Kinematic analysis of lingual fatigue in myasthenia gravis

This study describes a preliminary examination of the viability and suitability of the physiologic technique electromagnetic articulography (EMA) in investigating lingual fatigue in myasthenia gravis (MG). A 52.9-year-old female diagnosed with MG at the age of 18 years, but who was in remission, participated in the study with a matched control subject. Changes in the duration, speed, and range of tongue-tip and tongue-back movements during repetition of /taka/ over two minutes were investigated. Results revealed that the MG subject did not exhibit significant changes in duration, maximum velocity, maximum acceleration, or the distance travelled by her tongue as measured by EMA over the task. The kinematic results were, in part, expected since the MG subject was in remission. The results, therefore, may not be representative of the majority of individuals with active MG. The examination of the current case did highlight, however, the potential advantages of EMA in providing detailed, objective information regarding lingual kinematics for future investigations of individuals with MG. It also showed that EMA may be sensitive in detecting subclinical kinematic features of fatigue in individuals who are in remission from MG. Finally, EMA led to the identification of possible physiologic factors underlying the CV transform effect, which was evident for the MG subject's syllable productions. In the past, the effect had been assumed to be a purely perceptual-based phenomenon.

Acquired myasthenia gravis associated with a non-invasive thymic carcinoma in a dog

An 8 1/2-year-old neutered male Beagle was diagnosed with acquired myasthenia gravis associated with a non-invasive thymic carcinoma. The thymic mass was surgically excised and the dog was treated with pyridostigmine, prednisolone and azathioprine. Serial acetylcholine receptor antibody titres were increased initially but slowly declined to normal values over a period of 24 weeks. Improved exercise tolerance was seen following therapy, however, oesophageal dysfunction persisted. The dog was euthanased 26 weeks after initial presentation due to a complicating illness. A necropsy showed no regrowth or metastasis of the thymic carcinoma.

Dynamic assessment of articulation during lingual fatigue in myasthenia gravis

The present study aimed to investigate how induced lingual fatigue affected lingual strength, articulatory kinematics, and perceptual speech features in CS, a 51-year-old female with active myasthenia gravis (MG), and three age and gender matched control participants, Lingual fatigue was elicited via a series of endurance tasks using a tongue pressure bulb. Following each endurance task, the participants performed a speech task containing the phonemes /k/, /t/, and /j/ that was recorded with an electromagnetic articulograph, followed by a lingual strength assessment using a tongue pressure bulb. Participants repeated this schedule over five phases and kinematic and strength changes during each phase were compared to baseline measurements. All of CSs significant kinematic changes occurred during the final fatigue phase compared to 27.3% of the control group's kinematic changes occurring during this phase, suggesting the kinematic changes associated with fatigue were not accelerated in CS. The endurance tasks also elicited different kinematic effects for CSs anterior and posterior tongue segments. While CS exhibited mostly similar kinematic and perceptual changes to the control group, some of CS's perceptual transcriptions for /k/ and kinematic changes were not replicated, indicating that some different perceptual and physiological consequences to CS's speech were elicited by the endurance tasks.

Autoimmune Neurological Disease

This book provides a comprehensive and critical overview of the immunological aspects of autoimmune neurological disease. These diseases include common conditions such as multiple sclerosis, the Guillain–Barré syndrome and myasthenia gravis. The introductory chapters on antigen recognition and self–non-self discrimination, and on neuroimmunology, are followed by chapters on specific diseases. These are presented in a standardized format with sections on clinical features, genetics, neuropathology, pathophysiology, immunology and therapy. Each chapter has a concluding section which summarizes key points and suggests directions for future research. Animal models of autoimmune neurological disease are also covered in detail because of their importance in understanding the human diseases. The book is suitable for clinicians and neurologists managing patients with these diseases, and for immunologists, neuroscientists and neurologists investigating the pathogenesis and pathophysiology of these disorders.

Dilution versus dialysis - A quantitative study of the oxidative refolding of recombinant human alpha-fetoprotein

Alpha-fetoprotein (AFP) is a commercially important polypeptide with important diagnostic. physiological and immunomodulatory functions. Previous studies into the refolding of this macromolecule are contradictory. and variously suggest that AFP denaturation may be irreversible or that refolding may be achieved by reducing denaturant concentration through dilution but not dialysis. Importantly, these same previous studies do not provide quantitative metrics by which the Success of refolding, and the potential for bioprocess development. can be assessed. Moreover, these same studies do not optimize and control refolding redox potential - an important factor considering that AFP contains 32 cysteines which form 16 disulfide bonds. In this current study, a quantitative comparison of recombinant human AFP (rhAFP) refolding by dilution and dialysis is conducted under optimized redox conditions. rhAFP refolding yields were > 35% (dialysis refolding) and > 75% (dilution refolding) as assessed by RP-HPLC and ELISA, with structural Similarity to the native state confirmed by UV spectroscopy. Dialysis refolding yield was believed to be lower because the gradual reduction in denaturant concentration allowed extended conformational searching. enabling more time for undesirable interaction with other protein molecules and/or the dialysis membrane, leading to a Sub-optimal process outcome. Significant yield sensitivity to redox environment was also observed, emphasizing the importance of physicochemical optimization. This study demonstrates that very high refolding yields can be obtained, for a physiologically relevant protein, with optimized dilution refolding. The study also highlights the quantitative metrics and macromolecular physical spectroscopic 'fingerprints' required to facilitate transition from laboratory to process scale.