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Biomedical subjects

C Bianchi

Publications and source records attributed to C Bianchi.

At least 163 records · Page 9Linked to original sources
PubMed1995

[Bacterial endocarditis in pregnancy. Report of a clinical case diagnosed postpartum].

Bacterial endocarditis in pregnancy shows a low incidence; it is often associated with a prior history of rheumatic or congenital heart disease. In the large part of reports the illness tends to run a subacute course and to recognize a major frequency in the third trimester of pregnancy. We presented the case of a 29 year-old woman with mitral and aortic bacterial endocarditis. Transthoracic echocardiography performed one week after spontaneous delivery suggested valve vegetations. Antibiotic therapy turned out to be partially successful, in fact cerebral embolizations subsequently occurred. Conservative surgery appeared to be favourable and the patient shows a satisfactory present clinical state.

Adult↗
PubMed1994

Adenosine A1 receptors in the rat brain in the kindling model of epilepsy.

Adenosine and adenosine analogues have potent anticonvulsant effects on various seizure models, including kindling, an animal model of temporal lobe epilepsy. It is now reported that binding of a specific ligand (cyclohexyladenosine) to adenosine A1 receptors is not changed in the cerebral cortex of kindled rats. However, the affinity of cyclohexyladenosine to adenosine receptors is significantly increased in the hippocampus. In addition, cyclohexyladenosine is slightly more potent to inhibit [3H]D-aspartate outflow from hippocampal synaptosomes taken from kindled than from control rats. Taken together, these data suggest that an increased affinity of adenosine to A1 receptors may play a role in the anticonvulsant effect of adenosine A1 analogues in the kindling model.

Adenosine↗
PubMed1994

Antibodies for the immunochemistry of the human beta 3-adrenergic receptor.

Based on the amino acid sequence deduced from the recently cloned human beta 3-adrenergic receptor (hu beta 3AR) gene, polyclonal antibodies were prepared against synthetic peptides, corresponding to regions of hu beta 3AR presumed to be exposed at the outer or the inner side of the membrane on the basis of the putative three-dimensional structure of the previously characterized beta 1 and beta 2 adrenergic receptors. Affinity-purified antibodies directed against N-terminal, extracellular or intracellular loops and C-terminal peptides reacted specifically with the hu beta 3AR and not with either the human beta 1 or beta 2 adrenergic receptor. Using these antibodies, it was demonstrated that the receptor is present at the surface of Chinese Hamster Ovary (CHO) cells transfected with the hu beta 3AR gene; in addition, the presence of the receptor protein was established in a human tissue (gall bladder). Immuno-affinity chromatography of solubilized CHO hu beta 3AR-containing cell membranes allowed the isolation of hu beta 3AR protein with an overall yield of 30%. The degree of purity of the receptor was more than 80%, as assessed by N-terminal sequencing of the protein eluted from the column. Sequence analysis demonstrated the absence of a methionine residue at the N-terminal position, and suggested that the side chain of the asparagine residue at position 7 is glycosylated.

Amino Acid Sequence↗
PubMed1994

6-hydroxy-dopamine treatment counteracts the reduction of cortical GABA release produced by the vigilance promoting drug modafinil in the awake freely moving guinea-pig.

The effects of acute and repeated treatments with modafinil (30 mg/kg, s.c.) alone or after i.c.v. 6-hydroxy-dopamine injection were studied on cortical GABA release as well as on cortical/striatal catecholamine levels in awake freely moving guinea pig. The results show that repeated daily modafinil treatment produces a similar but short-lasting reduction of GABA outflow compared with acute administration. A significant reduction of cortical basal GABA outflow was observed in animals treated with 6-hydroxy-dopamine, which was maintained also after modafinil treatments. Furthermore, after the 6-hydroxy-dopamine treatment, modafinil fails to inhibit cortical GABA release. The depleting action of the toxin, 17% reduction of neostriatal dopamine levels and 35% of noradrenaline levels in the parietal cortex, was not influenced by repeated modafinil treatment. The catecholaminergic telencephalic networks therefore seem essential for the elicitation of the inhibitory effects of modafinil on GABA release.

Animals↗
PubMed1994

Selective opioid dipeptides.

The surprising change of selectivity induced by the change of chirality in peptides containing the tetrahydro-3-isoquinoline carboxylic acid (Tic) in second position, interpreted as a conformational preference induced on the Tyr-Xaa-Phe domain, can instead be attributed to the Tyr-Tic message domain. The relative spatial disposition of the aromatic ring of delta-selective non peptidic opiates is compatible with a message domain, in opioid peptides, of only two residues. This hypothesis was tested through the synthesis of Tyr-L-Tic-NH2, Tyr-D-Tic-NH2, Tyr-L-Tic-Ala-NH2, Tyr-L-Tic-Ala-OH and Tyr-D-Tic-Ala-NH2. Peptides containing Tyr-L-Tic- behave as very selective delta antagonists and those containing Tyr-DTic- as non selective agonists. This is the first case of opioid peptides containing a two-residue message domain and of opioid dipeptides with substantial opioid activity.

Amino Acid Sequence↗
PubMed1994

Monoamines modulate the electrically-evoked efflux of 3H-choline from slices of guinea pig nucleus basalis magnocellularis.

The influence exerted by monoamines on acetylcholine release was studied in electrically stimulated slices of guinea pig nucleus basalis magnocellularis (nbM) prelabelled with 3H-choline (3H-Ch). Noradrenaline, 30 microM, and clonidine, 1 microM, reduced the evoked 3H-Ch efflux by about 50%, but phenylephrine, 100 microM, did not; idazoxan, 0.1 microM, but not prazosin, 1 microM, antagonized these effects, pointing to the involvement of alpha 2 receptors. Apomorphine, 1 or 30 microM, reduced 3H-Ch efflux from nbM slices as well. The effect was shared by quinpirole, 1 or 10 microM, but not by 2,3,4,5-tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine (SKF 38393), 10 microM, and was antagonized by sulpiride, 1 microM, but not by R-(+)-8-chloro-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1H-3-benzazepin++ +-7-ol (SCH 23390), 1 microM, suggesting the involvement of the D2 receptor subtype. 5-hydroxytryptamine (5-HT) 0.3-30 microM, and alpha-methyl-5-HT, 10 microM, significantly increased 3H-Ch efflux from nbM slices; the 5-HT2 antagonist ritanserin, 1 microM, prevented this response. 2-methyl-5-HT, 1-30 microM, inhibited the evoked 3H-Ch efflux and its effect was prevented by the 5-HT3 antagonist 1 alpha H,3 alpha,5 alpha H-tropan-3-yl-3,5-dichlorobenzoate (MDL 72222), 1 microM. These findings indicate that i) catecholamines inhibit nbM neurons through alpha 2 and D2 receptors and that ii) a complex serotonergic modulation of cholinergic function exists in the nbM, involving the activation of various receptor subtypes, which can mediate opposite responses.

Acetylcholine↗
PubMed1994

Effect of arachidonic acid on [3H]D-aspartate outflow in the rat hippocampus.

The aim of this study was to investigate the effect of arachidonic acid on [3H]d-aspartate outflow in rat hippocampus synaptosomes and slices. Arachidonic acid 1) increased basal outflow of [3H]d-aspartate in both synaptosomes and slices, and 2) increased K(+)-evoked overflow in slices but not in synaptosomes. The latter effect was dependent (at least in part) on arachidonic acid metabolism, most likely mediated by lipo-oxygenase metabolites and free radical production. It was prevented by nordihydroguairetic acid but not by indomethacin, and was significantly reduced by free radical scavengers (superoxide-dismutase and catalase). This effect was dependent upon stimulation since it could not be observed after a continuous perfusion of arachidonic acid in the absence of stimulation. Furthermore, it was long-lasting since a 30 min perfusion of arachidonic acid was sufficient to exert a significant effect on a stimulation following termination of the application.

Animals↗
PubMed1994

Fluorimetric determination of electrically evoked increase in intracellular calcium in cultured cerebellar granule cells.

A technique is described to measure the electrically evoked increase in intracellular calcium in cerebellar granule cells cultured on glass coverslips and preloaded with FURA-2. To minimize light scattering, the coverslip containing the granules was placed in the fluorimeter cuvette at a 30 degrees angle to the exciting light beam. The cuvette was provided with 2 platinum electrodes so as to stimulate the neurons with a tangential field. The [Ca2+]i transients were maximized by omitting Mg2+. The fluorescence peaks were directly related to the pulse (1 ms, 100 mA) frequency and to the train length. The responses were completely tetrodotoxin- and [Ca2+]o-dependent and could be replicated 5-6 times at 5-min intervals. At the stimulation rate of 20 Hz for 5 s, a condition ensuring submaximal peaks, the [Ca2+]i rose from the basal levels of 41 +/- 2.7 nmol/l to 89.6 +/- 5.8 nmol/l. The participation of various membrane channels in the electrically induced [Ca2+]i increase was demonstrated. 4-Aminopyridine (1 mM) increased the height of the peaks to 240%. Both nifedipine (10 microM) and omega-conotoxin (1 microM) reduced the transients by about 25%. The residual response (in the absence of Mg2+) depended mostly on the release of endogenous glutamate as it proved sensitive to NMDA, AMPA and t-ACPD receptor antagonists. Since a technique to measure the electrically evoked release of D-[3H]aspartate is presently available, the parallel determination of release and of [Ca2+]i in twin populations of cultured granule cells is possible.

Animals↗
PubMed1994

Excitatory amino acids (EAAs) stimulate phosphatidylinositol turnover in adult rat striatal slices: interaction between NMDA and EAA metabotropic receptors.

The effect of excitatory amino acids (EAAs) on phosphatidylinositol (PI) turnover in adult rat striatal slices was investigated. Quisqualic acid (QA), alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), kainic acid (KA), ibotenic acid (IBO) and N-methyl-D-aspartic acid (NMDA) maximally increased inositol phosphate (IP) formation at 10 microM while trans-1-amino-cyclopentane-1,3-dicarboxylic acid (ACPD) was maximally effective at 100 microM. The NMDA channel blocker dizolcipine (MK-801) counteracted the effect of NMDA 10 microM and IBO 10 microM while it potentiated that of IBO 100 microM and IBO 1000 microM. Conversely, the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) prevented the effect of AMPA and KA and reduced that of QA (all at 10 microM). Lowering extracellular Ca2+ concentrations ([Ca2+]0) differentially affected the PI response to EAAs. The ACPD 30 microM effect was unchanged at low [Ca2+]0 (but abolished when EGTA 2 mM was added), while that of ACPD 100 microM was halved in 0.1 mM and almost abolished in a nominally free Ca2+ medium. NMDA 10 microM and AMPA 10 microM were ineffective at low [Ca2+]0 while NMDA 100 microM, ineffective in a 1.2 mM Ca2+ medium, strongly stimulated IP formation in 0.1 mM Ca2+ but not in a nominally free Ca2+ medium. The effect of NMDA on EAA metabotropic receptor agonist stimulated PI turnover was also studied. NMDA 10 microM potentiated the effect of ACPD 30 microM. This positive cooperation persisted at low [Ca2+]0 but not in the presence of EGTA. Conversely, NMDA 100 microM prevented the effect of ACPD 100 microM. This negative interference was reversed when Ca2+ was omitted from the medium. This study shows that in the adult rat striatum both EAA metabotropic and ionotropic receptor activation increases IP formation. A positive and negative interaction between NMDA and metabotropic receptor activation was also found to regulate PI turnover. The role of [Ca2+]0 in subserving the PI response to EAAs was made evident.

Amino Acids↗
PubMed1994

Facilitation of GABA release by neurotensin is associated with a reduction of dopamine release in rat nucleus accumbens.

The main aim of the present study was to investigate the effects of local perfusion with the tridecapeptide neurotensin on extracellular GABA and dopamine levels in the nucleus accumbens of the halothane-anaesthetized rat, using in vivo microdialysis. In an initial set of characterization studies we examined the Na+ dependence of neurotransmitter release by local perfusion with ouabain, veratridine and tetrodotoxin. Local perfusion with the Na+ ATPase inhibitor ouabain (10 microM) or the Na+ channel agonist veratridine (20 microM) perfused into the nucleus accumbens increased both extracellular GABA and dopamine levels. The Na+ channel antagonist tetrodotoxin (1 microM) consistently decreased (24% of basal) dopamine levels, while even at 10 microM it did not affect GABA. However, tetrodotoxin (10 microM) abolished the veratridine-induced increase in both GABA and dopamine, demonstrating that Na(+)-dependent neuronal activity is involved in this release mechanism. In a second set of experiments a hypothesis for a functional link between neurotensin, dopamine and GABA in the medial nucleus accumbens was tested. Towards this aim, the effects of local perfusion with a high 1 microM concentration of neurotensin into the nucleus accumbens increased both GABA (210% of basal value) and dopamine (145% of basal) release. However, a low (10 nM) concentration of neurotensin again increased GABA release (160% of basal), but decreased that of dopamine (75% of basal value). Furthermore, the local perfusion with the GABAA receptor antagonist bicuculline abolished the neurotensin (10 nM) induced inhibition of dopamine release without affecting the increase in GABA release. These findings suggest that neurotensin modulates both GABA and dopamine neurotransmission in the nucleus accumbens.(ABSTRACT TRUNCATED AT 250 WORDS)

3,4-Dihydroxyphenylacetic Acid↗
PubMed1994

Induction of heparin-binding epidermal growth factor-like growth factor mRNA by protein kinase C activators.

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a potent smooth muscle cell mitogen of macrophage origin. To determine whether the HB-EGF gene is transcribed and regulated in mesangial cells, we measured HB-EGF mRNA levels in cultured rat mesangial cells by RNA blot analysis. A 2.5-kb HB-EGF mRNA was detected in unstimulated mesangial cells. The protein kinase C activator 12-O-tetradecanoylphorbol 13-acetate (TPA) increased HB-EGF mRNA levels by 15-fold in mesangial cells, and this induction of HB-EGF mRNA by TPA was both time- and dose-dependent. HB-EGF mRNA could also be stimulated by 10% fetal calf serum, ionomycin, thrombin, and endothelin-1. Staurosporine, a protein kinase C inhibitor, abolished the induction of HB-EGF mRNA by TPA and serum. To determine whether HB-EGF is mitogenic for mesangial cells, we transfected COS cells with HB-EGF expression plasmids. Culture medium from COS cells transfected with these plasmids increased 3H-thymidine incorporation in mesangial cells in a dose-dependent manner. To our knowledge, this is the first report that HB-EGF is expressed in renal cells. This inducible transcription of HB-EGF suggests that it may have an autocrine role in mesangial cell proliferation in kidney disease.

Alkaloids↗
PubMed1994

Murine model of accelerated transplant arteriosclerosis.

To define the role of specific gene deletions and mutations in the development of transplant arteriosclerosis, we generated an accelerated model of the disease in mice. Carotid arteries were transplanted between B.10A(2R) (H-2h2) donor mice and C57BL/6J (H-2b) recipients and compared with arteries isografted between H-2b mice. Immunosuppressive drugs were not used. Within 7 days, the allografted carotid artery formed a neointima composed of mononuclear leukocytes (CD45+) that were predominantly monocytes or macrophages (ie, CD11b+ cells with single-lobed nuclei). CD4+ and CD8+ cells were present as well. By 30 days, the neointima became exuberant, and mononuclear leukocytes were largely replaced by smooth muscle cells. Cells staining for proliferating-cell nuclear antigen were abundantly present in the intima at both early and late time points, indicating the proliferation of mononuclear leukocytes and smooth muscle cells. The area of the intima increased from day 7 to day 30 (P < .0005), as did the number of nuclei (P = .0005), but the density of the nuclei decreased (P = .02), suggesting the formation of extracellular matrix. Six of the eight isografts formed no neointima, and in samples from the remaining two, a single layer of smooth muscle neointimal cells covered just a portion of the vessel circumference. This model, which reproduces many of the features of human transplant arteriosclerosis but at an accelerated pace, should prove useful for determining the roles in transplant arteriosclerosis of genes that code for components of immunologic and inflammatory responses.

Animals↗
PubMed1994

Ethnographic approach to community organization and health empowerment.

The purpose of this article is to address pertinent issues relative to the association between community organization and health empowerment methods in ethnic communities of colour. It seeks to address these issues by utilizing ethnographic procedures for documenting community health concerns and by advocating for empowerment for people of colour and their participation in coalition partnerships. Increasingly the importance of citizen participation in the planning, assessment, and implementation of community-based health initiatives has been identified as essential for effective health promotion and disease prevention programs. This article argues for the utility of a community organization approach for achieving health empowerment, and subsequently decreasing the excess deaths in communities of colour. The interface of ethnographic procedures, community organization, and development of community-owned action plans for programming health interventions is discussed.

Black or African American↗
PubMed1994

Antiphospholipid antibodies and risk of intrauterine late fetal death.

STUDY OBJECTIVE: Goal of the study was to analyze the relationship between anticardiolipin antibodies, lupus anticoagulant and the risk of intrauterine late fetal death. DESIGN: A case-control study was conducted in a network of general and teaching hospitals in northern Italy. Cases studied were 99 women (median age 27 years), without clinical evidence of systemic lupus erythematosus or other immunological disorders who had an 'unexplained' intrauterine fetal death at or after the 20 weeks of gestation. The control subjects were 85 women (median age 28 years) who gave birth at term (> 37 weeks gestation) to healthy infants on randomly selected days at the same hospitals where cases had been identified. RESULTS: The presence of lupus anticoagulant was detected in four of the 99 cases (4%, 95% confidence interval 2%-15%) and none of the 85 controls. A total of 10 out of the 89 cases (11%, 95 confidence interval 6%-23%), but none of the 79 controls for whom anticardiolipin antibodies value was available had elevated anticardiolipin antibodies; this difference was statistically significant (chi 2(1) = 9.38, p < 0.01).

Adolescent↗
PubMed1994

[Lymph-node inflammatory pseudotumor with granulomatous component. Report of a case and review of the literature].

A case of inflammatory pseudotumor of lymph node in a 65 year-old man is described. The case is striking because of a granulomatous component within the lesion, a finding unpreviously described. This lesion, benign by nature, should not be misinterpreted as a neoplastic process, especially lymphomas or soft tissue tumors; problems related to the differential diagnosis are also discussed.

Aged↗
PubMed1994

[Dementia in Friuli-Venice Giulia: hospital diagnosis].

Discharge diagnoses made in the large hospitals of Friuli-Venezia Giulia during a 3-year period (1989-91) were collected. Diagnoses with ICD-9 codes 290, 290.0-4, 290.8-9, 331, 331.0-9, and 437.0 were selected, and analyzed. Discharge diagnoses including one of the above ICD-9 codes were found in 6,647 cases. ICD-9437.0 (brain arteriosclerosis) was by far the most frequent code (4,731 cases). When the present results are examined in the light of literature data as well as of previous research performed at the Monfalcone Hospital, it emerges that in the hospitals of Friuli-Venezia Giulia, dementia is a strongly underestimated condition. In addition the present data suggest that in these hospitals most dementia cases are misdiagnosed as vascular dementias.

Aged↗
PubMed1994

[Malignant mesothelioma: various key aspects].

Mesothelioma deserves particular attention for various reasons: 1) a dramatic increase in the incidence of this tumor has been observed in various countries; 2) diagnosis is not rarely problematic; 3) asbestos-related mesothelioma represents a nearly unique model in human cancerogenesis. Latency periods (defined as intervals between first exposure to asbestos and death) differ from one occupational category to another. These differences seem to depend not only on the intensity of the exposure, but also on other unidentified factors. The study of the mechanisms influencing the length of latency periods could open a way in preventing mesothelioma.

Asbestos↗