SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Sources and magnitude of errors in applying Prentice's rule in calculating decentration for spherical lenses were investigated. It was found that spherical aberration can be the only source of error in applying the rule. The overall magnitude of errors in effective prismatic effect is, however, clinically insignificant.
Maps of perceptual image quality were generated for a range of intraocular (IOL) tilts and decentrations, using a perceptually based metric i.e. the square integral (SQRI) metric. Maps were generated for a well-corrected eye, and for hyperopic (-0.1 mm) and myopic (+0.1 mm) image planes (for 2 and 4 mm pupils). These perceptually based results were compared with a standard optical measure (i.e. the equivalent SQRI for given spectacle power added at the cornea). The image quality changes in maps were small, but detectable (exceeding the perceptual just noticeable difference (jnd) or 1 jnd threshold). Clockwise (negative) tilt combined with decenter fell below the 'contrast reserve' modulation transfer functions (MTFs) for 0.25 and 0.5 D defocus, 4 mm pupil. These errors were larger than those found previously, probably because of the shape-factor of the IOL used. Pupil size contributed the largest drop in SQRI value, followed by clockwise tilt combined with decenter. Anticlockwise tilt with decenter produced image quality improvements for the hyperopic eye. Spot diagrams confirmed defocus and the balance of coma-like aberration and astigmatism as causes of the changes in SQRI values. The SQRI maps conveniently summarize imaging, and may be a useful tool in assessing image quality in eye modelling applications.
1. The ion distribution in the vas deferens of the guinea-pig was determined following reserpine treatment and decentralization, procedures known to increase the sensitivity of this muscle to drug stimulation.2. There were no significant changes in the estimated intracellular ion concentrations following the two procedures. The half-times of (42)K and (36)Cl effluxes were also unaltered.3. As far as ion content is concerned there is no basis for suggesting an altered resting membrane potential in supersensitive smooth muscle.
OBJECTIVES: A time-to-initial-stabilization model for out-of-hospital destinations of critically ill children (CICs) was developed. Application of this model to assess the impact of changes in different parameters of an emergency medical services for children (EMSC) system is described. METHODS: A computer model created a 2,500-square-mile community containing ten community hospitals (CHs) and one pediatric critical care center (PCC). Community hospitals capable of providing initial immediate stabilization of CICs were defined as emergency departments accepting pediatrics (EDAPs). Critically ill children were randomly selected in proportion to population densities across the modeled community. Time to initial stabilization (TIS) was defined as the time to arrival at either an EDAP or a PCC or time to arrival at a non-EDAP CH + travel time for a team from the PCC to the non-EDAP CH + preparation/dispatch (P/D) time. The following parameters of the model were varied and their effect on TIS was evaluated: location of CHs, location of PCC, primary destinations for CICs, percent of CHs meeting EDAP standards, out-of-hospital compliance with designated hospitals for CICs, P/D time, and ambulance speed. RESULTS: The computer model selected 1,000 CICs in accordance with the population densities of the community. The scenario with the shortest TIS was one in which every CH achieved EDAP designation (9.8 +/- 0.5 minutes). The scenario with the longest TIS involved a model in which every CIC was transported directly to the PCC (28.6 +/- 0.33 minutes). The number of EDAPs in a community and out-of-hospital compliance with use of EDAPs produced comparable effects on the TIS. Travel speeds had a direct effect on TIS but also exaggerated inefficiencies between scenarios. The P/D time had little effect on the TIS. CONCLUSIONS: An out-of-hospital destination model has been developed with the ability to modify multiple EMSC system variables. Application of this model demonstrates the shortest times to stabilization of critically ill children occur in systems that maximize the number of hospitals that meet EDAP standards and decentralize pediatric emergency care.
The ganglion blocking drug chlorisondamine given frequently and in gradually increasing doses over a period of time to adult rats causes the activity of choline acetyltransferase to fall in the postganglionic parasympathetic nerves of parotid glands. Such a "pharmacologically" decentralized gland was also found to have lost weight and to have developed a supersensitivity to chemical stimuli. All these phenomena are thought to be consequences of loss or reduction of secretory impulses from the central nervous system due to impaired ganglionic transmission.
Unilateral excision of the pelvic ganglion caused a loss in the number of AChE-positive nerves in the rat urinary bladder both on the operated side and on the contralateral side, thus indicating a bilateral intramural distribution of cholinergic nerves derived from the pelvic nerve. In the course of the subsequent observation period (3-28 days) the AChE-positive nerves increased in number and in staining intensity and further, the nerves became ramified and twisted. Similar events were found to occur in the urinary bladder decentralized on one side and denervated on the other. The morphological findings indicate an outgrowth of cholinergic nerves by collateral sprouting. These findings are discussed in relation to previous physiological studies.
Rhythmic motor pattern generation by the pyloric network in the lobster stomatogastric ganglion (STG) requires neuromodulatory inputs from adjacent ganglia. However, although suppression of these inputs by cutting the stomatogastric nerve (stn) causes the pyloric network to fall silent, network output similar to that expressed when the stn is intact returns after 3-4 days in organ culture. Intracellular recordings from identified pyloric dilator (PD) neurons indicate that the fundamental change underlying rhythm recovery resides with the intrinsic excitability of pyloric neurons themselves, since the prolonged absence of extrinsic modulatory inputs allows the expression of an endogenous oscillatory capability that is maintained in a strictly conditional state when these inputs are present. To examine whether gene transcription was involved in this change in neuronal behavior, we performed in vitro experiments in which the STG was exposed to the RNA-synthesis inhibitor actinomycin D (ACD). ACD (50 microM) incubation at the time of decentralization prevented subsequent reacquisition of PD neuron bursting, but the inhibitor was much less effective when applied at later postdecentralization times, suggesting that the recovery process arises from new protein synthesis triggered when modulatory inputs are first removed. Moreover, in the nondecentralized STG, trans-synaptic modulatory instruction may sustain the conditional pyloric network phenotype by continuously regulating expression of genes responsible for intrinsic neuronal rhythmogenesis.
Grassé [26] coined the term stigmergy (previous work directs and triggers new building actions) to describe a mechanism of decentralized pathway of information flow in social insects. In general, all kinds of multi-agent groups require coordination for their effort and it seems that stigmergy is a very powerful means to coordinate activity over great spans of time and space in a wide variety of systems. In a situation in which many individuals contribute to a collective effort, such as building a nest, stimuli provided by the emerging structure itself can provide a rich source of information for the working insects. The current article provides a detailed review of this stigmergic paradigm in the building behavior of paper wasps to show how stigmergy influenced the understanding of mechanisms and evolution of a particular biological system. The most important feature to understand is how local stimuli are organized in space and time to ensure the emergence of a coherent adaptive structure and to explain how workers could act independently yet respond to stimuli provided through the common medium of the environment of the colony.
Though there is a significant literature which notes that physicians are fast becoming organizational members, there has been little research evidence to suggest that the adoption of new management models have actually facilitated their involvement. This study sought to examine whether a conscious effort at decentralizing decisions at the clinical unit level would actually result in increased involvement of physicians and other clinicians in decision-making at that level. Two major surveys examining individual roles and responsibilities and unit relationships with other units were conducted, at two points in time, in a large Canadian tertiary care centre. Results suggest that physicians had experienced an increase in administrative discretion. There was an overall increase of many groups in influencing clinical unit decisions with a perceived decrease in senior management influence in budget administration at the unit level. Lessons learned in conducting this type of research are described.
This article presents a practical demonstration of a decentralized pharmacy system improving the quality of pharmaceutical services. The authors explain the working system of a satellite pharmacy in one of the pavilions of the Hospital de la Santa Creu i Sant Pau in Barcelona, Spain. Clinical pharmacists working in this satellite become deeply involved in drug information, quality control programs, pharmacokinetics, patient education, research, and teaching activities.
In this article, we investigate developments in Danish health care policy. After a short presentation of its historical roots, we focus on the decades after the administrative reform of 1970, which shaped the current decentralized public health care system. Theories of path dependency and institutional inertia are used to explain the relative stability in the overall structure, and theories of policy process and reform are used to discuss gradual changes within the overall framework. Although comprehensive reforms have not taken place in Denmark, many gradual changes may pave the way for more radical changes in the future. The political climate currently seems to be more favorable toward structural reform than in the past.
Interactions among the nervous, neuroendocrine, and immune systems render host defenses highly sensitive to autonomic over- or understimulation. Persons with quadriplegia experience decentralization of directly innervated immune tissues and neuroendocrine axis dysregulation, immobilization deconditioning, heightened exposure to immune suppressing xerobiologicals, and psychic and nonpsychic stressors differing from those of nondisabled cohorts. When compared with matched nondisabled controls, young survivors of quadriplegia have reduced CD4:CD8 ratios, suppressed proliferative responses to mitogen challenge, reduced number and cytotoxicity of CD3-CD56+ (NK) cells, and elevation of the soluble IL-2 receptor. Deviations from control values are typically observed in persons with injuries higher than sympathetic outflow, suggesting a cause related to autonomic dysfunction. Cycling exercise performed by persons with quadriplegia using computer-sequenced electrically stimulated contraction of the quadriceps, hamstring, and gluteus muscle groups fails to provoke an archetypical leukocytosis, but transitionally elevates NK cell number and cytotoxicity lasting one-half hour after exercise. These findings show that the immune system of persons with quadriplegia is selectively responsive to exercise challenge. As opportunistic infections of the urinary tract, lungs, and skin are major causes of morbidity in survivors of quadriplegia, these observations may identify a treatment through which their host defenses can be fortified.
This paper discusses certain historical and theoretical aspects pertaining to the concepts of decentralization, local autonomy, and citizens' participation in studies on the reorganization of health services. Further studies should be undertaken to identify determinants of and limits to the reorganization of health services, greater local autonomy and citizens' participation. Various hypotheses and future courses of study are proposed.
This piece analyzes the funding of the public Unified Health System (UHS) in the state of Mato Grosso, Brazil, in order to identify the model of care that has been taking shape there since 1994. We studied 16 municipalities, selected according to their size, degree of involvement with the UHS, and socioeconomic and health conditions. We found that between 1994 and 1998 there were large increases in health spending, due to higher municipal expenditures and to rising intergovernmental transfers for outpatient care. However, the health care system taking shape in a large number of Mato Grosso municipalities is increasingly focused on an individual, curative, specialized, and highly technological type of care. Indicative of this trend is the fact that the biggest increases in spending for outpatient care--up to 300% in some municipalities--have come from diagnostic and therapeutic procedures that are of medium or high complexity. Since the resources for health care are limited, and since the model of care adopted by many municipalities continues to shift resources from primary health care to more complex procedures, we believe that the financial viability of the Unified Health System is coming into question. Although this study was limited to the state of Mato Grosso, other Brazilian municipalities are no doubt facing similar situations. The same is probably true for municipalities in other South American countries that have adopted decentralization of the health care system as one of the strategies for State reform.
Health sector reform in Bolivia is based primarily on the principles of decentralization and equity, and with the objectives of improving quality and of expanding health services coverage in rural and low-income areas of the country. As an experiment in reform, the Bolivian Ministry of Health and Social Welfare, the department of La Paz, and the municipality of El Alto signed an agreement with a nongovernmental organization (NGO), transferring to the NGO the overall management of one of the health services networks in El Alto. The transfer was based on a management contract that had process and outcome indicators for the network. A year after implementation began, the preliminary results suggest that through the agreement the quality of management and services has improved, health services coverage has expanded, and the network's primary care services have been strengthened. Bed occupancy rates are generally very low in secondary hospitals in Bolivia, with that figure being just 43% in the department of La Paz in 1999. However, in the second 6 months of operation of the El Alto network the occupancy rate for the network's hospital reached 84%. Between the first 6 months of 1999 and the same period in 2000, outpatient consultations increased by 55% in the network (83% in the hospital and 18% in the network's primary care centers). Over that same period, institutional deliveries increased by 41% and the percentage of deliveries in the primary care centers grew from 5% of the total to 9%. A recent user survey found that 87% of the people receiving care in the network felt highly satisfied with the service they had received, and 75% of the persons surveyed said they would recommend the service to others. These are not typical data for health services in Bolivia. This pilot effort suggests that a change in the organization and management of a health services network, with a separation of the roles of purchaser and provider, combined with management based on results and with community participation in the process, can improve the quality and efficiency of those health services, stimulate demand for them, and increase user satisfaction.
This paper describes the Course on Decentralized Management of Human Resources in Health Care, which is an Internet-based distance learning program to train and provide continuing education for health care professionals. The program is an initiative of the Pan American Health Organization, and it was organized in response to the growing need for self-reliant professionals who can constantly upgrade their knowledge without having to leave their place of work. The proposed model promotes an educational process that brings together theory and practice in realistic and relevant contexts and that maximizes the participation of students, both individually and in groups. The program has been evaluated in pilot studies in Brazil, Chile, and Peru. Following these assessments, the course has been adapted to facilitate its implementation and to adjust its contents to fit each country's circumstances.
OBJECTIVES: To determine the per-patient-per-month (PPPM) cost of a decentralized outpatient pharmacy anticoagulation service (OPAS) in patients with chronic atrial fibrillation (AF) who were maintained on warfarin sodium therapy in a managed care setting, to compare the annual costs versus the risk for stroke, and to assess the quality of the anticoagulant management. METHODS: Data were collected retrospectively from clinical, research, and administrative claims databases. Patient demographic data were stratified to include age and risk factors for stroke. Inclusion criteria for the study were adult patients (>18 years) who were maintained on chronic warfarin therapy with a diagnosis of AF (diagnosis code 427.31) and continuously enrolled during calendar year 2000. The cost analysis included the personnel cost of clinical pharmacy specialists, direct and indirect cost of laboratory tests for international normalized ratios (INR), and anticoagulant (warfarin plus bridge therapy with a low molecular weight heparin) drug cost and dispensing fee. The percentage of INR values within or near target was used to evaluate the effectiveness of the service. RESULTS: A total of 97 patients on chronic warfarin therapy for AF were identified for cost analysis. The demographics for these patients included the following: 71% were male, with 32% of the patients over the age of 75 years, and 60% had 1 or more identifiable risk factors for stroke. Utilizing established criteria, 80.4% of the sample was considered to be at high risk for ischemic stroke. A majority of the patients (94.8%) had nonvalvular disease, with an INR goal in the range of 2 to 3 in 91.8% of the cases. The PPPM cost for the OPAS monitoring service was $51.25, distributed as $13.78 (27%) in personnel costs for monitoring pharmacists, $18.38 (36%) for lab tests, and $19.09 (37%) for anticoagulant drug costs. These costs did not significantly differ among patient groups with various risks for ischemic stroke. For nonvalvular AF patients, the percentage of INR values within each individual patient.s specific INR goal range was 60.4%; the percentage within or near goal was 74.6%. CONCLUSION: The average PPPM cost for pharmacist and laboratory monitoring as well as anticoagulant medication for CY 2000 was estimated to be $51.25. The annual costs were comparable among AF patients with different risks for ischemic stroke. The percentage of INR values within the individual patient.s stated target goal was 60.4%. Effective monitoring to maintain patients within their target INR goal is relatively inexpensive compared with the cost of complications such as ischemic stroke or intracranial bleeding.
Observations of a publicly-financed system for the medical care of a large number of persons with chronic diseases have been made over seven years. The system combines decentralized, nurse-staffed neighborhood clinics, operated by a public health department, with a central referral clinic for consultations and the management of complicated problems. After seven years in the chronic disease program 55% of 1,004 patients with diagnoses of diabetes mellitus, hypertension, and cardiac diseases were still receiving care, 19% had died, and 26% had been lost to the program. In the seventh year, the mean diastolic blood pressure in hypertensives was 84 mm Hg and the mean serum glucose in diabetics was 203 mg/dl. For the group under care, hospital days/1000/year were 74% of the rate during the year before referral to the program and out-patient visits/1000/year were approximately the same as before referral. However, two-thirds of the visits, formerly made to a public hospital, were now being made to neighborhood clinics. The system appears to be an effective method of providing medical services for persons who formerly used the public hospital as their source of outpatient care.