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Biomedical subjects

C Meloni

Publications and source records attributed to C Meloni.

At least 73 records · Page 4Linked to original sources
PubMed1968

Ischaemic heart disease in middle-aged men. Prevalence comparisons in Europe.

The authors report the results of a collaborative study of the prevalence of ischaemic heart disease in 6 samples of middle-aged male clerical workers, drawn from 5 European countries and covering in all 4522 subjects. Detailed standardization of data-collection methods and of coding, analysis and tabulation was undertaken.Estimated prevalence rates for angina and history of possible infarction, based on the use of a standard questionnaire, showed significant variation between samples, but the validity of international comparisons of symptoms remains unproven. Prevalence rates for ischaemic-type ECG findings were high everywhere, and mostly showed no significant variation between the groups studied. Central coding of ECG findings proved essential to the making of unbiased comparisons. Neither the prevalence rates for symptoms nor those for ECG findings in these samples were recognizably correlated with the corresponding national mortality rates for ischaemic heart disease.Several possible risk factors were studied, but the only one found to be consistently associated with ischaemic heart disease was a raised blood pressure. Cigarette smoking was strongly associated with bronchitic symptoms and dyspnoea, but an association with heart disease was not demonstrated.

Blood Pressure↗
PubMedDate not supplied

Ultrasound in the diagnosis of gallbladder ascariasis.

Ascariasis is the most common helminthic infection, but the invasion of worms into the gallbladder is quite rare. This report illustrates the ultrasonographic findings in gallbladder ascariasis of a typical echogenic structure which exhibits nondirectional movements and contains a central anechoic tube, along the long axis of the gallbladder. The role of ultrasound as a diagnostic tool and in the follow-up treatment is stressed.

Animals↗
PubMedDate not supplied

Disappearance of oxidative damage to red blood cell membranes in uremic patients following renal transplant.

Hemodialysis patients display increased oxidative damage to red blood cell (RBC) membranes, characterized by elevated levels of malonyldialdehyde (MDA), a short chain aldehyde produced by the oxidation of the polyunsaturated fatty acids (PUFA) in the RBC membranes. This is the result of a metabolic blockage of the pentose-phosphate shunt in uremic patients, which causes reduced detoxification of highly oxidative free radicals. The oxidative damage induces increased RBC rigidity and decreased RBC deformability, therefore favoring hemolysis. The aim of this work was to determine if a functioning renal graft would restore normal erythrocyte metabolism, reducing the oxidative damage. To this end, we have determined RBC MDA concentrations in 20 hemodialysis (HD) patients (RBC MDA 18.22 +/- 4.36 micrograms/ml packed RBC), 20 renal transplant (T) patients with well functioning grafts (serum creatinine less than 2 mg%) (RBC MDA 1.2 +/- 0.4 micrograms/ml packed RBC) (T vs. HD P less than 0.005) and 20 healthy controls (HC) (RBC MDA 1.44 +/- 0.6 micrograms/ml packed RBC) (HC vs. HD P less than 0.005; HC vs. T NS). Our findings show that a well-functioning renal graft restores normal RBC metabolism and eliminates the oxidative damage induced by uremia.

Adolescent↗
PubMedDate not supplied

Plasmapheresis versus plasma perfusion in acute Guillain-Barré syndrome.

Guillain-Barré Syndrome (GBS) is an acute post infectious or disimmune illness that affects nerve roots and peripheral nerves. Multicenter studies have clearly shown that plasma exchange (PE) provides valuable amelioration of GBS. It was recently suggested that plasma perfusion (PP) on phenylalanine columns displays the same therapeutic effects of PE in neuroimmunologic disorders, without the infectious risks linked with plasma replacement. In this study, the authors compared the efficacy of PE versus that of PP in two groups of patients suffering from GBS by investigating the clinical outcomes and the electrophysiologic and cerebrospinal fluid findings. Of 22 patients suffering from GBS, 16 underwent seven sessions of PE in a mean time of 15 days (Group A). Six patients, showing the same clinical pattern, underwent three sessions of PP in a mean time of 10 days (Group B). Data reported in Group A show that PE: 1) stops the progressive worsening of the disease, 2) prevents the development of acute respiratory failure, 3) allows an early and significant clinical improvement with change in disability grade, and 4) improves motor conduction velocities and motor action potentials when recorded 45 days after the end of treatment. Data in Group B show that PP allows a slower and later improvement in disability grade, and electrophysiologic data recorded at the end of treatment was worse after 45 days. Finally, it may be concluded that PE has beneficial effects on GBS in terms of time of recovery, complication rate, and relapses. Plasma perfusion did not show the same results.

Acute Disease↗
PubMedDate not supplied

Oxidative damage to RBC membranes and pentose phosphate shunt activity in hemodialysis patients after suspension of erythropoietin treatment.

During follow-up of anemic hemodialysis patients (HDP) treated with recombinant human erythropoietin (rHuEpo), it was noticed that in five HDP, some time after suspension of rHuEpo, hemoglobin (Hb) levels remained at acceptable levels. A metabolic block of the pentose phosphate shunt (PPS) has been described in HDP, which leads to increased oxidative damage of red blood cell (RBC) membranes and increased susceptibility to hemolysis. The increased production of short-chain fatty aldehydes, including malonyldialdehyde (MDA), is an appropriate index of oxidative damage. This study aimed to verify whether the maintenance of acceptable levels of Hb was related to a change in RBC membrane oxidative damage and pentose phosphate shunt activity. In the five HDP in question who required rHuEpo (150 U/kg/week) for severe anemia (Hb = 7.48 +/- 0.95 g/dl), after a stable level of Hb > 10 g/dl was reached for at least 1 month, rHuEpo treatment was stopped. Hb levels remained adequate (Hb = 10.68 +/- 0.77 g/dl) after 14.6 +/- 7.64 months. The oxidative damage was evaluated by measuring RBC MDA (microgram/ml packed RBC) basal levels, and PPS activity by measuring MDA levels after incubation with ascorbate and cyanide (delta % RBC MDA production). Ten anemic HDP not treated with rHuEpo were used as controls (Hb = 8.12 +/- 1.32 g/dl). It was found that the maintenance of adequate levels of serum Hb after suspension of rHuEpo therapy is related to a decrease in RBC membrane oxidative damage (RBC MDA HDP = 2.40 +/- 0.41 vs. RBC MDA controls = 18.23 +/- 6.56; P < 0.005) in consequence of the normalization of pentose phosphate shunt activity.

Aged↗
PubMedDate not supplied

Acute renal failure occurring during intravenous desferrioxamine therapy: recovery after haemodialysis.

A patient with transfusion-dependent thalassemia was undergoing home intravenous desferrioxamine (DFX) treatment by means of a totally implanted system because of his poor compliance with the nightly subcutaneous therapy. Due to an accidental malfunctioning of the infusion pump, the patient was inadvertently administered a toxic dosage of the drug which caused renal insufficiency. Given the progressive deterioration of the symptoms and of the laboratory values, despite adequate medical treatment, a decision was made to introduce haemodialytical therapy in order to remove the drug and therapy reduce the nephrotoxicity. From the results obtained, haemodialysis can therefore be suggested as a useful therapy in rare cases of progressive acute renal failure caused by desferrioxamine.

Acute Kidney Injury↗
PubMedDate not supplied

Administration of GSH has no influence on the RBC membrane: oxidative damage to patients on hemodialysis.

In patients on hemodialysis, a metabolic block of the pentose phosphate shunt has been described that impairs the reduction of oxidized glutathione. The block results in lack of detoxication of the free hydroxyl radicals produced inside the red blood cell (RBC) and causes oxidative damage to the polyunsaturated fatty acids of the RBC membrane that results in formation of aldehydes. Malonyldialdehyde has been used as an index of the oxidative damage. In a study group of 13 patients on hemodialysis, the authors have tested whether administering reduced glutathione (GSH) at 1200 mg/day for 1 month could minimize oxidative damage to the RBC membranes and improve the hematologic parameters. Treatment with GSH was followed by significant improvement of hematocrit (P = 0.008), hemoglobin (P = 0.03), and RBC count (P = 0.0037); however, oxidative damage to the membranes was increased (P = 0.0004), which suggests that improvement of the hematologic parameters is not related to reduction of the oxidative damage. This is because oxidized glutathione, formed in the oxidative process, cannot be reduced back to GSH because of alteration of the pentose phosphate shunt.

Adult↗
PubMedDate not supplied

[Long-term clinical experience in post-dilution HFR].

PURPOSE: Hemodiafiltration reinfusion (HFR) is characterized by the use of regenerated ultrafiltrate as replacement fluid. We devised a new technique, post-dilution HFR, aimed at increasing the purification efficiency, treatment tolerability and at reducing inflammatory state. METHODS: We performed post-dilution HFR in six uremic patients during 18 months. Dialytic efficacy, filter blood rest and cytokine behavior were evaluated. RESULTS: Neither pyrogenic reactions nor other adverse phenomena were recorded. The tolerance to the treatment was excellent. We observed a high rate of urea extraction and optimal Kt/V values, a high extraction of beta2 microglobulin (beta2-m) and a reduction in blood rest; in addition, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) significantly decreased. CONCLUSIONS. The inversion of the standard HFR configuration allowed us to improve the removal of both urea and beta2-m, and the blood rest, with an optimal tolerability. Moreover, the reduction in cytokine levels could attenuate the uremic microinflammatory state.

Adult↗
PubMedDate not supplied

[Comparison between two different on-line dialytic techniques: Standard HFR vs post-dilutional HFR].

PURPOSE: Among hemodiafiltration (HFD) techniques, hemodiafiltration reinfusion (HFR) seems unable to achieve an optimal depurative efficacy. This study aimed to evaluate whether the HFR technique as suggested in its original configuration could be improved by devising a new technique (post-dilution HFR (PDHFR)) inverting the purification sequence to increase the purification efficiency of the entire system. METHODS: We performed standard HFR in six uremic patients during 6 months and, subsequently, during a further 6 months, PDHFR was performed. The dialytic efficacy of the two techniques and the filter blood rest were evaluated. In addition, we studied the behavior of cytokines during the inverted HFR sessions. RESULTS: We observed a significant increase in urea extraction and in Kt/V. An equally significant improvement was observed with regard to beta2-microglobulin (beta2-m) extraction and blood rest. Furthermore, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) significantly decreased after inverted HFR treatment. CONCLUSIONS: The inversion of the original configuration allowed us to improve the depurative efficacy of standard HFR, increasing the removal of both urea and beta2-m, and reducing the blood rest. Finally, it was notable that the reduction in cytokine levels could attenuate the uremic microinflammatory state.

Adult↗
PubMedDate not supplied

Vitamin E supplementation and oxidative status of peripheral blood mononuclear cells and lymphocyte subsets in hemodialysis patients.

Increased oxidative damage to cell membrane constituents causes profound changes in the membrane cytoarchitecture and modifications of the membrane physiological properties, e.g., the ability to respond to hormonal stimuli. In uremic patients receiving intermittent hemodialysis, a metabolic block of the phosphate pentose shunt has been described. This leads to insufficient detoxication of the hydroxyl radicals formed within the cells and therefore to increased oxidative damage to the polyunsaturated fatty acid constituents of the cell membranes. Vitamin E is known to reduce this oxidative damage and its harmful effects. We studied vitamin E (alpha-tocopherol acetate) administration in 10 chronically uremic patients receiving intermittent hemodialysis for positive effects on cell membrane-receptor response. The patients were studied before and after treatment for the extent of oxidative damage in peripheral mononuclear cells and for response to monoclonal antibodies to specific markers of T-lymphocyte subsets. After vitamin E treatment, oxidative damage decreased, and the membranes of peripheral mononuclear cells contained greater amounts of some unsaturated fatty acids. This is in agreement with a modification of the membrane phenotype markers of T-lymphocyte subsets and seems to confirm in vivo that changes in membrane structure first induced by increased oxidative damage due to the blockage of the phosphate pentose shunt can be reduced by the antioxidant action of vitamin E, which significantly influences the expression of membrane determinants.

Adult↗