The I segment length has been measured and the number of thin filament periods per I segment has been counted in electron micrographs of Fthesus monkey and human leg muscle fibers. The number of I segment periods in the monkey fiber (60) and in the human fiber (66) multiplied by axial periodicity (385 A ) in thin filaments of living fibers (Huxley and Brown, '67) plus 1,000 .A allowed for Z line width in living fibers, provided a formula for calculation of I segment lengths in living fibers. The calculated I segment lengths are 2.41 P for the monkey and 2.64 , u for the human fiber. The ratio of calculated I segment length over an assumed constant thick filament length (1.6 p ) among vertebrates is in close agreement with the ratio of measured I segment length over measured thick filament I!ength in micrographs of frog, rat, monkey and human leg muscle fibers. The calculated I segment length in the frog (1.95 ru) is compared with that of the human (2.64 P ) to show the relation of I segment length to the length-developed tension diagram and to the series elastic components of the skeletal muscle fiber.Extensive electron microscope studies on thin filament length in frog muscle fibers have been made by two groups of investigators. Carlsen et al. ('61) fixed unstimulated fibers in OsOc and reported the thin filament segments (I segments), which included the Z line and the thin filaments on both sides of the Z line, to be about 1.76 p in length. Page and Huxley ('63), using the same procedures, reported I segment length to be about 1.80 p. On the other hand, if they stimulated frog fibers tetanically and held them at a fixed length during fixation and dehydration the I segments measured 2.00 to 2.05 p . It was concluded that OsOI fixation shortens thin filaments in unstimulated fibers and that formation of cross linkages between thick and thin filaments during tetanic stimulation inhibits Os04-induced shortening. They also reported that the I segment of frog fibers contains 48 periods with a mean value for corrected axial periodicity of 406 A. But, it was necessary for them to multiply the number of periods (48) by 410 A and add 800 A for the measured width of the Z line to attain the 2.05 p AN&*, REC., 178: 63-82.I segment length. Nevertheless, they concluded that the I segment length in the living frog is about 2.05 p and that the periodicity in the thin filaments is about 406 A. The 410 A periodicity used by Page and Hudey in '63 for calculation of I segment length in frog muscle fibers was based upon the x-ray diffraction studies of glycerol-extracted rabbit psoas muscle fibers (Worthington, '59).Confluent evidence from more recent studies of x-ray diffraction patterns, optical diffraction patterns and thin filament structure now indicate that the axial periodicity of thin filaments is somewhat less than 410 A. Huxley and Brown ('67) found in living unstimulated frog sartorius muscle a meridional reflection in the x-ray diffraction pattern that varied from 380 to 390 A wj th an average of 385 A. They s...
Treatment-resistant depression (TRD) is prevalent and associated with a substantial psychosocial burden and mortality. There are few prior studies of interventions for TRD in adolescents. This was the largest study to date examining the feasibility, safety, and efficacy of 10-Hz transcranial magnetic stimulation (TMS) for adolescents with TRD. Adolescents with TRD (aged 12-21 years) were enrolled in a randomized, sham-controlled trial of TMS across 13 sites. Treatment resistance was defined as an antidepressant treatment record level of 1 to 4 in a current episode of depression. Intention-to-treat patients (n = 103) included those randomly assigned to active NeuroStar TMS monotherapy (n = 48) or sham TMS (n = 55) for 30 daily treatments over 6 weeks. The primary outcome measure was change in the Hamilton Depression Rating Scale (HAM-D-24) score. After 6 weeks of blinded treatment, improvement in the least-squares mean (SE) HAM-D-24 scores were similar between the active (−11.1 [2.03]) and sham groups (−10.6 [2.00]; P = 0.8; difference [95% CI], − 0.5 [−4.2 to 3.3]). Response rates were 41.7% in the active group and 36.4% in the sham group (P = 0.6). Remission rates were 29.2% in the active group and 29.0% in the sham group (P = 0.95). There were no new tolerability or safety signals in adolescents. Although TMS treatment produced a clinically meaningful change in depressive symptom severity, this did not differ from sham treatment. Future studies should focus on strategies to reduce the placebo response and examine the optimal dosing of TMS for adolescents with TRD.
Tissue histologically indistinguishable from endometrium was removed from the bladder of a 73-year-old man. The lesional tissue involved the right ureterovesical junction, producing hydronephrosis on the right side. The patient had an adenocarcinoma of the prostate and had been on estrogen therapy for 5 years before diagnosis of endometriosis. Two previous reports of endometriosis in male subjects, who were also on estrogen therapy, are reviewed briefly.
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