Suicidal behaviours among deaf adolescents in Ghana: a cross-sectional study.

BACKGROUND: A growing global concern is that suicide research has paid little attention to young people with disabilities, particularly, in low- and middle-income countries (LAMICs). We aimed to estimate the 12-month prevalence of suicidal ideation and attempt and describe some associations among deaf adolescents in Ghana. METHODS: This is a cross-sectional anonymous self-report survey involving a nationally representative random sample of 450 school-going deaf adolescents. Data analysis included bivariate and multivariable approaches. RESULTS: The overall 12-month prevalence of suicidal ideation was 19·3% (95% confidence interval [CI] = 15·8-23·3) and suicidal attempt was 15·6% (95% CI = 12·3-19·2). Although alcohol use and parental divorce were strongly associated with increased odds of both suicidal ideation and attempt, high subjective mental well-being was associated with reduced odds of both suicidal ideation and attempt. Living with no parents and being a final year student were associated with suicidal ideation, while male gender was associated with suicidal attempt. CONCLUSIONS: The prevalence of suicidal behaviours among school-going deaf adolescents in this study compares with estimates among in-school non-deaf adolescents in Ghana and other LAMICs in Africa, and also highlights the need for prevention efforts against the onset of suicidal ideation and possible transition to attempt and suicide among deaf adolescents.

Prevalence of Attention-Deficit/Hyperactivity Disorder Among Primary School Children in Oforikrom, Ghana Based on the Disruptive Behavior Disorders Rating Scale.

OBJECTIVE: To determine the prevalence of attention-deficit/hyperactivity disorder (ADHD) among primary school children in Oforikrom, Kumasi, Ghana. METHODS: 10 of 35 primary schools in Oforikrom were readily available. Of 2000 children aged 5 to 13 years selected, 1540 (77%) of their parents/guardians consented to participate. Their parents/guardians and six teachers from each school were asked to complete the Disruptive Behavior Disorders Rating Scale to screen children for the presence of ADHD, oppositional defiant disorder, or conduct disorder. Children who displayed symptoms (pretty much or very much) in most related items as determined by parents and/or teachers were considered positive cases. RESULTS: The mean age of 1540 pupils was 9 ± 2.16 years. Most (31%) were primary 4 pupils. 5% of pupils displayed ADHD symptoms (attention deficit disorder subtype in 36%, hyperactivity disorder subtype in 27%, and combined subtype in 37%). Of them, 51% were male. Most (19%) of those who displayed the symptoms were in primary 5. CONCLUSION: The prevalence of ADHD among primary school children in Oforikrom was 5%. 51% of those with ADHD symptoms were male. Most (19%) of those with ADHD symptoms were in primary 5.

Sucrose treatment and explant water content: critical factors to consider in development of successful cryopreservation protocols for shoot tip explants of the tropical species Dioscorea rotundata (YAM).

A study was conducted to determine the optimum methods for conditioning explants to be used in the development of a simple protocol for long-term conservation of the germplasm of Dioscorea rotundata via cryopreservation. Shoot tips from cultures maintained in vitro were exposed to high concentrations of sucrose prior to silica gel-based dehydration and vitrification solution-based cryopreservation protocols. Explant water contents were determined, and ultrastructural studies were also carried out. Initially, culturing explants on medium supplemented with 0.3 M sucrose for 3-5 d considerably reduced tissue water content from about 12.2 g/g dry mass to between 4.8 and 5.5 g/g dry mass before cryoprotection with modified PVS2 (MPVS2) or silica gel dehydration. Ultrastructural studies indicated that cells had deposits of starch in plastids following sucrose treatments. Survival for D. rotundata shoot tips treated with MPVS2 vitrification solution, unloaded with 1.0 M sucrose medium and cooled to -7 degree C, was 16 percent for 15 min treatment and 44 percent for 40 min. After the 40 min MPVS2 treatment the TTZ test indicated 88 percent viability retention of explants cooled to -70 degree C, and 44 percent at -196 degree C. Plantlet development was obtained for -70 degree C-cooled shoot tips, whereas only callus development occurred from tissues exposed to liquid nitrogen. Explant regeneration was not obtained with air-dehydration techniques. It was concluded that vitrification-solution based cryopreservation presently offers the best option for conservation of this Dioscorea species.

Inhibition of HIV-1 fusion with small interfering RNAs targeting the chemokine coreceptor CXCR4.

RNA interference (RNAi) is an evolutionarily conserved process by which plants and animals protect their genomes utilizing small, double-stranded RNAs to degrade target RNAs in a sequence-specific manner. Post-transcriptional gene silencing by these moieties can lead to degradation of both cellular and viral RNAs. It has recently been shown that double-stranded, small interfering RNAs (siRNAs) of 21-25 nucleotides can be transfected into relevant cells to target specific RNAs. This approach was utilized to inhibit human immunodeficiency virus type I (HIV-1) infection in human cells. siRNAs with homology to a motif in the mRNA that encodes for the HIV-1 chemokine coreceptor CXCR4 was utilized. Complementary studies via immunofluorescence microscopy and fluorescence-activated cell sorting demonstrated downregulation of CXCR4 from the surface of cells transfected with the specific siRNAs. As well, siRNAs without sequence homology to CXCR4 were used as controls and demonstrated no downregulation of CXCR4. siRNAs targeted to another chemokine coreceptor, APJ, showed specificity for downregulation of APJ but had no effects on CXCR4. Transfections with siRNAs targeting CXCR4 mRNA were shown to inhibit HIV-1 envelope fusion, which is relatively resistant to most viral inhibitors targeting chemokine coreceptors. The specificity of this effect was demonstrated by the inhibition of fusion by CXCR4-tropic and dual-tropic (CXCR4 and CCR5) envelope glycoproteins from HIV-1 on CXCR4+ indicator cells, but the lack of effects by siRNAs targeting CXCR4 mRNA on dual-tropic HIV-1 envelopes in CCR5+ indicator cells utilizing these fusion assays. Interestingly, siRNAs targeting CXCR4 selectively inhibited CXCR4-tropic cell-free virus infection of human cells but at only modest levels as compared to cell:cell fusion. siRNA may be a potential molecular therapeutic approach to alter a cellular cofactor critical for infection of human cells by relevant strains of HIV-1. The targeting of a cellular cofactor, rather than the HIV-1-specific mRNAs or genomic RNA, holds promise as the rapid mutational ability of the HIV-1 genome may obviate the potential clinical use of RNAi directly against this virus.

Kinetic studies on the yeast Phaffia rhodozyma.

The yeast Phaffia rhodozyma, a promising microbial producer of the carotenoid astaxanthin, was cultivated in batch and continuous processes in an agitated and aerated fermenter using an acid peat extract based culture medium. For the accelerated growth phase, the mean specific growth rate and doubling time were found to be 0.038 h-1, and 18.24 hours, respectively. The production of astaxanthin was found to be basically growth associated, the maximum concentrations of the pigment produced in batch culture and continuous cultivation being similar.