Spinal and supraspinal motor control predictors of rate of torque development

During explosive movements and potentially injurious situations, the ability to rapidly generate torque is critical. Previous research has suggested that different phases of rate of torque development (RTD) are differentiately controlled. However, the extent to which supraspinal and spinal mechanisms predict RTD at different time intervals is unknown. RTD of the plantarflexors across various phases of contraction (i.e., 0–25, 0–50, 0–100, 0–150, 0–200, and 0–250 ms) was measured in 37 participants. The following predictor variables were also measured: (a) gain of the resting soleus H‐reflex recruitment curve; (b) gain of the resting homonymous post‐activation depression recruitment curve; (c) gain of the GABAergic presynaptic inhibition recruitment curve; (d) the level of postsynaptic recurrent inhibition at rest; (e) level of supraspinal drive assessed by measuring V waves; and (f) the gain of the resting soleus M wave. Stepwise regression analyses were used to determine which variables significantly predicted allometrically scaled RTD. The analyses indicated that supraspinal drive was the dominant predictor of RTD across all phases. Additionally, recurrent inhibition predicted RTD in all of the time intervals except 0–150 ms. These results demonstrate the importance of supraspinal drive and recurrent inhibition to RTD.     

Elastic properties of Thiel‐embalmed human ankle tendon and ligament

Thiel embalming is recommended as an alternative to formalin‐based embalming because it preserves tissue elasticity, color, and flexibility in the long term, with low infection and toxicity risk. The degree to which Thiel embalming preserves elasticity has so far been assessed mainly by subjective scoring, with little quantitative verification. The aim of this study is to quantify the effect of Thiel embalming on the elastic properties of human ankle tendons and ligament. Biomechanical tensile tests were carried out on six Thiel‐embalmed samples each of the peroneus longus, peroneus brevis, and calcaneal tendons, and the calcaneofibular ligament, with strain rates of 0.25%s^?1, 2%s^?1, and 8%s^?1. The stress?strain relationship was calculated from the force‐extension response with cross‐sectional area and gauge length. Young's modulus was determined from the stress?strain curve. The results showed that the tendon and ligament elasticity were lower after Thiel embalming than the literature values for fresh nonembalmed tendons and ligament. The biomechanical tensile test showed that the measured elasticity of Thiel‐embalmed tendons and ligaments increased with the strain rate. The Thiel embalming method is useful for preserving human ankle tendons and ligaments for anatomy and surgery teaching and research, but users need to be aware of its softening effects. The method retains the mechanical strain rate effect on tendons and ligament. Clin. Anat. 28:917–924, 2015. © 2015 Wiley Periodicals, Inc.     

Reoperation rates and risk factors for revision 4 years after dynamic stabilization of the lumbar spine

Background Context

The concept of dynamic stabilization (DS) of the lumbar spine for treatment of degenerative instability has been introduced almost two decades ago. Dynamic stabilization follows the principle of controlling movement in the coronal plane by providing load transfer of the spinal segment without fusion and, at the same time, reducing side effects such as adjacent segment disease (ASD). So far, only little is known about revision rates after DS due to ASD and screw loosening (SL).

淋巴结转移率对甲状腺乳头状癌术后131 I治疗临床转归的预测价值

目的分析淋巴结转移率对甲状腺乳头状癌(PTC)患者手术后碘131(131 I)清除残留甲状腺组织(清甲)治疗临床转归的预测价值。方法采用回顾性研究方法,收集2015年1月至2017年6月收治的95例PTC患者的临床资料,手术后均行131 I清甲治疗。依据患者淋巴结转移率的不同,分为A组(转移率≤10%)14例、B组(转移率>10%且≤25%)36例、C组(转移率>25%且≤50%)33例、D组(转移率>50%)12例。随访9~27个月,中位随访20个月,统计患者治疗后临床转归情况(满意、不确切、反应欠佳)。比较各组患者临床资料和临床转归情况,绘制受试者工作特征(ROC)曲线评价淋巴结转移率对预测临床转归为满意的最佳诊断阈值和诊断效能,通过多因素Logistic回归分析预测患者临床转归情况的独立影响因素。结果各组患者性别、肿瘤T分期、肿瘤部位及肿瘤直径比较,差异均无统计学意义(P均>0.05);各组年龄、病灶数量和腺外侵犯情况比较,差异有统计学意义(P均<0.01)。各组治疗后临床转归情况比较,差异有统计学意义(P<0.01)。淋巴结转移率最佳诊断阈值为52.30%,此时预测患者临床转归为满意的敏感度为53.57%,特异度达94.87%,ROC曲线下面积为0.76。年龄、多发病灶、腺外侵犯及淋巴结转移率均是预测患者临床转归情况的独立影响因素(P<0.05,P<0.01)。结论淋巴结转移率与PTC患者手术后131 I清甲治疗的临床转归情况密切相关,随着淋巴结转移率的升高,患者临床转归情况往往较差;淋巴结转移率的最佳诊断界值为52.30%,可作为预测患者临床转归情况的独立特异性指标。     

SARS-CoV-2 Infection Hospitalization Rate and Infection Fatality Rate Among the Non-Congregate Population in Connecticut

BackgroundInfection fatality rate and infection hospitalization rate, defined as the proportion of deaths and hospitalizations, respectively, of the total infected individuals, can estimate the actual toll of coronavirus disease 2019 (COVID-19) on a community, as the denominator is ideally based on a representative sample of a population, which captures the full spectrum of illness, including asymptomatic and untested individuals.ObjectiveTo determine the COVID-19 infection hospitalization rate and infection fatality rate among the non-congregate population in Connecticut between March 1 and June 1, 2020.MethodsThe infection hospitalization rate and infection fatality rate were calculated for adults residing in non-congregate settings in Connecticut prior to June 2020. Individuals with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies were estimated using the seroprevalence estimates from the recently conducted Post-Infection Prevalence study. Information on total hospitalizations and deaths was obtained from the Connecticut Hospital Association and the Connecticut Department of Public Health, respectively.ResultsPrior to June 1, 2020, nearly 113,515 (90% confidence interval [CI] 56,758-170,273) individuals were estimated to have SARS-CoV-2 antibodies, and there were 7792 hospitalizations and 1079 deaths among the non-congregate population. The overall COVID-19 infection hospitalization rate and infection fatality rate were estimated to be 6.86% (90% CI, 4.58%-13.72%) and 0.95% (90% CI, 0.63%-1.90%), respectively, and there was variation in these rate estimates across subgroups; older people, men, non-Hispanic Black people, and those belonging to 2 of the counties had a higher burden of adverse outcomes, although the differences between most subgroups were not statistically significant.ConclusionsUsing representative seroprevalence estimates, the overall COVID-19 infection hospitalization rate and infection fatality rate were estimated to be 6.86% and 0.95%, respectively, among community residents in Connecticut.