Absolute Metabolite Quantification Using Pure Shift NMR: Toward Quantitative Metabolic Profiling of Aqueous Biological Samples.

Accurate quantification of metabolites by nuclear magnetic resonance (NMR) is of prime importance in the field of health sciences for understanding the metabolic pathways of the investigated system, to address the mechanisms of action of diseases, and improving their diagnosis, treatment, and prognosis. Unfortunately, the absolute quantitative analysis of complex samples is still limited by sensitivity and resolution issues that are intrinsic to this technique. Ultrahigh-resolution pure shift methods have especially shown to be suitable for interpreting mixtures of metabolites in biological samples. Here, we introduce a robust analytical protocol based on the use of a pure shift library of calibration reference spectra to fit the fingerprint of each metabolite of interest and determine its concentration. The approach based on the SAPPHIRE pulse sequence enhanced with a block for solvent suppression has been validated through the results of a series of model mixtures, exhibiting excellent trueness (slope values in the range of 0.93-1.02) and linearity (R2 > 0.996) in a total time (a few hours) that is fully compatible with metabolomics studies. Furthermore, we have successfully applied our method to determine the absolute metabolite concentrations in a lymphoma extracellular medium, which improves metabolomic protocols reported to date by providing a quantitative and highly resolved vision of metabolic processes at play.

Monitoring Conformational Changes in an Enzyme Conversion Inhibitor Using Pure Shift Exchange NMR Spectroscopy.

We report the acquisition of 2D NMR EXSY spectra with ultrahigh resolution, which allows for probing the slow conformational exchange process in a pharmaceutical compound. The resolution enhancement is achieved by implementing interferogram based PSYCHE homonuclear decoupling to generate a pure shift proton spectrum along the direct domain of the resulting data. The performance of this pure shift EXSY pulse sequence is compared to the standard experiment recorded under identical conditions. It is found that although being less sensitive and requiring a longer acquisition time, the quality of pure shift spectra allows for extracting exchange rates values that are coherent with the ones determined by standard approach, on a temperature range that demonstrates the robustness of the chosen homonuclear decoupling method. The resolution enhancement provided by the simplification of proton line shape allows for probing a higher number of proton sites whose analysis would have been biased using a standard method. These results open the way to a thorough and accurate study of chemical exchange processes based on a multi-site analysis of 2D pure shift EXSY spectra.

Combining pure shift and J-edited spectroscopies: A strategy for extracting chemical shifts and scalar couplings from highly crowded proton spectra of oligomeric saccharides.

We report the application of pure shift and J-edited nuclear magnetic resonance spectroscopies to the structural analysis of a protected maltotrioside synthetic intermediate whose crowded 1 H spectrum displays highly crowded regions. The analytical strategy is based on the implementation of J-edited and TOCSY experiments whose resolution is optimized by the use of broadband homonuclear decoupling and selective refocusing techniques, to assign and measure chemical shifts and homonuclear scalar couplings with high accuracy. The resulting data show a high level of complementarity, providing a detailed insight into each subunit of this oligomeric saccharide, even for proton sites whose nuclear magnetic resonance signals strongly overlap. This approach allowed for fully assigning proton chemical shifts and extracting 80% of the 3 JHH couplings that are in excellent agreement with those expected for D-gluco-pyranosyl units in 4 C1 conformations.

Magnetic field dependence of spatial frequency encoding NMR as probed on an oligosaccharide.

The magnetic field dependence of spatial frequency encoding NMR techniques is addressed through a detailed analysis of (1)H NMR spectra acquired under spatial frequency encoding on an oligomeric saccharide sample. In particular, the influence of the strength of the static magnetic field on spectral and spatial resolutions that are key features of this method is investigated. For this purpose, we report the acquisition of correlation experiments implementing broadband homodecoupling or J-edited spin evolutions, and we discuss the resolution enhancements that are provided by these techniques at two different magnetic fields. We show that performing these experiments at higher field improves the performance of high resolution NMR techniques based on a spatial frequency encoding. The significant resolution enhancements observed on the correlation spectra acquired at very high field make them valuable analytical tools that are suitable for the assignment of (1)H chemical shifts and scalar couplings in molecules with highly crowded spectrum such as carbohydrates.

Prostate radiotherapy may cause fertility issues: a retrospective analysis of testicular dose following modern radiotherapy techniques.

BACKGROUND: Prostate cancer in younger men is rare but not exceptional. Radiotherapy is a cornerstone of prostate cancer treatment and yet, its impact on fertility is scarcely reported in literature. Given the radiosensitivity of testicular tissue, this study aimed to determine the testicular dose using modern radiotherapy techniques for definitive prostate irradiation. METHODS: One hundred radiotherapy plans were reviewed. Testicles were contoured retrospectively without dosimetric optimization on testicles. RESULTS: The median testicular dose was 0.58 Gy: 0.18 Gy in stereotactic plans, 0.62 Gy in Volumetric Modulated Arc Therapy plans and 1.50 Gy in Tomotherapy plans (p < 0.001). Pelvic nodal irradiation increased the median testicular dose to 1.18 Gy versus 0.26 Gy without nodal irradiation (p < 0.001). Weight and BMI were inversely associated with testicular dose (p < 0.005). 65% of patients reached the theoretical dose threshold for transient azoospermia, and 10% received more than 2 Gy, likely causing definitive azoospermia. CONCLUSION: Despite being probably lower than doses from older techniques, the testicular dose delivered with modern prostate radiotherapy is not negligible and is often underestimated because the contribution of daily repositioning imaging is not taken into account and most Treatment Planning Systems underestimate the out of field dose. Radiation oncologists should consider the impact on fertility and gonadal endocrine function, counseling men on sperm preservation if they wish to maintain fertility. TRIAL REGISTRATION: retrospectively registered.

Spontaneous resolution of intracranial hypertension following radiotherapy for posterior parasagittal meningioma: About two cases and review of the literature.

We report the cases of two patients who underwent normofractionated radiotherapy for evolutive asymptomatic parasagittal meningiomas. After completion of radiotherapy, both patients presented severe headache and vomiting episodes without papillar edema. We then decided a "wait-and-scan" strategy because of the slit-ventricles, and symptoms regressed spontaneously. MRI showed significant tumor regression a year after radiotherapy with a newly developed collateral venous drainage system in the first patient and a left, unusually large, superior anastomotic vein in the second. These clinical presentation and radiological evolution are compatible with venous stenosis caused by radiation-induced symptomatic edema, fading after the development of a collateral venous drainage system. The relation between pressure-related headaches and venous anatomy remains unclear in parasagittal meningiomas. These observations underline the importance of the study of venous anatomy when pressure-related headaches are suspected. Further clinical descriptions might help the clinicians to treat these patients' symptoms.

[Organ preservation for rectal cancer: What are the arguments in favor of radiotherapy?] / Préservation d'organe dans les cancers du rectum : quels arguments en faveur de la radiothérapie ?

Standard care for rectal cancers relies on both tumor (location relative to the sphincter, T and N stage, sphincter involvement) and patients characteristics. Radical surgery (total mesorectal excision) following short-course radiotherapy (RT) or standard chemo-radiotherapy, associated with induction or consolidation chemotherapy (total neoadjuvant treatment), remains the cornerstone of locally advanced rectal cancer (T3cd, T4 and/or N+) treatment. Nevertheless, for early stages, this radical resection could be avoided in favor of conservative approaches combining RT (external, contact, brachytherapy) with or without chemotherapy (concurrent, induction or consolidative), or even be limited, for good responders, to a local excision with view of organ-preservation strategies. This conservative approach could also be offered selectively to patients with complete clinical response after the induction sequence, irrespective of initial tumor characteristics. The Watch and Wait strategy relies on clinical, endoscopic and radiological evaluations, as well as sustained surveillance. Ongoing studies aim to improve response rates, either with chemotherapy intensification, or RT boost dose escalation with brachytherapy or contact-therapy.

[Stereotactic radiotherapy of non-tumoral brain pathologies: Arteriovenous malformations and trigeminal neuralgias]. / Radiothérapie stéréotaxique des affections cérébrales non tumorales : malformations artérioveineuses et névralgies trigéminales.

Stereotactic radiotherapy and radiosurgery allow delivery of high irradiation doses in a limited volume. These techniques are specially adapted to brain and nervous pathologies. Indication are not only cancers and tumors but also non tumor tissues such as arteriovenous malformations. In some case purpose of stereotactic radiotherapy is solely functional, for example for trigeminal neuralgia. We detail the questions that raise treatment of these non-tumor pathologies. These pathologies imply a multidisciplinary approach that associate radiation oncologists, neuro-radiologist and neurosurgeons.

Positron-emission tomography-guided radiation therapy: Ongoing projects and future hopes.

Radiation therapy has undergone significant advances these last decades, particularly thanks to technical improvements, computer science and a better ability to define the target volumes via morphological and functional imaging breakthroughs. Imaging contributes to all three stages of patient care in radiation oncology: before, during and after treatment. Before the treatment, the choice of optimal imaging type and, if necessary, the adequate functional tracer will allow a better definition of the volume target. During radiation therapy, image-guidance aims at locating the tumour target and tailoring the volume target to anatomical and tumoral variations. Imaging systems are now integrated with conventional accelerators, and newer accelerators have techniques allowing tumour tracking during the irradiation. More recently, MRI-guided systems have been developed, and are already active in a few French centres. Finally, after radiotherapy, imaging plays a major role in most patients' monitoring, and must take into account post-radiation tissue modification specificities. In this review, we will focus on the ongoing projects of nuclear imaging in oncology, and how they can help the radiation oncologist to better treat patients. To this end, a literature review including the terms "Radiotherapy", "Radiation Oncology" and "PET-CT" was performed in August 2019 on Medline and ClinicalTrials.gov. We chose to review successively these novelties organ-by-organ, focusing on the most promising advances. As a conclusion, the help of modern functional imaging thanks to a better definition and new specific radiopharmaceuticals tracers could allow even more precise treatments and enhanced surveillance. Finally, it could provide determinant information to artificial intelligence algorithms in "-omics" models.

Radiomics: A primer for the radiation oncologist.

PURPOSE: Radiomics are a set of methods used to leverage medical imaging and extract quantitative features that can characterize a patient's phenotype. All modalities can be used with several different software packages. Specific informatics methods can then be used to create meaningful predictive models. In this review, we will explain the major steps of a radiomics analysis pipeline and then present the studies published in the context of radiation therapy. METHODS: A literature review was performed on Medline using the search engine PubMed. The search strategy included the search terms "radiotherapy", "radiation oncology" and "radiomics". The search was conducted in July 2019 and reference lists of selected articles were hand searched for relevance to this review. RESULTS: A typical radiomics workflow always includes five steps: imaging and segmenting, data curation and preparation, feature extraction, exploration and selection and finally modeling. In radiation oncology, radiomics studies have been published to explore different clinical outcome in lung (n=5), head and neck (n=5), esophageal (n=3), rectal (n=3), pancreatic (n=2) cancer and brain metastases (n=2). The quality of these retrospective studies is heterogeneous and their results have not been translated to the clinic. CONCLUSION: Radiomics has a great potential to predict clinical outcome and better personalize treatment. But the field is still young and constantly evolving. Improvement in bias reduction techniques and multicenter studies will hopefully allow more robust and generalizable models.

[Protein profile in 45 Congolese children with sickle cell anaemia]. / Etude du profil protéique de 45 enfants drépanocytaires homozygotes congolais.

Sickle cell anemia (SCA) is a genetic disorder characterized by severe hemolytic anemia, frequent vaso-occlusive events and infections. In tropical environment, people are continuously in contact with infection agents. The present study was undertaken to measure 10 protein parameters in order to test humoral immunity, nutrition status and the relation between inflammation and hemolysis in sickle cell anemia patients in 45 Congolese sickle cell children (15 females and 30 males, median age: 7 yrs) and a control group of 43 well healthy congolese group (18 females, 25 males; median age 18 yrs). Mean values for immunoglobulins (IgG, IgM, IgA), nutrition proteins (albumin, transthyretin and transferrin) and inflammatory and hemolysis markers (C3, CRP, A1GP: alpha1-Glycoprotein acid and haptoglobin) were compared between two groups. Hyperstimulation of humoral immunity was observed in the SCA group. Most significative difference was found with IgA (p < 0,001). Intravascular hemolysis was illustrated by a significant decrease of the haptoglobin/A1GP ratio, and was constantly present in SCA patients. We also described a significative decrease (p < 0,001) of haptoglobin/A1GP ratio between SCA patients with inflammatory syndrom when compared to those without inflammation. All data confirm that haemolysis is quite linked to inflammation in SCA. In addition, nutrition parameters were significantly decreased in SCA group vs healthy congolese group.

Stereotactic radiotherapy in targeted therapy treated oligo-metastatic oncogene-addicted (non-small-cell) lung cancer.

While the prognosis of metastatic non-small-cell lung cancer has shown significant progress these last years, notably with the discovery of oncogen-driven subtypes and the development of targeted therapies, significant improvements are still needed. More recently, numerous authors studied the oligo-metastasis concept, where the metastasis are limited in number and sites involved, and that could benefit from an aggressive approach of these lesions, for instance with the help of stereotactic radiotherapy. Nevertheless, there is no clear consensus existing for the time being for the treatment of these tumors. Three main clinical situations can be distinguished: oligo-metastasis state de novo at diagnosis (synchronous) or as first metastatic event of an initially locally limited affection (metachronous); oligo-progression during systemic treatment of a pluri-metastatic disease; and finally oligo-persistence of some remaining metastatic lesions at the nadir of the systemic therapy effect. In this review, we will discuss the place of stereotactic radiotherapy in the treatment of non-small-cell oligo-metastatic oncogene-addicted cancers treated with targeted therapies, differentiating these three main clinical situations. In all these indications, this technique could provide a benefit in terms of local control, possibly even in specific survival, when associated with targeted therapy continuation, related to local control of the oligo-metastatic cerebral or extracerebral lesions.

Selective tissue distribution of carbonic anhydrase isozymes in the ox.

By affinity chromatography the isozymic distribution of carbonic anhydrase (carbonate hydro-lyase, EC 4.2.1.1) has been studied in extract from various bovine tissues. Carbonic anhydrase II forms isolated from erythrocyte, kidney and brain are indistinguishable by specific activity, amino acid composition, fingerprint, electrophoretic and immunological behaviour. By these criteria they differ from carbonic anhydrase I isolated from rumen epithelium.

Epilepsy, antiepileptic drugs, and malformations in children of women with epilepsy: a French prospective cohort study.

We conducted a prospective study of teratogenic effects of antiepileptic drugs (AEDs) in pregnant women with epilepsy in southeast France, comparing malformation rates with those collected by a birth defects registry. We evaluated isolated microcephalies separately. Malformations were seen in 7% of infants of mothers with epilepsy (IME) and in 1.36% of the general population. No significant relationship was found between type and severity of epilepsy and occurrence of malformations or isolated microcephaly. Valproate and phenytoin were the most teratogenic (all malformations). None of the malformations observed in IME whose mothers received valproate, phenytoin, or phenobarbital was seen in IME not exposed to the respective AEDs. Phenytoin plus phenobarbital was more teratogenic than phenobarbital alone. Benzodiazepines, prescribed only in combinations, had a borderline, nonspecific effect on microcephaly.

[Determination of alpha-1-foetoprotein in human serum by electroimmuno-diffusion on agarose (author's transl)]. / Dosage de l'alpha-1-foetoprotéine sérique par electroimmunodiffusion sur agarose

The electroimmunodiffusion on agarose has been applied for the determination of AFP in human serum. The proposed method can be used for concentrations between 0.6 and 50 mg/l; the reproducibility was judged to be acceptable. For concentrations higher than 10 mg/l, a good correlation was observed between electroimmunodiffusion and radial immunodiffusion.

[Understanding mistake-proofing]. / Comprendre la notion de détrompage.

The mistake-proofing concept often refers to physical devices that prevent actors from making a wrong action. In anaesthesiology, one immediately thinks to specific design of outlets for medical gases. More generally, the principle of mistake-proofing is to avoid an error, by placing knowledge in the world rather than knowledge in the head. As it often happens in risk management, healthcare has received information transfers from the industry. Computer is changing the concept of mistake-proofing, initially based on physical design, such as aerospace and automotive industry. The mistake-proofing concept may be applied to prevention, detection, and mitigation of errors. The forcing functions are a specific part of mistake-proofing: they prevent a wrong action or they force a virtuous one. Grout proposes a little shortcut to identify mistake-proofing devices: "If it is not possible to picture it in action, it is probably not a mistake-proofing device".