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B Y Yoon

Publications and source records attributed to B Y Yoon.

4 recordsLinked to original sources
PubMed1997

Evidence for the essential histidine residues in geranylgeranyl transferase type I from bovine testis.

Geranylgeranyl transferase was purified 30,000-fold by sequential use of 30-50% ammonium sulfate fractionation, Q-Sepharose anion exchange chromatography, Phenyl Superose hydrophobic interaction chromatography, Sephacryl S-300 gel filtration chromatography, and peptide (YREKKFFCAIL) affinity chromatography. Geranylgeranyl transferase, when incubated with diethyl pyrocarbonate (DEPC), a histidine-specific reagent, shows time-dependent inactivation, and the activity is restored by the addition of neutral hydroxylamine. The inactivation follows pseudo-first order kinetics with a second order rate constant of 0.319 M-1min-1. The overall results thus provide evidence that a histidine residue in the active site is involved in the catalytic mechanism of the geranylgeranyl transferase reaction.

Alkyl and Aryl Transferases↗
PubMedDate not supplied

The prevalence of atopy and atopic diseases in Behçet's disease.

OBJECTIVE: The prevalence of Th-2 cell-mediated diseases, such as atopic diseases, has been noted to be low in Th-1 cell-mediated diseases. This study was undertaken to assess the prevalence of atopy and atopic diseases in Behçet's disease (BD), a Th-1 cell-mediated disease, and to investigate the clinical association between the atopy and the development of severe manifestations in BD. METHODS: We examined 70 consecutive BD patients and 113 controls without BD or other inflammatory rheumatic diseases. The cumulative history of severe manifestations in BD patients was investigated during the disease course. A skin prick test was performed in all the subjects, and atopy was defined as present when the size of one or more allergen-induced wheals was equal to or larger than that caused by histamine. Atopic diseases were defined as present when there were relevant responses for atopic diseases on the questionnaires in the subjects with atopy. In addition, serum IgE levels and peripheral blood eosinophil counts were measured. RESULTS: The prevalence of atopy and atopic diseases was significantly lower in BD patients than in controls. Other atopy parameters, such as serum IgE levels and peripheral blood eosinophil counts, were also significantly lower in BD patients when compared with controls. However, atopy, serum IgE levels, and peripheral blood eosinophil counts did not differ significantly between BD patients with and without severe manifestations. CONCLUSION: The prevalence of Th-2 cell-mediated conditions, such as atopy and atopic diseases, appeared to be lower in BD, a Th-1 cell-mediated disease. In addition, a Th-1 and Th-2 balance may not influence the development of severe manifestations in BD.

Adult↗
PubMedDate not supplied

Validation of the classification criteria commonly used in Korea and a modified set of preliminary criteria for Behçet's disease: a multi-center study.

OBJECTIVE: Recently we have proposed a modified set of criteria to settle the questions raised regarding the International Study Group (ISG) criteria for Behçet's disease (BD). The aim of the present study was to validate the two pre-existing criteria sets commonly used in Korea, the ISG criteria and the criteria of the Behçet's Disease Research Committee of Japan (Japanese criteria), as well as the proposed modified criteria. METHODS: The study population included 155 consecutive patients with BD and 170 controls with non-Behçet's rheumatic diseases. Detailed data for all of the subjects were recorded prospectively by the participating physicians on a standard form that listed the clinical features of BD. The sensitivity, specificity, and accuracy of each set of the criteria were measured. RESULTS: Of the three criteria sets employed, the modified criteria were the most accurate, with an accuracy of 96.3%. The ISG criteria often failed to classify the following patients with BD: patients with only oral and genital ulcerations, certain patients with intestinal ulcerations, patients who did not manifest oral ulcerations, and patients with acute disease but fewer than three recurrent oral ulceration relapses in a 1-year period. The Japanese criteria also failed to categorize the following patients with BD: patients with oral and genital ulcerations, and patients with oral ulcerations, skin lesions, and a positive pathergy reaction. In addition, the Japanese criteria misclassified some of the control subjects with non-Behçet's uveitis as having BD. CONCLUSIONS: The results of this study suggest that there are some points that need to be reconsidered in the clinical application of the two pre-existing sets of criteria. Although the modified criteria were the most accurate, further validation studies will be required in other ethnic populations.

Adult↗