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At least 829 records · Page 46Linked to original sources
PubMed1998

Diagnostic delay in breast disease: a system analysis of a public urban hospital.

OBJECTIVE: To analyze the diagnostic process in 146 women referred to a breast clinic in an urban setting between January 1, 1994, and December 31, 1996. DESIGN: We devised the "diagnostic delay index (DDI)," defined as the time between the medical system's awareness of a diagnostic need and the completion of the diagnostic process. The time awaiting breast clinic consultation and the diagnostic events experienced--including clinic visits, imaging studies, and biopsies--were recorded. We stratified patients in 2 pathways (palpable masses and mammogram-identified lesions) and by benign or malignant outcome. RESULTS: Patients in pathways 1 (n = 85) and 2 (n=61) had a mean (+/-SD) DDI of 68.4 (+/-46.9) days and 71.9 (+/-35.2) days, respectively. Patients in both pathways who had a malignant outcome had a significantly lower DDI than those who had a benign outcome (47.5+/-30.9 days vs 78.6+/-42.6) (P<.001); this advantage was most pronounced in patients with palpable lumps. The average patient waited more than 3 weeks for both an initial clinic consultation and operating room access. Quartile analysis of the DDI revealed statistically significant differences in clinic access time, number of visits, diagnostic events per visit, and operating room access time. Regression analysis demonstrates the relationship between DDI and measured process variables: DDI= -21.11+0.09 age+1.86 pathway-12.18 outcome+1.08 clinic access+11.91 visits+0.94 operating room access (R2=61.5%). CONCLUSIONS: In a public hospital, diagnostic delay is related to inadequate access to surgical consultation and a delay in operating room access. Regression analysis demonstrates the relationships between these components of system diagnostic delay and suggests strategies for reducing the DDI.

Adolescent↗
PubMed1997

[Lymphogranulomatosis: a systems analysis of the age- and sex-related characteristics of hemopoiesis and metabolism].

72 clinical and laboratory features were analyzed on the IBM PC 486 for 126 new cases of lymphogranulomatosis prior to treatment. Myelograms were found to vary with sex and age of the patients demonstrating close relations between hemopoiesis and processes in the lymph nodes. In males maturation of myeloid elements KM was inhibited, though they had more monocytes KM. These monocytes got more numerous in unfavorable histological variants and generalization. Lymphopenia and monocytosis were more pronounced in patients under 30 becoming more severe in generalization and intoxication. Age-related changes in cholesterol in lymphogranulomatosis patients were abnormal: in older patients cholesterol was low. This phenomenon is extremely unfavorable. The findings elucidate prognostic value of sex and age in lymphogranulomatosis and suggest a hypothesis that monocytes (macrophages) and secreted by them monokines are responsible for specific intoxication, neutrophilia and lymphopenia. Berezovsky-Sternberg cells may be hybrids of macrophages and B-lymphocytes.

Adolescent↗
PubMed1988

Nonlinear systems analysis of the hippocampal perforant path-dentate projection. II. Effects of random impulse train stimulation.

1. Nonlinear systems analytic techniques were used to characterize transformational properties of the network of neurons activated by perforant path input to the rabbit hippocampus. Trains of 4,064 impulses with randomly varying interimpulse intervals were used to stimulate perforant path fibers, and amplitudes of evoked dentate granule cell population spikes were measured. Interimpulse intervals of the random stimulus train were determined by a Poisson distribution with a mean interimpulse interval of 500 ms, and with intervals ranging from 1 to 5,000 ms. The response of dentate granule cells to this stimulation was assumed to reflect activity in the larger hippocampal network, because other subpopulations of neurons activated monosynaptically and polysynaptically within the hippocampal formation contribute to granule cell excitability through multiple feedforward and feedback pathways. System properties were characterized both for halothane anesthetized and chronically implanted, unanesthetized preparations. 2. Second-order kernel analysis showed that population spike amplitude was highly dependent on interimpulse interval. When population spikes of all latencies were included in the same analysis, stimulation impulses produced near-total suppression of spike amplitude when they were preceded 10-20 ms by another impulse in the train. Spike suppression extended to approximately 50 ms and was inversely related to length of the interimpulse interval. Suppression of granule cell response to intervals within the range of 10-50 ms was not influenced by halothane anesthesia. 3. Interstimulus intervals greater than approximately 50 ms resulted in a facilitation of population spike amplitude, with maximum facilitation occurring in response to intervals of 90-100 ms. The magnitude of maximum facilitation was significantly greater for anesthetized (129%) than for unanesthetized (74%) preparations. The range of intervals resulting in facilitation for unanesthetized animals could extend to 1,000-1,100 ms (average range, 61-714 ms). This was much greater than observed for population spikes recorded from anesthetized animals (50-364 ms), which exhibited suppression in response to intervals of approximately 300-700 ms. 4. Further analysis revealed that the nature of nonlinearities in population spike amplitude may depend on spike latency. For example, population spikes of "short" latency (3-4 or 4-5 ms, depending on the animal) exhibited only facilitation in response to interstimulus intervals of 1-4 ms.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗
PubMed2001

Microfabricated capillary array electrophoresis DNA analysis systems.

Microfabricated "laboratory-on-a-chip" systems are revolutionizing all aspects of genetic analysis. The development of capillary array electrophoresis (CAE) microchannel plate devices makes possible the performance of 96 or more high-speed separations in parallel on a single wafer-scale device. The fluorescently labeled DNA samples are detected within the microchannels with a novel four-color rotary confocal fluorescence scanner. The capabilities of this system for genotyping are demonstrated through multiplex separations of short tandem repeat and hereditary haemochromatosis allele-specific amplicons. Furthermore, with newly developed folded channel designs that maintain high resolution, these CAE microplate systems are used to perform 96 high-quality DNA sequencing separations in parallel to approximately 500 bases per capillary in less than 30 min. These densely packed microfabricated device technologies will facilitate the even more rapid collection of vast amounts of genetic data in the future.

Base Sequence↗
PubMed2004

A simple computer-based measurement and analysis system of pulmonary auscultation sounds.

Listening to various lung sounds has proven to be an important diagnostic tool for detecting and monitoring certain types of lung diseases. In this study a computer-based system has been designed for easy measurement and analysis of lung sound using the software package DasyLAB. The designed system presents the following features: it is able to digitally record the lung sounds which are captured with an electronic stethoscope plugged to a sound card on a portable computer, display the lung sound waveform for auscultation sites, record the lung sound into the ASCII format, acoustically reproduce the lung sound, edit and print the sound waveforms, display its time-expanded waveform, compute the Fast Fourier Transform (FFT), and display the power spectrum and spectrogram.

Algorithms↗
PubMed1997

Dynamic-system analysis of opponent relationships in collective actions in soccer.

The aim of this study was to examine the contribution of the systemic approach to the analysis of play in team sports. We first focus on the theory of dynamical systems and consider the interactions between the main variables of the different components of systems and subsystems in soccer. In team sports, these variables represent fluctuating conditions, which momentarily constrain the organization of action for the players. Thus changes in the momentary configuration of the game have to be examined in the light of previous configurations, the outline of the defensive strategy and the tactical choices involved. To study this problem, we analyse the antecedents of goals in soccer. A procedure is proposed which analyses transitions between configurations of play, thus allowing time to be taken into consideration when studying the evolution of a match. To illustrate the use and benefit of the analytic procedure, two goals are described in terms of dynamic configurations of play and opportunity of choices made by attackers.

Goals↗