Sub-keV design for the National Ignition Facility's soft x-ray Opacity Spectrometer (OpSpec) and expansion plans for time-resolved measurements

When compared with the National Ignition Facility's (NIF) original soft x-ray opacity spectrometer, which used a convex cylindrical design, an elliptically shaped design has helped to increase the signal-to-noise ratio and eliminated nearly all reflections from alternate crystal planes. The success of the elliptical geometry in the opacity experiments has driven a new elliptical geometry crystal with a spectral range covering 520-1100 eV. When coupled with the primary elliptical geometry, which spans 1000-2100 eV, the new sub-keV elliptical geometry helps to cover the full iron L-shell and major oxygen transitions important to solar opacity experimentation. The new design has been built and tested by using a Henke x-ray source and shows the desired spectral coverage. Additional plans are underway to expand these opacity measurements into a mode of time-resolved detection, ∼1 ns gated, but considerations for the detector size and photometrics mean a crystal geometry redesign. The new low-energy geometry, including preliminary results from the NIF opacity experiments, is presented along with the expansion plans into a time-resolved platform.

Liver enzymes, the metabolic syndrome, and incident diabetes: the Mexico City diabetes study

OBJECTIVE

To test the hypothesis that enzymes conventionally associated with liver dysfunction (aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltransferase [GGT], and alkaline phosphatase) may predict diabetes.

RESEARCH DESIGN AND METHODS

From a population-based diabetes survey, we selected 1,441 men and women in whom serum enzyme levels were < or =3 SDs of the mean population value, alcohol intake was <250 g/week, and hepatitis B and C virus testing was negative. At follow-up (7 years), 94 subjects developed diabetes and 93 impaired glucose tolerance (IGT).

RESULTS

At baseline, all four enzymes were related to most of the features of the metabolic syndrome. After controlling for sex, age, adiposity/fat distribution, alcohol intake, serum lipids, and blood pressure, higher alanine aminotransferase and GGT values were significantly (P < 0.01) associated with both IGT and diabetes, whereas alkaline phosphatase was associated with diabetes only (P = 0.0004) and aspartate aminotransferase with IGT only (P = 0.0001). Raised GGT alone was associated with all the features of the metabolic syndrome. Raised GGT was a significant predictor of either IGT or diabetes (odds ratio 1.62 [95% CI 1.08-2.42] top quartile vs. lower quartiles, P < 0.02) after controlling for sex, age, adiposity/fat distribution, alcohol consumption, fasting plasma insulin and proinsulin levels, and 2-h postglucose plasma glucose concentrations.

CONCLUSIONS

Although mild elevations in liver enzymes are associated with features of the metabolic syndrome, only raised GGT is an independent predictor of deterioration of glucose tolerance to IGT or diabetes. As GGT signals oxidative stress, the association with diabetes may reflect both hepatic steatosis and enhanced oxidative stress.

Association between polymorphisms of the atrial natriuretic peptide gene and proteinuria: a population-based study

AIMS/HYPOTHESIS

In case-control studies, polymorphisms at the atrial natriuretic peptide gene (ANP) locus have been associated with presence of albuminuria in Type 1 and Type 2 diabetes. We evaluated the relationship between the ScaIand BstxI polymorphisms and albuminuria in the general population of the Mexico City Diabetes Study.

METHODS

Allele/genotype frequencies were analysed by PCR-RFLP analysis using ScaI (wild, A(2) vs mutated, A(1)) and BstxI (wild, C(708) vs mutated, T(708)) enzyme.

RESULTS

Among 1288 subjects, hypertension was present in 112 subjects, Type 2 diabetes in 191 and impaired glucose tolerance in 136; microalbuminuria was present in 464 subjects, and clinical proteinuria in 199. General frequencies were 0.93 and 0.96 for the wild alleles, and 0.07 and 0.04 for the mutated alleles, respectively for ScaI and BstxI. Frequency of A(1)was 0.08 in normoalbuminuric, 0.05 in microalbuminuric, and 0.05 in proteinuric patients (chi(2)=7.3, p=0.025). Frequency of T(708) was 0.06 in normoalbuminuric and 0.03 microalbuminuric and 0.03 in proteinuric subjects (chi(2)=8.1, p=0.017). By multivariate analysis, the associations between A(1)or T(708) allele and albuminuria were independent of age, sex, BMI, diabetes, and hypertension, (odds ratio (OR) 0.60, p=0.01, (OR) 0.51, p=0.004, respectively).

CONCLUSION/INTERPRETATION

In the general population of Mexico City, both polymorphisms of ANP are associated with albuminuria independently of hypertension, and could play a role in protecting subjects against development of albuminuria.

Simplified method for the detection of apo(a) isoforms

Apolipoprotein a, is a high molecular weight glycoproteic component of Lp(a), a molecule associated with coronary arterial disease. Apo(a) exhibits considerable size heterogeneity due to variable repetitions of the carbohydrate-containing structural unit, termed kringle. There are five different kringle forms and 10 different kringle 4 types. Apo(a) polymorphism and molecular weight depend on the number of copies of kringle 4 type 2. In this paper we describe a modified 3.75% and 6% discontinuous polyacrylamide gel system and Western-blot technique that shortness the assay time and improves the identification of apo(a) isoforms with a theoretical error of less than 1 kringle. The assay uses a standard curve prepared with five different recombinant apo(a) molecules, detected up to 50 ng of protein in Lp(a), showed a maximal resolution of 2 kringles and, with the use of third degree polynominal regression analysis, had an error of 0.01275. The inter-assay coefficient of variation was 1.7, 2, and 1.4 for the 14 K, 18 K, and 22 K phenotypes, whereas the intra-assay coefficient of variation was 0.32%, 0.18%, and 0.17%, respectively. It is possible that this modified method will diminish the number of putative null alleles so far detected in various studies, but most of all, we are certain that it can be of use in epidemiological studies due to its ease of use, speed, low cost, and enhanced number of samples that can be tested.

Insulin-induced endothelin release and vasoreactivity in hypertriglyceridemic and hypertensive rats

Insulin-elicited endothelin release in hypertriglyceridemic, hypertensive, hyperinsulinemic (HTG) rats was shown. Weanling male Wistar rats were given 30% sucrose in their drinking water for 20-24 wk. In vitro contractions of aorta and femoral arteries were elicited with 40 mM KCl. Endothelin release induced with KCl plus 50 microU/ml insulin resulted in increases in contractile responses: 41 +/- 5.9 and 57 +/- 6% for control and 65.5 +/- 6 and 95 +/- 9% for HTG aortas and femoral arteries, respectively. The endothelin ET(B)-receptor blocker BQ-788 decreased responses to KCl + insulin by 39 +/- 8 and 53 +/- 5% in control and 48 +/- 13 and 79 +/- 3.5% in HTG aortas and femoral arteries, respectively. The ET(A)-receptor antagonist PD-151242 inhibited these responses by 12 +/- 10 and 1 +/- 9% in control and by 51.5 +/- 9 and 58.5 +/- 1% in HTG aortas and femoral arteries, respectively. These results suggest that endothelin may contribute to the hypertension in this model.

[Rett's syndrome: analysis of the 1st 5 cases diagnosed in Brazil]

Five cases of patients with the Rett syndrome are reported. The criteria for this diagnosis in these cases are discussed. These are the first cases of the Rett syndrome reported in Brazil and the authors call attention to the fact that this syndrome seems to be in our country as frequent as in USA, Europe and Japan where it has been more studied.