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Biomedical subjects

K Y Chung

Publications and source records attributed to K Y Chung.

At least 19 recordsLinked to original sources
PubMed2006

Urinary mononuclear cell and disease activity of systemic lupus erythematosus.

Mononuclear cells play a cardinal role in the pathogenesis of systemic lupus erythematosus (SLE). A high urine cytology score has been reported to be associated with lupus nephritis in relapse. The objective of this study was to examine the urinary mononuclear cell population of patients with lupus nephritis, and explore its correlation with lupus disease activity. We studied 12 patients with active lupus nephritis, 17 patients with lupus nephritis in remission, 12 SLE patients with no history of renal disease and 13 healthy subjects. Clinical disease activity was quantified by the SLE Disease Activity Index (SLEDAI). Mononuclear cell species in the urinary sediment were examined by immunocytochemistry. Patients with active lupus nephritis had significantly more mononuclear cells in the urinary sediment. The number of CD3+ cell was significantly elevated in the active lupus nephritis than the others (P < 0.001), while there was no significant difference in the number of CD20+ and CD56+ cell among patient groups. The total urinary mononuclear cell correlated significantly with the overall SLEDAI score (r = 0.58, P < 0.001) as well as the renal score (r = 0.57, P < 0.001). The number of urinary CD3+, but not CD20+ or CD56+, cell significantly correlated with the overall SLEDAI score (r = 0.46, P = 0.003) as well as the renal score (r = 0.40, p = 0.011). In nine patients with renal biopsy, the histological activity index correlated with the total urinary mononuclear cell (r = 0.75, P = 0.02), CD3+ (r = 0.69, P = 0.04) and CD20+ cell (r = 0.69, P = 0.04). We conclude that urinary mononuclear cell was markedly elevated in patients with active lupus, and the urinary mononuclear cell count correlated significantly with the SLEDAI score and histological activity. CD3+ and CD20+ cells are the major component of urinary mononuclear cell in SLE patients and their number correlates with lupus disease activity.

Adult↗
PubMed2006

Relation between number of prescribed medication and outcome in peritoneal dialysis patients.

BACKGROUND: Many patients with end-stage renal disease need to take a large number of medications. In the present study, we studied the magnitude of problem and explored the relationship between the number of prescribed medications and the clinical outcome of a large cohort of prevalent peritoneal dialysis (PD) patients. METHODS: We studied the medication list of 266 prevalent PD patients. Dialysis adequacy, residual renal function and nutritional assessment were also performed. The patients were followed for 33.7 +/- 20.7 months. RESULTS: On average, each patient required 4.7 +/- 1.8 type of medications or 10.0 +/- 4.9 tablets per day. 40 patients (15.0%) needed at least 7 types of medication; 33 patients (12.4%) had to take more than 15 tablets each day. There is a significant but weak correlation between the number of types of medication and the Charlson's comorbidity score (r = 0.252, p < 0.001). Despite the large number of medication prescribed, the blood pressure control, serum cholesterol level, and the use of aspirin after atherosclerotic disease remained suboptimal in many patients. By multivariate analysis, independent factors for patient survival were Charlson's comorbidity score, number of types of medication, duration of dialysis, overall SGA score, and mean arterial blood pressure. Each additional type of medication conferred 20% increase in risk of death (95% CI, 1.6-41.7%, p = 0.032), and the effect is independent on the Charlson's comorbidity score. The actual number of pills taken by a patient did not influence survival in this model. CONCLUSION: Our results indicate that the number of prescribed medications is related to the clinical outcome of PD patients. The number of prescribed medication may reflect the severity of uremic complications and comorbid diseases not reflected by the Charlson's comorbidity score. Nevertheless, dialysis physicians should carefully balance the clinical need of treating multiple medical conditions with the potential problems of a complicated therapeutic regimen.

Aged↗
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

Nitrogen and phosphorus removal from swine wastewater by intermittently aerated dynamic-flow system.

This study was performed to evaluate the effects of the volume fraction of an anaerobic reactor (VFAR) and SRT on the removal of T-N and T-P in both an intermittently aerated system (IAS) and intermittently aerated dynamic-flow system (IADS), respectively. When the VFAR in the total volume of reactor from both IAS and IADS are 13%, 7%, and 0% at 5 days of SRT, the removal efficiencies of T-P were 80-87%, 62-65% and <30%, respectively. However, it was observed from this study that the removal efficiencies of T-N and T-P were not correlated to VFAR at a predetermined SRT, producing greater than 5000 mg/L of MLVSS. Also, IADS was shown to have the greater buffer capacity and adaptability to resist the shock due to the loading of high concentration of N. Furthermore, IADS achieved over 80% of removal efficiency of N even at much lower C/N ratio of 4.7. Therefore, it seems that IADS has the significant advantages over other biological nutrients removal processes.

Air Movements↗
PubMed2002

Conjugated linoleic acid depresses the delta9 desaturase index and stearoyl coenzyme A desaturase enzyme activity in porcine subcutaneous adipose tissue.

Conjugated linoleic acid (CLA) has been shown to have an effect on subcutaneous fatty acid composition and has been reported to decrease stearoyl coenzyme A desaturase (SCD) activity by decreasing mRNA expression and(or) catalytic activity in rodents and rodent cell lines. This investigation was designed to study the effects of CLA, corn oil, or beef tallow supplementation on s.c. adipose tissue fatty acid composition, adiposity, SCD enzyme activity, and the delta9 desaturase index in piglets. Eighteen crossbred barrows 16 to 18 d of age were adapted to diet for 1 wk and then assigned randomly to one of three treatments: 1.5% added CLA, 1.5% added corn oil, or 1.5% added beef tallow. Barrows were penned individually and fed the supplemental oils for 35 d (to 25.6 +/- 0.6 kg BW). Subcutaneous adipose tissue samples were obtained after slaughter. Fatty acid composition of the s.c. adipose tissue differed for each fatty acid measured due to diet with the exception of 18:3. The concentrations of CLA trans-10, cis-12 and cis-9, trans-11 were elevated from nondetectable to 1.62 and 2.52 g/100 g lipid, respectively (P < 0.001 for both isomers). Conjugated linoleic acid decreased the delta9 desaturase index (P < 0.01) and SCD enzyme activity, expressed as nanomoles of palmitate converted to palmitoleate/(7 min x g of tissue) (P = 0.075) and nanomoles of palmitate converted to palmitoleate/(7 min 105 cells) (P= 0.056). Tallow-fed pigs had a greater proportion of large adipocytes (> 700 pL) and the greatest SCD activity. These data provide the first direct evidence that dietary CLA depresses SCD enzyme activity in porcine adipose tissue, which may in part be responsible for the depression of adiposity by CLA observed by others in market weight pigs.

Adipocytes↗
PubMed2001

Heparan sulfate proteoglycan expression in the optic chiasm of mouse embryos.

Previous studies have demonstrated that heparan sulfate (HS) proteoglycans (PGs) regulate neurite outgrowth through binding to a variety of cell surface molecules, extracellular matrix proteins, and growth factors. The present study investigated the possible involvement of HS-PGs in retinal axon growth by examining its expression in the retinofugal pathway of mouse embryos by using a monoclonal antibody against the HS epitope. Immunoreactive HS was first detected in all regions of the retina at embryonic day (E) 11. The staining was gradually lost in the central regions and restricted to the retinal periphery at later developmental stages (E12--E16). Prominent staining for HS was consistently found in the retinal fiber layer and at the optic disk, indicating a possible supportive role of HS-PGs in axon growth in the retina. At the ventral diencephalon, immunostaining for HS was first detected at E12, before arrival of any retinal axons. The staining matched closely the neurons that are immunopositive for the stage-specific embryonic antigen 1 (SSEA-1). At E13 to E16, when axons are actively exploring their paths across the chiasm, immunoreactivity for HS was particularly intense at the midline. This characteristic expression pattern suggests a role for HS-PGs in defining the path of early axons in the chiasm and in regulating development of axon divergence at the midline. Furthermore, HS immunoreactivity is substantially reduced at regions flanking both sides of the midline, which coincides spatially to the position of actin-rich growth cones from subpial surface to the deep regions of the optic axon layer at the chiasm. Moreover, at the threshold of the optic tract, immunoreactive HS was localized to deep parts of the fiber layer. These findings indicate that changes in age-related fiber order in the optic chiasm and optic tract of mouse embryos are possibly regulated by a spatially restricted expression of HS-PGs.

Animals↗
PubMed2001

Flux enhancement with gas injection in crossflow ultrafiltration of oily wastewater.

The gas injection technique was introduced to achieve flux improvement in cross-flow ultrafiltration of oil emulsion. By the nitrogen gas injection, homogeneous liquid phase oil/water emulsion was changed to heterogeneous gas- liquid phase. The injected gas causes positive effect of promoting turbulence, but it also has negative effect of decreasing the effective membrane area due to the partial occupation of membrane pores by bubbles. The efficiency of the gas injection was found out to be dependent on bubble fractions in the mixture: at sufficient bubble fractions the higher flux was observed. but at lower bubble fractions the flux rather decreased compared with that without gas injection. An attempt was made to explain the mechanisms for the dual aspects of gas injection. Turbulence dampening effect was also observed when the dependence of mass transfer coefficient on cross-flow rate was investigated with gas injection.

Air Movements↗
PubMed2001

Degradation of 1,3-dichloropropene by a soil bacterial consortium and Rhodococcus sp. AS2C isolated from the consortium.

A bacterial consortium capable of degrading the fumigant 1,3-D ((Z)- and (E)- 1,3-dichloropropene) was enriched from an enhanced soil. This mixed culture degraded (Z)- and (E)-1,3-D only in the presence of a suitable biodegradable organic substrate, such as tryptone, tryptophan, or alanine. After 8 months of subculturing at 2- to 3-week intervals, a strain of Rhodococcus sp. (AS2C) that was capable of degrading 1,3-D cometabolically in the presence of a suitable second substrate was isolated. (Z)-3-chloroallyl alcohol (3-CAA) and (Z)-3-chloroacrylic acid (3-CAAC), and (E)-3-CAA and (E)-3-CAAC were the metabolites of (Z)- and (E)- 1,3-D, respectively. (E)- 1,3-D was degraded faster than (Z)- 1,3-D by the strain AS2C and the consortium. AS2C also degraded (E)-3-CAA faster than (Z)-3-CAA. Isomerization of (E)- 1,3-D to (Z)- 1,3-D or the (Z) form to the (E) form did not occur.

Allyl Compounds↗
PubMed2001

Three cases of fistulae arising from gastrointestinal tract treated with endoscopic injection of Histoacryl.

Treatment of gastrointestinal fistula usually consists of conservative management and surgery as definite therapeutic measure. Histoacryl can be used to treat gastrointestinal fistula with no response to conservative management in surgically high-risk patients. We report here three cases of gastrointestinal fistula successfully treated with endoscopic injection of Histoacryl through a catheter into the internal opening and fistulous tract.

Enbucrilate↗
PubMed2001

Formation of DNA triple helix containing N(4)-(6-aminopyridin-2-yl)-2'-deoxycytidine.

A cytidinyl derivative, N(4)-(6-aminopyridin-2-yl)- 2'-deoxycytidine ((p)C), could interact with a CG base pair to support the triple-helix (triplex) formation of oligodeoxyribonucleotides. Characteristics of (p)C in the formation of both intramolecular triplex, i.e., a "paper clip type" triplex ((P)CT) and intermolecular triplex, i.e., a "linear type" triplex (LT) was monitored by optical methods and isothermal titration calorimetric measurements. Experimental results revealed that the LT with (p)C*CG internally was independent of the solution pH. Only single substitution of (p)C, situated internally but not terminally, facilitated the (P)CT formation by the UV thermal melting study at the neutral pH. However, the best stabilization of the PCT in acidic conditions occurred when (p)C at the end of the triplex rather than internally. In addition, an LT, but not a (P)CT, containing an alternating (p)CT(p)CT(p)C sequence, could be formed in the conditions of 20 mM MgCl(2) and/or 5 mM spermine. Thus, the presence of several nucleotides of (p)C in proximity along the Hoogsteen strand may lead to structural distortion such that the more flexible LT with multiple substitutions is formed in favor of the more rigid PCT.

Aminopyridines↗
PubMed2001

Thymoma with pseudosarcomatous stroma.

Thymoma with psuedosarcomatous stroma is a recently described, rare variant of thymomas that are characterized by having a biphasic histologic pattern which consists of both an epithelial and a spindle cell stromal component. So far only 11 cases having similar histologic findings have been reported worldwide. At this time we report a case of this rare variant of thymoma which occurred in a 53-year-old Korean man. This previously healthy patient presented with coughing and an anterior mediastinal mass was then detected radiographically. Mediastinal exploration revealed a 9 x 8 x 8 cm-sized well- encapsulated, ovoid, cystic mass. Histological examination showed a biphasic neoplasm composed of anastomosing nests of epithelial cells and somewhat cellular stromal spindle cells that had advanced degenerative changes. Immunohistochemical staining using the antibodies for cytokeratins, EMA, e-cadherin, and p75NGFR showed a strong expression of these markers in the epithelial component but no expression in the spindle stromal cells. The epithelial tumor cells showed no reactivity to CD5 and L26 and a high proportion of the infiltrated lymphocytes were the cortical type that expressed CD99 and terminal deoxynucleotidyl transferase. Ultrastructural examinations revealed tonofilaments in the spindle cells. Follow up has been done for 5 years after the surgical excision and the patient has been free of disease during that period. Similar to previous reports, this patient had a benign clinical course that was unassociated with myasthenia gravis which appears to be a characteristic of this histologic variant of thymoma. However, our case also showed advanced degenerative features and we could demonstrate ultrastructural evidence of epithelial differentiation in the stromal spindle cells that were not mentioned in the previously reported cases. Based on the results of our studies, we suggest this entity is a distinct type of organotypic thymoma that shows cortical differentiation and abundant cellular stroma.

Humans↗
PubMed2001

Cardiac arrhythmias in F-16 pilots during aerial combat maneuvers (ACMS): a descriptive study focused on G-level acceleration.

INTRODUCTION: It is well known that acceleration during centrifuge training provokes cardiac arrhythmias. However, there is little research regarding cardiac arrhythmia during actual flight. Therefore, to identify the kinds of cardiac arrhythmias that occur in response to the Aerial Combat Maneuvers (ACM) environment, we analyzed electrocardiograms (ECG) of 35 male pilots. METHODS: ECGs were recorded from 35 pilots (mean age 31 yr, range 27-39) from 1 h before take-off to 1 h after landing. G-load was simultaneously recorded. To see the patterns of the arrhythmia as Gz force increased, ECG data of each subject were classified into three G levels: a) G-level A was < +3 G; b) G-level B was > or = +3 G but < +6 G lasting longer than 3 s; and c) G-level C was > or = +6 G lasting longer than 3 s. RESULTS: Mean total flying time of the 35 pilots was 1475 h (range 578-3300). Arrhythmias were observed in 17 of the pilots (49%) during ECG recording. Four pilots (11.4%) experienced arrhythmias before take-off, 16 pilots (45.7%) inflight and 4 pilots (11.4%) after landing. Arrhythmias were recorded in 13 of 35 pilots (37.1%) at G-level A, in 10 of 35 pilots (28.6%) at G-level B and in 1 of 21 pilots (5%) at G-level C. During flight, unifocal premature ventricular contractions (PVC) were experienced by three of the subjects (8.6%); supraventricular premature beats (SVPB) by four subjects (11.4%), and PVCs with bigeminy by one subject (2.9%). Eight subjects (22.9%) experienced combined arrhythmias. CONCLUSION: There were no clinically significant arrhythmias recorded during ACM in these experienced pilots.

Acceleration↗
PubMed2000

Expression of chondroitin sulfate proteoglycans in the chiasm of mouse embryos.

Chondroitin sulfate (CS) proteoglycans have been implicated as molecules that are involved in axon guidance in the developing neural pathways. The spatiotemporal expression of CS was investigated in the developing retinofugal pathway in mouse embryos by using the CS-56 antibody. Immunoreactive CS was detected in inner regions of the retina as early as embryonic day 11 (E11). Its expression in subsequent stages of development followed a centrifugal, receding gradient that appeared to correlate with the sequence of axogenesis in the retina. In the chiasm, immunoreactive CS was expressed at E12, before the arrival of retinal axons. When the retinal axons navigated in the chiasm at E13-E14, immunoreactive CS remained at a low level in the optic fiber layer of the chiasm but was observed prominently in the caudal parts of the ventral diencephalon. This pattern followed closely the array of stage-specific-embryonic-antigen-1-positive neurons in the ventral diencephalon, with a V-shaped configuration that bordered the posterior boundary of the retinal axons, and a rostral raphe extension that ran across the decussating axons in the chiasm. Thus, the CS epitope is implicated in patterning the course of early retinal axons and in regulating axon divergence in the chiasm. At the lateral region of the chiasm, where the retinal axons cross the midline and approach the optic tract, a CS-immunopositive region coincided with the region in which active sorting of dorsal retinal axons from ventral retinal axons occurs. Moreover, at the threshold of the optic tract, the immunoreactive CS was restricted only to the deep part of the optic fiber layer, suggesting an inhibitory role of the CS epitope in repelling newly arrived axons to superficial regions of the optic tract during the development of chronotopic order at this part of the retinofugal pathway.

Animals↗
PubMed2000

Reaction monitoring of succinylation of collagen with matrix-assisted laser desorption/ionization mass spectrometry.

Succinylated collagen was synthesized by the reaction of collagen with succinic anhydride under basic conditions for one hour. Using the matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) technique, the reaction products were directly identified without multi-step separation processes. MALDI-MS monitored the reaction more accurately than the conventional method of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). From the change in molecular mass during the reaction, it is observed that about 28 succinyl groups are attached to the collagen strand.

Animals↗
PubMed2000

Inhibitory effect of sodium salicylate on nitric oxide production from TM4 sertoli cells.

Nitric oxide (NO) has been proposed to play a role in a variety of inflammatory diseases. Sodium salicylate (NaSal) is the most commonly used anti-inflammatory agent. We investigated whether NaSal can diminish the production of NO in TM4 Sertoli cells. TM4 Sertoli cells produced a small amount of NO upon treatment with recombinant interferon-gamma (rIFN-gamma). The effect of rIFN-gamma was enhanced markedly by the addition of recombinant TNF-alpha (rTNF-alpha) in a dose-dependent manner. NaSal (10 and 20 mM) significantly inhibited NO production from TM4 Sertoli cells induced by rIFN-gamma plus rTNF-alpha. In addition, rIFN-gamma in combination with rTNF-alpha showed a marked increase of the expression of inducible NO synthase (iNOS) protein. Western blot analysis revealed that NaSal (10 and 20 mM) blocked a step of iNOS protein synthesis. The rIFN-gamma plus rTNF-alpha-induced nuclear factor-kappaB (NF-kappaB) activation was significantly blocked by NaSal (10 and 20 mM). On the other hand, neither staurosporine nor polymyxin B significantly inhibited NO production from TM4 Sertoli cells induced by rIFN-gamma plus rTNF-alpha. The present results indicate that NaSal inhibits rIFN-gamma plus rTNF-alpha-induced NO production in TM4 Sertoli cells via the signal transduction pathway of NF-kappaB activation.

Animals↗
PubMed2000

Axon routing at the optic chiasm after enzymatic removal of chondroitin sulfate in mouse embryos.

The effects of removing chondroitin sulfate from chondroitin sulfate proteoglycan molecules on guidance of retinal ganglion cell axons at the optic chiasm were investigated in a brain slice preparation of mouse embryos of embryonic day 13 to 15. Slices were grown for 5 hours and growth of dye-labeled axons was traced through the chiasm. After continuous enzymatic digestion of the chondroitin sulfate proteoglycans with chondroitinase ABC, which removes the glycosaminoglycan chains, navigation of retinal axons was disrupted. At embryonic day 13, before the uncrossed projection forms in normal development, many axons deviated from their normal course, crossing the midline at aberrant positions and invading the ventral diencephalon. In slices from embryonic day 14 embryos, axons that would normally form the uncrossed projection at this stage failed to turn into the ipsilateral optic tract. In embryonic day 15 slices, enzyme treatment caused a reduction of the uncrossed projection that develops at this stage. Growth cones in enzyme-treated slices showed a significant increase in the size both before and after they crossed the midline. This indicates that responses of retinal axons to guidance signals at the chiasm have changed after removal of the chondroitin sulfate epitope. We concluded that the chondroitin sulfate moieties of the proteoglycans are involved in patterning the early phase of axonal growth across the midline and at a later stage controlling the axon divergence at the chiasm.

Animals↗