Mouthguards: difference in longitudinal dimensional stability between single- and double-laminated fabrication techniques

Abstract –  Though the use of mouthguards (MGs) has increased with the increase in sporting activities, little is known about the influence of their fabrication methods on longitudinal dimensional stability. The objective of this study was to compare the difference in the longitudinal dimensional stability between single and laminated MGs. Single-layer MGs were made from a 4.0 mm thick ethylene vinyl acetate (EVA) sheet and laminated MGs were made from two 2.0 mm thick sheets of EVA. MGs were kept in a 37°C water bath for 60 h, equivalent to the time period of 3-months inter-oral use. MG deformation was analyzed by measuring designated points on the MG border using a profile projector (J-12, Nikon Inc., Tokyo, Japan) before and after the water immersion. A finite-element model was also created to examine the time course of stress accumulation during the sheet forming process using Finite Element software. Longitudinal deformation was smaller in the laminated MGs than in the single-layer MGs in the anterior area ( P  < 0.05). Finite element method (FEM) analysis also showed the largest stress accumulation in the anterior incisal area where deformations were mainly observed. Laminated double layer MGs have advantages over single-layer MGs in terms of longitudinal stability due to lower stress accumulation during the fabrication process.     

以改良TRAP法检测人膀胱肿瘤组织中端粒酶活性表达的临床意义

目的：探讨膀胱肿瘤及癌旁组织端粒酶活性表达及临床意义。方法：以改良TRAP法测定91例膀胱癌组织标本端粒酶活性表达。结果：83例膀胱移行细胞癌组织中78例检出端粒酶活性。阳性率为94％，其对应的癌旁组织也有14％的检出率，8例膀胱乳头状瘤组织中4例检出端粒酶活性，阳性率为50％，其对应的癌旁组织检出率为12％，端粒酶活性在不同临床病理类型的膀胱肿瘤及癌旁组织中表达无显差异（P＞0．05），结论：应用非放射性的银染方法对端粒酶的活性进行检测，图像清晰，简便，安全，易于临床推广。     

鹅去氧胆酸连接氨基酸的合成

胆石症是一种常见病,鹅去氧胆酸(CDCA)可用于胆固醇胆石症的治疗。它能改变胆汁组成,降低胆汁内胆固醇饱和度,增加胆固醇溶解性,使胆石逐渐溶解。但CDCA易被肠道内细菌7-脱羟酶作用生成石胆酸(LC),引起腹泄、腹部痉挛、高转     

医疗设备投资决策的敏感性分析研究

不恰当的医疗设备投资对医院及患者的利益均会造成损失，因此，在投资决策前进行严谨科学地可行性评估十分必要。通过对净现值的敏感性分析，医院的决策者可以了解各种不确定因素对投资方案经济效果的影响程度，以及投资方案对外部条件变化的承受能力，从而掌握风险条件下正确的决策原则和决策方法。     

Smoothing the mosaic subclinical melanoderma by calcipotriol

BACKGROUND: The observation of photo-exposed skin under ultraviolet light reveals a mosaic pattern of varying intensity in epidermal melanization. Several patterns of mosaic subclinical melanoderma (MSM) have been described using a specially designed CCD camera and the ultraviolet light-enhanced visualization (ULEV) method. Vitamin D(3) and its analogues influence the biology of keratinocytes and melanocytes. OBJECTIVE: To assess the effect of calcipotriol on MSM. METHODS: This randomized split-face study was conducted in 27 men to compare the effect of once daily applications of 5% calcipotriol cream or a moisturizing cream on the heterogeneity of facial MSM. Computerized image analysis of video images was used at 1-month intervals before and during a 2-month treatment, as well as during a 3-month follow-up. RESULTS: At both sites, the average melanin content of the epidermis showed no significant change over time. However, the mottled appearance was smoothened at the calcipotriol site, whereas it was increased at the site receiving the moisturizer. CONCLUSION: The decreased heterogeneity in MSM after calcipotriol applications suggests a control of the epidermal melanocyte unit by the vitamin D(3) derivative.     

原发性肝癌患者术前肝储备功能的预测和术后评价

目的 运用脉动色素浓度法(PDD)测定吲哚氰绿潴留率(ICGR15)及有效肝脏血流量(EHBF)评估原发性肝癌患者术前肝脏的储备功能.方法 对55例原发性肝癌患者术前应用PDD法检测ICGR15和EHBF并根据ICGR15分为3组,并行Child-Pugh评分;根据术后肝功的恢复情况将患者分为肝功能恢复良好(G)、轻度不全(M)和重度不全组(S).分析ICGR15三组中术后肝功不全的发生率以及在不同肝功恢复组中ICGR15、EHBF与Child-Pugh评分比较.结果 术后肝功不全在ICGR15三组中的发生率差异具有统计学意义(P＜0.05);肝功恢复不同组间ICGR15、EHBF同Child-Pugh评分比较具有显著性差异(P＞0.05);在不同的Child-Pugh分级之间,ICGR15及EHBF值差异有统计学意义(P＜0.05).结论 ICGR15、EHBF比传统Child-Pugh评分可以更准确的评估肝储备功能并指导确定手术方案.     

Detailed Analysis of Mucosal Restoration of the Small Intestine After the Cavitary Two-Layer Cold Storage Method

Small bowel transplantation (SBT) is associated with a high incidence of infectious complications because of ischemia/reperfusion (I/R) mucosal injury concomitant with potent immunosuppression. In this study, we evaluated whether the cavitary two-layer method (cTLM) could reduce I/R injury and allow early mucosal restoration, particularly after prolonged preservation and transplantation. Canine heterotopic segmental SBT was performed immediately without preservation (group 1), after 24-h preservation in UW solution (group 2) or by the cTLM (group 3). The graft samples were taken 1 h after reperfusion and on days 1, 4 and 7. We assessed graft mucosa with detailed microscopic and electromicroscopic analyses. In Group 3, histological injury and cell apoptosis after transplantation were significantly alleviated and rapidly recovered to a similar level of group 1. The mucosal restoration was morphologically completed within 4 days. In contrast, in group 2, more pronounced mucosal injury and delayed recovery were noted. Crypt cell proliferation activity was well maintained in groups 1 and 3 throughout the experimental period. Our ultrastructural analysis suggested that mitochondrial integrity achieved by the cTLM was a basal mechanism under the prompt mucosal restoration. The cTLM could reduce I/R injury, facilitate mucosal regeneration and restore the nearly normal structure early after SBT.     

用Alabama分析法比较安氏Ⅰ类错中国人与美国白人颅颌面结构差异

目的:研究中国安氏Ⅰ类错成人与美国安氏Ⅰ类错白人牙颌颅面形态结构的差异。方法:从西安市11所大学2098名新生中选取符合标准的101名(男53名、女48名)安氏Ⅰ类错样本。拍摄头颅定位X线片,用第四军医大学口腔医学院头影测量软件测量,用Alabama分析法与美国安氏Ⅰ类错白人颅颌面测量结果进行比较分析。结果:中国西安地区安氏Ⅰ类错成人上下颌突度大,面型较突;平面倾斜度、上下中切牙倾斜度及下中切牙至NB线距均较大;Y轴相对SN平面夹角增大,生长方向为后下。结论:与美国安氏Ⅰ类错白人比较,中国西安地区安氏Ⅰ类错成人颅面结构呈现颌骨突度大、下切牙唇倾及下颌趋向后下等特征。     

Significance of beaten copper appearance on skull radiographs in children with isolated sagittal synostosis

Aims and Objectives The significance of beaten copper appearance (BCA) on skull radiographs in children following surgery for isolated sagittal craniosynostosis has not been studied. This study was designed to look for any correlation between BCA and symptoms suggestive of intracranial hypertension in this group of patients. Materials and Methods Forty-eight consecutive children, who were operated for isolated sagittal synostosis from1987 to 2000 and had postoperative skull radiographs, were included. Patients were divided into: (a) BCA group (n = 20), consisting of children who had beaten copper appearance on skull radiographs at last follow up, and (b) Non-BCA group (n = 28), consisting of children who did not have this finding. Records were reviewed to look for symptoms suggestive of intracranial hypertension, such as headache, head banging, and irritability. Results Median age at surgery was 4.8 months for BCA group and 4 months for the non-BCA group. Follow up ranged from 4 to 156 months with a mean of 36.2 months. Total of 28.6% (n = 6) of the children with follow up radiographs done at ≤18 months of age had BCA. The incidence of BCA increased to 83.3% in children with skull radiographs performed after 48 months of age. In 18 (90%) children, the BCA was ‘diffuse’ with 5 (25%) children having the maximum possible score of 8. In the BCA group, 45% (n = 9) had symptoms compared to 10.7% (n = 3) in the control group (p = 0.0068). Conclusions This study suggests a significant number of children with BCA on radiographs develop symptoms suggestive of raised ICP following surgical treatment in infancy and prolonged follow up may be warranted in this group of patients.     

额、枕部直接冲击导致中脑损伤的力学机制研究

目的分析额、枕部直接冲击造成中脑应力响应,探讨颅脑直接冲击导致脑干损伤的力学机制。方法构建头颅三维有限元模型,模拟计算额、枕部直接冲击损伤,分析中脑上、下交界面节点应力分布,总结中脑应力响应。结果中脑-间脑界面在冲击初始阶段,2ms即出现应力增高,中脑-桥脑界面应力升高开始于冲击后期(10ms),两交界面节点应力在冲击时程中均持续升高,额部冲击比枕部冲击在中-间脑界面造成的应力峰值高。结论中脑在颅脑直接冲击伤的致伤机制中占有突出地位,中脑的应力改变可解释脑震荡的意识障碍及部分原发脑干伤的临床表现。