Comparison of adhesive single-lead ECG device and Holter test for atrial fibrillation monitoring

Background

There is insufficient validation of diagnostic benefits of extended monitoring with an adhesive single-lead ECG device compared to Holter test for routine medical care of AF patients.

Purpose

The study aimed to compare AF detection rates between 72-hour monitoring using an adhesive single-lead ECG device (mobiCARE MC-100, Seers Technology, Republic of Korea) and 24-hour Holter test among AF patients at outpatient clinics.

Methods

A total of 200 AF patients indicated for Holter test at cardiology outpatient clinics enrolled in the study. Study participants equipped both Holter and MC-100 for the first 24 hours (Figure 1). After then, only MC-100 continued ECG monitoring for additional 48 hours. AF detection during the first 24 hours was compared between two devices. The diagnostic benefits of extended monitoring with MC-100 were evaluated.

Results

During the first 24 hours, both monitoring methods detected AF in the same 40/200 (20.0%) patients (20 patients with paroxysmal and persistent AF each). Compared to 24-hour Holter, MC-100 increased AF detection rate by 1.5-fold (58/200; 29.0%) and 1.6-fold (64/200; 32.0%) with 48- and 72-hour monitoring, respectively (Figure 2A). With MC-100, the number of newly discovered patients with paroxysmal AF was 20/44 (45.5%), 18/44 (40.9%), and 6/44 (13.6%) for 24-, 48-, and 72-hour monitoring. Compared to 24-hour Holter, 72-hour monitoring with MC-100 increased the detection rate of paroxysmal AF by 2.2-fold (44/20). If only the episodes lasting over 30 seconds were counted as AF with MC-100, the detection rate of paroxysmal AF was decreased by 9.1% (Figure 2B).

Conclusion

Compared to Holter, AF detection rates could be improved with an adhesive single-lead device, especially for patients with paroxysmal AF. This device is expected to be useful for AF detection among patients whose conventional ECG tests were ineffective in documenting AF episodes.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The Korea Medical Device Development Fund grant funded by the Korean government (the Ministry of Science and ICT, the Ministry of Trade, Industry and Energy, the Ministry of Health & Welfare, Republic of Korea, the Ministry of Food and Drug Safety)

The prevalence and risk factors of musculoskeletal disorders in the hands of fishermen working as oyster shuckers

OBJECTIVES

This study aimed to investigate the prevalence of musculoskeletal disorders in the hands and wrists of fishermen working as oyster shuckers, and to identify the risk factors associated with oyster shucking.

MATERIAL AND METHODS

A total of 590 fishery workers including those working as oyster shuckers in 2015-2017 were included in the study analysis. Hand osteoarthritis (OA), carpal tunnel syndrome (CTS), and ulnar impaction syndrome were diagnosed using X-ray, magnetic resonance imaging, and physical examinations according to each diagnostic criterion. The Rapid Entire Body Assessment was used as a measurement tool for analyzing the occupation-related burden factors.

RESULTS

The prevalence of hand OA, CTS, and ulnar impaction syndrome was higher in oyster shuckers than in aquaculture/offshore fishery workers. The prevalence of upper limb disease was higher in oyster shuckers than in other fishery workers, even in the prevalence of exposure to occupational burden factors. In oyster shuckers, the incidence of hand and wrist OA was 84%, that of CTS was 72%, and that of ulnar impaction syndrome was 41%. In addition, oyster shuckers were more likely to be exposed to occupational burden factors than were other types of fishermen.

CONCLUSIONS

The prevalence of hand OA, CTS, and ulnar impaction syndrome was higher in oyster shuckers. Therefore, proper stretching or exercises for rest and musculoskeletal relaxation, along with health-care education and promotion, will be needed for the fishermen's repeated posture and impact work. Int J Occup Med Environ Health. 2021;34(5):603-15.

Work-Related Risk Factors of Knee Meniscal Tears in Korean Farmers: A Cross-Sectional Study

Background

Meniscal tears are among the major risk factors for knee osteoarthritis progression. This study aimed to investigate the relationship between meniscal tears and work-related factors in the farming occupation.

Methods

The participants included 486 farmers (238 men and 248 women), aged 40–69 years, who were among the 550 farmers registered in the Korea Farmer's Knee Cohort (KFKC). Data such as those on gender, age, body mass index (BMI), mechanical axis, cumulative heavy-lifting working time (CLWT), cumulative squatting working time (CSWT), and previous knee injury history were collected from the questionnaire, along with whole leg radiographic findings. Two radiologists assessed the magnetic resonance images of both knees to confirm the presence of meniscal tears. The factors related to meniscal tears were analyzed by multiple logistic regression.

Results

A total of 54.5% of the farmers (48.7% of men and 60.1% of women) had meniscal tears. These tears were associated with gender, age, and BMI. We also identified an association between meniscal tears and CSWT, an especially important factor in farming [10,000–19,999 working hours, odds ratio = 2.16, 95% confidence interval (CI): 1.14-4.07, ≥20,000 working hours, odds ratio = 2.35, 1.45-3.80]. However, mechanical axis, knee injury history, and CLWT were not significantly related to meniscal tears.

Conclusion

This study's findings show that squatting for long periods, as an occupational factor, is related to meniscal tears.

Effects of work-related factors on self-reported smoking among female workers in call centers: a cross-sectional study

Objectives

This study conducted to investigate work-related factors in relation to smoking among women working in call centers in Gwangju, South Korea.

Methods

From 56 call centers (7320 employees), we selected 10 and conducted a survey using a structured questionnaire by randomly selecting 10% of workers from each center. A total of 387 subjects participated in this survey We analyzed for 375 respondents, after excluding men and those with missing responses. We analyzed the relationships of work-related factors such as emotional labor, workplace violence, employment type, annual salary, working hours, employment period with smoking, using multiple logistic regression analysis. Emotional labor and workplace violence were measured using the Korean Emotional Labor Scale (K-ELS) and Korean Workplace Violence Scale (K-WVS).

Results

The prevalence of current smoking among call center female workers was 13.6%. Univariate analysis showed that “Emotional disharmony and hurt”, “Experience of psychological and sexual violence from supervisors and co-workers” among items of K-ELS and K-WVS, working hours, annual salary correlated with smoking. After adjusting for emotional labor, workplace violence, employment type, annual salary, working hours, employment period, and age, only working hours show a significant association with smoking. Women who worked 40–49 h had 3.50 times (95% CI = 1.04–11.80) and worked more than 50 h had 8.68 times (95% CI = 1.89–39.78) greater odds of smoking as compared with women who worked less than 40 h.

Conclusions

Smoking was associated with working hours among female workers in call center. However, emotional labor and workplace violence did not show significant relationships with smoking.

Evaluation of the prevalence of musculoskeletal symptoms, presumptive diagnosis, medical care use, and sick leave among female school meal service workers

Background

Most of the school meal service workers in Korea are middle-aged individuals. They have high workload, which increases their incidence of musculoskeletal disorders. This study aimed to evaluate the prevalence and risk factors of subjective musculoskeletal symptoms, presumptive diagnosis, medical care use, and sick leave among female school meal workers.

Methods

We analyzed the results of musculoskeletal disease screening of 1581 female school meal workers. The screening consisted of self-administered questionnaire, history taking by occupational physicians, and physical examination. The prevalence of subjective musculoskeletal symptoms, presumptive diagnosis after initial examination by occupational physicians, use of medical care for more than 7 days, and sick leave due to musculoskeletal diseases during the past year were evaluated in this study. The relative risk of four outcome indicators of musculoskeletal disorders was compared with respect to potential factors, such as age, subjective physical loading, present illness, injury experience, and type of school, using log-binomial regression.

Results

The prevalence of subjective musculoskeletal symptom was 79.6%; presumptive diagnosis, 47.6%; hospital visits over 7 days, 36.4%; and sick leave, 7.3%. The relative risk of musculoskeletal symptoms by age (≥50 years vs < 50 years) was 1.04 (95% confidence interval (CI): 1.00–1.09); presumptive diagnosis of musculoskeletal disease, 1.17 (95% CI: 1.06–1.30); hospital visits over 7 days, 1.26 (95% CI: 0.85–1.85); and sick leave, 1.17 (95% CI: 1.02–1.34). The relative risk of musculoskeletal symptoms due to subjective physical loading (very hard vs low) was 1.45 (95% CI: 1.33–1.58); presumptive diagnosis, 2.92 (95% CI: 2.25); hospital visits over 7 days, 1.91 (95% CI: 1.02–3.59); and sick leave, 2.11 (95% CI: 1.63–2.74).

Conclusions

Subjective physical loading was a more important factor in musculoskeletal disorders than the age of female school meal workers.

Systemic sclerosis due to crystalline silica exposure among jewelry workers in Korea: two case reports

Background

Occupational exposure to crystalline silica is a potential risk factor for various systemic autoimmune diseases including systemic sclerosis. The etiology of systemic sclerosis is not conclusively known, but there are epidemiological studies that show the relationship between exposure to crystalline silica and risk of systemic sclerosis. Here we report, for the first time, two cases of crystalline silica-related systemic sclerosis in patients who worked in crystal processing in the jewelry-manufacturing field.

Case presentation

Case 1 is a 57-year-old man who had worked mainly in crystal processing for multiple jewelry-processing companies for 17 years, since the age of 15 years. He contracted tuberculosis at the age of 25 years and showed Raynaud’s phenomenon of both the hands and feet at age 32 years. Digital cyanosis and sclerosis developed at approximately age 41 years. The patient was diagnosed with systemic sclerosis at age 48 years.

Case 2 is a 52-year-old man who worked in crystal processing for various jewelry-processing companies for 7 years, since the age of 23 years. He first showed signs of cyanosis in the third and fourth digits of both hands at age 32 years, was diagnosed with Raynaud’s syndrome at age 37 years, and was diagnosed with systemic sclerosis at age 38 years.

Crystal processing is a detailed process that involves slabbing and trimming the selected amethyst and quartz crystals, which requires close proximity of the worker’s face with the target area. In the 1980s and 1990s, the working hours were 12 h per day, and the working environment involved 15 workers crowded into a small, 70-m² space with poor ventilation.

Conclusion

Two workers who processed crystals with a maximum crystalline silica content of 56.66% developed systemic sclerosis. Considering the epidemiological and experimental evidence, exposure to crystalline silica dust was an important risk factor for systemic sclerosis. An active intervention is necessary to reduce exposure in similar exposure groups in the field of jewelry processing.

Cases of acute mercury poisoning by mercury vapor exposure during the demolition of a fluorescent lamp factory

Background

In 2015, workers dismantling a fluorescent lamp factory in Korea were affected by mercury poisoning from exposure to mercury vapor.

Case presentation

Eighteen out of the 21 workers who participated in the demolition project presented with symptoms of poisoning and, of these, 10 had persistent symptoms even at 18 months after the initial exposure to mercury vapor. Early symptoms of 18 workers included a general skin rash, pruritus, myalgia, sleep disturbance, and cough and sputum production. Following alleviation of these initial symptoms, late symptoms, such as easy fatigue, insomnia, bad dreams, and anxiety disorder, began to manifest in 10 out of 18 patients. Seven workers underwent psychiatric care owing to sleep disturbance, anxiety disorder, and depression, and three workers underwent dermatologic treatment for hyperpigmentation, erythematous skin eruption, and chloracne-like skin lesions. Furthermore, three workers developed a coarse jerky movement, two had swan neck deformity of the fingers, and two received care at an anesthesiology clinic for paresthesia, such as burning sensation, cold sensation, and pain. Two workers underwent urologic treatment for dysfunction of the urologic system and impotence. However, symptomatic treatment did not result in satisfactory relief of these symptoms.

Conclusion

Awareness of the perils of mercury and prevention of mercury exposure are critical for preventing health hazards caused by mercury vapor. Chelation therapy should be performed promptly following mercury poisoning to minimize damage.

Air pollution and urinary n-acetyl-B-glucosaminidase levels in residents living near a cement plant

Background

To identify adverse renal effects due to air pollution derived from a cement plant in Korea. Urinary n-acetyl-B-glucosaminidase (U-NAG) levels in residents living near a cement plant were compared to those in a group who lived farther away from the plant.

Methods

From June to August 2013 and from August to November 2014, laboratory tests for U-NAG and heavy metal were conducted on 547 study participants. Based on the level of air pollution exposure, subjects were divided into the “less exposed group,” (LEG) which consisted of 66 persons who lived more than 5 km away from the cement plant, the “more exposed group from the rural area” (MEG-R), which consisted of 272 persons, and the “more exposed group from downtown area” (MEG-D), which consisted of 209 persons who lived within a 1 km radius of the cement plant. U-NAG levels >5.67 U/L were defined as “higher U-NAG” levels. We compared the prevalence of higher U-NAG levels and estimated the adjusted odds ratio (OR) by air pollution exposure using a chi-square test and multiple logistic regression analysis. Further, we estimated the interaction between air pollution exposure and heavy metal exposure in renal toxicity.

Results

The OR of higher U-NAG levels by MEG-D and MEG-R compared to LEG was 2.13 (95 % CI 0.86–4.96) and 4.79 (95 CI 1.65–10.01), respectively. Urinary cadmium (U-Cd), urinary mercury (U-Hg), age, occupation, hypertension, and diabetes had a significant association with higher U-NAG levels. However, blood lead (B-Pb), sex, and smoking were not associated with higher U-NAG. Especially, concurrent exposure to heavy metals (U-Hg or/and U-Cd) and air pollution had an additive adverse effect. In the group with both 4^th quartile heavy metal exposure (U-Cd or/and U-Hg) and air pollution exposure, the OR in MEG-R and MEG-D was 6.49 (95 % 1.42–29.65) and 8.12 (95 % CI 1.74–37.92), respectively, after adjustment for age, occupation, hypertension, diabetes.

Conclusions

U-NAG levels seem to be affected by air pollution exposure as well as age, hypertension, diabetes, and even low levels of cadmium and low levels of mercury. Moreover, concurrent exposure to heavy metals and air pollution can have additive cytotoxic renal effects.

Emphysema prevalence related air pollution caused by a cement plant

Background

To identify adverse pulmonary health effects due to air pollution derived from a cement plant in Korea. The emphysema prevalence in residents around a cement plant was compared to that in the group who live far away from the plant by chest films (PA and lateral view) and high-resolution computed tomography (HRCT) lung images.

Methods

From June to August in 2013 and from August to November in 2014, chest films and HRCT scan were conducted on residents over the age of 40 who lived around a cement plant. The residents were divided into two groups; a “more exposed group (MEG)” which consisted of 1,046 people who lived within a 1 km radius and a “less exposed group (LEG)” which consisted of 317 people who lived more than 5 km away from the same plant. We compared the emphysema prevalence and estimated the OR of this between the MEG and the LEG by using a chi-square and logistic regression on chest films and HRCT.

Results

The emphysema prevalence was 9.1 % in the LEG, 14.3 % in the MEG on chest films and 11.4 %, 17.8 % on the HRCT, respectively. The OR of the emphysema prevalence in MEG was 2.92 (95 % CI 1.77-4.83) on the chest films, 2.56 (95 % CI 1.64–3.99) on the HRCT after sex, age, body mass index (BMI), smoking history, residency period and firewood used history were adjusted. The OR in the less than 29 pack-years smoking history was 1.66 (95 % CI 0.92–3.06) and in the more than 30 pack-years was 3.05 (95 % CI 1.68–5.52) on the chest films, and was 1.68 (95 % CI 0.98–2.90), 2.93 (95 % CI 1.72–4.98) on the HRCT, respectively.

Conclusion

The emphysema prevalence seems to be affected by the level of exposure to air pollution derived from the cement plant as well as sex, age, BMI, and smoking history in this study. Moreover, the OR of the case of the more exposed to the air pollution was similar to that of the case in smoking.

Clinical results of treatment of garden type 1 and 2 femoral neck fractures in patients over 70-year old

INTRODUCTION

We retrospectively analyzed the clinical results of treatment of impacted or undisplaced femoral neck fractures (Garden types 1 and 2) by osteosynthesis in elderly patients >70-year old.

MATERIALS AND METHODS

We retrospectively reviewed the radiological results of 52 patients who were followed up for at least 6 months from April 2002 to December 2008. The average age of the patients was 77.6 years (range 70-97 years), and 38 patients were females. The mean follow-up period was 11.7 months (range 6-19 months). Thirteen cases were Garden type 1 fractures, and 39 were Garden type 2 fractures. We assessed the relationships between the occurrence of complications and age, sex, Garden stage, bone mineral density (BMD), history of contralateral hip fracture, and any additional hip injury.

RESULTS

Major complications occurred in 18 cases (34.6 %), including nonunion (8 cases), osteonecrosis (6 cases), stress fracture of the subtrochanter (2 cases), excessive pull-out of a screw (1 case), and deep infection (1 case). The development of complications was associated with Garden stage 2, BMD, and additional hip injury. However, other factors were not associated with complications. Reoperations were performed in 16 cases (30.1 %), and 2 of the patients died during follow-up.

CONCLUSION

A relatively high rate of complications or reoperations developed after treatment of Garden 2 femoral neck fractures in senile patients >70 years of age with osteoporosis. Although internal fixation has been recommended in the literature for undisplaced femoral neck fractures, primary arthroplasty may be a better option for treatment of Garden type 2 fractures in elderly patients.

In vivo time-sequential histological study focused on melanocytes: suggestion of golden time for intervention to prevent post-laser pigmentary changes

BACKGROUND

Post-inflammatory pigmentary changes after laser treatments are challenging adverse effect.

OBJECTIVE

To suggest an ideal time period with regard to intervention to prevent post-laser pigmentary changes, an in vivo time-sequential histological study focused on melanocytes was performed.

METHODS

The back skin of four volunteers was irradiated with Q-switched alexandrite laser (QSAL). In one subject (subject 4), topical corticosteroid was applied onto the irradiated skin from the time of irradiation to day 28. In all subjects, time-sequential skin biopsies were performed at baseline, an immediate time after irradiation, day 2, day 7, and day 28. Histological and immunohistochemical analyses were conducted.

RESULTS

Q-switched alexandrite laser led to the successful removal of pigments and most melanocytes from the epidermis in all subjects. At day 28, there was increased epidermal pigmentation in the skin of the subjects 1-3. It was noted that numerous activated melanocytes appeared on day 7, continued to be observed until day 28. However, in the subject 4, the melanocyte activation and post-laser pigmentary changes were not observed.

CONCLUSION

In regard to intervene melanocyte activation, at least 1 week after laser treatment is suggested as a 'golden' time period to prevent pigmentary changes.

Ventilation impairment of residents around a cement plant

Objectives

To identify adverse health effects due to air pollution derived from a cement plant in Korea. The ventilation impairment in residents around a cement plant was compared to another group through a pulmonary function test (PFT).

Methods

From June to August of 2013, both a pre and post-bronchodilator PFT was conducted on a “more exposed group (MEG)” which consisted of 318 people who lived within a 1 km radius of a cement plant and a “less exposed group (LEG)” which consisted of 129 people who lived more than 5 km away from the same plant. The largest forced expiratory volume in a one second (FEV1) reading and a functional residual capacity (FVC) reading were recorded after examining the data from all of the usable curves that were agreed upon as valid by PFT experts of committee of National Institute of Environmental Research. The global initiative for chronic obstructive lung disease (GOLD) criteria for COPD, defined the FEV1/FVC ratio < 0.7 as the obstructive type, and the FEV1/FVC ratio ≧ 0.7 and FVC% predicted < 80% were as the restrictive type. The FVC% predicted value was estimated using Korean equation. We compared the proportion of lung function impairments between the MEG and the LEG by using a chi-square, and estimated the OR of obstructive and restrictive ventilation impairments by logistic regression.

Results

The obstructive type impairment proportion was 9.7% in the MEG, whereas it was 8.5% in the LEG. The restrictive type was 21.6% in the MEG which was more than the 12.4% of the LEG. The odds ratio (OR) of total ventilation impairment in the MEG was 2.63 (95% CI 1.50 ~ 4.61) compared to the LEG. The OR of obstructive type in the MEG was 1.60 (95% CI 0.70 ~ 3.65), the smoking history was 3.10 (CI 1.10 ~ 8.66) whereas OR of restrictive type in the MEG was 2.55 (95% CI 1.37 ~ 4.76), the smoking history was 0.75 (95% CI 0.35 ~ 1.60) after adjusting for sex and age. Level of exposure to particulate played a role in both types. However, it appeared to be a significant variable in restrictive type, while smoking history was also an important variable in obstructive type.

Conclusion

Although this study is a limited cross-section study with a small number of subjects, ventilation impairment rate is higher in the MEG. There might be a possibility that it is due to long-term exposure to particulate dust generated by the cement plant.

Cytochalasin B inhibits the proliferation of human glioma U251 cells through cell cycle arrest and apoptosis

Cytochalasin B (CB) is known to inhibit a number of cancer types, but its effects on gliomas are unknown. We examined the in vitro effects of CB on the proliferation of human glioma U251 cells, as well as determined its mechanism of action. Cell proliferation was determined using CCK-8. The effect of CB on U251 cell morphology was observed under a transmission electron microscope. Cell cycle distribution was assessed using propidium iodine and Giemsa staining, and cell apoptosis was determined by annexin V-fluorescein isothiocyanate/propidium iodide. Cell cycle-related proteins were determined by Western blot. CB effectively inhibited U251 cell proliferation in a dose- and time-dependent manner. The 24, 48, 72, and 96 h IC50 values were 6.41 x 10(-2), 9.76 x 10(-4), 2.57 x 10(-5), and 2.08 x 10(-5) M, respectively. CB increased the proportion of cells in the G2/M phase in a dose-dependent manner, thus increasing the mitotic index and decreasing cdc2 and cyclin B1 protein levels. CB induced morphological changes in the cytoskeleton. Additionally, 10(-5) M CB induced apoptosis in 23.4 ± 0.5% of U251 cells (P < 0.05 vs control group). Caspase-3, -8, and -9 activities were increased after CB treatment. CB inhibited U251 glioma cell proliferation by damaging the microfilament structure. CB also induced glioma cell apoptosis, suggesting that it may be an effective therapeutic agent against gliomas.

Cardiovascular disease risk of bus drivers in a city of Korea

Objective

To prevent the occurrence of CV events such as MI and stroke among professional drivers in Korea, bus drivers were compared to other occupations through the Framingham risk scoring system (FRS) or metabolic syndrome (MS) of cardiovascular disease (CVD) risk assessment methods.

Methods

In October 2012, a health examination survey was conducted for 443 male bus drivers in a big city. Their CVD risk factors were compared to those of a ‘total employed’ (A group) and ‘crafts and machine operators’ (B group) extracted from Fifth Korea National Health and Nutrition Examination Survey (KNHANES, 2010) data by using FRS and MS. We calculated proportions of the CVD risk factors distribution between bus drivers and the A, B groups by the bootstrapping method. The Odds ratio (OR) between CV event risk combining MS with CHD equivalent risk of FRS and occupational factors like shift patterns and professional driving duration/age ratios (PDAR) of bus drivers was calculated through multinominal logistic regression.

Results

The proportion of BMI ≥ 25 kg/m² was 53.9% and waist circumference ≥ 90cm was 40.9% among bus drivers. Hypertension and MS prevalence of bus drivers was 53.3%, 49.9% which is higher than 17.6%, 22.6% in the A group and 19.7%, 23.8% in the B group respectively. OR of high CV event risk in alternate shift was 2.58 (95% CI 1.33~5.00) in comparison with double shift pattern and OR in PDAR ≥ 0.5 was 2.18 (95% CI 1.15~4.14).

Conclusion

Middle aged male drivers in a big city of Korea stand a higher chance of developing CV event than other professions of the same age.

Impact of MTHFR polymorphisms on methylation of MGMT in glioma patients from Northeast China with different folate levels

Hypomethylation of the O6-methylguanine-DNA-methyltransferase (MGMT) promoter in glioma cells has been associated with temozolomide resistance. S-adenosylmethionine (SAM), which is produced during folate metabolism, is the main source of methyl groups during DNA methylation. As a key enzyme during folate metabolism, polymorphisms of 5,10-methylenetetrahydrofolate reductase (MTHFR) may regulate folate end-products. We investigated the effect of typical polymorphisms of MTHFR (C677T and A1298C) on MGMT methylation based on different serum folate levels in patients with glioma from Northeast China. A total of 275 patients with glioma and 329 without malignant tumors were tested. Serum folate concentration was assayed by using the electrochemiluminescence immunoassay. MTHFR polymorphisms were detected by Taqman-Fluorescence quantitative polymerase chain reaction (PCR). Methylation-specific PCR was used to assess MGMT methylation. The constituent ratio of glioma patients below the serum folate biological reference value was significantly higher than that of the control population (P < 0.001). In patients with oligodendroglioma and glioblastoma, heterozygotes for the A1298C mutation were found in higher frequency than homozygotes or wild types (oligodendroglioma, P < 0.001; glioblastoma, P < 0.01). When grouped by the median or biological reference value of serum folate, only homozygotes for C677T with low levels of folate were significantly associated with decreased methylation of MGMT (median, P < 0.001; biological reference value, P = 0.036). These data suggest that, in combination with a negative folate balance in glioma patients, T/T genotypes in MTHFR C677T may be associated with MGMT demethylation.

High-performance top-gated monolayer SnS2 field-effect transistors and their integrated logic circuits

Two-dimensional (2D) layered semiconductors are very promising for post-silicon ultrathin channels and flexible electronics due to the remarkable dimensional and mechanical properties. Besides molybdenum disulfide (MoS2), the first recognized 2D semiconductor, it is also important to explore the wide spectrum of layered metal chalcogenides (LMCs) and to identify possible compounds with high performance. Here we report the fabrication of high-performance top-gated field-effect transistors (FETs) and related logic gates from monolayer tin disulfide (SnS2), a non-transition metal dichalcogenide. The measured carrier mobility of our monolayer devices reaches 50 cm(2) V(-1) s(-1), much higher than that of the back-gated counterparts (~1 cm(2) V(-1) s(-1)). Based on a direct-coupled FET logic technique, advanced Boolean logic gates and operations are also implemented, with a voltage gain of 3.5 and output swing of >90% for the NOT and NOR gates, respectively. The superior electrical and integration properties make monolayer SnS2 a strong candidate for next-generation atomic electronics.

Factors influencing medical student attrition and their implications in a large multi-center randomized education trial

Participant attrition may be a significant threat to the generalizability of the results of educational research studies if participants who do not persist in a study differ from those who do in ways that can affect the experimental outcomes. A multi-center trial of the efficacy of different computer-based instructional strategies gave us the opportunity to observe institutional and student factors linked to attrition from a study and the ways in which they altered the participation profile. The data is from a randomized controlled trial conducted at seven US medical schools investigating the educational impact of different instructional designs for computer-based learning modules for surgical clerks. All students undertaking their surgical clerkships at the participating schools were invited participate and those that consented were asked to complete five study measures during their surgery clerkship. Variations in study attrition rates were explored by institution and by participants' self-regulation, self-efficacy, perception of task value, and mastery goal orientation measured on entry to the study. Of the 1,363 invited participants 995 (73 %) consented to participate and provided baseline data. There was a significant drop in the rate of participation at each of the five study milestones with 902 (94 %) completing at least one of two module post-test, 799 (61 %) both module post-tests, 539 (36 %) the mid-rotation evaluation and 252 (25 %) the final evaluation. Attrition varied between institutions on survival analysis (p < 0.001). Small but statistically significant differences in self-regulation (p = 0.01), self-efficacy (p = 0.02) and task value (p = 0.04) were observed but not in mastery or performance goal orientation measures (p = NS). Study attrition was correlated with lower achievement on the National Board of Medical Examiners subject exam. The results of education trials should be interpreted with the understanding that students who persist may be somewhat more self-regulated, self-efficacious and higher achievers than their peers who drop out and as such do not represent the class as a whole.

Just enough, but not too much interactivity leads to better clinical skills performance after a computer assisted learning module

BACKGROUND

Well-designed computer-assisted instruction (CAI) can potentially transform medical education. Yet little is known about whether specific design features such as direct manipulation of the content yield meaningful gains in clinical learning. We designed three versions of a multimedia module on the abdominal exam incorporating different types of interactivity.

METHODS

As part of their physical diagnosis course, 162 second-year medical students were randomly assigned (1:1:1) to Watch, Click or Drag versions of the abdominal exam module. First, students' prior knowledge, spatial ability, and prior experience with abdominal exams were assessed. After using the module, students took a posttest; demonstrated the abdominal exam on a standardized patient; and wrote structured notes of their findings.

RESULTS

Data from 143 students were analyzed. Baseline measures showed no differences among groups regarding prior knowledge, experience, or spatial ability. Overall there was no difference in knowledge across groups. However, physical exam scores were significantly higher for students in the Click group.

CONCLUSIONS

A mid-range level of behavioral interactivity was associated with small to moderate improvements in performance of clinical skills. These improvements were likely mediated by enhanced engagement with the material, within the bounds of learners' cognitive capacity. These findings have implications for the design of CAI materials to teach procedural skills.

Field electron emission of ZnO nanowire pyramidal bundle arrays

A facile hydrothermal method was adopted to in situ grow ZnO nanowire pyramidal bundle arrays on zinc substrates at low growth temperature without the assistance of catalysts and templates. The bundle arrays were shown to form by sticking of nanowires at their tips. Field electron emission characterization of nanowires bundle arrays revealed a very low turn-on electric field of about 2.3 V/microm and a threshold electric field (corresponding to the field electron emission current density of 10 mA/cm2) of 6.8 V/microm, which are comparable to those observed in carbon nanotube arrays. The bundle arrays also show pronounced long-term field electron emission stability at a high current density. In addition, the formation mechanism of the pyramidal bundled arrays and the origin of the peculiar field electron emission properties were discussed.

High-quality Graphenes via a facile quenching method for field-effect transistors

Single- and few-layer graphene sheets with sizes up to 0.1 mm were fabricated by simply quenching hot graphite in an ammonium hydrogen carbonate aqueous solution. The identity and thickness of graphene sheets were characterized with transmission electron microscopy, atomic force microscopy, and Raman spectroscopy. In addition to its simplicity and scalability, the present synthesis can produce graphene sheets with excellent qualities in terms of sizes, purity, and crystal quality. The as-produced graphene sheets can be easily transferred to solid substrates for further processing. Field-effect transistors based on individual graphenes were fabricated and shown to have high ambipolar carrier mobilities.

Phase II study and biomarker analysis of cetuximab combined with modified FOLFOX6 in advanced gastric cancer

This prospective study was conducted with the Korean Cancer Study Group to evaluate the efficacy and safety of cetuximab combined with modified FOLFOX6 (mFOLFOX6) as first-line treatment in recurrent or metastatic gastric cancer and to identify potential predictive biomarkers. Patients received cetuximab 400 mg m⁻² at week 1 and 250 mg m⁻² weekly thereafter until disease progression. Oxaliplatin (100 mg m⁻²) and leucovorin (100 mg m⁻²) were administered as a 2-h infusion followed by a 46-h continuous infusion of 5-fluorouracil (2400 mg m⁻²) every 2 weeks for a maximum of 12 cycles. Biomarkers potentially associated with efficacy were analysed. Among 38 evaluable patients, confirmed response rate (RR) was 50.0% (95% CI 34.1–65.9). Median time-to-progression (TTP) was 5.5 months (95% CI 4.5–6.5) and overall survival (OS) 9.9 months. Eleven patients having tumour EGFR expression by immunohistochemistry with low serum EGF and TGF-α levels showed a 100% RR compared to 37.0% in the remaining 27 patients (P<0.001). Moreover, ligand level increased when disease progressed in seven out of eight patients with EGFR expression and low baseline ligand level. No patient exhibited EGFR amplification or K-ras mutations. Gastric cancer patients with EGFR expression and low ligand levels had better outcomes with cetuximab/mFOLFOX6 treatment.

Vertically aligned p-type single-crystalline GaN nanorod arrays on n-type Si for heterojunction photovoltaic cells

Vertically aligned Mg-doped GaN nanorods have been epitaxially grown on n-type Si substrate to form a heterostructure for fabricating p-n heterojunction photovoltaic cells. The p-type GaN nanorod/n-Si heterojunction cell shows a well-defined rectifying behavior with a rectification ratio larger than 10(4) in dark. The cell has a high short-circuit photocurrent density of 7.6 mAlcm2 and energy conversion efficiency of 2.73% under AM 1.5G illumination at 100 mW/cm2. Moreover, the nanorod array may be used as an antireflection coating for solar cell applications to effectively reduce light loss due to reflection. This study provides an experimental demonstration for integrating one-dimensional nanostructure arrays with the substrate to directly fabricate heterojunction photovoltaic cells.

High-Aspect-Ratio Aluminum Borate Nanowire Bundles Supported by Sucrose

High-aspect-ratio and single-crystal aluminum borate (Al(18)B(4)O(33)) nanowire bundles with an ordered orientation were synthesized by using an innovative sucrose-assisted growth process. The process involves the dehydration and polycondensation of aluminum borate-sucrose solution to form a highly viscous precursor. The sucrose plays a crucial role in the growth of the nanowire bundles by supporting as a polymeric substrate and a type of adhesive template. Electron microscopy was used to characterize the high-aspect-ratio nanowire bundles. A possible growth mechanism for the nanowire bundles is proposed.

Improved therapeutic outcomes of DLBCL after introduction of rituximab in Korean patients

The addition of rituximab to cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) has been shown to improve the outcome in all age groups with newly diagnosed diffuse large B-cell lymphoma (DLBCL). We conducted a retrospective analysis to evaluate the impact of this combination therapy on DLBCL outcomes in Korea. From October 2001 to June 2004, newly diagnosed DLBCL patients in nine Korean institutes were included. All of these 81 patients were treated with three or more cycles of rituximab plus CHOP (R-CHOP) combination chemotherapy (R group), and followed for a minimum of 12 months. For comparison, a historical cohort of patients was used and analyzed for "Clinicopathologic characteristics of Korean non-Hodgkin's lymphomas (NHLs) based on Revised American Lymphoma (REAL) classification" in 1999. Among the 1,098 NHL patients, the data of 214 DLBCL patients, who were treated with CHOP chemotherapy in first-line, were analyzed (C group). We compared outcomes between the C group and the R group. A total of 295 patients were evaluated (C group, 214; R group, 81). The complete response (CR) rate was higher in R group (73 vs 91%, p=0.001). The 2-year event-free survival (EFS) rate was significantly higher in R group (78 vs 85%, p=0.0194). This survival benefit was maintained in high-risk patients according to the international prognostic index (IPI) (p=0.0039), regardless of age. However, there was no significant difference in low-risk patients. The addition of rituximab to CHOP combination chemotherapy for DLBCLs showed improved outcomes, particularly in high-risk group according to the IPI. Long-term follow-up results will be needed to confirm these results.

Development of AFLP-derived STS markers for the selection of 5-methyltryptophan-resistant rice mutants

To increase the specific free amino acid content in the japonica rice (Oryza sativa L.) cultivar Donganbyeo, mutant cell lines resistant to growth inhibition by 5-methyltryptophan (5MT) were selected from embryo-cultured callus irradiated with 50 Gy gamma-rays. Four 5MT-resistant homozygous M4 lines, MRI-40, MRI-116, MRII-8, and MRII-12, were obtained. The mean content of nine free essential amino acids were 70.1, 72.5, 31.7, and 35.4% greater than the original variety in these four mutant lines, respectively. For AFLP analysis, 8 EcoRI (+2) and 8 MseI (+3) primers used in 45 primer combinations generated a total of 3,684 bands with a mean of 82 bands, of which 361 (9.8%) were clearly polymorphic with the control cultivar, the four 5MT-resistant mutants, and five sensitive lines. The lines were grouped into three clusters through cluster analysis using unweighted pair grouping method of averages. The 36 polymorphic PCR products present only in the four homozygous 5MT-resistant lines were cloned and sequenced, and 10 of these sequenced products were converted into sequence tagged site (STS) markers. These STS primer sets were designated OSMR1-OSMR10. Six STS primer sets (OSMR1, OSMR2, OSMR3, OSMR4, OSMR5, and OSMR6) generated a single monomorphic PCR product identical in size to the original AFLP fragments. The broad applicability of these STS markers for the screening of 5MT resistance was evaluated with seven putative 5MT-resistant M2 plants (PM-1 to PM-7). Four STS markers (OSMR1, OSMR2, OSMR4, and OSMR5) out of six STS primer sets were revealed as polymorphic products between the control cultivar and the seven M2 plants. These markers can be utilized for the fine selection of 5MT resistance in rice, and this PCR-screening technique is less time-consuming, less labor-intensive, and more accurate and reliable than selection based solely on phenotypic evaluation involving soaking in 5MT solutions.

Massive thrombosis after central venous catheterization in a patient with previously undiagnosed Behcet's disease

Thrombosis is an important complication of central venous catheterization. Among the many intrinsic and extrinsic factors, the patient's medical disease can play a role in thrombogenesis. Behcet's disease (BD), classified as a vasculitis, is a multisystem disease involving the small blood vessels. It is often difficult to recognize and diagnose the disease. A 24-yr-old female patient showed massive central venous thrombosis which caused superior vena cava syndrome after subclavian vein catheterization. Twenty days after catheterization, the patient exhibited swelling of the face, neck, and both upper extremities. Despite thrombectomy and continuous anticoagulation therapy, her facial and upper extremity swelling reappeared and follow-up chest computed tomography (CT) showed the recurrent thrombosis in the same central veins previously affected. A diagnosis of BD was then made. Following steroid therapy, neither clinical symptoms nor CT findings suggestive of central venous thrombosis were observed during the subsequent 6-months of follow-up period. This case emphasizes that central venous catheterization in a patient with BD should be performed with great caution.

Magnesium sulfate does not reduce postoperative analgesic requirements

BACKGROUND

Because magnesium blocks the N-methyl-D-aspartate receptor and its associated ion channels, it can prevent central sensitization caused by peripheral nociceptive stimulation. However, transport of magnesium from blood to cerebrospinal fluid (CSF) across the blood-brain barrier is limited in normal humans. The current study was designed to evaluate whether perioperative intravenous magnesium sulfate infusion affects postoperative pain.

METHODS

Sixty patients undergoing abdominal hysterectomy received 50 mg/kg intravenous magnesium sulfate as a bolus dose followed by a continuous infusion of 15 mg x kg(-1) x h(-1) for 6 h (magnesium group) or the same volume of isotonic saline (control group). At the end of surgery, serum and CSF magnesium concentration were measured in both groups. The cumulative postoperative analgesic consumption was measured to assess the analgesic effect using a patient-controlled epidural analgesia device. Pain intensities at rest and during forced expiration were evaluated at 6, 24, 48, and 72 h postoperatively.

RESULTS

At the end of surgery, patients in the magnesium group had significantly greater postoperative serum magnesium concentrations compared with both preoperative and control group values (P < 0.001). Despite significantly higher serum magnesium concentrations in the magnesium group, there was no significant difference in magnesium concentration measured in postoperative CSF. Cumulative postoperative analgesic doses were similar in both groups. However, there was observed an inverse relation between cumulative postoperative analgesic consumption and the CSF magnesium concentration in both groups. Visual analog pain scores at rest and during forced expiration were similar and less than 4 in both groups.

CONCLUSIONS

Perioperative intravenous administration of magnesium sulfate did not increase CSF magnesium concentration and had no effects on postoperative pain. However, an inverse relation between cumulative postoperative analgesic consumption and the CSF magnesium concentration was observed. These results suggest that perioperative intravenous magnesium infusion may not be useful for preventing postoperative pain.

Nitric oxide prevents the IFN-gamma/LPS-induced hepatotoxicity in a protein kinase G-independent manner

Although it has been well known that the role of LPS on hepatotoxicity is mediated through TNF-alpha, the direct cytotoxic effect of LPS on IFN-gamma-primed hepatocytes has not yet been clearly demonstrated. Here, we demonstrate that the IFN-gamma-mediated death of murine embryonic liver BNL CL2 cells is potentiated by LPS (0.5 microg/ml). In addition, an exogenous NO donor, sodium nitroprusside (SNP) significantly prevents cell death induced by IFN-gamma alone or IFN-gamma plus LPS (IFN-gamma/LPS) in a dose-dependent manner over 25 microM. SNP significantly blocked the death of BNL CL2 cells only when it was added within 12 hr after treatment of IFN-gamma and IFN-gamma/LPS. The preventive effect of SNP occurred in parallel with the suppression of caspase 3-like protease activation. We have also demonstrated that a relatively high concentration as well as an appropriate period of exposure to NO may be critical to maintain cell viability from the cytotoxic effect of IFN-gamma and IFN-gamma/LPS. Furthermore, the preventive effect of SNP on IFN-gamma/LPS-induced cell death is mediated by a protein kinase G (PKG)-independent manner.

Transcription factor decoy for activator protein-1 (AP-1) inhibits high glucose- and angiotensin II-induced type 1 plasminogen activator inhibitor (PAI-1) gene expression in cultured human vascular smooth muscle cells

AIMS/HYPOTHESIS

Multiple factors, including hyperglycaemia and angiotensin II (Ang II), stimulate plasminogen activator inhibitor-1 (PAI-1) gene expression in human vascular smooth muscle cells. This study tested the hypothesis that hyperglycaemia and Ang II stimulate PAI-1 gene expression through activator protein-1 (AP-1) binding sites.

METHODS

We evaluated the role of AP-1 in PAI-1 gene expression in human vascular smooth muscle cells under high D-glucose and Ang II stimulation using a double-stranded cis-element AP-1 oligodeoxynucleotide (decoy ODN).

RESULTS

Activator protein 1 activity was stimulated by high glucose and Ang II treatment and the AP-1 decoy ODN, but not a mismatched decoy ODN, competed for AP-1 activity. The increase in PAI-1 expression by high glucose and Ang II was significantly attenuated by the AP-1 decoy ODN (p <0.05 or p < 0.01). The increase in PAI-1 expression by high glucose and Ang II action on AP-1 sites was also confirmed by promoter analysis of PAI-1. Activator protein 1 activation in response to either high glucose or co-stimulation with high glucose and Ang II was inhibited completely by calphostin C (a PKC inhibitor) and partially by genistein (a protein tyrosine kinase inhibitor).

CONCLUSION/INTERPRETATION

This study shows that high glucose and Ang II stimulate PAI-1 expression through AP-1 binding sites. Signal transduction after AP-1 activation by both high glucose and Ang II largely depends on PKC activation. These data indicate an important role for AP-1 in PAI-1 expression.

Spontaneous subconjunctival orbital fat prolapse: report of three cases

Spontaneous subconjunctival orbital fat prolapse is an uncommon but benign entity. It is seldom discussed in the literature, and is sometimes confused with other ocular surface tumors, such as dermolipoma. We present 3 cases, two of which are bilateral, the other being unilateral. Two cases underwent surgical excision due to ocular irritation, and the pathology proved mature adipose tissue compatible with the diagnosis. Computed tomography (CT) was available for 1 case and revealed a fat-compatible radiolucent mass continuous with the intraconal fat. Some other reports have presumed that the intraconal fat was prolapsed from a dehiscence of Tenon's capsule. However, according to our surgical findings, we suggest that the possible weak point for intraconal orbital fat prolapse is between the regions where the rectus muscle tendons penetrate into Tenon's capsule. The fat just bulges anteriorly, but not penetrates the Tenon's capsule and the intermuscular septum.

Determination of hypoxic region by hypoxia marker in developing mouse embryos in vivo: a possible signal for vessel development

Hypoxia is a well-known signal for angiogenesis, but the recent proposal that hypoxia exists in developing embryonic tissues and that it induces vascular development remains to be proven. In the present study, we demonstrate the presence of hypoxia in normal developing embryos by means of a hypoxia marker, pimonidazole, and its associated antibody. Our data clearly show that hypoxia marker immunoreactivity was highly detected in developing neural tubes, heart, and intersomitic mesenchyme at an early stage of organogenesis, suggesting that hypoxia may exist in the early stages of embryo development. We also found that hypoxia inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) were spatiotemporally co-localized with possible hypoxic regions in embryos. Investigation of platelet endothelial cell adhesion molecule (PECAM) expression provides evidence that endothelial cells proliferate and form the vessels in the hypoxic region in developing organs. Furthermore, we found that hypoxia induced both HIF-1alpha and VEGF in F9 embryonic stem and differentiated cells. Thus, we suggest that hypoxia may exist widely in developing embryonic tissues and that it may act as a signal for embryonic blood vessel formation in vivo.

Cloning and characterization of tissue inhibitor of metalloproteinase-3 (TIMP-3) from shark, Scyliorhinus torazame

We cloned the full-length cDNA encoding TIMP-3 from the cartilage of cloudy dogfish, Scyliorhinus torazame. The entire open reading frame was composed of 645 nucleotides and 214 residues including 12 conserved cysteines and asparagine-184, a putative site for N-linked sugars. It showed about 72% identity to those of other species based on the deduced amino acid sequence. The mRNA of shark TIMP-3 were expressed abundantly in brain and cartilage tissues. To investigate the roles of shark TIMP-3, an expression vector was constructed and transfected into HT1080 human fibrosarcoma cells. Overexpression of shark TIMP-3 reduced the activity of MMP-2 in gelatin zymography. Through human Alu PCR based CAM assay, we also confirmed that shark TIMP-3 transfected HT1080 cells had less intravasation effects.

A prospective randomized study of Chop versus Chop plus alpha-2B interferon in patients with intermediate and high grade non-Hodgkin's lymphoma: the International Oncology Study Group NHL1 Study

The addition of a brief alpha interferon regimen to each CHOP induction cycle, plus one year of alpha interferon thrice weekly maintenance therapy, has no early effect on response rates or survival in patients with Intermediate or High grade cell NHL.

BACKGROUND

The CHOP (Cyclophosphamide, Adriamycin. Vincristine, Prednisone) regimen is the most widely used first-line therapy for patients with Intermediate or High Grade (IG/HG) non-Hodgkin's lymphoma (NHL). Alpha 2b interferon (INF) enhances response rates and improves survival in low-grade NHL. The International Oncology Study Group (IOSG) conducted a prospective randomized study comparing CHOP alone or combined with INF in patients with IG/HG-NHL. The primary study aim was to compare the objective response rates in these patient cohorts.

PATIENTS AND METHODS

Patients with a confirmed diagnosis of measurable NHL of International Working Formulation (IWF) groups D to H histology were randomized to receive CHOP alone or CHOP with 5Mu INF s.c. for 5 days on days 22 to 26 of each 28 day cycle with INF 5 million units (Mu) given three times per week subcutaneously for 52 weeks in those patients who responded to CHOP plus INF.

RESULTS

The overall response rates were equivalent in both groups: CHOP alone (214 patients) 81% (complete 55%, partial 26%); CHOP plus INF (221 patients) 80% (complete 54%, partial 26%). At 36 months, the actuarial survival rate was equivalent in both groups.

CONCLUSIONS

There is no apparent early advantage in terms of response or survival conferred by adding the study INF regimen to CHOP therapy for patients with IG/HG-NHL.

Radical-scavenging activities of citrus essential oils and their components: detection using 1,1-diphenyl-2-picrylhydrazyl

Thirty-four kinds of citrus essential oils and their components were investigated for radical-scavenging activities by the HPLC method using 1,1-diphenyl-2-picrylhydrazyl (DPPH). To examine the oils' relative radical-scavenging activities compared with that of a standard antioxidant, Trolox was employed. All of the essential oils were found to have scavenging effects on DPPH in the range of 17. 7-64.0%. The radical-scavenging activities of 31 kinds of citrus essential oils were comparable with or stronger than that of Trolox (p < 0.05). The oils of Ichang lemon (64.0%, 172.2 mg of Trolox equiv/mL), Tahiti lime (63.2%, 170.2 mg of Trolox equiv/mL), and Eureka lemon (61.8%, 166.2 mg of Trolox equiv/mL) were stronger radical scavengers than other citrus oils. Citrus volatile components such as geraniol (87.7%, 235.9 mg of Trolox equiv/mL), terpinolene (87.4%, 235.2 mg of Trolox equiv/mL), and gamma-terpinene (84.7%, 227.9 mg of Trolox equiv/mL) showed marked scavenging activities on DPPH (p < 0.05).

Increasing tryptophan synthesis in a forage legume Astragalus sinicus by expressing the tobacco feedback-insensitive anthranilate synthase (ASA2) gene

A cDNA clone that encodes a feedback-insensitive anthranilate synthase (AS), ASA2, isolated from a 5-methyl-tryptophan (Trp) (5MT)-resistant tobacco cell line under the control of the constitutive cauliflower mosaic virus 35S promoter, was introduced into the forage legume Astragalus sinicus by Agrobacterium rhizogenes with kanamycin selection. The 35S-ASA2 gene was expressed constitutively as demonstrated by northern-blot hybridization analyses and the presence of feedback-insensitive AS. Hairy root lines transformed with 35S-ASA2 grew in concentrations of up to 100 microM 5MT, whereas the controls were completely inhibited by 15 microM 5MT. Expression of the feedback-insensitive ASA2 resulted in a 1.3- to 5.5-fold increase in free Trp. Kinetic studies of the AS activity demonstrate the Trp feedback alterations and indicate that the ASA2 alpha-subunit can interact with the native A. sinicus beta-subunit to form an active enzyme. The ASA2 transcript and high free Trp were also detected in the leaves, stems, and roots of plants regenerated from the transformed hairy roots. Thus, we show for the first time that ASA2 can be used to transform plants of a different species to increase the levels of the essential amino acid Trp and impart 5MT resistance.

Endogenous Klebsiella pneumoniae endophthalmitis associated with prostate abscess: case report

A young alcoholic and heavy smoker was admitted because of Klebsiella pneumoniae bacteremia. The abdominal and pelvic computed tomography with enhancement revealed an abscess in the right prostate. He experienced blurred vision of his left eye on the third day during admission. Initial ocular examination revealed mild reaction in the anterior chamber and vitreous as well as multiple Roth's spots in the retina. The administration of empirical antibiotics including cefazolin and gentamicin intravenously was changed to ceftriaxone and amikacin after ophthalmologic consultation. After parenteral antibiotics for 3 weeks, the systemic condition was controlled, and the vision remained stable. During the past decades, many cases of endogenous Klebsiella pneumoniae endophthalmitis associated with liver abscess were reported in Taiwan. However, documented reports of this condition associated with a prostate abscess are rare. This case, classified as posterior focal endogenous endophthalmitis, had good prognosis under appropriate antibiotic treatment. Early diagnosis and prompt therapy are important for control of sepsis and restoration of vision.

The recent development of emergency medicine in South Korea

Emergency medicine has developed rapidly in South Korea in the past decade, giving Korea one of the most advanced systems of emergency medical care in Asia. This article reviews the overall health care system and medical climate in Korea, as well as the great progress made in establishing emergency medicine as a specialty. It also describes the many improvements implemented in academic emergency medicine, emergency patient care, and emergency medicine management systems. Although the current economic crisis offers new challenges, much optimism remains about the future of this new Korean specialty.

Tissue culture-specific expression of a naturally occurring tobacco feedback-insensitive anthranilate synthase

A cDNA and corresponding promoter region for a naturally occurring, feedback-insensitive anthranilate synthase (AS) alpha-subunit gene, ASA2, has been isolated from an unselected, but 5-methyl-tryptophan-resistant (5MTr), tobacco (Nicotiana tabacum) cell line (AB15-12-1). The ASA2 cDNA contains a putative transit peptide sequence, and Southern hybridization shows that more than one closely related sequence is present in the tobacco genome. The ASA2 cDNA complemented a trpE nonsense mutant Escherichia coli strain, allowing growth on 300 microm 5MT-containing minimal medium without tryptophan, and cell extracts contained feedback-insensitive AS activity. The 5MTr was lost when the E. coli strain was transformed with an ASA2 site-directed mutant (phenylalanine-107-arginine-108 --> serine-107-glutamine-108). Identical nucleotide sequences encoding the phenylalanine-107-arginine-108 region have been found in polymerase chain reaction-amplified 326-bp ASA2 genomic fragments of wild-type (5-methyl-tryptophan-sensitive [5MTs]) tobacco and a progenitor species. High-level ASA2 transcriptional expression was detected only in 5MTr-cultured cells, not in 5MTs cells or in plants. Promoter studies indicate that tissue specificity of ASA2 is controlled by the promoter region between -2252 and -607. Since the ASA2 promoter sequences are not substantially different in the 5MTr and 5MTs lines, the increased levels of ASA2 mRNA in the 5MTr lines are most likely due to changes in a regulatory gene affecting ASA2 expression.

Epidural verapamil reduces analgesic consumption after lower abdominal surgery

In this double-blind study, we administered lumbar epidural bupivacaine or bupivacaine plus verapamil to investigate the possible role of the calcium channel blocker, verapamil, in postoperative pain. One hundred patients (ASA physical class I or II) scheduled for lower abdominal surgery were randomly assigned to one of four groups. Group 1 received 10 mL of 0.5% epidural bupivacaine injected 15 min before incision, followed by 10 mL of epidural normal saline 30 min after incision. Group 2 received 10 mL of epidural normal saline injected before incision, followed by 10 mL of 0.5% epidural bupivacaine 30 min after incision. Group 3 received 10 mL of 0.5% epidural bupivacaine plus 5 mg of verapamil injected before incision, followed by 10 mL of epidural normal saline 30 min after incision. Group 4 received the same drugs as Group 3, in the reverse order. Pain and mood numeric rating scores, sedation scores, Prince Henry scores, patient-controlled cumulative postoperative analgesic consumption, and the incidence of side effects were assessed 2, 6, 12, 24, and 48 h after the operation in each group. Cumulative postoperative analgesic consumption in Groups 3 and 4 was significantly lower (P < 0.05) than that in Groups 1 and 2 24 and 48 h after surgery. There were no differences in the pain, mood, and sedation scores and the incidence of side effects among the four groups. We conclude that epidural verapamil decreases postoperative pain, possibly by interfering with normal sensory processing and by preventing the establishment of central sensitization.

IMPLICATIONS

Calcium plays an important role in pain physiology at the spinal cord level. We examined the effect of bupivacaine plus verapamil (calcium channel blocker) and of bupivacaine alone. We demonstrated that the combination, administered epidurally, resulted in less postoperative analgesic consumption than bupivacaine alone.

Small-dose fentanyl: optimal time of injection for blunting the circulatory responses to tracheal intubation

This study was designed to examine the optimal time of injection of a small dose of fentanyl during anesthetic induction to attenuate circulatory responses to laryngoscopy and tracheal intubation. One hundred seventy patients were randomly assigned to one of five groups. In Groups II, III, IV, and V, patients received fentanyl (2 microg/kg) 1, 3, 5, or 10 min before tracheal intubation, respectively. Group I patients did not receive fentanyl and served as the control group. In Groups III and IV, blood pressures were not increased, except diastolic pressure in Group III, significantly postintubation compared with preinduction values; but Groups I, II, and V showed a significant increase (P < 0.05). The 1-min postintubation values of systolic, diastolic, and mean arterial pressure in Groups III and IV were less than those in the control group (P < 0.05). Increases of heart rate in Group IV were less (P < 0.05) than those in the control group, but significant differences were not observed in Groups II, III, and V. The number of patients with tachycardia and dysrhythmia was significantly smaller in Group IV than in the control group (P < 0.05). We conclude that the most effective time to administer fentanyl to protect circulatory responses to laryngoscopy and tracheal intubation is 5 min before tracheal intubation.

IMPLICATIONS

Fentanyl is often used to reduce the hemodynamic response to tracheal intubation. However, large doses may cause unwanted side effects. Administration of fentanyl at the optimal time reduces the dose required. Our results indicate that optimal injection time of fentanyl for intubation is 5 min before intubation.

Propofol attenuates ischemia-reperfusion injury in the isolated rat heart

The purpose of this study was to examine the direct effects of propofol on ischemia-reperfusion injury using an isolated Langendorff rat heart preparation. Hearts were perfused with Krebs-Henseleit (K-H) solution (control); intralipid; or 10, 30, and 100 microM propofol. Hearts were rendered globally ischemic for 25 min, then reperfusion was begun with K-H solution for 30 min. Treatment with 100 microM propofol delayed the onset of contracture during ischemia compared with control or intralipid treatments (6.4 +/- 2.1 vs 4.4 +/- 1.4 or 4.1 +/- 0.7 min, respectively; P < 0.05). During reperfusion, 100 microM propofol increased coronary flow and reduced lactate dehydrogenase release compared with control or intralipid treatments. After 30 min of reperfusion, left ventricular developed pressure (LVDP) returned to 55 and 76 mm Hg in the 30 and 100 microM propofol-treated groups, respectively, whereas LVDP was 39 mm Hg in the control group. The hearts treated with 100 microM propofol showed significantly lower left ventricular end-diastolic pressure compared with the control or intralipid groups 30 min after reperfusion (29 +/- 13 vs 48 +/- 5 or 48 +/- 11 mm Hg, respectively; P < 0.05). In histological evaluation, control and intralipid hearts had increased injury severity scores compared with hearts treated with 100 microM propofol (1.8 +/- 0.9 and 1.7 +/- 0.8 vs 1.0 +/- 0.7, respectively; P < 0.05). In conclusion, we suggest that propofol administered before and during global myocardial ischemia has cardioprotective effects on ischemia-reperfusion injury.

IMPLICATIONS

It is important to protect the heart from injury by ischemia and reperfusion. The current study demonstrates that in the isolated rat heart, propofol attenuates mechanical, biochemical, and histological changes causes by ischemia and reperfusion.

Blockade of myocardial ATP-sensitive potassium channels by ketamine

BACKGROUND

The adenosine triphosphate (ATP)-sensitive potassium (KATP) channel underlies the increase in potassium permeability during hypoxia and ischemia. The increased outward potassium current during ischemia may be an endogenous cardioprotective mechanism. This study was designed to determine the effects of ketamine on KATP channel in rat hearts.

METHODS

Inside-out and cell-attached configurations of patch-clamp techniques and 3 M potassium chloride-filled conventional microelectrodes were used to investigate the effect of ketamine on KATP channel currents in single rat ventricular myocytes and on the action potential duration of rat papillary muscles, respectively.

RESULTS

Ketamine inhibited KATP channel activity in rat ventricular myocytes in a concentration-dependent manner. In the inside-out patches, the concentration of ketamine for half-maximal inhibition and the Hill coefficient were 62.9 microM and 0.54, respectively. In a concentration-dependent manner, ketamine inhibited pinacidil- and 2,4-dinitrophenol-activated KATP channels in cell-attached patches. The application of ketamine to the intracellular side of membrane patches did not affect the conduction of single-channel currents of KATP channels. Ketamine increased the action potential duration, which was then shortened by pinacidil in a concentration-dependent manner.

CONCLUSIONS

Ketamine inhibited KATP channel activity in a concentration-dependent manner. These results suggest that ketamine may attenuate the cardioprotective effects of the KATP channel during ischemia and reperfusion in the rat myocardium.

Epidural morphine plus ketamine for upper abdominal surgery: improved analgesia from preincisional versus postincisional administration

Increased postoperative pain may be caused by central nervous system plasticity, which may be related to actions of N-methyl-D-aspartic acid (NMDA) receptors on neurons in the dorsal horn of the spinal cord. Opioids act mainly on presynaptic receptors and reduce neurotransmitter release, while ketamine antagonizes NMDA receptors and prevents wind-up and long-term potentiation. Thus, we postulated that central nervous system sensitization would be prevented more effectively by the preoperative use of these two drugs simultaneously, and the effect of preemptive analgesia would be demonstrated. Ketamine, 60 mg, and morphine, 2 mg, were injected epidurally through an indwelling catheter that was inserted at the T7-8 interspace in 60 ASA physical status class 1-2 patients. The drugs were injected before induction of anesthesia (Group 1; n = 30) or immediately after removal of a surgical specimen (Group 2; n = 30). An additional 2 mg of morphine was injected when the patients complained of resting pain. The analgesic effect was assessed by the time from first analgesic injection to second dose and the number of patients who needed supplemental injections. Complications were also noted. The duration of analgesia was longer (P < 0.01) in Group 1 (31.1 +/- 16.0 h) than in Group 2 (21.1 +/- 12.0 h), and the proportion of patients who needed supplemental injections was decreased (P < 0.05) in Group 1 (56.7%) compared with Group 2 (90.0%). The incidence of adverse effects was not different between the two groups. In conclusion, preoperative administration of morphine and ketamine is more effective in reducing postoperative pain than it is when given during the operation.

Masseter muscle atrophy after ostectomy of the mandibular angle in rabbits

In order to get information about changes in the masseter muscle when operations are performed on the mandibular angle area, we classified 70 New Zealand White rabbits into group O (ostectomy) and group D (dissection). In group O we performed unilateral ostectomy of the mandibular angle, while in group D we performed unilateral dissection of the masseter muscle limited to the mandibular angle area. Then we compared morphologic, histologic, and histochemical changes in experimental masseter muscles with those in normal control masseter muscles. We examined 5 rabbits in each group at the following intervals: 1, 2, 4, 6, 8, 12, and 24 weeks. In group D (dissection), there were no remarkable changes at all examinations. In group O (ostectomy), there was a 30 percent decrease in experimental muscle mass compared with control muscle. On examination of muscle fiber types, a decrease in type I fibers and an increase in type IIA and IIB fibers were noticed (p < 0.05). Each experimental muscle fiber became more irregularly and angularly shaped, and mean fiber area also was reduced. Sarcomere lengths of experimental muscle fibers were significantly reduced to 80 percent of control values (p < 0.05) during the first 4 weeks, but after 6 weeks they were lengthened to control values. Collagen and fibrin did not show much difference between experimental and control muscles. All these findings imply that masseter muscle atrophy after ostectomy of the mandibular angle is not due to connective-tissue changes but to individual muscle fiber atrophy accompanied by functional adaptation of sarcomeres and changes in muscle fiber types.

Induction chemotherapy with idarubicin plus N4-behenoyl-1-beta-D-arabinofuranosylcytosine in acute myelogenous leukemia: a newly designed induction regimen--a prospective, cooperative multicenter study

This report describes the results of induction chemotherapy with idarubicin (IDA) plus N4-behenoyl-1-beta-D-arabinofuranosylcytosine (BH-AC), a newly designed induction regimen, in cases of previously untreated acute myelogenous leukemia (AML). The study was conducted by the Multicenter Clinical Study Group of the Korean Biologic Response Modifier Society (KBRMS). From March 1994 through January 1995, 40 patients were treated. The median age was 30 years (range, 15 months to 65 years), with a distribution according to the French-American-British (FAB) classification of one MO, nine MI, 15 M2, six M3, four M4, and five M5 patients. Remission induction therapy consisted of IDA 12 mg/m2 intravenously (i.v.) over 30 minutes daily on days 1 to 3, in combination with BH-AC 300 mg/m2 over 4 hours daily on days 1 to 7 (in patients aged 41 to 65 years, BH-AC dosage was decreased to 200 mg/m2/d). Complete remission (CR) was achieved in 30 patients (75%), 22 by the first induction therapy and eight by the second induction therapy. Ten patients (25%) failed to respond to therapy, six due to resistant disease and four due to death caused by aplasia. The time to CR was 30 days, the median granulocytopenic period was 19 days, and the thrombocytopenic period was 24 days. All nonhematologic side effects such as nausea, vomiting, mucositis, skin eruption, liver and cardiac dysfunction, and neurotoxicity, were transient and tolerable. These data indicate an efficacy comparable to that of other combinations of IDA (or other anthracyclines) with cytosine arabinoside (Ara-C) for remission induction in AML.

Neglect of childhood strabismus: Keelung Ann-Lo Community ocular survey 1993-1995

Strabismus is a major cause of amblyopia. Parents not aware of the adverse outcome of untreated strabismus is thought to be a major reason of their affected child not being discovered earlier. An ocular survey was therefore conducted to examine the relative neglect of strabismus by the public, using myopia as a reference eye disorder. Specific objectives included estimating the prevalence of these ocular diseases, comparing the self-reported rate to the test-based rate, and investigating how much parents knew about these ocular diseases. Between 1993 and 1995, 862 elementary students in the first, third, and sixth grade at Keelung Ann-Lo Community were screened. The prevalence of manifest strabismus was 1.62% (95% CI = 1.19% approximately 2.05%). Of those with strabismus, three (21.4%) knew that they had strabismus. Neither the prevalence nor the self-known proportion of strabismus changed substantially with school grade, suggesting that the majority of strabismus afflicted children remain unrecognized during their elementary school years. The amblyopia proportion in those with tropia was 42.9% and reduced to 21.5% after abnormal refractive error was excluded. Of six knowledge statements about each ocular disorder, parents answered 2.13 (SD = 1.40) strabismus statements correctly, which was significantly less than their response on myopia statements (4.32 with SD = 1.24) (p < .0001). Onset age of strabismus was the question answered least correctly, implying that parents are not aware of the timing of treating strabismus. Our findings suggest that childhood strabismus was neglected by the public before the implementation of National Health Insurance (NHI). Should a similar study continued to be conducted in the future, the efficacy of NHI in the early recognition and treatment on childhood strabismus can be evaluated.