Adjuvant 5-fluorouracil and portal vein infusion chemotherapy followed by gemcitabine for pancreatic cancer.

BACKGROUND: Although adjuvant gemcitabine (GEM) monotherapy improves the overall survival (OS) of patients with resected pancreatic cancer, its efficacy requires further improvement. This multicenter, phase II study investigated the efficacy of adjuvant portal vein infusion (PVI) chemotherapy followed by GEM therapy in patients with resected pancreatic cancer. METHODS: 5-fluorouracil (250 mg/day) and heparin (2000 IU/day) PVI chemotherapy were combined with systemic administration of mitomycin C (4 mg; days 6, 13, 20, and 27) and cisplatin (10 mg; days 7, 14, 21, and 28) for 4 weeks (PI4W), followed by GEM (1000 mg/m2; days 1, 8, and 15 every 4 weeks for 6 months). The primary endpoint was relapse-free survival (RFS) and the secondary endpoints were OS and treatment completion. RESULTS: Between November 2010 and August 2013, 53 patients who underwent complete resection were enrolled, including 30, 20, and 3 patients who underwent pancreaticoduodenectomies and distal and total pancreatectomies, respectively. In total, 51 (96.2%) patients underwent R0 resection, of whom 3, 2, 12, 35, 0, and 1 had stages IA, IB, IIA, IIB, III, and IV cancer, respectively, and 47 (88.7%) patients completed PI4W. The median RFS was 22.0 months (1-, 3-, 5, and 10 years RFS: 64.9%, 38.1%, 38.1%, and 38.1%, respectively), whereas the median OS was 32.0 months (1-, 3-, 5, and 10 years OS:86.6%, 47.2%, 44.4%, and 44.4%, respectively). CONCLUSION: Treatment with PI4W followed by GEM for 6 months after surgery may be beneficial in patients undergoing curative resection of pancreatic cancer.

An unusual cytological presentation of solid pseudopapillary neoplasm of the pancreas mimicking adenoid cystic carcinoma: a case report and literature review.

Endoscopic ultrasound-guided fine-needle aspiration has become the common procedure for the diagnosis of pancreatic mass, and cytological examination is usually the first approach. Solid pseudopapillary neoplasm (SPN) cytologically represents papillary structures of branching capillaries surrounded by discohesive neoplastic cells. However, it may present various degrees of tissue degeneration, causing diagnostic challenges. Here, we report a 21-year-old female who had a 2-cm-sized mass in the pancreas head. Cytological examination revealed clumps of small round/oval cells that represented microcystic configurations with mucus, mimicking adenoid cystic carcinoma or mucinous adenocarcinoma. Cercariform cells, nuclear grooves/folding, and cytoplasmic vacuoles were not observed. Histopathological examination revealed confluent small glandular structures containing acidic mucus. The tumor cells were positively stained for ß-catenin, CD10, and CD56, and negative for chromogranin A and E-cadherin, suggesting SPN, micropseudocystic variant. This variant has been scarcely described, but we should recognize it for accurate cytological triage of pancreatic tumors.

Two-electron Rabi oscillations in real-time time-dependent density-functional theory.

We investigate the Rabi oscillations of electrons excited by an applied electric field in several simple molecular systems using time-dependent configuration interaction (TDCI) and real-time time-dependent density-functional theory (RT-TDDFT) dynamics. While the TDCI simulations exhibit the expected single-electron Rabi oscillations at a single resonant electric field frequency, Rabi oscillations in the RT-TDDFT simulations are a two-electron process. The existence of two-electron Rabi oscillations is determined both by full population inversion between field-free molecular orbitals and the behavior of the instantaneous dipole moment during the simulations. Furthermore, the Rabi oscillations in RT-TDDFT are subject to an intensity threshold of the electric field, below which Rabi oscillations do not occur and above which the two-electron Rabi oscillations occur at a broad range of frequencies. It is also shown that at field intensities near the threshold intensity, the field frequency predicted to induce Rabi oscillations by linear response TDDFT only produces detuned Rabi oscillations. Instead, the field frequency that yields the full two-electron population inversion and Rabi oscillation behavior is shown to be the average of single-electron transition frequencies from the ground S0 state and the doubly-excited S2 state. The behavior of the two-electron Rabi oscillations is rationalized via two possible models. The first model is a multi-photon process that results from the electric field interacting with the three level system such that three level Rabi oscillations may occur. The second model suggests that the mean-field nature of RT-TDDFT induces paired electron propagation.

Optimal cooperative searching using purely repulsive interactions.

Foraging, either solitarily or collectively, is a necessary behavior for survival that is demonstrated by many organisms. Foraging can be collectively optimized by utilizing communication between the organisms. Examples of such communication range from high level strategic foraging by animal groups to rudimentary signaling among unicellular organisms. Here we systematically study the simplest form of communication via long range repulsive interactions between multiple diffusing Brownian searchers on a one-dimensional lattice. We show that the mean first passage time for any one of them to reach a fixed target depends non-monotonically on the range of the interaction and can be optimized for a repulsive range that is comparable to the average spacing between searchers. Our results suggest that even the most rudimentary form of collective searching does in fact lower the search time for the foragers suggesting robust mechanisms for search optimization in cellular communities.

The influence of donor age on liver regeneration and hepatic progenitor cell populations.

BACKGROUND: Recent reports suggest that donor age might have a major impact on recipient outcome in adult living donor liver transplantation (LDLT), but the reasons underlying this effect remain unclear. The aims of this study were to compare liver regeneration between young and aged living donors and to evaluate the number of Thy-1+ cells, which have been reported to be human hepatic progenitor cells. METHODS: LDLT donors were divided into 2 groups (Group O, donor age ≥ 50 years, n = 6 and Group Y, donor age ≤ 30 years, n = 9). The remnant liver regeneration rates were calculated on the basis of computed tomography volumetry on postoperative days 7 and 30. Liver tissue samples were obtained from donors undergoing routine liver biopsy or patients undergoing partial hepatectomy for metastatic liver tumors. Thy-1+ cells were isolated and counted using immunomagnetic activated cell sorting (MACS) technique. RESULTS: Donor liver regeneration rates were significantly higher in young donors compared to old donors (P = .042) on postoperative day 7. Regeneration rates were significantly higher after right lobe resection compared to rates after left lobe resection. The MACS findings showed that the number of Thy-1+ cells in the human liver consistently tended to decline with age. CONCLUSION: Our study revealed that liver regeneration is impaired with age after donor hepatectomy, especially after right lobe resection. The declining hepatic progenitor cell population might be one of the reasons for impaired liver regeneration in aged donors.