Kyung Tae Kim

Radiofrequency ablation of benign Thyroid nodules and recurrent Thyroid cancers: Consensus statement and recommendations

Thermal ablation using radiofrequency is a new, minimally invasive modality employed as an alternative to surgery in patients with benign thyroid nodules and recurrent thyroid cancers. The Task Force Committee of the Korean Society of Thyroid Radiology has developed recommendations for the optimal use of radiofrequency ablation for thyroid nodules. These recommendations are based on a comprehensive analysis of the current literature, the results of multicenter studies, and expert consensus.

Complications Encountered in the Treatment of Benign Thyroid Nodules with US-guided Radiofrequency Ablation: A Multicenter Study

PURPOSEnTo evaluate clinical aspects and imaging features of complications encountered in the treatment of benign thyroid nodules with radiofrequency (RF) ablation.nnnMATERIALS AND METHODSnInstitutional review board approval was obtained for this retrospective study, and informed consent was waived. From June 2002 to September 2009, 1459 patients underwent RF ablation of 1543 thyroid nodules with an RF system with internally cooled electrodes at 13 thyroid centers, which were members of Korean Society of Thyroid Radiology. Numbers and types of major and minor complications were assessed.nnnRESULTSnThe authors observed 48 complications (3.3%), 20 major and 28 minor. The major complications were voice changes (n = 15), brachial plexus injury (n = 1), tumor rupture (n = 3), and permanent hypothyroidism (n = 1). The minor complications were hematoma (n = 15), skin burn (n = 4), and vomiting (n = 9). All patients recovered spontaneously except for one with permanent hypothyroidism and one who underwent surgery.nnnCONCLUSIONnAlthough the complication rate of RF ablation is low, various complications may occur; comprehension of complications and suggested technical tips may prevent complications or properly manage those that occur.

Association Between Small Intestinal Bacterial Overgrowth and Peripheral Bacterial DNA in Cirrhotic Patients

BackgroundSmall intestinal bacterial overgrowth (SIBO) is regarded as the major risk factor of bacterial translocation. Few studies have investigated the direct relation between SIBO and translocation in cirrhotic patients. The purpose of this study is to examine the correlation between SIBO and bacterial DNA in the peripheral blood of patients with cirrhosis.AimsThe purpose of this study is to examine the correlation between SIBO and bacterial DNA in the peripheral blood of patients with cirrhosis.MethodsFifty-three cirrhosis cases and 42 controls underwent a lactulose breath test (LBT) every 15xa0min for 180xa0min. To detect and identify the presence of bacterial DNA fragments in peripheral blood, multiplex polymerase chain reaction (PCR) was performed.ResultsThe positive rate of LBT was significantly different between the two groups: 60.4% in the patient group and 28.6% in the controls. The SIBO positive rate was 81.3% in the cirrhosis patients with ascites, which was significantly higher than 51.4% in the cirrhosis patients with no ascites (Pxa0=xa00.03). Eight of the nine patients (88.9%) who had a history of one or more hepatic encephalopathy was SIBO-positive, which was higher than the patients who had had no hepatic encephalopathy. In the cirrhosis group, 32 patients (60.4%) were SIBO-positive, and ten of them (31.3%) were bacterial DNA-positive. Only one case (4.8%) was bacterial DNA-positive in the absence of SIBO-positive. In a multivariate analysis, only the existence of SIBO was the independent risk factor for bacterial DNA (Pxa0=xa00.026).Conclusions SIBO in cirrhosis patients was observed at a very high frequency, and SIBO showed a high correlation with bacterial translocation, suggesting that SIBO could be a major risk factor of bacterial translocation, especially in ascitic patients.

Aquaporin-2 urinary excretion in cirrhosis: relationship to vasopressin and nitric oxide.

The aquaporin (AQP) water channel plays an important role in the regulation of water. AQP2 is expressed in the collection duct of the kidney, serving as the final channel that helps to regulate water excretion in the kidneys and affecting the regulation of water and hyponatremia in cirrhotic patients. So far, research on aquaporin expression in cirrhosis has had various results. The purpose of this study is to investigate the factors that affect the regulation of expression of AQP in patients with cirrhosis. The study comprised 81 cirrhosis patients and 18 control subjects. In each group, 24-h urine was collected and nitric oxide and vasopressin levels were measured in the blood. The amount of urinary AQP was measured by Western blot. In this study, the positivity rate and amount of expression of AQP was higher in the cirrhotic group than that of the control group. AQP expression in urine was also compared between the groups with use of diuretics and the groups with no use of diuretics. A 57.4% positivity was observed with the former, whereas a 51.5% was seen in the latter. No significance was found between the groups (Pxa0=xa00.581). Expression of AQP in compensated cirrhotic patients is significantly higher than decompensated cirrhotic patients and is especially higher in cirrhotic patients with ascites than with no ascites. There is no relationship between the concentration of vasopressin and expression of AQP. Concentration of serum NOx is higher in cirrhotic patients than the control group and there is a positive association between the concentration of serum nitric oxide and AQP in urine. In conclusion, expression of AQP is increased in cirrhotic patients and is significantly higher in patients with ascites. There is a positive association between the expression of AQP and concentration of serum nitric oxide.

Dramatic increase in signal by integration of polymerase chain reaction and hybridization on surface of DNA microarray.

The cumbersome process required for diagnosis by DNA microarray can be simplified by simple extraction of nucleic acid from cells and by integration of liquid-phase polymerase chain reaction (PCR) and hybridization on the surface of a microarray slide. An unexpected benefit was the large (five- to sixfold) increase in detection signal that also is translated into an increase in sensitivity and the confidence level of diagnosis. The large increase in the detection signal appears to be due to participation of PCR primers as well as to extension of the immobilized capture probes during the hybridization process. The reason for the large increase in signal is not clear in view of only one round of DNA synthesis during the hybridization step. The integrated process correctly identified various genotypes of human papillomavirus (HPV) in the infected clinical human cervical specimens with specificity and efficiency. The process described in this article saves labor, time, and cost and should be applicable for automation of diagnosis by DNA microarray.

Dramatic increase in the signal and sensitivity of detection via self-assembly of branched DNA.

In molecular testing using PCR, the target DNA is amplified via PCR and the sequence of interest is investigated via hybridization with short oligonucleotide capture probes that are either in a solution or immobilized on solid supports such as beads or glass slides. In this report, we report the discovery of assembly of DNA complex(es) between a capture probe and multiple strands of the PCR product. The DNA complex most likely has branched structure. The assembly of branched DNA was facilitated by the product of asymmetric PCR. The amount of branched DNA assembled was increased five fold when the asymmetric PCR product was denatured and hybridized with a capture probe all in the same PCR reaction mixture. The major branched DNA species appeared to contain three reverse strands (the strand complementary to the capture probe) and two forward strands. The DNA was sensitive to S1 nuclease suggesting that it had single-stranded gaps. Branched DNA also appeared to be assembled with the capture probes immobilized on the surface of solid support when the product of asymmetric PCR was hybridized. Assembly of the branched DNA was also increased when hybridization was performed in complete PCR reaction mixture suggesting the requirement of DNA synthesis. Integration of asymmetric PCR, heat denaturation and hybridization in the same PCR reaction mixture with the capture probes immobilized on the surface of solid support achieved dramatic increase in the signal and sensitivity of detection of DNA. Such a system should be advantageously applied for development of automated process for detection of DNA.

The Role of Nitric Oxide in the Expression of Renal Aquaporin 2 in a Cirrhotic Rat Model: Does an AVP-Independent Mechanism Exist for the Regulation of AQP2 Expression?

The aquaporin (AQP) water channel is expected to play a decisive role of hyponatremia and water retention in cirrhotic patients. Despite the importance of the water channel, however, previous findings vary widely when it concerns AQP2 of the kidneys in subjects with cirrhosis. The purpose of this study was to investigate the expression of AQP2 in the distal renal tubule in cirrhosis, and the presence of the nitric oxide-AQP2 signaling pathway as a possible vasopressin-aquaporin-independent pathway. Sixty male Wister rats were assigned to six groups: (1) control; (2) TAA (thioacetamide); (3) TAA with nitric oxide donor; (4) TAA with nitric oxide inhibitor; (5) TAA with HMG CoA reductase inhibitor; (6) TAA with tetrahydrobiopterin. Immunohistochemical staining for AQP2, real-time polymerase chain reaction (PCR) for AQP2 and 3, citrulline assay, and renal cGMP concentration were measured. The AQP2-positivity of cirrhotic rats were higher than the controls (Pxa0<xa00.05). The AQP2-positivity decreased in the nitric oxide donor group, but the proportion rose back up when the subjects were injected with the nitric oxide inhibitor (Pxa0<xa00.05). The expression of AQP2 and AQP3 mRNA was also found to show an increase in the cirrhotic group as compared with the normal controls (Pxa0<xa00.05). The cirrhotic group administered with nitric oxide donor showed a significant decline in the expression of the mRNA. The control group’s cGMP concentration was lower than that of the cirrhotic group (Pxa0<xa00.05), but a comparison of the two groups injected with nitric oxide modulators, such as statin and BH4, did not show significant differences in the cGMP concentration level. The expression of AQP2 of the kidneys increased in the cirrhotic rats. AQP2 had relations to the activity changes of nitric oxide synthetase.

Effects of natural resistance-associated macrophage protein 1 and toll-like receptor 2 gene polymorphisms on post-weaning piglet survivability

Predicting resistance or susceptibility to infectious diseases on the basis of the genotypes of animals regarding disease or immune related genes could be important in animal production. We evaluated the potential influence of the genetic polymorphisms of four immune related genes, porcine beta defensin 4, interferon-induced GTP-binding protein Mx1, natural resistance-associated macrophage protein 1 (Nramp1), and Toll-like receptor 2 (TLR2) on post-weaning piglet survivability in farms. We selected a single SNP that satisfied the criteria of non-synonymous substitutions and the minor allele frequency >0.1 from each gene, and performed PCR–RFLP. Distributions of allele and genotype frequencies of the SNPs were, in general, significantly different among the five breeds (Berkshire, Yorkshire, Duroc, Landrace, and Korean native pigs. Initially, 371 randomly collected Yorkshirexa0×xa0Landrace F1 piglets consisting of post-weaning survival (nxa0=xa0185) and non-survival groups (nxa0=xa0186) were genotyped for the selected SNPs. For the Nramp1 and TLR2 SNPs, genotype frequencies were significantly different between the two groups (Pxa0<xa00.05). To confirm the results, additional animals that were collected in a different time-period were genotyped for the Nramp1 (nxa0=xa0390) and TLR2 (nxa0=xa0240) SNPs. The results using the combined samples (nxa0=xa0761) were consistent with the initial analysis (Pxa0<xa00.01), suggesting that the genetic polymorphisms of Nramp1 and TLR2 affect post-weaning piglet survivability. The relative risks, i.e. odds ratios, between the beneficial and non-beneficial genotypes to piglet survivability were 4.88 and 29.65 for the Nramp1 and TLR2 SNPs, respectively.

Alpha (1,2)-Fucosyltransferase M307A Polymorphism Improves Piglet Survival

To confirm the beneficial effects of alpha (1,2)-fucosyltransferase (FUT1) M307 A on piglet survival on commercial farms, we performed PCR-RFLP analysis of FUT1 M307 in successfully marketed (n = 245) and disease affected/deceased pigs during weaning (n = 252) at a commercial farm. We also evaluated the FUT1 genotypes of 190 healthy pigs from three different genetic backgrounds. The distribution of genotypes differed between the successfully marketed and disease affected/deceased pig groups. The frequency of the A allele, associated with resistance to edema and post-weaning diarrhea, was higher in the post-weaning survival group (0.21) than in the non-survival group (0.16, P < 0.05). The odds ratio for piglet survival between AA and GG genotypes was 1.98; thus, piglet survival for individuals with the AA genotype was almost two-fold greater than for GG individuals. The FUT1 gene polymorphism can be used as an effective marker for selection programs to improve post-weaning piglet survival.

A Study on the Design Supporting System for Cylinder Using Pro/PROGRAM

Though the cylinder shape is similar, the shape of the cylinder changes from model to model. Therefore the time consuming procedure of forming cylinder should be repeated for every type of cylinders. Consequently, a new design system is highly demanded to reduce those undesirable time. In this study a 3-D cylinder design supporting system has been developed using Pro/PROGRAM of the widespread CAD software Pro/ENGINEER. With the input geometric data of piston, tube, cover, this 3-D design supporting system could complete the basic design process. This new design system showed remarkable design efficiency also when it was applied to the case of redesign and modification of the previous standard output for a different cylinder type.