• 한국동물위생학회지
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• 제25권3호
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• pp.221-227
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• 2002

This study was carried out to confirm analytical method of residual macrolides in livestock products by LC/MS. 1. Macrolides were analyzed by LC/MS on XTerra C$\sub$18/ column with 0.1% TFA(trifluoroacetic acid)-methanol in a gradient mode as mobile phase, and that were identified by positive chemical ionization with selective ion monitoring at 50～1000 mass range. 2. Residual macrolides were extracted from tissue with acetonitrile, and the extract is purified with a Sep-pak C$\sub$18/ cartridge, and elute macrolides with 0.1M methanolic ammonium acetate. 3. The procedure confirms the presence of each macrolide at 50$\mu\textrm{g}$/kg in spiked sample.

• Natural Product Sciences
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• 제28권1호
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• pp.33-39
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• 2022

Eight lignans (1-8) and two macrolides (9-10) were isolated from the CHCl₃-soluble fraction of Houttuynia cordata Thumb (Saururaceae). Structures of isolates were elucidated by extensive spectroscopic methods. Fatty acid-derived macrolides (9-10) have rarely been reported from nature. All the isolates were tested for their inhibitory activities against NO production in RAW 264.7 cells stimulated by LPS. It was found that compounds 3 and 9 remarkably down-regulated LPS-induced NO production with IC₅₀ values, 5.4 and 40.3 μM, respectively, without cytotoxicity.

• Tuberculosis and Respiratory Diseases
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• 제45권3호
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• pp.546-552
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• 1998

연구배경: Macrolide란 구조식에 14-number macrocyclic lactone ring을 갖는 항생제를 총칭한다. 최근 개발된 clarythromycin, azythromycin, roxithromycin 등은 기존의 erythromycin에 비하여 소화관 흡수가 용이하고, 반감기가 길며, 위장관 부작용은 덜하면서 몇몇 세균속에 대해서는 더욱 강력한 항균 효과가 있다고 알려져 있다. Erythromycin은 간장의 cytochrome P-450 효소계에 의해 불활성화 되기 때문에, 특히 호흡기 질환 환자에서 사용되는 theophylline의 혈중농도를 증가시켜 theophylline toxicity를 초래할 수 있다고 알려져 있다. 그러나 현재까지 new macrolide에 있어서는 이러한 효과에 대해서는 임상 연구가 미미한 실정이다. 방 법: 기관지 천식환자에서 erythromycin (1000mg/day), clarithromycin(500mg/day), azithromycin(500mg/day), roxithromycin(300mg/day) 등을 theophylline(400mg/day)과 경구 복합 투여하여, 투여전, 투여 후 1주 및 4주(azythyromycin은 1주)에 각각 theophylline 혈중 농도와 청소율을 측정하여 혈중 theophylline 농도 및 청소율에 대한 erythromycin과 new macrolides 항생제의 영향을 평가하고자 하였다. 결 과: Erythromycin과 roxithromycin 투여군에서는 투여 1주 후부터 유의한 theophylline 혈중농도의 상승을 보였으며 특히, erythromycin 투여군에서는 2예에서 병합 투여를 중지하였다. 이러한 소견은 theophylline 청소율에서도 유사하였으나 1주 및 4주간에는 유의한 상승소견을 보이지 않았다. Clarithromycin, azithromycin 투여군에서는 병합 투여중 유의한 혈중 농도의 상승이나 청소율의 감소 소견은 관찰되지 않았다. 결 론: 이상의 결과로 erythromycin 혹은 roxithromycin 투여 환자에 대하여 theophylline을 동시에 복합 투여하는 경우 혈중 theophylline 농도가 예상보다 증가될 수 있으므로 적절한 주기적 관리가 요할 것으로 사료된다.

• Clinical and Experimental Pediatrics
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• 제63권12호
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• pp.469-476
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• 2020

The major pathogens that cause atypical pneumonia are Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Legionella pneumophila. Community-acquired pneumonia (CAP) caused by M. pneumoniae or C. pneumoniae is common in children and presents as a relatively mild and self-limiting disease. CAP due to L. pneumophila is very rare in children and progresses rapidly, with fatal outcomes if not treated early. M. pneumoniae, C. pneumoniae, and L. pneumophila have no cell walls; therefore, they do not respond to β-lactam antibiotics. Accordingly, macrolides, tetracyclines, and fluoroquinolones are the treatments of choice for atypical pneumonia. Macrolides are the first-line antibiotics used in children because of their low minimum inhibitory concentrations and high safety. The incidence of pneumonia caused by macrolide-resistant M. pneumoniae that harbors point mutations has been increasing since 2000, particularly in Korea, Japan, and China. The marked increase in macrolide-resistant M. pneumoniae pneumonia (MRMP) is partly attributed to the excessive use of macrolides. MRMP does not always lead to clinical nonresponsiveness to macrolides. Furthermore, severe complicated MRMP responds to corticosteroids without requiring a change in antibiotic. This implies that the hyper-inflammatory status of the host can induce clinically refractory pneumonia regardless of mutation. Empirical macrolide therapy in children with mild to moderate CAP, particularly during periods without M. pneumoniae epidemics, may not provide additional benefits over β-lactam monotherapy and can increase the risk of MRMP.

• Clinical and Experimental Pediatrics
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• 제57권4호
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• pp.186-192
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• 2014

Purpose: The prevalence of macrolide-resistant Mycoplasma pneumoniae (MRMP) has increased worldwide. The aim of this study was to estimate the proportion of MRMP in a tertiary hospital in Korea, and to find potential laboratory markers that could be used to predict the efficacy of macrolides in children with MRMP pneumonia. Methods: A total of 95 patients with M. pneumoniae pneumonia were enrolled in this study. Detection of MRMP was based on the results of specific point mutations in domain V of the 23S rRNA gene. The medical records of these patients were reviewed retrospectively and the clinical course and laboratory data were compared. Results: The proportion of patients with MRMP was 51.6% and all MRMP isolates had the A2063G point mutation. The MRMP group had longer hospital stay and febrile period after initiation of macrolides. The levels of serum C-reactive protein (CRP) and interleukin-18 in nasopharyngeal aspirate were significantly higher in patients who did not respond to macrolide treatment. CRP was the only significant factor in predicting the efficacy of macrolides in patients with MRMP pneumonia. The area under the curve for CRP was 0.69 in receiver operating characteristic curve analysis, indicating reasonable discriminative power, and the optimal cutoff value was 40.7 mg/L. Conclusion: The proportion of patients with MRMP was high, suggesting that the prevalence of MRMP is rising rapidly in Korea. Serum CRP could be a useful marker for predicting the efficacy of macrolides and helping clinicians make better clinical decisions in children with MRMP pneumonia.

• The Korean Journal of Physiology and Pharmacology
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• 제11권6호
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• pp.259-262
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• 2007

Diffuse panbronchiolitis (DPB) is a pulmonary disease characterized by chronic inflammation of the bronchioles and chronic infiltration of inflammatory cells in the lungs. Macrolides are effective therapeutic agents for chronic respiratory tract diseases, such as DPB. However, the mechanisms by which macrolides modulate the immune responses in patients with DPB remain unclear. To understand clinical efficacy for the treatment of DPB by macrolides, the effects of erythromycin (EM) on the expression of pro-inflammatory cytokines such as interleukin-6 (IL-6) and interleukin-8 (IL-8) by human neutrophils were examined. Pre-treatment with EM significantly decreased the expression of IL-6 and IL-8 transcripts by lipopolysaccharide (LPS)-stimulated human neutrophils. EM also reversed the enhanced survival of human neutrophils by LPS. These data indicate that EM has achieved therapeutic effect for patients with DPB, in part, through decreasing the expression of pro-inflammatory cytokines and the survival of neutrophils.

• Clinical and Experimental Pediatrics
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• 제60권6호
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• pp.167-174
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• 2017

Mycoplasma pneumoniae pneumonia (MPP) is one of the most common forms of community-acquired pneumonia in children and adolescents. Outbreaks of MPP occur in 3- to 7-year cycles worldwide; recent epidemics in Korea occurred in 2006-2007, 2011, and 2015-2016. Although MPP is known to be a mild, self-limiting disease with a good response to macrolides, it can also progress into a severe and fulminant disease. Notably, since 2000, the prevalence of macrolide-resistant MPP has rapidly increased, especially in Asian countries, recently reaching up to 80%-90%. Macrolide-resistant Mycoplasma pneumoniae (MRMP) harbors a point mutation in domain V of 23S rRNA with substitutions mainly detected at positions 2063 and 2064 of the sequence. The excessive use of macrolides may contribute to these mutations. MRMP can lead to clinically refractory pneumonia, showing no clinical or radiological response to macrolides, and can progress to severe and complicated pneumonia. Refractory MPP is characterized by an excessive immune response against the pathogen as well as direct injury caused by an increasing bacterial load. A change of antibiotics is recommended to reduce the bacterial load. Tetracyclines or quinolones can be alternatives for treating MRMP. Otherwise, corticosteroid or intravenous immunoglobulin can be added to the treatment regimen as immunomodulators to downregulate an excessive host immune reaction and alleviate immune-mediated pulmonary injury. However, the exact starting time point, dose, or duration of immunomodulators has not been established. This review focuses on the mechanism of resistance acquisition and treatment options for MRMP pneumonia.

• Tuberculosis and Respiratory Diseases
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• 제78권4호
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• pp.401-407
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• 2015

Cryptogenic organizing pneumonia (COP) is an idiopathic interstitial pneumonia characterized by a subacute course and favorable prognosis with corticosteroids. However, some patients show resistance to steroids. Macrolides have been used with success in those patients showing resistance to steroids. A few reports showed treatment failure with macrolides in patients with COP who were resistant to steroids. In this report, we described two cases of COP who showed different responses to clarithromycin. One recovered completely, but the other gradually showed lung fibrosis with clarithromycin.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.37-40
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• 2002

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2002년도 제36회 학술심포지움
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• pp.32-36
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• 2002