Biomedical subjects

Yong-Jin Kim

Publications and source records attributed to Yong-Jin Kim.

15 recordsLinked to original sources

PubMed2004

Influence of coexisting surface-active agents on leachability of dioxins in raw and treated fly ash from an MSW incinerator.

The leaching behavior of dioxins from raw and treated fly ash (FA) under the coexistence of several types of surface-active agents (SAAs) was examined by batch leaching tests to obtain significant information not only for evaluating leachability of dioxins as hydrophobic organic pollutants (HOPs) under the severe environment in which SAAs coexist, but also for evaluating the reduction efficiency of dioxin-leachability from the treated FA. Enhancement of dioxin-leachability by sufficient addition of SAAs was observed in the leaching test, whereas addition of a smaller quantity depressed the leachability. The higher the degree of chlorination in PCDDs/PCDFs homologues, the more effectively the SAAs enhanced the leachability. Moreover, there was a large difference in the potential for leachability enhancement due to each surface activity, based on critical micelle concentration (CMC) of the SAAs although Aldrich humic acid enhanced the leachability at a much lower concentration than CMC. A comparison of the leachability in FA treated by several methods showed a difference in the reduction efficiency of leachability, depending on the adsorption of SAAs by each treated FA.

Carbon↗

PubMed2003

Interferon regulatory factor-1 (IRF-1) is a mediator for interferon-gamma induced attenuation of telomerase activity and human telomerase reverse transcriptase (hTERT) expression.

Constitutive activation of the telomerase is a key step in the development of human cancers. Interferon-gamma (IFN-gamma) signaling induces growth arrest in many tumors through multiple regulatory mechanisms. In this study, we show that IFN-gamma signaling represses telomerase activity and human telomerase reverse transcriptase (hTERT) transcription, and suggest that this signaling is mediated by IRF-1. Ectopic expression of IRF-1 attenuated hTERT promoter activity. Murine embryonic fibroblasts (MEFs) genetically deficient in IRF-1 (IRF-1(-/-)) showed an elevated level (>15 times) of hTERT promoter activity as compared to the hTERT promoter activity of wild-type MEFs. The telomerase activity and hTERT expression in IRF-1(-/-) MEFs were downregulated by IRF-1 transfection. Interestingly, less extent of telomerase repression was observed in HPV E6 and E7 negative, p53 mutant HT-3 cells than in HPV 18 E6 and E7 positive HeLa cells (intact p53). These findings provide evidence that IRF-1 is a potential mediator of IFN-gamma-induced attenuation of telomerase activity and hTERT expression.

Animals↗

PubMed2003

False-positive exercise echocardiograms: impact of sex and blood pressure response.

BACKGROUND: Factors related to false-positive results of exercise echocardiography (ExE) to diagnose coronary disease have not been extensively studied. In addition, previous studies were performed before routine use of digital and tissue harmonic imaging. We evaluated the clinical and echocardiographic predictors of false-positive results during ExE. METHODS: Four hundred sixty-four patients who had both coronary angiography and ExE were enrolled retrospectively. Significant coronary disease was defined by stenoses > or =50% lumen diameter. RESULTS: Fifty-eight (13%) had false-positive results. Thirty-one (53%) of these patients were women, which was significantly higher than the percentage of women (25%) in the true-positive group (P <.001). Average peak systolic blood pressure (BP) in the false-positive group was significantly higher than in the true-positive group. Test specificity was decreased at higher levels of BP without change of sensitivity. Men demonstrated a decrease in specificity at peak systolic BP > or =200 mm Hg, whereas women showed a sharp decrease in specificity at BP > or =180 mm Hg. Wall motion score index (WMSI) after peak exercise and the proportion of high- and intermediate-risk patients according to Duke score were significantly lower in the false-positive than in the true-positive group. CONCLUSIONS: The factors predictive of false-positive results during ExE to diagnose coronary disease were female sex, higher BP at peak exercise, lower risk by Duke score and lower number of abnormal segments and wall motion score index after peak exercise. Women appear to be susceptible to wall motion abnormalities caused by elevated exercise BP. These variables should be considered in the interpretation of ExE.

Adult↗

PubMed2003

Leaching characteristics of polycyclic aromatic hydrocarbons (PAHs) from spiked sandy soil.

In order to evaluate the factors affecting leachability of hydrophobic organic pollutants (HOPs), we performed leaching tests under a variety of conditions using sandy soil contaminated with phenanthrene and pyrene. The results obtained were: (1) the shaking time, temperature, and dissolved humic matter (DHM, as coexisting matter) increased leachability; (2) ionic strength reduced leachability; and (3) the liquid-to-solid ratio and pH level had no effect on leaching concentration of HOPs. In DHM-added leaching tests assuming equilibrium with HOPs, DHM, and solid matrix, the partitioning (binding) coefficient of HOPs to DHM was accurately calculated with the equations proposed in this study. While we recommend taking into consideration the coexistence of DHM, it is difficult to use universally because its properties differ according to origin and extracting method. It is therefore reasonable to use an alternative reagent having an effect similar to that of DHM.

Adsorption↗

PubMed2003

Sinus node dysfunction after Fontan modifications--influence of surgical method.

BACKGROUND: Sinus node dysfunction (SND) is reported to be a troublesome complication following various types of Fontan operations. The correlation of post-Fontan SND with surgical methods was evaluated in this study. METHODS: By reviewing the medical records, surface ECGs, and Holter monitoring, the range of heart rate (HR) and the risk of SND at intermediate term after Fontan type operation (follow up: 41.3+/-13.1 months) were analyzed between two age matched groups of patients, consisting of the extracardiac conduit group (EC, n=33) and the lateral tunneling group (LT, n=35). RESULTS: Junctional rhythm was observed in nine out of 35 patients in LT and five out of 33 patients in EC during the follow-up period. Resting HR was faster in EC than that in LT (108+/-15 vs. 82+/-21, P<0.001). Average and maximal HR in Holter monitoring were also faster in EC than those in LT. SND was found in 13 cases (10 in LT, three in EC) during follow-up and one required pacemaker implantation. In the case of situs solitus heart, SND was less frequent in EC than in LT (0/16 vs. 8/26, P=0.01). In the case of heterotaxy syndrome, SND occurred in similar number of cases (3/17 vs. 2/9). The staged approach to Fontan completion did not influence SND. LT repair was the only factor causing sinus node dysfunction according to multivariate logistic regression (P=0.03, OR 5.96). CONCLUSIONS: Lateral tunnel type surgical repair was more likely to lead to the development of sinus node dysfunction than extracardiac conduit operation. In the case of heterotaxy syndrome, surgical method had no significant influence.

Cardiac Surgical Procedures↗

PubMed2003

Determinants of exercise capacity in hypertensive patients: new insights from tissue Doppler echocardiography.

BACKGROUND: Determinants of exercise capacity have not been clearly defined in hypertensive patients. Doppler tissue imaging (DTI), a recently developed echocardiographic modality, is useful for evaluating left ventricular (LV) function regardless of loading conditions. The present study was performed to identify the determinants of exercise capacity in hypertensive patients using DTI. METHODS: We studied 48 hypertensive patients (26 men; mean age, 57 +/- 9 years) with normal LV ejection fraction (>50%). Conventional echocardiographic indexes were measured before and after symptom-limited treadmill exercise. Also, longitudinal systolic (S(L)') and diastolic myocardial velocities (E(L)' and A(L)') and radial velocities (S(R)', E(R)', A(R)') were measured using DTI with the sample volume at the LV basal posterior wall. RESULTS: Mean exercise time was 525 +/- 135 sec. Mean LV ejection fraction was 61% +/- 6%. Mean LV mass index was 110.9 +/- 24.4 g/m(2). On univariate analysis, S(L)', E(L)', A(L)' and percentage increase of S(R)' velocity after exercise showed significant correlation with exercise time. However, only E(L)' and percentage increase of S(R)' remained significant after multivariate analysis. CONCLUSIONS: Left ventricular contractile reserve and relaxation property are important cardiac factors determining exercise capacity. Early diastolic longitudinal myocardial velocity might be useful for identifying hypertensive patients with poor exercise capacity.

Adult↗

PubMed2003

Mechanism and incidence of notched pulmonary venous atrial reversal wave.

In certain patients, pulmonary venous flow pattern obtained by the pulsed wave Doppler during transesophageal echocardiography shows a notching on the atrial reversal (A) wave. However, the incidence or the mechanism of this notched A wave has not been described. After transthoracic echocardiographic evaluation for the chamber sizes, wall thickness, and left-ventricular function, transesophageal echocardiography was performed in 100 patients with in sinus rhythm. Discernible pulmonary venous A wave was observed in 46 patients. Among these 46 patients, notched A wave was observed in 11 (31%). In 4 patients with notched A wave, left-atrial pressure waveforms could be obtained during mitral balloon valvuloplasty. In all these patients, left-atrial pressure waveforms showed prominent c waves. In 2 patients, transesophageal echocardiography was repeated after mitral balloon valvuloplasty. Late peak of the notched A wave decreased with the decrease in the magnitude of rise in left-atrial c wave. Among the transthoracic echocardiographic parameters, patients with notching (n = 11) had significantly larger left atriums than patients without notching (n = 35)(49.3 +/- 6.2 vs 37.3 +/- 4.4 mm, P <.0001). There were no significant differences in left-ventricular dimensions, wall thickness, and ejection fraction. In conclusion, notched pulmonary venous A wave indicates the presence of left-atrial c wave; and presence of left-atrial c wave may represent decreased left-atrial compliance.

Adult↗

PubMed2003

Prediction of postoperative left ventricular systolic function with Doppler-derived dP/dt in patients with chronic aortic regurgitation.

To evaluate the value of Doppler-derived dP/dt as a predictor of postoperative left ventricular (LV) systolic function in patients with chronic aortic regurgitation, we evaluated 29 patients who underwent aortic valve replacement (n = 17) or valve repair. Doppler-derived dP/dt was determined from the continuous wave Doppler signal of the aortic regurgitation jet preoperatively. Preoperative LV ejection fraction (LVEF) and Doppler-derived dP/dt were 48 +/- 11% and 701 +/- 204 mm Hg/s, respectively. LVEF decreased to 43 +/- 12% at immediate postoperative period and improved to 54 +/- 11% at late postoperative period. In multivariate analysis, only dP/dt was an independent predictor of late postoperative LVEF (r = 0.59, P =.006). A dP/dt <or=700 mm Hg/s was the best predictor of late postoperative systolic dysfunction (LVEF <50%) with a sensitivity of 94% and a specificity of 75%. Doppler-derived dP/dt may be useful to predict postoperative LV systolic function.

Adult↗

PubMed2003

Pirfenidone suppressed the development of glomerulosclerosis in the FGS/Kist mouse.

Pirfenidone (PFD) is a newly developed anti-fibrotic agent. We evaluated the effect of PFD for the prevention of renal fibrosis using a spontaneous progressive glomerulosclerosis animal model, FGS/Kist mice. Male and female FGS/Kist mice were fed a diet containing 0.5% PFD or the same control diet (CD) without PFD, for 1, 2, or 3-month periods. Body weight was monitored for the general effect of PFD on the mice. Proteinuria and glomerular filtration rate (GFR) were evaluated for renal function. The sclerosis index was examined for the morphological changes. There were no significant changes in body weight between the PFD and control groups in both sexes. Proteinuria levels were low in all the PFD groups compared to the corresponding CD groups. The sclerosis scores were also reduced in both sexes of the 3-month PFD groups (p<0.05), and glomerular filtration rates were increased in both sexes of the 3-month PFD groups compared to the CD groups. The treatment of PFD for 1 or 2-month periods did not have statistic significances but the treatment for 3 months had statistic significances in sclerosis and GFR compared to CD groups. These results suggested that long-term administration of PFD suppressed the progression of glomerulosclerosis and improved renal function of the FGS/Kist mice.

Animals↗

PubMed2002

Absence of postprandial surge in coronary blood flow distal to significant stenosis: a possible mechanism of postprandial angina.

OBJECTIVES: This study was designed to investigate a possible mechanism of postprandial angina. BACKGROUND: Postprandial angina has been recognized for more than two centuries; however, its mechanism is still controversial. The most widely accepted mechanism involves increased myocardial oxygen demand after food intake. Recently, the redistribution in coronary blood flow (CBF) was suggested as a possible mechanism. METHODS: Twenty young, healthy volunteer controls and 20 patients with significant stenosis in the left anterior descending (LAD) or left main coronary artery were enrolled in the study. Coronary blood flow was evaluated in the distal LAD by using transthoracic Doppler echocardiography before and 15, 30, 45, and 60 min after food intake. In the CBF curve, the time velocity integral of diastolic flow (Dtvi) and the product of Dtvi and heart rate (HR) were measured. In six patients, these measurements were repeated after successful coronary intervention. RESULTS: In the healthy volunteer controls, Dtvi and Dtvi x HR increased after food intake with a peak value at 15 min, which indicates the presence of postprandial surge in the CBF. Fasting values and peak values at 15 min were significantly different (Dtvi: 15.1 +/- 4.9 cm/s vs. 18.9 +/- 5.9 cm/s, p = 0.04, Dtvi x HR: 862.2 +/- 261.5 cm/min vs. 1,174.2 +/- 307.5, p = 0.002). In contrast with the controls, despite postprandial increase in double product (HR x blood pressure), Dtvi and Dtvi x HR in the patient group decreased after food intake, with a nadir value at 45 min. Fasting values and nadir values at 45 min were significantly different (Dtvi: 24.0 +/- 19.6 cm/s vs. 19.3 +/- 17.1 cm/s, p < 0.001, Dtvi x HR: 1,449.6 +/- 1,044.0 cm/min vs. 1,273.4 +/- 1,000.9 cm/min, p = 0.002). In six patients, the CBF pattern resumed the normal pattern of postprandial surge in the CBF after successful coronary intervention. CONCLUSIONS: Results of our study suggest that "steal phenomenon" may play a role in the mechanism of postprandial angina.

Adult↗

PubMed2002

Effect of dissolved humic matters on the leachability of PCDD/F from fly ash--laboratory experiment using Aldrich humic acid.

The effect of dissolved humic matters (DHM) on the leachability of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) in fly ash was studied theoretically and in laboratorial condition to verify the previous results for pilot and field experiment of incineration residues landfill. In theoretical review, it was shown that DHM could influence the actual solubility and leachability of PCDD/F. The higher concentration of DHM showed the higher leachability of PCDD/F. In the leaching test, three different DHM concentrations and pHs of solutions were adopted to fly ash samples imaging the various characteristics of municipal solid waste leachate. It was proved experimentally that the leachability of PCDD/F increased with increasing DHM concentration in all pH conditions. The highest leachability was shown at the highest pH. Isomer distribution patterns of PCDD/F in all leachates were similar in all pH conditions. It backed up the distribution theory of PCDD/F between DHM and water.

Benzofurans↗

PubMed2002

A pilot and field investigation on mobility of PCDDs/PCDFs in landfill site with municipal solid waste incineration residue.

A field investigation by boring was carried out in a landfill site primarily with municipal solid waste incineration residue. From the collected core samples, vertical profiles of homologous content of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs) in the landfill layer were traced and the behavior of PCDDs/PCDFs was examined. In addition, a pilot-scale study was conducted on the PCDDs/PCDFs leached from incineration fly ash and the treated one using large landfill simulation columns (lysimeters) and the leaching behavior of PCDDs/PCDFs was examined. As a result, it was found that the coexistence of dissolved coloring constituents (DCCs), which might be composed of constituents like dissolved humic matters having strong affinity for hydrophobic organic pollutants, could enhance the leachability of PCDDs/PCDFs, thus contributing to the vertical movement and leaching behavior of PCDDs/PCDFs in the landfill layers of the incineration residue. Moreover, it is highly probable that DCCs derive from the unburned carbon in the bottom ash mixed and buried with the fly ash containing a high content of PCDDs/PCDFs.

Benzofurans↗

PubMed2002

A case of chronic renal allograft failure by effects of elderly donor.

We experienced a case of chronic renal allograft failure from an elderly donor. A 23-year-old man received living-related transplantation in 1998. The donor was his father, 66 years old and 69 kg body weight. The recipient was 88 kg and the cause of the renal failure was IgA nephropathy. The graft function decreased 2 months after transplantation. One year later, proteinuria and haematuria developed. Six months later, when the creatinine rose to 2.5 mg/dL, a renal transplant biopsy was performed. Characteristic microscopic features were: diffuse segmental to global glomerulosclerosis, hypertrophy of non-sclerotic glomerulus, tubular atrophy, arteriolar hyalinosis, interstitial lymphocytic infiltration with tubulitis and anti-IgA deposition on glomeruli. The pathological diagnoses were recurrent IgA nephropathy, acute rejection and chronic cyclosporin nephrotoxicity. Diffuse glomerulosclerosis as well as glomerular hypertrophy might be the end result of hyperfiltration, which was a consequence of a small number of functioning nephrons. The old age of the donor and the heavy body weight of the recipient could be risk factors for this case.

Adult↗

PubMed2002

A case of second branchial cleft cyst with oropharyngeal presentation.

Second branchial cleft cysts are the most common type of branchial abnormalities and usually found high in the neck. Oropharyngeal presence of branchial cleft cyst is very rare. We report a case of oropharyngeal branchial cleft cyst in 2-yr-old girl with about 1 x 1 cm sized cystic mass, which had not any specific symptom. It was removed completely under impression of mucocele and did not have tract-like structure. However, cyst had a squamous epithelium-lined wall with lymphoid aggregation in histopathologic study, which was characteristic finding of branchial cleft cyst. Patient discharged without any complication and there was no evidence of recurrence for 18 months follow-up. We review reported oropharyngeal or nasopharyngeal presentation of these cases in English literature and embryological explanation.

Branchioma↗

PubMed2002

Effects of thyroxine on hyperkalemia and renal cortical Na+, K+ - ATPase activity induced by cyclosporin A.

Cyclosporin A (CsA)-induced hyperkalemia is caused by alterations in transepithelial K+ secretion resulting from the inhibition of renal tubular Na+, K+ -ATPase activity. Thyroxine enhances renal cortical Na+, K+ -ATPase activity. This study investigated the effect of thyroxine on CsA-induced hyperkalemia. Sprague-Dawley rats were treated with either CsA, thyroxine, CsA and thyroxine, or olive-oil vehicle. CsA resulted in an increase in BUN and serum K+, along with a decrease in creatinine clearance, fractional excretion of potassium, and renal cortical Na+, K+ -ATPase activity, as compared with oil vehicle administration. Histochemical study showed reduced Na+, K+ -ATPase activity in the proximal tubular epithelial cells of the CsA-treated compared with the oil-treated rats. Histologically, isometric intracytoplasmic vacuolation, disruption of the arrangement and swelling of the mitochondria, and a large number of lysosomes in the tubular epithelium were characteristic of the CsA-treated rats. Co-administration of thyroxine prevented CsA-induced hyperkalemia and reduced creatinine clearance, Na+, K+ -ATPase activity, and severity of the histologic changes in the renal tubular cells when compared with the CsA-treated rats. Thyroxine increased the fractional excretion of potassium via the preservation of Na+, K+ -ATPase activity in the renal tubular cells. Thus, the beneficial effects of thyroxine may be suited to treatment modalities for CsA-induced hyperkalemia.

Animals↗