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Biomedical subjects

N Y Lee

Publications and source records attributed to N Y Lee.

28 records · Page 2Linked to original sources
PubMed1999

Spread of drug-resistant Streptococcus pneumoniae in Asian countries: Asian Network for Surveillance of Resistant Pathogens (ANSORP) Study.

Antimicrobial susceptibility of 996 isolates of Streptococcus pneumoniae from clinical specimens was investigated in 11 Asian countries from September 1996 to June 1997. Korea had the greatest frequency of nonsusceptible strains to penicillin with 79.7%, followed by Japan (65.3%), Vietnam (60.8%), Thailand (57.9%), Sri Lanka (41.2%), Taiwan (38.7%), Singapore (23.1%), Indonesia (21.0%), China (9.8%), Malaysia (9.0%), and India (3.8%). Serotypes 23F and 19F were the most common. Pulsed-field gel electrophoresis (PFGE) of 154 isolates from Asian countries showed several major PFGE patterns. The serotype 23F Spanish clone shared the same PFGE pattern with strains from Korea, Japan, Singapore, Taiwan, Thailand, and Malaysia. Fingerprinting analysis of pbp1a, pbp2x, and pbp2b genes of 12 strains from six countries also showed identical fingerprints of penicillin-binding protein genes in most strains. These data suggest the possible introduction and spread of international epidemic clones into Asian countries and the increasing problems of pneumococcal drug resistance in Asian countries for the first time.

Aminoacyltransferases↗
PubMed1999

Role of genotypic analysis of the thymidine kinase gene of herpes simplex virus for determination of neurovirulence and resistance to acyclovir.

Mutations in the thymidine kinase (TK) gene of herpes simplex virus (HSV) have been associated with resistance to acyclovir (ACY) and possible recognition of neurotropic strains. We sequenced a 335-bp segment of the TK gene to determine the frequency of mutations in HSV strains recovered from dermal, genital, and cerebrospinal fluid (CSF) specimens (n = 200; 102 HSV type 1 [HSV-1] 98 HSV-2 strains). Four polymorphic sites were detected in HSV-1 strains; C513T, A528G, C575T, and C672T. Among the polymorphisms, only C575T resulted in a change of amino acid sequence (residue 192, Ala-->Val). For HSV-2 strains, only one polymorphism (G420T) which resulted in an amino acid substitution (residue 139, Leu-->Phe) was detected. Phenotypic determination of resistance to ACY by a plaque reduction assay of 48 HSV isolates was not correlated with the sequence results of 11 strains in that 7 of these with genotypic polymorphisms were susceptible to the drug in vitro. In addition, of 32 ACY-resistant HSV strains, 28 (87.5%) had no polymorphisms detected in the 335-bp amplicon of the TK gene. There was no statistical difference in the frequency of polymorphisms according to the source of the specimens. We conclude that the detection of nucleic acid polymorphisms in a previously implicated 335-bp segment of the TK gene cannot be interpreted as indicative of either ACY resistance or neurotropism of HSV strains from dermal, genital, and CSF sources.

Acyclovir↗
PubMed1999

Clinical characteristics of acute viral lower respiratory tract infections in hospitalized children in Seoul, 1996-1998.

This study was performed to investigate the etiologic agents, age distribution, clinical manifestations and seasonal occurrence of acute viral lower respiratory tract infections in children. We confirmed viral etiologies using nasopharyngeal aspirates in 237 patients of the ages of 15 years or younger who were hospitalized for acute lower respiratory tract infection (ALRI) from March 1996 to February 1998 at Samsung Seoul Hospital, Seoul, Korea. The overall isolation rate was 22.1%. The viral pathogens identified were adenovirus (12.7%), influenza virus type A (21.1%), -type B (13.9%), parainfluenza virus type 1 (13.5%), -type 2 (1.3%), -type 3 (16.0%) and respiratory syncytial virus (21.5%). The occurrence of ALRIs was highest in the first year of life, although parainfluenza virus type 1 infection occurred predominantly in the second year of life and influenza virus caused illnesses in all age groups. The specific viruses are frequently associated with specific clinical syndromes of ALRI. The respiratory agents and associated syndromes frequently have characteristic seasonal patterns. This study will help us to estimate the etiologic agents of ALRI, and establish a program for the prevention and treatment. An annual nationwide survey is necessary to understand the viral epidemiology associated with respiratory illnesses in Korea.

Acute Disease↗
PubMed1998

Korean Nationwide Surveillance of Antimicrobial Resistance of bacteria in 1997.

Antimicrobial-resistant bacteria are known to be prevalent in tertiary-care hospitals in Korea. Twenty hospitals participated to this surveillance to determine the nationwide prevalence of resistance bacteria in 1997. Seven per cent and 26% of Escherichia coli and Klebsiella pneumoniae were resistant to 3rd-generation cephalosporin. Increased resistance rates, 19% of Acinetobacter baumannii to ampicillin/sulbactam, and 17% of Pseudomonas aeruginoa to imipenem, were noted. The resistance rate to fluoroquinolone rose to 24% in E. coli, 56% in A. baumannii and 42% in P. aeruginosa. Mean resistance rates were similar in all hospital groups: about 17% of P. aeruginosa to imipenem, 50% of Haemophilus influenzae to ampicillin, 70% of Staphylococcus aureus to methicillin, and 70% of pneumococci to penicillin. In conclusion, nosocomial pathogens and problem resistant organisms are prevalent in smaller hospitals too, indicating nosocomial spread is a significant cause of the increasing prevalence of resistant bacteria in Korea.

Bacterial Physiological Phenomena↗
PubMed1997

Detection of epidermal growth factor receptor in the serum of gastric carcinoma patients.

BACKGROUND: Epidermal growth factor receptor (EGFR) is overexpressed in various malignancies including carcinoma of the breast, lung, esophagus, cervix, and stomach. In patients with gastric carcinoma, its overexpression may be associated with advanced stage and poor prognosis. METHODS: The levels of EGFR extracellular domain were determined in serum from 40 gastric carcinoma patients using enzyme-linked immunosorbent assay. Serum EGFR levels were measured in 5 Stage I, 2 Stage II, 6 Stage III, and 27 Stage IV patients, and 29 healthy controls. RESULTS: The mean serum level for EGFR in the gastric carcinoma patients was significantly elevated compared with that of healthy controls (681 +/- 226 fmol/mL vs. 440 +/- 46 fmol/mL; P < 0.0001). Thirty-one patients with gastric carcinoma (77.5%) showed elevated EGFR levels above a cutoff value of 532 fmol/mL (defined as 2 standard deviations above the mean of the controls). No significant association was noted between positivity of EGFR and gender, age, stage, and tumor differentiation. CONCLUSIONS: The authors believe that serum EGFR could be useful as a tumor marker of gastric carcinoma for diagnosis, prognosis, follow-up after surgery, and monitoring patient response to chemotherapy.

Adult↗
PubMed1995

Heparin-like anticoagulant activity of sulphonated poly(ethylene oxide) and sulphonated poly(ethylene oxide)-grafted polyurethane.

Sulphonated poly(ethylene oxide) (PEO-SO3) and PEO-SO3-grafted polyurethane (PU-PEO-SO3) were prepared by bulk modification and their anticoagulant and heparin-like activities were investigated. Anticoagulant activity measured by activated partial thromboplastin time of PU-PEO-SO3 displayed 2%, whereas that of PEO-SO3 itself reached 14% as compared to free heparin. In addition, the anticoagulant effects of these sulphonated polymers were not due to factor Xa inhibition but mainly thrombin inhibition. From the clotting time measurements using reptilase instead of thrombin and antithrombin III (AT III), PEO-SO3 and PU-PEO-SO3 indicated heparin-like activity which represents both prolonged thrombin time (TT) and normal reptilase time and increased TT in the presence of AT III. Thrombin was also neutralized by sulphonated polymers to a great extent. Therefore, the anticoagulant and heparin-like activities of PEO-SO3 and PU-PEO-SO3 seem to contribute to their improved blood compatibility.

Anticoagulants↗
PubMed1992

A family case of beta-thalassemia minor and hemoglobin Queens: alpha 34 (B15) Leu-Arg.

We report a Korean family case of beta-thalassemia minor and Hb Queens. This is the first case report of Hb Queens in Korea. A 43-year-old male and his four family members had beta-thalassemia minor which is very rare in Korea. Incidentally, an alpha chain variant with a high isoelectric point was also found in two other family members without clinical problems and was finally identified as alpha 34 (B15) Leu-Arg or Hemoglobin Queens.

Adult↗
PubMed1984

The mechanism of diarrhoea resulting from pelvic and abdominal radiotherapy; a prospective study using selenium-75 labelled conjugated bile acid and cobalt-58 labelled cyanocobalamin.

An attempt was made to elucidate the mechanism of diarrhoea resulting from pelvic and abdominal radiotherapy in a prospective study of 10 patients undergoing treatment for curable pelvic malignant tumours using the synthetic trihydroxy 75Se-labelled conjugated bile acid, SeHcat and 58Co-labelled cyanocobalamin (58Co Vit B12). Evidence of malabsorption of vitamin B12 measured as a significant fall in whole body percentage retention of 58Co Vit B12 from baseline levels was found in all nine patients who developed diarrhoea during radiotherapy. Only four out of these nine patients also had malabsorption of the trihydroxy conjugated bile acid, cholic acid, measured as a significant fall in SeHcat whole body percentage retention and these patients had the most severe diarrhoea. The findings are discussed in the light of what is known about the pathophysiology of diarrhoea during pelvic and abdominal radiotherapy and lend support to previous work which implicated increased bowel motility in the pathogenesis of radiation-induced diarrhoea. The hypothesis that local neuroendocrine mechanisms in the gut may be involved is put forward, with possible implications for treatment.

Adult↗
PubMed1979

Evidences suggestive of no intestinal nitrogen fixation for improving protein nutrition status in sweet potato eaters.

Total of seven teenagers and two adults were given sweet potato diets that supplied slightly below requirement levels of protein for 32 (experiment 1) or 53 days (experiment 2) in two separate experiments. In experiment 1 and during the first 36 days of experiment 2, nitrogen (N) balance studies with the teenagers were conducted with 0.67 and 0.71 g of protein per kilogram of body weight, respectively. Results of the N balances including skin N loss were -0.5 mg N/kg per day in experiment 1 and -3.2 mg N/kg per day in experiment 2. Two adults were given 0.63 g/kg of protein and gave average N balance of +6.0 mg N/kg per day (experiment 2), however, one of them had a slightly negative cumulative N balance if miscellaneous N losses were included in calculation. Plasma urea N of both teenagers and adults decreased significantly from 8 to 11 to 2 to 3 mg/100 ml in experiment 2. After 32 or 53 days on the sweet potato diets, the plasma free amino acid pattern of the teenager subjects showed abnormality. Furthermore, the subjects were easier to get fatigue by physical exercise, and took longer nap due to sleepiness during the latter days of the experiments. Thus, although the mean hemoglobin, hematocrit, plasma total protein, and plasma albumin levels were within the normal ranges, the protein nutrition status of the teenagers and one of the two adults was considered to be not normal. The results suggested that intestinal N-fixation that was proposed by several investigators to occur in sweet potato eaters probably did not occur. The subjects' feces were examined in vitro for the ability of N-fixation with negative results. During the last 17 days of experiment 2 the effect of excess calorie on N balance was examined.

Adolescent↗