Investigating the effects of dopamine on short- and long-latency afferent inhibition.

Short- and long-latency afferent inhibition (SAI and LAI respectively) are phenomenon whereby the motor evoked potential induced by transcranial magnetic stimulation (TMS) is inhibited by a sensory afferent volley consequent to nerve stimulation. It remains unclear whether dopamine participates in the genesis or modulation of SAI and LAI. The present study aimed to determine if SAI and LAI are modulated by levodopa (l-DOPA). In this placebo-controlled, double-anonymized study Apo-Levocarb (100 mg l-DOPA in combination with 25 mg carbidopa) and a placebo were administered to 32 adult males (mean age 24 ± 3 years) in two separate sessions. SAI and LAI were evoked by stimulating the median nerve and delivering single-pulse TMS over the motor hotspot corresponding to the first dorsal interosseous muscle of the right hand. SAI and LAI were quantified before and 1 h following ingestion of drug or placebo corresponding to the peak plasma concentration of Apo-Levocarb. The results indicate that Apo-Levocarb increases SAI and does not significantly alter LAI. These findings support literature demonstrating increased SAI following exogenous dopamine administration in neurodegenerative disorders. KEY POINTS: Short- and long-latency afferent inhibition (SAI and LAI respectively) are measures of corticospinal excitability evoked using transcranial magnetic stimulation. SAI and LAI are reduced in conditions such as Parkinson's disease which suggests dopamine may be involved in the mechanism of afferent inhibition. 125 mg of Apo-Levocarb (100 mg dopamine) increases SAI but not LAI. This study increases our understanding of the pharmacological mechanism of SAI and LAI.

Age- and sex-specific associations of frailty with mortality and healthcare utilization in community-dwelling adults from ontario, Canada.

BACKGROUND: Understanding how health trajectories are related to the likelihood of adverse outcomes and healthcare utilization is key to planning effective strategies for improving health span and the delivery of care to older adults. Frailty measures are useful tools for risk stratification in community-based and primary care settings, although their effectiveness in adults younger than 60 is not well described. METHODS: We performed a 10-year retrospective analysis of secondary data from the Ontario Health Study, which included 161,149 adults aged ≥ 18. Outcomes including all-cause mortality and hospital admissions were obtained through linkage to ICES administrative databases with a median follow-up of 7.1-years. Frailty was characterized using a 30-item frailty index. RESULTS: Frailty increased linearly with age and was higher for women at all ages. A 0.1-increase in frailty was significantly associated with mortality (HR = 1.47), the total number of outpatient (IRR = 1.35) and inpatient (IRR = 1.60) admissions over time, and length of stay (IRR = 1.12). However, with exception to length of stay, these estimates differed depending on age and sex. The hazard of death associated with frailty was greater at younger ages, particularly in women. Associations with admissions also decreased with age, similarly between sexes for outpatient visits and more so in men for inpatient. CONCLUSIONS: These findings suggest that frailty is an important health construct for both younger and older adults. Hence targeted interventions to reduce the impact of frailty before the age of 60 would likely have important economic and social implications in both the short- and long-term.

Risk Factors and Clinical Outcomes Associated With Sarcopenia in Rheumatoid Arthritis: A Systematic Review and Meta-analysis.

ABSTRACT: Sarcopenia is underrecognized in patients with rheumatoid arthritis (RA). Risk factors of sarcopenia and its impact on outcomes in RA patients are relatively unknown. We conducted a systematic review to identify factors and outcomes associated with sarcopenia in RA. We conducted this review according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) 2020 guidelines. We searched PubMed, Embase, CINAHL, and Web of Science databases by combining the following search concepts: (1) RA and (2) sarcopenia. Articles were included if they included RA patients, assessed for sarcopenia using a consensus working group definition, and assessed for clinical outcomes. Meta-analysis was performed using studies that shared the same sarcopenia definition and consistency in reporting patient or disease variables. Our search identified 3602 articles. After removal of duplicates, title and abstract screen, and full-text review, 16 articles were included for final analysis. All studies had observational study designs. The pooled prevalence of sarcopenia ranged from 24% to 30%, depending on the criteria for sarcopenia used. Factors associated with sarcopenia included higher 28-joint Disease Activity Scale scores (+0.39; 95% confidence interval, +0.02 to +0.77) and baseline methotrexate use (odds ratio, 0.70; 95% confidence interval, 0.51-0.97). Baseline glucocorticoid use had a positive correlation with sarcopenia in multiple studies. Several studies found lower bone mineral density and higher incidence of falls and fractures in patients with sarcopenia. Sarcopenia is prevalent in RA, and it may be associated with higher RA disease activity, lower bone mineral density, and increased falls and fractures. Therefore, early screening of sarcopenia in RA patients is important to incorporate into clinical rheumatology practice.

Risk factors associated with prevalent vertebral fractures in Duchenne muscular dystrophy.

Patients with Duchenne muscular dystrophy (DMD) have a high fracture burden due to progressive myopathy and steroid-induced osteoporosis. This study in males with DMD showed that markers of systemic glucocorticoid exposure including shorter stature, greater bone age delay, and lower lumbar spine bone mineral density were associated with spine fragility. INTRODUCTION: Fragility  fractures are frequent in DMD. The purpose of this study was to identify clinical factors associated with prevalent vertebral fractures (VF) in boys, teens/young adults with Duchenne muscular dystrophy (DMD). METHODS: This was a cross-sectional study of males aged 4-25 years with DMD. VF were evaluated using the modified Genant semi-quantitative method on T4-L4 lateral spine radiographs. Areal bone mineral density (aBMD) was measured at the lumbar spine (LS) and used to estimate volumetric BMD (vBMD). Clinical factors were analyzed for their association with the Spinal Deformity Index (SDI, the sum of the Genant grades). RESULTS: Sixty participants were enrolled (mean age 11.5 years, range 5.4-19.5). Nineteen participants (32%) had a total of 67 VF; 23/67 VF (34%) were moderate or severe. Participants with VF were shorter (mean height Z-score ± standard deviation: - 3.1 ± 1.4 vs. - 1.8 ± 1.4, p = 0.001), had longer glucocorticoid exposure (mean duration 6.0 ± 3.3 vs. 3.9 ± 3.3 years, p = 0.027), greater bone age (BA) delay (mean BA to chronological age difference - 3.2 ± 3.4 vs. - 1.3 ± 1.2 years, p = 0.035), and lower LSaBMD Z-scores (mean - 3.0 ± 1.0 vs. - 2.2 ± 1.2, p = 0.023). There was no difference in LSvBMD Z-scores. Multivariable Poisson regression showed that every 0.1 mg/kg/day increment in average glucocorticoid daily dose was associated with a 1.4-fold SDI increase (95% confidence interval: 1.1-1.7, p = 0.013). Greater BA delay (p < 0.001), higher weight Z-score (p = 0.004), decreased height Z-score (p = 0.025), and lower LSvBMD Z-score (p = 0.025) were also associated with SDI increase. CONCLUSION: Readily measurable clinical variables were associated with prevalent VF in males with glucocorticoid-treated DMD. These variables may be useful to identify candidates for primary osteoporosis prevention after glucocorticoid initiation.

Using logistic regression models to investigate the effects of high-sensitivity cardiac troponin T confounders on ruling in acute myocardial infarction.

OBJECTIVES: Confounding factors, including sex, age, and renal dysfunction, affect high-sensitivity cardiac troponin T (hs-cTnT) concentrations and the acute myocardial infarction (AMI) diagnosis. This study assessed the effects of these confounders through logistic regression models and evaluated the diagnostic performance of an optimized, integrated prediction model. METHODS: This retrospective study included a primary derivation cohort of 18,022 emergency department (ED) patients at a US medical center and a validation cohort of 890 ED patients at a Canadian medical center. Hs-cTnT was measured with 0/3 h sampling. The primary outcome was index AMI diagnosis. Logistic regression models were optimized to predict AMI using delta hs-cTnT and its confounders as covariates. The diagnostic performance of model cutoffs was compared to that of the hs-cTnT delta thresholds. Serial logistic regressions were carried out to evaluate the relationship between covariates. RESULTS: The area under the curve of the best-fitted model was 0.95. The model achieved a 90.0% diagnostic accuracy in the validation cohort. The optimal model cutoff yielded comparable performance (90.5% accuracy) to the optimal sex-specific delta thresholds (90.3% accuracy), with 95.8% agreement between the two diagnostic methods. Serial logistic regressions revealed that delta hs-cTnT played a more predominant role in AMI prediction than its confounders, among which sex is more predictive of AMI (total effect coefficient 1.04) than age (total effect coefficient 0.05) and eGFR (total effect coefficient -0.008). CONCLUSIONS: The integrated prediction model incorporating confounding factors does not outperform hs-cTnT delta thresholds. Sex-specific hs-cTnT delta thresholds remain to provide the highest diagnostic accuracy.

Normative values for grip strength, gait speed, timed up and go, single leg balance, and chair rise derived from the Canadian longitudinal study on ageing.

BACKGROUND: decreased muscle strength and physical function often precede disability, nursing home admission, home care use and mortality in older adults. Normative values for commonly used physical performance-based tests are not widely available for older adults but are required for clinicians and researchers to easily identify individuals with low performance. OBJECTIVE: to develop normative values for grip strength, gait speed, timed up and go, single-leg balance and five-repetition chair rise tests in a large population-based sample of Canadians aged 45-85 years. METHODS: baseline data (2011-2015) from the Canadian Longitudinal Study on Ageing was used to estimate age- and sex-specific normative values for each of the physical tests. Participants were without disability or mobility limitation (no assistance with activities of daily living or use of mobility devices). RESULTS: of the 25,470 participants eligible for the analyses 48.6% (n = 12,369) were female with a mean age of 58.6 ± 9.5 years. Sex-specific 5th, 10th, 20th, 50th, 80th, 90th and 95th percentile values for each physical performance-based test were estimated. Cross-validation (n = 100 repetitions) with a 30% holdout sample was used to evaluate model fit. CONCLUSIONS: the normative values developed in this paper can be used in clinical and research settings to identify individuals with low performance relative to their peers of the same age and sex. Interventions targeting these at-risk individuals including physical activity can prevent or delay mobility disability and the resulting cascade of increasing care requirements, health care costs and mortality.

Prevalence, Incidence, and Predictors of Self-reported Swallowing Difficulties in Community-Dwelling Adults: A Population-Based Study from the Canadian Longitudinal Study on Aging (CLSA).

There is a paucity of evidence from population-based studies identifying prevalence and incidence of dysphagia, as well as health and sociodemographic risk factors that may contribute to its development. As such, the current study aimed to determine prevalence, incidence, and associated predictors of dysphagia in adults. The Canadian Longitudinal Study on Aging is a nationally representative population study that follows 51,338 Canadians over 45 years of age. Biological, medical, psychological, social, lifestyle and economic data are collected. A secondary analysis of the data was conducted to determine prevalence, incidence, and the predictors of self-reported swallowing difficulty in adults between 45 and 85 years of age. Rates of swallowing difficulty by demographic risk factor, as well as lifestyle and health factors were analyzed using descriptive statistics. Associations between lifestyle and health variables with dysphagia were tested using Chi-square tests or t tests, as appropriate. Logistic regression was used to determine the predictors of self-reported swallowing difficulties. Overall prevalence of self-reported swallowing difficulties in adults over the age of 45 was 10.6% and increased to 13.7% after 3 years. Significant differences (p < 0.001) in self-reported swallowing difficulty at baseline were apparent across smoking status, requiring help to prepare meals, life satisfaction, social participation, all disease categories except dementia, number of medications, cognition, oral health status, and frailty. Incidence of dysphagia was 8.6%. Regression analyses suggested the following independent predictors of reports of swallowing difficulty: older age; non-white ethnicity; female sex; poor oral health; malnutrition; and frailty. These predictors should be carefully considered to ensure we are screening at-risk populations. Social determinants of health, such as ethnicity, must also be considered to ensure equitable care across the population.

Associations between lung function and physical and cognitive health in the Canadian Longitudinal Study on Aging (CLSA): A cross-sectional study from a multicenter national cohort.

BACKGROUND: Low lung function is associated with high mortality and adverse cardiopulmonary outcomes. Less is known of its association with broader health indices such as self-reported respiratory symptoms, perceived general health, and cognitive and physical performance. The present study seeks to address the association between forced expiratory volume in 1 second (FEV1), an indicator of lung function, with broad markers of general health, relevant to aging trajectory in the general population. METHODS AND FINDINGS: From the Canadian general population, 22,822 adults (58% females, mean age 58.8 years [standard deviation (SD) 9.6]) were enrolled from the community between June 2012 and April 2015 from 11 Canadian cities and 7 provinces. Mixed effects regression was used to assess the cross-sectional relationship between FEV1 with self-reported respiratory symptoms, perceived poor general health, and cognitive and physical performance. All associations were adjusted for age, sex, body mass index (BMI), education, smoking status, and self-reported comorbidities and expressed as adjusted odds ratios (aORs). Based on the Global Lung Function Initiative (GLI) reference values, 38% (n = 8,626) had normal FEV1 (z-scores >0), 37% (n = 8,514) mild (z-score 0 to > -1 SD), 19% (n = 4,353) moderate (z-score -1 to > -2 SD), and 6% (n = 1,329) severely low FEV1 (z-score = < -2 SD). There was a graded association between lower FEV1 with higher aOR [95% CI] of self-reported moderate to severe respiratory symptoms (mild FEV1 1.09 [0.99 to 1.20] p = 0.08, moderate 1.45 [1.28 to 1.63] p < 0.001, and severe 2.67 [2.21 to 3.23] p < 0.001]), perceived poor health (mild 1.07 [0.9 to 1.27] p = 0.45, moderate 1.48 [1.24 to 1.78] p = <0.001, and severe 1.82 [1.42 to 2.33] p < 0.001]), and impaired cognitive performance (mild 1.03 [0.95 to 1.12] p = 0.41, moderate 1.16 [1.04 to 1.28] p < 0.001, and severe 1.40 [1.19 to 1.64] p < 0.001]). Similar graded association was observed between lower FEV1 with lower physical performance on gait speed, Timed Up and Go (TUG) test, standing balance, and handgrip strength. These associations were consistent across different strata by age, sex, tobacco smoking, obstructive, and nonobstructive impairment on spirometry. A limitation of the current study is the observational nature of these findings and that causality cannot be inferred. CONCLUSIONS: We observed graded associations between lower FEV1 with higher odds of disabling respiratory symptoms, perceived poor general health, and lower cognitive and physical performance. These findings support the broader implications of measured lung function on general health and aging trajectory.

Age-appropriate BMI cut-points for cardiometabolic health risk: a cross-sectional analysis of the Canadian Longitudinal Study on Aging.

OBJECTIVES: Body composition changes that occur with aging pose unique health risks to older adults. The current World Health Organization (WHO) body mass index (BMI) cut-points may not accurately reflect health risks in older adults (65+). Prior findings suggest those classified as overweight may be conferred survival advantages. This study aims to define age-specific BMI cut-points for adults (45-64, 65-74, and 75-85 years) associated with cardiometabolic outcomes, and compare the performance of these thresholds to the WHO BMI thresholds using cardiometabolic conditions and frailty as outcomes. METHODS: Using baseline data from the comprehensive cohort of the Canadian Longitudinal Study on Aging (N = 30,097), a classification and regression tree cross-sectional analysis was conducted to derive age-specific BMI cut-points based on cardiometabolic health risk. The area under the receiver operating curve (AUC), sensitivity, and specificity were estimated. Agreement with waist circumference was conducted. RESULTS: For older adults (65-74 and 75+ years old), the BMI threshold for identifying overweight increased to 26.9 and 26.6, respectively, from the WHO definition of 25.0 kg/m2. For obesity, the thresholds were revised to 29.0 and 30.9, respectively, from 30.0. The largest improvements to AUC occurred in older adults (65+). Across all age-sex stratifications, the new overweight threshold demonstrated lower sensitivity and higher specificity compared to the traditional threshold. Age-specific BMI thresholds demonstrated higher agreement with waist circumference for some age-sex stratifications and poor performance with hearing. CONCLUSIONS: Age-appropriate BMI thresholds for older adults may improve classification by health risk compared to standard WHO cut-points. A higher overweight threshold but lower obesity cut-points may be best suited to this demographic.

Sex-Specific Absolute Delta Thresholds for High-Sensitivity Cardiac Troponin T.

BACKGROUND: Sex differences in high-sensitivity cardiac troponin (hs-cTn) concentrations from healthy populations have led to the establishment of sex-specific upper reference limits for hs-cTn assays. This study assessed the performance of sex-specific delta (i.e., changes in concentrations) thresholds for the hs-cTnT assay for ruling in acute myocardial infarction (AMI) in different emergency department (ED) populations. METHODS: This retrospective study consisted of 2 cohorts (Cohort 1 derivation and Cohort 2 validation). Cohort 1 consisted of 18 056 ED patients who had serial hs-cTnT measured using a 0-h/3-h algorithm at a US medical center, with Cohort 2 consisting of 1137 ED patients with 0-h/3-h sampling at a Canadian medical center. The primary outcome was AMI diagnosis with sex-specific deltas derived based on the Youden index and specificity estimates (i.e., ≥90%) in Cohort 1 and validated in Cohort 2. RESULTS: In Cohort 1, 42% of all patients had 0-h hs-cTnT above the sex-specific 99th percentile. Males had higher 0-h hs-cTnT (median 17 ng/L) and absolute deltas (median 2 ng/L) than females (0-h median 11 ng/L, P < 0.0001; deltas median 1 ng/L, P < 0.0001) in non-AMI patients but not in patients with AMI. For ruling in AMI, the sex-specific delta thresholds based on 90% specificity (14 ng/L for males, 11 ng/L for females) performed best and resulted in 91% diagnostic accuracy in both males and females. The sex-specific delta thresholds yielding high specificity estimates were confirmed in the validation data set. CONCLUSIONS: Sex-specific absolute delta thresholds can be used to rule in AMI and are robust across different study populations.

The correlation between multiple congenital anomalies hypotonia seizures syndrome 2 and PIGA: a case of novel PIGA germline variant and literature review.

BACKGROUND: PIGA (PIG class A) gene codes for the PIG-A protein, which is a catalytic subunit of GPI-GlcNAc transferase. GPI-anchored proteins play an important role in the metabolism of mammals. Somatic variants of PIGA genes in bone marrow hematopoietic stem cells often result in paroxysmal nocturnal haemoglobinuria, and the germline PIGA variants cause multiple congenital anomalies hypotonia seizures syndrome 2 (MCAHS2) because of glycosylphosphatidylinositol metabolic abnormalities. METHODS: Whole exome sequencing was performed on peripheral blood sample of the patient with MCAHS2. A novel germline PIGA variant was found, and Sanger sequencing was performed as verification for the variant. After that, we used the keywords to retrieve relevant reports and provided a literature review. RESULTS: A novel hemizygous germline PIGA variant (NM_002641.3:c.971G > A) at exon4 was identified through whole exome sequencing. And it was a highly probable pathogenic variant. Sanger sequencing yielded consistent results. The missense variant cause change of p.(Cys324Tyr) in the transcription product according to the predicted outcomes. CONCLUSION: We reported a case of MCAHS2 caused by a novel PIGA variant. Following a review of the literature, we suggested that MCAHS2 should be considered as a disorder spectrum consisting of core symptoms, multi-system impairment, and premature death. The core symptoms include hypotonia, psychomotor delay, epilepsy (intractable epilepsy mostly) and early death. Core symptoms nearly happened to almost all patients. Meanwhile, MCAHS2 involves a wide range of organ and system impairments with changeable form.

Associations of Adverse Childhood Experiences with Frailty in Older Adults: A Cross-Sectional Analysis of Data from the Canadian Longitudinal Study on Aging.

INTRODUCTION: Frailty in older adults, characterized by a decline in multiple physiological systems and increasing vulnerability to loss of independence, disability, and death, is a public health priority in developed countries. Etiology of frailty extends across the lifespan and may begin in early life, but empirical evidence for this association is scarce. In this study, we examined whether adverse childhood experiences (ACEs) are associated with frailty in later life. METHODS: We conducted a cross-sectional analysis of data for a population-based sample of 27,748 adults aged 45-85 years from the Canadian Longitudinal Study on Aging. The frailty index (FI) was computed with 76 health-related characteristics of physical and cognitive performance, self-rated health, chronic conditions, visual and hearing ability, activities of daily living, and well-being. Self-reported exposure to ACEs included physical, emotional, and sexual abuse, neglect, and witnessing intimate partner violence prior age of 16 and parental death, divorce, and living with a family member with mental illness prior age of 18. Generalized linear regression models with gamma error distribution and identity link function, adjusted for age and sex, were used to examine associations of each ACE type and the number of ACE types (0, 1, 2, or 3+) reported by an individual with FI. All models were adjusted for income, education, smoking, and alcohol consumption in sensitivity analysis. RESULTS: Individuals exposed to ACEs had elevated levels of FI (mean = 0.13, SD = 0.09) than those unexposed, with the largest difference observed for neglect (B [95% CI]: 0.05 [0.04, 0.06]) and the smallest for parental death and divorce (0.015 [0.01,0.02]). The ACE count was associated with frailty in a graded manner, with the FI difference reaching 0.04 [0.037, 0.044] for participants exposed to 3+ ACE types. The association between ACEs and frailty tended to be stronger for women than men and for men aged 45-64 years than older men. CONCLUSIONS: Our study supports previous studies showing that exposure to ACEs is associated with frailty in adults. Our findings suggest that screening for ACEs involving childhood maltreatment may be useful for identifying individuals at risk of frailty and prevention of ACEs may have long-term benefits for healthy aging.

T1R3 homomeric sweet taste receptor negatively regulates insulin-induced glucose transport through Gαs-mediated microtubules disassembly in 3T3-L1 adipocytes.

T1R3 is a class C G protein-coupled receptor family member that forms heterodimeric umami and sweet taste receptors with T1R1 and T1R2, respectively, in the taste cells of taste buds. T1R3 is expressed in 3T3-L1 cells in homomeric form and negatively regulates adipogenesis in a Gαs-dependent but cAMP-independent manner. Although T1R3 expression is markedly upregulated during adipogenesis, its physiological role in mature adipocytes remains obscure. Here, we show that stimulation of T1R3 with sucralose or saccharin induces microtubule disassembly in differentiated 3T3-L1 adipocytes. The effect was reproduced by treatment with cholera toxin or isoproterenol but not with forskolin. Treatment with sucralose or saccharin for 3 h inhibited insulin-stimulated glucose uptake by 32% and 45% in differentiated adipocytes, respectively, similar to the inhibitory effect of nocodazole (by 33%). Isoproterenol treatment inhibited insulin-stimulated glucose transport by 26%, whereas sucralose did not affect the intrinsic activity of the glucose transporter, indicating that it inhibited insulin-induced GLUT4 translocation to the plasma membrane. Immunostaining analysis showed that insulin-stimulated GLUT4 accumulation on the plasma membrane was abrogated in sucralose-treated cells, in association with depolymerization of microtubules. Sucralose-mediated inhibition of GLUT4 translocation was reversed by the overexpression of dominant-negative Gαs (Gαs-G226A) or knockdown of Gαs. Additionally, membrane fractionation analysis showed that sucralose treatment reduced GLUT4 levels in the plasma membrane fraction from insulin-stimulated adipocytes. We have identified a novel non-gustatory role for homomeric T1R3 in adipocytes, and activation of the T1R3 receptor negatively regulates insulin action of glucose transport via Gαs-dependent microtubule disassembly.

What is the impact of a novel DEPDC5 variant on an infant with focal epilepsy: a case report.

BACKGROUND: Variants in the DEPDC5 have been proved to be main cause of not only various dominant familial focal epilepsies, but also sporadic focal epilepsies. In the present study, a novel variant in DEPDC5 was detected in the patient with focal epilepsy and his healthy father. We aimed to analyze the pathogenic DEPDC5 variant in the small family of three. CASE PRESENTATION: A 5-month-old male infant presented with focal epilepsy. Whole exome sequencing identified a novel heterozygous variant c.1696delC (p.Gln566fs) in DEPDC5, confirmed by Sanger sequencing. The variant was inherited from healthy father. CONCLUSIONS: Our study expands the spectrum of DEPDC5 variants. Moreover, We discuss the relation between the low penetrance of DEPDC5 and the relatively high morbidity rate of DEPDC5-related sporadic focal epilepsy. Besides, due to interfamilial phenotypic and genetic heterogeneity, we speculate the prevalence of familial focal epilepsy with variable foci might be underestimated in such small families. We emphasize the importance of gene detection in patients with sporadic epilepsy of unknown etiology, as well as their family members. It can identify causative mutations, thus providing help to clinicians in making a definitive diagnosis.

Biological sex, not reproductive cycle, influences peripheral blood immune cell prevalence in mice.

KEY POINTS: Traditionally the female sex, compared with the male sex, has been perceived as having greater variability in many physiological traits, including within the immune system. We investigated effects of biological sex and the female reproductive cycle on numbers of circulating leukocytes in C57BL/6J mice. We show that biological sex, but not female reproductive cyclicity, has a significant effect on peripheral blood immune cell prevalence and variability, and that sex differences were not consistent amongst common inbred laboratory mouse strains. We found that male C57BL/6J mice, compared with female mice, have greater variability in peripheral blood immunophenotype, and that this was influenced by body weight. We created summary tables for researchers to facilitate experiment planning and sample size calculations for peripheral immune cells that consider the effects of biological sex. ABSTRACT: Immunophenotyping (i.e. quantifying the number and types of circulating leukocytes) is used to characterize immune changes during health and disease, and in response to pharmacological and other interventions. Despite the importance of biological sex in immune function, there is considerable uncertainty amongst researchers as to the extent to which biological sex or the female reproductive cycle influence blood immunophenotype. We quantified circulating leukocytes by multicolour flow cytometry in young C57BL/6J mice and assessed the effects of the reproductive cycle, biological sex, and other experimental and biological factors on data variability. We found that there are no significant effects of the female reproductive cycle on the prevalence of peripheral blood B cells, NK cells, CD4+ T cells, CD8+ T cells, monocytes, or neutrophils. Immunophenotype composition and variability do not significantly change between stages of the female reproductive cycle. There are, however, sex-specific differences in immune cell prevalence, with fewer monocytes, neutrophils, and NK cells in female mice. Surprisingly, immunophenotype is more variable in male mice, and weight is a significant contributing factor. We provide tools for researchers to perform a priori sample size calculations for two-group and factorial analyses. We show that immunophenotype varies between inbred mouse strains, and that using equal sample sizes of male and female mice is not always appropriate for within-sex evaluations of immune cell populations in peripheral blood.

The combined effect of behavioural risk factors on disability in aging adults from the Canadian Longitudinal Study on Aging (CLSA).

The objective of this study was to explore how behavioural risk factors (smoking, physical activity, and nutrition) cluster together and assess how clusters of behavioural risk factors are associated with functional disability by age and sex at the individual and population level. We used currently available baseline cross-sectional data from the Canadian Longitudinal Study on Aging (CLSA). The CLSA is a national, population-based longitudinal study established to understand and examine health of an aging population. This study included 51,338 Canadian men and women aged 45 to 85 years residing in the community in 10 Canadian provinces. Behavioural risk factors included smoking, physical activity, and nutrition. The main outcome used in the study was functional disability, which was assessed using a questionnaire adapted from the Older Americans Resources and Services Multidimensional Assessment Questionnaire. In this analyses of unique combinations of the risk factors of smoking, physical activity, and nutritional risk, the magnitude of the association of the behavioural risk factors with functional disability was dependent on which risk factors were included and differed by age and sex strata. Of the risk factors, physical activity accounted for between 70% to 90% of the total population level risk in individuals with all three risk factors, suggesting it is a key driver of the population burden of disability. Together, these results show that considering unique clusters of risk factors, as well as age and sex, is essential for tailoring public health strategies to reduce the burden of disability among aging populations.

Preconditioning with Cathodal High-Definition Transcranial Direct Current Stimulation Sensitizes the Primary Motor Cortex to Subsequent Intermittent Theta Burst Stimulation.

Noninvasive brain stimulation techniques such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) can induce long-term potentiation-like facilitation, but whether the combination of TMS and tDCS has additive effects is unclear. To address this issue, in this randomized crossover study, we investigated the effect of preconditioning with cathodal high-definition (HD) tDCS on intermittent theta burst stimulation- (iTBS-) induced plasticity in the left motor cortex. A total of 24 healthy volunteers received preconditioning with cathodal HD-tDCS or sham intervention prior to iTBS in a random order with a washout period of 1 week. The amplitude of motor evoked potentials (MEPs) was measured at baseline and at several time points (5, 10, 15, and 30 min) after iTBS to determine the effects of the intervention on cortical plasticity. Preconditioning with cathodal HD-tDCS followed by iTBS showed a greater increase in MEP amplitude than sham cathodal HD-tDCS preconditioning and iTBS at each time postintervention point, with longer-lasting after-effects on cortical excitability. These results demonstrate that preintervention with cathodal HD-tDCS primes the motor cortex for long-term potentiation induced by iTBS and is a potential strategy for improving the clinical outcome to guide therapeutic decisions.

A meta-analysis on genetic associations between Transcription Factor 7 Like 2 polymorphisms and type 2 diabetes mellitus.

BACKGROUND: Some previous studies already explored associations of Transcription Factor 7 Like 2 (TCF7L2) polymorphisms with type 2 diabetes mellitus (T2DM), with conflicting findings. Here, we aimed to better analyze the relationship between TCF7L2 polymorphisms and T2DM in a larger combined population by performing a meta-analysis. METHODS: We searched Pubmed, Embase, Web of Science and CNKI for related articles. We calculated odds ratio (OR) and 95% confidence interval (CI) to estimate whether there are genetic associations between TCF7L2 polymorphisms and T2DM. RESULTS: Totally 42 studies were included for this meta-analysis. The meta-analysis results demonstrated that TCF7L2 rs4506565, rs7901695, rs11196205 and rs12255372 polymorphisms were all significantly associated with susceptibility to T2DM in general population. Further subgroup analyses revealed similar significant findings in both Asians and Caucasians. CONCLUSIONS: Our findings supported that these TCF7L2 polymorphisms could be used to identify individuals at high risk of developing T2DM.

A Comparison of AGREE and RIGHT: which Clinical Practice Guideline Reporting Checklist Should Be Followed by Guideline Developers?

BACKGROUND: A clinical practice guideline (CPG) reporting checklist is used to assist CPG developers in recording what content should be provided in a CPG report. Recently, two checklists have become available on the Enhancing the QUAlity and Transparency Of health Research Network website: AGREE (Appraisal of Guidelines, Research and Evaluation) published in 2016 and RIGHT (Reporting Items for practice Guidelines in HealThcare) published in 2017. The objective of this study was to describe the advantages and disadvantages of these two CPG reporting checklists. METHODS: Two epidemiologists who lacked experience using both AGREE and RIGHT but were familiar with evidence-based medicine methodology independently compared AGREE with RIGHT on an item-by-item basis. Their assessments were compiled on a pre-designed data form and any disagreements were resolved through discussion. Three other co-authors independently compared AGREE with RIGHT and decided if they agreed with the results of comparison of the two CPG reporting checklists from the first two co-authors. Finally, another co-author reviewed the comparison results to ensure that the description was clear and understandable. RESULTS: The following six relationships between the two checklists were observed: (1) 11 items from AGREE completely matched with 12 items from RIGHT; (2) four items were listed in AGREE only; (3) 12 items were listed in RIGHT only; (4) three items in AGREE were partially covered by three items in RIGHT; (5) six items in RIGHT were partially covered by three items in AGREE; and (6) two items intersected across AGREE and RIGHT. Based on the comparison results, the potential impact analysis of selecting either checklist is described. DISCUSSION: We recommend that CPG developers use either AGREE plus items unique to RIGHT or RIGHT plus items unique to AGREE.

Physical Function and Frailty for Predicting Adverse Outcomes in Older Primary Care Patients.

OBJECTIVE: To explore the predictive ability of the Short Physical Performance Battery (SPPB), Late Life Function and Disability Instrument-Function component (LLFDI-function) and frailty phenotype, for falls, hospitalizations, emergency department (ED) visits, and low self-rated health (SRH) over 1 and 2 years in older adults. DESIGN: Secondary analysis of data from a longitudinal study, the Boston Rehabilitative Impairment Study of the Elderly. SETTING: Primary care. PARTICIPANTS: Adults 65 years and older at risk for disability who completed ≥1 follow-up call (N=391). INTERVENTIONS: None. MAIN OUTCOME MEASURES: We computed separate logistic regression models using the SPPB, LLFDI-function, and frailty phenotype as independent variables and falls, hospitalizations, ED visits, and SRH over 1 and 2 years as dependent variables. Receiver operating characteristic curves were constructed and the areas under the curves calculated. RESULTS: Participants had a mean age of 76.5±7.1 years. The SPPB, LLFDI-function, and frailty phenotype all predicted hospitalizations and low SRH over a 1- and 2-year timeframe (odds ratio [OR] min-max, 1.35-1.51 and 1.67-3.07, respectively). Over 2 years, the SPPB predicted ED visits (OR, 1.28), and the LLFDI-function predicted falls (OR, 1.31). The LLFDI-function predicted low SRH better than the frailty phenotype over 1 year. There were no differences between the measures for any of the other outcomes. CONCLUSIONS: The SPPB, LLFDI-function, and frailty phenotype had similar accuracy for predicting falls, hospitalizations, ED visits, and low SRH over 1 and 2 years among older primary care patients at risk for disability. As a result, when considering the optimal screening tool for older adults, the choice between a measure of function and frailty may ultimately depend on clinical preference and context.