Spatial distribution of evoked potentials in the inferior olivary nucleus by stimulation of the visual afferents in the rat

Visual pathways (optic disc, optic nerve and pretectal regions) were electrically stimulated and evoked potentials were explored throughout the inferior olive in the anesthetized rat. Responsive areas were identified as the caudal half of the dorsal cap, nucleus beta and the most caudal region of subnucleus c of the medial accessory olive. No field potentials were identified in the rostral half of the dorsal cap, its ventrolateral outgrowth or the dorsomedial cell column. Contralateral retinal afferents were only effective all over the responsive areas.     

Association between abdominal fat distribution and coronary plaque instability in patients with acute coronary syndrome

Background and aimsThis study aimed to assess possible association of detailed abdominal fat profiles with coronary plaque characteristics in patients with acute coronary syndrome (ACS).Methods and resultsIn 60 patients with ACS, culprit arteries were evaluated at 1-mm intervals (length analyzed: 66 ± 28 mm) by grayscale and integrated backscatter intravascular ultrasound (IB-IVUS) before percutaneous coronary intervention. Standard IVUS indexes (as a volume index: volume/length), plaque components (as percent tissue volume) and fibrous cap thickness (FCT) were assessed by IB-IVUS. Plain abdominal computed tomography was performed to evaluate subcutaneous adipose tissue (SAT) area, visceral adipose tissue (VAT) area, and VAT/SAT ratio. While SAT area only correlated with vessel volume (r = 0.27, p = 0.04), VAT area correlated positively with vessel (r = 0.30, p = 0.02) and plaque (r = 0.33, p = 0.01) volumes and negatively with FCT (r = −0.26, p = 0.049), but not with percent plaque volume and plaque tissue components. In contrast, higher VAT/SAT ratio significantly correlated with higher percent lipid (r = 0.34, p = 0.008) and lower percent fibrous (r = −0.34, p = 0.007) volumes with a trend toward larger percent plaque volume (r = 0.19, p = 0.15), as well as thinner FCT (r = −0.53, p < 0.0001). In the multiple regression analysis, higher VAT/SAT ratio was independently associated with higher percent lipid with lower percent fibrous volumes (p = 0.03 for both) and thinner fibrous cap thickness (p = 0.0001).ConclusionCoronary plaque vulnerability, defined as increased lipid content with thinner fibrous cap thickness, appears to be more related to abnormal abdominal fat distribution, or so-called hidden obesity, compared with visceral or subcutaneous fat amount alone in patients with ACS.     

Acid diffusion through rat duodenal mucosal cap

Acid induced duodenal injury occurs immediately following exposure to strong acid but does not worsen despite continuous perfusion with the acid. A thick gelatinous cap is found overlying the duodenum when examined histologically. The purpose of this study was to quantitate the resistance to acid diffusion by native duodenal mucus and the cap material. Rat duodenum was perfused with acid. The mucus from control and acid-perfused animals was harvested and the diffusion coefficient measured. Mucus from the duodenums of anesthetized rats was mixed with bromphenol blue and placed into capillary tubes. The tubes were submersed in 0.15 N HCl at 37°C. The color change from blue to yellow was measured with time as the HCl migrated through the tube. From the distance and time data, the diffusion coefficient could be calculated. Controls of bromphenol blue in water were studied. The diffusion coefficient for HCl in water was 30.1 ± 0.9 × 10^–6 cm²/sec, nearly identical to the standard value reported in the literature. For the duodenal mucus adherent to the epithelial surface, it was 1.1 ± 0.1 × 10^–6 cm²/sec. Following perfusion with 0.15 N HCl, a 279.6 ± 44-m-thick mucus cap formed over the duodenum that had a diffusion coefficient of 1.8 ± .3 × 10^–8 cm²/sec. In response to injury, the duodenum protects against continued damage by producing a mucoid cap that it highly resistant to acid diffusion.     

基牙不同牙周状况下球帽附着体义齿支持组织的应力分析

目的探讨基牙牙周组织不同程度吸收对球帽附着体义齿支持组织VonMises等效应力的影响。方法分别建立基牙牙周组织正常、吸收1／4、吸收1／3、吸收1／2的球帽附着体义齿模型,采用垂直向加载力300N,分析支持组织的VonMises等效应力变化。结果随着基牙牙周组织的吸收基牙应力集中区逐渐扩大,以根尖区扩大较明显,第二前磨牙颈部出现高应力区,最大VonMises等效应力分别为25．6962MPa、27．2047MPa、34．4062MPa、47．3841MPa;牙周膜根尖应力集中区也逐渐扩大;而缺牙区牙槽嵴的应力变化较小。结论基牙牙周组织吸收小于1／3时,支持组织应力逐渐增加,采取相应的措施减小验力,仍可使用球帽附着体义齿修复。吸收1／2时支持组织高应力区应力变化显著,对于此情况不建议采用球帽附着体义齿修复。     

SMILE术后角膜帽的观察研究——基于傅里叶频域光学相干断层扫描(FD-OCT)

目的通过傅里叶频域光学相干断层扫描(FD-OCT)对VisuMax飞秒激光制作角膜帽的早期临床观察,评价帽厚度的精确性、重复性、均一性及规整性,并研究SMILE术后不同方向不同时间帽厚度变化及其角膜上皮等可能的影响因素。方法回顾性研究。选取44例(87眼)拟行SMILE术的近视患者,采用FD-OCT测量术后1周、1个月角膜6 mm直径范围内水平和垂直子午线方向的角膜帽厚度。应用RVe软件工具在每个截面图上特定的7个点标定角膜帽的厚度。采用配对样本t检验分析术后帽厚度预期值与实际值差异及术后不同时间帽厚度差异,术后角膜帽厚度与术前参数等相关性采用Pearson线性相关分析。结果精确性:术后实际角膜帽厚度均较理论值厚,差异均有统计学意义(均为P<0.05);重复性:术后1周、1个月水平方向帽厚度标准差分别为2.64μm、3.41μm,术后1周、1个月垂直方向帽厚度标准差分别为3.36μm、3.10μm;均一性:术后1周水平方向各位点的帽厚度差异有统计学意义(t=3.246,P=0.004)、术后1个月水平方向各位点的帽厚度差异也有统计学意义(t=2.295,P=0.034);术后1周...     

透明帽辅助内镜下食管异物治疗术的疗效分析

目的比较透明帽辅助内镜下食管异物取出术及传统内镜下异物取出术的疗效差异。方法选取96例食管异物嵌顿患者随机分成两组,分别施行透明帽辅助内镜下异物取出术(简称透明帽组)或传统内镜下异物取出术(简称传统组),收集两组患者各项临床资料,同时记录其接受内镜下治疗的成功情况、内镜下操作时间、内镜下视野清晰度以及并发症发生情况等数据并进行统计分析。结果接受透明帽辅助内镜下异物取出术的48例患者,均成功完成异物取出治疗,另外48例接受传统内镜下异物取出患者中有46例成功,另外2例转为透明帽辅助下异物取出后成功(成功率95.83%),两组的成功率比较差异无统计学意义(P0.05);透明帽组的平均内镜下操作时间为(8.29±2.83)min,传统组的平均内镜下操作时间为(10.69±3.19)min,两组比较差异无统计学意义(P0.05);内镜下视野清晰度方面,透明帽组视野清晰度A级45例,B级3例,传统组视野清晰度A级35例,B级11例,C级2例,两组间比较差异有统计学意义(P=0.020);所有96例患者均未出现严重出血、穿孔及死亡等并发症。结论透明帽辅助内镜下食管异物取出术是一种安全有效的内镜下异物治疗方案,其可提供更好的内镜下操作视野,有利于提高手术成功率,值得进一步推广应用。     

Small neurons in the vestibular nerve root project to the marginal shell of the anteroventral cochlear nucleus in the cat

We injected biotinylated dextran amine (BDA) into marginal shell regions of the anteroventral cochlear nucleus (AVCN) of the cat. These injections led to retrograde labeling of cells including small cells (median soma area = 111 μm², equivalent diameter = 11.9 μm) in the vestibular nerve root (VNR), just ventral to an anterior part of the AVCN. This is an unexpected new finding. The cells were scattered among BDA-labeled fibers and were oriented parallel to the course of the VNR fibers. We suggest that the small neurons of the VNR might serve as second-order vestibular neurons conveying information from vestibular end organs to the cochlear nucleus (CN) and/or act as interneurons between the olivocochlear fibers in the VNR and the CN.     

Factors affecting treatment outcomes following complicated crown fractures managed in primary and secondary care

Abstract – The aims of this retrospective observational study were to determine the factors which affect treatment provision and the Median Survival Time (MST) for maintenance of tooth vitality following complicated crown fracture. The survey was carried out for patients treated at Newcastle Dental Hospital (NDH) according to departmental guidelines over a 2‐year period following the introduction of a new protocol for management of these types of injuries. Seventy‐three cases of complicated crown fracture were identified in 69 children with a mean age of 10.3 years (SD = 2.5 years). Seventy‐one percent of the fractures occurred in males (M:F ratio was 2.5:1). Fifty‐one percent of the complicated crown fractures were in immature teeth. Of the 73 traumatised teeth, 45% presented initially in general dental practice (GDP), 37% at the dental hospital and 8% at local accident and emergency departments with the remaining 10% seen at other or unrecorded locations. Of the 41 fractures, which presented initially at a location other than the dental hospital, 38% were referred to the dental hospital without the provision of an emergency pulp bandage. The overall definitive treatments provided for the 37 open apex teeth included pulp cap (19%), partial pulpotomy (32%), cervical pulpotomy (8%) and pulpectomy (35%), while for the 36 closed apex teeth it was pulp cap (28%), pulpotomy (11%), and pulpectomy (61%). Of the 30 teeth, which underwent vital pulp therapy (18 open and 12 closed apex), the MST for the 15 teeth treated with pulp caps was 1460 days (95% CI: 1067, 1853) while for the 15 teeth treated with pulpotomies it was 1375 days (95% CI: 964, 1786). There was no statistically significant difference in the MST between teeth treated with pulp caps and pulpotomies. In conclusion, the proportion of patients referred to secondary care with complicated crown fractures without provision of a pulp bandage is of some concern. More conservative treatment of closed apex teeth sustaining complicated crown fractures, utilizing vital pulp therapy techniques would appear to be appropriate.