Covered metal stent for tumor obstruction of efferent loop recurrence after gastrectomy

Reports the case of a 60-year-old woman who underwent R2 total gastrectomy, and subsequent palliation of painful symptom recurrence via a membrane-covered metal stent. Received: 13 June 1996/Accepted: 31 July 1996     

Selective degeneration of CA1 pyramidal cells by chronic application of bismuth

The heavy metal bismuth induces a new type of selective neuronal degeneration that shares some common aspects with that seen following hypoxia and ischemia. Continuous application of 3 μm bismuth to organotypic cultures of rat hippocampus resulted after 2–3 weeks in selective degeneration of CA1 pyramidal cells, while CA3 pyramidal cells, dentate granule cells, and subicular neurons were resistant. With 10 μm MK-801, a noncompetitive NMDA-antagonist, during the entire culturing period failed to prevent neuronal degeneration induced by 3 μm bismuth. GABA-immunoreactive interneurons were also affected by bismuth, but were generally less sensitive than CA1 pyramidal cells. Acute application of up to 100 μm bismuth did not change the electrophysiological properties of CA1 pyramidal cells. © 1994 Wiley-Liss, Inc.     

鸡蛋清中卵转铁蛋白的分离提取

采用固定化金属螯合亲和色谱法(IMAC),从蛋清中分离和提取卵转铁蛋白(OVT).结果表明,采用均质处理蛋清液并结合硅藻土过滤澄清的预处理方法,去除了蛋清中的粘蛋白等一些影响柱分离的杂质蛋白,减轻了色谱柱的污染,延长了柱的使用寿命,从而降低了生产成本.SDS-PAGE电泳分析显示,分离提取的OVT纯度达到96%,远高于商品OVT;电喷雾质谱分析显示,OVT的相对分子质量为76 500.     

Cobalt-dependent potentiation of net inward current density in Helix aspersa neurons.

A low concentration of transition metal ions Co2+ and Ni2+ increases the inward current density in neurons from the land snail Helix aspersa. The currents were measured using a single electrode voltage-clamp/internal perfusion method under conditions in which the external Na+ was replaced by Tris+, the predominant external current carrying cation was Ca2+, and the internal perfusate contained 120 mM Cs+/0 K+; 30 mM tetraethylammonium (TEA) was added externally to block K+ current. In the presence of Co2+ (3 mM) or Ni2+ (0.5 mM) inward Ca2+ currents were stimulated normally by voltage-dependent activation of Ca2+ channels. There was a 5-10% decrease in the rate of rise of the inward current. The principal effect of Co2+ and Ni2+ in increasing the current density seems to be a decrease in the rate at which the inward currents decline during a depolarizing voltage pulse. The results may be due to a decrease in a voltage-dependent or Ca(2+)-dependent outward current and/or an inhibition of Ca2+ channel inactivation. Outward current under these conditions (zero internal K+) was significant and most likely due to Cs+ efflux through the voltage-activated or Ca(2+)-activated nonspecific cation channels. Co2+ is an extremely effective blocker of this outward current. These results are not an artifact of internal perfusion or the special ionic conditions. Intracellular recording of unperfused neurons in normal Helix Ringer's solution showed that the Ca(2+)-dependent action potential duration was increased significantly by low concentrations of Co2+. This result is consistant with the Co(2+)-dependent increase in inward (depolarizing) current seen in voltage-clamp experiments.     

金属基底上聚合吡咯的电化学及电镜表征

用循环伏安法研究了吡咯在不同金属基底不同支持电解质中的聚合过程，对不同基底上制备的聚吡咯膜进行了电化学、扫描电镜、表面能谱等方面的研究，考察了聚吡咯膜电极对ＮＯ_３－离子的电位响应情况，结果表明，不同基底不同支持电解质在不同的吡咯浓度中表现出各异的伏安行为，经电化学处理的聚吡咯膜电极均对ＮＯ_３－呈Ｎｅｒｎｓｔ响应，扫描电镜观察表明除Ｐｔ基底外在其它基底上制备的聚吡咯膜均呈颗粒性球状堆集。     

Laparoscopic Deployment of Biliary Self-Expandable Metal Stent (SEMS) for One-Step Palliation in 23 Patients with Advanced Pancreatico-Biliary Tumors—a Pilot Trial

Background Exploratory laparoscopy is commonly undertaken in patients with highly suspicious biliary and pancreatic lesions to facilitate diagnosis and staging cancer is present. If an unresectable tumor is identified, a second endoscopic procedure may be required do deploy a self-expandable metal stent (SEMS) for palliation. As endoscopic retrograde cholangio pancreatography (ERCP) may be unsuccessful in up to 20% of patients, we evaluated the feasibility and safety of deployment of self-expandable metal stents at the same time as the initial laparoscopy. Patients and Methods A total of 23 eligible patients (8 male and 15 female) with malignant obstruction of the common bile duct underwent deployment of SEMS at laparoscopy. Primary outcome measure was the successful laparoscopic deployment of stent and secondary outcome measure was complications rates. Results Indications for stent deployment were unresectable pancreatic cancer in 18, cholangiocarcinoma in two, neuroendocrine tumor in one and ampullary adenocarcinoma in two patients. The median age was 73 years (range 49–93). Twenty-two of 23 stents were deployed successfully: 17 stents were deployed transcystically and five via a choledochotomy. Median times for laparoscopic exploration and SEMS deployment were 165 min (range 105–230) and 20 min (range 10–50), respectively. Pre- and post-procedures median total bilirubin were 9.4 mg/dl (range 5.4–17.5) and 4.0 (range 2.6–7.1). The median size of the pancreatic mass was 3 cm (range 2–5 cm) and that of the common bile duct (CBD) from 9.2 mm (range 7.2–17.4). The mean duration of laparoscopy was 170 min (range 120–230 min) and that for stent deployment 23 min (range 10–50 min). Complications included bleeding, obstruction, and wound infection. Bleeding occurred on day 7 in two patients and on day 30 in one patient; bleeding occurred at the gastrojejunal anastomosis site and was successfully treated with endoscopic hemostasis. A total of three stent obstructions were identified: one each at 60, 90, and 120 days follow-up. All complications were successfully managed endoscopically. There were a total of seven deaths, six as a result of progressive cancer and one of surgical wound infection and ensuing complications. Conclusion This study demonstrates that laparoscopic deployment of self-expandable metal bile duct stents is feasible and safe. This option appears to be a reasonable option in patients with inoperable malignant obstruction of the distal common bile duct.     

Spiral-shaped Metallic Implant in the Treatment of Achilles Tendon Ruptures: An Experimental Study on the Achilles Tendon of Sheep

There are 2 main factors contributing to the strength of tendon repair: the tensile strength of the material used in repair and the tendon-holding capacity of the suture configuration. In the current study, we aimed to find a technique with high repair strength by increasing both the tensile strength of the material and the tendon-holding capacity of the configuration. We developed metal implants (models 1 and 2) made from stainless-steel wire with 2 different spiral-shaped configurations. We measured tendon-holding capacities of these alternative implants biomechanically and compared them with frequently used suture techniques, the Bunnell and locking loop, which were achieved with 5 Ticron sutures. Sixty-four sheep Achilles' tendons were used in the study as 16 tendons in each group. Model 2 was more resistant to deformation under loading when compared with model 1. The results demonstrated that model 2 was superior to model 1 and both suture techniques. This study could be accepted as a step for reaching a strong tendon repair technique. It should be emphasized that the technique needs to be improved technically to make it convenient for clinical use.     

Pancreaticoduodenectomy after placement of endobiliary metal stents

Contemporary treatment programs for patients with potentially resectable pancreatic cancer often involve preoperative therapy. When the duration of preoperative therapy exceeds 2 months, the risk of plastic endobiliary stent occlusion increases. Metal stents have much better patency but may complicate subsequent pancreaticoduodenectomy (PD). We evaluated rates of perioperative morbidity, mortality, and stent complications in 272 consecutive patients who underwent PD at our institution from May 2001 to November 2004. Of these 272 patients, 29 (11%) underwent PD after placement of a metal stent, 141 underwent PD after placement of a plastic stent, 10 had PD after biliary bypass without stenting, and 92 had PD without any form of biliary decompression. No differences were found between the Metal Stent group and all other patients in median operative time, intraoperative blood loss, or length of hospital stay. No perioperative deaths occurred in the Metal Stent group versus 3 (1.2%) deaths in the other 243 patients. The incidence of major perioperative complications was similar between the two groups, including the rates of pancreatic fistula, intra-abdominal abscess, and wound infection. Furthermore, there were no differences in the perioperative morbidity or mortality rates between patients who underwent preoperative biliary decompression with a stent of any kind (metal or plastic) and those patients who underwent no biliary decompression at all. Metal stent-related complications occurred in 2 (7%) of 29 patients during a median preoperative interval of 4.1 months; in contrast, 75 (45%) of the 166 patients who had had plastic stents experienced complications, including 98 stent occlusions, during a median preoperative interval of 3.9 months (P < 0.001). We conclude that the use of expandable metal stents does not increase PD-associated perioperative morbidity or mortality, and as such an expandable metal stent is our preferred method of biliary decompression in patients with symptomatic malignant distal bile duct obstruction in whom surgery is not anticipated, or in whom there is a significant delay in the time to surgery. Presented at the Forty-Sixth Annual Meeting of The Society for Surgery of the Alimentary Tract, Chicago, Illinois, May 14–18, 2005 (oral presentation). Supported by the Lockton Fund for Pancreatic Cancer Research, The University of Texas M. D. Anderson Cancer Center, Houston, Texas.     

锤造全冠的适合性实验研究（三种缩颈方法的比较）

用实验方法比较三种常用的缩颈方法及评价锤造全冠的边缘适合性。结果表明各组边缘间隙均大于０．１８０ｍｍ，说明锤造全冠边缘适合性较差，临床检查难以确定其间隙大小。各组近胎面轴壁间隙较小，这与冠成形时此处受力较大，冠周径变小有关，提示临氏上应避免用力和反复锤击此处。各组胎面间隙均大于０．１３０ｍｍ，表明面升高，边缘浮出量较大，冠尚未完全就位。当硬铅代型与缩颈器之间未预留冠套间隙时，所得的锤造全冠适合性更差，面间隙最大（０．９４５ｍｍ）。     

用酸蚀法提高纯钛与光固化冠桥树脂粘结强度的研究

目的：研究用酸蚀法提高钛与光固化复合树脂剪切粘结强度的可行性，并观察表面粗糙度与剪切粘结强度之间的关系。方法：采用不同浓度的酸蚀剂对钛铸件表面进行酸蚀，并与artglass光固化复合树脂进行粘结，以单纯喷砂组为对照，比较剪切粘结强度的差异。对酸蚀后及剪切试验后的金属表面进行扫描电镜观察，并测定其表面粗糙度。结果：用酸蚀法可以显著提高钛与复合树脂的粘结强度，HF浓度为4％时粘结强度最高。表面粗糙度随酸蚀剂的浓度增高而下降。结论：纯钛铸件用酸蚀法处理后可以获得较高的粘结强度，HF酸浓度以4％为宜。表面粗糙度对粘结强度不起决定性作用。