Changes in the Occurrence of Gastrointestinal Infections after COVID-19 in Korea

Background@#After the global epidemic of coronavirus disease 2019 (COVID-19), lifestyle changes to curb the spread of COVID-19 (e.g., wearing a mask, hand washing, and social distancing) have also affected the outbreak of other infectious diseases. However, few studies have been conducted on whether the incidence of gastrointestinal infections has changed over the past year with COVID-19. In this study, we examined how the incidence of gastrointestinal infections has changed since COVID-19 outbreak through open data. @*Methods@#We summarized the data on the several viruses and bacteria that cause gastrointestinal infections from the open data of the Korea Disease Control and Prevention Agency for 3 years from March 2018 to February 2021 (from Spring 2018 to Winter 2020). Moreover, we confirmed three most common legal gastrointestinal infectious pathogens from March 2016. @*Results@#From March 2020, when the COVID-19 epidemic was in full swing and social distancing and personal hygiene management were heavily emphasized, the incidence of infection from each virus was drastically decreased. The reduction rates compared to the averages of the last 2 years were as follows: total viruses 31.9%, norovirus 40.2%, group A rotavirus 31.8%, enteric adenovirus 13.4%, astrovirus 7.0%, and sapovirus 12.2%. Among bacterial pathogens, the infection rates of Campylobacter and Clostridium perfringens did not decrease but rather increased in some periods when compared to the average of the last two years. The incidence of nontyphoidal Salmonella, Staphylococcus aureus, or enteropathogenic Escherichia coli somewhat decreased but not significantly compared to the previous two years. @*Conclusion@#The incidence of infection from gastrointestinal viruses, which are mainly caused by the fecal-to-oral route and require direct contact among people, was significantly reduced, whereas the incidence of bacterial pathogens, which have food-mediated transmission as the main cause of infection, did not decrease significantly.

Mini-Screws-Only Fixation Method for Small Fragments of Medial Malleolus Fractures

Background@#Open reduction and internal fixation is the standard treatment for a displaced medial malleolus fracture (MMFx), achieving ankle stability and bony union to prevent post-traumatic arthritis. Previous fixation techniques including tension band wiring and unicortical screw fixation are not optimal for fixation of small fragments in MMFx due to their small size and poor manipulability. Here, we describe a novel surgical method using mini-screws only for fixation of small fragments in MMFx. @*Methods@#We conducted a retrospective consecutive study of patients who underwent surgery using mini-screws for small fragment MMFx between April 2013 and March 2018. We reviewed the patients’ clinical characteristics and assessed the fracture features radiographically. Clinical outcomes were assessed by measuring the range of motion of both ankle joints and investigating symptomatic implants. We reviewed the radiographic outcomes of the medial malleolus and the functional outcomes using the Foot and Ankle Outcome Score (FAOS) at the last follow-up. @*Results@#Nine patients were included in the study. The minimal follow-up period was 27 months. There was no incidental bone breakage during the procedure. All MMFx healed without reduction loss, nonunion, or implant failure at the last follow-up. Two patients had mild osteoarthritic changes of the ankle joint. The mean FAOS score of the patients was 80.99 (range, 65.44–98.42). No patients required removal of the hardware. @*Conclusions@#Fixation of comminuted fractures of the medial malleolus using mini-screws for young adult patients is a straightforward and simple technique. Safe fixation of the anterior and posterior colliculi reduces the risk of implant irritation symptoms that necessitate implant removal.

Changes in the Occurrence of Gastrointestinal Infections after COVID-19 in Korea

Background@#After the global epidemic of coronavirus disease 2019 (COVID-19), lifestyle changes to curb the spread of COVID-19 (e.g., wearing a mask, hand washing, and social distancing) have also affected the outbreak of other infectious diseases. However, few studies have been conducted on whether the incidence of gastrointestinal infections has changed over the past year with COVID-19. In this study, we examined how the incidence of gastrointestinal infections has changed since COVID-19 outbreak through open data. @*Methods@#We summarized the data on the several viruses and bacteria that cause gastrointestinal infections from the open data of the Korea Disease Control and Prevention Agency for 3 years from March 2018 to February 2021 (from Spring 2018 to Winter 2020). Moreover, we confirmed three most common legal gastrointestinal infectious pathogens from March 2016. @*Results@#From March 2020, when the COVID-19 epidemic was in full swing and social distancing and personal hygiene management were heavily emphasized, the incidence of infection from each virus was drastically decreased. The reduction rates compared to the averages of the last 2 years were as follows: total viruses 31.9%, norovirus 40.2%, group A rotavirus 31.8%, enteric adenovirus 13.4%, astrovirus 7.0%, and sapovirus 12.2%. Among bacterial pathogens, the infection rates of Campylobacter and Clostridium perfringens did not decrease but rather increased in some periods when compared to the average of the last two years. The incidence of nontyphoidal Salmonella, Staphylococcus aureus, or enteropathogenic Escherichia coli somewhat decreased but not significantly compared to the previous two years. @*Conclusion@#The incidence of infection from gastrointestinal viruses, which are mainly caused by the fecal-to-oral route and require direct contact among people, was significantly reduced, whereas the incidence of bacterial pathogens, which have food-mediated transmission as the main cause of infection, did not decrease significantly.

Mini-Screws-Only Fixation Method for Small Fragments of Medial Malleolus Fractures

Background@#Open reduction and internal fixation is the standard treatment for a displaced medial malleolus fracture (MMFx), achieving ankle stability and bony union to prevent post-traumatic arthritis. Previous fixation techniques including tension band wiring and unicortical screw fixation are not optimal for fixation of small fragments in MMFx due to their small size and poor manipulability. Here, we describe a novel surgical method using mini-screws only for fixation of small fragments in MMFx. @*Methods@#We conducted a retrospective consecutive study of patients who underwent surgery using mini-screws for small fragment MMFx between April 2013 and March 2018. We reviewed the patients’ clinical characteristics and assessed the fracture features radiographically. Clinical outcomes were assessed by measuring the range of motion of both ankle joints and investigating symptomatic implants. We reviewed the radiographic outcomes of the medial malleolus and the functional outcomes using the Foot and Ankle Outcome Score (FAOS) at the last follow-up. @*Results@#Nine patients were included in the study. The minimal follow-up period was 27 months. There was no incidental bone breakage during the procedure. All MMFx healed without reduction loss, nonunion, or implant failure at the last follow-up. Two patients had mild osteoarthritic changes of the ankle joint. The mean FAOS score of the patients was 80.99 (range, 65.44–98.42). No patients required removal of the hardware. @*Conclusions@#Fixation of comminuted fractures of the medial malleolus using mini-screws for young adult patients is a straightforward and simple technique. Safe fixation of the anterior and posterior colliculi reduces the risk of implant irritation symptoms that necessitate implant removal.

MRI Assessment of Cerebral Small Vessel Disease in Patients with Spontaneous Intracerebral Hemorrhage

PURPOSE: Cerebral small vessel disease (SVD) is known to be associated with ischemic stroke, intracerebral hemorrhage (ICH), and cognitive impairment. In this retrospective observational study, we explored SVD markers on MRI relevant to spontaneous ICH. MATERIALS AND METHODS: The ICH group consisted of 150 consecutive patients with a first primary parenchymal ICH, and the control group consisted of 271 age- and sex-matched individuals who underwent brain MRI in a health care center. We compared cerebral microbleeds (CMBs), white matter hyperintensities (WMHs), enlarged perivascular space (EPVS), and lacunae in the ICH and control groups. RESULTS: A total of 1278 CMB lesions were identified in 121 of the 150 patients in the ICH group (80.6%), while 77 CMB lesions were found in 32 of the 271 individuals in the control group (11.8%). WMH and EPVS were more severe and lacunae were more frequent in the ICH patients than in the control group. When receiver operating characteristic (ROC) curves were plotted, number of CMBs most significantly predicted ICH. All imaging markers were significantly associated with ICH in every age group. The location of CMBs coincided with the location of ICH, and ICH volume correlated with CMB count. CONCLUSION: All MRI markers for SVD were worse in ICH patients than in healthy controls, and these markers were prominent even in young ICH patients. Lacunae, WMH, EPVS, and CMB should be considered as factors related with spontaneous ICH.

Lead, Mercury, and Cadmium Exposure in the Korean General Population

BACKGROUND: Lead (Pb), mercury (Hg), and cadmium (Cd) are well-known environmental pollutants. They are unnecessary in the biological processes of humans. This study was performed to estimate the representative background exposure levels to the metals by measuring concentrations in whole blood of the Korean general population. METHODS: This population-based cross-sectional study included 4,000 subjects (1,886 males and 2,114 females) 0–83 years of age in 2010 and 2011. Adult subjects (≥ 19 years of age) were collected by sex- and age-stratified probability method, and preschool- and school-aged subjects were recruited by a cluster sampling method. Written consent was provided prior to blood sampling. Pb and Cd blood concentrations were determined by a flameless atomic absorption spectrophotometry, and blood Hg was analyzed by a direct Hg analyzer. RESULTS: The geometric mean, median and 95th percentile of blood Pb was 1.82 µg/dL, 1.83 µg/dL, and 3.78 µg/dL, respectively. The respective values were 2.92 µg/L, 2.87 µg/L, 9.12 µg/L for Hg, and 0.56 µg/L, 0.59 µg/L, 2.20 µg/L for Cd. Blood Pb and Hg were higher in males than in females, but no sex difference was observed, respectively, in subjects 0–4 years of age for Pb and in subjects less than 20 years for Hg. However, blood Cd was higher in females than in males and no sex difference was observed in subjects < 30 years of age. CONCLUSION: This study provides representative data of human exposure to Pb, Hg, and Cd covering whole age groups of the general population in Korea.

The Association of Blood Concentrations of Healvy Metals and Blood Pressure in Residents Living Near Janghang Copper Smelter in Korea / 農村醫學 地域保健

OBJECTIVES: This study was conducted to evaluate a relationship between the blood concentrations of toxic metals and the blood pressure in people living near the copper smelter. METHODS: The study included 570 adults living within 4km of the smelter. We compared systolic and diastolic blood pressure between tertiary groups for blood cadmium, mercury and lead levels, respectively. Multiple regression analysis was performed to identify risk factors affecting systolic and diastolic blood pressures. RESULTS: In male subjects, there is a significant difference in the mean of systolic and diastolic blood pressure between tertiary groups of blood cadmium and mercury levels, but in women, there was no significant difference in the mean systolic and diastolic blood pressures in all tertiary groups of heavy metals. The results of multiple regression analysis showed that age, BMI, and cadmium concentration in men were risk factors for blood pressure. CONCLUSIONS: Residents living near the Janghang smelter showed high concentrations of blood lead and cadmium, suggesting that they were exposed to high concentrations of heavy metals released from the smelter in the past. Such exposure may have caused some blood pressure increase. Especially, the concentration of cadmium in the case of men and the concentration of mercury in blood in the case of women were found to be significantly related to the increase of blood pressure. The local population should be advised to make efforts to reduce exposure to environmental contaminants, in order to minimize cardiovascular disease, and to pay close attention to any health problems possibly related to toxic metal exposure.

Urinary arsenic species concentration in residents living near abandoned metal mines in South Korea

BACKGROUND: Arsenic is a carcinogenic heavy metal that has a species-dependent health effects and abandoned metal mines are a source of significant arsenic exposure. Therefore, the aims of this study were to analyze urinary arsenic species and their concentration in residents living near abandoned metal mines and to monitor the environmental health effects of abandoned metal mines in Korea. METHODS: This study was performed in 2014 to assess urinary arsenic excretion patterns of residents living near abandoned metal mines in South Korea. Demographic data such as gender, age, mine working history, period of residency, dietary patterns, smoking and alcohol use, and type of potable water consumed were obtaining using a questionnaire. Informed consent was also obtained from all study subjects (n = 119). Urinary arsenic species were quantified using high performance liquid chromatography (HPLC) and inductively coupled plasma mass spectrometry (ICP/MS). RESULTS: The geometric mean of urinary arsenic (sum of dimethylarsinic acid, monomethylarsonic acid, As3+, and As5+) concentration was determined to be 131.98 μg/L (geometric mean; 95% CI, 116.72–149.23) while urinary inorganic arsenic (As3+ and As5+) concentration was 0.81 μg/L (95% CI, 0.53–1.23). 66.3% (n = 79) and 21.8% (n = 26) of these samples exceeded ATSDR reference values for urinary arsenic (>100 μg/L) and inorganic arsenic (>10 μg/L), respectively. Mean urinary arsenic concentrations (geometric mean, GM) were higher in women then in men, and increased with age. Of the five regions evaluated, while four regions had inorganic arsenic concentrations less than 0.40 μg/L, one region showed a significantly higher concentration (GM 15.48 μg/L; 95% CI, 7.51–31.91) which investigates further studies to identify etiological factors. CONCLUSION: We propose that the observed elevation in urinary arsenic concentration in residents living near abandoned metal mines may be due to environmental contamination from the abandoned metal mine. TRIAL REGISTRATION: Not Applicable (We do not have health care intervention on human participants).

Environmental Exposure to Arsenic, Lead, and Cadmium in People Living near Janghang Copper Smelter in Korea

Concentrations of heavy metals exceed safety thresholds in the soil near Janghang Copper Refinery, a smelter in Korea that operated from 1936 to 1989. This study was conducted to evaluate the level of exposure to toxic metals and the potential effect on health in people living near the smelter. The study included 572 adults living within 4 km of the smelter and compared them with 413 controls group of people living similar lifestyles in a rural area approximately 15 km from the smelter. Urinary arsenic (As) level did not decrease according to the distance from the smelter, regardless of gender and working history in smelters and mines. However, in subjects who had no occupational exposure to toxic metals, blood lead (Pb) and cadmium (Cd) and urinary Cd decreased according to the distance from the smelter, both in men and women. Additionally, the distance from the smelter was a determinant factor for a decrease of As, Pb, and Cd in multiple regression models, respectively. On the other hands, urinary Cd was a risk factor for renal tubular dysfunction in populations living near the smelter. These results suggest that Janghang copper smelter was a main contamination source of As, Pb, and Cd, and populations living near the smelter suffered some adverse health effects as a consequence. The local population should be advised to make efforts to reduce exposure to environmental contaminants, in order to minimize potential health effects, and to pay close attention to any health problems possibly related to toxic metal exposure.

Urinary Arsenic Concentrations and their Associated Factors in Korean Adults

Arsenic (As) is a well-known human carcinogen and its dietary exposure has been found to be the major route of entry into general population. This study was performed to assess the body levels of As and their associated factors in Korean adults by analyzing total As in urine. Urine and blood samples were collected from 580 adults aged 20 years and older, who had not been exposed to As occupationally. Demographic information was collected with the help of a standard questionnaire, including age, smoking, alcohol intake, job profiles, and diet consumed in the last 24 hrs of the study. Total As, sum of As(III), As(V), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), in urine was determined using atomic absorption spectrometer involving hydride generation method. The geometric mean concentration of total As in urine was 7.10 microg/L. Urine As was significantly higher in men (7.63 microg/L) than in women (6.75 microg/L). Age, smoking, alcohol consumption, and job profiles of study subjects did not significantly affect the concentration of As in urine. No significant relationship was observed between body mass index (BMI), Fe, and total cholesterol in serum and urinary As. Urine As level was positively correlated with seaweeds, fishes & shellfishes, and grain intake. A negative correlation between urinary As level and HDL-cholesterol in serum and meat intake was observed. Overall, these results suggest that urinary As concentration could be affected by seafood consumption. Therefore, people who frequently consume seafood and grain need to be monitored for chronic dietary As exposure.

Physical Activity in Adolescence Has a Positive Effect on Bone Mineral Density in Young Men / 예방의학회지

OBJECTIVES: Little is yet known about the determinants of bone mineral density (BMD) in young adults. Thus, in this study, we aimed to determine the factors that have an impact on BMD in young men. METHODS: Questionnaires were sent out to 111 male medical students. Information on age, socio-economic status, medical history, lifestyle, physical activity during adolescence, school club participation, current physical activity, and dietary intake were collected by the survey. Height, weight, percent body fat and muscle mass were estimated by bioelectrical impedance, and BMD was obtained using calcaneal quantitative ultrasound. Using the Poisson regression model, prevalence ratios (PRs) were used to estimate the degree of association between risk factors and osteopenia. RESULTS: The height and current physical activity showed a correlation to the Osteoporosis Index. Among the categorized variables, past physical activity during adolescence (p=0.002) showed a positive effect on the bone mineral content. In the multivariate model, past physical activity (> or =1 time/wk) had a protective effect on osteopenia (PR, 0.37; 95% confidence interval [CI], 0.18 to 0.75) and present physical activity (1000 metabolic equivalent of task-min/wk) decreased the risk of osteopenia (PR, 0.64; 95% CI, 0.44 to 0.91). CONCLUSIONS: Past physical activity during adolescence is as important as physical activity in the present for BMD in young men.

Mercury induced the Accumulation of Amyloid Beta (Abeta) in PC12 Cells: The Role of Production and Degradation of Abeta

Extracellular accumulation of amyloid beta protein (Abeta) plays a central role in Alzheimer's disease (AD). Some metals, such as copper, lead, and aluminum can affect the Abeta accumulation in the brain. However, the effect of mercury on Abeta accumulation in the brain is not clear. Thus, this study was proposed to estimate whether mercury concentration affects Abeta accumulation in PC12 cells. We treated 10, 100, and 1000 nM HgCl2 (Hg) or CH3HgCl2 (MeHg) for 48 hr in PC12 cells. After treatment, Abeta40 in culture medium increased in a dose- and time-dependent manner. Hg and MeHg increased amyloid precursor protein (APP), which is related to Abeta production. Neprilysin (NEP) levels in PC12 cells were decreased by Hg and MeHg treatment. These results suggested that Hg induced Abeta accumulation through APP overproduction and reduction of NEP.

Goodness-of-Fits of the Spirometric Reference Values for Koreans and USA Caucasians to Spirometry Data from Residents of a Region within Chungbuk Province / 결핵및호흡기질환

BACKGROUND: Korean regression models for spirometric reference values are different from those of Americans. Using spirometry results of Korean adults, goodness-of-fits of the Korean and the USA Caucasian regression models for forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were compared. METHODS: The number of study participants was 2,360 (1,124 males and 1,236 females). Spirometry was performed under the guidelines of the American Thoracic Society and the European Respiratory Society. After excluding unsuitable participants, spirometric data for 729 individuals (105 males and 624 females) was included in the statistical analysis. The estimated FVC and FEV1 values were compared with those measured. Goodness-of-fits for Korean and USA Caucasian models were compared using an F-test. RESULTS: In males, the expected values of FVC and FEV1 using the Korean model were 12.5% and 5.7% greater than those measured, respectively. The corresponding values for the USA Caucasian model were 3.5% and 0.6%. In females, the difference in FVC and FEV1 were 13.5% and 7.7% for the Korean model, and 6.3% and 0.4% for the USA model, respectively. Goodness-of-fit for the Korean model regarding FVC was not good to the study population, but the Korean regression model for FEV1, and the USA Caucasian models for FVC and FEV1 showed good fits to the measured data. CONCLUSION: These results suggest that the USA Caucasian model correlates better to the measured data than the Korean model. Using reference values derived from the Korean model can lead to an overestimation regarding the prevalence of abnormal lung function.

Efficacy of Hydrogel Mask with 2% Arbutin for Melasma / 대한피부과학회지

BACKGROUND: Melasma is a common, acquired, symmetrical hypermelanosis that occurs on sun exposed areas of the skin. It is more prevalent among Asian women than among Caucasian women. Many different treatment modalities have been used with various efficacies, but none of them have been completely satisfactory. Arbutin is a naturally occurring gluconopyranoside that may reduce tyrosinase activity, which is a rate-limiting enzyme for melanin production. OBJECTIVE: The purpose of this study was to investigate the depigmenting effect and safety of a mask that contains 2% arbutin for the treatment of melasma. METHODS: A total of 54 female volunteers with melasma were enrolled in this randomized, double-blind, 8-week treatment study. The patients were instructed to apply an arbutin-containing mask or an arbutin-free mask once a day for 8 weeks. The assessment of outcomes included the Melasma Area and Severity Index (MASI) score, colorimetric value (L*), overall patient satisfaction and investigator assessment score (evaluated using photography). RESULTS: The arbutin-containing mask significantly increased the right and left colorimetric values (L*) after the 8-week treatment (p0.05). The arbutin mask scored better than the control in patient satisfaction and investigator assessment. No significant adverse reactions were observed. CONCLUSION: The arbutin mask appears to be effective and well-tolerated when used for the treatment of melasma.

Effect of Amrinone, a Selective Inhibitor of Phosphodiesterase III, on PMNs-induced Cardiac Dysfunction in Ischemia/reperfusion

Ischemia followed by reperfusion in the presence of polymorphonuclear leukocytes (PMNs) results in a marked cardiac contractile dysfunction. Amrinone, a specific inhibitor of phosphodiesterase 3, has an antioxidant activity against PMNs. Therefore, we hypothesized that amrinone could attenuate PMNs-induced cardiac dysfunction by suppression of reactive oxygen species (ROS) produced fby PMNs. In the present study, we examined the effects of amrinone on isolated ischemic (20 min) and reperfused (45 min) rat hearts perfused with PMNs. Amrinone at 25microM, given to hearts during the first 5 min of reperfusion, significantly improved coronary flow, left ventricular developed pressure (P< 0.001), and the maximal rate of development of left ventricular developed pressure (P< 0.001), compared with ischemic/reperfused hearts perfused with PMNs in the absence of amrinone. In addition, amrinone significantly reduced myeloperoxidase activity by 50.8%, indicating decreased PMNs infiltration (p< 0.001). Superoxide radical and hydrogen peroxide production were also significantly reduced in fMLP- and PMA-stimulated PMNs pretreated with amrinone. Hydroxyl radical was scavenged by amrinone. fMLP-induced elevation of [Ca2+]i was also inhibited by amrinone. These results provide evidence that amrinone can significantly attenuate PMN-induced cardiac contractile dysfunction in the ischemic/ reperfused rat heart via attenuation of PMNs infiltration into the myocardium and suppression of ROS release by PMNs.

Acute Toxicity of Arsenic in Rats and Mice / 대한산업의학회지

OBJECTIVES: Arsenic (As) is ubiquitously distributed in the environment and is known as a human carcinogen. In this study, acute As toxicity at lethal dosage in rats and mice was evaluated, and As-induced hepatotoxicity was characterized. METHODS: Male Sprague-Dawley rats, male ICR mice and trivalent inorganic As, sodium arsenite, were used in this experiment. LD50 and LD100 were calculated from 24-hour lethality after the single subcutaneous administration of As into rats and mice. Serum and liver were collected from the surviving animals. The activities of ALT, AST and gamma-GT in serum were determined, and the concentrations of MDA, GSH and CYP450 in liver were analyzed. RESULTS: The LD50 and LD100 of sodium arsenite were calculated as 12 mg/kg and 13 mg/kg for rats, and 16.5 mg/kg and 19 mg/kg for mice, respectively. Thus, the rat was more susceptible than the mouse to the acute lethal toxicity of As. The histopathological changes induced by As were similar between rats and mice. AST was increased in high-dose As-treated rats and mice, whereas ALT was increased in high-dose As-treated mice but not in rats. gamma-GT was not significantly changed between the two animal groups. As increased lipid peroxidation, but decreased GSH and CYP450 in the liver of both rats and mice, in dose-dependent patterns. These results indicate that oxidative stress might be one of the mechanisms in As-induced hepatotoxicity. CONCLUSION: Rats were more susceptive than mice to acute As toxicity, and oxidative stress might play a part in liver injury induced by As.

Age-dependent Effect of Metabolism and Testicular Toxicity to di(2-ethylhexyl) Phthalate / 대한산업의학회지

OBJECTIVES: The purpose of this study was to evaluate the age-dependent response of testicular toxicity and the mechanism of di(2-ethylhexyl) phthalate (DEHP) induced testicular toxicity. METHODS: DEHP was administered orally in doses of 0, 1.0 and 2.0 g/kg/day, for 7 days, to 3, 6 and 9 week-old Sprague-Dawley rats. Testicular weight and sperm head counts, plasma level of DEHP, mono(2-ethylhexyl) phthalate (MEHP) and testicular lipid peroxidation were measured. Histopathological changes in the testis were observed. RESULTS: Reductions in weight gains, and relative testis weights, were observed in the 3 week-old rats in a dose-dependent manner, but not in the 6 and 9 week-old rats, compared to those of the control rats. Sperm head counts were decreased in the 6 week-old rats exposed to 2.0 g/kg/day, but not in the 9 week-old rats. Testicular atrophy and significant size reduction of the seminiferous tubule were observed in a dose-dependent manner in the 3 week-old rats. The plasma concentrations of MEHP were higher than those of DEHP, with these levels being most elevated in the younger rats. Lipid peroxidation, following exposed to DEHP, was increased in a dose-dependent manner in the 3 week-old, but with no changes in the 6 and 9 week-old rats. CONCLUSIONS: Our results suggest the age related difference observed in the testicular response to the oral administration of DEHP may be due to the metabolism, and that oxidative stress may be related to the mechanism of DEHP induced testicular toxicity.

Age-dependent Effect of Metabolism and Testicular Toxicity to di(2-ethylhexyl) Phthalate / 대한산업의학회지

OBJECTIVES: The purpose of this study was to evaluate the age-dependent response of testicular toxicity and the mechanism of di(2-ethylhexyl) phthalate (DEHP) induced testicular toxicity. METHODS: DEHP was administered orally in doses of 0, 1.0 and 2.0 g/kg/day, for 7 days, to 3, 6 and 9 week-old Sprague-Dawley rats. Testicular weight and sperm head counts, plasma level of DEHP, mono(2-ethylhexyl) phthalate (MEHP) and testicular lipid peroxidation were measured. Histopathological changes in the testis were observed. RESULTS: Reductions in weight gains, and relative testis weights, were observed in the 3 week-old rats in a dose-dependent manner, but not in the 6 and 9 week-old rats, compared to those of the control rats. Sperm head counts were decreased in the 6 week-old rats exposed to 2.0 g/kg/day, but not in the 9 week-old rats. Testicular atrophy and significant size reduction of the seminiferous tubule were observed in a dose-dependent manner in the 3 week-old rats. The plasma concentrations of MEHP were higher than those of DEHP, with these levels being most elevated in the younger rats. Lipid peroxidation, following exposed to DEHP, was increased in a dose-dependent manner in the 3 week-old, but with no changes in the 6 and 9 week-old rats. CONCLUSIONS: Our results suggest the age related difference observed in the testicular response to the oral administration of DEHP may be due to the metabolism, and that oxidative stress may be related to the mechanism of DEHP induced testicular toxicity.

The Effects of Diethyldithiocarbamate on the Metabolism and Hepatotoxicity of Trichloroethylene / 대한산업의학회지

OBJECTIVES: The purpose of this study was to evaluate the trichloroethylene (TCE) metabolism, acute toxicity, and the effects of diethyldithiocarbamate (DDTC) on the acute toxicity in TCE-intoxicated rats. METHODS: TCE was administered orally at doses of 600, 1,200 and 2,400 mg/kg of body weight following pretreatment with either saline or 500 mg/kg of DDTC. 12 hours after administration of TCE, the concentrations of TCE, trichloroacetic acid (TCA) and trichloroethanol (TCEOH) in the blood and solid organs, and the histopathological changes in each organ were examined. RESULTS: The level of CYP2E1 markedly decreased in the DDTC-pretreated groups. The CYP2E1 content in the TCE-treated rats increased in a dose-dependent manner. The concentrations of TCE and TCEOH were highest in the liver, and the level of TCA was highest in the blood. The DDTC-pretreated rats had a markedly increased level of TCE and decreased levels of TCA and TCEOH, than the rats pretreated with saline. These findings indicated that CYP2E1 was important in the metabolism of TCE. From the histopathological findings, centrilobular necrosis was observed in the livers of the TCE-treated rats, but no significant change was found in those rats pretreated with DDTC. CONCLUSIONS: DDTC is considered to be effective in protecting TCE-induced hepatic damage because it inhibits the TCE metabolism.

The Protective Effects of Garlic against Carbon tetrachloride-induced Hepatotoxicity / 예방의학회지

OBJECTIVES: The purpose of this study was to find the protective effects of garlic on the halogenated hydrocarbon induced hepatotoxicities, and the possible protection mechanisms involved. METHODS: Male Sprague-Dawley rats received garlic (0.5 %) or regular diet, for 4 weeks. This was followed by a single dose of corn oil (the controls), carbon tetrachloride (400mg/kg body weight) and trichloroethylene (2,000mg/kg body weight) being administered to each diet group. Blood samples were collected 24 hours following the administration, and the serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities measured. The liver samples were studied for their cytochrome P450 and CYP2E1 contents, lipid peroxidation and histopathology. RESULTS: The results for the group receiving the 0.5 % garlic diet showed a slight decrease of CYP2E1 expression compared with the regular diet group. Carbon tetrachloride was significantly decreased the CYP2E1 contents in both the regular and garlic diet groups, but the trichloroethylene remained unchanged. Garlic did not decrease the lipid peroxidation of the liver in the control group, but attenuated the increase of lipid peroxidation caused by carbon tetrachloride. Garlic attenuated the increase of both the serum AST and ALT activities caused by carbon tetrachloride. The histopathological observations also showed that garlic attenuated centrilobular necrosis and vacuolar degenerative changes significantly in the carbon tetrachloride treated group. Conclusions : The results indicate that garlic attenuates the carbon tetrachloride-induced hepatotoxicity, through the prevention of the metabolic activation and lipid peroxidation.