Quan Huang

Vascular Geometry Change Because of Endovascular Stent Placement for Anterior Communicating Artery Aneurysms

BACKGROUND AND PURPOSE: Hemodynamics have been shown to play an important role in the initiation and progress of intracranial aneurysms, and are considered well-related to vascular configuration. The purpose of this study was to quantify the vascular geometry change due to intracranial stent placement and to discuss its potential effects on hemodynamics. MATERIALS AND METHODS: Imaging data of patients with wide-neck AcomA aneurysms, treated with stent-assisted coiling between January 2005 and January 2010, were retrospectively analyzed. The angle between the afferent vessels (A1 segment) and the efferent vessels (ipsilateral or contralateral A2 segment) was calculated to determine the exact change in the angle after stent placement. RESULTS: In all 20 patients, the stent caused a distinct change in the geometry of the parent vessel. Stent-related vascular angle change ranged from 7.60 to 74.88°, with an average of 29.95°. In 10 cases, the angle changed by >30°. In the 12 patients with the distal segment of the stent placed in the ipsilateral A2 segment, the mean postoperative A1-A2 angle increased by 27.71 ± 13.17° (from 7.60° to 48.29°). In the other 8 patients with the distal segment of the stent placed in the contralateral A2 segment, the mean postoperative A1-AcomA-A2 angle increased by 33.29 ± 21.89°(from 15.49° to 74.88°). CONCLUSIONS: In addition to serving as a scaffold to contain coils, stent placement for AcomA aneurysms has a substantial effect on the vascular geometry, which may result in local hemodynamic changes.

Stent-Assisted Embolization of Wide-Neck Anterior Communicating Artery Aneurysms: Review of 21 Consecutive Cases

BACKGROUND AND PURPOSE: Anterior communicating artery (AcomA) aneurysm is the most frequent form of aneurysm. Stent placement is particularly difficult and of limited use for AcomA aneurysms. We report our experience with stent-assisted embolization for wide-neck AcomA aneurysms in 21 patients. Particular attention is given to the morphologic characteristics and strategy of stent deployment. MATERIALS AND METHODS: Between January 2005 and February 2008, stent-assisted coiling was performed in 21 patients with wide-neck AcomA aneurysms. Patient demographics, aneurysm morphology, procedures, and clinical and angiographic outcomes were retrospectively reviewed. RESULTS: Successful deployment of the stent in the targeted artery was achieved in all patients. Nineteen Neuroform 2 or Neuroform 3 stents and 2 LEO stents were used. The distal segment of the stent was positioned in the ipsilateral A2 in 12 patients, in the contralateral A2 across the AcomA in 5 patients, and into the aneurysm sac in 4 patients. Complete occlusion was achieved in 18 patients; near-complete occlusion, in 2 patients; and partial occlusion, in 1 patient. Intraoperative perforation of the aneurysm developed in 1 patient, which was secured by subsequent coiling. Angiographic follow-up in 12 patients for 6.9 months showed 1 recanalization and no in-stent stenosis. CONCLUSIONS: Our preliminary results suggest that stent-assisted embolization for wide-neck AcomA aneurysms is technically feasible and safe. Further follow-up is needed for long-term efficacy of stent placement.

Endovascular treatment of wide-neck middle cerebral artery aneurysms with stents: a review of 16 cases.

BACKGROUND AND PURPOSE: MCA aneurysms are common and often pose technical challenges to interventionalists. Intracranial stents are widely used in treating wide-neck aneurysms in other locations. To evaluate the feasibility, effectiveness, and safety of stent placement in MCA aneurysms, we performed this retrospective study. MATERIALS AND METHODS: Between October 2003 and May 2009, 16 patients with 16 wide-neck MCA aneurysms were treated with stents at our institution. We retrospectively collected and analyzed the data for these patients, including demographics, morphologic features of the aneurysms, treatment results, and follow-up. RESULTS: Seventeen stents, including 12 Neuroform, 4 LEO, and 1 Enterprise, were successfully deployed in this series. Of the 13 aneurysms treated with stent-assisted embolization, complete occlusion was achieved in 9 aneurysms; residual neck remained in 1, and residual aneurysm was present in 3. Contrast stasis in the aneurysm sac was observed in the other 3 aneurysms treated with stent alone. Procedure-related complication occurred in 1 patient, leading to no permanent effect. The mRS score at discharge was 0–2 in 14 patients and 3–6 in 2. The angiographic follow-up results of 9 patients (mean, 5.6 months) showed that all aneurysms remained stable or improved; there was no in-stent stenosis, recurrence, or retreatment. The clinical follow-up (mean, 20.1 months) demonstrated no neurologic deterioration or rebleeding. CONCLUSIONS: Our preliminary experience demonstrates that stent placement for the treatment of selected wide-neck MCA aneurysms is feasible. However, its safety and efficacy should be further evaluated by larger case series and more adequate follow-up.

Trifolium-like Platinum Nanoparticle-Mediated Photothermal Therapy Inhibits Tumor Growth and Osteolysis in a Bone Metastasis Model

Bone metastasis is a frequent and fatal complication of cancer that lacks effective clinical treatment. Photothermal therapy represents a new strategy for the destruction of multiple cancers. In this study, trifolium-like platinum nanoparticles (TPNs) with small size and excellent photothermal conversion property are prepared via a facile and green method. TPNs show minimal cytotoxicity on normal cell lines and kill cancer cells upon exposure to a near-infrared light. These nanoparticles effectively inhibit tumor growth and prevent osteolysis in a bone metastasis model. This study offers a promising strategy in the treatment of bone metastasis.

REGg is critical for skin carcinogenesis by modulating the Wnt/b-catenin pathway

Here we report that mice deficient for the proteasome activator, REGγ, exhibit a marked resistance to TPA (12-O-tetradecanoyl-phorbol-13-acetate)-induced keratinocyte proliferation, epidermal hyperplasia and onset of papillomas compared with wild-type counterparts. Interestingly, a massive increase of REGγ in skin tissues or cells resulting from TPA induces activation of p38 mitogen-activated protein kinase (MAPK/p38). Blocking p38 MAPK activation prevents REGγ elevation in HaCaT cells with TPA treatment. AP-1, the downstream effector of MAPK/p38, directly binds to the REGγ promoter and activates its transcription in response to TPA stimulation. Furthermore, we find that REGγ activates Wnt/β-catenin signalling by degrading GSK-3β in vitro and in cells, increasing levels of CyclinD1 and c-Myc, the downstream targets of β-catenin. Conversely, MAPK/p38 inactivation or REGγ deletion prevents the increase of cyclinD1 and c-Myc by TPA. This study demonstrates that REGγ acts in skin tumorigenesis mediating MAPK/p38 activation of the Wnt/β-catenin pathway.

Wingspan Stents for the Treatment of Symptomatic Atherosclerotic Stenosis in Small Intracranial Vessels: Safety and Efficacy Evaluation

BACKGROUND AND PURPOSE: Until now, endovascular treatment of symptomatic atherosclerotic stenosis in small intracranial arteries (≤2.5 mm) was limited. We evaluated the safety and efficacy of the treatment by using Wingspan stents in arteries of this caliber. MATERIALS AND METHODS: From March 2007 to July 2010, 53 symptomatic intracranial stenoses with narrowing of at least 50% in 53 patients were treated by using Wingspan stents. Clinical manifestations and imaging features were recorded. RESULTS: The technical success rate was 98.1%. There were no serious complications, with the exception of 1 patient who experienced a small cerebral hemorrhage caused by perforation of microwire. Thirty-nine patients (74%) were available for follow-up imaging with DSA. ISR was documented in 13 of these patients, including 2 patients with symptomatic ISR. The median length of the vascular lesions was 5.39 mm, and patients whose vascular lesions were longer than 5.39 mm had a much higher incidence of ISR than patients whose vascular lesions were shorter than 5.39 mm (53% versus 15%, respectively). The median ratio of the reference artery diameter to the stent diameter was 0.78, and patients whose ratio was smaller than 0.78 had a much higher incidence of ISR than patients whose ratio was larger than 0.78 (53% versus 15%, respectively). CONCLUSIONS: In our series, percutaneous transluminal angioplasty and stent placement of small intracranial arteries by using Wingspan stents was safe. The ISR rate was relatively high; most patients having ISR were asymptomatic. Further follow-up is needed to assess the long-term efficacy of this procedure.

Primary chordomas of the cervical spine: a consecutive series of 14 surgically managed cases

OBJECT Cervical chordomas are rare lesions and usually bring about challenges in treatment planning because of their wide extension and complicated adjacent anatomy. There are few large published series at present focusing on cervical chordomas. The authors studied a consecutive series of 14 patients with primary cervical chordomas who underwent surgical treatment and were observed between 1989 and 2008. By reviewing the clinical patterns and follow-up data, they sought to investigate the clinical characters, tailor the appropriate surgical techniques, and establish prognosis factors for cervical chordomas. METHODS Hospitalization and follow-up data in the 14 patients were collected. All patients underwent piecemeal tumor excision and reconstruction for stability; total spondylectomy was achieved in 5 cases. Postoperative radiotherapy was administered in all patients. Kaplan-Meier plots were used to represent tumor recurrence and patient survival, and log-rank testing was used to determine the risk factors of local recurrence. RESULTS Follow-up ranged from 8 to 120 months (mean 58.6 months). Symptom and neural status in most patients improved after surgery. The 1- and 5-year disease-free survival rates were 78.6% and 50%, respectively, and the 1- and 5-year survival rates were 92.9% and 85.7%, respectively. Log-rank tests revealed that the following variables were significantly associated with a high rate of tumor recurrence: age less than 40 years or greater than 70 years (p = 0.006) and an upper cervical tumor location (p = 0.019). CONCLUSIONS Chordomas in the cervical spine are usually neoplasms that exhibit insidious growth and a wide extension by the time of diagnosis. Radical intralesional debulking surgery and postoperative radiotherapy have been effective treatment. A limited application of en bloc tumor resection and the highly likely intraoperative intralesional tumor seeding may partially explain the high local recurrence rate, whereas the chance of distant metastases, fortunately, is very low. Most recurrence were documented within 3 years. Some specific surgical techniques should be emphasized to minimize tumor seeding. Patients with upper cervical chordomas, younger adults, and elderly adults have worse prognosis. For patients with chordoma extending to both the anterior and posterior spinal columns, total spondylectomy combined with piecemeal excision is recommended for a better prognosis.

Use of Onyx for Transarterial Balloon-Assisted Embolization of Traumatic Carotid Cavernous Fistulas: A Report of 23 Cases

BACKGROUND AND PURPOSE: TCCFs are a common complication following craniofacial trauma and are usually treated by coils or detachable balloons. The use of the liquid embolic agent Onyx as the sole agent for the treatment of TCCFs has been rarely reported. Herein, we summarized the preliminary experience and effectiveness of treating TCCFs with Onyx in 23 patients. MATERIALS AND METHODS: From the 36 type A CCFs treated in our department between September 2005 and March 2011, a total of 23 posttraumatic direct CCFs were treated by using Onyx only via transarterial approach. RESULTS: Immediate postprocedural angiograms demonstrated complete occlusion in all patients. All the patients underwent a single procedure except 1 with bilateral TCCFs. Up to 24-month clinical and 3-month angiographic follow-ups revealed an ongoing complete occlusion without any complications. CONCLUSIONS: In this series, the use of Onyx for the transarterial embolization of TCCFs was feasible and effective. Associated adverse events were rare.

Nucleobase-modified dendrimers as nonviral vectors for efficient and low cytotoxic gene delivery.

Cationic dendrimers are associated with relatively low transfection efficacy and high toxicity in gene delivery. Surface modification of these dendrimers with functional ligands may resolve these issues. Here, we proposed a novel strategy to prepare surface-engineered dendrimers with high transfection efficacy and low toxicity on transfected cells. Several nucleobase analogues were modified on cationic dendrimers by a facile method. These nucleobase-modified dendrimers show improved transfection efficacy and reduced cytotoxicity compared to unmodified dendrimers on HEK293 and HeLa cells. Efficacy of the most efficient polymer is comparable to that of commercial transfection reagents such as SuperFect, PolyFect, and Lipofectamine 2000. The improved transfection efficacy of dendrimers after nucleobase modification is probably attributed to easier intracellular DNA unpacking and lower cytotoxicity. The results provide a valuable insight to guide the design of efficient and low cytotoxic gene vectors.

MDM2 knockdown mediated by a triazine-modified dendrimer in the treatment of non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and the five-year survival rate is lower in advanced NSCLC patients. Chemotherapy is a widely used strategy in NSCLC treatment, but is usually limited by poor therapeutic efficacy and adverse effects. Therefore, a new therapeutic regimen is needed for NSCLC treatment. Gene therapy is a new strategy in the treatment of NSCLC. However, the lack of efficient and low toxic vectors remains the major obstacle. Here, we developed a biocompatible dendrimer as a non-viral vector for the delivery of mouse double minute2 (MDM2) siRNA in vitro and in vivo to treat NSCLC. The triazine-modified dendrimer efficiently stimulates the down-regulation of MDM2 gene in NSCLC PC9 cells, which induces significant cell apoptosis through the activation of apoptosis markers such as caspase-8 and poly(ADP-ribose) polymerase (PARP) cleavage. Furthermore, the dendrimer/MDM2 siRNA polyplexes showed excellent activity in the inhibition of tumor growth in a PC9 xenograft tumor model. These results suggested that inhibition the expression of MDM2 might be a potential target in NSCLC treatment.