Utility of auditory steady-state and brainstem responses in age-related hearing loss in rats

Conclusions: The results support the idea that auditory steady-state response (ASSR) is a more accurate test for studying age-related hearing loss (ARHL) in Sprague-Dawley rats. Differences in the rat middle ear may explain the variations of the click properties, with a displacement of the energy toward the 8 and 10 kHz frequencies compared with humans. Objectives: The purpose of this study was to evaluate ARHL in older and younger Sprague-Dawley rats using auditory clicks and tone burst with auditory brainstem response (ABR), in addition to ASSR. Methods: This was a prospective cohort study with 50 animals divided into 5 groups based on their age in months. A total of 100 registers were elicited from each one of the 3 auditory measurements systems in an electrically shielded, double-walled, sound-treated cabin. Nine frequencies, from 0.5 to 16 kHz were analyzed with the auditory steady-state response and compared with the results elicited by the clicks and tone-burst ABR. Results: Comparisons between the different frequencies showed lower thresholds in those frequencies below 2 kHz, independently of their age in months. The ARHL was detected by each one of the three auditory measurement systems, but with lower thresholds with the ASSR test. Finally, auditory clicks showed better correlations with 8 and 10 kHz elicited by ASSR, which was different to what was expected, based on human studies.     

A clinical study of sudden deafness

Conclusions: Sudden Sensorineural Hearing Loss (SSHL) was commonly seen in middle aged people. Tinnitus was reported by 87.2% of the patients, and dizziness or vertigo were reported by 48.5%. The most common concomitant disorder of SSHL was hyperlipidemia. Objective: A retrospective register study with SSHL was performed in Xi’an, China, from 2000–2009. Results: Of 617 inpatients, the right ear was affected in 267 cases, the left ears in 282 cases, and both ears in 68 cases. The most common age of patients was 41–50 years. There were 20.4% SSHL patients with hypertension, coronary artery disease, or diabetes, and 49.6% patients with hyperlipidemia. Auditory Brainstem Responses (ABR) were performed in 460 patients (504 ears) before treatment, and the ABR threshold of 56.4% ears was > 90 dB. The constituent ratio of patients with an ABR threshold over 90 dB was greater in the vertigo group than the other group. CT and/or MRI scans were available in 277 cases, of which 40 cases (14.4%) were abnormal.     

Oral pretreatment with recombinant human lactoferrin limits trauma-hemorrhagic shock–induced gut injury and the biological activity of mesenteric lymph

Background

Lactoferrin (LF) is a pleiotropic glycoprotein that is found in bodily secretions and is postulated to enhance the gastrointestinal barrier and promote mucosal immunity. Thus, the ability of talactoferrin, an oral recombinant form of human LF, to limit gut injury and the production of biologically active gut-derived products was tested using a rat model of trauma–hemorrhagic shock (T/HS).

Methods

Male rats were orally dosed with vehicle or talactoferrin (1000 mg/kg, every day) for 5 d before being subjected to T/HS or trauma–sham shock (T/SS). Subsequently, rats were subjected to a laparotomy (trauma) and hemorrhagic shock (mean arterial pressure, 30–35 mm Hg × 90 min) or to T/SS, followed by resuscitation with their shed blood. Before inducing shock, the mesenteric lymphatic duct was catheterized for collection of mesenteric lymph. Four hours after the end of the shock or sham-shock period, rats were sacrificed, a segment of the distal ileum was collected for morphologic analysis, and lymph samples were processed and frozen. Subsequently, lymph samples were tested in several pharmacodynamic assays, including endothelial cell permeability, neutrophil respiratory burst activity, and red blood cell (RBC) deformability. Total white blood cell counts in lymph samples were also quantified.

Results

Pretreatment with talactoferrin reduced the incidence of T/HS-induced morphologic injury of ileum to T/SS levels. Post-T/HS lymph from vehicle-treated rats increased endothelial monolayer permeability and neutrophil priming for an augmented respiratory burst, and induced loss of RBC deformability, compared with T/SS groups. Talactoferrin pretreatment significantly reduced the biological activity of T/HS lymph on respiratory burst activity and RBC deformability, but had no effect on the lymph cell count or endothelial cell permeability.

Conclusions

These results provide a proof of principle that prophylactic dosing of oral talactoferrin can potentially protect the gut in a T/HS model and limit the production of biologically active factors in rat gastrointestinal tissue subjected to ischemia-reperfusion–type injuries.     

醋酸亮丙瑞林原位注射制剂的制备及其体内外释放性能的研究

目的：合成mPEG/PLA比例为10/90,5/95,2/98的3种聚合物并对其进行结构表征。用合成的mPEG-PLA为载体材料和有机溶剂N-甲基比咯烷酮（NMP）制备醋酸亮丙瑞林（LA）的原位注射剂并对其物理化学性质和体内外释放试验进行研究。方法：采用mPEG2000和外消旋-丙交酯（DL-LA）,以开环聚合法合成比例为10/90,5/95,2/98的聚合物mPEG-PLA,并通过1H-NMR对产物进行结构确证。然后将mPEG-PLA和LA置于两个注射器中,制成A/B系统,在使用前将药物加入聚合物溶液中并混合均匀,制备醋酸亮丙瑞林的原位注射剂。利用显微镜和SEM分析制剂结构。其次进行药物的体外释放试验,对释放曲线进行模型拟合,最后以大鼠为动物模型进行试验,考察药物在SD大鼠体内的释放行为,并考察体内外相关性。结果：成功合成且验证了不同比例的mPEG/PLA聚合物,并以此为载体材料成功制备出LA原位注射制剂。体外释放试验表明,药物以接近零级的方式释放,释放速率和聚合物mPEG/PLA比例,载药量和加入有机溶剂的量有关,且聚合物中PLA比例越高释放越慢,载药量增加则释放速率增加;选用黏度大的溶剂则药物释放减慢,溶剂的用量增加释放速率减小;大鼠体内实验也表明该制剂在体内能够达到缓释的效果,药物在前10 d内释放较快,30 d释放药物能达到90%。结论：醋酸亮丙瑞林原位注射制剂物理化学性质稳定,体内外实验均证明该制剂具有良好的释放性能。     

Acute sleep deprivation in healthy young men: Impact on population diversity and function of circulating neutrophils

Lack of sleep greatly affects our immune system. The present study investigates the acute effects of total sleep deprivation on blood neutrophils, the most abundant immune cell in our circulation and the first cell type recruited to sites of infection. Thus, the population diversity and function of circulating neutrophils were compared in healthy young men following one night of total sleep deprivation (TSD) or after 8 h regular sleep. We found that neutrophil counts were elevated after nocturnal wakefulness (2.0 ± 0.2 × 10⁹/l vs. 2.6 ± 0.2 × 10⁹/l, sleep vs. TSD, respectively) and the population contained more immature CD16^dim/CD62L^bright cells (0.11 ± 0.040 × 10⁹/l [5.5 ± 1.1%] vs. 0.26 ± 0.020 × 10⁹/l [9.9 ± 1.4%]). As the rise in numbers of circulating mature CD16^bright/CD62L^bright neutrophils was less pronounced, the fraction of this subpopulation showed a significant decrease (1.8 ± 0.15 × 10⁹/l [88 ± 1.8%] vs. 2.1 ± 0.12 × 10⁹/l [82 ± 2.8%]). The surface expression of receptors regulating mobilization of neutrophils from bone marrow was decreased (CXCR4 and CD49d on immature neutrophils; CXCR2 on mature neutrophils). The receptor CXCR2 is also involved in the production of reactive oxygen species (ROS), and in line with this, total neutrophils produced less ROS. In addition, following sleep loss, circulating neutrophils exhibited enhanced surface levels of CD11b, which indicates enhanced granular fusion and concomitant protein translocation to the membrane. Our findings demonstrate that sleep loss exerts significant effects on population diversity and function of circulating neutrophils in healthy men. To which extent these changes could explain as to why people with poor sleep patterns are more susceptible to infections warrants further investigation.     

A prospective study of BurstDR™ spinal cord stimulation for non-operated discogenic low back pain

Introduction

Chronic discogenic low back pain (CD-LBP) is caused by degeneration of the disc due to trauma to the annulus or by unprovoked degeneration, resulting in chronic pain. Spinal cord stimulation (SCS) employing the BurstDR™ waveform has been shown to be an effective treatment in a variety of chronic pain conditions. The aim of this prospective case study was to determine the effect of BurstDR™ SCS on pain relief, disability, and patient satisfaction in a population with CD-LBP.

Methods

Seventeen subjects with CD-LBP received a SCS trial with BurstDR™ stimulation. Patients with >50% pain relief after a trial period of 2 weeks were permanently implanted (n = 15). Patients then rated LBP and leg pain using the numeric rating scale (NRS), Oswestry disability index (ODI), patient global impression of change (PGIC), EQ-5D quality of life, and painDETECT for neuropathic pain at baseline following trial, 3, 6, and 12 months after permanent implantation.

Results

Treatment with BurstDR™ SCS resulted in significant reduction of LBP as the NRS was reduced from 71.7 ± 7.3 at baseline to 42.5 ± 18.1 at 12 months. Average pain relief at 12 months was 42.5%. In patients with leg pain (n = 8), pain was significantly reduced from 66.9 ± 8.2 to 11.7 ± 10.4 at 12 months. PainDETECT scores for neuropathic pain significantly reduced from 18.9 ± 4.8 at baseline, and 14.8 ± 3.2 at 12 months. Baseline ODI score significantly reduced from 41.2 ± 12.8 to 25.8 ± 8.6 at 12 months. PGIC scores remained low from 2.6 ± 1.6 at 3 months, 2.5 ± 1.0 at 6 months, and 2.5 ± 1.3 at 12 months. EQ-5D-5L rates remained constant from baseline 56.10 ± 23.9 to 68.6 ± 12.9 at 12 months.

Conclusion

BurstDR™ SCS resulted in significant reduction of back pain, leg pain, and quality of life in patients with CD-LBP and decreased the level of disability and generated positive patient satisfaction scores.     

Left posterior parietal theta burst stimulation affects gestural imitation regardless of semantic content

ObjectiveNeuro-imaging studies have suggested that the ability to imitate meaningless and meaningful gestures may differentially depend on superior (SPL) and inferior (IPL) parietal lobule. Therefore, we hypothesized that imaging-guided neuro-navigated continuous theta burst stimulation (cTBS) over left SPL mainly affects meaningless and over left IPL predominantly meaningful gestures.MethodsTwelve healthy subjects participated in this study. High resolution structural MRI was used for imaging guided neuro-navigation cTBS. Participants were targeted with one train of cTBS in three experimental sessions: sham stimulation over vertex and real cTBS over left SPL and IPL, respectively. An imitation task, including 24 meaningless and 24 meaningful gestures, was performed ‘offline’.ResultscTBS over both left IPL and SPL significantly interfered with gestural imitation. There was no differential effect of SPL and IPL cTBS on gesture type (meaningless versus meaningful).ConclusionsOur findings confirm that left posterior parietal cortex plays a predominant role in gestural imitation. However, the hypothesis based on the dual route model suggesting a differential role of SPL and IPL in the processing of meaningless and meaningful gestures could not be confirmed.SignificanceLeft SPL and IPL play a common role within the posterior–parietal network in gestural imitation regardless of semantic content.     

后路钉棒反弓折顶技术结合椎弓根植骨治疗胸腰段椎体爆裂骨折

文题释义： 反弓折顶技术：目前临床上单纯后路手术治疗胸腰段爆裂骨折的效果不甚满意。传统单纯撑开通过前纵韧带复位技术,不能很好地恢复椎体高度。反弓折顶技术通过改型棒作用使前柱充分撑开,恢复椎体前柱高度,再撑开后方为椎弓根植骨提供可靠空间。 椎弓根植骨：通过伤椎椎弓根通道将自体骨颗粒或者异体骨植入伤椎骨折处,填充椎体压缩缺损,避免骨折愈合后“空壳现象”形成,在通过椎体置钉于植骨区下方,对植骨区支撑作用,有效维持骨折愈合后高度,降低断钉断棒等并发症。 背景：胸腰段爆裂骨折发病率较高,后路单纯撑开技术在维持椎体高度、降低并发症方面的疗效不甚满意,因此试图探索更佳治疗方案。 目的：探讨采用反弓折顶技术结合椎弓根植骨治疗胸腰段椎体爆裂骨折的效果。 方法：前瞻性纳入78例胸腰段椎体爆裂骨折患者,均为闭合性新鲜骨折,均采用后路手术,伤后至手术时间4-14 d,平均7.8 d。随机分为2组,单纯撑开组38例行单纯椎弓根钉棒系统撑开复位固定,反弓折顶植骨组40例行后路钉棒反弓折顶技术结合椎弓根植骨固定。2组患者对治疗方案均知情同意,且得到医院伦理委员会批准。对比2组手术时间及术中出血量、骨折愈合时间、术后伤椎前缘高度比值、Cobb角、目测类比评分、生活活动能力(Barthel指数)及术后并发症发生情况。 结果与结论：①所有患者获得10-22个月随访;②单纯撑开组手术时间及术中出血量均优于反弓折顶植骨组(P < 0.01);③2组术后伤椎前缘高度比值、Cobb角差异有显著性意义(P < 0.01),反弓折顶植骨组优于单纯撑开组;④2组骨折愈合时间、术后生活活动能力(Barthel指数)差异均有显著性意义(P < 0.01),反弓折顶植骨组优于单纯撑开组;⑤术后2组均未发生深部感染,反弓折顶植骨组未发生内固定失败、椎体高度过度丢失等并发症;单纯撑开组发生内固定失败螺钉拔出3例,钛棒断裂2例,椎体高度明显丢失10例;⑥提示与单纯撑开复位固定相比,后路钉棒反弓折顶植骨并伤椎置钉固定可形成伤椎压缩中心骨性支撑,重建前、中柱高度方面疗效确切,具有力学强度高、椎体高度维持好、骨愈合率高、并发症少的优点,将是治疗胸腰椎爆裂骨折较为理想的选择。 ORCID: 0000-0001-8648-1076(朱福良) 中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程     

Auditory neural myelination is associated with early childhood language development in premature infants

Background

Auditory neural myelination (ANM) as evaluated by auditory brainstem evoked response (ABR) during the neonatal period has been used as a surrogate outcome for long-term neurodevelopment. The validity of ANM as a surrogate outcome for long-term neurodevelopment has not been well studied.

Aim

Evaluate the association of ABR I–V interpeak latency (IPL), an index of ANM, at 35 week postmenstrual age (PMA) with language outcome at 3 years of age.

Design

Prospective study.

Subjects

24–33 week gestational age (GA) infants were eligible if they did not meet exclusion criteria: craniofacial malformation, chromosomal disorders, deafness, auditory dys-synchrony, TORCH infection, or non-English speaking parents. Infants with malignancy, head injury, encephalopathy, meningitis, blindness, or who died or relocated were also excluded.

Outcome measures

ABRs were performed at 35 week PMA using 80 dB nHL and I–V IPL (ms) measured. Auditory Comprehension (AC) and Expressive Communication (EC) were evaluated by a speech-language pathologist at 3 years of age using Preschool Language Scale.

Results

Eighty infants were studied. The mean GA and birth weight of infants were 29.2 weeks and 1336 g, respectively. There was association of worse ear I–V IPL and better ear I–V IPL with AC (Coefficient − 5.4, 95% CI: − 9.8 to − 0.9 and Coefficient − 5.5, 95% CI: − 10  to−0.9, respectively) and EC (Coefficient − 5.6, 95% CI: − 9.5  to−1.8 and Coefficient − 6.7, 95% CI: − 10.6  to−2.7, respectively) after controlling for confounders.

Conclusion

The neonatal I–V IPL is a predictor of language development at 3 years of age in preterms.