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Biomedical subjects

G Valentini

Publications and source records attributed to G Valentini.

At least 127 records · Page 7Linked to original sources
PubMed1989

Lymphocyte proliferative response to mitogenic monoclonal antibodies in systemic sclerosis. Evidence for unresponsiveness to murine monoclonal antibodies of IgG1 isotype.

Proliferative response of peripheral blood mononuclear cells to phitohemoagglutinin and anti-CD3 mitogenic monoclonal antibodies (MoAbs) of the IgG2a (OKT3) and IgG1 (PanT2, CLB T3/4.1) isotypes was studied in 39 patients with systemic sclerosis (SSc) and in 82 control subjects. The effect of IL-2 on this response was also investigated. No difference in the response to PHA and to IgG2a anti-CD3 MoAb OKT3 was seen between scleroderma patients and controls. Both the patient and control groups contained responders and non-responders to IgG1 anti-CD3 MoAbs. The percentage of non-responders was significantly higher in scleroderma patients than in controls. When purified lymphocytes from non-responder scleroderma patients were cultured with monocytes from control responders, proliferative response to IgG1 MoAbs was restored. Our results show that monocytes from patients with systemic sclerosis bear a defect leading to IgG1 unresponsiveness by T lymphocytes.

Adolescent↗
PubMed1989

L-carnitine addition to dialysis fluid. A therapeutic alternative for hemodialysis patients.

L-Carnitine has been reported to have beneficial effects in the reduction of serum triglycerides and increases high-density lipoprotein cholesterol in hemodialysis patients. The published reports are, however, equivocal. Paradoxical increases in serum triglycerides following intravenous administration of L-carnitine have been observed. It has been suggested that the paradoxical rise in triglycerides may result from the high doses used and intravenous administration, both of which may cause abnormally high tissue concentrations. In the present study 22 hemodialysis patients were selected. All patients had been treated intravenously with 2 g of L-carnitine administered at the end of dialysis for a minimum of 12 months. Treatment with L-carnitine was then discontinued during a 4-month washout period. The patients were then divided into two equal subgroups and placed on L-carnitine therapy (1 g i.v.) at the end of dialysis for 1 month. Thereafter, L-carnitine was added to the dialysate (2 g in group 1, 4 g in group 2) for 3 months. Serum and muscle carnitine levels were determined throughout the study as were lipid parameters, serum chemistry, and hematology. Muscle biopsies obtained at baseline revealed supranormal levels of carnitine which decreased to normal levels following the 4-month washout period. When therapy with L-carnitine was resumed, intravenous administration or in dialysate, the muscle carnitine levels remained within the normal range. Similarly, serum carnitine was markedly elevated at baseline and decreased to normal during the washout period. When L-carnitine was added to the dialysate, total carnitine was observed to significantly increase in the group receiving 4 g.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Beta-2-microglobulin is a reliable tumor marker in chronic lymphocytic leukemia.

Serum beta 2-microglobulin (beta 2M) was measured in 22 patients with B chronic lymphocytic leukemia (CLL) and in 15 healthy age-matched control subjects. The patients were allocated in stages in accordance with the Rai and Binet systems. The beta 2M mean value in the CLL group was significantly higher than in the control group. There was a positive correlation between beta 2M and the clinical stage in both staging systems. The mean serum levels of beta 2M in stages A, B and C of Binet's system showed statistical differences while in stage A they did not differ from those found in the control group. No correlation was demonstrated between beta 2M and the peripheral lymphocyte concentration. A slight correlation was found between beta 2M and the degree of bone marrow lymphocyte infiltration, whereas a stronger relationship was observed when the type of infiltration (non-diffuse versus diffuse) was considered. Patients with bulky disease had mean beta 2M values much higher than the others.

Aged↗
PubMed1989

Primary structure of three peptides at the catalytic and allosteric sites of the fructose-1,6-bisphosphate-activated pyruvate kinase from Escherichia coli.

Three peptides containing 6-pyridoxyllysine have been isolated from the tryptic digest of the allosteric fructose-1,6-bisphosphate-dependent pyruvate kinase from Escherichia coli, which had been almost completely inactivated with pyridoxal 5'-phosphate. The labelled peptides have been sequenced. The comparison of their sequences with the primary structure of the cat muscle pyruvate kinase allowed to state that peptide I fits the region spanning residues 423-438 (53% identity), peptide II corresponds to residues 442-457 (44% identity) and peptide III encompasses residues 342-368 (70% identity). These findings are discussed in connection with our previous results on the involvement of the three peptides in the catalytic and regulatory properties of the enzyme (Valentini, G., Speranza, M.L., Iadarola, P., Ferri, G. & Malcovati, M. (1988) Biol. Chem. Hoppe-Seyler 369, 1219-1226) and in connection with their location in the three-dimensional structure of the cat muscle pyruvate kinase (Muirhead, H., Clayden, D.A., Lorimer, C.G., Fothergill-Gilmore, L.A., Schiltz, E. & Schmitt, W. (1986) EMBO J. 5, 475-481).

Amino Acid Sequence↗
PubMed1989

[Acute effects of propionyl-L-carnitine on anomalies of parietal kinetics of the left ventricle induced by atrial pacing in patients with ischemic heart disease. A bidimensional echocardiographic study].

This double-blind randomized placebo (PL) controlled study was undertaken to evaluate, by 2D echo transesophageal atrial pacing (TAP), the effects of acute iv administration of a new compound propionyl-L-carnitine (PLC) on atrial pacing (AP) induced left ventricular wall motion abnormalities. Twelve male patients with coronary artery disease and normal regional motion at rest, after a preliminary 2D echo-TAP, on the eight and thirteenth day of trial were subjected to 2D echo-TAP 30 min after iv administration of 15 mg/Kg PLC or PL. For analysis, the left ventricle was divided into 11 segments. A wall motion score (WMS), evaluated at 130 b/min and at 150 b/min, was derived by adding together the scores assigned to each segment. Wall motion was graded +2 (normokinetic), +1 (hypokinetic), 0 (akinetic), -1 (dyskinetic). Left ventricular ejection fraction (EF) was evaluated at rest and at 150 b/min. Statistical analysis of the results was performed using a 2-way analysis of variance. The WMS at 130 b/min improved significantly after PLC vs PL from 18.66 +/- 2.46 to 19.50 +/- 2.77 (p less than 0.02). The WMS at 150 b/min improved significantly after PLC vs PL from 16.00 +/- 2.95 to 16.91 +/- 3.47 (p less than 0.01). The EF at rest was not significantly unchanged after PLC. The EF at 150 b/min was significantly different after PLC vs PL, from 53.6 +/- 7.36 to 55.6 +/- 6.45 (p less than 0.05). The blood pressure and the double product at rest and at 150 b/min were not unchanged after PLC.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Reactivity of the fructose 1,6-bisphosphate-activated pyruvate kinase from Escherichia coli with pyridoxal 5'-phosphate.

The allosteric fructose 1,6-bisphosphate-activated pyruvate kinase from Escherichia coli was modified with pyridoxal 5'-phosphate in the presence and in the absence of phosphoenolpyruvate, fructose 1,6-bisphosphate, MgADP and MgATP. In all cases a time-dependent inactivation was observed, but the rate and the extent of inactivation varied according to the conditions used. The kinetic properties of the partially inactivated enzyme were differently modified by addition of substrates and effectors to the modification mixture, the parameters mostly affected being those concerning fructose 1,6-bisphosphate. Tryptic peptides obtained from fully inactivated pyruvate kinase in the different conditions have been separated. In all conditions three main 6-pyridoxyllysine-containing peptides were present, the amounts of which showed significant differences in the presence of fructose 1,6-bisphosphate and MgADP. The function of the labelled peptides and the evidence supporting the physical existence of different conformational states are discussed. The main conclusion concerns the involvement of one of the above peptides in the binding of the allosteric effector fructose 1,6-bisphosphate.

Enzyme Activation↗
PubMed1987

Influence of fibronectin on the fibrillogenesis of type I and type III collagen.

The in vitro self-assembly of type I and type III calf skin collagen in the presence of fibronectin was studied turbidimetrically. Fibronectin delayed the fibrillogenesis of type III collagen but accelerated that of type I collagen. The effect of fibronectin was concentration-dependent. The lag phase was more altered than the growth phase in the presence of fibronectin while the final turbidity and the amount of fibrils formed were unmodified. Fibrils obtained in the presence of fibronectin all showed native banding pattern. Fibronectin bound partly to collagen fibrils; the amount of bound fibronectin was similar for the two types of collagen and tended to be constant at increasing fibronectin concentrations. It is suggested that the antithetic effect of fibronectin on type I and type III collagen fibrillogenesis may arise both from the different affinity of fibronectin to the two types of collagen and the different aggregation properties of each collagen type.

Animals↗
PubMed1987

Influence of testosterone therapy on clinical and immunological features of autoimmune diseases associated with Klinefelter's syndrome.

To examine the role of sex steroid hormones in the development of autoimmune diseases, we studied five patients with Klinefelter's syndrome associated with autoimmune disease, three of whom had Sjögren's syndrome (SS) and two of whom had systemic lupus erythematosus (SLE). Serum testosterone (T) and LH levels, antinuclear antibodies (ANA) and rheumatoid factor (RF) titers, erythrocyte sedimentation rate (ESR), hemolytic complement (CH50) levels, and peripheral T lymphocyte subsets (OKT3+, OKT4+, and OKT8+) were measured before treatment, after 60 days of placebo treatment, and after 60 days of oral T undecanoate (TU) treatment. Before treatment and after placebo, with respect to normal men, the patients had lower serum T and higher LH levels, lower percentages and absolute values of OKT3+ (total T lymphocytes) and OKT8+ (suppressor/cytotoxic T lymphocytes) cells, and, consequently, an increased OKT4/OKT8 ratio. Hemolytic complement (CH50) in serum was below normal in the two patients with SLE, while it was normal in the patients with SS. The ESR was above normal in all patients, and all had high titers of ANA and RF. After TU therapy, serum T levels increased and LH levels decreased, but not to normal. OKT3+ and OKT8+ cells and the OKT4/OKT8 ratio became normal, and RF and ANA titers decreased. The CH50 level did not change in the SS patients, while it increased to normal in the two patients with SLE. The ESR decreased in all patients during therapy. Furthermore, after TU therapy, both the SS and SLE patients had a clinical remission of their autoimmune disease. Our results indicate a therapeutic effect of T on autoimmune diseases in patients with hypogonadism and Klinefelter's syndrome.

Adult↗
PubMed1987

Ocular aspects in biotinidase deficiency. Clinical and genetic original studies.

There are two distinct forms of multiple carboxylase deficiency. A neonatal onset form is due to deficiency of holocarboxylase-synthetase. A later onset form in which neurological abnormalities are seen as well as those of the skin and hair is due to biotinidase deficiency. It is the purpose of this report to describe a patient with biotinidase deficiency who presents bilateral optic atrophy. The dosage of biotinidase enzyme in the patient's serum and in other members of his family confirms the autosomal recessive transmission of this condition.

Alopecia↗
PubMed1986

Anterior ischemic optic neuropathy in type I diabetes.

Anterior ischemic optic neuropathy (A.I.O.N.) may cause optic disc edema in type-I diabetes. A.I.O.N. affects diabetic patients of all ages. Such optic neuropathy is more likely to become bilateral in diabetics than in the non-diabetic subjects. A 41-year-old diabetic insulin-dependent woman presented A.I.O.N. in RE; 5 years later, the same affection occurred in LE. The clinical course was relatively benign in both eyes, with good functional restitution. The patient was treated by high doses of Sodium Salicylate and Sulfinpyrazone. The pathogenesis of optic disc edema in type-I diabetes is, according to Hayreh (1981), ischemia of different grade in the district of the posterior ciliary arteries: microangiopathy, rheological anomalies and atherosclerotic added lesions produce a variability of clinical pictures of increasing seriousness. Our case has an intermediate position in such a continuous spectrum. The VEP supported the diagnosia of A.I.O.N.

Adult↗
PubMed1986

Different antibody patterns and different prognoses in patients with scleroderma with various extent of skin sclerosis.

Ninety patients who fulfilled the ARA criteria for systemic sclerosis were divided into 6 groups on the basis of cutaneous areas of sclerosis. Anticentromere antibody (ACA) was found in 14 of 28 patients of the first 2 groups, the first group being pure sclerodactyly, and the second sclerodactyly plus minimal sclerotic lesions (eyelids, neck, armpits). In the other 4 groups (62 patients) in whom skin sclerosis was more diffuse, ACA was found in one case. Fluorescent antinuclear antibodies (FANA) with a diffusely grainy pattern, those with a nucleolar pattern and the anti-Scl-70 antibody were present in all 6 groups, but were significantly more frequent in the last 4 groups than in Groups 1 and 2. The cumulative survival rate as well as disease duration were found to be significantly longer in the first 2 groups designated "limited cutaneous systemic sclerosis," than in the 5th and 6th groups, i.e., patients in whom the trunk also was involved: "diffuse cutaneous systemic sclerosis." The cumulative survival rate and disease duration of patients with skin sclerosis of the face and limbs, but not of trunk, were not significantly different either from those of patients with limited cutaneous systemic sclerosis or from those of patients with diffuse cutaneous systemic sclerosis. Thus these patients show the same antibody pattern as diffuse cutaneous systemic sclerosis, but the prognosis not significantly different from the other 2 subsets. We suggest they constitute a distinct subset of systemic sclerosis for which we propose the name "intermediate cutaneous systemic sclerosis."

Adolescent↗