Search PubMed⌕ Search

Biomedical subjects

C Ahn

Publications and source records attributed to C Ahn.

At least 55 records · Page 3Linked to original sources
PubMed2001

Genetic heterogeneity in Korean families with autosomal-dominant polycystic kidney disease (ADPKD): the first Asian report.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary renal disease in adults, and the prevalence of this disease within the chronic haemodialysis patient population is known to be approximately 2% in Korea. So far, three genetic locus have been identified as being responsible for ADPKD, and approximately 85% of the cases in Western countries are related to the PKD1 gene. However, little information is available concerning the pattern of linkage analysis in Asian populations. METHODS: 48 families with hereditary renal cysts were recruited by consent and their molecular genetic characteristics were studied. Linkage analysis was done with microsatellite markers (PKD1: SM7, UT581, AC2.5, KG8, D16S418; PKD2: D4S423, D4S1534, D4S1542, D4S1544, D4S2460). Genomic DNA polymerase chain reaction (PCR) and polyacrylamide gel electrophoresis (PAGE) gel run were performed, and the resultant allele patterns were compared with sonographic findings. RESULTS: The results of this study showed that the ratio PKD1:PKD2 was 31:8, and that the PKD2 families exhibited a tendency toward a milder renal prognosis than the PKD1 families. CONCLUSION: We confirmed the applicability of linkage analysis for ADPKD in the Korean population, and our data confirmed a similar incidence of PKD1 (79%) and PKD2 (21%) in Korean patients as in the Western population.

Adolescent↗
PubMed2001

Glutathione S-transferase genotypes in systemic sclerosis and their association with clinical manifestations in early disease.

The glutathione S-transferases (GSTs) are a family of enzymes involved in limiting oxidative damage to tissues. Null alleles for one or more of the GST enzymes, especially GSTM1, reportedly occur more frequently in patients with Sjögren's syndrome and systemic lupus erythematosus who possess certain autoantibodies. Because systemic sclerosis (SSc) is a disease in which oxidative damage has been hypothesized to contribute both to immune dysfunction and tissue damage, we sought to determine if patients from a multi-ethnic cohort of SSc patients with early disease (< or =5 years) were more likely than ethnically-matched normal controls to have null alleles for GSTM1 (M1) and/or GSTT1 (T1), and if the null allele status correlated with any major disease features. The data show that while M1 and T1 null genotypes were not significantly increased in SSc compared to ethnically matched controls, their frequencies (especially T1 nulls) were significantly higher among SSc patients with hypertension and pulmonary involvement. This suggests that GST genotype may be a genetic factor that contributes to clinical disease expression in SSc.

Genotype↗
PubMed2001

Lack of association of a functionally relevant single nucleotide polymorphism of matrix metalloproteinase-1 promoter with systemic sclerosis (scleroderma).

Matrix metalloproteinase 1 (MMP-1) is necessary for degradation of interstitial collagen types I, II, and III, which are the major constituents of the extracellular matrix (ECM). Increased expression of MMP-1 has been correlated with invasiveness of certain malignancies and cartilage degradation in rheumatoid arthritis. Increased transcriptional activity of MMP-1 has been reported with a single nucleotide polymorphism (SNP) of the MMP-1 promoter. Systemic sclerosis (SSc) is characterized by increased accumulation and turnover of collagen and other components of ECM. Previous studies have reported increased expression of MMP-1 transcripts in SSc fibroblasts. Therefore, we sought to determine if SSc patients with early disease (< or =5 years) from a multi-ethnic cohort were more or less likely than ethnically-matched normal controls to have an increased frequency of the high promoter activity MMP-1 genotype and whether MMP-1 promoter genotypes correlated with any of the major clinical manifestations of SSc. The results show that the frequency of the high activity promoter genotype in either the heterozygous or homozygous state did not differ significantly between SSc patients and ethnically-matched controls, or between SSc patients with either diffuse or limited scleroderma. Furthermore, MMP-1 promoter genotypes did not significantly correlate with any of the major clinical manifestations of SSc.

Humans↗
PubMed2001

Systemic sclerosis in 3 US ethnic groups: a comparison of clinical, sociodemographic, serologic, and immunogenetic determinants.

OBJECTIVE: To determine whether ethnic factors influence the presentation, serologic expression and immunogenetics of systemic sclerosis (SSc), patients from 3 ethnic groups were compared for clinical features, SSc-associated autoantibodies, and human leukocyte antigen (HLA) class II alleles. METHODS: Fifty-four Hispanics, 28 African Americans, and 79 whites from Texas with recent-onset (less than 5 years) SSc enrolled in a prospective longitudinal study were assessed for sociodemographic, clinical, immunologic, immunogenetic, behavioral, and psychologic parameters using validated instruments and standard laboratory techniques. Serologic and immunogenetic characteristics from these patients and larger retrospective SSc cohorts of the same ethnic groups also were examined. RESULTS: Hispanics and African Americans in the prospective cohort were more likely to have diffuse skin involvement, skin pigmentary changes, digital ulcers, pulmonary hypertension (African Americans), and an overall lower sociodemographic status than whites, who had more facial telangiectasia and hypothyroidism. In the larger combined prospective and retrospective groups of SSc patients, whites were likely to have more anticentromere antibodies (ACA) and African Americans more anti-U1-ribonucleoprotein (RNP) and anti-U3-RNP (fibrillarin) autoantibodies. HLA-DQB1*0301 was significantly associated with SSc per se in all 3 ethnic groups; HLA-DRB1*11 correlated with the anti-topoisomerase I antibody response, and HLA-DRB1*01, DRB1*04, and DQB1*0501 with ACA. CONCLUSIONS: Important sociodemographic, clinical, and serologic differences exist between whites, African Americans, and Hispanics, despite shared genetic (HLA class II) predisposing factors. The impact of these differences on prognosis remain to be determined.

Adult↗
PubMed2001

Th1/Th2 predominance and proinflammatory cytokines determine the clinicopathological severity of IgA nephropathy.

BACKGROUND: IgA nephropathy is one of the most common forms of primary glomerulonephritis in adults. Its pathogenesis is complex. The nature of infiltrating and proliferating cells and of cellular mediators could contribute to the progression of IgA nephropathy towards end-stage renal failure. METHODS: To evaluate this hypothesis, we attempted to quantify the magnitude of intrarenal gene expression of various cytokines (IL-1 beta, TNF-alpha, IL-6, IL-15, IL-2, IFN-gamma, IL-10) and chemokines (IL-8, RANTES, MCP-1) in 48 renal core biopsy specimens, diagnosed as IgA nephropathy by immunofluorescence microscopy. Semi-quantitative reverse-transcriptase polymerase chain reaction using internal competitors was used for the quantification of gene transcripts. RESULTS: The expression of intrarenal gene transcripts of various cytokines and chemokines was closely interrelated, but not associated with the pathological grading system. The IFN-gamma/IL-10 ratio was higher in patients with renal dysfunction than in those with normal renal function (P=0.0483). Gene transcript levels of proinflammatory cytokines were related to the amount of proteinuria. In patients with severe glomerular sclerosis, the ratio of IFN-gamma/IL-10 gene transcripts was high (P=0.04). IL-10 gene transcript level was related to the severity of tubulointerstitial damage. The levels of gene expression of IL-10 (P=0.009), IFN-gamma (P=0.03), and TNF-alpha (P=0.005) were related to the degree of mesangial matrix expansion and the extent of intrarenal arteriolar changes correlated with the expression of the IL-8 gene transcript (r=0.43, P=0.004). CONCLUSIONS: We propose that Th1/Th2 predominance and the level of proinflammatory cytokines could determine the pathogenetic processes and the severity of the clinical manifestations of IgA nephropathy.

Adolescent↗
PubMed2001

The value of cystoscopy as an initial diagnostic modality for asymptomatic microscopic hematuria.

For the patients who visit outpatient clinics due to asymptomatic microscopic hematuria, cystoscopy has been looked upon as rather invasive compared to other diagnostic methods. We tried to elucidate the actual diagnostic value of cystoscopy in the initial evaluation of asymptomatic microscopic hematuria. We reviewed the results of cystoscopic examinations in 213 patients who visited our hospital due to asymptomatic microscopic hematuria. No definite lesion that could explain the microscopic hematuria was detected by means of IVP, urine cytology, and other nephrologic evaluations for all the patients. Among the abnormal cystoscopic findings in 55 patients, the lesions suspected to be directly related to microscopic hematuria were classified as 'significant lesions' (31 patients, 17.6%) which include entities such as bladder cancer (1.31%). 27 of 31 patients with significant lesions (85.2%) were over 50 yr old, and furthermore, 3 patients who were diagnosed as bladder tumor by cystoscopy were over 60 yr. Cystoscopy should be utilized as initial diagnostic modality in older patients with asymptomatic microscopic hematuria to rule out any possibility of bladder cancer occurrence. Further studies are needed to justify implementation of cystoscopy as an initial diagnostic modality in younger patients with asymptomatic microscopic hematuria.

Cystoscopy↗
PubMed2001

Does albumin preinfusion potentiate diuretic action of furosemide in patients with nephrotic syndrome?

The aim of this cross-over study was to investigate whether albumin infusion before furosemide administration could potentiate the diuretic action of furosemide. Seven patients with nephrotic syndrome were given the following infusions in random order on two separate days: 1) a sham solution followed by 160 mg of furosemide, 2) 100 ml of 20% human albumin followed by 160 mg of furosemide. Urine and serum furosemide concentrations were measured by high-performance liquid chromatography. The increment of urine volume was greater in albumin preinfusion than in furosemide alone. However, the increments of sodium and chloride excretions between furosemide alone and albumin preinfusion were not different. No significant differences in the pharmacokinetic parameters between the two treatments were observed: area under the concentration-time curve (AUC: 12.7+/-2.2 vs 15.1+/-4.4 g/ml hr), total plasma clearance (253+/-41 vs 256+/-54 ml/min), volume of distribution (341+/-34 vs 494+/-153 ml/kg), elimination half life (4.0+/-1.1 vs 4.6+/-0.8 hr), and urine furosemide excretion of the administered amount (16.5+/-7.3 vs 7.5+/-1.6%). In conclusion, these data show that albumin preinfusion potentiated diuresis, but not natriuresis, of furosemide without any change in the pharmacokinetics of the agent in patients with nephrotic syndrome.

Adolescent↗
PubMed2001

Differential effects of adenovirus-p16 on bladder cancer cell lines can be overcome by the addition of butyrate.

High frequency of p16 alteration and high local recurrence rate of bladder cancer make this cancer an ideal target for p16 gene therapy. However, a low transduction rate of p16 via adenoviral vector causes an inconsistent result. In this study, we have tested adenovirus-p16 in several bladder cancer cell lines and investigated a way of improving the low transduction rate. Adenovirus-p16 showed a strong antitumor effect on bladder cancer cell lines (253J and T24) with strong Coxackie-adenoviral receptor (CAR) expression but little antitumor effect on bladder cancer cell lines (J82 and HT1376) with little CAR expression. In this study, we suggest a simple way of overcoming the differential effects of the adenovirus. The addition of butyrate to media was found to increase the transduction rate of adenovirus remarkably and increase the antitumor effect of adenovirus-p16 in bladder cancer cell lines with little CAR expression. Butyrate effects were related with increased CAR expression on the cell surface as well as increased transgene expression from adenoviral vector. From these observations, application of adenovirus-p16 gene therapy with butyrate can overcome the obstacle of low gene transfer and enhance the antitumor effect of adenovirus-p16 in bladder cancer.

Adenoviridae↗
PubMed2001

Diffuse alveolar hemorrhage in lupus nephritis.

AIM: Diffuse alveolar hemorrhage (DAH) is a rare and catastrophic event in systemic lupus erythematosus (SLE) with a high mortality rate, and little information is available about the degree of renal involvement in this condition. PATIENTS AND METHODS: To evaluate the effects of renal impairment on the course of DAH, the hospital records of 7 patients (9 episodes) with DAH and SLE between 1988 and 1998 at Seoul National University Hospital were reviewed. A diagnosis of DAH was established when the patient had an acute pulmonary syndrome including either hemoptysis, new alveolar infiltrates on the chest radiograph, the presence of a falling hematocrit or hemorrhagic BAL. All patients were women and their median age was 26 years ranging between 23 and 39. All patients had concurrent lupus nephritis and 4 of them were classified as WHO class IV with renal pathology. RESULTS: Their median serum creatinine level at the time of DAH was 4.6 mg/dl (0.8 - 13.6), and the median daily proteinuria amount was 778 mg (436 - 6200). All of the patients received corticosteroid therapy, and intravenous cyclophosphamide was given to 3 cases. Hemodialysis was done in 3 cases, and 4 of the 7 patients died during an acute event. We reviewed five series about the clinical parameters, including the serum creatinine level, treatment and hospital outcome. From the results of the analysis, it was determined that concomitant infection (RR 4.2) and the use of mechanical ventilation (RR 6.1) were associated with the increased risk of mortality, but azotemia (sCr > 3.0 mg/dl) (RR 1.5) or hemodialysis therapy (RR 1.3) was not shown to have a significant association. CONCLUSION: It could be suggested that even though renal failure is combined with DAH in SLE patients, the same aggressive treatment results in a comparable outcome as patients with normal renal function.

Acute Disease↗
PubMed2001

Clinical significance of the fractional excretion of anions in metabolic acidosis.

The fractional excretion of anions has been proposed as a new index for the differential diagnosis of metabolic acidosis, identifying the properties of the conjugate base by examining the renal handling of the anion. Here, we investigated clinical significance of the fractional excretion of anions in pathophysiologic diagnosis of metabolic acidosis by measuring urine ammonium (NH4+) excretion, the ratio of A plasma anion gap/delta plasma HCO3- concentration (deltaAG/deltaHCO3-), and fractional excretion of anions in three different groups of metabolic acidosis: acid overproduction (8 patients with lactic acidosis, 8 with diabetic ketoacidosis, 3 with hippuric acidosis following glue sniffing), acid underexcretion (10 patients with chronic renal failure) and normal controls (10 normal volunteers who underwent 3-day NH4Cl loading). As expected, urine NH4+ excretion was higher in overproduction acidosis than in acid-loaded normal controls (88.1 +/- 12.3 vs. 54.0 +/- 3.7 mmol/day, p < 0.05), and it was lower in chronic renal failure than in acid-loaded normal controls (12.8 +/- 1.7 vs. 54.0 +/- 3.7 mmol/day, p < 0.05). The fractional excretion of anions had no difference between overproduction acidosis and chronic renal failure (41.2 +/- 42.8% vs. 41.0 +/- 8.1%). However, the fractional excretion of anions showed significant differences between the subgroups in acid overproduction (lactic acidosis, 4.7 +/- 0.3%; diabetic ketoacidosis, 45.8 +/- 3.1%; hippuric acidosis, 126.0 +/- 14.4%; p < 0.05). The ratio of plasma deltaAG/deltaHCO3- also exhibited significant differences between the subgroups in acid overproduction (lactic acidosis, 1.5 +/- 0.1; diabetic ketoacidosis, 1.0 +/- 0.1; hippuric acidosis, 0.3 +/- 0.1; p < 0.05). There was an inverse linear correlation between the fractional excretion of anions and the ratio of plasma deltaAG/deltaHCO3- (r2 =-0.89, p < 0.05). In conclusion, determination of the fractional excretion of anions may provide a useful clue to the differential diagnosis of metabolic acidosis caused by acid overproduction.

Acidosis↗
PubMed2001

Renal biopsy in elderly patients: clinicopathological correlation in 117 Korean patients.

AIM: In the elderly with renal disease, the clinical presentations are frequently inconsistent with the pathologic findings. We tried to clarify the differences in pathological findings between the young and the elderly, in Korea and in Western countries, and the usefulness of a percutaneous renal biopsy in the elderly with renal disease. PATIENTS AND METHODS: We analyzed the clinical presentations and spectrums of renal histopathology by reviewing medical records and renal biopsy reports retrospectively in 117 Korean patients aged 60 years or more with renal disease. RESULTS: 85 patients had primary renal disease. The remaining 32 patients had renal diseases associated with systemic conditions. Out of the 85 patients with primary renal disease, 61 cases presented as idiopathic nephrotic syndrome. Compared with renal biopsy results of younger adult patients (age 15-59, n = 1,908), membranous nephropathy, crescentic glomerulonephritis, membranoproliferative glomerulonephritis, amyloidosis, light chain disease, and thrombotic thrombocytopenic purpura were more prevalent, but IgA nephropathy and lupus nephritis were less common in the elderly patients. In clinical presentation, nephrotic syndrome and rapidly progressive renal failure were more prevalent, but asymptomatic urinary abnormality was less common in elderly patients. The responsiveness to treatment was good in elderly patients with minimal-change lesion (complete remission in all patients) but poor in crescentic glomerulonephritis, IgA nephropathy, and membranoproliferative glomerulonephritis. From the above findings, the clinical presentation, patterns of histopathology and responsiveness to treatment of elderly Korean patients were similar to those of the younger Korean control group and the Western elderly group. CONCLUSION: Percutaneous renal biopsy is a useful diagnostic aid and can be used as a therapeutic guideline even in elderly patients with renal disease.

Aged↗
PubMed2000

Nudf, a fungal homolog of the human LIS1 protein, functions as a dimer in vivo.

The NUDF protein is required for nuclear migration through the mycelium of the filamentous fungus Aspergillus nidulans. It is of particular interest, because it closely resembles a human protein, LIS1, that is required for development of the cerebral cortex. Both are approximately 50-kDa proteins with a short N-terminal predicted coiled coil and seven WD-40 domains in the C-terminal half of the molecule. They also interact with homologous proteins, suggesting that they may have similar biochemical functions. Here we describe the purification to homogeneity of NUDF protein in a single step from a cell-free extract of A. nidulans. We demonstrate that NUDF is a homodimer, that its dimerization occurs via the N-terminal coiled coil region of the molecule, and that it must be a dimer to support the growth of A. nidulans.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed2000

Three-port microlaparoscopic cholecystectomy in 159 patients.

BACKGROUND: Laparoscopic cholecystectomy has undergone many refinements including reductions in port size and number. This study attempts to determine whether further reduction in port size from that previously reported by us can reduce postoperative pain without compromising the efficacy of the surgery. METHODS: In this study, 159 patients underwent laparoscopic cholecystectomy with three ports: one 5-mm umbilical port, one 3-mm subxiphoid port, and one 3-mm port in the right subcostal position. Data were collected prospectively for each patient on the duration of analgesic use, quantity of analgesic tablets consumed, postoperative pain, most painful incision, and days of recovery required before return to activity and work. These measures were compared with those collected from a group of 100 patients who had undergone laparoscopic cholecystectomy with three 5-mm ports in a previous study. RESULTS: Patients in the current study group required analgesics for a longer duration (4 vs 2.9 days; p = 0.001), used more analgesic tablets (10.7 vs 8.1; p = 0.007), and reported greater postoperative discomfort (5 vs 4.1; p = 0.016) as compared with all in the 5-mm port group. The 3-mm port group needed more days for recovery before leaving the house (2.9 vs 2.7; p = 0.504), but they returned to work earlier (5.1 vs 5.9; p = 0.065) than the group that had undergone cholecystectomy with three 5-mm ports, although there was not a significant difference between the groups. Operative time increased from 18.5 to 20.9 min (p = 0.054) in the group with two 3-mm ports. Five patients (3.1%) in the current group required enlargement of a port to complete the procedure, as compared with none in the comparison group. There was one complication (0.6%), as compared with two complications (2.0%) in the previous group. CONCLUSIONS: This study did not demonstrate a reduction in postoperative pain or a consistent improvement in recovery when the port size was reduced at the subcostal and subxiphoid positions. It did, however, show that ports could safely be reduced in size without a negative impact on the surgeon's ability to perform a cholecystectomy. Reducing port size can be a tool in the surgeon's armamentarium for use in the attempt to optimize cosmetic results.

Abdominal Muscles↗
PubMed2000

Prevalence of coronary artery disease, complex ventricular arrhythmias, and silent myocardial ischemia and incidence of new coronary events in older persons with chronic renal insufficiency and with normal renal function.

In a prospective study of 98 persons > or = 65 years of age with chronic renal insufficiency (serum creatinine > 3.0 mg/dl) for > 1 year and 98 age- and sex-matched persons with normal renal function (serum creatinine < or = 1.2 mg/dl), new coronary events developed at 23-month follow-up in 69 persons (70%) with chronic renal insufficiency and at 48-month follow-up in 24 persons (24%) with normal renal function (p < 0.0001). Significant independent risk factors for new coronary events were age (risk ratio 1.1), prior coronary artery disease (risk ratio 3.5), complex ventricular arrhythmias diagnosed by 24-hour ambulatory electrocardiography (risk ratio 2.5), silent myocardial ischemia diagnosed by 24-hour ambulatory electrocardiography (risk ratio 1.9), and chronic renal insufficiency (risk ratio 3.4).

Aged↗
PubMed2000

Comprehensive follow-up care and life-threatening illnesses among high-risk infants: A randomized controlled trial.

CONTEXT: Inner-city high-risk infants often receive limited and fragmented care, a problem that may increase serious illness. OBJECTIVE: To assess whether access to comprehensive care in a follow-up clinic is cost-effective in reducing life-threatening illnesses among high-risk, inner-city infants. DESIGN: Randomized controlled trial. SETTING AND PARTICIPANTS: A total of 887 very-low-birth-weight infants born in a Texas county hospital between January 1988 and March 1996 and followed up in a children's hospital clinic. One hundred four infants who became ineligible or died after randomization but before nursery discharge were excluded from the analysis. INTERVENTIONS: Infants were randomly assigned to receive routine follow-up care (well-baby care and care for chronic illnesses; n = 441) or comprehensive care (which included the components of routine care plus care for acute illnesses, with 24-hour access to a primary caregiver; n = 446). MAIN OUTCOME MEASURES: Life-threatening illnesses (ie, causing death or hospital admission for pediatric intensive care) occurring between nursery discharge and age 1 year, assessed by blinded evaluators from inpatient charts and state Medicaid and vital statistics records; and hospital costs (estimated from department-specific cost-to-charge ratios). RESULTS: Comprehensive care resulted in a mean of 3.1 more clinic visits and 6.7 more telephone conversations with clinic staff (P<.001 for both). One-year outcomes were unknown for fewer comprehensive-care infants than routine-care infants (9 vs 28; P =.001). Identified deaths were similar (11 in comprehensive care vs 13 in routine care; P =.68). The comprehensive-care group had 48% fewer life-threatening illnesses (33 vs 63; P<.001), 57% fewer intensive care admissions (23 vs 53; P =.003), and 42% fewer intensive care days (254 vs 440; P =.003). Comprehensive care did not increase the mean estimated cost per infant for all care ($6265 with comprehensive care and $9913 with routine care). CONCLUSION: Comprehensive follow-up care by experienced caregivers can be highly effective in reducing life-threatening illness without increasing costs among high-risk inner-city infants. JAMA. 2000;284:2070-2076.

Acute Disease↗
PubMed2000

Platelet Pl(A2) allele and incidence of coronary heart disease: results from the Atherosclerosis Risk In Communities (ARIC) Study.

BACKGROUND: The major platelet integrin glycoprotein IIb-IIIa plays a primary role in platelet aggregation and acute thrombus formation at the site of vascular injury. A genetic polymorphism of glycoprotein IIb-IIIa (Pl(A)) has recently been proposed as a potential genetic factor linking to platelet hyperaggregability and increased risk of myocardial infarction. Despite numerous, mostly nonprospective studies, the role of this polymorphism as a clinically relevant, inherited risk factor for coronary heart disease (CHD) is still controversial. The purpose of this study was to determine whether Pl(A2) is a risk factor for incident CHD and whether it is correlated with increased platelet activation in a case-cohort study nested within a prospective epidemiologic investigation. METHODS AND RESULTS: Blood samples were collected and processed from the Atherosclerosis Risk in Communities Study cohort at the baseline examination (1987 to 1989). They were stored at -80 degrees C. Pl(A1/A2) genotype and plasma beta-thromboglobulin levels were determined in 439 incident CHD cases and a reference cohort sample of 544 (of whom 18 were also CHD cases). The prevalence of the Pl(A2) allele was not different in cases versus noncases. No significant correlation between CHD risk factors and the Pl(A2) allele was noted either. Platelet activation, as measured by plasma beta-thromboglobulin levels, was not enhanced in individuals with the Pl(A2) allele. CONCLUSIONS: This prospective study indicates that healthy individuals carrying the Pl(A2) allele do not have an increased risk of CHD.

Alleles↗