• Journal of the Mineralogical Society of Korea
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• v.20 no.3
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• pp.193-201
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• 2007

We used $^6Li$ and $^7Li$ MAS NMR to investigate the fate and local environments of Li in the interlayer of clay minerals such as hectorite, Woming-montmorillonite, beidellite, and lepidollite at room and high ($250^{\circ}C$) temperature. Although $^6Li$ NMR spectra show narrower peaks than those of $^7Li$ NMR, S/N ratio is low and there are no obvious differences in chemical shifts suggesting that it is difficult to apply $^6Li$ NMR to have information on the local environments of Li in the clay interlayers. $^7Li$ NMR spectra, however, show changes in the peak width and quadrupole patterns providing information on the local environments of Li in the interlayer even though changes in the chemical shift are not observed. In montmorillonite, two different local environments of Li are observed; one has a narrow peak with typical quadrupole patterns whereas another has a broad peak without those of the patterns. Changes in the peak width is also observed from broad to narrow in the $^7Li$ NMR spectra for beidellite but not for hectorite at high temperature. Our results suggest that the peak width change in the broad peak is attributed to the coordination changes in the water molecules around Li which is tightly bonded on the basal oxygen of Si tetrahedra as inner-sphere complexes. The narrow peak in montmorillnoite can be assigned to the Li bended as outer-sphere complexes.

• Childhood Kidney Diseases
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• v.1 no.1
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• pp.38-45
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• 1997

Purpose : Vesicoureteral reflux(VUR) in childhood may be the primary cause of recurrent urinary tract infection and renal scarring. Renal ultrasonography, DMSA, and voiding cystourethrogram are the standard clinical methods for detection of vesicoureteral reflux. But these methods have many disadvantages such as invasiveness and high cost. So, we studied to observe the significance of urine ${\beta}_2$-microglobulin in association with other non-radiologic methods for predictng vesicoureteral reflux. Methods : We evaluated 40 patients with urinary tract infection who were admitted to Korea university Hospital from July 1993 to June 1994. Among them, 24 patients revealed urinary tract infection and vesicoureteral reflux(group A), 16 patients revealed only urinary tract infection(group B). Both groups were compared by presence of fever, hematuria, and proteinuria, positivity of CRP, and level of BUN, Cr, GFR by 99mTc-DTPA, urine ${\beta}_2$-microglobulin, 24 hours urine albumin. Results : 1) Among 24 patients who had vesicoureteral reflux, 14 had unilateral VUR, 10 had bilateral VUR, three kidneys with grade I, nine with grade II, eleven with grade III, eleven with grade IV by classification of International Reflux Study Committee. Among them, 14 patients had renal scar, five with type A, five with type B, four with type C, none with type D by Smellie's classification. 2) The mean of GFR, BUN, Cr, 24hrs urine albumin and the presence of hematuria and proteinuria showed no significant difference between group A and group B. The mean of urine ${\beta}_2$ microglobulin in group A and group B were $283.6{\pm}195.8{\mu}g/l$ and $78.7{\pm}48.5{\mu}g/l$ respectively, showing that group A had a higher value than group B (p<0.01). In case of ${\beta}_2$ microglobulin > $120{\mu}g/l$ and CRP(+), the sensitivity was 93.3% and the specificity is 77.8% for detecting of VUR. In case of ${\beta}_2$-microglobulin>$120{\mu}g/l$ and fever(+), the sensitivity was 92.2%, and the specificity was 62.5% for detecting of VUR Conclusions : If the level of urinary ${\beta}_2$-microglobulin is more than 120ug/l in children with urinary tract infection in association with fever(+) or CRP(+), it can predict VUR. So we can use it for early detection of VUR.

• Childhood Kidney Diseases
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• v.2 no.2
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• pp.138-144
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• 1998

Purpose : The use of cyclosporine and mitomycin in various immunologic or neoplastic disorders has been known to cause wide-ranged nephrotoxic effects including thrombotic microangiopathy. However, the mechanism of nephrotoxicity of these drugs has not been studied adequately, so that present experimental study has been undertaken to find out whether these drugs can cause direct damage to the kidney and to clarify the pathogenetic mechanism of nephrotoxic effect of these drugs. Materials and methods : Sprague-Dawley rats weighing 250-300 gm were used for experimental animals and unilateral renal perfusion technique, modified from the method described by Hoyer et al was used. Isolation of left kidney from systemic circulation was made by clamping aorta and left renal vein and a hole was punctured in the anterior wall of the left renal vein. Cyclosporine (2.5 mg in 4 ml solution) and mitomycin (1.6 mg in 4ml solution) were infused through left renal artery and normal saline was used in control rats. Forty-eight hours after infusion of the drugs, animals were sacrificed and left kidney removed and processed for histologic examination. Total ischemic time of left kidney was less than 15 minutes: Results : Cyclosporine-perfused group showed severe swelling of glomerular endothelial ceil along with swelling of glomerular epithelial cell and interstitial vascular endothelial cell. Mitomycin-perfused group also showed severe swelling of glomerular endothelial and epithelial cells. And in addition to these findings, they demonstrated platelets aggregation, swelling and degranulation of platelets and fibrin accumulation in some of the capillaries, indicating occurrance of thrombotic microangiopathy. Conclusion : present experiment indicates that cyclosporine and mitomycin can cause direct toxic injury to renal endothelial cell. And this direct toxic damage to endothelial cell seems to be an important initiating event for the development of thrombotic microangiopathy.

• Clinical and Experimental Pediatrics
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• v.46 no.10
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• pp.977-982
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• 2003

Purpose : This study aimed to examine the excretion of various urinary proteins in children with a history of urinary tract infection(UTI), with or without vesicoureteral reflux(VUR) or reflux nephropathy, and to identify means of predicting the severity of VUR or the presence of reflux nephropathy as indicated by these markers, and to know how these markers are changed after resolution of VUR. Methods : We studied 30 children with previous UTI, without VUR and renal scarring(group I), 12 children with VUR, without evidence of renal scarring(group II), and 34 children with VUR and renal scarring(group III). 24-hour or 12-hour urine ${\beta}_2$ microglobulin(${\beta}_2$ MG), microalbumin and N-acetyl-${\beta}$-D-glucosaminidase(NAG) were measured in each child. Urinary protein excretions were analyzed according to the degree of VUR(mild VUR : a grade reflux I-III, severe VUR : a grade reflux IV-V). Cases of bilateral VUR were graded by the higher grade of reflux detected. A total of 46 children with primary VUR were followed. Among these patients, VUR was completely resolved in 16 children. Voiding cystourethrography(VCUG) and DMSA scan were performed every year. Values for urinary markers were estimated every year. Results : 24 or 12 hour urine microalbumin and NAG excretions were significantly increased in group III compared to group I(microalbumin : $27.7{\pm}26.0mg/gCr$ vs $15.0{\pm}10.7mg/gCr$, P<0.05, NAG : $15.2{\pm}18.7U/gCr$ vs $3.4{\pm}2.2U/gCr$, P<0.05). Urinary ${\beta}_2$ MG excretions were not significantly different between groups. Urinary NAG excretions were elevated in the group of children with severe VUR compared to mild VUR($26.8{\pm}27.1U/gCr$ vs $7.6{\pm}3.8U/gCr$, P<0.05). After resolution of VUR, urinary microalbumin and NAG excretions were decreased(P<0.05). Conclusion : Urinary microalbumin and NAG may be useful clinical indicators to predict the presence of reflux nephropathy and the resolution of VUR. Especially, urinary NAG excretions may be used as a possible method to predict the severity of VUR.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.5
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• pp.492-501
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• 2007

Coastal disasters have become one of the most important issues in every coastal country. In Korea, coastal disasters such as storm surge, sea level rise and extreme weather have placed many coastal regions in danger of being exposed or damaged during subsequent storms and gradual shoreline retreat. A storm surge is an onshore gush of water associated with a tow pressure weather system, typically in typhoon season. However, it is very difficult to predict storm surge height and inundation due to the irregularity of the course and intensity of a typhoon. To provide a new scheme of typhoon damage prediction model, the scenario which changes the central pressure, the maximum wind radius, the track and the proceeding speed by corresponding previous typhoon database, was composed. The virtual typhoon scenario database was constructed with individual scenario simulation and evaluation, in which it extracted the result from the scenario database of information of the hereafter typhoon and information due to climate change. This virtual typhoon scenario database will apply damage prediction information about a typhoon. This study performed construction and analysis of the simulation system with the storm surge/coastal inundation model at Masan coastal areas, and applied method for predicting using the scenario of the storm surge.

• Childhood Kidney Diseases
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• v.7 no.1
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• pp.52-59
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• 2003

Purpose : The renin-angiotensin system(RAS) plays an important role in renal growth and development. We have studied the prevalence of renal anomalies and documented the association between karyotype and renal anomalies using IVP and ultrasonography. Furthermore, to investigate the impact of RAS gene polymorphism on renal anomaly in Turner syndrome, we examined the ACE I/D genotype, angiotensinogen(AGT) gene M235T, angiotensin receptor type 1(ATR) gene A1166C. Methods : Cytogenetic analysis was performed in 33 Turner syndrome patients on peripheral blood lymphocytes. Ultrasonography(US) of the kidneys and collecting system and intravenous pyelography(IVP) were perfomed in all patients. Nuclear scintigraphy{Tc 99m dimercaptosuccinic acid(DMSA) scan} was also performed for the definite renal diagnosis if indicated. And, ACE I/D genotype, angiotensinogen(AGT) gene M235T, angiotensin receptor type 1(ATR) gene A1166C were examined by PCR amplification of genomic DNA samples. Results : The prevalence of renal anolmalies in Turner syndrome was 36.4%(12/33). The Karyotype 45, X was observed in 18 of the 33 girls(54.5%), of whom 8(44.4%) had renal anomalies. Mosaic karyotypes were observed in 11(33.3%) and four(12.2%) had a non-mosaic structural aberration of the X chromosome. In this group 4(25.7%) had renal anomalies. More renal anomalies were associated with the 45, X karyotype than those with mosaic/structural abnormalities of X chromosome, but the difference was not statistically significant(P>0.05). And, there was no significant differences in the RAS gene polymorphism and allele frequencies between renal anomaly group and normal group in Turner syndrome. Conclusion : The prevalence of renal anolmalies in Turner syndrome was 36.4%. There is no significant differences in the RAS gene polymorphism and allele frequencies between the renal anomaly group and the normal group in Turner syndrome.

• Childhood Kidney Diseases
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• v.14 no.2
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• pp.203-209
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• 2010

Purpose : It has been a common medical practice to use prophylactic antibiotics to prevent recurrent urinary tract infections (UTI) in high risk situations such as urinary tract obstruction, vesicoureteral reflux, neurogenic bladder, or urinary stones. But sometimes, we meet difficult situation of breakthrough infections (BI) which might cause new or progressive renal scarring. The clinical characteristics of children contracting breakthrough UTI experienced in a single center were studied. Methods : The study was done retrospectively through medical records of 150 pediatric patients who had been cared in pediatric and urologic clinics of Pusan National University Hospital from Jan. 2001 till June 2006 and had prophylactic antibiotics to prevent recurrent UTI. Results : The starting age of prophylactic antibiotics of 150 patient was 1-76 months, and median age was 5 months. The BI developed 61 times in 43 patients (28.7%), 1.5 times per 100 patient-months. The BI occurred more frequently in patients with higher grade of VUR, and in the cases with abnormal DMSA scan. Co-trimoxazole was more effective than 2nd and 3rd generation cephalosporins to prevent UTI. The distribution of causative organisms was more diverse than usual UTI. The causative organisms were sensitive to the antibiotics used for prophylaxis in 29.5%, and resistant in 59.1%. After experience of BI, 40 percents of patients went to the surgical treatment including endoscopic injection of Deflux, 35% to new antibiotics for prophylaxis, 26% remain on the same antibiotics as the previous one. Conclusion : Based on our study results, preexisting renal scar might be one of the factors which should be considered in favor of early surgical interventions of VUR. Poor compliance and wrong selection of antibiotics such as cephalosporins are important underlying causes of breakthrough UTIs.

• Childhood Kidney Diseases
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• v.12 no.2
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• pp.178-185
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• 2008

Purpose : Our aim was to investigate the predictive factors for detecting grade III-V vesicoureteral reflux(VUR) in young infants less than 3 months with urinary tract infections (UTI). Methods : Data of infants who underwent ultrasonography and VCUG between January 2004 and September 2007 were reviewed. Age, gender, incidence of bacteremia, C-reactive protein(CRP) and imaging studies were compared between group I(grade III-V VUR) and group II (normal or grade I and II VUR) retrospectively. Sensitivity, specificity, positive and negative predictive values, odds ratio, and likelihood ratio of ultrasonography for high grade VUR were evaluated. Results : Among 54 enrolled infants(41 males, 13 females), 14 infants were group I and 40 infants were group II. In the group I, CRP level was significantly higher(6.11$\pm$5.18 vs. 3.27$\pm$3.45, P=0.025), and there were more ultrasonographic abnormal findings(71.4%, vs. 22.5%, P=0.002) compared with group II. However, ultrasonography was the only significant factor after adjusting with logistic regression(P=0.002). Incidence of bacteremia and abnormal DMSA findings were not significantly different in two groups. Sensitivity, specificity, and odds ratio of ultrasonography was 71.4%, 77.5%, 6.9 respectively. Negative predictive value was 88.6% and negative likelihood ratio was 0.37. Ultrasonography had significant negative likelihood ratio for grade III-V VUR, but missed 4 infants with grade III VUR. Conclusion : We could not find any alternative predictive factors to reduce VCUG in detecting high grade VUR. Therefore, VCUG must be considered in young infants less than 3 months with UTI.

• The Korean Journal of Nuclear Medicine
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• v.35 no.6
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• pp.378-388
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• 2001

Purpose: In this study, we developed a new method for the determination of renal depth with anterior and posterior renal scintigrams in a dual-head gamma camera, considering the attenuation factor $e^{-{\mu}x}$ of the conjugate-view method. Material and Method: We developed abdomen and kidney phantoms to perform experiments using Technetium-99m dimercaptosuccinic acid ($^{99m}Tc$-DMSA). The phantom images were obtained by dual-head gamma camera equipped with low-energy, high-resolution, parallel-hole collimators (ICONf, Siemens). The equation was derived from the linear integration of omission ${\gamma}$-ray considering attenuation from the posterior abdomen to the anterior abdomen phantom surface. The program for measurement was developed by Microsoft Visual C++ 6.0. Results : Renal depths of the phantoms were derived from the derived equations and compared with the exact geometrical values. Differences between the measured and the calculated values were the range of 0.1 to 0.7 cm ($0.029{\pm}0.15cm,\;mean{\pm}S.D.$). Conclusion: The present study showed that the use of the derived equations for renal depth measurements, combined with quantitative planar imaging using dual-head gamma camera, could provide more accurate results for individual variation than the conventional method.

• Childhood Kidney Diseases
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• v.7 no.2
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• pp.181-188
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• 2003

Purpose : Vesicoureteral reflux(VUR) is known to be the main cause of childhood hypertension and renal failure. Knowing its familial occurrence, we determined the incidence of VUR and renal scar in asymptomatic siblings of Korean patients with primary VUR Methods : A total of 50 siblings from 37 index patients were included. Voiding cystourethro-graphy(VCUG) and renal scintigraphy using $^{99m}Tc-DMSA$ were peformed in these siblings from June, 1994 to May, 2001, Index patients were classified into two groups according to the presence of VUR in their siblings, and the clinical factors of the index patients such as age, sex, grade of reflux and renal cortical defect were compared between the groups. Results : Among the 50 siblings, VUR were found in 8(16%) and renal cortical defects were detected in 8(16%) siblings respectively. The incidence of renal cortical defects was 87.5%(7 out of 8) in the VUR(+) siblings. There was a case of VUR(-) cortical defect in one sibling, presumed as a scar from an old VUR. There was no relationship among age, sex, grade of reflux and renal cortical defect of the index patient to the presence of VUR in siblings. Conclusion : This study confirmed a significant incidence of VUR(16%) and renal cortical defects(16%) in the asymptomatic siblings of patients with primary VUR in Korea. It Is resonable to recommend screening studies to the siblings of patients with VUR for the early detection and prevention of probable reflux nephropathy. (J K orean Soc Pediatr Nephrol 2003;7:181-188)