A high-power long lifetime beam dump for the Thomson scattering diagnostic system in the XuanLong-50 experiment

The Energy iNNovation's XuanLong-50 is a spherical torus experiment with up to 10 s plasma operation duration. A 3 J/50 Hz pulsed laser is used in the Thomson scattering diagnostic system that is developed to measure the time evolutions of plasma electron temperature and density profiles. The expected laser pulse number is about 7.5 × 10⁶/year with a power load of 150 W. To meet at least 1-year lifetime requirement, a Chevron type beam dump with polished molybdenum plates is designed and fabricated, which absorbs the laser beam energy in a 3D structure to reduce the laser fluence deposited on the material surface. To prevent the backscattered stray light from interfering with the Thomson scattering measurements, a 7.5 m beam path with folding mirrors is set between the beam dump and the plasma scattering volumes. Details of the beam dump design procedure including the laser beam profile control, multi-pulse laser damage threshold, heat dissipation, Zemax modeling, folding mirror selection, and beam path enclosure are presented together with the testing results.

A novel polychromator calibration method for Thomson scattering diagnostics

Polychromators are most frequently used in Thomson scattering (TS) diagnostics to analyze the scattered light spectrum and intensity so that the plasma electron temperature (T_e) and density (n_e) can be derived. For T_e measurements, the spectral response of the polychromator channels and the relative spectral responsivities need to be calibrated. The spectral response is calibrated with a bromine tungsten lamp and a monochromator in a conventional way. A novel method for calibrating the relative spectral responsivities of the polychromators is described in detail. A broadband pulsed Light Emission Diode (LED) is used, which has a spectral irradiance similar to that of the TS spectrum, and the LED can be driven in pulse mode with the pulse width similar to the TS signal pulse width of about 10-20 ns full width at half maximum. This new method allows for the calibration to be done after the polychromator is fully installed, and in situ system calibration can be easily performed, showing the advantages of accuracy, simplicity, efficiency, and flexibility. For n_e measurements, absolute sensitivity calibration is done by Rayleigh scattering with argon gas. Formulas for calculating the plasma density from the calibration data and the polychromator signals from the off-laser wavelength channels are presented.

Thomson scattering diagnostic system for the XuanLong-50 experiment

A 15-point Thomson scattering diagnostic system is developed for ENN's spherical torus experiment XuanLong-50 (EXL-50). A BeamTech laser with 3 J/pulse (1064 nm wavelength) at 50 Hz repetition rate is chosen for measurements during EXL-50 plasma operations. To enable measurements at low density (∼0.5 × 10¹⁸ m^-3) plasma operations, the opto-mechanical subsystems are carefully designed to maximize the collection and transmission of the scattered light and to minimize the stray light level. In addition, the high bandwidth trans-impedance amplifiers and segmented high speed waveform digitizers allow for the application of muti-pulse averaging to further improve the signal-to-noise ratio. Details of the diagnostic system are described and initial experimental results are presented.

[Effect of porous zirconia ceramics on proliferation and differentiation of osteoblasts]

OBJECTIVE

To investigate the effect of porous surface morphology of zirconia on the proliferation and differentiation of osteoblasts.

METHODS

According to different manufacturing and pore-forming methods, the zirconia specimens were divided into 4 groups, including milled sintering group (M-Ctrl), milled porous group (M-Porous), 3D printed sintering group (3D-Ctrl) and 3D printed porous group (3D-Porous). The surface micromorphology, surface roughness, contact angle and surface elements of specimens in each group were detected by scanning electron microscope (SEM), 3D laser microscope, contact angle measuring device and energy-dispersion X-ray analysis, respectively. MC3T3-E1 cells were cultured on 4 groups of zirconia discs. The cell morphology of MC3T3-E1 cells on zirconia discs was eva-luated on 1 and 7 days by SEM. The cell proliferation was detected on 1, 3 and 5 days by cell counting kit-8 (CCK-8). After osteogenic induction for 14 days, the relative mRNA expression of alkaline phosphatase (ALP), type Ⅰ collagen (Colla1), Runt-related transcription factor-2 (Runx2) and osteocalcin (OCN) in MC3T3-E1 cells were detected by real-time quantitative polymerase chain reaction.

RESULTS

The pore size [(419.72±6.99) μm] and pore depth [(560.38±8.55) μm] of 3D-Porous group were significantly larger than the pore size [(300.55±155.65) μm] and pore depth [(69.97±31.38) μm] of M-Porous group (P < 0.05). The surface of 3D-Porous group appeared with more regular round pores than that of M-Porous group. The contact angles of all the groups were less than 90°. The contact angles of 3D-Ctrl (73.83°±5.34°) and M-Porous group (72.7°±2.72°) were the largest, with no significant difference between them (P>0.05). Cells adhered inside the pores in M-Porous and 3D-Porous groups, and the proliferation activities of them were significantly higher than those of M-Ctrl and 3D-Ctrl groups after 3 and 5 days' culture (P < 0.05). After 14 days' incubation, ALP, Colla1, Runx2 and OCN mRNA expression in 3D-Porous groups were significantly lower than those of M-Ctrl and 3D-Ctrl groups (P < 0.05). Colla1, Runx2 and OCN mRNA expressions in M-Porous group were higher than those of 3D-Porous group (P < 0.05).

CONCLUSION

The porous surface morphology of zirconia can promote the proliferation and adhesion but inhibit the differentiation of MC3T3-E1 cells.

[Occlusion variation of posterior implant-supported single crown: a prospective 4-year follow-up study]

Objective: To analyze the longitudinal variation of occlusal force distribution and occlusal contact time in posterior implant-supported single crown with the computerized occlusal analysis system. Methods: Partially edentulous patients who visited the Department of Prosthodontics, Peking University School and Hospital of Stomatology between December 2012 and December 2013, and had received implant-supported single crown in the posterior region were enrolled. The participants underwent occlusal examinations with the computerized occlusal analysis system at 2 weeks, 3 and 6 months, 1, 2, 3, and 4 years after implant prosthesis delivery. The relative occlusal force (ROF) of implant prostheses, mesial adjacent teeth, and control teeth (corresponding teeth on the contralateral side) were recorded, and implant prosthesis occlusion time ratios (implant prosthesis occlusion time/occlusion time) were calculated. The interproximal contact between implant prostheses and adjacent teeth was evaluated using metal contact gauge and dental floss. Mechanical complications of implant prostheses were recorded. The paired t test or Wilcoxon signed-rank test was used to compare the implant prosthesis occlusion time ratios and ROF of implant prostheses at 2 different times as a self-control. The differences in ROF between implant prostheses and control teeth in the same participant at the same time were also analyzed using paired t test. Using a complementary log-log model, the correlation between the occurrence of veneering material fracture and ROF of implant prosthesis was analyzed with gender, age and follow-up time as the control variables. Results: Thirty-seven posterior fixed implant-supported single crowns in 33 participants, including 16 men and 17 women aged (42.8±12.9) years (23.9 to 70.0 years) were followed up for 2 weeks to 4 years [(38.3±15.2) months]. The ROF of implant prostheses increased significantly (P<0.01) from 2 weeks [(7.0±4.2)%] to 3 months [(9.9±6.8)%], whereas those of control natural teeth decreased significantly (P<0.05) from (13.1±6.1)% to (11.4±5.5)%. The ROF of implant prostheses continued to increase from 6 months to 1 year, from 1 year to 2 years and from 2 years to 3 years, with significant differences (P<0.05). Implant prosthesis occlusion time ratios also increased significantly between 2 weeks and 3 months and between 3 months and 6 months (P<0.05). No significant differences were found between other time points (P>0.05). For comparison between implant prosthesis and control teeth at the same time point, the ROF of the implant prostheses [(7.5±4.2)%] were significantly lower than those of the control teeth [(13.8±6.0)%] at 2 weeks (P<0.01). While at 4 years, ROF of implant prostheses [16.7% (8.6%, 32.4%)] became significantly higher than those of control teeth [9.5% (4.9%, 18.0%)] (P<0.05). ROF of the implant prostheses did not differ significantly with those of the control teeth in other follow-up time points (P>0.05). The 4-year cumulative incidence of proximal contact loss rate was 32% (22/68). The incidences of veneering material fracture and prostheses loosening were 16% (6/37) and 8% (3/37), respectively. Logistic regression showed a significant correlation between veneering material fracture and ROF of implant prostheses (r=0.26, P<0.05). Conclusions: The occlusal force and occlusal contact time of posterior implant-supported single crown change over time in 4-year follow-up period, which is mainly reflected in the increasing occlusal force and occlusal contact time. The occlusion of posterior implant prostheses should be carefully monitored during follow-up examinations, and occlusal adjustment should be considered when necessary.

[Advance in research of occlusal dysesthesia]

Occlusal dysesthesia (OD) or phantom bite syndrome refers to a persistent complaint of uncomfortable bite sensation with no obvious occlusal discrepancy. OD is a rare condition, and is usually associated with emotional distress and triggered by dental treatments. The diagnosis and management of OD patients still remains a major challenge for dental practitioners and affected patients. This topical review aims to describe the properties, etiologies, diagnosis, managements and prognosis of OD comprehensively.

[Adenosine triphosphate induced odontoblastic differentiation of human dental pulp cells in vitro and in vivo]

Objective: To choose a suitable efficient concentration of adenosine triphosphate (ATP) which can induce human dental pulp cells (HDPC) differentiate into odontoblast successfully, and explore the role of this concentration of ATP in dentin regeneration in vivo. Methods: HDPC were treated with different concentrations (0, 10, 400, 600, 800 μmol/L) of ATP. Then cell counting kit-8 (CCK-8), quantitative real-time PCR, and Western blotting were used to detect the cell proliferation and the expressions of odontoblastic differentiation related markers, dentin matrix protein 1 (DMP1) and dentin sialophosphoprotein (DSPP). Alizarin red S staining experiment was used to analyze the effect of ATP on the mineralization ability of HDPC. By the above experiments, the suitable effective concentration of ATP was chosen to pretreat the HDPC for 7 days, then cells were seeded on gelfoam, inserted into the root canal fragment, and subsequently transplanted into the subcutaneous space on the back of immunodeficient mice, after three months, the samples were stained with HE for histological analysis. Results: The CCK-8 results in 5 d showed that 10 μmol/L ATP obviously promoted the proliferation of HDPC, while the 600 and 800 μmol/L ATP apparently inhibited the HDPC proliferation, however, the proliferation in 800 μmol/L ATP group was lower than that of 600 μmol/L ATP group (P<0.05). qPCR and Western blotting results showed that the 600 and 800 μmol/L ATP significantly up-regulated the DMP1 and DSPP expressions (P<0.05), furthermore, there was no significant difference in the two groups, but no changes were found in other groups (P>0.05). After 21 days of culturing, there were obvious mineralization nodules in 600 and 800 μmol/L ATP groups, but no mineralization nodules in other groups. Quantitative analysis of the staining results showed the A value in 0, 10, 400, 600, and 800 μmol/L ATP groups were respectively 1.05±0.15, 1.11±0.23, 1.15±0.17, 3.65±0.30, and 3.40±0.43, and the A value in 600 and 800 μmol/L ATP groups were higher than those of other groups; however, there was no difference in 600 and 800 μmol/L ATP groups. The histological analysis showed that 600 μmol/L ATP could induce the HDPC differentiate into dentin-like structure in the root canal fragment. Conclusions: Therefore, the suitable effective concentration of ATP is 600 μmol/L, which could induce HDPC differentiate into odontoblast-like cells, and form the dentin-like structure in vivo.

[Research progress on factors influencing early liver dysfunction after liver transplantation]

Liver transplantation is the most effective treatment for end-stage liver disease, and early graft dysfunction often occurs after surgery. Early liver dysfunction after liver transplantation has become one of the complications after liver transplantation, which seriously affects the graft and patient survival. Therefore, reducing its occurrence can be an important means to improve the prognosis of recipients after liver transplantation. This paper discusses the research progress on the definition, influencing factors, and prognosis and prediction model in order to provide better prevention and effective reference for improving the success rate and prognosis of early liver dysfunction in recipients after liver transplantation.

[Present situation and future of occlusal splint in treatment of oral diseases]

Occlusal splint is a removable device for the treatment of oral and maxillary diseases with reversible occlusal treatment property. When patients wear the occlusal splint, the occlusal contact state can be changed and the position of the lower jaw may be adjusted, with the improvement of functions of temporomandibular joints and masticatory muscles. There are various types of occlusal splints, among which stabilization splint, soft occlusal splint and repositioning splint are widely used in the treatment of temporomandibular disorders and night bruxism. For the patients requiring occlusal reconstruction, occlusal splint can be used as an important means to adjust and verify the therapeutic jaw position. As a major trend of research in future, the digital design and production of occlusal splint are still in the initial stage and need to be further improved.

[Effect of long-term resistance exercise on masseter muscle mechanical hyperalgesia in rats]

OBJECTIVE

To investigate the effect of long-term resistance exercise of hindlimb on mechanical hyperalgesia of bilateral masseter muscle in rats with or without occlusal interference.

METHODS

Six-teen male Sprague-Dawley rats (220-250 g) were randomly divided into four groups: the naive control group, naive exercise group, occlusal interference control group, and occlusal interference exercise group. The rats in occlusal interference groups (occlusal interference control group and occlusal interference exercise group) obtained occlusal interference with 0.4 mm-thick crowns bonded to the right maxillary first molars. The rats in exercise groups (naive exercise group and occlusal interference exercise group) performed squat-type resistance exercises for 30 minutes, once a day, 5 days/week, lasting for 14 weeks. Resistance exercise was recorded every day. Mechanical withdrawal thresholds of bilateral masseter muscle were tested per week by use of modified electronic von-frey anesthesiometer. The rats were weighed per week. After the 14-week exercise, the muscle strength of the hindlimb was tested with a grip strength meter. Muscle (gastrocnemius and soleus) weight of bilateral hindlimb and length of bilateral fibula of the rats were obtained. The muscle-mass/body-mass ratios and muscle-mass/fibula-length ratios were calculated.

RESULTS

Between the naive control group and naive exercise group, there was no significant difference in the mechanical withdrawal thresholds of bilateral masseter muscle for the 0-4 weeks (P>0.05). During the 5-14 weeks, the mechanical withdrawal thresholds of the rats in the naive exercise group were higher than those in the naive control group (P<0.05). Between the occlusal interference control group and occlusal interference exercise group, there was no significant difference in the mechanical withdrawal thresholds of bilateral masseter muscle for the 0-6 weeks (P>0.05). During the 7-14 weeks, the mechanical withdrawal thresholds of rats in the naive exercise group were higher than those in the occlusal interference control group (P<0.05). After the 14week exercise, the body mass of the rats in nonexercise group (the naive control group and occlusal interference control group) were larger than those in exercise group [(462±6) g vs. (418±14) g, P<0.05]. And the muscle strength of hindlimb of the rats in exercise group were bigger than those in non-exercise group [(6.75±0.13) N vs. (5.41±0.15) N, P<0.01].

CONCLUSION

long-term resistance exercise can increase mechanical withdrawal thresholds of the bilateral masseter muscle in rats with or without masseter muscle mechanical hyperalgesia.

[The loss of interproximal contact between posterior fixed implant prostheses and adjacent teeth: a retrospective study]

OBJECTIVE

To investigate the interproximal contact(IC) loss rate and the associated risk factors of IC loss between posterior fixed implant prostheses and the adjacent teeth.

METHODS

Ninety-seven posterior fixed implant prostheses including 165 IC in 78 patients(34 men, 44 women) between 23 and 76 years of age were investigated. The period after restoration ranged from 1 to 44 months. The IC between implant prostheses and adjacent teeth was evaluated using a 30-μm-thick contact gauge and dental floss, and the IC was regarded as lost when the gauge or dental floss was inserted into an IC without any resistance at follow-up visits. The state of IC, region of implant prostheses, the condition of opposing dentition, the vitality of the adjacent teeth and the time interval of tooth loss were also confirmed for correlation analysis.

RESULTS

All 78 patients finished follow-up examination. Forty-eight of 165 IC(29%) were regarded as lost. The IC loss rate at the mesial aspect[75%(36/48)] was significantly greater than that at the distal aspect[25%(12/48)](χ(2)=7.344,P=0.007). The difference between IC loss rate in the maxilla[46% (22/48)] and that in the mandible[54%(26/48)] was not significant(χ(2)=2.992,P=0.084). Free-end[hazard ratio (HR)=2.870], and the time interval of tooth loss(HR=0.919) affected the loss of IC significantly(P<0.05, Cox regression analysis).

CONCLUSIONS

Loss of IC between posterior fixed implant prostheses and adjacent teeth was one of biological complications, which was observed frequently at follow-up visits. Patients who have the free-end fixed implant prostheses, or undergo short time interval of tooth loss before restoration may have high risk of the IC loss.

[Docosahexaenoic acid inhibits hypoxia-induced pulmonary arterial smooth muscle cells phenotype switching by inhibiting NFATc1 signaling]

Objective: To explore the molecular mechanism of docosahexaenoic acid (DHA) on regulating the phenotype switching of hypoxia-induced pulmonary arterial smooth muscle cells (PASMCs). Methods: The PASMCs were isolated from Sprague Dawley rats. PASMCs were divided into five groups: normal control group, hypoxia group (1%O(2, )94%N(2, )5% CO(2) stimulation for 12 hours), hypoxia+ DHA group (10 μmol/L DHA pretreatment followed by 12 hours hypoxia), hypoxia+ DHA+ NFATc1 overexpression group (transfection of the NFATc1 lentivirus for 24 hours, followed by hypoxia stimulation for 12 hours after 10 μmol/L DHA treatment), and hypoxia+ DHA+ siNFATc1 group (transfection the siNFATc1 for 24 hours, followed by hypoxia stimulation for 12 hours after 10 μmol/L DHA treatment). The hypoxia stimulation was achieved by use of a special hypoxia incubator (1%O(2, )94%N(2, )5%CO(2)). The expressions of NFATc1 of various groups were determined by qRT-PCR and Western blot. The expression of α-SMA was determined by immunofluorescence staining, qRT-PCR and Western blot. The expression of SM22 was determined by qRT-PCR. The proliferation of PASMC was determined by EDU staining. Results: The mRNA and protein expression levels of NFATc1 were significantly upregulated in hypoxia group compared with the normal control group (P<0.05), while hypoxia-induced upregulation of NFTAc1 could be significantly downregulated by DHA treatment (P<0.05). The α-SMA positive cell number, protein and mRNA levels of α-SMA and the mRNA level of SM22 were significantly lower in the hypoxia group than in normal control group, which could be significantly reversed by DHA, the protective effects could then be abolished by NFATc1 overexpression. Above indices were significantly lower in the hypoxia+ DHA+ siNFATc1 group than in hypoxia+ DHA+ NFATc1 overexpression group (P<0.05). The proliferation of PASMCs was significantly higher in the hypoxia group than in the control group (P<0.05), and which could be significantly reduced by DHA (P<0.05), and the protective effect of DHA could be significantly abolished by overexpression of NFATc1 (P<0.05). The proliferation of PASMCs was significantly lower in the hypoxia+ DHA+ siNFATc1 group than in the hypoxia+ DHA+ overexpression NFATc1 group (P<0.05). Conclusion: DHA could prevent hypoxia-induced PASMCs phenotype switching and proliferation by inhibiting NFATc1 signaling.

[Changes of productions of energy metabolism in masseter of rats induced by occlusal interference]

OBJECTIVE

To investigate the effect of occlusal interference on the energy metabolism of masticatory muscle by studying the changes of adenosine triphosphate (ATP), adenosine diphosphate (ADP), inosine monophosphate (IMP), phosphocreatine, creatine, lactate and pH level in masseter muscles of rats after occlusal interference.

METHODS

Fifty male Sprague-Dawley rats were randomly assigned into experimental group (n=40) and control group (n=10). In experimental group, 0.4 mm thick metal crown was cemented to the upper right first molar of the rat, and maintained for 3, 7, 10, 14 d separately (n=10 for each time point). No occlusal interference was applied for control group. Bilateral masseter muscles of all the rats were acquired under general anesthesia. The samples of 5 rats in each group were fully homogenized with 0.4 mol/L perchlorate (10 mL/g). The homogenates were centrifuged, filtered and analyzed for ATP, ADP, IMP, phosphocreatine, creatine and lactate content by high performance liquid chromatography. The other samples in each group were mixed with homogenates containing 5 mmol/L sodium iodoacetate (10 mL/g), then homogenized and measured for pH value by pH meter in thermostatic water bathunder 37 degrees centigrade.

RESULTS

Compared with control group, ATP content in bilateral masseter of the rats increased 3 d after occlusal interference [right side:(5.36±0.13) μmol/g,left side:(5.77±0.25) μmol/g] (P<0.05), and back to normal on 7, 10 and 14 d. There was an increase in IMP [right side:(0.21±0.03) μmol/g,left side:(0.19±0.03) μmol/g]and creatine content [right side:(24.76±2.94) μmol/g,left side:(27.75±2.23) μmol/g]in bilateral masseter of the rats 7 d after occlusal interference (P<0.05) and no difference was detected on 3, 10, and 14. Phosphocreatine content in bilateral masseter started to decline 7 d after occlusal interference and maintained the low level on 10 and 14 d [right side:(10.70±0.71) μmol/g, (11.57±0.52) μmol/g, (10.74±1.39) μmol/g, left side:(10.05±0.57) μmol/g, (10.75±1.12)μmol/g, (10.61±1.15) μmol/g](P<0.05). No change of ADP, lactate or pH level in bilateral muscles of the rats after occlusal interference was observed (P>0.05).

CONCLUSION

Occlusal interference influences the content of energy metabolites in masticatory muscle of rats, which may be related to the pathological process of masticatory muscles induced by occlusal interference, such as muscle pain, dysfunction and altered fiber architecture.

Molecular Changes Involving MEK3-p38 MAPK Activation in Chronic Masticatory Myalgia

The exact mechanism underlying chronic masticatory myalgia (CMM), a conspicuous symptom in temporomandibular disorders, remains unclear. This investigation compared gene expression profiles between CMM patients and healthy subjects. Peripheral blood leukocytes were collected in 8 cases and 8 controls and subjected to whole genome microarray analyses. Data were analyzed with Gene Ontology and interactive pathways analyses. According to Gene Ontology analysis, categories such as ion transport, response to stimuli, and metabolic process were upregulated. The pathway analysis suggested overexpression of the mitogen-activated protein kinase (MAPK) pathway in CMM patients and to a higher degree in a pathway network. Overexpression of representative members of the MAPK pathway-including MAPK kinase 3 (MEK3), calcium voltage-gated channel auxiliary subunit gamma 2 (CACNG2), and growth arrest and DNA damage-inducible gamma (GADD45G)-was validated with real-time polymerase chain reaction. The upregulation of MEK3 was negatively correlated with the age of the CMM group. In the next step, the authors focused on MEK3, the gene that exhibited the greatest degree of differential expression, and its downstream target protein p38 MAPK. The results revealed upregulation of MEK3, as well as phosphorylated MEK3 and phosphorylated p38 MAPK, in CMM patients. These results provide a "fingerprint" for mechanistic studies of CMM in the future and highlight the importance of MEK3-p38 MAPK activation in CMM.

Role of TRPV1 and ASIC3 channels in experimental occlusal interference-induced hyperalgesia in rat masseter muscle

BACKGROUND

Masticatory muscle pain may occur following immediate occlusal alteration by dental treatment. The underlying mechanisms are poorly understood. Transient receptor potential vanilloid-1 (TRPV1) and acid-sensing ion channel-3 (ASIC3) mediate muscle hyperalgesia under various pathologic conditions. We have developed a rat model of experimental occlusal interference (EOI) that consistently induces mechanical hyperalgesia in jaw muscles. Whether TRPV1 and ASIC3 mediate this EOI-induced hyperalgesia is unknown.

METHODS

Rat model of EOI-induced masseter hyperalgesia was established. Real-time polymerase chain reaction, Western blot and retrograde labelling combined with immunofluorescence were performed to evaluate the modulation of TRPV1 and ASIC3 expression in trigeminal ganglia (TGs) and masseter afferents of rats after EOI. The effects of intramuscular administration of TRPV1 and ASIC3 antagonists on the EOI-induced hyperalgesia in masseter muscle were examined.

RESULTS

After EOI, gene expressions and protein levels of TRPV1 and ASIC3 in bilateral TGs were up-regulated. The percentage of ASIC3- (but not TRPV1-) positive neurons in masseter afferents increased after EOI. More small-sized and small to medium-sized masseter afferents expressed TRPV1 and ASIC3 separately following EOI. These changes peaked at day 7 and then returned to original status within 10 days after EOI. Intramuscular administration of the TRPV1 antagonist AMG-9810 partially reversed this mechanical hyperalgesia in masseter muscle. No improvement was exhibited after administration of the ASIC3 antagonist APETx2. Co-injection of AMG-9810 and APETx2 enhanced the effect of AMG-9810 administration alone.

CONCLUSIONS

Peripheral TRPV1 and ASIC3 contribute to the development of the EOI-induced mechanical hyperalgesia in masseter muscle.

Influences of MxA gene -88 G/T and IFN-gamma +874 A/T on the natural history of hepatitis B virus infection in an endemic area

The influence of human genetics on the natural history of hepatitis B virus (HBV) infection may be diminished in endemic areas because infection at a young age predisposes to chronic HBV infection. The present study aimed to address this issue through the determination of the influences of single nucleotide polymorphisms (SNPs) of myxovirus resistence-1 (MxA) -88 G/T and interferon (IFN)-gamma +874 A/T on the natural history of HBV infection in endemic regions. One hundred adult patients with self-limiting HBV infection (positive for both anti-HBs and anti-HBc) and 340 adult patients with persistent HBV infection were recruited from southern China, an endemic area with an HBsAg carrier rate of 17.8%. SNPs of MxA -88 G/T and interferon (IFN)-gamma +874 A/T were typed using a protocol based on competitively differentiated polymerase chain reaction. A highly significant difference in the distribution of MxA -88 G/T was observed between those with persistent and self-limiting HBV infections. The latter displayed a lower frequency of the GG genotype (41.0% vs. 52.9%, P = 0.036) and a higher frequency of the TT genotype (16.0% vs. 2.4%, P = 0.000), compared to patients with persistent infection. These differences were not gender- or age-specific. However, a significant distribution difference of IFN-gamma +874 A/T was not observed. Between two groups of patients, respectively, the distribution frequencies of the AA genotype (65.0% vs. 72.8%, P = 0.139) and the TT genotype (2.0% vs. 1.2%, P = 0.894) were found. These results suggest that MxA gene -88 G/T and IFN-gamma +874 A/T behave differently in endemic HBV infections. Further study is necessary to clarify the influences of human genetics on endemic HBV infections.

Increased Body Weight Via Injecting Myogenic Expression Growth Hormone-Releasing Hormone (GHRH) Plasmid DNA into Sheep

The ectopic expression of a sheep growth hormone-releasing hormone (GHRH) from muscle tissues, using a myogenic plasmid expression vector pM-GHRH, has been shown to result in enhanced animal growth. Animal injected with pM-GHRH alone exhibited a daily weight gain rate of 0.84+/-0.02%/d (p < 0.05), while that of the control animal was only 0.73+/-0.04%/d. A more significant growth enhancement was observed in the group treated with pM-GHRH plus 0.25% bupivacaine. The animal displayed a daily weight gain rate of 0.87+/-0.03%/d (p<0.01). In addition, the group treated by pM-GHRH and bupivacaine had higher levels of growth hormone (GH) in their blood (1.18+/-0.33 ng/mL) compared with the group treated by pM-GHRH vector alone (p < 0.05). Evaluation of body composition by dissection and histochemical analysis indicated a significant increase in bulk with no organomegaly or associated pathology. PCR analysis demonstrated that there was little plasmid residue detected in the pM-GHRH treated sheep.

Ghrelin and truncated ghrelin variant plasmid vectors administration into skeletal muscle augments long-term growth in rats

Ghrelin is an acylated peptide recently identified as an endogenous ligand for the growth hormone (GH) secretagogues (GHSs) receptor (GHS-R) and is involved in a novel system for regulating GH release. To study the biological activities of ghrelin using plasmid vector administration, we constructed myogenic expression vectors containing the full length cDNA of swine ghrelin-28 (pGEM-wt-sGhln) and truncated variant (pGEM-tmt-sGhln) consisting of the first seven residues of ghrelin (including Ser3 substituted with Trp3) with addition of a basic amino acid, Lys (K) at the C-terminus. After intramuscular injection of pGEM-wt-sGhln and pGEM-tmt-sGhln, RT-PCR analysis demonstrated that the ectopic expressions of ghrelin and its variant were observed 30 days post-injection. The level of GH increased in rat serum, and was significantly higher than that of the control group 20 days post-injection with pGEM-tmt-sGhln (P < 0.05). Administration of 150 microg of pGEM-wt-sGhln and pGEM-tmt-sGhln enhanced growth in rats over 30 days and great stimulatory responses were observed at day 10 and 20 post-injection respectively, whose body weight gains were on average 15% (P < 0.05) and 21% P < 0.033 significantly heavier than controls. These results suggested that skeletal muscle might have the potential to perform post-translational acylation for ghrelin, and short ghrelin variant might have the biological effects as wild type ghrelin.