Effects of Pre-analytical Variables on Cell-free DNA Extraction for Liquid Biopsy

BACKGROUND: Extraction of cell-free DNA (cfDNA) is a key step for determining the quality of cfDNA-related molecular diagnostics. We evaluated the effect of sample containers and sample storage conditions on cfDNA extraction. METHODS: The cfDNA extraction using the MagMAX Cell-Free DNA Isolation Kit from five healthy controls and five lung cancer patients was evaluated according to the type of sample container and storage conditions: K2-EDTA container, <1, 6, 24, and 48 hr storage at 4℃ after immediate plasma separation; and Cell-Free DNA BCT container, <1, 3, 7, and 14 days stored at room temperature. Mutation analysis of EGFR exons 18–21 was performed. To assess the effect of a delay in centrifugation, EDTA whole blood samples from five healthy individuals were stored at 4℃ for 6, 12, and 24 hr before plasma separation. RESULTS: There was no significant difference in the amount and nucleic acid size of cfDNA in both controls and patients with cancer when EDTA plasma was stored at 4℃ up to 48 hr. The amount and size of cfDNA in the BCT container were not different up to 7 days; however, the 14-day sample showed an increase in cfDNA concentration due to genomic DNA contamination. EGFR mutations were detected on EDTA containers up to 48 hr and with BCT containers up to 14 days. When EDTA whole blood was stored at 4℃ and plasma separation was delayed, the cfDNA concentration increased from 24 hr. CONCLUSIONS: The cfDNA extraction was affected by the sample containers and storage conditions.

A case of left atrial myxoma presenting as interstitial pulmonary edema / 대한내과학회지

Primary neoplasm of the heart is rare. Benign tumors, the majority of which are myxomas, comprise up to 50% of cardiac neoplasms. Although cardiac myxoma is a source of emboli to the central nervous system and elsewhere in the vascular tree, its clinical signs and symptoms may be nonspecific. These nonspecific systemic symptoms and minor embolic phenomena may be overlooked in patients without a previous history of cardiac problems. Thus, we need to recognize the signs of myxoma and begin treatment immediately. We encountered a case of left atrial myxoma, presenting as pulmonary interstitial edema of unknown cause, in a 50-year-old female patient. Excision of a mass located on the left atrium was scheduled but she developed a cerebral embolism that led to her death.

Hepatopulmonary Syndrome Induced by Common Bile Duct Ligation in a Rabbit Model: Correlation between Pulmonary Vascular Dilatation on Thin-Section CT and Angiography and Serum Nitrite Concentration or Endothelial Nitric Oxide Synthase (eNOS) 1 Expression

OBJECTIVE: To investigate the correlation between radiologic vascular dilatation and serum nitrite concentration and eNOS expression in the endothelial cell and pneumocyte in a rabbit model of hepatopulmonary syndrome induced by common bile duct ligation (CBDL). MATERIALS AND METHODS: Thin-section CT scans of the lung and pulmonary angiography were obtained 3 weeks after CBDL (n=6), or a sham operation (n=4), and intrapulmonary vasodilatation was assessed. The diameter and tortuosity of peripheral vessels in the right lower lobe by thin-section CT and angiography at the same level of the right lower lobe in all subjects were correlated to serum nitrite concentration and eNOS (endothelial nitric oxide synthase) expression as determined by immunostaining. RESULTS: The diameters of pulmonary vessels on thin-section CT were well correlated with nitrite concentrations in serum (r = 0.92, p < 0.001). Dilated pulmonary vessels were significantly correlated with an increased eNOS expression (r = 0.94, p < 0.0001), and the severity of pulmonary vessel tortuosity was found to be well correlated with serum nitrite concentration (r = 0.90, p < 0.001). CONCLUSION: The peripheral pulmonary vasculature in hepatopulmonary syndrome induced by CBLD was dilated on thin-section CT and on angiographs. Our findings suggest that peripheral pulmonary vascular dilatations are correlated with serum nitrite concentrations and pulmonary eNOS expression.

Development of Systemic Lupus Erythematosus after Total Resection of a Thymoma for Myasthenia Gravis / 대한내과학회지

Systemic lupus erythematosus and myasthenia gravis are autoimmune disorders in which genetic, environmental and hormonal as well as immunological factors have been implicated. We experienced a case of 24 year-old female patient developed SLE(anemia, leukopenia, facial malar rash, high titers of anti-DNA and anti-nuclear antibody) 3 years following successful therapeutic thymectomy for myas thenia gravis. A review of the world-wide literature revealed 8.3% to 24.3% association between myasthenia gravis and SLE. However there has been no controlled epidemiological study to prove a real association between these two disease. The differential diagnosis of fatigue and fever in patient with SLE should always include the possibility of myasthenia gravis.