Biomedical subjects

Y S Kim

Publications and source records attributed to Y S Kim.

At least 55 records · Page 3Linked to original sources

PubMed2004

The effect of a nitric oxide donor on endogenous endothelin-1 expression in renal ischemia/reperfusion injury.

The balance between nitric oxide (NO) and endothelin-1 (ET-1) production is essential to the vascular function that controls organ perfusion. Elevated ET-1 levels in the peritubular capillary network following renal transplantation may be associated with renal allograft rejection. Administration of a nitric oxide donor during the preischemic period has been shown to protect kidney against ischemia-reperfusion injury, but the mechanism underlying this therapeutic benefit remains incompletely understood. We hypothesized that early administration of the NO donor sodium nitroprusside (SNP) may suppress ET-1, thereby improving renal function in an ischemia/reperfusion injury. Sprague-Dawley rats were subjected to 60 minutes of renal warm ischemia and contralateral nephrectomy. Renal biopsies were performed prior to ischemia and reperfusion, and at 1 hour and 48 hours after reperfusion. The animals were divided into four groups: sham group without warm ischemia; early SNP group (SNP given before ischemia); late SNP group (SNP given before reperfusion); and ischemic control. ET-1 expression was assessed by semiquantitative analysis with immunohistochemical stain using ET-1 monoclonal antibody and hematoxylin-eosin staining. Serum creatinine was measured at 48 hours after reperfusion. There were significant improvements in all parameters of the early compared with the late SNP group and the ischemic control, but there was no difference between the late SNP group and the ischemic control. These data suggest that early administration of SNP in renal ischemia-reperfusion improves renal function by suppressing ET-1 expression.

Animals↗

PubMed2004

Prevention of primary nonfunction after canine liver allotransplantation: the effect of gadolinium chloride.

PURPOSE: Effective suppression of Kupffer cell function is believed to contribute to the prevention of preservation/reperfusion injury. In this study, effect of gadolinium, a synthetic Kupffer cell suppressant, on the reperfusion injury was examined using a canine partial liver transplantation model. METHODS: About a 70% partial liver segment was harvested and reimplanted in a mongrel recipient dog weighing 20 to 25 kg. Gadolinium chloride (10 mg/kg) was infused via the cephalic vein 24 hours before harvest of the partial liver (gadolinium group, n = 5). Serum aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), and morphologic grading of graft were compared with those of a control group (n = 5). Statistical analysis was done with an independent t-test. RESULTS: Average total ischemic time was 4 hours and 27 minutes. At 1 hour after reperfusion, there were no significant differences in AST, ALP, or LDH levels, or pathologic scores. At 48 hours after reperfusion, AST (P = .03) and LDH (P = .05) levels were significantly lower in the gadolinium group. CONCLUSION: Kupffer cell blockade using gadolinium chloride may be effective to reduce ischemia reperfusion injury, but the effect is not evident at an early stage of reperfusion.

Animals↗

PubMed2004

Exchange living-donor kidney transplantation: diminution of donor organ shortage.

BACKGROUND: To alleviate the organ shortage, the use of more living donors is strongly recommended world wide. A living donor exchange (swap) program was launched in Korea. After the success of a direct swap program between two families, we have developed the swap-around program to expand the donor pool by enrolling many kinds of unrelated donors. Herein, we report our results of a living donor exchange program. METHODS: This retrospectively review of 978 recipients of kidney transplants from living donors, included analysis of donor-recipient relationships, mode of donor recruitment, episodes of acute rejection, and 5-year patient/graft survivals. RESULTS: Transplantation was performed in 101 patients (10.3%) by way of the swap program. The proportion of swap patients among the number of unrelated donor renal transplants has been increasing from 4.2% to 46.6%. The incidence of acute rejection and 5-year patient/graft survival rates were comparable between the groups. CONCLUSIONS: We have achieved some success in reducing the organ shortage with a swap program in addition to our current unrelated living donor programs without jeopardizing graft survival. Potentially exchangeable donors should undergo strict medical evaluation by physicians and social evaluation by social workers and coordinators as a pre-requisite for kidney transplantation. Expanding the swap around program to a regional or national pool could be an option to reduce the organ donor shortage in the future.

Blood Group Incompatibility↗

PubMed2004

Pool of dust particles over the Asian continent: balloon-borne optical particle counter and ground-based lidar measurements at Dunhuang, China.

Measurements of aerosols were made in 2001 and 2002 at Dunhuang (40 degrees 00'N, 94 degrees 30'E), China to understand the nature of atmospheric particles over the desert areas in the Asian continent. Balloon-borne measurements with an optical particle counter suggested that particle size and concentration had noticeable peaks in super micron size range not only in the boundary mixing layer but also in the free troposphere. Super-micron particle concentration largely decreased in the mid tropopause (from 5 to 10 km; above sea level, a.s.l.). Lidar measurements made during August 2002 at Dunhuang suggested the possibility that mixing of dust particles occurred from near the ground to about 6 km even under calm weather conditions, and a large depolarization ratio of particulate matter was found in the aerosol layer. The top of the aerosol layer was found at heights of nearly 6 km (a.s.l.). It is strongly suggested that nonspherical dust particles (Kosa particles) frequently diffused in the free atmosphere over the Taklamakan desert through small-scale turbulences and are possible sources of dust particles of weak Kosa events that have been identified in the free troposphere not only in spring but also in summer over Japanese archipelago. Electron microscopic experiments of the particles collected in the free troposphere confirmed that coarse and nonspherical particles observed by the mineral particle were major components of coarse mode (diameter larger than 1 microm) below about 5 km over Dunhuang, China.

Aerosols↗

PubMed2004

Invasive intraductal papillary mucinous tumor of the pancreas with simultaneous invasion of the stomach and duodenum.

An 81-year-old woman was admitted with epigastric pain and weight loss. She had been diagnosed with an intraductal papillary mucosal tumor (IPMT) 7 years previously, but had refused surgery for religious reasons. Esophagogastroduodenoscopy revealed a nodular, elevated lesion that was discharging mucin into the duodenal bulb and posterior wall of the upper body of the stomach. Endoscopic ultrasonography, abdominal computed tomography, and endoscopic retrograde cholangiography were carried out, and a highly invasive IPMT with simultaneous invasion of the stomach and duodenum was diagnosed.

Aged↗

PubMed2004

Increased expression of caveolin-1 and microvessel density correlates with metastasis and poor prognosis in clear cell renal cell carcinoma.

OBJECTIVE: To investigate the relationship of caveolin-1 expression and microvessel density (MVD), a reflection of angiogenesis, with metastasis and prognosis in patients with clear cell renal cell carcinoma (RCC). PATIENTS AND METHODS: Formalin-fixed, paraffin-embedded tissue sections of clear cell RCC from 67 patients who had undergone radical nephrectomy were stained immunohistochemically with specific antibodies against caveolin-1 and CD34. Caveolin-1 immunostaining was semi-quantitatively estimated based on the proportion (percentage of positive cells) and intensity. MVD was determined with CD34-stained slides. The expression pattern of caveolin-1 and MVD was compared with the clinicopathological variables. RESULTS: Eighteen patients had either synchronous or metachronous metastases and 11 died during the follow-up. Caveolin-1 intensity was significantly correlated with tumour size (P = 0.005), TNM stage (P = 0.028), M stage (P = 0.012), grade (P = 0.015), and metastasis (synchronous or metachronous; P < 0.001). The caveolin-1 proportion (P = 0.037) and MVD (P = 0.011) were significantly correlated with metastasis. MVD was correlated with caveolin-1 intensity (r = 0.385, P = 0.001) and caveolin-1 proportion (r = 0.388, P = 0.001). There was no difference in the expression of caveolin-1 and MVD between primary and metastatic sites. The survival of patients with higher caveolin-1 intensity was significantly worse than that of patients with lower caveolin-1 intensity. Multivariate analyses indicated that only M-stage was an independent prognostic factor for cancer-specific survival and caveolin-1 expression was not an independent factor. CONCLUSIONS: Increased expression of caveolin-1 and MVD is associated with metastasis and a worse prognosis in clear cell RCC. Caveolin-1 expression is correlated with MVD. These results suggest that caveolin-1 may be important in the progression of clear cell RCC and angiogenesis may be affected by caveolin-1 during the progression of RCC.

Adult↗

PubMed2004

In vivo and in vitro evaluation of the heparin management test versus the activated coagulation time for monitoring anticoagulation level in aprotinin-treated patients during cardiac surgery.

INTRODUCTION: Monitoring whole blood anticoagulation therapy with the activated coagulation time (kaolin ACT) and the heparin management test (HMT) were correlated in vivo with the plasma anti-activated factor X (anti-Xa) heparin concentration in patients who received variable doses of aprotinin and in vitro in the presence of increasing concentrations of aprotinin. METHODS: In 38 elective cardiac surgical patients who received an average heparin dose of 400 IU/kg and an average total aprotinin dose of 3.6 10(6) kallikrein-inhibiting units (KIU), ACT and HMT were measured in duplicate 6 times intraoperatively at predetermined intervals. Blood samples at each interval were also assayed for the anti-Xa plasma heparin concentration with the IL Test heparin chromogenic assay. The influence of increasing concentrations of aprotinin on HMT and ACT was also measured in vitro by using blood samples containing 6 IU/mL heparin from 6 additional patients after adding specific aliquots of aprotinin to achieve concentrations of 50, 100, 200, and 300 KIU/mL aprotinin. Linear regression analysis was used to compare HMT and ACT against anti-Xa. A P level <.05 was required for statistical significance. RESULTS: Duplicate measurements were taken at all intervals, and HMT and ACT values were significantly correlated, both with each other (r = 0.86; P < .01) and with anti-Xa activity (HMT, r = 0.81 [P < .01]; ACT, r = 0.71 [P < .01]). Aprotinin prolonged both the kaolin ACT and the HMT time in a dose-dependent manner (P < .05), and its influence was significantly less in vivo on the HMT time than on the kaolin ACT (P < .001). CONCLUSIONS: The abilities of the HMT and the kaolin ACT to measure anticoagulation effects were not significantly different. Aprotinin prolonged both the kaolin ACT and the HMT time in a dose-dependent manner, but the HMT was significantly less affected by aprotinin in vivo. The HMT is a reliable alternative to measuring the ACT in cardiac operations and may offer greater accuracy in aprotinin-treated patients.

Adult↗

PubMed2003

Slide-rule-like property of Wigner's little groups and cyclic S matrices for multilayer optics.

It is noted that 2x2 "S" matrices in multilayer optics can be represented by the Sp(2) group whose algebraic property is the same as the group of Lorentz transformations applicable to two spacelike and one timelike dimensions. It is also noted that Wigner's little groups have a slide-rule-like property that allows us to perform multiplications by additions. It is shown that these two mathematical properties lead to a cyclic representation of the S matrix for multilayer optics, as in the case of ABCD matrices for laser cavities. It is therefore possible to write the N-layer S matrix as a multiplication of the N single-layer S matrices resulting in the same mathematical expression with one of the parameters multiplied by N. In addition, it is noted, as in the case of lens optics, that multilayer optics can serve as an analog computer for the contraction of Wigner's little groups for internal space-time symmetries of relativistic particles.

Journal Article↗

PubMed2003

Lens optics as an optical computer for group contractions.

It is shown that the one-lens system in para-axial optics can serve as an optical computer for contraction of Wigner's little groups and an analog computer that transforms analytically computations on a spherical surface to those on a hyperbolic surface. It is shown possible to construct a set of Lorentz transformations which leads to a 2x2 matrix whose expression is the same as those in the para-axial lens optics. It is shown that the lens focal condition corresponds to the contraction of the O(3)-like little group for a massive particle to the E(2)-like little group for a massless particle, and also to the contraction of the O(2,1)-like little group for a spacelike particle to the same E(2)-like little group. The lens-focusing transformations presented in this paper allow us to continue analytically the spherical O(3) world to the hyperbolic O(2,1) world, and vice versa. Since the traditional role of Wigner's little groups has been to dictate the internal space-time symmetries of massive, massless, and imaginary-mass particles, the one-lens system provides a unification of those symmetries.

Journal Article↗

PubMed2003

Resistance to extended-spectrum cephalosporins and mortality in patients with Citrobacter freundii bacteremia.

BACKGROUND: This study was performed to characterize the clinical features and to identify the risk factors for resistance to extended-spectrum cephalosporins (ESCs) and for mortality in patients with Citrobacter freundii bacteremia. PATIENTS AND METHODS: 105 patients (aged > or = 15 years) with C. freundii bacteremia in 1991-2000 were retrospectively analyzed. RESULTS: Nosocomial acquisition was identified in 78.1% of the patients. Hepatic, biliary and pancreatic disease was the most common underlying disease (65.7%) and the biliary tract was the most common site of infection (50.5%). The overall resistance rate to ESCs was 59.0% and was significantly associated with hepatic, biliary and pancreatic disease, recent surgery and procedure, biliary drainage catheter and previous antibiotic therapy in univariate analysis. However, only previous antibiotic therapy with ESCs (OR = 5.0, 95% CI 1.6-15.7, p = 0.006) and recent surgery or procedure (OR = 3.1, 95% CI 1.1-8.4, p = 0.03) were strong, independent risk factors in multivariate analysis. Mortality directly related to C. freundii bacteremia was 21.9% and there was no difference between cases with resistance and susceptibility to ESCs (19.4% vs 25.6%; p = 0.45). Mortality was significantly associated with rapidly fatal or ultimately fatal underlying disease, a solid tumor, septic shock and polymicrobial bacteremia in univariate analysis. Among patients who had therapeutic surgical procedures, mortality was lower (4.5%, p = 0.04). Multivariate analysis revealed rapidly or ultimately fatal disease, septic shock and polymicrobial bacteremia as independent prognostic factors. CONCLUSION: Biliary infection was the leading cause of C. freundii bacteremia. Previous antibiotic therapy, especially with ESCs, frequently predisposed for resistance to these antibiotics. However, resistance to ESCs was not associated with increased mortality.

Adolescent↗

PubMed2003