Abstracts from other journals

The aim of the present study was to clinically evaluate fissure sealants on the occlusal fissures and buccal pits of permanent first and second molars after 20 and 15 years, respectively. The population consisted of 72 children, each of whom had had their four first molars sealed between 1977 and 1980. At the annual examinations, all caries-free, newly erupted second molars were sealed. When sealant was applied to the second molars, the first molars were checked and sealant was reapplied to those that had deficient sealants. At the follow-up, when the subjects were 26–27 years of age, 27 in the original group had moved from the community. Thus, the present result is based on 45 subjects. One hundred and fifty-three sealed first molars and 161 sealed second molars were available for inspection. At the follow-up examination of the first molars 20 years after sealant had been applied, 65% showed complete retention, 22% partial retention without caries, and 1306 caries or restoration in the occlusal fissures or buccal pits. At the 15-year follow-up of the second molars, the corresponding figures were 65%, 30% and 5%, respectively. Of the restored or carious molars, significantly more were found in the mandible than in the maxilla ( P  < 0.001). This longitudinal study showed that pit and fissure sealants, applied during childhood, have a long-lasting, caries-preventive effect.     

Awareness of and attitudes towards infertility and its treatment： a cross-sectional survey of men in a United States primary care population

Previous studies have described racial and socioeconomic disparities in the treatment of infertility. Patient factors such as attitudes and awareness may be contributing factors. Since primary care is often the setting that serves as an entry into other areas of medicine, we sought to evaluate men＇s attitudes and awareness of male infertility in the primary care setting. To do this, we performed a cross-sectional survey of men＇s attitudes toward men＇s health issues in 210 men from two primary care clinic waiting rooms in Atlanta, Georgia. The survey was self-administered with closed-ended question items and was approximately 20 min in length. Of the 310 men approached, 210 agreed to participate and returned completed surveys. Overall, 52% of men said they were ＂very＂ or ＂somewhat＂ familiar with infertility and 25% were familiar with treatments for infertility. Some men had heard of surgery （21%） and medication （35%） as treatments for male infertility. Awareness and familiarity with the condition was greater in high socioeconomic status men （i.e. college graduates or those with income 〉$100 k per year） but did not differ by race on multivariate analysis. Attitudes toward infertility varied by race with non-Caucasian men being more likely to indicate that infertility is a serious condition, to be concerned about infertility, and to believe it decreases a man＇s quality-of-life. Therefore, a lack of awareness, but not negative attitudes, may contribute to previously-described disparities in the treatment of infertility.     

Influx of Thyroid Hormones into Rat Liver In Vivo: DIFFERENTIAL AVAILABILITY OF THYROXINE AND TRIIODOTHYRONINE BOUND BY PLASMA PROTEINS

The transport of [¹²⁵I]thyroxine (T₄) and [¹²⁵I]triiodothyronine (T₃) into liver was investigated with a tissue sampling-portal vein injection technique in the anesthetized rat. The method allows the investigation of the effects of plasma proteins in human serum on the unidirectional influx of T₄ or T₃ into liver cells. The percent extraction of unidirectional clearance of T₃ and T₄ was 77±2% and 43±2%, respectively, after portal injection of a bolus of Ringer's solution. Cell membrane transport of T₄ or T₃ was nonsaturable because 50-μM concentrations of unlabeled hormone had no effect on transport. The addition of bovine albumin in concentrations of 1, 5, or 10 g/100 ml bound >98% of T₄ or T₃ in vitro, but had no significant effect on T₃ or T₄ transport in vivo. Conversely, 10% rabbit antisera specific for T₃ or T₄, completely abolished the intracellular distribution of thyroid hormone into liver. In the presence of rat serum, which contains albumin and thyroid hormone binding pre-albumin (TBPA), 18 and 81% of total plasma T₄ and T₃, respectively, were available for transport in vivo. The fraction of hormone available for transport in the presence of normal human serum, which contains albumin, TBPA, and thyroid hormone binding globulin (TBG) was 11% for T₄ and 72% for T₃. The fraction of hormone transported into liver after injection of serum obtained from pregnant or birth control pilltreated volunteers was 4% for T₄ (but this was not significantly different from zero) and 54% for T₃.     

灰色数列预测模型在成骨细胞体外培养中的应用

目的：灰色模型是运用一定的数学方法使信息不完全明确的系统经数据处理后能得到较明确结果的一种数学预测模型，体外细胞培养的影响因素较多，属于信息不完全明确的灰色系统，故运用灰色GM（1，1）模型对成骨细胞增殖、分化的变化规律进行预测，验证模型在体外细胞培养中的可应用性。方法：实验于2005—11／2006—03在广东医学院药理教研室完成。①实验过程：应用酶序列消化分离培养法培养新生大鼠颅骨成骨细胞；用MTT法测定体外培养成骨细胞在不含血清培养液A值，以了解成骨细胞的增殖情况；对硝基苯磷酸盐法观察体积分数为0．01的胎牛血清培养液对体外培养成骨细胞分泌碱性磷酸酶活性的影响，代表成骨细胞的分化情况。②灰色GM（1，1）模型建立：运用灰色系统理论，通过SAS8．1软件对体外培养成骨细胞MTT值和碱性磷酸酶OT值进行分析和预测。结果：运用灰色系统理论的后验差检验方法对模型进行检验，MTT这一指标的平均相对误差为4．4％，碱性磷酸酶这一指标的平均相对误差为7．04％，后验差比值为0．048和0．315，综合评定该模型为“好”。结论：灰色GM（1，1）模型对体外培养成骨细胞MTT值和碱性磷酸酶的OT值变化的预测精度高，结果可靠。体外培养成骨细胞MTT值和碱性磷酸酶的OT值的变化可用灰色GM（1，1）模型进行预测。     

不同孔径纳米羟基磷灰石人工骨修复兔桡骨缺损效果比较

目的:纳米级的羟基磷灰石材料与人体内组织成分更为相似,具有更佳的生物性能。评价不同孔径的多孔纳米羟基磷灰石人工骨的骨缺损修复能力,从而筛选出适合的孔径以达到骨传导功能与生物力学性能的良好统一。方法:实验于2005-10/2006-10在深圳市第二人民医院中心实验室完成。①实验材料:纳米羟基磷灰石人工骨以硝酸钙和磷酸二氢铵为原料,采用溶胶-絮凝法制备粉体,运用压力成型、木模成型和浸渍成型分别制得孔隙分布均匀的孔径分别为50～150μm、100～250μm和300～500μm的多孔纳米羟基磷灰石人工骨。②实验动物:雄性新西兰大白兔60只随机分为植入50～150μm孔径材料组、植入100～250μm孔径材料组、植入300～500μm孔径材料组、空白对照组,每组15只。实验过程中对动物处置符合动物伦理学要求。③实验方法:制备双侧桡骨骨缺损动物模型,然后用3种不同孔径的纳米羟基磷灰石人工骨材料植入骨缺损处进行修复,空白对照组不植入任何材料。④实验评估:术后4,8和12周分别行大体标本观察、X射线片观察、扫描电镜观察及生物力学测试,比较各组材料修复骨缺损的能力。结果:实验动物均进入结果分析。①X射线片检查结果:术后4周、8周、12周,植入100～250μm孔径材料组X射线评分高于植入50～150μm,300～500μm孔径材料组,差异有显著性意义(P<0.05)。②生物力学检测结果:术后4周、8周、12周,植入100～250μm孔径材料组生物力学强度高于植入50～150μm,300～500μm孔径材料组,差异有显著性意义(P<0.05)。③扫描电镜观察结果:植入100～250μm孔径材料组成骨效果明显优于植入50～150μm,300～500μm孔径材料组和空白对照组。结论:纳米羟基磷灰石人工骨具有良好的成骨能力,但其骨修复能力受孔径因素的影响,孔径100～250μm的纳米羟基磷灰石人工骨材料成骨能力较好。