Carbodiimide-Derivatized Synovial Fluid for Tendon Graft Coating Improves Long-Term Functional Outcomes of Flexor Tendon Reconstruction

BACKGROUND

Flexor digitorum profundus (FDP) tendon injury is common in hand trauma, and flexor tendon reconstruction is one of the most challenging procedures in hand surgery because of severe adhesion that exceeds 25% and hinders hand function. The surface properties of a graft from extrasynovial tendons are inferior to those of the native intrasynovial FDP tendons, which has been reported as one of the major causations. Improved surface gliding ability of the extrasynovial graft is needed. Thus, this study used carbodiimide-derivatized synovial fluid and gelatin (cd-SF-gel) to modify the surface of the graft, thus improving functional outcomes using a dog in vivo model.

METHODS

Forty FDP tendons from the second and fifth digits of 20 adult women underwent reconstruction with a peroneus longus (PL) autograft after creation of a tendon repair failure model for 6 weeks. Graft tendons were either coated with cd-SF-gel ( n = 20) or not. Animals were euthanized 24 weeks after reconstruction, and digits were collected after the animals were euthanized for biomechanical and histologic analyses.

RESULTS

Adhesion score (cd-SF-gel, 3.15 ± 1.53; control, 5 ± 1.26; P < 0.00017), normalized work of flexion (cd-SF-gel, 0.47 ± 0.28 N-mm/degree; control, 1.4 ± 1.45 N-mm/degree; P < 0.014), and distal interphalangeal joint motion (cd-SF-gel, 17.63 ± 6.77 degrees; control, 7.07 ± 12.99 degrees; P < 0.0015) in treated grafts all showed significant differences compared with nontreated grafts. However, there was no significant difference in repair conjunction strength between the two groups.

CONCLUSION

Autograft tendon surface modification with cd-SF-gel improves tendon gliding ability, reduces adhesion formation, and enhances digit function without interfering with graft-host healing.

CLINICAL RELEVANCE STATEMENT

The authors demonstrate a clinically relevant and translational technology by using the patient's own synovial fluid to "synovialize" an autologous extrasynovial tendon graft to improve functional outcomes following flexor tendon reconstruction.

Canceling Notch Improves the Mechanical Safety of Clavicle Locking Plate: A 3D Finite Element Study

OBJECTIVE

Implant failure is a disastrous complication of the operative treatment of midshaft clavicle fractures, and improving the osteosynthesis plate is a strategy for preventing this. We aimed to investigate whether canceling the notch and adding screw-hole inserts enhanced the mechanical properties of the plate.

METHODS

A clavicle model was generated based on the CT images of six adult volunteers (age range, 20-40 years; three males and three females; height range 160-175) using dedicated software, and a midshaft fracture model was created. The domestically made seven-hole locking plate commonly used for midshaft clavicle fractures was simulated (Model I); modifications were made to the plate (Model II). Using 3D finite element analysis, we simulated the fracture construct under three different load conditions-downward cantilever bending, axial compression, and axial torsion-and compared the stress distribution.

RESULTS

We found that under axial compression, Model II experienced its maximum stress on the plate at 551.9MPa, which was less than that in Model I (790.4 MPa). Moreover, a greater stress concentration at the fracture site was observed under axial torsion, despite the maximum stress of both the models being similar.

CONCLUSION

Canceling the notch and filling the screw holes near the fracture can ameliorate stress concentration on the internal fixation construct and enhance its reliability under axial compression. This improvement has substantial effects on the mechanical properties of implants and potentially prevents implant failure. Modern osteosynthesis anatomical implants need to be improved.

A Novel and Open Classification Emphasizing on Osteoligamentous Complex for Distal Clavicle Fractures

OBJECTIVE

Current X-ray-based classification methods cannot describe all distal clavicle fracture (DCF) patterns, especially the osteoligamentous injury pattern of DCFs. We aimed to develop a novel classification based on the osteoligamentous injury pattern of the DCFs and investigated its reliability.

METHODS

All DCFs from January 2017 to January 2022 were respectively screened and 45 cases (mean age 20-78; male 31, female 14) met the including criteria and were enrolled. Based on their Zanca view X-ray radiograph and three-dimensional CT construction images, we analyzed the osteoligamentous injury pattern of each case, particularly the acromioclavicular (AC) and coracoclavicular ligaments and their bone attachment. Then we developed a novel classification method, five types in total, sorting all DCFs according to their lesion manifestations of osteoligamentous complex. Also, we investigated the inter- and intra-observer reliability using kappa value.

RESULTS

A novel classification method for DCF was developed, manifesting the avulsion or rupture of conoid and trapezoid ligaments, and involvement of AC joint. Forty-five cases of DCFs were included in this study. Among them, 11 (24.4%) were Type 1 fracture, three (6.7%) cases were Type 2, six cases (13.3%) were Type 3, 21 (46.7%) were Type 4, four (8.9%) were Type 5. Kappa values for inter-observer agreement were 0.57 after first evaluation and 0.61 after second evaluation. Intra-observer agreement was 0.72 for experienced shoulder specialist and 0.63 for radiologist.

CONCLUSION

This new classification method is reliable to use, supplementary to current classification systems, and emphasizes on the osteoligamentous complex injury when opting for the treatment.

Clinical Application of Nail-Plate Fixation in the Treatment of Complex Proximal Third Humeral Fracture: A Case Report and Literature Review

BACKGROUND

Proximal humeral fractures with increasing incidence are common over the past decades. Among them, the complicated and displaced ones, especially combined with the proximal third humeral shaft fractures, need to be treated surgically. Humeral intramedullary nail and locking plate are the most frequently used options. However, few studies address the application of nail-plate combination for management.

CASE PRESENTATION

A 49-year-old man struck by a car was referred to our emergency trauma center. The X-ray and three-dimensional computed tomography (CT) showed a complex proximal humeral fracture with proximal third shaft fracture. No evidence of other associated injuries and neurovascular symptom of the injured left upper limb was shown by physical examination. Nail-plate fixation was performed to restore the anatomic integrity of proximal humerus. The injured arm was maintained in a broad arm sling for 14 days after surgery. The active as well as positive movements under the instruction were encouraged as long as the pain could be tolerated from postoperative day 2. One year after the surgery, the fracture was healed, and the patient regained normal shoulder motion. The good clinical outcomes were obtained by application of nail-plate fixation to treat complex proximal third humeral shaft fractures. Thus, this surgical intervention could be performed as an alternative.

miR-185-5p / ATG101 axis alleviated intestinal barrier damage in intestinal ischemia reperfusion through autophagy

Objective

Intestinal ischemia-reperfusion (II/R) is a common pathological injury in clinic, and the systemic inflammatory response it causes will lead to multiple organ damage and functional failure. miR-185-5p has been reported to be a regulator of inflammatory response and autophagy, but whether it participates in the regulation of autophagy in II/R is still unclear. Therefore, we aimed to explore the mechanism of miR-185-5p regulating intestinal barrier injury in (II/R).

Methods

Caco-2 cells was induced by oxygen-glucose deprivation/reoxygenation (OGD/R) to establish II/R model. The superior mesenteric artery of C57BL/6 mice was clamped for 45 min and then subjected to reperfusion for 4 h for the establishment of II/R mice model. miR-185-5p mimic, miR-185-5p inhibitor, pcDNA-autophagy-related 101 (ATG101) were respectively transfected into Caco-2 cells. Real-time quantitative polymerase chain reaction (RT-qPCR) was performed to assess miR-185-5p expression. Western blot detected the level of ATG101 and tight junction-associated proteins ZO1, Occludin, E-cadherin, β-catenin, as well as autophagy markers ATG5, ATG12, LC3Ⅰ/Ⅱ, Beclin1 and SQSTM1. Transepithelial electrical resistance (TEER) values was detected by a resistance meter. FITC-Dextran was performed to measure cell permeability. 5-ethynyl-2'-deoxyuridine (EDU) staining measured cell proliferation. Transmission electron microscope was conducted to observe autophagosomes. Hematoxylin & eosin (H&E) staining observed the damage of mice intestinal. Immunohistochemistry (IHC) measured the percentage of ki67 positive cells. TdT-mediated dUTP nick-end labeling (TUNEL) assay assessed cell apoptosis in intestinal tissues of II/R. Dual-luciferase assay verified the targeting relationship between miR-185-5p and ATG101.Results miR-185-5p was overexpressed in OGD/R-induced Caco-2 cells and intestinal tissues of II/R mice. Knocking down miR-185-5p markedly promoted autophagy and TEER values, reduced cell permeability, and alleviated intestinal barrier damage. ATG101 was a target of miR-185-5p, and overexpression of ATG101 promoted autophagy and dampened OGD/R-induced intestinal barrier damage. Overexpression of miR-185-5p reversed the effect of overexpressed ATG101 on OGD/R-induced Caco-2 cells.

Conclusion

Knockdown of miR-185-5p enhanced autophagy and alleviated II/R intestinal barrier damage by targeting ATG101.

Improving Mechanical Properties of Tendon Allograft through Rehydration Strategies: An In Vitro Study

Allogenic tendons grafts sourced from intrasynovial tendons are often used for tendon reconstruction. Processing is achieved through repetitive freeze-thaw cycles followed by lyophilization. Soaking the lyophilized tendon in saline (0.9%) for 24 h is the standard practice for rehydration. However, data supporting saline rehydration over the use of other hydrating solutions are scant. The purpose of the current study was to compare the effects of different rehydration solutions on biomechanical properties of lyophilized tendon allograft. A total of 36 canine flexor digitorum profundus tendons were collected, five freeze-thaw cycles followed by lyophilization were performed for processing, and then divided into three groups rehydrated with either saline solution (0.9%), phosphate-buffered saline (PBS), or minimum essential medium (MEM). Flexural stiffness, tensile stiffness, and gliding friction were evaluated before and after allograft processing. The flexural moduli in both fibrous and fibrocartilaginous regions of the tendons were measured. After lyophilization and reconstitution, the flexural moduli of both the fibrocartilaginous and non-fibrocartilaginous regions of the tendons increase significantly in the saline and MEM groups (p < 0.05). Compared to the saline and MEM groups, the flexural moduli of the fibrocartilaginous and non-fibrocartilaginous regions of tendons rehydrated with PBS are significantly lower (p < 0.05). Tensile moduli of rehydrated tendons are significantly lower than those of fresh tendons for all groups (p < 0.05). The gliding friction of rehydrated tendons is significantly higher than that of fresh tendons in all groups (p < 0.05). There is no significant difference in either tensile moduli or gliding friction between tendons treated with different rehydration solutions. These results demonstrate that allograft reconstitution can be optimized through careful selection of hydrating solution and that PBS could be a better choice as the impact on flexural properties is lower.

Efficacy and safety of anti-angiogenesis agents combined with chemoradiotherapy in the treatment of locally advanced cervical cancer: a meta-analysis of randomized controlled trials

BACKGROUND

Neovascularization is an important factor causing radiotherapy resistance, tumor growth, and metastasis. It may provides a new direction for treatment of cervical cancer.

OBJECTIVE AND METHODS

The main objective is to systematically evaluate the clinical efficacy and safety of antiangiogenic therapy combined with CCRT in the treatment of cervical cancer. We searched major Chinese and English databases to collect relevant studies from the database establishment up to April 2022. The experimental group of the studies included used CCRT combined with anti-angiogenic therapy, while another used only CCRT. We used the 'Cochrane Collaboration's tool' to assess risk of bias and RevMan 5.4 to conduct analysis.

RESULTS

Twelve studies with 793 patients were included. Use clinical efficiency and adverse reactions as effect indicators. It showed that the combination can improve the ORR (OR = 3.52, P < 0.00001), CR(OR = 2.46, P < 0.00001), DCR (OR = 2.64, P= 0.005), and OS(HR = 0.56, P = 0.03). But it increases the risk of neutropenia (OR = 1.86, P = 0.004) and hypertension (OR = 5.57, P = 0.003).

CONCLUSIONS

Combined therapy can improve the clinical efficacy of cervical cancer, but the safety needs to be considered.

Morphological specificity analysis of an image-based 3D model of airway filling in a difficult airway

Background

The purpose of this study was to analyze position-specific morphological changes of the upper airway and to further assess the impact of these changes in difficult airway during intubation.

Methods

This observational comparative study included two groups (n = 20 patients/group): Group A had normal airway and Group B had difficult airway. Data obtained from two-dimensional magnetic resonance imaging were imported to Mimics V20.0 software for processing. We then reconstructed three-dimensional models of upper airway filling in patients in the supine and maximum extension position based on the imaging data. Those models were projected on coronal, sagittal, and horizontal planes to investigate multiple morphological features. We measured the surface area, radial length, and corner angle of the projected areas.

Results

Group A had larger upper airway filling volumes compared to Group B The volumes for the supine position were 6,323.83 ± 156.06 mm3 for Group A and 5,336.22 ± 316.13 mm3 for Group B (p = 0.003). The volumes the maximum extension position were 9,186.58 ± 512.61 mm3 for Group A and 6,735.46 ± 794.63 mm3 for Group B (p = 0.003). Airway volume increased in the upper airway filling model as the body position varied from the supine to maximum extension position (Group A: volume increase 2,953.75 ± 524.6 mm3, rate of change 31%; Group B: volume increase 1,632.89 ± 662.66 mm3, rate of change 25%; p = 0.052).

Conclusion

The three-dimensional reconstruction model developed in this study was used to digitally quantify morphological features of a difficult airway and could be used as a novel airway management assessment tool.

Construction of multifunctional porcine acellular dermal matrix hydrogel blended with vancomycin for hemorrhage control, antibacterial action, and tissue repair in infected trauma wounds

Prevention of bacterial infection and reduction of hemorrhage, the primary challenges posed by trauma before hospitalization, are essential steps in prolonging the patient's life until they have been transported to a trauma center. Extracellular matrix (ECM) hydrogel is a promising biocompatible material for accelerating wound closure. However, due to the lack of antibacterial properties, this hydrogel is difficult to be applied to acute contaminated wounds. This study formulates an injectable dermal extracellular matrix hydrogel (porcine acellular dermal matrix (ADM)) as a scaffold for skin defect repair. The hydrogel combines vancomycin, an antimicrobial agent for inducing hemostasis, expediting antimicrobial activity, and promoting tissue repair. The hydrogel possesses a porous structure beneficial for the adsorption of vancomycin. The antimicrobial agent can be timely released from the hydrogel within an hour, which is less than the time taken by bacteria to infest an injury, with a cumulative release rate of approximately 80%, and thus enables a relatively fast bactericidal effect. The cytotoxicity investigation demonstrates the biocompatibility of the ADM hydrogel. Dynamic coagulation experiments reveal accelerated blood coagulation by the hydrogel. In vivo antibacterial and hemostatic experiments on a rat model indicate the healing of infected tissue and effective control of hemorrhaging by the hydrogel. Therefore, the vancomycin-loaded ADM hydrogel will be a viable biomaterial for controlling hemorrhage and preventing bacterial infections in trauma patients.

Axial Micromotion Locking Plate Construct Can Promote Faster and Stronger Bone Healing in an Ovine Osteotomy Model

Fixing bone fractures with controlled axial interfragmentary micromotion improves bone healing; however, the optimal type of implant construct for this purpose is still lacking. The present study describes a novel axial micromotion locking plate (AMLP) construct that allows axial interfragmentary micromotion of 0.3 or 0.6 mm. We investigated whether the AMLP constructs enhance bone healing compared to an ordinary locking plate (LP) using an ovine osteotomy model. The stiffness of the constructs was tested under axial loading. We created a 3-mm osteotomy in the left hind leg tibia of sheep that was then stabilized with a 0.3- or 0.6-mm AMLP or LP construct (n = 6/group). Bone healing was monitored weekly by X-ray radiography starting from week 3 after surgery. At week 9, the specimens were collected and evaluated by computed tomography and torsional testing. We found that the AMLPs had a lower stiffness than the LP; in particular, the stiffness of the 0.6-mm AMLP construct was 86 and 41% lower than that of the LP construct for axial loads <200 and >200 N, respectively. In the in vivo experiments, tibial osteotomies treated with the 0.6-mm AMLP construct showed the earliest maximum callus formation (week 5) and the highest volume of bone callus (9.395 ± 1.561 cm³ at week 9). Specimens from this group also withstood a 27% greater torque until failure than those from the LP group (P = 0.0386), with 53% more energy required to induce failure (P = 0.0474). These results demonstrate that AMLP constructs promote faster and stronger bone healing than an overly rigid LP construct. Moreover, better bone healing was achieved with an axial micromotion of 0.6 mm as compared to 0.3 mm.

Study of charged particle activation analysis (II): Determination of boron concentration in human blood samples

Boron Neutron Capture Therapy (BNCT) is a radiotherapy for the treatment of intractable cancer. In BNCT precise determination of ¹⁰B concentration in whole blood sample before neutron irradiation of the patient, as well as accurate neutron dosimetry, is crucial for control of the neutron irradiation time. For this purpose ICP-AES and neutron induced prompt γ-ray analysis are generally used. In Ibaraki Neutron Medical Research Center (iNMRC), an intense proton beam will be accelerated up to 8 MeV, which can also be used for Charged Particle Activation Analysis (CPAA). Thus, in this study, we apply the CPAA utilizing the proton beam to non-destructive and accurate determination of ¹⁰B concentration in whole blood sample. A CPAA experiment is performed by utilizing an 8 MeV proton beam from the tandem accelerator of Nuclear Science Research Institute in Japan Atomic Energy Agency. The 478 keV γ-ray of ⁷Be produced by the ¹⁰B(p, α)⁷Be reaction is used to quantify the ¹⁰B in human blood. The 478 keV γ-ray intensity is normalized by the intensities of the 847 keV and 1238 keV γ-rays of ⁵⁶Co originating from Fe in blood. The normalization methods were found to be linear in the range of 3.27 μg ¹⁰B/g to 322 μg ¹⁰B/g with correlation coefficients of better than 0.9999.

Management of Dislocation of the Shoulder Joint with Ipsilateral Humeral Shaft Fracture: Initial Experience

Objective

To gain a better understanding of the traumatic mechanism and to develop appropriate treatment for dislocation of the shoulder joint with an ipsilateral humeral shaft fracture.

Methods

This was an observational and descriptive study. Nine patients with traumatic shoulder dislocations associated with ipsilateral humeral shaft fractures who visited the emergency room and received treatment from January 2012 to June 2018 were retrospectively analyzed. CT with three‐dimensional reconstruction was performed to provide precise anatomical information of the fractures. The traumatic event and the type of fracture of the humeral shaft were analyzed to help determine the trauma mechanism. Closed reduction of the dislocation was attempted at once under intravenous anesthesia. One patient died the following day due to unrelated causes. All humeral shaft fractures of the eight patients received internal fixation, and then reduction of the dislocation was performed again if previous attempts failed. The affected limb was immobilized in a sling for 3 weeks postoperatively, and then active and passive movement was encouraged. Patients were evaluated based on clinical and radiographic examinations, shoulder joint range of motion, Constant–Murley score, and subjective shoulder value.

Results

Four cases in the present study could not give a clear description of the traumatic procedure. The other five patients suffered a second strike on their upper arms when they were hurt, with low mobility and high pain in the shoulder region. Seven cases were simple fractures and two were wedge fractures. According to the AO/OTA classification system, four cases were type 12‐A2, three were type 12‐A3, and two were type 12‐B2. Six patients successfully obtained closed manipulative reduction of the shoulder dislocation in the acute stage. The follow‐up time ranged from 18 to 31 months. No deep wound infections were encountered. All fractures healed uneventfully. The union time ranged from 4 to 6 months. At the final follow‐up, shoulder range‐of‐motion values were found to range from 140° to 170° forward flexion, 30° to 40° extension, 40° to 45° adduction, 150° to 170° abduction, 50° to 60° internal rotation, and 50° to 60° external rotation; no recurrent instability of the shoulder joint occurred; the Constant–Murley score was 89.5 ± 3.7 points (range: 84–94 points); the subjective shoulder value was 89.4% ± 6.3% (range: 75%–95%).

Conclusion

Shoulder dislocation most likely occurs first with an axial force or a direct posteroanterior force and a subsequent force results in the shaft fracture. For patients with mid‐distal humerus fractures, closed manipulative reduction of the joint is usually effective. After success of closed reduction, surgery for the humeral shaft fracture is advocated to ensure stability and to make patient nursing convenient. In cases with fractures in the proximal third of the humeral shaft, fixation is suggested beforehand to help reduce the shoulder dislocation.

Diagnostic value of intraoperative tap test for acute deltoid ligament injury

PURPOSE

Deltoid ligament injuries appear with isolated or even no displacement of the lateral malleolus fracture which could easily lead to misdiagnosis, which frequently brings about ankle medial instability and talus shift that eventually lead to the occurrence of ankle osteoarthritis. This study is aimed to investigate the value of the tap test for assessing the integrity of the deltoid ligament intraoperatively.

METHODS

Ninety-two patients with malleolar fractures and possible acute deltoid ligament injury treated in our hospital from March 2013 to May 2016 were enrolled in this prospective study. The gravity stress test and tap test were performed preoperatively by three physicians independently before and after fixation of the fibula. The sensitivity, specificity, positive and negative predictive values, and false-positive and false-negative rates of both tests were determined based on medial malleolus exploration for the integrity of the deltoid ligament. The inter-observer consistency was also analyzed.

RESULTS

Forty seven (51.1%) versus fifty two (56.5%) of the 92 patients tested positive for deltoid ligament injury according to the preoperative gravity stress test or the subsequent tap test. Forty-eight cases (52.2%) were confirmed during surgery. The sensitivity of gravity stress test was lower than that of tap test (95.8% vs 100%), and specificity of gravity stress test was the same as tap test (97.7% vs 97.7%). Between gravity stress test and tap test, the positive and negative predictive values were 97.9% vs 92.3% and 95.6% vs 100%, and the false-positive and false-negative rates were 2.3% vs 9.09% and 4.2% vs 0%, respectively. Between the two tests results, the percentage of inter-observer agreement was > 90% (kappa coefficient > 0.80).

CONCLUSION

The tap test has the advantages of high sensitivity, simple operation, and less radiation exposure, suggesting that it is of high diagnostic value for assessing the integrity of the acute deltoid ligament.

Clinical and radiological short-term outcomes of pubic symphysis diastasis treated with modified pedicle screw-rod fixation

PURPOSE

Pubic symphysis diastasis with an incidence of approximately 20% in pelvic fractures is a severe lesion which needs to be treated properly. The objective of this retrospective study was to describe and evaluate the clinical and radiological outcomes including its advantages and limitations of this modified minimal invasive technique.

METHODS

Totally 29 patients with pubic symphysis diastasis, with or without posterior ring instability, were treated by modified pedicle screw-rod fixation (modified PSRF) between January 2010 and December 2016. The duration from injury to surgery, operation time, intraoperative blood loss as well as complications were recorded. During follow-up, the functional outcomes were assessed according to the Majeed evaluation criteria 1 year postoperatively. The evaluation of the postoperative reduction quality was carried out according to Matta criteria.

RESULTS

According to Tile classification, there were 9 cases of Type B1 underwent only anterior-modified PSRF and 20 cases of Type C1 experienced anterior-modified PSRF combined with posterior fixation. The duration from injury to operation, operation time and intraoperative blood loss were 3.27 days (range 1-6 days), 42.07 min (range 38-45 min), and 46.14 ml (range 40-55 ml). The results of reduction quality were rated as excellent in 16, good in 11 and fair in 2 based on Matta criteria. The Majeed functional scores ranged from 68 to 95 and there were excellent in 15, good in 12 and fair in 2. No patients experienced incision infection. Slight loosening of middle-two screws was verified during follow-up in one patient. Two patients underwent femoral nerve palsy. Irritation to the LFCN was detected in four patients.

CONCLUSIONS

Modified PSRF can be performed as an alternative to manage pubic symphysis diastasis due to its merits of minimal invasive, less blood loss, less soft tissue injuries as well as shorter operation time, even with the early weight-bearing.

TRIAL REGISTRATION

Researchregistry3905.

The effects of lyophilization on flexural stiffness of extrasynovial and intrasynovial tendon

Tendon or ligament reconstructions often use autologous or allogenic tendons from either extrasynovial or intrasynovial sources. Allograft tendons must be lyophilized for preservation before transplantation, a process which can impact mechanical properties of the graft. Reconstituted graft properties that are similar to native tendon are desirable. Although tensile and compressive properties of tendons have been investigated, there is a paucity of information describing flexural properties of tendon, which can impact the gliding resistance. This study aims to design a testing method to quantify tendon flexural modulus, and investigate the effects of lyophilization/rehydration procedures on tendon flexibility. A total of 20 peroneus longus tendons (extrasynovial) and 20 flexor digitorum profundus tendons (intrasynovial) were collected. Ten of each tendon were processed with 5 freeze-thaw cycles followed by lyophilization and rehydration with saline solution (0.9%). Bend testing was conducted on tendons to quantify the flexural modulus with and without processing. As canine FDP tendons contain fibrous and fibrocartilaginous tissue regions, the flexural moduli were measured in both regions. Flexural modulus of rehydrated, lyophilized extrasynovial PL tendon was significantly lower than that of similarly processed intrasynovial FDP tendon (p < 0.001). Flexural moduli of both the fibrocartilaginous and non-fibrocartilaginous regions of intrasynovial tendon significantly increased after lyophilization (p < 0.001). The flexural modulus of the fibrocartilaginous region was significantly higher than that of the non-fibrocartilaginous region in intrasynovial tendon (p < 0.001). Lyophilization significantly increases the flexural modulus of extrasynovial and intrasynovial tendons, and flexural modulus differs significantly between these two tendon types. Increases in stiffness caused by lyophilization may impact the mechanical performance of the allograft in vivo.

True compression of pelvic fractures under lateral impact

PURPOSE

To promote the understanding of pelvic fracture mechanism and make more accurate evaluation of maximal deformity at the moment of fracture, kinematic response of pelvis to lateral impact and the difference between peak and final displacement were investigated.

METHODS

A total of three human cadaver pelves were seated uprightly on a sled test table, explored to horizontal lateral impact by a 22.1-kg impactor at a speed of 5.2, 4.0, and 4.8 m/s. Kinematic data of pelvic osseous interesting points (POIP) were measured by the motion capture system. Trajectories of POIP, duration of impact, and deflection of pelvis were calculated as well as rotational movement of pelvis was evaluated. After impact, autopsy and CT scan were made to validate the motion capture data.

RESULTS

The peak deflection of pelvis under lateral impact was 31.9, 30.1, and 18.5%, while final deflection was 19.6, 13.8, and 13.8%. The final deflection was only 61.5, 45.9, and 74.46% of the peak deflection.

CONCLUSIONS

In clinical practice, pelvic fracture displacement tends to be underestimated. The peak compression can be 1.3-2.2 times of final compression appearing on images in hospital. Clinicians shall give adequate estimation of displacement and related injuries.

Modified pedicle screw-rod fixation versus anterior pelvic external fixation for the management of anterior pelvic ring fractures: a comparative study

Background

Anterior pelvic ring fracture, as high-energy trauma, needs to be effectively treated. The purpose of the current study was to evaluate the clinical applications of modified pedicle screw-rod fixation and anterior pelvic external fixation for the treatment of anterior pelvic ring fracture.

Methods

Either modified pedicle screw-rod fixation (modified PSRF group, N = 21) or anterior pelvic external fixation (APEF group, N = 22) was performed to 43 patients, with or without fixation of posterior ring. Clinical outcomes were evaluated via Majeed scores. Relevant clinical evaluation indicators including operation time, intraoperative blood loss, hospitalization duration, and complications were compared between these two groups.

Results

The operation time in APEF group was significantly less than that in modified PSRF group (P < 0.0001). No significant difference with respect to intraoperative blood loss and hospitalization duration between the two groups was shown (P = 0.51 and P = 0.33, respectively). Six patients developed surgical site infection in APEF group. Three patients experienced loss of fixation, and two patients experienced loosening of fixator in APEF group. Temporary lateral femoral cutaneous nerve irritation occurred in three patients in modified PSRF group while two patients in APEF group. One patient experienced femoral nerve palsy in modified PSRF group. Fractures of all patients healed well eventually. No statistical difference regarding Majeed evaluation scores was found between two groups.

Conclusions

Application of both modified PSRF and APEF could provide similar satisfactory clinical outcomes for anterior pelvic ring fracture. Modified PSRF, a minimally invasive technique with the advantages of internal fixation, could be performed as an alternative method for instable pelvic fractures.

Trial registration

Research Registry UIN: researchregistry2776.

Fabella fracture with radiological imaging: A case report

The fabella is a kind of sesamoid bone which is located in the lateral head of the gastrocnemius muscle. A slice of studies demonstrated that fabella is involved in the knee joint stabilization. Fabella fracture may cause knee pain or functional impairment as the previous reports pointed. It is extremely rare, which leads to its high rate of missed diagnosis in clinical and radiography to some extent. We report a case of a 38-year-old female who was struck by an electromobile. The fabella fracture was confirmed on X-ray plain films. After that, the degree of injury was evaluated with the magnetic resonance imaging (MRI).

The safe screw path along inferior border of the arcuate line at acetabular area: an anatomical study based on CT scans

BACKGROUND

Misplaced screw during the internal fixation of acetabular fractures may penetrate the hip joint which might cause chondrolysis and traumatic osteoarthritis in the future. This study aims to acquire the safe path for screw insertion along inferior border of the arcuate line fixation route at acetabular area.

METHODS

Computed tomography (CT) scans of 98 patients without pelvic trauma were rebuilt for three-dimensional models of pelvis. After depicting the fixation route curve, five cross-sections perpendicularly to the curve were established from the anterior of pelvis to the posterior along inferior border of the arcuate line. The safe screw lengths for section 1 and 5 were measured from the computer models. In section 2, 3 and 4, a line from the screw entry point tangent to the inferior edge of the acetabulum was depicted and the measurements of minimum safe direction of screw insertion were performed then marked with angle θ.

RESULTS

The safe screw lengths for section 1 and 5 were 22.29 ± 4.41 mm and 32.64 ± 4.70 mm (n = 98). The minimum safe angles of screw insertion for the middle three sections 2, 3, and 4 were 65.38 ± 10.23°, 74.20 ± 10.20°, and 57.88 ± 11.11°(n = 98), respectively. The results for the male group (n = 98) indicated smaller minimum safe angles in these three sections compared with the female (n = 98).

CONCLUSIONS

Compared to male, the minimum safe angles of screw placement at acetabular area for female should be more away from inferior edge of acetabulum and tilt to the bottom of pelvis along inferior border fixation route in surgical management of acetabular fractures.

[Analysis of the survival of 123 patients with intrahepatic cholangiocarcinoma after surgical resection]

OBJECTIVE

To investigate the prognostic factors for patients with intrahepatic cholangiocarcinoma after surgical resection.

METHODS

The clinicopathological and follow-up data of 123 patients with intrahepatic cholangiocarcinoma who underwent surgical resection in Cancer Hospital, Chinese Academy of Medical Sciences between January 1999 and June 2015 were collected and reviewed, and their survival and prognosis were analyzed with the Kaplan-Meier method and Cox regression model.

RESULTS

The median follow-up time was 22 months and median recurrence-free survival time was 8.97 months. The 1-, 2- and 3-year recurrence rates were 58.6%, 68.9% and 76.5%, respectively. Cox multivariate regression analysis showed that preoperative rise in CEA, lymph node metastasis, multiple lesions, extrahepatic invasion, and combination of tumor necrosis were significant adverse prognostic factors affecting the postoperative recurrence-free survival in patients with intrahepatic cholangiocarcinoma after surgical resection (P<0.05 for all). The median overall survival time was 21.17 months, and the 1-, 3- and 5-year overall survival rates were 76.6%, 33.2% and 26.1%, respectively. The Cox multivariate regression analysis showed that preoperative rise in CEA, lymph node metastasis, multiple lesions, and extrahepatic invasion were significant adverse prognostic factors affecting the postoperative overall survival in patients with intrahepatic cholangiocarcinoma after surgical resection(P<0.05 for all).

CONCLUSION

Preoperative rise in CEA, lymph node metastasis, multiple lesions and extrahepatic invasion are significant adverse prognostic factors for patients with intrahepatic cholangiocarcinoma after surgical resection.

Treatment of Unstable Posterior Pelvic Ring Fracture with Pedicle Screw-Rod Fixator Versus Locking Compression Plate: A Comparative Study

Background

The aim of this study was to assess the clinical results of treatment for unstable posterior pelvic fractures using a pedicle screw-rod fixator compared to use of a locking compression plate.

Material/Methods

A retrospective study was performed between June 2010 and May 2014 and the data were collected from 46 patients with unstable posterior pelvic ring fractures. All patients were treated using either a pedicle screw-rod fixator (study group, 24 patients) or locking compression plate (control group, 22 patients). In these patients, causes of injury included traffic accidents (n=27), fall from height (n=12), and crushing accidents (n=7). The quality of reduction and radiological grading were assessed. Clinical assessments included the operation time, times of X-ray exposures, bleeding volume during operation, incision length, and Majeed postoperative functional evaluation.

Results

No iatrogenic neurovascular injuries occurred during the operations in these 2 groups. The average follow-up time was 24.5 months. All fractures were healed. The significant differences (P<0.05) between the 2 groups were operation duration, size of incision, and intraoperative bleeding volume. Statistically significant differences in the Majeed postoperative functional evaluation and times of X-ray exposures were not found between the 2 groups.

Conclusions

Similar clinical effects were achieved in treating the posterior pelvic ring fractures using the pedicle screw-rod fixator and the locking compression plate. However, the pedicle screw-rod fixator has the advantages of smaller incision, shorter duration of the operation, and less bleeding volume compared to using the locking compression plate.

Digital anatomical measurements and crucial bending areas of the fixation route along the inferior border of the arcuate line for pelvic and acetabular fractures

Background

Better understanding of three-dimensional (3D) morphology of the pelvis at the area of inferior border of the arcuate line is very important, which could guide the surgeons to treat pelvic and acetabular fractures more efficiently. The objective of this study is to provide references for screw placement and design of anatomical internal fixators for the fixation route along the pelvic inferior border of the arcuate line.

Methods

Seventy five cases of computed tomography (CT) scan data were collected using Medical Image Database in Shanghai General Hospital between December 2009 and November 2010. 44 males and 31 females, aging from 21 to 91 years (average: 57.8 years) were enrolled. Using MIMICS 13.0, these data were used for three dimensional (3D) reconstructions of pelvic model. A curve from the pubic tubercle, along the inferior border of the arcuate line, to the sacroiliac joint was depicted and then divided into 11 equal parts. The measurements of whole length of the curve, the radius of the curvature and the thickness of bone at each decile point were performed, respectively.

Results

The thinnest bone thickness at acetabular area was 17.24 ± 2.90 mm and 9.94 ± 2.69 mm for male and female, respectively. The radius of curvature at the decile points 1, 8 and 10 were smaller compared with the surrounding points.

Conclusions

Using a screw shorter than 10 mm perpendicular to the bone surface along the inferior border of the arcuate line can avoid intra-articular screw penetration. There should be more recontouring of the plate at the areas of pubic tubercle and posterior edge of the acetabulum when placing a fixator along this fixation route. This study provides solid guidance for pelvic and acetabular surgeries as well as designing of anatomical fixators along inferior border fixation route at this area.

[Influence of BMP-7 on chondrocyte secretion and expression of Col-II,AGG and Sox9 mRNA in porous tantalum-chondrocyte composites in vitro]

OBJECTIVE

To study the influence of bone morphogenetic protein-7 (BMP-7) on chondrocyte secretion and expression of type II collagen (Col-II), aggrecan (AGG) and SRY-related high mobility group-box gene 9 (Sox9) mRNA in porous tantalum-chondrocyte composites.

METHODS

The articular chondrocytes were isolated from 3-week-old New Zealand immature rabbits and identified. The 2nd generation of chondrocytes with 1×10(6)/mL inoculate concentration was seeded in porous tantalum and divided into 4 groups, and control group (tantalum/chondrocyte), 50 μg/L BMP-7 group (50 μg/L BMP-7/tantalum/chondrocyte), 100 μg/L BMP-7 group (100 μg/L BMP-7/tantalum/chondrocyte), and 200 μg/L BMP-7 group (200 μg/L BMP-7/tantalum/chondrocyte). The proliferation of chondrocytes was measured by CCK-8 assay. The chondrocyte growth and morphology were observed by scanning electron microscopy (SEM). The synthesis of glycosaminoglycan (GAG) in chondrocytes was tested by dimethyl methylene blue (DMMB) colorimetric quantification method. Col-II, AGG and Sox9 mRNA in chondrocytes were detected by real-time PCR.

RESULTS

The chondrocytes were spindle-shaped in 24 hours of primary cell culture and most cells became polygonal shaped in 4 days. The chondrocytes were affirmed by alcian blue, safranin O and Col-II immunocytochemistry staining. The result of CCK-8 assay showed that the level of cell proliferation in 100 μg/L BMP-7 groups were higher than those in the other groups (P<0.05). The chondrocytes implanted into porous tantalum scaffolds with BMP-7 had better functions, by which cytoplasmic processes developed and extended to the surface and inner of porous tantalum by SEM observation. DMMB quantitative determination of GAG showed that GAG amount of chondrocytes in 100 μg/L BMP-7 groups was significantly higher than those in the other groups (P<0.05). The expressions of Col-II, AGG and Sox9 mRNA in chondrocytes were up-regulated in the experimental groups, compared with the control group and the best effect appeared when concentration of BMP-7 was 200 μg/L. (P<0.05).

CONCLUSION

BMP-7/tantalum/chondrocytes composites enhanced in vitro chondrocyte proliferation and extracellular matrix greatly, and can promote chondrogenic gene expression.

Digital anatomical measurements of safe screw placement at superior border of the arcuate line for acetabular fractures

Background

Screw penetration into hip joint is a severe complication during acetabular fracture surgery, which might result in osteoarthritis and chondrolysis. The purpose of this study was to obtain the safe and effective screw angles and lengths at acetabular area of the fixation route along the superior border of the arcuate line.

Methods

A total of 98 uninjured pelvises of Chinese adults were examined. Each person’s computed tomography (CT) scans were reconstructed to create a three-dimensional pelvic model. A curve of the fixation route was delineated and five cross-sections from the pubic tubercle to the sacroiliac joint direction were constructed perpendicularly to the curve. The minimum safe direction, which was tangent to the acetabulum, was measured in the middle three sections and then recorded as the angle α. The maximum effective direction, which was determined by a 14 mm arc and the quadrilateral surface, was also measured in the above sections and then recorded as the angle β. The maximum screw lengths for the five sections were measured.

Results

The ranges of safe and effective screw insertion angles for the 2nd, 3rd, 4th cross-sections were 21.09±13.57°~40.45±13.60°, 30.43±14.05°~47.54±12.67°, 23.84±11.60°~37.13±8.45°, respectively. The maximum screw lengths for the five sections were 15.89±3.80 mm, 58.83±27.66 mm, 42.94±22.41 mm, 72.43±6.73 mm, 40.99±6.33 mm. The male group showed significantly greater minimum safe angle compared to the female group in the 2nd, 3rd, and 4th sections (p<0.05).

Conclusions

The screw insertion at the acetabular area for the female requires greater minimum safe angle towards the quadrilateral surface than the male.

Arthroscopic versus mini-open rotator cuff repair: an up-to-date meta-analysis of randomized controlled trials

PURPOSE

The aim of this meta-analysis was to compare the clinical outcomes of arthroscopic and mini-open rotator cuff repairs based on recently published Level I randomized controlled trials (RCTs).

METHODS

We systematically searched electronic databases to identify RCTs that compared arthroscopic and mini-open rotator cuff repairs from 1980 to October 2013. The clinical outcome scores, including the University of California, Los Angeles score and the Constant-Murley score, were converted to a common 100-point outcome score for further analysis. The results of the pooled studies were analyzed in terms of surgery time, weighted 100-point score, pain on a visual analog scale (VAS), and range of motion. Study quality was assessed and relevant data were extracted independently by 2 reviewers.

RESULTS

Five RCTs, including 166 patients in the arthroscopic repair group and 163 patients in the mini-open repair group, were included in this meta-analysis. The results of the meta-analysis showed that there were no significant differences in surgery time (P = .11), weighted 100-point score (P = .65), VAS pain score (P = .87), or range of motion (P = .29 for forward flexion and P = .82 for external rotation).

CONCLUSIONS

On the basis of current literature, no differences in surgery time, functional outcome score, VAS pain score, and range of motion were found at the end of follow-up between the arthroscopic and mini-open rotator cuff repair techniques. In addition, there was no significant difference in VAS pain score in the early phase between the 2 repairs.

LEVEL OF EVIDENCE

Level I, meta-analysis of Level I studies.

Fluxes, variability and sources of cadmium, lead, arsenic and mercury in dry atmospheric depositions in urban, suburban and rural areas

In China's largest city, Shanghai, dry deposition fluxes of Cd, Pb, As and Hg were 137, 19354, 2897 and 9.4 μgm(-2)a(-1), respectively in an urban area, intermediate in a suburban area, and 51.7, 5311, 1703 and 7.3 μgm(-2)a(-1), respectively in a rural area. Enrichment factors were Cd>Pb>As>Hg. Seasonal variations of metals differed: Pb and As were dominated by fossil fuel combustion, Cd was related to industrial pollution, and natural source controlled Hg levels.

Effect of dasatinib against thyroid cancer cell lines in vitro and a xenograft model in vivo

Tyrosine kinase inhibitors (TKIs) have emerged as a promising class of agents against thyroid cancer. The aim of the present study was to investigate the in vitro and in vivo activity of dasatinib against a panel of thyroid cancer cell lines and explore possible mechanisms of action, using various assays and western blotting. Our results showed that dasatinib exhibits prominent cytostatic activity both in vitro and in vivo against thyroid cancer cell lines with RET/PTC rearrangement (BHP2-7) and KRAS mutation (Cal62). Although dasatinib has primarily been described as an ABL/SRCfamily kinase inhibitor, the cytostatic activity observed in the present study is mediated by several off-target effects of dasatinib, some of which have not previously been reported. These effects include a reduction in phospho-FAK, FAK, RAS, Caveolin and SYK protein levels and an increase in β-catenin protein expression, which leads to the induction of senescence, an increase in the adhesiveness of the cells, a decrease in reactive oxygen species level, and changes in the expression profile of molecules involved in cellular adhesion such as integrins. Therefore, we propose that dasatinib is an effective therapeutic agent for certain patients with thyroid cancer, and these candidate patients may be identifiable on the basis of standard genotypic analyses.

H2S protects hippocampal neurons from anoxia-reoxygenation through cAMP-mediated PI3K/Akt/p70S6K cell-survival signaling pathways

The study aims to investigate the effect of hydrogen sulfide (H(2)S) on the phosphatidylinositol 3-kinase (PI3K)/Akt/p70 ribosomal S6 kinase (p70S6K) signal transduction pathway after oxygen glucose deprivation/reoxygenation (OGD/R) in the rat hippocampus. Newborn Wister rats were decapitated under anesthesia, and hippocampal tissue was dissected. Cells were plated at 1.0 × 10(5) cells/mL on polylysine-treated 96-well and 6-well plates. After 7 days in culture, cells were randomly assigned to six groups: control, OGD/R, sodium hydrosulfide (NaHS) following OGD/R, NaHS/triciribine following OGD/R, NaHS/rapamycin following OGD/R, and NaHS/triciribine/rapamycin following OGD/R. Neuronal purity and cell viability were assessed in each group, as well as apoptosis and expression of cyclic adenosine 3', 5'-monophosphate (cAMP), PI3K, Akt, and p70S6K. NaHS enhanced cAMP concentration and expression of PI3K, Akt, and p70S6K. In addition, neuronal viability was increased and apoptotic neuronal numbers decreased (P<0.01). Triciribine inhibited Akt and p70S6K, as well as decreased cell survival and viability compared with the NaHS group (P<0.05 or P<0.01). Rapamycin resulted in decreased p70S6K expression and neuronal viability, as well as increased number of apoptotic neurons compared with the NaHS group (P<0.05 or P<0.01). H(2)S acted via cAMP-mediated PI3K/Akt/p70S6K signal transduction pathways to inhibit hippocampal neuronal apoptosis and protect neurons from OGD/R-induced injury.

Comprehensive assessment of toxic metals in urban and suburban street deposited sediments (SDSs) in the biggest metropolitan area of China

A set of toxic metals, i.e. As, Hg, Pb, Cd, Cu, Zn, Ni and Cr, in urban and suburban SDSs were investigated comparatively in the biggest metropolitan area of China, Shanghai. Results showed that all of the metals except As were accumulated greatly, much higher than background values. Geo-accumulation index indicated that metal contamination in urban SDSs was generally heavier than that in suburban SDSs. Potential ecological risk index demonstrated that overall risks caused by metals were considerable. Cd contributed 52% to the overall risk. Multivariate statistical analysis revealed that in urban SDSs, Zn, Ni, Cd, Pb, Cu and Cr were related to traffic and industry; coal combustion led to elevated levels of Hg; soil parent materials controlled As contents. In suburban SDSs, Pb, Cu, As and Cd largely originated from traffic pollution; Zn, Ni and Cr were associated with industrial contaminants; Hg was mainly from domestic solid waste.

Synergistic antileukemic effects between ABT-869 and chemotherapy involve downregulation of cell cycle-regulated genes and c-Mos-mediated MAPK pathway

Internal tandem duplications (ITDs) of fms-like tyrosine kinase 3 (FLT3) receptor play an important role in the pathogenesis of acute myeloid leukemia (AML) and represent an attractive therapeutic target. ABT-869 has demonstrated potent effects in AML cells with FLT3-ITDs. Here, we provide further evidence that ABT-869 treatment significantly downregulates cyclins D and E but increases the expression of p21 and p27. ABT-869 induces apoptosis through downregulation of Bcl-xL and upregulation of BAK, BID and BAD. We also evaluate the combinations of ABT-869 and chemotherapy. ABT-869 demonstrates significant sequence-dependent synergism with cytarabine and doxorubicin in cell lines and primary leukemia samples. The optimal combination was validated in MV4-11 xenografts. Low-density array analysis revealed the synergistic interaction involved in downregulation of cell cycle and mitogen-activated protein kinase pathway genes. CCND1 and c-Mos were the most significantly inhibited targets on both transcriptional and translational levels. Treatment with short hairpin RNAs targeting either CCND1 or c-Mos further sensitized MV4-11 cells to ABT-869. These findings suggest that specific pathway genes were further targeted by adding chemotherapy and support the rationale of combination therapy. Thus, a clinical trial using sequence-dependent combination therapy with ABT-869 in AML is warranted.

Gene structure and expression of the targeting subunit, RGL, of the muscle-specific glycogen-associated type 1 protein phosphatase, PP1G

The type I phosphatase associated with glycogen, PP1G, plays an important role in glycogen metabolism. PP1G is targeted to glycogen by the R(GL) subunit, which regulates the function of the enzyme. We report the cloning and characterization of the gene as well as the pattern of expression of the R(GL) subunit from mouse. The gene covers more than 37 kb, is composed of four exons and three introns, and codes for a 1089 residue polypeptide with a calculated molecular weight of 121,000. The amino acid sequence has 60% identity with the human and rabbit R(GL). The 5' flanking region of the gene contains a TATA box, c-Myc sites, and a potential cAMP-responsive element. Muscle specific motifs, such as MyoD and MEF-2, were also found. The A-T rich 3'-UTR contained several polyadenylation signals, two associated with poly(A) down-stream consensus motifs. ARE elements, which regulate mRNA stability, were dispersed throughout the 3'-UTR. Northern analysis of poly(A) mRNA from various murine tissues indicates a major transcript of 7.5 kb in skeletal muscle and heart. Western analysis demonstrates that R(GL) protein is present in skeletal and cardiac muscle from mouse, rat, and rabbit but not in L6 myoblasts, L6 myotubes, 3T3 L1 fibroblasts, 3T3 L1 or rat primary adipocytes, confirming that expression of the gene is specific to striated muscle. Analysis of skeletal muscle from rats made diabetic by streptozotocin treatment reveals that the level of R(GL) protein is the same as in control animals, indicating that expression is not regulated by insulin.

M-Ras/R-Ras3, a transforming ras protein regulated by Sos1, GRF1, and p120 Ras GTPase-activating protein, interacts with the putative Ras effector AF6

M-Ras is a Ras-related protein that shares approximately 55% identity with K-Ras and TC21. The M-Ras message was widely expressed but was most predominant in ovary and brain. Similarly to Ha-Ras, expression of mutationally activated M-Ras in NIH 3T3 mouse fibroblasts or C2 myoblasts resulted in cellular transformation or inhibition of differentiation, respectively. M-Ras only weakly activated extracellular signal-regulated kinase 2 (ERK2), but it cooperated with Raf, Rac, and Rho to induce transforming foci in NIH 3T3 cells, suggesting that M-Ras signaled via alternate pathways to these effectors. Although the mitogen-activated protein kinase/ERK kinase inhibitor, PD98059, blocked M-Ras-induced transformation, M-Ras was more effective than an activated mitogen-activated protein kinase/ERK kinase mutant at inducing focus formation. These data indicate that multiple pathways must contribute to M-Ras-induced transformation. M-Ras interacted poorly in a yeast two-hybrid assay with multiple Ras effectors, including c-Raf-1, A-Raf, B-Raf, phosphoinositol-3 kinase delta, RalGDS, and Rin1. Although M-Ras coimmunoprecipitated with AF6, a putative regulator of cell junction formation, overexpression of AF6 did not contribute to fibroblast transformation, suggesting the possibility of novel effector proteins. The M-Ras GTP/GDP cycle was sensitive to the Ras GEFs, Sos1, and GRF1 and to p120 Ras GAP. Together, these findings suggest that while M-Ras is regulated by similar upstream stimuli to Ha-Ras, novel targets may be responsible for its effects on cellular transformation and differentiation.

Electrophoresis of creatine kinase isoforms: a highly sensitive fluorescence scanning method

OBJECTIVE

To develop an agarose electrophoretic method for creatine kinase (CK) isoforms, using highly sensitive fluorescence scanning.

METHODS

A discontinuous buffer system was used. Electrophoresis on agarose gel was performed under constant current and low voltage. CK isoforms were separated within 30 minutes and detected by fluorescence scanning.

RESULTS

There were no significant differences when the activities of CK-MM were between 853.0 U/L and 14.0 U/L and those of CK-MB between 152.0 U/L and 2.4 U/L. The detection limits of stain method for CK-MM and CK-MB isoforms were 36.0 U/L and 12.3 U/L, respectively; while those of fluorescence method were 12.0 U/L and 2.1 U/L. The experimental results showed good precision for CK-MM isoforms, as well for CK-MB isoforms and isoenzymes.

CONCLUSION

An agarose electrophoretic method has been developed to measure CK isoenzymes and isoforms clinically. This method is rapid, simple, sensitive, highly reproducible and inexpensive. It is suitable for general laboratories.

DNA damage in rat brain cells after in vivo exposure to 2450 MHz electromagnetic radiation and various methods of euthanasia

The present study was done to confirm the reported observation that low-intensity acute exposure to 2450 MHz radiation causes DNA single-strand breaks (Lai and Singh, Bioelectromagnetics 16, 207-210, 1995). Male Sprague-Dawley rats weighing approximately 250 g were irradiated with 2450 MHz continuous-wave (CW) microwaves for 2 h at a specific absorption rate of 1.2 W/kg in a cylindrical waveguide system (Guy et al., Radio Sci. 14, 63-74, 1979). There was no associated rise in the core body temperature of the rats. After the irradiation or sham treatments, rats were euthanized by either CO2 asphyxia or decapitation by guillotine (eight pairs of animals per euthanasia group). After euthanasia the brains were removed and immediately immersed in cold Ames medium and the cells of the cerebral cortex and the hippocampus were dissociated separately and subjected to the alkaline comet assay. Irrespective of whether the rats were euthanized by CO2 asphyxia or decapitated by guillotine, no significant differences were observed between either the comet length or the normalized comet moment of cells from either the cerebral cortex or the hippocampus of sham-treated rats and those from the irradiated rats. However, the data for the rats asphyxiated with CO2 showed more intrinsic DNA damage and more experiment-to-experiment variation than did the data for rats euthanized by guillotine. Therefore, the guillotine method of euthanasia is the most appropriate in studies relating to DNA damage. Furthermore, we did not confirm the observation that DNA damage is produced in cells of the rat cerebral cortex or the hippocampus after a 2-h exposure to 2450 MHz CW microwaves or at 4 h after the exposure.

Detection of DNA damage by the alkaline comet assay after exposure to low-dose gamma radiation

The alkaline comet assay as described by Olive et al. (Exp. Cell Res. 198, 259-267, 1992) was used to detect DNA damage in cells exposed to low doses (0-5 cGy) of gamma radiation. Experiments were performed using lymphocytes isolated from whole blood of rats. The comet parameters, normalized comet moment and comet length, described by Kent et al. (Int. J. Radiat. Biol. 67, 655-660, 1995), were used as measurements of DNA damage. It was observed that the alkaline comet assay can detect DNA damage at doses as low as 0.6 cGy. The results of the experiments using low-dose gamma radiation are comparable with published results obtained using the alkaline comet assay according to the method of Singh et al. (Int. J. Radiat. Biol. 66, 23-28, 1994). Based on this observation and analysis of results published previously, we conclude that the version of the alkaline comet assay described by Olive et al. is as sensitive as other modifications of the comet assay reported in literature for the detection of DNA damage in cells exposed to low doses of ionizing radiation.

Enhanced expression of transforming growth factor-beta type I and type II receptors in wound granulation tissue and hypertrophic scar

In the present study we have analyzed and compared, by immunohistochemistry and in situ hybridization, the expression pattern of the R4/ALK5 transforming growth factor (TGF)-beta type I receptor (RI) and the TGF-beta type II receptor (RII) in normal human skin, in wounded skin at various stages during the transition of wound granulation tissue to scar, and in long-persisting post-burn hypertrophic scars. In normal human skin, expression of RI and RII was clearly visible in the epidermis, in epidermal appendages, and in vascular cells, although only a small number of dermal fibroblasts revealed detectable levels of TGF-beta receptor expression. In contrast, granulation tissue fibroblasts showed strong expression of both TGF-beta receptor types, although in normal-healing excisional wounds their density decreased during granulation tissue remodeling. However, in post-burn hypertrophic scars, RI- and RII-overexpressing fibroblasts were found in high densities up to 20 months after injury. From these findings we suggest that the repair process of deep wounds involves the transformation of a subset of fibroblastic cells toward an increased TGF-beta responsiveness and a transient accumulation of these cells at the wound site. In addition, our study provides evidence that excessive scarring is associated with a failure to eliminate TGF-beta receptor-overexpressing fibroblasts during granulation tissue remodeling, which leads to a persistent autocrine, positive feedback loop that results in over-production of matrix proteins and subsequent fibrosis.

Studies on the creatine kinase MM isoforms of normal and Duchenne muscular dystrophic patients

OBJECTIVE

To study the changes of creatine kinase MM (CK-MM) isoforms in Duchenne muscular dystrophy (DMD) patients.

METHODS

Serum samples from 49 DMD patients and 40 control subjects were collected for CK-MM isoforms measurement. CK-MM isoforms were separated within 30 minutes by electrophoresis on agarose gel with a discontinuous buffer system at constant current of 30 mA and low voltage of 200-300 V, then measured by fluorescence scanning.

RESULTS

Significant differences of MM2/MM1 ratio were found between DMD patients and control subjects (P < 0.05) as well as among the three different age groups of DMD patients (P < 0.05).

CONCLUSIONS

CK-MM isoforms may present useful information for the early diagnosis and evaluation of DMD and the ratio of MM2/MM1 can be considered as a specific indicator of the degree of seriousness for DMD patients.