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Biomedical subjects

Zhong Qian

Publications and source records attributed to Zhong Qian.

14 recordsLinked to original sources
PubMed2006

Targeting vascular injury using Hantavirus-pseudotyped lentiviral vectors.

Restenosis is a pathological condition involving intimal hyperplasia and negative arterial remodeling. Gene therapy vectors have shown modest therapeutic effects, but the level of infectivity has been relatively poor. In the present study we have designed a modified lentiviral vector (LV) pseudotyped with a strain of Hantavirus (HTNV) to improve the transduction efficiency into vascular smooth muscle and endothelial cells in vitro and in vivo. In vivo studies using adult New Zealand White rabbits demonstrated that local delivery of HTNV-pseudotyped LV (2 x 10(7) TU) into balloon-injured carotid arteries led to highly efficient transduction into endothelial and smooth muscle cells more effectively than VSV-G-pseudotyped LV (2 x 10(7) TU) or replication-defective adenoviral vectors (1-1.5 x 10(9) pfu) as determined by beta-gal immunohistochemistry. Overexpression of extracellular superoxide dismutase in balloon-injured carotid arteries 6 weeks after LV administration resulted in a significant reduction (P = 0.0024) of the intima/media ratio (0.18 +/- 0.09; n = 4) compared to vehicle-infused carotid arteries (0.69 +/- 0.08; n = 7). No beta-gal immunostaining was detected in other systemic organs, including the spleen, liver, heart, lung, kidneys, and brain. Moreover, no changes in plasma alanine aminotransferase or aspartate aminotransferase were detected following LV administration. In all, these data show that LV pseudotyped with Hantaviral glycoproteins can be a useful vector for targeting therapeutic genes to the vasculature in vivo.

Angioplasty, Balloon↗
PubMed2005

A modified technique to minimize filter tilting during deployment of the Günther Tulip filter: in vitro study.

With an in vitro model of the inferior vena cava, it was demonstrated that slight tension on the introducer during quick release of the jugular Günther Tulip filter led to less tilting of the filter compared with the technique recommended by the manufacturer. This technique may be useful to minimize significant filter tilting that may be associated with decreased filtration efficiency, and difficulty or impossibility of future filter retrieval.

Blood Vessel Prosthesis Implantation↗
PubMed2005

Intimal dehiscence in the abdominal aorta following balloon fenestration for type B dissection.

PURPOSE: To report a case of intimal dehiscence associated with endovascular intervention in patients with aortic dissection. CASE REPORT: A 65-year-old man presented with a type B dissection extending to the level of the common iliac arteries. Two Talent stent-grafts were placed in the descending thoracic aorta to close the entry point, but 2 lumens remained. Three days later, abdominal pain prompted another imaging session, which demonstrated a large cylindrical filling defect in the abdominal aorta ("tube-in-tube") assumed to be a partially or completely dehisced intima. Fenestration marginally improved flow to the visceral vessels, and the patient improved clinically. However, 4 days later, recurrent ischemic symptoms prompted surgery; a complete dehiscence of the aortic intima starting at the descending aorta extended to the distal abdominal aorta. The aorta was resected, but the patient died from disseminated intravascular coagulation. CONCLUSIONS: Intimal flap dehiscence associated with an endovascular procedure in the management of aortic dissection is an uncommon complication. Early detection and prompt surgical intervention of such a complication could save the patient's life. Endovascular procedures are unlikely to resolve the hemodynamic problem caused by a dehisced, distally migrated, collapsed intima.

Aged↗
PubMed2005

Bifurcated endoprosthesis for treatment of aortoiliac occlusive lesions.

PURPOSE: To report our initial experience with a bifurcated endoprosthesis in the management of aortoiliac occlusive disease. METHODS: From May 2001 to February 2004, 112 patients were referred to our institution for the management of aortoiliac disease. Among these, 5 (6%) patients (3 men; mean age 57.8 years) with severe ischemia owing to TASC C or D iliac occlusions were selected for endovascular treatment with a bifurcated stent-graft. An Excluder stent-graft was placed after preliminary recanalization (thrombolysis and/or balloon dilation) the day before. The patients were followed clinically and ultrasonographically every 3 months during the first year and semiannually thereafter. RESULTS: Technical success was achieved in all patients. Endovascular aortoiliac bifurcation reconstruction restored iliac artery flow immediately in all cases. There were no procedure-related complications. The mean ankle-brachial index (ABI) was significantly improved, from 0.66+/-0.04 before the procedure to 0.94+/-0.06 immediately after the procedure (p<0.01). The aortoiliac reconstructions remained patent during the mean 17-month follow-up (range 3-36), and the ABIs were stable. There was no mortality or amputation required in this series. CONCLUSIONS: Endovascular placement of a bifurcated stent-graft appears to be technically feasible, effective, and safe in the management of aortoiliac occlusive disease.

Angioplasty, Balloon↗
PubMed2003

Percutaneous balloon angioplasty for the treatment of iliofemoral arterial stenosis resulting from hyperhomocysteinemia in a child.

Angioplasty has long been used in the treatment of peripheral arterial occlusive disease with variable long-term results. In this case report, we present a patient with marfanoid features and acute ischemia of the lower extremity. Angioplasty provided us with the means of emergently relieving the acute symptoms. The patient was subsequently found on further work-up to have hyperhomocysteinemia (HC) and appropriate medical therapy was initiated. We conclude that angioplasty should be considered in pediatric patients with acute occlusive limb ischemia, providing excellent immediate results to preserve the limb as well as the time to investigate the underlying causes.

Adolescent↗
PubMed2003

An animal model of abdominal aortic aneurysm created with peritoneal patch: technique and initial results.

The purpose of this study was to develop an abdominal aortic aneurysm model that more closely resembles the morphology of human aneurysms with potential for further growth of the sac. An infrarenal abdominal aortic aneurysm (AAA) model was created with a double-layered peritoneal patch in 27 domestic swine. The patch, measuring in average from 6 to 12 cm in length and from 2 to 3 cm in width, was sutured to the edge of an aortotomy. Pre- and postsurgical digital subtraction aortograms (DSA) were obtained to document the appearance and dimensions of the aneurysm. All animals were followed with DSA for up to 5 months. Laparoscopic examination enhanced by the use of laparoscopic ultrasound was also carried out in 2 animals to assess the aneurysm at 30 and 60 days following surgery. Histological examination was performed on 4 animals. All the animals that underwent the surgical creation of the AAA survived the surgical procedure. Postsurgical DSA demonstrated the presence of the AAA in all animals, defined as more than 50% increase in diameter. The aneurysmal mean diameter increased from the baseline of 10.27 +/- 1.24 to 16.69 +/- 2.29 mm immediately after surgery, to 27.6 +/- 6.59 mm at 14 days, 32.45 +/- 8.76 mm at 30 days (p < 0.01), and subsequently decreased to 25.98 +/- 3.75 mm at 60 days. A total of 15 animals died of aneurysmal rupture that occurred more frequently in the long aneurysms (> or =6 cm in length) than the short aneurysms (<6 cm in length) during the first 2 weeks after surgery (p <0.05). No rupture occurred beyond 16 days after surgery. Four animals survived and underwent 60-day angiographic follow-up. Laparoscopic follow-up showed strong pulses, a reddish external appearance and undetectable suture lines on the aneurysmal wall. On pathology, the patches were well incorporated into the aortic wall, the luminal wall appeared almost completely endothelialized, and cellular and matrix proliferation were noted in the aneurysmal wall. A reproducible technique for the creation of an infrarenal AAA model was developed using a peritoneal patch in swine. The aneurysm model proved to have potential for further growth of the sac and a tendency to rupture. Because of the growth potential, this might be a better model than those with a noncompliant aneurysmal wall for the preclinical evaluation of stent-graft devices.

Animals↗
PubMed2003

Computerized tomography guided percutaneous ethanol injection for the treatment of hyperfunctioning pheochromocytoma.

PURPOSE: We validated the therapeutic efficacy of computerized tomography (CT) guided percutaneous ethanol injection (PEI) for hyperfunctioning pheochromocytoma. MATERIALS AND METHODS: Pheochromocytoma was treated with CT guided PEI in 41 patients, including 19 men and 22 women with a mean age of 42 years (range 31 to 59). Of the 41 patients 40 had a solitary adrenal benign pheochromocytoma (18 on the left and 22 on the right side), which was diagnosed by biopsy in 36 and by typical clinical manifestations, laboratory and CT findings in 4. The remaining patient with malignant pheochromocytoma, who underwent surgical resection 2 years ago, had 2 recurrent lesions along the right sympathetic chain. RESULTS: CT or magnetic resonance imaging followup 7 to 20 days after treatment showed that adrenal benign pheochromocytoma disappeared in 27 patients and became completely necrotic or shrank in 13. The 2 malignant recurrent lesions also disappeared completely. During the followup of 23 to 54 months the foci disappeared completely in 31 patients, and shrank and completely necrotized in 10. All patients showed normal blood pressure without intermittent vertigo, complexion pallor or numbness of the 4 extremities. Blood and urine catecholamine was also within the normal range. CONCLUSIONS: The therapeutic efficacy of CT guided PEI for hyperfunctioning pheochromocytoma is definite and worth widespread application because the procedure is safe, microtraumatic and less costly, and has low morbidity.

Adrenal Gland Neoplasms↗
PubMed2003

Endovascular treatment of complicated type-B aortic dissection with stent-grafts:: midterm results.

PURPOSE: To report the midterm results of the endovascular treatment of complicated type-B aortic dissection with use of stent-grafts. MATERIALS AND METHODS: Ten patients with acute (n = 4) or chronic (n = 6) complicated type-B dissection were treated with custom-made stent-grafts. Indications for treatment included uncontrollable hypertension with dissection extension (n = 3), renal ischemia (n = 1), and false lumen aneurysm (n = 6). Stainless-steel Z-stents covered with polyester grafts were placed in the initial six patients. Nitinol stents covered with ultrathin polytetrafluoroethylene were used in the remaining four patients. The patients were followed-up with helical computed tomography for a maximum of 30 months (mean, 20 mo). RESULTS: There was one technical failure related to the access site. Early complications included deep venous thrombosis (n = 1) and embolic stroke (n = 1). Complete thrombosis of the thoracic false lumen was achieved in six patients and partial thrombosis was achieved in three. Aneurysms developed at the ends of the stainless-steel stents in two patients, requiring additional stent-graft placement. Despite successful remodeling of the thoracic aorta, three of four patients with distal reentry into the abdominal aorta experienced progressive abdominal aortic aneurysm (AAA). AAA rupture developed in two patients; one rupture was fatal and the other was treated with emergency surgery. CONCLUSIONS: Endovascular treatment of complicated type-B aortic dissection is technically feasible and effective. Closely monitoring the treated aorta is essential to detect early aneurysm formation at the ends of rigid stents. Despite adequate sealing of the tears in the thoracic aorta, dissection with distal reentry phenomenon into the abdominal aorta may evolve into AAA with late rupture.

Alloys↗
PubMed2003

CT-guided percutaneous ethanol injection of the thymus for treatment of myasthenia gravis.

OBJECTIVE: This study was designed to validate the therapeutic effectiveness of CT-guided percutaneous ethanol injection of the thymus for the treatment of myasthenia gravis. SUBJECTS AND METHODS: The subjects were 45 patients with myasthenia gravis. The diagnosis was determined by the patients' histories, physical findings, neostigmine tests, and morphologic changes. According to the Osserman classification, the 45 patients with myasthenia gravis were classified as stage I (n = 26), stage III (n = 13), and stage IV (n = 6). A 21- or 22-gauge needle was inserted into the thymus under CT guidance, and then ethanol was injected step by step until it was distributed throughout the whole thymoma, the hyperplasia of the thymus, or the normal thymus. The amount of ethanol injected ranged from 2 to 13 mL, with a mean of 7 mL. RESULTS: CT follow-up at 3-4 weeks showed that the thymus or thymoma was completely or mostly necrotized. CT follow-up at 3 months showed that the vertical, transverse, and anteroposterior dimensions of the thymus in all 45 myasthenia gravis patients decreased by 59.2%, 68.6%, and 73.2%, respectively, compared with those before percutaneous ethanol injection treatment. The therapeutic effect was observable clinically 2 days after treatment in 44 patients, including 36 patients who were able to open their eyes after treatment. A 5-year follow-up study showed that the condition markedly improved in 35 patients, improved in nine patients, and failed to improve in one patient who did not respond to the treatment. After treatment, 37 patients presented with low-grade fever (range, 37.3-37.7 degrees C; mean, 37.5 degrees C), which resolved 3 days later without treatment; all 45 patients complained of mild retrosternal pain after ethanol injection. CONCLUSION: The therapeutic effect of CT-guided percutaneous ethanol injection into the thymus of patients with myasthenia gravis is definite. This procedure is safe and has low morbidity. CT-guided percutaneous ethanol injection is a minimally invasive alternative treatment for myasthenia gravis.

Adolescent↗
PubMed2002

Comparison of a new recirculation thrombectomy catheter with other devices of the same type: in vitro and in vivo evaluations.

RATIONALE AND OBJECTIVES: To compare a new 7 Fr. Helix thrombectomy catheter with Amplatz thrombectomy devices (ATD) with respect to clot fragmentation efficiency, hemolytic potential, and risk for vascular trauma. MATERIALS AND METHODS: Particle size was evaluated following the maceration of 8-to-10-day-old clots, each weighing 6 +/- 0.01 g. The clots were macerated using devices of various sizes, including the 7-Fr. Helix thrombectomy catheter, the 7-Fr. over-the-wire (OTW), 8-Fr. ATD and the 6-Fr. ATD. The number of particles by weight was quantified. The 7-Fr. Helix and the 8-Fr. ATD were tested in the native iliac vein of six dogs without presence of clots. Blood samples were obtained before, during, and at 1, 3, 6, 24, and 48 hours after the procedure, to monitor the hemolytic effects. The treated iliac veins were examined histologically. RESULTS: Most of the clot was fragmented into particles <10 microm. The mean percentage by weight of the original clot that remained as particles larger than 10 microm was 1.59% in the 7-Fr. Helix group. This was significantly less than 3.10% with the 6-Fr. ATD, 2.57% with 7-Fr. OTW and 2.44% in the 8-Fr. ATD group (<0.01). In vivo results showed a higher plasma free hemoglobin (PFH) level starting 5 minutes after initiating the ATD activation, reaching its peak after completion of the activation, and declining afterward, with return to the baseline at 24 hours. The haptoglobin level tended to decline slightly at 10 minutes, reaching its lowest level at 24 hours, and starting to recover at 48 hours. A similar pattern of PFH and haptoglobin changes was found in both groups. There were no significant differences regarding hemolytic effect of the two tested devices. No significant changes of creatinine were observed for up to 48 hours after procedures. Focal microthrombosis was seen in two sites of two vessels treated with the 7-Fr. Helix and a focal injury of a venous valve was noted in the 8-Fr. ATD group. The media and internal elastic lamina (IEL) were intact in all cases. CONCLUSION: The newly designed 7-Fr. Helix is more effective in fragmentation in vitro clots than the 6 Fr. ATD, 7-Fr. OTW and the 8-Fr. ATD. The 7-Fr. Helix and the 8-Fr. ATD produced hemolytic effects, but they appeared to be tolerated by the animals. The in vivo results indicated that the 7-Fr. Helix appears to be as safe as the 8-Fr. ATD.

Animals↗
PubMedDate not supplied

Endovascular placement of an extraluminal femoropopliteal bypass graft in human cadavers.

PURPOSE: A method to create an extraluminal femoropopliteal bypass graft using endovascular techniques was evaluated in situ on cadaver extremities in an attempt to develop a minimally invasive alternative technique for the management of infrainguinal occlusive arterial disease. METHODS: The endovascular placement of an extraluminal femoropopliteal bypass graft was undertaken in 5 cadaver legs. Following percutaneous access to the popliteal artery (PA) or common femoral artery (CFA), a Rosch-Uchida needle was used to perforate the vascular wall, followed by the creation of an extraluminal tract using a looped wire and catheter. Once the desired level was reached the needle was again used to perforate the vascular wall of the proximal superficial femoral artery (SFA) or PA depending on the access used. Self-expanding expanded polytetrafluoroethylene (ePTFE) stent-grafts were then deployed to establish the extraluminal femoropopliteal bypass connecting the two arterial puncture sites. Following dilatation of the stent-graft, angiography was performed to assess the endoprostheses and to look for contrast leaks. RESULTS: Technical success was achieved in all 5 legs. Procedure time varied from 15 to 30 min. The angiographic studies performed immediately after completion of the bypass procedure showed patency of the grafts with no evidence of kinking or leakage in any of the cases. CONCLUSION: This study has proved that the endovascular placement of an extraluminal femoropopliteal bypass graft in human cadaver legs using endovascular techniques under fluoroscopic control is technically feasible.

Angiography↗
PubMedDate not supplied

Percutaneous transcholecystic biliary interventions using gallbladder anchors: feasibility study in the swine.

The purpose of this study was to report our initial experience with a swine model for biliary interventions by using a percutaneous transcholecystic access after suture anchor of the gallbladder. Telepaque tablets were given to five pigs to opacify the gallbladder. Under fluoroscopy, the opacified gallbladder was punctured percutaneously and three suture anchors were used to fix the anterior wall of the gallbladder to the abdominal wall. Two weeks later, the gallbladder was punctured and access into the distal common bile was obtained through the cystic duct. Balloon expandable stents were deployed into the distal common bile duct. Follow-up cholangiograms were obtained at 1 and 2 weeks. Necropsy was performed after 2 weeks to evaluate the relationship between the gallbladder and abdominal wall. Suture anchor placement was successful in all five pigs. One pig with a deep and highly positioned gallbladder developed fever, anorexia, and vomiting secondary to excessive stretch of the gallbladder. Placement of the guidewire through the extremely tortuous and small cystic ducts proved to be the most challenging step of the procedure. Metallic stents were successfully deployed in all four pigs in which it was attempted. Four animals tolerated the procedures without changes in their clinical conditions and no symptoms. Successful follow-up cholangiograms were performed at 1 and 2 weeks post-stent deployment without complications. All stents remained patent during the follow-up period. Necropsy demonstrated close attachment and adherence of the gallbladders to the antero-lateral abdominal wall in all four animals. Suture anchoring of the gallbladder is feasible in most pigs with superficially located gallbladders. This technique allows a safe and repeat access into the biliary system using a transcholecystic approach.

Animals↗