Clinical correlation of neuropsychological tests with 1H magnetic resonance spectroscopy in hepatic encephalopathy

The mortality from coronary and cerebrovascular diseases is higher in Finnmark County than in other Norwegian counties. In a population-based cohort study, we compared the incidence of myocardial infarction, stroke, and diabetes mellitus in different ethnic groups in Finnmark. A total of 10,622 subjects of Norse, Sami, and Finnish origin were followed for 14 years. During approximately 150,000 person-years, we identified 509 and 84 cases of myocardial infarction, 107 and 75 cases of stroke, and 96 and 73 cases of clinical diabetes mellitus among men and women, respectively. A total of 533 men and 199 women died. Norse subjects born outside of Finnmark had the most favorable risk factor levels and, in general, the lowest incidence of disease. Men of Finnish origin had a higher incidence rate of all endpoints than other men, and Finnish women had a higher incidence rate of myocardial infarction than other women. Sami women were more obese but did not have a higher diabetes mellitus incidence than other women. After adjustment for major cardiovascular risk factors and height, most ethnic differences were attenuated.     

Antigenic and genomic diversity of human rotavirus VP4 in two consecutive epidemic seasons in Mexico

In the present investigation we characterized the antigenic diversity of the VP4 and VP7 proteins in 309 and 261 human rotavirus strains isolated during two consecutive epidemic seasons, respectively, in three different regions of Mexico. G3 was found to be the prevalent VP7 serotype during the first year, being superseded by serotype G1 strains during the second season. To antigenically characterize the VP4 protein of the strains isolated, we used five neutralizing monoclonal antibodies (MAbs) which showed specificity for VP4 serotypes P1A, P1B, and P2 in earlier studies. Eight different patterns of reactivity with these MAbs were found, and the prevalence of three of these patterns varied from one season to the next. The P genotype of a subset of 52 samples was determined by PCR. Among the strains characterized as genotype P[4] and P[8] there were three and five different VP4 MAb reactivity patterns, respectively, indicating that the diversity of neutralization epitopes in VP4 is greater than that previously appreciated by the genomic typing methods.     

HIV infection and AIDS among drug injectors at Rio de Janeiro: perspectives and unanswered questions

Determination of the presence and characterization of oestrogen receptors (ERs) in subcutaneous and internal fat depots were performed and compared with ERs in the uterus using ligand binding and immunological techniques. Successful and consistent measurement of ERs in ovine adipose tissue could only be accomplished in animals depleted of endogenous sex steroids by combined ovariectomy and adrenalectomy. Scatchard, sucrose gradient and Western blot analyses all confirmed the presence of ERs in the cytosolic fractions of various adipose and uterine tissues from ovariectomized-adrenalectomized ewes. The approximate Kd values of 0.1-0.4 nmol/l for oestradiol binding in cytosolic fractions of gluteal, omental and perirenal adipose tissues were similar to the expected high affinity binding of Kd 0.35 nmol/l observed in uterine tissue. The binding was specific for oestrogens, as unlabelled diethylstilboestrol and oestradiol effectively competed with labelled hormone for receptor sites and progesterone, R5020, testosterone and dexamethasone all failed to compete. Mean (+/- S.E.M.) concentrations of ERs, expressed as fmol specific binding sites per mg protein, were much lower (P < 0.05) in adipose tissues than in uterine tissue (975 +/- 33). However, the content of ERs was greater (P < 0.05) in subcutaneous gluteal fat (11.5 +/- 0.8) than in the internal omental or perirenal fat (5 +/- 0.6) depots. ERs from adipose and uterine tissues both migrated as moieties of 8S on 5-20% sucrose gradients. Western blot analysis of ERs from uterine and adipose tissues in the presence of protease inhibitors demonstrated an immunostaining band with a molecular mass of 67 kDa.(ABSTRACT TRUNCATED AT 250 WORDS)     

13-cis-retinoic acid in silicone-fluorosilicone copolymer oil in a rabbit model of proliferative vitreoretinopathy

The purpose of this study was to evaluate the effect of 13-cis-Retinoic Acid (RA) in Silicone-Fluorosilicone Copolymer Oil (SiFO) in a rabbit model of proliferative vitreoretinopathy (PVR). Rabbits underwent gas-compression vitrectomy. During gas-SiFO exchange, group 1 was injected with 1 ml (10 microg ml-1) 13-cis-RA in SiFO, group 2 with 1.5 ml (9 microg 1.5 ml-1) all-trans-RA in SiFO, group 3 with 1 ml SiFO alone, and group 4 with balanced salt solution (BSS). Groups 1-4 were also injected with 0.1 ml suspension of fibroblasts (75,000 0.1 ml-1) and 0.05 ml platelet rich plasma (70,000 0.1 ml-1), and were observed for 4 weeks. Group 5 was injected with SiFO alone, group 6 with 1 ml (10 microg ml-1) 13-cis-RA in SiFO, group 7 with 1.5 ml (9 microg 1.5 ml-1) all-trans-RA in SiFO, and group 8 with BSS. After 4 weeks, groups 5-7 underwent SiFO-BSS exchange. ERG and histopathology were performed to test for retinal toxicity in groups 5-8. The incidence of traction retinal detachment at 4 weeks was: group 1, 42.9%; group 2, 36.4%; group 3, 87.5%; and group 4, 88.9%. A significant difference in the incidence of PVR was noted between treated eyes (groups 1 and 2) and control eyes (groups 3 and 4) at 2, 3, and 4 weeks (P<0.05). No significant difference in the incidence of PVR was found between groups 1 and 2 during the same observation periods. ERG and histopathological studies showed no differences between the treated and the control fellow eyes (group 5-7) after 4 weeks. 13-cis-RA in SiFO (10 microg ml-1) is as effective as all-trans-RA in SiFO (9 microg 1.5 ml-1) in controlling the incidence of PVR when used for short term retinal tamponade and does not appear to be associated with retinal toxicity.     

酸洗工艺段优化改造分析

介绍了唐钢冷轧薄板厂对连续酸洗线工艺段优化改造的过程,分析了改造的实际成效,取得了较好效果.     

Fumonisin B1 consumption by rats causes reversible, dose-dependent increases in urinary sphinganine and sphingosine

Fumonisin B1 (FB1) is a frequently encountered mycotoxin that inhibits ceramide synthase, the enzyme that acylates sphinganine, sphingosine and other "sphingoid" bases. Exposure of rats, rabbits, pigs and nonhuman primates to fumonisin-contaminated feed elevates sphingoid base amounts in urine; therefore, this study examined the time course and reversibility of these changes. When an AIN-76 diet supplemented with >/=5 microg FB1/g was fed to male Sprague-Dawley rats, there was a significant increase in sphinganine (ca. 50-fold in urine from rats fed 50 microg FB1/g diet) and smaller changes in sphingosine within 5 to 7 d, compared to rats fed the same diet without FB1. No change occurred in sphingoid bases upon feeding 1 microg FB1/g for up to 60 d. When rats were fed FB1 (10 microg FB1/g diet for 10 d), then changed to the same diet minus FB1, urinary sphingoid bases returned to normal within 10 d. However, if the rats were fed 10 microg FB1/g for 10 d, then changed to 1 microg FB1/g, the amounts of sphingoid bases in urine were the same as for rats that were continuously fed 10 microg FB1/g. These results establish that consumption of FB1 causes dose-dependent and reversible elevations in the amounts of urinary sphingoid bases. The finding that 1 microg FB1/g (which does not, alone, alter urinary sphingoid bases) will sustain the elevation caused by previous exposure to 10 microg FB1/g raises the possibility that even low levels of fumonisins could be deleterious when an animal is occasionally exposed to higher amounts.     

Regeneration and luminescence of aequorin in Chinese hamster ovary cells transformed with cDNA for apoaequorin

Aequorin, a photoprotein which is regenerated from apoaequorin by incubation with coelenterazine, emits light when it binds Ca2+. The aim of this study was to determine if apoaequorin could be used in adherent mammalian cells for measuring cytosolic Ca2+, and imaging Ca2+, at the single cell level. Chinese hamster ovary (CHO-K1) cells were stably transformed with apoaequorin cDNA and expressed apoaequorin while attached to the culture dishes. Maximal luminescence intensity was obtained when 0.5 x 10(6) cells/ml were grown and incubated with 2.5 microM coelenterazine for 4 hr at 20 degrees C. Ca2+ mobilizing agents (ionomycin and maitotoxin) induced luminescence in CHO-K1 transformed cells. However, imaging of light emission from single cells proved to be unsuccessful. Ca2+ could be readily measured in the adherent CHO-K1 cells, but imaging was not possible at the single cell level.     

Proton transfer in the mechanism of triosephosphate isomerase

Triosephosphate isomerase (TIM) catalyzes the reversible interconversion of dihydroxyacetone phosphate (DHAP) and glyceraldehyde 3-phosphate (GAP), with Glu-165 removing the pro-R proton from C1 of DHAP and neutral His-95 polarizing the carbonyl group of the substrate. During the TIM reaction, approximately 2% of the pro-R tritium from C1 of DHAP is conserved and appears at C2 of GAP [Nickbarg, E. B., and Knowles, J. R. (1988) Biochemistry 27, 5939]. In the "classical" mechanism, 98% of the pro-R tritium exchanges with solvent from Glu-165 at the intermediate state and the remaining 2% is transferred by Glu-165 to C2 of the same substrate molecule. This intramolecular transfer of tritium is therefore predicted to be independent of DHAP concentration. On the basis of NMR detection of a strong hydrogen bond between Glu-165 and the 1-OH of an analogue of the enediol intermediate [Harris, T. K., Abeygunawardana, C., and Mildvan, A. S. (1997) Biochemistry 36, 14661], we have suggested a "criss-cross" mechanism for TIM in which Glu-165 transfers a proton from C1 of DHAP to O2 of the enediol, and subsequently from O1 of the enediol to C2 of the product GAP. Since the pro-R proton is transferred to O2 instead of C2 in the criss-cross mechanism, no intramolecular transfer of label from substrate to product would be expected to occur. However, intermolecular transfer of label could occur if the label exchanges from O2 into a group on the protein and is transferred to GAP in subsequent turnovers. The extent of intermolecular tritium transfer in the criss-cross mechanism would be predicted to be dependent on DHAP concentration. The extent of tritium transfer was studied as a function of initial DHAP concentration using DHAP highly tritiated at the pro-R position. At 50% conversion to GAP, triphasic tritium transfer behavior was found. For phase 1, between 0.03 and 0.3 mM DHAP, a constant extent of tritium transfer of 1.19 +/- 0.03% occurred. For phase 2, between 0.3 and 1.0 mM DHAP, the extent of transfer progressively increased as a function of DHAP concentration to 2.17 +/- 0.15%. For phase 3, between 1.0 and 7.0 mM DHAP, the extent of transfer slightly decreased to 1.68 +/- 0.17%. In a direct test for intermolecular isotope transfer, doubly labeled [1(R)-D, 13C3]DHAP and 13C-depleted [1(R)-H,12C3]DHAP were synthesized, mixed in equal amounts, and incubated at 1 mM total DHAP with TIM, GAP dehydrogenase, NAD+, and arsenate until 50% conversion to 3-phosphoglycerate occurred. Electrospray ionization mass spectral analysis of the stable 3-phosphoglycerate product detected an extent of 1.4 +/- 0.4% of intramolecular D transfer from [13C3]DHAP to the 13C3 product, but no intermolecular transfer (相似文献