[Comparison of ultrathin bronchoscopy with conventional bronchoscopy for the diagnostic value of peripheral pulmonary lesions].

Objective: To assess and compare the diagnostic efficacy of next-generation ultrathin bronchoscopy (UTB) and conventional bronchoscopy (CB), both combined with radial endobronchial ultrasound (r-EBUS), in the evaluation of peripheral pulmonary lesions (PPL). Methods: A cohort of 39 patients with PPL who underwent multimodal bronchoscopy at Dushu Lake Hospital, Soochow University, from June 1, 2021 to May 31, 2023 was consecutively enrolled. A single bronchoscopist performed multimodal bronchoscopies using CB (external diameter 4.9 mm or 5.9 mm, working channel diameter 2 or 3 mm, CB group) for transbronchial biopsy under r-EBUS guidance (rEBUS-TBLB), followed by UTB (external diameter 3 mm, working channel diameter 1.7 mm, UTB group) for transbronchial biopsy under r-EBUS guidance. Pathological findings and a 6-month clinical follow-up were used as the gold standard to compare the diagnostic yield of biopsy specimens, ultrasound characteristics, and localization rates of the two bronchoscope types. The aim was to evaluate the clinical application value of UTB combined with r-EBUS. Binary variables were analysed using the McNemar test for paired data. Continuous variables or ranked data were analysed using the Wilcoxon signed-rank test for paired data. Results: The diagnostic yields for UTB and CB groups were 66.67% (26/39) and 30.77% (12/39), respectively, with the UTB group significantly surpassing the CB group (χ2=10.56, P=0.001, 1-ß=0.968). r-EBUS with CB exhibited no visible lesion in 13 cases, adjacent to the lesion in 19 cases, and within the lesion in 7 cases.Substitution of UTB resulted in r-EBUS images changing from no visible lesion to adjacent to the lesion in 7 cases, from no visible lesion to within the lesion in 3 cases, and from adjacent to the lesion to within the lesion in 12 cases. The positioning of the r-EBUS probe in relation to the lesions improved significantly with UTB usage (Z=-4.46, P<0.001). Localization rates (number of patients with "within" or "adjacent to" the image/total number of patients) for UTB and CB were 92.30% (36/39) and 66.67% (26/39), respectively (χ2=8.10, P=0.002). UTB improved r-EBUS probe localization rates. The diagnostic yields of UTB were higher than CB for solid lesions, lesions>30 mm in diameter, non-upper lobar location, benign or malignant lesions and lesions with or without a bronchus sign. Conclusion: The UTB group demonstrated a significantly higher diagnostic yield than the CB group, providing superior r-EBUS probe images, and a significant diagnostic advantage for PPL.

Combined modalities of resistance in an oxaliplatin-resistant human gastric cancer cell line with enhanced sensitivity to 5-fluorouracil.

To identify mechanisms underlying oxaliplatin resistance, a subline of the human gastric adenocarcinoma TSGH cell line, S3, was made resistant to oxaliplatin by continuous selection against increasing drug concentrations. Compared with the parental TSGH cells, the S3 subline showed 58-fold resistance to oxaliplatin; it also displayed 11-, 2-, and 4.7-fold resistance to cis-diammine-dichloroplatinum (II) (CDDP), copper sulphate, and arsenic trioxide, respectively. Interestingly, S3 cells were fourfold more susceptible to 5-fluorouracil-induced cytotoxicity due to downregulation of thymidylate synthase. Despite elevated glutathione levels in S3 cells, there was no alteration of resistant phenotype to oxaliplatin or CDDP when cells were co-treated with glutathione-depleting agent, l-buthionine-(S,R)-sulphoximine. Cellular CDDP and oxaliplatin accumulation was decreased in S3 cells. In addition, amounts of oxaliplatin- and CDDP-DNA adducts in S3 cells were about 15 and 40% of those seen with TSGH cells, respectively. Western blot analysis showed increased the expression level of copper transporter ATP7A in S3 cells compared with TSGH cells. Partial reversal of the resistance of S3 cells to oxaliplatin and CDDP was observed by treating cell with ATP7A-targeted siRNA oligonucleotides or P-type ATPase-inhibitor sodium orthovanadate. Besides, host reactivation assay revealed enhanced repair of oxaliplatin- or CDDP-damaged DNA in S3 cells compared with TSGH cells. Together, our results show that the mechanism responsible for oxaliplatin and CDDP resistance in S3 cells is the combination of increased DNA repair and overexpression of ATP7A. Downregulation of thymidylate synthase in S3 cells renders them more susceptible to 5-fluorouracil-induced cytotoxicity. These findings could pave ways for future efforts to overcome oxaliplatin resistance.