THE DISCRIMINATIVE ABILITY OF PERCENT FREE PSA IN PATIENTS WITH PSA > 10 NG/ML

Objective To study the discriminative role of % free PSA in patients with a total PSA > 10 ng/ml. Patients and Methods Our patient cohort con-sisted of 90 males aged between 45 and 81 years (mean age: 67 ± 9 years). All patients had a biopsy-proven prostate pathology. Fifty-six patients had BPH (Group I) while 34 had prostate cancer (Group II). Blood samples were collected from all patients, and total PSA, free PSA and % free PSA were calculated in all specimens. Total PSA was measured using the Imx assay (Abbott, USA). The significance of the differences between the groups was assessed by the Mann-Whitney Wilcoxon rank sum test and Spearman's correlation coefficient for the correlation between % free PSA and the pathological diagnosis. Results The difference in total PSA between the two groups was insignificant. The mean value in BPH patients was 11.7 ± 11.4 ng/ml, while in patients with prostate cancer its was 15.8 ± 19.2 (p = 0.8). The mean % free PSA was 18 ± 1% in patients with BPH and 16 ± 0.6% in patients with prostate cancer (p = 0.3). A strong correlation was evident between % free PSA 15% and the pathological diagnosis (p = 0.87). This was also true for the cutoff values of 20% and 25% (p=0.79 and 0.62, respectively). Conclusion As a diagnostic test, % free PSA alone cannot be used for the discrimination of BPH from prostate cancer. In patients with a total PSA > 10 ng/ml, % free PSA has no value in the discrimination between benign and malignant pathology. Les Possibilités Discriminatives de la Fonction Libre de PSA chez les Patients dont le Taux de PSA est > 10mg/ml. Objectifs : Etude du rôle discriminatif de la fraction libre de PSA pour les patients dont le taux de PSA est supérieur à 10 mg/ml. Patients et Méthodes : Il s'agit d'une cohorte de 90 patients de sexe masculin âgés de 45 à 81 ans avec une moyenne d'âge de 67 ± 9 ans. Tous les patients ont subi des biopsies prostatiques avec étude histopathologique : 56 patients présentent une HBP (Groupe I) et 34 patients un cancer de la prostate (Groupe II). Un prélèvement de sang a été réalisé chez tous les patients avec un dosage du PSA total et de la fraction libre de PSA. Le PSA total a été mesuré par un kit IMX ( Abott, USA). L'étude statistique a été réalisée utilisant le Mann-Whitney Wilcoxon Rank test pour l'étude de la significativité de la différence entre les 2 groupes et le coefficient de corrélation de Spearman pour l'étude de la corrélation entre le rapport PSA libre/PSA totale et le diagnostic histologique. Résultats : La différence du PSA total entre les 2 groupes n'est pas significative. La moyenne des chiffres de PSA total dont l'anatomopathologie des biopsies a conclu à un cancer prostatique était de 11,7 ± 11,4 ng/ml alors que la moyenne chez le 2ème groupe présentant un cancer prostatique était de 15,8 ± 19,2 (P=0,8). La moyenne des rapports PSA libre/PSA total était de 18 ± 1% pour les patients présentant une HBP alors qu'elle était de 16 ± 0,6 % pour les patients présentant un cancer prostatique (P = 0,3). Une corrélation non significative a été remarquée entre un rapport PSA libre/PSA total de 15 % et le diagnostic histopathologique (P = 0,87). Ceci a été aussi vérifié pour une valeur charière de 20 % et 25 % (P=0,79 et 0,62 respectivement). Conclusion : Comme test diagnostic le rapport PSA libre / PSA total n'a pas de valeur discriminative entre une pathologie bénigne de la prostate et un cancer prostatique. African Journal of Urology Vol.9(1) 2003: 24-2

Precise troposphere delay model for Egypt, as derived from radiosonde data

Tropospheric delay computation is necessary to improve GPS measurements accuracy. Precise determination of these propagation delays requires knowledge of the full refraction profile at signal path. In the present research, precise troposphere slant delay model (PTD) is derived based on ten stations of radiosonde data well-distributed over and around Egypt. To derive the PTD, the troposphere is divided into regular small layers. Ray tracing technique of actual signal path traveled in the troposphere is used to estimate tropospheric slant delay. Real GPS data of six stations in 8-day period were used for the assessment of zenith part of PTD model against the available international models. These international models include Saastamoinen, Hopfield, and the local Egyptian dry model proposed by Mousa & El-Fiky. The data were processed using Bernese software version 5.0. The closure error results indicate that the PTD model is the best model in all session, but when the available radiosonde stations are less, the accuracy of PTD model is near to classic models. As radiosonde data for all ten stations are not available every session, it is recommended to use one of the regularization techniques for database to overcome missing data and derive consistent tropospheric delay information

Thermal hydraulic analysis of core flow bypass in a typical research reactor

The main objective of nuclear reactor safety is to maintain the nuclear fuel in a thermally safe condition with enough safety margins during normal operation and anticipated operational occurrences. In this research, core flow bypass is studied under the conditions of the unavailability of safety systems. As core bypass occurs, the core flow rate is assumed to decrease exponentially with a time constant of 25 s to new steady state values of 20, 40, 60, and 80% of the nominal core flow rate. The thermal hydraulic code PARET is used through these calculations. Reactor thermal hydraulic stability is reported for all cases of core flow bypass. Keywords: Thermal–hydraulics, MTR reactors, Core flow bypas