脉冲电磁场影响人骨髓基质干细胞缝隙连接通讯的实验研究

目的研究脉冲电磁场(PEMFs)对人骨髓基质干细胞(hBMSCs)缝隙连接所介导细胞间通讯(GJIC)的影响。方法透射电镜观察BMSCs超微结构,应用荧光漂白恢复(FRAP)技术,通过激光共聚焦显微镜检测hBM-SCs经PEMFs刺激后GJIC的功能变化。结果经PEMFs刺激后的hBMSCs,平均荧光漂白恢复率为(64.12±0.83)%,较对照组犤(35.26±0.76)%犦有显著性增加(P<0.05)。结论PEMFs刺激能促进hBMSCs的缝隙连接通讯功能。     

Type classification of anomalous pancreaticobiliary junction by ERCP

The role of endoscopic retrograde cholangiopancreatography (ERCP) in the preoperative assessment of anomalous pancreaticobiliary junction was retrospectively evaluated in 74 consecutive patients (19 males and 55 females; aged 0–80 years). Sixty-three patients had congenital biliary dilatation and 11 did not. Type classification of congenital biliary dilatation was possible by ERCP alone in 45 patients (71%). The main causes of classification failure were previous bilio-enteric anastomosis and restriction of postural changes during ERCP due to general anesthesia in pediatric patients. Classification of anomalous junction was possible in 69 patients (93%). Technical difficulty in ERCP caused classification failure in 5 patients. Neoplastic lesions were found in 12 patients (16%) and all but 1 were correctly diagnosed by ERCP. We conclude that ERCP plays an important role in the preoperative diagnosis and type classification of anomalous pancreaticobiliary junction and congenital biliary dilatation.     

Accessory Scrotum with Penoscrotal Transposition and Retrocerebellar Arachnoid Cyst: A Case Report

A 2-year-old boy presented with an accessory scrotum associated with penoscrotal transposition and a perineal lipoma. He also had a retrocerebellar arachnoid cyst. The accessory scrotum was resected with concurrent scrotoplasty. The retrocerebellar arachnoid cyst was seen on a subsequent brain computed tomography scan and was left untreated because there was no evidence that the volume was increasing.     

Anin vitro electrophysiological study of the colon from patients with idiopathic chronic constipation

Preparations of the circular muscle layer from the sigmoid colon resected from patients with idiopathic chronic constipation were compared, at an electrophysiological level using the sucrose-gap technique, with preparations of the same region of the intestine resected from patients with rectal carcinoma. Non-adrenergic, non-cholinergic inhibitory neuromuscular transmission, represented by inhibitory junction potentials, was present in preparations from both groups. However, the inhibitory response in preparations from constipated patients had a slower or longer time-course than in those from cancer patients. Also, rebound activity following inhibitory transmission was observed in 34% of preparations from constipated patients but was observed in 67% of preparations from cancer patients. Preparations from both groups displayed the same patterns of spontaneous activity and the same proportion of each group was quiescent. The threshold for generation of action potentials and the passive resistance of the smooth muscle membrane were the same in both groups. However, quiescent preparations from constipated patients were less likely to discharge trains of action potentials when the smooth muscle membrane was depolarized than were preparations from cancer patients. These changes in transmission processes and excitability in tissue from constipated patients are discussed in relation to altered states of colonic motility found in people with idiopathic chronic constipation.     

VESICO-URETERIC REFLUX AND SURGICALLY TREATED PELVI-URETERIC JUNCTION OBSTRUCTION IN INFANTS UNDER THE AGE OF 12 MONTHS

Background : Pelvi-ureteric junction obstruction has been increasingly diagnosed in infants, mostly as a consequence of antenatal ultrasound examinations. Methods : Of 55 infants below the age of 12 months who underwent dismembered pyeloplasty over a 7-year period, we aimed to determine the patterns and outcome of associated vesico-ureteric reflux that was present in 15 (28%) of the 53 infants in whom follow-up was available. Results : A total of eight infants had resolution of their reflux with conservative management and the median time to resolution was 15 months. Five infants proceeded to ureteroneocystotomy. Conclusions : Given the association of vesico-ureteric reflux and pelvi-ureteric junction obstruction, routine cystography is recommended when the diagnosis of pelvi-ureteric junction obstruction is made.     

Niflumic acid-induced increase in potassium currents in frog motor nerve terminals: effects on transmitter release

The actions of the nonsteroidal antiinflammatory drug niflumic acid were studied on frog neuromuscular preparations by conventional electrophysiological techniques. Niflumic acid reduced the amplitude and increased the latency of endplate potentials in a concentration-dependent manner. Neuromuscular junctions pretreated with niflumic acid (0.05–0.5 mM) showed much less depression than control when they were stimulated with trains of impulses. Inhibition of acetylcholine release was reverted by raising the extracellular Ca²⁺ concentration but not by simply washing out the preparations with niflumic acid-free solutions. Pretreatment with indomethacin (0.1 mM), another nonsteroidal antiinflamatory drug, did not affect the niflumic acid-induced inhibition of evoked responses. Niflumic acid (0.1 mM) did not change the amplitude of miniature endplate potentials and had a dual action on the frequency of miniatures: it decreased their frequency at 0.1 mM whereas it produced an enormous increase in the rate of spontaneous discharge at 0.5 mM. Niflumic acid (0.1–1 mM) reversibly increased the amplitude and affected the kinetics of presynaptic voltage-activated K⁺ current and Ca²⁺-activated K⁺ current in a concentration-dependent manner. Niflumic acid (0.1–1 mM) irreversibly decreased the amplitude and reversibly affected the kinetics of the nodal Na⁺ current. Indomethacin (0.1 mM) had no effect on presynaptic currents. In conclusion, niflumic acid reduces acetylcholine release by increasing presynaptic K⁺ currents. This may shorten the depolarizing phase of the presynaptic action potential and may reduce the entry of Ca²⁺ with each impulse.     

Effect of β-endorphin on the contractile responses in mouse skeletal muscle

Tension development in response to direct and indirect electrical stimulation was studied in an isolated phrenic nerve hemidiaphragm preparation of the mouse. β-Endorphin (β-EP) caused an increase in the preparation of the mouse. β-Endorphin (β-EP) caused an increase in the response to low frequency stimulation of the nerve. Upon direct stimulation of the muscle the peptide had no effect. The actions of β-EP were abolished in the presence of the opioid antagonist naloxone and mimicked by β opioid agonists. Upon high frequency stimulation of the nerve, β-EP caused an increase in the initial, maximum, and mean tension. It also prevented the fall in the final tension seen in the control preparations with repeated periods of stimulation. The findings are consistent with β-EP having a role to improve neuromuscular function and deley fatigue, and indicate the possible therapeutic potential of opioid substances in conditions where muscle weakness is present. © John Wiley & Sons, Inc.     

Pulsing electromagnetic field stimulation of the in vitro growth plate

Specific pulsing electromagnetic fields (PEMFs) have been used to stimulate growth and repair of osteogenic tissues; however, the basis for this specificity is unknown. Previously, we determined the relevant electromagnetic field parameters of the clinically used PEMF and independently verified the beneficial effects of PEMFs on the rabbit fibula fracture healing model. The goal of the present study was to develop an in vitro model that would permit the effectiveness of various electric and magnetic field components of the PEMF to be determined. The costochondral junction (CCJ) of the 21-day-old rat was exposed in vitro to PEMFs with various electric and magnetic field component amplitudes. Response of this model to PEMFs was determined by nondestructive macrophotographic measurement of CCJ growth. Preliminary data indicated that temperature effects were present in this in vitro system. Subsequent experiments designed to separate the effects of temperature and PEMFs on the growth of CCJs in tissue culture were performed. Results indicate that accurate and frequent temperature measurements must be made for in vitro models being used to study effects of PEMFs. Small temperature differences induced by the coils used to produce PEMFs in the CCJ experimental system can have significant stimulatory effects, and the combined effects of temperature and PEMFs are not linearly additive in this model. Furthermore, our results suggest that thermal and PEMF stimuli could affect macrophotographically measured growth of the CCJ by separate mechanisms or could have a synergistic effect. Therefore, PEMF stimulation experiments should be performed under strictly "athermal" conditions.     

血管内皮细胞条件培养基促进胃癌细胞增殖和迁移

探讨血管内皮细胞培养基对胃癌细胞增殖和迁移的影响,分析血管内皮细胞调控胃癌细胞发生转移的机制。方法 设置对照组和共培养组,分别将正常培养基和人脐静脉血管内皮细胞HUVEC条件培养基作用于胃癌细胞HGC27,采用MTT法和划痕试验检测胃癌细胞HGC27的增殖活性和迁移能力。设置Control组、6 h组、12 h组和24 h组,以HUVEC的条件培养基作用于胃癌细胞6、12和24 h,Western blot检测EMT标志物和紧密连接蛋白的表达变化,激光共聚焦显微镜观察细胞骨架和紧密连接蛋白的分布变化。结果 MTT及划痕试验表明HUVEC条件培养基促进胃癌细胞HGC27的增殖和迁移。与Control组比较,间接共培养后胃癌细胞的形态呈间充质状改变,丝状伪足样凸起数量显著增加。 Western blot结果显示间接共培养后胃癌细胞上皮标志物E-cadherin表达水平逐渐下降,而间充质标志物N-cadherin和MMP-9逐渐增加,具有时序性变化规律。ZO-1和Occludin的表达也逐渐下降,细胞膜分布减少。结论 间接共培养下,血管内皮细胞通过上调胃癌细胞MMP-9,破坏紧密连接,促进胃癌细胞增殖和迁移