Ginkgo biloba extract postconditioning reduces myocardial ischemia reperfusion injury.

We examined the protective effects of Ginkgo biloba extract (EGb761) postconditioning on myocardial ischemia reperfusion injury in rabbits. Four groups of 8 white rabbits were allocated to: pseudo surgery group: the left coronary was lined without blocking for 160 min after thoracotomy; ischemia and reperfusion group (IR): the left anterior descending coronary artery was blocked for 40 min and reperfused for 120 min; ischemic postconditioning group: the left anterior descending artery was ligated for 40 min, reopened for 30 s and ligated for 30 s, repeated three times, and then reperfused for 120 min; EGb761 postconditioning group (E): 100 mg/kg EGb761 was injected into a vein while the left coronary artery was opened for 1 min. The reperfusion took 120 min. Internal carotid arterial blood in each group was collected for cTnI measurement at five times: 20 min before occlusion of the left coronary artery, 20 min after left coronary artery occlusion, 40 min after left coronary artery occlusion, 1 h after myocardial reperfusion, and 2 h after myocardial reperfusion. Superoxide dismutase (SOD), malondialdehyde (MDA) in the centrifuged blood and myocardial infarction area were measured at the end of reperfusion. We found that the serum cTnI concentrations in the E group during reperfusion decreased significantly compared with those in the IR group. The infarction area was significantly lower in the E group than that in the IR group. The SOD activity in the E group was increased compared with that in the IR group; the MDA content decreased significantly in the E group compared with that in the IR group. We conclude that G. biloba extract postconditioning had myocardial protection effects by reducing the generation of oxygen-free radicals and increasing the antioxidant capacity of the myocardial cells.

Characterization of two novel homozygous missense mutations involving codon 6 and 259 of type II 3beta-hydroxysteroid dehydrogenase (3betaHSD) gene causing, respectively, nonsalt-wasting and salt-wasting 3betaHSD deficiency disorder.

We identified two homozygous missense mutations in the human type II 3beta-hydroxysteroid dehydrogenase (3/betaHSD) gene, the first in codon 6 of exon II [CTT (Leu) to TTT (Phe)] in a male infant with hyperpigmented scrotum and hypospadias, raised as a male and no apparent salt-wasting since neonatal age, and the second in codon 259 of exon IV [ACG (Thr) to ATG (Met)] in a male pseudohermaphrodite with labial scrotal folds, microphallus, chordee, and fourth degree hypospadias, raised as a female and with salt-wasting disorder since neonatal age. In vitro transient expression of mutant type II 3betaHSD complementary DNAs of L6F, T259M, as well as T259R for comparison was examined by a site-directed mutagenesis and transfection of construct into COS-1 and COS-7 cells. Northern blot analysis revealed expression of similar amounts of type II 3betaHSD messenger ribonucleic acid from the COS-1 cells transfected by L6F, T259M, T259R, and wild-type (WT) complementary DNAs. Western immunoblot analysis revealed a similar amount of L6F mutant protein compared to WT enzyme from COS-1 cells, but neither L6F from COS-7 cells nor T259M or T259R mutant protein in COS-1 or COS-7 cells was detectable. Enzyme activity in intact COS-1 cells using 1 micromol/L pregnenolone as substrate in the medium after 6 h revealed relative conversion rates of pregnenolone to progesterone of 46% by WT enzyme, 22% by L6F enzyme, and 8% by T259M enzyme and less than 4% activity by T259R enzyme. Using 1 micromol/L dehydroepiandrosterone as substrate, the relative conversion rate of dehydroepiandrosterone to androstenedione after 6 was 89% by WT enzyme, 35% by L6F enzyme, 5.1% by T259M enzyme and no activity by T259R enzyme. However, the L6F mutant 3betaHSD activity, despite its demonstration in the intact cells, was not detected in homogenates of COS-1 cells or in immunoblots of COS-7 cells, suggestive of the relatively unstable nature of this protein in vitro, possibly attributable to the decreased 3betaHSD activity. In the case of T259M and T259R mutations, consistently undetectable proteins in both COS cells despite detectable messenger ribonucleic acids indicate severely labile proteins resulting in either no or very little enzyme activity, and these data further substantiate the deleterious effect of a structural change in this predicted putative steroid-binding domain of the gene. In conclusion, the findings of the in vitro study of mutant type II 3betaHSD enzyme activities correlated with a less severe clinical phenotype of nonsalt-wasting and a lesser degree of genital ambiguity in the patient with homozygous L6F mutation compared to a more severe clinical phenotype of salt-wasting and severe degree of genital ambiguity in the patient with homozygous T259M mutation in the gene.