Exclusion of the GNAS locus in PHP‐Ib patients with broad GNAS methylation changes: Evidence for an autosomal recessive form of PHP‐Ib?

Most patients with autosomal dominant pseudohypoparathyroidism type Ib (AD‐PHP‐Ib) carry maternally inherited microdeletions upstream of GNAS that are associated with loss of methylation restricted to GNAS exon A/B. Only few AD‐PHP‐Ib patients carry microdeletions within GNAS that are associated with loss of all maternal methylation imprints. These epigenetic changes are often indistinguishable from those observed in patients affected by an apparently sporadic PHP‐Ib form that has not yet been defined genetically. We have now investigated six female patients affected by PHP‐Ib (four unrelated and two sisters) with complete or almost complete loss of GNAS methylation, whose healthy children (11 in total) showed no epigenetic changes at this locus. Analysis of several microsatellite markers throughout the 20q13 region made it unlikely that PHP‐Ib is caused in these patients by large deletions involving GNAS or by paternal uniparental isodisomy or heterodisomy of chromosome 20 (patUPD20). Microsatellite and single‐nucleotide variation (SNV) data revealed that the two affected sisters share their maternally inherited GNAS alleles with unaffected relatives that lack evidence for abnormal GNAS methylation, thus excluding linkage to this locus. Consistent with these findings, healthy children of two unrelated sporadic PHP‐Ib patients had inherited different maternal GNAS alleles, also arguing against linkage to this locus. Based on our data, it appears plausible that some forms of PHP‐Ib are caused by homozygous or compound heterozygous mutation(s) in an unknown gene involved in establishing or maintaining GNAS methylation. © 2011 American Society for Bone and Mineral Research     

A cross-sectional study evaluating the knowledge and beliefs about,and the use of antibiotics amongst Malaysian university students

Background: The introduction of antibiotics into modern medicine has changed clinical care by saving millions of lives. However, misuse of antibiotics has led to their benefits being overshadowed by the development of antimicrobial resistance.

Aims of Study: This study aimed to assess university students’ knowledge and beliefs about and their use of antibiotics.

Methods: This cross-sectional study was conducted among 674 medical and non-medical students of the National Defence University of Malaysia, using universal and convenience sampling methods. The data was collected using a validated questionnaire and analyzed using IBM SPSS 24, and the MANOVA test and Logistic Regression were used to explore the associated factors.

Results: More than half of the respondents’ knowledge was low and their health beliefs outdated. Age, race and program were significantly associated with up-to-date knowledge and beliefs about antibiotic use, factors associated with finishing a course of antibiotics were studying medicine, personal health, and ethnicity. The significant factors associated with antibiotic self-prescribing were beliefs having been prescribed antibiotics during the last one year, and trusting the doctors who did not prescribe antibiotics.

Conclusion: This study has identified a concerning low knowledge about antibiotics amongst some Malaysian university students, reflected in use of un-prescribed antibiotics and a lack of adherence to treatment. There is a need for educational interventions for students regarding antibiotic usage and resistance issues.     

Preparation and Thermal Characterization of Annealed Gold Coated Porous Silicon

Porous silicon (PSi) layers were formed on a p-type Si wafer. Six samples were anodised electrically with a 30 mA/cm² fixed current density for different etching times. The samples were coated with a 50–60 nm gold layer and annealed at different temperatures under Ar flow. The morphology of the layers, before and after annealing, formed by this method was investigated by scanning electron microscopy (SEM). Photoacoustic spectroscopy (PAS) measurements were carried out to measure the thermal diffusivity (TD) of the PSi and Au/PSi samples. For the Au/PSi samples, the thermal diffusivity was measured before and after annealing to study the effect of annealing. Also to study the aging effect, a comparison was made between freshly annealed samples and samples 30 days after annealing.