Following in situ photoinitiated polymerization of multifunctional acrylic monomers by fluorescence and photocalorimetry simultaneously

The photoinitiated polymerization of multifunctional (meth)acrylic monomers was simultaneously monitored in real time by fluorescence and differential scanning calorimetry. As the curing proceeds, the fluorescence emission changes due to an increase in the viscosity of the microenvironment. A good correlation between fluorescence intensity and degree of conversion was established by using two different fluorescent probes, each having the same fluorophore, dialkylamino derivatives of 7-nitro-2-oxa-1,3-diazol. One of the probes contains an acrylic moiety which can react with the monomers labelling the formed network. The use of the first moment of fluorescence is presented as a suitable methodology to avoid experimental fluctuations. Furthermore, the influence of the length of the spacer between the acrylic groups in the polymerization reaction kinetics and fluorescence changes has been also discussed in terms of reaction diffusion controlled termination kinetics and free volume fraction. It was concluded that the fluorescence method is a powerful tool to study the kinetics of photopolymerization of multifunctional monomers.The authors would like to thank the Union European Commission for funding through the BRITE-Euram Project (BE97-4472). Gratitude is also extended to Plan Nacional I+D+I (Ministerio de Ciencia y Tecnologı́a) for financial support (MAT1998-0518-CE and MAT2000-1671). We thank to Dr K. Dietliker, from Ciba Speciality Chemicals, for providing the photoinitiators. The authors are grateful to Valentı́n Guadaño from Lasing for helpful discussions regarding to the optical coupling between the calorimeter and spectrofluorimeter. J. Baselga wishes to thank CAM (PRICIT Programme)

Oncological safety of transanal total mesorectal excision (TaTME) for rectal cancer: mid-term results of a prospective multicentre study

Background There is no consensus regarding the gold standard technique for rectal cancer as Total Mesorectal Excision (TME) may be safely performed either by open or minimally invasive surgery. The laparoscopic approach, however, may carry technical difficulties. For this reason, a novel technique has emerged in the last decade combining a dual laparoscopic dissection (abdominal and transanal) to perform the TME technique (TaTME). When focusing on oncological outcomes, there is a lack of literature regarding mid-long term results. The aim of this study is to evaluate the mid-term oncological impact of TaTME for treating rectal cancer. Methods A prospective multicentre study was performed in four tertiary centres including consecutive patients who underwent TaTME for mid-low rectal cancer by the same group of experienced surgeons. The analysed data included pathological results on the quality of TME and mid-term oncological outcomes. Results In total, 173 patients were included throughout a study period of 6 years. Our series included 70% males and 68% of patients with neoadjuvant treatments. The median follow-up was 23 [15–37.5] months. Regarding pathological results, a complete TME was achieved in 72.8%, while circumferential and distal margins were affected in 1.4 and 1.1%, respectively. Five patients developed local recurrences (3%) and 8.1% presented distant disease during the follow-up. The 2-year disease-free survival and the overall survival rates were 88% and 95%, respectively. Conclusions There is currently a lack of evidence in the literature regarding TaTME and oncological outcomes with no data available from randomized clinical trials. In the meantime, the reported results from different multicentre series are controversial. This study showed positive mid-term outcomes at 2 years of follow-up and supported notable oncological outcomes with TaTME. However, it must be emphasized that previous experience in minimally invasive and transanal surgeries is essential for surgeons before intending to perform TaTME

Impact of Routine and Long-Term Follow-Up on Weight Loss after Bariatric Surgery

Background: Weight loss after bariatric surgery varies among patients. Patients who do not complete long-term follow-up are considered to loose less weight than those with regular follow-up visits. Objective: To evaluate the influence of patients' follow-up compliance on long-term excess weight loss (%EWL) and total weight loss (%TWL) after bariatric surgery, comparing results between gastric bypass (GB) and sleeve gastrectomy (SG). Methods: Patients with up to 5 years of follow-up data after bariatric surgery were included in this retrospective analysis. Patients were divided in 2 groups: those in group 1 who had attended every scheduled postoperative appointment and those in group 2 who had been lost to follow-up before 1 year and were later contacted by telephone. %EWL and %TWL were compared to determine the possible relationship between type of surgery and regularity of the follow-up. Results: A total of 385 patients were included. A significant difference in EWL was observed at 5 years in the SG group (78% for group 1 versus 39% for group 2; p = 0.02) and GB group (75% for group 1 versus 62% for group 2; p = 0.01). No significant differences between surgeries were found when comparing long-term EWL in group 1 patients 77% for SG versus 75% for GB. For group 2 patients, GB achieved greater EWL than SG; p = 0.005. %TWL patients in group 2 showed significant differences in all periods of study (p < 0.05). Conclusion: Bariatric surgery patients who attended all scheduled follow-up appointments experienced significantly greater long-term EWL and TWL than those who did not. GB has apparent increased benefits for weight loss in long-term follow-up when compared with SG for patients who did not attend long-term follow-up. Therefore, continued long-term follow-up of bariatric patients should be encouraged to increase postoperative weight loss results

Practice-oriented solutions integrating intraoperative electron irradiation and personalized proton therapy for recurrent or unresectable cancers: Proof of concept and potential for dual FLASH effect

Background: Oligo-recurrent disease has a consolidated evidence of long-term surviving patients due to the use of intense local cancer therapy. The latter combines real-time surgical exploration/resection with high-energy electron beam single dose of irradiation. This results in a very precise radiation dose deposit, which is an essential element of contemporary multidisciplinary individualized oncology. Methods: Patient candidates to proton therapy were evaluated in Multidisciplinary Tumor Board to consider improved treatment options based on the institutional resources and expertise. Proton therapy was delivered by a synchrotron-based pencil beam scanning technology with energy levels from 70.2 to 228.7 MeV, whereas intraoperative electrons were generated in a miniaturized linear accelerator with dose rates ranging from 22 to 36 Gy/min (at Dmax) and energies from 6 to 12 MeV. Results: In a period of 24 months, 327 patients were treated with proton therapy: 218 were adults, 97 had recurrent cancer, and 54 required re-irradiation. The specific radiation modalities selected in five cases included an integral strategy to optimize the local disease management by the combination of surgery, intraoperative electron boost, and external pencil beam proton therapy as components of the radiotherapy management. Recurrent cancer was present in four cases (cervix, sarcoma, melanoma, and rectum), and one patient had a primary unresectable locally advanced pancreatic adenocarcinoma. In re-irradiated patients (cervix and rectum), a tentative radical total dose was achieved by integrating beams of electrons (ranging from 10- to 20-Gy single dose) and protons (30 to 54-Gy Relative Biological Effectiveness (RBE), in 10–25 fractions). Conclusions: Individual case solution strategies combining intraoperative electron radiation therapy and proton therapy for patients with oligo-recurrent or unresectable localized cancer are feasible. The potential of this combination can be clinically explored with electron and proton FLASH beams