Differential association of juvenile and adult systemic lupus erythematosus with genetic variants of oestrogen receptors alpha and beta.

Oestrogens acting via nuclear receptors (encoded by ESR1 or ESR2) are important for pathogenesis of systemic lupus erythematosus (SLE). rs2234693 and rs4986938 are two single nucleotide polymorphisms (SNPs) whose C and A variants increase transcription of ESR1 and ESR2, respectively. The T allele of rs2234693 was associated with early onset SLE, whereas the role of rs4986938 in SLE was not reported. Our aim was to examine the role of rs2234693 and rs4986938 in conferring susceptibility to juvenile and adult SLE (jSLE and aSLE). Genotype distribution of both SNPs was analysed in 84 jSLE, 112 aSLE patients and 1001 controls. Allele C of rs2234693 was associated with jSLE (OR = 1.87, p = 0.006, p(corrected) = 0.02), whereas allele A of rs4986938 showed an association with aSLE (OR = 1.46, p = 0.008, p(corrected) = 0.03). In jSLE, rs2234693 C had lower frequency in patients with central nervous system involvement (OR = 0.39, p = 0.005, p(corrected) = 0.04) and showed a trend for increase among males, patients with renal involvement and those without DR2/3 (p < 0.05, p(corrected) > 0.05). Whereas our results are consistent with a role of ESR1 variation in jSLE, more studies are needed since the direction of association was the opposite of that reported previously. The association between rs4986938 (ESR2) and aSLE is a novel finding, consistent with our recent report associating this variant with Graves' disease.

Spin-orbit ab initio study of alkyl halide dissociation via electronic curve crossing.

An ab initio study of the role of electronic curve crossing in the photodissociation dynamics of the alkyl halides is presented. Recent experimental studies show that curve crossing plays a deterministic role in deciding the channel of dissociation. Coupled repulsive potential energy curves of the low-lying n-sigma(*) states are studied including spin-orbit and relativistic effects. Basis set including effect of core correlation is used. Ab initio vertical excitation spectra of CH(3)I and CF(3)I are in agreement with the experimental observation. The curve crossing region is around 2.371 A for CH(3)I and CF(3)I. The potential curves of the repulsive excited states have larger slope for CF(3)I, suggesting a higher velocity and decreased intersystem crossing probability on fluorination. We also report the potential curves and the region of curve crossing for CH(3)Br and CH(3)Cl.

Retention and separation studies of cholesterol and bile acids using thermostated thin-layer chromatography.

The influence of temperature on retention and separation of cholesterol and bile acids, using reversed-phase thin-layer chromatography, was studied. As mobile phases methanol-water mixtures of various compositions were used. Chromatographic experiments were performed using vapor-saturated chambers at temperatures ranging from 5 to 60 degrees C. A linear relationship between R(M) values and temperature (1/T) as well as mobile phase composition was observed. The elution order of steroids under the conditions investigated was discussed. Each chromatogram was evaluated using simple optimization parameters and the best chromatographic conditions for the separation of multicomponent samples were chosen.

The influence of temperature on the multiple separation of estrogenic steroids using mobile phases modified with beta-cyclodextrin in high-performance liquid chromatography.

The effect of temperature on the retention and multiple separation of six estrogenic steroids in reversed-phase liquid chromatography has been studied. Capacity factors (k') of estriol, 17 beta-estradiol, 17 alpha-estradiol, d-equilenin, equilin and estrone were measured using mobile phase modified with different concentrations of beta-cyclodextrin (from 0-16 mM), a fixed solvent composition (acetonitrile-water) and a wide range of column temperatures (from 5 to 80 degrees C). The plots of capacity factors vs. reciprocal of absolute temperature are nonlinear in each case when mobile phase modified with beta-cyclodextrin was used. Particularly strong nonlinearity was observed at lower temperature and at higher beta-cyclodextrin concentration. The complex chromatograms were evaluated using optimization parameters such as capacity factor of the last-eluted peak (k'max), the smallest resolution between adjacent peaks (Rs,min) and relative resolution product (r). The results presented describe precisely the role of temperature in high-performance liquid chromatography systems in which mobile phases modified with cyclodextrin were used. Moreover, the elution order of estrogenic steroids on modified and unmodified mobile phases has been discussed.

The influence of temperature on the high performance liquid chromatographic separation of steroids using mobile phases modified with beta-cyclodextrin.

The effect of temperature on the retention and multiple separation of hydrocortisone, testosterone, 17 alpha-methyltestosterone, prednisone, cortisone and 17 alpha-hydroxyprogesterone in reversed-phase liquid chromatography has been studied. Capacity factors (k') of the steroids were measured using a mobile phase modified with different concentrations of beta-cyclodextrin (from 0-16 mM), a fixed solvent composition (acetonitrile-water) and a wide range of column temperatures (from 5-80 degrees C). The plots of capacity factors vs. reciprocal of absolute temperature are nonlinear in every case when mobile phase modified with beta-cyclodextrin was used. Particularly strong nonlinearity was observed at lower temperature and at higher beta-cyclodextrin concentration. The complex chromatograms were evaluated using optimization parameters such as capacity factor of the last-eluted peak (k'max), the smallest resolution between adjacent peaks (Rs; min) and relative resolution product (r). The results presented describe precisely the role of temperature in high performance liquid chromatography systems in which mobile phases modified with cyclodextrin were used.