多模态MRI技术和数值模拟技术用于脑血流灌注研究进展

脑血管疾病发病机制复杂,包括脑实质损伤、脑血流和脑脊液循环异常等。MRI脑血流灌注成像可评估脑结构和功能,结合数值模拟技术及流体间的差异,更准确地描述脑的病理变化。本文就多模态MRI技术结合数值模拟对脑血管疾病的脑血流灌注研究进展进行综述。     

Mannose-binding lectin gene polymorphisms are not associated with susceptibility to severe early childhood caries

Our purpose was to investigate a possible relationship between severe early childhood caries (S-ECC) and polymorphism of the mannose binding lectin gene and investigate the role of allele variant as a possible factor in the susceptibility to S-ECC. Sixty-two Chinese children with S-ECC and 68 caries-free control children were included in this study. Genomic DNA was extracted from buccal epithelial cells of each individual. The identification of MBL B allele was performed by restriction fragment length polymorphism using Ban I restriction enzyme. The frequency of MBL mutant genotype (GGC/GAC and GAC/GAC) was more frequent among children with S-ECC compared with control groups, but did not significantly differ between two groups (x² = 2.82, p > 0.05). There was no significant difference in the allele frequency of codon54 wild type (allele A) between two groups (x² = 2.76, p > 0.05). The present study did not find evidence of MBL codon54 polymorphisms being associated with S-ECC in the population studied, but a larger sample size is necessary to confirm the present results.     

Reliability of a computer-based neurobehavioral assessment test battery for Bangladeshi adolescent children

In developing countries, there is a need for low-cost neurobehavioral (NB) test batteries for vulnerable populations, particularly for children exposed to environmental neurotoxicants. The objective of the current study was to assess the feasibility and test-retest reliability of the Behavioral Assessment and Research System (BARS) in children from a rural community in Bangladesh. Fifty healthy adolescents living in the Health Effects of Arsenic Longitudinal Study (HEALS) area in Araihazar, Bangladesh completed all six tests from the BARS in two test sessions scheduled two weeks apart. The BARS tests evaluated NB functions such as motor coordination, attention, memory, and information processing speed. The reliability assessment, evaluated by test-retest correlations demonstrated moderate to strong correlations (i.e., correlation coefficients ranged from 0.43 to 0.85), which were statistically significant (p < 0.05). Paired t-tests for comparing the test and retest outcomes indicated significant improvement in NB performance, highlighting learning and practice effects. NB performance improved with increasing age in most cases. Adolescent boys performed better than the girls in Finger Tapping, Digit Span, and Simple Reaction Time, whereas the girls performed better in Continuous Performance and Symbol Digit tests. The reliability scores (Pearson’s correlations 0.43−0.85) were consistent with other children studies in different cultural settings. The effects of age and sex on NB tests were also consistent with findings reported in other countries. Overall, the findings of the study support the feasibility of using this computer-based test system to assess vulnerability of brain health due to environmental exposures among rural Bangladeshi children.     

Sequence analysis of the whole genome of a recombinant Marek’s disease virus strain, GX0101, with a reticuloendotheliosis virus LTR insert

Marek’s disease virus Chinese strain GX0101, isolated in 2001, is the first reported recombinant gallid herpesvirus type 2 (GaHV-2) field strain with one reticuloendotheliosis virus (REV) long terminal repeat (LTR) insert. We constructed an infectious bacterial artificial chromosome (BAC) clone of GX0101, which showed characteristics very similar to those of the parental virus in replication and pathogenicity. Using the GX0101 BAC clone, the complete genome of GX0101 was sequenced and analyzed. The length of the GX0101 genome is 178,101 bp, and it contains only one REV-LTR insert at a site 267 bp upstream of the sorf2 gene.     

髋关节假体体外磨损试验的应用及研究进展

体外磨损试验(ISO 14242)基于良好的实验室控制条件和操作规范模拟人体行走步态的关节承受载荷和运动角度范围,广泛用于比较髋关节假体不同材料、假体设计的耐磨损性能。本文基于体外磨损试验和临床磨损评价的研究文献,介绍体外磨损标准试验方法及其在髋关节设计开发中的应用,探讨体外磨损标准方法的局限、研究进展以及未来发展方向。     

一步一步做好全瓷修复粘接

随着全瓷材料和微创修复理念的发展,全瓷修复体的临床应用日益广泛。粘接是影响全瓷修复成功的重要因素之一。良好的粘接不仅能为全瓷修复体提供固位和抗力,还能增强修复体边缘封闭、提高修复体美观效果。做好全瓷修复粘接需要3个重要环节:全瓷修复体组织面的粘接处理、预备体表面牙体硬组织的粘接处理以及根据修复体类型正确选择粘接用水门汀。     

两种生物陶瓷材料用于乳磨牙牙髓切断术的随机对照研究

目的通过比较新型生物陶瓷材料iRoot BP Plus和三氧化矿物凝聚体(mineral trioxide aggregate,MTA)作为盖髓剂在乳磨牙牙髓切断术应用中的成功率,探讨iRoot BP Plus的临床应用价值。方法按照纳入和排除标准收集2018年8至12月于北京大学口腔医学院·口腔医院儿童口腔科行全身麻醉下治疗,口内至少有1对及以上同名乳磨牙龋坏须行牙髓切断术的3至8岁患儿,采用简单随机分组方法分别使用iRoot BP Plus(试验组)和MTA(对照组)行牙髓切断术,术后3、6及12个月随访,拍摄患牙根尖X线片,收集患牙治疗前后自觉症状、临床检查及影像学表现,计算两组的治疗成功率,并分析影响成功率的因素。结果研究共纳入患儿20例,男女各10例,共计28对、56颗乳磨牙(试验组28颗,对照组28颗),其中随访满1年者共23对、46颗乳磨牙。试验组3、6、12个月的治疗成功率分别为96%(25/26)、92%(22/24)和87%(20/23),对照组分别为100%(26/26)、96%(23/24)和96%(22/23),两组术后3、6、12个月的成功率差异均无统计学意义(P>0.05)。切髓后止血时间显著影响试验组的成功率(P<0.05)。结论iRoot BP Plus与MTA用于乳磨牙牙髓切断术1年随访期内均取得了较好的治疗效果,iRoot BP Plus在乳牙牙髓切断术中具有良好的临床应用前景。     

新广谱大肠杆菌噬菌体IME11的分离及鉴定

目的 分离广谱大肠杆菌噬菌体并对其进行种属的鉴定。方法 以不同种临床致病性大肠杆菌为指示菌,从未经处理的污水样品中分离噬菌体;采用蛋白酶K/SDS的方法提取噬菌体基因组,制备重组载体,将阳性重组质粒进行测序;将测序结果进行BLAST,推测该噬菌体种属分类位置。结果 分别以大肠杆菌E1 ～ E17共17种细菌作为指示菌,成功分离出一种广谱噬菌体,可裂解31株临床分离致病性大肠杆菌中的13株,并将其命名为IME11;由噬菌体基因组限制性酶切片段分析表明其遗传物质为dsDNA;将噬菌体IME11基因组的2个随机片段测序结果进行BLAST,推测其属于N4-like噬菌体属。结论 分离出了一种广谱噬菌体,在分类学上属于N4-like噬菌体属。     

探讨案例教学法在口腔美学修复实习教学中的应用

目的:探讨案例教学法应用在口腔美学修复临床实习教学中的效果。方法:选取39名在北京大学口腔医学院进行一阶段口腔修复临床实习的本科生,按实习编号分为两组;实验组(19名)采用案例教学法,选择以口腔美学修复为主的病例进行学习;对照组(20名)采用传统实习方法,并对两组学生进行临床考核和问卷调查。结果:实验组学生临床考核总分为41.87±3.92,显著高于对照组(38.30±4.62分)(,t=2.596,P=0.013);问卷调查显示,实验组满意度评分显著高于对照组(P<0.05),但学习负担两组无明显差异。结论:案例教学法应用于本科生口腔美学修复实习中,能够有效地训练学生口腔美学修复的临床思维,提高临床综合能力,辅助临床实习教学。     

MRI of the upper airway in non-snoring males

Objective

The aims of the study were to clarify the characteristics of the upper airway in children and to assess the effects of age on the upper airway.

Materials and methods

The study was part of a long-term observational research project on non-snoring males. The cohort of children comprised 28 volunteers with an age range of 8–12 years. The children group was compared to three different groups of adults: a youth group (n?=?30, age range 22–29 years), a middle-aged group (n?=?53, age range 36–57 years) and a senior group (n?=?31, age range 70–78 years). All children were demonstrated to be non-snorers by polysomnography (PSG). MRI scans were performed on all subjects in a state of wakefulness using a custom-made instrument.

Results

In addition to the total airway volume (p?=?0.000), the volume of each airway region was significantly smaller in children than in adults. Although the minimum cross-sectional area of the airway in children was usually measured in the velopharynx, it located to the nasopharynx in 7.14?% of cases. However, the nasopharynx continued to increase in size with increasing age.

Conclusion

Like many other physical parameters, the upper airway is significantly smaller in children than adults. The upper airway of children might be affected by the pharyngeal lymphatic ring. An increase in size of the nasopharynx was not only an age-related change, but probably also represents an anatomic advancement in non-snoring subjects.