3,372 research outputs found
Inactivation of Eα and EÎČ expression in inbred and wild mice by multiple distinct mutations, some of which predate speciation within Mus species
The H-2 MHC of mice encodes two functional class II heterodimeric proteins: AαAÎČ (A) and EαEÎČ (E). While failure to express the A protein has not been reported, a significant proportion of of H-2 haplotypes In both Inbred and wild mice do not express E proteins. We and others have previously characterized the molecular basis for defective E expression in haplotypes from Mus domestlcus (b, f, q, s, from inbred strains) and Af. castaneus (w17, wild-derived) species, identifying six distinct defects in the genes for Eα or EÎČ. In this report we have extended these studies to other E- haplotypes, Including several from f-haplotype-bearlng M. domesticus mice (w29, w57, w302) and one derived from the Asian species M. bactrianus (w301). Analyses at the protein, RNA and DNA levels were employed to Identify the defects in the genes for Ea and Eb. At least one new defect was identified that prevents EÎČ expression in a t-associated H-2 haplotypes (w57), bringing the number of distinct mutations causing the EÎČ phenotype to seven. Another t-associated haplotype, w302, was found to share the same EÎČ defect with mice of the inbred q haplotype and of the w17 haplotype from Af. castaneus, while its Ea gene contains the deletion carried also by the Inbred b and s haplotypes and by a number of wild haplotypes. The mutations in the Ea and Eb genes of the w301 haplotype from M. bactrianus were found to be Identical to those of the Inbred f haplotype. This indicates that the origin of the mutations in the Eb genes of the q, w17 and w302 haplotypes and in the Ea and Eb genes of the f and w301 haplotypes, predated speciation within Mus, thought to have occurred âŒ0.35-1 million years ago. Their maintenance in mouse populations suggests that in certain conditions the failure to express EαEÎČ proteins may be advantageous and selected fo
Factors Related to Youth Living with HIV Delaying Access to Care: The Role of Positive and Negative Social Network Influences on Health Seeking Behaviors
To explore factors related to youthsâ delay in seeking care after an HIV diagnosis. Multivariate analyses were performed on 347 participants who were selected from a sample of 351 adolescents participating in a 1994-1996 survey among youth in four U.S. metropolitan cities. Key findings were that participants with prosocial peer behaviors took longer (34 days) to seek care than youth with poorer social engagement and excessive fibbing delayed seeking care (23 days). Potentially important findings suggest being female, older, having close peer networks, conduct problems, and certain housing settings may delay seeking care. Multivariate regression analyses indicate that later entry into medical care was observed among those with close social networks and behavioral characteristics related to delinquency
Recommended from our members
18 F-AV1451 PET imaging and multimodal MRI changes in progressive supranuclear palsy
Funder: PSP Association; doi: http://dx.doi.org/10.13039/100011707Abstract: Objectives: Progressive supranuclear palsy (PSP) is characterized by deposition of straight filament tau aggregates in the grey matter (GM) of deep nuclei and cerebellum. We examined the relationship between tau pathology (assessed via 18F-AV1451 PET) and multimodal MRI imaging using GM volume, cortical thickness (CTh), and diffusion tensor imaging (DTI). Methods: Twenty-three people with clinically probable PSP-Richardsonâs syndrome (age 68.8 ± 5.8 years, 39% female) and 23 controls underwent structural 3 T brain MRI including DTI. Twenty-one patients also had 18F-AV1451 PET imaging. Voxelwise volume-based morphometry, surface-based morphometry, and DTI correlations were performed with 18F-AV1451 binding in typical PSP regions of interest (putamen, thalamus and dentate cerebellum). Clinical impairment was also assessed in relation to the different imaging modalities. Results: PSP subjects showed GM volume loss in frontotemporal regions, basal ganglia, midbrain, and cerebellum (FDR-corrected p < 0.05), reduced CTh in the left entorhinal and fusiform gyrus (p < 0.001) as well as DTI changes in the corpus callosum, internal capsule, and superior longitudinal fasciculus (FWE-corrected p < 0.05). In PSP, higher 18F-AV1451 binding correlated with GM volume loss in frontal regions, DTI changes in motor tracts, and cortical thinning in parietooccipital areas. Cognitive impairment was related to decreased GM volume in frontotemporal regions, thalamus and pallidum, as well as DTI alteration in corpus callosum and cingulum. Conclusion: This cross-sectional study demonstrates an association between in vivo proxy measures of tau pathology and grey and white matter degeneration in PSP. This adds to the present literature about the complex interplay between structural changes and protein deposition
Premature atrial and ventricular contractions detected on wearable-format electrocardiograms and prediction of cardiovascular events
AIMS: Wearable devices are transforming the electrocardiogram (ECG) into a ubiquitous medical test. This study assesses the association between premature ventricular and atrial contractions (PVCs and PACs) detected on wearable-format ECGs (15 s single lead) and cardiovascular outcomes in individuals without cardiovascular disease (CVD). METHODS AND RESULTS: Premature atrial contractions and PVCs were identified in 15 s single-lead ECGs from N = 54 016 UK Biobank participants (median age, interquartile range, age 58, 50-63 years, 54% female). Cox regression models adjusted for traditional risk factors were used to determine associations with atrial fibrillation (AF), heart failure (HF), myocardial infarction (MI), stroke, life-threatening ventricular arrhythmias (LTVAs), and mortality over a period of 11.5 (11.4-11.7) years. The strongest associations were found between PVCs (prevalence 2.2%) and HF (hazard ratio, HR, 95% confidence interval = 2.09, 1.58-2.78) and between PACs (prevalence 1.9%) and AF (HR = 2.52, 2.11-3.01), with shorter prematurity further increasing risk. Premature ventricular contractions and PACs were also associated with LTVA (P < 0.05). Associations with MI, stroke, and mortality were significant only in unadjusted models. In a separate UK Biobank sub-study sample [UKB-2, N = 29,324, age 64, 58-60 years, 54% female, follow-up 3.5 (2.6-4.8) years] used for independent validation, after adjusting for risk factors, PACs were associated with AF (HR = 1.80, 1.12-2.89) and PVCs with HF (HR = 2.32, 1.28-4.22). CONCLUSION: In middle-aged individuals without CVD, premature contractions identified in 15 s single-lead ECGs are strongly associated with an increased risk of AF and HF. These data warrant further investigation to assess the role of wearable ECGs for early cardiovascular risk stratification
Premature atrial and ventricular contractions detected on wearable-format electrocardiograms and prediction of cardiovascular events
Aims: Wearable devices are transforming the electrocardiogram (ECG) into a ubiquitous medical test. This study assesses the association between premature ventricular and atrial contractions (PVCs and PACs) detected on wearable-format ECGs (15 s single lead) and cardiovascular outcomes in individuals without cardiovascular disease (CVD). Methods and results: Premature atrial contractions and PVCs were identified in 15 s single-lead ECGs from N = 54 016 UK Biobank participants (median age, interquartile range, age 58, 50â63 years, 54% female). Cox regression models adjusted for traditional risk factors were used to determine associations with atrial fibrillation (AF), heart failure (HF), myocardial infarction (MI), stroke, life-threatening ventricular arrhythmias (LTVAs), and mortality over a period of 11.5 (11.4â11.7) years. The strongest associations were found between PVCs (prevalence 2.2%) and HF (hazard ratio, HR, 95% confidence interval = 2.09, 1.58â2.78) and between PACs (prevalence 1.9%) and AF (HR = 2.52, 2.11â3.01), with shorter prematurity further increasing risk. Premature ventricular contractions and PACs were also associated with LTVA (P < 0.05). Associations with MI, stroke, and mortality were significant only in unadjusted models. In a separate UK Biobank sub-study sample [UKB-2, N = 29,324, age 64, 58â60 years, 54% female, follow-up 3.5 (2.6â4.8) years] used for independent validation, after adjusting for risk factors, PACs were associated with AF (HR = 1.80, 1.12â2.89) and PVCs with HF (HR = 2.32, 1.28â4.22). Conclusion: In middle-aged individuals without CVD, premature contractions identified in 15 s single-lead ECGs are strongly associated with an increased risk of AF and HF. These data warrant further investigation to assess the role of wearable ECGs for early cardiovascular risk stratification
Long-term association of ultra-short heart rate variability with cardiovascular events
Heart rate variability (HRV) is a cardiac autonomic marker with predictive value in cardiac patients. Ultra-short HRV (usHRV) can be measured at scale using standard and wearable ECGs, but its association with cardiovascular events in the general population is undetermined. We aimed to validate usHRV measured usingââ€â15-s ECGs (using RMSSD, SDSD and PHF indices) and investigate its association with atrial fibrillation, major adverse cardiac events, stroke and mortality in individuals without cardiovascular disease. In the National Survey for Health and Development (nâ=â1337 participants), agreement between 15-s and 6-min HRV, assessed with correlation analysis and Bland-Altman plots, was very good for RMSSD and SDSD and good for PHF. In the UK Biobank (nâ=â51,628 participants, 64% male, median age 58), after a median follow-up of 11.5 (11.4-11.7) years, incidence of outcomes ranged between 1.7% and 4.3%. Non-linear Cox regression analysis showed that reduced usHRV from 15-, 10- and 5-s ECGs was associated with all outcomes. Individuals with low usHRV (<â20th percentile) had hazard ratios for outcomes between 1.16 and 1.29, pâ<â0.05, with respect to the reference group. In conclusion, usHRV fromââ€â15-s ECGs correlates with standard short-term HRV and predicts increased risk of cardiovascular events in a large population-representative cohort
Child and parental sleep in young children with epilepsy: A population-based case-control study
Objective:
To determine the prevalence of parentâreported sleep problems in young children with epilepsy and their parents, and to compare findings with those in a nonâepilepsyârelated neurodisability (neurodevelopmental/neurological difficulties) group.
Method:
Parents of young children (1â7 years) with epilepsy (n = 48 [91% ascertainment]) completed the Child Sleep Habits Questionnaire (CSHQ). Parents (mothers and fathers) also completed the Pittsburgh Sleep Quality Index (PSQI) and the Iowa Fatigue Scale (IFS) in relation to their own functioning. The responses of parents of children with epilepsy were compared with parents of developmentalâ, ageâ, and genderâmatched children with nonepilepsyârelated neurodisability (n = 48).
Results:
There was not a significant difference in the proportion of children with epilepsy and the children with neurodisability scoring in the atârisk range on the CSHQ (81% vs. 71% respectively) (p = 0.232). 62% of mothers and 44% of fathers of children with epilepsy had âpoor quality sleepâ on the PSQI; there was not a significant difference between mothers of children with epilepsy and those of children with neurodisability (p = 0.526) or IFS (p = 0.245) total scores. However, mothers of children with epilepsy had significantly more difficulties on the productivity subscale of the IFS (p = 0.004). There were no significant differences between fathersâ scores on either measure. In the epilepsy group, child behavioral problems (p = 0.001) were independently associated with child sleep difficulties and maternal mental health problems were associated with parental sleep difficulties (p = 0.04) and fatigue (p = 0.018).
Significance:
Young children with epilepsy and their parents have a high rate of sleep difficulties. There is a need to develop effective interventions for this population, taking into consideration of the role of child behavioral problems and parental mental health difficulties
Parameterizing the impact of seawater temperature and irradiance on dimethylsulfide (DMS) in the Great Barrier Reef and the contribution of coral reefs to the global sulfur cycle
© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Jackson, R. L., Gabric, A. J., Matrai, P. A., Woodhouse, M. T., Cropp, R., Jones, G. B., Deschaseaux, E. S. M., Omori, Y., McParland, E. L., Swan, H. B., & Tanimoto, H. Parameterizing the impact of seawater temperature and irradiance on dimethylsulfide (DMS) in the Great Barrier Reef and the contribution of coral reefs to the global sulfur cycle. Journal of Geophysical Research:Oceans, 126(3), (2021): e2020JC016783, https://doi.org/10.1029/2020JC016783.Biogenic emissions of dimethylsulfide (DMS) are an important source of sulfur to the atmosphere, with implications for aerosol formation and cloud albedo over the ocean. Natural aerosol sources constitute the largest uncertainty in estimates of aerosol radiative forcing and climate and thus, an improved understanding of DMS sources is needed. Coral reefs are strong point sources of DMS; however, this coral source of biogenic sulfur is not explicitly included in climatologies or in model simulations. Consequently, the role of coral reefs in local and regional climate remains uncertain. We aim to improve the representation of tropical coral reefs in DMS databases by calculating a climatology of seawater DMS concentration (DMSw) and sea-air flux in the Great Barrier Reef (GBR), Australia. DMSw is calculated from remotely sensed observations of sea surface temperature and photosynthetically active radiation using a multiple linear regression model derived from field observations of DMSw in the GBR. We estimate that coral reefs and lagoon waters in the GBR (âŒ347,000 km2) release 0.03â0.05 Tg yrâ1 of DMS (0.02 Tg yrâ1 of sulfur). Based on this estimate, global tropical coral reefs (âŒ600,000 km2) could emit 0.08 Tg yrâ1 of DMS (0.04 Tg yrâ1 of sulfur), with the potential to influence the local radiative balance.Australian Research Council. Grant Number: DP150101649
National Science Foundation (NSF). Grant Number: 1543450
Ministry of Education, Culture, Sports, Science and Technology Grants-in-Aid for Scientific Research. Grant Number: 23310016,16H02967,24241010,15H01732
Ministry of Education, Culture, Sports, Science and Technology Grant-in-Aid for Young Scientists. Grant Number: 17K1281
Circadian rhythm of hepatic cytosolic and nuclear estrogen receptors
The distribution of estrogen receptor between the cytosolic and nuclear compartments were evaluated in liver of male rats to determine whether a circadian rhythm exists. Cytosolic receptor reached a maximum level at 400 hours and a minimum at 2000 and 2400 hr. Nuclear receptor reached a maximum level at 800 hr and was lowest at 1600 and 2000 hr. Serum estradiol levels were also highest at 800 hr and lowest at 1600 hr. The variations in cytosolic and nuclear receptors are not reciprocal; in fact, the overall content of receptor in the liver is not constant and also displays a circadian rhythm. © 1986 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted
- âŠ