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F Dati

Publications and source records attributed to F Dati.

At least 37 records · Page 2Linked to original sources
PubMed1991

International Federation of Clinical Chemistry standardization project for measurements of apolipoproteins A-I and B.

To minimize differences in apolipoprotein measurements among laboratories and methods, a standardization program involving common suitable reference material is needed. The Committee on Apolipoproteins of the International Federation of Clinical Chemistry initiated a collaborative study for the standardization of test systems for measuring apolipoproteins (apo) A-I and B, with 25 company laboratories and three research laboratories involved in apolipoprotein analysis to: (a) evaluate calibration differences among the test systems; (b) evaluate whether comparability of the data can be achieved with the use of frozen serum pools to recalibrate the different systems; and (c) evaluate and select suitable candidate reference material. We used 26 test systems for apo A-I and 28 for apo B. Relatively modest differences were found in calibration for apo A-I, but very wide differences were observed for apo B methods. After uniform calibration, the overall among-laboratory CV for apo B decreased from 19% to 6%. Three lyophilized serum preparations for apo A-I and three liquid-stabilized serum preparations for apo B were selected for further evaluation as candidate international reference materials.

Apolipoprotein A-I↗
PubMed1990

Standardization of commercial assays for serum Apo A-I and Apo B: a consensus procedure for the calibration of reference materials.

Commercial apolipoprotein A-I and B assays show a broad variation of results. This is particularly evident for the different Apo B test kits available commercially. The cause of these differences is mainly due to the inadequate international standardization of apolipoprotein assays. A common effort is at present made by commercial organizations within the International Federation of Clinical Chemistry together with the IFCC Committee on Apolipoproteins to achieve a consensus on a practical standardization procedure for apolipoprotein measurements. The aim is to calibrate all commercially available Apo A-I and Apo B test kits using frozen serum pools (at three levels) previously standardized against primary reference materials. Secondary serum reference materials (at three different concentrations) (SSRM) will be selected among those offered by industrial organizations to serve as "International Master Calibrators". These will replace the Interim Serum Reference Materials (frozen serum pools) which cannot be delivered indefinitely. The secondary serum reference materials will be used by all commercial organizations to control the validity of their own calibrations.

Apolipoprotein A-I↗
PubMed1990

[Standardization of the immunochemical detection of apolipoprotein A-I and B].

Apolipoprotein A-I, the major protein of high-density lipoproteins, and apolipoprotein B, the major protein of low-density lipoproteins can serve as important predictor of the risk of cardiovascular diseases. The lack of an internationally valid standardization is a serious impediment to a broad application of the apolipoprotein measurements in the laboratory diagnosis of atherosclerosis. A common effort is at the present made by the IFCC Committee on Apolipoproteins together with several commercial organizations to achieve a consensus on a practical standardization procedure for the measurement of apolipoprotein A-I and B. The aim is a) to calibrate all commercially available Apo A-I and Apo B test kits using frozen serum pools previously standardized against primary reference materials and b) to select the secondary serum reference preparations which will substitute the frozen serum pools and will be used for the control of the validity of the own calibration. The available results from a preliminary exercise prove with a variation less than 5% for Apo A-I and less than 8% for Apo B with patients' samples that the use of common reference materials leads to the harmonization of the results obtained with different test systems for measurement of apolipoprotein A-I and B.

Apolipoprotein A-I↗
PubMed1990

[Standardization of the thromboplastin time determination].

The results of our studies prove that today it is possible for manufacturers of thromboplastin preparations to follow the international recommendations for standardization of methods for prothrombin time determination. This is valid not only for the PT reagents for coagulometric techniques but also for those for photometric techniques. New manufacturing processes allow to produce sensitive thromboplastins which can be calibrated according to the recommendations of international standardization committees. Calibrated thromboplastins enable introduction of a common scale (INR) for the control of the intensity of the oral anticoagulation. The INR system improves the comparability of the therapeutical ranges recommended from different organizations and from manufacturers of thromboplastin, so that the continuity of the oral anticoagulant therapy of patients even in different countries will be decisively improved.

Calibration↗
PubMed1989

Serum levels of alpha-1 microglobulin in recipients of renal allografts.

Serum levels of alpha 1 microglobulin (s-alpha 1 m) in 92 recipients of renal transplants were elevated during pretransplant uremia (P less than 0.001), acute rejection (P less than 0.01), and cyclosporin-induced nephrotoxicity (P less than 0.01). In patients with stable renal function, those treated with cyclosporin had higher s-alpha 1 m than those receiving azathioprine: 81 +/- 4 and 64 +/- 3 mg/l (mean +/- SEM), respectively (P less than 0.05). The serum creatinine levels were 127 +/- 5 and 115 +/- 7 mumol/l (mean +/- SEM), respectively (N.S.). Two of the patients with normal serum creatinine had normal s-alpha 1m levels. There were positive linear correlations between s-alpha 1m and serum creatinine levels during stable renal function, rejection, cyclosporin-induced nephrotoxicity, and cytomegalovirus infections (r = 0.7-0.8, P less than 0.01-0.001) and between s-alpha 1m and beta 2 microglobulin (beta 2m) during the same conditions (r = 0.5-0.8, P less than 0.01-0.001). During infections, serum creatinine and beta 2m increased (P less than 0.001), but s-alpha 1m did not. S-alpha 1m values did not distinguish between rejection and cyclosporin-induced nephrotoxicity. It is concluded that s-alpha 1m might be a valuable complement to serum creatinine levels in the evaluation of renal function in renal transplant recipients.

Adolescent↗
PubMed1989

New trends in the field of coagulation diagnosis--new possibilities to improve monitoring of antithrombotic therapy.

Two specific and sensitive enzyme immunoassays have been developed for the measurement of TAT and PTF, respectively. The TAT-ELISA uses two different antibodies binding selectively to the corresponding antigen moieties of TAT; anti-PTF antibodies were obtained from rabbits using a synthetic peptide from the COOH-terminus of PTF. Concentration in plasma samples of healthy individuals was found to be 1.45 +/- 0.4 micrograms/l for TAT, and 0.65 +/- 0.2 nMol/l for PTF. Patients with coagulation disorders showed markedly increased concentrations of both TAT and PTF. It can be assumed that these parameters might be suitable indicators for monitoring of both anticoagulant and thrombolytic therapy.

Amino Acid Sequence↗
PubMed1988

Good biocompatibility of the polyamide hemofilter.

Chronic hemofiltration (HF) is now a well-established method, especially for elderly uremic patients and those suffering from cardiovascular problems. This is due to the fact that chronic HF offers superior treatment comfort with less hypotensive episodes, vomiting, muscle cramps and febrile reactions. Apart from the different blood purification techniques involved in chronic HF compared to hemodialysis (i.e. convection versus diffusion), it might well be that the better treatment comfort is attributable to a certain extent to the polyamide HF membrane used in our HF treatments. We studied different biocompatibility parameters and received the following data: (a) leukocytes and thrombocytes remained unchanged during a treatment session; (b) elastase increased slightly but there was no difference between the polyamide and polycarbonate membrane, and (c) arterial and venous concentrations of C5a and C3d remained almost unchanged. The superior treatment comfort and better vascular stability of HF over hemodialysis might also be due to the improved biocompatibility of the applied hemofilter as the polyamide membrane induces no changes in different biocompatibility parameters such as leukocytes, thrombocytes, C5a or C3d.

Biocompatible Materials↗
PubMed1988

The ontogeny of serum immunoreactive pancreatic lipase and cationic trypsinogen in the premature human infant.

We evaluated the development of the exocrine pancreas in 16 healthy preterm infants (29.3 +/- 1.6 weeks). The infants were fed breast milk with formula supplements (n = 8) or formula alone (n = 8). Growth was monitored weekly for 12 weeks then at 3, 6, 9, 12 months. At the same intervals sera were determined for pancreatic lipase and cationic trypsinogen. In addition, cord blood samples were analysed from another 33 preterm (27.6 +/- 5.2 weeks) and 75 healthy full-term infants. Serum pancreatic lipase in the cord blood of term (3.7 +/- 0.4 micrograms/l) and preterm infants (1.8 +/- 0.2 micrograms/l) was significantly below values reported for older children (10.5 +/- 0.9 micrograms/l; p less than 0.001). In the preterm infant, serum lipase was also significantly lower than values obtained at term (p less than 0.001). At birth, serum trypsinogen for preterm (16.8 +/- 1.3 micrograms/l) and term infants (23.3 +/- 1.9 micrograms/l) were below those for older children (31.4 +/- 3.7 micrograms/l; p less than 0.05). Over the first 3 weeks of life, serum lipase and trypsinogen increased significantly. From 3 weeks to 12 months of age, serum trypsinogen values remained unchanged, but serum lipase increased dramatically after 10 weeks of age. Thus, at 6 and 12 months of age, the preterm infants had significantly higher serum lipase values than infants of the same age born at term. These two pancreatic enzymes appear to show independent age-related maturation in infants born before term. The rate of maturation of lipase appears to be accelerated by exposure to the extrauterine environment.

Aging↗
PubMed1988

New perspectives in diagnosis of hemostasis disorders.

The classical coagulation analyses are performed either by using manual methods or by means of various instruments with a different degree of automation. The introduction of chromogenic peptide substrates which can be split by thrombin has led to the development of photometric assays for PT and aPTT determination independent from the fibrinogen concentration and from its conversion to fibrin. After that, turbidimetric methods for the determination of fibrinogen, thrombin time and batroxobin time have been set up allowing the use of photometry for the determination of the most important hemostaseological parameters. For such purposes a new analytical system (ChromoTimeSystem, Behringwerke AG, Marburg/FRG) based on a special instrument and reagents for chromogenic and turbidimetric methods for coagulation and fibrinolysis has been developed. The ChromoTimeSystem allows to perform by photometry all important tests for coagulation and fibrinolysis. The analytical characteristics of this new system are presented.

Blood Coagulation Disorders↗
PubMed1988

Present status of standardization in coagulation assays for control of oral anticoagulation.

Recently, recommendations for the production of thromboplastins have been issued by International Committees (ICSH/ICTH) to achieve a standardization of prothrombin time assays. Following such recommendations we have standardized two new PT reagents based on coagulometric and photometric methods which rely on the same sensitive human placental thromboplastin. Both PT reagents have been optimized especially for use in oral anticoagulant therapy. They offer high sensitivity and reproducibility, accurate lot standardization and therefore internationally comparable values by the expression of the ISI value of each reagent batch.

Administration, Oral↗
PubMed1987

Multicenter evaluation of a chromogenic substrate method for photometric determination of prothrombin time.

A multicenter study of a chromogenic substrate method for photometric determination of prothrombin time was conducted in order to evaluate its clinical application. Seven laboratories participated in the study using a total of 742 plasma samples from 417 patients on oral anticoagulant therapy, 261 healthy subjects and 64 patients with different diseases especially of the liver as well as 30 patients with hereditary deficiency of coagulation factors II, V, VII, X. The chromogenic PT method was compared to a standardized coagulometric PT assay which uses the same sensitive human placenta thromboplastin calibrated against international reference preparations. A high correlation of the prothrombin ratio values of the chromogenic and the coagulometric assay was obtained in 402 plasma samples (r = 0.940; y = 1.02x - 0.1). The study showed that the chromogenic PT reagent is sensitive to deficiency of the coagulation factors of the extrinsic pathway but not affected by heparin up to 1 IU/ml because of the heparin antagonist added. The precision (coefficient of variation) of the photometric method ranged between 0.6 and 3% (intraassay CV) and between 1.4 and 5.8 (interassay CV). The International Sensitivity Index (ISI) obtained for the used lot was 1.09. The therapeutical range in percentage activity for patients in a stable phase of an anticoagulant therapy was found to be from 15 to 27 percent of normal. The results of the clinical evaluation proved the good comparability of the new chromogenic PT test with coagulometric methods, its high factor sensitivity, good reproducibility and easy performance.

Anticoagulants↗
PubMed1987

[Determination of thromboplastin time with a new standardized thromboplastin from human placenta: results of a cooperative study].

In five centres a new sensitive standardized thromboplastin from human placenta (Thromborel S) for determination of prothrombin time (PT) was evaluated on plasmas from healthy subjects, from patients on oral anticoagulant therapy and from patients with different diseases, especially of the liver. The standardization of the human placenta thromboplastin (HPT) for prothrombin time determination was performed by comparison with a lot of the Reference Preparation British Comparative Thromboplastin (BCT). The obtained International Sensitivity Index (ISI) for 14 differents lots of the new thromboplastin varied between 1.04 and 1.29 (mean value: 1.16). The reagent is highly sensitive to the factors of the extrinsic coagulation pathway and is not affected by heparin at least up to 0.6 IU/ml. From the comparison with the British Comparative Thromboplastin lot No. 235, a therapeutical range for the stable phase of the oral anticoagulation of 2.4-4.0 prothrombin ratio or 15-27% of normal, respectively, was obtained. Comparison of prothrombin time determination using the Human Placental Thromboplastin and the British Comparative Thromboplastin lot No. 235 in 330 patients on oral anticoagulation showed good correlations either in "percent normal" or in prothrombin ratio.

Anticoagulants↗
PubMed1986

Evaluation and comparison of cathodic trypsin-like immunoreactivity, pancreatic lipase and pancreatic isoamylase in the diagnosis of acute pancreatitis in 849 consecutive patients with acute abdominal pain.

In 849 patients (417 men, 432 women) consecutively hospitalized with acute abdominal pain we compared the value of serum cathodic trypsin-like immunoreactivity, pancreatic lipase (EC 3.2.1.3) and pancreatic isoamylase (EC 3.2.1.1) as diagnostic tests for acute pancreatitis. The diagnoses of acute pancreatitis (in 49 patients, 5.8%) and other diseases were made without knowledge of these enzyme values. When evaluated by means of receiver operating characteristic curves no differences were found in diagnostic performance of the three enzymes. Use of combinations of different enzymes had no advantage over single enzyme determination using discrimination analysis for evaluation. The highest efficiency was for all three enzymes 0.991 (95% confidence limits: 0.983-0.995) and for all three enzymes the discrimination value giving this efficiency was several times the upper limit of reference range: 1 779 micrograms/l for cathodic trypsin-like immunoreactivity, 831 U/l for pancreatic isoamylase and 316 micrograms/l for pancreatic lipase. None of the enzymes had any prognostic value at admission in predicting a mild or severe attack of acute pancreatitis. In conclusion, no single enzyme or combination of enzymes had any diagnostic advantage for acute pancreatitis in patients with acute abdominal pain. Thus selection of one of the three enzymes as diagnostic test of acute pancreatitis is to be based on considerations such as economy, methodological simplicity, possibility of automated assay and the time-consumption at the assay.

Abdomen↗