Afferent and efferent innervation of the guinea-pig cochlea: a light microscopic and histochemical study.

The pattern of innervation of the normal and de-efferented guinea-pig cochlea has been studied from sections prepared without dehydration or decalcification procedures. This technique has given very good preservation of fine structure, thus enabling us to observe the existence of fibre routes not before described. Tissue was treated by various techniques: osmic acid fixation alone, formalin followed by either Holmes or Bielschowsky-Gros silver stains, or by Karnovsky-Roots acetylcholinesterase or a modified Maillet zinc iodide histochemical reaction. We have been able to visualize two routes which efferent fibres take to the Hensen cells, as well as connections to the efferent network under the three rows of outer hair cells. The tunnel fibres are shown to cross to three levels of a plaque on the outer hair cell-1/Deiters' cell-1 surface. The medial tunnel fibres degenerate rapidly after olivocochlear bundle section; the ‘efferent’ stained basilar fibres remain intact. ‘Efferent’ fibres are seen among the outer spiral bundle and which can take a different route from the afferent component. These newly described routes to the Deiters' and Hensen cells now pose the question whether the role of these ‘supporting’ cells is really a passive one, as has been assumed in the past.     

In utero exposure to lead and cord blood total IgE. Is there a connection?

BACKGROUND: Lead exposure and total immunoglobulin E (IgE) have been shown to be positively related in animals and humans even at lead levels below those recognized as toxic. In the last decades, exposure to lead has become more frequent in urban areas of industrialized as well as of developing countries where IgE-mediated allergy prevalence has also increased. METHODS: We examined for the first time the relationship between in utero exposure to lead and cord blood total IgE in two samples of 137 and 237 mother-newborn pairs, respectively, recruited in Paris. RESULTS: Cord blood IgE was positively related to hair lead level at birth, providing an integrated measure of long-term exposure in utero, in each cohort (Spearman's coefficient r = 0.32, P < 0.001 and r = 0.19, P < 0.01, respectively) and in the combined cohort (r = 0.21; P < 0.01). The relationship appeared to be more pronounced in newborns of nonallergic mothers (r = 0.24; P < 0.01) than in those of allergic mothers (r = 0.12). This could be due to the fact that familial history of allergy, the strongest determinant of IgE development, may overshadow the influence of lead on IgE in the offspring. CONCLUSIONS: Our findings suggest a possible intervention of environmental exposure besides genetic factors in early life development of IgE production. Further studies are needed to confirm the finding.     

含人发角蛋白和胶原的真皮类似物的研究

目的　以大鼠为动物模型 ,探讨由人发角蛋白和胶原组成的真皮类似物植入体内后真皮重建过程中的形态学变化。方法　将含人发的活性皮肤替代物植入大鼠皮下 ,于术后不同时间取出植入物及其周围组织 ,作组织学和免疫组化观察。结果　术后 4天 ,为急性炎症期 ,同时可见有约 1/2的内皮细胞以及成纤维细胞等 ;术后第 7天 ,植入物内可见大量的血管及其他迁入的细胞 ;第 3周人发开始降解 ,出现胶原纤维 ;6周后 ,人发碎裂降解 ,胶原纤维粗大 ,集结成束 ,与真皮胶原无明显区别。结论　组织学的结果显示人发可以作为真皮基质来修复皮肤缺损     

太空发育鸡胚的前庭感受器细胞形态学研究

为了探讨太空微重力对鸡胚前庭感觉上皮细胞的形态发育的影响 ,选取在航天飞机 (STS-2 9)发育鸡胚和地面发育鸡胚各两只 ,利用计算机显微测量技术分别测量椭圆囊和球囊的毛细胞、支持细胞核的切面面积、周长、形状系数。太空发育鸡胚的球囊支持细胞核的切面面积、周长显著大于地面组 ,形状系数无差异 ;太空发育鸡胚的椭圆囊支持细胞核的切面面积、周长、形状系数以及椭圆囊和球囊毛细胞的切面面积、周长与地面发育鸡胚相比无明显差异。微重力可能对球囊支持细胞核的体积发育有影响 ,对椭圆囊和球囊的毛细胞以及椭圆囊支持细胞核的形态发育无影响。     

Dll3 is expressed in developing hair cells in the mammalian cochlea.

Notch mediates the process of lateral inhibition that controls the production of hair cells in the inner ear. Hair cells are known to express Notch ligands Dll1 and Jag2, which signal through Notch1 in adjacent supporting cells. However, recent genetic and pharmacological studies indicate that the level of Notch-mediated lateral inhibition is greater than can be accounted for by Dll1 and Jag2. Here, we report that another Notch ligand, Dll3, is expressed in developing hair cells, in a pattern that overlaps that of Dll1 and Jag2. We analyzed the cochleae of Dll3(pu) mutant mice, but did not detect any abnormalities. However, earlier studies have demonstrated that there is functional redundancy among Notch ligands in cochlear development and loss of one ligand can be at least partially compensated for by another. Thus Dll3 may play a role in lateral inhibition similar to that of Dll1 and Jag2.     

Trichothiodystrophy type 4 in an Indian family

Trichothiodystrophy, non‐photosensitive type 4 (TTD4), is a rare genetic disorder with an autosomal recessive mode of inheritance. It is characterized by coarse and brittle hair, anomalies of the tissues derived from the neuro‐ectoderm (skin, hair, and nails) and intellectual disability. We herein report two male siblings aged 13 and 16 years with TTD4 and a known homozygous pathogenic variant, c.229del [p.(Arg77Glyfs*76)] in exon 1 of MPLKIP (NM_138701.3). We herein highlight the clinical and molecular findings of the first reported case of TTD4 in probands of Indian ethnicity.     

Removal Tools are Faster and Produce Less Force and Torque on the Helmet Than Cutting Tools During Face-Mask Retraction

OBJECTIVE: To investigate the retraction time, forces, and torques applied to the football helmet during removal of the face mask with different face-mask removal tools. DESIGN AND SETTING: Subjects retracted the face mask of a football helmet mounted to a force platform in a laboratory setting. They removed a standard face mask by cutting or removing (or both) the lateral plastic loop straps using 4 different tools: the Trainer's Angel (TA), FM Extractor (FM), power screwdriver (SD), and Quick Release System (QR) in a counterbalanced fashion. SUBJECTS: Eighteen certified athletic trainers participated in this study. MEASUREMENTS: We started measuring time when the subject picked up the tool and ended when the face mask was in a fully retracted position. Maximum forces and torques were measured from the force platform during the retraction process. RESULTS: The SD and QR retracted the face mask significantly faster than the TA and FM. Forces producing superior-inferior translation were least with the SD. The SD and QR produced less lateral translation and rotation and lateral flexion moment than the TA and FM. The FM produced less torque in the lateral flexion moment than the TA. CONCLUSIONS: Tools that removed the loop straps (SD, QR) were faster and produced less force and torque on the helmet than the tools that cut through the loop straps (TA, FM).     

On-line respiratory artefact removal via adaptive FIR filters in rheopneumographic measurement

Impedance rheopneumography is a simple non-invasive technique that can reflect the vascular condition in the human pulmonary circulatory system. However, the much larger and almost in-banding respiratory artefact present has greatly restricted its usefulness to only respiratory patients of a less severe type, in view of the existing practice of requiring the subject to stop breathing momentarily during measurement. Conventional fixed or adaptive filtering cannot satisfactorily remove the artefact in view of the non-time stationary characteristic of the latter. In the paper, a fast adaptive FIR filter design method, which is based on the filter coefficient look-up table (CLT) concept, is presented as a solution. The CLT is constructed with the coefficients indexed to the cut-off frequency to separate the two components of the plethysmogram. An on-line fast Fourier transform is calculated to track the cut-off frequency. This filter can adaptively change its coefficients, not only for different subjects, but also for the same subject during long-term monitoring. Results show that this filter design is capable of providing an almost respiratory artefact-free signal for a majority of patients. The high speed of implementation also renders it a possibility for real-time monitoring applications.     

Lactate kinetics during passive and partially active recovery in endurance and sprint athletes

We investigated the effects of passive and partially active recovery on lactate removal after exhausting cycle ergometer exercise in endurance and sprint athletes. A group of 14 men, 7 endurance-trained (ET) and 7 sprint-trained (ST), performed two maximal incremental exercise tests followed by either passive recovery (20 min seated on cycle ergometer followed by 40 min more of seated rest) or partially active recovery [20 min of pedalling at 40% maximal oxygen uptake ( O_2max) followed by 40 min of seated rest]. Venous blood samples were drawn at 5 min and 1 min prior to exercise, at the end of exercise, and during recovery at 1, 2, 3, 4, 5, 6, 8, 10, 15, 20, 30, 40, 50, 60 min post-exercise. The time course of changes in lactate concentration during the recovery phases were fitted by a bi-exponential time function to assess the velocity constant of the slowly decreasing component (₂) expressing the rate of blood lactate removal. The results showed that at the end of maximal exercise and during the 1st min of recovery, ET showed higher blood lactate concentrations than ST. Furthermore, ET reached significantly higher maximal exercise intensities [5.1 (SEM 0.5) W · kg^–1 vs 4.0 (SEM 0.3) W · kg^–1,P < 0.05] and O_2max [68.4 (SEM 1.1) ml · kg^–1 · min^–1 vs 55.5 (SEM 5.1) ml · kg^–1 · min^–1,P < 0.01]. There was no significant difference between the two groups during passive recovery for ₂ During partially active recovery, ₂ was higher than during passive recovery for both groups (P < 0.001), but ET recovered faster and sooner than ST (P < 0.05). Compared to passive recovery, the ₂ measured during partially active recovery was increased threefold in ET and only 1.5-fold in ST. We concluded that partially active recovery potentiates the enhanced ability to remove blood lactate induced by endurance training.     

白发与黑发的微量元素分析

本文应用EPM-810Q电子探针,对53例35～60岁健康成年人白发与黑发(指长在同一部位、相邻单根白发与黑发),进行微量元素分析,结果表明:白发中Mg、Al、Cd、Ca、Cr、Mn、Fe、Se微量元素含量明显小于黑发,而Cu、Zn、Pb元素含量大于黑发。以上差异有显著性意义(P<0.001),并对上述差异进行了讨论。