ABSTRACT
Congenital myasthenic syndromes (CMS) are clinically and genetically heterogeneous inherited disorders characterized by impaired neuromuscular transmission. Mutations in the acetylcholinesterase (AChE) collagen-like tail subunit gene (COlQ) cause recessive forms of synaptic CMS with end plate AChE deficiency. We present data on 15 COLQ -mutant CMS carrying 16 different mutations (9 novel ones identified) followed-up for an average period of 10 ears. The mean age at the first examination was 19 ears old (range from 3 to 48). We report relapses during short or long-term periods characterized by worsening of muscle weakness sometimes associated with respiratory crises. All the relapses ended spontaneously or with 3-4 DAP or ephedrine with no residual impairment. The triggering factors identified were esterase inhibitors, effort, puberty or pregnancy highlighting the importance of hormonal factors. There was no genotype-phenotype correlation. At the end of the follow-up, 80% of patients were ambulant and 87% of patients had no respiratory trouble in spite of severe relapses.
Subject(s)
Acetylcholinesterase/genetics , Collagen/genetics , Muscle Proteins/genetics , Mutation/genetics , Myasthenic Syndromes, Congenital/diagnosis , Myasthenic Syndromes, Congenital/genetics , Acetylcholinesterase/deficiency , Acetylcholinesterase/metabolism , Adolescent , Adult , Child , Child, Preschool , Collagen/metabolism , Disease Progression , Female , Follow-Up Studies , Genetic Association Studies , Humans , Male , Middle Aged , Muscle Proteins/metabolism , Phenotype , Recurrence , Treatment Outcome , Young AdultABSTRACT
Effects of pressure-shift freezing and/or pressure-assisted thawing on the quality of sea bass muscle were evaluated and compared with conventional (air-blast) frozen and thawed samples. Microstructural analysis showed a marked decrease of muscle cell damage for pressure-assisted frozen samples. According to differential scanning calorimetry (DSC), protein extractability, and SDS-PAGE results, high-pressure treatment (200 MPa) produced a partial denaturation with aggregation and insolubilization of the myosin, as well as alterations of the sarcoplasmic proteins. Only small differences between high-pressure processes (freezing or/and thawing) were registered. High-pressure-treated systems led to a decrease of water holding capacity but differences between high-pressure and conventional methods disappeared after cooking. Muscle color showed important alterations due to high-pressure treatments (increasing L* and b*).
Subject(s)
Bass/physiology , Fish Proteins/chemistry , Food Handling/methods , Food Preservation/methods , Seafood/standards , Animals , Calorimetry, Differential Scanning , Consumer Behavior , Cryopreservation , Freezing , Pigments, Biological/analysis , Pigments, Biological/chemistry , Pressure , Taste , Time FactorsABSTRACT
High-pressure processing is finding a growing interest in the food industry. Among the advantages of this emerging process is the ability to favorably freeze and thaw food. This study aims at comparing the effect of different freezing and thawing processes on the quality of Atlantic salmon fillets. Atlantic salmon (Salmo salar) samples were frozen by Pressure-Shift Freezing (PSF, 200 MPa, -18 degrees C) and Air-Blast Freezing (ABF, -30 degrees C, 4 m/s). Samples were stored 1 mo at -20 degrees C and then subjected to different thawing treatments: Air-Blast Thawing (ABT, 4 degrees C, 4 m/s), Immersion Thawing (IMT, 20 degrees C), and Pressure-Assisted Thawing (PAT, 200 MPa, 20 degrees C). Changes in texture, color, and drip loss were investigated. The toughness of the PSF samples was higher than that of the ABF sample. The modification of color was more important during high-pressure process than during the conventional process. The PSF process reduced thawing drip compared with ABF. The presence of small ice crystals in the pressure-shift frozen sample is probably the major reason leading to the reduced drip volumes. The freezing process was generally much more influent on quality parameters than the thawing process. These results show the interaction between freezing and thawing processes on selected quality parameters.
