Effect of gap size on gliding resistance after flexor tendon repair

BACKGROUND: Gap formation is a common complication after flexor tendon repair and is associated with adhesion formation, tendon rupture, and decreased strength. The purpose of this study was to investigate the effect of gap formation on tendon gliding resistance after flexor tendon repair in a human cadaver model. METHODS: Twelve index, middle, and ring fingers from four adult human cadaveric hands were used. Gliding resistance versus excursion between the flexor digitorum profundus tendon and the A2 pulley was first measured in intact tendons. After full laceration, each tendon was repaired with the Pennington suture technique and the gliding resistance was measured again. Then, the repaired tendon (a 0-mm gap) was stretched to form a 1-mm gap, and gliding resistance was remeasured. A magnified video image was used to monitor gap size. This process was repeated to evaluate gap sizes of 2, 3, and 4 mm at the repair site. Peak gliding resistance was determined, and the peak gliding resistance was compared among the groups. RESULTS: No significant difference in peak gliding resistance was detected between repaired tendons without a gap and tendons with a 1-mm gap. Repaired tendons with a 2-mm gap could pass through the A2 pulley; however, peak gliding resistance was significantly higher than that for tendons with a 0 or a 1-mm gap (p < 0.05). When the gap reached > or =3 mm, all tendons caught at the A2 pulley edge, causing a dramatically increased peak gliding resistance. CONCLUSIONS: The presence of a 2-mm gap after flexor tendon repair significantly increased tendon peak gliding resistance (p < 0.05), while a gap of > or =3 mm further increased peak gliding resistance because of catching at the pulley edge.     

Detrimental effects of overstuffing or understuffing with a radial head replacement in the medial collateral-ligament deficient elbow

BACKGROUND: Comminuted radial head fractures associated with an injury of the medial collateral ligament can be treated with a radial head implant. We hypothesized that lengthening and shortening of the radial neck would alter the kinematics and the pressure through the radiocapitellar joint in the medial collateral ligament-deficient elbow. METHODS: The effects of lengthening (2.5 and 5 mm) and shortening (2.5 and 5 mm) of the radial neck were assessed in six human cadaveric upper extremities in which the medial collateral ligament had been surgically released. The three-dimensional spatial orientation of the ulna was recorded during simulated active motion from extension to flexion. Total varus-valgus laxity and ulnar rotation were measured. Radiocapitellar joint pressure was assessed with use of pressure-sensitive film. RESULTS: Radial neck lengthening or shortening of >/=2.5 mm significantly changed the kinematics in the medial collateral ligament-deficient elbow. Lengthening caused a significant decrease (p < 0.05) in varus-valgus laxity and ulnar rotation (p < 0.05), with the ulna tracking in varus and external rotation. Shortening caused a significant increase in varus-valgus laxity (p < 0.05) and ulnar rotation (p < 0.05), with the ulna tracking in valgus and internal rotation. The pressure on the radiocapitellar joint was significantly increased after 2.5 mm of lengthening. CONCLUSIONS: This study suggests that accurate restoration of radial length is important and that axial understuffing or overstuffing of the radiohumeral joint by >/=2.5 mm alters both elbow kinematics and radiocapitellar pressure. CLINICAL RELEVANCE: This in vitro cadaver study indicates that a radial head replacement should be performed with the same level of concern for accuracy and reproducibility of component position and orientation as is appropriate with any other prosthesis.     

蛋白质酵母双杂交系统的建立及其在大肠癌肝转移研究中的意义

目的 建立酵母双杂交系统,筛选与FasL相互作用的蛋白,探讨FasL与大肠癌肝转移的关系。方法 以FasL基因构建诱饵蛋白质粒,筛选人胎肝cDNA文库,鉴定与FasL相互作用的蛋白,通过生物信息学分析FasL及其相互作用蛋白在大肠癌肝转移中的作用。结果 筛选出10个与FasL特异性相互作用的蛋白,包括金属硫蛋白1K、1G、2A,组织蛋白酶B,脂肪酸合成酶,干扰素α诱导蛋白27,磷脂清除酶,丝氨酸／苏氨酸样激酶,锚着黏附蛋白以及纤维微丝蛋白-5等。结论 成功建立了筛选FasL相互作用蛋白的酵母双杂交系统,并初步证明FasL与组织蛋白酶、金属硫蛋白、锚着黏附蛋白等之间的相互作用与大肠癌肝转移密切相关。     

Treatment of fixed thoracolumbar kyphosis in immature achondroplastic patient: posterior column resection combined with segmental pedicle screw fixation and posterolateral fusion

A 13-year-old male achondroplastic dwarf with fixed thoracolumbar kyphosis was treated by segmental pedicle screw fixation, posterolateral fusion combined with one stage two level posterior column resection. Preoperative and postoperative kyphosis angles were 97 and 32°, respectively. Combination of segmental pedicle instrumentation with posterior column resection is a treatment option even in immature achondroplastic patients.A reviewers comment on this paper is available at http://dx.doi.org/10.1007/s00586-003-0596-x     

Identification of a novel receptor-like protein kinase that interacts with a geminivirus nuclear shuttle protein

Despite extensive studies in plant virus-host interactions, the molecular mechanisms of geminivirus movement and interactions with host components remain largely unknown. A tomato kinase protein and its soybean homolog were found to interact specifically with the nuclear shuttle protein (NSP) of Tomato golden mosaic virus (TGMV) and Tomato crinkle leaf yellows virus (TCrLYV) through yeast two-hybrid screening and in vitro protein binding assays. These proteins, designated LeNIK (Lycopersicon esculentum NSP-Interacting Kinase) and GmNIK (Glycine max NIK), belong to the LRR-RLK (leucine rich-repeat receptor-like kinase) family that is involved in plant developmental processes and/or resistance response. As such, NIK is structurally organized into characteristic domains, including a serine/threonine kinase domain with a nucleotide binding site at the C-terminal region, an internal transmembrane segment and leucine-rich repeats (LRR) at the N-terminal portion. The potential significance of the NSP-NIK interaction is discussed.     

Expression of adhesion molecules and Ki-67 in female adnexal tumor of probable Wolffian origin (FATWO): report of two cases and review of the literature

Female adnexal tumor of probable Wolffian origin (FATWO) is a rare entity which is believed to originate from mesonephric (Wolffian) remnants on the basis of its location where the remnants are abundant. Its behavior is usually indolent, although some cases can recur or metastasize. The authors present the clinicopathological features of two cases of FATWO arising in the broad ligament, and focus on the expression of adhesion molecules and proliferative marker. Mesonephric duct remnants are also examined in an attempt to elucidate the histogenesis of FATWOs. The two FATWOs were well-circumscribed solid masses arising in the leaves of the broad ligament and histological examination revealed a mixture of cysts and tubules imparting a sieve-like pattern and mucin-negative eosinophilic secretion within these tubules. Immunohistochemically, the tumors showed the expression of cytokeratin 7 and 20, high-molecular-weight cytokeratin, and calretinin, which closely resembled that of the mesonephric duct remnants. Regarding CK 20, CD 10, EMA, S-100 protein, and vimentin their expression was in part not identical with previous studies. E-cadherin, alpha and beta-catenin were strongly expressed along the cell membrane of the tumor cells. The Ki-67 labeling index of FATWO was 0% and 3.2% in each case. The preservation of the E-cadherin-catenin complex and low Ki-67 labeling index could explain the indolent behavior and low malignant potential of this tumor.     

Comprehensive identification of "druggable" protein ligand binding sites

We have developed a new computational algorithm for de novo identification of protein-ligand binding pockets and performed a large-scale validation of the algorithm on two systematically collected datasets from all crystallographic structures in the Protein Data Bank (PDB). This algorithm, called DrugSite, takes a three-dimensional protein structure as input and returns the location, volume and shape of the putative small molecule binding sites by using a physical potential and without any knowledge about a potential ligand molecule. We validated this method using 17,126 binding sites from complexes and apo-structures from the PDB. Out of 5,616 binding sites from protein-ligand complexes, 98.8% were identified by predicted pockets. In proteins having known binding sites, 80.9% were predicted by the largest predicted pocket and 92.7% by the first two. The average ratio of predicted contact area to the total surface area of the protein was 4.7% for the predicted pockets. In only 1.2% of the cases, no "pocket density" was found at the ligand location. Further, 98.6% of 11,510 binding sites collected from apo-structures were predicted. The algorithm is accurate and fast enough to predict protein-ligand binding sites of uncharacterized protein structures, suggest new allosteric druggable pockets, evaluate druggability of protein-protein interfaces and prioritize molecular targets by druggability. Furthermore, the known and the predicted binding pockets for the proteome of a particular organism can be clustered into a "pocketome", that can be used for rapid evaluation of possible binding partners of a given chemical compound.     

Does an enzyme other than thrombin contribute to unexpected changes in the levels of the different forms of thrombin activatable fibrinolysis inhibitor in patients with hemophilia A, hemophilia B and von Willebrand disease?

Pro-thrombin activatable fibrinolysis inhibitor (pro-TAFI), also called plasma procarboxypeptidase B or U, is one of the modulators of fibrinolysis in blood. Pro-TAFI is activated by thrombin/thrombomodulin complex or by plasmin to a carboxypeptidase B-like enzyme (TAFI) of 35.8 kD molecular weight. TAFI spontaneously becomes inactive as a result of a temperature-dependent conformational change in the protein (TAFIi). In this study, pro-TAFI, total TAFI antigen and TAFI-TAFIi antigen levels were measured in 32 patients with hemophilia A, 4 patients with hemophilia B, 21 patients with von Willebrand disease (VWD) and 13 healthy controls. A statistically significant decrease in pro-TAFI was found in all groups (10.72+/-4.57 mg/L (p<0.001); 8.00+/-2.35 mg/L (p<0.01) and 8.98+/-2.33 mg/L (p <0.001) for hemophilia A, hemophilia B and VWD, respectively) compared to controls (17.85+4.61 mg/L). A statistically significant increase in TAFI-TAFIi antigen was found in hemophilia A (1.05+/-1.01 mg/L) (p<0.05) and in VWD patients (0.96+/-1.01 mg/L) (p<0.05) compared to controls (0.55+/-0.36 mg/L). There was no difference in total TAFI antigen levels between any group of patients and the controls. Neither did pro-TAFI nor TAFI-TAFIi levels differ within the group of hemophilia A patients in relation to severity (mild, moderate and severe) or among the VWD patients in relation to subtype (type 1, type 2A and type 3). These findings indicate an increased conversion of pro-TAFI to TAFI and/or TAFIi in patients with bleeding disorders. As thrombin generation is seriously impaired in these patients and almost absent in hemophilia A and B and in type 3 VWD, it is possible that plasmin mediates pro-TAFI activation in these patients. Enhanced fibrinolysis via generation of plasmin has previously been reported in hemophilia and VWD. Activation of pro-TAFI by plasmin may be a feedback mechanism that counterbalances increased fibrinolysis in patients with bleeding disorders. The relationship between the TAFI activation pathway and bleeding complications associated with hemophilia A, hemophilia B and VWD requires further investigation.     

短串联重复序列聚合酶链反应产前诊断多胎妊娠合子性质及常见染色体三体

目的 产前诊断多胎妊娠的合子性质并检测染色体21三体、18三体、13三体和性染色体三体异常。方法 选择因各种指征产前诊断或拟行选择性减胎的多胎妊娠17例38个胎儿,抽取羊水或脐血及其父母外周血,采用短串联重复序列聚合酶链反应(short tandem repeat and polymerase chain reaction,STR-PCR)技术检查胎儿的合子性质,同时检查有无上述染色体异常;选择18个单胎妊娠产前诊断胎儿及其父母的样本,作为染色体三体检测的对照组。结果 7例体外受精胚胎移植的多胎妊娠均为多合子;7例伴有1胎畸形的多胎妊娠,仅1例为双合子双胎。本组多胎妊娠胎儿未发现有上述染色体三体异常。对4例多合子多胎于妊娠中期行减胎术,预后良好。结论 STR-PCR技术可快速、准确鉴定多胎合子性质,同时诊断胎儿染色体三体,有助于多胎妊娠的产前监测;当出现1胎畸形和拟行减胎术时,有助于选择处理方式。