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Biomedical subjects

F Rothenberg

Publications and source records attributed to F Rothenberg.

10 recordsLinked to original sources
PubMed2004

Electrophysiology and anatomy of embryonic rabbit hearts before and after septation.

Mechanisms of cardiac pacemaking and conduction system (CPCS) development are difficult to study, in part because of the absence of models that are physiologically similar to humans in which we can label the entire CPCS. Investigations of the adult rabbit heart have provided insight into normal and abnormal cardiac conduction. The adult and the embryonic rabbit have an endogenous marker of the entire cardiac conduction system, neurofilament 160 (NF-160). Previous work suggested that ventricular septation correlates with critical phases in avian CPCS development, in contrast to the mouse CPCS. Combining high-resolution optical mapping with immunohistochemical analysis of the embryonic rabbit heart, we investigated the significance of ventricular septation in patterning the rabbit embryonic conduction system. We hypothesized that 1) completion of ventricular septation does not correlate with changes in the ventricular activation sequence in rabbit embryos and 2) CPCS anatomy determines the activation sequence of the embryonic heart. We found that preseptated (days 11-13, n = 13) and postseptated (day 15, n = 5) hearts had similar "apex-to-base" ventricular excitation. PR intervals were not significantly different in either group. CPCS anatomy revealed continuity of the NF-160-positive tract connecting the presumptive sinoatrial node, atrioventricular (AV) junction, and ventricular conduction system. The presence of collagen in the AV junction coincided with the appearance of an AV interval. We conclude that the apex-to-base ventricular activation sequence in the rabbit embryo is present before completion of ventricular septation. CPCS anatomy reflects global cardiac activation as demonstrated by high-resolution optical mapping.

Animals↗
PubMed1994

Specialty services: capitation trends among physician groups.

Many health care providers, particularly those outside of California, Minnesota, and a handful of other states where managed care has become a dominant force, are hesitant to work under capitated contracts. Fear of capitation is basically fear of the unknown. If providers have the tools to track utilization patterns, gather information, and interpret it, then this fear is unjustified.

Ambulatory Care Information Systems↗
PubMed1993

The effect of long-term high-dose naloxone infusion in experimental blunt spinal cord injury.

The effect of long-term continuous subcutaneous infusion of naloxone on blunt spinal cord injury in the rat was assessed using four tests of neurological function, seven histological categories, and two electrophysiological measures. All four neurological function tests showed a trend toward improvement in naloxone-treated animals: the degree of improvement was statistically significant in two of the four categories. A significant reduction in myelin sheath edema was found in the naloxone-treated animals. Although there was a decrease in corticomotor-evoked potentials complexity following injury, there was no significant difference in naloxone-treated animals. Somatosensory-evoked potentials were significantly increased in amplitude and latency in naloxone-treated animals. This increase was most apparent at 60 min: no difference was found by 3 weeks postinjury. These results confirm earlier reports that naloxone can ameliorate the functional neurological deficits of spinal cord injury. Naloxone also produces alterations in the somatosensory-evoked responses in the early phase of treatment and significantly reduces myelin sheath edema.

Animals↗
PubMed1991

The influence of long-term nifedipine or indomethacin therapy on neurologic recovery from experimental spinal cord injury.

Inhibition of prostaglandin pathways and calcium channel conduction has been shown to improve neurological outcome after spinal cord injury. Functional recovery from such intervention has been routinely evaluated by a simple motor examination or somatosensory evoked potentials (SSEPs) after short-term drug administration. We comprehensively evaluated the influence of continuously administered indomethacin and nifedipine on functional outcome after impact spinal cord injury. SSEP and cortico-motor evoked potential records and neurologic examinations were obtained over 6 weeks after injury. Terminal histopathologic changes within the spinal cord were also examined. Only indomethacin significantly improved neurological function and reduced the severity of histopathologic change. Evoked potential analysis was not found to be of prognostic value. Modulation of prostaglandin pathways may enhance neurological recovery after spinal cord injury.

Animals↗
PubMed1983

PPOs: critical elements in their design. Part 4.

There is no certainty that PPOs will be a major factor in the marketplace. It is essential, however, that every provider closely examine the benefits and risks of participation. There is no need to rush head-long into every opportunity offered. Careful consideration of the structure and design of each PPO is important. The basic design elements described here should be addressed whether the reader is creating a PPO or simply being asked to be a participant. If each criterion is either not addressed or is inadequately defined, the person responsible should insist that the situation be corrected. Without such attention, the likelihood of the organization's long-term success is highly questionable.

Community Participation↗