RyR1 Deficiency in Congenital Myopathies Disrupts Excitation–Contraction Coupling

In skeletal muscle, excitation–contraction (EC) coupling is the process whereby the voltage‐gated dihydropyridine receptor (DHPR) located on the transverse tubules activates calcium release from the sarcoplasmic reticulum by activating ryanodine receptor (RyR1) Ca²⁺ channels located on the terminal cisternae. This subcellular membrane specialization is necessary for proper intracellular signaling and any alterations in its architecture may lead to neuromuscular disorders. In this study, we present evidence that patients with recessive RYR1‐related congenital myopathies due to primary RyR1 deficiency also exhibit downregulation of the alfa 1 subunit of the DHPR and show disruption of the spatial organization of the EC coupling machinery. We created a cellular RyR1 knockdown model using immortalized human myoblasts transfected with RyR1 siRNA and confirm that knocking down RyR1 concomitantly downregulates not only the DHPR but also the expression of other proteins involved in EC coupling. Unexpectedly, this was paralleled by the upregulation of inositol‐1,4,5‐triphosphate receptors; functionally however, upregulation of the latter Ca²⁺ channels did not compensate for the lack of RyR1‐mediated Ca²⁺ release. These results indicate that in some patients, RyR1 deficiency concomitantly alters the expression pattern of several proteins involved in calcium homeostasis and that this may influence the manifestation of these diseases.     

Plantar pressures and relative lesser metatarsal lengths in older people with and without forefoot pain

Forefoot pain is a common problem in older people. We determined whether plantar pressures during gait and the relative lengths of the lesser metatarsals differ between older people with and without plantar forefoot pain. Dynamic plantar pressure assessment during walking was undertaken using the Tekscan MatScan® system in 118 community‐dwelling older people (44 males and 74 females), mean age 74 (standard deviation = 5.9) years, 43 (36%) of whom reported current or previous plantar forefoot pain. The relative lengths of metatarsals 1–5 were determined from weightbearing X‐rays. Participants with current or previous plantar forefoot pain exhibited significantly (p = 0.032) greater peak plantar pressure under metatarsal heads 3–5 (1.93 ± 0.41 kg/cm² vs. 1.74 ± 0.48 kg/cm²). However, no differences were found in relative metatarsal lengths between the groups. These findings indicate that older people with forefoot pain generate higher peak plantar pressures under the lateral metatarsal heads when walking, but do not exhibit relatively longer lesser metatarsals. Other factors may be responsible for the observed pressure increase, such as reduced range of motion of the metatarsophalangeal joints and increased stiffness of plantar soft tissues. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 427–433, 2013     

Liver transplantation for acute liver failure: are there thresholds not to be crossed?

Factors predicting survival after liver transplantation (LT) for irreversible acute liver failure (ALF) are rare. The aim of this study was to identify prognostic preoperative factors of patients with ALF that predict mortality after LT to avoid futile transplantation. From chart review, we identified 57 patients receiving transplants for ALF from 12/2000 to 09/2010. Recipient and donor data were analyzed and correlated with in‐hospital mortality and patient survival by univariable/multivariable logistic regression and Cox proportional hazards. The survival rates at 30 days and 12 months were 77.2% and 64.9%, respectively. The in‐hospital mortality rate was 29.8%. Follow‐up of patients discharged from the hospital alive showed 30‐day and 12‐month survivals of 100% and 92.5%, respectively. Multivariable analysis of factors known preoperatively showed that the lowest pH of the recipient before LT (P = 0.03) was independently associated with in‐hospital mortality, and the recipient's BMI (P = 0.03) and the lowest pH before LT (P = 0.03) were independently associated with patient survival. A pH of 7.26 was the calculated cutoff (ROC) for increased in‐hospital mortality. Donor factors did not affect patient survival. Patients with ALF and a pH ≤ 7.26 have the worst outcome after liver transplantation. Therefore, emergency liver transplantation should be critically discussed for each individual.     

In-Vitro Analysis of FeMn-Si Smart Biodegradable Alloy

Special materials are required in many applications to fulfill specific medical or industrial necessities. Biodegradable metallic materials present many attractive properties, especially mechanical ones correlated with good biocompatibility with vivant bodies. A biodegradable iron-based material was realized through electric arc-melting and induction furnace homogenization. The new chemical composition obtained presented a special property named SME (shape memory effect) based on the martensite transformation. Preliminary results about this special biodegradable material with a new chemical composition were realized for the chemical composition and structural and thermal characterization. Corrosion resistance was evaluated in Ringer’s solution through immersion tests for 1, 3, and 7 days, the solution pH was measured in time for 3 days with values for each minute, and electro-corrosion was measured using a potentiostat and a three electrode cell. The mass loss of the samples during immersion and electro-corrosion was evaluated and the surface condition was studied by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). SME was highlighted with differential scanning calorimetry (DSC). The results confirm the possibility of a memory effect of the materials in the wrought case and a generalized corrosion (Tafel and cyclic potentiometry and EIS) with the formation of iron oxides and a corrosion rate favorable for applications that require a longer implantation period.     

A familial case of drusen of the optic disk

The present abstract is about a case of drusen of the optic disc (DOD), consisting of three members, belonging to two generations: the mother (41 years) and two daughters (16 and 19 years). Their personal records showed nothing special, except case III-2 with crisis equivalent to the epileptic ones. No changes of the visual acuity and of the visual field were found. Ophthalmoscopy and angiofluorography showed: a bilateral and superficial location of the DOD; no vascular anomalies (discal and peridiscal) or other retinal changes; a trend towards flattening and getting more mat of the DOD, in older cases. It is debated upon the possibility that a single gene might be involved, responsible for an autosomal dominant or autosomal recessive transmission mode.     

The alpha2-macroglobulin gene in AD: a population-based study and meta-analysis

BACKGROUND: Whereas several authors recently reported a positive association between the alpha2-macroglobulin gene (A2M) and late-onset AD (LOAD), others were unable to replicate these findings. Early-onset AD (EOAD) is defined as onset age <65 years. Virtually all patients with LOAD are >65 years of age. OBJECTIVE: To evaluate the role of A2M in AD, the authors conducted a population-based study of EOAD and LOAD as well as a meta-analysis of all studies conducted to date. METHODS: Patients with EOAD (n = 100) were derived from a population-based study in four northern provinces of the Netherlands and the area of metropolitan Rotterdam. Patients with LOAD (n = 344) were drawn from the Rotterdam Study, a population-based prospective study on residents aged 55 years and over of a Rotterdam suburb in the Netherlands. Two polymorphisms were studied, A2M-I/D and A2M-Ile1000Val, in relation to the APOE epsilon4 allele (APOE*4). RESULTS: No genotypic or allelic association was found for either polymorphism in the population-based series of patients with LOAD. In patients with EOAD without APOE*4, a significant increase of carriers of A2M-1000Val was found. The meta-analysis of available published case-control data on these polymorphisms in white and mixed ethnic populations yielded no significant differences between cases and controls. Pooling the Asian studies conducted to date showed a significant decrease in the frequency of A2M-D among patients. CONCLUSIONS: These results suggest that A2M is not genetically associated with LOAD in white patients or mixed populations as found in the United States. In these populations A2M does not have clinical relevance. From a scientific perspective, the findings on EOAD and Asian patients require replication and further research in the A2M region.