OBJECTIVES: Breast cancer is the second most common cancer among Korean women. Because breast cancer is strongly associated with negative emotional and physical changes, early detection and treatment of breast cancer are very important. As a supporting tool for classifying breast cancer, we tried to identify the best meta-learner model in a stacking ensemble when the same machine learning models for the base learner and meta-learner are used. METHODS: We used machine learning models, such as the gradient boosted model, distributed random forest, generalized linear model, and deep neural network in a stacking ensemble. These models were used to construct a base learner, and each of them was used as a meta-learner again. Then, we compared the performance of machine learning models in the meta-learner to determine the best meta-learner model in the stacking ensemble. RESULTS: Experimental results showed that using the GBM as a meta-learner led to higher accuracy than that achieved with any other model for breast cancer data and using the GLM as a meta learner led to low root-mean-squared error for both sets of breast cancer data. CONCLUSIONS: We compared the performance of every meta-learner model in a stacking ensemble as a supporting tool for classifying breast cancer. The study showed that using specific models as a metalearner resulted in better performance than single classifiers, and using GBM and GLM as a meta-learner is appropriate as a supporting tool for classifying breast cancer data.
Breast Neoplasms ; Breast ; Classification ; Female ; Forests ; Humans ; Linear Models ; Machine Learning ; Medical Informatics ; Statistics as Topic

PURPOSE: The aim of the study is to evaluate the health-related quality of life, psychological symptoms, distress, and sense of coherence in adult haematopoietic stem cell transplantation survivors. METHODS: Fifty two survivors completed four questionnaires after the transplantation. The questionnaires were the Functional Assessment of Cancer Therapy-BMT Scale, the National Cancer Center Psychological Symptom Inventory, the Distress Thermometer, and the Sense of Coherence scale. RESULTS: Quality of life was positively correlated with sense of coherence, whereas sense of coherence was negatively correlated with all psychological symptoms and distress. Hierarchical regression analyses revealed that sense of coherence was the only significant predictor of quality of life after controlling for sex and age at transplantation. Model 2 explained 33.2% of the total variance of quality of life. CONCLUSION: Supporting patients towards improving comprehensibility, manageability and meaningfulness, the three components of sense of coherence, may be beneficial and improve outcomes. Individually pre-transplant and post-transplant assessments of sense of coherence may be of clinical importance, in order to identify patients with unmet needs and to provide rolonged support.
Adult* ; Hematopoietic Stem Cell Transplantation ; Humans ; Quality of Life* ; Sense of Coherence ; Stem Cell Transplantation* ; Stem Cells* ; Survivors* ; Symptom Assessment ; Thermometers

Thrombotic microangiopathy (TMA) is a rare complication of gemcitabine treatment. A 55-year-old man with a history of urothelial cancer underwent right ureteronephrectomy and palliative chemotherapy. The patient presented with dyspnea, generalized edema with foamy urine, and new-onset hypertension with acute kidney injury (AKI). Although AKI with oliguria was evident, thrombocytopenia and hemolytic anemia were not overt. To determine the cause of rapidly progressive azotemia, kidney biopsy was performed despite a single kidney and revealed chronic TMA. Microangiopathic hemolytic anemia and thrombocytopenia developed after renal biopsy. Diagnosed as gemcitabine-induced TMA, gemcitabine cessation and active treatment including steroids, plasmapheresis, and rituximab were carried out, but the patients condition progressed to a dialysis-dependent state. Gemcitabine-induced TMA is often difficult to diagnose because of its variable clinical course. Therefore, heightened awareness of this potentially lethal complication of gemcitabine is essential; renal biopsy may be helpful.
Acute Kidney Injury ; Anemia, Hemolytic ; Azotemia ; Biopsy ; Drug Therapy ; Dyspnea ; Edema ; Humans ; Hypertension ; Kidney* ; Middle Aged ; Oliguria ; Plasmapheresis ; Steroids ; Thrombocytopenia ; Thrombotic Microangiopathies* ; Rituximab

BACKGROUND/AIMS: New definitions of acute kidney injury (AKI) have recently emerged. Some studies have suggested that duration of AKI is an additional predictive parameter for mortality. Here, we evaluated whether AKI duration was predictive of long-term mortality in patients with hospital-acquired acute kidney injury (HAAKI). METHODS: We prospectively enrolled patients who developed HAAKI at an urban university hospital, from September 2007 to August 2008 and followed them until December 2011. Patients were divided into two groups by duration of the AKI (1 to 5 days vs. > or = 6 days), and long-term mortality was compared. RESULTS: HAAKI developed in 1.2% of patients during the enrollment period. The median follow-up period was 240 days (interquartile range, 53 to 1,428). In 42.3% of patients (n = 52), the AKI lasted 1 to 5 days, while it lasted > or = 6 days in 57.7% (n = 71). Survival analysis showed that a longer duration of AKI increased the risk of death. Long-term survival was significantly different in the two groups. CONCLUSIONS: The duration of AKI influenced mortality rates in hospitalized patients. Thus, AKI duration is a parameter affecting mortality in HAAKI.
Acute Kidney Injury/diagnosis/etiology/*mortality/therapy ; Aged ; Female ; *Hospitalization ; Hospitals, University ; Humans ; Kaplan-Meier Estimate ; Male ; Middle Aged ; Prognosis ; Proportional Hazards Models ; Prospective Studies ; Republic of Korea ; Risk Factors ; Time Factors

A 34-yr-old female was diagnosed as being brain dead. Preoperative ultrasound revealed no abnormal focal lesions. However, the horseshoe kidney was identified during organ harvest. En bloc nephrectomy was performed. The kidney was divided at the midline of isthmus. The divided right kidney was discarded due to numerous arteries and veins. The divided left kidney was transplanted. After declamping, the kidney was well perfused and started clearing. Resistive index was 0.72. Glomerular filtration ratio was 84.69 mL/min on postoperative day 14. The horseshoe kidney can be successfully transplanted and could be a good solution for the shortage of organ donors.
Adult ; Cadaver ; Female ; Humans ; Kidney/*abnormalities/ultrasonography ; Kidney Failure, Chronic/diagnosis/*therapy ; Kidney Transplantation/*methods ; *Tissue Donors ; Tissue and Organ Harvesting/*methods ; Treatment Outcome

A 34-yr-old female was diagnosed as being brain dead. Preoperative ultrasound revealed no abnormal focal lesions. However, the horseshoe kidney was identified during organ harvest. En bloc nephrectomy was performed. The kidney was divided at the midline of isthmus. The divided right kidney was discarded due to numerous arteries and veins. The divided left kidney was transplanted. After declamping, the kidney was well perfused and started clearing. Resistive index was 0.72. Glomerular filtration ratio was 84.69 mL/min on postoperative day 14. The horseshoe kidney can be successfully transplanted and could be a good solution for the shortage of organ donors.
Adult ; Cadaver ; Female ; Humans ; Kidney/*abnormalities/ultrasonography ; Kidney Failure, Chronic/diagnosis/*therapy ; Kidney Transplantation/*methods ; *Tissue Donors ; Tissue and Organ Harvesting/*methods ; Treatment Outcome

BACKGROUND: In vitro detection of the allergen-specific IgE antibody (sIgE) is a useful tool for the diagnosis and treatment of allergies. Although multiple simultaneous allergen tests offer simple and low-cost screening methods, these platforms also have limitations with respect to multiplexibility and analytical performance. As an alternative assay platform, we developed and validated a microarray using allergen extracts that we termed “GOLD” chip. METHODS: Serum samples of 150 allergic rhinitis patients were used in the study, and the diagnostic performance of the microarray was compared with that of AdvanSure (LG Life Sciences, Daejun, Korea) and ImmunoCAP (Phadia, Uppsala, Sweden). Standard IgE samples were used for the quantitative measurement of sIgEs. RESULTS: The microarray-based assay showed excellent performance in the quantitative measurement of sIgEs, demonstrating a linear correlation within the range of sIgE concentrations tested. The limit of detection (LOD) was lower than 0.35 IU/mL, which is the current standard for the LOD cut-off. The assay also provided highly reproducible sets of data. The total agreement percentage of positive and negative calls was 92.2% compared with ImmunoCAP. Moreover, an outstanding correlation was observed between the microarray and the ImmunoCAP results, with Cohen's kappa and Pearson correlation coefficient values of 0.80 and 0.79, respectively. CONCLUSIONS: The microarray-based in vitro diagnostic platform offers a sensitive, reproducible, and highly quantitative method to detect sIgEs. The results showed strong correlations with that of ImmunoCAP. These results suggest that the new allergen microarray can serve as a useful alternative to current screening platforms, ultimately becoming a first-line screening method.
Biological Science Disciplines ; Diagnosis ; Humans ; Hypersensitivity* ; Immunoglobulin E ; In Vitro Techniques* ; Limit of Detection ; Mass Screening ; Methods ; Rhinitis, Allergic

BACKGROUND: For creatinine measurement, the enzymatic method is known to be more accurate than the Jaffe method; however, the latter is still widely used. We evaluated the performance of the CRE2 reagent (Siemens Healthcare Diagnostics Inc., USA), which uses a modified Jaffe method. METHODS: Three quality control standards were used for precision evaluations of CRE2 on Dimension VISTA 500 instrument (Siemens). Moreover, the linearity and carryover characteristics were assessed. Sixty-eight creatinine results obtained using the CRE2 and ECREA (enzymatic) reagents (Siemens) were compared with those obtained using the L-CRE (enzymatic) reagent (Shinyang Diagnostics, Korea). The accuracy of CRE2, ECREA, and L-CRE was evaluated using a standard reference material. RESULTS: The CV of within-run (0.7–2.4%), between-run (0.4–1.7%), between-day precision (0.7–0.9%) for three standards, and total CV for medium (1.6%) and high levels (1.3%) satisfied the analytical goal. The linearity for CRE2 was excellent (R2=0.999). Comparisons of CRE2 and ECREA to L-CRE were well correlated (r=0.996 and 0.997, respectively). In comparison with L-CRE, 5 CRE2 results and 15 ECREA results exceeded minimum bias goal (5.1%) in samples with creatinine levels of >1 mg/dL. The carryover rate was −0.04%. In terms of accuracy, the percent bias values of CRE2, ECREA, and L-CRE were 7.4, −6.4, and −3.4, respectively, for low level; and 3.9, −1.5, and 0.7, respectively, for high level. CONCLUSIONS: For creatinine measurements, the CRE2 reagent showed good performance. It can be used in the diagnosis, treatment monitoring, and risk assessment of kidney diseases.
Bias (Epidemiology) ; Creatinine* ; Delivery of Health Care ; Diagnosis ; Indicators and Reagents ; Kidney Diseases ; Methods ; Quality Control ; Risk Assessment

OBJECTIVES: In July 2019, there were multiple reports on patients with hepatitis A among the visitors of a restaurant in Busan. The current study presents the results of an epidemiological investigation and outlines the supplementary measures that would help with hepatitis A control. METHODS: A cohort study was conducted for all 2,865 customers who visited restaurant A from June to July. Using a standardized questionnaire, participants reported the presence of hepatitis A symptoms and whether they had consumed any of 19 food items. As for participants who had visited public health centers, their specimens were collected. RESULTS: From the study cohort, 155 participants (5.4%) had confirmed hepatitis A. The epidemic curve was unimodal, and the median number of days from the restaurant visit to symptom onset was 31 days. A genotype analysis indicated that 89 of 90 tested patients had hepatitis A virus (HAV) genotype 1A. The results of a multivariate logistic regression analysis indicated that the ingestion of salted clams increased the risk of hepatitis A by 68.12 times (95% confidence interval [CI], 9.22 to 510.87). In an unopened package of salted clams found and secured through traceback investigation, HAV genotype 1A was detected. CONCLUSIONS To prevent people from ingesting uncooked clams, there needs to be more efforts to publicize the dangers of uncooked clams; the food sampling test standards for salted clams should also be expanded. Furthermore, a laboratory surveillance system based on molecular genetics should be established to detect outbreaks earlier.