Clinical characteristics of 27 patients with type 1 autoimmune pancreatitis / 中华肝胆外科杂志

Objective To analyze the clinical characteristics of type 1 autoimmune pancreatitis (AIP) in patients.Methods The clinical data of 27 patients with type 1 AIP treated at Fujian Provincial Hospital from January 2012 to October 2018 were retrospectively analyzed.Results There are 25 males (92.6％) and 2 females (7.4％) (ratio 12.5∶1).The age of disease onset was (59.5 ± 14.3) years.The most common presenting symptoms were jaundice and abdominal pain (both 59.3％).The most common complication was IgG4-related sclerosing cholangitis (63.0％).Magnetic Resonance Cholangiopancreatograhpy (MRCP) conducted on 26 patients showed the diffuse type 1 AIP was most common (53.8％),only 2 patients (7.7％) presented with a main pancreatic duct stricture.The pancreatic segment of bile duct narrowing was very common (84.6％),and most patients presented as tapered narrowings (65.4％).Standard glucocorticoid therapy was given to these 27 patients who responded well with clinical and laboratory remissions.Two patients were given maintenance glucocorticoid therapy for a high level of serum IgG4.Conclusions Type 1 AIP can present as a local manifestation of IgG4-related disease.The most common complication is IgG4-related sclerosing cholangitis.Glucocorticoid therapy was effective but some patients required maintenance therapy.

Prognostic value of procalcitonin clearance rate and sequential organ failure assessment score in septic shock children / 中国小儿急救医学

Objective To assess the disease severity and prognosis value by observing the kinetic change of serum procalcitonin(PCT),PCT clearance rate(PCT-C) and Δsequential organ failure assessment (ΔSOFA) score in the patients with septic shock.Methods A single-center observational study was conduc-ted.A total of 274 patients with septic shock admitted into intensive care unit of Hunan Province Children′s Hospital from July 2013 to December 2015 were enrolled.The patients were divided into survival group(n=178) and nonsurvival group(n=96)according to the therapeutic outcome on day 28.The PCT and SOFA scores were estimated within 24 hours when septic shock was diagnosed.PCT-C and ΔSOFA were examined on day 2,day 3,day 5,day 7,day 9 after the septic shock was diagnosed.The diagnostic and predictive per-formance of PCT,PCT-C and ΔSOFA score were assessed by the receiver operating characteristic curve (ROC).Results There were no statistical differences on serum concentrations of PCT at 24 hour,48 hour, 72 hour between two groups.But PCT-C in survival group on day 2,day 3,day 5,day 7,day 9 were signifi-cant higher than those of nonsurvival group.The area under the ROC curve were 0.800(95%CI 0.69~0.91, P=0.000)for PCT-C on day 9,0.980(95%CI 0.78 ~0.95,P<0.000)for ΔSOFA on day 9 and 0.779 (95%CI 0.66 ~0.89,P <0.001)for SOFA score when septic shock was diagnosed. A ROC analysis identified a PCT-C on day 9 more than 38.98%(sensitivity:78.90%,specificity:66.80%) as the most accurate cut-off in predicting death.A ROC analysis identified ΔSOFA score on day 9 less than -0.5(sensi-tivity:89.10%,specificity:91.50%) as the most accurate cut-off in predicting death. Conclusion The increased levels of PCT in patients with septic shock were associated with the poor control of infection and may indicate the deterioration of septic shock,it also can reflect the activity of infection in time. Keeping observing the dynamic change of PCT and analyzing PCT-C are more useful.The PCT-C levels and ΔSOFA score may provide evidence of disease progression and be helpful in risk stratification in patients with septic shock,and lower level of PCT-C and ΔSOFA score may accompany serious infection and predict poor prognosis.

The study of clinical applying continuous hemofiltration in children severe hand-foot-and-mouth disease with cardiopulmonary failure / 中国小儿急救医学

Objective To analyze the clinical value of continuous veno-venous hemofiltration (CVVH) treatment in children with severe hand-foot-and-mouth disease(HFMD) complicated with cardiopulmonary failure,via the prognostic comparison of the general comprehensive treatment and CVVH add-on treatment.Methods Fifty-one cases of severe HFMD with cardiopulmonary failure were divided into a CVVH group (n =19) and a control group(n =32) based on whether CVVH add-on or not.Their physiological and biochemical indicators were recorded and pediatric critical illness score (PCIS) and pediatric risk of mortality score (PRISM Ⅲ) were calculated within 24 hours,when they were diagnosed with neurogenic pulmonary edema (NPE)/pulmonary hemorrhage.Both groups were treated with endotracheal intubation,mechanical ventilation with high PEEP,corticosteroids,ulinastatin,actively lowering the intracranial pressure,fluid resuscitation,milrinone,dopamine and other vasoactive drugs,high-dose intravenous gamma globulin,the CVVH group were added with CVVH treatment(duration ＞ 12 h).Prognosis difference of CVVH add-on treatment after diagnosed with NPE/pulmonary hemorrhage by tracking indicators of the third day.Survival analysis between two groups were compared by 3-day survival rates,7-day survival rates,28-day survival rates and the finally survival rates.Results (1) The overall conditions of two groups were comparable when diagnosed with NPE/pulmonary hemorrhage.PCIS,PRISM Ⅲ,WBC counting,lactic acid,micro-blood sugar,myocardial enzymes and liver enzymes showed no significant difference between two groups.Three days after treatment,WBC and lactic acid decreased,but there was no significant difference (P ＞ 0.05),the remaining indicators had significantly improved in the CVVH group than those in the control group (P ＜ 0.05).(2) The 3-day survival rate,7-day survival rate,28-day survival rate and the finally survival rates in control group and CVVH group were 40.63 ％ vs.84.21％,37.50％ vs.73.68％,25.00％ vs.63.16％,18.75％vs.52.63％,the survival rate in CVVH group were significantly higher(P ＜0.05).(3)The survival curve indicated that the survival time of CVVH group was significantly longer than that of the control group,the median survival time were 17 d and 2 d,respectively,and the difference was statistically significant (P ＜ 0.05).(4)In the CVVH group,15 cases received CVVH after diagnosed with NPE/pulmonary hemorrhage within 12 hours,of which 10 cases(66.67％) ultimately survived,while the other 4 cases received CVVH after 12 h were all end to death,the difference was statistically significant(P ＜ 0.05).Further analysis of the impact of the timing of blood purification on the prognosis of children showed that the mortality rates of children received CVVH within 6 hours,6 to 12 hours,after 12 hours of diagnosis of NPE/pulmonary hemorrhage,were 2/8,3/7,4/4,respectively.Conclusion Continuous hemofiltration can significantly improve the prognosis of children with severe HFMD,and may be preferable to perform in early stage.

A study on the risk and its determinants of HIV transmission by syringe sharing among HIV-positive drug users / 中华预防医学杂志

<p><b>OBJECTIVE</b>To understand the risks and associated factors of HIV transmission by sharing syringes among HIV-positive drug users.</p><p><b>METHOD</b>The survey was conducted among HIV-positive injecting drug users (IDUs-HIV+) who received HIV counseling, testing and treatment in Changsha city Infectious Disease Hospital and Hengyang city No.3 People's Hospital from July 2012 to May 2013 to understand their socio-demographic characteristics, HIV prevalence and syringe sharing. A total of 503 IDUs-HIV+ were involved in and provided the contact list of 2 460 drug users who had the syringe sharing experience over one month with IDUs-HIV+. 420 IDUs-HIV+ among 503 were defined as infection sources due to sharing syringe with at least one drug user. Among them, 234 HIV-negative persons were in control group, and 186 HIV-positive were in cased group. A total of 1 220 drug users were followed up among 2 460 and defined as vulnerable population. The HIV transmission rate was calculated based on the HIV prevalence among vulnerable population. Based on the result of HIV transmission to vulnerable population from 420 infection sources, case-control study and the multivariate logistic regression analysis were adopted to explore the associated factors of HIV transmission among IDUs-HIV+.</p><p><b>RESULTS</b>As the sources of HIV transmission, 420 IDUs-HIV+ had an average duration of (4.5 ± 1.2) years for drug use. As a susceptible population, 1 220 drug users sharing syringes with the 420 IDUs-HIV+ had an average duration of (1.1 ± 0.5) years for drug use. There were 238 HIV-positive persons among 1 220 vulnerable drug users, with a transmission rate of 0.57. In the case-control study, the proportion of male subjects was 87.1% (162/186) in the case group, which was higher than that in the control group (77.8%, 182/234). The proportion of subjects who received support after knowing their HIV infection status was 51.1% (95/186) in the case group, which was lower than that in the control group (79.5%, 186/234). The proportion of subjects sharing syringes every time of using drugs was 47.8% (89/186) in the case group, which was higher than that in the control group (36.8%, 86/234). The proportion of subjects having AIDS awareness was 21.0% (39/186) in the case group, which was lower than that in the control group (64.5%, 151/234); the proportion of subjects having close contact with HIV-positive persons for more than 106 days was 60.2% (112/186) in the case group, which was higher than that in the control group (31.6%, 74/234). The proportion of subjects maintaining the original drug use method after being infected with HIV was 50.5% (94/186) in the case group, which was higher than that in the control group (16.7%, 39/234) (all P values < 0.05). The multivariate logistic regression analysis was carried out to analyse high correlate factors of HIV transmission by sources of transmission, and the AIDS awareness, duration of contact between sources of transmission and vulnerable population, access to support following confirmed HIV infection were protective factors, OR (95% CI) values were 0.155 (0.104-0.262), 0.170 (0.106-0.253), and 0.306 (0.189-0.450), respectively; while the frequency of syringe sharing and continuous drug use after being infected with HIV were risk factors, and the OR (95% CI) values were 3.06 (1.77-5.29), and 3.54 (2.16-5.80), respectively.</p><p><b>CONCLUSION</b>HIV transmission by IDUs-HIV+ might be contained by raising AIDS awareness, providing comprehensive psychological support, conducting needle exchange and methadone maintenance treatment and reducing syringe sharing.</p>

morbidity rate of chronic disease among Chinese rural residents: results from Liuyang cohort

To study the health status and explore the putative risk factors of chronic diseases among a Chinese rural population. Face-to-face interviews were carried out to collect the information of social characteristics, health status and related risk factors of 11,909 families comprised of 49,383 subjects in the rural area of Liuyang, Hunan province during 2007. Chronic disease was diagnosed according to the diagnosis certification from the town clinic or superior level hospital. The morbidity rate of chronic disease among Liuyang rural residents in 2007 was 19.22%. The prevalence of the top 10 chronic disorders was as follows: hypertension: 3.65%; urolithiasis: 1.03%; chronic obstructive pulmonary disease: 0.92%; ischemic heart disease: 0.92%; chronic gastritis: 0.91%; cerebrovascular disease: 0.71%; lumbar disk disease: 0.61%; chronic viral hepatitis: 0.55%; gallstones: 0.54%, and diabetes: 0.54%. Age, gender, educational level, occupation, marital status, type of housing, source of drinking water, smoking, underweight and overweight were factors associated with chronic disease. We also noticed that 14.2% of the residents were underweight and 29.7% are still using unsafe sources of drinking water. The prevalence of chronic disease in Liuyang area was severe both in communicable and noncommunicable chronic disease. Unhealthy lifestyles such as tobacco usage and overweight partially contributed to the high prevalence of chronic disease

Color Doppler ultrasonography in assessment of activity of ulcerative colitis / 中华全科医师杂志

Sixty patients with ulcerative colitis (UC),including 28 males and 32 females were enrolled in the study.Color Doppler ultrasonographic scans were performed and the disease activity was estimated base on the Sourtherland score index (DAI).On the sonography the colon with active inflammatory disease showed bowel wall thickening,alteration of layers structure or even discrimination and increased vascular signals.Using DAI as the gold standard,the sensitivity,specificity,positive predictive value,negative predictive value and accurate rate for ultrasonography in assessment of UC activity were 90.0％ (36/40),75.0％ ( 15/20),87.8％ (36/41),78.9％ (15/19),85.0％ (51/60),respectively.In conclusion,Color Doppler ultrasonography provides a convenient technique for assessment of bowel involvement and inflammatory activity in ulcerative colitis with high sensitivity and accuracy.

Epidemiological study on hemorrhagic fever with renal syndrome in flood areas / 中南大学学报(医学版)

Objective To investigate the infection of hemorrhagic fever with renal syndrome (HFRS) in host animals and inapparent infection of HFRS in general population in Dongting Lake areas after floods. Methods The night trapping method was used to capture rodents. The immunofluorescence assays were used to detect the hantavirus (HV) antigens and antibodies in rodents lung and in the serum of general population. Nonconditional logistic regression was applied to analyze risk factors for inapparent infection with HV. Results In flood region,draw-near flood region and new migration region,rodent density was 6.95%,6.28%, and 8.67%, respectively, and the virus-carrying rate in rodents was 15.07%,9.25%, and 4.47%, respectively. The virus-carrying rat index was the highest in flood region (0.10). Apodemus agrarius was the dominant species. The standardized positive rate of HV antibody in general population from above mentioned regions was 4.49%, 3.11%, and 3.13%, respectively. There was no significant difference among different age or gender groups. The results of logistic regression analysis indicated that people who were involved in construction of water conservancy facilities in winter or practice of rat extermination at home were the principal factors related to inapparent infection with HV. Conclusion The virus-carrying rate in main host animals of HV in the 3 regions is high, whereas the positive rate of HV antibody is low in general population. Comprehensive measures should be taken to prevent and control HFRS, such as reinforcing surveillance of HFRS, strengthening deratization, and preventive inoculation.

comparative analysis of tuberculosis treatment success between Hunan Province of China and Eastern Ghana

To assess the differences in tuberculosis [TB] treatment success between Hunan and Eastern Ghana. The study was a retrospective comparative study using 2005-2006 surveillance data from the Hunan province of China and the Eastern region of Ghana. Data analyzed were from the provincial/regional capital and a randomly selected city of lower economic status. CHI[2] test and Fisher's exact test were used to do general and stratified comparison of treatment success rates within/between the two areas. Multivariate logistic regression was used to analyze the independent effect of explanatory variables on treatment success. Generally, the treatment success rate was significantly higher in Hunan [93.1 vs. 60.7%, p = 0.000]. Stratified analyses showed a similar pattern for almost all the group-specific rates. Key predictors of TB treatment success in Hunan were gender, age group, and type of city of residence whilst in Eastern Ghana treatment success was associated with only age group. Odds ratios for treatment success in Hunan were significantly lower for males [OR = 0.78; 95% CI = 0.63, 0.97], and higher for patients resident in the provincial capital [OR = 1.35; 95% CI = 1.12, 1.62]. In both countries treatment success rates decreased with increasing age. TB treatment success in Hunan was comparatively better than that in Eastern Ghana. Gender, age group, and type of city of residence were the key predictors of treatment success in Hunan whilst in Eastern Ghana age group was the key predictor

Change and influence factors of craving for patients after 6 month methadone maintenance treatment / 中南大学学报(医学版)

OBJECTIVE@#To explore the change and impact factors of craving for heroin in patients after 6 month methadone maintenance treatment (MMT).@*METHODS@#The questionnaire of craving for heroin was used to measure the level of craving for heroin when patients just entered the study and were treated for 6 months. The influence of MMT on craving in patients were analyzed.@*RESULTS@#The total score and score for other factors decreased except the factor "self-control" after MMT. The craving for high dose patients decreased significantly after 6 month treatment (P0.05). The craving degree for heroin in patients with long drug use was higher than that of patients with short drug use. After the treatment, the improvement of craving was more significant for the long drug users.@*CONCLUSION@#MMT can decline the craving for heroin in drug users. Dosage for methadone and gender may be the risk factors of craving change.

Effects of ovariectomy and estradiol on microarchitecture and biomechanical properties in rat vertebrae / 生物医学工程学杂志

This study was aimed at observing the effects of ovariectomy and estradiol on the microarchitecture of cancellous bone and exploring the influence of microarchitectural change on the biomechanical properties. Thirty 6-month-old unmated female SD rats were randomly divided into 3 groups (10 rat each): sham-operated control group (Sham), ovariectomized group (OVX)and Estradiol Benzoate treated group (EBT). All rats were housed in standard environmental conditions. Five months after operation, the rats were sacrificed. The biomechanical properties of the third lumbar vertebras (L3) were measured with compression testing in vitro. Micro-CT scanning was performed on the fourth lumbar vertebras (L4) in vitro. In comparison with the corresponding variables of Sham, the bone volume fraction (BV/TV) and the trabecular number (Tb. N) of OVX were reduced remarkably, and the trabecular separation (Tb. Sp) and the structural model index (SMI) of OVX were enhanced obviously. These facts implicated that the bone trabecular plate-like structure of OVX were decreased. BV/TV, Tb. N and the trabecular thickness (Tb. Th) of EBT were greater than those of OVX. Tb. Sp and SMI of EBT were much smaller than those of OVX. The results of mechanical test showed that the maximum forioe (Fmax), the maximum stress (sigmamax) and the elastic modeulus (E) of the lumbar vertebral cancellous bone of OVX were declined sharply, while the aforesaid biomechanical index of EBT was improved distinctly. The performance of three-dimensional micro-CT and the mechanical testing to assess microarchitecture of cancellous bone are useful for evaluating the state of osteoporosis and the antiosteoporotic effect of agents.

A new three-point bending test for bone biomechanical properties of rat's tibia / 生物医学工程学杂志

In this study, we compared the three-point bending test of the metaphyseal tibia versus the three-point bending test of the diaphysial tibia in rats. Twenty 6-month-old female Sprague-Dawley rats were randomly divided into the ovariectomized (OVX) group and the sham-operated (Sham) group. All rats were housed in standard environmental conditions. Five months after operation, all rats were sacrificed by depletion method. All left tibia were removed for the three-point bending test. The changes of mechanical parameters were examined by the three-point bending test of the metaphyseal tibia and by that of the diaphysial tibia. Elastic, Maximum Load, Maximum Stress, Failure Load, and Failure Stress of the metaphyseal tibia were much lower in OVX rats than in Sham rats. However, there was no statistically significant difference in all of the mechanical parameters of the diaphysial tibia between the OVX group and the Sham group. The new three-point bending test of the metaphyseal tibia is much more sensitive and useful as compared with the test of the diaphysial tibia in evaluating the changes of mechanical properties of tibia in osteoporotic rats.

Biomechanical evaluation of titanium mesh with anterior plate fixation in anterior cervical decompression / 生物医学工程学杂志

We have made a biomechanical evaluation of titanium mesh with anterior plate fixation in anterior cervical decompression. Six fresh cervical spine specimens (C3-7) of young cadavers were used in the biomechanical test. Subtotal vertebrectomy was performed on C5, C5-6 and C4-6. We accomplished two constructions: (1) bone graft; (2) titanium mesh with anterior plate fixation. Then their biomechanic stabilities were tested in all groups and compared with those of intact specimens. We found that titanium mesh with anterior plate fixation improved the stability of the unstable spine, showing a significant difference when compared with that of the intact group (P < 0.05). The anterior cervical interbody fusion by bone graft and the titanium mesh implantation is stabler than the intact cervical sample, and the stability decreases with the increase in number of cervical segment.

Development of a functional mandibular model / 生物医学工程学杂志

This study was conducted to establish a functional mandibular biomechanical model for use in the follow-up biomechanical study of the integrated and fractured mandible. The integrated and dry human mandible was used, and the corresponding maxilla and cranial base was duplicated by resin and plaster. 2-mm silicon rubber was used for simulation of the temporomandibular joint (TMJ) disc. A simulated TMJ and physiological mandibular model was developed by four pairs of muscular loadings (Masseter= 180 N, Temporalis = 190 N, Medial Pterygoideus = 120 N, Lateral Pterygoideus = 40 N) in each muscular center, and the functional loading corresponding with physiological condition was reflected and simulated more realistically when compared with that of the previously reported mandibular models which were developed by occlusion loading or by only one pair of muscles loading. In summary, we have established a functional mandibular model which can be used to analyze the biomechanical behavior in various functional conditions.

Testing of anisotropic modulus and fluid characteristic of Chinese femur and tibia / 生物医学工程学杂志

The tension moduls and compression modulus of Chinese tibia and femur of male in three different directions, namely axial, circumferential and radial directions, were tested in our experiments. The measured compression moduli are 5.8 +/- 0.34, 3.4 +/- 0.17, 2.1 +/- 0.18 GPa respectively for femur, and 6.1 +/- 0.36, 3.5 +/- 0.17, 2.1 +/- 0.18 GPa respectively for tibia; the measured tension moduli are 15.6 +/- 1.21, 9.8 +/- 0.73, 5.4 +/- 0.52 GPa respectively for femur, and 16.7 +/- 1.09, 10.3 +/- 0.70, 5.6 +/- 0.49 GPa respectively for tibia. The tension and compression ultimate strengths of femur and tibia were tested, too. The measured compression ultimate strengths are 150 +/- 9.3, 111 +/- 6.5, 110 +/- 7.1 MPa respectively for femur, and 191 +/- 12.3, 140 +/- 6.3, 123 +/- 8.3 MPa respectively for tibia; the measured tension ultimate strengths are 115 +/- 9.6, 82 +/- 6.8, 78 +/- 7.3 MPa respectively for femur, and 143 +/- 8.7, 110 +/- 8.3, 97 +/- 6.4 MPa respectively for tibia. Furthermore, the stress-relaxation experiments were conducted. The relation between loading and time during the experiments were obtained by the method of curve fitting. They meet the logarithm function: F = A * B(log t); A is the initial load, and B is the fitting material parameter. For femur, B is equal to 0.985; for tibia, B is equal to 0.987.

The effect of mechanical strain on proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells from rats / 生物医学工程学杂志

In order to investigate the effects of cyclic biaxial mechanical strain on proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (MSCs)from rats. The MSCs were isolated from bone marrow in the 9-month-old female Sprague-Dawley rats by a density gradient method. After the third passage,1 x 10(5) cells were seeded on the flexible silicone membrane in the cyclic biaxial mechanical strain unit. The amplitude of mechanical strain applied to the cells were 4000 microstrain, at a frequency of one hertz (1 Hz), for periods of 3 repetitions of 2 hours' mechanical strain and a break of 2 hours. The osteoblastic marker such as osteopontin (OPN),alkaline phosphatease (ALP), osteocalcin (OCN), type I collagen (Col I) were detected by RT-PCR. The proliferation of all cells were studied with Flow Cytometry (FCM). ALP and OPN levels significantly increased in the mechanical strained groups and reached the top at 3th day after mechanical strain. COL I level was increase only at 3th day after mechanical strain, and the change of OCN was not obvious in every group. The proliferation index of the medchanical strained groups was increased, compared with the control. These results showed that mechanical strain can improve MSCs proliferation and make MSCs differentiate to osteoblast.

The effect of mechanical stimulation on the proliferation and synthetic function of osteoblasts from osteoporotic rat / 生物医学工程学杂志

The purpose of this paper is to investigate that the effect of cyclic biaxial mechanical strain on proliferation and synthetic function in the osteoblasts isolated from 3 month-old normal female Sprague-Dawley (SD) rats and osteoporotic rats. The osteoblasts were cultured in F-12 medium contained with 10% fetal bovine serum (FBC) and grown to subconfluency in Flexercell apparatus in a humidified incubator with 5% CO2 and 95% air at 37 degrees C. Mechanical strain was applied to the cells for periods of 30 min, 2, 4 and 8 hours every day,lasting 2 days. The amplitude of mechanical strain applied to the cells were 400, 1000 and 4000 microm strain respectively, at a frequency of one hertz (1 H). Unstrained cells were used as control. The results showed that proliferation activity of osteoblast in osteoporotic rats are higher than that in normal rats without mechanical strain the mechanical strain can elevate the proliferation activity and the synthetic function of osteoblast from normal rats at 400, 1000 microm strain. However, the mechanical strain increased significantly the proliferation in the osteoblasts and suppressed obviously the synthetic function in the osteoblasts at 4000 microm strain. The mechanical strain don't affect the proliferation activity and the synthetic function of osteoblast from osteoporotic rats at 400 microm strain. The mechanical strain decrease the proliferation activity of osteoblast from osteoporotic rats at 1000 microm strain. The mechanical strain can elevate the proliferation activity and the synthetic function of osteoblast from osteoporotic rats at 4000 microm strain. In our study, the reaction of the osteoblasts from normal rats and osteoporotic rats to the mechanical stimulation suggested that there are more highly sensitive to the mechanical stimulation in the osteoblasts from normal rats than that from osteoporotic rats.

Biomechanical study of medical hard tissue adhesive bonding butterfly fracture fragment in middle part of fresh human tibia / 生物医学工程学杂志

A medical hard tissue adhesive, octyl-a-cyanoacrylate, was tested in 6 fresh human tibiae. A 90 degrees butter-fly fracture fragment was made in the middle part of tibia by bandsaw. The compressive stress, torsional stress and angular deflection were assessed before and after osteoectomy respectively. After adhesive bonding, the compressive stress, torsional stress and angular deflection were tested again. The butterfly fracture fagment decreased the bending strength, torsion strength, yielding strength of tibia bone. In torsion test, the torque of tibia before osteoectomy is greater than bonded tibia, the bonded tibia is greater than that of the unbonded tibia. In compression test, before adhesive bonding broken, the compressive curve slope of tibia before osteoectomy is greater than that of bonded tibia, the bonded tibia is greater than that of the unbonded tibia. In angular deflection test before adhesive bonding of broken,the curve slope of tibia before osteoectomy is not different from that of bonded tibia (P>0.05), the slope the bonded tibia is greater than the slope of unbonded tibia(P<0.05). The elastic modulus, rigidity coefficient and moment of area inertia show no statistical difference between the bonded tibia and intact tibia. The used of medical hard tissue adhesive to bond the fracture fragment could improve the bending strength, torsion strength, yielding strength of tibia bone. In operation, it can reduce the soft tissue injury when the fracture fragment is being fixed, and this will benefit bone healing.

The effect of cryotreat on the wear resistance of the medium melting-point castable alloy / 华西口腔医学杂志

<p><b>OBJECTIVE</b>The purpose of this study was to introduce cryotreat technique into prosthetic dentistry by investigating the wear resistance changes of SDA-II medium melting-point castable alloy before and after cryotreat.</p><p><b>METHODS</b>15 samples were divided into three groups, i.e. control group, cryotreat group, cryotreated plus post-cryogenic treat group. Weight loss measurement was used to examine the wear resistance.</p><p><b>RESULTS</b>For SDA-II medium melting-point castable alloy, cryotreat effectively improved its wearing resistance; so far as the wear resistance was concerned, the post-cryogenic treatment was unnecessary.</p><p><b>CONCLUSION</b>The results obtained above suggest that cryotreat was an effective method in enhancing the wear resistance of SDA-II medium melting-point castable alloy.</p>

The effect of mechanical stimulation on the expression of alpha 2, beta 1, beta 3 integrins and the proliferation, synthetic function in rat osteoblasts / 生物医学工程学杂志

The purpose of this paper is to investigate the probable molecular mechanism in mechano-transduction of the regulation of integrins and the effects of cyclic biaxial mechanical strain on proliferation and synthetic function in the osteoblasts isolated from 3-month-old female Sprague-Dawley (SD) rats. The osteoblasts were cultured in F-12 medium contained with 10% fetal bovine serum(FBS) and grown to subconfluency in Flexercell type I dishes in a humidified incubator with 5% CO2 and 95% air at 37 degrees C. Mechanical strains were applied to the cells for periods of 30 min, 2, 4 and 8 hours every day, lasting 2 days. The amplitude of mechanical strain applied to the cells were 400, 1,000 and 4,000 mu strain respectively, at a frequency of one hertz(1 Hz). Unstrained cells were used as control. The expression of integrins alpha 2, beta 1, beta 3 on the membrane of osteoblasts and proliferation activity of osteoblasts were studied with Flow Cytometry(FCM). The content of osteocalcin, carboxyterminal propeptide of type-I procollage(PICP), total protein secreted by osteoblastes were detected with the isotope labelling method. The results showed that there are actual expressions of integrins alpha 2, beta 1, beta 3 on the membrane of osteoblasts without mechanical strain and that the expression of integrins beta 1 is highest. The mechanical strain increased the expression of integrins alpha 2, beta 1, beta 3 on the membrane of osteoblasts, but the strain-related up-regulation of expression of integrins alpha 2, beta 1, beta 3 are different in various amplitude and different duration of mechanical stains. The up-regulation of expression of integrins beta 3 is most sensitive to mechanical strain. The up-regulation of expression of integrins alpha 2, beta 1, beta 3 is higher at 4,000 mu strain than at 400, 1,000 mu strain. The mechanical strain can elevate the proliferation activity and the synthetic function of osteoblast at 400, 1,000 mu strain. However, the mechanical strain increased significant the proliferation in the osteoblasts and suppressed obviously the synthetic function in the osteoblasts. In the present study, the reaction of the osteoblasts in 3 month-old rat to the mechanical stimulation suggested that 1) expressions of integrins alpha 2, beta 1, beta 3 were increased in a amplitude of strain-dependent manner; 2) the changes of expression of integrins alpha 2, beta 1, beta 3 relate close to the changes of the proliferation and synthetic function of the osteoblasts. Low amplitude of strain can increase the proliferation and the synthetic function of the osteoblasts along with up-regulation of expression of integrins alpha 2, beta 1, beta 3; while higher amplitude of strain elevated significantly the proliferation of osteoblasts and suppressed obviously the synthetic function of the osteoblasts along with up-regulation of expression of integrins alpha 2, beta 1, beta 3. The amplitude of 4,000 mu strain is an optimal amplitude as stimulus for up-regulation of expression of integrins alpha 2, beta 1, beta 3 on the membrane of osteoblasts and increase the proliferation activity, but decrease the synthetic function of osteoblasts in the present study. Accordingly it indicates that integrins have a important role in regulation of signal transduction pathway in osteoblasts as a result of mechanical strain.

A system applying cyclic biaxial mechanical strain to cultured cells / 生物医学工程学杂志

To study the response of cultured cells to the cyclical biaxial biomechanical strain, a system was made according to the principle of Winston. The system was made of culture dish, pressure cavity and step motor. The culture dishes were made of polymethyl methacrylate and the bottom of the culture dishes were made of silicone rubber membrane. When the diameter of the silicone rubber tube and the distance between rollers and curvilinear plate changed, the pressure in the pressure cavity changed and the strain of the membrane changed from 0 to 4%. When the roll of the step motor changed, the frequency of the strain changed from 0.1 to 5 Hz.