Studies of Tiros and Nimbus radiometric observations Final report

Data analyses of Tiros and Nimbus radiometric observation

Uptake of HIV testing among 15–19-year-old adolescents in Zambia

Adolescent HIV testing rates remain low with many unaware of their status. We explored factors associated with HIV testing uptake among adolescents aged 15–19 years using data from the Zambian Demographic Health Survey 2013–2014. The sample consisted of 7030 adolescents of which 42% reported ever testing for HIV. We found that as the age of a respondent increased so did their odds of testing (aOR = 1.26; 1.21–1.32); females had higher odds of testing than males (aOR = 1.719; 1.53–1.92); those with secondary or higher education (aOR = 3.64; 2.23–5.96) and those with primary education (aOR=1.97; 1.21–3.19) had higher odds of testing than those with no education; those who were formerly married or living with a partner (aOR =  4.99; 2.32–10.75) and those who were currently married or living with a partner (aOR = 4.76; 3.65–6.21) had higher odds of testing than those who were never married or lived with a partner; as the age at first sexual intercourse increased so did the odds of testing (aOR = 1.07; 1.06–1.08); and as HIV knowledge increased so did the odds of testing (aOR = 1.13; 1.06–1.19). The data points to population level social determinants that may be targeted to increase testing among adolescents

The Importance of DNA Repair in Tumor Suppression

The transition from a normal to cancerous cell requires a number of highly specific mutations that affect cell cycle regulation, apoptosis, differentiation, and many other cell functions. One hallmark of cancerous genomes is genomic instability, with mutation rates far greater than those of normal cells. In microsatellite instability (MIN tumors), these are often caused by damage to mismatch repair genes, allowing further mutation of the genome and tumor progression. These mutation rates may lie near the error catastrophe found in the quasispecies model of adaptive RNA genomes, suggesting that further increasing mutation rates will destroy cancerous genomes. However, recent results have demonstrated that DNA genomes exhibit an error threshold at mutation rates far lower than their conservative counterparts. Furthermore, while the maximum viable mutation rate in conservative systems increases indefinitely with increasing master sequence fitness, the semiconservative threshold plateaus at a relatively low value. This implies a paradox, wherein inaccessible mutation rates are found in viable tumor cells. In this paper, we address this paradox, demonstrating an isomorphism between the conservatively replicating (RNA) quasispecies model and the semiconservative (DNA) model with post-methylation DNA repair mechanisms impaired. Thus, as DNA repair becomes inactivated, the maximum viable mutation rate increases smoothly to that of a conservatively replicating system on a transformed landscape, with an upper bound that is dependent on replication rates. We postulate that inactivation of post-methylation repair mechanisms are fundamental to the progression of a tumor cell and hence these mechanisms act as a method for prevention and destruction of cancerous genomes.Comment: 7 pages, 5 figures; Approximation replaced with exact calculation; Minor error corrected; Minor changes to model syste

Activity and phylogenetic diversity of bacterial cells with high and low nucleic acid content and electron transport system activity in an upwelling ecosystem

We evaluated whether bacteria with higher cell-specific nucleic acid content (HNA) or an active electron transport system, i.e., positive for reduction of 5-cyano-2,3-ditolyl tetrazolium chloride (CTC), were responsible for the bulk of bacterioplankton metabolic activity. We also examined whether the phylogenetic diversity of HNA and CTC-positive cells differed from the diversity of Bacteria with low nucleic acid content (LNA). Bacterial assemblages were sampled both in eutrophic shelf waters and in mesotrophic offshore waters in the Oregon coastal upwelling region. Cytometrically sorted HNA, LNA, and CTC-positive cells were assayed for their cell-specific [³H]leucine incorporation rates. Phylogenetic diversity in sorted non-radioactively labeled samples was assayed using denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA genes. Cell-specific rates of leucine incorporation of HNA and CTC-positive cells were on average only slightly greater than the cell-specific rates of LNA cells. HNA cells accounted for most bacterioplankton substrate incorporation due to high abundances, while the low abundances of CTC-positive cells resulted in only a small contribution by these cells to total bacterial activity. The proportion of the total bacterial leucine incorporation attributable to LNA cells was higher in offshore regions than in shelf waters. Sequence data obtained from DGGE bands showed broadly similar phylogenetic diversity across HNA, LNA, and CTC-positive cells, with between-sample and between-region variability in the distribution of phylotypes. Our results suggest that LNA bacteria are not substantially different from HNA bacteria in either cell-specific rates of substrate incorporation or phylogenetic composition and that they can be significant contributors to bacterial metabolism in the sea

Prevalence of pain in women living with HIV aged 45-60: associated factors and impact on patient-reported outcomes

As the population of women with HIV ages, an increasing proportion are experiencing the menopause, with potential associated pain. Among 844 participants in the Positive Transitions Through the Menopause (PRIME) study (72.3% black African; median age 49 (interquartile-range 47-53) years; 20.9%, 44.0% and 35.1% pre-, peri- and post-menopausal), 376 (44.6%) and 73 (8.7%) reported moderate or extreme pain. Women had been diagnosed with HIV for 14 (9-18) years, 97.7% were receiving antiretroviral therapy and 88.4% had a suppressed viral load. In adjusted ordinal logistic regression, peri-menopausal status (adjusted odds ratio (1.80) [95% confidence interval 1.22-2.67]), current smoking (1.85 [1.11-3.09]), number of comorbid conditions (1.95 [1.64-2.33] /condition) and longer duration of HIV (1.12 [1.00-1.24]/5 years) were independently associated with increased reported pain, whereas being in full-time work (0.61 [0.45-0.83]) and having enough money for basic needs (0.47 [0.34-0.64]) were associated with decreased pain reporting. Increasing pain was independently related to insomnia symptoms (moderate: 2.76 [1.96-3.90]; extreme: 8.09 [4.03-16.24]) and severe depressive symptoms (PHQ4 ≥ 6; moderate: 3.96 [2.50-6.28]; extreme: 9.13 [4.45-18.72]). Whilst our analyses cannot determine the direction of any associations, our findings point to the importance of eliciting a history of pain and addressing symptoms in order to improve wellbeing

The Role of Corpus Callosum Development in Functional Connectivity and Cognitive Processing

The corpus callosum is hypothesized to play a fundamental role in integrating information and mediating complex behaviors. Here, we demonstrate that lack of normal callosal development can lead to deficits in functional connectivity that are related to impairments in specific cognitive domains. We examined resting-state functional connectivity in individuals with agenesis of the corpus callosum (AgCC) and matched controls using magnetoencephalographic imaging (MEG-I) of coherence in the alpha (8–12 Hz), beta (12–30 Hz) and gamma (30–55 Hz) bands. Global connectivity (GC) was defined as synchronization between a region and the rest of the brain. In AgCC individuals, alpha band GC was significantly reduced in the dorsolateral pre-frontal (DLPFC), posterior parietal (PPC) and parieto-occipital cortices (PO). No significant differences in GC were seen in either the beta or gamma bands. We also explored the hypothesis that, in AgCC, this regional reduction in functional connectivity is explained primarily by a specific reduction in interhemispheric connectivity. However, our data suggest that reduced connectivity in these regions is driven by faulty coupling in both inter- and intrahemispheric connectivity. We also assessed whether the degree of connectivity correlated with behavioral performance, focusing on cognitive measures known to be impaired in AgCC individuals. Neuropsychological measures of verbal processing speed were significantly correlated with resting-state functional connectivity of the left medial and superior temporal lobe in AgCC participants. Connectivity of DLPFC correlated strongly with performance on the Tower of London in the AgCC cohort. These findings indicate that the abnormal callosal development produces salient but selective (alpha band only) resting-state functional connectivity disruptions that correlate with cognitive impairment. Understanding the relationship between impoverished functional connectivity and cognition is a key step in identifying the neural mechanisms of language and executive dysfunction in common neurodevelopmental and psychiatric disorders where disruptions of callosal development are consistently identified

Hematoma Enlargement Among Patients with Traumatic Brain Injury: Analysis of a Prospective Multicenter Clinical Trial

Observational studies suggest that hematomas continue to enlarge during hospitalization in patients with traumatic brain injury (TBI). There is limited data regarding factors associated with hematoma enlargement and on whether hematoma enlargement contributes directly to death and disability in patients with TBI. We analyzed data collected as part of the Resuscitation Outcomes Consortium Hypertonic Saline and TBI Study. Hematoma enlargement was ascertained and collected as a predefined safety endpoint. We evaluated the effect of hematoma enlargement on the risk of death and disability at 6 months based on the Extended Glasgow Outcome Scale (GOSE) (dichotomized as \u3e4 or ≤4) using stepwise logistic regression analysis. We adjusted for age (continuous variable), admission GCS score (dichotomized at \u3e5 and ≤5), and computed tomography (CT) scan classification (Marshall grades entered as a categorical variable). Of the 1200 patients with severe TBI analyzed, 238 (19.8%) patients were reported to have hematoma enlargement as an adverse event. The proportion of patients who reached favorable outcome at 6 months was significantly lower (defined by GOSE of \u3e4) among patients with hematoma enlargement (29.0% vs. 40.1%, p\u3c.0001). The proportion of patients who died within 6 months was significantly higher among patients with hematoma enlargement (31.9% vs. 20.7%, p\u3c.0001). After adjusting for age, admission GCS score, and initial injury score, the odds of favorable outcome was lower in patients with hematoma enlargement (odds ratio 0.7, 95% confidence interval [CI]; 0.5–0.97). Our results suggest that hematoma enlargement may be a direct contributor to death and disability in patients with TBI at 6 months. Future clinical trials must continue to evaluate new therapeutic interventions aimed at reducing hematoma enlargement with a favorable risk benefit ratio in patients with TBI

Food Should not be Forgotten: Impacts of Combined Cash Transfer Receipt and Food Security on Child Education and Cognition in South Africa and Malawi.

Social protection can take many forms. Both cash transfers and food security may have important contributions to child cognitive development. This study examines the potential impact of combinations of cash transfers and food security status on child cognitive development and educational outcomes. Cross-sectional data for 796 HIV-affected children in the Child Community Care study were utilised for this analysis. Children and caregivers completed interview schedules comprised of standardised items on socio-demographics, household data, cash grant receipt and food security status, school achievement, and cognition. A series of logistic and linear regression models and marginal effects analyses were undertaken to explore the impacts of differing levels of social protection (none; either cash grant receipt or food secure status or, both in combination) on child educational and cognitive outcomes. Although all children lived in poverty-stricken households, 20% (157/796) of children did not live in a household in receipt of a cash grant and did not report food security; 32.4% (258/796) reported either component of social protection and, 47.9% (381/796) received both measures of social protection in combination. Compared to no social protection, being in receipt of either component of social protection was found to be significantly associated with being in the correct class for age, higher scores of non-verbal cognition, and higher working memory scores. Receiving both social protection measures in combination was found to be significantly associated with reduced educational risk scores, improved odds of being in the correct class for age, regular school attendance, missing less than a week of school in the previous two weeks, higher scores on measures of nonverbal cognition, higher working memory scores, and learning new things more easily. Educational and cognitive outcomes for children can be bolstered by social protection measures (cash grant receipt or food security). Benefits are enhanced when social protection is received in combination. Such findings support the notion of synergistic social protection responses for children living in environments impacted by high levels of HIV burden and deprivation

Does pre-COVID impulsive behaviour predict adherence to hygiene and social distancing measures in youths following the COVID-19 pandemic onset? Evidence from a South African longitudinal study

BACKGROUND: Engagement in protective behaviours relating to the COVID-19 pandemic has been proposed to be key to infection control. This is particularly the case for youths as key drivers of infections. A range of factors influencing adherence have been identified, including impulsivity and risk taking. We assessed the association between pre-COVID impulsivity levels and engagement in preventative measures during the COVID-19 pandemic in a longitudinal South African sample, in order to inform future pandemic planning. METHODS: Data were collected from N = 214 youths (mean age at baseline: M = 17.81 (SD = .71), 55.6% female) living in a South African peri-urban settlement characterised by high poverty and deprivation. Baseline assessments were taken in 2018/19 and the COVID follow-up was conducted in June–October 2020 via remote data collection. Impulsivity was assessed using the Balloon Analogue Task (BART), while hygiene and social distancing behaviours were captured through self-report. Stepwise hierarchical regression analyses were performed to estimate effects of impulsivity on measure adherence. RESULTS: Self-rated engagement in hygiene behaviours was high (67.1–86.1% “most of the time”, except for “coughing/sneezing into one’s elbow” at 33.3%), while engagement in social distancing behaviours varied (22.4–57.8% “most of the time”). Higher impulsivity predicted lower levels of hygiene (β = .14, p = .041) but not social distancing behaviours (β = −.02, p = .82). This association was retained when controlling for a range of demographic and COVID-related factors (β = .14, p = .047) and was slightly reduced when including the effects of a life-skills interventions on hygiene behaviour (β = −.13, p = .073). CONCLUSIONS: Our data indicate that impulsivity may predict adolescent engagement in hygiene behaviours post COVID-19 pandemic onset in a high risk, sub-Saharan African setting, albeit with a small effect size. For future pandemics, it is important to understand predictors of engagement, particularly in the context of adversity, where adherence may be challenging. Limitations include a small sample size and potential measure shortcomings