Analysis of the gas vesicle plasmidpNRC100 from Halobacterium halobium: Characterization of inversions, deletions, and the origin of replication

Halobacterium halobium strain NRC-1 harbors a 200-kilobase pair (kb) plasmid, pNRC100, which contains a cluster of genes that code for synthesis of buoyant gas-filled vesicles. A restriction map of pNRC100 was constructed using AflII, DraI, HindIII, and SfiI with the aid of pulsed-field agarose gel electrophoresis. The identity and approximate positions of seventeen insertion sequences (IS) in pNRC100 were determined by Southern hybridization and limited nucleotide sequence analysis across the IS element-target site junctions: ISH2, a 0.5-kb element, was found in four copies; ISH3, a 1.4-kb heterogeneous family of elements, was present in seven copies; ISH8, a 1.4-kb element, was found in five copies; and ISH50, a 1.0-kb element, was present in a single copy. Additionally, a large (35-38 kb) inverted repeat (IR) sequence was also found. Inversion isomers of pNRC100 were demonstrated by Southern hybridization analysis using two restriction enzymes, AflII and SfiI, that cut asymmetrically within the intervening small single copy (SSC) region and the large single copy (LSC) region, respectively, but not within the large IRs. No inversion isomers were observed for a deletion derivative of pNRC100 lacking one IR, which suggests that both copies are required for inversion to occur. One end of the large IRs terminated at an ISH2 element while the other end terminated at an ISH3 element. The pNRC100 derivatives had suffered deletions which removed the gas vesicle genes and flanking DNA sequences. An autonomous replicating sequence of pNRC100 was mapped to the 19-kb HindIII-C fragment by cloning it into an E. coli plasmid containing the Haloferax volcanii mevinolin-resistance (mev\sp{R}) gene, transformation of H. halobium with the resulting plasmid pNGHCMEV1, and recovery of pNGHCMEV1 DNA from mevinolin-resistance transformants (Rep\sp+). The nucleotide sequence of the replication origin was determined and found to contain a 550 bp highly A+T-rich segment and a 3,027 nucleotide open reading frame, named repH. The repH transcription start site was shown by primer extension analysis to be 17-18 nucleotides upstream of the putative start codon. The predicted RepH protein, an acidic protein of 113,442 molecular weight, showed 24.2 to 27.1% identity with the putative gene products of Hf. volcanii plasmid pHV2 and H. halobium halophage ($\phi$H)-derived plasmid p$\phi$HL. The replication origin was subjected to linker scanning mutagenesis and the results showed that repH is required for replication. (Abstract shortened by UMI.

Overnight pulse oximetry for screening of obstructive sleep apnea in at-risk adult patients in the primary care setting: prospective case series

Objective: To estimate prevalence of OSA among at risk adult patients in primary care setting. To test the correlation and agreement between overnight pulse oximetry and polysomnography (PSG). To test the OSA screening performance of overnight pulse oximetry. Design and Setting: Prospective case series involving adult Chinese patients with risk factors for OSA at a primary care clinic of Hong Kong. Methods: The prevalence and severity of OSA were established based on overnight pulse oximetry derived oxygen desaturation index (ODI). Screening performance of overnight pulse oximetry was compared directly with gold standard diagnostic test PSG. Results: Three hundred and five male and 229 female patients were recruited. Snoring (48.3%) was the top presenting symptom. Three hundred and twenty five patients (60.9%) were screened positive to have OSA. One hundred and nine patients had performed PSG, the ODI_4 and apnoea-hypopnea index (AHI) had Pearson correlation coefficient 0.71 (P<0.001). Bland and Altman plot showed good agreement. Using designation criteria of ODI_4≥5 events/hr, the sensitivity and specificity for OSA diagnosis are 94.4% and 78.9% respectively. Conclusion: The prevalence of OSA is 60.9% among adult primary care population who are at risk for OSA. Overnight pulse oximetry shows good performance as a screening tool for the screening of OSA

Characteristics of patients with erectile dysfunction in a family physician-led erectile dysfunction clinic: Retrospective case series

Objectives: 1. To examine the characteristics of patients with erectile dysfunction in a family physician led erectile dysfunction clinic; 2. To review association of chronic disease spectrum and erectile dysfunction; 3. To review initial treatment pattern and outcome. Design: Retrospective case series review. Subjects: All consecutive patients seen in a regional hospital family physician led erectile dysfunction clinic from April 2014 to March 2015. Main outcome measures: 1. The severity of erectile dysfunction, based on International Index of Erectile Function (IIEF-5). 2. The associated chronic comorbidities of patients. 3. Treatment patterns and patient outcomes. Results: One hundred and eighty three patients presented with erectile dysfunction (ED) with mean age 58.7 (range 23 to 82) years old were seen during the study period. One hundred and twenty seven patients (69.4%) had comorbidity of chronic diseases, including 50.8% had hypertension, 38.8% had diabetes mellitus and 33.9% had hyperlipidaemia. Their mean body mass index was 25.2 kg/m2, the mean blood pressure was 137.3/79.5 mm Hg (1 mm Hg = 0.133 kPa). According to IIEF-5 score, 50.3%, 30.6% and 18.6% had severe, moderate and mild erectile dysfunction respectively. The average duration of ED before seeking medical help was 3.9 years. Phosphodiesterase 5 (PDE5) inhibitors were prescribed to 119 patients (65%), and 57.1% of them achieved good response. Twenty nine patients (15.8%) were referred to other specialty for further management, including 27.6% had contraindication for PDE5 inhibitor. Conclusion: High proportion of erectile dysfunction patients had comorbitiy of chronic diseases. 57.1% of those patients receiving PDE5 inhibitors showed good response

Epidemiological study of hypertensive retinopathy in the primary care setting: Retrospective cross-sectional review of retinal photographs

Objective: The objective is to estimate the prevalence and grading of hypertensive retinopathy in the primary care setting; examine the patient characteristics associated with hypertensive retinopathy; and examine the association of hypertensive retinopathy and other hypertension complications. Methods: This is a retrospective cross-sectional study. Subjects included adult hypertensive patients with available and gradable retinal photographs. Results: Two hundred fifty-six male hypertensive patients (34.3%) and 491 female hypertensive patients (65.7%) were included. The average duration of hypertension was 7.2 years, and 49.8% and 41.2% of patients were taking one or two antihypertensive medications respectively. Among 1491 qualified retinal photographs (744 right eye and 747 left eye), 24.9%, 62.6%, and 12.5% were classified as showing normal, mild, and moderate hypertensive retinopathy respectively. The three commonest retinal signs were generalized or focal arteriolar narrowing (650 cases, 43.6%), hard exudates (168 cases, 11.3%), and opacity (copper or silver wiring) of the arteriolar wall (166 cases, 11.1%). Patients older than 61 years, having hypertension for more than 15 years, or taking three or more antihypertensive medications were significantly associated with hypertensive retinopathy (P<0.05). Conclusion: In a primary care clinic in Hong Kong, 77.1% of hypertensive patients had hypertensive retinopathy. Advanced hypertensive retinopathy was the commonest target organ damage for hypertensive patients in a primary care clinic

Striving to Avoid Inferiority and Procrastination among University Students: The Mediating Roles of Stress and Self-Control

The current study intended to examine whether the relationship between university students’ striving to avoid inferiority (SAI) and procrastination was serially mediated by stress and self-control. The sample consisted of 154 Hong Kong university students. Their levels of striving to avoid inferiority, stress, self-control, and procrastination were measured by the Striving to Avoid Inferiority Scale (SAIS), the stress subscale of the Depression Anxiety Stress Scales (DASS-21), the Short Self-Regulation Questionnaire (SSRQ), and the General Procrastination Scale (GPS), respectively. The results of structural equation modeling revealed that SAI positively predicted stress, stress negatively predicted self-control, and self-control negatively predicted procrastination. SAI did not directly predict procrastination. The results of bootstrapping analyses supported the hypotheses that the effect of stress on procrastination was mediated by self-control, the effect of SAI on self-control was mediated by stress, and more importantly, the effect of SAI on procrastination was serially mediated by stress and self-control. Further research is suggested to investigate the thoughts and feelings pertinent to procrastination and the actual duration of procrastination among university students

How tendency of striving to avoid inferiority would predict procrastination among university students in Hong Kong? A structural equation modeling approach

The current study intended to examine whether the relationship between individuals’ striving to avoid inferiority tendency and procrastination was mediated by stress and then self-control. A total of 154 Hong Kong university students completed five sets of questionnaires, including the Depression Anxiety and Stress Scale (DASS-21), the Striving to Avoid Inferiority Scale (SAIS), the Short Self-Regulation Questionnaire (SSRQ) and the General Procrastination Scale. The results of structural equation modeling revealed that striving to avoid inferiority positively predicted stress, stress negatively predicted self-control, and self-control negatively predicted procrastinating tendency. Striving to avoid inferiority did not directly predict procrastinating behaviour. Notwithstanding, the results of bootstrapping analyses supported the hypotheses that (H1) the effect of stress on procrastination was mediated by self-control, (H2) the effect of striving to avoid inferiority on self-control was mediated by stress, and more importantly, (H3) the effect of striving to avoid inferiority on procrastination was indirectly mediated by stress and self-control serially. Further research may investigate the thoughts and feelings pertinent to procrastinating behaviours and actual duration of procrastinating behaviour of the procrastinators among university students

MicroRNA-19a-PTEN Axis Is Involved in the Developmental Decline of Axon Regenerative Capacity in Retinal Ganglion Cells.

Irreversible blindness from glaucoma and optic neuropathies is attributed to retinal ganglion cells (RGCs) losing the ability to regenerate axons. While several transcription factors and proteins have demonstrated enhancement of axon regeneration after optic nerve injury, mechanisms contributing to the age-related decline in axon regenerative capacity remain elusive. In this study, we show that microRNAs are differentially expressed during RGC development and identify microRNA-19a (miR-19a) as a heterochronic marker; developmental decline of miR-19a relieves suppression of phosphatase and tensin homolog (PTEN), a key regulator of axon regeneration, and serves as a temporal indicator of decreasing axon regenerative capacity. Intravitreal injection of miR-19a promotes axon regeneration after optic nerve crush in adult mice, and it increases axon extension in RGCs isolated from aged human donors. This study uncovers a previously unrecognized involvement of the miR-19a-PTEN axis in RGC axon regeneration, and it demonstrates therapeutic potential of microRNA-mediated restoration of axon regenerative capacity in optic neuropathies