Devenir des patients hospitalisés en soins critiques pour infection à SARS-COV2 : évaluation standardisée des séquelles à 6–9 mois

Introduction

Identifié en Chine en décembre 2019, le Severe Acute Respiratory SyndromeCoronavirus 2 (SARS-COV2) s’est rapidement propagé au niveau mondial. Si les études se sont initialement concentrées sur la prise en charge de la phase aiguë de la COrona VIrus Disease (COVID), l’objectif de ce travail est de s’intéresser aux conséquences à distance d’une hospitalisation pour COVID sévère.

Patients et méthodes

Nous avons réalisé une étude prospective, monocentrique, incluant des patients 6 à 9 mois après leur hospitalisation en soins critiques (soins intensifs ou réanimation) pour une infection confirmée à SARS-COV2. Les patients étaient évalués au cours d’une hospitalisation de jour en médecine interne. L’entretien débutait par un recueil des antécédents du patient, des évènements et des symptômes post-COVID. L’examinateur procédait ensuite à un examen clinique détaillé et un test de marche des 6 minutes (TM6). Les patients réalisaient de manière systématique des explorations fonctionnelles respiratoires (EFR), une tomodensitométrie (TDM) thoracique non injectée, une échographie cardiaque trans-thoracique (ETT), et un bilan biologique complet. Une batterie de tests était réalisée, explorant la qualité de vie et les séquelles psychologiques.

Résultats

Quatre-vingt-six patients, dont 71 (82,6 %) hommes, d’âge médian 65,8 ans (56,7;72,4), ont été évalués dans un délai moyen de 7 mois (min 3,4; max 14,9). L’hypertension artérielle (46,5 %), le diabète (34,9 %) et la dyslipidémie (39,5 %) étaient les antécédents médicaux les plus représentés. Douze (14,0 %) patients avaient une pathologie pulmonaire sous-jacente, principalement une broncho-pneumopathie chronique obstructive (BPCO). L’indice de comorbidités de Charlson médian était de 1 (0,0; 2,0). La durée médiane du séjour en soins critiques était de 10,0 (6,0;17,0) jours. Cinquante-quatre (62,8 %) patients ont eu une ventilation invasive et 67 (77,9 %) patients ont reçu un traitement par corticothérapie. Cinquante-sept (71,3 %) patients ont présenté une asthénie post-COVID, 39 (48,1 %) une faiblesse musculaire, 30 (36,6 %) des arthralgies. Quinze patients ont développé un déséquilibre du diabète et 9 un déséquilibre de la pression artérielle. Dix-sept (21,3 %) patients avaient une distance au TM6 < 80 % de la théorique. Quarante-six patients53,5 %) avaient un score de dyspnée Medical Reaserch Council (MRC) de 0 et 24 (27,9 %) avaient un score MRC de 1. Treize (15,5 %) patients avaient une auscultation anormale à type de crépitants secs des bases. Cinquante-deux (64,2 %) patients ont présenté un déficit de la diffusion du CO défini par une DLCO < 80 % et 16 (19,8 %) avaient une DLCO < 60 %. Le scanner thoracique montrait chez 35 (40,7 %) patients des lésions de verre dépoli et 18 (21,7 %) de la fibrose. Trente-deux patients (37,6 %) avaient un score PHQ-9 significatif pour une dépression, 20 (23,5 %) un score GAD-7 significatif pour un trouble anxieux et 8 (9,4 %) patients avaient un score PCL5 supérieur au seuil évoquant un état de stress post-traumatique. Le niveau de qualité de vie à distance de l’épisode aigu était satisfaisant avec une médiane de l’EQ-5D-3L à 0,89 (0,64;1,00). En analyse univariée, la fibrose sur le scanner de réévaluation et une DLCO < 60 % étaient associées à la durée du séjour en soins critiques et au niveau maximal de CRP pendant l’épisode aigu. En analyse multivariée, la fibrose et la DLCO étaient associées à la durée de séjour. En analyse uni et multivariée, le PHQ-9 et le GAD-7 étaient associés au sexe féminin.

Discussion

À ce jour, rares sont les études qui ont étudié de manière systématisée les séquelles somatiques et psychologiques à long terme de la COVID chez les patients qui ont été pris en charge en soins critiques. Conformément à la littérature, la diminution de la DLCO est l’anomalie la plus fréquemment retrouvée aux EFR, les plages de verre dépoli persistent sur le scanner et des lésions fibrotiques sont retrouvées chez plus d’un patient sur 5 [1], [2]. Ces anomalies contrastent avec une plainte respiratoire modérée et un examen clinique rassurant. Les symptômes généraux (asthénie, faiblesse musculaire et arthralgies) sont au cœur de la plainte fonctionnelle. Les déséquilibres de la tension artérielle et du diabète observés justifient un suivi accru des pathologies chroniques au décours de l’épisode aigu. Enfin, nous avons noté une prévalence plus importante des troubles psychologiques que celles relevées rétrospectivement (dossier informatisé) dans une autre étude [3], renforçant, selon nous, la nécessité d’un dépistage systématique des troubles psychiatriques.

Conclusion

De nombreux patients présentent des séquelles à distance d’une COVID sévère nous incitant à un dépistage systématique afin de proposer une prise en charge adaptée.

Imaging Study by Mass Spectrometry of the Spatial Variation of Cellulose and Hemicellulose Structures in Corn Stalks

The study used mass spectrometry imaging (MSI) to map the distribution of enzymatically degraded cell wall polysaccharides in maize stems for two genotypes and at several stages of development. The context was the production of biofuels, and the overall objective was to better describe the structural determinants of recalcitrance of grasses in bioconversion. The selected genotypes showed contrasting characteristics in bioconversion assays as well as in their lignin deposition pattern. We compared the pattern of cell wall polysaccharide degradation observed by MSI following the enzymatic degradation of tissues with that of lignin deposition. Several enzymes targeting the main families of wall polysaccharides were used. In the early stages of development, cellulose and mixed-linked β-glucans appeared as the main polysaccharides degraded from the walls, while heteroxylan products were barely detected, suggesting subsequent deposition of heteroxylans in the walls. At all stages and for both genotypes, enzymatic degradation occurred preferentially in nonlignified walls for all structural families of polysaccharides studied here. However, our results showed heterogeneity in the distribution of heteroxylan products according to their chemical structure: arabinosylated products were mostly represented in the pith center, while glucuronylated products were found at the pith periphery. The conclusions of our work are in agreement with those of previous studies. The MSI approach presented here is unique and attractive for addressing the histological and biochemical aspects of biomass recalcitrance to conversion, as it allows for a simultaneous interpretation of cell wall degradation and lignification patterns at the scale of an entire stem section.

Quantum size effect on charges and phonons ultrafast dynamics in atomically controlled nanolayers of topological insulators Bi2Te3

Heralded as one of the key elements for next generation spintronics devices, topological insulators (TIs) are now step by step envisioned as nanodevices like charge-to-spin current conversion or as Dirac fermions based nanometer Schottky diode for example. However, reduced to few nanometers, TIs layers exhibit a profound modification of the electronic structure and the consequence of this quantum size effect on the fundamental carriers and phonons ultrafast dynamics has been poorly investigated so far. Here, thanks to a complete study of a set of high quality molecular beam epitaxy grown nanolayers, we report the existence of a critical thickness of around ~6 nm, below which a spectacular reduction of the carrier relaxation time by a factor of ten is found in comparison to bulk Bi2 Te3 In addition, we also evidence an A1g optical phonon mode softening together with the appearance of a thickness dependence of the photoinduced coherent acoustic phonons signals. This drastic evolution of the carriers and phonons dynamics might be due an important electron-phonon coupling evolution due to the quantum confinement. These properties have to be taken into account for future TIs-based spintronic devices.

Electron cooling and debye-waller effect in photoexcited bismuth

By means of first principles calculations, we compute the effective electron-phonon coupling constant G(0) governing the electron cooling in photoexcited bismuth. G(0) strongly increases as a function of electron temperature, which can be traced back to the semimetallic nature of bismuth. We also use a thermodynamical model to compute the time evolution of both electron and lattice temperatures following laser excitation. Thereby, we simulate the time evolution of (1 -1 0), (-2 1 1) and (2 -2 0) Bragg peak intensities measured by Sciaini et al. [Nature (London) 458, 56 (2009)] in femtosecond electron diffraction experiments. The effect of the electron temperature on the Debye-Waller factors through the softening of all optical modes across the whole Brillouin zone turns out to be crucial to reproduce the time evolution of these Bragg peak intensities.

Alteration of glutamate/GABA balance during acute alcohol withdrawal in emergency department: a prospective analysis

AIMS

Animal studies suggest that in alcohol withdrawal the balance of neurotransmitters gamma aminobutyric acid (GABA) and glutamate is altered. To test this in humans, we aimed to measure plasma levels of glutamate, GABA and glutamate/GABA ratio in alcoholic patients presenting with complicated AWS with the same values in non-alcohol abuser/dependent controls and to determine prognostic factors for severe withdrawal.

METHODS

88 patients admitted to the emergency room for acute alcohol intoxication (DSM-IV) were prospectively included. Measurements of GABA and glutamate were performed on admission (Time 1, T1) and after 12 ± 2 h (T2). The experimental group (EG) was composed of 23 patients who presented at T2 with a severe AWS. The control group (CG) consisted of healthy subjects paired with the EG (gender and age). Logistic regression was performed in order to compare associated clinical and biological variables that could predict severe withdrawal.

RESULTS

The concentration of GABA in the EG at T1 was significantly lower than that in the CG. The concentration of glutamate in the EG at T1 was significantly higher than that in the CG. The glutamate/GABA ratio in the EG at T1 was significantly higher than the ratio in the CG. With a multivariate logistic regression model, glutamate level at admission remained the only criterion identified as a predictor of AWS at 12 h.

CONCLUSION

Decreased synthesis of GABA and increased synthesis of glutamate might be related to withdrawal symptoms experienced on brutal cessation of chronic alcohol intake.

Coherent phonon coupling to individual Bloch states in photoexcited bismuth

We investigate the temporal evolution of the electronic states at the bismuth (111) surface by means of time- and angle-resolved photoelectron spectroscopy. The binding energy of bulklike bands oscillates with the frequency of the A(1g) phonon mode, whereas surface states are insensitive to the coherent displacement of the lattice. A strong dependence of the oscillation amplitude on the electronic wave vector is correctly reproduced by ab initio calculations of electron-phonon coupling. Besides these oscillations, all the electronic states also display a photoinduced shift towards higher binding energy whose dynamics follows the evolution of the electronic temperature.

CAGE, RAPS4, RAPS4-QF and AUDIT screening tests for men and women admitted for acute alcohol intoxication to an emergency department: are standard thresholds appropriate?

AIMS

A number of screening instruments are routinely used in Emergency Department (ED) situations to identify alcohol-use disorders (AUD). We wished to study the psychometric features, particularly concerning optimal thresholds scores (TSs), of four assessment scales frequently used to screen for abuse and/or dependence, the cut-down annoyed guilty eye-opener (CAGE), Rapid Alcohol Problem Screen 4 (RAPS4), RAPS4-quantity-frequency and AUD Identification Test (AUDIT) questionnaires, particularly in the sub-group of people admitted for acute alcohol intoxication (AAI).

METHODS

All included patients [AAI admitted to ED (blood alcohol level ≥0.8 g/l)] were assessed by the four scales, and with a gold standard (alcohol dependence/abuse section of the Mini International Neuropsychiatric Interview), to determine AUD status. To investigate the TSs of the scales, we used Youden's index, efficiency, receiver operating characteristic (ROC) curve techniques and quality ROC curve technique for optimized TS (indices of quality).

RESULTS

A total of 164 persons (122 males, 42 females) were included in the study. Nineteen (11.60%) were identified as alcohol abusers alone and 128 (78.1%) as alcohol dependents (DSM-IV). Results suggest a statistically significant difference between men and women (P < 0.05) in performance of the screening tests RAPS4 (≥1) and CAGE (≥2) for detecting abuse. Also, in this population, we show an increase in TSs of RAPS4 (≥2) and CAGE (≥3) for detecting dependence compared with those typically accepted in non-intoxicated individuals. The AUDIT test demonstrates good performance for detecting alcohol abuse and/or alcohol-dependent patients (≥7 for women and ≥12 for men) and for distinguishing alcohol dependence (≥11 for women and ≥14 for men) from other conditions.

CONCLUSION

Our study underscores for the first time the need to adapt, taking into account gender, the thresholds of tests typically used for detection of abuse and dependence in this population.

Entropy driven atomic motion in laser-excited bismuth

We introduce a thermodynamical model based on the two-temperature approach in order to fully understand the dynamics of the coherent A(1g) phonon in laser-excited bismuth. Using this model, we simulate the time evolution of (111) Bragg peak intensities measured by Fritz et al. [Science 315, 633 (2007)] in femtosecond x-ray diffraction experiments performed on a bismuth film for different laser fluences. The agreement between theoretical and experimental results is striking not only because we use fluences very close to the experimental ones but also because most of the model parameters are obtained from ab initio calculations performed for different electron temperatures.

Multipole electron-density modelling of synchrotron powder diffraction data: the case of diamond

Accurate structure factors are extracted from synchrotron powder diffraction data measured on crystalline diamond based on a novel multipole model division of overlapping reflection intensities. The approach limits the spherical-atom bias in structure factors extracted from overlapping powder data using conventional spherical-atom Rietveld refinement. The structure factors are subsequently used for multipole electron-density modelling, and both the structure factors and the derived density are compared with results from ab initio theoretical calculations. Overall, excellent agreement is obtained between experiment and theory, and the study therefore demonstrates that synchrotron powder diffraction can indeed provide accurate structure-factor values based on data measured in minutes with limited sample preparation. Thus, potential systematic errors such as extinction and twinning commonly encountered in single-crystal studies of small-unit-cell inorganic structures can be overcome with synchrotron powder diffraction. It is shown that the standard Hansen-Coppens multipole model is not flexible enough to fit the static theoretical structure factors, whereas fitting of thermally smeared structure factors has much lower residuals. If thermally smeared structure factors (experimental or theoretical) are fitted with a slightly wrong radial model (s(2)p(2) instead of sp(3)) the radial scaling parameters (kappa' parameters) are found to be inadequate and the ;error' is absorbed into the atomic displacement parameter. This directly exposes a correlation between electron density and thermal parameters even for a light atom such as carbon, and it also underlines that in organic systems proper deconvolution of thermal motion is important for obtaining correct static electron densities.

Mutation in the melanocortin 1 receptor is associated with amber colour in the Norwegian Forest Cat

Amber (previously called X-Colour) is a yellow recessive coat colour observed in the Norwegian Forest Cat (NFC) population and apparently absent in other cat breeds. Until now, there has never been any scientific evidence of yellow recessive mutation (e) reported in the extension gene in Felidae. We sequenced the complete coding sequence region for the melanocortin 1 receptor in 12 amber, three carriers, two wild-type NFCs, one wild-type European Shorthair and two 'golden' Siberian cats and identified two single nucleotide polymorphisms (SNPs): a non-synonymous (FM180571: c.250G>A) and a synonymous (FM180571: c.840T>C) mutation. The c.250G>A SNP, further genotyped on 56 cats using PCR-RFLP, is associated with amber colour and only present in the amber cat lineages. It replaced an aspartic acid with a neutral polar asparagine in the second transmembrane helix (p.Asp84Asn), a position where e mutations have already been described. Three-dimensional models were built and showed electrostatic potential modification in the mutant receptor. With these results and together with those in the scientific literature, we can conclude that amber colour in NFCs is caused by a single MC1R allele called e, which has never been documented.

Monocytes downregulate the early stage of collagen-induced platelet activation by a PECAM-1-dependent mechanism

BACKGROUND

Blood vessel damage results in exposure of the subendothelial matrix, to which platelets adhere. Monocytes are recruited and activated at the site of injury.

OBJECTIVES

Here we studied the effect of monocytes on platelet activation induced by exposure to fibrillar collagen.

METHODS

Washed platelets and isolated monocytes (100/1) were coincubated with type I collagen in static adhesion conditions or in suspension. Platelet activation was assessed by measuring RANTES production and alpha-granule secretion. Platelet adherence on immobilized collagen was analyzed by fluorescence confocal microscopy. Cell-cell contacts were prevented by incubating platelets and monocytes in transwell coculture dishes. Experiments were also performed in the presence of soluble recombinant platelet endothelial cell adhesion molecule-1 (PECAM-1) or of antibodies to PECAM-1.

RESULTS

Unexpectedly, unstimulated monocytes limited the initial phase of platelet activation by fibrillar collagen. In adhesion conditions, monocytes reduced the secretion by platelets of the inflammatory chemokine RANTES and of beta-thromboglobulin and the formation of platelet aggregates. The inhibitory effect of monocytes on platelet activation required direct cell-cell contacts between platelets and monocytes. Monocytes also inhibited collagen-induced platelet activation in suspension conditions as assessed by the reduction of P-selectin exposure and RANTES secretion. A recovery of platelet responses was observed in the presence of soluble PECAM-1 and of PECAM-1.3 Fab, indicating that PECAM-1 is involved in monocyte-triggered downregulation of platelet reactivity.

CONCLUSIONS

Our data provide the first evidence that unstimulated monocytes limit the initial phase of platelet activation by collagen via a mechanism that is, at least in part, PECAM-1-dependent.

Apport de la photothérapie dynamique dans la qualité de vie des patients atteints de dégénérescence maculaire exsudative

PURPOSE

To analyze the benefit of photodynamic therapy in terms of quality of life in patients with wet age-related macular degeneration.

METHODS

A retrospective study was conducted on 33 patients with subretinal neovascularization receiving visual rehabilitation in a low vision clinic (ARAMAV, Nîmes) in southern France. Twenty had been treated with photodynamic therapy (PDT group) and 13 had not (non-PDT group). In the non-PDT group, the patients had been treated with thermal photocoagulation, transpupillary thermotherapy, or external radiotherapy, or had not received any treatment. Visual acuity, reading speed, reading endurance, and quality of life were compared. Two quality-of-life scales were employed: the VF-14 and NEI-VFQ-25.

RESULTS

A significant difference between the two groups in terms of quality of life was observed. The VF-14 score (p<0.01) and two parameters (near activities and distant activities) of the NEI VFQ-25 were significantly higher (both p<0.01) in the PDT group. Visual acuity, reading speed, and reading endurance were similar in both groups.

CONCLUSION

Although no difference in terms of functional parameters was observed, photodynamic therapy could preserve the central retina and thus enable a better use of the residual visual function, which could explain the better quality of life perceived by the patients in the PDT group.

Huge excitonic effects in layered hexagonal boron nitride

The all-electron GW approximation energy band gap of bulk hexagonal boron nitride is shown to be of indirect type. The resulting computed in-plane polarized optical spectrum, obtained by solving the Bethe-Salpeter equation for the electron-hole two-particle Green function, is in excellent agreement with experiment and has a strong anisotropy compared to out-of-plane polarized spectrum. A detailed analysis of the excitonic structures within the band gap shows that the low-lying excitons belong to the Frenkel class and are tightly confined within the layers. The calculated exciton binding energy is much larger than that obtained by Watanabe et al. [Nat. Mater. 3, 404 (2004).] based on a Wannier model assuming h-BN to be a direct-band-gap semiconductor.

Efficience des critères vidéokératographiques quantitatifs dans l’analyse familiale de patients atteints de kératocône

AIM

We statistically assessed the videokeratographic data obtained from families with keratoconus in order to determine reliable criteria for detecting keratoconus suspects.

MATERIAL AND METHODS

Fourteen keratoconus patients from 12 families were enlisted. We investigated 55 relatives (110 eyes). Standard videokeratographic data were obtained by screening 30 individuals (60 eyes) with clinically normal eyes, with no history of ocular disorders, contact lens wear, or keratoconus individuals in their family. Videokeratographic qualitative and quantitative analyses were performed on every subject. The videokeratographic threshold values obtained from the control group were used as a reference.

RESULTS

Two criteria based on the Klyce/Maeda indices proved their statistical significance in detecting keratoconus suspects. When considering the significant criteria ascertained by the statistical analysis, building pedigrees favored the autosomal dominant mode of inheritance. Two of the pedigrees corresponded to either a recessive mode of transmission or the potential occurrence of a de novo mutation.

CONCLUSION

We have determined videokeratographic criteria of statistical significance for detecting keratoconus suspects. The knowledge of the status of each member of families with keratoconus is a prerequisite to performing genetic linkage analyses, which may allow a precise locus linked with this disorder to be refined.

[Optic nerve sheath decompression in optic neuropathy complicating idiopathic intracranial hypertension: a new focus]

Optic nerve sheath decompression is a surgical procedure only used in optic neuropathy complicating idiopathic intracranial hypertension. We describe this technique and compare it with the classic technique of cerebrospinal liquid derivation. Several points contrast optic nerve sheath decompression and cerebrospinal fluid derivation: there is no biomaterial, it is limited to the orbital area, and intracranial pressure remains unchanged. The complications are different, yet analysis of the literature shows the same efficacy in terms of visual function. We recommend a practical management of optic neuropathy complicating idiopathic intracranial hypertension, depending on the functional severity and the therapeutic efficacy. The surgical indication should only concern serious optic neuropathy not responding to medical therapy, with the choice of the surgical technique belonging to the surgeon.

[Amiodarone and disk edema: physiopathological debate based on a case report]

We describe the case of a patient showing bilateral disk edema linked to amiodarone intake and discuss the controversial physiopathology of this condition. The clinical investigation as well as the follow-up of this case established the diagnosis of amiodarone-induced papillary disease. Pseudotumor cerebri and alteration of optic disk vascularization were also involved in the optic neuropathy displayed by this patient. This case illustrates the multifactorial character of this entity whose heterogeneous clinical expression is linked both to the direct toxic effect of amiodarone and the likely occurrence of pseudotumor cerebri, as well as to the disorders for which this type of medication is frequently used. Amiodarone is widely used and its implication as a cause of disk swelling should be systematically investigated.

[Spontaneous hyphema caused by Ginkgo biloba extract]

We report the first case of a patient in whom Ginkgo biloba extract proved to be the unique cause of spontaneous hyphema. Extensive ophthalmological and biological investigations were undertaken in order to assess the role of Ginkgo biloba: platelet numbering, hemostasis factors, Willebrand antigen, ristocetin cofactor, platelet glycoprotein immunophenotyping, glycoprotein expression after activation by thrombin, inflammatory markers, B-scan ultrasonography, and fluorescent iridography. No putative causes of hyphema were recorded other than Gingko biloba intake. The bleeding originated from the 12-o'clock position of the iris margin. Anamnesis identified Ginkgo biloba extract ingestion from 2 weeks before the appearance of the patient's visual trouble. Ginkgo biloba intake was stopped and the hemorrhage resolved with no recurrence during the 18 months of follow-up. Ginkgo biloba is known for platelet inhibition and is extensively used in the elderly because of its beneficial effects as a vascular protector. The clinical progression of the present case strongly suggests that Ginkgo biloba may cause hemorrhage and hyphema, even in the absence of any other predisposing factor.

[Clinically isolated Morning glory syndrome]

The Morning glory syndrome is an uncommon congenital optic disk anomaly. It is characterized by a funnel-shaped and enlarged dysplasic optic disk with white tissue, and retinal vessels arising from the periphery of the disk and running an abnormally straight course over the peripapillary retina. We report here the case of a 7-year-old girl with a delayed diagnosis of Morning glory syndrome discovered at a regular examination that showed amblyopia. The optic disk anomaly was isolated. The search for other associated morphological and/or functional abnormalities is mandatory (retinal and/or cerebral malformation, frontonasal dysplasia, endocrine irregularities, neurofibromatosis type 2). Periodic ophthalmological examinations are recommended due to the frequency of retinal detachment.

Retinal dystrophies caused by mutations in RPE65: assessment of visual functions

AIMS

To characterise the disease in patients with mutations in RPE65.

METHODS

Individuals from two families were studied clinically.

RESULTS

13 and 20 year old compound heterozygote individuals from one family with R234X and 1121delA mutations showed nystagmus, macular dystrophy and low contrasted spots in the fundus. Some heterozygotes had macular drusen. A 40 year old compound heterozygote individual from another family with L22P and H68Y mutations had few bone spicule pigment deposits and macular atrophy.

CONCLUSION

Compound heterozygote individuals had severe rod-cone dystrophies featuring few pigment deposits in the fundus, pigment epithelium atrophy, and early involvement of the macula, with variations in severity leading to the diagnosis of Leber's congenital amaurosis or retinitis pigmentosa. Macular drusen in heterozygotes carrying a null allele may reflect the decreased capacity in the RPE65 function.

Segregation of a mutation in CNGB1 encoding the beta-subunit of the rod cGMP-gated channel in a family with autosomal recessive retinitis pigmentosa

Retinitis pigmentosa (RP) is a clinically and genetically heterogeneous group of retinal diseases leading to blindness. By performing full genome linkage analysis in a consanguineous French family affected with severe autosomal recessive RP, we have excluded linkage to known loci involved in RP and mapped a novel locus to chromosome 16q13-q21 (Zmax=2.83 at theta=0 at the D16S3089 locus). Two candidate genes KIFC3 and CNGB1 mapping to this critical interval have been screened for mutations. The CNGB1 gene, which encodes the beta-subunit of the rod cGMP-gated channel, is mutated in the family presented in this study.

[Molecular genetics of pigmentary retinopathies: identification of mutations in CHM, RDS, RHO, RPE65, USH2A and XLRS1 genes]

PURPOSE

To evaluate the occurrence and inheritance of various types of pigmentary retinopathy in patients followed at the outpatient clinic in the university hospital, Montpellier, France. To characterize genes and mutations causing these conditions.

METHODS

Ophthalmic examination and various visual tests were performed. Mutations were sought from genomic DNA by PCR amplification of exons associated with single-strand conformation analysis and/or direct sequencing.

RESULTS

Among 315 patients over an 8-year period, cases of retinitis pigmentosa (63.2%), Usher's syndrome (10.2%), Stargardt's disease (5.4%), choroideremia (3.2%), Leber's congenital amaurosis (3.2%), congenital stationary night blindness (2.9%), cone dystrophy (2.5%), dominant optic atrophy (1.9%), X-linked juvenile retinoschisis (1.6%), Best's disease (1.6%), and others (4.3%) were diagnosed. In retinitis pigmentosa, inheritance could be determined in 54.2% of the cases including dominant autosomic (26.6%), recessive autosomic (22.6%), and X-linked cases (5%) while it could not be confirmed in 45.7% of the cases (simplex cases in the majority). For the 6 examined genes, mutations were found in 22 out of 182 propositus (12.1%). Analysis of phenotype-genotype correlations indicates that in retinitis pigmentosa, RDS is more frequently associated with macular involvement and retinal flecks, RHO with regional disease, and RPE65 with the great severity of the disease with some cases of Leber's congenital amaurosis.

CONCLUSIONS

Identification of genes may help in diagnosis and in genetic counseling, especially in simplex cases with retinitis pigmentosa. In this latter condition, molecular diagnosis will be necessary to rationalize future treatments.

[Ocular toxocariasis. Value of local immunodiagnosis]

Toxocara canis is a nematode that may be involved in human ocular toxocariasis. Specific immunotesting is of importance but may be negative as toxocara antigens may localize exclusively in vitreous humor. We report here the case of one patient with optic disc toxocariasis granuloma negative for toxocara canis immunodiagnostic on serum. Clinical diagnosis was confirmed by toxocara canis specific enzyme-linked immunosorbent assay (ELISA) on aqueous humor showing elevated titers of antibodies. Systemic steroids associated to specific treatment of toxocariasis were initiated. Follow-up displayed regression of uveitis but development of vitreous bands leading to posterior retinal detachment. Toxocara posterior granuloma is of poor visual prognosis. Moreover, diagnosis may be of late setting, as clinical features are often unrecognized and specific immunodiagnostic on serum negative. Specific immunotesting on aqueous humor is of particular importance to rule out severe clinical differential diagnosis such as retinoblastoma in children. Ultrasound biomicroscopy (UBM) seems to be specific and sensitive in patients with a presumed diagnosis of peripheral toxocariasis. Granuloma surgery appears to yield good clinical results and allows histological confirmation of the diagnosis.

Keratographic analysis of a family with keratoconus in identical twins

We screened family members of monozygotic twins with keratoconus to search for a corneal thinning disorder using clinical, videokeratographic, and pachymetric analyses. The parents had bilateral astigmatism of a symmetric bow-tie pattern with normal videokeratographic and pachymetric indices. The 8-year-old sister had slightly asymmetric astigmatism in both eyes with normal pachymetry values. No family member was suspected of a corneal thinning disorder. We discuss the mode of inheritance of keratoconus in this family.

Nuclear gene OPA1, encoding a mitochondrial dynamin-related protein, is mutated in dominant optic atrophy

Optic atrophy type 1 (OPA1, MIM 165500) is a dominantly inherited optic neuropathy occurring in 1 in 50,000 individuals that features progressive loss in visual acuity leading, in many cases, to legal blindness. Phenotypic variations and loss of retinal ganglion cells, as found in Leber hereditary optic neuropathy (LHON), have suggested possible mitochondrial impairment. The OPA1 gene has been localized to 3q28-q29 (refs 13-19). We describe here a nuclear gene, OPA1, that maps within the candidate region and encodes a dynamin-related protein localized to mitochondria. We found four different OPA1 mutations, including frameshift and missense mutations, to segregate with the disease, demonstrating a role for mitochondria in retinal ganglion cell pathophysiology.

In vitro creation of amyloid fibrils from native and Arg124Cys mutated betaIGH3((110-131)) peptides, and its relevance for lattice corneal amyloid dystrophy type I

BetaIGH3 protein has been recently involved in the pathogenesis of blinding corneal diseases, some of which have characteristic amyloid corneal deposits. The 124 codon of the betaig-h3 gene seems to be crucial for the amyloidogenicity of the protein product. We presently report an in vitro system that reproducibly forms amyloid fibrils from betaIGH3((110-131)) derived peptides. We also assessed the differences in fibril formation of two 22-amino acid peptides centered on the 124 residue: the native form and the Arg124Cys peptide (mutation linked to lattice corneal amyloid dystrophy type 1). After dialysis of Arg124Cys peptide against PBS 1/15 M pH 7.4 for 72 hours, Congo red staining and electron microscopy demonstrated the presence of abundant material fulfilling the criteria of amyloid. Quantitative analysis with thioflavine T fluorescence studies confirmed the high capacity of Arg124Cys peptide to form amyloid fibrils when compared to the native form.

Keratectasia Induced by Laser in situ Keratomileusis in Keratoconus

PURPOSE

Corneal thinning disorders weaken the mechanical strength of affected corneas, suggesting that photorefractive procedures may be contraindicated in keratoconus. Few cases have been reported to confirm this hypothesis.

METHODS

A 45-year-old man had two laser in situ keratomileusis (LASIK) procedures and one photorefractive keratectomy (PRK) performed on his left eye, and three LASIK procedures on his right eye. After these surgeries, a dramatic corneal ectasia and grade III haze occurred in both eyes, with a clinical diagnosis of keratoconus. The changes in his corneas were followed with videokeratography and slit-lamp microscopy.

RESULTS

Preoperative videokeratograph of both eyes suggested keratoconus. After multiple refractive procedures, the best spectacle-corrected visual acuity was as low as 20/1200 bilaterally. Both eyes displayed dramatic corneal protrusion with corneal scarring.

CONCLUSIONS

This case emphasizes the need for preoperative corneal thickness measurement and detailed analysis of videokeratographs. Thinning corneal disorders such as keratoconus, keratoconus suspects, or pellucid marginal degeneration are a contraindication for excimer laser ablative refractive procedures.

BIGH3 exon 14 mutations lead to intermediate type I/IIIA of lattice corneal dystrophies

PURPOSE

To screen the BIGH3 gene in three unrelated families with lattice corneal dystrophy (LCD), two of which disclosed a particular phenotype.

METHODS

Genomic DNA was extracted from peripheral leukocytes of the affected patients and their family members. The entire coding sequence of the BIGH3 gene was screened for mutations by means of transcript analysis on total RNA isolated from peripheral leukocytes by reverse transcription-polymerase chain reaction performed with primers designed for this study. Each mutation was confirmed at the genomic level, by using published primers.

RESULTS

One family that had a typical form of LCD, had the described R124C mutation in the BIGH3 gene. Two families with atypical forms of LCD were negative for the previously known mutations of the gene. Direct sequencing of the BIGH3 mRNA in the latter two families allowed us to identify two mutations located in exon 14. They consist of a 9-bp insertion at position 18851886 and one missense mutation at position 1877 of the BIGH3 gene. Three new polymorphisms were also observed.

CONCLUSIONS

Two mutations different from those linked to LCD have been found in clinically distinguishable forms of this disease, intermediate between LCDs types I and IIIA. The DNA segment comprising both alterations normally encodes for a highly conserved region of the fourth internal domain of the Betaig-h3 protein, suggesting that this region may be of functional and/or structural importance. The identification of new mutations by screening of the complete BIGH3 gene and the comparative analysis of the induced modifications in betaig-h3 protein should shed light in the understanding of the molecular mechanisms underlying LCDs resulting from mutations in the BIGH3 gene, and may help to explain their phenotypic heterogeneity.

A comparison of topical mequitazine and disodium cromoglycate in allergic conjunctivitis induced by a specific conjunctival provocation test

PURPOSE

Twenty-two people with a history of grass pollen allergic conjunctivitis were enrolled outside the pollen season in this study to compare the efficacy of 0.05% mequitazine eyedrops with topical 2% disodium cromoglycate.

METHODS

This randomized, double-blind study compared right and left eyes. Subjects received 2% disodium cromoglycate eyedrops in one eye and mequitazine vehicle in the fellow eye 4 times daily for 4 days. For the last instillation, mequitazine vehicle was replaced by one drop of 0.05% mequitazine and 15 min later a conjunctival provocation test (CPT) with grass pollen was performed.

RESULTS

The sum of the scores for hyperemia and itching, and total composite score were lower after 0.05% mequitazine than after 2% disodium cromoglycate (p < 0.0001 in each case). The allergen threshold dose which elicited a positive allergic response was higher in the mequitazine group (p < 0.001). Both treatments showed good tolerance upon instillation. No adverse events related to study treatment occurred.

CONCLUSIONS

These results demonstrate the superior efficacy of a single drop of 0.05% mequitazine 15 min before CPT compared with 2% disodium cromoglycate 4 times daily for 4 days.

Molecular analysis of the rhodopsin gene in southern France: identification of the first duplication responsible for retinitis pigmentosa, c.998999ins4

PURPOSE

Mutations in the gene encoding rhodopsin, the visual pigment in rod photoreceptors, were shown to be the most common cause of autosomal retinitis pigmentosa (RP). In order to determine the prevalence of rhodopsin alterations in southern French populations, we examined 52 unrelated patients/families with autosomal dominant RP (adRP=29), RP simplex (6), or unclassified RP (17).

METHODS

The full coding and flanking sequences of the rhodopsin (RHO) gene were scanned using an improved DGGE (denaturing gradient gel electrophoresis) assay, followed by sequencing of abnormal fragments.

RESULTS

This study revealed three RHO mutations in patients with adRP (G106R, R135W, and c.998999ins4) and a number of frequent or rare polymorphisms. No disease-causing sequence variation was found in simplex and unclassified RP pedigrees. Mutation c.998999ins4 has not been previously reported, and appears as the first duplication identified so far in the RHO gene. This frameshift mutation, which is associated with a severe RP, alters the carboxy terminus and predicts a 353-amino acid mutant rhodopsin instead of 348.

DISCUSSION

Our study demonstrates that rhodopsin mutations are responsible for only 10.3% of adRP in French populations living in the Mediterranean area in contrast to the 25-35% reported in other populations.

[Intra-orbital decompression of the optic nerve by opening the peri-optic meninges in the treatment of severe optic neuropathies complicating benign intracranial hypertension]

Papilledema from benign intracranial hypertension can cause severe loss of visual acuity and visual field, with an optic neuropathy. We report a study of 5 patients with benign intracranial hypertension, and severe visual loss (visual field loss and visual acuity reduced to 1/10 or less) not improved by medical therapy (acetazolamide). We performed unilateral orbital decompression of the optic nerve sheath. No major operative complication was noted. Follow-up ranged from 11 months to 23 months, with an average of sixteen months. Visual function improvement was noted within 3 months after operation in 4 patients (for 2 eyes on the surgical side improvement of 2/10 and 5/10, for 3 eyes on the opposite surgical side average improvement of 4.6/10). The other patient showed improvement, but no significant. Optic nerve sheath decompression in benign intracranial hypertension seems to be a safe procedure and a therapeutic option in the management of raised intracranial pressure complicated by optic neuropathy with severe visual loss.

Autosomal recessive retinal dystrophy associated with two novel mutations in the RPE65 gene

Retinal dystrophies are a complex set of hereditary diseases of the retina that result in the degeneration of photoreceptors. Recent studies have shown that mutations in RPE65, a gene that codes for a retinal pigment epithelium (RPE)-specific protein thought to be involved in the 11-cis-retinoid metabolism, a key process in vision, cause severe, early onset retinal dystrophy. We describe two novel missense RPE65 mutations, L22P and H68Y, in a compound heterozygote with autosomal recessive retinal dystrophy. The relatively mild phenotype associated with these mutations suggests a possible link between the severity of the disease and the type of mutations in the RPE65 gene.

Rod and cone function in the Nougaret form of stationary night blindness

BACKGROUND

Recently, a mutation (Gly38Asp) was identified in the alpha subunit of rod transducin in members of the Nougaret pedigree affected with dominantly inherited stationary night blindness.

OBJECTIVE

To evaluate retinal function in patients with the Gly38Asp gene defect.

DESIGN

Ocular examinations, including specialized measures of rod and cone function.

SETTING

A clinical research facility in Boston, Mass.

PATIENTS

A father (aged 48 years) and son (aged 25 years) with the Gly38Asp mutation.

MAIN OUTCOME MEASURES

Psychophysical thresholds to white and narrowband lights and full-field electroretinographic (ERG) responses.

RESULTS

Both patients showed dark-adapted thresholds to white light that were elevated approximately 2 log-units across the retina. Spectral sensitivity testing revealed thresholds that seemed to be governed mostly by rods. Although both patients' dark-adapted ERG responses to a dim blue flash were nondetectable, their dark-adapted ERGs to a white flash showed an a-wave with cone and rod components and a b-wave amplitude larger than what could have been generated by cone function alone. Rod ERGs to bright blue flashes had subnormal, but detectable, amplitudes that seemed to result from a profound reduction in sensitivity. The patients also showed loss of a cone subcomponent in the dark-adapted response to a red flash. The abnormal dark-adapted ERG responses of the patients could be simulated in the ERG responses of normal subjects tested with blue, white, and red flashes presented in the presence of a mesopic background.

CONCLUSIONS

Although the Nougaret form of stationary night blindness has been cited as a prototype of absent rod function with normal cone function, our findings, based on the genealogically and genotypically documented descendants of Jean Nougaret, show that rod function is present, although subnormal, and that there is slight impairment of cone function. The data also suggest that these abnormalities can be simulated by light-adapting the normal retina, compatible with the proposal that the rod transducin encoded by the mutant gene is constitutively active and that the night blindness results from partial desensitization of rods caused by the constitutive activity.

[Update on a diagnostic test for choroideremia: the protein truncation test (PTT)]

PURPOSE

The aim of this study was to define the RT-PCR-PTT parameters for CHM gene analysis and to evaluate its interest as a method for CHM mutation screening.

METHODS

The entire CHM coding region was reversed-transcribed in three overlapping cDNA segments (RT-PCR) which were amplified and further analyzed by PTT after in vitro transcription/translation.

RESULTS

This strategy enabled us to detect a truncated peptide in each of the 6 unrelated patients from southern France who were investigated. The mutation was further characterized by direct sequencing of the RT-PCR product.

CONCLUSION

In CHM gene, all conditions are present to make the RT-PCR-PTT strategy the method of choice for mutation screening. As a result of the simplified protocol described in this study, the families of the patients could benefit from accurate carrier-status assessment.

[Clinical features and genetic analysis in a family with X-linked incomplete congenital stationary night blindness (CSNBi)]

PURPOSE

We describe particular clinical features in a three-generation family with X-linked CSNBi and present the genetic analysis.

METHOD

The diagnosis of CSNBi was established on clinical and electrophysiological criteria. Polymorphic DNA markers of the Xp region were analyzed by fluorescent polymerase chain reaction.

RESULTS

Clinical findings evidenced an atypical association of both myopia and hyperopia in the same brotherhood. The most interesting feature in this family was the observation of major worsening of the clinical shape between the first and the third generation of affected individuals. DNA analysis did not show significant linkage between the disease and markers of the Xp11-p21 region. Southern analysis did not show expansion of trinucleotide repeat CAG/CTG and CCG/CGG over the three generation.

CONCLUSION

Haplotypic analysis together with clinical observations allow to exclude the existence of a myopia gene closely linked to the CSNB2 locus. The clinical anticipation observed in this family does not seem to be linked with trinucleotide repeat expansion CAG/CTG or CCG/CGG.