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Biomedical subjects

J A Rice

Publications and source records attributed to J A Rice.

At least 37 records · Page 2Linked to original sources
PubMed1993

Community health assessment. The first step in community health planning.

Hospitals face a paradigm shift: from planning service delivery to population-based community health planning. Comprehensive community health planning is a two-step process: assessment and action, in that order. Assessment identifies community problems and resources; action follows planning, which determines which of those problems should be addressed with which resources. This paper provides an overview of the community assessment process. The first challenge in launching a community health initiative is to identify and recruit partners drawn from the ranks of prominent community organizations, such as school boards, public health agencies, and elected officials. The best enlistment strategies are those that empower persons outside the hospital to take visible control. Defining the community is the first step in analyzing the community. It is important that everyone involved in the assessment process agree on the definition, which should take in those characteristics that make the community unique, including its social systems, environmental factors, and demographics. The next step in the process is developing a community health profile, a set of key community indicators or measures that will help you set priorities, document successes and failures, and monitor trends. There are a number of models available to consult in developing indicators, whether traditional, medically oriented determinants of health or broader parameters, such as housing and public safety. Criteria for selecting indicators include validity, stability and reliability, and responsiveness. Most indicators will be developed using secondary, or already existing, sources of data, such as census data, Medicare and Medicaid files, police records, and hospital admission and exit records. Conducting the community assessment involves putting together a list of problems to be solved and a list of available resources, both of which can be compiled using the same four-step process of gathering and analyzing data: obtaining community input, identifying problems already being addressed, consulting with professional experts, and analyzing existing data. Demographics are one way of analyzing data; another is using a "community scoreboard" that groups causal factors into four categories: lifestyle, environment, human biology, and health services. Once the community assessment is complete, planning and implementation of programs can begin. At the same time, it is essential to mobilize the community to support your initiative. Again, you must look beyond the hospital walls to build a constituency for change, to community leaders in education, employment, transportation and recreation, housing, and the physical environment, as well as health education and preventive services.(ABSTRACT TRUNCATED AT 400 WORDS)

Catchment Area, Health↗
PubMed1992

Maximum likelihood estimation and identification directly from single-channel recordings.

We present a method for analysis of noisy sampled data from a single-channel patch clamp which bypasses restoration of an idealized quantal signal. We show that, even in the absence of a specific model, the conductance levels and mean dwell times within those levels can be estimated. Estimation of the rate constants of a hypothesized kinetic scheme is more difficult. We present examples in which the rate constants can be effectively estimated and examples in which they cannot.

Animals↗
PubMed1992

Bayesian restoration of single-channel patch clamp recordings.

The technique of patch clamp recording makes possible the measurement of current flowing through a single ion channel in a cell membrane. Examination of such recordings suggests that the current is quantal in nature, alternating in a seemingly random manner between "on" and "off," but the recordings are corrupted by noise from a variety of sources. In this paper we propose and illustrate methods for restoring the underlying quantal signal from such noisy measurements. The methods use a Markov chain prior distribution for the underlying quantal process and base the restoration on the resulting posterior distribution.

Algorithms↗
PubMed1991

On the superposition of currents from ion channels.

We derive a number of statistical properties of the superposition of several independent channels contributing to a patch-clamp recording. Failure of these properties indicates dependence of the channels and may suggest the nature of interactions. We show how properties such as dwell-time distributions of the individual channels may be determined from those of the superposition in the case that the channels are independent.

Animals↗
PubMed1991

Water analysis.

Explore the source record for details and available documents.

Water Pollutants↗
PubMed1990

Determination of the extent of DNA bending by an adenine-thymine tract.

We determined the magnitude of the bend induced in DNA by an adenine-thymine tract by measuring the rate of cyclization of DNA oligonucleotides containing phased A tracts. A series of linear multimers with 2-bp single-stranded ends, in which the (A.T)6 tracts are separated by CG2-3C sequences and are positioned 10 and 11 bp apart alternately, were prepared from 21 bp long synthetic duplexed deoxyoligonucleotides. The cyclization rates of the multimers (105-210 bp) and the bimolecular association rate of the 84 bp long multimer were measured in the presence of DNA ligase. From the rate constants of the cyclization and bimolecular association reactions, ring closure probabilities were obtained for the multimers. The systematically bent molecules were simulated by Monte Carlo methods, and the ring closure probabilities were calculated for a given set of junction bend angles. By comparing the calculated values of ring closure probabilities to experimental values and adjusting the junction bend angles to fit experimental values, the extent of bending at the junctions (or the extent of bending for an adenine tract) was determined. We conclude that an A6 tract bends the DNA helix by 17-21 degrees.

Adenine↗
PubMed1989

DNA bending by the bulge defect.

Comparative gel electrophoresis measurements were used to characterize DNA bending in molecules containing an extra adenosine on one strand, the so-called bulge defect. We used oligomers containing A6 tracts separated from the bulged base by varying numbers of nucleotides to determine the direction and magnitude of the bulge bend. Helix unwinding by the bulge was determined from the electrophoretic anomaly as a function of the size of the repeated monomers. We conclude that the bulge bend is 21 degrees +/- 3 degrees, primarily in the direction of tilt away from the bulged base. The total helical advance of the DNA at the bulge site is smaller than would be the case if the complementary T were present, corresponding to an unwinding by 25 degrees +/- 6 degrees. These values are in good agreement with the results of NMR and energy minimization studies of the bulged base in double-helical deoxyoligonucleotides [Woodson, S. A., & Crothers, D.M. (1988) Biochemistry 27, 3130-3141]

Adenine↗
PubMed1989

A note on single-channel autocorrelation functions.

It is shown for time-reversible ion channel gating mechanisms that the sojourn time autocorrelation functions are necessarily nonnegative, decreasing, and convex. It is also shown, again for time-reversible mechanisms, that the lagged moments of all orders are determined by the first three moments. The application of these results to the statistical analysis of single-channel kinetics is briefly discussed.

Ion Channel Gating↗
PubMed1988

The major adduct of the antitumor drug cis-diamminedichloroplatinum(II) with DNA bends the duplex by approximately equal to 40 degrees toward the major groove.

We used gel electrophoresis methods to show that reaction of DNA with cis-diamminedichloroplatinum(II) results in a substantial (approximately equal to 40 degrees) bend in the double helix at the intrastrand crosslink between the N7 atoms of adjacent guanosine nucleosides, which bond to the platinum(II) complex with loss of two chloride ions. Multimers of a 22-base-pair (bp) oligonucleotide platinated at a single site show strong anomalies in their electrophoretic mobilities as a consequence of coherent addition of in-phase platinum-induced bends. Increase of the sequence repeat of the platinated site to 27 bp yields multimers of nearly normal mobility because the bends are out of phase. The direction of Pt-induced bends relative to adenosine-tract bends was determined from the electrophoretic mobility of multimers in which repeated platination sites are interdigitated at various phasings relative to repeated adenosine tracts. Optimum bending occurs when 1.5 helical turns separate the cis-[Pt(NH3)2[d(pGpG)]](N7,N7) adducts from the center of the adenosine tracts. This phasing produces coherent addition of adenosine tract bends toward the minor groove at their centers and Pt-induced bends toward the major groove, where the platinum is located.

Base Composition↗
PubMed1988

Market-driven physical assets management (PAM).

There are close and interactive linkages among market forces, strategic planning, and the physical assets of an institution. In this paper the examination of those linkages leads the author to propose a new organizational arrangement for physical assets management. The idea of construction as an episode in health care facility development is expanded to encompass a life cycle continuum of planning, creating, and maintaining facilities and equipment within a competitive environment.

Forecasting↗
PubMed1985

Kinetic analysis of channel gating. Application to the cholinergic receptor channel and the chloride channel from Torpedo californica.

Identification of the minimum number of ways in which open and closed states communicate is a crucial step in defining the gating kinetics of multistate channels. We used certain correlation functions to extract information about the pathways connecting the open and closed states of the cation channel of the purified nicotinic acetylcholine receptor and of the chloride channel of Torpedo californica electroplax membranes. Single channel currents were recorded from planar lipid bilayers containing the membrane channel proteins under investigation. The correlation functions are conveniently computed from single channel current records and yield information on E, the minimum number of entry/exit states into the open or closed aggregates. E gives a lower limit on the numbers of transition pathways between open and closed states. For the acetylcholine receptor, the autocorrelation analysis shows that there are at least two entry/exit states through which the open and closed aggregates communicate. The chloride channel fluctuates between three conductance substates, here indentified as C, M, and H for closed, intermediate, and high conductance, respectively. Correlation analysis shows that E is greater than or equal to 2 for the M aggregate, indicating that there are at least two distinct entry/exit states in the M aggregate. In contrast, there is no evidence for the existence of more than one entry/exit state in the C or H aggregates. Thus, these correlation functions provide a simple and general strategy to extract information on channel gating kinetics.

Animals↗
PubMed1984

The missing links between planning and budgeting. Keys to survival in an era of entrepreneurialism.

For hospitals to survive the challenges of their turbulent environment, they must build stronger links between their planning and budgeting processes. Hospitals have traditionally experienced a gap between their long-range plans and short-range budgets. This article examines the scope, nature, and causes of this gap; clarifies the need to bridge this gap; and then discusses three major initiatives (missing links) to bridge the gap. Implications of these missing links for the hospital's board, physicians, managers, and systems are also described.

Budgets↗