环境危险因素和代谢酶基因多态性与白血病关系的研究

[目的]研究环境危险因素和代谢酶基因多态性及其交互作用与白血病发生的关系。[方法]通过1：1配对病例-对照研究，对用药史、家居附近三废污染、职业暴露史、家居装潢史、吸烟史、染发史等相关因素进行调查；同时运用PCR技术，检测病例与对照的CYP1A1、GSTT1、GSTM1基因型，并分析基因．环境之间的交互作用。[结果]暴露染发年限(OR：2．182，95％CI：1．224～3．828)和装修后入住间隔(OR：1．665，95％CI：1．069～2．529)是白血病发生的危险因素；CYP1A1突变型(P=0．0235)与GSTT1缺失型基因(P=0．0042)可能增加患白血病的危险，而且与染发史或装修史存在交互作用。[结论]暴露干染发或装修，同时存在CYP1A1突变型基因或GSTT1缺失型基因可能增加白血病发生的危险性。     

噪声习服对听觉损伤保护作用

目的探讨噪声习服对听觉损伤的保护作用。方法取健康成年豚鼠40只，随机分为正常对照组、噪声习服组、噪声损伤暴露组和噪声习服后损伤暴露组。建立噪声习服实验动物模型。采用听觉电生理测试和耳蜗基底膜铺片的方法，分别测定听性脑干反应（ABR）阈值及毛细胞缺失率的变化。结果噪声习服暴露对其后强噪声损伤暴露引起的听力损失产生了13dB的保护作用。耳蜗基底膜铺片显示，本实验中暴露引起的毛细胞缺失较明显，习服后损伤暴露组与直接损伤的暴露组相比基底膜第Ⅰ、Ⅱ圈的毛细胞缺失减少。结论采用适宜的噪声暴露参数，噪声习服暴露可对其后强噪声损伤暴露引起的听力损失产生保护作用。噪声暴露引起的毛细胞形态学改变包括细胞缺失和非致死性细胞损伤。噪声习服暴露后减少其后强噪声损伤暴露引起的毛细胞缺失。     

中等强度冲击波负压暴露后豚鼠耳蜗毛细胞核形态学观察

目的观察冲击波负压(BUP)暴露后早期豚鼠耳蜗毛细胞胞核的病理形态学变化。方法将豚鼠在负压峰值为-44.5~-48.8kPa的中等强度BUP暴露3次,于BUP暴露后7d解剖取出耳蜗,应用DNA荧光染料Hoechst 33342显示毛细胞核,在荧光显微镜下毛细胞病理损害情况并进行计数。结果BUP暴露后7d,豚鼠耳蜗毛细胞可见胞核肿胀、胞核缺失、胞核固缩3种病变,以核肿胀发生最高,其次是核缺失,核固缩最为少见,3种病变的总发生率达(17.3±3.2)%,明显高于正常对照组(P<0.001)。结论BUP暴露可导致耳蜗外毛细胞核明显的病理性改变,这种改变可能是造成听力损失的主要原因之一。     

豚鼠冲击波负压暴露后耳蜗毛细胞扫描电镜和透射电镜观察

目的 探讨冲击波负压(BUP)暴露后豚鼠耳蜗毛细胞的超微结构变化特点.方法 将豚鼠暴露于不同强度的实验性BUP 1次,8h～7d后应用扫描电镜和透射电镜技术观察耳蜗基底膜毛细胞的超微结构变化.结果 负压峰值为-22.4 ～-63.3kPa的BUP暴露后,豚鼠耳蜗毛细胞的超微结构变化发生了不同程度的病理性改变,主要表现为第2、3排外毛细胞散在性缺失,甚至节段性外毛细胞缺失、纤毛融合甚至巨纤毛形成及胞浆溢出,纤毛内微丝解聚、线粒体肿胀、溶酶体数量增多和胞浆内空泡形成.结论 不同强度的BUP暴露可导致豚鼠耳蜗毛细胞的超微结构病变,且BUP强度越高,病变越重.     

Behavioral and pathological effects in the rat define two groups of neurotoxic nitriles.

Adult male Long-Evans rats (250-350 g) received control vehicles, 3,3'-iminodipropionitrile (IDPN, 400 mg kg(-1) day(-1)), allylnitrile (50 mg kg(-1) day(-1)), cis-crotononitrile (110 mg kg(-1) day(-1)), trans-crotononitrile (250 mg kg(-1) day(-1)), or 2,4-hexadienenitrile (300 mg kg(-1) day(-1)), i.p., for 3 consecutive days. Rats treated with IDPN, allylnitrile, and cis-crotononitrile developed the ECC (excitation with circling and choreiform movements) syndrome, whereas those treated with trans-crotononitrile and hexadienenitrile exhibited a different syndrome, characterized by faltering movements. On quantitative analysis, IDPN, allylnitrile, and cis-crotononitrile induced high scores in a test battery for vestibular dysfunction and hyperactivity in the open field, but they did not significantly decrease stride length. Hexadienenitrile and trans-crotononitrile did not increase the vestibular scores or the locomotor activity, but they caused a marked decrease in stride length; they also decreased holding time on a vertical ladder. In brain and spinal cord tissue from rats exposed to IDPN, allylnitrile, or cis-crotononitrile, Fluoro-Jade B, a selective stain for degenerating neurons, did not reveal any labeling other than that of nerve terminals in the glomeruli of the olfactory bulbs, indicating degeneration of the olfactory mucosa. With the same stain, rats exposed to trans-crotononitrile or hexadienenitrile showed a common pattern of selective neurotoxicity; major targets were the inferior olive and the piriform cortex. Hexadienenitrile did not cause hair cell degeneration in the vestibular and auditory sensory epithelia. Present and previous data indicate that neurotoxic nitriles induce one or the other of two different motor syndromes, through either vestibular hair cell degeneration or neuronal degeneration of the inferior olive.     

Histopathologic diagnosis of multifactorial alopecia

Establishing a definitive diagnosis for any form of alopecia can be challenging. Adding to the diagnostic complexity is the fact that many patients have more than one form of alopecia contributing to their hair loss. We conducted a review of 1360 consecutive scalp biopsy specimens submitted for the evaluation of scalp hair loss over a 16‐month period, demonstrating that 12.5% of cases had a combination of diagnoses (multifactorial alopecia) accounting for their hair loss. An approach to the histopathologic diagnosis of multifactorial alopecia, particularly multiple forms of alopecia found in a single biopsy, is here presented.     

Reliability of the pattern hair loss classifications: A comparison of the basic and specific and Norwood–Hamilton classifications

Pattern hair loss (PHL) is the most common form of baldness in both sexes. The Norwood–Hamilton classification is the most commonly used classification worldwide, but it has many limitations. The basic and specific (BASP) classification was introduced as an improvement over the Norwood–Hamilton classification. Previous research was done to estimate the reliability of the Norwood–Hamilton classification and the result was unsatisfactory. However, the reliability of the BASP and Norwood–Hamilton classifications has not yet been compared. Eight dermatological specialists, 17 dermatological residents and 15 general physicians classified PHL in 100 sets of photographs using both the BASP and Norwood–Hamilton classifications. Intergroup reproducibility was evaluated by examining the match rate of the individual data in each group and the match rate between hair specialist and the other examiners. Intragroup repeatability was determined by calculating the match rate between the first and second studies. In terms of intergroup reproducibility of the match rate for individual data in each group, the basic type had the best agreement, the specific type had the second best, and the Norwood–Hamilton classification had the lowest match rate. In comparison, hair specialist and intragroup repeatability showed the same patterns. The BASP classification not only distinguishes all kinds of hair loss patterns, but also has better reproducibility and repeatability than the Norwood–Hamilton classification.     

Guidelines for laser hair removal

Requests for removal of unwanted body hair are common in dermatologic and surgical practices. Technology continues to improve the achievement of a more permanent reduction through the use of lasers. Despite the increased use of lasers, to date, few guidelines exist in terms of how to approach laser hair removal. Specifically, one must understand the mechanism of hair growth and how lasers work to target the hair follicle. There is significant variation among practitioners in pre‐and post‐laser recommendations to patients as well as intervals between treatment sessions. We performed a thorough review of the literature in order to determine evidence for the ideal interval between treatment sessions and the ideal number of sessions. We also sought to establish, based on published reports, the recommendations for shaving, plucking, waxing or other hair removal methods prior to laser hair removal and the guidelines for sun exposure before and after laser treatments. Finally, we searched the literature to find out whether there are areas that should not be treated with laser hair removal. The evidence and recommendations in this article aim to help guide practitioners in their approach to laser hair removal.