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PubMed1994

[Training of animals with hypoinsulinemia: systems analysis].

Experiments on rabbits and rats with dithizone- and streptozotocin- induced (stz) diabetes were made to study the learning characteristics in animals with hypoinsulinemia. The analysis of operant feeding training of rabbits showed their higher searching behavior and more successful learning in hypoinsulinemic than those in intact animals. The behavior structure differences could be removed by an injection of insulin one hour before the testing. In experiments on rats with electroshock avoidance training some groups with different learning characteristics were distinguished. Searching activity of stz-rats was lower than that of controls, and the most of stz-rats belonged to a lazy group. The results are discussed according to Anokhin's theory of the functional system.

Animals↗
PubMed1993

Integrated systems analysis of sow replacement rates in a hierarchical swine breeding structure.

Sow replacement rates in a three-tiered breeding structure were investigated for a 10-yr planning horizon using a stochastic life-cycle swine production model. Market hogs were produced in a three-breed static crossing program and marketed on a liveweight basis. Growth and reproductive traits of individual pigs were simulated using genetic, environmental, and economic parameters. Sows were culled after a maximum of 1, 5, or 10 parities. Systems were defined by maximum sow age at culling and included combinations of 1- and 5-parity nucleus and 1-, 5-, and 10-parity multiplier and commercial tiers. Economic response to index selection was considerable for all culling alternatives with yearly increases in system profits ranging from $1.06 to 1.44 for each commercial hog marketed. When sows were culled after one parity in nucleus, multiplier, and commercial tiers, respectively (1,1,1), annual changes in net returns and all cost measures were 40 to 50% larger than responses in systems with lower sow replacement rates. Based on 10-yr averages for net returns, systems with low multiplier- and commercial-level replacement rates were more profitable than systems with higher replacement rates. The most profitable system (5,10,10) differed from the least profitable system (1,1,1) by more than $10 per pig, but when the (1,1,1) system was excluded, the range was only $3 per pig. The system with lowest replacement rates supported 3,388 more multiplier and 34,151 more commercial sows from a 750-sow nucleus level than the (1,1,1) system. Output from the two extremes differed by > 664,000 commercial market hogs sold.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Systems analysis in hospital management].

Organization is one of the most important concepts for contemporary society. Whereas in recent years industry and the private services field have adopted management criteria to establish aims and methods, and to manage their organizations, the same is not true for public services. So in this area, particularly in health services, the need for a managerial type of organization is particularly evident. The basic change in the approach to the solution of organization problems, in accordance with a management type criterion, is the substitution of the traditional analytical approach with an assessment of systemic type that examines relations and interactions between the various components of an organization. Of the various methods proposed, one conceptual instrument that permits a management-type analysis of an organization is the "7S" method. An approach of this type may be particularly useful for the evaluation of an extremely complex structure like that of a hospital. According to this method, the interactions between strategy, structure, systems, staff, style, skills, and system of prevalent values of the hospital's organization structure are analysed with the purpose of improving their management.

Hospital Administration↗
PubMed2006

Metabolic futile cycles and their functions: a systems analysis of energy and control.

It has long been hypothesised that futile cycles in cellular metabolism are involved in the regulation of biochemical pathways. Following the work of Newsholme and Crabtree, a quantitative theory was developed for this idea based on open-system thermodynamics and metabolic control analysis. It is shown that the stoichiometric sensitivity of an intermediary metabolite concentration with respect to changes in steady-state flux is governed by the effective equilibrium constant of the intermediate formation, and the equilibrium can be regulated by a futile cycle. The direction of the shift in the effective equilibrium constant depends on the direction of operation of the futile cycle. High stoichiometric sensitivity corresponds to ultrasensitivity of an intermediate concentration to net flow through a pathway; low stoichiometric sensitivity corresponds to super-robustness of concentration with respect to changes in flux. Both cases potentially play important roles in metabolic regulation. Futile cycles actively shift the effective equilibrium by expending energy; the magnitude of changes in effective equilibria and sensitivities is a function of the amount of energy used by a futile cycle. This proposed mechanism for control by futile cycles works remarkably similar to kinetic proofreading in biosynthesis. The sensitivity of the system is also intimately related to the rate of concentration fluctuations of intermediate metabolites. The possibility of different roles for the two major mechanisms within cellular biochemical regulation, namely reversible chemical modifications via futile cycles and shifting equilibrium by macromolecular binding, are discussed.

Biological Clocks↗
PubMed2005

Systems analysis of stress and positive perceptions in mothers and fathers of pre-school children with autism.

Systemic analyses of psychological functioning in families of children with autism have typically shown that parents report different experiences (e.g., stress) and that siblings may also be affected. The purpose of the present research was more explicitly to address relationships between child, partner, and parent variables. Parents of 48 children with autism (41 mother-father pairs) reported on child characteristics, and their own stress and mental health. Mothers were found to report both more depression and more positive perceptions than fathers. Regression analyses revealed that paternal stress and positive perceptions were predicted by maternal depression; maternal stress was predicted by their children's behavior problems (not adaptive behavior or autism symptoms) and by their partner's depression. The future testing of the mechanisms underlying these results is discussed. In addition, the need is emphasized for more systemic analyses to understand the psychological functioning of children with autism and their siblings and parents.

Adult↗
PubMed1978

The oscillating peroxidase-oxidase reaction in an open system. Analysis of the reaction mechanism.

1. The oscillations in the peroxidase-oxidase reaction in an open system with NADH as the hydrogen donor are caused by the reaction starting and stopping at critical concentrations of the substrates O2 and NADH. The existence of such critical concentrations is typical of branched chain reactions. 2. The critical concentrations of O2 and NADH that determine the initiation of the reaction are mutually dependent. 3. The branching reactions that determine these critical concentrations involve compounds I and II. 4. Superoxide may be involved in the branching reactions by reacting with NADH and ferriperoxidase. At pH 5.1 the rate constant for the latter reaction is determined as 1.5 . 10(5) M-1 . s-1, whereas for the former reaction only an upper limit for the rate constant of 3.5 . 10(4) M-1 . s-1 could be estimated. These relatively low rate constants suggest that alternative branching reactions may also be involved.

Kinetics↗
PubMed1981

A systems analysis of psychobiology and behavior therapy. Implications for behavioral medicine.

This article examines some basic principles of systems theory and applies them to the integration of psychobiology and behavior therapy in the evolution of behavioral medicine. Using the concepts of whole/part relationships, level and emergent property, and self-regulation and disregulation, it is proposed that all behavioral therapies involve psychobiological processes, and therefore, indirectly impinge on physical health. It is argued that the distinction between behavior and biology is one of level, and, therefore, behavioral therapies are ultimately biobehavioral therapies having biobehavioral consequences. It is proposed that contrary to traditional reductionistic logic, modern advances in biology are providing strong justification for the importance of including psychological methods in treating diseases manifested at the biological level. Various clinical examples are used to demonstrate how systems theory can be applied to differential diagnosis and treatment, computing cost/benefit ratios of different treatments, and conducting comprehensive clinical research and evaluation. Assessing the interaction of biological, psychological, and social treatment modalities becomes the hallmark of responsible patient care. Implications of the systems conception of behavioral medicine for collaboration among health care providers, the training of future clinicians in different disciplines, and policy decisions regarding the larger social consequences of health care are considered.

Behavior Therapy↗
PubMed1992

Three-dimensional computed tomographic imaging of the pelvicaliceal system: analysis of factors influencing image quality.

We analyzed 3-dimensional (3D) computed tomographic images of the pelvicaliceal system obtained in 25 patients after opacification of the collecting system by retrograde ureteric or intravenous (IV) infusion of sodium iothalamate. 3D images were reconstructed using the data from nonoverlapping 5-mm sections taken on an Elscint 2400 scanner. Factors contributing to poor image quality were: artifacts caused by contrast in the collecting tubules, underfilling or overdistension of the pelvicaliceal system with contrast, movement of the patient and severe hydronephrosis. Satisfactory 3D images of the pelvicaliceal system can be obtained by retrograde ureteric infusion of 5% w/v sodium iothalamate at 20 cm H2O, or by IV injection of 50 ml of 70% w/v sodium iothalamate. Abdominal compression should be applied 10-15 min after the IV injection of contrast, and the computed tomographic examination should commence 20-30 min after the injection. It is imperative that the patient lie completely still and breathe normally to avoid movement of the kidneys. 3D computed tomographic imaging of the pelvicaliceal system may become a valuable adjunct to the preoperative planning and performance of percutaneous nephrolithotomy.

Adolescent↗
PubMed2004

[Clinical manifestations and treatment of melanoma of the central nervous system: analysis of 15 cases].

OBJECTIVE: To investigate the diagnosis and treatment of melanomas of the central nervous system. METHODS: The clinical data, including presentation, treatment, operative finding, histological diagnosis and prognosis of 15 patients with melanomas of central nervous system who underwent surgery 1996 - 2003 were reviewed. RESULTS: There were 12 cases of intracranial melanoma and 3 cases of spinal cord melanomas. No distinctive symptoms occurred in these patients. Total resection was achieved in 5 cases, and subtotal resection in 10 cases. Histological examination showed melanoma in 10 cases, meningeal melanocytoma in 4 cases, and amelanotic melanoma in 1 case. Ten cases were followed up for 3 months to 9 years. Among the 10 cases only 1 survived. CONCLUSION: Melanoma of the central nervous system is an extremely rare tumor and difficult to get correct preoperative diagnosis. Microsurgery combined with radiotherapy or gamma-knife therapy is recommended. The prognosis is very poor.

Adolescent↗
PubMed2005

Continuous on-line concentration based on dynamic pH junction for trimethoprim and sulfamethoxazole by microfluidic capillary electrophoresis combined with flow injection analysis system.

A novel, rapid and continuous on-line concentration approach based on dynamic pH junction for the analysis of trimethoprim (TMP) and sulfamethoxazole (SMZ) by microfluidic capillary electrophoresis (CE) combined with flow injection analysis is developed in this paper. Stacking is due to decreases in the velocity of analytes when migrating from the low-pH sample zone (sample was dissolved in 50 mM HCl) to a relatively high-pH buffer (30 mM phosphate buffer, pH 8.5) filled in the capillary. This results in 2.9-4.7-fold improvement in concentration sensitivity relative to conventional capillary electrophoresis methods. The separation could be achieved within 2 min and sample throughput rate can reach up to 38 h(-1).

Electrophoresis, Capillary↗
PubMed2000

[Chemicals toxic to the olfactory system. Analysis and description].

AN IMPORTANT PROBLEM: Occupational exposure to chemical products can have toxic effects on the olfactory system. An important number of patients have experienced olfactory disorders subsequent to the development of the chemical industry and atmospheric pollution. EPIDEMIOLOGY DATA: Straightforward data are difficult to collect because several cofactors other than the toxic product are involved. Two lists of toxic products can be made. The first list includes products for which scientific data is available and the second products for which data is lacking. Olfactory tests also differ between authors and countries. TWO TYPES OF TOXICITY: Acute, accidental toxicity is evidenced by the lesions caused by inhalation of high-doses of strongly toxic agents. Chronic intoxication caused by lower concentrations of these inhaled agents does not produce a trigeminal reflex leading to a modified respiratory rate reducing the airborne aggression. APPROXIMATIONS: Clinical data describing the olfactory toxicity of certain industrial and chemical compounds are very significant but often cannot prove a cause and effect relationship. Data obtained with experimental models in rodents are difficult to extrapolate to humans.

Air Pollutants, Occupational↗
PubMed1992

[Magnetic resonance tomographic diagnosis of vascular processes in the vertebrobasilar system--analysis of 35 of our own cases and a literature review].

35 patients with abnormalities of the vertebrobasilar system were studied via magnetic resonance imaging (11 saccular aneurysms, 10 vascular malformations, 9 basilar arteries with dolichoectasia, 5 thromboses of the vertebral or basilar artery). The two smallest aneurysms of the basilar top had a diameter of 2-3 mm. Most vascular malformations could be differentiated by typical MRT symptoms. All 5 cavernous angiomas were negative in angiography (cryptic). The shape and size of the basilar artery and its relationship to the third ventricle were best demonstrated on coronal slices. Flow-related intraluminal loss of signal allows a differentiation between vascular perfusion and thrombosis already on plain images (partial) thrombosis and artery dissection can be differentiated from flow effects based on identical findings in at least two planes or additional gradient echo images.

Adult↗
PubMed1998

Factors influencing human sperm kinematic measurements by the Celltrak computer-assisted sperm analysis system.

This study examines the effect of varying several factors, both extrinsic and technology-dependent, on the reconstruction of human sperm trajectories and the derived kinematic measurements using videotapes and the Motion Analysis Celltrak/S instrument. In semen samples from normal healthy men, curvilinear (VCL) and straight line velocities (VSL) were found to increase 1.5-fold, and linearity (LIN) of trajectories and amplitude of lateral head displacement (ALH) increased 1.25-fold when the temperature of analysis was raised from 24 to 37 degrees C. Only VCL and VSL were found to increase significantly between 24 and 37 degrees C for sperm samples selected by Percoll gradient and incubated in a capacitating medium. An analysis chamber of 20 microm depth was found to be adequate for seminal sperm samples while for Percoll-selected sperm samples the analysis in a 50 microm depth provided the highest proportions of spermatozoa with the highest VCL and the largest ALH. The grey level detection threshold required careful adjustment: using a threshold lower than the optimal threshold produced spurious sperm trajectories for seminal sperm samples and rejected some trajectories for Percoll-selected sperm samples. Definition of the appropriate frame rate and maximum burst speed was critical for valid trajectory reconstruction and therefore adequate derived kinematic measurements. Optimal values of these parameters were found to be 30 Hz and 400 microm/s for seminal spermatozoa and 60 Hz and 700 microm/s for selected spermatozoa. The optimal values of 'ALH path-smoothing factor' used to calculate average path and ALH were 5-10 points for seminal spermatozoa analysed at 30 Hz and 15-20 points for selected spermatozoa analysed at 60 Hz. We propose a set of standard conditions for reliable kinematic analysis of human spermatozoa using the Celltrak/S system.

Centrifugation, Density Gradient↗
PubMed1999

[The research of distributed HRV analysis system based on DCOM].

This article introduces the meaning of Distributed Component Object Model(DCOM), which used network communication protocol to replace the local process communication to reach the aim of Distributed Computing, then it discusses the significance of HRV analysis, and finally it presents the system we developed.

Computer Communication Networks↗
PubMed2002

Healthcare information systems: analysis of healthcare software.

The need to manage medical information in healthcare delivery requires that information technology be optimized in diagnosing disease; in planning and administering treatment; and in monitoring patient outcomes, services, and costs. The goals of this article are twofold: (1) to identify healthcare-specific software that addresses specific parameters set forth by the World Health Organization (WHO) for healthcare information systems and (2) to identify issues that managers should keep in mind when choosing an integrated information systems software package. For our analysis, we gathered, through Internet research, information about more than 400 software products from more than 200 companies.

Decision Making, Organizational↗
PubMed2004

Image analysis system for acquiring three-dimensional contour of foot arch during balanced standing.

Compared to the X-ray approach, footprint analysis is a non-radiation and more viable method for clinical assessment of the medial longitudinal arch of the foot. In this study, we have designed an optical footprint acquisition system that consists of a digital camera and two pieces of glass, each with four load cells under each corner. When the subject stands on the transparent force plates, the digital camera is triggered, photographing the soles of the feet at the moment when both feet bear approximately at the same weight. A blue gel is placed between the foot and the force plate to enhance the contrast between sole and background. Based on the relationship between the brightness of the image and the thickness of the gel, the three-dimensional (3D) structure of the arch can be reconstructed which can provide more representative information than a conventional footprint image, with its low resolution and easy smearing.

Foot↗