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1.
Yonsei Medical Journal ; : 618-624, 2023.
Article in English | WPRIM | ID: wpr-1003240

ABSTRACT

Purpose@#Tinnitus is one of the most common health conditions worldwide. Although various methods of treatment have been used, the condition is still difficult to manage or cure. This study aimed to evaluate the therapeutic effects of transcutaneous trigeminal electrical stimulation (TTES) combined with notched sound therapy (NST) on patients with tinnitus. @*Materials and Methods@#A clinical trial was conducted prospectively from September 2020 to September 2021 at a single center in South Korea. In total, 14 patients took part in this trial. Periodic visits and tele-monitoring were used to assess treatment compliance and collect data, including electroencephalography (EEG), photoplethysmography (PPG), tinnitus handicap inventory (THI), tinnitus magnitude index, Beck Depression Inventory (BDI), Pittsburgh Sleep Quality Index (PSQI), and 36-item short-form survey (SF-36) results. @*Results@#Changes after intervention were analyzed with paired t-test. This study showed that alpha waves in the left hemisphere measured by EEG (p=0.024), autonomic nervous system balance (p=0.007), and stress level (p=0.022) measured by PPG significantly changed after intervention. Also, THI scores especially emotional symptoms (p=0.029) and catastrophic symptoms (p=0.043) decreased after treatment. The SF-36 score, both mental component summary and physical component summary score (each p<0.001), increased significantly, whereas the PSQI score (p<0.001) and BDI score (p<0.001) decreased after TTES and NST. @*Conclusion@#Based on the results of our study, we could confirm that TTES combined with NST can significantly improve tinnitus, catastrophic symptoms, and the overall quality of life of patients.

2.
Tissue Engineering and Regenerative Medicine ; (6): 695-704, 2023.
Article in English | WPRIM | ID: wpr-1003132

ABSTRACT

BACKGROUND@#Human endothelial progenitor cells (EPCs) were first identified in the peripheral blood and later in the cord blood and bone marrow (BM) with different vascularization capacity and different surface marker profiles. However, their identity and functional roles in neovascularization have not been clearly demonstrated in vivo and in vitro. @*METHODS@#Characterization of BM-EPC like cells were performed by fluorescence-activated cell sorting, immunofluorescence staining, enzyme-linked immunosorbent assay, Matrigel tube formation assay, and western blot analysis. @*RESULTS@#BM-EPC like cells were identified by selective adhesion to fibronectin and collagen from BM mononuclear cells, which generate fast-growing colonies with spindle morphology, express surface markers of CD105, vWF, UEA-I lectin binding, secrete HGF, VEGF, TGF-beta1 but can be distinguished from circulating EPC and endothelial cells by no expression of surface markers such as CD31, CD309, CD45, and CD34. These BM-EPC like cells shared many cell surface markers of BM-mesenchymal stem cells (MSC) but also can be distinguished by their vasculogenic property and other unique surface markers. Furthermore, the vasculogenic capacity of BM-EPC like cells were enhanced by co-culture of BMMSC or PDGF-BB priming. PDGF-BB stimulated cell migration, proliferation, and secretion of laminin b-1, which was proposed as one of the mechanisms involved in the better vascularization of BM-EPC like cells. @*CONCLUSION@#PDGF-BB priming may be applied to improve the potency and function of BM-EPC like cells as vasculogenic cell therapy for the ischemic vascular repair.

3.
The Korean Journal of Orthodontics ; : 393-401, 2023.
Article in English | WPRIM | ID: wpr-1003091

ABSTRACT

Objective@#To investigate the long-term effects of 4-hexylresorcinol (4HR) on facial skeletal growth in growing male rats, with a focus on diabetic animal models. Methods: Forty male rats were used. Of them, type 1 diabetes mellitus was induced in 20 animals by administering 40 mg/kg streptozotocin (STZ), and they were assigned to either the STZ or 4HR-injected group (STZ/4HR group).The remaining 20 healthy rats were divided into control and 4HR groups. We administered 4HR subcutaneously at a weekly dose of 10 mg/kg until the rats were euthanized. At 16 weeks of age, whole blood was collected, and microcomputed tomography of the skull and femur was performed. Results: All craniofacial linear measurements were smaller in the STZ group than in the control group. The mandibular molar width was significantly smaller in the 4HR group than in the control group (P = 0.031) but larger in the STZ/4HR group than in the STZ group (P = 0.011). Among the diabetic animals, the STZ/4HR group exhibited significantly greater cortical bone thickness, bone mineral density, and bone volume than the STZ group. Serum testosterone levels were also significantly higher in the STZ/4HR group than in the STZ group. @*Conclusions@#4HR administration may have divergent effects on mandibular growth and bone mass in healthy and diabetic rats. In the context of diabetes, 4HR appears to have beneficial effects, potentially through the modulation of mitochondrial respiration.

4.
The Korean Journal of Internal Medicine ; : 734-746, 2023.
Article in English | WPRIM | ID: wpr-1003070

ABSTRACT

Background/Aims@#We performed a prospective study to determine the efficacy and safety of rituximab including chemotherapy in CD20-positive acute lymphoblastic leukemia (ALL). @*Methods@#Patients with newly diagnosed ALL, aged ≥ 15 years, were eligible for the study if their leukemic blast cells in bone marrow expressed CD20 ≥ 20% at the time of diagnosis. Patients received multiagent chemotherapy with rituximab. After achieving complete remission (CR), patients received five cycles of consolidation with concomitant rituximab. Rituximab was administered monthly from day 90 of transplantation for patients who received allogeneic hematopoietic cell transplantation. @*Results@#In patients with Philadelphia (Ph)-negative ALL, 39 of 41 achieved CR (95.1%), the 2- and 4-year relapse-free survival (RFS) rates were 50.4% and 35.7%, and the 2- and 4-year overall survival (OS) rates were 51.5% and 43.2%, respectively. In the group with Ph-positive ALL, all 32 patients achieved CR, the 2- and 4-year RFS rates were 60.7% and 52.1%, and the 2- and 4-year OS rates were 73.3% and 52.3%, respectively. In the Ph-negative ALL group, patients with higher CD20 positivity experienced more favorable RFS (p < 0.001) and OS (p = 0.06) than those with lower CD20 positivity. Patients who received ≥ 2 cycles of rituximab after transplantation had significantly improved RFS (hazard ratio [HR], 0.31; p = 0.049) and OS (HR, 0.29; p = 0.021) compared with those who received < 2 cycles. @*Conclusions@#The addition of rituximab to conventional chemotherapy for CD20-positive ALL is effective and tolerable (Clinicaltrials. gov NCT01429610).

5.
The Korean Journal of Internal Medicine ; : 651-660, 2023.
Article in English | WPRIM | ID: wpr-1003065

ABSTRACT

Background/Aims@#Recently, 1 L of polyethylene glycol (PEG) plus ascorbic acid (Asc) has been introduced in Korea as a colonoscopy preparation agent. Data on its efficacy and safety in older adults have been limited. We aimed to evaluate the safety and efficacy of 1 L PEG/Asc in older adults by comparing it with oral sulfate solution (OSS). @*Methods@#A prospective multicenter randomized study was conducted with subjects aged ≥ 65 years who underwent colonoscopy. The participants were randomized to receive 1 L PEG/Asc or OSS. The primary endpoint was successful bowel preparation, defined as total Boston Bowel Preparation Scale ≥ 6, and ≥ 2 at each segment. Patient satisfaction, adverse events, and renal function changes were compared between the groups. @*Results@#Among the 106 patients, 104 were finally included in the analysis. Overall, successful bowel preparation was achieved in 96.2% of both 1 L PEG/Asc and OSS groups. The satisfaction scores for taste, total amount ingested, overall feeling, and willingness to repeat the same regimen were not significantly different between the groups. Adverse events of moderate or higher severity occurred in 16 and 10 cases in the 1 L PEG/Asc and OSS group, respectively. There were no significant changes in electrolyte levels or renal function from baseline. @*Conclusions@#The successful bowel preparation rate was > 90% in both groups without severe adverse effects and significant changes in renal function. As a new low-dose preparation regimen for colonoscopy in older adults, 1 L PEG/Asc, is as effective and safe as OSS.

6.
The Korean Journal of Internal Medicine ; : 641-650, 2023.
Article in English | WPRIM | ID: wpr-1003057

ABSTRACT

Gout is the most common form of arthritis, with the prevalence increasing worldwide. The present treatment guidelines provide recommendations for the appropriate treatment of acute gout, management during the inter-critical period, and prevention of chronic complications. The guidelines were developed based on evidence-based medicine and draft recommendations finalized after expert consensus. These guidelines are designed to provide clinicians with clinical evidence to enable efficient treatment of gout.

7.
The Korean Journal of Helicobacter and Upper Gastrointestinal Research ; : 240-246, 2023.
Article in Korean | WPRIM | ID: wpr-1003000

ABSTRACT

Obesity is a global health concern associated with a wide range of diseases, including diabetes, metabolic syndrome, fatty liver, and cardiovascular conditions. Recent studies highlight the significant role of gut microbiota in obesity. Research indicates notable changes in the composition and diversity of gut microbiota in individuals diagnosed with obesity. The gut microbiota participate in energy metabolism, lipid synthesis, and regulation of inflammation and therefore play a key role in the pathogenesis of obesity. Therapeutic approaches based on the use of probiotics, prebiotics, Akkermansia muciniphila, and fecal microbiota transplantation have shown promise in animal studies as useful strategies against obesity and metabolic syndrome. However, further research is warranted to conclusively establish the specific strains, dosages, and mechanisms underlying the effectiveness of these novel strategies against obesity in humans.

8.
The Korean Journal of Gastroenterology ; : 213-223, 2023.
Article in English | WPRIM | ID: wpr-1002968

ABSTRACT

Portal hypertension is a clinical syndrome defined by an increased portal venous pressure. The most frequent cause of portal hypertension is liver cirrhosis, and many of the complications of cirrhosis, such as ascites and gastroesophageal variceal bleeding, are related to portal hypertension. Portal hypertension is a pathological condition caused by the accumulation of blood flow in the portal system. This blood flow retention reduces the effective circulation volume. To compensate for these changes, neurotransmitter hormone changes and metabolic abnormalities occur, which cause complications in organs other than the liver. A hepatic hydrothorax is fluid accumulation in the pleural space resulting from increased portal pressure. Hepatopulmonary syndrome and portopulmonary hypertension are the pulmonary complications in cirrhosis by deforming the vascular structure. Symptoms, such as dyspnea and hypoxia, affect the survival and the quality of life of patients. These lung complications are usually underestimated in the management of cirrhosis. This review briefly introduces the type of lung complications of cirrhosis.

9.
The Korean Journal of Gastroenterology ; : 10-17, 2023.
Article in English | WPRIM | ID: wpr-1002939

ABSTRACT

Background/Aims@#Increasing resistance to clarithromycin (CAM) of Helicobacter pylori (H. pylori) is one of the main causes of recent decrease in eradication rate of standard triple therapy. The aim of this study was to evaluate the usefulness of 7-day tailored therapy based on the existence of CAM resistance. @*Methods@#From January 2017 to May 2022, a total of 481 consecutive patients with H. pylori infection were recruited in Daegu Catholic University Medical Center. Treatment regimen was selected based on the result of CAM resistance test. Patients with CAM resistance (R group) were treated with bismuth-based quadruple therapy for 7 days. Patients without CAM resistance (S group) were treated with standard triple therapy for 7 days. @*Results@#The overall H. pylori eradication rate was 89.4% (379 of 424) by per-protocol (PP) analysis. Patients with CAM resistance mutation included 166 patients (34.5%). The eradication rates of each group were 88.8% (135 of 152) and 89.7% (244 of 272) by PP analysis, for R and S group respectively. By intention-to-treat (ITT) analysis, the eradication rates were 81.3% (135 of 166) and 77.5% (244 of 315) for R and S group. CAM resistance was identified with a dual-priming oligonucleotide-based multiplex PCR. @*Conclusions@#In spite of this high CAM resistance (34.5%), the eradication rate of 7-day tailored therapy based on the existence of CAM resistance was 89.4%. The 7-day tailored therapy based on CAM resistance could be an acceptable treatment selection strategy for H. pylori eradication.

10.
The Korean Journal of Gastroenterology ; : 63-72, 2023.
Article in English | WPRIM | ID: wpr-1002930

ABSTRACT

The prevalence of obesity has increased significantly worldwide, and this trend is likely to continue in the coming years. There is substantial evidence that obesity plays a crucial role in the development of colorectal cancer. Epidemiological data have consistently demonstrated a correlation between obesity and colorectal cancer. Insulin resistance, hyperinsulinemia, chronic inflammation, altered levels of growth factors, adipocytokines, and various hormones are plausible biological mechanisms. In addition, obesity has been shown to have an impact on recurrence, treatment success, and overall survival. There are some reports, although the evidence is not conclusive, that weight loss and lifestyle changes such as dietary modification and physical activity can reduce the risk of colorectal cancer. The understanding that obesity is a potentially modifiable risk factor that can affect the incidence and prognosis of colorectal cancer is crucial knowledge that can have an impact on the prevention and treatment of the condition.

11.
The Journal of Korean Academy of Prosthodontics ; : 215-226, 2023.
Article in English | WPRIM | ID: wpr-1002886

ABSTRACT

Severe wear of the anterior teeth facilitates the loss of anterior guidance, which protects the posterior teeth from wear during excursive movement. Additionally, when treating patients with collapsed occlusion due to multiple tooth loss and tooth wear, it is important to determine the presence of vertical dimension loss through accurate clinical and radiographic examinations and diagnostic wax-up. The patient of this case is a 44-year-old female patient who complained of overall tooth wear and loss of posterior teeth due to bruxism and clenching habits, visited the hospital with the address of restoring masticatory function and improving aesthetic appearance through prosthetic treatment. Through model analysis and diagnostic wax-up, an increase in vertical dimension was determined, and full mouth restoration with fixed prostheses was planned. The degree of adaptation to the vertical dimension was confirmed step by step using an occlusal splint designed with CAD (Computer aided design) software and 3-D (3-Dimensional) printed, and then restored with provisional restoration and after a 4-month adaptation period, the entire dentition was restored with metal ceramic crowns and implants. Through this procedure, satisfactory treatment results were obtained in terms of function and aesthetics.

12.
Soonchunhyang Medical Science ; : 29-33, 2023.
Article in Korean | WPRIM | ID: wpr-1002836

ABSTRACT

Castleman’s disease is a rare non-neoplastic lymphoproliferative disorder of unknown origin. It is classified into unicentric or multicentric based on its anatomical distribution. Multicentric Castleman’s disease can be subdivided according to the presence of human herpesvirus-8 (HHV-8) infection. Castleman’s disease has a rare incidence, and HHV-8-positive multicentric Castleman’s disease is even rarer. There are several types of natural course for this disease, and the rapidly progressing type can lead to death within a few weeks, emphasizing the need for prompt diagnosis and treatment. We report a recent case from Korea, presenting with multiple lymphadenopathies, confirmed as HHV-8-positive multicentric Castleman’s disease through biopsy, and achieving complete response with rituximab monotherapy.

13.
Osong Public Health and Research Perspectives ; (6): 89-99, 2023.
Article in English | WPRIM | ID: wpr-1002608

ABSTRACT

Objectives@#This study aimed to classify coronavirus disease 2019 (COVID-19)-related deaths according to whether COVID-19 was listed as the cause of death, and to investigate thedifferences in demographic characteristics and risk factors for COVID-19 death classifications. @*Methods@#A total of 5,625 deaths in South Korea among patients with confirmed COVID-19 from January 20, 2020 to December 31, 2021 were selected. Excluding false reports and unnatural deaths, 5,597 deaths were analyzed. Based on death report data, deaths were classified according to whether the cause of death was listed as COVID-19 (CD) or not (NCD). The epidemiological characteristics and causes of deaths were investigated using descriptive, univariate, and multivariate statistical analyses. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to analyze the risk factors. @*Results@#The case fatality ratio was 0.89% and increased with age. Additionally, 96.4% of the subjects had an underlying disease, and 53.4% died in winter. The proportion of NCDs was 9.3%, of whom 19.1% died at home and 39.0% were confirmed to have COVID-19 after death. Malignant neoplasms (102/416 vs. 637/4,442; OR, 1.71; 95% CI, 1.36−2.16; p < 0.001) were significantly associated with NCD. @*Conclusion@#This is the first study to analyze risk factors by cause of death using COVID-19death report data in South Korea. These results are expected to be used as evidence forestablishing a death monitoring system that can collect timely information in a new infectiousdisease pandemic.

14.
Nutrition Research and Practice ; : 1028-1041, 2023.
Article in English | WPRIM | ID: wpr-1002590

ABSTRACT

BACKGROUND/OBJECTIVES@#This study aimed to analyze the potential of school meals in South Korea as a sustainable tool to reduce carbon emissions by focusing on animal- vs.plant-based protein foods.MATERIALS/METHODS: By using a stratified proportional allocation method, 536 out of the 11,082 schools nationwide were selected including 21 kindergartens, 287 elementary-, 120 middle- and 108 high schools. A total of 2,680 meals served for 5 consecutive days (June 21–25, 2021) were collected. We analyzed the average serving amounts of protein foods (animal- vs. plant-based) per meal and then, calculated the estimated average amounts of carbon emission equivalents per meal by applying the conversion coefficients. The t-test and analysis of variance were used for statistical analyses (α = 0.05). @*RESULTS@#The average serving amount of animal-based protein foods per meal was 12.5 g, which was approximately 3 times higher than that of plant-based ones (3.8 g) (P < 0.001); the Meat-group had the highest average amount of 17.0 g, followed by Egg-group (9.6 g), Fishgroup (7.6 g), and Beans-and-Nuts-group (3.8 g) (P < 0.05). Specifically, pork (25.1 g) was ranked first, followed by poultry (19.6 g), processed meat products (18.0 g). The estimated average amount of carbon emission equivalents of animal-based protein foods per meal was 80.1 g CO 2 e, which was approximately 31 times higher than that of plant-based ones (2.6 g CO 2 e) (P < 0.001); the Meat-group had the highest average amount of 120.3 g CO 2 e, followed by Fish-group (44.5 g CO 2 e), Egg-group (25.9 g CO 2 e), and Beans-and-Nuts-group (2.6 g CO 2 e) (P < 0.05). Specifically, processed meat products (270.8 g CO 2 e) were ranked first, followed by pork (91.7 g CO 2 e), and processed fish products (86.6 g CO 2 e). @*CONCLUSIONS@#The results implied that school meals with plant-based alternatives could be a sustainable tool to improve carbon footprint.

15.
Nutrition Research and Practice ; : 641-659, 2023.
Article in English | WPRIM | ID: wpr-1002586

ABSTRACT

BACKGROUND/OBJECTIVES@#The skin is the outermost organ of the human body and plays a protective role against external environmental damages, such as sunlight and pollution, which affect anti-oxidant defenses and skin inflammation, resulting in erythema or skin reddening, immunosuppression, and epidermal DNA damage.MATERIALS/METHODS: The present study aimed to investigate the potential protective effects of red orange complex H extract (ROC) against ultraviolet (UV)-induced skin photoaging in Skh:HR-2 mice. ROC was orally administered at doses of 20, 40, and 80 mg/ kg/day for 13 weeks, along with UV irradiation of the mice for 10 weeks. @*RESULTS@#ROC improved UV-induced skin barrier parameters, including erythema, melanin production, transepidermal water loss, elasticity, and wrinkle formation. Notably, ROC inhibited the mRNA expression of pro-inflammatory cytokines (interleukin 6 and tumor necrosis factor α) and melanogenesis. In addition, ROC recovered the UV-induced decrease in the hyaluronic acid and collagen levels by enhancing genes expression. Furthermore, ROC significantly downregulated the protein and mRNA expression of matrix metalloproteinases responsible for collagen degradation. These protective effects of ROC against photoaging are associated with the suppression of UV-induced phosphorylation of c-Jun NH2-terminal kinase and activator protein 1 activation. @*CONCLUSIONS@#Altogether, our findings suggest that the oral administration of ROC exerts potential protective activities against photoaging in UV-irradiated hairless mice.

16.
Neonatal Medicine ; : 89-95, 2023.
Article in English | WPRIM | ID: wpr-1002553

ABSTRACT

Human microbiome refers to the genetic material of approximately 1013 microorganisms present in the human body. These microbiomes interact significantly with the physiological, metabolic, and immune systems, particularly during pregnancy. Microbiome dysbiosis in pregnant women and their fetuses is associated with obstetric complications and poor neonatal outcomes. Oral and gut microbiomes can influence the placenta, uterus, and fetus via hematogenous translocation. Through ascending translocation, vaginal microbiota can directly affect the uterine environment. Current research focuses on the presence of the placental microbiome, which is characterized by low biomass. However, more well-controlled studies are required to specifically address the contamination issues. Use of antibiotics during pregnancy and the mode of delivery, specifically cesarean section, have been linked to the establishment of the neonatal gut microbiome. Probiotic supplementation may be beneficial during pregnancy, particularly for women receiving antibiotic treatment.

17.
Laboratory Animal Research ; : 49-57, 2023.
Article in English | WPRIM | ID: wpr-1002508

ABSTRACT

Background@#Orthotopic liver transplantation is the only option for patients with end-stage liver disease and hepatocellular carcinoma. Post-transplant immunosuppressive therapy is important to prevent graft failure. We investigated the effectiveness of tacrolimus (FK506) and their mechanisms for liver transplant immune tolerance in an outbred rat LT model. @*Results@#To investigate the therapeutic effect of the FK506 on outbred rat LT model, FK506 and postoperative therapy were administered subcutaneously once or twice daily to transplanted rats. Histopathological and immunohistochemical analyses were conducted for all groups. The regulation of inflammatory cytokine signaling in the spleen was analyzed by flow cytometry. FK506 attenuated allograft rejection and increased survival in rat orthotopic liver transplantation models. The FK506-treated group had reduced serum levels of alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase. Furthermore, FK506 decreased the expression of inflammatory cytokines and the activation of pathogenic Th1 and Th17 cells in the liver. @*Conclusions@#Taken together, we revealed that FK506 ameliorated strong allograft rejection in outbred liver transplantation model by anti-inflammatory effect and inhibitory peroperty of pathogenic T cells.

18.
Kosin Medical Journal ; : 219-223, 2023.
Article in English | WPRIM | ID: wpr-1002494

ABSTRACT

The coronavirus disease 2019 (COVID-19) has been a major public health emergency worldwide. Vaccines were rapidly developed and approved to prevent the spread of viral infection. However, various side effects of the COVID-19 messenger RNA (mRNA) vaccines have been reported after their commercialization. A 24-year-old man visited our emergency department with polyuria and polydipsia that occurred after he received a COVID-19 mRNA vaccine 10 days beforehand. The initial laboratory findings showed very low urine osmolality with hyperosmolar hypernatremia. Based on these findings, diabetes insipidus was suspected, and sella magnetic resonance imaging showed an enlarged pituitary gland and the absence of posterior pituitary higher intensity. After 12 hours of using oral desmopressin acetate, urine volume decreased, and after 5 days of administration, serum electrolyte and serum osmolality improved. This case report of diabetes insipidus occurring after vaccination with the BNT162b2 mRNA COVID-19 vaccine is presented as a reminder that close monitoring is necessary for patients with polyuria and polydipsia after vaccination.

19.
Korean Journal of Veterinary Research ; : e21-2023.
Article in Korean | WPRIM | ID: wpr-1002475

ABSTRACT

The increasing prevalence of toxic substance-exposure in pets in South Korea endangers the health and safety of numerous companion animals, and has become a cause for concern. Notably, the annual incidence of forensic analysis in pets has increased by more than 150% in South Korea, mainly in populous regions such as Seoul, Incheon, and Gyeonggi. In response to this growing issue, veterinary forensic examinations were conducted on 549 dogs and cats from 2019 to 2022. This study revealed the presence of various toxic substances, including pesticides, insecticides, and drugs such as analgesics, anesthetics, antidepressants, and muscle relaxants, in pets. Among the 38 different toxins identified in pets, coumatetralyl, methomyl, terbufos, and buprofezin were the most frequently detected. In this study, toxic substances for pets were identified based on the “toxic agent list for humans,” developed by the National Forensic Services, because no list of toxic agents for animals currently exists and data regarding potentially toxic substances for dogs and cats is limited. This is one of the limitations of this study, and necessitates the establishment of a toxic agent list for animals. Continued monitoring and research is also recommended to reveal the incidence, causes, and solutions of toxicity in animals.

20.
Korean Journal of Veterinary Research ; : e23-2023.
Article in Korean | WPRIM | ID: wpr-1002473

ABSTRACT

This study was conducted to investigate tiamulin (TML) residues in the edible tissues of orally dosed broiler chickens and to re-establish the withdrawal time (WT). Thirty-six healthy Ross broiler chickens were administered 0.5 (TML-1) and 2.5 kg (TML-2) per ton feed, respectively, of the drug containing TML 78 g/kg for 10 days. Twenty-four tissue samples were collected from 6 chickens in each of the TML-1 and TML-2 groups on 0, 1, 3, and 5 days after drug administration, respectively. The residual concentrations of TML were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The correlation coefficient of the calibration curves was 0.9978 to 0.9998, and the limits of detection and the limits of quantification (LOQ) were in the range of 0.03 to 0.06, and 0.1 to 0.2 µg/kg, respectively. Recoveries ranged between 89.0% to 116.7%, and the coefficients of variation were less than 13.9%. After the drug administration, TML in the TML-1 and TML-2 groups was detected above the LOQ in 1 and 6 samples of liver, respectively, at day 0, and in 1 liver sample from both groups on day one. At 3 days after administration, TML was detected below the LOQ in all samples of TML-1 and TML-2. The calculated WT of TML in both TML-1 and TML-2 using the WT calculation program WT 1.4 was 0 days. In conclusion, the developed analytical method is suitable for detection, and the calculated WT of TML in poultry edible tissues is shorter than the current recommended WT of 7 days for TML in broiler chickens.

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