Single cell RNA sequencing reveals mesenchymal heterogeneity and critical functions of Cd271 in tooth development.

BACKGROUND: Accumulating evidence suggests that the maxillary process, to which cranial crest cells migrate, is essential to tooth development. Emerging studies indicate that Cd271 plays an essential role in odontogenesis. However, the underlying mechanisms have yet to be elucidated. AIM: To establish the functionally heterogeneous population in the maxillary process, elucidate the effects of Cd271 deficiency on gene expression differences. METHODS: p75NTR knockout (Cd271-/-) mice (from American Jackson laboratory) were used to collect the maxillofacial process tissue of p75NTR knockout mice, and the wild-type maxillofacial process of the same pregnant mouse wild was used as control. After single cell suspension, the cDNA was prepared by loading the single cell suspension into the 10x Genomics Chromium system to be sequenced by NovaSeq6000 sequencing system. Finally, the sequencing data in Fastq format were obtained. The FastQC software is used to evaluate the quality of data and CellRanger analyzed the data. The gene expression matrix is read by R software, and Seurat is used to control and standardize the data, reduce the dimension and cluster. We search for marker genes for subgroup annotation by consulting literature and database; explore the effect of p75NTR knockout on mesenchymal stem cells (MSCs) gene expression and cell proportion by cell subgrouping, differential gene analysis, enrichment analysis and protein-protein interaction network analysis; understand the interaction between MSCs cells and the differentiation trajectory and gene change characteristics of p75NTR knockout MSCs by cell communication analysis and pseudo-time analysis. Last we verified the findings single cell sequencing in vitro. RESULTS: We identified 21 cell clusters, and we re-clustered these into three subclusters. Importantly, we revealed the cell-cell communication networks between clusters. We clarified that Cd271 was significantly associated with the regulation of mineralization. CONCLUSION: This study provides comprehensive mechanistic insights into the maxillary- process-derived MSCs and demonstrates that Cd271 is significantly associated with the odontogenesis in mesenchymal populations.

Radon exposure and risk of neurodegenerative diseases among male miners in Ontario, Canada: A cohort study.

BACKGROUND: Environmental radon has been examined as a risk factor for neurodegenerative diseases in a small number of previous studies, but the findings have been inconsistent. This study aims to investigate the association between occupational radon exposure and neurodegenerative disease in a cohort of male miners with work experience in multiple ore types in Ontario, Canada. METHODS: Radon exposure (1915-1988) was assessed using two job-exposure matrices (JEM) constructed from using historical records for 34,536 Ontario male miners. Neurodegenerative outcomes were ascertained between 1992 and 2018. Poisson regression models were used to estimate incidence rate ratios (RR) and 95% confidence intervals (CI) between cumulative radon exposure in working level months (WLM) and each neurodegenerative outcome. RESULTS: Levels of cumulative radon exposure showed variability among cohort members with a mean of 7.5 WLM (standard deviation 24.4). Miners in uranium mines or underground jobs had higher levels and more variability in exposure than workers in non-uranium work or surface jobs. Compared to the reference group (radon < 1 WLM), increased rates of Alzheimer's (RR 1.23, 95% CI 1.05-1.45) and Parkinson's disease (RR 1.43, 95% CI 1.08-1.89) were observed among workers with >1-5 WLM and >5-10 WLM, respectively, but not among higher exposed workers (>10 WLM). CONCLUSION: This study did not observe a positive monotonic dose-response relationship between cumulative radon exposure and Alzheimer's or Parkinson's disease in Ontario mining workers. There was no association observed with motor neuron disease.

Efficacy and Safety of Thermal Ablation for Treating Lymph Node Metastasis From Papillary Thyroid Carcinoma: A Systematic Review and Meta-Analysis.

Objective: To evaluate the efficacy and safety of thermal ablation, including radiofrequency ablation (RFA), microwave ablation (MVA), and laser ablation (LA), for treating lymph node metastasis (LNM) from papillary thyroid carcinoma (PTC). Design and Methods: PubMed and EMBASE were searched for studies reporting the efficacy and safety of thermal ablation for treating LNM in PTC. After selecting the relevant literature (including 11 papers, 208 patients, 412 lymph nodes), the QUADAS-2 tool was used to evaluate its quality. Then, both the fixed-effects and random-effects models combined with subgroup analysis were used to calculate data on volume changes in metastatic lymph nodes and changes in serum thyroglobulin (Tg) levels. We pooled the proportion of major and overall complication rates and complete disappearance rates and used subgroup forest plots and funnel plots for visual representation. Because of publication bias, we also performed a trim-and-filled model for correction. The rate of recurrence and distant metastasis with ablated details were pooled. Results: In the 11 articles (208 patients and 412 diseased lymph nodes), all thermal ablation methods showed effectiveness in reducing lymph node volume (P = 0.02) and serum Tg levels (P < 0.01) which showed no between-group difference. The pooled proportion of major complications was 0%(95% CI: -0.14; 0.15, P = 1) and the overall complication rate was 5% (95% CI: -0.09; 0.20, P = 1), which revealed no significant difference among modalities. The pooled proportion of the complete disappearance rate was 82% (95% CI: 0.43; 0.96, P < 0.01) and the data with statistical significance which contains RFA and LA showed complete disappearance rate was 59% and 81% respectively. Conclusion: All thermal ablation methods, including RFA, MWA, and LA, were effective and safe for treating LNM in PTC and were especially suitable for nonsurgical patients. Besides, subgroup analysis showed no significant difference, except for LA is better than RFA in complete disappearance rate.

Aluminum dust exposure and risk of neurodegenerative diseases in a cohort of male miners in Ontario, Canada.

OBJECTIVES: We estimated associations between respirable aluminum exposure through McIntyre Powder (MP), a fine-sized aluminum and aluminum compound powder, and neurological disease in a retrospective cohort of mining workers from Ontario, Canada. Outcomes included Alzheimer's disease, Alzheimer's with other dementias, Parkinson's disease, parkinsonism, and motor neuron disease. METHODS: The cohort was created by linking a database of mining workers' work history to healthcare records. This analysis included 36 826 male miners potentially exposed to MP between 1943 and 1979, followed up for disease diagnosis between 1992 and 2018. Exposure was assessed using two approaches, self-reported and historical records. Neurological diseases were ascertained using physician billing and hospital discharge records. Poisson regression models were used to estimate associations between MP exposure and neurological outcomes using incidence rate ratios (RR) and 95% confidence intervals (95% CI). RESULTS: Exposure to self-reported MP was associated with an elevated incidence rate of Parkinson's disease (RR 1.34, 95% CI 1.14-1.57). The rate of Parkinson's disease appeared to increase with the duration of exposure assessed by historical records. Having ever been exposed to MP was positively associated with an elevated rate of Alzheimer's with other dementias (RR 1.12, 95% CI 1.06-1.19) but not Alzheimer's disease alone. CONCLUSION: This study found that miners who were exposed to MP (respirable aluminum) had elevated rates of Parkinson's disease. The rate of Parkinson's disease appeared to increase with the duration of exposure assessed by historical records.

Neurodegenerative diseases among miners in Ontario, Canada, using a linked cohort.

OBJECTIVES: We examined employment in mining occupations and industries and its association with neurological disease incidence in a linkage cohort from Ontario, Canada. Outcomes included Alzheimer's disease (alone and with other dementias), Parkinson's disease, parkinsonism, motor neuron disease and amyotrophic lateral sclerosis (ALS). METHODS: The Occupational Disease Surveillance System cohort was created by linking workers' compensation data and healthcare usage records. This analysis included over 1.1 million male workers, followed between 1999 and 2016. Neurological diseases were ascertained using physician billing and hospital discharge records. Adjusted Poisson regression models were used to estimate incidence rate ratios (RR) comparing mining to non-mining workers overall and by ore (industry) and occupation group. RESULTS: Suggested elevations in incidence rates were observed for ALS among workers of metal mines (RR 2.21, 95% CI 1.04 to 4.69) and for motor neuron disease among those employed in mining occupations within metal mining industries (RR 1.96, 95% CI 1.01 to 3.79), though these were based on relatively few cases. In miscellaneous metal mines, workers who held mining occupations had an elevated rate of Alzheimer's disease (RR 1.27, 95% CI 0.92 to 1.77). Parkinson's disease rate was elevated among workers with rock and soil drilling occupations (RR 1.60, 95% CI 1.04 to 2.45). CONCLUSIONS: Mining hazards may be associated with elevated rates of neurodegenerative diseases among workers in mining occupations and industries. More work is needed to better understand mining exposures and their associations with neurodegenerative diseases.

Trunk Posture Exposure Patterns among Prairie Ranch and Grain Farmers.

Objectives: Low back disorders (LBD) are the most common musculoskeletal disorder among farmers, and awkward trunk postures such as repetitive bending are often cited as a contributor. However, it is not clear whether trends of increasing mechanization in agriculture may be impacting the requirement for trunk-intensive tasks. This study compared the patterns of working trunk posture among prairie farmers during both machine-intensive and non-intensive work days.Methods: Forty-nine adult farm workers from 22 farms participated in this study. Individual and farm characteristics were documented via questionnaire. Trunk angles and velocities were measured with an I2M inertial sensor placed on the chest. Participants completed electronic posture assessments during up to three regular work days throughout the growing season for a total of 91 electronic posture measurements. Forward and lateral trunk bending patterns were expressed in three domains: magnitude, duration, and frequency.Results: Working tasks were categorized into driving, manual, and mixed. Driving was the most commonly measured task (52% of work days), and mixed tasks the least (12%). Both 90th percentile trunk flexion-extension angles and velocities were significantly higher for manual as compared to driving tasks. Participants spent 38% of their working time in trunk forward flexion ≥ 20°, which, according to previous epidemiological studies, may increase their risk for LBD.Conclusion: The directly-measured trunk posture exposure patterns in this study suggest that machinery-intensive workdays result in less awkward trunk posture and lower velocities. Increasing mechanization invites more research on the exposures associated with machinery operation and increasing automation.

Musculoskeletal discomfort among Canadian bovine practitioners: Prevalence, impact on work, and perception of physically demanding tasks.

Musculoskeletal discomfort (MSD) is prevalent in large animal veterinarians but little research has been conducted on prevalence of MSD and its impact among Canadian bovine veterinarians. This 2017 survey targeted practicing and retired members of the Western Canadian Association of Bovine Practitioners, and adapted the Nordic Musculoskeletal Questionnaire to quantify MSD prevalence. Open-ended questions were used to determine the impact of MSD on work and to determine what were perceived to be the most physically demanding tasks. The survey response rate was 51.4% (133/259). Prevalence of MSD was high, with 12-month and lifetime rates of 89.5% and 96.9%, respectively. Obstetrical procedures, rectal examinations, and bull semen collections were reported as the 3 most physically strenuous tasks. The high MSD prevalence rates observed in the shoulder, neck, and lower back call for research on direct ergonomic assessments and work practice interventions for bovine veterinarians.

Inconfort musculo-squelettique parmi les praticiens bovins canadiens : prévalence, impact sur le travail et perception des tâches exigeantes sur le plan physique. L'inconfort musculo-squelettique (IMS) est prévalent chez les vétérinaires pour grands animaux mais peu de recherches ont été réalisées sur la prévalence de l'IMS et son impact parmi les vétérinaires bovins canadiens. Cette enquête de 2017 a ciblé les membres praticiens et retraités de la Western Canadian Association of Bovine Practitioners et a adapté le questionnaire nordique sur la santé musculo-squelettique pour quantifier la prévalence de l'IMS. Des questions à réponse libre ont été utilisées pour déterminer l'impact de l'IMS sur le travail et déterminer ce qui était perçu comme les tâches les plus exigeantes physiquement. Le taux de réponse a été de 51,4 % (133/259). La prévalence de l'IMS était élevée, avec des taux de 12 mois et d'une vie de 89,5 % et de 96,9 %, respectivement. Les interventions obstétriques, les examens rectaux et le prélèvement de sperme chez les taureaux étaient signalés comme les tâches les plus difficiles sur le plan physique. Des taux élevés de prévalence de l'IMS ont été observés dans les épaules, le cou et le bas du dos et nécessitent de la recherche sur les évaluations ergonomiques directes et des interventions pour les pratiques de travail des vétérinaires bovins.(Traduit par Isabelle Vallières).

Measurement properties of instruments assessing permanent functional impairment of the spine: a systematic review protocol.

INTRODUCTION: Permanent functional impairment (PFI) of the spine is a rating system used by compensation authorities, such as workers compensation boards, to establish an appropriate level of financial compensation for persistent loss of function. Determination of PFI of the spine is commonly based on the assessment of spinal movement combined with other measures of physical and functional impairments; however, the reliability and validity of the measurement instruments used for these evaluations have yet to be established. The aim of this study is to systematically review and synthesise the literature concerning measurement properties of the various and different instruments used for assessing PFI of the spine. METHODS: Three conceptual groups of terms (1) PFI, (2) spinal disorder and (3) measurement properties will be combined to search Medline, EMBASE, CINAHL, Web of Science, Scopus, PEDro, OTSeeker and Health and Safety Science Abstracts. We will examine peer-reviewed, full-text articles over the full available date range. Two reviewers will independently screen citations (title, abstract and full text) and perform data extraction. Included studies will be appraised as to their methodological quality using the COnsensus-based Standards for the selection of health Measurement INstruments criteria. Findings will be summarised and presented descriptively, with meta-analysis pursued as appropriate. ETHICS AND DISSEMINATION: This review will summarise the current level of evidence of measurement properties of instruments used for assessing PFI of the spine. Findings of this review may be applicable to clinicians, policy-makers, workers' compensation boards, other insurers and health and safety organisations. The findings will likely provide a foundation and direction for future research priorities for assessing spinal PFI. PROSPERO REGISTRATION NUMBER: CRD42017060390.

Predicting Whole-Body Vibration Exposure in Canadian Prairie Farmers.

Direct workplace whole-body vibration exposure assessment provides ecological validity for evaluating health risk in epidemiological studies, yet it is complex and expensive in practical applications. Exposure prediction modeling could be a cost-efficient alternative to directly assessing occupational vibration exposures. The objective of this study was to model directly measured whole-body vibration exposures with predictors from machinery, farm, and self-reported characteristics among Canadian prairies farmers. As per ISO 2631-1, whole-body vibration data were measured on the seat surface at three axes (x, y, z), then summarized into vector sums of the root-mean-squared (RMS) acceleration and the vibration dose value (VDV). All candidate predictors were obtained via questionnaires and onsite observations. A total of 87 whole-body vibration measurements were collected from 40 male farm workers located at 21 central Saskatchewan farms. Using log-transformed RMS and time-standardized VDV outcomes, modeling started from the bivariate analysis where predictors with P-values < 0.2 were considered eligible for multivariate analysis. With random effects of 'farm' and 'farmer', a series of mixed-effects models were constructed through the manual backward elimination method. Final models were internally validated by 1000 bootstrapped samples. The RMS model explained 47.7% of the variance in the directly measured RMS vector sum, with 42.7% obtained from five predictors of 'horsepower', 'transmission', 'vehicle year', 'jerk/jolt frequency', and 'seat bottom-out frequency', while the VDV model explained 19.5% of the variance in the directly measured VDV vector sum, with 11.6% described by the same five predictors as the RMS model. Predictive ability of the RMS model among 1000 bootstrapped samples can be anticipated to range from 14.3 to 69.1%, which may be considered adequate as exposure assessment tool for uses of epidemiological studies. The percentage of variance explained ranged from 0 to 40.5% for the VDV model, which is not robust and therefore likely not appropriate for use in survey-based exposure prediction. Whole-body vibration exposure modeling remains valuable, but is challenging in farming; the described model variance may increase with a more comprehensive list of candidate variables collected and quantified at machinery, farm, and farmer level. Predictors identified in the current and future models may provide a better understanding of how whole-body vibration exposure is modified, guide farmer's future decision on updating equipment, and allow for the development and initiation of interventions.

Whole-body vibration exposure of occupational horseback riding in agriculture: A ranching example.

BACKGROUND: Horse riding is common in many occupations; however, there is currently no research evaluating exposure to whole-body vibration and mechanical shock on horseback. METHODS: Whole-body vibration was measured on a cattle rancher during two 30 min horseback rides using a tri-axial accelerometer mounted on a western saddle. Vibration was summarized into standardized metrics, including the 8 hr equivalent root-mean-squared acceleration (A[8]) and the daily 4th power vibration dose value (VDV). The resulting exposures were compared to the exposure limit and action values provided by European Union Directive 2002/44/EC. RESULTS: The highest vibration for both rides was in the vertical axis, with average A(8) and VDV of 0.56 m/s2 and 26.24 m/s1.75 , respectively. The A(8) value indicated moderate risk while the VDV suggested high risk of harmful health effects. CONCLUSIONS: Exposure to whole-body vibration and mechanical shock during occupational horseback riding may pose deleterious health risks and increased susceptibility to low back pain. Am. J. Ind. Med. 60:215-220, 2017. © 2017 Wiley Periodicals, Inc.

Whole body vibration exposure patterns in Canadian prairie farmers.

Whole body vibration is a significant physical risk factor associated with low back pain. This study assessed farmers' exposure to whole body vibration on the Canadian prairies according to ISO 2631-1. Eighty-seven vibration measurements were collected with a triaxial accelerometer embedded in a rubber seat pad at the operator-seat interface of agricultural machinery, including tractors, combines, pickup trucks, grain trucks, sprayers, swathers, all-terrain vehicles, and skid steers. Whole body vibration was highest in the vertical axis, with a mean (range) frequency-weighted root mean squared acceleration of 0.43 m/s2 (0.19-1.06 m/s2). Mean crest factors exceeded 9 in all 3 axes, indicating high mechanical shock content. The vertical axis vibration dose value was 7.55 m/s1.75 (2.18-37.59 m/s1.75), with 41.4% of measurements within or above the health guidance caution zone. These high exposures in addition to an ageing agricultural workforce may increase health risks even further, particularly for the low back. Practitioner Summary: Agricultural workers are frequently exposed to whole body vibration while operating farm equipment, presenting a substantial risk to musculoskeletal health including the low back. Assessing vibration exposure is critical in promoting a safe occupational environment, and may inform interventions to reduce farmer's exposure to vibration.