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Biomedical subjects

F Bianchi

Publications and source records attributed to F Bianchi.

At least 91 records · Page 5Linked to original sources
PubMed1994

Microglia in invertebrate ganglia.

The results of this study lend strong support to the concept of the existence in insects and molluscs of a distinctive class of neuroglial cells comparable to vertebrate microglia. The evidence presented is as valid as that used in reference to the separate status of vertebrate microglia--i.e., the demonstration of a close structural and functional relationship of these cells with cells of the immune system. As in vertebrates, the excision of ganglia from three invertebrate species (the molluscs Planorbarius corneus and Mytilus edulis and the insect Leucophaea maderae) and their maintenance in incubation media led to an exodus of small cells and their accumulation in the culture dish. During this process, they underwent conformational changes from stellate to rounded, and then to more or less ameboid, comparable to those indicative of the process of activation in the animals' immunocytes. Functional characteristics which these translocated microglia-like cells share with immunocytes are motility, phagocytotic activity, and adherence to the culture dish. Furthermore, the two cells have certain biochemical features in common--e.g., the presence of certain cytokines and (at least in Planorbarius) that of corticotropin. An additional phenomenon of particular interest for the classification of microglial elements is their response to morphine. At 10(-6) M, this drug decreases not only the number of cells emerging from the excised ganglia but also the degree of their transformation to the "active" ameboid form. This dose-dependent and naloxone-sensitive effect of morphine on microglial cells parallels that on activated immunocytes of the same species. Corresponding results demonstrating an inhibitory effect of morphine on mobilized microglial cells of the frog Rana pipiens indicate that this relationship between the two cell types under consideration also exists in vertebrates. Binding and displacement experiments with membrane homogenates of microglial cells as well as immunocytes of Mytilus have shown that the effects of morphine on both cell types are mediated by the same special opiate receptor (mu 3).

Animals↗
PubMed1994

Interaction of human P1 and P2 protamines with DNA.

The interaction of two classes of human sperm protamines, P1 (HP1) and P2 (HP2, HP3, HP4), with DNA was investigated. Gel mobility shift assays with a range of DNA fragments of defined sizes show that, whatever its length, all the DNA is complexed with protamines at arginine to phosphate ratio of 0.1. Further addition of protamine molecules leads to a precipitation of the protamine-DNA complexes for arginine-phosphate ratio > or = 1.2. Fluorescence studies using the dye Hoescht 33258 as a fluorophore and DNAase I footprinting experiments suggest that P1 and P2 protamines bind at the DNA surface without apparent location in the minor or major groove of DNA. No differences in protamine-DNA interaction were observed between the two classes of human protamines P1 and P2. Moreover the binding to DNA was not influenced by the presence of zinc which induces the formation of a zinc-finger structure in protamine P2.

Binding, Competitive↗
PubMed1994

Increased risk of hepatocellular carcinoma development in patients with cirrhosis and with high hepatocellular proliferation.

The immunohistochemical determination of the accessory protein of DNA-polymerase delta (PCNA), a marker of an early S-phase of the cell cycle, was used to evaluate cell proliferation retrospectively in formalin-fixed, paraffin-embedded liver biopsy sections in a group of patients with cirrhosis of similar age and duration of follow up, and with no evidence of hepatocellular carcinoma (41), including 17 patients with and 24 without hepatocellular carcinoma appearance during follow up. Proliferation was expressed as total (PCNA-TOT) and strongly (PCNA-STRO) positive nuclei per 1000 hepatocytes. The presence of dysplasia was also recorded. Histological findings and biochemical data, at the time of liver biopsy, were compared in the two groups. While total PCNA positivities were not significantly different in the two groups, strong reactivity was significantly higher in patients who eventually developed hepato-cellular carcinoma (median 0.7 vs 2.6). Univariate analysis of histological and biochemical data at the time of biopsy, followed by a stepwise regression study, showed that the significant parameters for a time-dependent disease-free state were, in decreasing order: cholesterol, PCNA-STRO, PCNA-TOT and alpha foeto-protein. Other clinical, biochemical and histological parameters, including dysplasia, provided no further information. From these data, hepatocellular proliferation can be evaluated in patients with cirrhosis with a currently available technique. Patients with high cell proliferation are at increased risk of developing hepatocellular carcinoma and may require differentiated follow up.

Adult↗
PubMed1994

Effect of low molecular weight heparan sulphate on angiogenesis in the rat cornea after chemical cauterization.

Vascularization of the cornea occurs in many pathological conditions and can result in loss of visual acuity. It is also thought that vascularization predisposes the cornea to reject grafts by facilitating the detection of foreign antigens in donor material. A rat corneal assay for angiogenesis was adopted in the present study to evaluate the possible angiostatic activity of a low molecular weight heparan sulphate (LMW-HS). Corneal lesions were induced by chemical cauterization at 2 mm from the corneoscleral limbus. Rats were randomized to receive two drops/eye four times daily, for 6 days, of a solution of LMW-HS in vehicle (2.5% carboxymethylcellulose), heparin, heparin plus hydrocortisone, or vehicle alone. After a 6 day-treatment period, the eyes were perfused with india ink and the degree of neovascularization was evaluated. In rats treated with vehicle alone a dense vascular network extending from the corneoscleral limbus to the cauterized site was observed; on the contrary, a markedly reduced vascular network was evidenced in animals treated with LMW-HS. The distribution of basic fibroblast growth factor (bFGF) in the cauterized cornea was also evaluated by using an immunohistochemical method. A marked bFGF immunoreactivity was demonstrated in corneal epithelium and stroma of control rats 12-48 hours after the cautery. These results lead to the assumption that LMW-HS could be used in ophthalmology to inhibit corneal neovascularization.

Animals↗
PubMed1994

Hepatocellular expression of HLA-A, B, C molecules predicts primary response to interferon in patients with chronic hepatitis C.

Primary response rate to alpha-interferon (IFN) is about 50% in patients with chronic hepatitis C. Criteria for predicting a positive primary response are lacking. HLA-A,B,C molecule expression is known to be stimulated by viral infections. In 36 consecutive interferon-treated anti-HCV positive patients with an available frozen liver biopsy sample, the predictive value of liver HLA-A,B,C expression, and of histologic, clinical, and biochemical parameters was evaluated. Response to treatment was defined by normalization of transaminases, and disappearance of serum HCV-RNA within 3 months. According to these criteria, 17 patients were classified as nonresponders and 19 were classified as responders. The pattern of HLA-A,B,C hepatocellular positivity varied from normal (negative or occasional faint staining of hepatocellular membranes) to diffuse, strong "honeycomb" positivity. The highest scores of positivity were found in nonresponder patients. The discriminant capacity of HLA-A,B,C scores of positivity was compared with clinical, biochemical and histologic parameters by discriminant analysis. HLA-A,B,C expression was found to be the main discriminant parameter, in addition to alkaline phosphate (ALP) and gamma-glutamyl-transpeptidase (GGT) which added little additional information. The higher hepatocellular expression of class I MHC molecules in nonresponder cases may reflect a different viral effect on hepatocytes, which is induced by different HCV genotypes or levels of viremia. From a clinical point of view, the pretreatment HLA-A,B,C pattern of positivity represents a powerful tool in the selection of patients for interferon treatment.

Adult↗
PubMed1994

Interaction of mammalian sperm nuclear protamines and peptides derived thereof with immobilized zinc.

The interaction of mammalian and human protamines with zinc was studied by immobilized metal ion affinity chromatography (IMAC). The affinity of protamines containing blocked cysteine residues was found to correlate in part with the presence and number of histidine residues in the protamine structure: absence or low affinity of P1 protamines containing 0 or 1 histidine residue; high affinity of human P2 protamine containing 9 histidines. Nevertheless a fraction strongly retained on an IDA-Zn(II) column was observed for P1 protamines with one histidine in the N-terminal sequence (ram and boar protamines). The strong binding was found to be related to the presence of tyrosine, serine and threonine closely spaced to the histidyl side chain. In the case of human protamine P2, the strong retention on the IDA-Zn(II) column seems to result from the additive contribution of all the histidine residues of the molecule. Thus, strong retention of protamines in IMAC seems to depend on an additive contribution of amino-acid side chains: histidine, tyrosine, serine, threonine and perhaps arginine. The high affinity of protamines, more especially P2 protamines, for zinc suggests that this metal ion could play a role for their correct folding and binding to DNA.

Amino Acid Sequence↗
PubMed1994

Intermittent cyclic therapy with etidronate in the prevention of corticosteroid induced bone loss.

OBJECTIVE: To assess the potential efficacy of intermittent cyclic therapy (ICT) with etidronate in the treatment of patients with corticosteroid induced osteoporosis. METHODS: Cohort study in a tertiary care university affiliated hospital in corticosteroid treated patients, with polymyalgia rheumatica, asthma, systemic lupus erythematosus, rheumatoid arthritis, or temporal arteritis, examining the effects of ICT etidronate. Patients were included if they were taking corticosteroids for a minimum of one year. Comparison patients were those who had been taking corticosteroids for a minimum of one year and who had not been treated with etidronate or other medication which might alter bone metabolism. A total of 68 patients were included from 253 considered. The mean (SD) dose of prednisone in the ICT etidronate treated patients was 9.3 (6.2) mg and in the comparison patients 9.4 (5.9) mg. The duration of prednisone therapy was 7.8 (5.8) years and 3.4 (4.2) years, respectively (p2 < 0.001). An analysis of covariance demonstrated that this difference did not alter our primary outcome measure. The primary outcome measure was the difference in the percentage change from baseline to one year of followup in bone mineral density (BMD) of the lumbar spine between treatment and comparison groups. RESULTS: ICT etidronate resulted in a statistically significant and clinically important increase in BMD. The BMD of the lumbar spine increased by 3.82% (0.65%), [95% confidence interval (CI), 2.51 to 5.14%] in the 35 ICT etidronate treated patients and decreased by 1.78% (0.76%), [95% CI, -3.34 to -0.23%] in the 33 comparison patients after 12 months (p2 < 0.0001). CONCLUSIONS: ICT etidronate prevented loss of vertebral bone density in patients with corticosteroid induced osteoporosis. Controlled, double blind, prospective trials with longer followup are needed to confirm these results and to demonstrate that increases in bone mass translate into decreased fracture rates.

Adrenal Cortex Hormones↗
PubMed1994

Multiple DNA variant association analysis: application to the insulin gene region in type I diabetes.

Association and linkage studies have shown that at least one of the genetic factors involved in susceptibility to insulin-dependent diabetes mellitus (IDDM) is contained within a 4.1-kb region of the insulin gene. Sequence analysis has led to the identification of 10 DNA variants in this region that are associated with increased risk for IDDM. These variants are in strong linkage disequilibrium with each other, and previous studies have failed to distinguish between the variant(s) that cause increased susceptibility to IDDM and others that are associated with the disease because of linkage disequilibrium. To address this problem, we have undertaken a large population study of French diabetics and controls and have analyzed genotype patterns for several of the variant sites simultaneously. This has led to the identification of a subset consisting of four variants (-2733AC, -23HphI, -365VNTR, and +1140AC), at least one of which appears to be directly implicated in disease susceptibility. The multiple-DNA-variant association-analysis approach that is applied here to the problem of identifying potential susceptibility variants in IDDM is likely to be important in studies of many other multifactorial diseases.

Diabetes Mellitus, Type 1↗
PubMed1994

[Identification of ischemic and/or viable myocardium in early post-infarction period using echocardiographic imaging technique. Comparison of 2 tests: echo-dipyridamole and echo-dobutamine].

AIM OF THE STUDY: To compare two stress tests: Dipyridamole-echocardiography (ECHO-DIP) and Dobutamine-echocardiography (ECHO-DOB) with angiographic data (still "gold standard") in early postinfarction period in order to identify ischemic and/or viable myocardium (considering the echocardiographic follow-up as "gold standard"). METHODS: 40 consecutive patients (pts), mean age 56, at their first uncomplicated acute myocardial infarction (AMI) treated with thrombolytic agents were studied. All underwent coronary angiography. RESULTS: The ECHO-DIP test resulted positive in 17 pts for transient regional asynergy (homozone 13/17; heterozonal positivity 4/17). The mean basal Wall Motion Score Index (WMSI) was 0.46 +/- 0.30 and at asynergy was 0.58 +/- 0.33 (p < 0.001). The ECHO-DOB test resulted positive in 20 pts; mean basal WMSI was 0.42 +/- 0.31 and at asynergy 0.55 +/- 0.35 (p < 0.001). Both tests were positive in 14 pts; the site of regional asynergy was the same in each test. During ECHO-DOB hypercinesia appeared in 27/39 pts (WMSI form basal 0.42 +/- 0.31 to 0.22 +/- 0.21 p < 0.001). Recovery of contractile function seems to identify viable myocardium: viable tissue shows early functional recovery during ECHO-DOB infusion. In 14 pts it remained until the end of the test, and in 12 it was transient, denoting the presence of myocardium "at risk". Remote (3- or 6-month) clinical and echocardiographic follow-up were carried out in all pts (25 undergoing medical therapy and 15 after PTCA or coronary bypass). In 26 pts with hyperkinesia at ECHO-DOB, basal echocardiogram revealed improvement of WMSI from 0.42 +/- 0.31 to 0.32 +/- 0.29 (p < 0.001). CONCLUSIONS: "Passive" ECHO-stress tests in the early postinfarction period are easy to perform and free of major risks, they allow pts at risk due to residual ischemia to be revealed with a high degree of specificity and sensitivity. The improvement of kinesis during inotropic stimulus of Dobutamine suggests stunned or hibernating myocardium.

Adult↗
PubMed1993

Omphalocele and gastroschisis: a collaborative study of five Italian congenital malformation registries.

During 1984-1989, 116 cases of omphalocele and 42 cases of gastroschisis were detected among 736,760 consecutive births in the area covered by five Italian congenital malformation registries. The prevalence rate was 1.6 per 10,000 for omphalocele and 0.6 per 10,000 for gastroschisis. Three additional cases were detected among spontaneous abortions, giving a total of 117 cases of omphalocele and 44 of gastroschisis. No variations in prevalence rates were observed among registries. A cluster of omphalocele was found in 1989 in Firenze. All cases were sporadic except for one infant with two sibs with Beckwith-Wiedemann syndrome. A predominance of male infants was observed for both defects. This study confirms the very young maternal age for isolated gastroschisis as compared to that for omphalocele and controls. Birth weight and the percentage of small-for-date is different among isolated gastroschisis, omphalocele and controls. Associated anomalies occurred in 45 cases of omphalocele and 11 cases of gastroschisis. Our data confirm the association of omphalocele with trisomies 13 and 18. Twelve cases of omphalocele and gastroschisis with associated limb defects were classified as limb body wall complex. The possible differences in etiopathology between omphalocele and gastroschisis, both isolated and associated, are discussed.

Abnormalities, Multiple↗
PubMed1993

Laser nephelometric evaluation of albumin, IgG and alpha 2-macroglobulin: applications to the study of alterations of the blood-brain barrier.

Cerebrospinal fluid and serum levels of albumin, immunoglobulin G and alpha 2-macroglobulin were determined by laser nephelometer in various pathological conditions: Guillain-Barré syndrome amyotrophic lateral sclerosis, lumbar disc herniation. These proteins are different due to their molecular weight, spacial conformation, CSF and serum concentrations and their CSF/serum quotient reflects the status of the blood-brain barrier. In the subjects group comparisons, albumin quotient and IgG quotient show a significant differentiations. The linear regression of albumin quotient compared to alpha 2-macroglobulin quotient behaves differently in the individual groups. The protein CSF/serum quotients are helpful in distinguishing the causes of alterations in the blood-brain barrier.

Adolescent↗
PubMed1993

In vitro morpho-functional analysis of pancreatic islets isolated from the domestic chicken.

The technique whereby islets were isolated from the pancreas of chicken and their in vitro histological and functional characterization are described in this paper. Our isolation procedure consisted of two steps: initially the pancreas removed from the chicken was perfused with a 2% solution of collagenase and enzymatic digestion was then carried out using the same solution. After this, density gradient separation was performed on the digested tissue, by means of differing Histopaque solutions: at the end of the separation, the islets were studied by light microscopy after treatment with diphenylthiocarbazone, which selectively stains beta-cells, and by scanning and transmission electron microscopy. The results reported here show the pattern closely resembled that encountered when islets were studied in situ. The beta-cells of the islets proved in vitro to preserve their functional capability of producing insulin even after stimulation with glucose or arginine.

Animals↗
PubMed1993

Involvement of basic fibroblast growth factor in suramin-induced inhibition of V79/AP4 fibroblast cell proliferation.

The V79/AP4 Chinese hamster fibroblasts were densely stained with the anti-basic fibroblast growth factor (bFGF) antibody demonstrating an endogenous production of the peptide. The in vitro proliferation of these cells was stimulated by exogenous bFGF and the maximum growth (259% increase in 3H-thymidine incorporation into DNA) was reached with bFGF 10 ng ml-1. Inhibition of bFGF-mediated mitogenic pathway was obtained with a 15-mer antisense oligodeoxynucleotide targeted against bFGF mRNA and with suramin, a drug which blocks the biological activity of heparin-binding growth factors. bFGF antisense oligomer reduced the synthesis of DNA by 79.5 and 89.5% at 20 and 60 microM, respectively; this effect was reversed by the addition of exogenous bFGF to the culture medium. A short-term exposure to suramin 300 micrograms ml-1 produced a modest reduction in 3H-thymidine incorporation but suppressed the mitogenic effect of bFGF on V79/AP4 cells. In cells treated with suramin 300 micrograms ml-1 the drug concentration increased linearly over 3 days, reaching 13.15 micrograms mg-1 of protein; cell proliferation was inhibited in a dose-related manner as evaluated by the colony formation assay (IC50: 344.22 micrograms ml-1) and by the number of mitoses observed in culture. Furthermore, the drug induced ultrastructural alterations, consisting of perinuclear cisternae swelling, chromatin condensation, nucleolar segregation and cytoplasmic vacuolations. These findings demonstrated that the endogenous production of bFGF plays an important role in V79/AP4 fibroblasts proliferation, and the inhibition of bFGF-mediated mitogenic signalling with bFGF antisense oligomer or suramin is an effective mean of reducing cell growth.

Animals↗
PubMed1993

Occurrence and distribution of insulin receptor-like immunoreactivity in molluscan brains.

Insulin receptor-like immunoreactivity (IR) was investigated in the central ganglia of different gastropod molluscs using a monoclonal antiserum raised against an epitope of the human placental insulin receptor. A well detectable and clear location of immunoreactive material was mainly found in the CNS of the freshwater snails Planorbarius corneus and Lymnaea stagnalis. This evidence correlates quite suggestively with the occurrence in these snails of a molluscan insulin peptide (MIP) previously shown. The widespread and discrete distribution of IR over a variety of physiologically distinct regions of P. corneus and L. stagnalis ganglia argues that these "receptors" may modulate multiple functions within the CNS.

Animals↗