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Streptococcus mutans (S. mutans) is generally regarded as a major contributor to dental caries because of its ability to synthesize extracellular polysaccharides (EPS) that aid in the formation of plaque biofilm. The VicRKX system of S. mutans plays an important role in biofilm formation. The aim of this study was to investigate the effects of vicK gene on specific characteristics of EPS in S. mutans biofilm. We constructed single-species biofilms formed by different mutants of vicK gene. Production and distribution of EPS were detected through atomic force microscopy, scanning electron microscopy and confocal laser scanning microscopy. Microcosmic structures of EPS were analyzed by gel permeation chromatography and gas chromatography-mass spectrometry. Cariogenicity of the vicK mutant was assessed in a specific pathogen-free rat model. Transcriptional levels of cariogenicity-associated genes were confirmed by quantitative real-time polymerase chain reaction. The results showed that deletion of vicK gene suppressed biofilm formation as well as EPS production, and EPS were synthesized mostly around the cells. Molecular weight and monosaccharide components underwent evident alterations. Biofilms formed in vivo were sparse and contributed a decreased degree of caries. Moreover, expressional levels of genes related to EPS synthesis were down-regulated, except for gtfB. Our report demonstrates that vicK gene enhances biofilm formation and subsequent caries development. And this may due to its regulations on EPS metabolism, like synthesis or microcosmic features of EPS. This study suggests that vicK gene and EPS can be considered as promising targets to modulate dental caries.
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Animales , Ratas , Biopelículas , Caries Dental , Placa Dental , Streptococcus mutans/genéticaRESUMEN
ObjectiveTo discuss the role of neuronavigaition technique in localizing and facilliating microsurgical resection of intracranial ateriovenous malformations (AVM) .Methods Forty-three cases with intracranial AVM treated microneurosurgically asisting by Stryker Leibinger neuronavigation system were retrospectively analyzed.Results After reaching neuronavigation calculated technical accuracy (less than 2 mm) and continual intraoperative navigating accuracy, all of the 43 AVM lesions were completely resected.In 41 patients, syptoms were significantly improved (95.4％) at discharge, new neurofuntion defection were found in 2 patients(4.6％) , no death occured.ConclusionNeuronavigation techniques helps the surgery in planning a precise surgical approach to the targeted AVM lesion and tracing the neurovascular structures ,improves the safety of the surgery and the functional outcome of the patients, contribute to lesion resection and reduce operative complications.
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Objective To explore the application of utrasonic technology-assited microsurgery resection of ventral or ventrolateral spinal schwannomas.Methods Forty patients with ventral or ventrolateral spinal schwannomas were treated by CUSA-assited microsurgery.Results The tumors were totally resected suc-cessfully acompanied by minimal blood loss and adjacent structures could avoid damaged.Preoperative and postoperative magnetic resonance imaging demonstrated complete resection in all cases.Neurological func-tions had good recovery.With follow-up of 3 months to 3 years,there was no instability of the spine or any recurrence.Conclusion utrasonic technology-assited microsurgery resection of ventral or ventrolateral spi-nal schwannomas by posterior approach appears a safe,efficient mini-invasive surgical approach,without mechanical or heat injury.
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objective To explore the application of navigation-assited microsurgery resection of posterior fossa solid hemangioblastoma.Methods The data of 16 patients with posterior fossa solid hemangioblastoma treated by navigation-assited microsurgery were analyzed retrospectively,compared with 19 patiems treated by microsurgery who suffered the same disease in the similar location(control group).Results The tumors were totally resected successfully acompanied by minimal blood loss and shortening of the operation time,compared with the control group.Manipulation and removal of these tumors were actually easier,in addition,adjacent structures can avoid damage.Conclusions Navigation-assited microsurgery is useful technique to surgical resection of fossa solid hemangioblastoma by significantly reducing blood loss at the time of surgery and operation procedure time,avoiding damage to the adjacent structures,and reducing the surgery complications and mortality.
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Objective To investigate the value of neuronavigation system in resection of pituitary adenoma through the endonasal transsphenoidal approach. Methods Twenty-one patients with pituitary adenomas underwent magnetic resonance imaging (MRI) or CT scans studies. The image datasets were transported into the neuronavigation system. The anatomic information of approach was reconstructed for three-dimensional visualization and the best approach was designed. The midline structure and internal carotid artery were displayed in real-time intraoperatively, the anterior-wall of sphenoidal sinus and the floor of sella were accurately opened and the tumor was resected guiding by neuronavigation system. Results All the operations were smoothly and accurately performed under the neuronavigation by transsphenoidal approach. No injury occurred in the internal carotid artery and cavernous sinus. After surgery, 13 patients got better vision and visual field. Postoperative transient diabetes insipidus was found in 11 cases, and CSF leak in 1 and serious hyponatremia in 2 cases. Total tumor removal was achieved in 17 patients and subtotal removal in 2 cases during operations, which were confirmed by postoperative MRI. Three-month follow-up data showed only one recurrence case (subtotal tumor removal), the recurrence rate was 4.8%. Conclusion Neuronavigation system provided real-time localization with three-dimensional anatomic information of the endonasal transsphenoidal approach during pituitary adenomas surgery. As a result, the approach proceeds more smoothly and accurately, the tumor can be resected more completely, the surgical injury and complications can also be reduced.
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OBJECTIVE:To investigate the molecular mechanism of cerebral vasospasm (CVS) from the perspectives of the basic molecular biology of cerebrovascular regulation, vascular cell proliferation, inflammatory reactions of vascular cells, and gene activation.DATA SOURCE: By using the key words "subarachnoid hemorrhage","cerebral ischemia", "temporal", and "molecular biology", we retrieved the related articles between January 1998 and December 2004 in Medline,and the language was limited to English.STUDY SELECTION: All articles related to our study purpose were setal subjects. Exclusion criteria: Duplicated experiments. The rest of articles were searched for the full text.DATA EXTRACTION: Totally 20 articles related to the molecular mechanism of CVS induced by subarachnoid hemorrhage (SAH) with or without randomized studies were selected, and 14 of them accorded with the inclusion criteria. The other 6 papers of duplicated study were excluded.oxygen radicals damage both cerebral endothelial and smooth muscle cells through the following possible mechanism: increasing endothelial permeability, increasing intracellular calcium and inositol 1,4,5-triphosphate levlarize and show impaired relaxation after SAH. This may be due to a depletion of the energy metabolism causing a dysfunction of ion pumps or inhibition of potassium channels, which leads to membrane depolarization gene activation can relieve CVS.CONCLUSION: The patbogenesis of SAH-induced CVS may be related to a number of pathological processes, including endothelial damage, smooth muscle cell contraction resulting from dysfunction of ion pumps or PKC activation, vascular cell proliferation, inflammatory reaction of the vascular wall, and gene activation.
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Objects To assess the effect of BMP(bone morphogenetic protein) in orthotopit grafting with an autogenous cranial bone flap in cranioplasty.Methods 45 cases (48 locations ) have been reconstructed by orthotopic repair with autogenous bone flap, it has been divided into two group;26 locations of them using porous autogenous bone flap plus BMP (group Ⅰ), 22 locations of them only using porous autogenous bone flap(group Ⅱ), All cases have been closely followed up for 1～2 years with X-ray and CT , including postoperative complications, absorption or regeneration of the bone flap. Results No flexible with the porous autogenous bone flap was seen , and the appearance was perfectly. The bone graft survival and besetting apposition were all right. The gap disappears gradually. It is obvious that the osteotylus come into being. The density of bone flap was normal in group Ⅰ. 5 cases in group Ⅱ have shown that bone partial absorption occurred and the density reducing in the center of the flaps,and with the significant difference. Conclusions The local application of BMP can avoid bone flap absorption and stimulate osteotylus morphofogenesis.