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D Giavarina

Publications and source records attributed to D Giavarina.

17 recordsLinked to original sources
PubMed1998

External Quality Assessment of stat test intralaboratory turnaround times. Pilot study from the Members of the Working Group for the Standardization and Promotion of Turnaround Time Control under the Auspices of the Comitato Italiano per la Standardizzazione dei Metodi Ematologici e di Laboratorio.

We describe procedures, results and prospects of a pilot program in External Quality Assessment (EQA) of the stat test intralaboratory turnaround times. Our goals are to promote quality by systematic monitoring and comparison of performances by laboratories, continuous investigation into the state of the art of the processes from receipt of sample to transmission of results and creation of a data base for standardization of measures and definition of consensus values for turnaround time. Of 30 laboratories invited to participate, 25 took part, agreeing to record times of arrival and transmission for all determinations of three analytes (blood hemoglobin, serum/plasma potassium and plasma prothrombin time) for seven consecutive days and to continue for one or more further periods of seven days as necessary if there were less than 300 determinations for each analyte. Within a preset time limit, data were sent by e-mail on an Excel file and we sent back two reports per analyte, showing: i) the graph for time vs. percentage of tests completed and several measures of turnaround time; ii) results of all laboratories in graph form, allowing each laboratory to identify only its own data. The high proportion of participating laboratories among those invited (83%) encourages us to implement the EQA program systematically, on a half-yearly basis, extending it to all laboratories wishing to participate in Italy or elsewhere in Europe.

Italy↗
PubMed1997

Estimating mean pulmonary wedge pressure in patients with chronic atrial fibrillation from transthoracic Doppler indexes of mitral and pulmonary venous flow velocity.

OBJECTIVES: We sought to obtain a noninvasive estimation of mean pulmonary wedge pressure (MPWP) in patients with chronic atrial fibrillation (AF). BACKGROUND: It has previously been demonstrated that MPWP can be reliably estimated from Doppler indexes of mitral and pulmonary venous flow (PVF) in patients with sinus rhythm. Doppler estimation of MPWP has not been validated in patients with AF. METHODS: MPWP was correlated with variables of mitral and pulmonary venous flow velocity as assessed by Doppler transthoracic echocardiography in 35 consecutive patients. The derived algorithm was prospectively tested in 23 additional patients. RESULTS: In all patients the mitral flow pattern showed only a diastolic forward component. A significant but relatively weak correlation (r = -0.50) was observed between MPWP and mitral deceleration time. In 12 (34%) of 35 patients, the pulmonary vein flow tracing demonstrated only a diastolic forward component; a diastolic and late systolic forward flow was noted in the remaining 23 patients (66%). A strong negative correlation was observed between MPWP and the normalized duration of the diastolic flow (r = -0.80) and its initial deceleration slope time (r = -0.91). Deceleration time > 220 ms predicted MPWP < or = 12 mm Hg with 100% sensitivity and 100% specificity. When estimating MPWP by using the equation MPWP = -94.261 PVF deceleration time -9.831 Interval QRS to onset of diastolic PVF -16.337 Duration of PVF + 44.261, the measured and predicted MPWP closely agreed with a mean difference of -0.85 mm Hg. The 95% confidence limits were 4.8 and -6.1 mm Hg. CONCLUSIONS: In patients with chronic AF, MPWP can be estimated from transthoracic Doppler study of PVF velocity signals.

Age Factors↗
PubMed1996

Serum paraoxonase activity is decreased in uremic patients.

Paraoxonase is a high-density lipoprotein (HDL)-associated enzyme capable of hydrolysing lipid peroxides. We measured the activity of serum paraoxonase together with serum concentrations of a variety of lipid constituents--total cholesterol, high-density lipoprotein (HDL) and low-density lipoprotein (LDL), cholesterol, triglycerides, apolipoproteins A-I and B--in 60 hemodialyzed (HD) patients. We found that the paraoxonase activity was significantly reduced in HD patients compared with 64 healthy controls (mean median and interquartile values: 93, 63, 87 IU/l in HD patients and 151, 120 and 135 IU/l in controls). In patients, the trimodal frequency of distribution of paraoxonase activity showed a shift toward lower levels. The effect of NaCl on enzyme activation was more pronounced in the patient group, as compared with controls, suggesting a higher frequency of the B allozyme (more responsive to NaCl) in this population. We suggest that altered HDL subfraction, present in HD patients, may be the main cause of the widespread depression of paraoxonase. Furthermore, the higher frequency of allozyme B among HD patients might increase the risk of coronary artery disease. In conclusion, paraoxonase activity may be an adjunctive index of altered lipoprotein metabolism with important repercussions on atherosclerosis.

Adolescent↗
PubMed1989

Monomeric calcitonin secretion in infants with congenital hypothyroidism.

We have determined CT levels in whole serum (iCT) and by an extraction method (exCT) in 25 infants affected by congenital hypothyroidism (CH)--11 athyreotic and 14 dysgenetic--at age 25 days, before the institution of therapy, and at age 2 years. In hypothyroid patients at age 25 days the iCT and exCT levels were similar to those found in controls of the same age. At age 2 years the iCT and exCT levels decreased in both groups of patients. However, whereas the levels of iCT in hypothyroids were similar to those found in controls of the same age, the levels of exCT were significantly lower in hypothyroids than in controls; moreover they were significantly lower in athyreotic than in dysgenetic patients. At this age, after calcium infusion, exCT levels significantly increased in dysgenetic but not in athyreotic patients. We hypothesize that CT deficiency in CH is due to increased degradation of human CT by the substitutive therapy, which, stimulating proteolytic enzymes, destroys the biologic activity of CT. An extraction procedure improves the sensitivity and specificity of the CT assay and it must be used when CT deficiency is suspected. In addition we suggest that the measurement of exCT levels after Ca infusion might be useful to distinguish dysgenetic from athyreotic patients.

Calcitonin↗
PubMed1988

Mineral metabolism in obese children.

Blood levels of glucose, insulin (IRI), Calcium (Ca), phosphorus (P), alkaline phosphatase (AP), osteocalcin (OC), parathyroid hormone (PTH), calcitonin (CT), 25-hydroxyvitamin D3 (25OHD3), 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) and urinary excretion of Ca (Ca/Cr), P (TmP/GFR), hydroxyproline (OH-P/Cr) and cyclic AMP (cAMP/GFR) were determined in 16 obese children, aged 8 to 11 years, on a diet rich in calories and carbohydrates and in 15 controls of the same age. Blood glucose, IRI, Ca, P, PTH and CT were also determined in both groups of subjects, during an oral glucose tolerance test (OGTT). In basal conditions glucose, IRI, AP, OC, PTH, CT and 1,25(OH)2D3 levels were significantly higher, and 25OHD3 levels lower, in obese children than in controls. Urinary Ca/Cr, TmP/GFR were lower in obese than in non obese children, while OH-P/Cr and cAMP/GFR were higher. Bone mineral content (BMC), measured by photon absorptiometry, and BMC/bone width ratio were lower in obese than in non obese children. During OGTT serum Ca and P decreased and serum PTH and CT increased less in obese than in non obese children. In obese children receiving a diet with high carbohydrate content, an alteration of mineral metabolism occurred, characterized by secondary increase of PTH and 1,25(OH)2D3. Ca decreased and PTH and CT increased less markedly during OGTT.

Alkaline Phosphatase↗
PubMedDate not supplied

The role of erythrocytes in the deperoxidative processes in people on hemodialysis.

The defenses against the production of free radicals and reactive oxygen species (ROS) are to be found in plasma (ascorbate, urate, alpha tocopherol) and in erythrocytes (superoxide dismutase or SOD; catalase or CAT; glutathione peroxidase or GPx). In chronic renal failure, an increased lipid peroxidation and a reduced antioxidant activity seem to be present, but previous reports are conflicting. To clarify the peroxidative status and the defense mechanisms taking place in patients on dialysis, in 30 patients on dialysis (15 men, 15 women) and in 20 control subjects (10 men, 10 women), the following parameters were measured: plasma 4-hydroxinonenal (4-HNE) and erythrocyte reduced glutathione (GSH), SOD, GPx, and glucose-6-phosphate dehydrogenase (G-6-PD). Patients on dialysis, in comparison with control subjects, had 1) increased levels of 4-HNE (p < 0.001); 2) a significant increase in erythrocyte-GSH (p < 0.05); and 3) significant decreases in erythrocyte-SOD (p < 0.001), erythrocyte-G-6-PD (p < 0.005), and the erythrocyte-SOD/GPx ratio (p < 0.001). The dialysis procedure induced a certain reduction in plasma 4-HNE, an increase in erythrocyte-SOD activity, and an important consumption of erythrocyte-GSH, while the erythrocyte-SOD/GPx ratio changed. The current study supports the view that 1) erythrocytes act as small detoxifying packets; 2) in chronic renal failure, the antioxidant system is largely inadequate; and 3) in patients on dialysis, the antioxidant mechanism of erythrocytes in scavenging ROS is effectively exerted during dialysis but remains largely inadequate, as signs of lipid peroxidation persist with time.

Aged↗
PubMedDate not supplied

Free radicals and oxidative stress challenge dialysis patients: effects of two different membranes.

Patients with end-stage renal disease (ESRD) who undergo hemodialysis manifest pronounced oxidative stress (OS), for the antioxidant system is inadequate to correct the imbalance between generation and scavenging of reactive oxygen species (ROS). To clarify the role of two different membranes on the OS, we measured plasma lipid peroxidation (LPO) and erythrocyte concentration of several antioxidant enzymes on 20 controls and 6 patients on bicarbonate dialysis (BHD). At 7 days intervals, 2 BHD sessions were done on the same 6 hemodialysis patients: the two BHD sessions were similar, except for the membrane used (cuprophan, first study; regenerated cellulose = Bioflux, second study, 7 days later). Before, during, and after each session (0', 30', 60', 120', end, 30' after BHD end), several blood samples were drawn. Lipid peroxidation and erythrocyte glutathione (GSH), superoxide dismutase (SOD), and catalase were spectrophotometrically determined (Bioxytech, France), but for erythrocyte glutathione peroxidase (Gpx) and G-6-PD, Gunzler's and Beutler's methods were used, respectively. Both membranes induce a significant decrease in LPO (p < 0.01) and an increase in erythrocyte SOD (p < 0.05). Bioflux shows some peculiar effects: a significant increase in erythrocyte GSH (p < 0.05) and erythrocyte catalase (p < 0.01) with a gradual increase of erythrocyte SOD and catalase/SOD ratio. Cuprophan, on the contrary, causes a sudden increase in erythrocyte SOD, while erythrocyte catalase decreases. These data support the view that Bioflux induces an OS lower than cuprophan because with the former, increased H2O2 production leads (thanks to catalase and GPx action) to water generation. With cuprophan, instead the reduced SOD/catalase ratio causes a greater H2O2 generation and a lower conversion to water.

Adult↗