TDP-43, a nuclear factor that functions in regulating transcription and alternative splicing, was recently identified as a component of the ubiquitin-positive, tau-negative inclusions specific for frontotemporal lobar degeneration (FTLD-U) and amyotrophic lateral sclerosis (ALS). In the present study, we carried out immunohistochemical and biochemical analyses of brains of Guamanians with the parkinsonism-dementia complex (G-PDC) using anti-TDP-43, anti-tau and anti-ubiquitin antibodies. Immunohistochemistry with anti-TDP-43 antibodies revealed various types of positive structures in the frontotemporal and hippocampal regions of G-PDC cases. Most of these structures were negative for tau. By immunoblot analysis with the TDP-43 antibody, an abnormal 45 kDa band, as well as a diffuse staining throughout the gel, was detected in the sarkosyl-insoluble fractions of G-PDC brains. Dephosphorylation has shown that abnormal phosphorylation takes place in the accumulated TDP-43 seen in FTLD-U and ALS. These results suggest that accumulation of TDP-43 is a common process in certain neurodegenerative disorders, including FTLD-U, ALS and G-PDC.

The magnetic anisotropy and rotational hysteresis loss in Ni-Fe/Mn-Ir bilayers were investigated for films prepared by an ultraclean sputtering deposition process. An in-plane field of 30 Oe during deposition served to define the antiferromagnetic ͑AF͒ alignment axis for the Mn-Ir layer. The Ni-Fe layer thickness was maintained at 50 Å and the Mn-Ir layer thickness ranged from 20 to 200 Å. Room temperature magnetization and torque measurements were made as a function of the Mn-Ir layer thickness d AF and the applied field. The magnetization data were obtained for fields applied in the same direction as during deposition. The magnetization data indicate a critical d AF value of 37 Å, taken as d AF cr . For d AF Ͼd AF cr , the data show hysteresis loops which are displaced along the field axis. The torque response and rotational hysteresis characteristics are sensitive to both d AF and the measuring field. ͑1͒ When d AF is much less than d AF cr , the torque curves have a sin characteristic at fields below 30-40 Oe or so which suddenly changes to a sin 2 characteristic at higher fields. With the onset of the sin 2 torque response, rotational hysteresis loss also appears but then vanishes for fields above 100 Oe or so. ͑2͒ As d AF approaches d AF cr from below, the torque response is the same as above. Here, however, the rotational hysteresis appears for fields well below the field at which the torque response assumes a sin 2 character and persists to the maximum available measuring field of 15 kOe or so. ͑3͒ When d AF exceeds d AF cr , the torque has a predominant sin character at all fields and a small sin 2 component and rotational hysteresis which only around a field of 400 Oe or so. These results, while somewhat complicated, are in accord with responses evaluated from the simple exchange anisotropy model of W. H. Meiklejohn and C. P. Bean ͓Phys. Rev. 102, 1413 ͑1956͒; 105, 904 ͑1957͔͒. Among other things, one may conclude that a rotational hysteresis which persists to high field is not intrinsic to exchange anisotropy.

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