Finite element analysis of different intramedullary fixation methods for the treatment of senile pubic ramus fractures / 中国骨伤

OBJECTIVE@#To evaluate the biomechanical stability of elastic intramedullary nail in the treatment of pubic ramus fractures by finite element analysis, and to compare the stability of elastic intramedullary nail with cannulated screw intramedullary fixation.@*METHODS@#The CT data of the pelvis of a volunteer were selected, and the three-dimensional model of the pelvis was reconstructed by reverse engineering software and the fracture of the pubic ramus fractures was simulated by osteotomy. The hollow nail model, single elastic nail model and double elastic nailmodel were assembled with different implants respectively. The mesh division, material assignment loading and other steps were carried out in the ANSYS software, and then the calculation was submitted.@*RESULTS@#The overall displacement of the pelvis of the elastic nail model was smaller than that of the cannulated screw model, in which the double elastic nail model had the smallest overall displacement, but the cannulated screw model had the smallest plant displacement and the single elastic nail model had the largest plant displacement. Although the stress of cannulated screw was small, there was obvious stress concentration, the stress of elastic nail was large, but there was no obvious stress concentration, especially the stress distribution of double elastic nail was more uniform and the overall stress of pelvis was the smallest.@*CONCLUSION@#All the three fixation methods can effectively improve the stability of the anterior ring of the pelvis. Among them, there is no significant difference in the overall biomechanical propertiesof hollow nail fixation and double elastic nail fixation, which is better than that of single elastic nail fixation. Elastic nail fixation has the advantages of minimally invasive surgery and good biomechanical stability, so it can be used as a better surgical method for the treatment of pubic ramus fractures.

Finite element simulation of femoral neck fracture in osteoporotic rats / 医学研究生学报

Objective There are few reports on the establishment of the finite element model of the rat femur in China, and even none on the finite element analysis of rat hip fracture. This study aimed to build a finite element model of osteoporotic rat proximal femoral fracture base on fracture mechanics. Methods We collected the CT imaging data on the femur of a healthy adult SD rat and established a preliminary three-dimensional finite element model of the rat femur. We also constructed a finite element model of femoral neck fracture in an osteoporotic rat by mesh generation, defining the material properties, setting interfacial properties and failure parameters, and loading. Then we measured the crack moment, von Mises, shear stress, stress, strains, displacement, and the starting point of fracture. Results The von Mises of stress showed that the crack moment was 0.109980s and the maximum stress and shear stress were mainly distributed on the medial inferior and lateral superior of the femoral neck when damage started, with the maximum stress of 367.9 Mpa and the maximum shear stress of 200.4 Mpa. The maximum strains was 1.2%, which was consistent with the routes of crack extension and extended from the medial inferior to the superior. The maximum displacement was 1.6 mm, mainly distributed on the proximal femoral, concentrated at the femoral head, and a displaced femoral neck model was simulated finally. Conclusion The finite element simulation model of femoral neck fracture in osteoporotic rats was successfully established, which can provide a new method for biomechanical studies in animal experiments.

Impact of intertrochanteric cortical thickness on hip fracture types under dynamic load: A finite element analysis / 医学研究生学报

Objective The influence of intertrochanteric cortical thickness on hip fracture can be investigated by the finite element method (FEM), but few dynamic FEMs have been established to manifest the extension of the crack. This study aimed to investigate the influence of intertrochanteric cortical thickness on the proximal femoral fracture types by FEM.Methods We recruited a healthy male volunteer from the Department of Traumatic Orthopedics, the First Affiliated Hospital of Guangzhou University of Chinese Medicine in October 2017, established a 3-dimention model, and reconstructed thick, middle and thin intertrochanteric cortex proximal femur models by meshing, defining material properties and setting boundary conditions. We measured the crack moment and von Mises stress, distribution of the fracture line, and the time-stress curves of the earliest damage element.Results Fracture occurred the earliest in the thin-cortex femur model but the latest in the thick one. The von Mises stress contour plot showed that, when damage started, the stress was concentrated on the posterior femoral neck and intertrochanteric region, extending to the posterior inferior part of the lesser trochanter in all the three models and, with the decline of the intertrochanteric cortex thickness, the concentration of the von Mises stress gradually narrowed down and shifted to the intertrochanteric region. The narrowing of the von Mises stress was the most obvious in the thin-cortex model, mainly distributed on the junction of the basal femoral neck and the intertrochanteric region. With the thinning of the cortex, the lesser trochanter became the region of stress concentration. The time-stress curves showed that fracture occurred the earliest in the thin-cortex model, with the maximum stress of 51.6 Mpa, but the latest in the thick-cortex model, with the maximum stress of 96.4 Mpa, and the maximum stress was 89.7 Mpa in the middle cortex model.Conclusion The thickness of the intertrochanteric cortex may be a determinant in the types of hip fracture.

Finite element analysis of intertrochanteric fractures in older adults based on Hypermesh 14.0 and LS-DYNA software / 中国组织工程研究

BACKGROUND: At present, finite element analysis can be used to judge intertrochanteric fractures, but mostly limited in the distribution of stress. Finite element model of various intertrochanteric fractures has not been reported in detail.OBJECTIVE: To build various types of intertrochanteric fracture models with Hypermesh 14.0 and LS-DYNA software to simulate the falling-induced external force on proximal femur, and to evaluate the effect of models, and to analyze the biomechanical mechanism of intertrochanteric fractures. METHODS: Normal side CT image data of one case of elderly intertrochanteric fracture were collected and imported into Mimics software to establish the proximal femur geometric models, were then analyzed and operated by LZ-DYNA solver after imported into Geomagic studio 2013 and Hypermesh 14.0 for smoothing and meshing. Before analysis, the material parameters were set, the boundary conditions were confirmed, and given the loading parameters. The operating results were checked in Hyper View. RESULTS AND CONCLUSION: (1) The distribution of stress of proximal femur exactly matched to the previous study. EvansⅠtype intertrochanteric fracture model was obtained under continuous shear stresses, and six types of fractures were obtained by adjusting the load. (2) These results manifest that based on the Hypermesh 14.0 and LS-DYNA software, the finite element can well simulate the intertrochanteric fractures, and shear stress plays an important role in intertrochanteric fractures, which can provide experimental basis for the prevention and treatment of intertrochanteric fractures.

Intestinal absorption of the effective components of Schisandra chinensis Baill by rats single-pass perfusion in situ / 药学学报

The aim of the study is to investigate rat intestinal absorption behavior of three main active components, schisandrol A, schisandrin A and schisandrin B in Schisandra chinensis Baill extracts in intestine of rats. With phenol red as the indicator, in situ single pass intestinal perfusion (SPIP) model was used and the concentrations of three main active components in perfusion solution of different intestinal segments (duodenum, jejunum, ileum, and colon) were determined by HPLC in combination with diode array detection. The results showed that the absorption rate constant (Ka) and effective permeability values (Peff) of three main active components in Schisandra chinensis Baill extracts had significant difference (P < 0.05) at different concentrations of perfusion solution, the Ka and Peff first increased and then decreased with the increase of drug concentration, the middle concentration was higher than those of the other two concentrations. The saturate absorption phenomena were observed, and it suggested that the transport mechanisms of three main active components in vivo were similar to active transport or facilitated diffusion. Three active components can be well absorbed in all of the intestinal segments, while duodenum is the best absorption region. The Ka and Peff of three active components in jejunum and ileum had no significant difference (P > 0.05). The absorption of the three active components displayed significant difference (P < 0.05) at different intestinal segments of rats. Schisandrin A had the best absorption in duodenum. The Ka and Peff among three active components were sequenced as follows: schisandrin A > schisandrin B > schisandrol A in other intestinal segments, and there is significant difference (P < 0.05) between them.

Effect of different dynamic mechanical strain on the proliferation and synthetic function of human periodontal ligament fibroblasts in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the changes in the proliferation and synthetic function of human periodontal ligament fibroblasts (HPDLF) in response to dynamic mechanical strains of different modes, magnitudes and durations.</p><p><b>METHODS</b>Using a 4-point bending system, the effect of dynamic mechanical strains of different modes, magnitudes and durations on the proliferation of HPDLF was investigated by analyzing the cell cycle changes with flow cytometry (FCM), and the total protein level and the activity of alkaline phosphatase (ALP) in HPDLF were assayed by quantitative analysis.</p><p><b>RESULTS</b>The percentage of G(0)/G(1) cell decreased, S phase cells increased, and the proliferation index (PI), total protein level and activity of ALP were augmented significantly in response to dynamic mechanical micro-strains. These changes showed close correlations to the magnitude and duration of the strain. The mode of strain caused significant changes in G(0)/G(1), S, and G(2)/M phase cell percentages as well as the PI, total protein level and ALP activity of the cells. In the gradient strain group, the cell proliferation activity, total protein level and ALP activity were obviously higher than those in 1000 and 4000 microstrain groups.</p><p><b>CONCLUSION</b>The changes in the proliferation and synthetic function of HPDLF are closely correlated to the mode, magnitude and duration of the strains.</p>

Mutations in NPHS2 in familial steroid-resistant nephrotic syndrome in Southern Chinese Han ethnic group / 中华儿科杂志

<p><b>OBJECTIVE</b>Mutations in NPHS2 mapped to 1q25-q31 and encoding podocin, which is exclusively expressed in glomerular podocytes, are responsible for autosomal recessive familial steroid-resistant nephrotic syndrome (SRNS) with minor glomerular abnormalities or focal segmental glomerulosclerosis. Different groups from European and North American countries have screened NPHS2 mutations in familial SRNS with recessive inheritance, documenting a mutation detection rate of 45% - 55% in families. This study aimed to examine mutations in the NPHS2 gene in Southern Chinese Han ethnic group patients with familial SRNS.</p><p><b>METHODS</b>Genomic DNA from 3 probands from Southern Chinese Han families with autosomal recessive SRNS, and their siblings and parents was isolated and analyzed for all eight exons, exon-intron boundaries and promoter of NPHS2 using the polymerase chain reaction and direct sequencing.</p><p><b>RESULTS</b>No mutation of NPHS2 in all eight exons and exon-intron boundaries was identified in the 3 probands. However, a polymorphism of 954T > C in exon 8 was detected in all the 3 probands and some controls, and 5 variants of NPHS2 promoter, -1709G > A, -1000A > T, -670C > T, -116C > T and -51G > T, were identified in some patients and controls, indicating that these variants are polymorphisms. One heterozygous variant of NPHS2 promoter, -1715A > G, was also identified in one proband and her mother whose urinalyses were normal, whereas it was not found in any of the 50 controls. There was no significant difference in the allelic frequencies of -1709G > A, -1000A > T, -670C > T, -116C > T and -51G > T polymorphisms between the patients and controls.</p><p><b>CONCLUSION</b>NPHS2 mutations are not a major cause of familial steroid-resistant nephrotic syndrome in Southern Chinese Han ethnic group included in the study.</p>

Research of morphology for the toothmark in pocket limb / 华西口腔医学杂志

<p><b>OBJECTIVE</b>The purpose of this study was to observe the morphological changes of toothmarks in pocket limbs and to explore the durative development of bitemarks.</p><p><b>METHODS</b>Firstly a toothmark model was established by using a universal testing machine and a self-made incisor nod which was pressed particularly on pocket limbs. The changes of toothmarks were observed on alive and dead animals with time elapsing. The scopes of bruise and inden were analyzed by soft on digital photos. The depth data of inden were collected by three dimensional laser measurement.</p><p><b>RESULTS</b>The changes in the alive group were faster than that in dead group. There was no obvious fadeaway of bruise during 24 h. The scopes of inden were decreased remarkably in 1 h, while the decrease slowed down in the following hours.</p><p><b>CONCLUSION</b>The changes of indent are fast in pocket limb. It implies that bitemark evidence should be collected as fast as possible in cases.</p>

Regulation of integrin beta1 mRNA expression by mechanical stress in human periodontal ligament fibroblasts / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of different kinds of mechanical stress on the mRNA expression of integrin beta1 subunit in cultured human periodontal ligament fibroblasts (hPDLF).</p><p><b>METHODS</b>To scalp and remove the periodontal ligament attached to the mid-third part of the fresh root of young premolars extracted for the cause of orthodontics. Cultured hPDLF by the method of digesting by I-type collagenase combining with tissue adhering. Then hPDLF was isolated and purified by cells passage. The sixth passage's cells were selected to be loaded. A new cyclic strain loading apparatus. Forcel four point bending device was used for mechanically loading. Cells were loaded by three levels (1000, 2000, 4000 microstrain) of tensional and compressive forces and collected at different times (0, 0.5, 1, 4, 8, 12 h) course after strain loading. The quantity of integrin beta1 mRNA in every group was analyzed by means of quantitative real-time PCR with the special primers of up- and down-regulated genes.</p><p><b>RESULTS</b>Dynamic mechanical forces down-regulated the expression of integrin beta1 subunit mRNA in hPDLF and the difference in groups by different magnitude, different kinds, and different time of mechanical forces loading were statistically significant. The stronger stimulated forces, the more down-regulated expression. Compression down-regulated the expression of integrin beta1 subunit mRNA more than tension did.</p><p><b>CONCLUSION</b>Dynamic mechanical forces could regulate the expression of integrin beta1 subunit mRNA. The difference among all the groups by different magnitudes, different kinds, and different time of mechanical forces loading were statistically significant.</p>

Neuroprotective effects of topiramate and folic acid on young rats with kindling-induced epilepsy / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the neuroprotective effects of topiramate (TPM) alone or together with folic acid (FA) on young rats with kindling-induced epilepsy.</p><p><b>METHODS</b>Rat models of epilepsy were prepared by pentylenetetrazol (PTZ)-induced kindling. Seventy-two 3-week-old male Wistar rats were randomly divided into 6 groups: four TPM-treated epilepsy groups (TPM 20, 40 or 80 mg/kg/d and TPM 40 mg/kg/d + FA 5 mg/kg/d), a positive control group (untreated epilepsy group) and a negative control group (normal control group). After two months of administration, behaviors of the rats were recorded; serum levels of neuron-specific enolase (NSE) were measured using ELISA; pathological changes in the hippocampus were observed.</p><p><b>RESULTS</b>The frequency of convulsion seizures in the 20, 40 and 80 mg TPM treatment and TPM+FA groups was 44.7 +/- 2.9, 44.3 +/- 3.1, 42.7 +/- 3.2, and 40.8 +/- 3.7 respectively, which were significantly lower than that in the positive control group (48.4 +/- 3.7) (P <0.01). Twenty, forty and eighty mg TPM treatment and TPM+FA treatment significantly reduced NSE levels from 35.71 +/- 5.97 microg/L of the control group to 27.40+/- 6.40, 24.79 +/- 6.22, 21.47 +/- 6.87 and 22.55 +/- 7.02 microg/L respectively (P <0.05). Neuronal apoptosis in the CA3 and CA1 regions were alleviated in the four TPM treatment groups compared with positive control. The number of necrotic neurons was progressively reduced with the increased dose of TPM. The 40 mg TPM+FA treatment group showed less necrotic neurons in the CA3 and CA1 regions than the 40 mg TPM alone treatment group.</p><p><b>CONCLUSIONS</b>TPM has protective effects against epilepsy-induced neuronal damage. The effect is dose-dependent. A combination of TPM and FA can produce a synergistic effect.</p>

Regulation of collagen type I and fibronectin mRNA expression by mechanical stress in cultured human periodontal ligament fibroblasts / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of different dynamic tensional and compressive stress on the mRNA expression of collagen type I and fibronectin in cultured human periodontal ligament fibroblasts (hPDLF), and explore the regularity of functional change in hPDLF.</p><p><b>METHODS</b>A new cyclic strain loading apparatus was used for mechanically loading. Cells cultured in vitro were loaded with three levels (1000 microstrain, 2000 microstrain, 4000 microstrain) of tensional and compressive forces and collected at different time (0 h, 0.5 h, 1 h, 4 h, 8 h,12 h) course after strain loading. The quantity of collagen type I and fibronectin mRNA was analyzed by means of quantitative real-time PCR with special primers of up- and down-regulated genes. Data were analyzed using SPSS version 10.0 software.</p><p><b>RESULTS</b>Different magnitude and different kinds of mechanical forces as well as the force application time significantly changed the expression of collagen type I and fibronectin mRNA in hPDLF.</p><p><b>CONCLUSIONS</b>Dynamic mechanical forces could regulate the expression of collagen type I and fibronectin mRNA in hPDLF. Collagen type I and fibronectin participated in the mechanical signal transduction in human periodontal ligament fibroblasts.</p>

Targeted blockage of RNA binding protein E2 by decoy RNA induces the granulocytic differentiation of K562 cells / 中华血液学杂志

<p><b>OBJECTIVE</b>To use a decoy RNA targeted blockage of the RNA binding protein E2 (hnRNP E2) resulting in the CCAAT/enhancer-binding protein alpha (C/EBP alpha) gene's abnormal translation and investigate its effect on the granulocytic differentiation of K562 cells and the probable molecular mechanism.</p><p><b>METHODS</b>The hnRNP E2 decoy RNA expression plasmid was constructed and transfected into K562 cells with cationic liposome, and stable expression cells were obtained by G418 selection. The changes of C/EBP alpha and granulocyte colony-stimulating factor receptor (G-CSFR) gene expression were detected by RT-PCR and Western blot. The morphologic changes were observed after Wright-Giemsa staining. The expression of granulocytic differentiation antigens CD13 and CD15 was studied by immunocytochemistry.</p><p><b>RESULTS</b>The stably expressed pG cells were obtained. Its C/EBP alpha mRNA level remained unchanged, while 42kD-C/EBP alpha protein expression was increased by (49.7 +/- 5.5)% (P < 0.05); and G-CSFR mRNA was increased by (42.1 +/- 3.6)% (P < .05), and its protein was increased by (37.4 +/- 6.2)% (P < 0.05) compared to that in the K562 control cells. The characteristics of polymorphonuclear neutrophils appeared in pG cells and CD13 and CD15 positive cell ratios were (18.7 +/- 2.5)% and (26.3 +/- 2.9)% respectively.</p><p><b>CONCLUSIONS</b>HnRNP E2 decoy RNA can induce granulocytic differentiation of K562 cells, and G-CSF promotes this effect. The mechanisms may be that decoy RNA specifically blocks hnRNP E2, hence regulates the translation of C/ EBP alpha mRNA, restores the expression of 42kD-C/EBP alpha, and then up-regulates the expression of G-CSFR gene.</p>

Effects of continuous adenosine infusion on pulmonary hypertension in chronically hypoxic rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the effects of continuous subcutaneous adenosine infusion on pulmonary hypertension in chronically hypoxic rats.</p><p><b>METHODS</b>Twenty-four SD rats were randomized into normoxic group, hypoxic group and adenosine-treated hypoxic group. Hypoxic environment was simulated in a chamber filled with 10% oxygen and 90% nitrogen. After 7 days of hypoxia, adenosine were administered subcutaneously in the rats in adenosine-treated group at the rate of 100 microg kg(-1) min(-1) via an Alzet micro-osmotic pump for 14 days, while the pumps in the other two groups contained normal saline. After 21 days of hypoxia, pulmonary artery pressure and tail-cuff blood pressure were measured, with the plasma rennin activity (RA), angiotensin II (AngII), endothelin (ET)-1, and nitric oxide (NO) determined. Inducible nitric oxide synthase (iNOS) expression in the pulmonary artery of the rats was detected using immunohistochemical method.</p><p><b>RESULTS</b>The mean pulmonary artery pressure (mPAP) was significantly higher in the hypoxic group than that in the normoxic group (P<0.01) and in the adenosine-treated group (P<0.01). Plasma ET-1 was significantly higher but plasma NO significantly lower in the hypoxic group than in the normoxic group (P<0.01) and the adenosine-treated group (P<0.01). iNOS expression in the pulmonary artery was higher in the hypoxic group than in normoxic group (P<0.01), and adenosine significantly increased iNOS expression in comparison with the normoxic and hypoxic groups (P<0.01). Plasma RA and AngII in the hypoxic group were significantly higher than those in the normoxic group (P<0.01) and the adenosine-treated (P<0.01).</p><p><b>CONCLUSION</b>Adenosine administered by continuous subcutaneous infusion alleviates chronically hypoxia-induced pulmonary hypertension in rats, in which rennin angiotensin system, ET-1, and iNOS/NO play a role.</p>

Effect of gilding technique on the element release of beryllium ion from vera bond Ni-Cr-Be alloy / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of gilding technique on the element release from Vera Bond Ni-Cr-Be alloy exposed to artificial saliva.</p><p><b>METHODS</b>To measure the quantity of beryllium ion which was released from common used Ni-Cr porcelain crown (controlling group), polished Ni-Cr porcelain crown (polished group), gilded Ni-Cr porcelain crown (gold-plating group) and gilded Ni-Cr porcelain crown prolonged 50% (gold-plating prolonged 50% group) in artificial saliva after 1 month, 3 months and 6 months by means of ICP-AES. So the effect of released beryllium ion with different treatments and the rule of different times with the same treatment were compared.</p><p><b>RESULTS</b>The quantity of released beryllium ion was statistic significant among different treatments. The quantity of released beryllium ion was gradually increased with the same treatment. At the end of this experiment, it was reached the highest. The speed of released beryllium ion was gradually decreased with the same treatment. At the end of this experiment it was reached the lowest.</p><p><b>CONCLUSION</b>The gilding treatment can decrease the quantity of beryllium ion which released from Ni-Cr porcelain crown, and improve the biocompatibility.</p>

Effect of the thickness of periodontal ligament on the fracture resistance of root and post-core system / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To assess the effect of the thickness of periodontal ligament on the fracture resistance of root and post-core system.</p><p><b>METHODS</b>Forty-five simulated roots in the same length, taper and diameter were made of polymethacrylate (PMMA). Then the wax patterns of post-cores were cast. Soft lining material was used to simulated periodontal ligament. And each specimen was embedded in acrylic resin and then fixed in a special jig on the universal load-testing machine. A compressive load was applied at a 90-degree angle to the long axis of the core until fracture, at a crosshead speed of 1 mm/min. The maximum of load and the displacement were recorded.</p><p><b>RESULTS</b>The mean values of load in root and post-core system were 148.033 N, 161.889 N, 168.667 N, 181.589 N, 194.622 N, and the mean values of displacement were 1.965 mm, 2.837 mm, 3.327 mm, 3.927 mm, 5.326 mm.</p><p><b>CONCLUSION</b>The fracture resistance and displacement of root and post-core system with the same quality and altitude periodontal ligament are associated with the thickness of periodontal ligament when the range of thickness is from 0.2 mm to 1.0 mm.</p>

Application of insertion-type separate post on ceramic restoration of molar residual root and crown with low occlusogingival distance / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the clinical effects of insertion-type separate post and post-crown on ceramic restoration of molar residual root and crown with low occlusogingival distance and large root bifurcation angle.</p><p><b>METHODS</b>19 molar residual roots and crowns with low occlusogingival distance(<3 mm) and large root bifurcation angle were involved in this study. Firstly, the root canals were prepared according to their natural directions without concerning about the common path of insertion. Accurate impression were taken with silicone. Insertion-type separate post and core-ceramic crown were fabricated respectively. Finally, the two parts were cemented together in patient after try-in, and the upper post cavity were filled with light-sensitive composite resin.</p><p><b>RESULTS</b>None of prostheses was loose and no abutment teeth fractured for 6-38 months. All of the fixed restorations were found with good marginal fitness and well masticatory function without sign of gingivitis.</p><p><b>CONCLUSION</b>Insertion-type separate post and post-crown is a better method to restore molar residual root and crown with low occlusogingival distance and large root bifurcation angle.</p>

An experimental study on hepatotoxicity of topiramate in young rats / 中国当代儿科杂志

<p><b>OBJECTIVE</b>Topiramate (TPM) has an evident efficacy in the treatment of childhood epilepsy for multiple pharmacologic properties. However it was reported that it may cause adverse effects such as liver failure and hepatitis, which arouses the attention of the medical field. This study aimed to investigate the hepatotoxicity of low-dosage, high-dosage TPM or TPM along with valproate sodium (VPA) in aspects of biochemistry indexes, oxidative stress indexes and liver pathomorphology in young rats.</p><p><b>METHODS</b>Sixty 3-week-old male Wistar rats were randomly assigned into five groups of 12 rats (Groups A-E). The rats in the experimental groups (Groups A-C) were administered intragastrically with TPM 40 mg/(kg.d), 80 mg/(kg.d) and TPM 40 mg/(kg.d) plus VPA 300 mg/(kg.d) respectively. The rats in the negative control group (Group D) were administered with the same volume of distilled water. The ones in the positive control group (Group E) were treated by injection of 10% carbon tetrachloride dissolved in olive oil subcutaneously at a dose of 5 mL/kg twice a week. After 3-month administration, the changes of body weight and liver pathomorphology were observed; biochemical markers in serum and indexes of oxidative stress in liver homogenate associated with hepatotoxicity were examined.</p><p><b>RESULTS</b>The body weights of rats in the experimental groups were significantly lower than that of rats in the negative control group. The levels of serum alanine aminotransferase, alkaline phosphatase and the content of malondialdehyde, and the activity of superoxide dismutase in liver tissues did not change significantly in the experimental groups. The contents of glutathion in the high dosage of TPM group (29.85 +/- 1.62 mg/g prot) or in the TPM plus VPA group (29.63 +/- 4.47 mg/g prot) were significantly reduced compared with those of the negative control group (33.09 +/- 1.69 mg/g prot) and that of the low dosage of TPM group (32.43 +/- 2.11 mg/g prot) (both P < 0.05). In the histopathological examination, extensive steatosis and diffuse punctate necrosis of hepatocytes distributed in the portal area were found by microscopy in the positive control group. There were granular degeneration of some hepatocytes near the central veins of hepatic lobules in the low dosage of TPM group and punctate necrosis of some hepatocytes in the high dosage of TPM group. In the TPM plus VPA group, histological examination showed granular degeneration and fatty degeneration of partial liver cells and punctate necrosis of some hepatocytes.</p><p><b>CONCLUSIONS</b>Long-term use of TPM can decrease antioxidant capacity of organism, resulting in slight pathological changes of liver tissues. High dosage of TPM or TPM along with VPA administration enhances the risk of the side effects.</p>

Treatment of hemolytic uremic syndrome after acute stage / 中华儿科杂志

<p><b>OBJECTIVE</b>Hemolytic uremic syndrome (HUS) is a common primary disease that can cause acute renal failure in childhood. Renal disease is the most important long-term complication in patients who survived the acute stage of HUS. Use of angiotensin-converting enzyme inhibitors (ACEI) and a restricted protein intake may be beneficial to the patients. However, it is not established whether such patients should be treated with steroids and immunosuppressors. The present study aimed to probe into the benefit of using steroid and immunosuppressor in patients after acute stage of HUS.</p><p><b>METHODS</b>The subjects included 17 patients (aged 9 months to 15 years, 12 males, 5 females) with HUS. Thirteen patients recovered from the acute stage of HUS, and underwent continuative treatment and follow-up. All the patients were treated with ACEI and early restriction of protein intake. Additionally, 2 children manifested as glomerulonephritis, one was treated with triperygium glycosides. Other 11 children who manifested as nephrotic syndrome were treated with prednisone, among them 5 children had no response or had incomplete response to prednisone, for these children short-term high dose cyclophosphamide or methylprednisolone pulse treatment were added; in 3 of the children short-term high dose methylprednisolone treatment was applied additionally for membranoproliferative glomerulonephritis and/or focal segmental glomerulosclerosis and crescentic glomerulonephritis.</p><p><b>RESULTS</b>After follow-up for 2 months to 8 years, 4 patients with milder disease recovered, their blood pressure, renal function and urinalysis became normal, but 1 patient had recurrence. Among 9 patients with severe disease, 6 maintained normal blood pressure, recovered renal function and urinalysis, the other 3 patients failed to comply with treatment protocol and died during the 3rd, 9th and 13th month. The remainder (4 cases) gave up therapy and died on the 27th to 48th days of the course.</p><p><b>CONCLUSION</b>The treatment applied in this study could improve the prognosis of patients after acute phase of HUS evidently by using the steroid and immuno suppressor according to clinical classification and pathological findings. It is recommended that triperygium glycosides is beneficial to children with glomerulonephritis, proteinuria and hematuria after acute stage of HUS. Adjustment of therapeutic schedule based on pathological findings after renal biopsy is helpful. To the patients with progressive renal failure who have no response to the steroid and immunosuppressors, steroid and immunosuppressor should be discontinued and dialysis treatment should be applied. Protocol compliance is also an important factor.</p>

Effects of post length on horizontal load of post-core system / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To access the effects of post length on horizontal load of cast post and core crown.</p><p><b>METHODS</b>120 simulated roots made of polymethylmethacrylate were divided into 15 groups according to different mechanical fulcrum and length of post, made the wax pattern of post-core, casted and cemented the post-core. After saline soak, loaded these specimens on the Instron-4302 by the speed of 1 mm/min and recorded the maximum force of load.</p><p><b>RESULTS</b>The means of fracture resistance Wp11 of 7.0 mm, 7.5 mm, 8.0 mm, 8.5 mm, 9.0 mm were (94.24 +/- 12.47) N, (129.76 +/- 19.89) N, (195.98 +/- 1 2.46) N, (208.88 +/- 24.37) N, (225.67 +/- 53.07) N and the means of dangerous stress (sigma degrees 11 were 65.12 N, 93.07 N, 145.84 N, 161.58 N, 181.49 N; the means of fair stress [sigma11] were 39.41 MPa, 56.34 MPa, 88.34 MPa, 97.86 MPa, 109.94 MPa. It showed that the horizontal load of post-core crown system increased gradually with the increasing of the post length. It appeared the linear regression between the length of the post and fracture resistance and physiologic load.</p><p><b>CONCLUSION</b>The increasing of the post length can increase the horizontal load of post-core crown system. During the pulp preparation of post-core system, the post length should be added as much as possible.</p>

Biomechanical study of restorations of medial-occlusal cavities of endodontically treated premolars / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To compare the different restorations of endodontically treated premolars, and to choose the best method.</p><p><b>METHODS</b>10 pairs of symmetry maxillary first premolars were collected from 10 patients, and randomly divided into 2 groups. Every pair received different treatment accordingly. The test group was set up the medial-occlusal cavities model under the same standard. The 10 pairs teeth were test by instron 4302 universal test machine in speed of 1.00 mm/min until broken up and the top load was recorded. The load angle was 45 degree to the long axis of the teeth, as the load was pointed to the middle of the lingual surface on the buccal cusp. The records were analyzed by paired samples t test.</p><p><b>RESULTS</b>Based on the medial-occlusal cavities, the fracture strength of the full crowned teeth was lower than the full natural teeth, and the fracture strength of the post-crowned teeth was higher than the full natural teeth.</p><p><b>CONCLUSION</b>From the point of biomechanics, the different trauma of the endodontically treated teeth fits to different restorations. The medial-occlusion cavities fit the post-crown restoration mostly.</p>