Robotic Ultrasound-Guided Central Pancreatectomy with Main Pancreatic Duct Endoscopy Evaluation for High-Risk, Mixed-Type Intraductal Papillary Mucinous Neoplasm.

BACKGROUND: Central pancreatectomy (CP) is a parenchymal-sparing technique indicated for the resection of selected lesions of the neck or proximal body of the pancreas.1,2 The risk of postoperative complications is theoretically doubled because the surgeon has to manage two cut surfaces of the pancreas. The video shows a fully robotic CP to treat a 62-year-old male patient with a mixed-type intraductal papillary mucinous neoplasm (IPMN) of the pancreatic neck, using ultrasound (US) and Wirsung endoscopic evaluation to guide the pancreatic resection and ensure optimal resection margins. MATERIALS AND METHODS: A US-guided robotic CP was carried out, and an intraoperative endoscopic evaluation of the MPD was performed to determine the distal transection level. A transmesocolic, end-to-side, robot-sewn Wirsung-jejunostomy with internal MPD stenting was then created. The procedure was completed with a side-to-side jejunojejunostomy. RESULTS: The operative time was 290 min, with negligible blood loss. During the postoperative course, the patient experienced bleeding from a branch of the gastroduodenal artery with subsequent fluid collection, which was successfully treated with angioembolization and percutaneous drainage. He was discharged home on postoperative day 22. Final pathology revealed a non-invasive IPMN with low-grade dysplasia and free surgical margins. At 12 months of follow-up, the patient was doing well, with no evidence of local recurrence and endocrine or exocrine pancreatic insufficiency. CONCLUSIONS: The combination of robotic surgery with intraoperative US and Wirsungoscopy may offer distinct technical advantages for challenging pancreatectomies that follow the principles of parenchymal-sparing surgery.

Robotic Distal Pancreatectomy: A Novel Standard of Care? Benchmark Values for Surgical Outcomes From 16 International Expert Centers.

BACKGROUND AND OBJECTIVE: Robotic distal pancreatectomy (DP) is an emerging attractive approach, but its role compared with laparoscopic or open surgery remains unclear. Benchmark values are novel and objective tools for such comparisons. The aim of this study was to identify benchmark cutoffs for many outcome parameters for DP with or without splenectomy beyond the learning curve. METHODS: This study analyzed outcomes from international expert centers from patients undergoing robotic DP for malignant or benign lesions. After excluding the first 10 cases in each center to reduce the effect of the learning curve, consecutive patients were included from the start of robotic DP up to June 2020. Benchmark patients had no significant comorbidities. Benchmark cutoff values were derived from the 75th or the 25th percentile of the median values of all benchmark centers. Benchmark values were compared with a laparoscopic control group from 4 high-volume centers and published open DP landmark series. RESULTS: Sixteen centers contributed 755 cases, whereof 345 benchmark patients (46%) were included the analysis. Benchmark cutoffs included: operation time ≤300 minutes, conversion rate ≤3%, clinically relevant postoperative pancreatic fistula ≤32%, 3 months major complication rate ≤26.7%, and lymph node retrieval ≥9. The comprehensive complication index at 3 months was ≤8.7 without deterioration thereafter. Compared with robotic DP, laparoscopy had significantly higher conversion rates (5×) and overall complications, while open DP was associated with more blood loss and longer hospital stay. CONCLUSION: This first benchmark study demonstrates that robotic DP provides superior postoperative outcomes compared with laparoscopic and open DP. Robotic DP may be expected to become the approach of choice in minimally invasive DP.

Redox Properties and in Vivo Magnetic Resonance Imaging of Cyclodextrin-Polynitroxides Contrast Agents.

This paper reports the synthesis, characterization and in vivo application of water-soluble supramolecular contrast agents (Mw: 5-5.6 kDa) for MRI obtained from ß-cyclodextrin functionalized with different kinds of nitroxide radicals, both with piperidine structure (CD2 and CD3) and with pyrrolidine structure (CD4 and CD5). As to the stability of the radicals in presence of ascorbic acid, CD4 and CD5 have low second order kinetic constants (≤0.05 M-1 s-1 ) compared to CD2 (3.5 M-1 s-1 ) and CD3 (0.73 M-1 s-1 ). Relaxivity (r1 ) measurements on compounds CD3-CD5 were carried out at different magnetic field strength (0.7, 3, 7 and 9.4 T). At 0.7 T, r1 values comprised between 1.5 mM-1 s-1 and 1.9 mM-1 s-1 were found while a significant reduction was observed at higher fields (r1 ≈0.6-0.9 mM-1 s-1 at 9.4 T). Tests in vitro on HEK293 human embryonic kidney cells, L929 mouse fibroblasts and U87 glioblastoma cells indicated that all compounds were non-cytotoxic at concentrations below 1 µmol mL-1 . MRI in vivo was carried out at 9.4 T on glioma-bearing rats using the compounds CD3-CD5. The experiments showed a good lowering of T1 relaxation in tumor with a retention of the contrast for at least 60 mins confirming improved stability also in vivo conditions.

Further validation and psychometric properties of the Spanish adaptation of the Genetic Counseling Outcome Scale.

Evaluation of clinical genetic services is challenging due to the nature of their interventions. The Genetic Counseling Outcome Scale (GCOS-24), a patient-reported outcome measure, was developed to measure empowerment, an important patient-reported outcome from genetic counseling. Previously, we translated and adapted GCOS-24 for use in Spain, but neither test-retest reliability nor structural and construct validity were assessed at that time. In the present study, we set out to test the reliability and validity of the Spanish adaptation of the GCOS-24 against already validated Spanish language measures of satisfaction with life, anxiety, and health locus of control. 880 patients/families who attended the genetics clinic were invited to participate in a online survey. 201 participants (23%) completed the four questionnaires at the first timepoint, and 59 of these (29%) completed GCOS-24 again the second timepoint, 2-4 weeks later. Test-retest reliability was confirmed, with no significant differences between responses to GCOS-24 at the first and second timepoints and good internal consistency. Convergent validity was confirmed between GCOS-24 and measures of satisfaction with life and anxiety but not with measures of health locus of control. For the structural and construct validation, an exploratory factor analysis was performed. The resulting factorial structure of GCOS-24 consists of 6 factors that accumulate 68% of the variance shared by the 21 items that remained in the model. We applied the factor structure of the three validated measures to the available data and analyzed the correlation between factors of GCOS-24 and the other scales. The results showed significant and consistent correlation with factors of the satisfaction with life and anxiety scales but no significant correlation with internal health locus of control. The use of the Spanish adaptation of GCOS-24 in other genetic clinics in Spain will help to validate it further. This study contributes to the international validation of GCOS-24 to evaluate the quality of genetic counseling in Europe.

Control of Electron Transfer Processes in Multidimensional Arylamine-Based Mixed-Valence Compounds by Molecular Backbone Design.

Four trigonal topology compounds with three diarylamines redox centers and dibenzofulvene as core bridge have been synthesized. Their radical cations exhibit appealing intramolecular electron transfer pathways between three redox centers, depending on their position on the core bridge. By changing such positions (on either 2,7- or 3,6-), and the length of the bridge, the control of the intramolecular electron transfer pathways was achieved through the electron self-exchange route. These processes were investigated by absorption spectroscopy, electron paramagnetic resonance spectroscopy, and (time-dependent) density functional theory calculations. Hole mobility measurements were carried out as well, to correlate the intramolecular electron transfer with the hole-transporting ability for possible applications in optoelectronic devices.

Peptide-Driven Charge-Transfer Organogels Built from Synergetic Hydrogen Bonding and Pyrene-Naphthalenediimide Donor-Acceptor Interactions.

The peptide-driven formation of charge transfer (CT) supramolecular gels featuring both directional hydrogen-bonding and donor-acceptor (D-A) complexation is reported. Our design consists of the coassembly of two dipeptide-chromophore conjugates, namely diphenylalanine (FF) dipeptide conveniently functionalized at the N-terminus with either a pyrene (Py-1, donor) or naphthalene diimide (NDI-1, acceptor). UV/Vis spectroscopy confirmed the formation of CT complexes. FTIR and 1 H NMR spectroscopy studies underlined the pivotal role of hydrogen bonding in the gelation process, and electronic paramagnetic resonance (EPR) measurements unraveled the advantage of preorganized CT supramolecular architectures for charge transport over solutions containing non-coassembled D and A molecular systems.

Translation and Cross-Cultural Adaptation with Preliminary Validation of GCOS-24 for Use in Spain.

The aim in this study was to translate and cross-culturally adapt the Genetic Counseling Outcome Scale (GCOS-24) for use in Spain and to carry out a preliminary psychometric validation in a sample of Spanish patients. With oversight by an expert panel, forward and backward translations were conducted to create the draft Spanish GCOS-24. Fourteen patients were recruited from a clinical genetics service in Madrid, Spain, to participate in cognitive interviews designed to explore readability and interpretability of the draft. Following qualitative analysis of interview transcripts, a final version of the Spanish GCOS-24 was agreed with the expert panel. No significant cross-cultural differences were identified. The Spanish GCOS-24 was then completed prior to and 2-4 weeks after genetic counseling by 59 patients attending the service, and data were analysed using analysis of variance. Preliminary psychometric validation of the Spanish GCOS-24 showed significantly higher GCOS-24 scores after genetic counseling (p < 0.0001), with good internal consistency (α = 0.84) and sensitivity to change over time, with a medium-to-large size effect (Cohen's d = 0.70). This compares well with the original English language GCOS-24. Findings demonstrate that the Spanish GCOS-24 has potential for use in evaluating clinical genetics services in Spain, but would benefit from assessment of test-retest reliability as well as structural and construct validity.

Familial aggregation of gastric cancer with microsatellite instability.

BACKGROUND: Microsatellite instability (MSI) is currently a new molecular subtype of gastric cancer (GC). About 90% of GC cases appear sporadically. MSI seems to be responsible for both sporadic and familial GC. The aim of this study was to analyze the frequency of MSI in GC with familial history of GC. METHODS: The MSI analysis was conducted using five quasi-monomorphic mononucleotide repeats: BAT-26, BAT-25, NR-24, NR-21 and NR-27. From our database, we analyzed 457 patients in terms of cancer history across family members, particularly focusing on GC. RESULTS: MSI status in patients without familial history of GC was present in 22.1% of the cases, whereas in the patients with familial history of GC it was present in 28% of the cases (p = 0.220). For 1st or 2nd degree family members with GC, MSI was observed in 27.6% and in 30.8%, respectively (p = 0.812). MSI was observed in hereditary gastric cancer (HGC) in 33.3% and in familial gastric cancer (FGC) in 30%. No difference in survival rates was observed between the analyzed groups. CONCLUSIONS: In our publication, we could not find any link between familial background and the MSI status in GC patients. More detailed molecular and genetic analysis of subgroups of these patients is required.

Incidence and Prognostic Value of Metastases to "Posterior" and Para-aortic Lymph Nodes in Resectable Gastric Cancer.

BACKGROUND: The purpose of this retrospective study was to evaluate the incidence and prognostic value of metastases to "posterior" (8p, 12b/p, 13) and para-aortic lymph nodes in a large cohort of Western patients submitted to D2 plus lymphadenectomy. METHODS: Removal of "posterior" nodes was performed in 743 patients, and para-aortic lymphadenectomy in a subgroup of 390 patients. After lymph node mapping and retrieval on the fresh specimen, a median number of 41 total lymph nodes were analyzed. The median follow-up period was 37 months for the entire series and 68 months for survivors. RESULTS: Of 743 included patients, 23 (3.1%) had metastases in station 8p, 12 (1.6%) in station 12b/p, and 19 (2.6%) in station 13. On the whole, 47 of 743 patients (6.3%) had positive "posterior" nodes. Para-aortic metastases were present in 42 of 390 patients (10.8%). Metastases to "posterior" stations were significantly related to depth of invasion, number of positive nodes, and surgical radicality. Distal tumors showed higher trend to metastasize to "posterior" nodes than upper third, whereas for para-aortic metastases it was the reverse. 5-year survival in patients with positivity to "posterior" nodes was 17%, with no significant difference according to 8p, 12b/p, and 13 stations; long-term outcome was overlapping to pN3b stage. 5-year survival in para-aortic positive cases was 11%, and a trend to better outcome was observed in proximal tumors. CONCLUSIONS: Although metastases to "posterior" and para-aortic nodes are expression of an advanced nodal stage, not negligible survival rates are observed in subgroups of patients.

Circulating levels and characterization of microparticles in patients with different degrees of glucose tolerance.

BACKGROUND: Microparticles (MPs) are vesicular structures shed from endothelial or circulating blood cells, after activation or apoptosis, and can be considered markers of vascular damage. We aimed to determine the levels of circulating MPs, their content of miRNA-126-3p and 5p, and their relationship with early endothelial activation/damage, in patients with different degree of glucose tolerance. METHODS: CD62E+, CD62P+, CD142+, CD45+ circulating MPs, their apoptotic (AnnexinV+) fractions, and miRNA-126 expression were determined in 39 prediabetic (PreDM), 68 type 2 diabetic (T2DM), and 53 control (NGT) subjects, along with main anthropometric and biochemical measurements. MPs were analysed by flow cytometry. miRNA-126 was measured by quantitative real-time PCR. Plasma antioxidant capacity was determined by electronic spin resonance; ICAM-1, and VCAM-1 by ELISA. RESULTS: Activated endothelial cell-derived MPs (CD62E+) were significantly increased in PreDM and T2DM in comparison to NGT (p < 0.0001). AnnexinV+/CD62E+ MPs and Annexin V+ MPs were significantly increased in T2DM compared to PreDM and NGT (p < 0.001); other MPs were not significantly different among groups. Plasma antioxidant capacity was significantly decreased in PreDM and T2DM compared to NGT (p = 0.001); VCAM-1 significantly increased in PreDM and T2DM in comparison to NGT (p = 0.001). miR-126-3p expression, but not miR-126-5p, in MPs, decreased significantly and progressively from NGT, to PreDM, and T2DM (p < 0.001). In PreDM and T2DM, CD62E+ MPs level was significantly and negatively associated with plasma glucose (p = 0.004). CONCLUSION: We show for the first time that circulating CD62E+ MPs level and miR-126-3p content in MPs are abnormal in subjects with pre-diabetes; the content of miR-126-3p correlates with markers of endothelial inflammation, such as VCAM-1, plasma antioxidant capacity, and microparticles, well-accepted markers of endothelial dysfunction.

Risk factor analysis for involvement of resection margins in gastric and esophagogastric junction cancer: an Italian multicenter study.

BACKGROUND: Resection margin (RM) involvement is associated with negative prognosis after gastrectomy. Intraoperative frozen section (IFS) analysis allows radical resection to be achieved in a single operation but is time-consuming and resource-consuming. The aim of this study was to assess risk factors associated with RM involvement to identify patients who would benefit from IFS analysis. METHODS: We retrospectively analyzed patients who underwent gastrectomy with curative intent for gastric or esophagogastric junction (EGJ) cancer from 2000 to 2014 in six Italian hospitals. RM status was assessed by IFS analysis and/or definitive histopathology examination. A set of 21 potential risk factors were compared in a multivariate analysis between patients with positive RMs on IFS analysis or definitive histopathology examination and a control cohort of similar patients with negative RMs, with the samples stratified into three subgroups (T1, T2-T4 Lauren intestinal pattern, T2-T4 Lauren diffuse/mixed pattern). RESULTS: One hundred forty-five patients had positive RMs. Survival was significantly worse in positive RM patients than in negative RM patients (89.5 months vs 28.9 months). Multivariate analysis showed that in T1 cancers a margin distance of less than 2 cm is a risk factor for RM involvement (odds ratio 15.7), in T2-T4 intestinal pattern cancers, serosa invasion (odds ratio 6.0), EGJ location (odds ratio 4.1), and a margin distance of less than 3 cm (odds ratio 4.0) are independent risk factors, and in T2-T4 diffuse/mixed pattern cancers, lymphatic infiltration (odds ratio 4.2), tumor diameter greater than 4 cm (odds ratio 3.5), EGJ location (odds ratio 2.8), and serosa invasion (odds ratio 2.2) are independent risk factors. CONCLUSIONS: Survival after gastrectomy is negatively affected by positive RMs. IFS analysis should be routinely used in patients with a high risk of positive RMs, especially in diffuse pattern cancers.

Probing photoinduced electron-transfer in graphene-dye hybrid materials for DSSC.

We investigated the photophysical properties of a newly synthesized hybrid material composed of a triphenylamine dye covalently bound to reduced graphene oxide, potentially relevant as a stable photosensitizer in dye-sensitized solar cells. The photophysical characterization has been carried out by means of fluorescence quenching and fluorescence lifetime measurements, complemented by Electron Paramagnetic Resonance (EPR) spectroscopy, aimed at the detailed description of the photoinduced processes occurring in the hybrid and in the mixed hybrid/N-doped TiO2 material. The combined optical/magnetic study unequivocally demonstrates a fast quenching of the dye excited state in the isolated hybrid and an efficient electron transfer to N-doped titania nanopowders. In the latter case, a metastable radical cation on the dye moiety is photogenerated and the corresponding negative charge, an electron, is trapped in defect sites of the doped semiconductor oxide. The spin distribution in the stable radical has been determined by EPR spectroscopy and correlated with DFT calculations.

Strong Prognostic Value of Microsatellite Instability in Intestinal Type Non-cardia Gastric Cancer.

BACKGROUND: The clinical role of microsatellite instability (MSI) in gastric cancer (GC) is controversial. A large series of patients submitted to respective surgery for primary GC with a long follow-up time was evaluated. METHODS: 472 patients with prospectively collected frozen samples of normal mucosa and tumor tissue stored in a biological tissue bank were included. Microsatellite analysis was evaluated using 5 quasi monomorphic mononucleotide repeats (BAT-26, BAT-25, NR-24, NR-21, and NR-27). The presence of MSI in 2 or more loci was classified as MSI-H, whereas all other cases were included in the microsatellite-stable (MSS) group. RESULTS: MSI-H phenotype was found in 111 of 472 patients (23.5%). MSI-H status was related significantly with older age, female gender, non-cardia location, WHO histotype, non-cardia Lauren intestinal type, and less advanced stages. Cancer-related 5-year survival was significantly higher in MSI-H versus MSS group (67.6% vs. 35%, p < 0.001). Stratified analysis revealed a significant impact of MSI on prognosis in non-cardia tumors of intestinal type or tubular/poorly differentiated histology, particularly in stages II and III; multivariate Cox regression analysis confirmed MSS status as a strong predictor of poor prognosis (hazard ratio 2.65, 95% CI 1.56-4.51, p < 0.001) in non-cardia intestinal type. No prognostic value of MSI in the diffuse-mixed type and signet-ring cell/mucinous histotypes was observed. CONCLUSIONS: MSI was confirmed as a significant predictor of long term outcome in a large series of GC with a long follow-up time, but the prognostic value is limited to selected histotypes of non-cardia tumors.

Monoclonal antibodies-based treatment in gastric cancer: current status and future perspectives.

Gastric cancer (GC) is the second leading cause of cancer-related death, and despite having improved treatment modalities over the last decade, for most patients, only modest improvements have been seen in overall survival. Recent progress in understanding the molecular biology of GC and the related signaling pathways offers, from the clinical point of view, promising advances for selected groups of patients. In the past, targeted therapies have significantly impacted the treatment strategy of several common solid tumors such as breast, colorectal, and lung cancers. Unfortunately, translational and clinical research shows fewer encouraging targeted treatments with regards to the GC. To date, only two monoclonal antibodies (mAb), named trastuzumab and ramucirumab, are approved for the treatment of advanced GC, suggesting that in GC, maybe more than in other cancers, effective targeted therapy requires patient selection based on precise predictive molecular biomarkers. The aim of this review is to summarize the available data on the clinical advantages offered by the use of mAbs in the treatment of advanced/metastatic GC. Future perspective is also discussed.

Boosting carbon quantum dots/fullerene electron transfer via surface group engineering.

The design of novel nanostructures with tailored opto-electronic properties is a crucial step for third-generation photovoltaics, and the development of cheap and environmentally compatible materials is still a challenge. Carbon quantum dots (CQDs) emerged as promising candidates but usually a low processability and poor electron-donor properties hampered their photovoltaic applications. We tackle these issues through the synthesis and photophysical characterization of N-doped CQDs functionalized with different thiophene-containing groups. Functionalization was aimed at enhancing the electron donating properties of the carbon dots and improving the solubility in nonpolar solvents. The increased solubility in organic solvents allowed us to investigate the photoinduced interactions of the functionalized carbon dots with the fullerene derivative PCBM in solution and in solid blends. The investigation was carried out by cyclic voltammetry, photoluminescence spectroscopy and electron paramagnetic resonance (EPR). The remarkable oxidation potential shift of the functionalized carbon dots with respect to the pristine materials and the HOMO-LUMO energies strongly suggest them as good electron donors towards PCBM. The electron transfer process between CQDs and PCBM resulted in efficient fluorescence quenching in solution and in total quenching in solid blends. By using EPR spectroscopy in the solid blends, we demonstrated the efficient electron transfer by observing the photoinduced formation of a PCBM radical anion in the presence of functionalized CQDs. Time-resolved EPR allowed us to identify differences in the charge transport efficiency for different CQD:PCBM blends. The enhanced processability of CQDs with PCBM and the promising charge-generation and separation properties pave the way to the development of "all-carbon" photovoltaic devices.

Evolution and emerging future of cytoreducxtive surgery and hyperthermic intraperitoneal chemoperfusion in gastric cancer: From treating the incurable to preventing recurrence.

The number of new gastric cancer (GC) cases is decreasing, and these patients have longer survival thanks to new oncological treatments. In advanced GC a common evolution of this neoplasm is peritoneal metastases (PM). In the past this finding meant no chance for cure. However, today, using high quality operations and HIPEC, we are able to increase the number of patients treated with curative intention. New options in the diagnosis of PM, tumour susceptibility for different drugs, importance of quality of life, usage in ascites treatment, diagnostic tools in image-guided surgery, new targeted therapies and analysis of currently ongoing trials are presented together with today's knowledge of HIPEC efficacy in order to evaluate gastric PM. HIPEC is an effective tool in the treatment of selected patients with PM from GC. Together with new diagnostic options such as targeted therapies, HIPEC may improve the prognosis of these patients, not only by treating clinically manifest carcinomatosis, but also in the prophylactic setting, addressing occult peritoneal seeding.

Malignant rhabdoid tumor of the small intestine in adults: a brief review of the literature and report of a case.

A malignant rhabdoid tumor was first described as a subtype of Wilms tumor in 1978. The most frequent location of these tumors is the kidney, and they are common in childhood. The extrarenal localization of these tumors has been described mainly in the central nervous system (called atypical teratoid-rhabdoid tumors), liver, soft tissues and colon. Localization in the small intestine is uncommon and since the 1990s, only a few cases of malignant rhabdoid tumors in the small intestine have been reported. This tumor is very aggressive and the prognosis is poor. We herein present our personal experience with a rhabdoid tumor of the jejunum in a 76-year-old male, and also provide an analysis of the cases of malignant rhabdoid tumor of the small intestine previously described in the literature as for a brief review. We also compared the previous reports and our present case to try to identify prognostic factors.

"Clinical significance of multifocal and multicentric breast cancers and choice of surgical treatment: a retrospective study on a series of 1158 cases".

BACKGROUND: The biological and clinical significance of multifocal and multicentric (MF/MC) breast cancers and the choice of appropriate surgical treatment for these tumors are still debated. METHODS: 1158 women operated on for a stage I-III breast cancer were included in this retrospective study; clinical and pathological data were obtained from the institutional database of the Department of Oncology of the University of Siena, Italy. The impact of MF/MC breast cancers on patterns of recurrence and breast cancer specific survival (BCSS) was investigated in relation to the type of surgical treatment. RESULTS: MF and MC cancers were present in 131 cases (11.3%) and 60 cases (5.2%) respectively and were more frequently treated with mastectomy (55 MF and 60 MC cancers, 81.2%) than with breast conserving surgery (36 MF cancers, 18.9%; p < 0.001). MF and MC breast cancers were associated with a worse prognosis with a BCSS of 154 months compared to 204 months of unicentric cancers (p < 0.001). In multivariate analysis, MF/MC cancers were independent prognostic factors for BCSS together with higher number of metastatic axillary nodes, absence of estrogen receptors and high proliferative activity. MF and MC cancers were related to a significantly shorter BCSS in patients submitted to mastectomy as well as those submitted to breast conserving surgery. Relapse at any site was higher in the subgroup of MF and MC cancers but the incidence of loco-regional and distant recurrences did not differ between patients treated with mastectomy or breast conserving surgery. CONCLUSIONS: Our results indicate that MF/MC cancers have a negative impact on prognosis and are related to higher loregional and distant relapse independently from the type of surgery performed. Adjuvant therapies did not modify the poorer outcome, but in patients receiving adjuvant anthacyclines, the differences with unicentric tumors were reduced. Our data support the hypothesis that MF/MC tumors may have a worse biological behavior and that the presence of multiple foci should be considered in planning adjuvant treatments.

Time resolved EPR of [70]fullerene monoadducts in the photoexcited triplet state.

Triplet excited states of isomers α, ß and γ of N-methyl-[70]fulleropyrrolidine in glassy toluene (T = 120 K) are investigated with Time Resolved EPR (TR-EPR) spectroscopy using pulsed laser photoexcitation. Both the zero field splitting (ZFS) parameters D, E and the anisotropic triplet population rates are measured. Results reveal a strong dependence of the triplet state wavefunction on the position (α, ß or γ) of the pyrrolidine addend with respect to the pole of the [70]fullerene unit. The relevant molecular orbitals have been calculated giving support to this finding. The dipolar tensor principal axes are located at the molecular reference frame from the inspection of the EPR spectra in a frozen liquid crystal (E7). Time evolution of the triplet EPR signals is different among the isomers, suggesting different triplet lifetimes and/or spin relaxation properties. The spin-density distribution in the first triplet state for N-methyl-[70]fulleropyrrolidine is compared with that previously observed for pristine C(70).

W-band transient EPR and photoinduced absorption on spin-labeled fullerene derivatives.

We investigated by W-band (94 GHz) transient electron paramagnetic resonance (TREPR) and photoinduced absorption (PIA) spectroscopy two fullerene derivatives bearing a nitroxide radical unit. After pulsed laser photoexcitation of the molecules in liquid toluene solution, complex EPR spectra are recorded, with lines in absorption and emission. The intrinsic higher spectral and temporal resolution of the W-band frequency leads to the assignment of all the lines in the spectrum and the determination of the sign and the absolute value of the exchange coupling between the fullerene in its photoexcited triplet state (S(T) = 1) and the radical (S(R) = 1/2). The two compounds with different fullerene-nitroxide spacers show opposite-ferromagnetic and antiferromagnetic-exchange couplings. The time evolution of the spectra and the polarization of the lines are interpreted in terms of several possible spin polarization mechanisms. The EPR measurements are complemented with PIA experiments.