Wilms' tumor suppressor gene mutations in girls with sporadic isolated steroid-resistant nephrotic syndrome.

Mutations in the Wilms' tumor suppressor gene (WT1) can lead to syndromic forms of steroid-resistant nephrotic syndrome (SRNS) such as Denys-Drash or Frasier syndrome and can cause isolated SRNS. A mutation within WT1 is a frequent cause of sporadic isolated SRNS in girls. In a worldwide cohort of girls, the rate of occurrence was 10.8%. Previous reports have indicated that in Chinese girls, the detection rate of WT1 mutations is 16.7% for early onset isolated nephrotic syndrome. The detection rate of WT1 mutations in Chinese girls with sporadic isolated SRNS is unknown. We examined WT1 mutations in 14 Chinese girls with sporadic isolated SRNS using polymerase chain reaction and direct sequencing and studied a control group of 38 boys with sporadic isolated SRNS. We identified a WT1 mutation in 1 of 14 (7.1% detection rate) Chinese girls with sporadic isolated SRNS. No mutations occurred in WT1 in the remaining 13 girls or the control group. Our investigation supports the necessity of genetic examination for mutations in WT1 in girls with sporadic isolated SRNS.

[Determination of docosahexenoic acid in human serum by capillary gas chromatography].

A reliable CGC method was developed for the determination of docosahexenoic acid (DHA) in human serum. The serum sample was acidified by adding two drops of 4.5 mol.L-1 H2SO4, and DHA was extracted from serum using ethyl acetate. The extract was evaporated to dryness under nitrogen stream. To each residue, 1 ml 1.3 mol.L-1 methanolic hydrogen chloride solution was added and the mixture was allowed to stand for 30 min in 60 degrees C water bath. After derivatization, the mixture was extracted with 1 ml of n-hexane. The solvent was evaporated under a stream of nitrogen to dryness and the residue was dissolved in 30 microliters n-hexane and subjected to capillary GC, which was equipped with a fused silica capillary column (26.3 m x 0.25 mm ID) coated with FFAP (free fatty acid phase, 0.1 micron film thickness). Tricosanoic acid was used as an internal standard. The retention time of DHA-M and internal standard was 23.41 min and 20.79 min, respectively. The minimum detection concentration of DHA in serum was 40 ng.ml-1 with a serum volume of 200 microliters and S/N value of 2. A good linear relationship between the peak area ratios and concentrations was found at the DHA concentrations ranging from 25 to 200 micrograms.ml-1. The within-day and between-day precision was 5% and 9%, respectively.

[Gas chromatographic method with EC detection to determine isosorbide-5-mononitrate (IS-5-MN) in human serum and its pharmacokinetic parameters].

A simple, sensitive and precise capillary GC-ECD method was developed for the determination of isosorbide-5-mononitrate in human serum. Pharmacokinetic parameters of the drug was obtained from the human serum level-time curve measured. Serum samples were extracted with a mixture of ethyl ether-ethyl acetate (4:1), the upper phase was collected and evaporated to about 100 microliters under a gentle nitrogen stream. Isosorbide dinitrate was used as internal standard. With a human serum sample size of 200 microliters, the detection limit of IS-5-MN was found to be about 5 ng/ml, and the absolute recovery from 74% to 85%. The within-day and between-day relative standard deviation were less than 7% and 9%, respectively. This method was applied to the pharmacokinetic studies of IS-5-MN tablets from two different sources. Two sets of t1/2 (Ke), Tmax and AUC values obtained from 8 volunteers were tested statistically and no significant difference was found.

Enhancement of mitochondrial oxidative phosphorylation capability by hypoperfusion in isolated perfused rat heart.

To define alterations in myocardial mitochondrial function due to hypoperfusion, oxidative phosphorylation was simultaneously studied in 17 control (stable perfusion pressure) rat hearts and 17 hypoperfused isolated rat hearts. Hypoperfusion for 30 minutes was achieved by a reduction in coronary perfusion pressure from 77.8 +/- 1.2 mm Hg (mean +/- SEM) to 20.2 +/- 1.8 mm Hg in the experimental group (control perfusion pressure after 30 minutes 75.6 +/- 1.2). Hypoperfusion caused a reduction in left ventricular developed pressure to 20.5 +/- 1.5 mm Hg (versus control 74.8 +/- 3.3, p less than 0.0001), a reduction of coronary flow rate to 4.9 +/- 0.3 ml/min (versus control 19.4 +/- 1.2, p less than 0.0001), and a drop in myocardial oxygen consumption to 0.06 +/- 0.005 ml O2/min (versus control 0.17 +/- 0.01, p less than 0.0001). Myocardial lactate production was increased by hypoperfusion (3.0 +/- 0.6 mumol/min) compared with controls (0.7 +/- 0.5, p less than 0.02), but myocardial creatine kinase release was similar in the hypoperfused and control groups. Hypoperfusion was associated with an augmentation of state 3 mitochondrial respiration with glutamate and malate as respiratory substrates (448.8 +/- 14.0 ng atoms O/min/mg mitochondrial protein versus controls 290.7 +/- 13.4, p less than 0.001). When rates were normalized for mitochondrial malate dehydrogenase (MDHm), state 3 respiration was still increased in hypoperfused hearts (24.1 +/- 2.1 ng atoms O/min/IU MDHm) compared with controls (15.5 +/- 1.6, p less than 0.02). The rates of dinitrophenol-uncoupled electron transport were similar to the rates of state 3 respiration in both the hypoperfused and control groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Transport of cholesterol autoxidation products in rabbit lipoproteins.

Radiolabeled pure [4-14C]cholesterol was kept at 60 degrees C under air to autoxidize for 5 weeks, after which approximately 12% cholesterol oxidation products were formed. The mixture, suspended in gelatin, was given to rabbits by gastric gavage. Rabbits were killed 4, 24, and 48 h after treatment. Cholesterol and its autoxidation products were separated by thin-layer chromatography into 5 fractions and radioactivities of each fraction were measured. Percentages of each fraction of cholesterol oxidation products and cholesterol in the original mixture before administration and in the rabbit sera after administration were similar, suggesting that the rates of absorption of cholesterol oxidation products are not significantly different from that of cholesterol. Lipoproteins were fractionated by ultracentrifugation into VLDL, LDL and HDL. Radioactivities of each fraction in lipoproteins separated by thin layer chromatography showed that fractions containing cholestane-3 beta,5 alpha,6 beta-triol, 7 alpha- and 7 beta-hydroxycholesterol and 7-ketocholesterol were more selectively transported in VLDL, whereas most of the 25-hydroxycholesterol was present in LDL. HDL contained only minute amounts of cholesterol oxidation products.