Not All Flat-Panel C-Arms Are Created Equal: A Comparison of Three Major Manufacturers

Introduction: Flat-panel detector C-arms (FCs) are reported to reduce radiation exposure and improve image quality compared with conventional image intensifier C-arms (CCs). The purpose of this study was to compare radiation exposure and image quality between three commonly used FCs. Materials and Methods: A cadaver model was placed in the prone position to simulate percutaneous nephrolithotomy. We compared the following three FCs: OEC Elite CFD from GE HealthCare, Zenition 70 from Philips, and Ziehm Vision RFD from Ziehm Imaging. To measure the radiation dose, optically stimulated luminescence dosimeters (OSLDs) were utilized during five 300-second trials, conducted under three settings: automatic exposure control (AEC), AEC with low dose (LD), and LD with the lowest pulse rate (LDLP). Ten blinded urologists evaluated the image quality. Data were statistically analyzed using the analysis of variance (ANOVA) and Tukey's B post hoc tests. Results: In the AEC setting, the Philips C-arm demonstrated lower ventral OSLD exposure (42,446 mrad) compared with both the GE (51,076 mrad) and Ziehm (83,178 mrad; p < 0.001) C-arms. Similarly, in the LD setting, the Philips C-arm resulted in less ventral OSLD exposure (25,926 mrad) than both the Ziehm (30,956 mrad) and GE (38,209 mrad; p < 0.001) C-arms. Meanwhile, in the LDLP setting, the Ziehm C-arm showed less ventral OSLD exposure (4019 mrad) than both the GE (7418 mrad) and Philips (8229 mrad; p < 0.001) C-arms. All three manufacturers received adequate image quality ratings at the AEC and LD settings. However, at LDLP, the Ziehm C-arm received inadequate ratings in 8% of images, whereas both the GE and Philips C-arms received 100% adequate ratings (p = 0.016). Conclusions: Radiation produced by flat-panel C-arms varies dramatically, with the highest exposure (Ziehm) being almost double the lowest (Philips) in AEC. Improved picture quality at the lowest settings may come at the cost of increased radiation dose. Surgeons should carefully select the machine and settings to minimize radiation exposure while still preserving the image quality.

Comprehensive profiling of DNA methylation in Korean patients with colorectal cancer

Alterations in DNA methylation play an important pathophysiological role in the development and progression of colorectal cancer. We comprehensively profiled DNA methylation alterations in 165 Korean patients with colorectal cancer (CRC), and conducted an in-depth investigation of cancer-specific methylation patterns. Our analysis of the tumor samples revealed a significant presence of hypomethylated probes, primarily within the gene body regions; few hypermethylated sites were observed, which were mostly enriched in promoter-like and CpG island regions. The CpG Island Methylator PhenotypeHigh (CIMP-H) exhibited notable enrichment of microsatellite instability-high (MSI-H). Additionally, our findings indicated a significant correlation between methylation of the MLH1 gene and MSI-H status. Furthermore, we found that the CIMP-H had a higher tendency to affect the right-side of the colon tissues and was slightly more prevalent among older patients. Through our methylome profile analysis, we successfully verified the thylation patterns and clinical characteristics of Korean patients with CRC. This valuable dataset lays a strong foundation for exploring novel molecular insights and potential therapeutic targets for the treatment of CRC. [BMB Reports 2024; 57(2): 110-115].

Reducing hand radiation during renal access for percutaneous nephrolithotomy: a comparison of radiation reduction techniques

Percutaneous nephrolithotomy confers the highest radiation to the urologist's hands compared to other urologic procedures. This study compares radiation exposure to the surgeon's hand and patient's body when utilizing three different techniques for needle insertion during renal access. Simulated percutaneous renal access was performed using a cadaveric patient and separate cadaveric forearm representing the surgeon's hand. Three different needle-holding techniques were compared: conventional glove (control), a radiation-attenuating glove, and a novel needle holder. Five 300-s fluoroscopy trials were performed per treatment arm. The primary outcome was radiation dose (mSv) to the surgeon's hand. The secondary outcome was radiation dose to the patient. One-way ANOVA and Tukey's B post-hoc tests were performed with p < 0.05 considered significant. Compared to the control (3.92 mSv), both the radiation-attenuating glove (2.48 mSv) and the needle holder (1.37 mSv) reduced hand radiation exposure (p < 0.001). The needle holder reduced hand radiation compared to the radiation-attenuating glove (p < 0.001). The radiation-attenuating glove resulted in greater radiation produced by the C-arm compared to the needle holder (83.49 vs 69.22 mGy; p = 0.019). Patient radiation exposure was significantly higher with the radiation-attenuating glove compared to the needle holder (8.43 vs 7.03 mSv; p = 0.027). Though radiation-attenuating gloves decreased hand radiation dose by 37%, this came at the price of a 3% increase in patient exposure. In contrast, the needle holder reduced exposure to both the surgeon's hand by 65% and the patient by 14%. Thus, a well-designed low-density needle holder could optimize radiation safety for both surgeon and patient.

ERK2 phosphorylation of EBNA1 serine 383 residue is important for EBNA1-dependent transactivation

Functional inhibition of Epstein-Barr virus (EBV)-encoded nuclear antigen 1 (EBNA1) can cause the death of EBV infected cells. In this study, a bioinformatics tool predicted the existence of putative extracellular signal-regulated kinase (ERK) docking and substrate consensus sites on EBNA1, suggesting that ERK2 could bind to and phosphorylate EBNA1. In accordance, ERK2 was found to phosphorylate EBNA1 serine 383 in a reaction suppressed by H20 (a structural congener of the ERK inhibitor), U0126 (an inhibitor of MEK kinase), and mutations at substrate (S383A) or putative ERK docking sites. Wild-type (S383) and phosphomimetic (S383D) EBNA1 demonstrated comparable transactivation function, which was suppressed by H20 or U0126. In contrast, non-phosphorylated EBNA1 mutants displayed significantly impaired transactivation activity. ERK2 knock-down by siRNA, or treatment with U0126 or H20 repressed EBNA1-dependent transactivation. Collectively, these data indicate that blocking ERK2-directed phosphorylation can suppress EBNA1-transactivation function in latent EBV-infected cells, validating ERK2 as a drug target for EBV-associated disorders.

High-performance liquid chromatographic determination of trimebutine and its major metabolite, N-monodesmethyl trimebutine, in rat and human plasma

A rapid, selective and very sensitive ion-pairing reversed-phase HPLC method was developed for the simultaneous determination of trimebutine (TMB) and its major metabolite, N-monodesmethyltrimebutine (NDTMB), in rat and human plasma. Heptanesulfonate was employed as the ion-pairing agent and verapamil was used as the internal standard. The method involved the extraction with a n-hexane-isopropylalcohol (IPA) mixture (99:1, v/v) followed by back-extraction into 0.1 M hydrochloric acid and evaporation to dryness. HPLC analysis was carried out using a 4-microm particle size, C18-bonded silica column and water-sodium acetate-heptanesulfonate-acetonitrile as the mobile phase and UV detection at 267 nm. The chromatograms showed good resolution and sensitivity and no interference of plasma. The mean recoveries for human plasma were 95.4+/-3.1% for TMB and 89.4+/-4.1% for NDTMB. The detection limits of TMB and its metabolite, NDTMB, in human plasma were 1 and 5 ng/ml, respectively. The calibration curves were linear over the concentration range 10-5000 ng/ml for TMB and 25-25000 ng/ml for NDTMB with correlation coefficients greater than 0.999 and with within-day or between-day coefficients of variation not exceeding 9.4%. This assay procedure was applied to the study of metabolite pharmacokinetics of TMB in rat and the human.

No effect of diltiazem on the hepatic clearance of indocyanine green in the rats

In order to investigate the effect of the pretreatment with various doses of diltiazem (DTZ) on the pharmacokinetics of indocyanine green (ICG) at steady state, especially the hepatic blood clearance due to the change of hepatic blood flow, the following experiments were carried out with ICG, a hepatic function test marker, not metabolized in liver and only excreted in bile. The intravenous bolus injection (3,780 micrograms/kg) and the constant-rate infusion (10,100 micrograms/kg/hr) of ICG into the left femoral vein were made in order to check the steady-state plasma concentration (Css of 10 micrograms/ml) of ICG at 20, 25 and 30 min. Following a 90-min washout period, the intravenous bolus injection (108, 430, 860 and 1,720 micrograms/kg) and the constant-rate infusion (108, 433, 866 and 1,730 micrograms/kg/hr) of DTZ into the right femoral vein were made and the achievement of the steady-state plasma levels (Css of 50, 200, 400 and 800 ng/ml) of DTZ were conformed at 60, 70 and 80 min. During the steady state of DTZ, the intravenous bolus injection (3,780 micrograms/kg) and the constant-rate infusion (10,200 micrograms/kg/hr) of ICG into the left femoral vein were made and also the steady-state plasma concentration of ICG was checked at 20, 25 and 30 min. The plasma concentrations of DTZ and ICG were determined using a high performance liquid chromatographic technique. At the steady state, the hepatic blood clearance of ICG was obtained from the plasma concentration and blood-to-plasma concentration ratio (RB) of ICG. The pretreatment with various doses of DTZ did not influence the plasma concentrations, RB and plasma free fraction (fp) of ICG. So the hepatic blood clearance of ICG was independent of concentration of DTZ. The hepatic blood clearance of ICG could be affected by both hepatic blood flow and hepatic intrinsic clearance. But there was no change of the hepatic blood clearance of ICG between the control and the DTZ-pretreated rats in this study. So it may be suggested that DTZ does not influence hepatic blood flow.