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PubMed1998

Reproducibility of 99Tcm-MAG3 clearance in normal volunteers with the two-sample method: comparison with 131I-OIH.

The aim of this study was to evaluate the reproducibility of 99Tcm-mercaptoacetyltriglycine (99Tcm-MAG3) clearance and to compare it with that of 131I-orthoiodohippurate (131I-OIH), which is widely used in clinical practice. Twelve young healthy volunteers with a mean age of 23.4 years (range 19-28) were enrolled in the study. The investigations were repeated at an interval of 1 month under similar physiological conditions. Each volunteer received a simultaneous injection of 99Tcm-MAG3 and 131I-OIH that was commercially available in an already labelled form. Blood samples were obtained at 44 and 104 min post-injection. Clearance values were calculated using the two-sample method. The mean (+/- S.D.) change from the first to the second measurement was -7.1 +/- 11.1% for 99Tcm-MAG3 and 1.7 +/- 13.6% for 131I-OIH. There were no significant differences between the first and the second measurements of 99Tcm-MAG3 and 131I-OIH clearance, respectively. 99Tcm-MAG3 clearance was shown to be very similar to that of 131I-OIH in healthy volunteers.

Adult↗
PubMed1990

Stroma-free hemoglobin solutions prepared by crystallization and ultrafiltration methods; comparison of composition and coronary vasoconstrictor potency.

Stroma-free hemoglobin solutions (SFHS) were prepared by the crystallization and ultrafiltration methodologies. The preparations were partially characterized with respect to their effects upon the isolated perfused rat heart. SFHS prepared by ultrafiltration is characterized by a substantially lower content of residual membrane phospholipid and a more restricted protein composition. This preparation is also essentially free of vasoconstrictor and contractility-depressant actions on the ex vivo perfused heart. In contrast, crystallization-produced SFHS is less well purified of both phospholipid and protein constituents, is likely to generate denatured protein aggregates during storage and exhibits vasoconstrictor and contractility-depressant activity which may vary significantly, from batch to batch. These findings indicate that preparative methodology based on ultrafiltration and size-exclusion, yields SFHS which is superior in these respect to that produced by a crystallization method.

Animals↗
PubMedDate not supplied

A multi-allergen ELISA screening method. Comparison with Pharmacia CAP system and Phazet skin prick test.

Eighty consecutive subjects, coming to our service as suffering from conjunctivitis and/or rhinitis and/or asthma, were investigated by a new multi-allergen enzymatic screening immunoassay (Profilo, Bio-Allergy, Rome, Italy) regarding to serum specific IgE for groups of inhalant allergens (Dermatophagoides, Parietaria, grasses, trees, animal danders). These groups include allergens which are most frequently responsible of allergy in our country. Indices of diagnostic accuracy of this assay were analyzed in relation to skin prick test (SPT, Phazet, Pharmacia), as in vivo reference test, and Pharmacia CAP System, as in vitro reference test, comparing the results achieved by these tests in the same group of subjects. Profilo showed high significant (p < 0.0005) correlations and satisfactory indices of diagnostic accuracy (sensitivity, specificity, predictive values of positive and negative, and efficiency) for the tested allergens with reference to both Phazet SPT and CAP System. In addition, the method appeared very rapid and simple, so that it could be performed in the physician's office.

Adolescent↗
PubMed1995

[Antegrade or retrograde blood cardioplegic method: comparison of postsurgical right ventricular function and conduction disturbances].

This study was undertaken to compare postsurgical right ventricular function and the occurrence of conduction disturbances after employing cold blood antegrade or retrograde cardioplegia during open heart surgery. Thirty-four patients were divided into AC (antegrade) and RC (retrograde) groups for the difference of route for delivery of cardioplegic solutions. Preoperative evaluation of cardiac and respiratory function revealed to be equal characteristics between the groups. Postoperatively, A-aDO2 and respiratory index (RI) as functional parameters of oxygenation capacity, LVSWI, RVSWI, dosage of dopamine and conduction disturbances were monitored at 0, 3, 6, 12 hours after termination of cardiopulmonary bypass and at extubation period. Although the recovery of respiratory function and left ventricular function were similar in both groups, temporal suppression of right ventricular function was indicated in RC group during early period after surgery, and then recovered to the same values of AC group within 3 hours. In RC group, several type of conduction disturbances were detected in 28 per cent of patients. But none of the persistent conduction disturbances were remained in all patients. We suggest retrograde coronary sinus perfusion may emerge as a valuable alternative to antegrade methods for delivery of cardioplegia.

Blood↗
PubMed1992

Determination of hippocampal protein kinase C using a frozen tissue method: comparison of synaptosomal and total activity in C57BL/6 and DBA/2 mice.

A slow freeze/fast thaw tissue preparation gave analogous hippocampal protein kinase C (PKC) activity to a fresh tissue preparation in both C57BL/6 and DBA/2 mice. Both the frozen and fresh preparations demonstrated a 28% reduction in membrane-bound PKC activity in DBA compared to C57 mice which supports our previous findings (14). This DBA-associated reduction was found only in total PKC and not synaptosomal PKC activity suggesting that the PKC difference between C57 and DBA mice may be primarily postsynaptic. This investigation shows that (1) PKC activity obtained from a slow freeze/fast thaw preparation is analogous to activity obtained from fresh tissue and (2) analysis of PKC activity in both a total and synaptosomal preparation may provide additional characterization of PKC differences such as that observed between C57 and DBA mice.

Animals↗
PubMed1989

[Quantitation of plasma 17-beta estradiol using an immunoenzyme method. Comparison with a specific radioimmunoassay].

Estradiol-17 beta (E2) was assayed on plasma samples with an enzyme immunoassay kit and results were compared with values obtained from a specific radioimmunoassay. An overall and specimen-dependent underestimation is found, confirmed by cold E2 recovery experiments. Such a kit is not entirely reliable in ovulation induction monitoring, specially for definition of hCG administration timing.

Chorionic Gonadotropin↗
PubMed1982

[Haemagglutination inhibition test: improvements, limits and advantages of the method. Comparison with neutralization test].

In this study, we report some technical improvements which enable us to envisage wider use of the haemagglutination test and haemagglutination inhibition of the rabies virus. Moderated trypsination of sensitive red blood cells and their counting are important parameters. An interesting application of the test was the haemagglutination competition enabling the amount of soluble glycoprotein (obtained during the fractionating of the virus components) to be evaluated. From antibody kinetics of vaccinated dogs, a study of the correlation which exists between the IHA titres, SN mice titres and SN-RFFIT titres was carried out. Satisfactory correlation was obtained between these three techniques.

Animals↗
PubMed1999

Creatine kinase 2 mass measurement: methods comparison and study of the matrix effect.

Five different commercial immunoassays for the measurement of creatine kinase isoenzyme 2 mass concentration were compared using human plasma samples covering a wide range of creatine kinase 2 concentrations. The immunoassays studied differ in the detection systems, in the specificity of the antibodies and in the calibrators used. Intermethod comparison by regression analysis showed differences in the results of creatine kinase 2 mass concentration. The following ratios were deduced from the obtained equations: Elecsys=1.10xImmulite=1.20xIMx=1.26xACS:180= 1.33 x Stratus. The commutability of different materials prepared by diluting purified human creatine kinase 2 in biological and synthetic matrices was studied using the different immunoassays in comparison with human plasma specimens. Almost all the materials tested were not commutable.

Calibration↗
PubMed1999

Quantification of MUC1 in breast cancer patients. A method comparison study.

OBJECTIVE: To compare the performance of four serum assays for the quantification of MUC1 in breast cancer patients. STUDY DESIGN: A total of 282 serum samples were evaluated with two automated (Boehringer Mannheim Enzymun-Test CA 15-3 and Chiron ACS BR) and two manual assays (Centocor CA 15-3 radioimmunoassay [RIA] and Biomira Truquant BR RIA). Sera were obtained from healthy controls (n=50), patients with benign (n=25) and malignant breast disease (n=77) and patients with other malignancies (n=69). In addition, sera from pregnant women (n=56) and patients with liver cirrhosis (n=5) were included. RESULTS: Intraassay coefficients of variation (C.V.s) were highest for the manual Centocor CA 15-3 assay (7.4% for values below 50 kU/l and 8.1% for values above 180 kU/l). Interassay C.Vs were highest for the manual Truquant BR assay (11.7% for the lower concentration values and 18.6% for the higher concentration values). False positive rates ranged between 0% for the Centocor CA 15-3 RIA and 14% for the ACS BR assay (cut-off: 30 kU/l). In monitoring breast cancer patients all four assays show similar patterns, although absolute MUC1 values found may differ up to 50%. CONCLUSION: For monitoring purposes all assays perform equally well, however, automated assays show lower inter- and intraassay variability, especially in the higher value range. Therefore we recommend the use of the same, automated, assay for quantification of MUC1 during the follow-up of breast cancer patients.

Biomarkers, Tumor↗
PubMed1997

Conformational analysis of glutamic acid analogues as probes of glutamate receptors using molecular modelling and NMR methods. Comparison with specific agonists.

The activity of five glutamic acid analogues substituted in position 3 or 4 by a methyl (3T, 3E, 4T, and 4E) or a methylene group (4M) has been examined at one cloned Glu receptor subtype, mGluR1. These analogues interact with glutamate receptors of the central nervous system, especially the ligand 4T [(2S,4S)-4-methylglutamic acid] at the metabotropic glutamate receptor mGluR1. It was observed that only the 4T isomer is as potent an agonist as glutamic acid, whereas other isomers are less active. Furthermore, 4E [(2S,4R)-4-methylglutamic acid] exhibited an exceptional selectivity for the KA ionotropic receptor subtype while 4M [(2S)-4-methyleneglutamic acid] was active at the NMDA receptors. These molecules represent suitable tools among a population of similar glutamate analogues for a classical structure-function relationship study. We have undertaken a conformational analysis by 1H and 13C NMR spectroscopy and molecular modelling of these molecules. Hetero- and homonuclear coupling constants were measured in order to assign the diastereotopic methylene protons at C(3) or C(4), and used for comparison in molecular dynamics (MD) simulations. The hydrogen-bonding possibility, steric effects or electrostatic interactions may be a considerable influence in stabilizing a conformational population in D2O solution. The conformations may be grouped by the two backbone torsion angles, chi 1 [alpha-CO2(-)-C(2)-C(3)-C(4)] and chi 2 [+NC(2)-C(3)-C(4)-gamma CO2-] and by the two characteristic distances between the potentially active functional groups, alpha N(+)-gamma CO2- (d1) and alpha CO2(-)-gamma CO2- (d2). The conformational preferences in solution of 4T, 4E and (3T, 3E, 4M) are discussed in the light of the physical features known for a specific metabotropic agonist (ACPD) and specific ionotropic agonists (KA) and (NMDA), respectively.

Animals↗
PubMed2002

Induction of vitellogenesis in 17alpha-ethinylestradiol-exposed rainbow trout (Oncorhynchus mykiss): a method comparison.

Juvenile rainbow trout, Oncorhynchus mykiss, were exposed to the synthetic estrogen 17alpha-ethinylestradiol (EE(2)) through injection (1, 10, 25 and 50 microg EE(2)/g fish/week) and via water exposure (1, 10 and 100 ng EE(2)/l). After seven (injection and water exposure) and 14 days (only for water exposure), blood and plasma vitellogenin concentrations were quantified using indirect endpoints, i.e. plasma alkaline-labile phosphorus (ALP), plasma protein and plasma calcium. In addition, the relative gonad (GSI) and liver weight (HSI) were recorded. Actual plasma vitellogenin concentrations were measured with an enzyme immunoassay. Only fish injected with 50 microg EE(2)/g fish had a significantly higher gonad weight. No concentration-dependent changes in the HSI were detected in fish exposed via the water, but a significant dose-dependent increase of the HSI was observed in fish injected with EE(2). Exposure of rainbow trout to EE(2) had a significant effect on all tested plasma parameters. Plasma protein, phosphoprotein and calcium concentrations were significantly higher after two weeks exposure to 100 ng EE(2)/l. Fish injected with 10, 25 and 50 microg EE(2)/g fish exhibited increased plasma protein concentrations after 1 week. Compared to the controls, plasma ALP and calcium levels were significantly higher in all injected fish. A significant and positive correlation was observed between all three plasma parameters and between these indirect parameters and the actual plasma vitellogenin concentrations. These findings indicate that both the plasma ALP and the plasma calcium assay have a similar sensitivity as that of available antibody-based assays (EIA), at least in EE(2) exposure studies, and thus these assays can provide a rapid, simple and cost-effective alternative to available immunoassays.

Animals↗