豚鼠耳蜗单离外毛细胞外向钾电流的特性

目的：探讨豚鼠耳蜗单离外毛细胞（ＯＨＣ）钾电流（Ｉｋ）的正常值及其特性。方法：应用膜片钳全细胞记录技术及多种辅助方法,测试在不同细胞内、外液和电压刺激条件下的Ｉｋ、钾尾电流（Ｉｋｔａｉｌ）和反转电位。结果：Ｉｋ具有明显的电压依赖性和时间依赖性,在２０ｍｓ内达峰值,平均激活电压约为－３２．７ｍＶ,从激活电压至０电压时Ｉｋ增长最快,在４０ｍＶ时接近饱和。正常条件下Ｉｋ无明显“ｒｕｎ－ｄｏｗｎ现象”。细     

水杨酸钠对大鼠下丘神经元钾通道的抑制作用

目的了解瞬时外向钾通道和延迟整流钾通道在水杨酸钠导致耳鸣的机制中所起的作用。方法利用全细胞膜片钳技术研究水杨酸钠对急性分离的大鼠下丘神经元瞬时外向钾通道和延迟整流钾通道的影响。结果水杨酸钠能够抑制瞬时外向钾通道电流（IK（A））和延迟整流钾通道电流（IK（DR））的幅度，而且此抑制作用具有浓度依赖性（0．1～10mmol／L）。水杨酸钠抑制IK（A）和，IK（DR）的50％抑制浓度（IC50）值分别为2．27mmol／L和0．80mmol／L。1mmol／L水杨酸钠不改变，IK（A）的稳态激活曲线和稳态失活曲线的动力学特征，却将IK（DR）的稳态激活曲线和稳态失活曲线分别向超极化方向显著移动11mV和24mV。结论水杨酸钠以浓度依赖的方式抑制IK（A）和IK（DR），但是只影响IK（DR）的稳态激活和失活动力学特征。水杨酸钠对IK（A）和IK（DR）的影响，尤其对IK（DR）的影响可能与水杨酸钠导致耳鸣的机制有关。     

小鼠耳蜗螺旋神经节细胞电生理学特性的研究

目的：应用膜片钳技术记录小鼠耳蜗螺旋神经节细胞的全细胞电流,了解电压依赖性离子通道的基本电生理学特性,并比较耳蜗顶、底转螺旋神经节细胞电生理学特性的差异。方法：应用全细胞构型电压钳制技术,采用不同的电极内液及阻断剂,在不同的刺激参数下记录耳蜗顶、底转螺旋神经节细胞的电压依赖性离子通道电流,并进行分析比较。结果：实验记录到了内向的钠电流、延迟整流钾电流、超极化激活内向阳离子通道电流及瞬时外向钾电流,并发现耳蜗顶、底转螺旋神经节细胞的延迟整流钾电流及瞬时外向钾电流的电生理学特性具有显著性差异（P〈0．05）。结论：实验记录到的各种离子电流数据表明耳蜗螺旋神经节细胞具有完成动作电位的形成、传导并对其功能进行调节的离子通道基础;耳蜗顶、底转螺旋神经节细胞电生理学特性的差异有助于听觉的形成过程。     

在体耳蜗毛细胞电反应记录

为了解耳蜗内、外毛细胞基本电生理特性，建立了经耳蜗外侧壁入路在体记录耳蜗毛细胞电反应的方法，１２０只豚鼠（１２０耳）中成功记录到１８个细胞的胞内反应，对耳蜗第三回内毛细胞（ＩＨＣ）、外毛细胞（ＯＨＣ）的电生理特性进行了观察。ＩＨＣ、ＯＨＣ的静息膜电位均值分别为－３５±８．８３ｍＶ（ｎ＝３）和－７１±７．４４ｍＶ（ｎ＝７）；支持细胞负值更大。毛细胞感受器电位有交流和直流两种成分，交流反应峰－峰均值ＩＨＣ和ＯＨＣ分别为１２．４ｍＶ和５．６ｍＶ，直流成分ＩＨＣ平均为２．１６ｍＶ，ＯＨＣ平均为１．９９ｍＶ。胞内记录失败的常见原因为微电极质量较差和耳蜗外侧壁手术等造成耳蜗功能损伤。     

豚鼠耳蜗单离Deiters细胞的钾电流

目的 研究豚鼠耳蜗单离Ｄｅｉｔｅｒｓ细胞的钾电流及其特性。方法 运用膜片钳技术,在全细胞模式下记录正常细胞外液中钾电流,不同Ｋ＾＋浓度的细胞外液对细胞反转电位和外向钾电流的影响,四氨基吡啶（４－ａｍｉｎｏｐｙｒｉｄｉｎｅ,４－ＡＰ）和四乙工胺（ｔｅｔｒａｅｔｈｙｌａｍｍｏｎｉｕｍ,ＴＥＡ）对钾电流成分的阻滞作用,探讨外向钾流通道的激活和失活动力学。结果 单离Ｄｅｉｔｅｒｓ细胞具有电压依赖的外向整流     

链霉素对豚鼠耳蜗外毛细胞离子电流的影响

使用全细胞式记录膜片钳技术，研究链霉素对豚鼠耳蜗外毛细胞离子电流的影响。结果显示：１ｍｍｏｌ／Ｌ链霉素分别使钾电流和钙电流减少；链霉素对电压依赖性钙电流的半数抑制浓度为５６．０８μｍｏｌ／Ｌ，最大抑制率为２１．７％，表明链霉素以浓度依赖性方式，部分不可逆地阻断豚鼠耳蜗外毛细胞电压依赖性钙电流，对钾电流的阻滞作用部分是阻断Ｃａ＾２＋内流的结果。     

豚鼠耳蜗单离Hensen细胞钾电流特性及三磷酸腺苷对其影响

目的 研究豚鼠耳蜗单离Hensen细胞的钾离子电流及其特性以及三磷酸腺苷(adenosine triphosphate，ATP)对Hensen细胞电生理特性的影响。方法 采用传统全细胞膜片钳技术，对单离Hensen细胞进行记录。ATP通过压力注射仪对单离Hensen细胞给药。结果 Hensen细胞的钾电流呈明显的外向整流性，只有延迟整流性钾电流(delayed rectification potassiu mcurrent，IK)，没有瞬间外向性钾电流(transient outward potassium current，IA)。低浓度(0．1μmol/L，1μmol／L，10μmol／L)ATP可以使Hensen细胞的钾电流的幅度明显降低，且呈浓度依赖性，浓度越高，降幅越大。高浓度ATP(100μmol／L，1mmoL／L，10mmol／L)可以引起Hensen细胞的内向离子流，呈浓度依赖性，浓度越高，升幅越大。ATP的这两种作用均可被ATP受体拮抗剂(100μmol／L舒拉明)所逆转。结论 对Hensen细胞不同电压的刺激可以诱发出延迟整流性钾电流，低浓度ATP对Hensen细胞的钾电流有明显抑制作用，且呈浓度依赖性。高浓度ATP可以引起Hensen细胞的非选择性内向离子流，为钾离子依赖性，而且是通过ATP受体起作用。     

豚鼠耳蜗单离外毛细胞的外向整流钾电流

目的 :观察豚鼠耳蜗单离外毛细胞 (OHC)的电生理特性 ,记录不同长度OHC的外向整流钾电流 ,分析区分外向整流钾电流所包含的通道电流成分 ,研究外向整流钾电流的动力学特征。方法 :采用酶消化法及机械分离OHC。运用全细胞膜片钳技术 ,在电压钳下记录K+ 通道电流。结果 :OHC的全细胞膜电容为 (30 .96±2 .79) pF(n =2 9) ,零电流电位 (30± 2 .1)mV(n =16 ) ,反转电位为 (- 5 1.6 7± 1.84 )mV(n =9)。不同长度OHC的外向整流钾电流存在系统差异 ,短OHC表现出大的钾电导 ,长OHC则相反。 10 0 μmol/L的氯化镉 (Cd Cl2 )抑制了OHC外向整流钾电流的最大电流幅度的 6 0 % ,且改变了电流的动力学特征 ,对峰电流的影响明显大于稳态电流 (P<0 .0 1,n =5 ) ;1mmol/L的四氨基吡啶 (4 AP)抑制了最大电流幅度的 4 3% ,没有改变电流的动力学特征。外向整流钾电流的激活符合Boltzmann方程 ,V1/ 2 =(- 11.0 7± 0 .2 6 )mV ,S =(6 .6 2± 1.74 )mV(n=13)。结论 :外向整流钾电流包含有钙离子激活的钾离子电流、外向延迟整流钾电流和A型电流     

豚鼠耳蜗血管纹边缘细胞钾离子通道特性的研究

目的 研究单个豚鼠耳蜗血管纹边缘细胞的基本电生理特性。方法 应用耳蜗血管纹组织块培养技术和全细胞膜片钳技术，观察单个培养的豚鼠血管纹边缘细胞在电压钳模式下的电流特性。结果 边缘细胞上记录到钾离子电流，该钾通道有以下特性：①具有电压依赖性；②通道的活动可被4-氨基吡啶（4-aminopyridine，4-AP）和四乙铵（tetraethylammonium，TEA）在相对高浓度下阻滞；③细胞外钙离子浓度的减少可导致该钾通道电流的降低。结论 豚鼠耳蜗血管纹边缘细胞钾离子通道电流包括钙离子依赖性钾电流、外向延迟整流钾电流和A型钾电流。     

顺铂对大鼠耳蜗螺旋神经节细胞外向延迟整流钾电流的影响

目的:观察记录顺铂作用下急性分离新生大鼠耳蜗螺旋神经节细胞(SGNs)延迟整流钾通道的电流曲线,分析顺铂对SGNs钾电流激活动力学的影响,并初步探讨其耳毒性机制。方法:采用全细胞膜片钳技术记录SGNs外向延迟整流钾电流及顺铂对此电流的影响。结果:钳制电压为-60mV,刺激电压从-60mV到 80mV逐渐去极化,阶跃电压为10mV,持续时间为500ms,可在SGNs上记录到外向钾电流,该电流对TEA-Cl(4-乙基胺)敏感,具有延迟整流特性;在细胞外液中加入10μmol/L顺铂,能明显抑制SGNs延迟整流钾电流;顺铂对此电流的抑制作用与细胞外液中顺铂的浓度呈剂量依赖性;外液洗脱后SGNs电流可基本恢复正常。结论:钾通道与SGNs动作电位的产生密切相关,顺铂可抑制SGNs钾通道电流,导致听觉功能障碍。     

Results of an evaluation of clinical practice in orthognathic surgery in France in 2002

BACKGROUND: Over the years, orthognathic surgery has become a mainstay of maxillofacial surgery and is the object of many publications and oral communications. However, in spite of well-established methodology, disparities still exist in France basically concerning the way orthognathic surgery is performed. MATERIALS AND METHODS: In relation with the XXXIXth congress of Stomatology and Maxillofacial surgery, a questionnaire was mailed to 100 French maxillofacial surgeons. Questions dealing with some practical points of orthognathic surgery (condylar positioning, osteosynthesis technique, rate of condylar resorption.) were asked. RESULTS: Overall reply rate was 37%. Condylar positioning was performed empirically in 73% of the cases. Mandibular osteosynthesis was achieved by titanium miniplates alone in 70%. Post-operative condylar resorption rate was about 2%. This survey produced numerous astute comments. DISCUSSION: This survey highlighted the interest of maxillofacial surgeons for practical aspects of orthognathic surgery including the questions of condylar positioning or osteosynthesis technique. These points are instrumental in achieving high-quality surgical result.     

Efficacy of Curcumin in the healing of paracentesis in rats

Objectives

The present study was designed to investigate the possible beneficial effect of Curcumin (CMN) in healing of paracentesis in terms of wound thickness, sclerosis and closure by histological evaluation. To evaluate the efficacy of CMN, paracentesis was performed experimentally in the rats; and the results were presented histologically.

Methods

Sixteen, each 270–310 g weighted, healthy Sprague-Dawley female rats were included into the study. In both groups, paracentesis was performed into the eardrum bilaterally. In Group 1 (Paracentesis + Saline Group), saline drop was applied; and in Group 2 (Paracentesis + Curcumin group), Curcumin drop treatment was applied. Paracentesis area did not healed bilaterally in two rats (one in Group 1 and one in Group 2). Therefore, these two rats were excluded from the study. Histological examination performed in 14 rats and 28 temporal bones on the 15th day after the completion of drop treatment and closure of the paracentesis-area and wound healing were evaluated according to the histological examination criteria: Thickening of the tympanic membrane (ThicTM); and sclerosis.

Results

Both tympanic membrane thickening and sclerosis values of Paracentesis + Curcumin Group (Group 2) were significantly lower than those of the Paracentesis + Saline Group's (median: 2.0) (p = 0.001). Histological examination by light microscopy showed that in Paracentesis + Curcumin Group (Group 2), the structure of the tympanic membrane is near to the normal and decreased sclerosis was observed in connective tissue. Whereas in Paracentesis + Saline Group (Group 1), tympanic membrane thickening and connective tissue sclerosis were observed.

Conclusions

Curcumin improves wound healing process in paracentesis of TM. By using Curcumin drops, the closured paracentesis area was observed near to the normal eardrum; and thickness of the TM and sclerosis were less than the control, showing the improved healing at 15th day. The possible mechanisms may be anti-inflammatory effect, improving collagen deposition, and increasing fibroblast and vascular density in wounds thereby enhancing impaired wound healing.     

Use of ultrasound in detection of sinus disease in children

A prospective study utilizing a small, portable A-Mode ultrasound apparatus (Sinus-V 2500 Radionics Medical) was undertaken to screen children with signs and symptoms of sinusitis. Fifty-three children (age 2-16 years) were tested both by ultrasound and compared to standard radiographs of the paranasal sinuses. The sensitivity of the ultrasound to evaluate small, developing paranasal sinuses in children was low (22%). Sinus pathology, particularly mucosal thickening, was difficult to confirm. However, even opacified sinuses were only detectable in 58% of the time. Therefore, portable ultrasound devices to detect sinus disease in children, have limited usefulness for this particular population.