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Biomedical subjects

Y Chong

Publications and source records attributed to Y Chong.

At least 73 records · Page 4Linked to original sources
PubMed1992

Production of monoclonal antibody to a phenolic glycolipid of Mycobacterium tuberculosis and its use in detection of the antigen in clinical isolates.

A monoclonal antibody (MAbIII604) specific to phenolic glycolipid Tb (PGL-Tb), a Mycobacterium tuberculosis-specific antigen, was produced and used in the detection of the antigen. MAbIII604 reacted with the PGL-Tb antigen but not with other phenolic glycolipids from Mycobacterium leprae, M. bovis, and M. kansasii, thus indicating the specificity of the monoclonal antibody to PGL-Tb. A dot enzyme-linked immunosorbent assay with MAbIII604 was employed to detect the PGL-Tb antigen in lipids purified from M. tuberculosis clinical isolates. Of 50 isolates, 32 (64.0%) showed clear evidence of the PGL-Tb antigen by the dot enzyme-linked immunosorbent assay, but there were marked variations in the intensities and sizes of spots. This suggests differences in PGL-Tb antigen production among M. tuberculosis strains even when they are grown in the same culture media and conditions. This was most evident from the fact that in only eight (16.0%) of the isolates examined was the PGL-Tb antigen detectable by thin-layer chromatography, which is much less sensitive for the detection of glycolipid antigens. This study shows that monoclonal antibodies specific to PGL-Tb are useful in detecting the antigen in lipid extracts and that there is a marked variation in the PGL-Tb production among M. tuberculosis clinical isolates.

Antibodies, Bacterial↗
PubMed1992

Pyogenic arthritis of the hip due to Campylobacter fetus--a case report.

Septic arthritis of the hip caused by Campylobacter fetus subsp. fetusis very rare. The authoris isolated C. fetus subsp. fetus from a specimen of the left hip. The patient was a 53-year old man with a history of heavy drinking, diabetes, and chronic hepatitis, and had been suffering from avascular necrosis of both femoral heads. It was considered that the organism invaded already damaged tissue of the joint. The patient was treated with intravenous antibiotics and later received successful total hip replacement.

Arthritis, Infectious↗
PubMed1992

Detection of Mycobacterium tuberculosis in clinical samples from patients with tuberculosis or other pulmonary diseases by polymerase chain reaction.

Polymerase chain reaction (PCR) using primers targeting the IS6110 repetitive sequence was employed to detect Mycobacterium tuberculosis in 228 samples from patients with tuberculosis or other pulmonary diseases and controls, and the results were compared with culture and clinical findings. None of culture negative samples from 17 healthy controls were PCR positive. Of 109 active tuberculosis patients under chemotherapy, 88 (80.7%) were PCR positive and were significantly higher than 63 (57.8%) positive by culture. Fifty-nine (93.7) of 63 culture positive and 29 (63.0%) of 46 culture negative specimens contained M. tuberculosis detectable by PCR. In 41 specimens from inactive tuberculosis patients who visited to the chest clinic because of chest problems, 16 (39.0%) also gave PCR positive results. In addition, 14 (46.7%) of 30 specimens submitted for M. tuberculosis culture from patients with pulmonary diseases were PCR positive. Presumptive diagnosis of these PCR positive patients was bronchitis, pneumonia, bronchial asthma, etc. Therefore, this study suggests that PCR is sensitive and specific in detecting M. tuberculosis in clinical specimens. However, the interpretation of the PCR results in specimens from patients with pulmonary diseases should be done cautiously in areas with a high prevalence of tuberculosis.

Base Sequence↗
PubMed1991

Lactobacillus casei subspecies casei endocarditis--a case report.

Lactobacillus sp., generally considered to be a harmless indigenous bacteria of the mucous membrane, occasionally causes serious infections. Lactobacillus endocarditis is a very rare disease, and no case has been reported in Korea. Gram-positive bacilli were isolated from blood cultures of a 41-year-old man with clinically suspected subacute bacterial endocarditis. The patient had a dental procedure 3 months prior to the infection. The isolate was identified as L. casei subsp. casei based on the cultural characteristics and gas liquid chromatography of metabolic products. The patient was treated with ampicillin and improved. When Lactobacillus is isolated from the blood of an endocarditis patient, the significance should be seriously considered.

Adult↗
PubMed1991

Salmonella enterica subspecies diarizonae bacteremia in an infant with enteritis--a case report.

The septicemia caused by the Arizona group organism is rare and usually observed in adults with underlying diseases. In Korea, Salmonella infection is common, but a report of Arizona infection is unknown. We isolated S. entercia subsp. diarizonae from blood of a 6-month-old infant. The serovar was determined as 28:z10:-, a rare one in America. The isolate was susceptible to ampicillin, chloramphenicol, cotrimoxazole and others. The patient rapidly recovered with ampicillin and gentamicin therapy. Clinical laboratories should consider that the infection exists in Korea and should attempt to isolate and identify Arizona organism in certain patients.

Bacteremia↗
PubMed1990

Evaluation of thiol broth for the culture of Salmonella typhi and other bacteria from blood.

Thiol broth is known to neutralize various antimicrobial agents. Positivity of growth of various species of bacteria from blood in thiol broth was reported as similar to that in tryptic soy broth (TSB). As blood cultures are often used for the diagnosis of typhoid fever, and as patients may receive antimicrobial therapy before blood culture, the positivity and rapidity of growth of Salmonella typhi in thiol broth were compared to those in TSB. Routine blood culture samples from Yonsei Medical Center patients were inoculated in 50-ml amounts of TSB and thiol broth. The media were prepared from dehydrated products and did not contain CO2, but TSB contained 0.025% sodium polyanethol sulfonate (SPS). Growth of S. paratyphi-A, Klebsiella pneumoniae, Enterobacter sp., Serratia marcescens and alpha-hemolytic Streptococcus were similar in both media. However, greater positivity and shorter incubation time for macroscopic detection were noted in TSB with S. typhi, Escherichia coli and Staphylococcus aureus. It is concluded that thiol broth is inferior to TSB plus SPS for the culture of S. typhi from blood.

Bacteriological Techniques↗
PubMed1990

Production of monoclonal antibodies to lipoarabinomannan-B and use in the detection of mycobacterial antigens in sputum.

Tuberculosis has traditionally been confirmed by AFB staining or culturing Mycobacterium tuberculosis from clinical specimens. However, because of the low sensitivity of the sputum smear examination and of the delayed report in culturing, the conventional methods for detection of M. tuberculosis have not been always satisfactory. In an attempt to develop an alternate tool, this study was initiated to produce monoclonal antibodies (MAb) to lipoarabinomannan B (LAM-B) antigen and to use the antibodies in detecting mycobacteria. In this study, five monoclonal antibodies specific to LAM-B were produced; LAM701 (IgG3), LAM138 (IgM), LAM204 (IgM), LAM302 (IgM), and LAM604 (IgM). A sandwich enzyme-linked immunosorbent assay (ELISA) was developed for detecting LAM-B and other mycobacterial antigens using the monoclonal antibodies. With the MAb LAM701, the minimal detectable concentration was 1.0 ng/ml for LAM-B, and 1.0 microgram/ml for M. tuberculosis whole cells, respectively. When 14 clinical specimens proven to contain AFB by smear staining or culture were examined, ten (71.4%) were positive by the sandwich ELISA; in contrast, sputum smear examination gave positive results in only six (42.9%) specimens. Meanwhile, none of 25 specimens with no evidence of AFB were positive by the sandwich ELISA using the MAb LAM701. Although further evaluations are required, this study suggests that the monoclonal antibodies to LAM-B may be useful in detecting mycobacteria from clinical specimens.

Antibodies, Monoclonal↗
PubMed1989

Diagnostic usefulness of Vi-indirect fluorescent antibody test(Vi-IFAT) for typhoid fever--a prospective study.

Although the confirmative diagnosis of typhoid fever is by culture of the causative organism, usually from blood, a serological test is still necessary to provide a more rapid method of diagnosis. The indirect fluorescent antibody test, using a Salmonella typhi Vi antigen and a FITC-conjugated rabbit anti-human polyvalent immunoglobulin, was evaluated for the diagnosis of typhoid fever. Serum specimens were collected from patients with febrile diseases on admission. Of the 32 patients with titers of 1:64 or more, 22 were confirmed to have typhoid fever by blood culture and 7 had fever of undetermined origin that was considered to be typhoid fever clinically. Three patients were diagnosed to have salmonellosis other than typhoid fever. Of the 121 patients with titers of 1:32 or less, 105 patients had non-typhoidal febrile disease, 15 patients had fever of undetermined origin, and one patient was confirmed to have typhoid fever by blood culture. When a Vi antibody titer of 1:64 or more was taken as serological evidence for the diagnosis of typhoid fever, the sensitivity and specificity were 95.7% and 97.2%, respectively. The incidence of positive test results following fever onset was 70.0% within 1 week of fever onset, 88.9% from 1 to 2 weeks, and 100% after 2 weeks. In conclusion, the Vi-indirect fluorescent antibody test(Vi-IFAT) can be employed as a useful serologic test in the diagnosis of typhoid fever.

Antigens, Bacterial↗
PubMed1989

Application of serologic diagnosis of tsutsugamushi disease (scrub typhus) in Korea where the disease was recently recognized to be endemic.

In Korea, tsutsugamushi disease is a recently recognized infection. It has become clear that it is more prevalent than leptospirosis or hemorrhagic fever with renal syndrome. Accurate diagnosis of the disease is necessary for the selection of effective antimicrobial agents which can prevent fatalities and shorten the course. For the diagnosis, various serologic tests are used. Sensitivity and specificity of a test depend on various factors. In this report, microbiological aspects of the infection were briefly described and the Weil-Felix, indirect immunofluorescence and indirect immunoperoxidase tests were compared for their applicability in routine use and usefulness in the diagnosis. Their interpretations were also briefly discussed.

Adolescent↗
PubMed1987

Antimicrobial susceptibility of bacteria isolated in 1985--with special reference to prevalence of methicillin-resistant staphylococcus aureus and activities of cefazolin, cefotaxime and piperacillin.

Antimicrobial susceptibility of nine species and one group of bacteria isolated from patients at the hospitals of Seoul National University, Severance, Hanyang University, and Kyungpuk University were tested by agar dilution method. S. aureus was most susceptible to cefazolin, methicillin and cotrimoxazole, and enterococci to ampicillin. Isolates of Enterobacteriaceae were most frequently susceptible to aminoglycosides and cefotaxime. Cefazolin susceptibility was markedly different from species to species. Aminoglycosides and piperacillin were more active than others against P. aeruginosa, and amikachin against A. anitratus. A large proportion of strains of several different species were conditionally susceptible to either tetracycline, ampicillin, cefazolin or cotrimoxazole suggesting the usefulness of these drugs for treatment of urinary tract infection. Activity of cefotaxime was highest against E. coli, and K. pneumoniae, while lowest against A. anitratus and P. aeruginosa. Decrease in the proportion of susceptible isolate was noted in E. coli and K. pneumoniae to cefazolin, K. pneumoniae, E. cloacae and S. marcescens to cotrimoxazole, and P. aeruginosa to tobramycin and gentamicin.

Anti-Bacterial Agents↗
PubMed1985

Comparison of aminoglycoside resistance patterns in Japan, Formosa, and Korea, Chile, and the United States.

The resistance mechanisms of more than 2,000 aminoglycoside-resistant gram-negative aerobic bacteria were estimated by a method that assigned a biochemical mechanism based on susceptibility to selected aminoglycosides. Strains from hospitals in Japan, Formosa, and Korea (the Far East) were compared with strains from Chile and the United States. Of the strains from Chile, 90% had an aminoglycoside resistance pattern indicative of the 3-N-acetyltransferase [AAC(3)-V] enzyme. Of the strains from the Far East, 78% had susceptibility patterns suggesting the presence of AAC(6') enzymes. In contrast, strains from the United States had a wider variety of resistance mechanisms including 2''-O-adenylyltidyltransferase [ANT(2'')], AAC(3), AAC(6'), and AAC(2'). Reflecting these differences in resistance patterns, the frequencies of resistance to gentamicin, tobramycin, dibekacin, and amikacin in strains from the United States were different from those in strains from the Far East. These differences seem to be correlated with different aminoglycoside usage in the two regions. In the United States, where gentamicin was the most widely used aminoglycoside, 92% of the strains were resistant to gentamicin, 81% were resistant to dibekacin, and 8.8% were resistant to amikacin. In the Far East, dibekacin and kanamycin were widely used in the past and more recently amikacin has been frequently used. Of the strains from this region, 99% were resistant to dibekacin, 85% were resistant to gentamicin, and 35% were resistant to amikacin.

Aminoglycosides↗