家猫外伤性视神经病的电生理及形态学观察

目的制作外伤性视神经病（traumatic optic neuropathy，TON）动物模型，观察其电生理及形态学改变，为指导临床救治提供参考。方法选择2只成年家猫进行视神经解剖观察；选择成年家猫30只．经上颌窦和鼻腔筛蝶窦双入路，用自制视神经管损伤器在内镜监视下损伤管内段视神经，建立TON模型。观察伤后瞳孔变化，监测损伤后1h、1d、3d、1周、2周及4周时的图形翻转视觉诱发电位（pattern reversal visual evoked potential，PR—VEP）变化，并分别于损伤后1d、3d、1周、2周及4周处死动物，观察视神经组织的形态学改变。结果损伤后有8只猫患眼出现Marcus—Gunn黑朦强直性瞳孔，其余22只患眼直接和间接对光反射均不灵敏。VEP各波：1h、1d．3d、1周的N75P100、P100N145振幅降低超过50％，N75、P100及N145潜伏期延长超过10ms，2周以后的波形趋于一条直线。光镜下示视神经组织随时间推移而呈现空泡样变性，范围逐渐扩大，从伤后1d开始，视神经纤维束逐渐肿胀，纤维空泡变性；1周后空泡变性扩大为片状；至2周后出现大片空泡，并形成大空泡。电镜下示伤后1d视神经轴突内空泡变性，轴膜与髓鞘之间形成间隙，髓鞘松解；伤后3d轴突肿胀，空泡样变增多，髓鞘松解明显；伤后1周轴突髓鞘半环行套叠，泡状解离，有大量崩解产物出现，轴突呈空泡样和均质状，微丝、微管消失；伤后2周髓鞘呈现“洋葱皮”样改变；4周后髓鞘向心性扩展挤压，轴浆消失，整体崩解。结论家猫外伤性视神经病模型与临床视神经损伤具有相近的生物学特性，可以进行后续治疗等相关研究。伤后1d以上的视神经病理生理改变基本一致，只是量和度有所不同，故视神经损伤后应及早进行手术减压，以免延误最佳治疗时间。     

前庭诱发肌源性电位预测突聋患者疗效的临床价值

目的 分析单侧突发性耳聋患者的疗效,探讨前庭功能与预后的关系。 方法 回顾性分析59例(59耳)突发性耳聋患者的临床资料,观察临床疗效,根据前庭功能结果探讨对预后的影响。 结果 59例突发性耳聋患者在治疗前共进行了183项前庭功能检查,眼性前庭诱发肌源性电位(oVEMP)和颈性前庭诱发肌源性电位(cVEMP)异常的突聋患者显示出更低的治疗总有效率;oVEMP和cVEMP正常的突聋患者受损频率听力提高更明显。冷热试验(Caloric Test)和视频头脉冲试验(vHIT)的正常与否对突聋患者的总有效率和受损听力的提高无影响。cVEMP和oVEMP都异常的患者治疗无效率比仅其中一项异常的患者高,受损听力恢复程度也比仅其中一项异常的患者差。 结论 oVEMP和cVEMP异常的突聋患者疗效较差,oVEMP和cVEMP正常的突聋患者有更好的听力恢复。oVEMP和cVEMP功能可能是预测突发性聋患者预后的有效指标。前庭功能异常提示突发性聋患者的内耳病变范围较大、程度较重。     

原发性良性阵发性位置性眩晕患者VEMP异常率的临床观察

目的 比较原发性初发和复发良性阵发性位置性眩晕(BPPV)患者的前庭诱发肌源性电位(VEMPs)特点,探索原发性BPPV屡次复发的可能发病机制。 方法 收集首次就诊即确诊为单侧原发性BPPV的患者57例,其中初发患者36例,复发患者21例。所有患者均进行气导声刺激条件下的颈肌VEMP(cVEMP)和眼肌VEMP(oVEMP)检查,对比分析初发组和复发组cVEMP和oVEMP结果的差异。 结果 (1)初发和复发BPPV组在性别、发病侧别及受累半规管均无统计学差异(P>0.05),年龄存在统计学差异(P<0.05);(2)57例BPPV患者中21例(36.84%)cVEMP异常,35例(61.40%)oVEMP异常,oVEMP异常率更高(P<0.05);分别对初发组中和复发组中的cVEMP和oVEMP异常率进行比较,结果显示两组oVEMP异常率更高,差异具有统计学意义(P<0.05);(3)初发BPPV组cVEMP异常有16例(44.45%),复发BPPV组异常有5例(23.81%);初发BPPV组oVEM异常有19例(52.79%),复发BPPV组中oVEMP异常有16例(76.19%);两组cVEMP和oVEMP异常率均无统计学差异(P>0.05);(4)复发2次组和复发3次以上组,与初发组进行VEMPs异常率比较显示三组间cVEMP及oVEMP异常率均无统计学差异(P>0.05)。 结论 原发性初发组和复发组BPPV患者的cVEMP和oVEMP异常率差异均无统计学意义,提示耳石器功能异常可能不是原发性BPPV患者反复复发的发病机制。     

Mineral and bone physiology in the foetus,preterm and full-term neonates

Mother is the major source of minerals in foetal life with placenta actively transporting against a concentration and electrochemical gradient. The foetal serum mineral concentration is thereby higher as compared to maternal values, which possibly help in its rapid accretion in developing bones and for counteracting postnatal fall in calcium levels at birth. Parathyroid hormone related peptide (PTHrP) and parathyroid hormone (PTH) play a major role in mineral physiology during foetal life with hormones like calcitriol, calcitonin, FGF-23 and sex steroids having minimal role. PTHrP and PTH also play a major role in endochondral bone formation and mineralization of skeleton. At the birth, as the cord is clamped, there is loss of active transport of minerals through placenta and the neonate has to rely on enteral intake of minerals to meet the demands of growing bones and metabolisms. The calcium levels fall after birth, reaching a nadir at 24–48 h and gradually rise to adult values over several days, probably resulting from a fall in PTHrP levels and hyporesponsiveness of parathyroid glands. As PTH and calcitriol levels increase postnatally, there is a rise in calcium levels with maturation in functioning of kidneys and intestines. However, there may be significant delay in intestinal maturation in preterm infants along with an increased demand for mineral accretion, which predispose them to osteopenia of prematurity.     

Effects of noise exposure on auditory brainstem response and speech-in-noise tasks: a review of the literature

Abstract

Objective: Short-term noise exposure that induces transient changes in thresholds has induced permanent cochlear synaptopathy in multiple species. Here, the literature was reviewed to gain translational insight into the relationships between noise exposure, ABR metrics, speech-in-noise performance and TTS in humans.

Design: PubMed-based literature search, retrieval and review of full-text articles. Study Sample: Peer-reviewed literature identified using PubMed search.

Results: Permanent occupational noise-induced hearing loss (NIHL) is frequently accompanied by abnormal ABR amplitude and latency. In the absence of NIHL, there are mixed results for relationships between noise exposure and ABR metrics. Interpretation of speech-in-noise deficits is difficult as both cochlear synaptopathy and outer hair cell (OHC) loss can drive deficits. Reductions in Wave I amplitude during TTS may reflect temporary OHC pathology rather than cochlear synaptopathy. Use of diverse protocols across studies reduces the ability to compare outcomes across studies.

Conclusions: Longitudinal ABR and speech-in-noise data collected using consistent protocols are needed. Although speech-in-noise testing may not reflect cochlear synaptopathy, speech-in-noise testing should be completed as part of a comprehensive test battery to provide the objective measurement of patient difficulty.     

Role of action potential shortening in the prevention of arrhythmias in canine cardiac tissue

1. The effects of the K+ channel opener diazoxide and the oxime-containing Ca2+ and K+ channel blocker salicylaldoxime were tested in canine cardiac Purkinje tissue. 2. Both drugs shortened action potential duration (APD). For salicylaldoxime (0.1-1.0 mmol/L), the reductions in APD were statistically significant at the 25% level of repolarization (APD25) for 0.1 mmol/L (P < 0.05, n = 14) and 0.5 and 1.0 mmol/L (P < 0.01, n = 6), at the 50% level of repolarization (APD50) for 0.1 mmol/L (P < 0.05, n = 14) and 0.5 and 1.0 mmol/L (P < 0.01, n = 6) and at the 90% level of repolarization (APD90) for 0.5 and 1.0 mmol/L (P < 0.01, n = 6). In contrast, diazoxide (0.05-0.1 mmol/L) significantly shortened APD at all levels of repolarizations, with the APD50 and APD90 reduced most significantly (P < 0.01, n = 6) for higher concentrations of the drug (0.07-0.1 mmol/L). Both drugs significantly reduced the force of contraction. 3. Diazoxide (10 experiments) was more potent in suppressing strophanthidin-induced arrhythmias than salicylaldoxime (three of seven experiments). Salicylaldoxime reduced APD even further in the presence of diazoxide. 4. Although salicylaldoxime and diazoxide modulate different ion channels, it appears APD shortening may be a necessary, but insufficient, factor for the suppression of strophanthidin-induced arrhythmias.     

A population-based case-control teratologic study of oral erythromycin treatment during pregnancy

The objective of the study was to evaluate the human teratogenic potential of oral erythromycin treatment during pregnancy in the population-based dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980–1996. Of 38,151 pregnant women who had newborn infants without any congenital abnormalities (population control group), 172 (0.5%) had received erythromycin, while of 22,865 pregnant women who had newborns or fetuses with congenital abnormalities, 113 (0.5%) had been treated with erythromycin (crude OR with 95% CI = 1.1, 0.9–1.4). The case–control pair analysis did not indicate a teratogenic potential of erythromycin during the second through third months of gestation, i.e., in the critical period for most major congenital abnormalities. The frequency of maternal erythromycin treatments during the second–third months of pregnancy was also not higher in different congenital abnormality groups compared with the rate of the total control group as referent. Thus, treatment with oral erythromycin during pregnancy did not present detectable teratogenic risk to the fetus.     

Auditory function in guinea pigs treated with netilmicin and other aminoglycoside antibiotics

Summary The following aminoglycoside antibiotics netilmicin, sisomicin, gentamicin, and kanamycin were submitted to a comparative study of their ototoxicity using both reflexological (Preyer's pinnareflex) and electrophysiological (near and far field) methods. The daily s.c. administration of sisomicin, gentamicin, and kanamycin for 21 days provoked a dose-related impairment of the cochlear function, detected with all the employed techniques. On the other hand, a very low ototoxic effect of netilmicin was demonstrated with electrophysiological but not with the reflexological evaluation.The reliability of the methods used in these experiments is also compared.     

灵芝多糖引起小鼠腹腔巨噬细胞膜超极化

用激光扫描共聚焦显微 镜（ Ｌ Ｓ Ｃ Ｍ） 技 术,动态 监测了 灵芝多 糖 Ｇ Ｌ Ｐ 均 一体组 分 Ｇ Ｌ Ｂ７ 对小 鼠腹腔巨噬细胞（ ＭΦ） 膜电位（ Ｍ Ｐ） 的影 响,结 果 Ｇ Ｌ Ｂ７ 能 引起 小 鼠腹 腔 ＭΦ 膜快 速超 极化, 最 低降 低幅 度为 ３９ ±９ ％ ,之后慢慢复极,但在１０ ｍｉｎ 内未恢复至原来水平。提示灵芝多糖引起小鼠腹腔 ＭΦ 膜超极化是其信 号跨膜转导的重要机制。