[Arthroscopic treatment through Tang's approach in the treatment of posterior talus impingement syndrome].

Objective: To analyze the efficacy of arthroscopic posterior ankle debridement through Tang's approach for the treatment of impingement of posterior tubercle of the talus. Methods: A retrospective analysis was performed on 64 patients (35 males and 29 females) with posterior tubercle impingement of the talus who underwent surgical treatment from September 2011 to May 2019 in First Affiliated Hospital of Military Medical University of the Army. The disease occurred in left foot in 31 cases and in right foot in 33 cases, with an age ranged from 15 to 65 years ((36±7) years). All patients underwent arthroscopic debridement of the posterior tubercle of the talus through Tang's approach, in which the patients were placed in the lateral decubitus position, and the arthroscopic access was constructed via the lateral malleolus apex approach and the posterolateral Achilles tendon approach. All patients were assessed preoperatively and postoperatively with the American Association of Ankle Surgeries (AOFAS) ankle-hindfoot score and visual analogue scale (VAS) for pain, as well as imaging, and the data were compared before and after the operation. Results: All patients were followed-up effectively for (15.6±4.2) months. The preoperative AOFAS ankle-hind foot function score was (84±11) points, and it was (92±9) points at the last follow-up (P<0.05); the VAS score for preoperative pain was (4.5±3.0) points and it was (1.0±0.3) points at the last follow-up (P<0.05). The distance from the preoperative posterior tubercle of the talus to the perpendicular to the tangent line in the imaging evaluation was (4.0±2.0) mm, the vertical distance between the posterior edge of calcaneal joint surface and tangent line was (-8.4±4.2) mm, and the average vertical distance between posterior tubercle of talus and tangent line was (-7.9±4.6) mm after operation, the exposed distance from the lower joint was (-2.1±3.0) mm after operation. Conclusions: Arthroscopic debridement of the posterior tubercle of talus through Tang's approach can effectively alleviate the symptoms caused by the posterior tubercle of talus. Tang's approach has the advantages of avoiding repeated position change and disinfection, and reducing the possibility of infection.

[Early clinical efficacy analysis of personalized three-dimensional printing talus prosthesis in the treatment of collapse talus necrosis].

Object To examine the preliminary clinical efficacy of custom-made three-dimensional(3D) printed talus prosthesis in the treatment of collapse talus necrosis. Methods: The clinical data of 8 patients who received 3D printed custom-made talus prostheses replacement for severe collapsed necrosis of the talus at the Orthopaedic Sports Medical Center, the First Affiliated Hospital to Army Medical University were analyzed retrospectively.All patients were male,with an average age of 38.0 years (range:22 to 65 years).There were 5 cases of left talus collapse and 3 cases of right talus collapse,with the course of disease of 29.7 weeks (range:6 to 96 weeks).The CT data of contralateral healthy talus were used for mirror image design references for the prosthesis,and the electron-beam 3D printing technology was used to prepare the prosthesis.Titanium alloy (Ti6Al4V) was taken as the material for the preparation of the talus body prosthesis,and Co-Cr-Mo material was used as the material for the preparation of the tibialis talus lateral joint surface prosthesis,and the subtalar joint surface of the prosthesis was made from a microporous casting technique.The prosthesis was analyzed preoperatively by digital three-dimensional finite element analysis and solid comparison techniques to measure anatomic match of the prosthesis.A longitudinal incision on medial ankle was made.The necrotic talus was completely removed and the prosthesis was then implanted.The patient was reexamined in the outpatient department 3, 6, and 12 months after surgery.Primary outcome measures were the American Orthopaedic Foot and Ankle Society(AOFAS) ankle-hind foot score,visual analogue scale(VAS) and ankle range of motion.Changes in imaging data and plantar pressure were also assessed.Repeated measures analysis of variance and paired-t test were used to compare the data. Results: The talus prosthesis measure preoperatively was completely consistent with that contralateral healthy talus and there was no operation-related complication. All the wounds healed primarily. The patients were followed up effectively for 23.17 months (range:12 to 48 months).The preoperative dorsiflexion of patients was (7.6±5.7)°,it increased to(14.2±6.6)° at 12 month after surgery (t=-2.67,P=0.03).The plantar flexion increased from (22.0±9.9)°preoperatively to (29.2±8.7)° at 12 month after surgery (t=-8.95,P<0.01).Preoperative AOFAS ankle-hind foot score was 26.3±6.6,and it increased to 70.1±2.2,76.0±3.4 and 79.3±4.2 at 3 month,6 month and 12 month after surgery(F=56.81,P<0.01);Pre-operative VAS was[M(QR)]3.0(0.8),and it increased to 2.5(1.0),1.5(1.0),1.0(1.0)at 3 month,6 month and 12 month after surgery(F=20.00,P<0.01).At the last follow-up,imaging reexamination showed that the prosthesis of all patients were in stable position with no sign of subsidence.No secondary ankle fusion or revision was required.The talus height increased from (27.6±6.0)mm preoperatively to (34.6±3.5)mm (t=-2.94,P<0.01).The plantar pressure showed that the maximum pressure on the healthy ankle was(629.9±26.1)N,and that on the affected side was(521.4±14.4)N.The pressure on the healthy ankle was(350.6±29.6)N,and that on the necrotic side was (212.3±9.7)N.The load on the contralateral forefoot was(38.1±2.8)% and that on the necrotic side was(11.5±2.0)%.The load on the contralateral hindfoot was (24.6±2.5)% and that on the necrotic side was (21.1±1.8)%. Conclusions: The custom-made 3D printed talus prosthesis could restore the talus anatomy,recover the ankle joint function,relieve the pain of patients and improve the life quality of patients.The effect on plantar pressure is mainly achieved by adjusting the center of gravity of plantar pressure backwards and the increase of weight bearing of the healthy foot.

Augmented finite-element method for arbitrary cracking and crack interaction in solids under thermo-mechanical loadings.

In this paper, a thermal-mechanical augmented finite-element method (TM-AFEM) has been proposed, implemented and validated for steady-state and transient, coupled thermal-mechanical analyses of complex materials with explicit consideration of arbitrary evolving cracks. The method permits the derivation of explicit, fully condensed thermal-mechanical equilibrium equations which are of mathematical exactness in the piece-wise linear sense. The method has been implemented with a 4-node quadrilateral two-dimensional (2D) element and a 4-node tetrahedron three-dimensional (3D) element. It has been demonstrated, through several numerical examples that the new TM-AFEM can provide significantly improved numerical accuracy and efficiency when dealing with crack propagation problems in 2D and 3D solids under coupled thermal-mechanical loading conditions. This article is part of the themed issue 'Multiscale modelling of the structural integrity of composite materials'.

Role of inflammatory responses in the pathogenesis of human cerebral aneurysm.

We aimed to detect expressional profiles of intracellular cell adhesion molecule-1 (ICAM-1), nuclear factor-kappa B (NF-κB), and monocyte chemoattractant protein-1 (MCP-1) in human cerebral aneurysm, in order to investigate the effect of chronic inflammation on the pathogenesis of cerebral aneurysm. Samples from 40 cases of human cerebral aneurysms diagnosed at our hospital were selected along with 20 normal cerebral artery samples. Western blotting and immunohistochemical (IHC) staining were used to reveal expressional profiles of ICAM-1 and NF-κB in the aneurysmal wall of patients and normal cerebral artery tissues. Reverse transcription (RT)-PCR was employed to detect changes in transcript levels of MCP-1 mRNA. Western blotting showed significantly higher expressions of ICAM-1 and NF-κB in patients with cerebral aneurysm compared to the normal group (P < 0.01), which was consistent with IHC staining results. RT-PCR revealed significantly higher MCP-1 transcripts in cerebral aneurysm tissues compared to the normal group (P < 0.01), in addition to a positive relationship between ICAM-1 and NF-κB expression levels. In conclusion, expression levels of ICAM-1, NF-κB, and MCP-1 in patients are significantly elevated, suggesting an enhanced chronic inflammatory response and a significant correlation between inflammatory factors/adhesion molecules and the pathogenesis of cerebral aneurysm.

The influence of different movements on ambulatory blood pressure in hypertensive subacute stroke patients.

OBJECTIVE: This study evaluated variation in blood pressure (BP) in hypertensive subacute stroke patients performing eight different types of active movement, and variations in BP over time. METHODS: The study included 35 subacute stroke patients (60 - 74 years old) and 15 age-matched healthy volunteers. Ambulatory systolic and diastolic BP was measured over 4 consecutive days, before and during active movement. RESULTS: The greatest effect of the different active movements in stroke patients was on mean systolic BP variability (BPV). There was a significant difference in systolic and diastolic BPV between stroke patients at different time-points and compared with healthy volunteers. Systolic BPV during shifting from the ward to the rehabilitation centre was significantly higher than for all other active movements. Mean systolic BPVs during the sessions on the first and second days were significantly higher than for the sessions on the third and fourth days in stroke patients and compared with healthy volunteers. CONCLUSIONS: Systolic BP was found to be increased in hypertensive subacute stroke patients during their first and/or second attempts at performing active movements. Therapists should consider the BP of hypertensive subacute stroke patients during these first two attempts, especially for activities involving the patient moving from the ward to the rehabilitation centre.

Association of lipopolysaccharide-binding protein gene polymorphisms with cerebral infarction in a Chinese population.

Toll-like receptors (TLRs) have been widely known for their role as an important mediator of immune reactions in the development and progression of atherosclerotic (AS) lesions, which play the most important role in the occurrence of cerebral infarction (CI). The lipopolysaccharide (LPS)-lipopolysaccharide binding protein (LBP) compounds connect LPS receptor-CD14 and play an important role in promoting inflammatory reaction through TLRs. This study was designed to study whether LBP genetic polymorphisms are associated with CI risk in a Chinese population. LBP c.291T>C and c.1306T>C single nucleotide polymorphisms (SNPs) were genotyped in 366 CI cases and 200 controls from Changsha by using method of Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). Blood lipid and lipoprotein levels were also detected and the intima-media thickness (IMT) of carotid arteries were determined. No significant difference in genotype and allele distribution of the LBP c.291T>C and LBP c.1306T>C polymorphism was observed between the cases and controls (P > 0.05). CI patients carrying the TC genotype for both LBP c.291T>C and c.1306T>C polymorphisms showed higher carotid IMT than those carrying the TT genotype (P < 0.05, respectively). LBP c.291T>C and c.1306T>C polymorphisms were significantly associated with carotid IMT in Changsha, China, but both polymorphisms were not associated with risk of atherosclerotic CI.

Changes in hippocampal synapses and learning-memory abilities in a streptozotocin-treated rat model and intervention by using fasudil hydrochloride.

Fasudil hydrochloride (FH), a Rho kinase inhibitor, is used to treat neurological diseases. This study aims to elucidate the anti-dementia role of FH in Alzheimer's disease. Twenty-four Sprague-Dawley rats were randomly divided into four groups: (1) sham-operated group (control), (2) sham-operated followed by FH administration group (sham+FH), (3) streptozotocin (STZ)-treated group (STZ), and (4) STZ treatment followed by FH administration group (STZ+FH). Rats in the STZ and STZ+FH groups received two divided doses of STZ (1.5 mg/kg) intracerebroventricularly on days 1 and 3, whereas control and sham+FH group rats were given citric acid/sodium citrate buffer. Rats in the sham+FH and STZ+FH groups were then treated intraperitoneally with FH (10 mg/kg) for 4 weeks, and rats in the STZ and control groups were treated with saline. Learning and memory were measured using the Morris water maze test. The synaptic ultrastructure in the CA1 region of the hippocampus was observed using electronic microscopy. The expression of synaptophysin (SYP) was measured using real-time polymerase chain reaction and western blot analyses; the expression of p-LIMK2 and p-cofilin were also detected using western blot analysis. The results indicate that STZ induced deficit in learning/memory, decrease in SYP expression, degeneration in synaptic structures, and increase in the expressions of p-LIMK2 and p-cofilin. These changes were reversed by the administration of FH, suggesting that FH has anti-dementia properties that protect synaptic structure and function. FH induced dephosphorylation (inactivation) of LIMK2 and subsequent dephosphorylation (activation) of cofilin, which may be responsible for the amelioration of neuronal synaptic structure and function.

No association of C-1019G promoter polymorphism of 5-HT1A receptor gene with migraine.

It is well known that migraine has a strong genetic component, although the type and number of genes involved remains unclear. There is evidence to suggest that serotonin-related genes may be involved in the pathogenesis of migraine. To investigate whether the 5-HT1A receptor gene contributes to the risk of migraine we performed an association study of C-1019G promoter polymorphism of the gene in 102 migraineurs and 93 controls. Subjects were of Han Chinese origin. No significant differences in allele (P=0.82) or genotype frequencies (P=0.71) were seen in migraineurs compared with the controls. When migraine with aura, without aura, with family history, without family history were analyzed separately, the frequencies did not vary significantly. Our results suggest that C-1019G in 5-HT1A is not a major genetic risk factor for migraine.

Re-evaluating the toughness of human cortical bone.

Data for fracture in human humeral cortical bone are re-analyzed to assess the validity for this material of linear-elastic fracture mechanics (LEFM), which is the standard method of analyzing toughness and one basis for analyzing clinical data relating to bone quality. A nonlinear fracture model, which is based on representing the damage zone in the bone by a cohesive model, is calibrated against a number of sets of test data for normal (not diseased or aged) human cortical bone taken from cadavers. The data consist of load vs. load-point displacement measurements from standard compact-tension fracture tests. Conventional LEFM is unable to account for the shape of the load-displacement curves, but the nonlinear model overcomes this deficiency. Calibration of the nonlinear model against one data curve leads to predictions of the peak load and the displacement to peak load for two other data curves that are, for this limited test set, more accurate than those made using LEFM. Furthermore, prior observations of damage mechanisms in bone are incompatible with the modeling assumption of LEFM that all nonlinearity is confined to a zone much smaller than the specimen and the crack length. The predictions of the cohesive model and the prior observations concur that the length of the nonlinear zone in human cortical bone varies in the range 3-10 mm, which is comparable to or larger than naturally-occurring bones and the specimens used to test them. We infer that LEFM is not an accurate model for cortical bone. The fracture toughness of bone deduced via LEFM from test data will not generally be a material constant, but will take different values for different crack lengths and test configurations. The accuracy of using LEFM or single-parameter fracture toughness for analyzing the significance of data from clinical studies is called into question. The nonlinear cohesive zone model is proposed to be a more accurate model of bone and the traction-displacement or cohesive law is hypothesized to be a material property. The cohesive law contains a more complete representation of the mechanics of material failure than the single-parameter fracture toughness and may therefore provide a superior measure of bone quality, e.g., for assessing the efficacy of therapy for osteoporosis.

Fracture length scales in human cortical bone: the necessity of nonlinear fracture models.

Recently published data for fracture in human humeral cortical bone are analyzed using cohesive-zone models to deal with the nonlinear processes of material failure. Such models represent the nonlinear deformation processes involved in fracture by cohesive tractions exerted by the failing material along a fracture process zone, rather than attributing all damage to a process occurring at a single point, as in conventional linear-elastic fracture mechanics (LEFM). The relationship between the tractions and the net displacement discontinuity across the process zone is hypothesized to be a material property for bone. To test this hypothesis, the cohesive law was evaluated by analyzing published load vs. load-point displacement data from one laboratory; the calibrated law was then used to predict similar data taken for a different source of bone using a different specimen geometry in a different laboratory. Further model calculations are presented to illustrate more general characteristics of the nonlinear fracture of bone and to demonstrate in particular that LEFM is not internally consistent for all cases of interest. For example, the fracture toughness of bone deduced via LEFM from test data is not necessarily a material constant, but will take different values for different crack lengths and test configurations. LEFM is valid when the crack is much longer than a certain length scale, representative of the length of the process zone in the cohesive model, which for human cortical bone ranges from 3 to 10mm. Since naturally occurring bones and the specimens used to test them are not much larger than this dimension for most relevant orientations, it is apparent that only nonlinear fracture models can give an internally consistent account of their fracture. The cohesive law is thus a more complete representation of the mechanics of material failure than the single-parameter fracture toughness and may therefore provide a superior measure of bone quality. The analysis of fracture data also requires proper representation of the approximately orthotropic elasticity of the bone specimen; if the specimen is incorrectly assumed to be isotropic, the initial measured compliance cannot be reproduced to within a factor of four and the fracture toughness deduced from the measured work of fracture will be overestimated by approximately 30%.

[Kindling model of SD rats induced by injection of PTX intraperitoneally].

OBJECTIVE: To observe the kindling model of Sprague-Dawley (SD) rats induced by injection of different doses of picrotoxin (PTX) intraperitoneally, and to evaluate the effect of the drug on the model. METHODS: SD rats were devided randomly into four groups: control group, epilepsy Group I (PTX, 1.5 mg.kg-1.d-1), epilepsy Group II (PTX, 2 mg.kg-1.d-1) and the phenobarbital group. The kindling model of rats was induced by daily injection of PTX intraperitoneally. The seizures in the rats were observed, and the results of electroencephalography (EEG) were recorded. RESULTS: On the 20th day after injection of PTX, 71% SD rats were kindled in epilepsy Group I; 4 rats were dead, 2 rats were at stage IV of convulsions, and 2 rats were at stage V of convulsions in epilepsy Group II; 17% rats were kindled in the phenobarbital group. The EEG demonstrated spike discharges in the kindled rats. CONCLUSIONS: In this models, the better dose of PTX is 1.5 mg.kg-1.d-1, and phenobarbital sodium can protect SD rats injected PTX intraperitoneally from seizure.

[Study on p53 gene expression following transient ischemia in the gerbil].

OBJECTIVE: To study the expression of p53 gene after transient ischemia in the gerbil. METHODS: Northern blot was used to detect the expression of the p53 mRNA in the forebrain during different periods after post-ischemic reperfusion in the gerbil. RESULTS: The expression of p53 mRNA increased in the forebrain during the 6th hour to the 3rd day of reperfusion following 6 min of ischemia (P < 0.05). CONCLUSION: The high level expression of p53 might induce neuronal apoptosis after ischemia.

[Heat shock protein 70 expression following transient ischemia in the gerbil].

OBJECTIVE: To study the expression of heat shock protein 70(HSP70) following transient ischemia in the gerbil. METHODS: Immunohistochemistry(IHC) was used to determine the expression of the HSP70 protein in the forebrain during different periods after post-ischemic reperfusion in the gerbil, and the neuronal damage was examined with microscope. RESULTS: The HSP70 protein was only expressed at the 1st day of reperfusion(P < 0.01); and most of the neurons showed damage on the 7th day of reperfusion; heat-preconditioning could increase the expression of HSP70 protein(P < 0.01) and decrease the neuronal damage(P < 0.001) after 6 min of ischemia. CONCLUSION: Heat-preconditioning could protect neural cells from damage by increasing the expression of the HSP70 protein.

[Relationship between insulin resistance and clustering of risk factors of cerebrovascular disease].

OBJECTIVE: To study the relationship between insulin resistance and clustering of risk factors of cerebrovascular disease. METHODS: The serum concentrations of fasting glucose, insulin, lipids, the activities of tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor-1(PAI-1), and the level of blood pressure were measured in 159 patients with stroke and 40 healthy control subjects. RESULTS: All subjects were divided into 4 groups in the light of number of risk factors of cerebrovascular disease. As the number of risk factors increased, the insulin sensitivity index (ISI) in four groups gradually decreased. The ISI in the patients with cerebrovascular disease was negatively associated with increased levels of SBP, DBP, TG, APOB, and PAI-1 activity (P < 0.01) and positively with decreased level of HDL (P < 0.01). CONCLUSION: Insulin resistance is associated with clustering of risk factors of cerebrovascular disease, the more resistant, the more clustered.

[The model and results of intervention trial of stroke risk factors in Changsha].

To develop an effective method for minimizing the incidence and mortality of cerebrovascular disease, we studied the sample population of intervention community (8,052 subjects) and control community (8,065 subjects) in Changsha. 2,631 subjects in the intervention community and 2,733 subjects in the control community with age more than 35 years were enrolled for a cohort study from January 1, 1986 to December 31, 1990. The annual incidence of stroke was 315/10(5) in the control community and 220/10(5) in the intervention community. The annual incidence of stroke was significantly lower in the intervention community than in the control community (P < 0.01). The incidence of stroke in 1990 dropped by 66.4% compared to that in 1986 in the intervention community. But, in the control community it dropped by 9.7%. The change of the mortality and incidence of stroke in the two communities was similar.

Retinal changes in a mutant form of goldfish with megalophthalmia.

The retinal changes of a mutant strain of goldfish with megalophthalmia were studied by histology, electron microscopy and biochemistry. Changes in the morphology of the pigment epithelium, decrease in number of photoreceptors, thinning out of retinal layers and the existence of spaces in the retina were all features as the eyes grew in size. Invasion of macrophages was also evident in the retina. A decrease in leucine uptake per milligram of retina was also detected as the eye grew beyond 0.8 millilitre in volume. These changes, although related to volume changes (i.e., growth) of the eyes, were found to have little relationship with increase of intraocular pressure as intraocular pressures in the growing eyes of the mutant strain did not change much. Goldfish from a control strain with similar eye volumes and sizes (ages) were used for comparison and similar changes as in the mutant were not apparent.

Bilateral retinal responses after lens disruption in rabbits with and without skin graft.

In the rabbit, lens disruption produced very little histological changes in the retina. However, lens disruption after skin graft produced an alarming picture with infiltration of inflammatory cells and degeneration of retinal layers.