From Gel to Crystal: Mechanism of HfO2 and ZrO2 Nanocrystal Synthesis in Benzyl Alcohol

Nonaqueous sol-gel syntheses have been used to make many types of metal oxide nanocrystals. According to the current paradigm, nonaqueous syntheses have slow kinetics, thus favoring the thermodynamic (crystalline) product. Here we investigate the synthesis of hafnium (and zirconium) oxide nanocrystals from the metal chloride in benzyl alcohol. We follow the transition from precursor to nanocrystal through a combination of rheology, EXAFS, NMR, TEM, and X-ray total scattering (PDF analysis). Upon dissolving the metal chloride precursor, the exchange of chloride ligands for benzylalkoxide liberates HCl. The latter catalyzes the etherification of benzyl alcohol, eliminating water. During the temperature ramp to the reaction temperature (220 °C), sufficient water is produced to turn the reaction mixture into a macroscopic gel. Rheological analysis shows a network consisting of strong interactions with temperature-dependent restructuring. After a few minutes at the reaction temperature, crystalline particles emerge from the gel, and nucleation and growth are complete after 30 min. In contrast, 4 h are required to obtain the highest isolated yield, which we attribute to the slow in situ formation of water (the extraction solvent). We used our mechanistic insights to optimize the synthesis, achieving high isolated yields with a reduced reaction time. Our results oppose the idea that nonaqueous sol-gel syntheses necessarily form crystalline products in one step, without a transient, amorphous gel state.

Effect of Poly(Vinyl Pyrrolidone) on Iodine Release from Acrylate-Endcapped Urethane-Based Poly(Ethylene Glycol) Hydrogels as Antibacterial Wound Dressing

Infections are still a major cause of morbidity in burn wounds. Although silver has been used strongly in past centuries as an anti-bacterial, it can lead to allergic reactions, bacterial resistance, and delayed wound healing. Iodine-based antibacterials are becoming an interesting alternative. In this work, the effect of complexation with poly(vinyl pyrrolidone) (PVP) and poly(ethylene oxide) (PEO)-based polymers is explored by using different acrylate-endcapped urethane-based poly(ethylene glycol) (AUP) polymers, varying the molar mass (MM) of the poly(ethylene glycol) (PEG) backbone, with possible addition of PVP. The higher MM AUP outperforms the swelling potential of commercial wound dressings such as Kaltostat, Aquacel Ag, and Hydrosorb and all MM show superior mechanical properties. The addition of iodine to the polymers is compared to Iso-Betadine Tulle (IBT). Interestingly, the addition of PVP does not lead to increased iodine complexation compared to the blank AUP polymers, while all have a prolonged iodine release compared to the IBT, which leads to a burst release. The observed prolonged release also leads to larger inhibition zones during antibacterial tests. Complexing iodine in AUP polymers with or without PVP leads to antimicrobial wound dressings which may hold potential for future application to treat infected wounds.

Deep brain stimulation in Bassen-Kornzweig syndrome: Still effective after 22 years

Introduction

Bassen-Kornzweig syndrome or abetalipoproteinemia is a rare autosomal recessive disorder characterized by a malabsorption of dietary fat and fat-soluble vitamins. This deficiency can lead to a variety of symptoms, including hematological (acanthocytosis, bleeding tendency), neurological (tremor, spinocerebellar ataxia), neuromuscular (myopathy), ophthalmological symptoms (retinitis pigmentosa). The thalamic ventral intermediate nucleus (VIM) is a well-established target for deep brain stimulation (DBS) in the treatment of refractory tremor.

Research question

We evaluated the clinical long-term follow-up (22 years) after VIM-DBS for refractory tremor in abetalipoproteinemia. We also evaluated the adjustments of stimulation settings and medication balance after DBS procedure.

Material and methods

We report a 53-year-old male who suffers from abetalipoproteinemia since the age of 17. He underwent bilateral VIM-DBS to treat his disabling refractory intentional tremor at the age of 31. He still has a very good response to his tremor with limited stimulation adaptations over 22 years. For more than two decades follow-up, the treatment significantly improved his ADL functions and therefore also the QoL.

Discussion and conclusion

The VIM target for DBS in the treatment of refractory tremor has been extensively reported in the literature. Thalamic VIM-DBS is a safe and effective treatment for a severe, refractory tremor as a neurological symptom caused by abetalipoproteinemia. It also highlights the importance of a multidisciplinary follow-up, to adjust and optimize the stimulation/medication balance after VIM-DBS surgery.

Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples

Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide-bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu's parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of <1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate that Ryugu's parent body formed ~2 million years after the beginning of Solar System formation.

Rare earth element identification and quantification in millimetre-sized Ryugu rock fragments from the Hayabusa2 space mission

Millimetre-sized primordial rock fragments originating from asteroid Ryugu were investigated using high energy X-ray fluorescence spectroscopy, providing 2D and 3D elemental distribution and quantitative composition information on the microscopic level. Samples were collected in two phases from two sites on asteroid Ryugu and safely returned to Earth by JAXA's asteroid explorer Hayabusa2, during which time the collected material was stored and maintained free from terrestrial influences, including exposure to Earth's atmosphere. Several grains of interest were identified and further characterised to obtain quantitative information on the rare earth element (REE) content within said grains, following a reference-based and computed-tomography-assisted fundamental parameters quantification approach. Several orders of magnitude REE enrichments compared to the mean CI chondrite composition were found within grains that could be identified as apatite phase. Small enrichment of LREE was found for dolomite grains and slight enrichment or depletion for the general matrices within the Ryugu rock fragments A0055 and C0076, respectively.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1186/s40623-022-01705-3.

Identification of the Calcium, Aluminum, and Magnesium Distribution within Millimeter-Sized Extraterrestrial Materials Using Nonresonant X-ray Raman Spectroscopy in Preparation for the Hayabusa2 Sample Return Mission

The nondestructive investigation of millimeter-sized meteoritic materials is often hindered by self-absorption effects. Using X-ray-based analytical methods, the information depth for many elements (Z < 30) is in the range of up to only a few hundred micrometers, and for low-Z elements (Z < 20), this is reduced even further to only a few tens of micrometers. However, the investigation of these low-Z elements, in particular calcium, aluminum, and magnesium, is of great importance to planetary geologists and cosmochemists, as these elements are regularly used to characterize and identify specific features of interest in extraterrestrial materials, especially primitive chondritic material. In this work, nonresonant inelastic X-ray scattering from core electrons was performed at beamline ID20 of the ESRF in a direct tomography approach in order to visualize these low-Z elements within the millimeter-sized meteoritic samples. The obtained 3D elemental distribution volumes were compared to results from X-ray fluorescence-CT and absorption CT experiments and were found to be in good agreement. Additionally, several regions of interest could be identified within the inelastic scattering volumes, containing information that is not available through the other presented means. As such, the proposed approach presents a valuable tool for the nondestructive investigation of low-Z elemental distributions within millimeter-sized extraterrestrial materials, such as the samples of the Hayabusa2 sample return mission.

Valorization of selenium-enriched sludge and duckweed generated from wastewater as micronutrient biofertilizer

Selenium (Se) is an essential trace element for humans and animals with a narrow window between deficiency and toxicity levels. Application of conventional chemical Se fertilizers to increase the Se content of crops in Se deficient areas could result in environmental contamination due to the fast leaching of inorganic Se. Slow-release Se-enriched biofertilizers produced from wastewater treatment may therefore be beneficial. In this study, the potential of Se-enriched biomaterials (sludge and duckweed) as slow-release Se biofertilizers was evaluated through pot experiments with and without planted green beans (Phaseolus vulgaris). The Se concentration in the bean tissues was 1.1-3.1 times higher when soils were amended with Se-enriched sludge as compared to Se-enriched duckweed. The results proved that the Se released from Se-enriched biomaterials was efficiently transformed to health-beneficial selenoamino acids (e.g., Se-methionine, 76-89%) after being taken up by beans. The Se-enriched sludge, containing mainly elemental Se, is considered as the preferred slow-release Se biofertilizer and an effective Se source to produce Se-enriched crops for Se-deficient populations, as shown by the higher Se bioavailability and lower organic carbon content. This study could offer a theoretical reference to choose an environmental-friendly and sustainable alternative to conventional mineral Se fertilizers for biofortification, avoiding the problem of Se losses by leaching from chemical Se fertilizers while recovering resources from wastewater. This could contribute to the driver for a future circular economy.

Distinct EH domains of the endocytic TPLATE complex confer lipid and protein binding

Clathrin-mediated endocytosis (CME) is the gatekeeper of the plasma membrane. In contrast to animals and yeasts, CME in plants depends on the TPLATE complex (TPC), an evolutionary ancient adaptor complex. However, the mechanistic contribution of the individual TPC subunits to plant CME remains elusive. In this study, we used a multidisciplinary approach to elucidate the structural and functional roles of the evolutionary conserved N-terminal Eps15 homology (EH) domains of the TPC subunit AtEH1/Pan1. By integrating high-resolution structural information obtained by X-ray crystallography and NMR spectroscopy with all-atom molecular dynamics simulations, we provide structural insight into the function of both EH domains. Both domains bind phosphatidic acid with a different strength, and only the second domain binds phosphatidylinositol 4,5-bisphosphate. Unbiased peptidome profiling by mass-spectrometry revealed that the first EH domain preferentially interacts with the double N-terminal NPF motif of a previously unidentified TPC interactor, the integral membrane protein Secretory Carrier Membrane Protein 5 (SCAMP5). Furthermore, we show that AtEH/Pan1 proteins control the internalization of SCAMP5 via this double NPF peptide interaction motif. Collectively, our structural and functional studies reveal distinct but complementary roles of the EH domains of AtEH/Pan1 in plant CME and connect the internalization of SCAMP5 to the TPLATE complex.

Can robot-assisted total knee arthroplasty be a cost-effective procedure? A Markov decision analysis

BACKGROUND

Total knee arthroplasty (TKA) is a frequently and increasingly performed surgery in the treatment of disabling knee osteoarthritis. The rising number of procedures and related revisions pose an increasing economic burden on health care systems. In an attempt to lower the revision rate due to component malalignment and soft tissue imbalance in TKA, robotic assistance (RA) has been introduced in the operating theatre. The primary objective of this study is to provide the results of a theoretical, preliminary cost-effectiveness analysis of RA TKA.

METHODS

A Markov state-transition model was designed to model the health status of sixty-seven-year-old patients in need of TKA due to primary osteoarthritis over a twenty-year period following their knee joint replacement. Transitional probabilities and independent variables were extracted from existing literature.

RESULTS

The value attributed to the utility both for primary and revision surgery has the biggest impact on the ICER, followed by the rate of successful primary surgery and the cost of RA-technology. Only 2.18% of the samples yielded from the probabilistic sensitivity analysis proved to be cost-effective (threshold set at $50000/QALY). A calculated surgical volume of at least 253 cases per robot per year is needed to prove cost-effective taking the predetermined parameter values into account.

CONCLUSION

Based upon transitional probabilities and independent variables derived from existing studies, RA TKA may be cost-effective at a surgical volume of 253 cases per robot per year when compared to conventional TKA.

Investigation of (micro-)meteoritic materials at the new hard X-ray imaging PUMA beamline for heritage sciences

At the French synchrotron facility SOLEIL, a new X-ray imaging facility PUMA (Photons Utilisés pour les Matériaux Anciens) has been made available to scientific communities studying materials from cultural heritage. This new instrument aims to achieve 2D and 3D imaging with microscopic resolution, applying different analytical techniques including X-ray fluorescence spectroscopy (XRF), X-ray absorption spectroscopy (XAS), X-ray diffraction and phase-contrast imaging. In order to discover its capabilities a detailed analytical characterization of this beamline as an analytical and imaging tool is deemed necessary. In this work, (confocal) XRF and XAS analyses are demonstrated using the Seymchan pallasite meteorite and an Antarctic unmelted micrometeorite as case studies. The obtained spatial resolution (2 µm × 3 µm) and sensitivity (detection limits <10 p.p.m. for 1 s acquisition at 18 keV) show that PUMA is a competitive state-of-the-art beamline, providing several high-profile and high-in-demand analytical methods while maintaining applicability towards a wide range of heritage-oriented sciences.

Polycapillary Optics Based Confocal Micro X-ray Fluorescence and X-ray Absorption Spectroscopy Setup at The European Synchrotron Radiation Facility Collaborative Research Group Dutch-Belgian Beamline, BM26A

A novel plug-and-play setup based on polycapillary X-ray optics enables three-dimensional (3D) confocal X-ray fluorescence (XRF) and X-ray absorption spectroscopy down to 8 × 8 × 11 μm³ (17 keV) at the European Synchrotron Radiation Facility Collaborative Research Group Dutch-Belgian Beamline, BM26A. A complete description and analytical characterization is presented, together with two recently performed experimental cases. In Deep Earth diamond São Luiz-Frankfurt am Main 16, an olivine-rich inclusion was mapped with full 3D XRF elemental imaging. The preliminary tests on Iron Gall ink contained in an historical document, a letter from the court of King Philip II of Spain, reveal both the delicate nature of Iron Gall ink and the lack of Fe-Ni chemical bonding.

Spectroscopy as a tool to detect multinuclear Cu(ii)–triethanolamine complexes in aqueous solution

The Evans method, Extended X-ray Absorption Fine Structure (EXAFS) and NMR relaxation dispersion (NMRD) spectroscopy were used to prove the existence of multimeric Cu(ii)–triethanolamine species in aqueous solutions.

Application toward Confocal Full-Field Microscopic X-ray Absorption Near Edge Structure Spectroscopy

Using X-ray absorption near edge structure (XANES) spectroscopy, information on the local chemical structure and oxidation state of an element of interest can be acquired. Conventionally, this information can be obtained in a spatially resolved manner by scanning a sample through a focused X-ray beam. Recently, full-field methods have been developed to obtain direct 2D chemical state information by imaging a large sample area. These methods are usually in transmission mode, thus restricting the use to thin and transmitting samples. Here, a fluorescence method is displayed using an energy-dispersive pnCCD detector, the SLcam, characterized by measurement times far superior to what is generally applicable. Additionally, this method operates in confocal mode, thus providing direct 3D spatially resolved chemical state information from a selected subvolume of a sample, without the need of rotating a sample. The method is applied to two samples: a gold-supported magnesia catalyst (Au/MgO) and a natural diamond containing Fe-rich inclusions. Both samples provide XANES spectra that can be overlapped with reference XANES spectra, allowing this method to be used for fingerprinting and linear combination analysis of known XANES reference compounds.

Sensing the framework state and guest molecules in MIL-53(Al) via the electron paramagnetic resonance spectrum of VIV dopant ions

The EPR spectrum of V^IV dopant ions was used to discriminate different states of MIL-53(Al) and to detect oxygen gas.

Photon Energy Becomes the Third Dimension in Crystallographic Texture Analysis

Conventional analysis of the preferred orientation of crystallites (crystallographic texture) involves X-ray diffraction with area detectors and 2D data output. True 3D, spatially resolved information requires sample rotation in the beam, thus changing the probed volume, which introduces signal smearing and precludes the scanning of complex structures. This obstacle has been overcome by energy-dispersive Laue diffraction. A method has been devised to reach a large portion of reciprocal space and translate the X-ray photon energy into the missing third dimension of space. Carbon fibers and lobster exoskeleton as examples of biomineralized tissue have been analyzed. The major potential of this method lies in its "one-shot" nature and the direct 3D information requiring no previous knowledge of the sample. It allows the texture of large samples with complex substructures to be scanned and opens up the conceptual possibility of following texture changes in situ, for example, during crystallization.

Enhanced gas sorption and breathing properties of the new sulfone functionalized COMOC-2 metal organic framework

A new flexible vanadium based metal organic framework showing a remarkable CO₂ uptake.

Confocal depth-resolved micro-X-ray absorption spectroscopy study of chemically strengthened boroaluminosilicate glasses

A set of chemically strengthened boroaluminosilicate glasses containing 1 mol% Fe₂O₃are here studied using depth-resolved confocal X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopy.

Micro-distribution of uranium in bone after contamination: new insight into its mechanism of accumulation into bone tissue

After internal contamination, uranium rapidly distributes in the body; up to 20 % of the initial dose is retained in the skeleton, where it remains for years. Several studies suggest that uranium has a deleterious effect on the bone cell system, but little is known regarding the mechanisms leading to accumulation of uranium in bone tissue. We have performed synchrotron radiation-based micro-X-ray fluorescence (SR μ-XRF) studies to assess the initial distribution of uranium within cortical and trabecular bones in contaminated rats' femurs at the micrometer scale. This sensitive technique with high spatial resolution is the only method available that can be successfully applied, given the small amount of uranium in bone tissue. Uranium was found preferentially located in calcifying zones in exposed rats and rapidly accumulates in the endosteal and periosteal area of femoral metaphyses, in calcifying cartilage and in recently formed bone tissue along trabecular bone. Furthermore, specific localized areas with high accumulation of uranium were observed in regions identified as micro-vessels and on bone trabeculae. These observations are of high importance in the study of the accumulation of uranium in bone tissue, as the generally proposed passive chemical sorption on the surface of the inorganic part (apatite) of bone tissue cannot account for these results. Our study opens original perspectives in the field of exogenous metal bio-mineralization.

High spectral and spatial resolution X-ray transmission radiography and tomography using a Color X-ray Camera

High resolution X-ray radiography and computed tomography are excellent techniques for non-destructive characterization of an object under investigation at a spatial resolution in the micrometer range. However, as the image contrast depends on both chemical composition and material density, no chemical information is obtained from this data. Furthermore, lab-based measurements are affected by the polychromatic X-ray beam, which results in beam hardening effects. New types of X-ray detectors which provide spectral information on the measured X-ray beam can help to overcome these limitations. In this paper, an energy dispersive CCD detector with high spectral resolution is characterized for use in high resolution radiography and tomography, where a focus is put on the experimental conditions and requirements of both measurement techniques.

Recessive POLG mutations presenting with sensory and ataxic neuropathy in compound heterozygote patients with progressive external ophthalmoplegia

Autosomal recessive progressive external ophthalmoplegia is a mitochondrial disease characterized by accumulation of multiple large-scale deletions of mitochondrial DNA. We previously reported missense mutations in POLG, the gene encoding the mitochondrial DNA polymerase gamma in two nuclear families compatible with autosomal recessive progressive external ophthalmoplegia. Here, we report a novel POLG missense mutation (R627W) in a sporadic patient and we provide genetic support that all these POLG mutations are actually causal and recessive. The novel patient presented with sensory ataxic neuropathy and has the clinical triad of sensory ataxic neuropathy, dysarthria and ophthalmoparesis (SANDO). This is the first finding of a genetic cause of Sensory Ataxic Neuropathy, Dysarthria and Ophthalmoparesis and it implies that this disorder may actually be a variant of autosomal recessive progressive external ophthalmoplegia. Sensory neuropathy is the initial feature in Belgian compound heterozygote autosomal recessive progressive external ophthalmoplegia patients, all carrying the POLG A467T mutation, which occurs at a frequency of 0.6% in the Belgian population.

Glycine antagonist (GV150526) in acute stroke: a multicentre, double-blind placebo-controlled phase II trial

GV150526 is a novel glycine antagonist at the NMDA receptor complex. It is a potent neuroprotective agent in animal models of acute stroke including permanent middle cerebral artery occlusion in the rat. GV150526 was very well tolerated in early human studies. The purpose of this randomised, double-blind, multicentre, placebo-controlled trial was to assess the safety and population pharmacokinetics of GV150526 in patients with a clinical diagnosis of acute stroke. Exploratory assessment of efficacy, quality of life and resource utilisation was also undertaken. Upon clinical diagnosis of acute stroke within 12 h of onset of symptoms, patients were treated with a loading dose of 800 mg GV150526 (or placebo), followed by 5 maintenance doses of 400 mg GV150526 (or placebo) given every 12 h over 3 days. Following observation of asymptomatic hyperbilirubinaemia, the maintenance dose was reduced mid-study to 200 mg. CT/MRI scanning was not mandatory prior to treatment. The study treated 128 patients (38 with GV 800 mg/400 mg, 48 with GV 800 mg/200 mg and 42 with placebo). Fewer patients with mild stroke (NIH scores < or =5) were enrolled in the GV150526-treated groups than in the placebo group (placebo 38%, GV 800 mg/400 mg 18%, GV 800 mg/200 mg 15%). There was also an imbalance in the proportion of patients with haemorrhagic strokes (placebo 5%, GV 800 mg/400 mg 3%, GV 800 mg/200 mg 15%). Mortality at 1 month was unbalanced between treatment groups, being 10, 18 and 17% in the placebo, GV 800 mg/400 mg and GV 800 mg/200 mg groups, respectively (no significant difference). Similarly, adverse events, though consistent with an acute stroke population, appeared more often in the GV 800 mg/200 mg group. Functional outcomes at 1 month also showed imbalances, the percentage of patients with a Barthel Index score of > or =95 at 1 month being 52, 39 and 27% in the placebo, GV 800 mg/400 mg and GV 800 mg/200 mg groups, respectively. These results probably reflect a prognostically significant baseline difference between the groups rather than the effect of GV150526. GV150526 was generally well tolerated in patients with a clinical diagnosis of acute stroke and formal efficacy studies were considered justified.

Reboxetine versus imipramine in the treatment of elderly patients with depressive disorders: a double-blind randomised trial

BACKGROUND

Depression in older people is often unrecognised and untreated or under-treated. Antidepressant treatment may itself exacerbate a pre-existing illness, interact with concomitant medications or produce undesirable cognitive and sedative side effects. Newer antidepressants may offer advantages in terms of a lesser burden of adverse effects.

METHODS

The comparative tolerability of the unique selective noradrenaline reuptake inhibitor (selective NRI) reboxetine (4-6 mg/day; n = 176) and that of imipramine (50-100 mg/day; n = 171) was assessed in an elderly ( > 65 years) cohort of depressed or dysthymic patients in an 8-week, double-blind, multicentre trial. Comparative efficacy was also assessed.

RESULTS

Overall, 68% of patients in the reboxetine group experienced adverse events compared with 71% in the imipramine group. Reboxetine-treated patients were less likely to develop hypotension and related symptoms (7% vs. imipramine 16%) or cardiovascular disorders (12.5% vs. imipramine 21.1%), while those treated with imipramine were less likely to experience insomnia (6.3% vs. 2.9%). Adverse events were more often assessed as related to treatment (43%) and moderate to severe in intensity (73%) with imipramine than with reboxetine (33% and 65%, respectively). Furthermore, there were fewer serious adverse events in the reboxetine-treated group (P = 0.019). The reduction in the Hamilton Rating Scale for Depression (HAM-D) was comparable between the treatment groups in the total population. At the last assessment, the majority of patients in both treatment groups were assessed as normal to borderline or mildly ill using the Clinical Global Impression (CGI) scale. In a subanalysis of the dysthymic patients a modest but significant difference in favour of imipramine was observed for both HAM-D and CGI assessments. This may have been a reflection of a trend towards more severe depressive symptoms at baseline in the reboxetine group.

CONCLUSIONS

Reboxetine is as effective as imipramine in the treatment of depression in elderly patients but is at least as well tolerated with a lower risk of hypotension and related symptoms, fewer serious adverse events, adverse event-related withdrawals and treatment-related adverse events.

Abetalipoproteinemia or Bassen-Kornzweig syndrome. Clinical, biochemical and electrophysiological features of two cases

The clinical, biochemical and electrophysiologic features of two patients with abetalipoproteinemia, a 17 year old boy and his sister of 14, are reported. They are the second and third reports of this disease in Belgium. Diagnosis was made by the Apo-B deficiency in their serum and the normal levels in their parents'. According to other investigators we revealed in both cases deficiency of other apoproteins, indicating, that the metabolic defect affects all classes of plasma lipoproteins. EMG findings showed axonal neuropathy. Somatosensory evoked potentials demonstrated dorsal column dysfunction. Findings were consistent with the known neuropathology of abetalipoproteinemia and of vitamin E deficiency syndromes. The therapeutic role of vitamin E is discussed.