A perfusion chamber for monitoring transepithelial NaCl transport in an in vitro model of the renal tubule.

Transepithelial electrical measurements in the renal tubule have provided a better understanding of how kidney regulates electrolyte and water homeostasis through the reabsorption of molecules and ions (e.g., H2 O and NaCl). While experiments and measurement techniques using native tissue are difficult to prepare and to reproduce, cell cultures conducted largely with the Ussing chamber lack the effect of fluid shear stress which is a key physiological stimulus in the renal tubule. To overcome these limitations, we present a modular perfusion chamber for long-term culture of renal epithelial cells under flow that allows the continuous and simultaneous monitoring of both transepithelial electrical parameters and transepithelial NaCl transport. The latter is obtained from electrical conductivity measurements since Na+ and Cl- are the ions that contribute most to the electrical conductivity of a standard physiological solution. The system was validated with epithelial monolayers of raTAL and NRK-52E cells that were characterized electrophysiologically for 5 days under different flow conditions (i.e., apical perfusion, basal, or both). In addition, apical to basal chemical gradients of NaCl (140/70 and 70/140 mM) were imposed in order to demonstrate the feasibility of this methodology for quantifying and monitoring in real time the transepithelial reabsorption of NaCl, which is a primary function of the renal tubule.

MicroRNA-31 Emerges as a Predictive Biomarker of Pathological Response and Outcome in Locally Advanced Rectal Cancer.

Neoadjuvant chemoradiotherapy (CRT) followed by total mesorectal excision has emerged as the standard treatment for locally advanced rectal cancer (LARC) patients. However, many cases do not respond to neoadjuvant CRT, suffering unnecessary toxicities and surgery delays. Thus, identification of predictive biomarkers for neoadjuvant CRT is a current clinical need. In the present study, microRNA-31 expression was measured in formalin-fixed paraffin-embedded (FFPE) biopsies from 78 patients diagnosed with LARC who were treated with neoadjuvant CRT. Then, the obtained results were correlated with clinical and pathological characteristics and outcome. High microRNA-31 (miR-31) levels were found overexpressed in 34.2% of cases. Its overexpression significantly predicted poor pathological response (p = 0.018) and worse overall survival (OS) (p = 0.008). The odds ratio for no pathological response among patients with miR-31 overexpression was 0.18 (Confidence Interval = 0.06 to 0.57; p = 0.003). Multivariate analysis corroborated the clinical impact of miR-31 in determining pathological response to neoadjuvant CRT as well as OS. Altogether, miR-31 quantification emerges as a novel valuable clinical tool to predict both pathological response and outcome in LARC patients.

MicroRNA-21 predicts response to preoperative chemoradiotherapy in locally advanced rectal cancer.

PURPOSE: The treatment of choice for locally advanced rectal cancer is preoperative chemoradiotherapy. Despite half of patients do not respond and suffer unnecessary toxicities and surgery delays, there are no biomarkers to guide preoperative CRT outcome. MicroRNA-21 has been related to acquisition of 5-fluorouracil resistance; however, its potential predictive value of response to preoperative chemoradiotherapy in locally advanced rectal cancer remains unknown. METHODS: Nighty-two patients diagnosed with locally advanced rectal cancer who were preoperatively treated with chemoradiotherapy were selected for this study. Moreover, microRNA-21 expression was quantified in formalin-fixed paraffin-embedded biopsies from this cohort, and the results obtained were correlated with clinical and molecular characteristics, pathological response, and outcome. RESULTS: MicroRNA-21 was found overexpressed in 77.6% cases, and significantly correlated with tumor grade after preoperative chemoradiotherapy (P = 0.013) and with pathological response (P = 0.013). The odds ratio of having miR-21 overexpression and not getting a respond to chemoradiotherapy resulted in 9.75 CI 2.24 to 42. Sensitivity, specificity, negative predictive values, and positive predictive value were 86.6, 60, 42.8, and 92%, respectively. Multivariate analysis confirmed the clinical significance of miR-21 determining preoperative chemoradiotherapy response. CONCLUSIONS: MicroRNA-21 expression efficiently predicts preoperative chemoradiotherapy pathological response in locally advanced rectal cancer.

Facilitation of accurate and effective radiation therapy using fentanyl pectin nasal spray (FPNS) to reduce incidental breakthrough pain due to procedure positioning.

PURPOSE: To provide effective and accurate radiotherapy (RT) for advanced cancer patients who experience breakthrough pain (BP) due to positioning manoeuvres, through the use of FPNS. Secondary endpoints were the dose and time required to achieve a 50% numeric rating scale (NRS) reduction and conduction of a pharmacoeconomic analysis. PATIENTS AND METHODS: Twenty-seven advanced cancer patients with moderate-severe BP associated with routine radiotherapy procedures and manoeuvres were selected to receive FPNS. Most patients (20/27) had bone metastases. The patients showed a low Karnovsky performance status (mean 54%; range: 30-80). BP intensity was scored with the NRS before and after the procedures that triggered it. All patients were already receiving opioid baseline treatment at a total dose equivalent to 40-160mg oral morphine. Before the procedure, BP was treated with 100-400µg of FPNS. Data related to tolerance, pain relief, onset of the relief and efficient dose to allow RT to proceed were collected. RESULTS: In 26 patients the BP score was reduced by at least 50% as determined in 15.5min (range 8-35min) after fentanyl pectin intranasal administration, and pain relief started after 7min (range 3-15min); p<0.05 in both cases. The duration of pain reduction facilitated the proceeding of RT. The Mean NRS score before the procedure was 9 (95%CI: 8.6-9.4) and decreased during procedure to 3 (95%CI: 2.5-3.8). The average dose of FPNS for most patients was 100-200µg to achieve pain control, except in three patients who required progressive doses of up to 300-400µg. After receiving 300µg, one patient dropped out of the study due to severe adverse effects (nausea). Seven patients reported minor undesirable effects related to FPNS administration. CONCLUSIONS AND IMPLICATIONS: Certain necessary RT procedures in advanced cancer patients can cause severe BP episodes. A simple, safe, fast acting and strong analgesic is needed. FPNS is a rapidly absorbed opioid analgesic with a pain relief profile that would be particularly well suited for this patient population. By reducing BP, the drug enables the completion of necessary RT procedures without needless patient discomfort. When BP is attenuated, Department productivity is maintained and unnecessary delays are avoided. Further studies and clinical trials are needed to assess therapeutic FPNS dosages with a view to defining efficacy in the correct clinical context.