[Strategy for the practice of digestive and oncologic surgery in COVID-19 epidemic situation]. / Stratégie pour la pratique de la chirurgie digestive et oncologique en situation d'épidémie de COVID-19.

The COVID-19 pandemic is changing the organization of healthcare and has a direct impact on digestive surgery. Healthcare priorities and circuits are being modified. Emergency surgery is still a priority. Functional surgery is to be deferred. Laparoscopic surgery must follow strict rules so as not to expose healthcare professionals (HCPs) to added risk. The question looms large in cancer surgery - go ahead or defer? There is probably an added risk due to the pandemic that must be balanced against the risk incurred by deferring surgery. For each type of cancer - colon, pancreas, oesogastric, hepatocellular carcinoma - morbidity and mortality rates are stated and compared with the oncological risk incurred by deferring surgery and/or the tumour doubling time. Strategies can be proposed based on this comparison. For colonic cancers T1-2, N0, it is advisable to defer surgery. For advanced colonic lesions, it seems judicious to undertake neoadjuvant chemotherapy and then wait. For rectal cancers T3-4 and /or N+, chemoradiotherapy is indicated, short radiotherapy must be discussed (followed by a waiting period) to reduce time of exposure in the hospital and to prevent infections. Most complex surgery with high morbidity and mortality - oesogastric, hepatic or pancreatic - is most often best deferred.

Strategy for the practice of digestive and oncological surgery during the Covid-19 epidemic.

The Covid-19 pandemic is changing the organization of healthcare and has a direct impact on digestive surgery. Healthcare priorities and circuits are being modified. Emergency surgery is still a priority. Functional surgery is to be deferred. Laparoscopic surgery must follow strict rules so as not to expose healthcare professionals (HCPs) to added risk. The question looms large in cancer surgery-go ahead or defer? There is probably an added risk due to the pandemic that must be balanced against the risk incurred by deferring surgery. For each type of cancer-colon, pancreas, oesogastric, hepatocellular carcinoma-morbidity and mortality rates are stated and compared with the oncological risk incurred by deferring surgery and/or the tumour doubling time. Strategies can be proposed based on this comparison. For colonic cancers T1-2, N0, it is advisable to defer surgery. For advanced colonic lesions, it seems judicious to undertake neoadjuvant chemotherapy and then wait. For rectal cancers T3-4 and/or N+, chemoradiotherapy is indicated, short radiotherapy must be discussed (followed by a waiting period) to reduce time of exposure in the hospital and to prevent infections. Most complex surgery with high morbidity and mortality-oesogastric, hepatic or pancreatic-is most often best deferred.

Geriatric analysis from PRODIGE 20 randomized phase II trial evaluating bevacizumab + chemotherapy versus chemotherapy alone in older patients with untreated metastatic colorectal cancer.

BACKGROUND: Older patients have frailty characteristics that impair the transposition of treatment results found in younger patients. Predictive factors are needed to help with treatment choices for older patients. The PRODIGE 20 study is a randomized phase II study that evaluated chemotherapy associated with bevacizumab (BEV) or not (CT) in patients aged 75 years or older. PATIENTS AND METHODS: Patients underwent a geriatric assessment at randomization and at each evaluation. The predictive value of geriatric and oncologic factors was determined for the primary composite end-point assessing safety and efficacy of treatment (BEV or CT) simultaneously and also progression-free survival (PFS) and overall survival (OS). RESULTS: 102 patients were randomized (51 BEV and 51 CT; median age 80 years [range 75-91]). On multivariate analysis, baseline normal independent activity of daily living (IADL) score and no previous cardiovascular disease predicted the primary end-point. High (versus low) baseline Köhne score predicted short PFS and baseline Spitzer quality of life (QoL) score <8, albumin level ≤35 g/L, CA19.9 >2 LN levels above normal and high baseline Köhne score predicted short OS. Survival without deteriorated QoL and autonomy was similar with BEV and CT. On subgroup analyses, the benefit of bevacizumab seemed to be maintained in patients with baseline impaired IADL or nutritional status. CONCLUSION: Normal IADL score was associated with a good efficacy and safety of both BEV and CT. Köhne criteria may be relevant prognostic factors in older patients. Adding bevacizumab to chemotherapy does not impair patient autonomy or QoL.

Bevacizumab+chemotherapy versus chemotherapy alone in elderly patients with untreated metastatic colorectal cancer: a randomized phase II trial-PRODIGE 20 study results.

Background: Metastatic colorectal cancer frequently occurs in elderly patients. Bevacizumab in combination with front line chemotherapy (CT) is a standard treatment but some concern raised about tolerance of bevacizumab for these patients. The purpose of PRODIGE 20 was to evaluate tolerance and efficacy of bevacizumab according to specific end points in this population. Patients and methods: Patients aged 75 years and over were randomly assigned to bevacizumab + CT (BEV) versus CT. LV5FU2, FOLFOX and FOLFIRI regimen were prescribed according to investigator's choice. The composite co-primary end point, assessed 4 months after randomization, was based on efficacy (tumor control and absence of decrease of the Spitzer QoL index) and safety (absence of severe cardiovascular toxicities and unexpected hospitalization). For each arm, the treatment will be consider as inefficient if 20% or less of the patients met the efficacy criteria and not safe if 40% or less met the safety criteria. Results: About 102 patients were randomized (51 BEV and 51 CT), median age was 80 years (range 75-91). Primary end point was met for efficacy in 50% and 58% and for safety in 61% and 71% of patients in BEV and CT, respectively. Median progression-free survival was 9.7 months in BEV and 7.8 months in CT. Median overall survival was 21.7 months in BEV and 19.8 months in CT. The 36-month overall survival rate was 27% in BEV and 10.1% in CT. Severe toxicities grade 3/4 were mainly non-hematologic toxicities (80.4% in BEV, 63.3% in CT). Conclusion: Bevacizumab combined with CT was safe and efficient. Both arms met the primary safety and efficacy criteria.

[Optic nerve hypoplasia and septo-optic dysplasia]. / Optikushypoplasie und septooptische Dysplasie.

Optic nerve hypoplasia (ONH) is one of the most common causes of congenital visual impairment. It was first described in 1915 and represents a developmental disorder of the central nervous system. It is often associated with intracranial midline defects and is then referred to as septo-optic dysplasia (SOD). The symptoms of ONH range from minimal visual dysfunction to significant visual impairment with sensory defect nystagmus and even blindness. The ONH is often associated with further systemic, endocrinological and neurological abnormalities requiring a close interdisciplinary treatment of the patients.

Effect of adipose tissue volume loss on circulating 25-hydroxyvitamin D levels: results from a 1-year lifestyle intervention in viscerally obese men.

BACKGROUND/OBJECTIVES: Although weight loss has been associated with changes in circulating 25-hydroxyvitamin D (25(OH)D) levels, the quantification of the increase in 25(OH)D levels as a function of adipose tissue volume loss precisely assessed by imaging has not been reported before. The objective of this substudy was to describe the effects of a 1-year lifestyle intervention on plasma 25(OH)D levels. The relationships between changes in 25(OH)D levels and changes in adiposity volume (total and by adipose tissue compartment) were studied. SUBJECTS/METHODS: This intervention study was performed between 2004 and 2006 and participants were recruited from the general community. Sedentary, abdominally obese and dyslipidemic men (n=103) were involved in a 1-year lifestyle modification program. Subjects were individually counseled by a kinesiologist and a nutritionist once every 2 weeks during the first 4 months with subsequent monthly visits in order to elicit a 500-kcal daily energy deficit and to increase physical activity/exercise habits. Body weight, body composition and fat distribution were assessed by dual-energy X-ray absorptiometry and computed tomography, whereas the 25(OH)D levels were measured with an automated assay. RESULTS: The 1-year intervention resulted in a 26% increase in circulating 25(OH)D (from 48±2 nmol l(-1) or 19±0.8 ng ml(-1) (±s.e.m.) to 58±2 nmol l(-1) or 23±0.8 ng ml(-1), P<0.0001) along with a 26% decrease in visceral adiposity volume (from 1947±458 to 1459±532 cm3). One-year increases in 25(OH)D levels correlated inversely with changes in all adiposity indices, especially Δvisceral (r=-0.36, P<0.0005) and Δtotal abdominal (r=-0.37, P<0.0005) adipose tissue volumes. CONCLUSIONS: These results indicate that there is a linear increase in circulating 25(OH)D levels as a function of adiposity volume loss, and therefore suggest a role of adiposity reduction in the management of obesity-associated vitamin D insufficiency.

Fully versus partially covered self-expandable metal stents in benign esophageal strictures.

Self-expandable plastic stents are currently recommended for refractory benign esophageal strictures but they show disappointing results in terms of migration and long-term efficacy. We report here our experience in the management of benign esophageal strictures with partially covered (PCSEMS) and fully covered self-expandable metal stents (FCSEMS). We performed a retrospective analysis of self-expandable metal stent (SEMS) placements for benign esophageal strictures from 1998 to 2011 in Rouen University Hospital. Twenty-two patients (15 men, 7 women) attempted 40 esophageal SEMS placements (17 PCSEMS, 23 FCSEMS) during this period. All technical complications were migrations. Migration was noted after 3/17 PCSEMS (17.6%) and 4/23 FCSEMS placement (17.4%, P = ns). Clinical complications occurred after 6/17 PCSEMS and 2/23 FCSEMS placements (35.3% vs. 8.7%, P = 0.053). PCSEMS caused two major complications (fistulae) whereas FCSEMS did not cause any major complication (11.7% vs. 0%). Mean dysphagia score was significantly lower after SEMS placement (1.68 vs. 3.08, P < 0.001) with similar results for PCSEMS and FCSEMS. Stent placement resulted in long-term clinical success for 23.5% of PCSEMS and 34.7% of FCSEMS (P = 0.0505). FCSEMS provide satisfying clinical success rate with an acceptable complication rate and they could constitute a relevant therapeutic option in the management of benign esophageal strictures.

TP53 mutations predict disease control in metastatic colorectal cancer treated with cetuximab-based chemotherapy.

Recent studies have suggested that activation of the EGFR pathway leads to malignant transformation only if the p53 protein is inactivated. Therefore, we evaluated the impact of TP53 mutations on cetuximab-based chemotherapy (CT) sensitivity in combination with KRAS mutations that have been associated with cetuximab resistance. KRAS and TP53 status were assessed in tumours from 64 metastatic colorectal cancer patients treated with cetuximab-based CT and correlated to clinical response using the Fisher's exact test. Times to progression (TTPs) according to gene status were calculated using the Kaplan-Meier method and compared with log-rank test. TP53 mutations were found in 41 patients and were significantly associated with controlled disease (CD), as defined as complete response, partial response or stable disease (P=0.037) and higher TTP (20 vs 12 weeks, P=0.004). Remarkably, in the subgroup of 46 patients without KRAS mutation, but not in patients with KRAS mutation, TP53 mutations were also associated with CD (P=0.008) and higher TTP (24 vs 12 weeks, P=0.0007). This study suggests that TP53 mutations are predictive of cetuximab sensitivity, particularly in patients without KRAS mutation, and that TP53 genotyping could have a clinical interest to select patients who should benefit from cetuximab-based CT.

Structure of the human 3alpha-hydroxysteroid dehydrogenase type 3 in complex with testosterone and NADP at 1.25-A resolution.

The first crystallographic structure of human type 3 3alpha-hydroxysteroid dehydrogenase (3alpha-HSD3, AKR1C2), an enzyme playing a critical role in steroid hormone metabolism, has been determined in complex with testosterone and NADP at 1.25-A resolution. The enzyme's 17beta-HSD activity was studied in comparison with its 3alpha-HSD activity. The enzyme catalyzes the inactivation of dihydrotestosterone into 5alpha-androstane-3alpha,17beta-diol (3alpha-diol) as well as the transformation of androstenedione into testosterone. Using our homogeneous and highly active enzyme preparation, we have obtained 150-fold higher 3alpha-HSD specificity as compared with the former reports in the literature. Although the rat and the human 3alpha-HSDs share 81% sequence homology, our structure reveals significantly different geometries of the active sites. Substitution of the Ser(222) by a histidine in the human enzyme may compel the steroid to adopt a different binding to that previously described for the rat (Bennett, M. J., Albert, R. H., Jez, J. M., Ma, H., Penning, T. M., and Lewis, M. (1997) Structure 5, 799-T812). Furthermore, we showed that the affinity for the cofactor is higher in the human 3alpha-HSD3 than the rat enzyme due to the presence of additional hydrogen bonds on the adenine moiety and that the cofactor is present under its reduced form in the active site in our preparation.

Monocharged inhibitors of mast cell tryptase derived from potent and selective dibasic inhibitors.

Truncation of potent and selective dibasic inhibitors afforded monocharged inhibitors of human mast-cell tryptase. Using two classes of analogues as lead structures, several monocharged derivatives were identified with K(i) values ranging from 0.084 to 0.21 microM against the enzyme.

Dibasic inhibitors of human mast cell tryptase. Part 3: identification of a series of potent and selective inhibitors containing the benzamidine functionality.

A survey of charged groups and linkers for a series of symmetrical and unsymmetrical dibasic inhibitors is described, leading to several classes of potent and selective inhibitors. In particular, the benzamidine functionality was identified as the most potent charged group investigated.

Human oestrogenic 17beta-hydroxysteroid dehydrogenase specificity: enzyme regulation through an NADPH-dependent substrate inhibition towards the highly specific oestrone reduction.

Human oestrogenic 17beta-hydroxysteroid dehydrogenase (17beta-HSD1) catalyses the final step in the biosynthesis of all active oestrogens. Here we report the steady-state kinetics for 17beta-HSD1 at 37 degrees C and pH 7.5, using a homogeneous enzyme preparation with oestrone, dehydroepiandrosterone (DHEA) or dihydrotestosterone (DHT) as substrate and NADP(H) as the cofactor. Kinetic studies made over a wide range of oestrone concentrations (10 nM-10 microM) revealed a typical substrate-inhibition phenomenon. Data analysis using the substrate-inhibition equation v=V.[s]/[K(m)+[s](1+[s]/K(i))] gave a K(m) of 0.07+/-0.01 microM, a k(cat) (for the dimer) of 1.5+/-0.1 s(-1), a specificity of 21 microM(-1) x s(-1) and a K(i) of 1.3 microM. When NADH was used instead of NADPH, substrate inhibition was no longer observed and the kinetic constants were significantly modified to 0.42+/-0.07 microM for the K(m), 0.8+/-0.04 s(-1) for the k(cat) and 1.9 microM(-1) x s(-1) for the specificity. The modification of an amino acid in the cofactor-binding site (Leu36Asp) eliminated the substrate inhibition observed in the presence of NADPH, confirming the NADPH-dependence of the phenomenon. The possible formation of an enzyme-NADP(+)-oestrone dead-end complex during the substrate-inhibition process is supported by the competitive inhibition of oestradiol oxidation by oestrone. Kinetic studies performed with either DHEA (K(m)=24+/-4 microM; k(cat)=0.47+/-0.06 s(-1); specificity=0.002 microM(-1) x s(-1)) or DHT (K(m)=26+/-6 microM; k(cat)=0.2+/-0.02 s(-1); specificity=0.0008 microM(-1) x s(-1)) in the presence of NADP(H) resulted in low specificities and no substrate inhibition. Taken together, our results demonstrate that the high specificity of 17beta-HSD1 towards oestrone is coupled with an NADPH-dependent substrate inhibition, suggesting that both the specificity and the enzyme control are provided for the cognate substrate.

Dibasic inhibitors of human mast cell tryptase. Part 1: synthesis and optimization of a novel class of inhibitors.

The synthesis and optimization of a novel class of reversible and active-site directed dibasic inhibitors of human mast cell tryptase are described. The compounds were shown to be both remarkably potent and selective for tryptase with Ki values for optimized inhibitors in the picomolar range.

Dibasic inhibitors of human mast cell tryptase. Part 2: structure-activity relationships and requirements for potent activity.

Detailed structure activity relationships (SARs) for a series of dibasic human tryptase inhibitors are presented. The structural requirements for potent inhibitory activity are remarkably broad with a range of core template modifications being well tolerated. Optimized inhibitors demonstrate potent anti-asthmatic activity in a sheep model of allergic asthma. APC-2059, a dibasic tryptase inhibitor with subnanomolar activity, has been advanced to phase II clinical trials for the treatment of both psoriasis and ulcerative colitis.

Dehydroepiandrosterone and dihydrotestosterone recognition by human estrogenic 17beta-hydroxysteroid dehydrogenase. C-18/c-19 steroid discrimination and enzyme-induced strain.

Steroid hormones share a very similar structure, but they behave distinctly. We present structures of human estrogenic 17beta-hydroxysteroid dehydrogenase (17beta-HSD1) complexes with dehydroepiandrosterone (DHEA) and dihydrotestosterone (DHT), providing the first pictures to date of DHEA and DHT bound to a protein. Comparisons of these structures with that of the enzyme complexed with the most potent estrogen, estradiol, revealed the structural basis and general model for sex hormone recognition and discrimination. Although the binding cavity is almost entirely composed of hydrophobic residues that can make only nonspecific interactions, the arrangement of residues is highly complementary to that of the estrogenic substrate. Relatively small changes in the shape of the steroid hormone can significantly affect the binding affinity and specificity. The K(m) of estrone is more than 1000-fold lower than that of DHEA and the K(m) of estradiol is about 10 times lower than that of DHT. The structures suggest that Leu-149 is the primary contributor to the discrimination of C-19 steroids and estrogens by 17beta-HSD1. The critical role of Leu-149 has been well confirmed by site-directed mutagenesis experiments, as the Leu-149 --> Val variant showed a significantly decreased K(m) for C-19 steroids while losing discrimination between estrogens and C-19 steroids. The electron density of DHEA also revealed a distortion of its 17-ketone toward a beta-oriented form, which approaches the transition-state conformation for DHEA reduction.

3D-structure of human estrogenic 17beta-HSD1: binding with various steroids.

Human estrogenic dehydrogenase (17beta-HSD1) catalyses the last step in the biosynthesis of the active estrogens that stimulate the proliferation of breast cancer cells. While the primary substrate for the enzyme is estrone, the enzyme has some activity for the non-estrogenic substrates. To better understand the structure function relationships of 17beta-HSD1 and to provide a better ground for the design of inhibitors, we have determined the crystal structures of 17beta-HSD1 in complex with different steroids. The structure of the complex of estradiol with the enzyme determined previously (Azzi et al., Nature Structural Biology 3, 665-668) showed that the narrow active site was highly complementary to the substrate. The substrate specificity is due to a combination of hydrogen bonding and hydrophobic interactions between the steroid and the enzyme binding pocket. We have now determined structures of 17beta-HSD1 in complex with dihydrotestosterone and 20alpha-OH-progesterone. In the case of the C19 androgen, several residues within the enzyme active site make some small adjustments to accommodate the increased bulk of the substrate. In addition, the C19 steroids bind in a slightly different position from estradiol with shifts in positions of up to 1.4 A. The altered binding position avoids unfavorable steric interactions between Leu 149 and the C19 methyl group (Han et al., unpublished). The known kinetic parameters for these substrates can be rationalized in light of the structures presented. These results give evidence for the structural basis of steroid recognition by 17beta-HSD1 and throw light on the design of new inhibitors for this pivotal steroid enzyme.