Cannulated compression screw versus dynamic hip screw-blade in the treatment of femoral neck fractures / 中华创伤骨科杂志

Objective To compare the curative effect and biomechanical performance of cannulated compression screw (CCS) and dynamic hip screw-blade (DHS-B) in the treatment of patients with femoral neck fracture.Methods Between February 2010 and February 2014,102 patients with femoral neck fracture were treated with CCS or DHS-B at our department.They were 54 males and 48 females,aged from 15 to 86 years.There were 30 subcapital fractures,51 transcervical ones and 21 base ones.CCS was used in 60 patients and DHS-B in 42.In-hospital data were collected retrospectively to compare the curative effects in 2 groups.Furthermore,femoral neck fracture models were established using 12 adult cadaveric femoral specimens.The 12 models were randomized into 2 equal groups (n =6).Group A was subjected to fixation by 3 CCSs and group B to fixation by DHS-B.The 2 groups were compared in terms of axial loading test,rotation test and destructive axial loading test.Results The operation time (59.4 ± 20.2 min),incision size (4.1 ±0.6 cm) and intraoperative blood loss (25.9 ±9.9 mL) in the CCS group were significantly less than those in the DHS-B group (88.6±22.9 min,12.1 ±1.2cmand 156.7±107.1 mL) (P ＜0.05).The Harris hip score for the DHS-B group (91.9±9.8) was significantly higher than that for the CCS group (87.2 ± 9.2) (P ＜ 0.05).There were no significant differences between the 2 groups in hospital stay,partial weight-bearing time,or postoperative complications (P ＞ 0.05).At 500 N vertical loading,the stress values at both medial and lateral sides of the femur in group A were significantly smaller than those in group B (P ＜ 0.05).There were no significant differences between groups A and B in the average sinking displacement of femoral head or the torque at a torsion angle of 6° (P ＞ 0.05).The maximum load in group A (2,135 ±120 N) was significantly smaller than that in group B (2,986 ± 98 N) (P ＜ 0.05).Conclusion In treatment of femoral neck fracture,DHS-B fixation is obviously superior to CCS fixation,because the former is in better agreement with the femoral biomechanical property,and performs better in anti-rotation and anti-compression,leading to better functional recovery of the affected hip.

Identification of novel partner proteins of PCBP1 / 北京大学学报(医学版)

Objective: PCBP1 is a family member of heterogeneous nuclear ribonucleoproteins (hnRNPs) that belong to RNA-binding proteins and bear three KH domains. The protein plays a pivotal role in post-transcriptional regulation for RNA metabolism and RNA function in gene expression. We hy-pothesized and were going to identify that the regulatory function of PCBP1 is performed through different complexes of proteins that include PCBP1. Methods: To test our hypothesis, approaches of protein wal-king with a yeast two-hybrid system (Y2H), pulling down in yeasts, co-immunoprecipitation and immu-nofluorescent microscopy assay were employed in this study. The PCBP1 was used as the initial "walker" to search for its interaction partner(s). Results: Candidate proteins including MYL6, PECAM1, CSH1,RAB7, p57KIP2, ACTG1, RBMS1 and PSG4-1ike were identified with selection mediums and preceding methods. Conclusion: With these candidate protein molecules, some protein complexes associating with PCBP1 are proposed, which may help in a better understanding of physiological functions of PCBP1 and proved evidence that PCBP1 is involved in variant biological pathways.

N-terminal segments are the functional domains of CLN3-encoded battenin for protein interactions / 北京大学学报(医学版)

Objective: Batten disease (BD), the juvenile form of neuronal ceroid lipofuscinosis (NCLs), is pathological characterized by finding lysosomal storage of autofluorescent lipofuscins with unique ultrastructural profiles. The gene underlying BD is designated CLN3 and encodes a protein, Battenin, of unknown function that localizes in lysosomes and/or mitochondria. Previously, we hypothesized that Battenin associates with other membrane protein(s) to form a membrane complex. Dysfunction of this complex could result in the pathological changes of BD, and possibly in other NCLs. Two such membranous proteins, the slow and fast Battenin-interactive proteins (BIPs and BIPf) of unknown functions, have been identified. In this study, we have characterized the functional domains of Battenin that interact with both BIP proteins. Methods: Protein-protein interactions with a yeast two-hybrid system were employed. A "deletion assay" was employed to localize the interactive segment(s). Different lengths of cDNA sequences lacking exon 1-5 were used to express CLN3-encoded proteins lacking N-terminal segments in the yeast two-hybrid system. N-terminal exons of CLN3 were deleted with PCR-cloning strategies.Results: We eliminated the possibility of interacting domains from the exon 7-encoded region because both Battenin and mBattenin interact with the BIP proteins. We have shown that peptide sequences encoded by exons 2 and 4 of CLN3 gene include the functional domains by which Battenin interacts with the BIP proteins. Conclusion: Our studies provide evidence that the N-terminus of Battenin is the functional domain for these protein interactions.

Genotype-phenotype analyses of classic neuronal ceroid lipofuscinosis (NCLs): genetic predictions from clinical and pathological findings / 北京大学学报(医学版)

Objective:Genotype-phenotype associations were studied in 517 subjects clinically affected by classical neuronal ceroid lipofuscinosis (NCL). Methods:Genetic loci CLN1-3 were analyzed in regard to age of onset, initial neurological symptoms, and electron microscope (EM) profiles. Results: The most common initial symptom leading to a clinical evaluation was developmental delay (30%) in NCL1, seizures (42.4%) in NCL2, and vision problems (53.5%) in NCL3. Eighty-two percent of NCL1 cases had granular osmiophilic deposits (GRODs) or mixed-GROD-containing EM profiles; 94% of NCL2 cases had curvilinear (CV) or mixed-CV-containing profiles; and 91% of NCL3 had fingerprint (FP) or mixed-FP-containing profiles. The mixed-type EM profile was found in approximately one-third of the NCL cases. DNA mutations within a specific CLN gene were further correlated with NCL phenotypes. Seizures were noticed to associate with common mutations 523G>A and 636C>T of CLN2 in NCL2 but not with common mutations 223G>A and 451C>T of CLN1 in NCL1. Vision loss was the initial symptom in all types of mutations in NCL3. Surprisingly, our data showed that the age of onset was atypical in 51.3% of NCL1 (infantile form) cases, 19.7% of NCL2 (late-infantile form) cases, and 42.8% of NCL3 (juvenile form) cases.Conclusion:Our data provide an overall picture regarding the clinical recognition of classical childhood NCLs. This may assist in the prediction and genetic identification of NCL1-3 via their characteristic clinical features.