PubMed Health⌕ Search

Biomedical subjects

M Pradella

Publications and source records attributed to M Pradella.

At least 19 recordsLinked to original sources
PubMed2004

Accuracy of semiquantitative immunoenzymatic methods in quantitation of anti-topoisomerase I (Scl-70) antibodies.

Reports of a possible correlation between anti-Scl-70 antibody concentration and clinical manifestations in systemic sclerosis patients have recently appeared in the scientific literature. The goal of our study was to evaluate, by means of a multicenter study, the analytical reliability of immunoassay systems in the quantitative measurement of Scl-70 antibodies. Three blind samples (H, M, L) at different anti-Scl-70 antibody concentrations, and a low concentration antibody serum (LPC) used as a common calibrator, were sent three times in a 6-month time span to 39 Italian clinical laboratories. Each laboratory was asked to calculate dosages following the enzyme-linked immunosorbent assay (ELISA) method they used and report the optical density values of each sample (ODs), of the cutoff serum provided by the manufacturer of the kit used (ODco) and of LPC (ODLPC). The overall analytical imprecision (between methods and between laboratories) of the three different determinations of the values respectively expressed in ODs, ODs/ODco and ODs/ODLPCratio was 47.1, 52.8 and 34.0% for sample H, 56.2, 47.4% and 34% for sample M and 84.6, 86.0 and 86.6% for sample L. The average intra-method analytical imprecision was, respectively, 20.7, 29.8 and 18.6% for sample H, 24.6, 26.5 and 19.3% for sample M, and 30.6, 28.1 and 20.2% for sample L. The commercial ELISA methods currently used to determine the presence of anti-Scl-70 autoantibodies show considerable differences in the quantitative determination. The best results for reproducibility analyses have been obtained when the values were expressed as a ratio between the ODs of the sample and of the common calibrator (ODs/ODLPC). Forward-looking clinical studies that can clarify the usefulness of quantitative determination of anti-Scl-70 antibodies in the monitoring of diffuse scleroderma patients can be performed only when standard serum with a known antibody concentration and calibration curves for quantitative ELISA measurements are made available.

Autoantibodies↗
PubMed2000

Sensitivity and specificity of immunological methods for the detection of anti-topoisomerase I (Scl70) autoantibodies: results of a multicenter study. The Italian Society of Laboratory Medicine Study Group on the Diagnosis of Autoimmune diseases.

BACKGROUND: The ability of immunometric methods to identify anti-topoisomerase I (Scl70) antibodies is controversial. We wished to quantify the performance of the currently available commercial systems for the assay of anti-topoisomerase I antibodies in a large multicenter study. METHODS: Fifty Italian clinical laboratories analyzed 36 serum samples: 27 from individuals with scleroderma/systemic sclerosis, and 9 from a control group. The scleroderma/systemic sclerosis samples were positive in our laboratories by both ELISA and immunoblot (IB), and the control samples were negative. The laboratories used 42 immunoenzymatic (ELISA), 21 IB, 3 counterimmunoelectrophoresis, and 2 dot-blot methods, produced by 23 different manufacturers. RESULTS: We obtained 2389 results. The ELISA methods showed 99.2% specificity and 97.2% sensitivity for detection of anti-Scl70 antibodies. For IB methods, specificity was 97.6% and sensitivity was 96.1%. The Western-blot method had poor analytical specificity (27% false positives for anti-extractable nuclear antigen antibodies other than anti-Scl70). CONCLUSIONS: Excluding Western blots, commercial ELISA and IB reagents as used in clinical laboratories have a sensitivity and a specificity >95% for determination of anti-Scl70 antibodies.

Autoantibodies↗
PubMed1999

[Detection of anti-ENA autoantibodies in patients with systemic connective tissue diseases. Analytical variability and diagnostic sensitivity of 4 methods].

This study was designed to assess the analytical sensitivity and rate of agreement between commercial methods and reagents, among the most used in Italy for the detection of autoantibodies to extractable nuclear antigens (ENA). Sixty-eight serum samples from patients with clinically diagnosed systemic rheumatic diseases were aliquoted and distributed to 4 hospital laboratories; three ELISA (Elias, Shield, Inova) and 1 immunoblot method (Euroimmun) were used. Overall agreement between the test reagents, for each anti-ENA specificity, was 69.1% for Ro/SSA, 83.3% for La/SSB, 70.6% for RNP, 73.5% for Sm, 91.1% for Jo1, and 82.3% for Scl70. Lack of specificity (i.e., false positive reactions) was the most important cause of low concordance. When the data were analysed according to the clinical diagnosis, total agreement and specificity improved. However, a significant difference in terms of sensitivity was observed in the SLE group (30 sera) for RNP (positivity ranged from 20% to 43%) and for Sm (from 7% to 37%), and in the Sjögren's syndrome group (13 sera) for anti-La/SSB (from 8% to 38%). Comparable data were obtained for anti-Ro/SSA (from 70% to 77%) both in the SLE and the Sjögren's syndrome group. Sensitivity of all 4 reagents was good in detecting anti-Scl70 autoantibodies in the 8 patients with diffuse systemic sclerosis, as well as anti-Jo1 autoantibody in the 5 polymyositis patients, with a 100% and a 95% agreement, respectively. These data suggest the need of a better standardization of commercial reagents and analytical procedures, and the opportunity that every laboratory should perform anti-ENA determination by at least two different methods, since none of the methods tested was completely reliable in detecting all anti-ENA autoantibody specificities.

Antibodies, Antinuclear↗
PubMed1998

Variability between methods to determine ANA, anti-dsDNA and anti-ENA autoantibodies: a collaborative study with the biomedical industry.

This study was performed by the Italian Society of Laboratory Medicine (SIMeL) in order to establish the variability between the different analytical systems currently used in clinical laboratories for the detection of autoantibodies diagnostic of systemic autoimmune disease. Sixteen industrial, and two university laboratories participated in this study which entailed the determination of anti-nuclear (ANA), anti-dsDNA and anti-ENA antibodies in 11 sera from patients with clinically diagnosed systemic rheumatic disease, using reagents produced by these companies and different methodologies (indirect immunofluorescence, immunoenzymatic assay, counterimmunolectrophoresis, immuno and western blotting). We found 93.5% agreement between the methods used for the detection of ANA, 85.2% for anti-dsDNA antibodies, and 86.9% for anti-ENA antibodies. Among the anti-ENA antibodies, regardless of the method used, detection percentages were excellent for anti-RNP and anti-SSB/La (100%), good for anti-SSA/Ro (93%), but unacceptable for the anti-Jo-1 (67%), anti-Scl70 and anti-Sm (47%) antibodies. This further stresses the need for rigorous standardisation of commercial reagents and analytical procedures, as well as the introduction of external quality assessment (EQA) programs, and a complete definition of operative protocols adjusted to the sensitivity and specificity of the various methods.

Antibodies, Antinuclear↗
PubMed1996

n-3 fatty acids do not enhance LDL susceptibility to oxidation in hypertriacylglycerolemic hemodialyzed subjects.

Recent data suggest that treatment with n-3 fatty acids could enhance the susceptibility of plasma low-density-lipoprotein (LDL) to oxidation. Twelve hypertriacylglycerolemic, hemodialyzed patients were treated with 2.5 g n-3 fatty acids/d for 2 mo. Treatment was then withdrawn for 2 mo (washout phase). Plasma total cholesterol and LDL cholesterol increased significantly (9% and 28%) and plasma triacylglycerols decreased significantly after the n-3 phase compared with baseline and washout values. LDL susceptibility to oxidation was tested by oxidation of LDL particles with 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH). No significant changes were observed for the lag phase and the peroxidation rate. The vitamin E content of LDL also did not change significantly. The results thus suggest that a daily dosage of 2.5 g n-3 fatty acids does not enhance LDL susceptibility to oxidation, while retaining its hypotriacylglycerolemic effect.

Amidines↗
PubMed1996

Reticulocytes in haematological disorders.

The increased precision of flow cytometric techniques permits the recognition of small differences even in the low or normal range of the reticulocyte count. Moreover, measurement of the RNA content of reticulocytes makes possible the identification of the youngest highly fluorescent macroreticulocytes (HFR) prematurely delivered from bone marrow in conditions of increased erythropoietic stimulation. The aim of this study was the definition, using the dedicated flow cytometers Sysmex R-1000 or R-3000 (Toa Medical Electronics Ltd, Kobe, Japan), of reticulocyte absolute number and HFR percentage in patients with haematological disorders prior to any treatment. Analysis of 54 healthy subjects and 100 untreated patients with five types of haematological disease is presented. In haemolytic anaemias (15 cases) both the reticulocyte count and HFR were greatly increased and the reticulocyte count was inversely correlated with Hb level, as in the reference population. In polycythaemia vera (20 cases) reticulocytes were moderately increased and directly correlated with Hb. In dyserythropoietic syndromes (20 cases) reticulocytes were low and HFR moderately increased; HFR showed an inverse correlation with Hb. In acute myeloid leukaemia (30 cases) reticulocytes were low and HFR increased; reticulocytes correlated with both HFR and Hb. In acute lymphoid leukaemia (15 cases), while the reticulocyte count did not differ from the reference group, the HFR was increased. These results provide reference values for the evaluation of reticulocyte counts and HFR in haematological diseases. From a physiopathological standpoint, they suggest that in anaemic patients the reticulocyte count directly reflects effective bone marrow erythrocyte production, while the proportion of circulating HFR more closely reflects the intensity of erythropoietic stimulation.

Adult↗
PubMed1996

Assessing erythropoiesis and the effect of erythropoietin therapy in renal disease by reticulocyte counting.

Renal disease is characterized by failure of erythropoietin (Epo) production and low bone marrow sensitivity to Epo. The reticulocyte count is the best laboratory marker of erythropoiesis available, but reticulocytes have not been extensively studied in renal disease. Cluster analysis suggests that in non-haemodialysed renal patients the anaemia is associated with uraemia while the reticulocyte number and immature subclasses are correlated with the ineffective erythropoietic component of the anaemia. This emphasizes the importance of treating the renal disease in patients with the anaemia of end-stage renal failure. Human recombinant Epo therapy has been demonstrated to be effective in correcting anaemia in most cases of chronic renal insufficiency. In renal patients the reticulocyte count should only be monitored by automated methods to assure reliability at low counts.

Anemia↗
PubMed1995

Quantitative cytochemistry of human leukocyte elastase compared with plasma elastase and acute phase proteins in inflammatory diseases.

Plasma levels of human leukocyte elastase, a serine proteinase stored in the azurophilic granules of polymorphonuclear granulocytes, increase in the early stages of several inflammatory diseases. We studied the intracellular enzyme activity by cytochemical quantitative image analysis and the amount of elastase released in plasma by an automatic immunoactivation immunoassay method in 66 patients with inflammatory diseases and in a control group. The patients were divided into two groups with infective disease (severe and moderate) and one group with non-infective inflammation. Intracellular activity and plasmatic levels of elastase were also compared with other inflammatory markers, i.e. erythrocyte sedimentation rate, C-reactive protein, alpha 1-antitrypsin, haptoglobin, alpha 1-acid glycoprotein and fibrinogen. Our studies suggest that plasma and leukocyte elastase are correlated both with etiology and with the severity of the inflammation.

Acute-Phase Proteins↗
PubMed1995

A quantitative method to measure alkaline phosphatase activities in individual leukocytes by image analysis.

Leucocyte alkaline phosphatase (L-ALP) is well known as leukemia marker, but recent results suggest its usefulness for the diagnosis of several diseases. The aim of this study was to develop a quantitative method to measure alkaline phosphatase activities in individual leukocytes by image analysis. We studied the reaction rate of L-ALP in human polymorphonuclear leucocytes by a microscope attached to a TV camera and a computerized image analyzer. The optical density (OD) measured was standardized by grey filters with known absorbance. We measured IOD for individual cells after a set incubation time by end-point measurements. Studies of kinetic parameters of L-ALP were performed by single-point measurements in the linear phase of the reaction and at increasing substrate concentrations. Cellular IOD increased proportionally with incubation time up to 10 min. The mean KM(mM) and Vmax(delta IOD/min) values were 0.70 +/- 0.11 and 1.76 +/- 0.2 (mean +/- SE, n = 5) respectively. Our findings are comparable to previous results using a polyvynil alcohol method in microphotometry analysis. The image analysis of cellular L-ALP activity appears a valuable tool for quantitative studies.

Alkaline Phosphatase↗
PubMed1995

Neutrophil NADPH oxidase activity in chronic myeloproliferative and myelodysplastic diseases by microscopic and photometric assays.

Neutrophil NADPH oxidase is a membrane-bound enzyme complex responsible for the reduction of oxygen to superoxide anion in the respiratory burst. Impaired neutrophil function has often been reported in myeloproliferative diseases and myelodysplastic syndromes (MDSs), but its laboratory features have not been well characterized. Traditionally, NADPH oxidase activity has been evaluated with a microscopic method by nitroblue tetrazolium salt reduction to blue-black insoluble formazan granules identified in positive neutrophils by microscopy. We investigated neutrophil NADPH oxidase in 22 patients with chronic myeloproliferative disorders (cMPDs) and 15 patients with MDSs, using the microscopic method as well as a photometric microplate assay, which monitored the cytochemical reaction for 30 min. The relationship between cMPD and patient susceptibility to infections was also investigated. In the photometric assay, the mean enzyme activity in MDSs and cMPDs was lower than in normal subjects. NADPH oxidase activity was greater in cMPDs (except myelofibrosis) than in MDSs (except chronic myelomonocytic leukemia), and these differences were less evident with microscopy. Moreover, for cMPDs, patients with susceptibility to infections showed a lower NADPH oxidase activity than patients without infections.

Adult↗
PubMed1995

Organization and results of the Veneto region (Italy) external quality assessment program for clinical chemistry.

The Veneto region EQA program has been developed on the basis of the law that created the national health service and then on the regional social-health plans. Organizer and reference laboratory is the Biomedical Research Center in Castelfranco Veneto (TV). The aim of the program is to describe the state of the art in the public and private laboratories, and to evaluate the performances of each laboratory according to the schemes recommended by the European Committee for Clinical Laboratory Standards (ECCLS). Even though the program was not obligatory, participation has always been about 80% for public laboratories and increased from 70% to almost 100% in the private ones. The results showed very good interlaboratory agreement for electrolytes; iron assay has improved in the last two years; there have been standardization problems for urea and creatinine; among enzymes, the results are good for GGT and ALT, but not satisfactory for AST and more so for ALP. Since 1990, accuracy evaluation for 9 constituents has been introduced. The results are good for electrolytes and organic constituents but standardization problems are shown for enzyme methods, especially with ALP and AST.

Chemistry, Clinical↗
PubMed1994

Sleep polygraphic parameters in neuromuscular diseases.

In a polysomnographic study of 32 neuromuscular patients-22 with a form of muscular dystrophy, 3 with a form of congenital myopathy, 4 with a form of spinal muscular atrophy, 1 with a recurrent form of polymyositis and 1 with osteogenesis imperfecta syndrome--of which 21 were nonambulatory, we observed sleep related respiratory disturbances represented by: drops in oxygen saturation (SaO2), cardiac arrhythmia, sleep disruption, apneas, tachypnea, tachycardia and snoring. Nine out of the cohort of 32 patients presented with significant desaturations periods. These patients presented with an associated restrictive syndrome and thoracic deformities, some with tachypnea and/or SaO2 below 90% during wakefulness. In this group, snoring was observed in those patients with a form of muscular dystrophy while tachypnea was observed in patients who presented the highest desaturations levels. Sleep quantification revealed an increase of stage 1 sleep coupled with a decrease or even total absence of REM sleep. This is, we believe, a likely consequence of episodic desaturations that may accompany sleep hypoventilation which is potentialised during REM sleep stage.

Adolescent↗
PubMed1993

Breathing frequency in sleep related respiratory disturbances.

In normal adults, breathing frequency (f) is highly reproducible within an individual ranging from 8 to 25 min-1; during sleep, f is known to change only minimally. This variable is rarely reported in studies of adults with various sleep related respiratory disturbances (SRRD). We occasionally observed a spectacular increase of f during sleep in patients with SRRD associated with hypopnea and 02 desaturation. We undertook a retrospective study of 650 consecutive all-night polysomnographic recordings, in order to evaluate how often such an increase in breathing frequency occurs and with which factors it is associated. We excluded patients with major respiratory failure. We found 16 patients (11 males; mean +/- SD, age: 45 +/- 13 yrs; body mass index (BMI): 44 +/- 11 kg/m2) with f > 25 min-1 during sleep (tachypneic group, T). We performed a one-for-one matching for sex, age and BMI between the T and a control (C) group (age: 45 +/- 12 yrs; BMI 44 +/- 10 kg/m2), with similar sleep disturbances but normal f during sleep. We compared the f in each vigilance state by averaging five measurements of f, each of one minute duration in a stable period. We observed that: C patients showed no significant change in f in any vigilance state; T patients showed a higher f already during wakefulness (p < 0.05) and f increased significantly in all sleep stages (< 0.01). We compared the two groups for many clinical and polysomnographic variables.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Factors causing dose variability in drug administration.

The variability of the drug dose actually given to cancer patients was analyzed. Three variability factors were quantitatively examined (body surface calculation, personalized dose calculation, and drug residuum in commercially available vials) and their variability was experimentally measured. A systematic reduction (mean, 7%; range, 2%-15%) and a random variability (4%-5%) of the dose given were demonstrated. These results draw attention to the role of some of the procedures of routine clinical activity in determining the amount of drug actually delivered. The analysis suggests that personalization of doses must be very accurate in both measurement and calculation and that the staff giving the drug needs to be carefully informed about the importance of drug residuum. The variability of the delivered dose can lead to the misclassification of patients in investigations on the dose-response relationship. This factor may be added to pitfalls previously reported to affect this type of retrospective analysis.

Antineoplastic Agents↗