The effect of genotype on the natural history of eIF2B-related leukodystrophies

BACKGROUND

Recessive mutations in the five eucaryotic initiation factor 2B (eIF2B) subunits have been found in leukodystrophies of variable age at onset and severity.

OBJECTIVES

To evaluate the clinical spectrum of eIF2B-related disorders and search for a phenotype-genotype correlation.

METHODS

Ninety-three individuals (78 families) with an undetermined leukodystrophy were selected on MRI-based criteria of childhood ataxia with central hypomyelination/vanishing white matter (CACH/VWM) for EIF2B genes analysis.

RESULTS

Eighty-nine percent of individuals with MRI criteria of CACH/VWM have a mutation in one of the eIF2B beta to epsilon subunits. For 83 individuals (68 families), 46 distinct mutations (90% missense) in four of the five eIF2B subunits (beta, gamma, delta, epsilon) were identified. Sixty-four percent were in the epsilon subunit, a R113H substitution was found in 71% of eIF2B epsilon-mutated families. A large clinical spectrum was observed from rapidly fatal infantile to asymptomatic adult forms. Disease severity was correlated with age at onset (p < 0.0001) but not with the type of the mutated subunit nor with the position of the mutation within the protein. Mutations R113H in the epsilon subunit and E213G in the beta subunit were significantly associated with milder forms.

CONCLUSIONS

The degree of eIF2B dysfunction, which is involved in the regulation of protein synthesis during cellular stress, may play a role in the clinical expression of eIF2B-related disorders.

Alexander disease: putative mechanisms of an astrocytic encephalopathy

Alexander disease (AXD) is the first primary astrocytic disorder. This encephalopathy is caused by dominant mutations in the glial fibrillary acidic protein (GFAP) gene, encoding the main intermediate filament of astrocyte. Pathologically, this neurodegenerative disease is characterised by dystrophic astrocytes containing intermediate filament aggregates associated with myelin abnormalities. More than 20 GFAP mutations have been reported. Many of them cluster in highly conserved regions between several intermediate filaments. Contrary to other intermediate filament-related diseases, AXD seems to be the consequence of a toxic gain of function induced by aggregates. This is supported by the phenotype of mice overexpressing human GFAP. Nevertheless, GFAP null mice display myelin abnormalities and blood-brain barrier dysfunction that are present in AXD. Given the pivotal role of astrocytes in brain physiology, there are many possibilities for astrocytes to dysfunction and to impair the functions of other cells. Physiopathological hypotheses are discussed in the frame of AXD.

Endovascular repair of descending thoracic aortic aneurysm via midsternotomy and without extracorporeal circulation

A 68-year-old man with peripheral vascular disease and associated risk factors, was diagnosed by CT-scan and aortography with an atherosclerotic descending thoracic aortic aneurysm. The patient was treated by successful endovascular grafting of the aneurysm using a midsternotomy incision and the insertion of a thoracic stent-graft through a T-Dacron tube sutured in the ascending aorta, without the aid of cardiopulmonary bypass.

Genetic heterogeneity of megalencephalic leukoencephalopathy and subcortical cysts

Reported are the clinical, neuroradiologic, and molecular findings in 18 patients with megalencephalic leukoencephalopathy and subcortical cysts (MLC) syndrome. Marked clinical intrafamilial and interfamilial variability in mutation-proven cases was found. A broad spectrum of pathogenetic mutations (missense, splice site, insertion, and deletions) were identified in the MLC1 gene, enlarging the spectrum of allelic variants without a straightforward genotype-phenotype correlation. Five patients did not harbor mutations in MLC1, supporting the existence of at least one other MLC locus.

Cyclic deformation fatigue behaviour of Ti6Al4V thermochemically nitrided for articular prostheses

Titanium and its alloys have many attractive properties including high specific strength, low density, and excellent corrosion resistance. Titanium and the Ti6Al4V alloy have long been recognized as materials with high biocompatibility. These properties have led to the use of these materials in biomedical applications. Despite these advantages, the lack of good wear resistance makes the use of titanium and Ti6Al4V difficult in some biomedical applications, for example, articulating components of prostheses. To overcome this limitation, nitriding has been investigated as a surface-hardening method for titanium. Although nitriding greatly improves the wear resistance, this method reduces the fatigue strength. Low cycle fatigue performance in air of nitrided Ti6Al4V at different deformation amplitudes has been studied. Results show a reduction of low cycle fatigue life of up to 10% compared to the non-treated material. Studies suggest it is not related to the titanium nitride surface layer, but to microstructural changes caused by the high temperature treatment. (Journal of Applied Biomaterial & Biomechanics 2003; 1: 43-7).

[Optic pathway gliomas in neurofibromatosis type I. Longitudinal study of 30 cases in two multidisciplinary practices]

The aim of this study was to analyse the outcome of optic pathway gliomas in 30 children with neurofibromatosis type 1, the indications of treatment, and the follow-up and screening protocol.

PATIENTS AND METHODS

All patients with a minimal two years follow-up (median six years, range two to 19 years), in two multidisciplinary consultations of Saint-Vincent-de-Paul (Paris) and Purpan (Toulouse) hospitals, were included in the study. In our series, we practiced systematic screening MRI in children under six years' of age or with neuropsychological deficiency that may imply an unreliable ophthalmological examination.

RESULTS

Thirty-seven percent (11 patients) had progressive ophthalmological signs and were treated, and 63% (19 patients) were not progressive. Our study confirmed that most of optic pathway gliomas were stable during evolution, but rare cases may have bad prognosis.

CONCLUSION

Our study supported the importance of close ophthalmological follow-up during childhood for which screening methods are discussed. There is a consensus to limit treatment for patients with progressive ophthalmological symptoms.

[Neurofibromatosis 1: recommendations for management]

Twenty experts, members of a French medical network devoted to neurofibromatosis 1 have elaborated recommendations for the management of the disease. Bibliography was obtained through a Medline of articles from 1966 to 1999 for the terms neurofibromatosis, NF1, neurofibroma and from textbooks. A consensual document was written taking into account extracted data. An annual careful clinical examination is recommended except in cases with complications. Screening investigations are not recommended due to the rarity of complications, generally symptomatic and easily detected during the clinical follow-up. The only controversial exception might be magnetic resonance imaging for early detection of optic pathway gliomas in young children. A co-ordinated follow-up in specialised multidisciplinary centres, providing patients with a rational management, is recommended.

The A17L gene product of vaccinia virus is exposed on the surface of IMV

The p21 membrane protein of vaccinia virus (VV), encoded by the A17L gene, has been reported to localize on the inner of the two membranes of the intracellular mature virus (IMV). It has also been shown that p21 acts as a membrane anchor for the externally located fusion protein p14 (A27L gene). Since p14 is located on the surface of IMVs, it is hard to envision that p21 should be located only on the inner membrane. Our results from (i) immunoelectron microscopy, (ii) biotinylation, and (iii) protease treatment of purified IMVs showed that the N-terminus of p21 is exposed on the surface of virus particles, while the C-terminus is embedded in the membrane. Mono-specific antibodies to the N-terminus of p21 neutralize infection of VV while antibodies to the C-terminal domain do not. We suggest that p21 molecules are located both in the inner and in the outer membrane of IMV.

Infantile Alexander disease: spectrum of GFAP mutations and genotype-phenotype correlation

Heterozygous, de novo mutations in the glial fibrillary acidic protein (GFAP) gene have recently been reported in 12 patients affected by neuropathologically proved Alexander disease. We searched for GFAP mutations in a series of patients who had heterogeneous clinical symptoms but were candidates for Alexander disease on the basis of suggestive neuroimaging abnormalities. Missense, heterozygous, de novo GFAP mutations were found in exons 1 or 4 for 14 of the 15 patients analyzed, including patients without macrocephaly. Nine patients carried arginine mutations (four had R79H; four had R239C; and one had R239H) that have been described elsewhere, whereas the other five had one of four novel mutations, of which two affect arginine (2R88C and 1R88S) and two affect nonarginine residues (1L76F and 1N77Y). All mutations were located in the rod domain of GFAP, and there is a correlation between clinical severity and the affected amino acid. These results confirm that GFAP mutations are a reliable molecular marker for the diagnosis of infantile Alexander disease, and they also form a basis for the recommendation of GFAP analysis for prenatal diagnosis to detect potential cases of germinal mosaicism.

Disaster coordination and management: summary and action plans

INTRODUCTION

Disaster is a collective responsibility requiring coordinated response from all parts of society. This theme focused on coordination and management issues in a diverse range of scenarios.

METHODS

Details of the methods used are provided in the preceding paper. The chairs moderated all presentations and produced a summary that was presented to an assembly of all of the delegates. Although the main points developed in Themes 1 and 4 were different from each other (as reported in the Results section), their implementation was similar. Therefore, the chairs of both groups presided over one workshop that resulted in the generation of a set of Action Plans that then were reported to the collective group of all delegates.

RESULTS

The main points developed during the presentations and discussions included: (1) the need for evidence-based assessments and planning, (2) the need for a shift in focus to health-sector readiness, (3) empowerment of survivors, (4) provision of relief for the caregivers, (5) address the incentives and disincentives to attain readiness, (6) engage in joint preparation, response, and training, (7) focus on prevention and mitigation of the damage from events, and (8) improve media relations. There exists a need for institutionalization of processes for learning from experiences obtained from disasters.

DISCUSSION

Action plans presented include: (1) creation of an Information and Data Clearinghouse on Disaster Management, (2) identification of incentives and disincentives for readiness and develop strategies and interventions, and (3) act on lessons learned from evidence-based research and practical experience.

CONCLUSIONS

There is an urgent need to proactively establish coordination and management procedures in advance of any crisis. A number of important insights for improvement in coordination and management during disasters emerged.

Efficacy and tolerance of adapalene cream 0.1% compared with its cream vehicle for the treatment of acne vulgaris

Adapalene gel 0.1% is approved for use in the treatment of acne vulgaris. A new cream formulation, adapalene cream 0.1%, has been developed. Our objective was to evaluate the efficacy and tolerability of adapalene cream 0.1% in comparison with its cream vehicle, applied once daily for 12 weeks to patients with facial acne vulgaris. We used a 12-week, multicenter, randomized, double-blind, vehicle-controlled, comparative phase 3 study of adapalene cream 0.1% and cream vehicle. The study enrolled 237 patients (125 males and 112 females), aged 12 through 30 years, with mild-to-moderate acne vulgaris. Adapalene cream 0.1% demonstrated superior efficacy compared with its cream vehicle. Significantly lower numbers of total inflammatory and noninflammatory lesion counts were observed at the end of the study period in patients using adapalene cream 0.1% as opposed to those using cream vehicle (P<.05 compared with baseline, for all 3 parameters). Adapalene cream 0.1% caused more cutaneous side effects than the cream vehicle, but these were tolerated in most patients. In summary, the results of this study indicate that adapalene cream 0.1% demonstrates superior efficacy over cream vehicle for the treatment of acne vulgaris. Adapalene cream 0.1% also has excellent tolerability and is associated with a low incidence of cutaneous adverse events.

Proteolytic exposure of a cryptic site within collagen type IV is required for angiogenesis and tumor growth in vivo

Evidence is provided that proteolytic cleavage of collagen type IV results in the exposure of a functionally important cryptic site hidden within its triple helical structure. Exposure of this cryptic site was associated with angiogenic, but not quiescent, blood vessels and was required for angiogenesis in vivo. Exposure of the HUIV26 epitope was associated with a loss of alpha1beta1 integrin binding and the gain of alphavbeta3 binding. A monoclonal antibody (HUIV26) directed to this site disrupts integrin-dependent endothelial cell interactions and potently inhibits angiogenesis and tumor growth. Together, these studies suggest a novel mechanism by which proteolysis contributes to angiogenesis by exposing hidden regulatory elements within matrix-immobilized collagen type IV.

Successful surgical relief of seizures associated with hamartoma of the floor of the fourth ventricle in children: report of two cases

OBJECTIVE AND IMPORTANCE

To discuss the physiopathology and surgical handling of seizures due to hamartoma of the floor of the fourth ventricle in two children.

CLINICAL PRESENTATION

Two girls aged 3 years at the time of their operations presented with seizures due to a lesion of the floor of the fourth ventricle. The seizures began within the first days of life and consisted of hemifacial contraction, then head deviation, blinking of the eyelids, and intermittent dysautonomic manifestations. The interictal neurological condition seemed normal in one patient and showed a slight development delay in the other. An ictal electroencephalogram showed slow waves in the posterior areas. A magnetic resonance imaging scan revealed a mass that remained unchanged on serial examinations bordering the fourth ventricle, with an isointense signal on T1-weighted sequences and high-intensity signals on T2-weighted sequences without gadolinium enhancement. An ictal single-photon emission computed tomographic scan showed hyperperfusion in the lesion in both girls.

INTERVENTION

The operation consisted of resection and disconnection of the lesion. An electrical recording was obtained in one patient during the operation while she was anesthetized; the recording, made by means of a depth electrode with five contacts inside the lesion, indicated that repetitive theta rhythmic discharges were present. Neuropathology was consistent with a hamartoma. In both girls, the seizures disappeared after their operations, and antiepileptic drugs were withdrawn (follow-up periods, 8 and 3 yr, respectively).

CONCLUSION

Considering the results of single-photon emission computed tomography, the intralesional electrical record, and the relief of seizures after the operation, we postulate that the seizures arose from inside the lesion. This particular kind of noncortical seizure is similar to gelastic seizure due to hypothalamic hamartoma.

Pontoneocerebellar hypoplasia: definition of MR features

We report five patients with pontoneocerebellar hypoplasia. Because the issue of cerebellar malformations is a difficult subject, we tried to define criteria for diagnosis on MRI: a thin flat pons with disappearance of the anterior curve, a small cerebellum with predominant flattening of the hemispheres and shortened cerebellar fissures, in contrast to atrophy. The posterior fossa is not enlarged. We emphasize the probable late onset of the disease in fetal life because of the demonstration of the abnormalities at US during the last trimester of the pregnancy in one patient. Prenatal diagnosis is important because of possible autosomal recessive transmission.

Information and competency for consent to pharmacologic clinical trials in Alzheimer disease: an empirical analysis in patients and family caregivers

This study was undertaken to evaluate (1) what information normal and Alzheimer disease (AD) participants are able to manage; (2) the correlation between the degree of competency and age, education and dementia scores, and the ability of dementia scores to predict incompetence; and (3) the capacity to retain consent-related information. To fulfil these aims, a four-point competency rating scale (1 = incompetent, 2 = marginally competent, 3 = sufficiently competent, and 4 = completely competent) was used in 70 patients (Mini-Mental State Examination [MMSE] score >9; Global Deterioration Scale score <6) and in 40 cognitively normal caregivers. Patients were divided into two subgroups (competency ratings 1 and 2 versus 3 and 4) to calculate positive and negative predictive values of MMSE and Alzheimer Disease Assessment Scale-cognitive (ADAScog) for absent/marginal competence. Main results were as follows: (1) 32.9% of AD patients were "incompetent" (no caregivers), 37.1% were "marginally competent" (20% caregivers), 18.6% were "sufficiently competent" (50% caregivers), and 11.4% were "completely competent" (30% caregiverss). (2) Competency ratings and age did not correlate in AD, whereas a negative correlation was significant in caregivers; competency ratings positively correlated to education in caregivers. (3) ADAScog and MMSE were the tests most significantly correlated to competency; MMSE score below 18 had a positive predictive value of 95% and a negative predictive value of 63.3%. The fact that 95% of patients with MMSE scores below 18 are incompetent or marginally competent points to an urgent need for ethical procedures capable of creating a balance between difficulties in obtaining valid consent and a patient's right to benefit from advances in clinical research.

Suppression of asthma-like responses in different mouse strains by oral tolerance

In this study we examined the effect of oral antigen (Ag) administration on the development of experimental asthma in different mouse strains. We selected BALB/c, BP2, CBA/Ca interleukin (IL)-5 transgenic, and BALB/c T-cell receptor-delta-deficient mouse strains because they exhibit different aspects of the asthma syndrome. Mice exposed to 1% ovalbumin (OVA), dissolved in the drinking water for 5 consecutive days, became unresponsive to subsequent immunogenic OVA challenges. This regimen of OVA administration induced Ag-specific unresponsiveness in all mouse strains tested, including gammadelta-deficient mice that are said to be resistant to tolerance induction. The Ag-specific unresponsiveness was characterized by reduced (almost absent) airway eosinophilic inflammation, airway hyperreactivity, and mucus production; also by low levels of T helper (Th) 2-type cytokines in bronchoalveolar lavage fluid, and decreased immunoglobulin (Ig) G1 and IgE OVA-specific antibody production. The unresponsive state was not associated with increased levels of the suppressive cytokines IL-10 and transforming growth factor (TGF)-beta or with immune deviation toward the Th1 pathway due to increased levels of interferon-gamma and IL-12. Moreover, treatment with anti- TGF-beta antibodies did not abrogate oral tolerance. Oral Ag administration was quite effective in suppressing the development of key features of asthma when initiated after primary immunization (Day 0) or after booster (Day 7), but not after challenge (Day 14) when it increased allergic responses. Collectively, our findings show for the first time the beneficial and detrimental effects of oral Ag administration on the development of experimental asthma.

Plastid-expressed 5-enolpyruvylshikimate-3-phosphate synthase genes provide high level glyphosate tolerance in tobacco

Plastid transformation (transplastomic) technology has several potential advantages for biotechnological applications including the use of unmodified prokaryotic genes for engineering, potential high-level gene expression and gene containment due to maternal inheritance in most crop plants. However, the efficacy of a plastid-encoded trait may change depending on plastid number and tissue type. We report a feasibility study in tobacco plastids to achieve high-level herbicide resistance in both vegetative tissues and reproductive organs. We chose to test glyphosate resistance via over-expression in plastids of tolerant forms of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). Immunological, enzymatic and whole-plant assays were used to prove the efficacy of three different prokaryotic (Achromobacter, Agrobacterium and Bacillus) EPSPS genes. Using the Agrobacterium strain CP4 EPSPS as a model we identified translational control sequences that direct a 10,000-fold range of protein accumulation (to >10% total soluble protein in leaves). Plastid-expressed EPSPS could provide very high levels of glyphosate resistance, although levels of resistance in vegetative and reproductive tissues differed depending on EPSPS accumulation levels, and correlated to the plastid abundance in these tissues. Paradoxically, higher levels of plastid-expressed EPSPS protein accumulation were apparently required for efficacy than from a similar nuclear-encoded gene. Nevertheless, the demonstration of high-level glyphosate tolerance in vegetative and reproductive organs using transplastomic technology provides a necessary step for transfer of this technology to other crop species.

Urinary retention following routine neurosurgical spine procedures

BACKGROUND

The rate and duration of urinary retention after routine cervical and lumbar spine procedures were studied.

METHODS

Preoperative, intraoperative, and postoperative factors related to urinary retention (age, sex, duration of operation, medications, Foley use, hospital stay, and cost) were analyzed in a retrospective review of 503 patients' charts.

RESULTS

Urinary retention occurred 38% of the time following cervical and lumbar spine procedures. Advanced age and preoperative beta blockers contributed to a higher incidence of urinary retention. Preoperative anti-inflammatory medications and narcotic analgesics reduced the frequency of urinary retention. The duration of urinary retention was prolonged in older patients and patients who underwent intraoperative Foley catheterization. Urinary retention contributed to longer hospitalization and increased hospital costs.

CONCLUSIONS

Transient urinary retention is a common complication of routine neurosurgical spine procedures that prolongs hospital stays and increases the costs of hospitalization.