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Biomedical subjects

G Ferrari

Publications and source records attributed to G Ferrari.

At least 73 records · Page 4Linked to original sources

[The immediate and long-term efficacy of electrical cardioversion in atrial fibrillation].

With the aim to identify short- and long-term features predictive of successful electric cardioversion in stable atrial fibrillation, 186 consecutive patients submitted to electric cardioversion were reviewed. The following parameters were considered: age, atrial fibrillation duration, previous atrial fibrillation episodes, echocardiographic left atrial diameter, pre-treatment and prophylaxis with amiodarone. The patients were divided in 3 groups: Group I included 97 patients with mitral valve disease or mitral prosthesis, Group II included 27 patients with lone atrial fibrillation and Group III included 62 patients with different heart and extracardiac diseases. The electric cardioversion restored sinus rhythm in 155 patients (83%). The failure of the electric cardioversion was related only to a longer atrial fibrillation duration and to pre-treatment with amiodarone. Moreover, the failure of the electric cardioversion was more frequent in Group II patients (with lone atrial fibrillation) than in Group I patients (mitral disease or prosthesis; p < 0.005). Only for Group I patients failure of the cardioversion was related to a larger left atrium diameter (p < 0.05). Eighty-nine (57%) of the 155 patients converted to sinus rhythm were followed for at least 1 year. At 1 year sinus rhythm persisted in 57 patients (64%), and prophylaxis with amiodarone was the only predictor of sinus rhythm persistence (p < 0.05). Out of 68 patients with a 3 year follow-up, 29% still showed sinus rhythm after a single cardioversion and 37% after 2 or more cardioversions; after 5 years, out of 58 patients, those showing sinus rhythm were 6 (10.3%) and 9 (16%) respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Analysis of the factors influencing bicarbonate balance during acetate-free biofiltration.

In acetate-free biofiltration (AFB), the physical separation between the base losses and the gains could facilitate the modeling of intradialytic bicarbonate (HCO3) balance. In order to verify this hypothesis, we analyzed in a multicenter study, 126 AFB sessions in which differing parameters were evaluated (dialysis time, blood flow, ultrafiltration, infused HCO3, pre- and post-dialytic HCO3, hematocrit and body wt). Statistical analysis performed with multiple linear regression showed that the post-dialysis HCO3 was significantly dependent (F = 21.68, d.f. 5.95, P < 0.001) directly on the amount of infused HCO3, the level of pre-dialysis HCO3 and the final body weight, and inversely on the dialysis time and the blood flow. HCO3 values predicted by the statistical model correlated well with the observed ones (r = 0.788, P < 0.0001) with a mean absolute difference of 2.138 mEq/liter. This modeling approach allowed us to predict, with a computer-aided procedure, the quantities of HCO3 to be infused to obtain a desired and personalized acidosis correction.

Acetates

[Pulmonary toxicity due to amiodarone].

Two patients with coronary heart disease and previous myocardial infarction, treated with amiodarone for severe ventricular arrhythmias, developed pulmonary toxicity. The first developed pulmonary complications after 1 year of therapy at the maintenance dose of 300 mg/day, and the second after 4 months at 200 mg/day and 3 weeks at 400 mg/day. In the first patient, whose chest X-ray mainly showed interstitial infiltrates which resolved within more than 2 months after drug withdrawal, steroid therapy was administered. In the second patient, whose chest X-ray showed a pattern of pulmonary edema, the symptoms and signs resolved more rapidly after drug withdrawal and without steroid therapy. We suggest 2 distinct types of pulmonary toxicity in our patients. After withdrawal of amiodarone in the second patient the management of refractory ventricular arrhythmias was troublesome.

Aged

Gangliosides rescue neuronal cells from death after trophic factor deprivation.

Serum-free cultures of PC 12 cells have been used as a model system for studying neuronal death occurring after neurotrophic factor deprivation. In this system, NGF rescues cells from death and prevents apoptotic DNA fragmentation. We report here that GM1 also promotes long-term survival of naive and NGF-pretreated PC 12 cells in serum-free medium and prevents internucleosomal cleavage of PC 12 cell DNA. In contrast to NGF, GM1 does not promote neurite outgrowth or somatic hypertrophy. The survival effects of GM1 are concentration dependent, with maximal activity at 30-50 microM. Optimal promotion of survival is obtained with multiple additions of GM1. Asialo-GM1 and sialic acid do not mimic these actions, indicating a requirement for the intact GM1 molecule. Prevention of serum-free PC 12 cell death is also obtained with di-, tri-, and tetrasialogangliosides. The ganglioside effects on survival and DNA fragmentation appear to be independent of macromolecular synthesis. GM1 is also effective under conditions in which cellular protein kinase C activity is downregulated by preexposure to high concentration of 12-O-tetradecanoylphorbol-13-acetate. Furthermore, GM1 promotes long-term survival of cultured rat sympathetic neurons after withdrawal of NGF. These findings complement prior observations that gangliosides protect cerebellar granule neurons from neurotoxicity caused by exposure to excitatory amino acids and extend the actions of gangliosides to rescue of neuronal cells deprived of neurotrophic factor support.

Animals

Transfer of the ADA gene into human ADA-deficient T lymphocytes reconstitutes specific immune functions.

Peripheral blood lymphocytes obtained from a patient affected by adenosine deaminase (ADA) deficiency and severe combined immunodeficiency were infected with a retroviral vector containing two copies of a human ADA minigene, and injected into bg/nu/xid (BNX) immunodeficient mice. Six to 10 weeks after injection, human T cells were cloned from the spleens of recipient animals and analyzed for proliferative potential, T-cell surface markers, expression of ADA activity, integration of retroviral sequences, T-cell receptor (TCR) beta gene rearrangement, and specificity of antigen recognition. Efficient gene transfer and expression restored proliferative potential in vitro and long-term survival in vivo. All clonable human T lymphocytes obtained from the spleen of recipient animals had high levels of vector-derived ADA enzyme activity and showed predominantly the CD4+ phenotype. Retroviral integrations and TCR-beta gene rearrangements demonstrated the presence of a variety of different clones in the spleens of recipient mice. Furthermore, the combined analyses of vector integration and TCR rearrangement provided evidence that a circulating progenitor cell was transduced by the retroviral vector, giving rise to different and functional TCRs. Evaluation of antigen-specificity demonstrated both alloreactive and foreign antigen specific immune responses. These results suggest that restoration of enzyme activity in human ADA-deficient peripheral blood T cells by retroviral-mediated ADA gene transfer allows in vivo survival and reconstitution of specific immune functions. Therefore, retroviral vector-mediated gene transfer into circulating mononuclear cells could be successful not only in maintaining the metabolic homeostasis, but also for the development of a functional immune repertoire. This is a fundamental prerequisite for the usage of genetically engineered peripheral blood lymphocytes for somatic cell gene therapy of ADA deficiency.

Adenosine Deaminase

Age-related thiamin transport by small intestinal microvillous vesicles of rat.

The effect of aging on the intestinal transport of thiamin was studied using small intestinal microvillous vesicles prepared from groups of rats aged 1, 2, 6, 12 and 24 months, respectively. The vesicles (enrichment 14.6-17.8-fold) were incubated with 0.125 to 12.5 microM tritiated thiamin and the radioactivity taken up was measured radiometrically after rapid filtration. The time course and cumulative uptake curves of thiamin and the inhibiting potency of the thiamin structural analogs pyrithiamin, amprolium and oxythiamin on the saturable component of thiamin transport were determined. The vesicle diameter was measured by using a computerized morphometric procedure, and found to be decreased in aged rats. The Km and Jmax values of the saturable component of transport increased with increasing age, the difference with younger groups being statistically significant at 24 and 12 months. The inhibitory potencies of pyrithiamin and amprolium gradually decreased with increasing age, while oxythiamin was devoid of significant inhibitory activity. Passive permeability coefficients decreased with increasing age, reaching their lowest value at 24 months. These results show that aging is associated with intrinsic alterations of the enterocytic plasma membrane resulting in a decrease of the affinity for thiamin, associated with a faster rate of the saturable component of thiamin transport, and with a significant depression of the non-saturable component.

Aging

Gangliosides prevent the inhibition by K-252a of NGF responses in PC12 cells.

K-252a, a general kinase inhibitor, selectively blocks the actions of nerve growth factor (NGF) in PC12 cells. Since gangliosides have been reported to modulate neuronal cell responsiveness to NGF and to regulate several protein kinases, the ability of these compounds to reverse the inhibition by K-252a was tested. Parameters at both short- and long-term times following treatment of PC12 cells with NGF were analyzed which are known to be either transcription-dependent or -independent events. Gangliosides were found to completely prevent the inhibition by K-252a of NGF-induced neurite regeneration and c-fos induction, and partially also that of protein kinase N activation. The ganglioside protective effects were concentration-dependent and required the intact molecule. These findings raise the possibility that gangliosides might affect a specific pathway of NGF responses sensitive to inhibition by K-252a.

Animals

Octreotide administration in the treatment of pancreatic fistulae after pancreas transplantation.

Among the surgical complications of pancreas transplantation are pancreatic fistulae, which arise rather frequently. Suppression of exocrine secretion with polymers has succeeded in reducing the rate of this complication. Nevertheless, in some instances, pancreatic fistulas may occur. Thirty pancreas transplantations were performed in 27 diabetic patients. In 5 cases a pancreatic fistula occurred and was drained after the insertion of a catheter for the collection of secretions. A serous liquid was collected with a high concentration of amylases (61604 +/- 19562 IU/24 h). Fistula output was 280 +/- 87 ml/24 h. Patients were treated with octreotide, administered subcutaneously in a dose of 300-750 micrograms/day. In all patients a progressive reduction in fistula output was observed after a mean of 16 + 2 days. Fistula flow rate dropped to 24 +/- 10 ml/24 h--a reduction of 95% +/- 5% and drainage was subsequently stopped. Sonographic follow-up did not show recurrence of peripancreatic collections in these patients. All patients were insulin-independent up to 12-44 months after surgery.

Adult

A modular numerical model of the cardiovascular system for studying and training in the field of cardiovascular physiopathology.

A modular numerical model of the cardiovascular system has been developed to reproduce the most important circulatory phenomena in terms of pressure and volume relationships. It is an easy tool to use, designed to be used with a friendly approach on any IBM or compatible personal computer: it offers a wide selection of graphical and numerical outputs and can be rearranged easily for a particular experiment. A set of subroutines related to different circulatory phenomena has been developed; they can be assembled easily together and communicate with each other by two variables. A full description of the existing subroutines is presented in this paper with three different application examples resulting from the rearrangement of the existing software modules: the first concerns the behaviour of the natural ventricle model itself and can be regarded as a ventricle stand-alone characterization test in terms of preload and afterload sensitivities, the second is related to the use of a pneumatic ventricle instead of the model of the natural ventricle, and the third is a full model of the cardiocirculatory system.

Cardiology

Chemoimmunotherapy for prophylaxis of recurrence in superficial bladder cancer: interferon-alpha 2b versus interferon-alpha 2b with epirubicin.

Eighty-five patients who had undergone transurethral resection (TUR) of superficial bladder cancer were randomized to one of two treatments. Patients in Group 1 received a 10-month course of intravesical therapy with interferon (IFN)-alpha 2b (50 MU dose), commencing 21 days after TUR once a week for 8 weeks, then once every 15 days for 4 months and then finally once a month for 4 months. Patients in Group 2 received epirubicin (80 mg) intravesically 0, 24 and 48 h after TUR, and then 21 days after TUR received IFN-alpha 2b as for Group 1. The results confirmed the efficacy of immunoprophylaxis with IFN-alpha 2b, and early treatment with epirubicin tended to further reduce the percentage of relapses and extended the disease-free interval.

Antineoplastic Combined Chemotherapy Protocols

In vivo genetic variability of the human immunodeficiency virus type 2 V3 region.

The principal neutralizing epitope of the human immunodeficiency virus type 1 (HIV-1) lies between two invariant cysteines in the third variable region (V3) of the viral envelope (gp120), and its amino acid sequence varies among different HIV-1 isolates. HIV-2 carries an analogous amino acid sequence between two cysteines of the V3 regions, but its functional similarity with the HIV-1 principal neutralizing epitope is uncertain. We studied the degree of genetic variation of the HIV-2 V3 region in fresh blood samples from 12 HIV-2-seropositive individuals from Guinea-Bissau. Polymerase chain reaction was used to amplify viral fragments of 465 bp containing the V3 region from cellular DNA. Nucleotide sequence analysis of the entire envelope fragment from each patient revealed that the degree of variation among field isolates of HIV-2 is comparable to that observed in the analogous region of HIV-1. Most of the HIV-2 isolates studied were highly related, suggesting the existence of a limited number of different viral strains in the cohort studied. Thus, the HIV-2 and HIV-1 V3 regions vary to a similar degree and may also have analogous functions.

Amino Acid Sequence

Epidemiology of myasthenia gravis in the province of Trento (northern Italy).

The epidemiology of myasthenia gravis (MG) was studied in the province of Trento (northern Italy) among 444,879 inhabitants. On prevalence day (December 31, 1990) the crude rate was 82.9 per million population: 113 for females and 50.7 for males. The incidence rate was 7.4 per million per year: 10.8 for females and 4.6 for males. Over the same observation period (1981-1990), we calculated a death rate of 1.12 per million population per year. MG predominates in females. Nevertheless, we observed some differences related to age and to presence of thymoma, and our data supports the recognition of three types of MG: (1) predominating in females with a peak frequency at about 20-29 years; (2) affecting both males and females, with a frequency increasing with age, and (3) associated with thymoma.

Adolescent

Lack of feedback inhibition of insulin secretion in denervated human pancreas.

In this study, pancreas transplantation is used as a clinical model of pancreas denervation in humans. To assess the role of innervation on the feedback autoinhibition of insulin secretion, we studied four groups of subjects--group 1: 16 patients with combined pancreas and kidney transplantation (plasma glucose = 5.1 mM, HbA1c = 6.4%, creatinine = 86 mM); group 2: 8 patients with chronic uveitis on the same immunosuppressive therapy as transplanted patients (12 mg/day prednisone, 5 mg.kg-1.day-1 CsA); group 3: 4 uremic, nondiabetic patients in chronic hemodialysis; group 4: 7 normal, nondiabetic control subjects. The following means were used to study the groups: 1) a two-step hyperinsulinemic euglycemic clamp (insulin infusion rate = 1 mU and 5 mU.kg-1.min-1); and 2) a 0.3 mU.kg-1.min-1 hypoglycemic clamp (steady-state plasma glucose = 3.1 mM). Basal plasma-free IRI (84 +/- 6, 42 +/- 12, 72 +/- 12, and 30 +/- 6 pM in groups 1, 2, 3, and 4, respectively), basal C-peptide (0.79 +/- 0.05, 0.66 +/- 0.05, 3.04 +/- 0.20, and 0.59 +/- 0.06 nM in groups 1, 2, 3, and 4, respectively), and glucagon (105 +/- 13, 69 +/- 4, 171 +/- 10, and 71 +/- 5 pg/ml in groups 1, 2, 3, and 4, respectively) were increased in groups 1 and 3 with respect to groups 2 and 4 (P < 0.01). During euglycemic hyperinsulinemia, plasma C-peptide decreased by 45, 20, and 44% in groups 2, 3, and 4, respectively, but showed no significant change from the basal in patients with transplanted pancreases.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Hydroxybutyric Acid

[Ultrasound and color Doppler in the diagnosis of vasculogenic impotence].

Echo-color-doppler is a non invasive diagnostic technique which can provide data about arterial and venous vascular circle of the penis with greater precision than Doppler CW. In the tumescent phase after a PGE1 injection the systolic velocity (SV) reaches a rate higher than 25 cm/sec and the diastolic velocity (DV) higher than 2 cm/sec, resistance index (RI) > to 0.70 with evident colour marked from 1 to 3 KHz. In erection arterial flow decrease and SV is lower than 25 cm/sec with DV lower than 2 cm/sec or with negative values; RI < to 0.70 or negative. The data are confirmed by clinical investigation and traditional diagnostic exams in normal and pathological patients. Echo-color-doppler reduces invasive exams and acquires a primary position on the diagnostic scale of impotence.

Erectile Dysfunction

Effects of heparan-sulphate administration on clotting parameters and serum thromboxane B2 levels in cholesterol fed rabbits.

We evaluated the effects of heparan-sulphate administration on clotting times, thromboelastographic parameters and serum thromboxane B2 levels in hypercholesterolemic rabbits with aortic atherosclerotic lesions (sudanophilic areas). 24 New Zealand male rabbits were divided into three groups of 8 animals each. Group A and B were fed a rabbit chow diet containing 0.7% of cholesterol whereas Group C was fed a standard rabbit diet without cholesterol. Group A was treated by subcutaneous route with 6 mg/kg/day of heparan sulphate. At the beginning of the study and after 3 and 6 months of treatment, serum cholesterol and thromboxane B2 levels were tested. Furthermore, at the end of the experiment, we evaluated plasma fibrinogen, aPTT, PT and TT values. The administration of heparan-sulphate in cholesterol fed rabbits produced: a reduction of plasma fibrinogen levels, without modifying aPTT and TT; a protective effect vs the lengthening in PT values, likely induced by cholesterol rich diet; a reduction of plasma thrombophilic activities and of aortic atheromasic involvement induced by dietetic cholesterol intake. However, increased serum thromboxane B2 levels, likely through a proaggregant activity were observed. We suggest that heparan-sulphate administration, in cholesterol fed rabbits, has a favourable effect on clotting parameters, while contrasting effects were found on platelet activity.

Animals