In situ uniaxial pressure cell for x-ray and neutron scattering experiments

We present an in situ uniaxial pressure device optimized for small angle x-ray and neutron scattering experiments at low-temperatures and high magnetic fields. A stepper motor generates force, which is transmitted to the sample via a rod with an integrated transducer that continuously monitors the force. The device has been designed to generate forces up to 200 N in both compressive and tensile configurations, and a feedback control allows operating the system in a continuous-pressure mode as the temperature is changed. The uniaxial pressure device can be used for various instruments and multiple cryostats through simple and exchangeable adapters. It is compatible with multiple sample holders, which can be easily changed depending on the sample properties and the desired experiment and allow rapid sample changes.

Microelectromechanical Transducer to Monitor High-Doses of Nuclear Irradiation

This paper reports the design, fabrication and measured performance of a passive microelectromechanical transducer for the wireless monitoring of high irradiation doses in nuclear environments. The sensing device is composed of a polymer material (high-density polyethylene) sealed inside a cavity. Subjected to ionizing radiation, this material releases various gases, which increases the pressure inside the cavity and deflects a dielectric membrane. From the measurement of the deflection, the variation of the applied pressure can be estimated, and, in turn, the dose may be determined. The microelectromechanical structure can also be used to study and validate the radiolysis properties of the polymer through its gas emission yield factor. Measurement of the dielectric membrane deflection is performed here to validate on the one hand the required airtightness of the cavity exposed to doses about 4 MGy and on the other hand, the functionality of the fabricated dosimeter for doses up to 80 kGy. The selection of appropriate materials for the microelectromechanical device is discussed, and the outgassing properties of the selected high-density polyethylene are analysed. Moreover, the technological fabrication process of the transducer is detailed.

A new high-pressure technique for the measurement of low frequency seismic attenuation using cyclic torsional loading

We report a new technique for torsional testing of materials under giga-pascal pressures, which uses a shearing module in a large-volume Paris-Edinburgh press in combination with high-resolution fast radiographic x-ray imaging. The measurement of the relative amplitude and phase lag between the cyclic displacement in the sample and a standard material (Al₂O₃) provides the effective shear modulus and attenuation factor for the sample. The system can operate in the 0.001-0.01 Hz frequency range and up to 5 GPa and 2000 K although high-temperature measurements may be affected by grain growth and plastic strain. Preliminary experimental results on San Carlos olivine are in quantitative agreement with previously reported Q^-1 factors at lower pressure. This cyclic torsional loading method opens new directions to quantify the viscoelastic properties of minerals/rocks at seismic frequencies and under pressure-temperature conditions relevant to the Earth's mantle for a better interpretation of seismological data.

Acoustofluidic rotational tweezing enables high-speed contactless morphological phenotyping of zebrafish larvae

Modern biomedical research and preclinical pharmaceutical development rely heavily on the phenotyping of small vertebrate models for various diseases prior to human testing. In this article, we demonstrate an acoustofluidic rotational tweezing platform that enables contactless, high-speed, 3D multispectral imaging and digital reconstruction of zebrafish larvae for quantitative phenotypic analysis. The acoustic-induced polarized vortex streaming achieves contactless and rapid (~1 s/rotation) rotation of zebrafish larvae. This enables multispectral imaging of the zebrafish body and internal organs from different viewing perspectives. Moreover, we develop a 3D reconstruction pipeline that yields accurate 3D models based on the multi-view images for quantitative evaluation of basic morphological characteristics and advanced combinations of metrics. With its contactless nature and advantages in speed and automation, our acoustofluidic rotational tweezing system has the potential to be a valuable asset in numerous fields, especially for developmental biology, small molecule screening in biochemistry, and pre-clinical drug development in pharmacology.

Gestion d’une épidémie active de COVID-19 sur un camp de Roms étendu et séroprévalence élevée en post-épidémie

Introduction

Les consultations dédiées aux personnes en situation de précarité ont été arrêtés au début de la vague épidémique. Plusieurs résidents d’un grand camp de Roms originaires de Moldavie (composé de plus de 600 habitants) ont été hospitalisés pour des formes sévères de COVID-19. L’objectif de ce travail est de dresser le bilan de l’intervention mise en place et de décrire la séroprévalence du Covid-19 sur le camp en post-épidémie.

Matériels et méthodes

Fin mars, une « équipe mobile précarité Covid » hospitalière multidisciplinaire a été créée pour intervenir quotidiennement directement sur les camps et détecter et prendre en charge les cas probables de COVID-19. En post-épidémie, une action de dépistage sérologique du COVID-19, de la varicelle (chez les 11–40 ans sans antécédents) et du VIH-VHB-VHC a été réalisée. Une analyse descriptive des données cliniques et biologiques recueillies est présentée.

Résultats

L’équipe mobile est intervenue quotidiennement sur le camp du 31/03 au 27/05 (43 interventions) et a effectué un total de 841 consultations dont 128 (15,2 %) pour Covid probable et 106 (12,6 %) pour Covid possible (toux sans fièvre, rhinite). Vingt-deux patients (2,6 %) ont été évacués sur les urgences et 7 ont été secondairement hospitalisés. Seuls 4 cas de Covid probables ou prouvés ont accepté un hébergement en centre Covid, tous les autres ayant refusé. Sur la période, 42 cas ont été confirmés par PCR lorsqu’ils étaient hospitalisés ou quand les PCR ont pu être réalisées par l’équipe mobile à partir de mi-avril. La majorité des consultations sollicitées par les habitants du camp concernait des pathologies variées autres (diabète, HTA, grossesse, ectoparasitose, viroses infantiles, etc.). Suite à l’hospitalisation d’un cas de varicelle, à l’incertitude sur le niveau d’immunité varicelle et Covid et à la disponibilité des tests sérologiques sur l’hôpital, il a été décidé de réaliser une action de dépistage et de vaccination large sur une durée de 10 jours (25/5–5/6). Parmi les 211 personnes prélevées (65 % de femmes, âge médian 42 ans [26–51], 26 ≤ 18 ans), la séroprévalence du contact avec le SARS-CoV2 est de 75,6 % (152/211), du VIH de 3,5 % (6/170 dont 2 femmes enceinte), du VHC de 10,6 % (17/160), de l’AgHBs de 1,8 % (3/164) et de la varicelle de 92,21 % (71/77).

Conclusion

Ce large camps de Roms a fait face à une épidémie massive de SARS-CoV-2 qui n’a pas pu être prévenue mais a pu être gérée directement sur le camp par une équipe d’aller vers. Le diagnostic récent de 4 cas PCR+ questionne le seuil d’immunité de groupe. L’intégration à l’action du dépistage de viroses chroniques méconnues et des consultations de soins primaires a permis de répondre à la demande d’une population rencontrant des difficultés majeures d’accès aux soins exacerbé par le confinement.

Loss-of-function mutations in MRAP2 are pathogenic in hyperphagic obesity with hyperglycemia and hypertension

The G-protein-coupled receptor (GPCR) accessory protein MRAP2 is implicated in energy control in rodents, notably via melanocortin-4 receptor (MC4R)¹. Although some MRAP2 mutations have been described in people with obesity^1–3, their functional consequences on adiposity remain elusive. Using large-scale sequencing of MRAP2 in 9,418 people, we identified 23 rare heterozygous variants associated with increased obesity risk in both adults and children. Functional assessment of each variant shows that loss-of-function MRAP2 variants are pathogenic for monogenic hyperphagic obesity, with hyperglycemia and hypertension. This contrasts with other monogenic forms of obesity characterized by excessive hunger, including MC4R deficiency, that present with low blood pressure and normal glucose tolerance⁴. The pleiotropic metabolic effect of loss-of-function mutations in MRAP2 might be due to the failure of different MRAP2-regulated GPCRs in various tissues including pancreatic islets.

Contactless, programmable acoustofluidic manipulation of objects on water

Contact-free manipulation of small objects (e.g., cells, tissues, and droplets) using acoustic waves eliminates physical contact with structures and undesired surface adsorption. Pioneering acoustic-based, contact-free manipulation techniques (e.g., acoustic levitation) enable programmable manipulation but are limited by evaporation, bulky transducers, and inefficient acoustic coupling in air. Herein, we report an acoustofluidic mechanism for the contactless manipulation of small objects on water. A hollow-square-shaped interdigital transducer (IDT) is fabricated on lithium niobate (LiNbO3), immersed in water and used as a sound source to generate acoustic waves and as a micropump to pump fluid in the ±x and ±y orthogonal directions. As a result, objects which float adjacent to the excited IDT can be pushed unidirectionally (horizontally) in ±x and ±y following the directed acoustic wave propagation. A fluidic processor was developed by patterning IDT units in a 6-by-6 array. We demonstrate contactless, programmable manipulation on water of oil droplets and zebrafish larvae. This acoustofluidic-based manipulation opens avenues for the contactless, programmable processing of materials and small biosamples.

Polyketide Synthase Plays a Conserved Role in Otolith Formation

Otoliths (ear stones) are biomineralized complexes essential for the balancing and hearing function of the inner ears in fish. Their formation is controlled by a genetically programmed biological process that is yet to be defined. We have isolated and characterized a spontaneous genetic mutant zebrafish with a complete absence of otoliths, named no otolith 1 (not1). not1 mutants are unable to develop otoliths during embryonic stages and fail to respond to acoustic stimuli, indicating an inner ear defect. We identified a deleterious mutation (G239R) that altered a highly conserved amino acid residue in the zebrafish ortholog of type I polyketide synthase (pks1) to underlie these phenotypes and showed that expression of the polyketide synthase gene of Japanese medaka fish could rescue the otolith deficiency in not1 mutant zebrafish. Our finding highlights a critical and conserved role of type I polyketide synthase in the initiation of otolith formation. Given the functional homology between otoliths in teleost fish and otoconia in mammals and humans, not1 mutants provide a new animal model for the study of human otoconia-related diseases.

A novel NEUROG3 mutation in neonatal diabetes associated with a neuro-intestinal syndrome

Neonatal diabetes mellitus (NDM) is a rare form of non-autoimmune diabetes usually diagnosed in the first 6 months of life. Various genetic defects have been shown to cause NDM with diverse clinical presentations and variable severity. Among transcriptional factor genes associated with isolated or syndromic NDM, a few cases of homozygous mutations in the NEUROG3 gene have been reported, all mutated patients presenting with congenital malabsorptive diarrhea with or without diabetes at a variable age of onset from early life to childhood. Through a targeted next-generation sequencing assay for monogenic diabetes genes, we aimed to search for pathogenic deleterious mutation in a Turkish patient with NDM, severe malabsorptive diarrhea, neurointestinal dysplasia and other atypical features. In this patient, we identified a novel homozygous nonsense mutation (p.Q4*) in NEUROG3. The same biallelic mutation was found in another affected family member. Of note, the study proband presents with abnormalities of the intrahepatic biliary tract, thyroid gland and central nervous system, which has never been reported before in NEUROG3 mutation carriers. Our findings extend the usually described clinical features associated with NEUROG3 deficiency in humans, and question the extent to which a complete lack of NEUROG3 expression may affect pancreas endocrine function in humans.

[Orthodontics and Alexis Schange in 1841]

INTRODUCTION

Alexis Schange was one of the first practitioners able to use accurate casts of the dental arches thanks to the invention of the impression-tray by Delabarre. Consequently, his diagnoses were more precise and his appliances fitted better than those of his predecessors.

MATERIALS AND METHOD

The author will first outline the status of Orthodontics prior to Schange and the advent of the first casts, before describing Schange's contribution to Orthodontics.

DISCUSSION

In 1841, Schange published his "Handbook of Dental Uprighting", a clear and pedagogical work and undoubtedly the best over the many years when Orthodontics was exclusively European.

[Optimization of the final lingual occlusion: an analysis]

INTRODUCTION

The objectives of orthodontic treatment are to achieve a functional, aesthetic and sustainable occlusion. However, its analysis is often limited to the study of its buccal side, easy to check in mouth. Yet, the lingual occlusion is also of paramount importance.

MATERIAL AND METHOD

After calling to mind the ideal static objectives of treatment, described by some authors and defined by some scientific societies, this article studies the different supports for the analysis of lingual static occlusion and proposes a new protocol for the carving of orthodontic casts.

RESULTS

The lingual occlusion end-of-treatment objectives lack details, whether by the scientific societies or literature, although we possess simple ways to study them.

DISCUSSION

The lingual part of occlusion is rarely studied in our daily practice, particularly because its analysis cannot be achieved by a direct intraoral examination. However, it is of major importance in the success and stability of our treatments.

A truncating mutation in CEP55 is the likely cause of MARCH, a novel syndrome affecting neuronal mitosis

Background

Hydranencephaly is a congenital anomaly leading to replacement of the cerebral hemispheres with a fluid-filled cyst. The goals of this work are to describe a novel autosomal-recessive syndrome that includes hydranencephaly (multinucleated neurons, anhydramnios, renal dysplasia, cerebellar hypoplasia and hydranencephaly (MARCH)); to identify its genetic cause(s) and to provide functional insight into pathomechanism.

Methods

We used homozygosity mapping and exome sequencing to identify recessive mutations in a single family with three affected fetuses. Immunohistochemistry, RT-PCR and imaging in cell lines, and zebrafish models, were used to explore the function of the gene and the effect of the mutation.

Results

We identified a homozygous nonsense mutation in CEP55 segregating with MARCH. Testing the effect of this allele on patient-derived cells indicated both a reduction of the overall CEP55 message and the production of a message that likely gives rise to a truncated protein. Suppression or ablation of cep55l in zebrafish embryos recapitulated key features of MARCH, most notably renal dysplasia, cerebellar hypoplasia and craniofacial abnormalities. These phenotypes could be rescued by full-length but not truncated human CEP55 message. Finally, we expressed the truncated form of CEP55 in human cells, where we observed a failure of truncated protein to localise to the midbody, leading to abscission failure and multinucleated daughter cells.

Conclusions

CEP55 loss of function mutations likely underlie MARCH, a novel multiple congenital anomaly syndrome. This association expands the involvement of centrosomal proteins in human genetic disorders by highlighting a role in midbody function.

Development of synchrotron X-ray micro-tomography under extreme conditions of pressure and temperature

X-ray tomography is a non-destructive three-dimensional imaging/microanalysis technique selective to a wide range of properties such as density, chemical composition, chemical states and crystallographic structure with extremely high sensitivity and spatial resolution. Here the development of in situ high-pressure high-temperature micro-tomography using a rotating module for the Paris-Edinburgh cell combined with synchrotron radiation is described. By rotating the sample chamber by 360°, the limited angular aperture of ordinary high-pressure cells is surmounted. Such a non-destructive high-resolution probe provides three-dimensional insight on the morphological and structural evolution of crystalline as well as amorphous phases during high pressure and temperature treatment. To demonstrate the potentials of this new experimental technique the compression behavior of a basalt glass is investigated by X-ray absorption tomography, and diffraction/scattering tomography imaging of the structural changes during the polymerization of C₆₀ molecules under pressure is performed. Small size and weight of the loading frame and rotating module means that this apparatus is portable, and can be readily installed on most synchrotron facilities to take advantage of the diversity of three-dimensional imaging techniques available at beamlines. This experimental breakthrough should open new ways for in situ imaging of materials under extreme pressure-temperature-stress conditions, impacting diverse areas in physics, chemistry, geology or materials sciences.

[The birth of Edgewise or the last and best Angle's mechanisms]

INTRODUCTION

Mechanical forces applied to the teeth constitute a not-insignificant feature of orthodontic treatment. Edgewise, the most commonly used type of mechanics, was introduced 88 years ago and has become a standard worldwide. The invention of Edgewise by E.H. Angle in 1928 is an event in the history of orthodontics which deserves to be recalled.

MATERIALS AND METHODS

Starting with the initial search for this method and leading up to a presentation of the technique itself, this paper provides an overview of the history of Angle mechanics.

RESULTS

In order to demonstrate the first mechanical system to function in the three planes of space, Angle provided precise diagrams and instructions for use while insisting, on several occasions, that his mechanics was not complicated and that careful study should allow users to overcome any potential difficulties.

DISCUSSION

The mechanism as devised by Angle, who died shortly after launching his invention, was only used for a short length of time. However, all subsequently invented therapeutic techniques incorporated the mechanical principles underpinning Edgewise, paying tribute in this way to a great invention.

What Is the Best NGS Enrichment Method for the Molecular Diagnosis of Monogenic Diabetes and Obesity?

Molecular diagnosis of monogenic diabetes and obesity is of paramount importance for both the patient and society, as it can result in personalized medicine associated with a better life and it eventually saves health care spending. Genetic clinical laboratories are currently switching from Sanger sequencing to next-generation sequencing (NGS) approaches but choosing the optimal protocols is not easy. Here, we compared the sequencing coverage of 43 genes involved in monogenic forms of diabetes and obesity, and variant detection rates, resulting from four enrichment methods based on the sonication of DNA (Agilent SureSelect, RainDance technologies), or using enzymes for DNA fragmentation (Illumina Nextera, Agilent HaloPlex). We analyzed coding exons and untranslated regions of the 43 genes involved in monogenic diabetes and obesity. We found that none of the methods achieves yet full sequencing of the gene targets. Nonetheless, the RainDance, SureSelect and HaloPlex enrichment methods led to the best sequencing coverage of the targets; while the Nextera method resulted in the poorest sequencing coverage. Although the sequencing coverage was high, we unexpectedly found that the HaloPlex method missed 20% of variants detected by the three other methods and Nextera missed 10%. The question of which NGS technique for genetic diagnosis yields the highest diagnosis rate is frequently discussed in the literature and the response is still unclear. Here, we showed that the RainDance enrichment method as well as SureSelect, which are both based on the sonication of DNA, resulted in a good sequencing quality and variant detection, while the use of enzymes to fragment DNA (HaloPlex or Nextera) might not be the best strategy to get an accurate sequencing.

Genetic variants in LEP, LEPR, and MC4R explain 30% of severe obesity in children from a consanguineous population

OBJECTIVE

Single gene mutations leading to severe obesity have so far been identified in 3-5% cases in European populations. However, prevalence of these pathogenic mutations has not systematically been examined in specific consanguineous populations. Here we describe the incidence of obesity-associated mutations through a step-wise sequence analysis, in a cohort of 73 Pakistani children with severe obesity from consanguineous families.

METHODS

Initially, all subjects were screened for mutations in coding regions of leptin (LEP) and melanocortin 4 receptor (MC4R) genes by direct sequencing. Subjects negative for mutation in these genes were screened using microdroplet PCR enrichment and NGS. Genomic structural variation was assessed by genotyping. Serum leptin, insulin, and cortisol were determined by ELISA.

RESULTS

Among 73 children with severe obesity (BMI SDS > 3.0), we identified 22 probands and 5 relatives, carrying 10 different loss-of-function homozygous mutations in LEP, leptin receptor (LEPR), and MC4R genes, including 4 novel variants. Hypercortisolemia was significantly emphasized in LEP mutation carriers.

CONCLUSIONS

The prevalence of pathogenic mutations in genes known to directly influence leptin-melanocortin signaling is 30% in our cohort. The results of this study emphasize the desirability of undertaking systematic and in-depth genetic analysis of cases with severe obesity in specific consanguineous populations.

[The prehistory of orthodontics]

Orthodontics came into being in 1728. Previously, practitioners were at a loss when confronted with crooked teeth. A Latin philosopher had an ingenious flash of orthodontic inspiration. Other authors were content to either extract the malposed teeth or to modify their shape. However, interest in an approach to preventive orthodontics had now begun.

[Inborn errors of metabolism: transition from childhood to adulthood]

Inborn errors of metabolism (IEM) are due to mutations of genes coding for enzymes of intermediary metabolism and are classified into 3 broad categories: 1) intoxication, 2) energy defect and 3) cellular organelles synthesis or catabolism defect. Improvements of therapy over these last 20 years has improved prognosis of children with IEM. These children grow up and should have their transition to specialized adult care. Adult patients with IEM are a relatively new phenomenon with currently only limited knowledge. Extrapolated pediatric guidelines are applied to the adult population taking into account adult life stages (social independence, pregnancy, aging process and potential long-term complications).

Picosecond acoustics method for measuring the thermodynamical properties of solids and liquids at high pressure and high temperature

Based on the original combination of picosecond acoustics and diamond anvils cell, recent improvements to accurately measure hypersonic sound velocities of liquids and solids under extreme conditions are described. To illustrate the capability of this technique, results are given on the pressure and temperature dependence of acoustic properties for three prototypical cases: polycrystal (iron), single-crystal (silicon) and liquid (mercury) samples. It is shown that such technique also enables the determination of the density as a function of pressure for liquids, of the complete set of elastic constants for single crystals, and of the melting curve for any kind of material. High pressure ultrafast acoustic spectroscopy technique clearly opens opportunities to measure thermodynamical properties under previously unattainable extreme conditions. Beyond physics, this state-of-the-art experiment would thus be useful in many other fields such as nonlinear acoustics, oceanography, petrology, in of view. A brief description of new developments and future directions of works conclude the article.

[News in endocrinology: Management of asymptomatic primary hyperparathyroidism in 2014]

Primary hyperparathyroidism, a disorder in wich there is a hypercalcemia caused by autonomous hypersecretion of parathormone, usually by parathyroid adenoma. It is asymptomatic in most cases. After excluding a cause of secondary elevation of parathyroid hormone, a search for renal stones and osteoporosis has to be done. The treatment of choice is parathyroidectomy and it is recommended in case of complications, hypercalcemia with calcium up to 0.25 mmol/l higher than the upper limit and in patients <50 years. Specific pharmacological approaches (bisphosphonate or cinacalcet) may be of value if the patient meet surgical guidelines but is not a candidate for parathyroid surgery. Patient who do not meet surgical indications should be monitored.

A nonsense loss-of-function mutation in PCSK1 contributes to dominantly inherited human obesity

BACKGROUND

A significant proportion of severe familial forms of obesity remain genetically elusive. Taking advantage of our unique cohort of multigenerational obese families, we aimed to assess the contribution of rare mutations in 29 common obesity-associated genes to familial obesity, and to evaluate in these families the putative presence of nine known monogenic forms of obesity.

METHODS

Through next-generation sequencing, we sequenced the coding regions of 34 genes involved in polygenic and/or monogenic forms of obesity in 201 participants (75 normal weight individuals, 54 overweight individuals and 72 individuals with obesity class I, II or III) from 13 French families. In vitro functional analyses were performed to investigate the mutation PCSK1-p.Arg80* which was identified in a family.

RESULTS

A novel heterozygous nonsense variant in PCSK1 (p.Arg80*), encoding a propeptide truncated to less than two exons (out of 14), was found to co-segregate with obesity in a three-generation family. We demonstrated that this mutation inhibits PCSK1 enzyme activity and that this inhibition most likely does not involve a strong physical interaction. Furthermore, both mutations PCSK1-p.Asn180Ser and POMC-p.Phe144Leu, which had previously been reported to be associated with severe obesity, were also identified in this study, but did not co-segregate with obesity. Finally, we did not identify any rare mutations co-segregating with obesity in common obesity susceptibility genes, except for CADM2 and QPCTL, where we found two novel variants (p.Arg81His and p.Leu98Pro, respectively) in three obese individuals.

CONCLUSIONS

We showed for the first time that a nonsense mutation in PCSK1 was likely to cause dominantly inherited human obesity, due to the inhibiting properties of the propeptide fragment encoded by the null allele. Furthermore, the present family sequencing design challenged the contribution of previously reported mutations to monogenic or at least severe obesity.

[Testosterone: a treatment for the prevention of cardiovascular disease]

Testosterone treatment was largely prescribed and marketed as a potential therapy to treat symptoms of aging. Testosterone levels decrease progressively with aging and low testosterone levels were associated with an increase risk of cardiovascular events and death. Controversies persist whether this association is causal or mediated by confounders of the general health. Systematic screening of testosterone is not recommended in a check-up visit, but only in case of suggestive symptoms. Furthermore a recent meta-analysis and large prospective cohort studies have reported a concern regarding the safety of testosterone therapy and the associated risk of major cardiovascular events. The decision to prescribe testosterone should be made with the patient after evaluating the risks and benefits.

Novel LEPR mutations in obese Pakistani children identified by PCR-based enrichment and next generation sequencing

OBJECTIVE

Mutations in leptin receptor gene (LEPR) result in early onset extreme adiposity. However, their prevalence in different populations is not known. Indeed, LEPR screening by gold standard Sanger sequencing has been limited by its large size and the cost. One-step PCR-based targeted enrichment could be an option for rapid and cost effective molecular diagnosis of monogenic forms of obesity.

METHODS

The study is based on 39 unrelated severely obese Pakistani children, previously shown to be negative for leptin (LEP) and melanocortin 4 receptor (MC4R) gene mutations, from an initial cohort of 62 probands. Patient samples were analyzed by microdroplet PCR-enrichment (RainDance technologies) targeting coding exons of 26 obesity-associated genes combined with next generation sequencing. Hormone levels were analyzed by ELISA.

RESULTS

The analysis revealed two novel homozygous LEPR mutations, an essential splice site mutation in exon 15 (c.2396-1 G>T), and a nonsense mutation in exon 10 (c.1675 G>A). Both probands had high leptin levels and were phenotypically indistinguishable from age-matched leptin-deficient subjects from the same population.

CONCLUSIONS

The two subjects carrying homozygous LEPR mutations, reported here for the first time in the Pakistani population, constitute 3% of the whole cohort of severely obese children (compared to 17% for LEP and 3% for MC4R).

[What makes a pleasing face]

Regular faces are beautiful because they are expressive and arouse an interest in the observer due to the variations in their shape, their surface appearance and their movements. The sensitivity of the eye of the beholder is correlated to the expressivity of the face and of the dentition. Better, however, to avoid any indication of aggression that could foreshadow the senescence of the face.

Highly sensitive diagnosis of 43 monogenic forms of diabetes or obesity through one-step PCR-based enrichment in combination with next-generation sequencing

OBJECTIVE

Accurate etiological diagnosis of monogenic forms of diabetes and obesity is useful as it can lead to marked improvements in patient care and genetic counseling. Currently, molecular diagnosis based on Sanger sequencing is restricted to only a few genes, as this technology is expensive, time-consuming, and labor-intensive. High-throughput next-generation sequencing (NGS) provides an opportunity to develop innovative cost-efficient methods for sensitive diabetes and obesity multigene screening.

RESEARCH DESIGN AND METHODS

We assessed a new method based on PCR enrichment in microdroplets (RainDance Technologies) and NGS using the Illumina HiSeq2000 for the molecular diagnosis of 43 forms of monogenic diabetes or obesity. Forty patients carrying a known causal mutation for those subtypes according to diagnostic laboratories were blindly reanalyzed.

RESULTS

Except for one variant, we reidentified all causal mutations in each patient associated with an almost-perfect sequencing of the targets (mean of 98.6%). We failed to call one highly complex indel, although we identified a dramatic drop of coverage at this locus. In three patients, we detected other mutations with a putatively deleterious effect in addition to those reported by the genetic diagnostic laboratories.

CONCLUSIONS

Our NGS approach provides an efficient means of highly sensitive screening for mutations in genes associated with monogenic forms of diabetes and obesity. As cost and time to deliver results have been key barriers to uncovering a molecular cause in the many undiagnosed cases likely to exist, the present methodology should be considered in patients displaying features of monogenic diabetes or obesity.

[New developments in cephalometrics]

Recently l recalled the error in the principle which makes cephalometric analysis unsuitable for orthodontic diagnosis. Now, three methods of analysis have been published precisely conceived in order to avoid this error. Will cephalometric analysis succeed in its search for the truth?

[Non diabetic hypoglycemia: diagnosis and management]

Organic or non diabetic hypoglycemia (NDH) is a rare disease when it is confirmed, but is often confounded with low blood glucose concentration (between 3 and 4 mmol/I), which is much more frequent. NDH's definition requires the Whipple triad (plasma glucose level <2.8 mmol/l, symptoms of neuroglycopenia and their relief with administration of sugar). The diagnostic approach needs to differentiate the healthy from the sick patient, who's hypoglycemia causes are multiple and frequent, such as: toxic (medicament, OH), organ deficiency, denutrition and sepsis. When hypoglycemia is suspected, without evident causes in healthy persons, it should be investigated by a 72 h fast test, in order to guide the diagnosis. After confirmation of an endogen hyperinsulinism only, sophisticated imaging should be done to localize the tumor and/or to exclude alternatives diagnosis.

[Sport and type 1 diabetes]

Physical activity is recognised to be an efficient measure in improving glycemic control in the treatment of type 2 diabetes. This evidence is lacking in type I diabetes but type 1I diabetics benefit from the same advantages like the general population. For many type I diabetics, especially younger patients, sport represents an important modality in the treatment of their disease but also of their quality of life. However, this is often a challenge for the patient as well as for the physician regarding the metabolic consequences (hypo- but also hyperglycemia) which can appear in relation with physical activity. There are existing general recommendations concerning the intake of carbohydrates and the reduction of insulin doses but those have to be adapted individually for each patient and depend significantly on different sports and on the intensity of sport.

[Diabetes in elderly: a tailored management]

In developed countries, 12-25 % of the aged population (>65 years old) have diabetes. Treatment of the old diabetic patients is less well studied compared to younger patients although diabetic and geriatric medical associations have issued specific treatment and priority guidelines for these patients. Treatment and targets of glycemic control must be adapted to the functional condition of the patients, prevent symptoms and complications of the geriatric syndrome. Prevention and screening of chronic complication of diabetes have to be integrated in the overall care of aged diabetic patients to optimize their quality of life and health state.

Reassessment of the putative role of BLK-p.A71T loss-of-function mutation in MODY and type 2 diabetes

AIMS/HYPOTHESIS

MODY is believed to be caused by at least 13 different genes. Five rare mutations at the BLK locus, including only one non-synonymous p.A71T variant, were reported to segregate with diabetes in three MODY families. The p.A71T mutation was shown to abolish the enhancing effect of BLK on insulin content and secretion from pancreatic beta cell lines. Here, we reassessed the contribution of BLK to MODY and tested the effect of BLK-p.A71T on type 2 diabetes risk and variations in related traits.

METHODS

BLK was sequenced in 64 unelucidated MODY samples. The BLK-p.A71T variant was genotyped in a French type 2 diabetes case-control study including 4,901 cases and 4,280 controls, and in the DESIR (Data from an Epidemiological Study on the Insulin Resistance Syndrome) and SUVIMAX (Supplementation en Vitamines et Mineraux Antioxydants) population-based cohorts (n = 6,905). The variant effects were assessed by logistic and linear regression models.

RESULTS

No rare non-synonymous BLK mutations were found in the MODY patients. The BLK p.A71T mutation was present in 52 normoglycaemic individuals, making it very unlikely that this loss-of-function mutation causes highly penetrant MODY. We found a nominal association between this variant and increased type 2 diabetes risk, with an enrichment of the mutation in the obese diabetic patients, although no significant association with BMI was identified.

CONCLUSIONS/INTERPRETATION

No mutation in BLK was found in our MODY cohort. From our findings, the BLK-p.A71T mutation may weakly influence type 2 diabetes risk in the context of obesity; however, this will require further validation.

Autonomous and self-sustained circadian oscillators displayed in human islet cells

AIMS/HYPOTHESIS

Following on from the emerging importance of the pancreas circadian clock on islet function and the development of type 2 diabetes in rodent models, we aimed to examine circadian gene expression in human islets. The oscillator properties were assessed in intact islets as well as in beta cells.

METHODS

We established a system for long-term bioluminescence recording in cultured human islets, employing lentivector gene delivery of the core clock gene Bmal1 (also known as Arntl)-luciferase reporter. Beta cells were stably labelled using a rat insulin2 promoter fluorescent construct. Single-islet/cell oscillation profiles were measured by combined bioluminescence-fluorescence time-lapse microscopy.

RESULTS

Human islets synchronised in vitro exhibited self-sustained circadian oscillations of Bmal1-luciferase expression at both the population and single-islet levels, with period lengths of 23.6 and 23.9 h, respectively. Endogenous BMAL1 and CRY1 transcript expression was circadian in synchronised islets over 48 h, and antiphasic to REV-ERBα (also known as NR1D1), PER1, PER2, PER3 and DBP transcript circadian profiles. HNF1A and PDX1 exhibited weak circadian oscillations, in phase with the REV-ERBα transcript. Dispersed islet cells were strongly oscillating as well, at population and single-cell levels. Importantly, beta and non-beta cells revealed oscillatory profiles that were well synchronised with each other.

CONCLUSIONS/INTERPRETATION

We provide for the first time compelling evidence for high-amplitude cell-autonomous circadian oscillators displayed in human pancreatic islets and in dispersed human islet cells. Moreover, these clocks are synchronised between beta and non-beta cells in primary human islet cell cultures.

Biofeedback can reduce foot pressure to a safe level and without causing new at-risk zones in patients with diabetes and peripheral neuropathy

BACKGROUND

Plantar pressure reduction is mandatory for diabetic foot ulcer healing. Our aim was to evaluate the impact of a new walking strategy learned by biofeedback on plantar pressure distribution under both feet in patients with diabetic peripheral neuropathy.

METHODS

Terminally augmented biofeedback has been used for foot off-loading training in 21 patients with diabetic peripheral sensory neuropathy. The biofeedback technique was based on a subjective estimation of performance and objective visual feedback following walking sequences. The patient was considered to have learned a new walking strategy as soon as the peak plantar pressure (PPP) under the previously defined at-risk zone was within a range of 40-80% of baseline PPP in 70% of the totality of steps and during three consecutive walking sequences. The PPP was measured by a portable in-shoe foot pressure measurement system (PEDAR(®)) at baseline (T0), directly after learning (T1) and at 10-day retention test (T2).

RESULTS

The PPP under at-risk zones decreased significantly at T1 (165 ± 9 kPa, p < 0.0001) and T2 (167 ± 11, p = 0.001), as compared with T0 (242 ± 12 kPa) without any increase of the PPP elsewhere. At the contralateral foot (not concerned by off-loading), the PPP was slightly higher under the lateral midfoot at T1 (68 ± 8 kPa, p = 0.01) and T2 (65 ± 8 kPa, p = 0.01), as compared with T0 (58 ± 6 kPa).

CONCLUSIONS

The foot off-loading by biofeedback leads to a safe and regular plantar pressure distribution without inducing any new 'at-risk' area under both feet.

Non-alcoholic fatty liver disease and insulin resistance: from bench to bedside

Non-alcoholic fatty liver disease (NAFLD) is now the most frequent chronic liver disease in the developed countries. There is also growing evidence from basic and clinical research that NAFLD has a strong relationship to insulin resistance, which is a key factor in the development of type 2 diabetes. The aim of this review is to summarize the recent important findings linking NAFLD and insulin resistance. Lipid accumulation, particularly of diacylglycerol, appears to be of major importance in this process. Mitochondrial dysfunction, through decreased mitochondrial biogenesis, increases oxidative stress, and ageing also plays an important role. Finally, endoplasmic reticulum stress and inflammation also probably contribute to the development of insulin resistance via mechanisms that are still not well understood. Clinical aspects of NAFLD, such as its diagnosis and management, are also investigated in this review.

Familial early-onset diabetes is not a typical MODY in several Tunisian patients

BACKGROUND

MODY (Maturity-onset diabetes of the young), a dominantly inherited form of early-onset diabetes, is clinically and genetically heterogeneous with more than ten genetic subtypes described worldwide.

AIM

To evaluate the possible existence of MODY in 12 young diabetic Tunisian patients by searching for mutations in the most prevalent MODY genes.

METHODS

Twelve patients with diabetes in 2-to-3 generations, all diagnosed before age 31, were screened for mutations and deletions in HNF1A, HNF4A, INS, IPF1, NEUROD1 and GCK genes by Sanger sequencing and by Multiplex ligation-dependent probe amplification assay.

RESULTS

The patients had no evidence of autoimmunity and a mean age at diabetes diagnosis of 25.66 ± 3.96 years with severe overt diabetes (fasting glycaemia: 10.91 ± 3.55 mmol/ l; HbA1c: 10.46 ± 3.31 %). Two subjects were initially treated with insulin. On the ten initially treated with OHA or on diet, eight converted to insulin therapy (within 3 months to 20 years). Molecular analysis showed only one missense HNF4A mutation (I453V) in one family. No mutations in the studied genes were detected in the other patients.

CONCLUSION

A molecular defect in known MODY genes has been excluded in 11 patients with early-onset diabetes suggesting that other genetic causes may explain diabetes in these families. In such cases, new generation sequencing approaches may be well appropriate to identify specific molecular etiologies from extended families and to establish a strategy of molecular diagnostic of MODY in Tunisia.

[Search of a cephalometric reference line]

The variability of cephalometric reference lines is examined in this article with regard to typology, natural orientation of the head, orientation by the vestibular system, and anatomy. It appears that these lines have orientations that vary with individual subjects, that is, a line is not the same in a specific person as it is in a theoretical model that is based on average values. It follows from this that the deviation observed between a patient's measurement and the average could just as well reflect variations in the reference lines as it does of those of the structures being studied. Such a measurement cannot, accordingly, serve as the basis for a morphological diagnosis. To deal with this problem, we propose another cephalometric reference system that presents, for orthognathic diagnosis, many advantages over the traditional system but, itself, remains imperfect.

Whole-exome sequencing and high throughput genotyping identified KCNJ11 as the thirteenth MODY gene

Background

Maturity-onset of the young (MODY) is a clinically heterogeneous form of diabetes characterized by an autosomal-dominant mode of inheritance, an onset before the age of 25 years, and a primary defect in the pancreatic beta-cell function. Approximately 30% of MODY families remain genetically unexplained (MODY-X). Here, we aimed to use whole-exome sequencing (WES) in a four-generation MODY-X family to identify a new susceptibility gene for MODY.

Methodology

WES (Agilent-SureSelect capture/Illumina-GAIIx sequencing) was performed in three affected and one non-affected relatives in the MODY-X family. We then performed a high-throughput multiplex genotyping (Illumina-GoldenGate assay) of the putative causal mutations in the whole family and in 406 controls. A linkage analysis was also carried out.

Principal Findings

By focusing on variants of interest (i.e. gains of stop codon, frameshift, non-synonymous and splice-site variants not reported in dbSNP130) present in the three affected relatives and not present in the control, we found 69 mutations. However, as WES was not uniform between samples, a total of 324 mutations had to be assessed in the whole family and in controls. Only one mutation (p.Glu227Lys in KCNJ11) co-segregated with diabetes in the family (with a LOD-score of 3.68). No KCNJ11 mutation was found in 25 other MODY-X unrelated subjects.

Conclusions/Significance

Beyond neonatal diabetes mellitus (NDM), KCNJ11 is also a MODY gene (‘MODY13’), confirming the wide spectrum of diabetes related phenotypes due to mutations in NDM genes (i.e. KCNJ11, ABCC8 and INS). Therefore, the molecular diagnosis of MODY should include KCNJ11 as affected carriers can be ideally treated with oral sulfonylureas.

[Diabetic nephropathy: an update]

Diabetes has a constantly growing prevalence and leads to a number of complications such as diabetic nephropathy. A systematic screening and an adapted management are needed to limit the renal and also the cardiovascular complications linked to diabetic nephropathy. An adequate glycemic and tensional control and control of proteinuria are the priority in the care of diabetic nephropathy. Other aspects such as phospho-calcium balance, lipid panel or lifestyle changes are also important and therefore a multidisciplinary approach is essential. A better understanding of the physiopathology may lead to even more effective treatments in the future. We resume in this article the actual management of a patient suffering from diabetic nephropathy and the future treatment perspectives.

Clinical and metabolic features of adult-onset diabetes caused by ABCC8 mutations

OBJECTIVE

Gain-of-function ABCC8/sulfonylurea (SU) receptor 1 mutations cause neonatal diabetes mellitus (NDM) or late-onset diabetes in adult relatives. Given the effectiveness of SU treatment in ABCC8-NDM patients, we further characterized late-onset ABCC8-associated diabetes.

RESEARCH DESIGN AND METHODS

Seven adult subjects from three NDM families and one family with type 2 diabetes were studied. Insulin secretion and insulin sensitivity were assessed using clamp techniques. We screened 139 type 2 diabetic patients who were well controlled by SU for ABCC8 mutations.

RESULTS

ABCC8 mutation carriers exhibited glucose intolerance, frank diabetes, or insulin-requiring diabetes since diagnosis. HbA(1c) improved in five SU-treated patients. Insulin secretion capacity was impaired in three patients compared with adult control subjects but was restored after a 4-week SU trial in two patients. Cohort screening revealed four SU-treated patients with ABCC8 mutations, two of which are likely causal.

CONCLUSIONS

Although of rare occurrence, recognition of adult-onset ABCC8-associated diabetes may help in targeting patients for SU therapy.

Human mutation within Per-Arnt-Sim (PAS) domain-containing protein kinase (PASK) causes basal insulin hypersecretion

PAS kinase (PASK) is a glucose-regulated protein kinase involved in the control of pancreatic islet hormone release and insulin sensitivity. We aimed here to identify mutations in the PASK gene that may be associated with young-onset diabetes in humans. We screened 18 diabetic probands with unelucidated maturity-onset diabetes of the young (MODY). We identified two rare nonsynonymous mutations in the PASK gene (p.L1051V and p.G1117E), each of which was found in a single MODY family. Wild type or mutant PASKs were expressed in HEK 293 cells. Kinase activity of the affinity-purified proteins was assayed as autophosphorylation at amino acid Thr307 or against an Ugp1p-derived peptide. Whereas the PASK p.G1117E mutant displayed a ∼25% increase with respect to wild type PASK in the extent of autophosphorylation, and a ∼2-fold increase in kinase activity toward exogenous substrates, the activity of the p.L1051V mutant was unchanged. Amino acid Gly1117 is located in an α helical region opposing the active site of PASK and may elicit either: (a) a conformational change that increases catalytic efficiency or (b) a diminished inhibitory interaction with the PAS domain. Mouse islets were therefore infected with adenoviruses expressing wild type or mutant PASK and the regulation of insulin secretion was examined. PASK p.G1117E-infected islets displayed a 4-fold decrease in glucose-stimulated (16.7 versus 3 mM) insulin secretion, chiefly reflecting a 4.5-fold increase in insulin release at low glucose. In summary, we have characterized a rare mutation (p.G1117E) in the PASK gene from a young-onset diabetes family, which modulates glucose-stimulated insulin secretion.