Topology and regulation of the human eIF4A/4G/4H helicase complex in translation initiation.

The RNA helicase eIF4A plays a key role in unwinding of mRNA and scanning during translation initiation. Free eIF4A is a poor helicase and requires the accessory proteins eIF4G and eIF4H. However, the structure of the helicase complex and the mechanisms of stimulation of eIF4A activity have remained elusive. Here we report the topology of the eIF4A/4G/4H helicase complex, which is built from multiple experimentally observed domain-domain contacts. Remarkably, some of the interactions are continuously rearranged during the ATP binding/hydrolysis cycle of the helicase. We show that the accessory proteins modulate the affinity of eIF4A for ATP by interacting simultaneously with both helicase domains and promoting either the closed, ATP-bound conformation or the open, nucleotide-free conformation. The topology of the complex and the spatial arrangement of the RNA-binding surfaces offer insights into their roles in stimulation of helicase activity and the mechanisms of mRNA unwinding and scanning.

Locally recurrent rectal cancer: oncological outcomes with different treatment strategies in two tertiary referral units.

BACKGROUND: The optimal treatment for patients with locally recurrent rectal cancer (LRRC) is controversial. The aim of this study was to investigate different treatment strategies in two leading tertiary referral hospitals in Europe. METHODS: All patients who underwent curative surgery for LRRC between January 2003 and December 2017 in Catharina Hospital, Eindhoven, the Netherlands (CHE), or Karolinska University Hospital, Stockholm, Sweden (KAR), were studied retrospectively. Available MRIs were reviewed to obtain a uniform staging for optimal comparison of both cohorts. The main outcomes studied were overall survival (OS), local re-recurrence-free survival (LRFS), and metastasis-free survival (MFS). RESULTS: In total, 377 patients were included, of whom 126 and 251 patients came from KAR and CHE respectively. At 5 years, the LRFS rate was 62.3 per cent in KAR versus 42.3 per cent in CHE (P = 0.017), whereas OS and MFS were similar. A clear surgical resection margin (R0) was the strongest prognostic factor for survival, with a hazard ratio of 2.23 (95 per cent c.i. 1.74 to 2.86; P < 0.001), 3.96 (2.87 to 5.47; P < 0.001), and 2.00 (1.48 to 2.69; P < 0.001) for OS, LRFS, and MFS respectively. KAR performed more extensive operations, resulting in more R0 resections than in CHE (76.2 versus 61.4 per cent; P = 0.004), whereas CHE relied more on neoadjuvant treatment and intraoperative radiotherapy, to reduce the morbidity of multivisceral resections (P < 0.001). CONCLUSION: In radiotherapy-naive patients, neoadjuvant full-course chemoradiation confers the best oncological outcome. However, neoadjuvant therapy does not diminish the need for extended radical surgery to increase R0 resection rates.

Quantification and reduction of cross-vendor variation in multicenter DWI MR imaging: results of the Cancer Core Europe imaging task force.

OBJECTIVES: In the Cancer Core Europe Consortium (CCE), standardized biomarkers are required for therapy monitoring oncologic multicenter clinical trials. Multiparametric functional MRI and particularly diffusion-weighted MRI offer evident advantages for noninvasive characterization of tumor viability compared to CT and RECIST. A quantification of the inter- and intraindividual variation occurring in this setting using different hardware is missing. In this study, the MRI protocol including DWI was standardized and the residual variability of measurement parameters quantified. METHODS: Phantom and volunteer measurements (single-shot T2w and DW-EPI) were performed at the seven CCE sites using the MR hardware produced by three different vendors. Repeated measurements were performed at the sites and across the sites including a traveling volunteer, comparing qualitative and quantitative ROI-based results including an explorative radiomics analysis. RESULTS: For DWI/ADC phantom measurements using a central post-processing algorithm, the maximum deviation could be decreased to 2%. However, there is no significant difference compared to a decentralized ADC value calculation at the respective MRI devices. In volunteers, the measurement variation in 2 repeated scans did not exceed 11% for ADC and is below 20% for single-shot T2w in systematic liver ROIs. The measurement variation between sites amounted to 20% for ADC and < 25% for single-shot T2w. Explorative radiomics classification experiments yield better results for ADC than for single-shot T2w. CONCLUSION: Harmonization of MR acquisition and post-processing parameters results in acceptable standard deviations for MR/DW imaging. MRI could be the tool in oncologic multicenter trials to overcome the limitations of RECIST-based response evaluation. KEY POINTS: • Harmonizing acquisition parameters and post-processing homogenization, standardized protocols result in acceptable standard deviations for multicenter MR-DWI studies. • Total measurement variation does not to exceed 11% for ADC in repeated measurements in repeated MR acquisitions, and below 20% for an identical volunteer travelling between sites. • Radiomic classification experiments were able to identify stable features allowing for reliable discrimination of different physiological tissue samples, even when using heterogeneous imaging data.

Deep learning versus iterative image reconstruction algorithm for head CT in trauma.

PURPOSE: To compare the image quality between a deep learning-based image reconstruction algorithm (DLIR) and an adaptive statistical iterative reconstruction algorithm (ASiR-V) in noncontrast trauma head CT. METHODS: Head CT scans from 94 consecutive trauma patients were included. Images were reconstructed with ASiR-V 50% and the DLIR strengths: low (DLIR-L), medium (DLIR-M), and high (DLIR-H). The image quality was assessed quantitatively and qualitatively and compared between the different reconstruction algorithms. Inter-reader agreement was assessed by weighted kappa. RESULTS: DLIR-M and DLIR-H demonstrated lower image noise (p < 0.001 for all pairwise comparisons), higher SNR of up to 82.9% (p < 0.001), and higher CNR of up to 53.3% (p < 0.001) compared to ASiR-V. DLIR-H outperformed other DLIR strengths (p ranging from < 0.001 to 0.016). DLIR-M outperformed DLIR-L (p < 0.001) and ASiR-V (p < 0.001). The distribution of reader scores for DLIR-M and DLIR-H shifted towards higher scores compared to DLIR-L and ASiR-V. There was a tendency towards higher scores with increasing DLIR strengths. There were fewer non-diagnostic CT series for DLIR-M and DLIR-H compared to ASiR-V and DLIR-L. No images were graded as non-diagnostic for DLIR-H regarding intracranial hemorrhage. The inter-reader agreement was fair-good between the second most and the less experienced reader, poor-moderate between the most and the less experienced reader, and poor-fair between the most and the second most experienced reader. CONCLUSION: The image quality of trauma head CT series reconstructed with DLIR outperformed those reconstructed with ASiR-V. In particular, DLIR-M and DLIR-H demonstrated significantly improved image quality and fewer non-diagnostic images. The improvement in qualitative image quality was greater for the second most and the less experienced readers compared to the most experienced reader.

Lymphedema, serious adverse events, and imaging 1 year after comprehensive staging for endometrial cancer: results from the RASHEC trial.

BACKGROUND AND OBJECTIVES: In the Robot Assisted Surgery for High Risk Endometrial Cancer (RASHEC) trial, patients with high-risk endometrial cancer were randomly assigned to robot-assisted laparoscopic surgery (RALS) or laparotomy for pelvic and infrarenal para-aortic lymph node dissection. We here report on self-reported lower limb lymphedema (LLL), lymphocyst formation, ascites, and long-term serious adverse events 12 months after surgery. PATIENTS AND METHODS: Patients were enrolled between 2013 and 2016, and 96 patients were included in the per protocol analysis, evenly distributed between RALS and laparotomy. Self-reported LLL was recorded using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire for endometrial cancer-EN24, assessed before and 12 months after surgery. Computed tomography was assessed at baseline, 3, and 12 months. Medical charts were reviewed for serious adverse events and hospital admissions 31 to 365 days after surgery. RESULTS: At 12 months after laparotomy and RALS, 61% and 50% patients, respectively, reported LLL (p = 0.31). In univariate analysis, the mean score of LLL at 12 months was significantly higher for laparotomy than for RALS (p < 0.05) and for those without abdominal drainage (p = 0.02), but was not independently associated with LLL in the multivariate analysis. Imaging showed no significant difference in lymphocyst formation or ascites between surgical modalities. No difference was found in serious adverse events and admissions to hospital for any reason. There was no agreement between lymphocyst formation or ascites and self-reported LLL. CONCLUSION: Follow-up 1 year after comprehensive surgical staging for high-risk endometrial cancer showed no differences in self-reported LLL, findings on imaging, or SAE between laparotomy and robot-assisted surgery.

Immune gene expression and response to chemotherapy in advanced breast cancer.

BACKGROUND: Transcriptomic profiles have shown promise as predictors of response to neoadjuvant chemotherapy in breast cancer (BC). This study aimed to explore their predictive value in the advanced BC (ABC) setting. METHODS: In a Phase 3 trial of first-line chemotherapy in ABC, a fine needle aspiration biopsy (FNAB) was obtained at baseline. Intrinsic molecular subtypes and gene modules related to immune response, proliferation, oestrogen receptor (ER) signalling and recurring genetic alterations were analysed for association with objective response to chemotherapy. Gene-set enrichment analysis (GSEA) of responders vs non-responders was performed independently. Lymphocytes were enumerated in FNAB smears and the absolute abundance of immune cell types was calculated using the Microenvironment Cell Populations counter method. RESULTS: Gene expression data were available for 109 patients. Objective response to chemotherapy was statistically significantly associated with an immune module score (odds ratio (OR)=1.62; 95% confidence interval (CI), 1.03-2.64; P=0.04). Subgroup analysis showed that this association was restricted to patients with ER-positive or luminal tumours (OR=3.54; 95%, 1.43-10.86; P=0.012 and P for interaction=0.04). Gene-set enrichment analysis confirmed that in these subgroups, immune-related gene sets were enriched in responders. CONCLUSIONS: Immune-related transcriptional signatures may predict response to chemotherapy in ER-positive and luminal ABC.

Generation and Characterization of a Novel Small Biologic Alternative to Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) Antibodies, DS-9001a, Albumin Binding Domain-Fused Anticalin Protein.

Since it was recently reported that an antibody for proprotein convertase subtilisin/kexin type 9 (PCSK9) reduces the risk of cardiovascular events in a clinical context, PCSK9 inhibition is thought to be an attractive therapy for dyslipidemia. In the present study, we created a novel small biologic alternative to PCSK9 antibodies called DS-9001a, comprising an albumin binding domain fused to an artificial lipocalin mutein (ABD-fused Anticalin protein), which can be produced by a microbial production system. DS-9001a strongly interfered with PCSK9 binding to low-density-lipoprotein receptor (LDL-R) and PCSK9-mediated degradation of LDL-R. In cynomolgus monkeys, single DS-9001a administration significantly reduced the serum LDL-C level up to 21 days (62.4% reduction at the maximum). Moreover, DS-9001a reduced plasma non-high-density-lipoprotein cholesterol and oxidized LDL levels, and their further reductions were observed when atorvastatin and DS-9001a were administered in combination in human cholesteryl ester transfer protein/ApoB double transgenic mice. Additionally, their reductions on the combination of atorvastatin and DS-9001a were more pronounced than those on the combination of atorvastatin and anacetrapib. Besides its favorable pharmacologic profile, DS-9001a has a lower molecular weight (about 22 kDa), yielding a high stoichiometric drug concentration that might result in a smaller administration volume than that in existing antibody therapy. Since bacterial production systems are viewed as more suited to mass production at low cost, DS-9001a may provide a new therapeutic option to treat patients with dyslipidemia. In addition, considering the growing demand for antibody-like drugs, ABD-fused Anticalin proteins could represent a promising new class of small biologic molecules.

Long-term quality of life after comprehensive surgical staging of high-risk endometrial cancer - results from the RASHEC trial.

PURPOSE: The health-related quality of life (HRQoL) outcomes after comprehensive surgical staging including infrarenal paraaortic lymphadenectomy in women with high-risk endometrial cancer (EC) are unknown. Our aim was to investigate the long-term HRQoL between robot-assisted laparoscopic surgery (RALS) and laparotomy (LT). PATIENTS AND METHODS: A total of 120 women with high-risk stage I-II EC were randomised to RALS or LT for hysterectomy, bilateral salpingoophorectomy, pelvic and infrarenal paraaortic lymphadenectomy in the previously reported Robot-Assisted Surgery for High-Risk Endometrial Cancer trial. The HRQoL was measured with the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC-QLQ-30) and its supplementary questionnaire module for endometrial cancer (QLQ-EN24) questionnaire. Women were assessed before and 12 months after surgery. In addition, the EuroQol Eq5D non-disease specific questionnaire was used for descriptive analysis. RESULTS: There was no difference in the functional scales (including global health status) in the intention to treat analysis, though LT conferred a small clinically important difference (CID) over RALS in 'cognitive functioning' albeit not statistically significant -6 (95% CI-14 to 0, p = .06). LT conferred a significantly better outcome for the 'nausea and vomiting' item though it did not reach a CID, 4 (95% CI 1 to 7, p = .01). In the EORTC-QLQ/QLQ-EN24, no significant differences were observed. Eq5D-3L questionnaire demonstrated a higher proportion of women reporting any extent of mobility impairment 12 months after surgery in the LT arm (p = .03). CONCLUSION: Overall, laparotomy and robot-assisted surgery conferred similar HRQoL 12 months after comprehensive staging for high-risk EC.

Cardiophrenic lymph node resection in advanced ovarian cancer: surgical outcomes, pre- and postoperative imaging.

OBJECTIVE: To evaluate the accuracy of preoperative imaging in the diagnosis of cardiophrenic lymph node (CPLN) metastases and to report perioperative outcomes after resection of CPLN at the time of cytoreductive surgery for advanced epithelial ovarian cancer (EOC). Furthermore, to assess clearance of CPLN by postoperative imaging. METHODS: All women with stage IIIC/IV EOC subjected to surgery at our institution from January 2014 to October 2016 were retrospectively identified from a database. Among these, women subjected to CPLN resection during surgery were identified. Pre- and postoperative computed tomography (CT) scans, pathology reports, surgical approach and outcomes were reviewed. RESULTS: One hundred and eighty women with stage IIIC/IV EOC subjected to surgery with curative intent were identified. Twenty-four (13%) of these women underwent CPLN resection. All had CT imaging suggestive of CPLN metastases. 20/24 (83%) had confirmed metastases upon final pathology. CPLN resection was associated with longer operation time, more often advanced upper abdominal surgery and more postoperative complications but there was no difference in days from surgery to initiation of chemotherapy. Postoperative CT was still indicative of CPLN metastases in 13/22 (59%) women despite resection with confirmative pathology. CONCLUSIONS: Resection of CPLN metastases is highly feasible without considerable added morbidity. Concern regarding surgical clearance is raised since postoperative imaging was indicative of metastases in the majority of women. The prognostic significance of stage IV disease based exclusively on CPLN metastases is unclear and any survival benefit from the procedure is yet to be determined.

A randomized double-blind multi-center trial of hydrogen water for Parkinson's disease: protocol and baseline characteristics.

BACKGROUND: Our previous randomized double-blind study showed that drinking hydrogen (H2) water for 48 weeks significantly improved the total Unified Parkinson's Disease Rating Scale (UPDRS) score of Parkinson's disease (PD) patients treated with levodopa. We aim to confirm this result using a randomized double-blind placebo-controlled multi-center trial. METHODS: Changes in the total UPDRS scores from baseline to the 8(th), 24(th), 48(th), and 72(nd) weeks, and after the 8(th) week, will be evaluated. The primary endpoint of the efficacy of this treatment in PD is the change in the total UPDRS score from baseline to the 72(nd) week. The changes in UPDRS part II, UPDRS part III, each UPDRS score, PD Questionnaire-39 (PDQ-39), and the modified Hoehn and Yahr stage at these same time-points, as well as the duration until the protocol is finished because additional levodopa is required or until the disease progresses, will also be analyzed. Adverse events and screening laboratory studies will also be examined. Participants in the hydrogen water group will drink 1000 mL/day of H2 water, and those in the placebo water group will drink normal water. One-hundred-and-seventy-eight participants with PD (88 women, 90 men; mean age: 64.2 [SD 9.2] years, total UPDRS: 23.7 [11.8], with levodopa medication: 154 participants, without levodopa medication: 24 participants; daily levodopa dose: 344.1 [202.8] mg, total levodopa equivalent dose: 592.0 [317.6] mg) were enrolled in 14 hospitals and were randomized. DISCUSSION: This study will confirm whether H2 water can improve PD symptoms. TRIAL REGISTRATION: UMIN000010014 (February, 13, 2013).

Cotyledonoid dissecting leiomyoma of the uterus: report of two cases.

BACKGROUND: Cotyledonoid dissecting leiomyoma (Sternberg tumor) is a rare variant of the uterine smooth muscle tumor. Although this tumor is a benign tumor clinically and pathologically, the appearance and growth pattern is unusual, so it may be misdiagnosed as malignancy. CASE REPORTS: We report two cases of cotyledonoid dissecting leiomyoma of the uterus that occurred in two 44- and 31-year-old women, respectively. Total hysterectomy and bilateral salpingo-oophorectomy were performed in one of the patients, and myomectomy was done in the other one. Macroscopically, both tumors were grape-like exophytic masses resembling placental tissue. The patients were well after surgery, and one patient gave birth. To our knowledge, this is the first case report of a successful delivery after myomectomy of this tumor. CONCLUSION: To prevent aggressive surgery it is important to recognize that this tumor is a benign and unusual appearing variant of leiomyoma. A fertility-sparing surgical procedure should be considered if the patient wishes to preserve her fertility.

Initial magnetic resonance imaging tumour regression grade (mrTRG) as response evaluation after neoadjuvant treatment predicts sustained complete response in patients with rectal cancer.

PURPOSE: Reliable predictors of a sustained clinical complete tumour response (cCR) after neoadjuvant therapy in rectal cancer (RC) are lacking. The aim of this study was to determine if the tumour regression grade (TRG) assessed by magnetic resonance imaging (MRI), at the first restaging after neoadjuvant therapy can predict organ preservation, and to estimate the time interval after which surgery should be recommended in patients who remain in near cCR. MATERIALS AND METHODS: Eighty-three consecutive patients were assessed by MRI as having a cCR (mrTRG 1) or near cCR (mrTRG 2) after neoadjuvant therapy. Cox proportional hazards regression models and Kaplan-Meier survival analyses were used to determine associations between resection-free survival (RFS) and mrTRG at the first restaging, and in relation to mrTRG with a landmark period. mrTRG and pathological findings were compared in operated patients. RESULTS: mrTRG 2 at the first restaging significantly predicted poorer RFS during follow up. The best prediction of RFS was mrTRG at landmark 16 weeks after termination of radiotherapy; 42 out of 49 patients (86%) evaluated as mrTRG 1 had cCR at one year of follow up. In contrast, 12 out of 15 patients (80%) evaluated as mrTRG 2 had clinical signs of tumour and were recommended surgery. CONCLUSIONS: The first mrTRG, and to an even greater extent mrTRG at landmark 16 weeks predicts RFS. Patients who remain mrTRG 2 at 5-6 months after radiotherapy with signs of tumour should be recommended surgery. These findings may help in patient counselling and surgical decision-making.

PDCD4 inhibits translation initiation by binding to eIF4A using both its MA3 domains.

Programmed Cell Death 4 (PDCD4) is a protein known to bind eukaryotic initiation factor 4A (eIF4A), inhibit translation initiation, and act as a tumor suppressor. PDCD4 contains two C-terminal MA3 domains, which are thought to be responsible for its inhibitory function. Here, we analyze the structures and inhibitory functions of these two PDCD4 MA3 domains by x-ray crystallography, NMR, and surface plasmon resonance. We show that both MA3 domains are structurally and functionally very similar and bind specifically to the eIF4A N-terminal domain (eIF4A-NTD) using similar binding interfaces. We found that the PDCD4 MA3 domains compete with the eIF4G MA3 domain and RNA for eIF4A binding. Our data provide evidence that PDCD4 inhibits translation initiation by displacing eIF4G and RNA from eIF4A. The PDCD4 MA3 domains act synergistically to form a tighter and more stable complex with eIF4A, which explains the need for two tandem MA3 domains.

[Assessment of the cost of laparoscopy-assisted gastrectomy].

BACKGROUND: The cost of laparoscopic gastrectomy (LG) has not been fully clarified yet. PATIENTS AND METHODS: The actual cost for the instruments used for surgery was examined between LG and conventional open gastrectomy( OG) by separating distant (l D-) and total (l T-) gastrectomy in a total of 20 patients(5 for each)during Oct 2010 and Feb 2011. The profit was defined as the difference of the actual cost and the operation fee including the instruments determined by the insurance and compared. RESULTS: The fee for D-OG, T-OG, D-LG, and T-LG were 708, 700 yen, 856 , 400 yen, 783 , 600 yen and 922 , 300 yen, respectively. The mean profits of D-OG, T-OG, D-LG, and T-LG were 408 , 297 yen, 475 , 812 yen, 308, 681 yen and 269 , 478 yen, respectively. CONCLUSION: Appropriate surgical and instrumental fees should be determined considering the actual cost.

Magnetic resonance imaging as a predictor of surgical outcome in patients with local pelvic recurrence of colorectal cancer.

INTRODUCTION: Pelvic local recurrence of colorectal cancer (PRCRC) may be cured if radical surgery is performed. Preoperative assessment normally includes magnetic resonance imaging (MRI). The aim of this study was to evaluate the influence of specific MRI-related findings on outcome of surgery of PRCRC. MATERIALS AND METHODS: Clinical data from 95 consecutive patients, operated with a curative intent for PRCRC at Karolinska University Hospital during 2003-2013, were collected from medical records. Preoperative MRI examinations of the PRCRC were re-evaluated. The potential influence of clinical factors and specific MRI-findings (location, solid/mucinous, size, volume and border) on surgical resection margins (R0-R1) and survival were calculated with logistic and cox regression. RESULTS: Eighty-seven patients had available MRI scans and were included in the study. Sixty-five patients (75%) had a R0 resection and 22 patients (25%) had a R1 resection of their PRCRC. In all, 47 patients (54%) had an involved lateral compartment. Lateral location was the only MRI finding associated with both an increased risk of R1 resection (OR 3.97, 95%CI: 1.31-12.04) and death (HR 1.94, 95%CI: 1.07-3.51). Lateral location entailed an increased risk of death also after R0 resection (HR2.09, 95%CI: 1.07-4.10). Five-year survival was 35% for all patients, 44% after R0 resection and 7% after R1 resection. CONCLUSION: Tumour involvement of the lateral and posterior compartments on MRI was a predictor for R1 resection, but only lateral involvement was associated with an increased risk of death. An increased risk of death associated with lateral involvement was still present after R0 resection.

[20-25 procent of patients with rectal cancer may be saved from a rectal resection]. / Organsparande behandling vid rektalcancer ­ färre opereras.

Besides clinical evaluation, all patients with rectal cancer must be examined with CT of the chest and abdomen to assess the presence of metastases, pelvic MRI to stage the tumour locally, and if possible, colonoscopy to detect synchronous lesions. The recommended treatment is then discussed at an MDT conference and neoadjuvant radio- or chemoradiotherapy given according to national guidelines. A new digital rectal examination (DRE) and proctoscopy, CT and pelvic MRI should be performed around six weeks after treatment. The purpose is to detect potential new metastases and to assess tumour response after treatment. It is crucial to do a second MDT with careful MRI evaluation to detect a possible clinical complete response. If the post-treatment MRI shows a complete or near complete response, corresponding to clinical findings on DRE and endoscopy, the patient should be offered a prospective watch and wait protocol in a dedicated institution. With proper management of patients with rectal cancer, 20-25 procent may be saved from a rectal resection and the potential risk of a permanent stoma.

Pretreatment MRI in Primary Rectal Cancer as a Predictor for Oncological Outcomes After Surgery for Local Recurrence.

BACKGROUND/AIM: For patients with locally recurrent rectal cancer (LRRC) extensive surgery is often the only curative option and patient selection is crucial. This study aimed to investigate whether magnetic resonance imaging (MRI) characteristics of the primary tumour can predict oncological outcome after surgery for locally recurrent rectal cancer (LRRC). PATIENTS AND METHODS: All patients undergoing surgery for LRRC with a curative intent at the Karolinska University Hospital 2003-2013 were included. MRI examinations of the primary tumour were re-evaluated. RESULTS: In total, 54 patients were included. A tumour volume decrease of <70% after preoperative radiotherapy or chemoradiotherapy (C)RT for the primary tumour was correlated with a lower proportion of R0 resection of the LRRC (OR=0.07, 95% CI=0.01-0.84). No association between MRI characteristics of the primary tumour and prognosis after LRRC surgery was found. CONCLUSION: Long-term outcomes after surgery for LRRC were not significantly associated with MRI characteristics of the index tumour. However, factors associated with increased risk of R1 resection of LRRC were identified.

Stereoselective triplet-sensitised radical reactions of furanone derivatives.

The stereo- and regioselectivity of triplet-sensitised radical reactions of furanone derivatives have been investigated. Furanones 7a,b were excited to the (3)pipi* state by triplet energy transfer from acetone. Intramolecular hydrogen abstraction then occurred such that hydrogen was transferred from the tetrahydropyran to the beta position of the furanone moiety. Radical combination of the tetrahydropyranyl and the oxoallyl radicals led to the final products 8a,b. In the intramolecular reaction, overall, a pyranyl group adds to the alpha position of the furanone. The effect of conformation was first investigated with compounds 9a,b carrying an additional substituent on the tether between the furanone and pyranyl moiety. Further information on the effect of conformation and the relative configuration at the pyranyl anomeric centre and the furanone moiety was obtained from the transformations of the glucose derivatives 12, 14, 17 and 18. Radical abstraction occurred at the anomeric centre and at the 5'-position of the glucosyl moiety. Computational studies of the hydrogen-abstraction step were carried out with model structures. The activation barriers of this step for different stereoisomers and the abstraction at the anomeric centre and at the 6'-position of the tetrahydropyranyl moiety were calculated. The results of this investigation are in accordance with experimental observations. Furthermore, they reveal that the reactivity and regioselectivity are mainly determined in the hydrogen-abstraction step. Intramolecular hydrogen abstraction (almost simultaneous electron and proton transfer) in (3)pipi* excited furanones only takes place under restricted structural conditions in a limited number of conformations that are defined by the relative configuration of the substrates. It is observed that in the biradical intermediate, back-hydrogen transfer occurs leading to the starting compound. In the case of glucose derivatives, this reaction led to epimerisation at the anomeric centre.