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To investigate the relationship between human T-lymphotropic virus (HTLV) types I and II and the pathogenesis of autoimmune thyroid diseases, we examined serum anti-thyroid antibodies in 1019 blood donors with or without serum anti-HTLV-I antibody as well as proviral DNA for HTLV-II in leukocyte DNA by the polymerase chain reaction in 395 blood donors with or without anti-thyroid antibodies. The frequency of donors with anti-HTLV-I antibody who also showed anti-thyroid antibodies (7.9%) tended to be higher than that (6.3%) among donors who did not have the anti-HTLV-I antibody. The frequency of anti-thyroid antibodies in 125 young male donors aged 16–39 years with anti-HTLV-I antibody (4.8%) was significantly higher (P

Human T-lymphotropic virus type l (HTLV-I) protein and messenger RNA (mRNA) for HTLV-I were examined in thyroid tissues from two patients with Hashimoto's thyroiditis and serum anti-thyroid antibody. The virus envelope protein and signals for the mRNA were detected in many of the follicular epithelial cells of the thyroid tissue from one of the patients, respectively, by immunohistochemistry and in situ hybridization. PCR-Southern blotting revealed the presence of HTLV-I DNA in the thyroid tissue, in which the viral protein and mRNA were detected, although no virus particles were found in the epithelial cells by electron microscopy. HTLV-I virus was not present in the thyroid tissue from the second patient. The present findings suggest that infection of thyroid tissue with HTLV-I is associated with the pathogenesis of Hashimoto's thyroiditis in some patients.

The intracellular localization of myoglobin mRNA in the skeletal muscles of normal subjects was examined by in situ hybridization using a biotin-labeled cDNA probe. By phase-contrast microscopy, myoglobin mRNA signals were demonstrated to be located preferentially on the A-band. Two different methods of tissue preparation, i.e., pre-embedding method and post-embedding method, were used for the electron microscopic study. With the pre-embedding method, only a few gold particles were found to be associated with cytoskeletal filaments in the intermyofibrillar space. With the post-embedding method, superior preservation of sections and higher signal intensities were obtained. Although most of the gold particles were localized on the A-band, some were seen in other regions; i.e., in the intermyofibrillar space, perinuclear space, or the I-band, where myoglobin is localized. These findings suggest that myoglobin is primarily synthesized on the A-band, where ribosomes predominantly exist, although myoglobin is also localized on the I-band. The predominant localization of myoglobin mRNA on the A-band may aid in the mRNA transcription and may be related to the regulation of myoglobin synthesis in skeletal muscle cells.

The intracellular localization of myoglobin(Mb) mRNA in the skeletal muscles of normal subjects and patients with Duchenne muscular dystrophy(DMD) or amyotrophic lateral sclerosis(ALS) was examined by in situ hybridization using a biotin-labeled cDNA probe. In cross sections of normal muscles, Mb mRNA signals were demonstrated to be diffusely distributed as granular reaction products throughout the sarcoplasm, and in longitudinal sections the products were observed preferentially on the A-band. In DMD or ALS muscles, the distribution of granular mRNA signals showed some similarities with that in normal muscles, although degenerated fibers revealed a heterogenous distribution of the signals. In DMD muscles, the optical density(OD) of stained signal was higher in non-atrophic fibers and lower in atrophic fibers than in normal muscles. In ALS muscles, the OD was lower than in normal muscles. These results suggest that Mb mRNA is distributed preferentially on the A-band of the muscle fibers, and that in diseased muscle fibers Mb synthesis is affected by pathological changes.

Seven patients, aged 10–17 years, with Duchenne muscular dystrophy were treated orally with prednisolone (PSL) at a dose of 0.8–1.0 mg/kg per day for 8 weeks. During the treatment their muscle strength, serum creatine kinase (CK) activity, serum levels of myoglobin (Mb), and urinary excretion of 3-methyl-histidine (3-MeH) and glycine (Gly) were measured serially. In all the patients, the motor function or muscle strength improved, and the serum CK activity and Mb level decreased during PSL treatment. Urinary excretion of 3-MeH, a unique constituent of muscle contractile proteins, decreased to 51–63% of the baseline value in weeks 6–9 after the start of PSL administration, and returned to the baseline level in week 12. The ratios of 3-MeH to creatinine and to Gly also decreased during the treatment. Urinary excretion of Gly, which is ubiquitous in all tissues including muscle, did not decrease during the treatment. These findings suggest that PSL inhibits proteolysis of muscle contractile protein.

The isozyme patterns of leukocyte α-d-mannosidase in two sisters with mannosidosis, their parents and a patient with trisomy 19 were studied. The isozyme pattern of liver mannosidase of a normal subject was also studied. In the patients with mannosidosis the neutral isozyme (isozyme C or fraction C) was present, but the acidic isozymes (isozyme A and B or fraction A and B) were not detectable. In their parents the activity of the acidic isozymes was one-third of the normal activity. These findings suggest that the patients are homozygous and their parents are heterozygous in terms of deficiency of acidic isozymes. In the patients with trisomy 19, the activity of α-d-mannosidase was 4.9 times the upper limit of the normal value, while the levels of other lysozomal enzymes were normal. This increase was mainly due to increases of the A and B isozymes of mannosidase. This finding suggests that the gene encoding acidic isozymes, but not that encoding the neutral isozyme, is located on chromosome 19. The isozyme pattern of α-d-mannosidase differed in different tissues of normal subjects, and the difference in severity of lesions in different organs of the patients with mannosidosis could be explained by differences in the isozyme patterns of the enzyme in these organs.