Clinical evaluation of the Novacor totally implantable ventricular assist system. Current status.

The totally implantable Novacor left ventricular assist system (LVAS) is currently approaching clinical evaluation. In vivo testing and production are underway with National Institutes of Health (NIH) support. Activity over the past year has focused on manufacturing engineering, preproduction quality assurance, and in vivo experiment completion. Subsequent to successful completion of the NIH-sponsored, 2-year preclinical device readiness test (DRT), a number of refinements were identified and approved by the NIH technical/data review board. Most of these were necessitated by obsolescence or unavailability of electronic components and the decision to use only high reliability military (MIL) qualified electronic components and processes. A few additional refinements were identified to increase design margins, all of which were qualified by accelerated testing. The development of production processes, automated test programs, and MIL compliant environmental stress screening procedures was completed. Production of LVAS subsystems, including core electronic components (hybrids, application-specific integrated circuits, and surface mount boards), was initiated. Animal studies are underway. The clinical trial, at Presbyterian-University Hospital of Pittsburgh and St. Louis University Medical Center, awaits completion of in vivo experiments, protocol development, and Food and Drug Administration approval.

Thyroparathyroidectomy produces a progressive escape deficit in rats.

Abnormal thyroid status and affective disorders have been associated in the human clinical literature. It has recently been shown that pretreatment with thyroid hormone can prevent escape deficits produced by inescapable shock in an animal analogue of depression. In this report we provide evidence that hypothyroid status can produce an escape deficit in rats. While sham-operated rats improved their performance on a simple escape task over three days of testing, thyroparathyroidectomized rats showed a pronounced decrease in their responses. Markov transition analysis was used to obtain conditional probabilities of escaping given a prior escape or failure to escape for the two groups. This analysis shows that the structure of the data set may be similar for the two groups. These results suggest that if intact rats learn to escape, then hypothyroid rats may learn not to escape.

[Potentialities of radiological diagnosis of injuries to the dorsal pelvic ring]. / Möglichkeiten der radiologischen Diagnostik bei Verletzungen des dorsalen Beckenringes.

Thirty-five patients with fractures of the anterior pelvis, in whom there was clinical suspicion of trauma to the posterior part of the pelvis, were examined by conventional radiology, bone scintigraphy and computed tomography, and the results were compared. CT provided the most information and made it possible to evaluate the soft tissues and organs of the pelvis. Bone scintigraphy produced the same number of abnormal findings as CT (sensitivity 100%), but was unable to differentiate between lesions of the sacro-iliac joints, fractures of the sacrum, combined injuries or degenerative processes. A positive bone scintigram is a reliable finding, with a high predictive value. A negative result excludes a fracture or other lesions of the dorsal portion of the pelvis completely. Conventional radiographs provided a correct diagnosis in only 37.1% as compared with CT.