Jung-Hoon Park

Microalbuminuria is associated with the insulin resistance syndrome independent of hypertension and type 2 diabetes in the Korean population

To investigate whether microalbuminuria is associated with the insulin resistance syndrome independent of hypertension and type 2 diabetes, we studied the association between microalbuminuria and features of insulin resistance syndrome in Korean general population. We selected 1006 subjects by a random cluster sampling among residents aged >40 years living in the Chung-Up district, a rural area of South Korea. Subjects were stratified by oral glucose tolerance status [normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and diabetes mellitus], and by the presence or absence of hypertension. Urinary albumin excretion rate (UAER) was determined using timed overnight urine collection. Various cardiovascular risk factors including anthropometric indices, serum lipid, true insulin and proinsulin concentrations were also measured. The prevalence of microalbuminuria (UAER between 20 and 200 microg/min) increased as the glucose tolerance worsened (6.0% in NGT, 11.8% in IGT, and 21.8% in diabetes; chi(2) trend=25.9, P<0.001). Subjects with microalbuminuria had a higher body mass index (BMI), waist-to-hip circumference ratio (WHR), systolic and diastolic blood pressure (BP), fasting and 2 h plasma glucose, fasting plasma insulin and proinsulin levels, and lower HDL-cholesterol level than subjects without microalbuminuria. In multiple regression analysis, BMI, diastolic BP, 2 h plasma glucose, and fasting plasma insulin levels were found to be independent factors associated with UAER. Multiple logistic regression analysis showed that not only diabetes mellitus and hypertension, but also fasting hyperinsulinemia and waist-to-hip ratio were independent factors associated with the presence of microalbuminuria. When the normotensive, non-diabetic subjects were analyzed separately, fasting hyperinsulinemia and impaired glucose tolerance remained independent variables associated with the presence of microalbuminuria. These results show that microalbuminuria in the Korean general population is associated with hyperinsulinemia and central obesity, and suggest that microalbuminuria is a feature of the insulin resistance syndrome independent of hypertension or type 2 diabetes.

Association between birth weight and insulin sensitivity in healthy young men in Korea: role of visceral adiposity.

Recent studies have demonstrated decreased insulin sensitivity in individuals with low birth weight. This study was performed to examine whether abdominal obesity is a link between insulin resistance and low birth weight. We studied the relationships between birth weight and insulin secretion, insulin sensitivity, and various anthropometric indices including visceral fat area in 22 healthy young Korean adults. Birth weight correlated significantly with diastolic blood pressure (r=-0.47, P<0.05) and insulin sensitivity index (S(I)) measured by a frequently sampled intravenous glucose tolerance test (FSIGT) (r=0.54, P<0.05), but not with insulin secretory indices such as acute insulin responses during FSIGT (r=-0.35, NS) or hyperglycemic clamp (r=0.17, NS) and submaximum insulin response during hyperglycemic clamp (r=0.10, NS). S(I) correlated significantly with abdominal obesity measurements such as waist circumference (r=-0.48, P<0.05), waist-to-hip ratio (r=-0.53, P<0.05) and visceral fat area (r=-0.58, P<0.01). However, we could not find significant correlation between birth weight and any of the abdominal obesity measurements (r=-0.35 for waist-to-hip ratio, r=-0.22 for visceral fat area, and r=-0.24 for visceral-to-subcutaneous fat ratio; NS for all). The present data confirm that low birth weight is associated with insulin resistance in adult life. However, our data suggest that the association between low birth weight and insulin resistance is not mediated by abdominal obesity.

Prevalence and clinical characteristics of metabolic syndrome in a rural population of South Korea

Aims  To determine the prevalence of metabolic syndrome according to the criteria of the Adult Treatment Panel III (ATP III) and the World Health Organization (WHO).

The effects of the overexpression of recombinant uncoupling protein 2 on proliferation, migration and plasminogen activator inhibitor 1 expression in human vascular smooth muscle cells

Aims/hypothesisIncreased oxidative stress in vascular smooth muscle cells (VSMCs) has been implicated in the pathogenesis of accelerated atherosclerosis in patients with diabetes mellitus. Uncoupling protein 2 (UCP-2) is an important regulator of intracellular reactive oxygen species (ROS) production. We hypothesised that UCP-2 functions as an inhibitor of the atherosclerotic process in VSMCs.MethodsOverexpression of human UCP-2 was performed in primary cultured human VSMCs (HVSMCs) via adenovirus-mediated gene transfer. Its effects on ROS production, AP-1 activity, plasminogen activator inhibitor 1 (PAI-1) gene expression, and cellular proliferation and migration were measured in response to high glucose and angiotensin II (Ang II) concentrations, two major factors in the pathogenesis of atherosclerosis in patients with diabetes and hypertension. Mitochondrial membrane potential and NAD(P)H oxidase activity were also measured.ResultsHigh glucose and Ang II caused transient mitochondrial membrane hyperpolarisation. They also significantly stimulated ROS production, NAD(P)H oxidase activity, mitochondrial membrane potential, AP-1 activity, PAI-1 mRNA expression, and proliferation and migration of HVSMCs. Adenovirus-mediated transfer of the UCP-2 gene reversed all of these effects.Conclusions/interpretationThe present study demonstrates that UCP-2 can modify atherosclerotic processes in HVSMCs in response to high glucose and Ang II. Our data suggest that agents increasing UCP-2 expression in vascular cells may help prevent the development and progression of atherosclerosis in patients with diabetes and hypertension.

Benign Anastomotic Strictures After Esophagectomy: Long-Term Effectiveness of Balloon Dilation and Factors Affecting Recurrence in 155 Patients

OBJECTIVE The purpose of this article is to retrospectively evaluate the long-term clinical results of balloon dilation in the treatment of benign anastomotic strictures after esophagectomy and to identify factors associated with stricture recurrence. MATERIALS AND METHODS From January 1996 to June 2011, a total of 309 sessions of balloon dilation were performed in 155 patients with benign anastomotic strictures after esophagectomy. Long-term clinical effectiveness was assessed using the following variables: technical and clinical success, complications, and patency rates. Factors independently related to recurrence were evaluated with the Cox model. Tested variables were age, sex, operation type, postoperative anastomotic leakage, balloon size, length of stricture, time to postoperative stricture development, complications, and neoadjuvant chemoradiotherapy. RESULTS The mean follow-up period was 37 months (range, 1-159 months). Overall clinical success was achieved in 153 patients (99%) after a single (n = 78) or multiple (n = 75) balloon dilations. During follow-up, recurrence of the stricture requiring repeated dilation was seen in 77 of 155 patients (50%). Esophageal rupture (mostly intramural rupture) occurred in 22 of 155 patients (14%) and 34 of 309 balloon dilations (11%). In multivariate analysis, early development of stricture within 10 weeks after surgery (p = 0.002) and McKeown esophagectomy (p = 0.002) were independently related to recurrence after initial balloon dilation. CONCLUSION Balloon dilation under fluoroscopic guidance has encouraging long-term results in the treatment of benign anastomotic strictures after esophagectomy. However, recurrence after balloon dilation was common, with McKeown esophagectomy and development of stricture within 10 weeks after surgery associated with recurrent strictures.

IN-1233, an ALK-5 Inhibitor: Prevention of Granulation Tissue Formation after Bare Metallic Stent Placement in a Rat Urethral Model

PURPOSE To evaluate the efficacy of an activin receptor-like kinase-5 inhibitor, IN-1233, for the prevention of tissue hyperplasia after bare stent placement in a rat urethral model. MATERIALS AND METHODS Procedures were performed in accordance with the National Institutes of Health guidelines for humane handling of animals; approval of the committee of animal research was obtained. In 20 Sprague-Dawley male rats (weight range, 300-350 g), a self-expanding metallic bare stent was inserted in the urethra by using fluoroscopic guidance. One group of 10 rats (group A) was treated with IN-1233, the other group of 10 rats (group B) received no treatment. Retrograde urethrography was performed 4 and 8 weeks after stent placement. All rats were sacrificed at 8 weeks for histologic analysis. RESULTS Stent placement was technically successful in all rats. The average stent diameter was significantly larger in group A compared with group B at follow-up retrograde urethrography performed 4 (P = .006) and 8 (P < .001) weeks after stent placement. At histologic analysis, the percentage of granulation tissue area (P < .001), thickness of submucosal fibrosis (P < .001), and number of epithelial layers (P < .001) were significantly decreased in group A compared with group B. Inflammatory cell infiltration (P < .001) was significantly increased in group A compared with group B. CONCLUSION IN-1233 is effective for the prevention of granulation tissue formation after bare metallic stent placement in a rat urethral model.

Dual-Design Expandable Colorectal Stent for Malignant Colorectal Obstruction: Comparison of Flared Ends and Bent Ends

OBJECTIVE The purpose of this study was to compare, focusing on colonic perforation and stent migration, the clinical safety and efficacy of dual-design expandable colorectal stents with flared ends with those of stents with bent ends in the treatment of patients with malignant colorectal obstruction. SUBJECTS AND METHODS A total of 122 patients with malignant colorectal obstruction underwent implantation of dual-design stents with flared (n = 69) or bent (n = 53) ends. RESULTS Stent placement was technically successful in 116 of 122 patients (95.1%), 65 of 69 patients (94.2%) with flared-end stents and 51 of 53 patients (96.2%) with bent-end stents (p > 0.05). Clinical success was achieved within 2 days in 61 of 65 patients (93.8%) with bent-end stents and in 46 of 51 patients (90.2%) with flared-end stents (p > 0.05). Complications included seven cases of colonic perforation (6%), seven cases of stent migration (6%), three cases of tumor overgrowth (2.6%), four cases of severe rectal pain (3.4%), and four cases of bleeding (3.4%). There were no significant differences between the rates of colonic perforation and stent migration in the two groups (6.2% vs 5.9%), and the overall complication rates were similar (p > 0.05). CONCLUSION Dual-design expandable colorectal stents with flared ends and those with bent ends are equally safe and effective, having similar perforation and migration rates.

Tumor Overgrowth After Expandable Metallic Stent Placement: Experience in 583 Patients With Malignant Gastroduodenal Obstruction

OBJECTIVE The objective of our study was to assess the incidence, predictive factors, and treatment of tumor overgrowth after placement of expandable metallic dual stents in patients with malignant gastroduodenal obstruction. MATERIALS AND METHODS Expandable metallic dual stents were inserted under fluoroscopic guidance in 583 patients with symptomatic malignant gastroduodenal obstruction. We retrospectively reviewed prospectively collected patient records to determine the incidence and treatment of tumor overgrowth after stent placement and used multivariate analysis to determine factors predicting tumor overgrowth. RESULTS Tumor overgrowth occurred after stent placement in 22 of 583 patients (3.8%) (range, 41-634 days; mean, 179.0 days). Duodenal lesions (odds ratio [OR], 4.505; p = 0.002), longer survival time (OR, 1.003; p = 0.001), and length of obstruction (OR, 0.783; p = 0.035) were independent predictors of tumor overgrowth. Twenty of the 22 patients were successfully treated by placement of a second dual stent, whereas the other two patients refused placement of a second stent or other further treatment. Overall, 19 of 20 patients (95%) showed improvement in symptoms after second stent placement. Duodenal perforation occurred in one of the 20 patients 125 days after placement of a second stent and was treated surgically. CONCLUSION Tumor overgrowth seems to be an uncommon complication of expandable metallic dual stent placement in patients with malignant gastroduodenal obstruction. Tumor overgrowth is associated with duodenal lesions, longer survival time, and shorter stricture length. Tumor overgrowth can be successfully managed by coaxial insertion of a second dual-expandable metallic stent into the obstructed first stent.

Fluoroscopically Guided Balloon Dilation of Benign Esophageal Strictures: Incidence of Esophageal Rupture and Its Management in 589 Patients

OBJECTIVE The purpose of this article is to investigate the incidence and management of esophageal rupture caused by balloon dilation in patients with benign esophageal strictures. MATERIALS AND METHODS Fluoroscopically guided esophageal balloon dilation was performed on 589 patients with benign esophageal strictures during an 18-year period. The strictures had a range of causes: postoperative anastomotic stricture, corrosive stricture, postradiation stricture, esophageal achalasia, esophageal reflux, congenital stricture, esophageal web, esophageal ulcer, medication fibrosis, chronic inflammation, and posttraumatic stricture (in descending order of frequency). Esophageal rupture was assigned to one of three categories: type 1 was intramural, type 2 was transmural with a contained leak, and type 3 was transmural with an uncontained mediastinal leakage. RESULTS A total of 1421 procedures were performed in 589 patients, with each patient undergoing 1-29 procedures. The technical success rate was 99.8%, and the clinical success rate was 91.7%. Patients with corrosive stricture underwent the highest number of procedures (mean, 4.38 procedures). The incidence of esophageal rupture was 14.7%. All esophageal ruptures were detected immediately after the procedure. Most ruptures (98.6%) were types 1 and 2 and were successfully managed conservatively. Only 1.4% of the ruptures were type 3 and required active management. One of the type 3 ruptures was successfully treated with a retrievable covered stent. Two patients with type 3 ruptures (0.96% of ruptures) underwent surgery and were successfully treated. The rupture rate was not statistically related to the diameter of balloon used. CONCLUSION The incidence of esophageal rupture after fluoroscopically guided esophageal balloon dilation was 14.7%. Almost all ruptures were type 1 or 2 and were successfully managed conservatively. Only 1.4% of the ruptures were type 3 and required active management. There was no procedure-related mortality in any patient. Therefore, in spite of the high incidence of ruptures, fluoroscopically guided balloon dilation is a safe procedure, particularly if a rupture is identified early and managed appropriately.

Fluoroscopically Guided Balloon Dilation for Pharyngoesophageal Stricture After Radiation Therapy in Patients With Head and Neck Cancer

OBJECTIVE The purpose of this article is to assess the safety and long-term efficacy of fluoroscopically guided balloon dilation for pharyngoesophageal strictures after radiation therapy in patients with head and neck cancers. MATERIALS AND METHODS From April 1997 to February 2009, fluoroscopically guided balloon dilation was performed in 17 patients with pharyngoesophageal strictures caused by radiation therapy. Technical success, clinical success (decrease of at least one grade in dysphagia score and good contrast passage on 1-month follow-up esophagogram), recurrence of dysphagia, and complications related to the procedure were retrospectively evaluated. RESULTS All 17 patients underwent 41 balloon dilation procedures, with each patient undergoing one to seven procedures (mean, 2.4 procedures). The technical success rate was 100%, and clinical success was achieved in 64.7% (11/17) of the patients. Five patients (29.4%) showed no recurrence of dysphagia after one session of balloon dilation. Of 12 patients (70.6%) with recurrence of dysphagia, 10 underwent repeat balloon dilation and two underwent gastrostomy after the first session of balloon dilation. The maximum balloon diameters were 15 mm (n = 22), 20 mm (n = 16), and 25 mm (n = 3). As minor complications, three cases of type 1 esophageal rupture occurred in two patients (11.8%). There were no major complications. CONCLUSION Although the recurrence rate was high with repeat balloon dilation, fluoroscopically guided balloon dilation seems to be a simple and safe primary treatment technique for pharyngoesophageal stricture due to radiation therapy in patients with head and neck cancer.