Parent–child separation: the relationship between separation and psychological adjustment among Chinese rural children

Purpose

The current study aimed to explore the characteristics of psychological adjustment among Chinese left-behind children (LBC) in rural areas, and to examine the association between separation duration from parent/parents (SDP) and children’s psychological adjustment and the extent to which personality mediates this hypothesized link.

Methods

We surveyed 534 rural children and adolescents aged 10–17 years at school (440 LBC and 94 non-LBC) in 2013, who were selected for participation using stratified cluster sampling from two counties in Chongqing, China. Measures used included socio-demographic variables, age at the commencement and end of the separation from parents, the revised Chinese Juvenile Eysenck Personality Questionnaire, and the Adolescent Psychological Adaptability Scale.

Results

Most children (82.4%) had experienced separation from parents. t test results showed a marginally significant difference (p?=?.08) in psychological adjustment between LBC (mean?=?64.44, SD?=?8.62) and non-LBC (mean?=?66.16, SD?=?9.26). LBC’s mean SDP was 5.64 years (SD?=?3.90). Correlation analysis showed that children’s SDP was negatively associated with psychological adjustment. Structural equation modeling showed that neuroticism, but not extraversion or psychoticism, fully mediated the link between children’s SDP and psychological adjustment.

Conclusion

Personality (neuroticism) is one of the mediating pathways through which long-term SDP may predict poor psychological adjustment among children. Given the detrimental impact of long-term SDP, interventions should target the mediating pathway to buffer against the negative impact of parental separation on the affected rural children and to improve their mental health.

     

Inhibitory effect of synthetic histatin 5 on leukotoxin from Actinobacillus actinomycetemcomitans

Actinobacillus actinomycetemcomitans is a gram-negative bacterium strongly implicated in the pathogenesis of juvenile periodontitis. This periodontal pathogen synthesizes a leukotoxin that destroys human polymorphonuclear leukocytes (PMNs), and this toxin is thought to be responsible for the virulence of A. actinomycetemcomitans. It was therefore of interest to assess whether major virulence factors of periodontal pathogens were neutralized by salivary components. This study focuses on the effect of histatins, components of the nonimmune oral defense system, on leukotoxin activity. Leukotoxin was extracted with polymyxin B from freshly grown anaerobic cultures of A. actinomycetemcomitans strain Y4. PMNs isolated from blood of healthy human volunteers were incubated in a cytotoxicity assay containing PMNs (10(7) cells/ml) and leukotoxin preparation (0-500 microg/ml) in Hanks' balanced salt solution at 37 degrees C for 0-120 min with or without synthetic histatin 5 (0-500 microM). Cytotoxicity was measured by release of lactate dehydrogenase (LDH) at different time intervals. Histatin 5 neutralized the toxic effect of the leukotoxin preparation in a concentration-dependent manner, with an IC(50) value of 150 microM. When PMNs were preincubated with histatin 5 (300 microM), washed and subsequently exposed to leukotoxin, no protective effect was observed. This observation suggests a mechanism of inhibition whereby histatin 5 either directly neutralizes the leukotoxin or interferes with the leukotoxin-PMN interaction. The inhibitory effect of histatin 5 on leukotoxic activity may suggest a new biological function of histatins in the oral cavity as a naturally occurring secondary antibiotic.     

Epithelial fibroblast growth factor receptor 1 regulates enamel formation

The interaction between epithelial and mesenchymal tissues plays a critical role in the development of organs such as teeth, lungs, and hair. During tooth development, fibroblast growth factor (FGF) signaling is critical for regulating reciprocal epithelial and mesenchymal interactions. FGF signaling requires FGF ligands and their receptors (FGFRs). In this study, we investigated the role of epithelial FGF signaling in tooth development, using the Cre-loxp system to create tissue-specific inactivation of Fgfr1 in mice. In K14-Cre;Fgfr1(fl/fl) mice, the apical sides of enamel-secreting ameloblasts failed to adhere properly to each other, although ameloblast differentiation was unaffected at early stages. Prior to eruption, enamel structure was compromised in the K14-Cre;Fgfr1(fl/fl) mice and displayed severe enamel defects that mimic amelogenesis imperfecta (AI), with a rough, irregular enamel surface. These results suggest that there is a cell-autonomous requirement for FGF signaling in the dental epithelium during enamel formation. Loss of Fgfr1 affects ameloblast organization at the enamel-secretory stage and, hence, the formation of enamel.     

牵张应变作用下人牙周膜细胞内磷脂酶C-γ1水平的变化

目的:观察机械牵张应变作用下,人牙周膜细胞(HPDLCs)内磷脂酶C-γ1(PLC-γ1)水平的变化。方法:通过原代和传代培养,获得性状稳定的人牙周膜细胞,使用动态机械应变细胞加载仪对细胞进行1%、10%和20%动态牵张应变加载。加载不同时间,通过流式细胞仪对细胞进行PLC-γ1水平检测。采用SPSS13.0软件包对数据进行方差分析。结果:在加载牵张应变初期,细胞内的PLC-γ1水平维持较低水平;随着牵张应变加载时间的延长,牙周膜细胞内的PLC-γ1水平逐渐升高。50min时,PLC-γ1水平达到各应变组的最高值(P<0.01)。随着加载时间的继续延长,60min时,各应变组的PLC-γ1水平都显著下降(P<0.01)。结论:牵张应变可引起细胞内PLC-γ1水平的变化。     

云南省双江县布朗族头面部器官微机测量研究

目的 对云南省双江县邦丙乡布朗族头面部器官进行全面系统地测量研究。方法 采用自行研制的头面部摄相—计算机测量系统，对正常布朗族成人155人进行了头面部器官全面系统的测量，其中男性96人，女性59人。结果 得出了布朗族成年男女两性头面部器官41个项目测量值和17个头面部指数资料。结论 该研究委仅对临床医学和美学研究有重要意义，而且对人类学、民族学和工业等相关学科也有重要的参考价值。     

Monitoring bacterial-demineralization of human dentine by electrochemical impedance spectroscopy

Objective

The purpose of this study was two-fold: (1) to monitor bacterial biofilm formation and bacteria-induced demineralization of dentine in situ by using electrochemical impedance spectrum (EIS); (2) to examine the relationship between EIS findings and changes in the chemical composition and ultrastructure of dentine during bacteria-induced demineralization.

Methods

In this study, dentine demineralization was induced by Streptococcusmutans (ATCC 25175) in the presence of sucrose in culture medium and was monitored using two EIS measurement systems (Type A with a working electrode and Type B without a working electrode). Scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) were employed to examine the morphology, element contents and crystallinity of hydroxyapatite (HAP) on the dentine surface. Transverse microradiography (TMR) was used to characterize the lesion depth and degree of mineral loss during demineralization.

Results

The resistance of the bulk dentine (R_d) and the apparent resistance of dentine (R_a) measured from the Type A and Type B EIS systems, respectively, decreased gradually with demineralization. The resistance of the biofilm formed on dentine surface was determined by fitting the EIS data with equivalent circuits. The presence of biofilm slightly increased R_a of dentine before demineralization. However, the electrochemical behavior of biofilm did not affect the decreasing impedance of dentine with demineralization. The SEM, EDX, XRD and TMR results demonstrated that the surface and bulk dentine gradually became more porous due to the loss of minerals during demineralization, which in turn resulted in the decrease in R_d and R_a values obtained from EIS systems.

Conclusions

This investigation highlighted EIS as a potential technique to monitor biofilm formation and bacterial-induced demineralization in situ.     

健康成人刺激性全唾液流速及一氧化氮含量的增龄性变化

目的:研究不同年龄阶段健康成人的刺激性全唾液流速及唾液一氧化氮含量的变化。方法:将97例健康成人分成4个年龄组,分别为青龄组(20~39岁)、中龄组(40~59岁)、老龄组(60~79岁)、长寿组(80岁以上)。在上午8:00~10:00空腹,以2.5ml/L洗必太漱口,以20ml/L柠檬酸刺激舌背前1/3,以双蒸水漱口后采集全唾液5min,记录样本容量,并计算其流速。用硝酸还原酶法检测唾液中NO浓度,并计算其唾液中NO的单位时间含量。结果:(1)青龄组刺激性全唾液流速高于中龄组、老龄组、长寿组(P<0.05);中龄组、老龄组、长寿组之间唾液流速无显著性差异(P>0.05);(2)不同年龄组间两两比较,刺激性全唾液NO浓度无显著性差异(P>0.05);青龄组NO单位时间含量显著高于中龄组、老龄组和长寿组(P<0.05),中龄组、老龄组、长寿组之间的NO单位时间含量无显著性差异(P>0.05)。结论:(1)中老年人群的刺激性全唾液流速显著低于青年人群;(2)随年龄增长,健康成人刺激性全唾液中的NO浓度未发生明显变化,但其单位时间含量呈降低趋势。     

下颌骨恶性血管内皮与外皮瘤的临床病理观察(附4例报告)

本文根据作者经治发生于下颌骨的4个恶性血管内皮与外皮瘤病例，结合文献复习，探讨其临床病理特点、诊断治疗与预后等问题。发现该病发生于颌骨者十分罕见，临床易发生误诊，因此，临床医生遇有颌骨肿块生长迅速，疼痛呈持续性且逐渐加重，X线片提示有溶骨性破坏，诊断也应考虑患本病的可能，尽早手术治疗，并于术中行冰冻活检协诊。一般认为本病预后差，但如组织学形态分化较好，治疗及时，切除范围适当，也可获得较佳疗效。     

口腔念珠菌带菌与感染状态分离菌株的RAPD分析

目的 :研究念珠菌种之间及不同来源白念珠菌菌株之间的基因型相关性。方法 :对口腔白念珠菌病原菌、共生菌及非白念病原菌分别进行表型和RAPD分析。结果 :白念珠菌与非白念珠菌的RAPD带型存在差异 ,相似系数在 5 1.7%。共生菌与病原菌RAPD带型未见差异。白念珠菌种内相似系数大于 70 % ,菌株间存在DNA多态性。结论 :共生白念珠菌与病原菌未见RAPD带型差别 ,提示对口腔念珠菌病的防治应重视宿主因素在发病中的作用。     

远缘链球菌中葡萄糖基转移酶催化活性区基因的克隆和初步表达

目的 :构建一株高效表达Streptococcussobrinus 6715中GTF -I催化活性区 (含有B细胞表位 )多肽的菌株 ,为抗GTF -I的单克隆抗体的检测和防治龋病亚单位疫苗的研究奠定基础。方法 :提取基因组DNA ,然后用PCR技术扩增出中目的肽段的约 1.1kb编码基因 ,并将其克隆至表达载体 pGEX -4T -1中构建 pGEX -gtf表达质粒。该质粒转化大肠杆菌JM 10 9后获得重组表达菌株。PCR筛选阳性克隆子。异丙基-β -D -硫代半乳糖苷 (IPTG)诱导 ,确定含有 pGEX -gtf的大肠杆菌JM 10 9的表达情况。 结果 :含有质粒pGEX -gtf的大肠杆菌JM 10 9能够表达GST -GTF融合蛋白。 结论 :成功扩增目的基因 ,并且把它定向克隆到表达载体pGEX -4T -1中构建表达质粒 ,并且该表达质粒能在大肠杆菌中进行表达