GSURE criterion for unsupervised regularized reconstruction in tomographic diffractive microscopy

We propose an unsupervised regularized inversion method for reconstruction of the 3D refractive index map of a sample in tomographic diffractive microscopy. It is based on the minimization of the generalized Stein's unbiased risk estimator (GSURE) to automatically estimate optimal values for the hyperparameters of one or several regularization terms (sparsity, edge-preserving smoothness, total variation). We evaluate the performance of our approach on simulated and experimental limited-view data. Our results show that GSURE is an efficient criterion to find suitable regularization weights, which is a critical task, particularly in the context of reducing the amount of required data to allow faster yet efficient acquisitions and reconstructions.

The CONSTANCES Cohort Biobank: An Open Tool for Research in Epidemiology and Prevention of Diseases

“General-purpose cohorts” in epidemiology and public health are designed to cover a broad scope of determinants and outcomes, in order to answer several research questions, including those not defined at study inception. In this context, the general objective of the CONSTANCES project is to set up a large population-based cohort that will contribute to the development of epidemiological research by hosting ancillary projects on a wide range of scientific domains, and to provide public health information. CONSTANCES was designed as a randomly selected sample of French adults aged 18–69 years at study inception; 202,045 subjects were included over an 8-year period. At inclusion, the selected participants are invited to attend one of the 24 participating Health Prevention Centers (HPCs) for a comprehensive health examination. The follow-up includes a yearly self-administered questionnaire, and a periodic visit to an HPC. Procedures have been developed to use the national healthcare databases to allow identification and validation of diseases over the follow-up. The biological collection (serum, lithium heparinized plasma, EDTA plasma, urine and buffy coat) began gradually in June 2018. At the end of the inclusions, specimens from 83,000 donors will have been collected. Specimens are collected according to a standardized protocol, identical in all recruitment centers. All operations relating to bio-banking have been entrusted by Inserm to the Integrated Biobank of Luxembourg (IBBL). A quality management system has been put in place. Particular attention has been paid to the traceability of all operations. The nature of the biological samples stored has been deliberately limited due to the economic and organizational constraints of the inclusion centers. Some research works may require specific collection conditions, and can be developed on request for a limited number of subjects and in specially trained centers. The biological specimens that are collected will allow for a large spectrum of biomarkers studies and genetic and epigenetic markers through candidate or agnostic approaches. By linking the extensive data on personal, lifestyle, environmental, occupational and social factors with the biomarker data, the CONSTANCES cohort offers the opportunity to study the interplays between these factors using an integrative approach and state-of-the-art methods.

Maternal consumption of quinine-containing sodas may induce G6PD crises in breastfed children

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzyme defect often presenting with neonatal jaundice and/or hemolytic anemia. G6PD hemolytic events are linked with exposure to a pro-oxidant agent. We here report three cases of initial G6PD crises in breastfed children secondary to maternal consumption of a tonic drink which contains quinine. Quinine was found in breast milk of one of the mothers after she consumed tonic water.

CONCLUSION

The amount of quinine that is transmitted through breast milk appears to be sufficient to induce G6PD crises in breastfed children. We hence recommend that consumption of quinine-containing sodas during breastfeeding should be avoided in populations with a high prevalence of G6PD deficiency. What is Known: • G6PD hemolytic events are linked with exposure to a pro-oxidant agent. • Ingestion of fava beans by a mother who was breastfeeding has been reported to induce a neonatal G6PD crisis. What is New: • Maternal consumption of tonic drink which contains quinine appears to be sufficient to induce G6PD crises in breastfed children. • Maternal consumption of quinine-containing sodas during breastfeeding should be avoided in populations with a high prevalence of G6PD deficiency.

Risk Factors and Best Practices for the Prevention of Post-Cardiac Surgery Surgical Site Infections in a Tertiary Care Centre

BACKGROUND

Post-cardiac surgery surgical site infections (SSIs) pose devastating consequences in terms of morbidity and mortality to patients.

OBJECTIVE

To examine current risk factors and best practice perioperative care for prevention of SSI following cardiac surgery through the lens of the demographic/clinical characteristics of patients who developed post-cardiac surgery SSIs at a major tertiary care institution, and to identify where documentation is lacking and could be improved to better serve clinical practice.

METHODS

A literature review on post-cardiac surgery SSI prevention and risk factors was performed. These risk factors were examined through a retrospective chart review of the population of patients who developed SSIs during the study period.

RESULTS

The study population was characterized by a high prevalence of riskfactors including age, diabetes, obesity, operative time, blood glucose control, surgical re-exploration, blood transfusions, and emergency context, as well as differences from best practice guidelines such as preoperative showering. Compared to other populations in the literature, several ofthese risk factors were more prevalent at the study site than in the other comparable populations.

CONCLUSION

The patient population had a relatively high prevalence of riskfactors, and the care received by these patients varied in some ways from best practices. Using best practice guidelines, known risk factors, and the data specific to the institution can provide insightsfor analysis and practice improvement efforts in the form of identifying at-risk patients, improving adherence to best practice guidelines, targeting areas to focus care efforts, and improving clincal documentation.

Prevalence, risk factors and prognosis of hypernatraemia during hospitalisation in internal medicine

INTRODUCTION

Hypernatraemia in hospitalised patients is less common and less studied than hyponatraemia, although it also seems to be associated with a poor prognosis. The present study evaluates its prevalence, risk factors and prognosis in an internal medicine department.

METHODS

Full hospital stays over 28 months in a 36-bed internal medicine department were analysed retrospectively. Patients with at least one plasma sodium ≥ 150 mmol/l were compared first with all other patients and then individually with sex- and age-matched normonatraemic controls.

RESULTS

Plasma sodium ≥ 150 mmol÷l was observed during 49÷1945 hospitalisations (2.6%); it was acquired during hospitalisation in 30 cases (61%). Hypernatraemic patients were significantly older with no gender difference. They were comparable with their matched normonatraemic controls regarding the Charlson comorbidity index, although individual comorbidities varied. They were bedridden in 45% vs 15% for controls (p = 0.001). Nearly one-third of hypernatraemic patients had an increased extracellular fluid volume. Hypernatraemia was associated with higher in-hospital mortality (43% vs 2%, p < 0.001) and longer hospitalisation (median 21 vs 10 days, p = 0.004).

CONCLUSION

Hypernatraemia is more likely to occur in older and dependent patients and is associated with poor prognosis. Unlike classical teaching, it is often associated with increased extracellular fluid volume, even outside intensive care units.

Self-management support for peritoneal dialysis patients

The increasing prevalence of chronic illnesses and kidney disease, in particular, makes it necessary to adopt new approaches towards their management (Wagner, 1998). Evidence suggests that promoting self-management improves the health status of peritoneal dialysis (PD) patients, as they manage upwards of 90% of their own care. Patients who are unable to self-manage suffer from various complications. This project proposes an intervention aimed at improving self-management skills among PD patients.

GOAL

To promote self-management in peritoneal dialysis patients. This is achieved through the following objectives: (a) develop an algorithm that can improve patients' ability to solve the specific problem of fluid balance maintenance, (b) develop an educational session for patients on how to use the algorithm, and (c) develop an implementation strategy in collaboration with the PD nurse.

METHOD AND RESULTS

Three measures evaluate the effectiveness of the intervention. First, a telephone call log shows that participating patients call the clinic less to inquire about fluid balance maintenance. Next, a pre- and post-intervention knowledge test measures definite knowledge increase. Finally, a Patient Satisfaction Questionnaire reveals overall satisfaction with the intervention.

CONCLUSION

This project, which proved beneficial to our patient population, could be duplicated in other clinics. The algorithm "How do I choose a dialysis bag" and the slides of the educational sessions can be shared with PD nurses across the country for the benefit of PD patients.

Nuclear magnetic resonance and biochemical measurements of glucose utilization in the cone-dominant ground squirrel retina

PURPOSE

To provide quantitative information on glucose utilization in cone-dominant ground squirrel retinas.

METHODS

Ground squirrel eyecups were incubated in medium containing (14)C-glucose, and the production of (14)CO(2) was measured. Measurements were also made of lactic acid production (glycolysis). Nuclear magnetic resonance (NMR) was used to track metabolites generated from (13)C-1 glucose.

RESULTS

Ground squirrel eyecups produced lactate at a high rate and exhibited normal histology. Light-adaptation reduced glycolysis by 20%. Ouabain decreased glycolysis by 25% and decreased (14)CO(2) production by 60%. Blockade of glutamate receptors had little effect on the glycolysis and (14)CO(2) produced. When metabolic responses were restricted to photoreceptors, light caused a 33% decrease in (14)CO(2) production. The rate of (14)CO(2) production was less than 10% of lactate production. Lactate was the major product formed from (13)C-glucose. Other (13)C-labeled compounds included glutamate, aspartate, glutamine, alanine, taurine, and GABA. Lactate was the only product detected in the medium bathing the ground squirrel retinas. The rod-dominant rat retina exhibited a similar pattern of metabolites formed from glucose.

CONCLUSIONS

Lactate, not CO(2), is the major product of glucose metabolism in both ground squirrel and rat retinas. Active Na(+) transport, however, depends more on ATP produced by mitochondria than by glycolysis. A relatively high fraction of ATP production from glycolysis and glucose oxidation continues in the absence of active Na(+) pumping and glutamatergic transmission. Major neurotransmitters are synthesized from the aerobic metabolism of glucose; anoxia-induced impairment in retinal synaptic transmission may be due to depletion of neurotransmitters.

Stage III colon cancer prognosis prediction by gene expression profiling

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Background and Aims: Postoperative chemotherapy has become part of the standard treatment for stage III colon cancer patients. Since approximately half of patients are cured by surgery alone, adjuvant chemotherapy should not be used in all patients. This study aimed to assess the possibility to use microarray-based gene expression profiles to predict the prognosis of stage III colon cancer patients. Material and Methods: Forty-two patients operated on for a stage III colon cancer were included in this study. Twenty-one patients have received an adjuvant chemotherapy, while the other 21 have received no treatment. Twenty patients have developed a liver metastasis, while the other 22 have remained disease-free for at least 5 years. Tumor mRNA samples were profiled using the Affymetrix HGU133A GeneChip. Two analyses were performed: one with the 42 patients, the other with the 21 patients who did not receive any adjuvant chemotherapy. For each analysis, patients were repeatedly and randomly divided into 10,000 training (TS) and validation sets (VS) of 10 different sizes. For each TS/VS split, a 30-gene prognosis predictor (PP), identified on the TS, was used to predict the prognosis of VS patients. Performances of a 15-gene PP and a 34-gene PP, proposed by another research team, were also assessed on the same TS and VS. Results: First analysis (42 patients). The 10,000 30-gene PP yielded the following average prognosis prediction performance measures: 73.8% accuracy, 74.6% sensitivity, and 73.0% specificity. Improvements in prognosis prediction were observed with increasing TS size. A total of 4,446 genes were included in the 10,000 PP. The 15-gene PP yielded a 69.7% accuracy; the 34-gene PP yielded a 71.2% accuracy. Second analysis (21 patients). The 10,000 30-gene PP yielded the following average prognosis prediction performance measures: 77.7% accuracy, 75.8% sensitivity, and 79.9% specificity. Improvements in prognosis prediction were observed with increasing TS size. A total of 5,478 genes were included in the 10,000 PP. The 15-gene PP yielded a 78.5% accuracy; the 34-gene PP yielded a 81.9% accuracy. Conclusion: Microarray gene expression profiling is able to predict the prognosis of stage III colon cancer patients and, thus, might be used for an appropriate use of adjuvant chemotherapy.

No significant financial relationships to disclose.

Prognosis of stage II colon cancer by non-neoplastic mucosa gene expression profiling

We have assessed the possibility to build a prognosis predictor (PP), based on non-neoplastic mucosa microarray gene expression measures, for stage II colon cancer patients. Non-neoplastic colonic mucosa mRNA samples from 24 patients (10 with a metachronous metastasis, 14 with no recurrence) were profiled using the Affymetrix HGU133A GeneChip. Patients were repeatedly and randomly divided into 1000 training sets (TSs) of size 16 and validation sets (VS) of size 8. For each TS/VS split, a 70-gene PP, identified on the TS by selecting the 70 most differentially expressed genes and applying diagonal linear discriminant analysis, was used to predict the prognoses of VS patients. Mean prognosis prediction performances of the 70-gene PP were 81.8% for accuracy, 73.0% for sensitivity and 87.1% for specificity. Informative genes suggested branching signal-transduction pathways with possible extensive networks between individual pathways. They also included genes coding for proteins involved in immune surveillance. In conclusion, our study suggests that one can build an accurate PP for stage II colon cancer patients, based on non-neoplastic mucosa microarray gene expression measures.

Prognosis prediction of stage II colon cancer by gene expression profiling

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Background: The aims of the present study were: 1) to identify a prognosis signature (PS), based on microarray gene expression measures, in stage II colon cancer patients and to assess its accuracy with resampling techniques ; 2) to assess the accuracy, also with resampling techniques, of a previously proposed 23-gene PS. Methods: Colon tumor mRNA samples from 50 patients were profiled using the Affymetrix HGU133A GeneChip (22283 sequences). In a first part, the 50 patients were randomly divided into 2 groups (G1 and G2) of equal size that were considered alternately as training and validation sets. In a second part, the 50 patients were randomly divided into 1600 training (size=n) and validation (size=50-n) sets. Informative genes were selected on the training set by taking the 30 most differentially expressed genes between patients who recurred and those who remained disease-free; the accuracy of this PS was assessed by comparing the predicted prognosis (using a diagonal linear discriminant analysis (DLDA)) and the actual evolution for all the validation set patients. Using the same random splits, the accuracy of the 23-gene PS was assessed with a DLDA that used learning set patients as reference samples. Results: The 30-gene PS that was identified from G1 (G2) patients yielded a 80% (84%) prognosis prediction accuracy when applied on G2 (G1) patients. With resampling techniques, the prediction accuracy regularly increased with the learning set (LS) size: 65.5% (range=52.5–75%) with LS of size 10, and 82.7% (range=60–100%) with LS of size 40. Comparisons of compositions of the 100 PS for a given value of n suggested a high instability of informative genes; with LS of size 10, 7 genes were part of at least 10% of signatures; with LS of size 40, 7 genes were part of all the 100 signatures. The accuracy of the previously proposed 23-gene PS also increased with the learning set size. Conclusion: Microarray gene expression profiling represents a promising technique to predict the prognosis of stage II colon cancer patients. The present study also outlines the high instability of informative gene selection and suggests the usefulness of resampling techniques to obtain an honest assessment of prognosis prediction accuracy.

No significant financial relationships to disclose.

Reactivity towards singlet oxygen of propofol inside liposomes and neuronal cells

Singlet oxygen (1O2), a reactive oxygen species, has been found to be implicated in many cellular events and pathological disorders. Herein, we investigated the reactivity of 1O2 towards the anaesthetic agent propofol (PPF) encapsulated within DMPC liposomes. By time resolved luminescence, the rate constant of 1O2 quenching by PPF was evaluated, depending on the location of the sensitizer, with following values: 1.35+/-0.05x10(7) M(-1) s(-1) for deuteroporphyrin (as embedded source) and 0.8+/-0.04x10(7) M(-1) s(-1) for uroporphyrin (as external source), respectively. The nature of the oxidation product, resulting from the reaction of 1O2 with PPF, was determined using absorption and HPLC techniques. Finally, the in vitro protective effect of PPF towards the 1O2-induced neuronal cell toxicity was evaluated in terms of cell viability.

Création d’un questionnaire destiné à la prise en charge de la douleur dans les pathologies oculaires et/ou péri-oculaires : ODEON – Objectif Douleur En Ophtalmologie et Neuro-ophtalmologie

INTRODUCTION

Ophthalmologists contend with a wide range of painful acute and chronic diseases. However, there is no tool specific to ocular pain that aids the patient in describing and quantifying pain.

PURPOSE

Our objective was to develop a tool that would allow the ophthalmologist to identify the patient's pain quickly and precisely in order to measure its intensity and to determine possible causes.

METHODS

An interview guide was elaborated after a literature review. Structured interviews were conducted in hospitals by a clinical research associate with patients suffering from painful acute or chronic pathologies. Different types of quantification and description of pain were proposed to patients. A questionnaire was developed and tested. After the analysis of the tests, the ODEON pilot questionnaire (Objectif Douleur En Ophtalmologie et Neuro-ophtalmologie: target: ophthalmic and neuro-ophthalmic pain) was developed.

RESULTS

Twenty patients presenting ten different diagnoses were interviewed. Patients preferred to quantify pain with visual analogic or graduated scales. They appreciated the help of pictograms to describe their pain. Eight other patients presenting six different diagnoses tested the questionnaire. They judged the test version valid and easy to use, except for the section on emotional descriptors. An average of approximately 20 minutes was necessary to complete the questionnaire. After the tests, various questions were combined, reformulated, deleted or added. The ODEON pilot questionnaire contains five sections: 1. general health, 2. eyes and eyesight, 3. pain, 4. pain relief, 5. pictograms and sensorial descriptors. The closed- and open-ended questions included in these dimensions make it possible to measure patient pain and help the practitioner with patient management.

CONCLUSION

The ODEON pilot questionnaire was developed under the supervision of a pilot committee involving clinicians and methodologists. Patients have indicated acceptance of this self-administered questionnaire during the cognitive debriefing and it is now being validated.

[RT-PCR in clinical diagnosis]

Application fields of RT-PCR (reverse transcription-polymerase chain reaction) in clinical diagnosis comprises the assessment of viral load for RNA viruses and the analysis of gene transcription products. RT-PCR is also helpful when large genes have to be sequenced. Developments of quantitative approaches using real-time PCR recently led to a major widening of RT-PCR applications in clinical diagnosis. However, RT reaction is delicate due to its lack of reproducibility and to RNA lability and frequent contamination by DNA. In some cases additional difficulties come from the need to obtain a specific amplification in the presence of homologous sequences which might be present in higher amounts than the sequence of interest. These caveats have to be taken into account, when designing the RT protocol, and when choosing PCR primers and internal and/or external references. This review is aimed at helping the experimental setup of a RT-PCR based assay according to the objectives.