RESUMO
Neoadjuvant chemotherapy (NAC) has become a standard treatment for borderline resectable pancreatic ductal adenocarcinoma (PDAC). The present study examined the maximum tolerated dose of NAC with gemcitabine plus nab-paclitaxel (GnP) in patients with resectable PDAC. Between 2015 and 2019, 39 patients with resectable PDAC were enrolled in the present study. GnP was administered for two 28-day cycles on days 1, 8 and 15. The planned doses for levels 1, 2 and 3 were 75, 100 and 125 mg/m2, respectively, for nab-paclitaxel and 600, 800 and 1,000 mg/m2, respectively, for gemcitabine. Dose-limiting toxicity (neutropenia, anemia, thrombocytopenia and/or liver injury) was observed in 44.4% of patients treated at dose level 1 (21 patients) and 60.0% of those treated at dose level 2 (18 patients). Therefore, the maximum tolerated dose was set as level 1. Six patients withdrew from protocol treatment because of non-hematologic adverse events (skin rash, pancreatitis and biliary tract infection). Among the 31 patients with pathologically confirmed PDAC, partial response, stable disease and disease progression were recorded in 4 (12.9%), 24 (77.4%) and 3 (9.7%) patients, respectively. NAC significantly reduced tumor size according to computed tomography, and CA19-9 levels and the 18F-fluorodeoxyglucose maximum standardized uptake value were decreased in positron emission tomography. No postoperative complications attributable to NAC were recognized. Among the 27 patients with PDAC who underwent resection, the pathological treatment effect was judged as grades Ia, Ib and II in 21 (77.8%), 4 (14.8%) and 2 (7.4%) patients, respectively. R0 resection was performed in 24 out of 27 patients (88.9%). Adjuvant chemotherapy with oral S-1 was administered to 21 out of 27 patients (77.8%). In conclusion, NAC with GnP was safe and feasible for resectable PDAC at dose level 1. In the future, verification of the long-term results of the present study will be necessary, and a phase II clinical trial is anticipated.
RESUMO
An excised patch membrane sensor for arachidonic acid (AA) is described, whose response stems from AA-induced channel-type transport of ions across the excised patch membrane. The patch membrane sensor was prepared in situ by excising mouse hippocampal cell membranes with patch pipets having a tip diameter of < 0.5 microm. The sensor responds to AA, giving rise to a channel-type current, and its magnitude (apparent conductance) increased with increasing AA concentration in the range from 10 to 30 nM. The detection limit was 2.1 nM (S/N = 3). The induction of channel-type currents was selective to AA over fatty acids such as palmitic acid, stearic acid, oleic acid, gamma-linolenic acid, and docosahexaenoic acid and AA metabolites such as 12-HETE, 5-HETE, and prostaglandin D(2). The sensor was applied to quantification of AA released from various neuronal regions (CA1, CA3, and DG) of mouse hippocampus under stimulation of 100 microM L-glutamate. The release of AA from each region was observed 1 min after the stimulation and the concentration of AA 5 min after the stimulation varied among the neuronal sites, i.e., 8+/-1 nM (n = 5) for CA1, 15+/-3 nM (n = 3) for CA3, and 6+/-2 nM (n = 9) for DG. The L-glutamate-evoked release of AA was partly inhibited by ionotropic glutamate receptor antagonists (APV and DNQX) and completely blocked by phospholipase A2 (PLA2) inhibitor (MAFP), suggesting that the release of AA occurred by glutamate receptor-mediated activation of PLA2. The potential use of the present sensor for detecting local concentration of AA at various neuronal sites is discussed.
