Reviews and Original Articles Lipoprotein(A) and Apolipoprotein(A) Phenotypes in Patients with End-Stage Renal Disease

Objective

To evaluate the distribution pattern of apolipoprotein(a) [Apo(a)] phenotypes in Koreans and the effect of dialysis modality on serum lipoprotein(a) [Lp(a)] concentration according to apo(a) phenotype in patients with end-stage renal disease (ESRO).

Design

Cross-sectional study.

Setting

A university hospital. Participants: 153 normal controls, 99 hemodialysis (HO) patients and 82 continuous ambulatory peritoneal dialysis (CAPO) patients.

Main Outcome Measures

Fasting serum Lp(a), lipids, and apo(a) phenotypes were measured.

Results

The frequencies of the subjects with apo(a) phenotypes of high-molecular weight only, including S3, S4, or S5 or null type were 95.4% of control, 100% of HO patients, and 95.1% of CAPO patients. The frequent apo(a) phenotypes in Koreans consisted of S4, S4S5, S5, and S5S5 isoforms. Significant difference was found in serum Lp(a) concentration among controls and HO and CAPO patients [median (interquartile range): 0.05 g/L, (0.01 0.19); 0.19g/L, (0.10 0.35); 0.63g/L, (0.28 0.90), p< 0.001]. Lp(a) levels in CAPO patients were significantly higher than in HO patients for all four common apo(a) isoforms found in Korean subjects. CAPO patients had higher total and LOL cholesterol levels, and higher ApoB levels than H O patients. Significant differences were found in serum albumin levels between controls and HO and CAPO patients (44 ± 3 g/L, 40 ± 4 g/L, 32 ± 7 g/L, respectively, p < 0.05). There were significant inverse correlations between serum albumin and Lp(a) (r = -0.33, p < 0.01), total cholesterol (r = -0.31, p < 0.01), LOL (r = -0.39, p < 0.01) or ApoB (r = -0.35, p < 0.01) in ESRO patients. A significant positive correlation was found between serum albumin and ApoA1 (r = 0.24, p < 0.01).

Conclusion

These findings indicate that Koreans have mainly high -molecular weight apo(a) phenotypes and serum Lp(a) is elevated in CAPO patients compared to HO patients for common apo(a) phenotypes, which may contribute to the frequent cardiovascular mortality in CAPO patients.

Reduced Oxidative Stress in Hypoalbuminemic CAPD Patients

Objective

Albumin is one of the plasma antioxidants. The higher incidence of cardiovascular disease in dialysis patients with hypoalbuminemia may be related to decreased antioxidant capacity resulting from low serum albumin. We evaluated malondialdehyde (MDA), a marker of oxidative stress, and total antioxidant capacity (TAC) in relation to serum albumin in continuous ambulatory peritoneal dialysis (CAPD) patients.

Patients and Methods

In this cross-sectional study, we measured MDA, TAC, albumin, uric acid (another important plasma antioxidant), prealbumin, and C-reactive protein (CRP) in the blood of 66 CAPD patients and 30 normal controls. Twenty-two CAPD patients with albumin less than or equal to 3.5 g/dL were divided into two groups: In the experimental group ( n = 11), MDA, TAC, and CRP were measured before and after repeated infusion of 20% albumin 100 mL daily for 7 days. In the control group ( n = 11), the same parameters were measured without albumin infusion.

Results

CAPD patients had lower albumin and higher MDA, TAC, and uric acid than normal controls. There were positive correlations between albumin and TAC or uric acid in CAPD patients. Contrary to our expectation, there was also positive correlation between albumin and MDA in CAPD patients ( r = 0.37, p = 0.004). MDA showed a positive correlation with TAC. Uric acid was correlated with TAC. It did not, however, show correlation with MDA. Log CRP was negatively correlated with albumin, but did not show correlation with MDA or TAC. Prealbumin was correlated with MDA, TAC, albumin, and uric acid. Serum albumin in the experimental group increased from 2.5 ± 0.3 g/dL to 3.6 ± 0.2 g/dL ( p < 0.001) at the end of repeated infusions. No changes were seen in MDA, TAC, and CRP in either group.

Conclusions

The present study suggests that lipid peroxidation is increased in CAPD patients and that this is not due to weakening of antioxidant defenses of plasma. Increased TAC was mainly caused by a higher level of uric acid. Reduced, rather than increased, MDA in hypoalbuminemic patients and lack of effects of albumin infusion on levels of MDA suggest that the frequent occurrence of cardiovascular disease in dialysis patients with hypoalbuminemia is not due to the decrease in antioxidant capacity resulting from low serum albumin.

Analytical and Clinical Performance of the Nanopia Krebs von den Lungen 6 Assay in Korean Patients With Interstitial Lung Diseases

BACKGROUND

Krebs von den Lungen 6 (KL-6) is a sensitive marker for diagnosing, monitoring, and predicting the prognoses of interstitial lung diseases (ILDs). This study aimed to evaluate the performance of the Nanopia KL-6 assay (Sekisui Medical, Tokyo, Japan) and to test the relationship between KL-6 concentrations and clinical results.

METHODS

In total, 230 patients diagnosed as having ILDs were enrolled. All underwent high-resolution computed tomography (HRCT) followed by the pulmonary function test (PFT). We also enrolled 116 disease controls and 200 healthy controls. Evaluation of the Nanopia KL-6 assay involved determination of precision, linearity, and limit of quantification (LOQ). Results from the Nanopia KL-6 assay were compared with those from ELISA and correlated with the HRCT and PFT results.

RESULTS

The within-laboratory precisions were <2% of CV, and linearity was acceptable between 52.2 and 4,966.5 U/mL. The LOQ was 45.2 U/mL. Nanopia and ELISA results were strongly correlated (r=0.979). The average concentration of KL-6 was greater in ILD patients (711.5 U/mL) than in the disease (168.4 U/mL) and healthy (209.4 U/mL) controls. Serum KL-6 concentrations were strongly and moderately correlated with the extent of lung involvement and presence of typical HRCT abnormalities, respectively, and moderately correlated with PFT parameters.

CONCLUSIONS

The overall analytical and clinical performance of the Nanopia KL-6 assay was acceptable. Our study is the first to compare assay platforms and show correlations between KL-6 concentrations and HRCT or PFT results in Korean ILD patients.

Plasma Neutrophil Gelatinase-Associated Lipocalin as a Marker of Tubular Damage in Diabetic Nephropathy

Background

An increase in neutrophil gelatinase-associated lipocalin (NGAL) indicates tubular injury. Diabetic nephropathy causes typical changes in the kidney, characterized by glomerulosclerosis and eventual tubular damage. We validated the usefulness of plasma NGAL (pNGAL) as a biomarker of tubular damage in patients with diabetic nephropathy.

Methods

We included 376 patients with diabetes mellitus (260 patients with chronic renal insufficiency who had not received hemodialysis and 116 hemodialyzed due to diabetic nephropathy) and 24 healthy controls. Patients with chronic renal insufficiency were divided into three groups according to urinary albumin excretion (UAE) levels. pNGAL levels were measured using the Triage NGAL test (Alere, San Diego, CA, USA) and were compared between groups. We also examined whether pNGAL level was related to the degree of albuminuria and cystatin C-based glomerular filtration rate (GFR).

Results

Mean pNGAL levels of the healthy controls, chronic renal insufficiency patients with diabetes mellitus, and hemodialyzed patients were 61.9±5.3 ng/mL, 93.4±71.8 ng/mL, and 1,536.9±554.9 ng/mL, respectively. pNGAL level increased significantly in patients with severe albuminuria (P<0.001) and had a moderate correlation with the degree of albuminuria (r=0.467; P<0.001) and GFR (r=0.519; P<0.001). Multivariate regression analysis showed that the pNGAL level was associated with tubular damage independent of patient age, sex, and GFR.

Conclusions

pNGAL level independently reflects the degree of tubular damage in patients with diabetic nephropathy. Measurement of pNGAL, combined with UAE, would enable simultaneous, highly reliable assessments of tubular damage for such patients.

Evaluation of the 1B Equation to Estimate Glomerular Filtration Rate in Pediatric Patients with Cancer

The 1B equation is recommended for calculating the glomerular filtration rate (GFR) in children. Since few reports have evaluated the performance of the 1B equation, we investigated the performance of estimated GFR (eGFR) equations with the blood urea nitrogen (BUN) variable for pediatric cancer patients. In total, 203 children with cancer who underwent measured GFR (mGFR) assessment were enrolled. The median (range) mGFR and eGFR calculated using the updated Schwartz equation were 118 (43–241) and 135 (34–257) mL/min/1.73 m², respectively. The bias, precision (root mean square error [RMSE]), and accuracy (P30, mGFR±30%) of three eGFR equations including updated Schwartz, 1B, and full age spectrum (FAS) were compared. The median bias (mL/min/1.73 m²) was: updated Schwartz, 8.5; 1B, −9.0; and FAS, 4.2. The biases for all three eGFR equations were significantly different from zero. The P30 was: updated Schwartz, 63.5%; 1B, 66.0%; and FAS, 66.0%. The RMSE was the lowest for the 1B equation (40.4), followed by FAS (42.3), and updated Schwartz (45.5). The median eGFR/mGFR ratio for the eGFR equations decreased with age and reduced kidney functions (i.e., increased creatinine and BUN concentrations). The bias may be further reduced by using the average from two equations, such as the updated Schwartz and 1B, or FAS equation, rather than using the updated Schwartz or 1B equation alone. The use of the 1B equation may underestimate the GFR. Using creatinine and BUN variables in the eGFR equation may yield a more accurate estimate of the GFR in pediatric cancer patients.

Effect of the Standardization of Diagnostic Tests on the Prevalence of Diabetes Mellitus and Impaired Fasting Glucose

BACKGROUND

Without standardization of medical laboratory's testing practices, there is an increase in false diagnoses when relying on test results. However, the effect of test standardization is difficult to assess numerically. This study's purpose is to quantify the effect of the standardization level of a laboratory on the prevalence of diabetes mellitus (DM) and impaired fasting glucose (IFG).

METHODS

Laboratories were classified into three levels: 'highly-standardized laboratory,' 'basically-standardized laboratory,' and 'non-standardized laboratory.' Based on the results of Korean External Quality Assessment Scheme (KEQAS), the cutoff values for diagnosis of DM and IFG were recalculated, given false positive and false negative rates.

RESULTS

The prevalence of DM and IFG in the population as a whole was estimated using the 2013 Korea National Health and Nutrition Examination Survey (KNHANES) database. When the prevalence of DM from KNHANES was 11.88% (95% confidence interval [CI], 10.59%-13.17%), the proportion with a systematic false error ranged from 10.91% (95% CI, 9.65%-12.17%) to 13.09% (95% CI, 11.74%-14.45%). The prevalence of IFG varied from 13.59% (95% CI, 12.25%-14.91%) to 40.49% (95% CI, 38.54%-42.43%), in contrast to 24.58% (95% CI, 22.85%-26.31%) of the reference value. The prevalence of DM and IFG tended to be over- and under-estimated more as the laboratory standardization level became lower, respectively.

CONCLUSION

Our study proved that standardization of clinical laboratory tests is an important factor affecting the prevalence estimation of national disease statistics based on the simulation using KNHANES data.

Budget Impact of the Accreditation Program for Clinical Laboratories on Colorectal Cancer Screening via Fecal Immunochemical Testing: Results from the National Cancer Screening Program in Korea

Background

False-positive fecal immunochemical test (FIT) results in the National Cancer Screening Program (NCSP) for colorectal cancer may lead to unnecessary procedures, such as colonoscopies, increasing the medical costs. We estimated reductions in the cost of National Health Insurance according to the accreditation status of screening facilities participating in the NCSP for colorectal cancer.

Methods

We used data collected between 2007 and 2010 from NCSP and the Korea Central Cancer Registry to identify patients with colorectal cancer. We also ascertained the history of the accreditation of each facility by the Korean Laboratory Accreditation Program (KLAP). Budget impact was defined as a reduction in medical costs achieved when the false-positive rate of the non-accredited facilities decreased relative to that of the accredited facilities.

Results

A total of 3,285 screening facilities participated in the NCSP. Of these, 196 were accredited by the KLAP. The false-positive rate of the accredited facilities was 2.47%, and that of the non-accredited facilities was 6.83%. Medical costs were estimated to be reduced by approximately 19 million US dollars (USD), and the cost of detecting one case of colorectal cancer was estimated to decrease from 9,212 USD to 7,332 USD if the false-positive rate of non-accredited facilities were decreased to that of the accredited facilities. Clinics were estimated to have the largest associated cost reduction.

Conclusions

Quality assurance in clinical laboratories could lower false-positive rates and prevent the use of unnecessary procedures, ensuring patient safety and increasing the cost-effectiveness of FIT screening in the NCSP for colorectal cancer.

Accuracy Assessment of Five Equations Used for Estimating the Glomerular Filtration Rate in Korean Adults

BACKGROUND

We aimed to assess the performance of the five creatinine-based equations commonly used for estimates of the glomerular filtration rate (eGFR), namely, the creatinine-based Chronic Kidney Disease Epidemiology Collaboration (CKD-EPIcr), Asian CKD-EPI, revised Lund-Malmö (revised LM), full age spectrum (FAS), and Korean FAS equations, in the Korean population.

METHODS

A total of 1,312 patients, aged 20 yr and above who underwent ⁵¹Cr-EDTA GFR measurements (mGFR), were enrolled. The bias (eGFR-mGFR) and precision (root mean square error [RMSE]) were calculated. The accuracy (P30) of four eGFR equations was compared to that of the CKD-EPIcr equation. P30 was defined as the percentage of patients whose eGFR was within±30% of the mGFR.

RESULTS

The mean bias (mL·min⁻¹·1.73 m⁻²) of the five eGFR equation was as follows: CKD-EPIcr, -0.6; Asian CKD-EPI, 2.7; revised LM, -6.5; FAS, -2.5; and Korean FAS, -0.2. The bias of the Asian CKD-EPI, revised LM, and FAS equations showed a significant difference from zero (P<0.001). The RMSE values were as follows: CKD-EPIcr, 15.6; Asian CKD-EPI, 15.6; revised LM, 17.9; FAS, 16.3; and Korean FAS, 15.8. There were no significant differences in the P30 except for the Asian CKD-EPI equation: CKD-EPIcr, 76.6%; Asian CKD-EPI, 74.7%; revised LM, 75.8%; FAS, 76.0%; and Korean FAS, 75.8%.

CONCLUSIONS

The CKD-EPIcr and Korean FAS equations showed equivalent analytical and clinical performances in the Korean adult population.

Effect of Accreditation on Accuracy of Diagnostic Tests in Medical Laboratories

Background

Medical laboratories play a central role in health care. Many laboratories are taking a more focused and stringent approach to quality system management. In Korea, laboratory standardization efforts undertaken by the Korean Laboratory Accreditation Program (KLAP) and the Korean External Quality Assessment Scheme (KEQAS) may have facilitated an improvement in laboratory performance, but there are no fundamental studies demonstrating that laboratory standardization is effective. We analyzed the results of the KEQAS to identify significant differences between laboratories with or without KLAP and to determine the impact of laboratory standardization on the accuracy of diagnostic tests.

Methods

We analyzed KEQAS participant data on clinical chemistry tests such as albumin, ALT, AST, and glucose from 2010 to 2013. As a statistical parameter to assess performance bias between laboratories, we compared 4-yr variance index score (VIS) between the two groups with or without KLAP.

Results

Compared with the group without KLAP, the group with KLAP exhibited significantly lower geometric means of 4-yr VIS for all clinical chemistry tests (P<0.0001); this difference justified a high level of confidence in standardized services provided by accredited laboratories. Confidence intervals for the mean of each test in the two groups (accredited and non-accredited) did not overlap, suggesting that the means of the groups are significantly different.

Conclusions

These results confirmed that practice standardization is strongly associated with the accuracy of test results. Our study emphasizes the necessity of establishing a system for standardization of diagnostic testing.

Comparison of Thyroglobulin Measurements Using Three Different Immunoassay Kits: A BRAMHS Tg-Plus RIA Kit, a BRAMHS hTg Sensitive Kryptor Kit, and a Beckman Coulter ACCESS Immunoassay Kit

BACKGROUND

Second-generation thyroglobulin immunometric assays (Tg-IMAs) have been developed with improved sensitivity. Our aim was to compare the diagnostic value of Tg-IMA measurements using a Kryptor (BRAHMS AG) kit (Tg-K) and an ACCESS (Beckman Coulter) kit (Tg-A) with that of the first-generation Tg measurement using a Tg-plus (BRAHMS AG) kit (Tg+).

METHODS

We enrolled 82 differentiated thyroid cancer patients who underwent total thyroidectomy with radioactive iodine remnant ablation and who underwent diagnostic whole body scan using recombinant human thyroid stimulating hormone (rhTSH). The Tg+, Tg-K, and Tg-A were measured before rhTSH administration during levothyroxine treatment (suppressed Tg) from the same sample. Serum Tg+ was measured after rhTSH stimulation (stimulated Tg).

RESULTS

Suppressed Tg+ was more significantly correlated with suppressed Tg-K (R²=0.919, P<0.001) than with suppressed Tg-A (R²=0.536, P<0.001). The optimal cut-off values of suppressed Tg+, Tg-K, and Tg-A for predicting stimulated Tg+ of 1 ng/mL were 0.3, 0.2, and 0.2 ng/mL, respectively. The sensitivity, specificity, and accuracy of suppressed Tg+ were 67%, 100%, and 90%, respectively; those of suppressed Tg-K were 83%, 90%, and 88%; those of suppressed Tg-A were 96%, 82%, and 87%, respectively. The positive predictive and negative predictive values of Tg+ were 100% and 87%, respectively; those of Tg-K were 79% and 92%; and those of Tg-A were 73% and 98%.

CONCLUSION

We could not clearly demonstrate which kit had better diagnostic performance after comparison of first-generation Tg measurements with Tg-IMA measurements. Also, there were kit-to-kit variations between Tg-IMA kits. Suppressed Tg measured by Tg-IMA was insufficient to completely substitute for a stimulated Tg measurement.

Transfibular ankle arthrodesis using burring, curettage, multiple drilling, and fixation with two retrograde screws through a single lateral incision

PURPOSE

To review the outcome of 23 ankle arthrodeses using burring, curettage, multiple drilling, and fixation with 2 retrograde screws through a single lateral incision.

METHODS

Records of 22 consecutive patients aged 39 to 79 (mean, 62.4) years who underwent 23 ankle arthrodeses for end-stage ankle arthritis were reviewed. Through a single lateral incision, articular cartilage was removed using burring and curettage, and multiple holes were drilled using a Kirschner wire, followed by fixation with 2 retrograde screws. The resected distal fibula was fixed to the distal part of the talus and tibia. The position of the ankle and subtalar joint arthrosis was assessed by 2 orthopaedic specialists. Pre- and post-operative American Orthopaedic Foot and Ankle Society (AOFAS) scores were evaluated.

RESULTS

The mean operating time was 122 minutes. The mean follow-up period was 41 months. The mean postoperative ankle alignment was suboptimal: 2.7º varus, 6.7º plantar flexion, and 2.9º internal rotation. The mean AOFAS score improved from 30 to 71 (p<0.01). The postoperative varus ankle alignment was not associated with the AOFAS score (r= -0.13, p=0.569). Of the 23 cases, one was nonunion and 22 achieved bone union after a mean of 5.4 (range, 2-16) months; 3 of them were delayed union. Despite bone union, 7 patients complained of persistent pain; 4 of them had progressive arthrosis of the adjacent subtalar joints (n=2) or subtalar and talonavicular joints (n=2).

CONCLUSION

Ankle arthrodesis using burring, curettage, multiple drilling, and fixation with 2 retrograde screws achieved a high union rate and acceptable functional score without serious complications.

A competitive quantitative polymerase chain reaction method for characterizing the population dynamics during kimchi fermentation

The aim of this study was to develop a competitive quantitative-PCR (CQ-PCR) method for rapid analysis of the population dynamics of lactic acid bacteria (LAB) in kimchi. For this, whole chromosome sequences of Leuconostoc mesenteroides, Lactobacillus plantarum, and Lb. brevis were compared and species-specific PCR primers targeting dextransucrase, 16S rRNA, and surface layer protein D (SlpD) genes, respectively, were constructed. The tested strains were quantified both in medium and kimchi by CQ-PCR and the results were compared with the data obtained using a conventional plate-counting method. As a result, the three species were successfully detected and quantified by the indicated primer sets. Our results show that the CQ-PCR method targeting species-specific genes is suitable for rapid estimation of LAB population to be used in the food fermentation industry.

A novel mutation of the succinate dehydrogenase B gene in a Korean family with pheochromocytoma

Pheochromocytoma is a tumor that originates from the adrenal cortex and sympathetic chains. Most pheochromocytomas are sporadic, whereas others occur as hereditary syndromes. Familial pheochromocytoma has been frequently found in association with various mutations in genes of the succinate dehydrogenase family. A 21-year-old Korean male presented with recurrent chest tightness, severe headache, and hypertension. He was diagnosed as pheochromocytoma based on a 24-hour urine test, abdominal computed tomography, and (131)I-MIBG scintigraphy. Genomic DNA was extracted from the patient's whole blood. Primers covering all the coding regions and flanking introns of succinate dehydrogenase (SDH) B, C and D genes were designed and synthesized, and a DNA sequence analysis was performed using the polymerase chain reaction. Direct sequencing of the SDHB gene revealed a deletion of nucleotide 757 (thymidine) in exon 7. This thymidine deletion caused a shift in the reading frame that created a downstream stop codon and a truncated product (p.Cys253ValfsX5). Although the patient had no family history of pheochromocytoma, his father had the same mutation. We report a novel SDHB gene mutation from a Korean family with pheochromocytoma. This is the first report of pheochromocytoma with a confirmed SDHB germline mutation in Korea.

[Standardization of terminology in laboratory medicine I]

BACKGROUND

Standardization of medical terminology is essential for data transmission between health-care institutions or clinical laboratories and for maximizing the benefits of information technology. Purpose of our study was to standardize the medical terms used in the clinical laboratory, such as test names, units, terms used in result descriptions, etc. During the first year of the study, we developed a standard database of concept names for laboratory terms, which covered the terms used in government health care centers, their branch offices, and primary health care units.

METHODS

Laboratory terms were collected from the electronic data interchange (EDI) codes from National Health Insurance Corporation (NHIC), Logical Observation Identifier Names and Codes (LOINC) database, community health centers and their branch offices, and clinical laboratories of representative university medical centers. For standard expression, we referred to the English-Korean/ Korean-English medical dictionary of Korean Medical Association and the rules for foreign language translation. Programs for mapping between LOINC DB and EDI code and for translating English to Korean were developed.

RESULTS

A Korean standard laboratory terminology database containing six axial concept names such as components, property, time aspect, system (specimen), scale type, and method type was established for 7,508 test observations. Short names and a mapping table for EDI codes and Unified Medical Language System (UMLS) were added. Synonym tables for concept names, words used in the database, and six axial terms were prepared to make it easier to find the standard terminology with common terms used in the field of laboratory medicine.

CONCLUSIONS

Here we report for the first time a Korean standard laboratory terminology database for test names, result description terms, result units covering most laboratory tests in primary healthcare centers.

Standardization of terminology in laboratory medicine II

Standardization of medical terminology is essential in data transmission between health care institutes and in maximizing the benefits of information technology. The purpose of this study was to standardize medical terms for laboratory observations. During the second year of the study, a standard database of concept names for laboratory terms that covered those used in tertiary health care institutes and reference laboratories was developed. The laboratory terms in the Logical Observation Identifier Names and Codes (LOINC) database were adopted and matched with the electronic data interchange (EDI) codes in Korea. A public hearing and a workshop for clinical pathologists were held to collect the opinions of experts. The Korean standard laboratory terminology database containing six axial concept names, components, property, time aspect, system (specimen), scale type, and method type, was established for 29,340 test observations. Short names and mapping tables for EDI codes and UMLS were added. Synonym tables were prepared to help match concept names to common terms used in the fields. We herein described the Korean standard laboratory terminology database for test names, result description terms, and result units encompassing most of the laboratory tests in Korea.

[Development of Secondary Order System for Laboratory Tests without Additional Blood Sampling.]

BACKGROUND

Additional tests ordered by doctors after checking abnormal routine test results for inpatients are usually delayed for one day or more, which in turn delays diagnostic and therapeutic procedures and prolongs length of stay (LOS) for the patients. We at Department of Laboratory Medicine, Asan Medical Center (AMC), established a "secondary order system for laboratory tests without additional blood sampling" to improve the conventional reflexive tests.

METHODS

Oracle 8.0 (Oracle Co., Belmont, CA, USA) was used for data base software and Powerbuilder (Powersoft, Burlington, UK) for client development tool. Specimens subjected to "reflexive tests by doctors without additional blood sampling" were SST tubes for routine chemistry and EDTA for routine hematology requested in the morning of additional requests of the laboratory tests.

RESULTS

Programs of registration and request for "reflexive tests by doctors without additional blood sampling" and bar code printing were developed for clinicians to check the routine test results and to order additional tests, if necessary, and for laboratory to perform the requested tests using the same samples used for routine chemistry and hematology tests in the morning. Additionally requested tests were done by finding the SST and EDTA samples, putting newly printed bar code, and processing them as usual. In February 2004, right after introducing reflexive tests by doctors without additional blood sampling, 75 additional requests were made for 50 patients, but they increased gradually up to 1,020 tests for 698 patients in December 2004. In 2005, the monthly average number of tests was 1,035 for 742 patients.

CONCLUSIONS

The reflexive tests by doctors without additional blood sampling developed at AMC helped establish a rapid reporting of test results, which in turn reduced LOS related to laboratory. It also increased patient satisfactory indices by reducing repeated blood sampling and would also contribute to the financial health of the hospital.

Evaluation of fixed quality control range of bayer rapidpoint 400 blood gas and electrolyte analyzer with six sigma metrics

BACKGROUND

Bayer Rapidpoint 400 analyzer for point of care testing (POCT) uses fixed quality control (QC) range even when the lot number of a cartridge for quality control changes. To evaluate the fixed QC range recommended by the manufacturer, we analyzed internal QC data of 9 analyzers with Six Sigma metrics.

MATERIALS AND METHODS

We investigated QC data of 9 analyzers over 5 months from May to September, 2004 for 8 parameters (pH, pCO(2), pO(2), Na(+), K(+), iCa(++), Cl(-), and glucose). One hundred eighty six groups of QC data were analyzed with capability index (C(p)=total allowable error (TEa)/3 standard deviation (SD)) and capability index considering bias (C(pk),=(TEa-bias)/3 SD). Acceptability was evaluated with criteria of 1.33 C(pk), 4 sigma level or quality criteria of the Clinical Laboratory Improvement Amendments of 1988 (CLIA'88).

RESULTS

In 80.7% (150 of 186 groups), both C(p) and C(pk) were at or above 1.33, which indicated that the use of fixed QC range was adequate. In 19.3% (36 of 186 groups), C(pk) was below 1.33, which indicated the inadequacy of fixed QC range. Among them 14.5% (27 of 186 groups) showed C(p) below 1.33, indicating that the errors had a random factor and 4.8% (9 of 186 groups) had C(p) at or above 1.33, indicating that the errors had a systematic factor.

CONCLUSIONS

The quality criteria mandated by CLIA '88 was satisfied in about 80% of study groups using fixed QC ranges, but in about 20%, more strict instrument maintenance and specimen handling by operators, and quality improvement of QC materials by manufacturer was required.

Serum high-sensitivity C-reactive protein is not increased in patients with IgA nephropathy

BACKGROUND/AIMS

The development of renal injury in glomerulonephritis (GN) has been related to systemic inflammatory mediators. We investigated whether serum high-sensitivity C-reactive protein (hs-CRP) is a marker reflecting the inflammatory pathogenesis of primary GN.

METHODS

We compared serum hs-CRP levels in 192 patients with IgA nephropathy (IgAN), 43 patients with membranous nephropathy (MN), and 25 patients with minimal change disease (MCD) undergoing kidney biopsy and 638 matched controls.

RESULTS

There were no differences in hs-CRP levels between controls (median 0.08 mg/dl; range 0.03-1.87 mg/dl) and patients with IgAN (0.08 mg/dl; 0.03-3.13 mg/dl), MN (0.07 mg/dl; 0.03-0.99 mg/dl) or MCD (0.08 mg/dl; 0.03-1.75 mg/dl). In patients with IgAN, hs-CRP levels did not differ according to Haas' pathological subclasses or subsequent renal outcomes. In the IgAN group, hs-CRP showed positive correlations with IgA, uric acid, systolic blood pressure, BMI and age. Hs-CRP level was significantly higher in male than in female IgAN patients. Serum IgA concentration was the strongest independent correlate with hs-CRP levels, and gender and BMI were also independently associated with hs-CRP. There were no correlations between hs-CRP and markers of disease activity.

CONCLUSION

It is likely that hs-CRP does not closely reflect inflammatory pathogenesis in patients with IgAN, MN and MCD.

Effects of alpha-lipoic acid on the plasma levels of asymmetric dimethylarginine in diabetic end-stage renal disease patients on hemodialysis: a pilot study

BACKGROUND/AIM

Endothelial dysfunction due to reduced nitric oxide (NO) availability precedes the development of atherosclerosis. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO synthase, is not only a cause of endothelial dysfunction, but also a predictor of the cardiovascular outcome in end-stage renal disease (ESRD) patients on hemodialysis (HD). Alpha-lipoic acid (ALA), a strong antioxidant, increases NO-mediated vasodilation in diabetic patients. We investigated whether ALA could decrease the plasma level of ADMA in diabetic ESRD patients on HD.

METHODS

Fifty patients undergoing HD three times per week were randomized to a treatment group receiving ALA 600 mg/day for 12 weeks or a control group. We measured the plasma levels of cholesterol, albumin, high-sensitivity C-reactive protein, oxidized low-density lipoprotein, hemoglobin A1c, and ADMA in both groups at baseline and at 12 weeks.

RESULTS

In the control group, the levels of total cholesterol, serum albumin, high-sensitivity C-reactive protein, oxidized low-density lipoprotein, hemoglobin A1c, and ADMA did not change. In the treatment group, the plasma levels of ADMA decreased significantly from a median of 1.68 (range 0.45-3.78) microM to a median of 1.31 (range 0.25-3.19) microM (p = 0.001).

CONCLUSION

Considering that ADMA is an independent risk factor for cardiovascular outcome in ESRD patients, ALA may have the potential of a beneficial effect in them, in part by decreasing the plasma level of ADMA.

Effects of celecoxib on high-sensitivity C-reactive protein in chronic peritoneal dialysis patients

To evaluate the effects of celecoxib, a cyclooxygenase-2 inhibitor, on the level of high-sensitivity C-reactive protein (hs-CRP), D-dimer, von Willebrand factor (vWF) and troponin-T, 46 chronic peritoneal dialysis (CPD) patients with hs-CRP equal or greater than 0.25 mg/dL were randomized to the treatment group who took 200 mg of celecoxib daily for 4 weeks or to the control group who did not take the medication. The levels of hs-CRP, albumin, D-dimer, vWF and troponin-T were measured at baseline and at 4 weeks of the study. Baseline values of all the parameters were not significantly different between the two groups. In the control group, the levels of hs-CRP, albumin, D-dimer, vWF and troponin-T did not change. In the treatment group, administration of celecoxib for 4 weeks significantly reduced hs-CRP from median 0.77 (range 0.25-7.08) to 0.39 mg/dL (range 0.11-5.22, p<0.05). The levels of albumin, D-dimer, vWF and troponin-T levels were not affected by the administration of celecoxib. These results showed that celecoxib had an antiinflammatory effect in usual dosage in CPD patients.

Discrepancy of interleukin-6 levels between end-stage renal disease patients and patients with acute-phase response with increased lipoprotein(a) concentrations

Though the concentration of serum lipoprotein(a) [Lp(a)] is mostly determined by genetic factors, secondary factors such as acute-phase response (APR) and end-stage renal disease (ESRD) also contribute to its increase. Lp(a) is known to be one of the acute-phase reactants and interleukin-6 (IL-6) is the key cytokine in the hepatic synthesis of acute-phase proteins. The serum concentrations of Lp(a) and IL-6 were measured in patients with APR and in patients with ESRD to investigate the relationship between Lp(a) and IL-6. A total of 180 patients were selected for the study: 60 patients were normal controls, 60 were patients with renal disease who had been on hemodialysis for more than 6 months [C-reactive protein (CRP)<4.0 mg/L], and 60 were APR patients who had a erythrocyte sedimentation rate (ESR) of over 50 mm/h. The three groups were age- and sex matched. The serum concentrations of Lp(a) and IL-6 were measured by ELISA. The serum concentrations of Lp(a) [median (interquartile range)] in normal controls, ESRD patients, and APR patients were 0.222 (0.103-0.364) g/L, 0.511 (0.308-0.755) g/L, and 0.546 (0.234-0.747) g/L, respectively; those of IL-6 were 1.0 (0.7-1.3) pg/mL, 2.1 (1.4-3.3) pg/mL, and 26.2 (15.2-35.6) pg/mL. The concentration of IL-6, which increases Lp(a) synthesis, was much lower in ESRD patients than in APR patients (p<0.001). However, there were no significant differences in Lp(a) concentration between the two groups (p=0.88). In APR patients, the increase in Lp(a) synthesis seems to play a significant role in the increase in blood Lp(a), but there might be different mechanisms that regulate the increment of serum Lp(a) concentrations in ESRD patients other than synthesis of Lp(a).

Effects ofGinkgo biloba on haemostatic factors and inflammation in chronic peritoneal dialysis patients

Ginkgo biloba extract decreased plasma D-dimer concentration, a marker of intravascular coagulation, in chronic peritoneal dialysis patients. Blood levels of fibrinogen, von Willebrand factor, hs-CRP, albumin and liver enzyme levels were not significantly changed. No bleeding episode was reported. These results suggest that Ginkgo biloba extract was effective in partially reversing the thrombogenic coagulation profile without increasing the risk of bleeding.

Association between HaeIII polymorphism of scavenger receptor class B type I gene and plasma HDL-cholesterol concentration

BACKGROUND

Evidence has recently been found for significant associations between genetic variation within the scavenger receptor class B type I gene (SR-BI), plasma lipids and anthropometric measurements in healthy Caucasians. The present case-control study was conducted to determine whether there is an association between three polymorphisms identified by the restriction endonucleases HaeIII, AluI and ApaI of SR-BI and coronary artery disease (CAD) in Korean subjects.

METHODS

DNA was extracted from 137 subjects with CAD and 124 age-matched controls; it was amplified using the polymerase chain reaction. Individual alleles at each of the three polymorphic sites were identified by digestion with the appropriate restriction enzyme.

RESULTS

Only a single allele was identified at the AluI and ApaI polymorphic sites. The frequency of the common (+) allele at the HaeIII polymorphic site was higher in CAD patients than in the controls (P = 0.001). The concentrations of plasma HDL-cholesterol and apolipoprotein AI also varied significantly among HaeIII genotypes in the CAD patients. The common (+) allele of the HaeIII polymorphism was associated with a lower body mass index in female controls.

CONCLUSIONS

Allele frequencies of the AluI and ApaI polymorphisms in this study were different to those in a Caucasian population studied previously, suggesting a difference in the genetic background. Further comparative studies of SR-BI polymorphism in other racial or ethnic groups should therefore prove to be of value.

Effects of simvastatin on high-sensitivity C-reactive protein and serum albumin in hemodialysis patients

A 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor is recommended in hemodialysis (HD) patients with hypercholesterolemia to improve their lipid profiles. We evaluated effects of simvastatin on markers for inflammation, oxidative stress, and coagulation in HD patients. Sixty-two maintenance HD patients with serum cholesterol levels of 200 mg/dL or greater were randomly assigned to the treatment group (n = 31; 8 men, 23 women; age, 63 +/- 11 years) and administered simvastatin, 20 mg/d, for 8 weeks or to the control group (n = 31; 10 men, 21 women; age, 60 +/- 12 years). We measured cholesterol, albumin, high-sensitivity C-reactive protein (hs-CRP), malondialdehyde (MDA; an index of lipid peroxidation), and D-dimer (a marker of intravascular coagulation) in blood at baseline and again at 8 weeks. Fifty-eight of 62 patients completed the study. In the control group, total cholesterol, serum albumin, hs-CRP, MDA, and D-dimer levels did not change. In the treatment group, simvastatin administration for 8 weeks significantly reduced total cholesterol levels from 232 +/- 25 to 165 +/- 39 mg/dL (P < 0.001) and hs-CRP levels from a median of 0.23 mg/dL (range, 0.05 to 1.63 mg/dL) to 0.12 mg/dL (range, <0.006 to 1.45 mg/dL; P < 0.01), whereas it increased serum albumin levels from 3.4 +/- 0.3 to 3.6 +/- 0.4 g/dL (P < 0.001). Administration of simvastatin did not affect MDA and D-dimer levels. These results suggest that in addition to the lipid-lowering effect, simvastatin had an antiinflammatory effect in HD patients. Considering that atherosclerosis is inflammation of the vascular wall, simvastatin may have a beneficial effect on cardiovascular disease, in part because it alleviates inflammation.

Persistent elevation of C-reactive protein and ischemic heart disease in patients with continuous ambulatory peritoneal dialysis

We evaluated the association between a persistent elevation of C-reactive protein (CRP) level and the presence or severity of ischemic heart disease (IHD) in patients with continuous ambulatory peritoneal dialysis (CAPD). Seventy-three patients, who were over 40 years old, underwent dipyridamole thallium single photon emission computed tomography (SPECT), and followed-up for more than 1 year were enrolled. We measured stored plasma for CRP every 3 months. Elevation of CRP was defined as greater than or equal to 5 mg/L and persistent elevation of CRP as elevated CRP levels that lasted longer than 6 months. Serum albumin, cholesterol, lipoprotein(a), and plasma fibrinogen were measured at 3 months after the start of CAPD. Twenty-six patients showed an elevation of CRP for more than 6 months during the follow-up period. Twenty-eight patients showed positive findings on thallium SPECT. Coronary angiography showed significant stenosis (narrowing of the diameter more than 50%) in 23 of the 25 patients studied. Seventeen (65%) of 26 patients who had an elevated CRP level for longer than 6 months had positive thallium SPECT. The presence of diabetes, albumin, fibrinogen, and the presence of a persistent elevation of CRP were different between the patients with positive (n = 28) or negative thallium SPECT (n = 45). A multivariate logistic regression analysis showed that a persistent elevation of CRP is the only predictor of positive thallium SPECT (P = 0.002). There was a tendency of association, although it was not statistically significant, between the persistence of CRP elevation and the severity of IHD (P = 0.066). Three of 9 patients who had a persistent elevation of CRP and a negative thallium SPECT had a history of cerebral infarction or peripheral vascular disease. Therefore, 77% (20/26) of an elevated CRP level that lasted longer than 6 months can be explained by the presence of IHD or other atherosclerotic vascular disease. In conclusion, a persistent elevation of CRP level in patients with CAPD was strongly associated with IHD. For patients who have a persistent elevation of CRP without an apparent cause, we recommend a workup for IHD or other atherosclerotic cardiovascular disease.

Effects of hormonal replacement therapy on oxidative stress and total antioxidant capacity in postmenopausal hemodialysis patients

BACKGROUND

Oxidative stress is known to be implicated in the pathogenesis of atherosclerotic cardiovascular disease. Many studies have demonstrated that hormone replacement therapy (HRT) has beneficial effects on oxidation injury in postmenopausal women with normal renal function. In this study, we examined the effects of HRT on plasma malondialdehyde (MDA) level and total antioxidant capacity (TAC) in postmenopausal hemodialysis women.

METHODS

We randomly assigned 70 postmenopausal women on maintenance hemodialysis into either a HRT group or a control group. Oral conjugated estrogen (0.625 mg) combined with medroxyprogesterone acetate (2.5 mg) was given daily for 12 weeks in HRT group. Plasma MDA, TAC, albumin, uric acid and C-reactive protein (CRP) were measured before, 4 and 12 weeks after the start of medication in the HRT group. In the control group, the same parameters were measured without HRT.

RESULTS

There was no difference in baseline values between the two groups. In the control group (n = 32), all these parameters showed no change at 4 and 12 weeks. HRT decreased MDA from 1.32 (0.55-1.88) microM to 1.08 (0.44-1.50) microM (p < 0.001) at 4 weeks and to 1.11 (0.50-1.37) microM (p < 0.001) at 12 weeks (n = 33). TAC was not changed at 4 weeks, however, it decreased from 1.59 (1.27-2.00) mM to 1.45 (1.08-1.65) mM (p < 0.05) at 12 weeks. The albumin, uric acid and CRP levels were not changed significantly after HRT.

CONCLUSIONS

These results suggest that HRT has a favorable effect on oxidative stress in postmenopausal women with ESRD as in the general population.

Genetic variations of the paraoxonase gene in patients with coronary artery disease

OBJECTIVES

Paraoxonase (PON) plays an important role in preventing low density lipoprotein (LDL) oxidation and thus may be involved in protection against atherosclerosis. Several studies have suggested that genetic variations of the PON gene are associated with plasma HDL levels and coronary artery disease (CAD). This study was conducted to elucidate the association between three polymorphisms of the PON1 and PON2 genes and Korean patients with CAD.

DESIGN AND METHODS

One hundred ninety-one patients with CAD and 113 age-matched normal controls were examined by polymerase chain reaction (PCR). The PCR products were analyzed for PON polymorphisms by restriction enzyme digestion.

RESULTS

There was linkage disequilibria between each polymorphism pair in the CAD and control groups. The Hsp92II polymorphism at codon 54 of the PON1 gene was positively associated with HDL-cholesterol levels in the control group (p = 0.02). An association between the AlwI polymorphism and HDL-cholesterol level appeared statistically significant in women of the normal group (p = 0.04). In addition, the DdeI and AlwI polymorphisms were positively associated with HDL (p = 0.02) and LDL (p = 0.03) levels in men of the CAD group, respectively.

CONCLUSIONS

Our study suggested a gene-gene interaction between the PON1 and PON2 polymorphisms for CAD risk. However, we could not exclude the possibility that these polymorphisms may have linkage disequilibrium with a tightly linked PON3 locus or significant atherosclerotic alleles of nearby genes. Family studies may, therefore, help to confirm the role of the PON polymorphism for CAD risk.

Apolipoprotein E polymorphism and serum lipoprotein(a) concentrations in a Korean male population

The purpose of this study was to investigate the effect of apolipoprotein E polymorphism on lipoprotein(a) metabolism by comparing serum lipoprotein(a) concentration with apolipoprotein E genotype in a Korean male population whose high molecular weight (HMW) lipoprotein(a) frequency was 95-98%. Serum lipoprotein(a), total cholesterol, triglyceride and high-density lipoprotein-cholesterol concentrations were measured and the apolipoprotein E genotype determined in 1189 healthy Korean males. The medians of serum lipoprotein(a) concentration in the apo E 2/3 group (0.105 g/L) and the apo E 3/4 group (0-116 g/L) were significantly lower than that in the apo E 3/3 group (0.155 g/L; P < 0.001). The medians of serum triglyceride were 1.497 mmol/L in the apo E 2/3 group, 1.356 mmol/L in the apo E 3/4 group, and 1.452 mmol/L in the apo E 3/3 group (P<0.05). With the significant difference in the serum lipoprotein(a) concentration in Korean males according to apolipoprotein E genotype, and with the negative correlation between serum triglyceride concentration and serum lipoprotein(a) concentration, it is suggested that apolipoprotein E polymorphism and serum triglyceride participate in the metabolism of lipoprotein(a) with HMW.

Effects of hormonal replacement therapy on lipid and haemostatic factors in post-menopausal ESRD patients

BACKGROUND

Hormone replacement therapy (HRT) has been known to have beneficial effects on various atherosclerotic parameters in the general population of post-menopausal women. To evaluate the effects of HRT on those factors in end-stage renal disease (ESRD) patients, we evaluated the changes of lipid profile, coagulation and fibrinolysis markers, and plasma homocysteine levels after treatment.

METHODS

Sixty-five post-menopausal women on maintenance haemodialysis were randomly assigned to either an HRT group (n=33) or a control group (n=32). Median age (range) and duration of haemodialysis (range) were 57 years (40-73) and 42 months (6-150) in the HRT group and 61 years (44-78) and 54 months (8-174) in the control group respectively. Oral conjugated oestrogen (0.625 mg) combined with medroxyprogesterone acetate (2.5 mg) was given daily for 12 weeks to the HRT group. Total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), lipoprotein (a) (Lp(a)), fibrinogen, plasminogen activator type 1 antigen (PAI-1), tissue plasminogen antigen (t-PA), von Willebrand factor (vWF), and plasma total homocysteine (tHcy) were measured before and 12 weeks after the start of the study in both groups.

RESULTS

There was no difference in baseline values between the control and HRT groups. At 12 weeks, HRT increased HDL-C by 12% (P:<0.01) and TG by 20% (P:<0. 01). HRT decreased LDL-C by 9% (P:<0.01), and Lp(a) by 36% (P:<0.01). PAI-1 and t-PA concentrations were also reduced by 21% (P:<0.01) and 9% (P:<0.05) respectively. The mean values of TC, fibrinogen, vWF, and tHcy levels did not change significantly after HRT.

CONCLUSIONS

The above results suggest that HRT has favourable effects on atherosclerosis risk parameters in post-menopausal women with ESRD as in the general population of post-menopausal women.

Atherothrombotic middle cerebral artery territory infarction: topographic diversity with common occurrence of concomitant small cortical and subcortical infarcts

BACKGROUND AND PURPOSE

MRI has superior capabilities for the detection of cerebral infarcts compared with CT. CT was used to locate infarcts in most previous studies of atherothrombotic middle cerebral artery (MCA) territory infarcts. Thus, there was a possibility of missing concomitant small infarcts. More accurate identification of topographic lesions in MCA territory with MRI may help to establish the pathogenesis of stroke. The present study determines topographic patterns, distribution of vascular lesions, and probable mechanisms.

METHODS

Forty-two patients with MCA territory infarcts on routine MRI and no major cause of cardioembolism were studied with conventional angiography or MR angiography.

RESULTS

The topographic patterns seen on MRI were subdivided into 4 groups: cortical border-zone infarcts (n=6), pial territory infarcts without insular infarct (n=3), pial territory infarcts with insular infarct (n=14), and large subcortical infarcts (n=19). Of 6 patients with cortical border-zone infarcts, 4 had concomitant small cortical or subcortical multiple lesions. Angiography showed intrinsic MCA disease in 4 patients. Of 3 patients with pial territory infarcts without insular infarct, 2 also had small multiple centrum ovale lesions. All had intrinsic MCA disease. Pial territory infarcts with partial or whole insular lesions were present in 10 and 4 patients, respectively. Five patients had additional multiple cortical or subcortical lesions. Ten patients had intrinsic MCA disease. Of the 19 patients with large subcortical infarcts, 12 had centrum ovale infarcts, and 4 had both basal ganglia and centrum ovale lesions. Ten had concomitant small cortical or subcortical lesions. Six patients had intrinsic MCA disease.

CONCLUSIONS

Similar vascular lesions induce different topographic patterns in MCA territory infarction, which are related to individual vascular variability, degree of primary and secondary collateralization, and pathogenesis of infarcts. Our study indicates that concomitant small cortical or subcortical lesions are also commonly associated findings in diverse patterns of MCA territory infarction, which can mostly be explained by probable embolic mechanism.

In vivo antioxidant effect of green tea

OBJECTIVE

The object of this study was to investigate the in vivo antioxidant effect of green tea and dosage effect of green tea on antioxidant effect.

DESIGN

We tested 10 healthy subjects (aged 23-25 y, five women and five men) with overnight fasting. The total antioxidant capacity of plasma was measured at baseline and 60 min and 120 min after ingestion of 150 ml green tea. Green tea was prepared by infusing 2.5 g of dried green tea leaves for 2 min at 80 degrees C in 150 ml of water. In the second week, they took 300 ml of tea (5.0 g of green tea leaves) and, in the third week, 450 ml of tea (7.5 g of green tea leaves). The total antioxidant capacities of plasma were determined with a Total Antioxidant Kit (Randox Laboratories Ltd, UK) using a Cobas Mira analyser (Roche Diagnostic Systems Inc., Switzerland). The mean intra-assay coefficient of variation was 1.2%.

RESULTS

The total antioxidant capacity of plasma increased by 1.1% at 60 min and 2.1% at 120 min over baseline value in subjects consuming 150 ml of green tea, which was statistically not significant. However, total antioxidant capacity of plasma after consuming 300 ml of green tea showed a significant increase of 7.0% after 60 min and 6.2% after 120 min (P<0.0001), and after consuming 450 ml 12.0% after 60 min and 12.7% after 120 min over baseline value (P<0.0001).

CONCLUSIONS

Total antioxidant capacity of plasma was significantly increased after taking green tea in amounts of 300 and 450 ml. A positive increment according to green tea dosage was also observed.

SPONSORSHIP

This work was funded by the Pacific Corporation (Korea).

Reduced oxidative stress in hypoalbuminemic CAPD patients

OBJECTIVE

Albumin is one of the plasma antioxidants. The higher incidence of cardiovascular disease in dialysis patients with hypoalbuminemia may be related to decreased antioxidant capacity resulting from low serum albumin. We evaluated malondialdehyde (MDA), a marker of oxidative stress, and total antioxidant capacity (TAC) in relation to serum albumin in continuous ambulatory peritoneal dialysis (CAPD) patients.

PATIENTS AND METHODS

In this cross-sectional study, we measured MDA, TAC, albumin, uric acid (another important plasma antioxidant), prealbumin, and C-reactive protein (CRP) in the blood of 66 CAPD patients and 30 normal controls.Twenty-two CAPD patients with albumin less than or equal to 3.5 g/dL were divided into two groups: In the experimental group (n = 11), MDA,TAC, and CRP were measured before and after repeated infusion of 20% albumin 100 mL daily for 7 days. In the control group (n = 11), the same parameters were measured without albumin infusion.

RESULTS

CAPD patients had lower albumin and higher MDA,TAC, and uric acid than normal controls. There were positive correlations between albumin and TAC or uric acid in CAPD patients. Contrary to our expectation, there was also positive correlation between albumin and MDA in CAPD patients (r = 0.37, p = 0.004). MDA showed a positive correlation with TAC. Uric acid was correlated with TAC. It did not, however, show correlation with MDA. Log CRP was negatively correlated with albumin, but did not show correlation with MDA or TAC. Prealbumin was correlated with MDA, TAC, albumin, and uric acid. Serum albumin in the experimental group increased from 2.5+/-0.3 g/dL to 3.6+/-0.2 g/dL (p < 0.001) at the end of repeated infusions. No changes were seen in MDA, TAC, and CRP in either group.

CONCLUSIONS

The present study suggests that lipid peroxidation is increased in CAPD patients and that this is not due to weakening of antioxidant defenses of plasma. Increased TAC was mainly caused by a higher level of uric acid. Reduced, rather than increased, MDA in hypoalbuminemic patients and lack of effects of albumin infusion on levels of MDA suggest that the frequent occurrence of cardiovascular disease in dialysis patients with hypoalbuminemia is not due to the decrease in antioxidant capacity resulting from low serum albumin.

Distribution of haptoglobin phenotypes in a Korean population, using the semi-automated PhastSystem

We have established a new phenotyping method for haptoglobin, based on sodium dodecyl sulphate-polyacrylamide gel electrophoresis using the PhastSystem (Pharmacia Biotech, Uppsala, Sweden), followed by immunoblotting for detection. We measured haptoglobin concentrations and determined the haptoglobin phenotypes of 316 healthy Koreans using this method: 31 (9.8%) were of Hp 1-1 type, 140 (44.3%) of Hp 2-1 type and 145 (45.9%) of Hp 2-2 type. The haptoglobin allele frequencies were calculated to be 0.32 for Hp1 and 0.68 for Hp2. We were able to visualize up to 12 bands from the human Hp 2-2 polymeric series, with molecular weights in the range 171.9 x 10(3) to 802.2 x 10(3). The reference range of serum haptoglobin concentrations obtained by the IFCC (International Federation of Clinical Chemistry) standard method was 0.27-2.14 g/L. The serum haptoglobin concentration in Koreans was similar to that of Caucasians, but the Hp1 allele frequency was lower in Koreans. Our method could be used in clinical laboratories as a simple and practical method of haptoglobin phenotyping. In addition, the Hp 2-2 polymeric series could be used as high molecular weight standards.

Atherothrombotic cerebellar infarction: vascular lesion-MRI correlation of 31 cases

BACKGROUND AND PURPOSE

Correlation of MRI findings with atherosclerotic vascular lesions has rarely been attempted in patients with cerebellar infarction. The aim of this study was to correlate the MRI lesions with the vascular lesions seen on conventional cerebral angiography in cerebellar infarction.

METHODS

The subjects included 31 patients with cerebellar infarcts who underwent both MRI and conventional cerebral angiography. We analyzed the risk factors, clinical findings, imaging study, and angiography results. We attempted to correlate MRI lesions with the vascular lesions shown in the angiograms.

RESULTS

The vascular lesions seen on angiograms were subdivided into 3 groups: large-artery disease (n=22), in situ branch artery disease (n=6), and no angiographic disease with hypertension (n=3). The proximal segment (V1) lesions of vertebral artery were the most common angiographic features in patients with large-artery disease in which stroke most commonly involved the posterior inferior cerebellar artery (PICA) cerebellum. The V1 lesions with coexistent occlusive lesions of the intracranial vertebral and basilar arteries were correlated with cerebellar infarcts, which had no predilection for certain cerebellar territory. The intracranial occlusive disease without V1 lesion was usually correlated with small cerebellar lesions in PICA and superior cerebellar artery (SCA) cerebellum. The subclavian artery or brachiocephalic trunk lesion was associated with small cerebellar infarcts. The in situ branch artery disease was correlated with the PICA cerebellum lesions, which were territorial or nonterritorial infarct. No angiographic disease with hypertension was associated with small-sized cerebellar infarcts within the SCA, anterior inferior cerebellar artery, or SCA cerebellum.

CONCLUSIONS

Our study indicates that the topographic heterogeneity of cerebellar infarcts are correlated with diverse angiographic findings. The result that large-artery disease, in which nonterritorial infarcts are more common than territorial infarcts, is more prevalent than in situ branch artery disease or small-artery disease, suggest that even a small cerebellar infarct can be a clue to the presence of large-artery disease.

The risk groups for coronary heart disease in Koreans. Assessment by distribution of serum lipid concentrations

Coronary heart disease is the most severe form of disease caused by atherosclerosis; and there is a strong relationship between serum lipid concentrations and atherosclerosis. By decade of life, means, standard deviations and selected percentiles were calculated according to sex for serum concentrations of total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglyceride in 69,563 Koreans. The prevalence of dyslipoproteinemias which were related to high risk of coronary heart disease were assessed. The mean concentrations of serum total cholesterol and LDL-C in the Korean population were 5.02 mmol/l and 3.00 mmol/l. The 75th and 90th percentile concentrations of total cholesterol were 5.59 mmol/l and 6.24 mmol/l. The mean concentrations of serum triglyceride and HDL-C were 1.58 mmol/l and 1.30 mmol/l. The hyperlipoproteinemia type IV (4.8%) was the most frequent, followed by Type IIa (4.6%), hypoalphalipoproteinemia (3.3%), and type IIb (0.2%). According to the National Cholesterol Education Program Adult Treatment Panel II, 4.1% of Korean adults needed the initial drug therapy and 10.8% the initial dietary therapy for hypercholesterolemia. The age and sex-specific treatment guidelines for hypercholesterolemia would make it possible that early intervention could be applied to atherosclerosis in Korean adults.

No relationship between serum lipoprotein(a) and albumin concentrations in patients with acute phase response

The aim of this study was to investigate the relationship between lipoprotein(a) [Lp(a)] and albumin concentrations in the serum of patients with acute phase response (APR). We have compared the Lp(a) concentrations and apolipoprotein [apo(a)] phenotypes of 40 controls with those of 40 APR patients with normoalbuminaemia and 40 APR patients with hypoalbuminaemia. We have also compared concentrations of haptoglobin (Hp) and alpha 1-antitrypsin (AAT) containing a high sialic acid content, similar to Lp(a). The mean serum Lp(a) concentration (SD) of the 40 controls was 0.190 (0.142) g/L. The mean serum Lp(a) concentration was 0.358 (0.257) g/L (P < 0.001) in 80 APR patients. However, there was no difference in serum Lp(a) concentrations between the APR patients with hypoalbuminaemia [0.353 (0.268) g/L] and the APR patients with normoalbuminaemia [0.362 (0.249) g/L]. No significant difference was found in the distributions of apo(a) phenotypes between the controls, the APR patients with hypoalbuminaemia, and the APR patients with normoalbuminaemia (P = 0.183). In the APR patients, the serum concentrations of AAT and Hp were respectively 2.709 (0.822) g/L and 2.631 (1.340) g/L, whereas those of normal controls were respectively 1.422 (0.219) g/L (P < 0.001) and 0.956 (0.442) g/L (P < 0.001). In conclusion, the Lp(a) is one of the acute phase reactants whose synthesis concurrently increases with other APRs, especially those with a high sialic acid content. The increase of the serum Lp(a) concentrations in the APR patients is not related to serum albumin concentration.

Macular hole surgery in conjunction with endolaser photocoagulation

PURPOSE

To determine whether endolaser photocoagulation to the retinal pigment epithelium at the base of a macular hole increases the anatomic success rate of surgery.

METHODS

In a prospective consecutive clinical trial, eight eyes of seven patients with idiopathic macular hole underwent vitrectomy with posterior cortical vitreous removal and peeling of visible epiretinal membrane when present. A single shot of argon endolaser photocoagulation was applied to the retinal pigment epithelium at the center of the macular hole with a duration of 0.05 to 0.2 seconds and an intensity of 50 to 200 mW. After fluid-gas exchange was performed with 14% perfluoropropane gas, patients maintained face-down positioning for 2 weeks.

RESULTS

One eye with stage 2 macular hole, six eyes with stage 3 macular hole, and one eye with stage 4 macular hole were included. All eight eyes had a closed macular hole (100% anatomic success rate) at final examination 6 to 12 months after surgery. Best-corrected visual acuity improved 3 or more lines on the Early Treatment Diabetic Retinopathy Study visual acuity chart in all eyes. Four (50%) of the eight eyes had a final visual acuity of 20/40 or better.

CONCLUSIONS

Endolaser photocoagulation may be a useful adjunct to macular hole surgery but requires further investigation and long-term evaluation.

Fibrinogen gene polymorphism in a non-Caucasian population

OBJECTIVE

The purpose of this study was to investigate the two polymorphisms of fibrinogen gene (RsaI and MnlI RFLPs in the coding region of the fibrinogen gene) in Koreans, and their relation to plasma fibrinogen.

METHODS

Using PCR-amplified DNAs, RsaI and MnlI RFLPs were analyzed in 112 patients with coronary artery disease (CAD) and 137 healthy subjects. To compare the mean of plasma fibrinogen and lipid levels among different genotypes, one-way analysis of variance (ANOVA) test was performed.

RESULTS

Allele frequencies of fibrinogen gene polymorphism in Koreans were not significantly different between CAD and control groups; fibrinogen polymorphism in this population showed a lack of association with plasma fibrinogen levels, but significant association with BMI (p < 0.05).

CONCLUSION

This evidence suggests that in Korean populations, fibrinogen gene polymorphism is not a factor in the expression of atherosclerosis. There might, however, be an association between fibrinogen gene and obesity in such population.

The use of internal limiting membrane maculorrhexis in treatment of idiopathic macular holes

The purpose of this study was to assess surgical results of internal limiting membrane (ILM) maculorrhexis in macular hole surgery. This study is a part of continuing prospective clinical trial of our team of researchers. Thirteen eyes of 13 patients with idiopathic macular hole underwent vitrectomy with the removal of posterior cortical vitreous, peeling of the macular ILM, and intraocular gas tamponade, followed by postoperative face-down positioning. The excised specimens were evaluated with transmission electron microscopy. Complete closure of the hole was observed in all 13 eyes (100% anatomic success rate). Visual improvement of 2 or more lines on ETDRS visual acuity chart was achieved in 11 (85%) of the 13 eyes. Six (54.5%) eyes attained visual acuity of 20/50 or better. Electron microscopy showed ILM in the removed specimens. ILM maculorrhexis is a promising new surgical approach to close idiopathic macular holes but requires further investigation and long-term evaluation.

Association between apolipoprotein(a) polymorphism and Lp(a) levels in Koreans

In view of the clinical importance of lipoprotein(a) [(Lp(a)] in coronary artery disease (CAD), we investigated the apo(a) size polymorphism, sequence polymorphisms of five base repeats [(TTTTA)n] in the noncoding region, and of Met/Thr in the coding region of the apolipoprotein(a) [apo(a)] gene. The apo(a) polymorphisms were examined in 184 Korean patients with CAD and 121 healthy subjects. In size polymorphism, there was an inverse association between plasma Lp(a) levels and the apo(a) isoforms in the CAD group (p < 0.005). For (TTTTA)n sequence polymorphism, subjects with the 8/8 genotype were most frequently observed in the two groups. Plasma Lp(a) levels showed a significant difference between the 8/5 versus the 8/8 genotype in the CAD group. On the other hand, Lp(a) levels varied significantly among the genotypes of a Met/Thr polymorphism in normal controls (P < 0.01). The heterozygous genotype had an intermediate level of Lp(a) between the two homozygous genotypes, thereby showing gene dosage effect. Thus, it is possible that the apo(a) polymorphisms are responsible for variations in the Lp(a) levels.

Uptake of acetylated peptides from the small intestine in sheep and their nutritive value in rats

Acetylation is a potential method for protecting dietary peptides from degradation by rumen micro-organisms. As a first step in determining the nutritive value of acetylated peptides, their disappearance in the small intestine of sheep and their ability to support growth in a rat bioassay were measured. 15N-labelled peptides were prepared from lucerne which had been grown with 15N-labelled (NH4)2SO4 in the absence of Rhizobium. Peptides were prepared by enzymic hydrolysis of the extracted protein. Two peptide preparations were made using different proteinase mixtures. These mixtures contained peptides with an average molecular weight of 559 and 522 Da. They were treated with acetic anhydride, which resulted in 85 and 88% modification respectively, and their uptake from the small intestine was determined by injecting 1 g of untreated or acetylated peptides in a Cr-EDTA solution into the jejunum of two sheep fitted with jejunal catheters and ileal cannulas. Ileal digesta were collected and analysed for Cr and 15N. The uptake of dialanine (Ala2) and N-acetyl-Ala2 were compared in a similar way. The disappearance of 15N from lucerne peptides was high (88 and 93% respectively) and this was not affected significantly by acetylation (86 and 87%). Corresponding values for Ala2 and N-acetyl-Ala2 were both 96%, as measured by HPLC. It was therefore concluded that acetylation did not affect the uptake of peptides from the small intestine in sheep. Two feeding trials were carried out with rats. The first trial was carried out with a protein-free diet to which was added 10% lactalbumin or 5% lactalbumin and then a mixture of methionine-free amino acids, either alone or supplemented with Met, Gly-Met or acetylated Gly-Met. The rats grew equally well on all sources of Met, but failed to grow significantly on the mixture of Met-free amino acids. In the second trial the diet contained casein as 5.9% of the basal diet. Additional casein, pancreatic casein hydrolysate (peptides) and acetylated pancreatic casein hydrolysate (acetylated peptides) were compared as sources of amino acids, at inclusion rates of 100 g/kg final diet. Feed intake was similar with casein and peptides treatments, but was depressed by 23% with acetylated peptides. Live weight gain was 15 and 75% lower with the peptides and acetylated peptides diets respectively. Addition of lysine, arginine or histidine did not restore feed intake or weight gain of rats receiving acetylated peptides, but feed intake was restored immediately when peptides replaced acetylated peptides. When intake was restricted to 9 g/d and acetylated casein hydrolysate replaced half of the protein in the diet, rats gained weight less rapidly (1.44 v. 1.09 g/d) and retained less N, such that only 0.36 of the acetylated peptide-N was calculated to remain available to the animal. This N retention compared with 0.70 for unmodified casein. Thus, the rat bioassay indicated that certain specific peptides may well be of high nutritive value following acetylation, but that there may be problems of inappetance and inefficient utilization with acetylated peptide mixtures.

Migrating towards a client server architecture: a successful application in a 2,200-bed general hospital

Asan Medical Center (AMC) completed a major migration process of the hospital information system from a mainframe towards an open Unix client server architecture from August of 1993 to August of 1996. Along with the east wing extension of AMC, the number of inpatient beds is greatly increased from 1,000 to 2,200 and information transaction increased from 300,000 to 700,000. A gradual departmental migration strategy with local area network connection and data conversion between the two systems were applied. The successful migration process towards a client server architecture provided improved user interface, enhanced flexibility and productivity of the system, better integration with diverse medical devices and improved networking flexibility.