Analysis Tools
behavior/neurological
| N |
• mice exhibit no tremor or paralysis, and no defect in ability to hold onto and let go of wire cage bars
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• when held by the tail and placed on a surface, mice show a defective placing reflex, tending to land on their noses instead of on their forefeet
(J:5353)
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• described as slight waddle
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growth/size/body
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• body weight of adults is reduced up to 30%
(J:5353)
• mice weighed only 75% of NMRI controls
(J:22972)
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respiratory system
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• breathing is difficult
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skeleton
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• progressive erosion of the articulating thoracic vertebral surfaces
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• in some animals, the nucleus pulposus is absent
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• variable degenerative changes are noted within disks of one animal and between different animals
• all animals showed some degree of degenerative changes between the fifth cervical and third thoracic vertebra
• changes include the loss of cells, loss of distinction between the nucleus pulpousus and annulus fibrosus, loss of the ring-like structure of the annulus and a wedge shape to the disks
• degenerated material may protrude from the disk space (herniation), and may impinge on the spinal cord
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reproductive system
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• both sexes are fertile, but breeding performance is somewhat reduced, especially in females
• viability is seriously impaired in only the most extremely deformed mice
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muscle
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• between 6 and 25 days of age, prominent necrosis and regeneration is seen in a number of skeletal muscles
• at 47 days of age, skeletal muscle atrophy is observed, but necrosis and regeneration is rare
• at 136 days of age, all muscle groups show some degree of atrophy and fibrosis is present in gracilis
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• extensor digitorum longus (EDL) muscle weighs less than 50% of controls
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• soleus muscle weighs less than 50% of controls
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• between 6 and 25 days of age
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• noted at 47 days of age; progressive and affects all muscles by 136 days of age
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• at all ages, soleus muscles develop only 30% of the force produced by controls and EDL muscle develop 60% of the force of normal EDL
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nervous system
| N |
• gross ultrastructure of the peripheral nervous system and the central nervous system appears similar to controls
• the motor neuron number in the anterior horn of the spinal cord is similar to controls
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• in soleus and sternomastoid muscle, mutant neuromuscular synapses are abnormally arranged and in numerous small patches rather than in well ordered structures
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• at 31 days of age and later, collateral, pre- and ultraterminal motor nerve sprouting is seen in soleus and erector spinae muscles
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homeostasis/metabolism
| N |
• serum enzyme levels of pyruvate kinase and creatine kinase are similar to controls
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limbs/digits/tail
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• extensor digitorum longus (EDL) muscle weighs less than 50% of controls
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• soleus muscle weighs less than 50% of controls
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