Designing customized temporomandibular fossa prosthesis based on envelope surface of condyle movement: validation via in silico musculoskeletal simulation.

Objective: This study presents an innovative articular fossa prosthesis generated by the envelope surface of condyle movement, and compares its mandible movements, muscle activities, and joint reaction forces with two temporomandibular joint (TMJ) prostheses using multibody musculoskeletal simulation. Methods: A healthy 23-year-old female was recruited for this study. Cone-beam computed tomographic (CBCT) was performed to reconstruct the mandibular bone geometry. A customized TMJ fossa prosthesis was designed based on the subject-specific envelope surface of condyle movement (ESCM). Mandibular kinematics and jaw-closing muscle electromyography (EMG) were simultaneously recorded during maximum jaw opening-closing movements. To validate our prosthesis design, a mandibular musculoskeletal model was established using flexible multibody dynamics and the obtained kinematics and EMG data. The Biomet fossa prosthesis and the ellipsoidal fossa prosthesis designed by imitating the lower limb prostheses were used for comparison. Simulations were performed to analyze the effects of different fossa prostheses on jaw opening-closing motions, mandibular muscle activation, and contact forces. Results: The maximum opening displacement for the envelope-based fossa prosthesis was greater than those for Biomet and ellipsoidal prostheses (36 mm, 35 mm, and 33 mm, respectively). The mandibular musculoskeletal model with ellipsoidal prosthesis led to dislocation near maximal jaw opening. Compared to Biomet, the envelope-based fossa reduced the digastric and lateral pterygoid activation at maximal jaw opening. It also reduced the maximal resistance to condylar sliding on the intact side by 63.2 N. Conclusion: A customized TMJ fossa prosthesis was successfully developed using the ESCM concept. Our study of musculoskeletal multibody modeling has highlighted its advantages and potential. The artificial fossa design successfully achieved a wider condylar range of motion. It also reduced the activation of jaw opening muscles on the affected side and resistance on the intact side. This study showed that an ESCM-based approach may be useful for optimizing TMJ fossa prostheses design.

Comparative Study of Temporomandibular Articular Fossa Bone Surface and the Envelope Surface of the Condyle Movement.

OBJECTIVE: To investigate the differences between temporomandibular articular fossa bone surface and the envelope surface of the mandibular condyle movement. METHODS: Thirty-four healthy adults underwent skull base and mandible scans using CBCT and performed mandibular border movement using the mandibular movement recording system. Landmarks of the fossa and tubercle were indicated and distance and angle parameters were measured on the 3D models reconstructed from the CBCT. The condyle movement envelope surfaces were formed according to models reconstructed from CBCT and the mandibular movement trajectory using computer simulation. The highest and lowest points of the envelope surface were indicated to create parameters. The data were analysed using a paired t test in SPSS (version 24.0, IBM, Armonk, NY, USA). RESULTS: The mandibular fossa bone surface was statistically different to the envelope surface for the height of the first peak of the envelope surface (3.280 ± 1.319 mm) and depth of the mandibular fossa (6.338 ± 2.389 mm) (the ratio was 51.75%), the height of the second peak of the envelope surface (1.463 ± 0.745 mm) and the height of the tubercle (2.000 ± 0.968 mm) (the ratio was 73.15%), and the downwards angle of the envelope surface (25.933 ± 7.539 degrees) and the posterior slope angle of the articular tubercle (35.059 ± 5.224 degrees) (the ratio was 73.97%). CONCLUSION: The downwards angle of the envelope surface was statistically significantly smaller than the posterior slope angle of the articular tubercle, suggesting that the condyle movement is flatter than the mandibular fossa bone surface.

PGF2α stimulates the 10-pS Cl- channel and thiazide-sensitive Na+-Cl- cotransporter in the distal convoluted tubule.

We used patch-clamp and Western blot analysis to test whether PGF2α stimulates the basolateral 10-pS Cl- channel and thiazide-sensitive Na+-Cl- cotransporter (NCC) in the distal convoluted tubule (DCT) via a prostaglandin F receptor (FP-R). Single channel and whole cell recordings demonstrated that PGF2α stimulated the 10-pS Cl- channel in the DCT. The stimulatory effect of PGF2α on the Cl- channel was mimicked by a FP-R agonist, latanoprost, but was abrogated by blocking FP-R with AL8810. Also, the effect of PGF2α on the Cl- channel in the DCT was recapitulated by stimulating PKC but was blocked by inhibiting PKC. Furthermore, inhibition of p38 MAPK but not ERK blocked the effect of PGF2α on the 10-pS Cl- channel. Inhibition of NADPH oxidase also abrogated the stimulatory effect of PGF2α on the 10-pS Cl- channel, while the addition of 10 µM H2O2 mimicked the stimulatory effect of PGF2α on the 10-pS Cl- channel. Moreover, superoxide-related species may mediate the stimulatory effect of PGF2α on the 10-pS Cl- channel because the stimulatory effect of PGF2α and H2O2 was not additive. Western blot analysis showed that infusion of PGF2α in vivo not only increased the expression of FP-R but also increased the expression of total NCC and phosphorylated NCC. We conclude that PGF2α stimulates the basolateral 10-pS Cl- channel in the DCT by activating FP-R through PKC/p38 MAPK and NADPH oxidase-dependent pathways. The stimulatory effects of PGF2α on the Cl- channel and NCC may contribute to PGF2α-induced increases in NaCl reabsorption in the DCT.

Hypoxia-Induced Cleavage Of Soluble ephrinA1 From Cancer Cells Is Mediated By MMP-2 And Associates With Angiogenesis In Oral Squamous Cell Carcinoma.

INTRODUCTION: ephrinA1 plays important roles in tumor angiogenesis. Matrix metalloproteases (MMPs) can cleave ephrinA1 from the cell membrane into extracellular environment. However, how soluble ephrinA1 is modulated by hypoxia and whether MMPs participate in this hypoxic process remains to be investigated in detail. METHODS: Thirty-seven patients with oral squamous cell carcinoma (OSCC) were included in the present study for HIF-1α, MMP-2, MMP-9 and ephrinA1 detection by immunohistochemistry. Serum samples from 35 patients were collected both preoperatively and postoperatively to confirm the existence of soluble ephrinA1 by ELISA. Block assay and Western blot analysis were further carried out to elucidate the proteolysis mechanism of ephrinA1 under hypoxic condition in vitro. RESULTS: Our data demonstrated that HIF-1α, MMP-2, MMP-9 and ephrinA1 expressed positively, and correlated with microvessel density in OSCCs, except for MMP-9. The serum expression level of ephrinA1 in OSCC patients decreased significantly after surgical removal of the solid tumors. In vitro experiments indicated that GM6001, a MMP-specific inhibitor, could reduce hypoxia-induced soluble ephrinA1 secretion from SCC cells. Further Western blot analysis confirmed that both HIF-1α and MMP-2 were up-regulated by hypoxia in a similar time-dependent manner, with the MMP-9 expression unchanged during this course. CONCLUSION: These results suggested a possible novel mechanism that ephrinA1 secretion is mediated by HIF-1α/MMP-2 signaling cascade which may play pivotal roles in OSCC neovascularization in a paracrine manner.

[The study of combined unilateral intraoral and extraoral reduction approach in the treatment of anterior temporo-mandibular joint dislocation].

OBJECTIVE: To observe the clinical outcomes of a combined unilateral intraoral and extraoral reduction approach in the treatment of anterior temporomandibular joint (TMJ) dislocation. METHODS: Postural muscular chains were utilized in the biomechanical analysis of stomatognathic systems for improving TMJ repositioning approaches. A total of 87 patients with anterior TMJ dislocation were included in the present study. A combined unilateral intraoral and extraoral reduction approach was applied, and the clinical effects were evaluated. RESULTS: Biomechanical analysis reveal that reflexive contrac-tion of the maxillary muscle group was blocked sufficiently during the combined unilateral intraoral and extraoral reduction process. All dislocated TMJs were set successfully and efficiently with few complications. CONCLUSIONS: Combined unilateral intraoral and extraoral reduction approach is an effective, convenient, and minimally invasive way to treat anterior TMJ dislo-cations.

Contamination status of bisphenol A and its analogues (bisphenol S, F and B) in foodstuffs and the implications for dietary exposure on adult residents in Zhejiang Province.

An effective method has been developed for the simultaneous determination of four bisphenols (bisphenol A, S, F and B) in various foodstuffs. The contaminants were extracted by QuEChERS-based strategy and subjected to ion-exchange solid-phase extraction for further clean-up. The critical variables were screened by Plackett-Burman design and then optimized by central composite design. Under the optimized conditions, satisfactory accuracy (recoveries 76%-116%) and precision (RSDs < 12%) were achieved. The established method was then used to assess the contamination status of 379 real samples. Bisphenol A was demonstrated to be the predominant bisphenol with highest incidence (79.7%) and average concentration (14.3 µg/kg). The positive rates (mean concentration) of bisphenol S, F and B were 37.7% (1.6 µg/kg), 26.9% (1.4 µg/kg) and 0.0% (not detected), respectively. Finally, the daily dietary intakes of ∑4bisphenolsfor adult residents were estimated (55.9-76.1 ng/kg bw/day) according to the contamination concentrations and the daily recommended intakes.

Norepinephrine-Induced Stimulation of Kir4.1/Kir5.1 Is Required for the Activation of NaCl Transporter in Distal Convoluted Tubule.

The stimulation of ß-adrenergic receptor increases thiazide-sensitive NaCl cotransporter (NCC), an effect contributing to salt-sensitive hypertension by sympathetic stimulation. We now test whether the stimulation of ß-adrenergic receptor-induced activation of NCC is achieved through activating basolateral Kir4.1 in the distal convoluted tubule (DCT). Application of norepinephrine increased the basolateral 40 pS K+ channel (Kir4.1/Kir5.1 heterotetramer) in the DCT. The stimulatory effect of norepinephrine on the K+ channel was mimicked by cAMP analogue but abolished by inhibiting PKA (protein kinase A). Also, the effect of norepinephrine on the K+ channel in the DCT was recapitulated by isoproterenol but not by α-adrenergic agonist and blocked by propranolol, suggesting that norepinephrine effect on the K+ channel was mediated by ß-adrenergic receptor. The whole-cell recording shows that norepinephrine and isoproterenol increased DCT K+ currents and shifted the K+ current ( IK) reversal potential to negative range (hyperpolarization). Continuous norepinephrine perfusion (7 days) increased DCT K+ currents, hyperpolarized IK reversal potential, and increased the expression of total NCC/phosphorylated NCC, but it had no significant effect on the expression of NKCC2 (type 2 Na-Cl-K cotransporter) and ENaC-α (epithelial Na channel-α subunit). Renal clearance study demonstrated that norepinephrine perfusion augmented thiazide-induced urinary Na+ excretion only in wild-type but not in kidney-specific Kir4.1 knockout mice, suggesting that Kir4.1 is required for mediating the effect of norepinephrine on NCC. However, norepinephrine perfusion did not affect urinary K+ excretion. We conclude that the stimulation of ß-adrenergic receptor activates the basolateral Kir4.1 in the DCT and that the activation of Kir4.1 is required for norepinephrine-induced stimulation of NCC.

Bradykinin Stimulates Renal Na+ and K+ Excretion by Inhibiting the K+ Channel (Kir4.1) in the Distal Convoluted Tubule.

Stimulation of BK2R (bradykinin [BK] B2 receptor) has been shown to increase renal Na+ excretion. The aim of the present study is to explore the role of BK2R in regulating Kir4.1 and NCC (NaCl cotransporter) in the distal convoluted tubule (DCT). Immunohistochemical studies demonstrated that BK2R was highly expressed in both apical and lateral membrane of Kir4.1-positive tubules, such as DCT. Patch-clamp experiments demonstrated that BK inhibited the basolateral 40-pS K+ channel (a Kir4.1/5.1 heterotetramer) in the DCT, and this effect was blocked by BK2R antagonist but not by BK1R (BK B1 receptor) antagonist. Whole-cell recordings also demonstrated that BK decreased the basolateral K+ conductance of the DCT and depolarized the membrane. Renal clearance experiments showed that BK increased urinary Na+ and K+ excretion. However, the BK-induced natriuretic effect was completely abolished in KS-Kir4.1 KO (kidney-specific conditional Kir4.1 knockout) mice, suggesting that Kir4.1 activity is required for BK-induced natriuresis. The continuous infusion of BK with osmotic pump for 3 days decreased the basolateral K+ conductance and the negativity of the DCT membrane. Western blot showed that infusion of BK decreased the expression of total NCC and phosphorylated NCC. Renal clearance experiments demonstrated that thiazide-induced natriuresis was blunted in the mice receiving BK infusion, suggesting that BK inhibited NCC function. Consequently, mice receiving BK infusion for 3 days were hypokalemic. We conclude that stimulation of BK2R inhibits NCC activity, increases urinary K+ excretion, and causes mice hypokalemia and that Kir4.1 is required for BK2R-mediated stimulation of urinary Na+ and K+ excretion.

Optimization for quick, easy, cheap, effective, rugged and safe extraction of mycotoxins and veterinary drugs by response surface methodology for application to egg and milk.

A multiclass method was proposed for the simultaneous determination of various classes of veterinary drugs (n = 65), mycotoxins and metabolites (n = 39) in egg and milk by ultra-high performance liquid chromatography-tandem mass spectrometry. The contaminants were extracted by QuEChERS-based strategy including salt-out partitioning and dispersive solid-phase extraction for cleanup further. With the aim of maximizing throughput and extraction efficiency, Plackett-Burman design was employed initially for screening significant variables. And response surface methodology based on central composite design was conducted to achieve optimal conditions in details: 3.35% (v/v) of formic acid in acetonitrile, 1.2 g of NaCl, 0.5 g of anhydrous NaAc, 300 mg of C18 and 140 mg of primary secondary amine. Satisfactory analytical characteristics in validation, in aspects of accuracy (70%-105% for mycotoxins and quinolones, 55%-80% for sulphonamides and 40%-105% for other veterinary drugs), precision (inter-day RSDs < 14%) and sensitivity (LOQs ranged from 0.01 µg/kg to 31 µg/kg), were achieved under the optimized conditions. The matrix effects were evaluated and compensated by the use of matrix-matched calibration curves (R2 > 0.987). In practice, 45 eggs and 30 milk samples were investigated by the established method, of which positive finding aflatoxin in milk and sterigmatocystin in eggs.

[Intermittent convulsions for 1.5 years and psychomotor retardation in a girl].

The study reports a girl with pyridoxine-dependent epilepsy. The girl was admitted at the age of 2 years because of intermittent convulsions for 1.5 years and psychomotor retardation. She had a history of "hypoxia" in the neonatal period. At the age of 5 months recurrent epileptic seizures occurred. The child was resistant to antiepileptic drugs, and had many more seizures when she got cold or fever. She also had a lot of convulsive status epilepticus. No discharges were found during several video-EEG monitorings. Cerebral MRI examinations showed normal results. So Dravet syndrome was clinically suspected. ALDH7N1 gene mutation analysis revealed two heterozygote mutations, and pyridoxine-dependent epilepsy was thus confirmed. Seizures were generally controlled after pyridoxine supplementation.

The treatment effect of porous titanium alloy rod on the early stage talar osteonecrosis of sheep.

Osteonecrosis of the talus (ONT) may severely affect the function of the ankle joint. Most orthopedists believe that ONT should be treated at an early stage, but a concise and effective surgical treatment is lacking. In this study, porous titanium alloy rods were prepared and implanted into the tali of sheep with early-stage ONT (IM group). The curative effect of the rods was compared to treatment by core decompression (DC group). No significant differences in bone reconstruction were observed between the two groups at 1 month after intervention. After 3 months, the macroscopic view of gross specimens of the IM group showed ordinary contours, but the specimens of the DC group showed obvious partial bone defects and cartilage degeneration. Quantitative analysis of the reconstructed trabeculae by micro-CT and histological study suggested that the curative effect of the IM group was superior to that of the DC group at 3 months after intervention. These favorable short-term results of the implantation of porous titanium alloy rods into the tali of sheep with early-stage ONT may provide insight into an innovative surgical treatment for ONT.

Development of a clinically relevant animal model for the talar osteonecrosis in sheep.

There are a lot of reports and reviews about osteonecrosis of the talus (ONT), yet reports about the animal model of ONT to evaluate proper therapeutic approaches are rarely heard. In our study, a novel animal model was established. Pure ethanol was injected into the cancellous bone of sheep's talus. Macroscopic observation, X-ray, CT and histology were performed at two, four, 12 and 24 weeks postoperatively. It was revealed that the trabeculae of talar head began to change their structure after two weeks postoperatively compared to the normal talus. The ONT was obvious at the end of the fourth week, and their outstanding feature was the damage of trabeculae bone and formation of cavities. CT scans and pathological changes of the subjects all showed characteristics of the early stage of osteonecrosis, also the sections of the specimens confirmed necrosis of tali. By 12 weeks, the phenomenon of necrosis still existed but fibrous tissue proliferated prominently and bone reconstruction appeared in certain area. Most specimens (3/4) got late stage necrosis which presented as synarthrosis in X-ray and mass proliferation of fibrous tissue in histology at the end of 24 weeks. The novel animal model of ONT was successful, and it is inclined to deteriorate without any intervention. The study provides us a new way to evaluate various treatments on ONT in laboratory, which may eventually pave way to clinical applications.

[Preliminary study of gene expression profile associated with risk classification of childhood patients with acute lymphoblastic leukemia].

OBJECTIVE: To explore genes associated with risk classification of childhood acute lymphoblastic leukemia (ALL) by gene chip technology. METHODS: Group A and B were both composed of three newly diagnosed ALL cases with standard risk. After re-evaluation, group B was relegated to high-risk. The control group was composed of three idiopathic thrombocytopenic purpura (ITP) patients. The gene expression profiles of group A and B were studied by Illumina Human-6 Beadchip. Eighty-two ALL patients were selected as the experimental group and 21 with normal bone marrow as control group for real-time quantitative RT-PCR (RQ-PCR). RESULTS: (1) There were 19 genes expressed differently between group B and A, including 14 up-regulated as ABCC4 and BCL11A, 5 down-regulated genes as TOP2A. (2) ABCC4 and BCL11A were validated by RQ-PCR and their expression level was higher in the high risk group than in the standard risk group (P < 0.05). The gene expression level in the group A and B was higher than that in the normal control group (P < 0.01). TOP2A was also validated by RQ-PCR and its expression level in the high risk group was lower than that in the standard risk group (P < 0.05). The gene expression level in the groups A and B was lower than that in the normal control group and the difference was statistically significance (P < 0.01). (3) There was a significant difference in the expression level of ABCC4 between the remission and unremission patients (P < 0.05). There was no significant difference in the expression level of BCL11A between different clinical indicators (P > 0.05). There was significant difference in the expression level of TOP2A between remission and prednisone good responder groups (P < 0.05). CONCLUSIONS: Fourteen genes studied were involved in the pathogenesis and drug resistance mechanism in childhood ALL patients. Investigation of gene expression profile will be helpful for predicting drug resistance, prognosis, early intervention and target therapy in childhood ALL.

[Recombinant human bone morphogenetic protein-2 transform NIH3T3 fibroblast to osteo-like cells].

OBJECTIVE: To examine the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) on NIH3T3 cells. METHODS: The NIH3T3 cells were cultured in DMEM with 50 microg/L rhBMP-2. The proliferation ability, alkaline phosphatase (ALP) activity and osteocalcin (OC) quantity of NIH3T3 cells were investigated. RESULTS: The cells showed decreased proliferation ability but enhanced ALP activity and OC quantity. CONCLUSION: 50 microg/L rhBMP-2 can transform NIH3T3 fibroblasts to osteo-like cells.

Two new bicoumarins from Trifolium repens L.

Two new bicoumarins, named repensin A (1) and B (2), have been isolated from Trifolium repens. On the basis of spectral data, the structures of 1 and 2 have been established as 7-methoxy-7',8'-dihydroxy-8,6'-bicoumarinyl and 7,5'-dihydroxy-3,6'-bicoumarinyl, respectively.