Howard W Chang

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Many globular and natively disordered proteins can convert into amyloid fibrils. These fibrils are associated with numerous pathologies as well as with normal cellular functions, and frequently form during protein denaturation. Inhibitors of pathological amyloid fibril formation could be useful in the development of therapeutics, provided that the(More)
Interaction of Ca and acetylcholine (AcCh) ions with purified acetylcholine receptor (AcChR) from Torpedo californica and Electrophorus electricus has been investigated in view of these ions' role proposed in bioelectricity. Spectrophotometric Ca titration using murexide as an indicator and an ultrafiltration method with 45Ca show that AcChR proteins have a(More)
We studied dystrophin in three young girls with a sporadic myopathy of early onset, manifested by mild to severe limb weakness, calf hypertrophy, high serum creatine kinase, normal karyotype, and morphologic features in muscle consistent with muscular dystrophy. DNA analysis did not reveal a deletion of the dystrophin gene. Immunohistochemical studies of(More)
We have found that dystrophin is highly concentrated at neuromuscular junctions and innervated membranes of the electric organ of Torpedo californica. In acetylcholine receptor-rich Torpedo membrane preparations dystrophin represents approximately 0.4% of total protein and can be extracted from these membranes by alkaline treatment in the absence of(More)
Acetylcholine receptors (AChR), purified from electric eel and Torpedo by affinity chromatography using a synthetic quaternary ammonium ligand, bound 10 nmole alpha-bungarotoxin (alpha-BuTx) per mg of protein and demonstrated a common subunit. Rabbits, immunized with either eel or Torpedo/AChR, developed flaccid paralysis barely altered by(More)
Autoimmune diseases, including myasthenia gravis, occur in patients treated with D-penicillamine. Because D-penicillamine might induce autoantibodies by the mechanism of antigenic alteration, we studied the reaction of D-penicillamine with purified acetylcholine receptor from Torpedo californica. We found that brief exposure to D-penicillamine resulted in(More)
We studied monozygous twin women, age 63. One, asymptomatic, had a serum creatine kinase (CK) level of 191 units (normal, 1 to 50); her son died of typical Duchenne muscular dystrophy (DMD) at age 18. Her twin sister had symptomatic limb weakness from about age 40. Her serum CK was 495 units. EMG and muscle biopsy were compatible with myopathy. In the(More)
Because of the association of D-penicillamine (DP) therapy with myasthenia gravis, we have studied long-term DP treatment in five inbred strains of mice with doses comparable to those used in patients with rheumatoid arthritis. No clinical weakness or anti-acetylcholine receptor (AChR) antibody developed with up to 6 months of treatment, but augmented(More)