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Biomedical subjects

G Ferrari

Publications and source records attributed to G Ferrari.

At least 235 records · Page 13Linked to original sources
PubMed1991

IL-1 beta-induced expression of PDGF-AA isoform in rabbit articular chondrocytes is modulated by TGF-beta 1.

Interleukin 1 beta (IL-1 beta) and platelet-derived growth factor (PDGF) induced proliferation in many cell types. Both peptides are released by activated macrophages and other cells in response to injury and are thought to play a crucial role in a number of pathological processes. We found that IL-1 beta stimulates proliferation of rabbit articular chondrocytes and induces synthesis and release of PDGF into their culture medium. This effect, which is time- and dose-dependent (0.05-5 ng/ml), is restricted to PDGF-AA, one of the three PDGF isoforms; IL-1 beta effect on PDGF is inhibited by actinomycin D and alpha-amanitin, suggesting a transcriptional regulation of PDGF-A chain. IL-1 beta stimulates PDGF-AA synthesis also in the presence of indomethacin, a prostaglandin synthesis inhibitor. Transforming growth factor beta 1 (TGF-beta 1), a dimeric polypeptide which displays multiple biological activities, inhibits in a dose-dependent manner (1-10 ng/ml) PDGF-AA production induced by IL-1 beta. In a binding assay, TGF-beta 1 induces 45% decrease in specific binding sites for 125I-IL-1 beta, with no change in affinity.

Animals↗
PubMed1991

Rat NGF receptor is recognized by the tumor-associated antigen monoclonal antibody 217c.

The expression of the epitope recognized by the tumor-associated antigen monoclonal antibody 217c increased on cultured rat Schwann cells with time. The same phenomenon has previously been reported for the rat nerve growth factor (NGF) receptor by using monoclonal antibody 192-IgG. The distribution of 217c antibody immunoreactivity closely paralleled that observed for NGF receptors on NGF-primed pheochromocytoma (PC12) cells in culture and a number of central neurons in vivo. Immunoprecipitation of affinity-labeled NGF receptors was used to examine whether these two antibodies shared common or unique antigens. Both the quantitative data and the electrophoretic mobility of the immunoprecipitated 125I-NGF/receptor complex indicate that the antigen recognized by the 217c mAb monoclonal antibody is, in fact, the NGF receptor. Furthermore, binding studies indicated that 192-IgG and 217c recognize different epitopes on the same molecule. The characterization of the 217c antibody should provide a valuable new tool in the study of NGF receptors.

Adrenal Gland Neoplasms↗
PubMed1991

Down-regulation of SPARC/osteonectin/BM-40 expression in methylcholanthrene-induced fibrosarcomas and in Kirsten-MSV transformed fibroblasts.

SPARC (secreted protein acid and rich in cysteine), also known as osteonectin or BM-40, is a glycoprotein associated with the extracellular matrix of bone as well as with many soft tissues that produce extracellular matrix, including matrix-producing tumours. Northern and slot-blot analyses were used to study SPARC expression in tumours induced in vivo by methylcholanthrene (MCA) and in transformed cells induced in vitro by Kirsten-MSV and SV-40 infection. MCA-induced tumours expressed SPARC mRNA at quantitatively different levels. Fibroblasts transformed in vitro by Kirsten-MSV, and, to a lesser extent, by SV-40, showed reduced levels of SPARC mRNA expression compared with normal fibroblasts. Run-on assay indicated that transcription of SPARC was lower in the Kirsten-MSV transformed cells than in the normal parental fibroblast culture. However, SPARC mRNA in the transformed culture was as stable as that in normal culture. The difference, therefore, between levels of SPARC mRNA in transformed and normal culture was mainly due to different rates of transcription. Cloned cell lines derived from the Kirsten-MSV transformed culture also showed heterogeneous expression of SPARC: two lines had high and two had low expression of the gene. The level of mRNA correlated with that of the protein secreted. The SPARC expression might contribute to the malignant phenotype.

Animals↗
PubMed1991

The effect of ethanol and other alcohols on morphometric parameters of rat small intestinal microvillous vesicles.

We have assessed the morphometric parameters of rat small intestinal microvillous vesicles, prepared by a Ca(2+)-precipitation method, from normal, long term ethanol-treated and pair-fed saccharose -treated control rats. The vesicles from normal rats were also directly exposed to ethyl, butyl and benzyl alcohols, respectively. Computerized morphometric analysis was carried out on electron micrographs of microvillous vesicles. The size of vesicles from ethanol-treated rats, as well as control rats, was significantly reduced as compared to normals. Direct exposure of vesicles to alcohols significantly increased vesicle dimensions, with a potency order reflecting the liposolubility of alcohols. These data support the hypothesis that variations in vesicle diameter may be ascribed at least in part to the fluidizing effect of alcohols. Thiamin transport by the vesicles has been measured in the presence of ethanol. The time course of thiamin uptake was not affected by ethanol.

Alcoholism↗
PubMed1991

Effect of magnetic fluids on the efficiency of an electromagnetic actuator prototype.

An electromagnetic actuator to substitute ventricular function presents some advantages compared with different energy converters. The drastic reduction of the moving parts leads to greater reliability and an accurate control system can be set up. Its major limitations concern weight, heat dissipation and, finally, the overall pump efficiency which is usually rather low. We investigated the possibility of using magnetic fluids in an electromagnetic actuator. Limitations intrinsic to the magnetic fluids prevent their being used as pumping elements but they can be useful to increase the pump efficiency by reducing losses in the magnetic circuit. A remarkable increase in pump efficiency was attained. It is necessary to point out that in designing the electromagnetic actuator the focus was on the pump efficiency with and without the magnetic fluids more than on its performance.

Electromagnetic Phenomena↗
PubMed1990

[Impact of a surveillance and prevention program on the incidence of wound infections in general surgery. A prospective study].

A prospective study on wound infections incidence was performed using a computer archive program. Data of 7000 patients submitted to surgical procedures from 1980 to 1988 were evaluated regarding a surveillance and a prevention program that was performed at 1984 (short term prophylaxis in contaminated and any clean-contaminated procedures; skin washing before the operation with a soapy solution of povidone iodine; regular report of all data about wound infection incidence to staff). Results were evaluated in four classes and regarding nutritional status. The reduction of wound infection incidence was statistically significant (1.8% vs 5.4%; chi square 63.70, p less than 0.001) and an important reduction was recorded in the malnourished patients (3.0% vs 15.4%; chi square 36.91, p less than 0.001).

Humans↗
PubMed1990

[Ofloxacin in prophylactic therapy of oral infections].

86 patients (46 females, 40 males; mean age 37 years) were divided into 2 groups: one group of 40 patients with acute infectious odontostomatitis, and another group of 46 patients going to have their oral cavity surgically operated. The first group was treated with 300 mg oral tablets of ofloxacin 12 hourly for 5 days, the second group with the same posology for 3 days, for prophylactic purposes. 54 cases (24 in the first group and 30 in the second one) had Fans drugs integrating antibiotic therapy. At the end of the antibiotic treatment the first group showed a complete abatement of symptoms in 16 cases, a significant improvement in 19 cases, and better clinical conditions in 5 cases. The second group, examined again 4 and 7 days after surgical intervention, showed the prophylactic antibiotic treatment beneficial in 30 cases after 4 days, and in 14 cases after 7 days; for 2 cases it was necessary to replace the antibiotic drug by other. Side effects in both groups (14 cases) were slight and did not cause any treatment interruption. Given these results and the good tolerability of the drug, we conclude that orally administered ofloxacin is a valid alternative to the parenteral drug for the treatment of infectious odontostomatitis and for prophylaxis after oral surgery.

Administration, Oral↗
PubMed1990

T-cell receptor genes in tassel-eared squirrels (Sciurus aberti). I. Genetic polymorphism and divergence in the Abert and Kaibab subspecies.

The role of environmental factors in the evolution and maintenance of diversity of antigen receptor gene families which participate in the immune response in mammals is inadequately understood. In order to elucidate the impact of these factors, we have undertaken the analysis of these gene families in the tassel-eared squirrel (Sciurus aberti) which has been separated into discrete subspecies by geographic barriers and whose food resources can be quantitated for estimating environmental quality. In this communication we describe the initial analysis of the complexity and polymorphism of sequences related to T-cell receptor (Tcr) alpha and beta chain genes in two subspecies, Sciurus aberti aberti (Abert) and Sciurus aberti kaibabensis (Kaibab) which have identical habitats and are separated by the Grand Canyon in Arizona, USA. Genomic blot analysis of 60 Abert and 62 Kaibab individuals collected over a 3-year period was performed with mouse Tcrb and Tcra cDNA probes. Sequences homologous to Tcrb-C, Tcrb-J1, and Tcrb-J2 genes were observed in all individuals from both subspecies; although Tcrb-J1 fragments were monomorphic. Tcrb-C and Tcrb-J2 fragments were polymorphic with both species- and subspecies-specific sequences. A single, monomorphic Tcra-C fragment was observed in addition to multiple Tcra-V fragments homologous to the mouse Tcra-V1 subfamily. Abert samples exhibited greater numbers of Tcra-V1 fragments as well as greater polymorphism than Kaibab samples. Heterozygosity estimates of Tcrb-C and Tcra-V1 sequences were determined for annually collected samples and compared with the yearly estimates of availability of hypogeous fungi, one of the major diet items of tassel-eared squirrels. In the Kaibab annual collections, Tcra-V1 heterozygosity declined with the decline in food resource, whereas heterozygosity of Tcrb-C sequences was inversely related to food resource. Similarly, a reduction in food resource for Abert squirrels in 1985 coincided with an increase in Tcrb-C heterozygosity in the same year. These results suggest that the diversity of gene families which participate in the immune response in mammals may be affected by environmental factors.

Animals↗
PubMed1990

Reduction of insulin resistance by combined kidney-pancreas transplantation in type 1 (insulin-dependent) diabetic patients.

To evaluate the effect of combined kidney and pancreas transplantation on insulin action and glucose metabolism, 15 Type 1 (insulin-dependent) diabetic patients who were undergoing combined kidney-pancreas transplantation were studied before transplantation by means of the euglycaemic hyperinsulinaemic clamp technique combined with 3-3H-glucose infusion and indirect calorimetry. Nine of the original 15 patients were studied again after four months and six after 12 months, successful combined kidney-pancreas transplantation with the same experimental protocol. Nine volunteers formed the group of normal subjects. Combined kidney-pancreas transplantation normalised hepatic glucose production and reduced peripheral insulin resistance in Type 1 diabetic uraemic patients, despite chronic immunosuppressive therapy. To further evaluate the hypothesis that residual insulin resistance was due to chronic steroid therapy. 11 additional subjects with chronic uveitis (six of whom were treated with only prednisone, and five treated only with cyclosporin) underwent the same protocol demonstrating a normal hepatic glucose production. The insulin-stimulated peripheral glucose uptake was reduced in the prednisone-treated group, but normal in cyclosporin-treated subjects. Four additional diabetic patients with a kidney transplant were also studied. They showed a peripheral insulin sensitivity intermediate between diabetic uraemic patients and patients after combined transplant. We conclude that short-term (one year) combined kidney-pancreas transplantation improves glucose metabolism by restoring normal rates of hepatic glucose production and reducing peripheral insulin resistance; chronic steroid therapy is the major determinant of residual reduced insulin action. Both kidney and pancreas substitution play a role in reducing peripheral insulin resistance.

Adult↗
PubMed1990

Thiamin transport by human erythrocytes and ghosts.

Thiamin transport in human erythrocytes and resealed pink ghosts was evaluated by incubating both preparations at 37 or 20 degrees C in the presence of [3H]-thiamin of high specific activity. The rate of uptake was consistently higher in erythrocytes than in ghosts. In both preparations, the time course of uptake was independent from the presence of Na+ and did not reach equilibrium after 60 min incubation. At concentrations below 0.5 microM and at 37 degrees C, thiamin was taken up predominantly by a saturable mechanism in both erythrocytes and ghosts. Apparent kinetic constants were: for erythrocytes, Km = 0.12, 0.11 and 0.10 microM and Jmax = 0.01, 0.02 and 0.03 pmol.microliter-1 intracellular water after 3, 15, and 30 min incubation times, respectively; for ghosts, Km = 0.16 and 0.51 microM and Jmax = 0.01 and 0.04 pmol.microliter-1 intracellular water after 15 and 30 min incubation times, respectively. At 20 degrees C, the saturable component disappeared in both preparations. Erythrocyte thiamin transport was not influenced by the presence of D-glucose or metabolic inhibitors. In both preparations, thiamin transport was inhibited competitively by unlabeled thiamin, pyrithiamin, amprolium and, to a lesser extent, oxythiamin, the inhibiting effect being always more marked in erythrocytes than in ghosts. Only approximately 20% of the thiamin taken up by erythrocytes was protein- (probably membrane-) bound. A similar proportion was esterified to thiamin pyrophosphate. Separate experiments using valinomycin and SCN- showed that the transport of thiamin, which is a cation at pH 7.4, is unaffected by changes in membrane potential in both preparations.

Biological Transport↗
PubMed1990

Schwann cells promote the survival of rat retinal ganglion cells after optic nerve section.

Schwann cells (SCs) are known to play an important role for the regeneration of mammalian peripheral nerves. Their effect is likely due to the production of neuronotrophic and/or supportive factors. Here we study the effect of intraocular transplant of SCs on the survival of rat retinal ganglion cells (RGCs) after the intracranial section of the optic nerve. SCs were injected intraocularly in adult hooded rats. Surviving RGCs were retrogradely labeled with horseradish peroxidase applied to the proximal stump of the optic nerve. Results show that intraocular transplants of SCs promote the survival of a large number of RGCs for periods as long as 9 and 14 weeks after optic nerve section. In experimental retinae, surviving RGCs were 2- to 8-fold more numerous than in controls. This finding suggests that SCs are the source of factors that promote the survival of RGCs. Nerve growth factor is produced by SCs, and the intraocular injection of nerve growth factor has been previously shown to promote RGC survival. The rescuing effect of SCs on RGCs is greater than that obtained by intraocular injection of nerve growth factor. This greater effect may be due to the action of other neurotrophic factors produced by SCs or by transplanted SCs producing NGF in a sustained fashion.

Animals↗
PubMed1990

Prophylactic mezlocillin-netilmicin combination in permanent transvenous cardiac pacemaker implantation: a single-center, prospective, randomized study.

A prospective, randomized study was carried out in order to assess the efficacy and safety of the mezlocillin-netilmicin combination in the prophylaxis of first permanent transvenous cardiac pacemaker implantation. Five hundred and fifty-two consecutive patients were randomly administered either 2 g mezlocillin and 200 mg netilmicin both as an i.v. bolus before implantation or 2g mezlocillin before and then 6 and 12 hours after surgery and 200 mg netilmicin before and then 12 hours after implantation. No adverse events were seen. Neither pocket nor electrode infections were observed in the 457 subjects still alive (mean follow-up: 29.2 months) or in patients who died after 1 year of follow-up (mean follow-up: 20.1 months) or before this time (mean follow-up: 4.7 months). The serum and pocket concentrations of mezlocillin and netilmicin at the end of surgery were found to be adequate to cover microorganisms that most often cause infections, including methicillin-resistant staphylococci.

Bacterial Infections↗
PubMed1990

A new system for follow-up patients with permanent pacemakers.

The use of a new computerized system for coordinating technical and clinical data and especially for filing the parameters found during out-patient checkups enables us to rationally carry out follow-up of approximately 900 patients with pacemakers in our electrostimulation laboratory without wasting time or data. The system is composed of a personal Olivetti M240 computer, with a 20 Bbyte and 640 Kram hard disk, an analog-digital interface and a personalized data base for coordinating and filing the parameters found. The type of pacemaker implanted (monocameral, dual chamber or rate responsive) is of no consequence to the system that is based on the acquisition of the surface electrocardiogram. A comparison of the filed data on printouts or graphs allows us to note every type of misfunction or anomaly in the stimulation system in real time.

Computer Systems↗
PubMed1990

Acetate-free biofiltration: hemodiafiltration with base-free dialysate.

Bicarbonate dialysis has several clinical advantages compared to conventional acetate hemodialysis. However, the use of bicarbonate in the dialysate requires complicated hardware with considerable maintenance and servicing. We have developed a new dialysis technique, a modification of hemodiafiltration, called acetate-free biofiltration (AFBF), with no base replacement agents in the dialysate and with the infusion of bicarbonate solution in postdilution fluid. This study consisted of two parts, an acute phase (8 dialysis patients) and a chronic phase (4 patients) lasting up to 12 months. In the first phase we evaluated the effects of different amounts of infused bicarbonate (from 751 to 1,002 mEq per session) on acid-base balance. The best correction of uremic acidosis was obtained with the infusion of 900-1,000 HCO3 mEq during a 3-hour AFBF. There was a significant (p less than 0.0001) positive correlation between infused and gained bicarbonate. In the chronic part, 880-910 HCO3 mEq was infused per session and there was an increase in mean pretreatment plasma bicarbonate from 18.1 +/- 2.2 upon starting to 22.8 +/- 0.4 mEq/l by the end of the 12-month period. A very low incidence of intradialytic hypotension and stable serum chemistries were achieved with this technique as compared with standard hemodialysis despite a reduction of 3 h in weekly treatment time. AFBF is an easy-to-use, safe alternative to bicarbonate dialysis thanks to the absence of pyrogen reactions and comparatively low-cost maintenance.

Acid-Base Imbalance↗