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Biomedical subjects

S Pittalis

Publications and source records attributed to S Pittalis.

9 recordsLinked to original sources
PubMed1992

Rapid isolation of glucose-6-phosphate dehydrogenase from human erythrocytes by combined affinity and anion-exchange chromatography for biochemical characterization of variants.

A new method is presented for the purification of human glucose-6-phosphate dehydrogenase (G6PD) using affinity chromatography with 2'5'-ADP-Sepharose 4B followed by automated ion-exchange chromatography with DEAE 5PW. This rapid method allows a high recovery of enzyme activity from even a small amount of blood; the yield is about 90% after the first purification step and 70% at the end of the procedure. There is an excellent reproducibility of the kinetic parameters and optimal biochemical characterization of G6PD is achieved even for variants associated with severe enzyme deficiency (e.g. G6PD Mediterranean).

Chromatography, Affinity↗
PubMed1992

Modulation of macrophage response to interleukin-2 immunotherapy by interleukin-3 in cancer patients.

It has been observed that neopterin, a specific marker of macrophage activation, increases during cancer immunotherapy with IL-2, and this effect is mediated by interferons produced by IL-2-stimulated lymphocytes. Moreover, our previous studies have shown that neopterin rise during IL-2 immunotherapy is associated with an enhanced release of soluble IL-2 receptor (SIL-2R), which may suppress IL-2-dependent immune functions. This finding would suggest that neopterin increase may be related to the generation of suppressive events, which occur during IL-2 immunotherapy. On the basis of the documented modulatory effect of IL-3 on macrophage functions, we have evaluated the influence of IL-3 on neopterin secretion during IL-2 immunotherapy. The study was performed in advanced lung cancer patients. We have investigated 9 immunotherapeutic courses consisting of IL-2 (6M IU/day s.c. for 5 days/week for 3 weeks) plus IL-3 (1 microgram/(kg x day) i.v. for 14 days, starting 7 days before IL-2). The results were compared to those found during 18 courses with IL-2 alone. Mean neopterin levels increased significantly during IL-2 alone, but not in response to IL-3 plus IL-2. SIL-2R rise was significantly higher during IL-2 than during IL-3 plus IL-2. Mean numbers of NK cells and activated lymphocytes increased significantly in both groups of patients, but were significantly lower at the end of the treatment in patients receiving IL-2 alone than in those treated with IL-3 plus IL-2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1992

Enhanced secretion of tumour necrosis factor in patients with myocardial infarction.

OBJECTIVES: Recent evidence suggests that leukocyte infiltration of myocardial tissue may extend the area of necrosis during the acute phase of myocardial infarction. Since the activation of leukocytes depends on the action of cytokines, mainly tumour necrosis factor (TNF), we evaluated TNF secretion during myocardial infarction. METHODS: The study included 12 patients with acute myocardial infarction as diagnosed on the basis of enzymatic and ECG criteria. Patients were admitted within 3 hours from onset of chest pain. Serum levels of TNF were measured by immunoradiometric assay on venous blood samples collected at time 0, and at 6, 12 and 18 hours and 1, 2, 4 and 7 days following myocardial infarction. Plasma levels of atrial natriuretic peptide-alpha (ANP) were also measured on the same samples. RESULTS: Mean TNF levels significantly increased during the myocardial infarction, with a peak within the first 24 hours (p < 0.01). They remained significantly elevated until day 4 (p < 0.05). The rise in TNF was positively correlated with creatinine kinase levels. ANP was also significantly increased with a delayed peak after that of TNF (p < 0.01). CONCLUSION: Even though limited to a small number of cases, this study shows that acute myocardial infarction is associated with increased TNF secretion. Because of its capacity of stimulating leukocyte infiltration in myocardial tissue, the increased levels of TNF might potentially have a negative prognostic significance.

Aged↗
PubMed1991

Decrease in cholesterol levels during the immunotherapy of cancer with interleukin-2.

IL-2, in addition to its immunomodulating and antitumour properties, induces important systemic actions, including cardiovascular, neuroendocrine and metabolic effects. The present study was carried out to evaluate IL-2 effects on cholesterol metabolism. The study included 14 advanced cancer patients (renal carcinoma: ten; colon carcinoma: four), who received IL-2 subcutaneously at a dose of 1.8 x 10(6) IU ml-2 twice daily for 5 days/week for 6 weeks. Venous blood samples were collected 7 days before, on days 0, 3, 7, 14, 21, 42 of IL-2 therapy, and on days 14 and 28 of the rest-period. IL-2 induced a rapid and evident decrease in cholesterol levels, with a normalisation of its concentrations within 7 days in 10/10 hypercholesterolemic patients. The lowest mean levels of cholesterol were reached within the first 2 weeks; after that they still slowly increased. LDL-/HDL-cholesterol ratio was significantly reduced by IL-2 therapy. Cholesterol fall was associated with a marked increase in conjugated biliary acid levels. Finally, triglyceride values increased during IL-2 therapy, but not in a significant manner. These results, by showing that IL-2 exerts an evident and very rapid cholesterol-lowering activity, would represent a further demonstration of the physiological importance of cytokines in the control of cholesterol metabolism.

Adenocarcinoma↗
PubMed1991

[Cardioangioimmunology: the immune implications in the principle cardiovascular pathologies].

At present, it is known that the immune system acts through the release of protein factors, so-called cytokines. In addition to their immunomodulating and endocrinometabolic effects, cytokines have appeared to be able to have an influence on the cardiovascular system by inducing important haemodynamic changes. Cytokines cause hypotension, particularly IL-2 and TNF, due at least in part to a production of nitric oxide by endothelial cells. Cytokines, such as IL-1, IL-6 and TNF, stimulate myocardial infiltration by activating leukocytes and inducing the release of cytotoxic factors during myocardial infarction; that would extend the area of necrosis. Finally, cytokines would be involved in the pathogenesis of the atherosclerosis, and cholesterol metabolism itself would be under a cytokine control. On these bases, it is possible to suggest in the near future the elaboration of new therapeutic strategies and prognostic indications, according to the bioimmunological response of patients with cardiovascular diseases.

Arteriosclerosis↗
PubMed1989

Muscle glucose-6-phosphate dehydrogenase deficiency.

Muscle glucose-6-phosphate dehydrogenase (G6PD) deficiency is described in four clinically heterogeneous patients: an athlete who developed myoglobinuria after physical exercise; a 7-year-old, mildly mentally retarded boy, who had episodes of dark urine and high creatine kinase; and two brothers of Sardinian origin, the elder showing moderate exercise intolerance. Histochemical and biochemical studies showed a lack of G6PD activity in muscle biopsy specimens as well as in erythrocytes. G6PD characterization in erythrocytes classified these mutant enzymes as Mediterranean variant in all the patients. The deficiency was confirmed in the patients' myotubes and skin fibroblasts, where residual activity was present. Electrophoretic studies in tissue culture extracts showed that the residual muscle enzyme migrated as a single electrophoretic band like normal human muscle G6PD.

Adolescent↗
PubMed1989

Different polymorphic variants of glucose-6-phosphate dehydrogenase (G6PD) in Italy.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is common in Italy and recent biochemical and kinetic studies have demonstrated the presence of polymorphic variants associated with severe or mild enzyme deficiency. We performed a biochemical characterization of G6PD in a large number of Italian G6PD deficient men in an attempt to identify the most reliable biochemical indices for discriminating polymorphic G6PD variants and to define their distribution throughout the country. Three polymorphic G6PD variants, respectively named Mediterranean, Cagliari and Sassari, were identified. The elution profile on DEAE-Sephadex column chromatography, substrate analogue utilization and the Michaelis constant for G6P were the most significant parameters to discriminate polymorphic variants among the variants with activity levels lower than 0.8 IU/g Hb. The distribution of the polymorphic variants, in relation to the origin of the subjects studied, differs throughout the country.

Chromatography, Ion Exchange↗
PubMedDate not supplied

Tumor necrosis factor in solid tumors: increased blood levels in the metastatic disease.

TNF, a cytokine produced by macrophages, is able either to exert an antitumor activity, or to determine severe clinical complications, such as cachexia and septic shock. Increased blood levels of TNF have been described in cancer patients. The present study was performed to better define TNF secretion in patients with solid tumors. The study included 48 cancer patients (lung cancer: 22; colon cancer: 11; breast cancer: 10; renal cancer: 5), and among them 27 showed distant organ metastases. TNF serum levels were measured by IRMA method. The control group comprised 40 healthy subjects. TNF levels were also evaluated in relation to those of SIL-2R, whose increase seems to be associated with an unfavorable prognosis in cancer. High levels of TNF were seen in 27/48 (56%) patients. Mean levels of TNF were significantly higher in cancer patients than in controls. Moreover, within the cancer group, TNF mean values were significantly higher in metastatic patients than in those without metastases; the highest levels were observed in patients with visceral lesions as dominant metastasis sites. Finally, patients with high TNF concentrations showed significantly higher mean levels of SIL-2R than those with normal values. This study shows that the neoplastic metastatic disease is associated with an exaggerated TNF secretion.

Adult↗