Biology subjects

Grant, I.

Publications and source records attributed to Grant, I..

4 recordsLinked to original sources

bioRxiv2020

Both HIV Infection and Conditional Tat Expression Decrease Prepulse Inhibition with Further Impairment by Methamphetamine History in Humans

HIV infection and methamphetamine (METH) use are highly comorbid and represent a significant public health problem. Both conditions are known to negatively impact a variety of brain functions. One brain function that may be affected by HIV and METH use is sensorimotor gating, an automatic, pre-conscious filtering of sensory information that is thought to contribute to higher order cognitive processes. Sensorimotor gating is often measured using prepulse inhibition (PPI), a paradigm that can be conducted in both humans and animals, thereby enabling cross-species translational studies. While previous studies suggest HIV and METH may individually impair PPI, little research has been conducted on the effects of combined HIV and METH on PPI. The goal of this cross-species study was to determine the effects of METH on PPI in the inducible Tat (iTat) mouse model of HIV and in people with HIV. PPI was measured in the iTat mouse model before, during, and after chronic METH treatment and after Tat induction. Chronic METH treatment decreased PPI in male but not female mice. PPI normalized with cessation of METH. Inducing Tat expression decreased PPI in male but not in female mice. No interactions between chronic METH treatment and Tat expression were observed in mice. In humans, HIV was associated with decreased PPI in both men and women. Furthermore, PPI was lowest in people with HIV who also had a history of METH dependence. Overall, these results suggest HIV and METH may additively impair early information processing in humans, potentially affecting downstream cognitive function. HIGHLIGHTSO_LIHIV decreased PPI in men and women C_LIO_LIPPI was most decreased in people with HIV and a history of METH dependence C_LIO_LIChronic METH treatment decreased PPI in male but not female mice C_LIO_LITat expression decreased PPI in male but not female mice C_LIO_LIChronic METH treatment and Tat expression did not interact to affect PPI in mice C_LI

neuroscience↗

bioRxiv2020

Sustained attention and vigilance deficits associated with HIV and a history of methamphetamine dependence

BackgroundHuman immunodeficiency virus (HIV)-associated neurocognitive disorders persist in the era of antiretroviral therapy (ART). One factor that is elevated among persons with HIV (PWH) and independently associated with neurocognitive impairment is methamphetamine dependence (METH+). Such dependence may further increase cognitive impairment among PWH, by delaying HIV diagnosis (and thus, ART initiation), which has been posited to account for persistent cognitive impairment among PWH, despite subsequent treatment-related viral load suppression (VLS; [≤]50 copies of the virus per milliliter in plasma or cerebrospinal fluid). This study examined the independent and combined (additive versus synergistic) effects of HIV and history of METH+ on the sustained attention and vigilance cognitive domain, while controlling for VLS. MethodsParticipants included 205 (median age=44 years; 77% males; HIV-/METH- n=67; HIV+/METH - n=49; HIV-/METH+ n=36; HIV+/METH+ n=53) individuals enrolled in the Translational Methamphetamine AIDS Research Center, who completed Conners and the 5- Choice continuous performance tests (CPTs). ResultsMETH+ participants exhibited deficits in sustained attention and vigilance; however, these effects were not significant after excluding participants who had a positive urine toxicology screen for methamphetamine. Controlling for VLS, PWH did not have worse sustained attention and vigilance, but consistently displayed slower reaction times across blocks, relative to HIV-participants. There was no HIV x METH interaction on sustained attention and vigilance. ConclusionsRecent methamphetamine use among METH+ people and detectable viral loads are detrimental to sustained attention and vigilance. These findings highlight the need for prompt diagnosis of HIV and initiation of ART, and METH use interventions.

neuroscience↗

bioRxiv2019

The impact of worldwide, national and sub-national severity distributions in Burden of Disease studies: a case study of individual cancer types in Scotland

AimThe main aim of this study was to consider the extent to which the use of worldwide severity distributions in Burden of Disease studies are influencing cross-country comparisons, by comparing Global Burden of Disease distributions with nationally derived severity distributions in Scotland for cancer types.\n\nMethodsWe obtained individual records from the Scottish Cancer Registry for 21 cancer types and linked these to registered deaths. We estimated prevalent cancer cases for 2016 and assigned each case to sequelae using Global Burden of Disease (GBD) 2016 study definitions. We compared the impact of using severity distributions based on GBD 2016, a Scotland-wide distribution, and a distribution specific to deprivation strata in Scotland, on the weighted-average disability weights for each cancer type in Scotland.\n\nResultsThe relative difference in point estimates of weighted-average disability weights based on GBD 2016 worldwide severity distributions compared with Scottish national severity distributions resulted in overestimates in the majority of cancers (17 out of 21 cancer types). The largest overestimates were for gallbladder and biliary tract cancer (70.8%), oesophageal cancer (31.6%) and pancreatic cancer (31.2%). Furthermore, the use of weighted-average disability weights based on Scottish national severity distributions rather than sub-national Scottish severity distributions stratified by deprivation quintile overestimated weighted-average disability weights in the least deprived areas (16 out of 18 cancer types), and underestimated in the most deprived areas (16 out of 18 cancer types).\n\nConclusionOur findings illustrate a bias in point estimates of weighted-average disability weights created using worldwide severity distributions. This bias would have led to the misrepresentation of non-fatal estimates of the burden of individual cancers, and underestimated the scale of socioeconomic inequality in this non-fatal burden. This highlights the importance of not interpreting non-fatal estimates of burden of disease too precisely, especially for sub-national estimates and those comparing populations when relying on data inputs from other countries. It is essential to ensure that any estimates are based upon the best available country-specific data at the lowest granularity.

epidemiology↗

bioRxiv2018

Fetal and trophoblast PI3Kp110α have distinct roles in regulating resource supply to the growing fetus

Previous studies suggest that the placental supply of nutrients to the fetus adapts according to fetal demand. However, the signaling events underlying placental adaptations remain largely unknown. Earlier work in mice has revealed that loss of the phosphoinositide 3-kinase p110 impairs feto-placental growth but placental nutrient supply is adaptively increased. Here we explore the role of p110 in the epiblast-derived (fetal) and trophoblast lineages of the conceptus in relation to feto-placental growth and placental development and transfer function. Using conditional gene manipulations to knock-down p110 either by [~]50% or [~]100% in the fetal lineages and/or trophoblast, this study shows that p110 in the fetus is essential for prenatal development and a major regulator of placental phenotype in mice. Complete loss of fetal p110 caused embryonic death, whilst heterozygous loss resulted in fetal growth restriction and impaired placental formation and nutrient transport. Loss of trophoblast p110 also resulted in abnormal placental development, although fetuses were viable. However, in response to complete loss of trophoblast p110, the placenta failed to transport sufficient amino acid to match fetal demands for growth. Using RNA-seq, we identified several genes downstream of p110 in the trophoblast that are important in adapting placental phenotype to support fetal growth. Further work using CRISPR/Cas9 genome targeting showed that loss of p110 differentially affects the expression of genes in trophoblast and embryonic stem cells. Our findings thus reveal important, but distinct roles for p110 signaling in the different compartments of the conceptus, which control fetal resource acquisition and ultimately affect healthy growth.\n\nOne Sentence SummaryFetal and trophoblast p110 modify resource allocation

developmental biology↗