[Inter-institute variations in International Normalized Ratio and thrombotest].

Oral anticoagulant therapy is effective for reducing the risk of thromboembolic events in patients with atrial fibrillation or other heart diseases. However, the intensity of oral anticoagulation therapy required in high risk patients, especially in Japanese patients, to achieve the best balance between the prevention of thromboembolic events and bleeding complications remains unclear. The multicenter study of Toyama Warfarin Rational Dosage (TOWARD) was started in 1996 to determine the optimal level of anticoagulant therapy. This study investigated the relationship between values of thrombotest (TT) and International Normalized Ratio (INR) measured from the same samples to clarify inter-institute variations. The relationship between TT and INR was not linear but hyperbolic. Changes of INR to TT are relatively small in the TT range of more than 20% as compared with the range of 20% or less. There were considerable inter-institute variations of TT, and the coefficient of variation (CV) was 0.16 and 0.24 in the low level and high level anticoagulation samples, respectively. However, the variations became significantly small when the same reference was used. The CV of INR was 0.12 and 0.08 in the high level and low level anticoagulation samples, respectively, and very similar with the control samples without anticoagulation (0.11). The variation was small when INR was obtained from the international sensitivity index (ISI) of thromboplastin less than 1.5. TT is widely used for monitoring oral anticoagulant therapy in Japan, and is an excellent system with little inter-institute variation when a standard reference is offered. Since INR has been established as an international monitoring system, the use of INR measured with thromboplastin of small ISI is recommended for monitoring.

Molecular cloning of rat leukemia inhibitory factor receptor alpha-chain gene and its expression during pregnancy.

Leukemia inhibitory factor (LIF) is a secreted glycoprotein and a pluripotent growth factor that acts on diverse cell systems. LIF transmits its effects via binding to transmembrane receptors, of which both high- and low-affinity forms have been identified. In this study, we analyzed the structure and expression of rat LIF receptor alpha-chain (rLIFR alpha) cDNA. A full-length clone of the cDNA encoding the membrane-bound form of rLIFR alpha protein was prepared by a combination of LA-PCR and 5' RACE using DNA reverse-transcribed from total RNA isolated from the livers of day-12 and day-14 pregnant rats as templates. The nucleotide sequence of a full-length clone was determined and further confirmed by analysis of shorter DNA fragment prepared by PCR using pfu polymerase. The gene for rLIFR alpha encodes a 1093 amino acid residue protein. The rLIFR alpha protein shows a high degree of similarity to mouse and human LIF receptor alpha-chain protein (89% and 76% amino acid sequence identities, respectively). Only one molecular species of mRNA for the rLIFR alpha gene was detected in the liver and placenta. rLIFR alpha was expressed in liver of both non-pregnant and pregnant rats. The level of mRNA for the rLIFR alpha gene in placenta was maximum on day 16 of pregnancy.

Chromatographic profiles of urinary isoenzymes in healthy children.

Urinary excretion of alkaline phosphatase, gamma-glutamyltransferase and lactate dehydrogenase was studied in a carefully selected group of 155 healthy children, 83 females and 72 males. Enzyme activity was assayed in randomly collected urine samples after gel filtration of the urine specimens. On chromatograms, urinary enzymes of alkaline phosphatase, gamma-glutamyltransferase and lactate dehydrogenase were separated into 4, 2 and 5 isoenzymes, respectively. Mean values of alkaline phosphatase, gamma-glutamyltransferase and lactate dehydrogenase activity were 4.59, 21.6 and 10.0 U/g creatinine. There were no sex-related differences besides lactate dehydrogenase which showed a higher excretion in females than in males. The excretion of urinary enzymes clearly decreased with increasing age.

Automated separation and measurement of urinary isoenzymes and protein by ion-exchange liquid chromatography.

This paper deals with a totally automated detection system for the assay of urinary isoenzymes and protein using high-performance liquid chromatography with a continuous post-column detection system. We attempted to determine the distribution of three enzymes in urine samples from a healthy child and in tissue extracts of rabbits. Alkaline phosphatase, gamma-glutamyltransferase and lactate dehydrogenase isoenzymes were each separated into six peaks. In comparison with the previous methods, this procedure provides better precision and accuracy, and it is sufficiently sensitive to allow the analysis without preconcentration of urine samples.

Rapid differentiation between glomerular and tubular proteinurias by high-performance liquid chromatography.

This study regards the urinary protein of patients with renal diseases. Analysis was done by high-performance ion-exchange chromatography (HPIEC). In patients with steroid responsive nephrotic syndrome, the urinary proteins could be separated into about 10 peaks by HPIEC, whereas in the tubular dysfunction about 15 peaks were obtained. Main peaks obtained by HPIEC were identified by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and immunochemical methods. HPIEC is an easy, reliable and rapid method for the estimation of glomerular and tubular proteinurias patterns, and it seems to be a good indicator of the selectivity of glomerular proteinuria. So, we recommend HPIEC for routine use in the clinical investigation of proteinuria.