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Biomedical subjects

R Bianchi

Publications and source records attributed to R Bianchi.

At least 127 records · Page 7Linked to original sources
PubMed1996

Serum tumour-associated trypsin inhibitor (TATI) and renal function.

Tumour-associated trypsin inhibitor (TATI) is a low molecular weight (MW) protein employed as a tumour marker. The blood levels of some low MW proteins increase in renal insufficiency. The aim of this study is to evaluate the relationship between serum TATI and glomerular filtration rate (GFR). Serum beta 2-microglobulin (beta 2M) and plasma creatinine were also determined. The decrease of GFR was accompanied by an increase in the other parameters. The maximum increase of TATI was from a mean basal value of 8.51 +/- 5.58 micrograms l-1 in subjects with normal renal function to 107.27 +/- 63.34 micrograms l-1 in patients with renal failure; beta 2M increased from 1.45 +/- 0.38 to 11.16 +/- 5.73 mg l-1 and creatinine from 1.05 +/- 0.17 to 5.07 +/- 1.93 mg dl-1. The increase in TATI occurs sooner and is greater than that of beta 2M and of creatinine. These results suggest that TATI is handled by the kidney. It is sensitive marker of reduction in renal function. When TATI is used as a tumour marker, renal function must be taken into account in the evaluation of the results.

Adolescent↗
PubMed1996

Immunohistochemical study of neurons in the rat abducens nucleus that project to the flocculus.

The neurons of the rat abducens nucleus that project to the flocculus of the cerebellum were studied by double labelling using the retrograde transport of horseradish peroxidase (HRP) and choline acetyltransferase (ChAT) immunohistochemistry. Double-labelled cells were present bilaterally in the dorsal and dorsomedial zones of the cranial pole of the nucleus. They represented about half of the total number of HRP-positive neurons. These findings show the existence of a bilateral projection from the abducens nucleus to the flocculus which uses acetylcholine as a neurotransmitter. This projection could be part of the system of the nerve circuits through which the cerebellum modulates visual activities.

Abducens Nerve↗
PubMed1995

O6-alkylguanine-DNA alkyltransferase attenuates triazene-induced cytotoxicity and tumor cell immunogenicity in murine L1210 leukemia.

Methylating and chloroethylating triazene compounds (TZCs) are effective antitumor agents in murine leukemias and can induce the appearance of novel antigens in leukemic cells (chemical xenogenization). Recently, it has been shown that TZCs might have a role in the treatment of patients affected by acute myelogenous leukemias that express low levels of the DNA repair enzyme, O6-alkylguanine-DNA alkyltransferase (OGAT). In this report, we have evaluated the role of this DNA repair enzyme in the leukemic cell response to the xenogenizing and cytotoxic properties of TZCs. OGAT-deficient murine leukemic L1210 cells were transfected with a recombinant ecotropic retrovirus containing the coding region for the human OGAT protein. Selected clones expressed the human OGAT transcript and had greatly increased OGAT activity. Compared to OGAT-deficient cells, OGAT-expressing cells were considerably more resistant to the xenogenizing properties of 1-(p-chlorophenyl)-3,3- dimethyl-triazene, measured in terms of leukemia graft rejection, and were less susceptible to the cytotoxic activity of the TZCs 8-carbamoyl-3-methyl-imidazo [5,1-d]-1,2,3,5-tetrazin-4(3H)-one and 8-carbamoyl-3-(2-chloroethyl)imidazo [5,1-d]-1,2,3,5-tetrazin-4(3H)-one. These data suggest that methylation of the O6 position of guanine is involved in the appearance of increased tumor immunogenicity after exposure to methylating TZC and that OGAT is able, at least in part, to counteract the cytotoxic effects of methylating and chloroethylating agents.

Animals↗
PubMed1995

Excitatory synaptic potentials dependent on metabotropic glutamate receptor activation in guinea-pig hippocampal pyramidal cells.

1. Intracellular and extracellular recordings of CA1 and CA3 neurones were performed in guinea-pig hippocampal slices to examine synaptic activities dependent on metabotropic glutamate receptors (mGluRs). 2. Long burst activities were elicited by 4-aminopyridine in the presence of ionotropic glutamate receptor and GABAA receptor blockers (6-cyano-7-nitroquinoxaline-2,3-dione and 3-(RS-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid, and picrotoxin). Long bursts were also elicited by alpha-dendrotoxin. 3. Long bursts consisted of a 5-25 s depolarization with overriding action potentials and occurred rhythmically at intervals ranging from 1 to 20 min. Long bursts were generated in a population of CA3 neurones and the synchronized output elicited long bursts in CA1 cells. Depolarizing potentials underlying long bursts in CA1 cells had a reversal potential of -14.8 +/- 5.1 mV. 4. Long burst-associated depolarizations in CA1 neurones were suppressed by local application of L-(+)-2-amino-3-phosphonopropionic acid (L-AP3) and of the phenylglycine derivatives (+)-alpha-methyl-4-carboxyphenylglycine ((+)-MCPG), S-4-carboxyphenylglycine (S-4CPG) and S-4-carboxy-3-hydroxyphenylglycine (S-4C3HPG). (-)-MCPG or atropine application did not affect the long burst-associated depolarization. 5. Bath perfusion of (+)-MCPG (0.5 mM), S-4CPG (0.5 mM), S-4C3HPG (0.5 mM) or L-AP3 (1 mM) blocked the occurrence of long bursts. 6. The results suggest that the long burst-associated depolarizations are synaptic potentials dependent on mGluR activation. Activation of mGluRs may also be involved in the generation of synchronized long bursts in the CA3 region.

Action Potentials↗
PubMed1995

Multiple point mutations in an endogenous retroviral gene confer high immunogenicity on a drug-treated murine tumor.

Exposure in vivo of murine L5178Y lymphoma cells to cytoreductive triazene derivatives leads to the generation of immunogenic variant lines expressing new transplantation Ags recognized by CTL. In one such clonal variant (clone D), at least one subset of T cell neoepitopes are provided by proteins previously shown by serology to be products of endogenous retroviral env sequences. We report here on characterization of PCR-amplified gp70 env genes in clone D. Relative to known gp70 sequences in parental cells and in current databases, one gp70 sequence presented four distinct nucleotide changes, two of which were apparently unique to clone D DNA and cDNA upon differential hybridization analysis. Transfection experiments with the entire gp70 gene or subgenic fragments encompassing a single putative mutation showed that products of the mutated env gene or fragments may confer immunogenicity in vivo and susceptibility in vitro to lysis by clone D-primed, H-2Kd- or H-2Ld-restricted CTL. By skin test assay of mice primed with either clone D or three mutated synthetic peptides, evidence was obtained that amino acid substitutions at the relevant positions of the gp70 protein may produce immunogenic T cell epitopes and that these epitopes are expressed in vivo by clone D. These data point to the role of mutated retroviral tumor peptides as rejection Ags in histocompatible hosts.

Amino Acid Sequence↗
PubMed1995

Altered tissue degradation and distribution of atrial natriuretic peptide in patients with idiopathic dilated cardiomyopathy and its relationship with clinical severity of the disease and sodium handling.

BACKGROUND: Atrial natriuretic peptide (ANP) has been suggested to play an important role in heart failure, preserving cardiorenal homeostasis through maintenance of the sodium balance and inhibition of the detrimental effects of the neurohormonal vasoconstrictor system. The current study was designed to investigate whether there is a disturbed renewal and distribution of ANP in patients with idiopathic dilated cardiomyopathy (IDC) with differing clinical severity of disease. METHODS AND RESULTS: We used a tracer method to perform a cross-sectional study of 15 IDC patients with differing clinical severity (New York Heart Association functional class I to III), prospectively divided into two groups according to their functional class (group 1, classes I and II; group 2, classes II-III and III). Eleven normotensive, nonobese male volunteers also were studied as a control group. Main ANP kinetic parameters were derived from the disappearance curve of the labeled hormone after the bolus injection of [125I]-labeled ANP. A high-performance liquid chromatography technique was used to separate the radiolabeled hormone in each plasma sample. Patients in group 1 showed higher ANP metabolic clearance rate (MCR) (2731.9 +/- 726.2 mL.min-1.m-2) than patients of group 2 (1718.4 +/- 621.2 mL.min-1.m-2) and control subjects (1873.1 +/- 551.2 mL.min-1.m-2). ANP disposal (MCR) positively correlated with biological hormonal effect (urinary sodium excretion) both in control subjects and in patients. In IDC patients of both groups, however, MCR values were always higher (approximately doubled) than the values found in control subjects at the corresponding sodium excretion. This finding indicates that a reduced ANP biological activity is associated with hormone degradation in patients. Moreover, patients of group 2 showed significantly higher ANP production rates (395.6 +/- 183.8 ng.min-1.m-2) than group 1 (166.0 +/- 139.0 ng.min-1.m-2) and control subjects (130.7 +/- 105.4 ng.min-1.m-2) despite a marked reduction in sodium excretion. Patients with IDC showed a progressive reduction in the total distribution volume (group 1, 19.8 +/- 5.8 L/m2; group 2, 12.7 +/- 6.9 L/m2; control subjects, 27.0 +/- 11.6 L/m2) of the hormone; this probably was due to a reduction in exchanges of ANP with peripheral tissues. CONCLUSIONS: Our study demonstrates a markedly altered degradation and distribution of ANP in patients with IDC, even in those at the early stage of clinical disease (classes I and II, group 1) who have ANP plasma levels in the normal range.

Adult↗
PubMed1995

Annexin II2-p11(2) (calpactin I) stimulates the assembly of GFAP in a calcium- and pH-dependent manner.

Annexin II2-p11(2) (calpactin I) was tested as a potential regulator of GFAP assembly into glial filaments (GF), following the observation that it interacts with GFAP and cosediments with GF in a sedimentation assay. Under conditions where GFAP assembly is reduced, e.g., at pH values > 6.8, annexin II2-p11(2) stimulates GF formation in a Ca(2+)- and dose-dependent manner. Concomitantly, an ever larger fraction of annexin II2-p11(2) can be recovered in GF pellets as the pH is raised from 6.8 to 7.35. Monomeric annexin II also stimulates GFAP assembly, although with a smaller efficacy as compared to annexin II2-p11(2), but does not cosediment with GF to a large extent, whereas p11 neither cosediments with GF nor affects GFAP assembly. On the other hand, the in vitro reconstituted annexin II2-p11(2) heterotetramer mimics native annexin II2-p11(2), and perturbation of the integrity of annexin II2-p11(2) by a mild treatment with alpha-chymotrypsin results in the nearly complete abolition of the stimulatory effect of annexin II2-p11(2) on GFAP assembly. These data suggest that annexin II2-p11(2) might be involved in the regulation of the state of assembly of GF, possibly in concert with other proteins.

Animals↗
PubMed1995

S-100 protein and annexin II2-p11(2) (calpactin I) act in concert to regulate the state of assembly of GFAP intermediate filaments.

S-100 protein and annexin II2-p11(2) were reported to inhibit and to stimulate the assembly of glial fibrillary acidic protein (GFAP), respectively, in a Ca(2+)-dependent manner. Here we show by a number of experimental approaches that S-100 protein contrasts all the effects of annexin II2-p11(2) on GFAP assembly and, conversely, that annexin II2-p11(2) contrasts the inhibitory effects of S-100 protein on GFAP assembly, in a dose-dependent manner in both cases. Altogether, these data suggest that two specific Ca2+ effectors, i.e., annexin II2-p11(2) and S-100 protein, might regulate the state of assembly of glial filaments in a concerted manner.

Animals↗
PubMed1995

CD8+ cell activation to a major mastocytoma rejection antigen, P815AB: requirement for tum- or helper peptides in priming for skin test reactivity to a P815AB-related peptide.

Delayed-type hypersensitivity (DTH) responses, mediated by CD8+ cells and detected by skin test assay, occur in sensitized mice in response to challenge with class I-restricted antigenic peptides of mutagenized (tum-) P815 mastocytoma cells. In contrast, a nonapeptide related to a tumor rejection antigen, P815AB, failed in this study to elicit DTH after sensitization of mice with irradiated tumor cells or adoptive transfer of P815AB-pulsed dendritic cells. Unresponsiveness, however, could be overcome by immunization with tumor cells co-expressing P815AB and tum- antigens. When used for cell pulsing in vitro, a mixture of P815AB and tum- peptides was also highly effective in inducing anti-P815AB reactivity, as was the combined use of P815AB and class II-restricted peptides of tetanus toxin or Plasmodium berghei circumsporozoite protein. While the effector phase of the CD8+ cell-mediated DTH to P815AB was unaffected by the ablation of CD4+ cells, the same treatment, or neutralization of IFN-gamma, negated the induction of reactivity if it occurred at the time of sensitization. Thus, defective activation of CD4+ cells may contribute to the poor immunogenicity of P815AB. Besides providing an insight into the mechanisms of anti-tumor protection induced by tum- cells, these data offer useful information for the design of vaccination strategies against identified tumor antigens.

Amino Acid Sequence↗
PubMed1995

Serum levels of tumor necrosis factor (TNF), soluble receptors for TNF (55- and 75-kDa sTNFr), and soluble CD14 (sCD14) in epithelial ovarian cancer.

The preoperative serum levels of tumor necrosis factor (TNF), soluble receptors for TNF (55- and 75-kDa sTNFr), and soluble CD14 (sCD14) were retrospectively measured in 66 patients with epithelial ovarian cancer and in 59 patients with benign ovarian masses. The preoperative serum TNF and sCD14 levels were higher in patients with epithelial ovarian cancer than in those with benign ovarian disease (P = 0.001 and P < 0.0001, respectively). Among patients with advanced malignancy, preoperative serum TNF and sCD14 correlated with neither the common prognostic variables nor the clinical outcome of patients. The preoperative serum 55- and 75-kDa sTNFr levels were higher in patients with epithelial ovarian cancer than in those with benign ovarian disease (P < 0.0001 and P = 0.02, respectively). Among patients with advanced malignancy, preoperative serum 55- and 75-kDa sTNFr correlated with FIGO stage (IV vs III, P = 0.008 and P = 0.01, respectively) and with the clinical outcome of patients. Among patients followed after surgery and chemotherapy for advanced epithelial ovarian cancer, 55- and 75-kDa sTNFr levels were significantly higher in the samples drawn from patients with clinical evidence of disease when compared to those from patients without clinical evidence of disease; conversely, TNF and sCD14 levels were similar in the two groups. In conclusion, the preoperative serum levels of TNF, 55- and 75-kDa sTNFr, and sCD14 were significantly higher in patients with epithelial ovarian cancer than in those with benign ovarian disease. The measurement of serum TNF and sCD14 seemed to be of limited clinical value for the management of patients with advanced epithelial ovarian cancer. Conversely, the assay of serum 55- and 75-kDa sTNFr might have a potential clinical relevance, for both prognostic purposes and assessment of disease status.

Adult↗
PubMed1995

Production and characterization of rabbit anti-idiotypic antibodies directed against a murine monoclonal anti-B. abortus antibody.

The protective anti-beta abortus monoclonal antibody ISS/32 (Ab1) was used as an immunogen to induce anti-idiotypic antibodies (Ab2) in rabbits. The purpose was to produce and characterize anti-idiotypic antibodies that share conformational similarity with the corresponding bacterial epitope recognized by Ab1. The rabbit anti-IdAb so induced was isolated and affinity-purified. Its specificity for the paratope of Ab1 was determined by evaluating its ability to compete with B. abortus for binding to Ab1 in a competitive ELISA assay. The anti-idiotypic ISS/32 antibodies were able to compete with B. abortus for binding to Ab1 in a dose-dependent manner. Hence, the data indicated that the rabbit anti-Id ISS/32 antibodies reacted with or near the antigen-binding site of Ab1.

Animals↗
PubMed1995

Doppler analysis of uterine blood flow changes in spontaneous and medically induced menopause.

The aim of this study was to compare the uterine blood flow variations induced by chemical castration and spontaneous menopause. Thirty infertile patients were studied in the early follicular phase (day 5-7) and then treated with gonadotropin releasing hormone agonists (GnRH-a). On day 25 from GnRH-a injection, the suppressive effect was checked. The values obtained were compared with those found in 18 postmenopausal women (menopause < 5 years). All the subjects underwent transvaginal ultrasonography, Doppler analysis of uterine arteries, hormonal assay and evaluation of hematological and biochemical parameters. In all infertile patients, the GnRH-a suppressive effect was shown at the 25th day from the injection. Endometrium thickness decreased from 0.6 +/- 0.1 mm to 0.3 +/- 0.1 mm (p < 0.05) and the pulsatility index increased from 2.52 +/- 0.31 to 3.02 +/- 0.25 (p < 0.05). The plasma estradiol level fell from 48.2 +/- 4.4 pg/ml to 13.6 +/- 7.9 pg/ml (p < 0.05). No other hormonal and biochemical parameters were significantly modified by GnRH-a. In postmenopausal women, the values of the studied parameters were similar to those found in the infertile GnRH-a-suppressed patients. These data show that GnRH-a induces vascular modifications similar to those induced by early post-menopause and that both are probably exclusively related to hypoestrogenism.

Adult↗
PubMed1995

Enkephalin in the caudal PAG of rat: an immunocytochemical electron microscopic study.

Enkephalins are opioid peptides which elicit an analgesic effect when injected into the periaqueductal gray matter and in particular into its caudal part. In this study we wanted to investigate the fine structure of the neurons and of the synaptic circuits involved in the enkephalin action in rats using immunocytochemical pre-embedding methods. The labelled neurons show a small-medium sized soma, with a large nucleus, an absence of an extensive granular endoplasmic reticulum and few synaptic contacts. The synapses on enkephalin dendrites are often multiple, unlabelled and show both symmetrical and asymmetrical junctions. Enkephalin axon terminals make synaptic contacts on dendrites, usually unlabelled; contacts between enkephalin elements were occasionally seen. The enkephalin synapses show a symmetrical type of junction. These data give morphological support to the physiological findings, in particular to those suggesting an inhibitory effect of enkephalin on periaqueductal gray matter cells through a post-synaptic process. The findings are discussed with respect to pain modulation taking into consideration the enkephalin synaptic complex in intrinsic circuits and the possible ending of enkephalin axons on the projective neurons of the periaqueductal gray matter.

Animals↗
PubMed1995

Fine structure of the interstitial nucleus of Cajal of the cat.

The interstitial nucleus of Cajal (INC) is a mesencephalic nucleus considered to be an important premotor centre for eliciting vertical and rotatory eye and head movements. An ultrastructural analysis was carried out on the cat INC to elucidate the structure of the neurons and neuropil and, in particular, to examine the organisation of the synaptic relationships. The neuronal population is formed by a substratum of small and medium-sized neurons and by a limited number of larger neurons scattered throughout the nucleus. The small and medium-sized neurons display ultrastructural features similar to those shown by the cells of the central reticular formation. The larger neurons differ from those of the rest of the INC both in dimensions of their somata and in certain cytological characteristics (e.g. a well developed rough endoplasmic reticulum). Synaptic boutons are scarce at the level of the nerve somata and very abundant in the neuropil, thus indicating the latter as the main target field for the afferent inputs to the INC. Again the larger neurons are exceptions as their cell surface is extensively invested with axon endings. It is suggested that the larger neurons should be considered as a distinct cell population within the nucleus. On the basis of a morphometric analysis carried out on the synapses it is possible that in the INC, at the level of the somatic synapses, a mainly inhibitory role may be exerted, whereas in the neuropil it is possible that there is also excitatory control and modulation.

Animals↗
PubMed1995

[111In-DTPA-D-Phe]-octreotide scintigraphy in functioning and non-functioning pituitary adenomas.

Scintigraphy with [111In-DTPA-D-Phe]-octreotide is a recently developed technique for imaging somatostatin receptors in many neuroendocrine tumors. A good correlation between high [111In-DTPA-D-Phe]-octreotide uptake and the response to octreotide therapy has been proved in TSH- and GH-secreting pituitary adenomas, while few and conflicting scintigraphic data on somatostatin receptors in non-functioning tumors have been reported in the literature. The present study presents the results obtained with [111In-DTPA-D-Phe]-octreotide scintigraphy in thirteen patients with GH-secreting pituitary adenoma, four patients with inappropriate TSH-secretion and twelve patients with non-functioning pituitary adenoma. Twelve out of the 13 patients with GH-secreting pituitary adenomas had a positive scan; moreover, in 5/6 patients with a GH-secreting microadenoma (tumor size range 5-8 mm) a positive scan was found. Two TSH-secreting macroadenomas had a positive scan while a negative scan was obtained for a TSH-secreting pituitary microadenoma and in a patient with non-neoplastic, inappropriate secretion of TSH. Finally, only 2/12 patients with non-functioning pituitary adenoma showed a positive scan. In conclusion, [111In-DTPA-D-Phe]-octreotide scintigraphy is a useful tool to confirm the presence of somatostatin receptors in selected patients with GH- and TSH-secreting pituitary adenoma. The role of [111In-DTPA-D-Phe]-octreotide scintigraphy in non-functioning pituitary tumors remains to be established, but it could be useful for octreotide treatment in patients who refuse surgery or who are poor surgical candidates.

Adenoma↗
PubMed1994

Mechanism of S100 protein-dependent inhibition of glial fibrillary acidic protein (GFAP) polymerization.

S100 protein, a subfamily of Ca(2+)-binding proteins of the EF-hand type, was recently shown to bind to and to inhibit the polymerization of the glial fibrillary acidic protein (GFAP), the intermediate filament component of astroglial cells, in the presence of micromolar levels of Ca2+ (J. Biol. Chem. 268, 12669-12674). By a sedimentation assay and viscometry we show here that S100 protein interferes with the very early steps of GFAP polymerization (nucleation) and with the GFAP polymer growth, thereby retarding the onset of GFAP assembly, reducing the rate and the extent of GFAP assembly, and increasing the critical concentration of GFAP assembly. Moreover, S100 protein disassembles preformed glial filaments. All the above effects can be explained by sequestration of soluble GFAP by S100 protein, as also indicated by the stoichiometry of S100 protein binding to GFAP and of S100 protein effects on GFAP assembly. Our data suggest that S100 protein might serve the function of avoiding excess GFAP polymerization and might participate in remodeling of glial filaments following elevation of the intracellular free Ca2+ concentration. Also, our data lend support to the notion that intermediate filaments are dynamic cytoskeleton structures that assemble and disassemble, and to the existence of cytoplasmic factors implicated in the regulation of the state of assembly of intermediate filaments.

Animals↗