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Biomedical subjects

Bing Shi

Publications and source records attributed to Bing Shi.

At least 19 recordsLinked to original sources
PubMed2007

Free energy profiles for monomer capture in Grubbs- and SHOP-type olefin polymerization catalysts: a constraint ab initio molecular dynamics study.

Density functional theory together with Car-Parrinello ab initio molecular dynamics simulation has been used to investigate the free energy profiles (FEP) of monomer capture in Grubbs- and SHOP-type olefin polymerization catalysts. The FEPs along the reaction coordinates at 300 K were determined directly by a point wise thermodynamic integration technique. Comparison between potential energy profile (PEP) and the FEP has been made. The results show that, for both catalysts, the PEP for the monomer ethylene uptake by the metal center is a typical Morse curve without energy barrier. However, a small barrier (1.8 kcal/mol for Grubbs catalyst and 2.4 kcal/mol for SHOP catalyst) exists on the FEP. The pi complexation energy on the FES at 300 K is higher by 10-12 kcal/mol over that on the PES. The differences between FES and PES are due to entropy contribution. Slow growth simulations on the ethylene capture process show that the ethylene attacks the metal center by an asynchronous mode. This indicates that the forming of the pi-bonding between the metal and ethylene is initiated by electrophilic attack of the metal to one of the ethylene carbons.

Alkenes↗
PubMed2006

Survey of the patients with cleft lip and palate in China who were funded for surgery by the Smile Train Program from 2000 to 2002.

BACKGROUND: Cleft lip (CL) and cleft palate (CP) are two of the most frequent congenital malformations. Many epidemiologic studies on this deformity have been conducted worldwide, often producing inconsistent results. This study assessed epidemiology and some genetic aspects of cleft lip and palate in a Chinese sample from the Smile Train Program and to compare with other methodologically sound surveys. METHODS: The general information, family history, classification of cleft and associated malformations of 8000 CL and CP surgery patients were analyzed. RESULTS: Of the 8000 cases, 7812 had complete data. The distribution of cleft types is 17.04% with CP, 23.39% with CL and 59.58% with cleft lip and palate (CLP). Unilateral clefts were more common than bilateral, with unilateral to bilateral ratios being 10.4:1 for CL, and 3.42:1 for CLP. The overall male:female ratio was 2.01:1. Left sided defects were more common than right sided regardless of sex, 1.90:1 for CL and 1.96:1 for CLP. CLP and CL were more common in males than in females with sex ratios (SR) of 2.88:1 and 1.85:1 respectively, whereas CP was more common in females with SR of 0.76:1. Associated malformations (2.89%), involved 29 CP cases, 41 CL and 156 CLP. The frequency of associated malformations in CLP (3.35%) was higher than CL (2.24%) and CP (2.22%) (P < 0.05). Patients with CP or CLP were born less often in the winter than in the summer (P < 0.05). A history of family members having clefts occurred in 6.84% of patients. The proportion of CLP cases (7.56%) was significantly higher than that of CL cases (5.64%) (P < 0.05). CONCLUSIONS: The different types of clefts appeared in the highest proportion in CLP and lowest proportion in CP. Males are more common with CL and CLP and less common with CP. These characteristics are the same as those of other Chinese surveys but different from some European reports.

China↗
PubMed2006

Effects of lip repair on maxillary growth and facial soft tissue development in patients with a complete unilateral cleft of lip, alveolus and palate.

PURPOSE: To examine the relationship between lip repair and inhibition of maxillary growth, and to investigate the characteristics of upper lip in patients with complete unilateral clefts of lip, alveolus and palate. MATERIAL AND METHODS: Lateral cephalometric radiographs and photographs (anterior-posterior and profile) were taken for 3 groups of patients: (1) 35 complete unilateral cleft lip, alveolus and palate cases in whom only a labioplasty was performed as infants; (2) 47 cases who had both lip and palate repaired; and (3) 37 non-cleft peers as controls. RESULTS: There was maxillary retrusion in groups (1) and (2). Surface area and height of the upper lip was reduced in both these groups when compared with the normal controls. CONCLUSION: Lip repair is a most important factor in the restraint of maxillary growth in patients with complete unilateral clefts of lip, alveolus and palate. And height and projection of the upper lip are reduced following lip repair.

Adolescent↗
PubMed2006

Folic acid rivals methylenetetrahydrofolate reductase (MTHFR) gene-silencing effect on MEPM cell proliferation and apoptosis.

It's clear that environmental factors play a role in the aetiology of orofacial clefting (OFC) and an important area of future research will be to unravel interactions that occur between candidate genes and environmental factors during early development of the embryo. Periconceptional folic acid supplementation may reduce the risk of OFC. Polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene reduce availability of 5-methylenetetrahydrofolate, the predominant circulating form of folic acid. To determine the effect of MTHFR gene mutation on murine embryonic palatal mesenchymal (MEPM) cells and the interaction with folic acid supplement, we used RNAi study in the primary cultures of MEPM cells. The cells of MTHFR gene silencing grew slower and the apoptosis cell number was more than the cells of control. Supplement with 20 microg/ml folic acid was the best to preventing teratogenic effect of MTHFR gene silencing. By flow cytometry analysis of cell cycle, results were shown that the MEPM cells were retarded in G(0)/G(1) after MTHFR gene silencing. While using 20 microg/ml folic acid supplements could make cell transit the G(1)/S restriction point and the cells growth was close to normal level.

Animals↗
PubMed2006

Analysis of velopharyngeal morphology in adults with velopharyngeal incompetence after surgery of a cleft palate.

This study analyzed the relationship of velopharyngeal morphology and velopharyngeal function among 13 adults with velopharyngeal incompetence (VPI), 14 adults with velopharyngeal competence (VPC) after primary surgical treatment of cleft palate, and 20 noncleft adults. The measurements included velar length, pharyngeal depth, pharyngeal height, and the need ratio of pharyngeal depth to velar length. In addition, the cranial base, cervical vertebrae, posterior nasal spine, and also the position of the posterior pharyngeal wall (PPW) in the pharyngeal triangle were analyzed. All data were subjected to the Student t test of statistical significance. The results showed that the VPI group had normal pharyngeal depth and a significantly shorter velar length, resulting in a greater depth/length ratio than those of the VPC group and normal control subjects. The position of PPW in the pharyngeal triangle was located significantly more superior in the VPI group compared with the VPC group and normal control subjects. Measurements of the anteroposterior and the vertical dimensions in the regions of the cranial base and cervical vertebrae revealed no significant difference among the 3 groups. According to this study, the velopharyngeal morphology of adults with VPI is characterized by a shorter palate, greater need ratio, slightly counterclockwise-rotated pharyngeal triangle, and superiorly positioned PPW.

Adolescent↗
PubMed2006

Clinical and epidemiologic studies of nonsyndromic cleft lip and palate in china: analysis of 4268 cases.

The aim of our study was to review clinical and epidemiologic characteristic of the nonsyndromic cleft lip and cleft palate over a period of 10 years at West China Stomatological Hospital, Sichuan University. Four thousand two hundred sixty-eight nonsyndromic cleft lip and cleft palate cases were retrospectively analyzed according to the following variables: general information, cleft type, maternal age, familial history, as well as associated malformations, et al. In these cases, 1075 of which were cleft lip, 1985 were cleft lip with cleft palate; 1208 were isolated cleft palate. There were more men than women in the cleft lip and cleft lip with cleft palate group, while there were more women than men in the isolated cleft palate group. There were significantly more unilateral cleft lip cases than cleft lip on both sides; the cases of cleft lip on the left side were more than that of cleft lip on the right side. The cases with inherited history accounted for 6.68% of all the cases. Most infection cases occurred among the deleterious factors and the complications experienced during the first 3 months after the pregnancy. In all of the 14 twin cases, only 1 of the babies was affected. There were totally 152 cases with other associated malformations. Patients with cleft lip born in November to January were less than those born in the other three quarters of the year. Patients of A blood group composed a higher proportion than the control group. Our data may provide references for appropriate resource use, cleft lip and cleft palate prevention programs, and counseling programs with China-specific data.

Adult↗
PubMed2006

Comparative study of maxillary growth and occlusal outcome after autogenous rib grafting in complete cleft palate defect.

Cleft palate is a congenital deformity with soft tissue and hard tissue defects. Normal cleft palate repairing surgery only repairs soft tissue defects, whereas bone defects in the hard palate still exist. Therefore, we conducted this study in beagles to observe the influence of bone grafting at primary surgery on craniofacial growth and occlusal relationships in individuals with complete cleft palate and to provide experimental evidence for optimal surgical procedures for cleft palate. Using 60 beagle puppies as subjects, we tested the effects of bone grafting in surgically induced palatal defect. The animals were randomly and equally divided into four groups: (1) unoperated controls; (2) surgically induced unilateral cleft palate, not repaired; (3) two-flap palatoplasty used to close the soft defect of the surgically induced cleft palate; (4) autogenous bone (a piece of rib bone) implanted into the palatal defect before two-flap palatoplasty was performed.Cephalometric roentgenography and plaster casts of the maxillary were taken preoperatively and every 4 weeks after surgery. Sixty metric cranial variables were measured directly from the cleaned skulls after the animals were killed the 34th week postoperatively. The measurement results indicated that bone grafting may reduce the disturbance of maxillary growth caused by the cleft palate and the denuded bone, but it may cause other maxillary deformities. This finding suggests that surgeons should be careful in choosing the method of primary bone grafting in repairing complete cleft palate.

Animals↗
PubMed2006

[Separation and culture of mouse embryonic palatal mesenchymal cells in vitro].

OBJECTIVE: To modify the operation of dissecting embryonic palatal shelves and purify the mouse embryonic palatal mesenchymal (EPM) cells in primary culture. METHODS: The embryonic palatal shelves were dissected using a surgical microscope by modified operation. Then the embryonic palatal shelves were incubated with Dispase and the isolated EPM cells were cultured. Immunofluorescence technique was used to identify the characteristics of cells. RESULTS: Embryonic palatal shelves could be dissected accurately and easily with a modified operation. The purified EPM cells contained scarcely epithelial cells. EPM cells were anti-HNK-1, S-100, vimentin positive and anti-CK negative. CONCLUSION: A modified method for dissecting embryonic palatal shelves and purifying the EPM cells of primary culture was established.

Animals↗
PubMed2006

[Mechanical force distribution on cleft maxillary finite-element models after alveolar and hard palate bone graft].

OBJECTIVE: To investigate the biomechanical force distribution of three different cleft maxillary finite-element models pre- and post-bone graft with specified load to certain area of the models. METHODS: Developing a cleft palate bony model from a 15-year cleft palate male CT scan DICOM data and generating alveolar bone-grafted, alveolopalatal bone-grafted cleft maxillary finite-element model was set up through gluing the graft model. Also the pre-grafted model as compared, vector lip force on the anterior and anteriolateral face of the alveolar ridge was applied, and studied the press distribution properties and localized area. RESULTS: The press principal spread along the alveolar ridge and focused on anterior wall of maxillary prior to graft. But the press tended to be evenly distributed after bone grafted, whether alveolar or/and hard palate bone grafted. The grafted bone could resisted the medially deformation of alveolar crest and decreased the shear press to the nasal base bony structure. The map showed no significant differences along with alveolar or/and hard palate bone graft. CONCLUSION: The postoperative lip pressure plays an important role for the deformation and deviation of alveolar ridge. Alveolar bone graft could even the distribution of the stresses and should be emphasized. But the grafted bony palatal appears superior to but no significant mapping and anti-deformation difference with alveolar bone graft.

Alveolar Process↗
PubMed2006

[Preliminary study on self-concept psychological feature of cleft lip and palate adolescents].

OBJECTIVE: To obtain the self-concept psychological feature of cleft lip and palate (CLP) adolescents further and accurately, and offer reasons for timely and pointed psychological intervention. METHODS: Based on the procedure and criteria of development of psychological questionnaire, a psychological questionnaire for CLP adolescents was designed. 93 CLP and 88 healthy adolescents were studied by using it and their half-quantified score raging 0-9 were analyzed statistically. RESULTS: (1) There was no statistical difference between CLP and normal adolescents, scored 5.91 and 5.66 respectively, which demonstrated that the self-concept of CLP adolescents was at a normal level without obvious passive tendency. (2) There was no significant difference between genders, but boys were more extroversion while girls did better on being unyielding and releasing strain. (3) CLP adolescents had a higher ability of psychological regulation and could face failure more bravely. CLP patients were in a tendency of protective behavior inhibition, companied less, and maximized delight mood unconsciously to decrease harm from enviroment. (4) CLP adolescents had a good parentage. (5) A majority of patients had low expectation of life-quality. (6) Much of CLP patients considered that speech was more important than appearance. CONCLUSION: Self-concept of CLP adolescents have normal self-concept and do better in psychological regulation and dependence than normal ones.

Adolescent↗
PubMed2006

[Individual repair technique of microform cleft lip: state of art].

OBJECTIVE: To explore an technique to repair the microform cleft lip (MCL). METHODS: The individual method was used to repair the MCL, a contrastive research was carried to analyzed the result. RESULTS: It was found that the form of the cupid's bow was good, and the configure of the upper lip was reconstructed. The deficit of the orbicularis muscle was overcame and the function was satisfying by this procedure. Symmetry was recovered. CONCLUSIONS: Individual technique is an available method to repair the microform cleft lip. Furthermore, this technique is also promising to repair the other kinds of cleft lip.

Cleft Lip↗
PubMed2006

[Study on repair approach of bilateral cleft lips and nose deformity].

OBJECTIVE: To detect the operative technique and aesthetic problem of reconstruction to deformity of bilateral cleft lip. METHODS: From March 2003 to December 2004, 26 patients with bilateral cleft lip were treated, aged 10 months to 11 years. Of 26 patients, there were 13 bilateral complete cleft lip and palate, 9 bilateral incomplete cleft lip and 4 mixed cleft lip with unilateral complete cleft palate. The chief design principle was keeping the length of prolabium. During operation, sufficient dissociation was made in the base of the ala base and orbicularis oris muscle to reconstruct these structures. The circle suture was made for the bilateral orbicularis oris muscle. The shape of vermilion was achieved by lateral red lip muscle flap and simultaneous simple rhinoplasty was performed. RESULTS: Primary healing of the incisions was achieved in all cases. After the 10 days-3 months follow-up, the results were satisfactory in the width and chubbiness of the nose bottom, the shapes of nostril and Cuspid's bow were good without whistle deformity. The appearance of upper lip was good in either dynamic or static state. CONCLUSION: Excellent shapes and function of the nose and lip, and opportunity for two-stage repair could be obtained with this method, which being believed important methods for the primary repair of bilateral cleft lip.

Child↗
PubMed2006

[The mechanical force analysis of cleft maxillary three dimensional finite element models after alveolar bone graft].

To investigate the biomechanical influences on two different cleft maxillary 3D finite element models pre- and post-alveolar bone graft, we developed a cleft palate bony model from a 17 year cleft palate male CT scan data and built an alveolar bone-grafted cleft maxillary 3D finite element model through gluing the graft model. Apply vector lip force on the anterior face of the models. Study the press (including S3 principal, S1 principal, von Mises and shear) distribution properties and localized area. The results suggested that the press principal spreads along the alveolar ridge and formed several focused areas. After bone grafted, the shear stress tends to be evenly. The grafted alveolar could resist the medially deformation of alveolar crest and the shear stress to the nasal base bony structure. The conclusions from results demonstrated that the deformation of alveolar ridge is possibly due to the lip pressure after the lip repair. The shear stress along the alveolar ridge could cause the severity of the dentition. The grafted bony structure could even the shear stress distribution evenly other than the distribution properties.

Adolescent↗
PubMed2005

[Observing the distribution of Annexin I and cPLA2 in the palatal process of mice by immunohistochemical staining].

OBJECTIVE: To observe the distribution of Annexin I and cytosolic phospholipose A2 (cPLA2) in the palatal process of dexamethasome teratogenerated mice. METHODS: Cutting along the coronary plane of the heads of fetal mice to obtain palate in the 14th, 15th, 16th day of gestation by 10-week-old in-bred mice. The distribution of Annexin I and cPLA2 was checked by immunohistochemical staining. RESULTS: During the fusing of the palatal processes, the staining of Annexin I and cPLA2 was positive in the epithelial and mesenchymal cells of the palatal process, and the intensity of staining changed with time. CONCLUSION: Annexin I and cPLA2 can modulate the development of fetal palate to some extent, and they may be important mediators in the development of cleft palate induced by dexamethasone.

Animals↗
PubMed2005

[Influence of dexamethasone on fusion of embryonic palatal medial edge epithelium in mouse palatal shelves in vitro].

OBJECTIVE: To study the effect of dexamethasone on the differentiation and proliferation of type A mouse palatal medial edge epithelial cells when there is type A mouse embryonic palatal mesenchymal cells. METHODS: The mouse palatal shelves were harvested from a female mouse of gestation day 14 by microsurgical dissection and cultured in vitro. The differentiation was investigated through microscope and transmission electron microscope under condition of the palatal shelves fusion. RESULTS: Dexamethasone promoted the palatal medial edge epithelium differentiated into squamause epithelium and affected normal development and obstructed the fusion of mouse palatal shelves. CONCLUSION: The results of histological observation indicate that dexamethasone promotes the proliferation of palatal meseuchymal cells and inhibits the normal differentiation of palatal medial edge epithelial cells, which results in cleft palate.

Animals↗
PubMed2005

[Recombinant adeno-associated viral vector 2-mediated gene transfer of VEGF165 improved porcine chronic myocardial ischemia].

OBJECTIVE: Vectors commonly used for therapeutic angiogenesis such as adenovirus and plasmid had their own limitations. Adenovirus-associated virus (AAV) is a relatively new but probably more ideal vector as it is safe and efficient. We will study the efficiency of recombinant AAV-2 mediated vascular endothelial growth factor165 gene transfer in inducing angiogenesis and arteriogenesis, in improving blood flow and myocardium function in a porcine chronic myocardial ischemic model. METHODS: Chinese experimental minipigs underwent placement of a left circumflex artery aneroid constrictor. Five weeks later, electrocardiogram, coronary angiography and magnetic resonance imaging were performed to confirm occlusion of LCX or ischemia of myocardium in LCX territory. Coronary blood flow, myocardium perfusion and left ventricular wall function were also evaluated. Then the animals were randomized to treatment with rAAV2-VEGF(165) (1 x 10(12) virus genome) or administration of PBS, both by direct myocardial injection. Three and six months after therapy, the animals were evaluated with regard to expression of VEGF(165) Capillary density and arteriole density of the ischemic myocardium, coronary angiography, myocardial perfusion and left ventricular function were also assessed six months after therapy. RESULTS: Five weeks after aneroid occluder implantation, all the animals demonstrated complete or nearly complete occlusion of LCX and perfusion deficiency in LCX territory. Three months after therapy, expression of VEGF(165) mRNA and protein were higher in the VEGF than control group. The difference between the two groups diminished after six months. There was significant increase in capillary density (1404.06 +/- 250.48/mm(2) vs 976.88 +/- 344.79/mm(2), P < 0.05) and arteriole density (167.81 +/- 36.29/mm(2) vs 116.56 +/- 34.48/mm(2), P < 0.05) in VEGF group compared with control. Comparison of myocardial perfusion demonstrated marked differences between the two groups with significant improvement in animals treated with rAAV2-VEGF(165). No significant improvement in left ventricular function was seen in either the VEGF or control group. CONCLUSIONS: Transmyocardial delivery of rAAV2-VEGF(165) resulted in VEGF gene expression for at least three months and stimulated angiogenesis and arteriogenesis in porcine model of chronic myocardial ischemia. Myocardial perfusion was also improved after VEGF gene delivery.

Adenoviridae↗
PubMed2005

[Different histological changes of hard palates in rats with different areas of denudated bone].

PURPOSE: To explore the relationship between the histological changes of the denudated bone in the hard palate of rats and its sizes. METHODS: Sixteen three-week-old SD male rats were randomly divided into 4 groups (a control group and 3 experimental groups). In the three experimental groups, one and two and three quarters of the bilateral palatal mucoperiosteum were excised respectively. One animal in each group was sacrificed every two weeks and the histological differences were observed. RESULTS: Different histological changes were found among the groups. When the denuded part was over half of the palate, tight connections between scar tissues and both the palatal bone and the periodontal fibers were observed. Many necrotic bone tissues appeared in the mid-palate if more than three quarters of areas were exposed. CONCLUSION: Different sizes of denuded bone may lead to different histological appearances. Structures and tissues change more when denuded part of the bone is larger.

Animals↗