Association of the ENPP1 rs997509 polymorphism with obesity in South African mixed ancestry learners

BACKGROUND

The Ectonucleotide Pyrophosphatase Phosphodiesterasel (ENPP1) polymorphisms have been associated with metabolic traits. There is no data on the effect of ENPP1 in South African children or adults.

OBJECTIVE

To investigate the role of K121Q (rs1044498), rs997509 and rs9402349 in obesity and other components of the metabolic syndrome.

DESIGN

A case-control study.

SUBJECTS

Sixty four obese and 64 lean mixed ancestry learners.

SETTING

Western Cape, South Africa.

MAIN OUTCOME MEASURE

The ENPP1 rs997509T allele is independently associated with obesity in children of mixed ancestry from South Africa.

RESULTS

The T allele frequency of the rs997509 differed significantly between obese and controls, p=0.0100 and increased the risk of being obese, p = 0.0238. Furthermore, the estimated effect of the T allele was an increase of 8.6 cm in waist circumference, 10.2 kg in weight and a corresponding 4.9 kg/m2 in BMI. Individuals carrying both the 121Q and the T allele of rs997509 were more associated with obesity (odds ratio = 3.85, 95% CI: 1.13 to 13.09) whilst those carrying the C allele of rs997509 in the presence of 121Q were likely to be lean with odds ratio of obesity 0.41 (95% CI: 0.19 to 0.87).

CONCLUSION

Our findings suggest that ENPP1 polymorphisms may contribute to different metabolic characteristics, all of which are associated with insulin resistance in mixed ancestry children of South Africa. However, a larger study is required to confirm findings of this study.

Assessment of an Interferon-gamma release assay for the diagnosis of latent tuberculosis infection in haemodialysis patient

BACKGROUND

The accurate diagnosis of latent tuberculosis infection (LTBI) in haemodialysis patients remains elusive. Impaired immune function associated with chronic kidney failure causes a high number of anergic tuberculin skin tests (TST). Interferon-gamma (INF-gamma) release assays (IGRAs) measuring the INF-gamma secretion of tuberculosis specific T-cells have several advantages over the TST but their significance in dialysis patients is currently uncertain.

METHODS

This study examines the test-performances of the QuantiFERON Gold InTube (QFT-GIT) in a cohort of 39 haemodialysis (HD) patients and 52 healthy individuals.

RESULTS

INF-gamma secretion in HD patients was significantly lower than in healthy controls, however, mitogen-anergic QFT-GIT results were only found in 2.5% of HD-patients. INF-gamma secretion was independent of duration of HD treatment, dialysis quality and nutritional status. The QFT-GIT showed a closer association with TB risk factors as a proxy for past exposure to TB than the TST.

CONCLUSIONS

We conclude that the QFT-GIT is a valid alternative to the TST. Together with the survey of TB risk factors, it may help to diagnose LTBI more accurately in HD-patients.

Vascular cognitive syndromes: relation to stroke etiology and topography

BACKGROUND

Cognitive syndromes (CS) after stroke may be important to measure and monitor for management and emerging therapies.

AIM

To describe the spectrum and frequency of CSs in the first month after stroke and to relate these to stroke etiology and topography.

METHODS

A validated cognitive examination was administered during the first month of stroke presentation and analyzed according to five large-scale networks for cognition and correlated with neuropsychological tests. A multivariate analysis was performed to determine association of CSs with etiology (TOAST classification), topography and neurological deficit by National Institute of Health Stroke Score (NIHSS).

RESULTS

Of a total of 2105 patients, one or more patients with CS was present in 1569/1796 (87%) stroke patients vs 112/309 (36%, P < or = 0.001) transient ischemic attack (TIA) patients. The frequency of frontal network syndromes (FNS) was 908/1796 (51%), left hemisphere network (LH) syndromes 646/1796 (36%), right hemisphere (RH) network syndromes 275/1796 (15.3%), occipitotemporal network (OT) syndromes 107/1796 (6%), hippocampal limbic (HL) network syndromes 397/1796 (22%) and miscellaneous (M) syndromes 481/1796 (27%). Stroke etiology and their signature CS by multivariate analyses revealed significant associations for LH with cardioembolism (OR 1.61, P = 0.0029), FNS and 'other' etiology (OR 1.96, P < or = 0.0001) and HL also for 'other' etiology (OR 1.57, P = 0.0026). Coma (OR 2.95, P < or = 0.0001) and encephalopathy (OR 2.82, P < or = 0.0001) were both associated significantly with hemorrhage. A left hemisphere lesion was associated with LH CSs (OR 9.26, P < or = 0.0001). An FNS was associated with frontal lesions (OR 5.19, <0.0001) as well as subcortical lesions (OR 1.91, P < or = 0.0001). The M group of CS was associated with subtentorial (OR 1.86, P = 0.0283) and right hemisphere lesions (OR 2.47, P < or = 0.0001). The LH and RH syndromes had the highest NIHSS and differed significantly from all others.

CONCLUSIONS

(1) CSs are present in the vast majority of stroke patients. (2) Particular stroke etiological subtypes are associated with specific CS. (3) Certain signature CS results from lesions that relate to the major anatomical cognitive networks.

Orientation-dependent work function of in situ annealed strontium titanate

We have used energy-filtered x-ray photoelectron emission microscopy (XPEEM) and synchrotron radiation to measure the grain orientation dependence of the work function of a sintered niobium-doped strontium titanate ceramic. A significant spread in work function values is found. Grain orientation and surface reducing/oxidizing conditions are the main factors in determining the work function. Energy-filtered XPEEM looks ideally suited for analysis of other technologically interesting polycrystalline samples.

High-power quantum-dot-based semiconductor disk laser

We demonstrate multiwatt cw output power from an optically pumped quantum-dot semiconductor disk laser. Continuous-wave output power of 4.35 W with 22% slope efficiency was demonstrated at a center wavelength of 1,032 nm. This represents an increase in power of 15 times and an increase in slope efficiency of 10 times from the previously published results using Stranski-Krastanow grown quantum dots. An intracavity diamond heat spreader was used for thermal management. The maximum output power was limited by the available pump power, and no sign of thermal rollover was observed.

Detection and evaluation of initial cartilage pathology in man: A comparison between MRT, arthroscopy and near-infrared spectroscopy (NIR) in their relation to initial knee pain

BACKGROUND AND AIMS

MRI and arthroscopy are important methods in the evaluation of cartilage pathology. But frequently initial changes of cartilage in combination with chronic knee pain cannot be detected by employing these two methods. Better diagnostic tools for the detection of the early stages of osteoarthritis (OA) are required. The objective of this study was to show that near-infrared spectroscopy (NIRS) can be incorporated into routine arthroscopy to improve detection and assessment of the initial cartilage pathology. Furthermore correlations between findings in MRI, arthroscopy and NIRS in patients with initial symptoms of OA have studied.

METHODS

Patients (n=21, 12 women, 9 men, age: 15-59 years, mean 34.19 years) with knee pain lasting for at least half a year without any trauma of the knee in their history were interviewed (body weight, smoking behaviour) and clinically evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS). Also serum parameters (cholesterol, lipids) were analysed, conventional X-rays in three directions (evaluated according to Kellgren and Lawrence) and MRI (evaluation of cartilage damage according to the ICRS-score) were performed preoperatively in all patients. During subsequent arthroscopy cartilage damage was evaluated according to the ICRS-score. In addition the spectral reflection of cartilage was investigated in all knees using a special micro-glass-fiber probe in the near-infrared light region (spectral range between 1150 and 1475nm). To characterize relations between the investigated parameters the Spearman's rank correlation coefficient was used. Inter-observer variance was calculated employing the Cohens-Kappa-test.

RESULTS

MRI demonstrated a strong inter-observer variance with no significant correlations to other parameters. The same was observed for arthroscopic findings. Only NIRS showed significant correlations with three out of five KOOS subscores. Within the general parameters only smoking behaviour showed a significant correlation with two of the KOOS-scores. NIRS therefore seemed to be a sensitive diagnostic tool in detection of initial pathology in human cartilage. The additional necessary time for the spectroscopic investigation as part of the routine arthroscopy ranged between 3 and 7min (mean: 4min 18s).

CONCLUSION

Particularly for early-stage cartilage lesions (ICRS 0/I) MRI and arthroscopy have rather low predictive value. The inter-observer variance is very high (Cohens-Kappa<0.4). Correlations found between NIRS and KOOS suggest that NIRS potentially can be used for detection of initial cartilage pathology and may be helpful in the evaluation of the benefit of different medical or surgical interventions at early-stage of articular cartilage damage.

Genetic linkage map of the guppy, Poecilia reticulata, and quantitative trait loci analysis of male size and colour variation

We report construction of a genetic linkage map of the guppy genome using 790 single nucleotide polymorphism markers, integrated from six mapping crosses. The markers define 23 linkage groups (LGs), corresponding to the known haploid number of guppy chromosomes. The map, which spans a genetic length of 899 cM, includes 276 markers linked to expressed genes (expressed sequence tag), which have been used to derive broad syntenic relationships of guppy LGs with medaka chromosomes. This combined linkage map should facilitate the advancement of genetic studies for a wide variety of complex adaptive phenotypes relevant to natural and sexual selection in this species. We have used the linkage data to predict quantitative trait loci for a set of variable male traits including size and colour pattern. Contributing loci map to the sex LG for many of these traits.