Dong-Hyeon Shin

Molecular Characterization of Methicillin-Resistant Staphylococcus aureus Isolates in Korea

ABSTRACT We used several molecular typing methods to analyze 196 methicillin-resistant Staphylococcus aureus (MRSA) and 139 methicillin-susceptible S. aureus (MSSA) isolates collected between 1996 and 2005. The sequence type 72 MRSA has increased in frequency in the community in the Republic of Korea and in hospitals in recent years.

Melatonin attenuates doxorubicin-induced testicular toxicity in rats.

This study investigated the protective effects of melatonin (MLT) against doxorubicin (DXR)‐induced testicular toxicity and oxidative stress in rats. DXR was given as a single intraperitoneal dose of 10 mg kg−1 body weight to male rats at 1 h after MLT treatment on day 6 of the study. MLT at 15 mg kg−1 body weight was administered daily by gavage for 5 days before DXR treatment followed by an additional dose for 5 days. Sperm analysis, histopathological examination and biochemical methods were used for this investigation. DXR caused a decrease in the weight of seminal vesicles, epididymal sperm count and motility and an increase in the incidence of histopathological changes of the testis. In addition, an increased malondialdehyde (MDA) concentration and decreased glutathione content, glutathione reductase (GR), glutathione‐S‐transferase (GST), superoxide dismutase (SOD) and catalase activities were observed. On the contrary, MLT treatment significantly ameliorated DXR‐induced testicular toxicity in rats. Moreover, MDA concentration and GR, GST and SOD activities were not affected when MLT was administered in conjunction with DXR. These results indicate that MLT had a protective effect against DXR‐induced testicular toxicity and that the protective effects of MLT may be due to both the inhibition of lipid peroxidation and increased antioxidant activity.

Evaluation of Subchronic Inhalation Toxicity of Dimethyl Disulfide in Rats

This study was carried out to investigate the potential subchronic inhalation toxicity of dimethyl disulfide (DMDS) via whole-body exposure in F344 rats. Groups of 10 rats of each sex were exposed to DMDS vapor by whole-body exposure at concentrations of 0, 5, 25, or 125 ppm for 6 h/day, 5 days/wk for 13 wk. All the rats were sacrificed at the end of treatment period. During the test period, clinical signs, mortality, body weights, food consumption, ophthalmoscopy, urinalysis, hematology, serum biochemistry, gross findings, organ weights, and histopathology were examined. At 25 ppm, a decrease in the body weight gain, food intake, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and blood urea nitrogen (BUN) was observed in the males, but not in the females. However, at 125 ppm, a decrease in the body weight gain, food intake, and thymus weight and an increase in the weights of adrenal glands were observed in both genders. Serum biochemical investigations revealed a decrease in the AST, ALT, BUN, creatine phosphokinase (CPK), and triglyceride levels and an increase in the glucose level. In contrast, no treatment-related effects were observed in the 5 ppm group. The toxic potency of DMDS was slightly higher in males than that in females. In these experimental conditions, the target organ was not determined in rats. The no-observed-adverse-effect concentration (NOAEC) was found to be 5 ppm, 6 h/day for male rats and 25 ppm, 6 h/day for female rats.

Developmental toxic potential of 1,3-dichloro-2-propanol in Sprague-Dawley rats.

This study investigated the potential adverse effects of 1,3-dichloro-2-propanol (1,3-DCP) on pregnant dams and the embryo-fetal development after maternal exposure on gestational days (GD) 6 through 19 in Sprague-Dawley rats. The test chemical was administered to pregnant rats by gavage at dose levels of 0, 10, 30, and 90mg/kg per day (n=10 for each group). All dams underwent Caesarean sections on GD 20, and their fetuses were examined for morphological abnormalities. Maternal toxicity was noted at 90mg/kg/day. Manifestations of toxicity included clinical signs of illness, lower body weight gain, decreased food intake, and increases in the weight of the adrenal glands and the liver. Developmental toxic effects including decreases in fetal body weight and increases in visceral and skeletal variations also occurred at the highest dose. At 30mg/kg, only a minimal maternal toxicity, including a decrease in maternal food intake and an increase in the liver weight, was observed. No adverse maternal or developmental effects were observed at 10mg/kg/day. These results revealed that a 14-day repeated oral dose of 1,3-DCP was minimally embryotoxic but not teratogenic at a maternal toxic dose (90mg/kg/day), and was not embryotoxic at a minimally maternal toxic dose (30mg/kg/day) in rats. Because the developmental toxicity of 1,3-DCP was observed only in the presence of maternal toxicity, it is concluded that the developmental findings observed in the present study are secondary effects to maternal toxicity. Under these experimental conditions, the no-observed-adverse-effect level of 1,3-DCP is considered to be 10mg/kg/day for dams and 30mg/kg/day for embryo-fetal development.

A case of disseminated Cryptococcosis with skin eruption in a patient with acute leukemia.

Disseminated cryptococcosis is a life-threatening infection caused by Cryptococcus neoformans and cutaneous dissemination occurs in 10?15% of patients. We report a case of a 49-y-old leukemic patient with disseminated cryptococcosis who presented with fever, headache, normal cerebrospinal fluid profile and multiple skin lesions mimicking molluscum contagiosum.Disseminated cryptococcosis is a life-threatening infection caused by Cryptococcus neoformans and cutaneous dissemination occurs in 10-15% of patients. We report a case of a 49-y-old leukemic patient with disseminated cryptococcosis who presented with fever, headache, normal cerebrospinal fluid profile and multiple skin lesions mimicking molluscum contagiosum.

Ruptured Klebsiella pneumoniae liver abscess after high‐dose cyclophosphamide for severe aplastic anemia

A 19‐year‐old woman with severe aplastic anemia who had previously failed antithymocyte globulin/cyclosporine A received high‐dose cyclophosphamide without bone marrow rescue. On day +14, she complained of right upper quadrant abdominal pain and fever. A CT scan of the abdomen showed multiple liver abscesses with rupture and Klebsiella pneumoniae was isolated from blood. In spite of aggressive antibiotic therapy, she rapidly deteriorated and died of overwhelming sepsis. To our knowledge, our patient is the first case of fatal ruptured liver abscess after high‐dose cyclophosphamide in a patient with severe aplastic anemia. Am. J. Hematol. 64:218–220, 2000.