Safety and efficacy of a novel plastic stent coated with stone-dissolving agents for the treatment of biliary stones in a porcine model.

BACKGROUND AND STUDY AIM: We previously reported on a plastic stent that was coated with ethylenediaminetetraacetic acid (EDTA) and sodium cholate, which dissolved common bile duct (CBD) stones ex vivo. The aim of this study was to investigate the safety and efficacy of such stents on biliary stones in a live porcine model. METHODS: Stents without coating or with degradable membranes containing 0 % or 50 % EDTA and sodium cholate were inserted together with human CBD stones into the porcine CBD. Serum laboratory variables, histological examinations of the bile duct, and the weight change in stones were compared during and after stent placement for 6 months. RESULTS: A total of 16 pigs were included (5 no coating, 5 0 % coating, 6 50 % coating). Biliary stones showed decreased weight in all groups; however, stones in the group with 50 % coated stents showed a greater reduction in weight compared with the no coating and the 0 % coating groups (269 ±â€Š66 mg vs. 179 ±â€Š51 mg [P = 0.09]; 269 ±â€Š66 mg vs. 156 ±â€Š26 mg [P = 0.01], respectively). CONCLUSIONS: The plastic stent coated with 50 % agent enhanced CBD stone dissolution in vivo and may be a promising tool for patients with difficult biliary stones.

The effect of a novel drug-eluting plastic stent on biliary stone dissolution in an ex vivo bile perfusion model.

BACKGROUND: Temporary plastic stent insertion has been considered a safe and effective bridge therapy for difficult common bile duct (CBD) stones. Infusing chemicals to directly dissolve stones through the bile duct might also be effective. However, there are no studies on the efficacy of the combination of these 2 approaches. OBJECTIVE: To investigate the efficacy of a novel ethylenediaminetetraacetic acid (EDTA) and sodium cholate-eluting plastic stent on biliary stones. DESIGN: Ex vivo model by using different doses of active ingredient. SETTING AND INTERVENTIONS: An ex vivo bile duct model perfused with porcine bile was created. Stents coated with degradable membranes containing various concentrations of EDTA and sodium cholate were placed in the model with CBD stones. MAIN OUTCOME MEASUREMENTS: The change in the weight of stents and stones was measured every week during perfusion until the coated membranes were completely biodegraded. RESULTS: The time that the stents required to be fully degraded and the efficiency of stone dissolution were positively correlated with the percentage of EDTA and sodium cholate in the stent membrane. However, the 50% EDTA and sodium cholate stents achieved the greatest percentage of stone weight loss when the drugs were completely released. LIMITATIONS: Ex vivo study. CONCLUSIONS: The EDTA and sodium cholate-eluting plastic stent effectively dissolved CBD stones and has prospect in the therapy for patients with difficult CBD stones.

[Neurologic complications in children with enterovirus 71-infected hand-foot-mouth disease : clinical features, MRI findings and follow-up study].

OBJECTIVE: To explore the clinical and magnetic resonance imaging (MRI) characteristics and the follow-up outcomes of neurologic complications in children with enterovirus 71-infected hand-foot-mouth disease. METHODS: The clinical and MRI manifestations and follow-up outcomes in 35 children, at Second Affiliated Hospital, Wenzhou Medical College from August 2008 to November 2010, hospitalized with neurologic complications of enterovirus 71-infected hand-foot-mouth disease were retrospectively analyzed. RESULTS: Six children with aseptic meningitis presented the clinical symptoms and signs of meningitis. Five of them showed subdural effusion and ventriculomegaly, or both on MRI. At follow-ups, neurologic sequel could not be found. Among 24 cases with brainstem encephalitis, there were myoclonic jerks and tremor, ataxia, or both (grade I disease, n = 12), myoclonus and cranial-nerve involvement (grade II disease, n = 4), and cardiopulmonary failure after brain-stem infection (grade III disease, n = 8). In patients with brainstem encephalitis, lesions were predominantly located at the posterior portions of medulla and pons with hypointensity on T1WI and hyperintensity on T2WI. Cerebellar dentate nucleus, caudate nucleus and lenticular nucleus could also be involved. At follow-ups, the patients with mild symptoms had no neurologic sequel and the lesions within brain stem became small or vanished in most cases. While in the majority of serious patients, neurologic sequel could be found and the lesions located at brain stem became encephalomalacia. Fourteen cases with acute flaccid paralysis presented acute limb myasthenia with tendon reflex and muscular tension decreased. On spinal MRI, the lesions predominantly involved anterior horn regions of spinal cord with hypointensity on T1WI and hyperintensity on T2WI. Most patients improved their muscle strength and most lesions of spinal cord became smaller or vanished during follow-ups. CONCLUSION: MRI is the most effective modality of diagnosis and follow-up for neurologic complications in children with enterovirus 71-infected hand-foot-mouth disease. On MRI, the lesions mainly involve the anterior horn of spinal cord, medulla oblongata and pons. At follow-ups, most patients have no neurologic sequel and the visualized lesions will be absorbed after active treatment.

[The effect of low-magnitude high-frequency loading on peri-implant bone healing and implant osseointegration in Beagle dogs].

PURPOSE: Low-magnitude, high-frequency（LMHF） loading has been confirmed to play an important role in bone healing. The present study aimed to evaluate the effect of LMHF loading applied directly to titanium dental implants on peri-implant bone healing and implant. METHODS: The mandibular premolars and molars were extracted from six male Beagle dogs. Three months post-extraction, six titanium implants (Aadva Standard Implant Narrow, 3.3 mm×8 mm) were inserted into the mandibular premolar and molar area (three implants per side) in each of the six dogs. In each animal, one side was randomly selected to undergo daily LMHF loading (experimental group), while the other side had no further intervention (control group). The loading was applied directly to the implant abutment using an individual jig and a custom-made loading device (8 µm,100 Hz). The implant stability quotient (ISQ) was tested every week. Three dogs were euthanized after 2 weeks, and three were euthanized after 8 weeks. Tissue samples were fixed and stained for micro-computed tomography(micro-CT) and histomorphometric analyses. The data were statistically analyzed using SPSS 13.0 software package. RESULTS: The experimental group had significantly increased peri-implant bone volume relative to tissue volume in region of interest 2 (100-500 µm) compared with the control group after 2 weeks of loading (P<0.05); however, there was no significant difference between the two groups after 8 weeks (P>0.05). The ISQ value and the micro-CT results did not differ between the two groups during the study period. CONCLUSIONS: LMHF loading positively influences peri-implant bone healing and osseointegration in the early healing period.

Drug-eluting fully covered self-expanding metal stent for dissolution of bile duct stones in vitro.

BACKGROUND: The treatment of difficult common bile duct stones (CBDS) remains a big challenge around the world. Biliary stenting is a widely accepted rescue method in patients with failed stone extraction under endoscopic retrograde cholangiopancreatography. Fully covered self-expanding metal stent (FCSEMS) has gained increasing attention in the management of difficult CBDS. AIM: To manufacture a drug-eluting FCSEMS, which can achieve controlled release of stone-dissolving agents and speed up the dissolution of CBDS. METHODS: Customized covered nitinol stents were adopted. Sodium cholate (SC) and disodium ethylene diamine tetraacetic acid (EDTA disodium, EDTA for short) were used as stone-dissolving agents. Three different types of drug-eluting stents were manufactured by dip coating (Stent I), coaxial electrospinning (Stent II), and dip coating combined with electrospinning (Stent III), respectively. The drug-release behavior and stone-dissolving efficacy of these stents were evaluated in vitro to sort out the best manufacturing method. And the selected stone-dissolving stents were further put into porcine CBD to evaluate their biosecurity. RESULTS: Stent I and Stent II had obvious burst release of drugs in the first 5 d while Stent III presented controlled and sustainable drug release for 30 d. In still buffer, the final stone mass-loss rate of each group was 5.19% ± 0.69% for naked FCSEMS, 20.37% ± 2.13% for Stent I, 24.57% ± 1.45% for Stent II, and 33.72% ± 0.67% for Stent III. In flowing bile, the final stone mass-loss rate of each group was 5.87% ± 0.25% for naked FCSEMS, 6.36% ± 0.48% for Stent I, 6.38% ± 0.37% for Stent II, and 8.15% ± 0.27% for Stent III. Stent III caused the most stone mass-loss no matter in still buffer or in flowing bile, which was significantly higher than those of other groups (P < 0.05). In vivo, Stent III made no difference from naked FCSEMS in serological analysis (P > 0.05) and histopathological examination (P > 0.05). CONCLUSION: The novel SC and EDTA-eluting FCSEMS is efficient in diminishing CBDS in vitro. When conventional endoscopic techniques fail to remove difficult CBDS, SC and EDTA-eluting FCSEMS implantation may be considered a promising alternative.

[Treatment of severe vertebral compressive fractures in the elderly with percutaneous vertebroplasty].

OBJECTIVE: To evaluate the efficacy of treating severe and chronic vertebral compressive fractures in the elderly with percutaneous vertebroplasty. METHODS: Sixteen patients who suffered from severe back pain and whose daily living was badly affected were retrospectively reviewed. The average age was 72.5 years, the average disease history was 19 months, and the average compressive rate of the affected vertebral bodies was 74.1%. RESULTS: Nineteen affected compressive vertebral bodies in 16 cases were treated with percutaneous vertebroplasty. All the procedures were successful without any complication. After 3.5-7 ml of cement was injected into the lesions, complete relief was achieved in 3 cases, remarkable relief was achieved in 11 cases, and improvement was observed in 2 cases. The scores of 6-point Behavioral Rating Scale and Activity of Daily Living (ADL) declined significantly after the treatment (P < 0.001). CONCLUSION: Percutaneous vertebroplasty can significantly improve the symptoms and quality of life in the elderly patients with severe and chronic vertebral compressive fractures.

[Effect of polylactic acid on the proliferation and differentiation of osteoblast-like cells].

OBJECTIVE: To assess the effects of polylactic acid (PLA) on the proliferation and differentiation of UMR-106 osteoblast-like cells. METHODS: The ultrastructures of the surface of untreated and pretreated PLA films were observed under electron microscope. UMR-106 osteoblast-like cells were cultured with PLA film which was untreated or treated by some special agents together, then the cells morphology was observed, and methyl thiazolyl tetrazolium (MTT) assay and alkaline phosphatase (ALP) analysis were performed to detect the Tiny distinction between the untreated film and pretreated film was proliferation and differentiation. RESULTS: found under electron microscope. The cells of material group were seen to have grown in clusters, compared with control. And the proportion of polygon and star cells was higher in the material group than in the control, The values measured by ALP and MTT in the material group were lower than control, yet the distinction was undulatory in different phase of test. The difference in cells morphology between the pretreatment group and control was observed only in the first three days. The values measured by ALP and MTT in the pretreatment group were almost consistent with those in control, and even slightly higher than control sometimes. CONCLUSION: PLA film does not have permanent inhibitory effect on the proliferation and differentiation of osteoblast-like cells. On the contrary, the treated PLA film may accelerate the proliferation and differentiation of cells to some extent. So, PLA film may have the potential for use as a good tissue-engineering frame in the treatment of bone disorders.

Embolization of brain arteriovenous malformations with ethylene vinyl alcohol copolymer: technical aspects.

BACKGROUND: Endovascular therapy plays an important role in the treatment of brain arteriovenous malformations (BAVMs). Ethylene vinyl alcohol copolymer (Onyx) is a novel liquid embolic material. This study aimed to summarize our experience of using Onyx for embolization of BAVMs with the focus on embolization technique. METHODS: From September 2003 to November 2007, 115 patients (43 women and 72 men, with a mean age of 29 years) with BAVMs were endovascularly treated with Onyx in our department. The following features of all AVMs were evaluated prior to treatment: type of nidus and shunt, draining veins, and feeding arteries. A total of 196 endovascular procedures were performed. RESULTS: The course of endovascular treatment was completed in 88 patients. Additional sessions were planned in 27 patients. Of the 88 patients, total occlusion was obtained in 23 patients (26.1%), near-total (> 80% of the original volume) occlusion was obtained in 35 patients (39.8%) and partial occlusion (< 80% of the original volume) was obtained in 30 patients (34.1%) using embolization as the sole therapeutic technique. Mean volume reduction was 72% (range 30% - 100%) in 115 patients. Thirty four patients (38.6%, 34/88) underwent radiosurgical treatment. Additional embolization sessions were planned in 27 patients. Complications occurred in 19 patients (16.5%, 19/115), leading to death in one patient (mortality 0.9%) and permanent disabling in 3 patients (morbidity 2.6%). CONCLUSIONS: Onyx was shown to be feasible and safe for embolization of BAVMs. Proper use of the Onyx injection technique largely improved the endovascular treatment of BAVMs. Large AVMs can be adequately reduced in size through the use of additional treatment.