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Biomedical subjects

K M Kennedy

Publications and source records attributed to K M Kennedy.

10 recordsLinked to original sources
PubMed1999

Synaptic vesicle recruitment for release explored by Monte Carlo stimulation at the crayfish neuromuscular junction.

Neurotransmission at chemically transmitting synapses requires calcium-mediated fusion of synaptic vesicles with the presynaptic membrane. Utilizing ultrastructural information available for the crustacean excitatory neuromuscular junction, we developed a model that employs the Monte Carlo simulation technique to follow the entry and movement of Ca2+ ions at a presynaptic active zone, where synaptic vesicles are preferentially docked for release. The model includes interaction of Ca2+ with an intracellular buffer, and variable separation between calcium channels and vesicle-associated Ca(2+)-binding targets that react with Ca2+ to trigger vesicle fusion. The end point for vesicle recruitment for release was binding of four Ca2+ ions to the target controlling release. The results of the modeling experiments showed that intracellular structures that interfere with Ca2+ diffusion (in particular synaptic vesicles) influence recruitment or priming of vesicles for release. Vesicular recruitment is strongly influenced by the separation distance between an opened calcium channel and the target controlling release, and by the concentration and binding properties of the intracellular buffers, as in previous models. When a single opened calcium channel is very close to the target, a single synaptic vesicle can be recruited. However, many of the single-channel openings actuated by a nerve impulse are likely to be ineffective for release, although they contribute to the buildup of total intracellular Ca2+. Thus, the overall effectiveness of single calcium channels in causing vesicles to undergo exocytosis is likely quite low.

Animals↗
PubMed1999

Lessons learned from three physician-equity models.

To improve the profitability of group practice ownership, some healthcare organizations have structured arrangements to include a form of physician equity. An equity incentive is designed to encourage physician behavior that supports business operations by tying financial reward to overall organizational performance. Three physician-equity models--third-party integration, joint venture management services organization (MSO), and physician-owned practice management company--have used the physician equity incentive with varying degrees of success. The experiences of three healthcare systems that implemented these models demonstrates that strategies often cannot be executed as planned, growth should not be assumed, and the changing healthcare marketplace is unpredictable.

Connecticut↗
PubMed1998

Alternatives to traditional capitation in managed care agreements.

Risk arrangements typically fall into one of three categories: primary care capitation, professional services capitation, and global, or full-risk, capitation. Yet, in light of various disadvantages associated with these three methods, such as high administrative costs and inappropriate levels of risk assumed by providers, many healthcare payers and providers are experimenting with alternative payment plans. These alternatives include contact capitation arrangements, under which specialists receive a capitation payment on a per referral basis; open-access arrangements, under which patients do not need a gatekeeper referral to see specialists; and capitation arrangements with quality and hospital utilization bonuses, under which specialists and primary care physicians receive a capitation payment plus the potential for bonuses based on quality and utilization criteria.

Capitation Fee↗
PubMed1998

Physician equity in health care delivery systems: three alternative models.

The 1990s have seen many health care organizations attempting to merge, acquire, or affiliate with physician groups. Many have failed to provide physicians a stake in the success of the newly formed enterprise, frequently resulting in declining physician productivity, poor morale, and large operating losses. These problems warrant a reexamination of the traditional acquisition model of growth in favor of structures that retain a physician ownership component. This article examines three models of health care organization in which physicians share in the success of the enterprise and compares them in terms of ownership structure, governance, and funds flow.

Delivery of Health Care, Integrated↗
PubMed1997

Evaluating and negotiating a profitable capitation contract.

Evaluating the financial terms of capitation contracts and negotiating their nonfinancial provisions are becoming increasingly important responsibilities for healthcare financial managers. To evaluate the financial terms of a contract, financial managers must understand both incremental and replacement pricing strategies. They also must understand when strategic positioning objectives make a capitated plan attractive despite limited financial rewards. Before a contract is accepted, financial managers can take steps to increase its potential profitability by negotiating the nonfinancial provisions that can help control contract expenses. These provisions are related to services to be provided, payment terms, withholds and risk pools, access to data, provision of eligibility data, utilization review and quality assurance procedures, filing of grievances, contract renewal terms, and contract termination.

Capitation Fee↗
PubMed1997

Matching physician compensation plans to capitation levels.

As managed care penetration increases, physician compensation plans need to reflect the current transition from fee-for-service to capitated payment. In choosing the compensation structure that will be most beneficial to the success of the group practice and secure physician buy-in, practices need to assess their mission, goals, and corporate culture. They also need to assess their percentage of capitation to total revenues and develop, when necessary, new compensation pools that reward physicians for a variety of behaviors, such as increased productivity and utilization control. Compensation plans should be fair, flexible, and simple to understand and administer.

Capitation Fee↗
PubMed1994

Corticotropin-releasing factor binding protein dimerizes after association with ligand.

We have suggested recently that the fall in plasma CRF-binding protein (BP) during the last few weeks of pregnancy is a direct effect of association with its ligand because of the rapid decrease in plasma BP concentration seen in normal males reaching a nadir some 15 min after a bolus injection of synthetic CRF. In the present study, we have investigated the physicochemical properties of both natural and recombinant BP by gel filtration under physiological conditions and have shown that association of human CRF to this BP results in an increase in molecular weight consistent with the formation of a dimer form of the BP ligand complex. The dimer is more stable when the interaction occurs in the presence of serum or if a peptide with a higher affinity for the BP is substituted as ligand. Experimental evidence would also suggest that the dimer BP has a higher affinity for ligand than the monomeric form. We suggest that this dimerization occurs in vivo when CRF is released into the bloodstream and provides the trigger that causes the uptake of the complex at specific receptor sites.

Animals↗
PubMed1994

A "high-tech," "soft-touch" immunization program for members of a Medicaid managed care organization.

Immunization rates among the very poor are critically low. The solution to improving rates requires technological tracking of immunizations linked to extensive home visiting outreach services as well as physician and member support services to increase compliance with recommended immunization schedules. This paper describes the development and implementation of a comprehensive immunization program which incorporates these strategies for members of a Medicaid managed care organization. Analysis of preliminary data provides some indication of the value of the tracking system and the effectiveness of incentives and home visiting on member compliance with immunizations.

Accounting↗
PubMed1992

Auditory brainstem response to tone bursts in quiet, notch noise, highpass noise, and broadband noise.

This study investigated the effects of tone bursts (1000 Hz, 2000 Hz, and 4000 Hz) in quiet, notch noise, highpass noise, and broadband noise on the identifiability, latency, and amplitude of the auditory brainstem response (wave V). Normal listeners were presented with 40 dB and 80 dB nHL tone bursts having rise-plateau-fall times of 1 msec. Wave V was observed in all subjects at 40 dB and 80 dB nHL for the quiet and noise conditions. The latency findings suggest that responses elicited by the 80 dB nHL tone bursts in quiet were, in part, mediated by regions on the basilar membrane that did not correspond to the center frequency of the tone burst. To increase frequency-specificity, high-level tone bursts (e.g., 80 dB nHL) should be mixed with notch, highpass, or broadband noise. The use of noise conditions for low intensity levels (e.g., 40 dB nHL) does not appear necessary for isolating the response because both the notch and the highpass conditions yielded latencies similar to the quiet condition. Although similar wave V amplitudes were found at all frequencies, amplitudes were smaller for the broadband noise than for the quiet, notch, and highpass conditions. Thus, the latter conditions seem preferred.

Acoustic Stimulation↗