Motor control of the costal and crural diaphragm--insights from transcranial magnetic stimulation in man

The costal and crural parts of the diaphragm differ in their embryological development and physiological function. It is not known if this is reflected in differences in their motor cortical representation. We compared the response of the costal and crural diaphragms using varying intensities of transcranial magnetic stimulation of the motor cortex at rest and during submaximal and maximal inspiratory efforts. The costal and crural motor evoked potential recruitment curves during submaximal inspiratory efforts were similar. The response to stimulation before, during and at 10 and 30 min after 44 consecutive maximal inspiratory efforts was also the same. Using paired stimulations to investigate intra-cortical facilitatory and inhibitory circuits we found no difference between the costal and crural response with varying interstimulus intervals, or when conditioning and test stimulus intensity were varied. We conclude that supraspinal control of the costal and crural diaphragm is identical during inspiratory tasks.     

Diaphragmatic motion in the sitting and supine positions: Healthy subject study using a vertically open magnetic resonance system

PURPOSE: To determine the postural difference of diaphragmatic motion between the sitting and supine positions. MATERIALS AND METHODS: A total of 10 healthy men were examined using a vertically open 0.5-T magnetic resonance (MR) system. A total of 40 sequential MR images were obtained in both the sitting and supine positions during two to five respiratory cycles. The diaphragmatic excursions (DEs) were measured on three diaphragmatic points of six sagittal planes for both positions. The differences in DEs between the anterior and posterior parts of the diaphragm were also determined. RESULTS: DEs in the supine position were significantly greater than those in the sitting position at 15 of the 18 points. In five of the six sagittal planes, the difference of DE between posterior and anterior points was significantly larger in the supine position than in the sitting position. CONCLUSION: Diaphragmatic movement in the supine position is greater than that in the sitting position, especially in the posterior part of the diaphragm.     

Thoracic complications during urological laparoscopy

PURPOSE: We documented thoracic related complications during urological laparoscopic surgery. MATERIALS AND METHODS: A total of 1129 patients underwent major urological laparoscopic procedures in a 5-year period. Operative reports and postoperative radiographic reports were retrospectively reviewed to identify patients with thoracic related medical and surgical sequelae. Of the patients 619 (55%) underwent at least 1 chest x-ray in the immediate or early postoperative period. In the remaining 510 patients (45%) there was no clinical indication to perform chest x-ray. RESULTS: Of 619 patients undergoing chest x-ray 438 (71%) were completely normal. Medical pulmonary complications, surgical thoracic complications and subclinical, incidentally detected gas collections in the chest were identified in 12.6%, 0.5% and 5.5% of patients, respectively. Medical complications in 12.6% of cases included pulmonary infiltrate/atelectasis in 9.7%, pleural effusion in 4.8% and pulmonary embolus in 0.3%. Surgical complications included symptomatic pneumothorax in 4 patients (0.35%), hemothorax in 1 (0.08%) and chylothorax in 1 (0.08%). Subclinical abnormal thoracic gas collections were radiographically noted in 34 of the 619 patients (5.5%) on chest x-ray, including pneumomediastinum in 19 (3.1%), pneumothorax in 10 (1.6%) and pneumopericardium in 5 (0.8%). Overall 36 of 40 (90%) thoracic surgical complications (3) and subclinical, incidentally detected gas collections (33) occurred during retroperitoneal laparoscopy. Re-intervention was necessary in 6 patients (0.5%), namely pulmonary embolus requiring vena caval filter placement in 3 (0.3%), pneumothorax requiring a chest tube in 2 (0.17%) and hemothorax requiring emergency open thoracotomy in 1 (0.08%). No patient underwent open conversion to complete the initial proposed operation. CONCLUSIONS: Due to its high solubility the expectant management of incidental CO2 pneumothorax, pneumopericardium and pneumomediastinum is recommended initially in the clinically stable patient. Inadvertent diaphragmatic entry can be satisfactorily repaired laparoscopically without open conversion. Although it is rare, surgical thoracic complications are potentially life threatening, requiring prompt identification and management.     

The primary motor area for voluntary diaphragmatic motion identified by high field fMRI

Abstract. In order to identify the precise location of the primary motor area for the diaphragm with respect to the classical motor homunculus, functional magnetic resonance imaging (fMRI) experiments were performed utilizing independent component-cross correlation- sequential epoch (ICS) analysis on a high-field (3.0 Tesla) system. Activations which correlated with voluntary diaphragmatic motion mapped onto the area anterolateral to that for voluntary hand motion (internal control in ICS analysis).Multiple subject analysis yielded the primary motor cortex for the diaphragm to be (±48, –4, 47) in the Talairach and Tournoux coordinates. The results were highly consistent with the previously reported cortical area for the diaphragm determined by transcranial electrical/magnetic stimulation.     

The acute effect of trimetazidine on the high frequency fatigue in the isolated Rat diaphragm muscle

The objective of this study was to determine the acute effect of trimetazidine (TMZ) on the pre-fatigue, fatigue and post-fatigue contractile characteristics and tension-frequency relationships of isolated rat diaphragm muscle. Muscle strips were taken from the ventral-costal aspects of the diaphragm muscle of rats killed by decapitation. The muscle strips were suspended in organ baths containing Krebs solution, with a gas mixture of 95% O2 and 5% CO2 at 37 degrees C and pH 7.35-7.45. After determining the thermoregulation and optimum muscle length the muscles were subjected to direct supramaximal stimulation with 0.05 Hz frequency square pulses for periods of 0.5 msec to obtain control values. After adding 5 x 10(-6) and 5 x 10(-5) M trimetazidine solution to the respective bath media, the contractile parameters of the muscles were recorded. The contractile parameters were also recorded for both the trimetazidine and trimetazidine-free media after application of the high frequency fatigue protocols. Later, the tension-frequency relationship was determined by applying stimulating pulses of 10, 20, 50 and 100 Hz to the muscle strips. Whilst the twitch tension obtained from the 5 x 10(-6) and 5 x 10(-5) M trimetazidine media showed numerical increases compared to that of the controls, these were not statistically significant (p>0.05). The contraction time exhibited a dose dependent increase (p<0.001), whilst the contraction and relaxation rates did not differ significantly. The isometric contraction forces obtained with the different stimulating frequencies showed a significant increase in the tetanic contraction only at 100 Hz (p<0.05). A comparison of the pre- and post-fatigue twitch tensions in the trimetazidine media showed the post- fatigue twitch tensions to be significantly higher than those of the pre-fatigue contraction forces (p<0.05). In the 5 x 10(-6) and 5 x 10(-5) M trimetazidine media the increases in the post-fatigue contraction force were 22 and 30%, respectively. These results demonstrated that in isolated rat diaphragm muscle, TMZ significantly limited the mechanical performance decrease during fatigue. It is our opinion that trimetazidine contributed to the observed fatigue tolerance by eliminating the factors of fatigue, due to preservation of intracellular calcium homeostasis, provision of the ATP energy levels needed by ATPase dependent pumps and especially by keeping the intracellular pH within certain limits.     

Causes and consequences of proteinuria: the kidney filtration barrier and progressive renal failure

The past few years have witnessed a major breakthrough in the understanding of the molecular mechanisms and ultrastructural changes behind the development of proteinuria. The discovery of several proteins in the glomerular podocyte and slit diaphragm, where mutations lead to disease, has revealed the importance of this cell with its diaphragm as the major filtration barrier as opposed to the glomerular basement membrane (GBM) previously ascribed this function. Furthermore, accumulating clinical as well as experimental evidence points to the harmful effects of proteinuria, irrespective of the original damage. The purpose of this review is to shed light on what we know today about the two sides of this 'coin', the causes and the consequences of proteinuria.     

大鼠膈肌水溶性蛋白组的研究

本研究应用蛋白组的核心技术——高分辨率二维电泳对同属骨骼肌的膈肌和趾长伸肌水溶性蛋白组的二维电泳图谱进行了比较,并对两者在老化过程与年龄相关的水溶性蛋白进行了比较。我们发现膈肌和趾长伸肌水溶性蛋白的二维图谱极为相似,大部分蛋白都能较好地重叠。我们未能找到持续而稳定且特异于膈肌的水溶性蛋白。同时我们发现了三个与年龄相关蛋白（S1,S2和S3）,随增龄,蛋白S1只在24月龄趾长伸肌存在,而在8月龄和24月龄的膈肌中却不能被检测到。S2在8月龄的膈肌和趾长伸肌存在,而在24月龄的膈肌和趾长伸肌中不能被检测到。S3在8月龄的膈肌和趾长伸肌中不能被检测,而在24月龄的膈肌和趾长伸肌中能被检测到。本研究提示膈肌和趾长伸肌水溶性蛋白在其成年时表达基本一致。老化而造成水溶性蛋白表达的变化在膈肌和趾长伸肌也较为相似。     

新斯的明拮抗银环蛇毒素对大鼠膈肌张力的影响

目的：探讨新斯的明对经银环蛇毒处理后的离体膈肌肌条张力的影响。方法：取大鼠膈肌制成实验用膈肌肌条,连接并固定于高精度张力换能器,通过桥式放大器由8导生理记录仪记录经银环蛇毒处理后的膈肌给予生理盐水、不同浓度（1、3、10μmol/ L）新斯的明,在不同时间段（5、10、15、30、60 min）张力大小。结果：10 min 后,1和3μmol/ L 浓度新斯的明组较对照组的肌力均有所恢复,但仅10μmol/ L 组与对照组差异有统计学意义（P＜0.01）;60 min 时,3μmol/ L 组与对照组的差异有统计学意义（P＜0.05）,1μmol/ L 组与对照组比较,差异无统计学意义（P＞0.05）。随新斯的明浓度增加,肌力恢复程度增加,且不同浓度组之间差异有统计学意义（P＜0.05）。结论：新斯的明能增加经银环蛇毒处理后的大鼠膈肌肌条的张力,且疗效与剂量有关系。     

膈肌包埋法救治重度肝破裂出血的护理体会

目的分析膈肌包埋法救治重度肝破裂出血的临床护理特点。方法回顾性分析2000年1月~2011年5月因重度肝破裂行膈肌包埋法治疗的15例患者临床资料。结果经积极治疗和精心护理治愈12例(80.0%),死亡3例(20.0%);治愈12例中均有不同程度的术后并发症,术后非手术处理均痊愈。结论膈肌包埋法是紧急情况下救治重度肝破裂的一种简单、有效的治疗方法,针对其护理特点,采取相应护理策略是患者恢复的重要保证。     

带蒂膈肌瓣重建食管的临床解剖学可行性研究

目的　为带血管蒂膈肌瓣重建食管提供解剖学依据。 方法　在12具经动脉灌注红色乳胶的成人防腐标本上, 解剖观测膈肌神经血管的起源、走行、外径、分布、长度及其交通情况。 结果　膈肌的营养血管主要有膈下动脉,肌膈动脉、心包膈动脉膈肌支、膈上动脉和下位肋间后动脉的部分分支。膈下动脉是膈肌的主要供血血管,主要起始于腹腔动脉干或腹主动脉,起始点外径分别为：（1.52±0.06）mm,（1.61±0.04）mm。经左右膈脚的两侧上行进入膈肌,分别分成前、后两支。前支行向前外,支配中心腱中间部、中心腱两侧叶前部、部分膈肌前肋部,后支行向后外,分布中心腱两侧叶后部、部分膈肌后肋部、部分膈肌腰部。 结论　以膈下动脉为血管蒂的膈肌瓣完全具有重建食管的解剖学可行性。