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Biomedical subjects

Bing Yu

Publications and source records attributed to Bing Yu.

At least 73 records · Page 4Linked to original sources
PubMed2004

[Applications of autogenous outer table of the calvarial and mandibular bone in posttraumatic deformities of the nose].

OBJECTIVE: To study the applications of bone grafts from the cranium or mandible in the repair of posttraumatic deformities of the nose. METHODS: From 1997 to 2002, a total of 44 patients, who presented with secondary nose deformity as well as facial fractures, were reconstructed by autogeneous outer table grafts of the calvarial or mandibular bone after facial skeleton reposition. In this series, 32 cases used the calvarial bone, 12 cases used the mandible bone, which was harvested through a coronal incision and an oral approach respectively. RESULTS: The surgical incisions healed primarily in all patients with minimal scar. The facial appearance was greatly improved. No implant infection, extrusion and shift were observed in the postoperative follow-up of 6 months to 2 years. There was not obvious bone resorption, nor donor site morbidity. CONCLUSION: Autogeneous calvarial and mandibular bone was an ideal material of bone graft in reconstruction of severe posttraumatic deformities of the nose. Compared with other autogeneous and alloplastic materials, the outer table of the calvarial and mandibular bone produced less morbidity of the donor site, invisible scar, no rejection and less resorption.

Adolescent↗
PubMed2004

[Effects of MSF on melanocyte adhesion and migration in vitro].

OBJECTIVE: To investigate the Malytea Scurfpea fruit (MSF) on melanocyte adhesion and migration. METHOD: Human epidermal melanocytes were treated with MSF and Ginger respectively, then adhesion to bovine serum fibronectin-coated culture dishes was checked. Control and treated cells were also examined for migration into micropore filters coated with the same protein. RESULT: Compared with control, MSF treated melanocytes were obviously easier to adhere to the dishes and move into the filters in a dose-dependent manner. When the dose of MSF was 200 mg x L(-1), it could not reincrease melanocyte adhesion and migration. At 10 mg x L(-1), under every other concentrations of MSF, there was no marked difference among MSF-treated, Ginger-treated and untreated melanocytes (P < 0.05) when adhesion test were studied. But to migration, even at 10 mg x L(-1) MSF, there was obvious increased migration compared with MSF-untreated or Ginger-treated melanocytes (P < 0.01). CONCLUSION: MSF has effect on melanocyte adhesion and migration, which can explain, in part, the capacity of MSF to modulate melanocyte function in vitiligo lesions.

Cell Adhesion↗
PubMed2004

Effects of endothelin-1 on melanocyte adhesion and migration.

OBJECTIVE: To investigate the effect of endothelin-1 (ET-1) on the adhesion and migration of melanocyte in vitro. METHODS: Human epidermal melanocytes that had been cultured and purified were treated with ET-1 and observed for adhesion to bovine serum fibronectin-coated culture dishes. Stem cell factor (SCF) and ET-1 treated cells were also examined for migration into micropore filters coated with the same protein. RESULTS: Compared with the SCF group, ET-1 treated melanocytes were easier to adhere to the dishes and to be moved into the filters, especially when the concentration was 32 nmol/L. When the concentration of ET-1 was 128 nmol/L or more, it could inhibit the adhesion and migration of melanocyte. At any concentration of ET-1 except at 2 nmol/L, there was a significant difference between ET-1-treated and untreated melanocytes (P < 0.01) when the adhesion test was carried out. However, even at 2 nmol/ L ET-1, there was obviously increased migration compared with those of ET-1 untreated melanocytes and SCF-treated cells (P < 0.01). CONCLUSION: ET-1 may influence the adhesion and migration of melanocyte, which can partly explain the capacity of ET-1 to regulate the melanocyte function in vitiligo lesions.

Cell Adhesion↗
PubMed2004

The inhibitory effects of mouse ICOS-Ig gene-modified mouse dendritic cells on T cells.

The main approach to reduce graft rejection has been focused on the development of immunosuppressive agents at present. Although these strategies have reportedly reduced graft rejection, there has been a reciprocal increase in more severe immunosuppression and lethal infections, as well as severe side effects. Blockade of costimulatory T cell response has been proved as one of useful strategies to reduce graft rejection. Furthermore, it has been shown that infusion of dendritic cells (DCs) with a potent negative regulatory ability for T cells could prolong allograft survival. In this study mouse DCs (mDCs) were transfected with the recombinant plasmid pcDNA3.0 containing mouse inducible costimulator-Ig (mICOS-Ig) cDNA by electroporation. The transient expression of mICOS-Ig in mDC could be detected by ELISA and SDS-PAGE. Mouse ICOS-Ig fusion protein expressed in mDC and mICOS-Ig gene-modified mDC could inhibit lymphocyte proliferation in mixed lymphocyte culture (MLC) in vitro. Furthermore, mICOS-Ig gene-modified mDC could inhibit lymphocyte proliferation in recipient mice. These results suggested that mICOS-Ig gene-modified mDC exerted inhibitory effects on T cells, and might be suitable for treatment or prevention of graft rejection and immunopathologic diseases.

Animals↗
PubMed2003

Grating-assisted demodulation of interferometric optical sensors.

Accurate and dynamic control of the operating point of an interferometric optical sensor to produce the highest sensitivity is crucial in the demodulation of interferometric optical sensors to compensate for manufacturing errors and environmental perturbations. A grating-assisted operating-point tuning system has been designed that uses a diffraction grating and feedback control, functions as a tunable-bandpass optical filter, and can be used as an effective demodulation subsystem in sensor systems based on optical interferometers that use broadband light sources. This demodulation method has no signal-detection bandwidth limit, a high tuning speed, a large tunable range, increased interference fringe contrast, and the potential for absolute optical-path-difference measurement. The achieved 40-nm tuning range, which is limited by the available source spectrum width, 400-nm/s tuning speed, and a step resolution of 0.4 nm, is sufficient for most practical measurements. A significant improvement in signal-to-noise ratio in a fiber Fabry-Perot acoustic-wave sensor system proved that the expected fringe contrast and sensitivity increase.

Journal Article↗
PubMed2003

Fiber Fabry-Perot sensors for detection of partial discharges in power transformers.

A diaphragm-based interferometric fiberoptic sensor that uses a low-coherence light source was designed and tested for on-line detection of the acoustic waves generated by partial discharges inside high-voltage power transformers. The sensor uses a fused-silica diaphragm and a single-mode optical fiber encapsulated in a fused-silica glass tube to form an extrinsic Fabry-Perot interferometer, which is interrogated by low-coherence light. Test results indicate that these fiber optic acoustic sensors are capable of faithfully detecting acoustic signals propagating inside transformer oil with high sensitivity and wide bandwidth.

Journal Article↗
PubMed2003

Comparison between successful and failed sit-to-stand trials of a patient after traumatic brain injury.

OBJECTIVE: To compare the peak whole-body center of mass (COM) velocities and joint angular contributions in successful and unsuccessful sit-to-stand (STS) trials in a subject with traumatic brain injury (TBI). DESIGN: Single-case study. SETTING: Motion research laboratory. PARTICIPANT: A 24-year-old man who was 3.5 years post-TBI. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Peak horizontal and vertical velocities of the whole-body COM and peak angular velocities of the ankle, knee, hip, and shoulder joints. RESULTS: The peak whole-body COM vertical velocity was significantly lower in the unsuccessful STS trials. Angular velocities at the hip, knee, ankle, and shoulder joints in successful trials exceeded those in unsuccessful trials (P<.001). The subject's peak knee extension velocity was the single major predictor of the peak whole-body COM vertical velocity (r(2)=.90). Knee extension angular velocities greater than 3.25 radian/s were associated with successful STS trials. Knee extension angular velocities between 2.75 and 3.25 radian/s were associated with successful rising 50% of the time; the subject had no success in rising when velocities were less than 2.75 radian/s. CONCLUSIONS: For this subject, sit-back failures occurred in STS attempts characterized by peak whole-body COM vertical velocities that were lower than those generated in successful rising trials. These unsuccessful rising attempts were primarily the result of the subject's inability to generate sufficient knee extension angular velocity.

Adult↗
PubMed2003

Effects of functional knee bracing on muscle-firing patterns about the chronic anterior cruciate ligament-deficient knee.

OBJECTIVE: To examine the effects of functional knee bracing on the muscle-firing patterns about the chronic anterior cruciate ligament (ACL)-deficient knee in successful brace users. DESIGN: Cross-sectional comparative clinical trial. SETTING: Motion analysis laboratory. PARTICIPANTS: Ten active individuals with unilateral, isolated, chronic (>18mo postinjury), ACL-deficient knees who subjectively reported improved function with a functional knee bracing. INTERVENTION: Each subject completed 3 single-leg hop maneuvers on their ACL-deficient knee with and without their knee brace while surface electromyographic activity was recorded from the quadriceps, hamstring, and gastrocnemius muscles. MAIN OUTCOME MEASURES: Muscle onset latency. RESULTS: Brace use significantly delayed the average onset of vastus lateralis activation before landing (123+/-47ms vs 109+/-30ms, P<.001), though significant interindividual variations existed. Bracing significantly altered the onset latency in 1 or more muscles in 9 of 10 subjects. In 4 subjects, a favorable change in the firing pattern was seen, whereas only 1 subject exhibited an unfavorable change. Without bracing, 5 of the 10 subjects fired the hamstrings or gastrocnemius muscles first; with bracing, 7 of 10 fired these muscles first. CONCLUSIONS: Brace use in this population did not consistently result in more favorable muscle firing patterns during the single-leg hop maneuver. Interindividual responses to brace use indicate the need for further research to investigate the multiple strategies that may exist to stabilize the ACL-deficient knee. In the meantime, functional knee brace use among ACL-deficient patients remains empirical.

Adolescent↗
PubMed2003

Theoretical study of the effect of ball properties on impact force in soccer heading.

PURPOSE: The objective of this study was to theoretically model, based on the Hertz contact theory, the impact force and contact time, as well as the linear and angular head accelerations during heading in children using two neck stiffness conditions (infinite and negligible stiffness). METHODS: The following mathematical model inputs were obtained: elastic modulus and mass of size three, four, and five balls at inflation pressures of 10, 12, and 14 psi, head modulus, head mass, head length, head and trunk moment of inertia, and the precontact ball velocity. The model outputs consisted of linear and angular head acceleration, impact force, contact time between the ball and head, and head impact criteria (HIC) all at the point of impact. Head mass and length were obtained as a percentage of body weight and height, respectively, based on age. RESULTS: With an increase in head mass, there is a decrease in the linear and angular head acceleration. With an increase in ball size, for the same head mass, there is an increase in the contact time between the head and the ball. Changing ball inflation pressure has little effect on the impact characteristics. Infinite neck stiffness decreased linear and angular head acceleration and HIC. CONCLUSION: Head mass and ball size have an effect on linear and angular head acceleration and contact time, respectively, whereas ball inflation pressure has a minimal effect on the impact characteristics. These results indicate that children should be restricted to using the appropriate ball for their age. Smaller head size within an age group is an underemphasized though important identifier of a player's injury risk.

Acceleration↗
PubMed2003

[Intro-extro cranial approach treat serious post fronto-orbital fracture deformities].

OBJECTIVE: To explore the method of treating serious secondary fronto-orbital fracture deformities through intro-extra cranial approach. METHODS: The fronto-orbital fracture was divided into two types according to whether there were any large scale fronto-orbital bone defects: type I: Large scale fronto-orbital bone defect; type II: Concave fronto-orbital fracture deformity without large scale bone defect. Both types were treated through intro-extra cranial approach to expose the fracture site. For type I deformity, the bone defects were repaired and reconstructed with outer table of cranial bone and artificial bone. For type II, the deformity was repaired by osteotomy, bone reposition and internal rigid fixation. RESULTS: 18 cases were treated from June 1998 to October 2000, include type I, 12 cases, and type II, 6 cases. All the patients recovered well and the post-operative appearance were greatly improved. CONCLUSIONS: Intro-extra cranial approach can expose the fractured site better than the simple extrocranio approach, and make the operation more easily done. Combined with the technique of cranio maxillo facial surgery, the treatment can be more complete and the results can be more satisfactory.

Fracture Fixation, Internal↗
PubMed2002

Functional and spectroscopic studies of a familial hypertrophic cardiomyopathy mutation in Motif X of cardiac myosin binding protein-C.

Familial hypertrophic cardiomyopathy is an autosomal dominant genetic disorder caused by mutations in cardiac sarcomeric proteins. One such mutation is a six amino acid duplication of residues 1248-1253 in the C-terminal immunoglobulin domain of cardiac myosin binding protein-C, referred to as Motif X. Motif X binds the myosin rod and titin. Here we investigate the structural and functional alteration in the mutant Motif X protein to understand how sarcomeric dysfunction may occur. The cDNA encoding Motif X was cloned, mutated and expressed as wild-type and mutant proteins in a bacterial expression system. Circular dichroism spectroscopy confirmed that the normal and mutant Motif X exhibited a high beta-content, as predicted for immunoglobulin domains. Thermal denaturation curves showed that Motif X unfolded with at least two structural transitions, with the first transition occurring at 63 degrees C in the wild-type but at 40 degrees C in the mutant, consistent with the mutant being structurally less stable. Sedimentation binding studies with synthetic myosin filaments revealed no significant difference in binding to myosin between the wild-type and the mutant Motif X. Molecular modeling of this duplication mutation onto an homologous IgI structure (telokin) revealed that the duplicated residues lie within the F strand of the immunoglobulin fold, on a surface of Motif X distant from residues previously implicated in myosin binding. Taken together, these data suggest that the Motif X mutation may interfere with other, as yet unidentified, functional interactions.

Amino Acid Motifs↗
PubMed2002

A kinetic analysis of discus-throwing techniques.

The purposes of this study were to investigate (1) the relationships between official distance and selected ground reaction measures during discus throwing; and (2) the relationships between selected ground reactions and selected lower extremity joint kinetics. Three high-speed video cameras and three force plates were used to collect three-dimensional videographic and force plate data in this study. An inverse dynamic model was used to determine the lower extremity kinetics. Multiple regression analyses were conducted to determine relationships of the selected kinematic and kinetic measures with the official distance. Official distance was significantly correlated with ground reaction forces on the left foot during the first single-support phase, on the right foot during the second single-support phase and delivery phase, and on the left foot during the delivery phase. Also, the right-hip extension and internal rotation moments and left-knee extension moment during the delivery phase were significantly correlated with official distance. These results suggest that discus throwers should drive vigorously forward during the first single-support phase and increase the landing impact force on the right foot after flight. Also they should increase forward and rightward ground reaction force on the right foot and backward and vertical force on the left foot by powerful right-hip extension and internal rotation and left-knee extension during the delivery phase. These results provide critical information regarding the training of discus-throwing techniques, and the direction of future biomechanical studies on this event.

Biomechanical Phenomena↗
PubMed2002

[Correction of prominent malar complex by L-type osteotomy].

OBJECTIVE: To present a new method for correction of prominent malar complex by L-shaped osteotomy through an intraoral incision. METHODS: Based on the anatomical characteristics of the malar complex, we designed a new L-shaped osteotomy for malar eminence reduction. The procedure includes oblique incision of the upper part of the mala, vertical incision of the anterior part of the mala and "greenstick" fracture of the zygomatic arches. According to the severity of malar prominence, we resect part of the anterior-inferior part of the mala and lower the malar complex. RESULTS: This method was used in 39 patients with prominent malar complex. Of them, 32 were symmetrical and 7 were unsymmetrical. All the patients obtained good results. CONCLUSION: L-shaped osteotomy for correction of prominent malar complex is a relatively ideal surgical method with the advantages of simpler manipulation, fewer complications, better result, and ensuring the intactness of the structural characteristics of the malar complex.

Adult↗
PubMed2002

[The surgical management of late complex posttraumatic enophthalmos].

OBJECTIVE: To study the surgical management of late complex posttraumatic enophthalmos. METHOD: According to the X-ray film and CT examination, the displaced orbital bone fragments was repositioned after osteotomy and rigid fixed by mini-plate and screws, then the orbital walls were repaired. RESULT: From July 1996 to June 2001, 42 cases were treated and the enophthalmos were obviously corrected or improved. CONCLUSION: The late complex posttraumatic enophthalmos can be corrected or obviously improved through reconstruction of the normal shape and volume by the reduction of displaced bone fragments and precise orbit wall repair.

Adolescent↗
PubMedDate not supplied

Molecular characterization of pig ST8Sia IV--a critical gene for the formation of neural cell adhesion molecule and its response to sialic acid supplement in piglets.

ST8Sia IV (polysialyltransferase IV gene) encodes a key enzyme that is required for polysialic acid synthesis. Polysialic acid is a component of the neural cell adhesion molecule and is necessary for synaptic plasticity of neural cells. We characterized 5.3 kb of pig ST8Sia IV cDNA and determined its expression profile in different organs. In hippocampus, ST8Sia IV mRNA levels were increased approximately 4.5-fold in piglets with sialic acid as a milk supplement, which suggested that exogenous sialic acid is a conditionally essential nutrient for early brain development. Extensive analyses were also performed among its orthologs from human, mouse, rat, chicken, frog and zebrafish. Our results supported that the piglet is a better animal model than other nonprimate species in the studies of ST8Sia IV related metabolism and nutrition in human infants. This pig cDNA provides a basis for uncovering the roles of ST8Sia IV during piglet development and maturation.

Amino Acid Sequence↗
PubMedDate not supplied

The repeatability of scapular rotations across three planes of humeral elevation.

Measurement of scapular kinematics is an important component in the assessment of shoulder function; however, repeatability of these measurements has not been established. The purpose of this study, therefore, was to determine the repeatability of scapular rotation measures for different humeral elevation planes between trials, sessions, and days. Three-dimensional scapular rotations were collected using an electromagnetic tracking system in three planes of humeral elevation. Coefficient of multiple correlation (CMC) values were calculated between trials, sessions, and days for curves of scapular rotations. CMC values were compared with repeated measures analysis of variance (ANOVAs) and Tukey's post-hoc procedures. Tests of simple main effects were performed for significant interaction effects. Our results suggest that scapular rotation measures are repeatable between trials within the same testing session, but less repeatable between testing sessions and days. Sagittal plane elevation consistently yielded the highest CMC values for all scapular rotations. These results suggest sagittal plane elevation should be considered to evaluate differences in scapular rotations.

Adult↗
PubMedDate not supplied

A comparison of knee kinetics between male and female recreational athletes in stop-jump tasks.

We compared the knee kinetics of 10 male and 10 female recreational athletes (aged 19 to 25 years) performing forward, vertical, and backward stop-jump tasks. Three-dimensional videography and force plate data were used to record the subjects' performance of the three stop-jump tasks, and an inverse dynamic procedure was used to estimate the knee joint resultant forces and moments. Women exhibited greater proximal anterior shear force than did men during the landing phase. All subjects exhibited greater proximal tibia anterior shear force during the landing phase of the backward stop-jump task than during the other two stop-jump tasks. Women also exhibited greater knee extension and valgus moments than did men during the landing phase of each stop-jump task. Men exhibited greater proximal tibia anterior shear force than did women during the takeoff phase of vertical and backward stop-jump tasks. These results indicate that female recreational athletes may have altered motor control strategies that result in knee positions in which anterior cruciate ligament injuries may occur. The landing phase was more stressful for the anterior cruciate ligament of both women and men than the takeoff phase in all stop-jump tasks. Technical training for female athletes may need to be focused on reducing the peak proximal tibia anterior shear force in stop-jump tasks. Further studies are needed to determine the factors associated with the increased peak proximal tibia anterior shear force in female recreational athletes.

Adult↗