Effect of Programmed Atrioventricular Delay on the Patterns of Mitral and Pulmonary Vein Flow Profiles and Their Durations in Patients with Dual-Chamber Pacemakers.

Cardiac pacemakers are increasingly used in patients with dilated and hypertrophic cardiomyopathy. In these patients, unusually short atrioventricular (AV) delays are used. Changing the AV delay has been shown to affect the mitral E/A velocity ratio, but its effect on the duration of left ventricular (LV) isovolumic relaxation time, LV filling time, or pulmonary vein flow pattern has not been investigated.

IGF-II receptor number is increased in TE-85 osteosarcoma cells by combined magnetic fields.

Human osteosarcoma-derived osteoblast-like cells, TE-85, were used to assess the effect of a low frequency alternating magnetic field in combination with a controlled static magnetic field (combined magnetic fields, CMF) on insulin-like growth factor receptor regulation. In our culture system, application of a 15.3 Hz CMF induces a calculated maximum electrical potential in the culture media of 10(-5) V/m.

Magnetic field-induced changes in specific gene transcription.

Magnetic fields are physical, environmental agents that have been shown to produce a variety of responses in cellular and animal studies, including general changes in gene transcription. In this study, the nuclear run-off assay has been employed to assess alterations in specific gene transcription in CEM-CM3 T-lymphoblastoid cells exposed for 15-120 min to a 1 gauss sinusoidal magnetic field at 60 Hz. Time-dependent and cell density-dependent changes in the transcription of c-fos, c-jun, c-myc and protein kinase C (beta-form) have been observed and quantitated.

Sleep and performance in young adults and older normals and insomniacs during acute sleep loss and recovery.

Many changes occur in sleep as a function of aging, but it is not known whether these changes result in sleep being less restorative. To examine the sleep restorative process, groups of 12 normal young adults and 12 normal and 12 insomniac male subjects, age 55-71, were totally sleep deprived for 64 hours and then allowed recovery sleep. Response speed, immediate recall, sleepiness, and body temperature were tested at approximately 2300, 0115, 0330, 0530 and 0800 during baseline, sleep loss, and recovery nights.

Sleep restoration as a function of periodic awakening, movement, or electroencephalographic change.

Eleven young adults had their sleep briefly disturbed following each 2 min of accumulated sleep for 2 consecutive nights in 3 different weeks. During 1 week the disturbance was a brief awakening followed by a subjective response. During another week subjects were required to make a quarter-body turn response.