Taeseung Lee

Effect of nicotine on human umbilical vein endothelial cells (HUVECs) migration and angiogenesis

The effects of nicotine on vascular endothelial cells have not been completely elucidated. We performed this study to assess the changes in cellular behaviors of human umbilical vein endothelial cells (HUVECs) treated with nicotine. We examined changes in cell count and morphology and assayed cellular migration with Boyden chamber and microcapillary tube formation in a Matrigel matrix following treatment with various concentrations of nicotine. Compared to the control, nicotine stimulated cell proliferation, migration, and tube formation at concentrations similar to those found in smokers. Although there were no specific morphological changes in HUVECs treated with nicotine at the concentration similar to that in smokers, at high concentration (10(-4) M), morphological changes such as cytoplasmic vacuolization and irregular cell shape were observed, which were assumed to be the result of direct cytotoxicity of nicotine. In HUVECs, nicotine enhanced cellular proliferation, migration and angiogenesis in vitro, and thus caused a functional change, not a morphological change at a concentration similar to that in habitual smokers.

Restoration of Patency in Iliofemoral Deep Vein Thrombosis with Catheter-Directed Thrombolysis Does Not Always Prevent Post-Thrombotic Damage

OBJECTIVESnTo evaluate the long-term results of catheter-directed thrombolysis (CDT) and the feasibility of stent placement for lower extremity deep vein thrombosis (DVT).nnnDESIGN & METHODSnRetrospective study of 34 patients (10 men and 24 women, mean age 55, S.D. 13 years) with lower extremity DVT underwent CDT at Seoul National University Hospital from January 1999 to October 2003. Patient characteristics, risk factors of DVT, extent of thrombosis, and short-term and long-term results of CDT and/or stent placement were analysed.nnnRESULTSnMean follow-up times were 47 S.D. 16 months. The primary technical success rate was 97% (complete lysis 68%, partial 29%). During the follow-up periods 11 (32%) patients showed re-thrombosis. Sixteen (47%) of 34 patients showed chronic change of vessels during the follow-up periods. By Cox Proportional Hazard analysis, extent of thrombolysis was a statistically significant factor affecting the freedom of re-thrombosis and chronic change (P=0.008 and P=0.001). Nine (44%) of 21 deployed stents were obstructed, and the overall stent patency at 3 years was 56.7%. The only factor affecting the stent patency was stent length more than 6 cm (P=0.002, HR 13, 95% CI 2.7-59).nnnCONCLUSIONnLong-term results of CDT are not satisfactory because of the high recurrence rate of DVT and it cannot prevent chronic post-thrombotic damage to the affected vessels despite long-term anticoagulation therapy. Careful long-term surveillance of the venous function is highly recommended after CDT.

Effects of xylulokinase activity on ethanol production from d‐xylulose by recombinant Saccharomyces cerevisiae

Aims: Recombinant Saccharomyces cerevisiae strains harbouring different levels of xylulokinase (XK) activity and effects of XK activity on utilization of xylulose were studied in batch and fed‐batch cultures.

Role of three-dimensional computed tomography venography as a powerful navigator for varicose vein surgery

PURPOSEnComputed tomography venography (CTV) with three-dimensional reconstruction can provide complementary road maps for varicose vein (VV) surgery. The purpose of this study is to verify the role of CTV in the treatment of VV in terms of advantages and complications.nnnMETHODSnNinety-four consecutive patients with VV underwent conventional high ligation, stripping, and varicosectomy by a single vascular surgeon in 2007. All patients were evaluated with duplex ultrasound and CTV. Patients with renal dysfunction, allergy to radiocontrast, telangiectasia only, or treated by endovenous laser therapy (EVLT) were excluded from the study. Computed tomography (CT) examination was performed with a 16-Multidetector CT scanner (Siemens, Erlangen, Germany) and 3D images were reconstructed by personal computer-based software (Rapidia, Infinitt, Seoul, Korea). Medical records and the CT images were reviewed retrospectively.nnnRESULTSnVV surgeries were done in 127 limbs of 94 patients (both in 33, right in 29, and left in 32). There were 56 females and 38 males with the mean age of 57 years (range, 28-79 years). The CEAP classification was C(2-3) EpAsPr. Perforators larger than 1 mm near the varicose veins were detected and marked on the CT volume-rendering images. The average numbers of perforators marked by CTV were 12.07 +/- 4.27 in each limb. The perforators were evaluated by duplex for the presence of reflux (>or=0.5 sec). Mean number of perforators with reflux in each limb was 1.41 +/- 1.67, which were ligated during the surgery. Incidental detections of other disease were done in six patients, including uterine myomas, an ovarian cyst, a gallstone, a scrotoal varicocele, and a pes anserine bursitis. Operation was performed with the CTV images on screen. CTV was helpful in designing the operation in most patients. Three-D CTV images of saphenopopliteal junction especially provided thorough understanding of the complex variable anatomy of the lesion. There were no CT-related complications, such as renal dysfunction or allergic reaction.nnnCONCLUSIONSnCT venography can provide excellent road map for VV surgery without significant complications. It cannot replace duplex ultrasound, but can provide powerful 3D images for designing operation as well as education and research.

Risk factors associated with amputation-free survival in patient with diabetic foot ulcers.

Purpose To determine the 1-year survival rate, 1-year amputation-free survival rate and the risk factors of amputation for patients with diabetic foot ulcers. Materials and Methods One hundred seventy-three patients with diabetic foot ulcers were included in our study. Mean patient age was 67.5 (range, 29 to 87, SD ±11.4) years. 74% of the patients were male. Time from study entry to amputation and time to death were evaluated separately as censored event times by Kaplan-Meier curves and log-rank tests. A multivariate Cox proportional hazards regression analysis was carried out for determining the risk factors of amputation. Results The survival rate and amputation-free survival rate were 96.5% (n=167), 65.9% (n=114), respectively, over one year study period. Severity of ulcer was the strongest significant risk factor of amputation [hazard ratio (HR): 7.99; confidence interval (CI): 3.12 to 20.47]. Peripheral artery disease was also independent risk factor of amputation (HR: 2.64; CI: 1.52 to 4.59). Conclusion In assessing the prognosis of diabetic foot ulcers, clinicians should consider the severity of ulcer and presence of peripheral artery disease. Our study provides important insights into clinical practice and supplementary information for both physicians and patients.

Potential role of vascular smooth muscle cell-like progenitor cell therapy in the suppression of experimental abdominal aortic aneurysms

Abdominal aortic aneurysms (AAA) are a growing problem worldwide, yet there is no known medical therapy. The pathogenesis involves degradation of the elastic lamina by two combined mechanisms: increased degradation of elastin by matrix metalloproteinases (MMP) and decreased formation of elastin due to apoptosis of vascular smooth muscle cells (VSMC). In this study, we set out to examine the potential role of stem cells in the attenuation of AAA formation by inhibition of these pathogenetic mechanisms. Muscle-derived stem cells from murine skeletal muscles were isolated and stimulated with PDGF-BB in vitro for differentiation to VSMC-like progenitor cells (VSMC-PC). These cells were implanted in to elastase-induced AAAs in rats. The cell therapy group had decreased rate of aneurysm formation compared to control, and MMP expression at the genetic, protein and enzymatic level were also significantly decreased. Furthermore, direct implantation of VSMC-PCs in the intima of harvested aortas was visualized under immunofluorescent staining, suggesting that these cells were responsible for the inhibition of MMPs and consequent attenuation of AAA formation. These results show a promising role of stem cell therapy for the treatment of AAAs, and with further studies, may be able to reach clinical significance.

Midterm Results of Radiofrequency Ablation for Incompetent Small Saphenous Vein in Terms of Recanalization and Sural Neuritis

BACKGROUND Safety and effectiveness of radiofrequency ablation for incompetent small saphenous vein is not established. OBJECTIVE To report midterm clinical and ultrasonograhic results of radiofrequency ablation (RFA) for small saphenous vein (SSV) in terms of recanalization and sural neuritis. METHODS AND MATERIALS We examined 39 patients (46 limbs) who had been examined using a duplex scan more than 1 year after RFA of SSV. Postoperative clinical results, risk factors for SSV recanalization, and sural neuritis were analyzed. RESULTS CEAP score and CIVIQ2 score improved significantly in all patients (CEAP: 2.45 to 1.43 (p = .03); CIVIQ2: 25.34 to 13.21 (p = .01). SSV obliteration rate was 93.4% at 1 year and 89.1% at 2 years. Preoperative peak reflux velocity in the recanalization group (54.9 cm/s) was significantly higher (p < .01) than in the obliteration group (29.8 cm/s). Sural neuritis were detected in 12 limbs (26.1%), and median symptom duration was 3 months. The total length of RFA ablation was not different between the groups with and without postablation sural neuritis. CONCLUSION RFA is an effective and safe treatment modality for incompetent SSV. Peak reflux velocity can be a risk factor for recanalization. Length of RFA segment in SSV does not affect recanalization and postablation sural neuritis.

Consensus for the Treatment of Varicose Vein with Radiofrequency Ablation

The objective of this paper is to introduce the schematic protocol of radiofrequency (RF) ablation for the treatment of varicose veins. Indication: anatomic or pathophysiologic indication includes venous diameter within 2–20 mm, reflux time ≥0.5 seconds and distance from the skin ≥5 mm or subfascial location. Access: it is recommended to access at or above the knee joint for great saphenous vein and above the mid-calf for small saphenous vein. Catheter placement: the catheter tip should be placed 2.0 cm inferior to the saphenofemoral or saphenopopliteal junction. Endovenous heat-induced thrombosis ≥class III should be treated with low-molecular weight heparin. Tumescent solution: the composition of solution can be variable (e.g., 2% lidocaine 20 mL+500 mL normal saline+bicarbonate 2.5 mL with/without epinephrine). Infiltration can be done from each direction. Ablation: two cycles’ ablation for the first proximal segment of saphenous vein and the segment with the incompetent perforators is recommended. The other segments should be ablated one time. During RF energy delivery, it is recommended to apply external compression. Concomitant procedure: It is recommended to do simultaneously ambulatory phlebectomy. For sclerotherapy, it is recommended to defer at least 2 weeks. Post-procedural management: post-procedural ambulation is encouraged to reduce the thrombotic complications. Compression stocking should be applied for at least 7 days. Minor daily activity is not limited, but strenuous activities should be avoided for 2 weeks. It is suggested to take showers after 24 hours and tub baths, swimming, or soaking in water after 2 weeks.

Two-port laparoscopic placement of a peritoneal dialysis catheter with abdominal wall fixation

We devised a new laparoscopic technique for peritoneal dialysis catheter (PDC) placement to overcome the common problem of malfunction or migration of the catheter. Between March 2005 and August 2006, 38 patients underwent laparoscopic catheter placement with lower abdominal wall fixation. Using an abdominal scout film, we checked for catheter tip migration regularly. There was no leak in the immediate postoperative period. After follow-up of 21.5 months (range 6–34), all catheters were working properly, although tip migrations were found in the iliac fossa in three patients and in the right upper quadrant in one patient. A port site hernia developed in one patient and peritonitis developed in two patients. Only one remote migration (2.6%) occurred during the study period. Thus, our method of laparoscopic catheter insertion might be a feasible option.

Expression of cell cycle regulators during smooth muscle cell proliferation after balloon catheter injury of rat artery.

Intimal hyperplasia is defined as the abnormal migration and proliferation of vascular smooth muscle cells (VSMCs) with deposition of extracellular matrix. However, the cell cycle regulatory mechanisms of injury-induced VSMC proliferation are largely unknown. To examine the expression kinetics of cell cycle regulatory factors which is known to be worked positively or negatively, we used rat balloon injury model. Marked induction of proliferating cell nuclear antigen (PCNA), G1/S cyclin-dependent kinase (cdk2), and its regulatory subunit (cyclin E) occurred between 1 and 3 days after balloon arterial injury, and this was sustained for up to 7 days and then declined. However, the induction of the negative regulators, p21 and p27, occurred between 3 and 5 days of injury, peaked after 7 and 14 days and was then sustained. VSMC proliferation after balloon catheter injury of the rat iliac artery is associated with coordinated expression of positive (cdk2, cyclin E and PCNA) and negative (p21, p27) regulators. Cell cycle regulators such as cdk2, cyclin E, p21, p27 may be suitable targets for the control of intimal hyperplasia.