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M Panteghini

Publications and source records attributed to M Panteghini.

At least 73 records · Page 4Linked to original sources
PubMed1993

Significance of various parameters derived from biological variability for lipid and lipoprotein analyses.

Analytical, within-subject, and between-subject components of variability have been determined for total cholesterol, LDL-cholesterol, HDL-cholesterol, and its HDL2 and HDL3 subfractions, triglycerides, apolipoproteins A-I and B, and lipoprotein(a) in serum specimens from a cohort of 10 healthy subjects over a 1-month period. From these data, we have calculated the desirable analytical imprecisions, the indices of individuality, the critical differences for significant change detection, and the number of specimens required to estimate the homeostatic set-point of an individual. Practically, the analytical goal for imprecision was not achieved for HDL2 subfraction, lipoprotein(a), and direct LDL-cholesterol determination (obtained vs. theoretical analytical CV, 8.2% vs. 5.9%, 7.4% vs. 3.8%, and 3.2% vs. 2.6%, respectively). All analytes had marked individuality, showing that the use of population-based reference values is inadequate for their interpretation. The applicable differences required for two results to be significantly different (p < or = 0.05) are total cholesterol: 10%; triglycerides: 49%; LDL-cholesterol: 16%; HDL-cholesterol: 14%; HDL2-cholesterol: 40%; HDL3-cholesterol: 16%; apolipoprotein A-I: 11%; apolipoprotein B: 12%; and lipoprotein(a): 29%. Furthermore, it should be clear that population screening for the assessment of risk of coronary artery disease by means of some of the assays studied would result in a significant number of patients requiring analysis of multiple specimens.

Adult↗
PubMed1993

Pre-analytical, analytical and biological sources of variation of lipoprotein(a).

The pre-analytical, analytical and biological sources of variation were estimated for serum lipoprotein(a) concentrations, as measured with a new commercially available procedure. There were no significant differences between the concentrations of lipoprotein(a) measured in EDTA plasma and serum. The analyte is stable in specimens stored for up to two weeks in the refrigerator, or up to three months at-20 degrees C. Fasting is not essential before the lipoprotein(a) determination. Data on analytical (between-run coefficient of variation < 15.7%), within-subject (8.6%) and between-subject variation (85.8%) were used to calculate the analytical goal for imprecision (< 4.3%), the critical difference between serial values from an individual that represents a significant change (36.3%), the number of specimens which should be collected to estimate the homeostatic value for an individual to within +/- 5% (26), and to establish the marked individuality of lipoprotein(a) (index of individuality, 0.1).

Adult↗
PubMed1993

Clinical and analytical evaluation of a continuous enzymatic method for measuring pancreatic lipase activity.

We report the evaluation of a new commercial kit for the determination of pancreatic lipase activity. The kit is based on the use of a 1,2-diglyceride as substrate and a specific monoglyceride lipase. The detection step is the continuous colorimetric measurement of hydrogen peroxide produced from glycerol by glycerol kinase, glycerol-3-phosphate oxidase, and peroxidase reactions. The procedure appears to be precise (between-day CV < 9%) and the results show good correlation with those obtained by alternative procedures (vs turbidimetry, r = 0.965; vs ultraviolet absorbance-enzymatic method, r = 0.995; vs Ektachem, r = 0.976; vs immunometry, r = 0.970). However, the method is susceptible to interference by increased concentrations (> 4.5 mmol/L) of serum triglycerides. We estimated the reference interval for healthy adults to be 8-44 U/L. When we evaluated clinical efficacy by using receiver-operating characteristic curves and the overlap index, no significant differences were found between the commercial kit and a common turbidimetric assay for diagnosing patients with acute pancreatitis; both methods performed satisfactorily.

Adult↗
PubMed1992

Pre-analytical and biological variability of prostatic acid phosphatase and prostate-specific antigen in serum from patients with prostatic pathology.

We determined the pre-analytical and biological variation of prostatic acid phosphatase and prostate-specific antigen in the same patient samples. Prostatic acid phosphatase and prostate-specific antigen were both stable when stored for at least 3 weeks with acidification (acetate buffer) or without acidification, except for prostate-specific antigen in samples stored unacidified at 4 degrees C. A significant elevation of prostate-specific antigen was noted in four patients with benign prostatic hyperplasia between 1/2 and 6 hours after prostatic massage. No significant effect was shown of changes in the glomerular filtration rate on prostate-specific antigen concentration, in spite of its low molecular mass. The estimate of within-subject biological variation showed a coefficient of variation of 33.8% for prostatic acid phosphatase and 14% for prostate-specific antigen. Desirable analytical imprecisions based on these findings were about 17% for prostatic acid phosphatase and 7% for prostate-specific antigen, these goals being achieved in practice for marker values higher than or equal to the upper reference limit.

Acid Phosphatase↗
PubMed1992

Electrophoretic fractionation of pancreatic lipase.

Human pancreatic isolipases were separated by electrophoresis on cellulose acetate membrane. Band visualization by fluorescence detection of NADH produced by beta-oxidation cyclic reaction of fatty acid liberated from 1,2-dilinoleoylglycerol by lipase was achieved by making a two-plate "sandwich" of an electrophoresis plate and a substrate-bearing plate. Two true lipase forms, named L1 and L2 to reflect their electrophoretic migration, were resolved with this method and quantified by densitometry. The procedure was not only simple and rapid but also precise (between-run CV less than 13.5%) and sensitive (detected lipase fractions of less than 2 U/L). L1 (mean 57% of total lipase, SD 19.3%) and L2 (mean 43%, SD 19.3%) lipase forms were found in all normal persons studied. In a preliminary clinical study of 27 emergency room patients, evaluation of the lipase electrophoretic pattern in serum did not separate patients with acute pancreatitis from those with other acute abdominal disorders.

Abdominal Pain↗
PubMed1991

Diagnostic value of four assays for lipase determination in serum: a comparative reevaluation.

We assessed the diagnostic value of four commercially available methods for determining pancreatic lipase (LPS) in serum (the turbidimetric procedure from Boehringer, two enzymatic approaches from Kodak and Poli, and an immunochemical assay) in a population of 46 hospitalized patients with acute abdominal pain. In 31 cases (67.4%), the final diagnosis was acute pancreatitis. When evaluated by means of receiver-operating characteristic (ROC) curves, no significant differences were found among the procedures. Concerning clinical efficiency, all the assays had values equal to or greater than 90%. Using the calculation of the overlap index (OI) as a statistical approach to quantify the clinical utility of various LPS assays, the test having the greatest potential for differentiating between patients with and without acute pancreatitis was the turbidimetric assay (OI = 0.14).

Acute Disease↗
PubMed1991

Clinical evaluation of an algorithm for the interpretation of hyperamylasemia.

Total amylase concentration in serum continues to be widely determined in the diagnosis of acute pancreatic disease. Accumulated experience has made clear, however, that this determination has distinct limitations. Consequently, the knowledge of the origin of hyperamylasemia may have an important influence on treatment, hospitalization, and extent of clinical investigations. We undertook a logical and systematic approach to the interpretation of hyperamylasemia through the use of an algorithm that can be applied in clinical situations without the need for the integration of radiologic procedures or clinical data. The proposed algorithm was tested for effectiveness in 97 consecutive hospitalized patients with hyperamylasemia (amylase level greater than twice the upper reference limit) for a 2-year period. The majority (52.5%) of these patients had acute pancreatitis. The algorithm assigned the correct diagnostic categories in 95.8% of cases, with a disagreement between patient diagnosis and algorithm-generated diagnosis in only four cases. These four patients (two with acute biliary disease, one with bacterial peritonitis, and one with chronic renal failure) had pancreatic lipase values greater than five times the upper reference limit, so that the algorithm classified their condition as acute pancreatitis. The clinical trial indicated that the proposed decision tree, which requires only knowledge of biochemical data that are readily available, is useful in the evaluation of elevated amylase activity and facilitates arrival at a definitive diagnosis.

Acute Disease↗
PubMed1991

Time course of changes in pancreatic enzymes, isoenzymes and, isoforms in serum after endoscopic retrograde cholangiopancreatography.

Kinetics of the catalytic activities of total amylase (AMY; EC 3.2.1.1), pancreatic (P)-AMY isoenzyme, P2 and P3 isoforms, and pancreatic lipase (LPS; EC 3.1.1.3), and of the mass concentration of LPS in serum were studied in 10 patients who underwent endoscopic retrograde cholangiopancreatography (ERCP) and showed a distinct pancreatic injury. The temporal characteristics of enzyme changes described were (a) the maximal rate (Ka) at which enzymes are released into blood, (b) the time lag from ERCP until maximum concentration value, (c) the peak value of each serum enzyme, and (d) the rate (Kd) at which each enzyme is cleared from serum. LPS activity and mass concentrations increased and decreased faster than AMY and isoamylases, and the time of the LPS peak tended to be earlier than that of the other enzymes, but not significantly. The average peak increase of LPS values was higher than that of total AMY, P-AMY, and P2 isoform (P less than 0.001). The P-AMY time-activity curve was a composite of curves attributable to its isoforms; the isoforms increased and peaked sequentially, with P3 returning to normal more slowly than did P2. LPS mass and activity concentrations showed excellent parallelism, with no important differences. At 50 h after ERCP, only LPS values still exceeded the upper reference limit, returning to normal 70 h after the examination.

Amylases↗
PubMed1991

Benign inherited hyperphosphatasemia of intestinal origin: report of two cases and a brief review of the literature.

Two families with benign hyperphosphatasemia of intestinal origin were studied and compared with six other cases reported in the literature. No evidence of clinical abnormalities or explanations for the unusual enzyme concentrations were found. Agarose gel electrophoresis of alkaline phosphatase (ALP, EC 3.1.3.1) isoenzymes in serum demonstrated markedly increased intestinal isoforms (the "soluble" and the "hydrophobic" forms), which accounted for approximately 60% of total ALP activity. The description of these families demonstrated patterns suggesting autosomal-dominant inheritance, even if the precise genetic background of the abnormality affecting the enzyme production or the control mechanisms for its entry into the circulation could not be determined. Exact recognition of this benign biochemical abnormality should help to avoid unnecessary investigation.

Adolescent↗
PubMed1990

Diagnostic value of measuring pancreatic isoamylase with a double-monoclonal antibody immunoassay in serum of hospitalized hyperamylasemic patients.

We evaluated the diagnostic utility of measuring pancreatic isoamylase (P-AMY) with a double-monoclonal antibody technique in a population of 43 consecutive hospitalized hyperamylasemic patients in comparison with serum pancreatic lipase (LPS) activity. In 27 cases (62.8%), the final diagnosis was acute pancreatitis. Predictive values were calculated for P-AMY and LPS activities, and a P-AMY percentage was calculated for selected decision levels. The maximal diagnostic efficiency was 0.930, 0.814, and 0.767 for LPS, P-AMY activity, and P-AMY percentage, respectively, indicating that serum LPS measurement was clinically superior to P-AMY for distinguishing patients with or without pancreatitis. Measurement of both P-AMY activity and percentage in serum did not significantly improve diagnostic accuracy.

Acute Disease↗
PubMed1990

Aspartate aminotransferase isoenzymes.

Aspartate aminotransferase (AST, EC 2.6.1.1) exists in human tissues as two distinct isoenzymes, one located in the cytoplasm (c-AST), and the other in mitochondria (m-AST). Striated muscle, myocardium, and liver tissues are the main sources of AST. A growing body of information suggests that determination of AST isoenzymes in human serum is useful in evaluating damage to some of these organs. In hepatic disease, the test is used to assess liver necrosis and for determining prognosis. It may also assist in identifying patients with active alcoholic liver disease. In patients with acute myocardial infarction, measurement of AST isoenzymes provides diagnostic information that differs from that obtained by determination of total creatine kinase and lactate dehydrogenase enzymes, and their isoenzymes.

Aspartate Aminotransferases↗
PubMed1990

An immunochemical procedure for determination of creatine kinase 3(1) (serum-specific) isoform in human serum evaluated.

Changes in the proportions of individual isoforms of creatine kinase (CK) in serum promptly reflect both myocardial infarction and coronary reperfusion. A new commercial kit has been introduced for measuring CK-3(1) isoform in serum (ISOFOR-MM, International Immunoassay Labs.). This is an immunochemical assay containing CK-3(1) specific monoclonal antibody, bound to magnetizable particles, used to immunoextract this isoform. The CK activity of the sample is measured before and after immunoextraction and the difference in the two values gives the measure of CK-3(1). Extraction of CK-3(1) was complete at less than or equal to 1200 U/L. Analysis of between-day imprecision gave CV between 2.9-7.9%. The method was not susceptible to interference by CK-3(2) and CK-3(3) isoforms, CK-2 isoenzyme, or mitochondrial CK. Reference interval for CK-3(1) (expressed as percent of total CK-3) was 42-69%. Correlation between percent CK-3(1) by isoform electrophoresis (x) and evaluated procedure (y) was y = 0.83x + 7.6, with r = 0.957 (n = 40). The ISOFOR-MM performed well enough in this evaluation to replace electrophoresis or isoelectric focusing for measurement of CK-3(1) isoform.

Creatine Kinase↗
PubMed1990

Evaluation of a new commercial assay kit for quantification of lactate dehydrogenase isoenzyme 1 in serum.

A new method for measuring lactate dehydrogenase (EC 1.1.1.27) isoenzyme 1 using sodium perchlorate as a chaotropic chemical selective inhibitor of all lactate dehydrogenase isoenzymes containing M-subunit was evaluated. Results with this method were precise (between-day coefficient of variation less than 9%), highly linear (coefficient of correlation = 0.9998) and correlated well with lactate dehydrogenase isoenzyme 1 as determined by the conventional immunological method (coefficient of correlation = 0.976). The reference interval for 307 healthy subjects was estimated to be 23-46 U/l (95% central range, determined non-parametrically). Being simple, convenient and amenable to automation, the method provides a substantial saving in labour and reagent costs when compared with alternative analytical approaches.

Evaluation Studies as Topic↗
PubMed1990

A two-tube immunochemical method for determination of CK-MB isoenzyme in serum evaluated.

A new commercial kit (Impres-MB; International Immunoassay Labs.) recently was introduced for measuring the MB isoenzyme of creatine kinase (CK-MB) based on the use of monoclonal antibodies. After antibodies to CK-MM isoenzyme are added to precipitate the CK-MM, antibodies to CK-M monomer are added to precipitate the M-subunit isoenzymes of CK. Subtracting the enzymatic activity of the second supernate from the residual activity in the first yields the activity of CK-MB. Results are not affected by CK-BB, mitochondrial CK, or adenylate kinase. However, the anti-CK-MM antibodies precipitated only about 98% of serum CK-MM and may have partly precipitated CK-MB isoenzyme (average analytical recovery of CK-MB, 86.6%). Comparison between Impres-MB (y) and electrophoresis (x) yielded the following linear-regression equation: y = 0.79x + 3 (r = 0.982, n = 97). Data for CK-MB temporal kinetics, obtained from patients with myocardial infarction, correlated significantly in both methods; however, peak activity values of CK-MB were significantly different, confirming that the difference between the new method and the electrophoretic method average 20%.

Adult↗