clubbing, hyperhidrosis and seborrhoea. The pathogenetic mechanism of the disease is still debated, and proposed aetiological factors include genetic influences, anomalies in fibroblast activity, or alteration in peripheral blood flow. We studied a patient with the incomplete form of pachydermoperiostosis, assessing epidermal growth factor receptor (EGF-R) and sex hormone steroid receptors (SR) in the affected skin, and also evaluating the urinary excretion of EGF. The results showed high levels of nuclear steroid receptors, increased cytosolic oestrogen receptors, and no detectable progesterone and androgen cytosolic receptors. EGF-R was also undetectable, and the urinary excretion of EGF was elevated. These findings suggest that the increased tissue sensitivity to circulating sex-steroids could induce enhanced tissue EGF/transforming growth factor alpha (TGF-alpha) production and utilization. The SR-EGF-R system could therefore be involved in determining hypertrophy of the affected tissues.

Adult↗
PubMed1995

Intramuscular myxoma of the face: an unusual localization. A clinicopathological study.

BACKGROUND: Intramuscular myxoma is a rare benign mesenchymal lesion. Only very rare cases of cutaneous localization of this tumor have been described, in particular related to the somatic soft tissues of the face. This unusual localization may clinically mimic nodular or cystic facial lesions having different origins. OBJECTIVE: The aim of our work was to well characterize the phenotype of the spindle cells characteristic of intramuscular mixoma. METHODS: Tissue samples were processed for morphological and ultrastructural studies. Moreover, immunohistochemical stainings were performed to characterize the expression of different nonmuscular and muscular cytoskeletal proteins. RESULTS: The tumor was composed of sparse spindle cells embedded in a prominent mucoid matrix. Besides the predominance of a fibroblast-like appearance, some neoplastic cells displayed immunohistochemical and ultrastructural features resembling either myofibroblasts or primitive mesenchymal cells, with a modulation of cell actin expression. CONCLUSION: The presence of multiple phenotypes of nonmuscular, mesenchymal pathway of differentiation can be considered a peculiar feature of intramuscular myxoma.

Facial Neoplasms↗
PubMed1995

Twenty-four-hour noninvasive blood pressure monitoring and pain perception.

Although a hypertension-related hypalgesia has been described, the relation between pain perception and the 24-hour blood pressure trend is still unknown. The ambulatory blood pressure monitoring parameters and dental pain sensitivity were correlated in 67 male subjects. The pulpar test (graded increase of test current of 0 to 0.03 mA) was performed on three healthy teeth, and mean dental pain threshold (occurrence of pulp sensation) and pain tolerance (time when the subjects asked for the test to be stopped) were evaluated. Three groups of subjects with normal (n = 34), intermediate (n = 13), and high (n = 20) blood pressure values were identified according to ambulatory monitoring results. Pain threshold differed among the three groups (P < .02), being higher in the group with highest blood pressure. The groups of hypertensive subjects showed higher pain tolerance than the normotensive group (P < .02). Pain threshold was correlated with 24-hour, diurnal, and nocturnal blood pressure values. Pain tolerance was also related to 24-hour blood pressure and to diurnal and nocturnal diastolic and mean arterial pressure values. Systolic and diastolic blood pressure loads were significantly associated with pain threshold, and diastolic load was also associated with tolerance. The blood pressure variability (SD) did not relate to pain perception. The 24-hour arterial pressure was more closely associated with pain perception than the blood pressure values obtained before the pulpar test. A close correlation between pain perception and 24-hour ambulatory blood pressure was demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Guidelines for the management of community-acquired pneumonia in adults. Italian Society of Pneumology. Italian Society of Respiratory Medicine. Italian Society of Chemotherapy.

In general practice Community-acquired Pneumonia (CAP) is most often treated on an empyrical basis. Therefore, it is of the utmost importance to know the epidemiology of respiratory pathogens in order to give some guidelines for the empirical management of CAP. At present in cases of mild and moderate severity, ampicillin or amoxycillin, preferably in association with sulbactam and clavulanic acid respectively, and macrolides are the antibiotics of first choice. The latter can be an alternative to beta-lactams when Legionella, Mycoplasma and Chlamydia are the suspected etiologic agents or when patients are allergic to penicillins. They can also be used in combination with beta-lactams when etiological diagnosis is extremely uncertain. The course and severity of the disease, a chest radiograph, the results of microbiological and other laboratory examinations will determine the choice of further antibiotic treatment and other therapeutic measures, if necessary.

Adult↗
PubMed1995

Pregnancies in postmenopausal women over 50 years old in an oocyte donation program.

OBJECTIVE: To determine the potential of the aging uterus in terms of pregnancy, implantation, and abortion rates, and obstetric complications in postmenopausal women age 50 and over, receiving oocyte donation. DESIGN: Retrospective data analysis. SETTING: A tertiary infertility center. PATIENTS: Thirty-four postmenopausal women (50 to 62 years of age) undergoing a total of 61 cycles of oocyte donation. INTERVENTIONS: Hormone replacement therapy (HRT) was given using increasing doses of 17 beta-E2 (2, 4, and 6 mg) and 100 mg of P in oil. MAIN OUTCOME MEASURES: Pregnancy, abortion, and implantation rates, and pregnancy outcome. RESULTS: There were 34 patients treated through 61 cycles. Fifty-five transfer cycles were performed. A total of 18 clinical pregnancies were achieved with a pregnancy rate per transfer of 32.7% and per patient of 52.9%. There was one abortion, resulting in an abortion rate of 5.5%. Twenty-one of the 116 transferred embryos implanted, resulting in an implantation rate of 18%. No statistically different rates were found in oocytes donors. CONCLUSION: Women over the age of 50 and up to 62 can become pregnant using donated oocytes. The aging uterus after HRT allows implantation as well as in young women, and it is able to carry pregnancy to term apparently without any problems.

Abortion, Spontaneous↗
PubMed1994

[Giant cell hepatitis in adults].

Differential diagnosis of progressive cholestatic liver disease includes postinfantile giant-cell hepatitis, particularly in cases with negative serology for hepatitis viruses and in the absence of an intake of potentially hepatotoxic drugs. Diagnosis is made by the histologic demonstration of syncytial giant cells in liver. To the knowledge of the authors, some 70 cases have been published so far; however, the true prevalence of the disease appears to be much higher than commonly assumed. Hepatocellular giant cells, the only diagnostic marker, may be expressed in low copy numbers, and many cases thus easily escape recognition. Some 50% of the published cases are positive for autoantibodies in serum or combined with other features of autoimmunity. A correct diagnosis is important in view of the unfavorable prognosis with a rapidly progressive course in about half the cases. Fulminant liver failure and late cirrhotic stages are candidates for liver transplantation. After transplantation no recurrence of giant-cell hepatitis has been observed. Cases positive for autoantibodies have been successfully treated with corticosteroids; cholestatic forms appear to respond to ursodeoxycholic acid. Etiology of the disease is not settled. Some authors claim aberrant immunoreactivity from various causes to be responsible for the disease, others have presented evidence in favor of a paramyxovirus infection. In any case of cholestasis of unknown origin, serology for paramyxoviruses and a liver biopsy are recommended.

Autoantibodies↗
PubMed1994

The effect of kainic acid on the release of GABA in rat neostriatum and substantia nigra.

In order to test the hypotheses that stimulation of non-N-methyl-D-aspartate (NMDA) receptors in the neostriatum causes the release of gamma-aminobutyric acid (GABA) from nigrostriatal neurones, dual microdialysis was carried out in the neostriatum and substantia nigra of freely moving rats. Application of kainic acid to the neostriatum caused a dose-dependent release of GABA both locally and, at the same time, from the ipsilateral substantia nigra. These effects were blocked by the non-NMDA receptor antagonist 6,7-dinitroquinoxaline-2,3-dione (DNQX). Direct application of kainic acid to the substantia nigra caused a DNQX-sensitive local release of GABA. It is concluded that excitatory amino acid receptor stimulation of the neostriatum releases GABA from striatonigral neurones and that stimulation of the substantia nigra causes the release from striatonigral terminals and/or the collaterals of nigrofugal neurones.

Animals↗
PubMed1994

Hepatitis C virus infection is a risk factor for liver failure from veno-occlusive disease after bone marrow transplantation.

The contribution of hepatitis C virus (HCV) infection to liver disease after bone marrow transplantation (BMT) was retrospectively evaluated in 61 patients treated with BMT. HCV genome, as well as antibodies to HCV, was analyzed in sera collected before and serially after BMT. Six patients had been infected with HCV before BMT and three patients acquired the infection during or shortly after BMT. All patients infected before BMT died within 10 weeks after transplantation. Five of these six patients (83%) died of veno-occlusive disease (VOD), compared with nine of 52 patients (17%) not infected with HCV (P < .005). Risk factors for VOD other than HCV were not more prevalent in these patients compared with uninfected patients. Parallel to the development of VOD, replication of HCV increased, as demonstrated by rising concentrations of viral RNA in serum. HCV infection acquired during or after BMT caused only mild acute hepatitis C, which progressed to chronic hepatitis C in one patient surviving 10 years after BMT. These data suggest that patients with liver disease caused by HCV infection are at high risk of developing lethal VOD after BMT.

Adolescent↗
PubMed1994

Muscarinic regulation of Ca2+ currents in rat sensory neurons: channel and receptor types, dose-response relationships and cross-talk pathways.

We studied, in rat sensory neurons, the modulation of high voltage-activated Ca2+ currents (ICa) mediated by the pertussis toxin-sensitive activation of muscarinic receptors, which were found to be of subtypes M2 or M4. Muscarine reversibly blocked somatic Ca2+ spikes but strong predepolarizations only partially relieved the inhibited Ca2+ current. On the other hand, the putative coupling messenger could not rapidly diffuse towards channels whose activity was recorded from a macro-patch. The perforated patch technique virtually prevented the response rundown present during whole-cell experiments. Both omega-conotoxin GVIA (omega-CgTx)-sensitive channels and omega-CgTx- and dihydropyridine-resistant channels are coupled to the muscarinic receptor, but not the L-channel. When measured in the same neuron, dose-response relationships for the first and subsequent agonist applications differed; maximal inhibition, the reciprocal of half-maximal concentration and the Hill coefficient were always highest in the first trial. Muscarine and oxotremorine exhibited monotone dose-response curves, but oxotremorine-M showed non-linear relationships which became monotonic when cells were intracellularly perfused with inhibitors of protein kinase A (PKA) and C (PKC), suggesting that either PKA or receptor-induced PKC could phosphorylate and thus inactive G-proteins or other unknown proteins involved in inhibitory muscarinic actions on ICa. In summary, these data provide a preliminary pharmacological characterization of the muscarinic inhibition of the Ca2+ channels in sensory neurons, with implications about agonist specificity and the interplay between signalling pathways.

Action Potentials↗
PubMed1994

Proliferating cell nuclear antigen bound to DNA synthesis sites: phosphorylation and association with cyclin D1 and cyclin A.

Evidence is presented that association of proliferating cell nuclear antigen (PCNA) with nuclear chromatin in human fibroblasts is related to the phosphorylation status of the protein. Using a hypotonic lysis procedure to extract the soluble form of PCNA, it has been shown that the remaining nuclear-bound form, predominantly in S-phase cells, is highly phosphorylated. Cells in early G1, or in G2 + M phases, contain basal levels of the bound form of the protein that is only weakly phosphorylated. Using fractionated immunoprecipitation techniques, PCNA was found to be associated with cyclin A in both soluble and insoluble fractions. In contrast, association of PCNA with cyclin D1 was found in the soluble fraction, while no detectable levels were present in the insoluble fraction. Immunofluorescence labeling and flow cytometric analysis of the cell cycle distribution of cyclin D1 and cyclin A showed that, like PCNA, maximal levels of both proteins were bound to nuclear structures at the G1/S phase boundary. These results suggest that binding of PCNA to DNA synthesis sites occurs after phosphorylation. Association with cyclin D1 and cyclin A might occur in a macromolecular complex assembled at the G1/S phase boundary to drive activation of DNA replication factors.

Binding Sites↗