Nav1.1 channels with mutations of severe myoclonic epilepsy in infancy display attenuated currents

Severe myoclonic epilepsy in infancy (SMEI) is characterized by intractable febrile and afebrile seizures, severe mental decline, and onset during the first year of life. Nonsense, frameshift, and missense mutations of SCN1A gene encoding the voltage-gated Na(+) channel alpha-subunit type I (Na(v)1.1) have been identified in patients with SMEI. Here, we performed whole-cell patch-clamp analyses on HEK293 cells expressing human Na(v)1.1 channels bearing SMEI nonsense and missense mutations. The mutant channels showed remarkably attenuated or barely detectable inward sodium currents. Our findings indicate that SMEI mutations lead to loss-of-function and may contribute to the development of SMEI phenotypes.     

吡咯野百合碱对培养的牛肺动脉内皮细胞NO、细胞内钙及胶原凝胶收缩的影响

目的通过吡咯野百合碱(monocrotaline pyrrole,MCTP)对牛肺动脉内皮细胞(calf pulmonary artery endothelial cells,CPAE)NO、细胞内钙和胶原凝胶收缩的影响,探讨MCTP导致肺动脉高压的机理.方法采用fura-2测定细胞NO及细胞内钙的含量;采用胶原凝胶收缩实验分析CPAE的功能.结果MCTP减少ACh所致NO及细胞内钙增加的作用,分别从(6.1±1.3)%减少到(1.5±1.1)%和从(70.2±3.2)nmol·L-1减少到(26.8±5.3)nmol·L-1.MCTP还可抑制ACh所致的胶原凝胶舒张,从(101.3±0.68)%减少到(94.1±0.77)%.结论MCTP可通过抑制CPAE的NO生成,影响肺动脉平滑肌的舒缩,可能是其导致肺动脉高压的一个因素.     

Quantitative analysis of toxin extracts from various tissues of wild and cultured puffer fish by an electrophysiological method.

We observed the effects of the toxin extracted from various tissues of wild and cultured puffer fish on voltage-dependent sodium current (I(Na)) using single rat CA1 neurons, and compared the results with that of tetrodotoxin (TTX). Toxin extracts from wild puffer fish inhibited I(Na) in a dilution-dependent manner, and toxin extracts from liver or ovary produced 300 times greater inhibition than that from muscle, and corresponded to about 65 microg TTX/g tissue. We also used puffer fish cultured in net cages or in tanks set up on land, in an attempt to isolate them from the food chain. The toxin extracts from cultured puffer fish also suppressed I(Na), but the inhibition was much weaker, and the effects of toxin extracts were almost the same in all tissues examined including liver, ovary, muscle, etc. We calculated the maximum edible amount for each tissue, assuming that the lethal dose of TTX is 1-10 microg/kg, and we found that the liver or ovary was edible in the case of cultured puffer fish.     

Magnetic resonance imaging of hydrostatic pulmonary edema in isolated dog lungs: comparison with computed tomography

Magnetic resonance imaging (MRI) is considered inferior to computed tomography (CT) in the assessment of lung parenchyma, being hampered by low proton density, magnetic susceptibility effects, flow, and cardiac and respiratory motion. In this study the authors assessed the potential usefulness of MRI by comparing it with corresponding CT images of the lung in the absence of motion. They studied eight excised normal canine lung lobes inflated with oxygen before and after induction of pulmonary edema produced by intravascular infusion of saline at 30 cm H2O. T1, T2 and proton density weighted, 5-mm thick, gapped, multislice sequences were performed at 1.5 T. Magnetic resonance images were compared with corresponding 5-mm collimation CT scans at identical levels both before and after the induction of pulmonary edema. The MR and CT scans were assessed independently by two chest radiologists. In normal lung, there was equivalent visualization of vessels down to 1 mm and bronchi to 2 mm in diameter. T1 and proton density scans demonstrated lower spatial resolution but greater contrast than the corresponding CT images. In pulmonary edema both T1 and proton density sequences demonstrated peribronchial edema with greater contrast than CT. Air-space filling was equally well demonstrated by either technique. The authors conclude that, in motionless lung, MRI has lower spatial but greater contrast resolution than CT. It is potentially superior to CT in assessing focal and diffuse lung disease if cardiac and respiratory motion artifacts can be minimized or suppressed.     

A case of using the remnant stomach as substitute after esophagectomy for esophageal cancer with history of distal gastrectomy

A 63-year-old man who had a distal subtotal gastrectomy and retrocolic end-to-side gastrojejunostomy was admitted because of a mid-thoracic esophageal cancer. He underwent a two-stage subtotal esophagectomy and reconstruction using the remnant stomach without microvascular anastomosis. We preserved the splenic artery, splenic vein, and the short gastric artery. The remnant stomach was pulled up together with the pancreas through the anterior sternal route. The superiority of this technique is that microvascular anastomosis is not needed because a sufficient blood supply from the splenic artery and only two anastomoses are needed, compared with three or four anastomoses when using the colon. This technique is also likely to be safer for patients requiring an esophagectomy after a distal gastrectomy.     

Laparoscopic rectal surgery for middle and lower rectal cancer

Background  

The usefulness of laparoscopic low anterior resection for middle and lower rectal cancer remains controversial.