Objective To identify the effect of health risk behaviors on accidental injury of adoles-cents.Then analyze the strength and approach of the health risk behaviors. Methods Cluster sampling on various stages and strata methods was adopted. The adolescents from grade one to three in junior school students and grade one to three in senior high school students completed the questionaire. A total of 4408 students were surveyed and 4309 samples were valid. Path analysis was used to understand how factors could influence injury incidence. Results The incidence of adolescent injury was 15.53%. Statistical differences were found between genders (male 17.77%,female 13.36%,χ2=15.91, P<0.01),education levels (junior high school 17.36%,senior high school 13.99%,χ2=11.45, P<0.01) and cities ( Beijing 12.97%,Zhongs-han 17.95%,χ2=20.33, P<0.01) . Those who got injured were found with more health risk behaviors. Health risk behavior was the direct influencing factor to injury,as well as a possible risk factor to multiple injuries. Conclusion Health risk behaviors can strongly affect adolescent injury,and can be an indicator. Reducing health risk behaviors is important in adolescent injury prevention.

BACKGROUND:Our previous studies have shown that a soft substrate has a significant effect on morphology and cytoskeleton of rat bone marrow mesenchymal stem cel.
OBJECTIVE:To explore the effect of polyacrylamide gels as soft substrates with different elastic moduli on the chondrogenic differentiation of human synovial-derived mesenchymal stem cels.
METHODS:The synovium was harvested from patients with osteoarthritis under sterile conditions, and primary human synovial-derived mesenchymal stem cels were separated using limiting dilution assay. The flow cytometry and multi-directional differentiation experiments were used to identify the cel surface markers and function of the human synovial-derived mesenchymal stem cels, respectively. The polyacrylamide gels with the elastic modulus of 0.4, 6, 30 kPa, which were made using various amounts of acrylamide and bis-acrylamide, were used to culture human synovial-derived mesenchymal stem cels under induction with transforming growth factor-β1 for 7 and 14 days. RT-PCR was used to test the expression of chondrogenic genes, type II colagen gene and cartilage acidic protein 1. The 6-wel cel culture plates served as controls.
RESULTS AND CONCLUSION: The human synovial-derived mesenchymal stem cels showed different cel morphology in the different elastic modulus of polyacrylamide gels. The expression of type II colagen gene and cartilage acidic protein 1 were affected by the different elastic modulus of polyacrylamide gels and culture time, and there was an interaction between these two factors. At 7 days of induction, the expression of cartilage acidic protein 1 gene on 6 kPa polyacrylamide gels was the highest (F=44.350,P=0.000); meanwhile, the expression of type II colagen gene on 0.4 kPa polyacrylamide gels was the highest (F=6.384,P=0.005). These findings indicate that polyacrylamide gels with lower elastic modulus are superior to routine culture plates to promote the chondrogenic differentiation of human synovial-derived mesenchymal stem cels.

Veratridine, a blocker of inactive gate of sodium channel, was used to perfuse L5 dorsal root ganglion (DRG) topically. Afferent activities of type A single fiber from these DRGs were recorded. It was found that after a 10-min bath of veratridine (1.8-3 micromol/L), some of the primary silent DRG neurons were triggered by touch or pressure on the receptive fields or by electrical stimulation of the sciatic nerve to produce high-frequency firing, which was termed triggered oscillation presenting a U-type of interspike intervals (ISI) or other types of oscillations. The longer the intervals between stimulating pulses, the more stimulating pulses were needed to trigger the oscillation. The oscillation, triggered by electric stimuli with different duration or patterns, had no significant difference in their patterns. The duration of the inhibitory period after a triggered oscillation was generally 30-90 s. It was also observed that this kind of triggered oscillation was induced by afferent pulses of the same neurons. These results suggest that triggered oscillation, which may contribute to the fit of triggered pain, can be produced in primary sensory neurons after application of veratridine.
Action Potentials ; physiology ; Animals ; Female ; Ganglia, Spinal ; cytology ; drug effects ; Male ; Neurons, Afferent ; physiology ; Rats ; Rats, Sprague-Dawley ; Sodium Channel Blockers ; pharmacology ; Veratridine ; pharmacology

OBJECTIVETo evaluate the antibacterial efficacy of KaVo KEY laser on Enterococcus faecalis (E. faecalis) within infected root canals and roots surface in vitro.

METHODSFifty single-rooted teeth were selected, and infected root canals and roots surface vitro models were prepared. Then, these specimens were divided into three groups. First group were untreated as blank control. The other two groups were the laser groups: Irradiated 15 s and 30 s respectively with 80 mJ and 140 mJ in root canals and on roots surface. Microbiological samples were collected from root canals and roots surface at two time points (before irrigation and immediately after irrigation). The dentin chips from three different zone of part of root canals in each group were immediately collected and were cultured for 24 h in brain heart infusion (BHI).

RESULTSThe number of E. faecalis in root canal and root surface in each of the groups were effectively reduced (P < 0.05), and there was no significant difference between each two groups (P > 0.05). Compared with the blank control, the bacterial number in 100 microm of dental tubules decreased after specimens treated with 80 mJ, and the experimental group irradiated 15 s was a significant decease (P < 0.05). The other groups were no changed in different zone of dental tubules.

CONCLUSIONKaVo KEY laser is effective on sterilizing infected root canals and roots surface. It has also significant effect on bacterial in superficial dental tubules with low energy and short time.

Dental Pulp Cavity ; microbiology ; Enterococcus faecalis ; radiation effects ; Humans ; Lasers

OBJECTIVEPosterolateral intertransverse process fusion was performed in aged and young adult female rabbits lumbar spine using recombinant human bone morphogenetic protein-2 (rhBMP-2) and autograft to reveal the function of rhBMP-2 on spinal fusion on aged animals.

METHODSA total of 24 female New Zealand white rabbits included 12 young adult of 6 months and 12 aged of 2-year-old, was divided into 4 groups: (1) young adult autologous iliac crest bone group [ICBG(Y), n=6); (2) young adult rhBMP-2/absorbable collagen sponge (ACS) group [BMP-2(Y), n=6]; (3) aged autologous iliac crest bone group [ICBG(O), n=6]; aged rhBMP-2/ACS group [BMP-2(O), n=6]. All were underwent posterolateral fusion in same day. rhBMP-2 and autologous iliac crest bone was implant bilateral LS-L6 intertransverse processes, respectively. Half of the rabbits were sacrificed at 3.6 weeks following surgery, respectively. The results were assessed by manual palpation, radiographs, computed tomographic scans (3D) and histology.

RESULTSSix weeks after surgery, radiography, computed tomography and histology indicated the different result in healing in the posterolateral fusion using rhBMP-2 compared to ICBG (P < 0.05). Aged BMP-2 group showed significantly higher fusion rates than Aged ICBG group.

CONCLUSIONThis study demonstrated rhBMP-2 can increase the posterolateral fusion rate and new bone quality in aged rabbitss than autograft, it may take the place of ICBG. But its role is effected by age.

Aging ; Animals ; Bone Morphogenetic Protein 2 ; pharmacology ; Female ; Humans ; Palpation ; Rabbits ; Recombinant Proteins ; pharmacology ; Spinal Cord ; drug effects ; pathology ; surgery ; transplantation ; Spinal Fusion ; Tomography, X-Ray Computed ; Transplantation, Autologous

Objective: To explore the related factors and working way of adolescent injury,and to provide a basis for the effective prevention and intervention of adolescent injury. Methods: The framework of the questionnaire in this study was developed based on the Social Ecology Model. A cross-sectional survey was conducted on a valid sample of 4 309 students from 8 junior high schools and 8 senior high schools in Beijing and Zhongshan city respectively, using stratified random cluster sampling method. Students from grade 7 to grade 12 were invited to participate and investigated with injury prevalence. Results: The incidence of adolescent injury by person and by person-time was 15.53% and 22.49% respectively, and there were differences by sex, age and regions(χ2=15.92，11.45，20.33，P<0.05). The occurrence of adolescent injury was affected by adolescent psychological behavior and social environment through different underlying pathways. The intrapersonal factors and perception of environmental safety showed direct effects on the adolescents’ injuries (effect size was 0.29 and 0.05 respectively, P<0.05). Conclusion Adolescent injury is associated with diverse factors and pathways in a synergistic and complex manner, suggesting that a three-dimensional and diverse strategy should be taken to intervene the injures.

OBJECTIVETo construct an apparatus for the oxygen uptake measurement of rats exposed to hypobaric hypoxia at different simulated altitude.

METHODSThe capacity of this apparatus was about 0.01 m3. It included animal experimental cabin, reference cabin, altimeter, altitude vertical velocity indicator, pressure difference inductor and oxygen compensator, low scale manometer, soda lime and calcium chloride, small fan, thermometer, circulating water system and vacuum pump. The oxygen uptake of the rats at 6 000 m, 4 000 m and 1 000 m simulated altitude was measured using this apparatus.

RESULTSThe oxygen uptake of the rats at 50 m, 4 000 m and 6 000 m simulated altitude was (24.4 +/- 2.1), (10.8 +/- 2.0) and (8.8 +/- 1.6) ml O2/(kg x min) respectively (average +/- s, n = 10). The oxygen uptake decreased as altitude increased.

CONCLUSIONThis apparatus can be used to measure the oxygen uptake of the rats at different simulated altitude.

Altitude ; Altitude Sickness ; physiopathology ; Animals ; Computer Simulation ; Equipment and Supplies ; Hypoxia ; physiopathology ; Male ; Oxygen ; metabolism ; Oxygen Consumption ; physiology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo determine the level of hyaluronic acid (HA) in serum of patients with oral and maxillofacial malignancy and to investigate the correlation between the levels of serum HA and stage of the malignant lesions and treatment response.

METHODS44 patients with oral and maxillofacial malignancy were analyzed and 24 healthy individuals served as controls. Venous blood was collected from the patients before treatment and the healthy individuals. One week after therapy, venous blood were collected in 24 patients once again. Serum levels of HA were measured with quantitative radioimmunoassay (RIA).

RESULTSBefore treatment, the serum HA concentration in patients with oral and maxillofacial malignancy was significantly higher than that of the controls (P < 0.05). Also, the serum HA concentration in patients with OSCC was significantly higher than that of the controls (P < 0.05). No difference was noted in serum HA concentration between patients with salivary ACC and the control group (P > 0.05). The serum HA concentration of patients in stage III and IV was significantly higher than that of patients in stage I and II (P < 0.05). Serum HA levels decreased in patients after a complete treatment, but the difference was not significant (P > 0.05).

CONCLUSIONSerum levels of HA may be useful in diagnosis of OSCC and was associated with clinical stages in patients with oral and maxillofacial malignancy. However, it may not be contributory to monitoring treatment response in patients with oral and maxillofacial malignancy.

Case-Control Studies ; Humans ; Hyaluronic Acid ; blood ; Mouth Neoplasms ; blood ; Neoplasm Staging

OBJECTIVETo assess referral cases for root canal therapy to provide clinical evidence with establishment of referral system.

METHODSA questionnaire was designed to collect 312 cases (355 teeth) referred to Department of Conservative Dentistry and Endodontics, West China School of Stomatology, Sichuan University for root canal therapy from April to June in 2011. The questionnaire consisted of questions such as age, gender, occupation, general disease and medical histories of patients, sources. Difficulty of treatment before therapy and reasons for referral were evaluated.

RESULTSIn 355 referral teeth, the most were mandibular first molars (17%), the greatest percentage of reasons were calcified root canals (30%), the second was root canal retreatment (24%). 72% of teeth belong to the complicated difficulty (Class III), while 7% were listed as the uncomplicated difficulty (Class I). No significantly difference from different sources was found (P = 0.9).

CONCLUSIONEstablishment of referral system needs cooperation with every dentist. Difficulty of cases for root canal therapy before treatment should be first evaluated to treat or to refer. Referral cases for root canal therapy should be treated by endodontist of corresponding level according to the difficulty.

China ; Dental Pulp Cavity ; Endodontics ; Humans ; Molar ; Referral and Consultation ; Retreatment ; Root Canal Therapy

OBJECTIVETo observe the effect of acupuncture at the whole points of Hand Jueyin pericardium meridian on the amplitude of low frequency fluctuations (ALFF) of healthy people in resting state (R1) functional magnetic resonance imaging (fMRI).

METHODSTotally 16 healthy subjects received structure scan of T1 and T2. Then two fMRI scans were conducted for each participant. fMRI included the resting-state scan (R1; the scanning time was 8 min 6 s), the stimulating-acupoint scan (AP; the scanning time was 8 min 6 s). fMRI data acquisition from structure scanning and function scanning were processed with format conversion and statistical analysis.

RESULTSUnder R1 state, brain regions with activated ALFF signals included bilateral superior frontal gyrus, medial frontal gyrus, middle occipital gyrus, precuneus, superior temporal gyrus, and cingulate gyrus. Under the AP state, brain regions with activated ALFF signals were bilateral superior frontal gyrus, medial frontal gyrus, middle temporal gyrus, left fusiform gyrus, precuneus, posterior cingulate, and declivis. Compared with R1 state, obvious difference of ALFF signal areas of the brain caused by acupuncture at pericardium were: bilateral cuneus, precuneus, left posterior cingulate gyrus, right middle occipital gyrus, and right occipital lingual gyrus.

CONCLUSIONAcupuncture at the whole points of Hand Jueyin pericardium meridian could significantly change inherent activity states of the cerebral cortex, especially in bilateral superior frontal gyrus, medial frontal gyrus, and precuneus.

Acupuncture ; Acupuncture Points ; Brain ; physiology ; Brain Mapping ; Frontal Lobe ; Humans ; Magnetic Resonance Imaging ; methods ; Pericardium