In the myosin-linked regulatory mechanism typified by the molluscan scallop adductor muscle, contraction is controlled by Ca2+ binding to sites on the thick filament protein, myosin. The regulatory light chains of myosin heads are involved directly in this mechanism and early studies suggested that, in the absence of Ca2+, these subunits prevent the interaction of a myosin-adenosine nucleotide complex with the actin-containing thin filament. Subsequently, Ashiba et al. reported that the steady-state ATPase of molluscan myosin exhibits a limited degree of Ca2+ activation in the absence of actin. Recently, however, we have shown that steady-state ATPase activity in relaxing conditions is dominated by the unregulated molecules in the myosin preparation. Single-turnover kinetic methods are required to monitor the highly suppressed ATPase activity of the regulated population. Using the latter approach, we report here that scallop myosin ATPase is reduced about 100-fold on removal of Ca2+. The regulatory light chains maintain the relaxed state via conformational changes which suppress the product release steps, irrespective of the presence of actin.

Actins↗

PubMedDate not supplied

Psychosis and pseudo dementia associated with hemodialysis.

A patient treated with hemodialysis developed psychotic episodes, including visual hallucinations and delusions, as well as symptoms similar to the fatal dialysis dementia. His hospital course seems to demonstrate an original organic dysfunction with behavioral sequelae that were perpetuated by psychological difficulties. His tendency to overdramatize his disability and to adopt an excessively helpless and passive role made treatment difficult. A one-year followup is provided along with a discussion of the relationship of his case to dialysis dementia.

Delusions↗

PubMedDate not supplied

Ultrastructural localization of antigens recognized by the monoclonal antibodies MB1, MB2, MT1, UCHL1, and TAL 1B5.

In this study the ultrastructural localization of antigens recognized by novel antibodies that allow the recognition of lymphoid antigens in conventionally fixed and wax-embedded sections was investigated. MT1, MB1, and UCHL1 recognize antibodies restricted to the cell membrane, whereas the antigen recognized by MB2 is present only in the cytoplasm. These distributions are different from that of immunoreactivity with TAL 1B5 (anti-HLA DR), which is present both on the cell membrane and in the cytoplasm. The significance of these findings is discussed.

Antibodies, Monoclonal↗

PubMedDate not supplied

Rehabilitation counseling of the heart patient in an outpatient rehabilitation center.

Explore the source record for details and available documents.

California↗