Suppression of matrix metalloproteinase-2 via RNA interference inhibits pancreatic carcinoma cell invasiveness and adhesion

AIM:To investigate the inhibitory effects of RNA interference (RNAi) on expression of matrix metalloproteinase-2 (MMP-2) gene and invasiveness and adhesion of human pancreatic cancer cell line,BxPC-3.METHODS:RNAi was performed using the vector (pGPU6)-based small interference RNA (siRNA) plasmid gene silence system to specifically knock down MMP-2 expression in pancreatic cancer cell line,BxPC-3. Four groups of different specific target sequence in coding region of MMP-2 and one non-specific sequence were chosen to construct four experimental siRNA plasmids of pGPU6-1,pGPU6-2,pGPU6-3 and pGPU6-4,and one negative control siRNA plasmid of pGPU6 (-). MMP-2 expression was measured by reverse transcription polymerase chain reaction (RT-PCR) and Western blot. Cell proliferation and apoptosis were examined by methyl thiazolyl tetrazolium (MTT) and flow cytometry,respectively. The abilities of adhesion and invasion were detected by cell adhesion assay and cell invasion assay using Transwell chambers.RESULTS:The expression of MMP-2 was inhibited and the inhibitory effects of different sequence varied. pGPU6-1 group had the most efficient inhibitory effect,followed by pGPU6-2 and pGPU6-3 groups.Invasiveness and adhesion were more significantly reduced in pGPU6-1,pGPU6-2 and pGPU6-3 groups as compared with pGPU6 (-) and blank control groups. However,no difference concerning cell proliferation and apoptosis was observed after transfection between experiment groups and control groups.CONCLUSION:RNAi against MMP-2 successfully inhibited the mRNA and protein expression of MMP-2 in the pancreatic cancer cell line,BxPC-3,leading to a potent suppression of tumor cell adhesion and invasion without affecting cell proliferation and apoptosis. These findings suggest that the RNAi approach towards MMP-2 may be an effective therapeutic strategy for the clinical management of pancreatic tumor.

PRESERVATION OF THE HYPOTHALAMIC STRUCTURES IN THE TOTAL RESECTION OF CRANIOPHARYNGIOMA

Objective. To explore an effective method of surgical management of craniopharyngioma. Subjects and methods. Fifty patients with craniopharyngioma had total andsubtotal tumor ectomy. There were 29 males and 21 females, ranging in age from 15 to 56 years (mean 34.1 years). MR imaging showed that the tumors were locatedin the superior sellar region in 24 cases, in superior sella region and extended into the third ventricular floor in 19 cases, into parasella in 3 cases and down to intrasella in 4 cases. Complete cystic tumors were found in 5 cases, whilethe partial cystic tumor in 24 cases and complete solid tumors in 21 cases. Pterional approach was used in 48 patients and subfrontal approach in 2 patients. Great attention was paid to the preservation of the perforating arteries from thecarotid, posterior and anterior communicating and anterior choroidal arteries to the hypothalamic structures. The clinical outcome was evaluated according to the GOS scale.Results. Of the 50 patients surgically treated, 47 patients obtained total ectomy of the tumor and 3 patients with the secondary surgery had subtotal ectomy of the tumor. The pituitary stalk was preserved in 29(58%) patients, severed in 14 patients and unidentified in 7 patients. Forty-six patients regained a normal life; one patient needed assist in life. Of the 3 deaths, one patient died of diabetes insipidus, one of inhalation asphyxia, and another one of water and sodium disorders. Conclusion. Avoidance of the injury to the neural structures in the thirdventricular floor and preservation of the perforating arteries to hypothalamus are the key to achieve good surgical results in treating craniopharyngioma.

The Clinical Anatomy of the Cavernous Sinus

Introduction: The cavernous sinus (CS) is a very important concept because it is not only interesting to anatomical theory but also useful to clinical medicine, especially in the field of surgery. This paper described the microsurgical anatomy of the CS with special attention to its concept that the CS was really venous sinus or plexus. Materials and Methods: Fifty CSs from 25 Chinese adult cadaver heads fixed in 10% methanal, whose artery and vein were injected with red and blue latex, respectively, dissected stepwise under the operating microscope. Results: Asymmetric and nonintegral blue latex distributed in the cavity of the CS to form a retina with various diameters and repeatedly diverged and converged were observed under the surgical microscope with magnification 5 - 25, after the lateral wall of the CS was opened by maxillary approach. Measurement of sinus included length, diameter and triangular structure of the CS. It is very important to understand the microsurgical anatomy of the CS for neurosurgeons. Conclusion: The CS was venous plexus rather than sinus. The lateral wall of the sinus had two layers, and the lateral cavity of the sinus really did exist even though it was very small. The triangles where maxillary approach passed were more important for neurosurgeons.

Distribution of wall shear stress in carotid plaques using magnetic resonance imaging and computational fluid dynamics analysis： a preliminary study

Background Wall shear stress is an important factor in the destabilization of atherosclerotic plaques. The purpose of this study was to assess the distribution of wall shear stress in advanced carotid plaques using high resolution magnetic resonance imaging and computational fluid dynamics.Methods Eight diseased internal carotid arteries in seven patients were evaluated. High resolution magnetic resonance imaging was used to visualize the plaque structures, and the mechanic stress in the plaque was obtained by combining vascular imaging post-processing with computational fluid dynamics.Results Wall shear stresses in the plaques in all cases were higher than those in control group. Maximal shear stresses in the plaques were observed at the top of plaque hills, as well as the shoulders of the plaques. Among them,the maximal shear stress in the ruptured plaque was observed in the rupture location in three cases and at the shoulder of fibrous cap in two cases. The maximal shear stress was also seen at the region of calcification, in thrombus region and in the thickest region of plaque in the other three cases, respectively.Conclusion Determination of maximal shear stress at the plaque may be useful for predicting the rupture location of the plaque and may play an important role in assessing plaque vulnerability.

Concurrent intracranial and extracranial artery stenosis and the prognosis of transient ischaemic symptoms or imaging-negative ischaemic stroke

Background and purpose Transient ischaemic attack(TIA),transient symptoms with infarction(TSI)and diffusion-weighted imaging(DWI)-negative acute ischaemic stroke(AIS)share similar aetiologies but are considered to have a rather benign prognosis.We intended to investigate the association between intracranial atherosclerotic stenosis(ICAS),extracranial atherosclerotic stenosis(ECAS)and the prognosis of patients with TIA,TSI and DWI-negative AIS.Methods Clinical and imaging data of eligible participants were derived from the Chinese Intracranial Atherosclerosis study,according to symptom duration,acute infarction on DWI and discharge diagnosis.Based on the severity and location of arterial atherosclerosis,we categorised the study population into four groups:no or<50% ICAS and no ECAS;≥50% ICAS but no ECAS;no or<50%ICAS with ECAS;and concurrent≥50% ICAS and ECAS.Using multivariable Cox regression models,we analysed the relationship between the severity and distribution of large artery atherosclerosis and the prognosis of TIA,TSI and DWI-negative AIS.Results A total of 806 patients were included,67.3% of whom were male.The median age of the study participants was 63 years.Patients in the concurrent≥50% ICAS and ECAS subgroup had both a significantly higher 1-year recurrence rate(adjusted HR 3.4(95%CI 1.15 to 10.04),p=0.027)and a higher risk of composite vascular events(adjusted HR 3.82(95%CI 1.50 to 9.72),p=0.005).Conclusions Concurrent ICAS and ECAS is associated with a higher possibility of 1-year recurrent stroke or composite vascular events.Large artery evaluation is necessary to assess patients with transient ischaemic symptoms or DWI-negative AIS.Progress in shortening the time interval between symptom onset and large vessel evaluation is needed.

Semaphorin 3A-hypoxia inducible factor 1 subunit alpha co-overexpression enhances the osteogenic differentiation of induced pluripotent stem cells-derived mesenchymal stem cells in vitro

Background:Mesenchymal stem or stromal cells(MSCs)derived from the induced pluripotent stem cells(iPSCs)have uniform biological activity,which makes the clinical application of MSCs in bone repair possible.Culturing the iPSC-MSCs onto osteoconductive materials is a promising tissue engineering-based strategy in bone regeneration.The aim of this work was to evaluate the effects of semaphorin 3A(Sema3A)and hypoxia inducible factor 1 subunit alpha(HIF1α)co-overexpression on the survival and osteogenic differentiation of iPSC-MSCs.Methods:Sema3A and HIF1αwere linked together with the three(GGGGS;G,glycine;S,serine)peptide fragment,and their co-expression in iPSC-MSCs was mediated by a lentiviral vector.The fusion protein retained the immune reactivity for both Sema3A and HIF1αas determined with Western blotting.iPSC-MSCs were infected with overexpression lentivirus(oeLenti)as negative control,oeLenti-Sema3A,oeLenti-HIF1αor oeLenti-Sema3A-HIF1αlentiviruses.Results:Sema3A overexpression alone promoted the osteogenic differentiation of iPSC-MSCs(the activity and/or expression of osteoblast markers,such as alkaline phosphatase,osteopontin,and osteocalcin,were upregulated),and suppressed cell survival.The Sema3A-HIF1αfusion protein showed a comparable osteoconductive effect to that of Sema3A without reducing cell survival.We further seeded iPSC-MSCs modified by SemaA-HIF1αoverexpression onto hydroxyapatite(HA)scaffolds,and evaluated their growth and differentiation on this three-dimensional material.Additional data indicated that,as compared to iPSC-MSCs cultured in ordinary two-dimensional dishes,cells cultured in HA scaffolds grew(blank vs.HA scaffolds:0.83 vs.1.39 for survival)and differentiated better(blank vs.HA scaffolds:11.29 vs.16.62 for alkaline phosphatase activity).Conclusion:Modifying iPSC-MSCs with pro-osteogenic(Sema3A)and pro-survival(HIF1α)factors may represent a promising strategy to optimize tissue engineering-based strategy in bone repair.

Establishment of intramedullary spinal cord glioma model in rats

Background Treating intramedullary spinal cord gliomas is a big challenge because of limited options, high recurrence rate and poor prognosis. An intramedullary glioma model is prerequisite for testing new treatments. This paper describes the establishment of a rodent intramedullary glioma model and presents functional progression, neuroimaging and histopathological characterization of the tumour model. Methods Fischer344 rats （n=24） were randomized into two groups. Group 1 （n=16） received a 5 pl intramedullary implantation of 9L gliosarcomal （105） cells. Group 2 （n=8） received a 5 pl intramedullary injection of Dulbecco＇s modified Eagle medium. The rats were anesthetized, the spinous process of the T10 vertebra and the ligamentum flavum were removed to expose the T10-11 intervertebral space and an intramedullary injection was conducted into the spinal cord. The rats were evaluated preoperatively and daily postoperatively for neurological deficits using the Basso, Beattie and Bresnahan scale. High resolution magnetic resonance images were acquired preoperatively and weekly postoperatively. When score equal to 0, rats were sacrificed for histopathological examination. Results Rats implanted with 9L gliosarcoma cells had a statistically significant median onset of hind limb paraplegia at （16.0±0.4） days, compared with rats in the control group in which neurological deficits were absent. Imaging and pathological cross sections confirmed intramedullary 9L gliosarcoma invading the spinal cord. Rats in the control group showed no significant functional, radiological or histopathological findings of tumour. Conclusions Rats implanted with 9L cells regularly develop paraplegia in a reliable and reproducible manner. The progression of neurological deficits, neuroimaging and histopathological characteristics of intramedullary spinal cord gliomas in rats is comparable with the behaviour of infiltrative intramedullary spinal cord gliomas in patients.

Application of Keyhole Microneurosurgery in China

INTRODUCTIONMicroneurosurgery made its debut in the early 1960s. It became popular in the medical field and became a primary operation method in neurosurgery since it improved the efficacy of neurosurgery with a less surgery-related injury. Over the past five decades, the accumulation of experience of microsurgery, improvement of microsurgery techniques, refined micro-instruments, and advanced preoperative diagnostic imaging allowed the evolution of microneurosurgery techniques and further reduced surgery-related trauma.