The nucleotide excision repair epistasis group in Neurospora crassa

Summary DNA repair mutants in eucaryotes are normally assigned to three epistasis groups. Each epistasis group represents a pathway for DNA repair. The pathways are commonly designated (1) nucleotide excision repair, (2) recombination repair and (3) mutagenic repair. An excision repair epistasis group has been established in Neurospora and the mutants assigned to this group should be limited in their ability to excise pyrimidine dimers and other bulky lesions from DNA. Using a pyrimidine dimer-specific assay, we have found that all Neurospora crassa mutants assigned to the excision repair epistasis group are capable of removing pyrimidine dimers from the DNA at a rate similar to the wild-type organism.     

A role for genomic instability in cellular radioresistance?

Summary Inherent cellular radioresistance plays a critical role in the failure of radiotherapy. Although the consequences of radioresistance are well known, the molecular, biological, and cellular bases of radioresistance remain a mystery. We propose that genomic instability, the increased rate of acquisition of alterations in the mammalian genome, can directly modulate cells' sensitivity to radiation. In particular, destabilization of chromosomes occurring as a consequence of genomic instability may result in enhanced plasticity of the genome. This increased plasticity of the genome allows cells to better adapt to changes in local environment(s) during tumor progression, or improve cell survival following exposure to DNA damage encountered during radiotherapy protocols, thereby contributing to radioresistant cell populations found in tumors both before and after radiotherapy.     

胫后侧逆行岛状筋膜蒂皮瓣修复踝周围软组织缺损

总结１９９３年５月－１９９８年８月,应用胫后侧二种逆行岛状筋膜蒂皮瓣多向转位修复踝部周围皮肤缺损的临床效果。利用胫后动脉肌间隙的穿动脉,腓动脉肌间隙支,腓动脉外踝支与腓肠浅动脉广泛吻合,设计胫后侧两种筋膜蒂皮瓣。     

Endoscopic vs conventional hernia repair from an immunologic point of view

Background: In this study we tried to estimate the local surgical trauma in patients undergoing endoscopic or conventional hernia repair via the changes in peripheral blood T cell subpopulations (i.e., T-helper 1 (TH1) and TH2 cells), recently shown to be recruited differentially to inflammatory sites. Methods: Cells were identified flow-cytometrically by intracellular cytokine staining on a single cell level in 30 patients undergoing conventional (Shouldice) or total extraperitoneal patch (TEPP) hernia repair. Results: The TH1 cells decreased postoperatively in Shouldice patients on an average of 20.8–31.4%, whereas in TEPP patients only a minor decline (mean, 7.8–9.2%) was observed. The TH2 cells did not change significantly in TEPP patients, and a small increase (mean, 7.7%) was detected in Shouldice patients. Conclusions: Our results suggest that the postoperative reduction in TH1 cells reflects local surgical trauma and can be helpful in evaluating different surgical procedures. When conventional and endoscopic hernia repair were compared, the latter proved less traumatizing. Received: 18 March 1998/Accepted: 24 July 1998     

A simplified laparoscopic technique for mesh placement in ventral hernia repair

The use of a large synthetic mesh for laparoscopic repair of significant ventral abdominal wall defects may be accompanied by technical difficulties resulting from improper orientation and positioning of the mesh over the defect. We suggest a technique based on initial fixation of the mesh center to the central point of the defect, and subsequent centrifugal attachment of the mesh to the abdominal wall. This technique is advantageous because it leads to precise orientation and positioning of the synthetic patch and to significant reduction of the time needed for its reinforcement over and around the defect. Received: 25 September 1998/Accepted: 27 November 1998     

Spatiotemporal progress of nerve regeneration in a tendon autograft used for bridging a peripheral nerve defect

We have previously shown that a tendon autograft from the rat tail can support regeneration across a gap in the continuity of the rat sciatic nerve. In this study, we characterized the spatiotemporal progress of regeneration in such a graft bridging a 10-mm defect in the sciatic nerve of the rat. Regeneration was assessed 7, 10, 14, or 18 days postoperatively, by immunocytochemistry for axons, Schwann cells, and macrophages and histochemistry for blood vessels. Axonal regrowth into the grafts showed an initial delay period of 6.8 days, whereafter axons grew at a rate of 1.0 mm/day. Schwann cells grew into the grafts from both the proximal and distal nerve segments, proximally just ahead of the axonal front. Macrophages were initially preferentially located at the periphery of the grafts, but gradually increased inside the grafts. Blood vessels entered the grafts from both the proximal and distal aspects of the severed nerve. The onset of vascularization appeared to coincide with axonal regeneration into the grafts.     

严重颅眶损伤的特点和救治

目的探讨严重颅眶损伤的特点和救治。方法回顾分析1990年1月～1997年12月收治的32例严重颅眶损伤患者的临床资料。结果32例严重颅眶损伤的临床特点为：脑损伤局限．意识障碍较轻,嗅神经、视审经损伤多见,脑脊液漏发生率高,颅眶畸形严重。结论应重视院前急救,尽早转送专科医院．除清除颅内血肿外,应注重视神经损伤、脑脊液漏和颅眶畸形手术处理．积极治疗并发症,有利于视神经功能的恢复,并能有效预防脑脊液漏引起的颅内感染．改善面部外观。     

Retropublic colpourethropexy with transabdominal anterior and/or posterior repair for the treatment of genuine stress urinary incontinence and genital prolapse

A new operative technique combining retropublic colpourethropexy with transabdominal internal anterior and/or internal posterior repair for the treatment of genuine stress incontinence (GSI) and genital prolapse is described in 75 cases. The overall success rate in correcting GSI was 92.0%, with a 94.8% success rate in the primary surgical group (n=58) and an 82.4% in the secondary group (n=17). Average follow-up has been 1.31 years (range 6 weeks–6 years). There was a 3.4% incidence of residual prolapse. Nine patients also underwent concomitant colpourethropexy. Overall surgical complications include febrile morbidity 4/75 (5.3%), wound infection 1/75 (1.3%), deep vein thrombosis 1/75 (1.3%) and partial ureteric obstruction 1/75 (1.3%). There were no statistically significant changes in multichannel urodynamic studies preoperatively and at 1 year following surgery. Onethird (2/6) of the GSI failures had low MUCP (<20 cm H₂O) prior to surgery and continued so at 1 year follow-up.EDITORIAL COMMENT: Genital prolapse is often present in patients who have GSI. If an operation is performed to correct the GSI, and those areas of weakness in the pelvic support system that are contributing to the genital prolapse are not treated, the genital prolapse will become more severe. In the operation which has been described, the colpopexy sutures will correct any cystourethrocele, and the removal of the wedge of tissue from the anterior superior vaginal wall will correct the cystocele. The removal of the wedge of tissue from the posterior superior vaginal wall will reduce the redundancy of the posterior vaginal fornix, but a culdeplasty of the Moschcowitz or Halban type is recommended to treat or prevent an enterocele and to place the vaginal apex in the hollow of the sacrum. Any coexistent rectocele must always be treated vaginally. If it is not treated, it will appear to be more advanced following elevation of the anterior vaginal wall by retropubic urethropexy and the anterior repair which has been recommended.Genital prolapse is best treated by a vaginal approach. When one must une an abdominal approach, ancillary procedures such as the authors have described should be considered. A bulbous upper vagina is ideal for childbearing but if the apical support system and vaginal wall is weakened it is predisposed to prolapse. If the surgeon, in operating for genital prolapse, which involves the upper vagina, will taper the vaginal apex and support it by obliteration of the cul-desac and shortening and reattachment of the uterosacralcardinal complex, postoperative prolapse will be less likely to recur.     

Posterior Laryngeal Clefts: Preliminary Report of a New Surgical Procedure Using Tibial Periosteum As an Interposition Graft

Objective: To present the preliminary results of a new surgical procedure for posterior laryngeal cleft repair. Design: Retrospective study in an academic tertiary care center. Method: The study included three male patients (age at surgery, 2, 13, and 14 mo). One presented with severe aspiration and cyanotic attacks, the two others with aspiration and recurrent chest infections. The types of laryngeal clefts included complete cleft of the cricoid with varying degrees of tracheal involvement but not further than the first six tracheal rings. Associated malformations included one VATER syndrome, one esophageal atresia, and one tracheoesophageal fistula. Surgery was performed under general anesthesia with nasotracheaI intubation. A vertical anterior laryngofissure was performed. The mucosal margins of the clefts were incised and then repaired in two layers with polyglactin sutures. The original feature of this procedure was the interposition of a small piece of tibial periosteum between the two layers. This fascia graft is known to be strong and resistant in cleft palate surgery. Main Outcome Measure: Clinical and endoscopic follow-up was used for evaluation of results. Results: The three patients had successful laryngeal repair at a mean follow-up of 6 months (range, 4-14 mo). Conclusion: The anterior laryngofissure provides a good surgical access to the cleft. The interposition of tibial periosteum allows durability of the cleft repair. A longer follow-up is needed to confirm these preliminary results. A computed tomography scan study and a study on the rabbit are planned in order to evaluate the outcome of these periosteal grafts.