Development and evaluation of a liquid chromatography-mass spectrometry assay and its application for the assessment of renal function.

In the present study we evaluated two commonly used iodinated contrast agents, iohexol and iodixanol, as potential markers of impaired renal function. A reversed phase LC-MS method has been developed in order to separate and quantify the two substances. The assay was linear between 0.02 and 9.7 micromol/L for iohexol and between 0.4 and 49.3 micromol/L for iodixanol (r(2) > 0.998). The recovery during sample preparation ranged from 89.1 to 112.4%. The intra- and inter-assay RSD values were 3.06-13.6% for iohexol and 4.32-12.7% for iodixanol. The validated method was subsequently applied to 17 patients scheduled for angiographic procedure displaying normal and impaired renal function. A mixture of iohexol and iodixanol was intra-arterially injected and their corresponding plasma levels were determined periodically over a 24h period following administration. The elimination of both contrast agents followed by the LC-MS approach allowed us to discriminate between patients with normal and impaired renal function at 4, 8 and 24h after administration. Our preliminary results support the predictive value of iohexol and/or iodixanol clearance in a clinical environment to screen and identify patients at risk of developing CIN.

Methods for studying the biochemical properties of an Inr element binding protein: TFII-I.

Transcription initiation in eukaryotic mRNA coding genes is brought about by a host of general transcription factors, which assemble into a functional preinitiation complex (PIC) at the core promoter region, and gene-specific factors, which exert their effects on the rate and/or stability of the PIC. The core promoter region consists of a well-characterized TATA box and/or a less well-characterized pyrimidine-rich initiator element (Inr). While the biochemical mechanisms of TATA-mediated transcription initiation are extensively studied and known to be directed by the TATA binding protein, the mechanisms via the Inr element are poorly understood, as several factors have been shown to bind to an Inr. Here, we describe the biochemical properties of an Inr binding protein, TFII-I, employing the naturally occurring TATA-less but Inr-containing promoter derived from the T-cell receptor beta chain gene (V beta).

Low bone mineral density in adults with previous hypothalamic-pituitary tumors: correlations with serum growth hormone responses to GH-releasing hormone, insulin-like growth factor I, and IGF binding protein 3.

The adverse consequences of growth hormone (GH) deficiency (GHD) on bone growth in children is well described. Whether adult GHD is associated with bone loss is unknown. We evaluated 14 patients with hypothalamic-pituitary tumors (HPT) acquired during adulthood (5 men, 9 women; mean age = 48.1 +/- 4.6 years; mean BMI = 28.8 +/- 1.7) and 14 age-, sex-, and weight-matched controls. Nine HPT patients were receiving gonadal steroid replacement therapy for a mean of 11 years. All subjects had basal IGF-I and IGFBP-3 levels prior to testing with GH-releasing hormone [1 microgram/kg IV bolus; responses expressed as maximum percentage increase above baseline (PERGH)]. Bone mineral density (BMD) of the spine, hip, and total body were measured by dual-energy X-ray absorptiometry. Mean BMD Z-scores of the HPT patients were significantly lower in the femoral neck, Ward's triangle, and trochanter than in controls (all P < 0.05). Mean total body BMD (g/cm2) was also lower in the patient group (1.04 +/- 0.03 versus 1.13 +/- 0.03, P < 0.05). For the subgroup of HPT patients receiving conventional gonadal steroids, mean BMD Z-scores of the lumbar spine also were significantly lower than controls (-1.84 +/- 0.43 versus -0.57 +/- 0.46, P < 0.05). PERGH and IGF-I were correlated with Z-scores of the femoral neck (r = 0.47, P < 0.01; r = 0.45, P < 0.01) and Ward's triangle (r = 0.47, P < 0.01; r = 0.41, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium oxalate precipitation in urine following T.U.R. with glycine as irrigation fluid.

Precipitation of calcium oxalate was studied in a group of ten patients who underwent transurethral prostatectomy with glycine irrigation. Post operatively all patients showed hyperoxaluria; 60% with oxaluria higher than 10 times the critical concentration of calcium oxalate in urine. Other factors, known to favour crystallogenesis were modified during the same period: low urinary output, relative hypercalciuria and uraturia and hypomagnesuria. Thus, conditions for intraluminal precipitation of calcium oxalate were present post operatively. We suggest the use of a xanthine oxidase inhibitor to prevent hyperoxaluria.

[Value of potassium canrenoate in the prevention of arrhythmia during the acute phase of myocardial infarction]. / Intérêt du canrénoate de potassium dans la prévention des troubles du rythme à la phase aiguë de l'infarctus du myocarde.

This study was based on a series of 486 patients with acute myocardial infarction. All were treated with heparin and nitrite derivatives. 320 patients received 600 mg/24 h Potassium Canrenoate for 5 days (long duration); 90 patients received 1000 mg of Potassium for the first 36 hours only. 76 patients did not receive the drug and served as controls. The biochemical changes due to Potassium Canrenoate are discussed with special emphasis on the serum and intraerythrocytic potassium levels. The antiarrhythmic action of the potassium was assessed directly (the number of ventricular extra systoles decreased significantly) and indirectly (the amount of antiarrhythmic therapy required in association was three times less in patients treated by Potassium Canrenoate). The mortality rate changed from 17 to 12%. The beneficial effect of Potassium Canrenoate is attributed to the maintenance or the restoration normal potassium levels of ischaemic myocardial tissue.

[Identification of proteins by immunochemical methods after electrophoretic runs on different supports (author's transl)]. / Méthodes immunochimiques d'identification de protéines après migration électrophorétique sur différents supports

The determination of the location of serum proteins after electrophoresis on various supports and after immunoelectrophoresis has been achieved by immunochemical methods with specific antisera. The present study describes the technique, gives details of various identified fractions and presents some figures. The method allows us to study the constitution of the "beta-gamma block" observed on paper and acetate supports after electrophoresis of cirrhotic sera and to superimpose the patterns of apparently distinct fractions on polyacrylamide gel.