The correlation between oxygen saturation indices and the standard obstructive sleep apnea severity.

OBJECTIVE: Currently accepted guidelines categorize obstructive sleep apnea (OSA) severity according to the Apnea-Hypopnea Index (AHI). However, it is unclear how to best define OSA severity. The present study sought to evaluate the concurrent validity of the widely accepted AHI by correlating it with various oxygen saturation (SpO2) and polysomnographic parameters. METHODS: The study utilized the data of a previous survey concerning the prevalence of OSA among a middle-aged Saudi population (n = 2682). Among the 346 individuals who underwent polysomnography, 178 had total sleep times of at least 240 min with rapid eye movement (REM) sleep and were included in the study. The standard classification of OSA severity was compared with different SpO2 and polysomnographic parameters. RESULTS: The study found that there were correlations between the standard OSA severity based on AHI severity classification and different SpO2 and polysomnographic parameters, including the desaturation index (DI), the sum of all desaturations, desaturation below 90%, the average duration of respiratory events, and indices of total arousals and respiratory arousals. All of these parameters correlated directly with OSA severity classification (P < 0.001 for each). However, REM sleep duration and SpO2 nadir were inversely correlated with OSA severity (P < 0.003 and < 0.001, respectively). In addition, only the DI, SpO2 nadir, and respiratory arousal index were predictors of OSA severity, as determined through a multiple logistic regression analysis. CONCLUSION: Our findings support the clinical reliability of the currently used standard classification of OSA severity based on the AHI.

Identification and manipulation of the pleuromutilin gene cluster from Clitopilus passeckerianus for increased rapid antibiotic production.

Semi-synthetic derivatives of the tricyclic diterpene antibiotic pleuromutilin from the basidiomycete Clitopilus passeckerianus are important in combatting bacterial infections in human and veterinary medicine. These compounds belong to the only new class of antibiotics for human applications, with novel mode of action and lack of cross-resistance, representing a class with great potential. Basidiomycete fungi, being dikaryotic, are not generally amenable to strain improvement. We report identification of the seven-gene pleuromutilin gene cluster and verify that using various targeted approaches aimed at increasing antibiotic production in C. passeckerianus, no improvement in yield was achieved. The seven-gene pleuromutilin cluster was reconstructed within Aspergillus oryzae giving production of pleuromutilin in an ascomycete, with a significant increase (2106%) in production. This is the first gene cluster from a basidiomycete to be successfully expressed in an ascomycete, and paves the way for the exploitation of a metabolically rich but traditionally overlooked group of fungi.

Validity of the Pittsburgh Sleep Quality Index in Indian University Students.

OBJECTIVES: Despite the demonstrated utility of the Pittsburgh Sleep Quality Index (PSQI) in various demographic groups, it has never been validated in a sample of Indian subjects. To extend and confirm the PSQI's applicability for South Asian subjects, this preliminary study aimed to assess its psychometric and diagnostic validity in a sample of university students. METHODS: Forty-seven male students were recruited from Jamia Millia Islamia, a public central university in New Delhi, India. The mean age of the students was 23.4±3.9 years, and they had a mean body mass index (BMI) of 23.3±3.3kg/m(2). The PSQI was administered to all subjects and overnight polysomnographic testing was carried out as a concurrent validation measure. RESULTS: Cronbach's alpha for the questionnaire was found to be 0.736. Internal homogeneity was high, with the majority of correlations between questionnaire component scores and the summed global score being significant (p<0.010). Criterion validity-correlations between the PSQI global score and polysomnography (PSG) measures were low. However, the questionnaire component scores and the related polysomnographic measures did show some significant relationships. The optimal cut-off scores for distinguishing students with/without sleep problems was >6 and was generated using receiver operating characteristic curve analysis. The area under the curve, sensitivity, specificity, positive and negative likelihood ratios at the cut-off score were 0.838 (p<0.0001), 75.0%, 88.9%, 6.75, and 0.280, respectively. CONCLUSION: The study found evidence that the PSQI had internal consistency, internal homogeneity, and diagnostic characteristics that compared well with PSG among a sample of young adult male students in India. This supports the applicability and certain aspects of the validity of the PSQI in the population.