Extrahepatic Malignancies Are the Leading Cause of Death in Patients with Chronic Hepatitis B without Cirrhosis: A Large Population-Based Cohort Study

(1) Background: Accurate statistics on the causes of death in patients with chronic hepatitis B (CHB) are lacking. We investigated mortality rates and causes of death over time. (2) Methods: Data on patients newly diagnosed with CHB from 2007 to 2010 (cohort 1, n = 223,424) and 2012 to 2015 (cohort 2, n = 177,966) were retrieved from the Korean National Health Insurance Service. Mortality data were obtained from Statistics Korea. The causes of death were classified as liver-related (hepatic decompensation or hepatocellular carcinoma [HCC]) or extrahepatic (cardiovascular-related, cerebrovascular-related, or extrahepatic malignancy-related). (3) Results: Over a 10-year follow-up period of 223,424 patients (cohort 1) with CHB, the overall mortality was 1.54 per 100 person-years. The mortality associated with HCC was the highest (0.65 per 100 person-years), followed by mortality related to extrahepatic malignancies (0.26 per 100 person-years), and cardio/cerebrovascular diseases (0.18 per 100 person-years). In the non-cirrhotic CHB (87.4%), 70% (11,198/15,996) of patients died due to non-liver-related causes over ten years. The 10-year overall mortality was 0.86 per 100 person-years. Among these, mortality due to extrahepatic malignancies had the highest rate (0.23 per 100 person-years), followed by mortality related to HCC (0.20 per 100 person-years), and cardio/cerebrovascular diseases (0.16 per 100 person-years). The 5-year mortality associated with extrahepatic malignancies increased from 0.36 per 100 person-years (cohort 1) to 0.40 per 100 person-years (cohort 2). (4) Conclusions: Mortality related to HCC decreased, whereas mortality related to extrahepatic malignancies increased in the antiviral era. Extrahepatic malignancies were the leading cause of death among patients with CHB without cirrhosis.

Feasibility of Applying the OMOP Common Data Model to Traditional Eastern Asian Medicine Dataset

To evaluate the feasibility of applying the Observational Medical Outcome Partnership (OMOP) Common Data Model (CDM) to databases of traditional East Asian medicine (TEAM), we composed a TEAM dataset and transformed it to the OMOP CDM. We found that some important TEAM information entities could not be transformed to the OMOP CDM (version 6.0) data fields. We suggest to develop data fields and guideline for transforming TEAM data to the OMOP CDM.

Smoking Increases the Risk of Hepatocellular Carcinoma and Cardiovascular Disease in Patients with Metabolic-Associated Fatty Liver Disease

The association of smoking with hepatocellular carcinoma (HCC) or cardiovascular disease (CVD) has been reported, but the study of its relationship with metabolic-associated fatty liver disease (MAFLD) is limited. We aimed to investigate the effect of smoking on the incidence of HCC or CVD in MAFLD patients. Using the Korean nationwide health screening database, we analyzed subjects between 2001 and 2015. A total of 283,088 subjects including 110,863 MAFLD patients and 172,225 controls were analyzed. Smoking status was divided by non-smoker, ex-smoker, or current smoker. In the follow-up period, a total of 2903 (1.0%) subjects developed HCC, and the MAFLD group (1723, 1.6%) had a significantly higher incidence than the control group (1180, 0.7%). In the MAFLD group, current smokers showed significantly higher risk of HCC compared to non-smokers (adjusted HR 1.24, 95% CI 1.08-1.41), whereas the control group did not (adjusted HR 1.07, 95% CI 0.89-1.30). A total of 18,984 (6.7%) patients developed CVD, and the incidence was significantly higher in the MAFLD group (8688, 7.8%) than in the control group (10,296, 6.0%), similar to HCC. The risk of CVD in current smokers increased by 22% compared to non-smokers in the MAFLD group (adjusted HR 1.22, 95% CI 1.15-1.30) and by 21% (adjusted HR 1.21, 95% CI 1.13-1.29) in the control group. Based on sex stratification, men showed increased incidence of both HCC and CVD by smoking, whereas women had only increased risk of CVD. Smoking significantly increases the incidence of HCC and CVD in MAFLD patients; thus, it is highly recommended to quit smoking completely in the population with MAFLD.

Residual risks of comorbidities after parathyroidectomy in a nationwide cohort of patients with primary hyperparathyroidism

PURPOSE

Primary hyperparathyroidism (PHPT) is a common endocrine disorder with increasing incidence, while epidemiologic data in Asian population has been lacking. Therefore, we aimed to identify the incidence, prognosis, and prognostic factors of PHPT patients who underwent parathyroidectomy in Korea.

METHODS

In this retrospective nationwide cohort, patients with PHPT were defined as those with diagnostic codes of PHPT and procedural codes for parathyroidectomy, excluding chronic renal failure or secondary hyperparathyroidism based on National Health Insurance Services database in Korea in 2002-2018. Main primary outcomes were all-cause mortality, cardiovascular, and cerebrovascular events.

RESULTS

A total of 5561 patients were diagnosed with PHPT and had parathyroidectomy. The mean age was 54.5 years, and 71.8% were women. The age-standardized incidence was 10.1/100,000 person-year in 2018, rising from 1.7/100,000 person-year in 2002. During a mean of 5.9 years, history of cardiovascular disease, mood disorder, and genitourinary stone had increased risks of mortality with hazard ratios (HRs) of 1.59 (95% confidence interval [CI] 1.10-2.29), 1.43 (CI 1.14-1.80), and 1.40 (CI 1.09-1.80), respectively. History of hypertension, cerebrovascular disease, diabetes mellitus, and mood disorder were risk factors for cardiovascular events with HRs of 1.42 (CI 1.22-1.66), 1.29 (CI 1.05-1.58), 1.22 (CI 1.07-1.40), and 1.14 (CI 1.00-1.29), respectively. Mood disorder was a significant risk factor for cerebrovascular events (HR 1.30, CI 1.11-1.52).

CONCLUSION

The incidence of PHPT patients who underwent parathyroidectomy has been rising in Korea as reported in other countries. Patients with complications, especially mood disorder, had increased cardiovascular and cerebrovascular events and mortality risks.

Herbal medicine for the treatment of chronic rhinosinusitis: A systematic review and meta-analysis

Objectives: Chronic rhinosinusitis (CRS) is a disease with a high prevalence and a high socioeconomic burden. This study aimed to conduct a comprehensive systematic review to update the evidence on the use of herbal medicine (HM) for CRS treatment.

Methods: A total of 14 electronic databases for randomized controlled trials (RCTs) evaluating the effects of HM on the treatment of CRS were searched for articles published before July 2021. The primary outcome was CRS severity post-treatment, measured with the Visual Analogue Scale (VAS) and Total Effective Rate (TER). The risk of bias of the included studies and the quality of evidence of the main findings were assessed using the Cochrane Collaboration’s risk of bias tool and the Grading of Recommendations, Assessment, Development, and Evaluations tool.

Results: A total of 80 RCTs were included. Compared to placebo, HM significantly improved CRS severity as measured by TER and VAS. When HM was compared with conventional treatment (CT) as monotherapy or adjuvant therapy, CRS severity measured by TER and VAS, quality of life, Lund-Kennedy endoscopy score, Lund-Mackay computed tomography score, and nasal mucociliary function were significantly improved in the HM group. No serious adverse events associated with HM were reported. The risk of bias was generally unclear, and the quality of evidence ranged from moderate to low.

Conclusion: This review found some limited clinical evidence that HM or HM combined with CT may be more effective and safer than CT alone in treating CRS. However, the methodological quality of the included studies was generally low, and the quality of the evidence needs to be improved.

Antifungal activity of streptavidin C1 and C2 against pathogens causing Fusarium wilt

Fusarium wilt is caused by the soil-inhabiting fungus Fusarium oxysporum ff. spp. and is one of the most devastating plant diseases, resulting in losses and decreasing the quality and safety of agricultural crops. We recently reported the structures and biochemical properties of two biotin-binding proteins, streptavidin C1 and C2 (isolated from Streptomyces cinnamonensis strain KPP02129). In the present study, the potential of the biotin-binding proteins as antifungal agent for Fusarium wilt pathogens was investigated using recombinant streptavidin C1 and C2. The minimum inhibitory concentration of streptavidin C2 was found to be 16 µg ml^-1 for inhibiting the mycelial growth of F. oxysporum f.sp. cucumerinum and F. oxysporum f.sp. lycopersici, while that of streptavidin C1 was found to be 64 µg ml^-1 . Compared with the nontreated control soil, the population density of F. oxysporum f.sp. lycopersici in the soil was reduced to 49·5% and 39·6% on treatment with streptavidin C1 (500 µg ml^-1 ) and C2 (500 µg ml^-1 ), respectively. A greenhouse experiment revealed that Fusarium wilt of tomato plants was completely inhibited on soil drenching using a 50-ml culture filtrate of the streptavidin-producing strain KPP02129.

Epidemiology and Comorbidity of Adrenal Cushing Syndrome: A Nationwide Cohort Study

CONTEXT

Adrenal Cushing syndrome (CS) is a major subtype of CS and has a high surgical cure rate. However, only a few studies have investigated the epidemiology and long-term outcomes of adrenal CS.

OBJECTIVE

We aimed to investigate the nationwide epidemiology, long-term prognosis, and postoperative glucocorticoid replacement therapies of adrenal CS in Korea.

DESIGN

Retrospective cohort study.

SETTING

A nationwide claim database.

PATIENTS

Adrenal CS patients who were defined as having undergone adrenalectomy, a diagnosis code of CS, and not having pituitary gland surgery.

MAIN OUTCOME MEASURES

Crude incidence and age-standardized incidence rates, long-term mortality, comorbidities diagnosed preoperatively or developed postoperatively, and the pattern of postoperative glucocorticoid replacement therapy.

RESULTS

From 2002 to 2017, there were a total of 1199 new adrenal CS patients, including 72 patients with adrenocortical carcinoma (malignant adrenal CS), in Korea. The crude and age-standardized incidence rates were 1.51 and 1.27 per million person-years, respectively. The overall standardized mortality ratio was 3.0 (95% confidence interval [CI], 2.4-3.7) for benign adrenal CS and 13.1 (95% CI, 7.6-18.6) for malignant adrenal CS. Adrenal CS patients had a high risk of having coronary artery disease, stroke, metabolic diseases, and depression. A similar proportion of patients were diagnosed with these comorbidities both preoperatively and postoperatively, suggesting a significant residual risk even after adrenalectomy. The median time of postoperative glucocorticoid replacement therapy was 10.1 months, and the major types of glucocorticoids used were prednisolone (66.6%) and hydrocortisone (22.4%).

CONCLUSIONS

Adrenal CS is associated with multiple comorbidities even after treatment, which necessitates meticulous postoperative care.

Liquid crystal filter based tunable transmitter for 25Gps wavelength division multiplexing-passive optical network fronthaul

A novel tunable transmitter structure based on liquid crystal filter, to the best of our knowledge, is presented. The structure is designed for application to 5G fronthaul and supports 25 Gbps dense wavelength division multiplexing (WDM) transmission and tunable range of 35 nm. The design takes into account easy change of operation band over coarse WDM grid. Prototype samples are developed to test feasibility of the design.

Association between use of benzodiazepines and occurrence of acute angle-closure glaucoma in the elderly: A population-based study

OBJECTIVE

Because benzodiazepines (BZDs) can affect pupillae muscles, their use could be a risk factor for acute angle-closure glaucoma (AACG), which is an ophthalmic emergency. However, there is no research evidence for the association between BZDs and AACG, except two case reports. We aimed to investigate whether BZDs increase the risk of AACG in a geriatric population.

METHODS

We performed a case-control study using a geriatric cohort from the National Health Insurance database (2002-2013) in Korea. Case subjects (n = 1117) were patients diagnosed with AACG. Controls, people who have not been diagnosed with AACG, were randomly matched with the case according to age, sex, and index year (n = 4468). To examine the risk of BZD use for AACG, we performed conditional logistic regression analyses with potential confounders including comorbidities and concomitant medication.

RESULTS

The use of BZD within 30 days was not significantly associated with AACG risk (adjusted odds ratio [aOR] = 1.14, 95% confidence interval [CI] = 0.94-1.37). Further analyses showed that, compared with non-use of BZD, new BZD use had a significantly increased risk for the development of AACG (aOR = 1.62, 95% CI = 1.09-2.37). The risk was higher in the new BZD users exposed within 7 days (aOR = 3.09, 95% CI = 1.58-5.88).

CONCLUSION

We found that BZDs increase the risk of AACG at the beginning of its use among the Korean elderly. Clinicians should monitor visual disturbance in the elderly during the early period after prescription of BZD.

The Effects of Natural Daylight on Length of Hospital Stay

BACKGROUND AND PURPOSE

While providing medical services, hospitals generate many data about patients. Such medical data could contribute to better treatments once their associations or patterns have been identified. With properly analyzed medical data, traditional knowledge at an individual level could be further extended to broader populations. This comprehensive study was performed to demonstrate the effectiveness of light using medical data accumulated over 15 years.

METHODS

Patients who were admitted to the window or door side of a six-bedded room were included. Patients admitted to the emergency room and elderly people aged >80 years were excluded. Patients' length of stay was compared per what bed they were in (excluding middle beds). A multiple regression analysis was performed with patients admitted to the window or door side to determine whether the window affected their hospital stay. In addition, a multiple regression analysis was performed after adjusting for confounders by 1:1 matching between the two groups (ie, age, sex, and admitting department).

RESULTS

Participants were 38 788 patients with a bed near the window and 46 233 patients with a bed near the door. Results revealed that patients' length of stay was shorter for those near the window compared with those near the door, which was also true after group matching (33 921 participants in each group).

CONCLUSIONS

Clinical trials that test evidence-based designs of physical environments in wards or hospital rooms are usually difficult to perform. As an alternative strategy, using accumulated electronic medical data, we assessed this key element of hospital design.

Standard-based comprehensive detection of adverse drug reaction signals from nursing statements and laboratory results in electronic health records

Objective. We propose 2 Medical Dictionary for Regulatory Activities–enabled pharmacovigilance algorithms, MetaLAB and MetaNurse, powered by a per-year meta-analysis technique and improved subject sampling strategy.

Matrials and methods. This study developed 2 novel algorithms, MetaLAB for laboratory abnormalities and MetaNurse for standard nursing statements, as significantly improved versions of our previous electronic health record (EHR)–based pharmacovigilance method, called CLEAR. Adverse drug reaction (ADR) signals from 117 laboratory abnormalities and 1357 standard nursing statements for all precautionary drugs (n  = 101) were comprehensively detected and validated against SIDER (Side Effect Resource) by MetaLAB and MetaNurse against 11 817 and 76 457 drug-ADR pairs, respectively.

Results. We demonstrate that MetaLAB (area under the curve, AUC = 0.61 ± 0.18) outperformed CLEAR (AUC = 0.55 ± 0.06) when we applied the same 470 drug-event pairs as the gold standard, as in our previous research. Receiver operating characteristic curves for 101 precautionary terms in the Medical Dictionary for Regulatory Activities Preferred Terms were obtained for MetaLAB and MetaNurse (0.69 ± 0.11; 0.62 ± 0.07), which complemented each other in terms of ADR signal coverage. Novel ADR signals discovered by MetaLAB and MetaNurse were successfully validated against spontaneous reports in the US Food and Drug Administration Adverse Event Reporting System database.

Discussion. The present study demonstrates the symbiosis of laboratory test results and nursing statements for ADR signal detection in terms of their system organ class coverage and performance profiles.

Conclusion. Systematic discovery and evaluation of the wide spectrum of ADR signals using standard-based observational electronic health record data across many institutions will affect drug development and use, as well as postmarketing surveillance and regulation.

Analysis of the number of enlarged pores according to site, age, and sex

BACKGROUND

Increasing the number of enlarged pores causes cosmetic problems. The difference in the number of enlarged pores according to facial site, age, and sex is unclear.

OBJECTIVE

To analyze the distribution of the number of enlarged pores according to facial site, age, and sex.

METHODS AND MATERIALS

We analyzed the number of the enlarged pores and the percentage of wrinkles in the nose, forehead, and cheek from 434 polarized images. The measurement results were analyzed according to site, age, and sex. Relationship between enlarged pore counts and wrinkle severity was also analyzed. The study was conducted by using DermaVision,™ which can take cross-polarization, parallel polarization, and ultraviolet light images.

RESULTS

The enlarged pores of the nose and forehead were more prominent than in the cheeks. Pore counts were increased with age, and the increment was significant between the 30's and 40's. There was no significant difference by gender. Enlarged pore counts were related to wrinkle severity.

CONCLUSIONS

The number of enlarged pores differs depending on body site and increased with age. The enlarged pore counts correlate with wrinkle severity and the correlation varies depending on the body site.

Conversion and Data Quality Assessment of Electronic Health Record Data at a Korean Tertiary Teaching Hospital to a Common Data Model for Distributed Network Research

OBJECTIVES

A distributed research network (DRN) has the advantages of improved statistical power, and it can reveal more significant relationships by increasing sample size. However, differences in data structure constitute a major barrier to integrating data among DRN partners. We describe our experience converting Electronic Health Records (EHR) to the Observational Health Data Sciences and Informatics (OHDSI) Common Data Model (CDM).

METHODS

We transformed the EHR of a hospital into Observational Medical Outcomes Partnership (OMOP) CDM ver. 4.0 used in OHDSI. All EHR codes were mapped and converted into the standard vocabulary of the CDM. All data required by the CDM were extracted, transformed, and loaded (ETL) into the CDM structure. To validate and improve the quality of the transformed dataset, the open-source data characterization program ACHILLES was run on the converted data.

RESULTS

Patient, drug, condition, procedure, and visit data from 2.07 million patients who visited the subject hospital from July 1994 to November 2014 were transformed into the CDM. The transformed dataset was named the AUSOM. ACHILLES revealed 36 errors and 13 warnings in the AUSOM. We reviewed and corrected 28 errors. The summarized results of the AUSOM processed with ACHILLES are available at http://ami.ajou.ac.kr:8080/.

CONCLUSIONS

We successfully converted our EHRs to a CDM and were able to participate as a data partner in an international DRN. Converting local records in this manner will provide various opportunities for researchers and data holders.

New Alert Override Codes for the Drug Utilization Review System Derived from Outpatient Prescription Data from a Tertiary Teaching Hospital in Korea

Objectives

This paper proposes new alert override reason codes that are improvements on existing Drug Utilization Review (DUR) codes based on an analysis of DUR alert override cases in a tertiary medical institution.

Methods

Data were obtained from a tertiary teaching hospital covering the period from April 1, 2012 to January 15, 2013. We analyzed cases in which doctors had used the 11 overlapping prescription codes provided by the Health Insurance Review and Assessment Service (HIRA) or had provided free-text reasons.

Results

We identified 27,955 alert override cases. Among these, 7,772 (27.8%) utilized the HIRA codes, and 20,183 (72.2%) utilized free-text reasons. According to the free-text content analysis, 8,646 cases (42.8%) could be classified using the 11 HIRA codes, and 11,537 (57.2%) could not. In the unclassifiable cases, we identified the need for codes for "prescription relating to operation" and "emergency situations." Two overlapping prescription codes required removal because they were not used. Codes A, C, F, H, I, and J (for drug non-administration cases) explained surrounding situations in too much detail, making differentiation between them difficult. These 6 codes were merged into code J4: "patient was not taking/will not take the medications involved in the DDI." Of the 11 HIRA codes, 6 were merged into a single code, 2 were removed, and 2 were added, yielding 6 alert override codes. We could codify 23,550 (84.2%) alert override cases using these codes.

Conclusions

These new codes will facilitate the use of the drug–drug interactions alert override in the current DUR system. For further study, an appropriate evaluation should be conducted with prescribing clinicians.

A normalization method for combination of laboratory test results from different electronic healthcare databases in a distributed research network

PURPOSE

Distributed research networks (DRNs) afford statistical power by integrating observational data from multiple partners for retrospective studies. However, laboratory test results across care sites are derived using different assays from varying patient populations, making it difficult to simply combine data for analysis. Additionally, existing normalization methods are not suitable for retrospective studies. We normalized laboratory results from different data sources by adjusting for heterogeneous clinico-epidemiologic characteristics of the data and called this the subgroup-adjusted normalization (SAN) method.

METHODS

Subgroup-adjusted normalization renders the means and standard deviations of distributions identical under population structure-adjusted conditions. To evaluate its performance, we compared SAN with existing methods for simulated and real datasets consisting of blood urea nitrogen, serum creatinine, hematocrit, hemoglobin, serum potassium, and total bilirubin. Various clinico-epidemiologic characteristics can be applied together in SAN. For simplicity of comparison, age and gender were used to adjust population heterogeneity in this study.

RESULTS

In simulations, SAN had the lowest standardized difference in means (SDM) and Kolmogorov-Smirnov values for all tests (p < 0.05). In a real dataset, SAN had the lowest SDM and Kolmogorov-Smirnov values for blood urea nitrogen, hematocrit, hemoglobin, and serum potassium, and the lowest SDM for serum creatinine (p < 0.05).

CONCLUSION

Subgroup-adjusted normalization performed better than normalization using other methods. The SAN method is applicable in a DRN environment and should facilitate analysis of data integrated across DRN partners for retrospective observational studies.

A quantitative method for assessment of prescribing patterns using electronic health records

Background

Most available quality indicators for hospitals are represented by simple ratios or proportions, and are limited to specific events. A generalized method that can be applied to diverse clinical events has not been developed. The aim of this study was to develop a simple method of evaluating physicians' prescription patterns for diverse events and their level of awareness of clinical practice guidelines.

Methods and Findings

We developed a quantitative method called Prescription pattern Around Clinical Event (PACE), which is applicable to electronic health records (EHRs). Three discrete prescription patterns (intervention, maintenance, and discontinuation) were determined based on the prescription change index (PCI), which was calculated by means of the increase or decrease in the prescription rate after a clinical event. Hyperkalemia and Clostridium difficile-associated diarrhea (CDAD) were used as example cases. We calculated the PCIs of 10 drugs related to hyperkalemia, categorized them into prescription patterns, and then compared the resulting prescription patterns with the known standards for hyperkalemia treatment. The hyperkalemia knowledge of physicians was estimated using a questionnaire and compared to the prescription pattern. Prescriptions for CDAD were also determined and compared to clinical knowledge. Clinical data of 1698, 348, and 1288 patients were collected from EHR data. The physicians prescribing behaviors for hyperkalemia and CDAD were concordant with the standard knowledge. Prescription patterns were well correlated with individual physicians' knowledge of hyperkalemia (κ = 0.714). Prescribing behaviors according to event severity or clinical condition were plotted as a simple summary graph.

Conclusion

The algorithm successfully assessed the prescribing patterns from the EHR data. The prescription patterns were well correlated with physicians' knowledge. We expect that this algorithm will enable quantification of prescribers' adherence to clinical guidelines and be used to facilitate improved prescribing practices.

Airway management using a supraglottic airway device without endotracheal intubation for positive ventilation of anaesthetized rats

Endotracheal intubation is often necessary for positive pressure ventilation of rats during open thoracic surgery. Since endotracheal intubation in rats is technically difficult and is associated with numerous complications, many techniques using various devices have been described in the scientific literature. In this study, we compared the effectiveness of airway management of a home-made supraglottic airway device (SAD), which is cheap to fabricate and easy to place with that of an endotracheal intubation tube in enflurane-anaesthetized rats. Twenty male Sprague-Dawley rats (200-300 g) were randomly assigned to two equal groups for positive pressure mechanical ventilation using either the SAD or an endotracheal intubation tube. The carotid artery of each rat was cannulated for continuous blood pressure measurements and obtaining blood samples for determination of oxygen tension, carbon dioxide tension, and blood acidity before, during and after SAD placement or endotracheal intubation. Proper placement of the SAD was confirmed by observing chest wall movements that coincided with the operation of the mechanical ventilator. No complications and adverse events were encountered in the rats in which the SAD was placed, during SAD placement and immediate removal, during their mechanical ventilation through the SAD, and one week after SAD removal. From the results of blood gas analyses, we conclude that anaesthetized rats can be successfully ventilated using an SAD for open thoracic surgery.

Monitoring physicians' prescription patterns on electronic health record: the prescription pattern around clinical event (PACE) algorithm

Electronic health records (EHRs) have gained attention as a valuable data source for medical research, as its adoption rate continues to rise. However, no method for the monitoring of physicians' prescription patterns has been established. Since EHR maintain all prescription data as well as clinical events that occur during the care of patients, we hypothesized that a physician's prescription pattern can be monitored from EHR. In this study, we developed a novel algorithm named PACE, Prescription pattern Around Clinical Event. This algorithm analyzes distribution of the prescription of specific drugs around the time of a clinical event. In the proof of concept study, prescription changes with regard to hyperkalemia were well represented by the algorithm, and the observed patterns well correlated with the physician's knowledge on hyperkalemia (Cohen's kappa, 0.457-0.653). We expect that this algorithm can be used to monitor the guideline adherence of physicians.

Comparison of hyperkalemic risk in hospitalized patients treated with different angiotensin receptor blockers: a retrospective cohort study using a Korean clinical research database

BACKGROUND AND AIM

Clinical use of angiotensin II type 1 receptor antagonists (angiotensin receptor blockers [ARBs]) is associated with hyperkalemia as an adverse drug reaction. Although it has significant clinical implications, the incidence and relative risks of hyperkalemia with various ARBs have not yet been fully evaluated. The purpose of this study was to determine the risk of hyperkalemic events in hospitalized patients treated with different ARBs and to compare the risk among them.

METHODS

We constructed a retrospective cohort composed of hospitalized adult patients who took ARBs in a single tertiary teaching hospital between April 2004 and March 2010. We estimated the incidence of hyperkalemia (serum potassium level >5.5 mEq/L) with various ARBs, and then compared the risk between them using a multivariate Cox proportional hazard model based on age, sex, Charlson co-morbidity score, baseline serum potassium, underlying diseases, and concomitant drugs.

RESULTS

We identified 6992 evaluable intervals from 5449 patients treated with one of the seven ARBs during hospitalization over the 71-month study period with 2521.6 patient-months. We found 381 hyperkalemic events (5.4%) during the study period and an overall event rate of 15.1/100 patient-months. Moderate to fatal hyperkalemia was relatively rare (>6.0 mEq/L, 2.1% [moderate]; >6.5 mEq/L, 0.9% [severe]; >7.0 mEq/L, 0.3% [fatal]). After adjustment for covariates, telmisartan showed a lower risk of hyperkalemia (hazard ratio 0.67; 95% confidence interval 0.51, 0.89) compared with all other ARBs.

CONCLUSION

The risk of hyperkalemic events in hospitalized patients treated with different ARBs was defined. Telmisartan showed a relatively lower hyperkalemic risk profile in hospitalized patients compared with other ARBs.

Construction of an open-access QT database for detecting the proarrhythmia potential of marketed drugs: ECG-ViEW

Information about the QT interval from surface electrocardiograms (ECGs) is essential for surveillance of the proarrhythmia potential of marketed drugs. However, ECG records obtained in daily practice cannot be easily used for this purpose without labor-intensive manual effort. This study was aimed at constructing an open-access QT database, the Electrocardiogram Vigilance with Electronic Data Warehouse (ECG-ViEW). This longitudinal observational database contains 710,369 measurements of QT and associated clinical data from 371,401 patients. The de-identified database is freely available at http://www.ecgview.org.

Development of novel breast cancer recurrence prediction model using support vector machine

Purpose

The prediction of breast cancer recurrence is a crucial factor for successful treatment and follow-up planning. The principal objective of this study was to construct a novel prognostic model based on support vector machine (SVM) for the prediction of breast cancer recurrence within 5 years after breast cancer surgery in the Korean population, and to compare the predictive performance of the model with the previously established models.

Methods

Data on 679 patients, who underwent breast cancer surgery between 1994 and 2002, were collected retrospectively from a Korean tertiary teaching hospital. The following variables were selected as independent variables for the prognostic model, by using the established medical knowledge and univariate analysis: histological grade, tumor size, number of metastatic lymph node, estrogen receptor, lymphovascular invasion, local invasion of tumor, and number of tumors. Three prediction algorithms, with each using SVM, artificial neural network and Cox-proportional hazard regression model, were constructed and compared with one another. The resultant and most effective model based on SVM was compared with previously established prognostic models, which included Adjuvant! Online, Nottingham prognostic index (NPI), and St. Gallen guidelines.

Results

The SVM-based prediction model, named 'breast cancer recurrence prediction based on SVM (BCRSVM),' proposed herein outperformed other prognostic models (area under the curve=0.85, 0.71, 0.70, respectively for the BCRSVM, Adjuvant! Online, and NPI). The BCRSVM evidenced substantially high sensitivity (0.89), specificity (0.73), positive predictive values (0.75), and negative predictive values (0.89).

Conclusion

As the selected prognostic factors can be easily obtained in clinical practice, the proposed model might prove useful in the prediction of breast cancer recurrence. The prediction model is freely available in the website (http://ami.ajou.ac.kr/bcr/).

A novel algorithm for detection of adverse drug reaction signals using a hospital electronic medical record database

PURPOSE

Quantitative analytic methods are being increasingly used in postmarketing surveillance. However, currently existing methods are limited to spontaneous reporting data and are inapplicable to hospital electronic medical record (EMR) data. The principal objectives of this study were to propose a novel algorithm for detecting the signals of adverse drug reactions using EMR data focused on laboratory abnormalities after treatment with medication, and to evaluate the potential use of this method as a signal detection tool.

METHODS

We developed an algorithm referred to as the Comparison on Extreme Laboratory Test results, which takes an extreme representative value pair according to the types of laboratory abnormalities on the basis of each patient's medication point. We used 10 years' EMR data from a tertiary teaching hospital, containing 32,033,710 prescriptions and 115,241,147 laboratory tests for 530,829 individual patients. Ten drugs were selected randomly for analysis, and 51 laboratory values were matched. The sensitivity, specificity, positive predictive value, and negative predictive value of the algorithm were calculated.

RESULTS

The mean number of detected laboratory abnormality signals for each drug was 27 (±7.5). The sensitivity, specificity, positive predictive value, and negative predictive value of the algorithm were 64-100%, 22-76%, 22-75%, and 54-100%, respectively.

CONCLUSION

The results of this study demonstrated that the Comparison on Extreme Laboratory Test results algorithm described herein was extremely effective in detecting the signals characteristic of adverse drug reactions. This algorithm can be regarded as a useful signal detection tool, which can be routinely applied to EMR data.

The first detection of Brucella canis in cattle in the Republic of Korea

Twenty mammary lymph node samples were collected from cattle on a farm in the Republic of Korea. These cattle were serologically negative for Brucella by tube agglutination test (≤ 1:50) and serum agglutination test (≤ 1:50). Out of 20 lymph node samples, two samples were positive for Brucella growth on Brucella agar as well as blood agar. Tests for urease, hydrogen sulphide and reactions against monospecific sera A and M indicated that these two isolates (No. 15 and 16) belong to the genus Brucella. Genus specific, AMOS (abortus, melitensis, ovis, suis) and Bruce-ladder multiplex polymerase chain reaction (PCR) assays confirmed the Brucella isolates as either a B. abortus or a B. canis strain. This is the first report of the occurrence of a B. canis infection in cattle in Korea. More survey data are needed to determine whether B. canis is a significant aetiology in the cases of cattle brucellosis in Korea.

An Automated Measurement of Ciliary Beating Frequency using a Combined Optical Flow and Peak Detection

Objectives

The mucociliary transport system is a major defense mechanism of the respiratory tract. The performance of mucous transportation in the nasal cavity can be represented by a ciliary beating frequency (CBF). This study proposes a novel method to measure CBF by using optical flow.

Methods

To obtain objective estimates of CBF from video images, an automated computer-based image processing technique is developed. This study proposes a new method based on optical flow for image processing and peak detection for signal processing. We compare the measuring accuracy of the method in various combinations of image processing (optical flow versus difference image) and signal processing (fast Fourier transform [FFT] vs. peak detection [PD]). The digital high-speed video method with a manual count of CBF in slow motion video play, is the gold-standard in CBF measurement. We obtained a total of fifty recorded ciliated sinonasal epithelium images to measure CBF from the Department of Otolaryngology. The ciliated sinonasal epithelium images were recorded at 50-100 frames per second using a charge coupled device camera with an inverted microscope at a magnification of ×1,000.

Results

The mean square errors and variance for each method were 1.24, 0.84 Hz; 11.8, 2.63 Hz; 3.22, 1.46 Hz; and 3.82, 1.53 Hz for optical flow (OF) + PD, OF + FFT, difference image [DI] + PD, and DI + FFT, respectively. Of the four methods, PD using optical flow showed the best performance for measuring the CBF of nasal mucosa.

Conclusions

The proposed method was able to measure CBF more objectively and efficiently than what is currently possible.

Analysis of Relationship between Levofloxacin and Corrected QT Prolongation Using a Clinical Data Warehouse

Objective

The aim of this study was to examine whether or not levofloxacin has any relationship with QT prolongation in a real clinical setting by analyzing a clinical data warehouse of data collected from different hospital information systems.

Methods

Electronic prescription data and medical charts from 3 different hospitals spanning the past 9 years were reviewed, and a clinical data warehouse was constructed. Patients who were both administrated levofloxacin and given electrocardiograms (ECG) were selected. The correlations between various patient characteristics, concomitant drugs, corrected QT (QTc) prolongation, and the interval difference in QTc before and after levofloxacin administration were analyzed.

Results

A total of 2,176 patients from 3 different hospitals were included in the study. QTc prolongation was found in 364 patients (16.7%). The study revealed that age (OR 1.026, p < 0.001), gender (OR 0.676, p = 0.007), body temperature (OR 1.267, p = 0.024), and cigarette smoking (OR 1.641, p = 0.022) were related with QTc prolongation. After adjusting for related factors, 12 drugs concomitant with levofloxacin were associated with QTc prolongation. For patients who took ECGs before and after administration of levofloxacin during their hospitalization (n = 112), there was no significant difference in QTc prolongation.

Conclusions

The age, gender, body temperature, cigarette smoking and various concomitant drugs might be related with QTc prolongation. However, there was no definite causal relationship or interaction between levofloxacin and QTc prolongation. Alternative surveillance methods utilizing the massive accumulation of electronic medical data seem to be essential to adverse drug reaction surveillance in future.

Fraudulent retouching of digital radiographic images--a potential risk

AIM

To determine whether radiologists can recognize images retouched to include sham lesions.

MATERIALS AND METHODS

Ten representative key images were selected of aortic dissection, hepatocellular carcinoma, renal cell carcinoma, colon cancer, liver metastasis, hepatic cyst, gallbladder stones, splenic artery aneurysm, adrenal adenoma, and stomach cancer from abdominal computed tomography (CT) imaging performed in 2008. Five of the key images were replaced with retouched images using image-editing software. The time to complete retouching was recorded for each image. Radiologists were requested to make a diagnosis for the 10 images, and were then asked to identify possible retouched images. The time taken to reach a decision in each case was recorded. Thirty radiologists (13 residents and 17 attending radiologists) participated as reviewers.

RESULTS

The time to complete retouching was 15.2±3.15 min. None of the reviewers recognized that some images were retouched during diagnosis. The rate of correct diagnosis was 90% (range 71.7-100%). After reviewers were informed of possible image retouching, the detection rate of retouched images was 50% (40-58.3%). This rate was statistically the same as random choice (p=0.876). There was no significant difference between residents and attending radiologists in the detection rate of retouched images (p=0.786). The time to diagnosis and the time to detection of the retouched images were 15 (14-17) and 6 (5-7) min, respectively.

CONCLUSION

Digital images can be easily retouched, and radiologists have difficulty in identifying retouched images. Radiologists should be aware of the potential fraudulent use of retouched images.

Inhibition of Orientia tsutsugamushi infection by a truncated recombinant 56-kDa outer membrane protein

AIMS

The objective of this study was to evaluate recombinant 56-kDa outer membrane protein as a potential inhibitor to infection from Orientia tsutsugamushi.

METHODS AND RESULTS

The 56-kDa protein was cloned and expressed in an Escherichia coli system, and the degree of target cell attachment to immobilized 56-kDa protein was measured in a cell adhesion assay. The results showed that the 56-kDa protein has an ability to attach HeLa cells. Furthermore, treatment of target cells with a truncated 56-kDa 1-418 (amino acid residues) protein inhibited target cell infection by O. tsutsugamushi, demonstrated with an indirect immunofluorescence antibody assay.

CONCLUSIONS

The truncated 56-kDa protein (a.a. 1-418) plays an important role in O. tsutsugamushi infection, and the 56-kDa protein could be useful and effective in the inhibition of O. tsutsugamushi attachment and infection.

SIGNIFICANCE AND IMPACT OF THE STUDY

The attachment of the 56-kDa protein to target cells was directly determined by in vitro adherence test, and the invasion of target cells by O. tsutsugamushi was inhibited by treating the target cells with a truncated 56-kDa protein.

Adoptive immunotherapy using human peripheral blood lymphocytes transferred with RNA encoding Her-2/neu-specific chimeric immune receptor in ovarian cancer xenograft model

The current gene transfer technology for single chain (scFv)-based chimeric immune receptor (CIR) has relied on retrovirus and lentivirus vectors which require a long time to obtain sufficient number of transduced cells and stably incorporate into genome. To ameliorate these limitations, we applied RNA electroporation to human peripheral blood lymphocytes (PBLs) activated with anti-CD3 antibody and interleukin-2 (IL-2) for 3 days and assessed that PBL transiently expressing anti-Her-2/neu CIR (CIR-PBL) containing signaling portion of CD28 and CD3zeta could elicit strong cytotoxicity in vitro and antitumor responses in vivo. The CIR-PBL expressed high level of CIR in CD4+, CD8+ and CD56+ cells. Her-2/neu-specific stimulation induced secretion of type-I cytokines including interferon-gamma (IFN-gamma), IL-8 and granulocyte-macrophage colony-stimulating factor, and IFN-gamma secretion was mainly mediated by CD8+ T cells. CIR-PBL specifically killed SKOV3 cell line expressing Her-2/neu. Adoptive transfer of CIR-PBL in SKOV3 xenograft model led to significant inhibition of tumor growth compared with transfer of mock-transduced PBL and showed higher inhibition than those with Herceptin, humanized monoclonal antibody specific for Her-2/neu. These results provided evidence that electroporation of CIR RNA to human PBLs could be used for rapid generation and high number of therapeutic antigen-specific T cells for adoptive immunotherapy.

Coexistence of ductal constriction and closure of the foramen ovale in utero

We report a fetus with an unusual combination of a narrow ductus arteriosus (DA) and foramen ovale. A pregnant mother was referred at 26 weeks of gestation for fetal pericardial effusion. Fetal echocardiography showed pericardial effusion, right atrial enlargement, right ventricular hypertrophy, and tricuspid regurgitation. The DA looked tortuous with S-shaped kinking. The atrial septum primum bulged into the left atrium. Color Doppler did not show any flow across the atrial septum. Cesarean section was performed at 31 weeks of gestation. Admission to intensive care was required after delivery, but the infant gradually improved and was discharged home without any sequela.

Cisplatin-induced apoptosis by translocation of endogenous Bax in mouse collecting duct cells

cis-platinum(II) (cis-diammine dichloroplatinum; cisplatin) is a potent antitumor compound that is widely used for the treatment of many malignancies. An important side-effect of cisplatin is nephrotoxicity, which results from injury to renal tubular epithelial cells and can be manifested as either acute renal failure or a chronic syndrome characterized by renal electrolyte wasting. Recently, apoptosis has been recognized as an important mechanism of cell death mediating the antitumor effect of cisplatin. This study was undertaken to examine the mechanisms of cell death induced by cisplatin in M-1 cells, which were derived from the outer cortical collecting duct cells of SV40 transgenic mice. Treatment of M-1 cells with high concentrations of cisplatin (0.5 and 1 mM) for 2 hr led to necrotic cell death, whereas a 24-hr treatment with 5-20 microM cisplatin led to apoptosis. Antioxidants protected against cisplatin-induced necrosis, but not apoptosis, indicating that reactive oxygen species play a role in mediating necrosis but not apoptosis induced by cisplatin and that the mechanism of cell death induced by cisplatin is concentration dependent. The low concentrations of cisplatin, which induced apoptosis in M-1 cells, did not affect the expression levels of Bcl-2-related proteins and did not activate c-Jun NH2-terminal kinase (SAPK/JNK). Cisplatin induced the translocation of endogenous Bax from the cytosolic to the membrane fractions and, subsequently, the release of cytochrome c. Overexpression of Bcl-2 blocked cisplatin-induced apoptosis and Bax translocation. These observations suggest that the subcellular redistribution of Bax is a critical event in the apoptosis induced by cisplatin.

The behavior of a poly(aniline) solid contact pH selective electrode based on N,N,N',N'-tetrabenzylethanediamine ionophore

A hydrogen ion-selective solid-contact electrode based on N,N,N',N'-tetrabenzylethanediamine has shown the best Nernstian slope and selectivity and the widest response range in a Tris buffered pH sample solution. Its linear dynamic range was pH 3.50-11.94, and the Nernstian slope showed 52.1 mV/pH (at 20 +/- 0.2 degrees C). When it was directly applied to human whole blood (in pH range 6.0-8.5) we could obtain the same satisfying results. This electrode continuously contacted a Tris 7.47 buffered solution, human whole blood and a hydrofluoric acid solution for one month without any loss of performance. Also, hydrofluoric acid did not influence the surface of this electrode, and thus it was maintained without showing any changes in potentials after being used in a hydrofluoric acid solution. The standard deviation in the determined e.m.f. differences was 1.5 mV (N = 5) for Tris buffer solutions of pH 6.5 and 1.1 mV at a Tris buffer solutions of pH 8.5. The 90% response time of the electrodes obtained by injecting of hydrochloric acid into the Tris buffer sample solution was less than 10 s. Especially, in the this paper, with these potential response characteristics of hydrogen ion selective poly(aniline) solid contact electrode, we have also presented the pH response mechanism of this electrode and the role of poly(aniline) and a doped anion in a poly(aniline) layer.

Hormonal cross-talk between auxin and ethylene differentially regulates the expression of two members of the 1-aminocyclopropane-1-carboxylate oxidase gene family in rice (Oryza sativa L.)

Two cDNA clones, pOS-ACO2 and pOS-ACO3, encoding 1-aminocyclopropane-1-carboxylate (ACC) oxidase were isolated from rice seedling cDNA library. pOS-ACO3 is a 1,299 bp full-length clone encoding 321 amino acids (Mr=35.9 kDa), while pOS-ACO2 is 1,072 bp long and is a partial cDNA clone encoding 314 amino acids. These two deduced amino acid sequences share 70% identity, and display a high degree of sequence identity (72-92%) with previously isolated pOS-ACO1 of deepwater rice. The chromosomal location studies show that OS-ACO2 is positioned on the long arm of chromosome 9, while OS-ACO3 on the long arm of chromosome 2 of rice genome. A marked increase in the level of OS-ACO2 transcript was observed in IAA-treated etiolated rice seedlings, whereas the OS-ACO3 mRNA was greatly accumulated by ethylene treatment. Results of ethylene inhibitor studies indicated that auxin promotion of the OS-ACO2 transcription was not mediated through the action of auxin-induced ethylene. Thus, it appears that there are two groups of ACC oxidase transcripts in rice plants, either auxin-induced or ethylene-induced. The auxin-induced OS-ACO2 expression was partially inhibited by ethylene, while ethylene induction of OS-ACO3 transcription was completely blocked by auxin. These results indicate that the expression of ACC oxidase genes is regulated by complex hormonal networks in a gene specific manner in rice seedlings. Okadaic acid, a potent inhibitor of protein phosphatase, effectively suppressed the IAA induction of OS-ACO2 expression, suggesting that protein dephosphorylation plays a role in the induction of ACC oxidase by auxin. A scheme of the multiple regulatory pathways for the expression of ACC oxidase gene family by auxin, ethylene and protein phosphatase is presented.

Botulinum toxin A for the treatment of facial hyperkinetic wrinkle lines in Koreans

There are a number of different causes for facial wrinkle lines, such as aging, gravity, and chronic pulling of mimetic muscles on the face. Among these, pulling by mimetic muscles on the skin not only involves facial expression but also has a great role in forming facial wrinkle lines as a result of repetitive action, such as dynamic or hyperkinetic wrinkle lines. Botulinum toxin A is currently being used for eliminating facial hyperkinetic wrinkles by causing paralysis of the underlying mimetic muscles. Because there are some histologic differences between Asians and Caucasians, such as thick dermis and more abundant collagen fiber, etc., the chronic pulling by mimetic muscles on the skin is expected to affect facial wrinkles differently. Therefore, the purpose of this study was to determine the efficacy of botulinum toxin A injection in eliminating facial hyperkinetic wrinkle lines among Korean patients. This study included 38 patients and 59 injection sessions from January of 1996 to April of 1997. We used Botox containing 100 U. Toxin was diluted with 4 ml of sterile normal saline and yielded 2.5 U for each 0.1 cc. A dose of 5 to 10 U was used in each muscle. Ages ranged from 26 to 56 years. There were 33 women and 5 men included in this study. Thirty-two of the patients were followed from 3 months up to 12 months after injections. The number of injection sessions that were performed on each patient was as follows: one session, 23 patients; two sessions, 10 patients; three sessions, 4 patients; four sessions, 1 patient. The number of injections per target site among these 38 patients was as follows: lateral canthal area, 33; glabellar area, 9; forehead, 9; nasal dorsum, 5. The most common duration of effective response was about 4 months, but in eight patients the period was over 5 months. After the response, complete recovery took about 1 or 2 months. Two patients felt unsatisfied, 5 patients felt slightly improved, and 25 patients retained only a slight line and were satisfied with the results. None of the patients experienced complete removal of wrinkle lines. Adverse effects included altered facial looks or appearances, mild local swelling, and ecchymosis at the injection sites. No systemic side effects were noted. Based on these results, the injection of botulinum toxin A seems to be an effective method of eliminating wrinkle lines on the upper third of the face in Korean patients, and it was a simple and effective nonsurgical procedure.

Apoptosis induced by inhibition of contact with extracellular matrix in mouse collecting duct cells

Cell-matrix interactions have major effects upon phenotypic features such as gene regulation, cytoskeletal structure, differentiation and aspects of cell growth control. Detachment from the matrix epithelial cells induces programmed cell death, and this cell detachment induced apoptosis has been referred to as 'anoikis'. This study was undertaken to determine whether apoptosis is induced by inhibition of contact with extracellular matrix (ECM) in collecting duct cells and to investigate the signaling mechanisms of the process. Upon detachment from ECM, mouse inner medullary collecting duct cells (mIMCD-3) and mouse outer cortical collecting duct cells (M-1), which were derived from an SV40 transgenic mouse, entered into programmed cell death. Forced suspension of mIMCD-3 or M-1 cells did not affect the expression of Bcl-2-related proteins and did not activate c-Jun NH(2)-terminal kinase. Detachment of cells from ECM activated p38 mitogen-activated protein kinase (p38), but its inhibition with SB203580 did not protect cells from anoikis. Detachment of cells from matrix inhibited NF-kappaB activity, and the inhibition of NF-kappaB activity by overexpression of nonphosphorylatable I-kappaB increased detachment-induced apoptotic cell death in M-1 cells. Forced suspension of M-1 cells still activated p53 activity. Caspase-8 was activated during anoikis, but the time course of its activation was in accordance with DNA fragmentation. These results indicate that detachment from ECM induces apoptosis in the kidney collecting duct cells. Changes in expression levels of Bcl-2-related proteins or activation of JNK/p38 kinase are not critical for anoikis. Decrease in NF-kappaB activity and activation of p53 induced by inhibition of interaction with ECM play roles in anoikis in SV-40-transformed collecting duct cells. Caspase-8 is activated during detachment-induced apoptosis, the mechanisms of which are independent of activation of cell death receptors.

Protection against hydrogen peroxide induced injury in renal proximal tubule cell lines by inhibition of poly(ADP-ribose) synthase

Radicals including superoxide anions, hydrogen peroxide or hydroxyl radicals and NO or peroxynitrite cause the breakage of DNA strands and activation of poly-(ADP-ribose) synthase (PARS). Recent studies showed that inhibition of PARS activity reduces the tissue injury after exposure to oxidative stress. However, the role of PARS in renal injury by oxidants has not been examined. In this study effect of a PARS inhibitor, 3-aminobenamide (3-AB), on injury of opossum kidney or LLC-PK(1) cells by hydrogen peroxide or tert-butyl hydroperoxide (t-BHP) was examined. The exposure of opossum kidney cells to hydrogen peroxide activated PARS and decreased cellular adenosine triphosphate levels in a concentration-dependent manner. Inhibition of PARS with 3-AB prevented the cell death induced by hydrogen peroxide and also prevented adenosine triphosphate depletion. 3-AB did not have hydroxyl radical scavenging effect. In contrast, t-BHP did not affect the PARS activity. The decrease in cellular adenosine triphosphate levels by t-BHP was less than that by hydrogen peroxide. 3-AB failed to prevent the cell death induced by t-BHP. PARS activation after exposure of hydrogen peroxide was inhibited by addition of t-BHP. However, t-BHP showed an additive effect on cell death with hydrogen peroxide. These results indicate that activation of PARS plays an important role in hydrogen peroxide induced injury in opossum kidney cells and that hydrogen peroxide and t-BHP induce cell injury by different mechanisms.

Inhibitory effects of chlorophyllin on 7,12-dimethylbenz[a]anthracene-induced bacterial mutagenesis and mouse skin carcinogenesis

Chlorophyllin (CHL), a water-soluble derivative of chlorophyll, has been used for the treatment of several abnormal human conditions without apparent toxicity. Recent studies have revealed that CHL has the excellent chemopreventive potential. In the present investigation, we have found the inhibitory activities of CHL against 7,12-dimethylbenz[a]anthracene (DMBA)-induced mutagenesis in Salmonella typhimurium TA100 and also on DMBA-initiated and 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-promoted mouse skin tumor formation. The incidence and the multiplicity of skin tumors were not significantly decreased in mice by a single topical application of CHL prior to the DMBA treatment, but there was a marked suppression of papillomagenesis in mice treated with CHL during the promotional stage. Furthermore, the formation of DMBA-induced papillomagenesis was reduced in all mice that had received CHL for 6 weeks following treatment with TPA for 6, 18 and 24 weeks. These results indicate that CHL can inhibit both tumor promotion and the progression of papillomagenesis in the two-stage mouse skin carcinogenesis induced by DMBA and TPA.

Rescue of cyclin D1 deficiency by knockin cyclin E

D-type cyclins and cyclin E represent two very distinct classes of mammalian G1 cyclins. We have generated a mouse strain in which the coding sequences of the cyclin D1 gene (Ccnd1) have been deleted and replaced by those of human cyclin E (CCNE). In the tissues and cells of these mice, the expression pattern of human cyclin E faithfully reproduces that normally associated with mouse cyclin D1. The replacement of cyclin D1 with cyclin E rescues all phenotypic manifestations of cyclin D1 deficiency and restores normal development in cyclin D1-dependent tissues. Thus, cyclin E can functionally replace cyclin D1. Our analyses suggest that cyclin E is the major downstream target of cyclin D1.

Expression of excitation-contraction coupling proteins during muscle differentiation

The goal of this study was to characterize three major excitation-contraction (E-C) coupling proteins: ryanodine receptor [RyR, the calcium release channel in the sarcoplasmic reticulum (SR)], dihydropyridine receptor (DHPR, the voltage-gated L-type calcium channel in the transverse tubule) and SR Ca2+-ATPase (SERCA, the calcium pump in the SR) in the differentiating primary cultures of rat skeletal and cardiac muscle cells. The expression levels of these proteins were determined by ligand binding assays and/ or immunoblottings along with an examination of the morphological changes in differentiating muscles by phase-contrast microscopy. In the skeletal cells, the expression levels of the E-C coupling proteins generally increased in the course of differentiation with the peak expression at the 9th day of culture. Simultaneous with the increased expression of the proteins, the myoblasts elongated, followed by alignment and fusion of the cells to form multinucleated myotubes. In the cardiac cells, on the contrary, the peak expression levels of DHPR, SERCA and RyR were reached within 2, 4, and 7 d of culture, respectively. Alignment of the cardiac muscle cells and spontaneous contraction occurred as early as several h after plating. These results suggest that expression patterns of E-C coupling proteins are different between skeletal and cardiac muscles, and that DHPR could play an important role in Ca2+ metabolism during the early stages of differentiation.

Synthetic peptides corresponding to various hydrophilic regions of the large subunit of cytochrome b558 inhibit superoxide generation in a cell-free system from neutrophils

Cytochrome b558 is a component of the superoxide-generating system in neutrophils and plays key roles in both the assembly of a functional complex with cytosolic proteins and shuttling an electron from NADPH to molecular oxygen. To determine the role of predicted hydrophilic domains of gp91-phox, a glycosylated subunit of the cytochrome, we synthesized peptides corresponding to the regions and tested whether they affected superoxide generation in the cell-free system obtained from human neutrophils. Among twelve peptides tested, six peptides, four of which correspond to previously unreported regions, inhibited superoxide generation in the cell-free system. All of the active peptides were effective when added to the system before activation with sodium dodecyl sulfate. Four peptides, including two peptides corresponding to two newly identified regions, inhibited the translocation of the cytosolic components, p47-phox and p67-phox. The extent of inhibition on translocation of these components varied depending on the peptide used.

Cyclin D2 is an FSH-responsive gene involved in gonadal cell proliferation and oncogenesis

THE D-type cyclins (D1, D2 and D3) are critical governors of the cell-cycle clock apparatus during the G1 phase of the mammalian cell cycle. These three D-type cyclins are expressed in overlapping, apparently redundant fashion in the proliferating tissues. To investigate why mammalian cells need three distinct D-type cyclins, we have generated mice bearing a disrupted cyclin D2 gene by using gene targeting in embryonic stem cells. Cyclin D2-deficient females are sterile owing to the inability of ovarian granulosa cells to proliferate normally in response to follicle-stimulating hormone (FSH), whereas mutant males display hypoplastic testes. In ovarian granulosa cells, cyclin D2 is specifically induced by FSH via a cyclic-AMP-dependent pathway, indicating that expression of the various D-type cyclins is under control of distinct intracellular signalling pathways. The hypoplasia seen in cyclin D2(-/-) ovaries and testes prompted us to examine human cancers deriving from corresponding tissues. We find that some human ovarian and testicular tumours contain high levels of cyclin D2 messenger RNA.

Beta subunit Glu-185 of Escherichia coli H(+)-ATPase (ATP synthase) is an essential residue for cooperative catalysis

Glu-beta 185 of the Escherichia coli H(+)-ATPase (ATP synthase) beta subunit was replaced by 19 different amino acid residues. The rates of multisite (steady state) catalysis of all the mutant membrane ATPases except Asp- beta 185 were less than 0.2% of the wild type one; the Asp- beta 185 enzyme exhibited 15% (purified) and 16% (membrane-bound) ATPase activity. The purified inactive Cys- beta 185 F1-ATPase recovered substantial activity after treatment with iodoacetate in the presence of MgCl2; maximal activity was obtained upon the introduction of about 3 mol of carboxymethyl residues/mol of F1. The divalent cation dependences of the S-carboxymethyl- beta 185 and Asp- beta 185 ATPase activities were altered from that of the wild type. The Asp- beta 185, Cys- beta 185, S-carboxymethyl-beta 185, and Gln- beta 185 enzymes showed about 130, 60, 20, and 50% of the wild type unisite catalysis rates, respectively. The S-carboxymethyl- beta 185 and Asp- beta 185 enzymes showed altered divalent cation sensitivities, and the S-carboxymethyl- beta 185 enzyme showed no Mg2+ inhibition. Unlike the wild type, the two mutant enzymes showed low sensitivities to azide, which stabilizes the enzyme Mg-ADP complex. These results suggest that Glu- beta 185 may form a Mg2+ binding site, and its carboxyl moiety is essential for catalytic cooperativity. Consistent with this model, the bovine glutamate residue corresponding to Glu- beta 185 is located close to the catalytic site in the higher order structure (Abrahams, J.P., Leslie, A.G.W., Lutter, R ., and Walker, J.E. (1994) Nature 370, 621-628)

Clinicopathologic significance of the K-ras gene codon 12 point mutation in stomach cancer. An analysis of 140 cases

BACKGROUND

The frequency and clinicopathologic significance of the K-ras gene point mutation in stomach cancer remain to be defined.

METHODS

The authors investigated the frequency of K-ras codon 12 point mutations in stomach cancer using a sensitive polymerase chain reaction (PCR)-based method in 140 samples and correlated the findings with various clinicopathologic characteristics of the patients.

RESULTS

The overall frequency of K-ras codon 12 point mutations in stomach cancer was 7.9% (11/140). DNA sequencing of nine cases with K-ras codon 12 point mutations identified seven cases with a single-base substitution of GGT to AGT (glycine to serine) and two with single-base substitution of GGT to AGT (aspartic acid). Tumors located in the upper third of the stomach had a significantly higher frequency of K-ras codon 12 mutations (3/8, 37.5%) compared with tumors located in the middle (4/29, 13.8%) or lower (3/99, 3.0%) thirds of the stomach (P = 0.001). No significant difference was observed in the frequency of K-ras codon 12 mutations in terms of other various clinicopathologic characteristics including tumor DNA ploidy and S-phase fraction. After a median follow-up of 26 months, disease free and overall survival were not significantly different between patients with stomach cancer with or without K-ras codon 12 mutation. Among eight patients with stomach cancer located in the upper part of the stomach, none of the three patients with K-ras gene-mutated tumors died versus four of five with tumors without K-ras gene mutations (P = 0.064).

CONCLUSIONS

K-ras codon 12 point mutations are uncommon in stomach cancer (7.9%). There was significant correlation between K-ras mutations and vertical tumor location in the stomach, suggesting that different mechanisms may play a role in the pathogenesis of stomach cancer according to the location of tumors in the stomach.

Clinicopathologic significance of the K-ras gene codon 12 point mutation in stomach cancer. An analysis of 140 cases

BACKGROUND

The frequency and clinicopathologic significance of the K-ras gene point mutation in stomach cancer remain to be defined.

METHODS

The authors investigated the frequency of K-ras codon 12 point mutations in stomach cancer using a sensitive polymerase chain reaction (PCR)-based method in 140 samples and correlated the findings with various clinicopathologic characteristics of the patients.

RESULTS

The overall frequency of K-ras codon 12 point mutations in stomach cancer was 7.9% (11/140). DNA sequencing of nine cases with K-ras codon 12 point mutations identified seven cases with a single-base substitution of GGT to AGT (glycine to serine) and two with single-base substitution of GGT to AGT (aspartic acid). Tumors located in the upper third of the stomach had a significantly higher frequency of K-ras codon 12 mutations (3/8, 37.5%) compared with tumors located in the middle (4/29, 13.8%) or lower (3/99, 3.0%) thirds of the stomach (P = 0.001). No significant difference was observed in the frequency of K-ras codon 12 mutations in terms of other various clinicopathologic characteristics including tumor DNA ploidy and S-phase fraction. After a median follow-up of 26 months, disease free and overall survival were not significantly different between patients with stomach cancer with or without K-ras codon 12 mutation. Among eight patients with stomach cancer located in the upper part of the stomach, none of the three patients with K-ras gene-mutated tumors died versus four of five with tumors without K-ras gene mutations (P = 0.064).

CONCLUSIONS

K-ras codon 12 point mutations are uncommon in stomach cancer (7.9%). There was significant correlation between K-ras mutations and vertical tumor location in the stomach, suggesting that different mechanisms may play a role in the pathogenesis of stomach cancer according to the location of tumors in the stomach.

Conserved Glu-181 and Arg-182 residues of Escherichia coli H(+)-ATPase (ATP synthase) beta subunit are essential for catalysis: properties of 33 mutants between beta Glu-161 and beta Lys-201 residues

Twenty-two mutants between beta Glu-161 and beta Lys-201 of Escherichia coli H(+)-ATPase beta subunit could grow by oxidative phosphorylation, but 11 other such mutants, beta Glu-181-->Gln, Asp, Asn, Thr, Ser, Ala, or Lys and beta Arg-182-->Lys, Ala, Glu, or Gln, could not. The beta Asp-181, beta Lys-182, and other defective mutants had 1.4, 1, and < 0.1%, respectively, of the wild-type membrane ATPase activity. Partially purified F1-ATPases from all mutants at positions 181 and 182, except for the beta Asp-181 and beta Lys-182 mutants, showed very low unisite catalysis. Purified F1-ATPases of the beta Gln-181 and beta Ala-181 mutants showed no multisite (or steady state) catalysis and slow unisite catalysis (< or = 1% of that of the wild type): their defects could be attributed to decreased catalytic rates (low k+2 and k-2). Changes of the k+2 and k-2 values in the beta Asp-181 enzyme, which showed detectable multi- and unisite catalysis, were less marked (27 and 21%, respectively, of wild-type rates). The beta Gln-182 enzyme showed defective catalysis (< or = 0.1% of the multi- and approximately 1% of the unisite catalyses of the wild type), whereas the beta Lys-182 enzyme showed 1 and 85% of the wild-type multisite and unisite catalytic rates, respectively. beta Lys-182 had wild-type values of k+2 and k-2, but beta Gln-182 had k+2 about 10-fold lower than that of wild type.(ABSTRACT TRUNCATED AT 250 WORDS)

Peptides corresponding to the region adjacent to His-94 in the small subunit of cytochrome b558 inhibit superoxide generation in a cell-free system from human neutrophils

Synthetic peptides corresponding to the region adjacent to His-94 in the small subunit of cytochrome b558 inhibited superoxide generation in a cell-free system. The shortest sequence that gave a half inhibitory concentration (IC50) lower than 50 microM was TRNYYVRAVL. Substitution of alanine for any of two tyrosine or central valine residues markedly increased IC50, thereby indicating that these residues are critical for the activity. Since the inhibition was observed when the peptide was added to the system before but not after the stimulation with sodium dodecylsulfate, the peptides seem to interact irreversibly with the cytochrome molecule and hinder electron transport or alternatively to interfere with the association between cytochrome b558 and cytosolic components.