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PubMed1997

Distribution of choline acetyltransferase immunoreactivity in the brain of anuran (Rana perezi, Xenopus laevis) and urodele (Pleurodeles waltl) amphibians.

Because our knowledge of cholinergic systems in the brains of amphibians is limited, the present study aimed to provide detailed information on the distribution of cholinergic cell bodies and fibers as revealed by immunohistochemistry with antibodies directed against the enzyme choline acetyltransferase (ChAT). To determine general and derived features of the cholinergic systems within the class of Amphibia, both anuran (Rana perezi, Xenopus laevis) and urodele (Pleurodeles waltl) amphibians were studied. Distinct groups of ChAT-immunoreactive cell bodies were observed in the basal telencephalon, hypothalamus, habenula, isthmic nucleus, isthmic reticular formation, cranial nerve motor nuclei, and spinal cord. Prominent plexuses of cholinergic fibers were found in the olfactory bulb, pallium, basal telencephalon, ventral thalamus, tectum, and nucleus interpeduncularis. Comparison of these results with those obtained in other vertebrates, including a segmental approach to correlate cell populations, reveals that the cholinergic systems in amphibians share many features with amniotes. Thus, cholinergic pedunculopontine and laterodorsal tegmental nuclei could be identified in the amphibian brain. The finding of weakly immunoreactive cells in the striatum of Rana, which is in contrast with the condition found in Xenopus, Pleurodeles, and other anamniotes studied so far, has revived the notion that basal ganglia organization is more preserved during evolution than previously thought.

Animals↗
PubMed2005

Distribution of Crenosoma vulpis and Eucoleus aerophilus in the lung of free-ranging red foxes (Vulpes vulpes).

Crenosoma vulpis and Eucoleus aerophilus are nematode parasites that can cause verminous pneumonia in wild carnivores. There is a paucity of information regarding the distribution of parasites in the lungs and the relationship between histopathological and parasitological diagnoses in naturally infected foxes. The objectives of this study were: first, to study the lobar and airway distribution of C. vulpis and E. aerophilus in wild red foxes and second, to investigate the relationship between fecal and histopathological diagnoses. Samples from 6 sites of the lung and fecal contents were obtained from 51 wild foxes in Prince Edward Island. By fecal examination, 78.4% of wild foxes tested positive for C. vulpis and 68.6% for E. aerophilus. In contrast, 66.6% and 49% of foxes had histopathological evidence of C. vulpis and E. aerophilus in the lungs, respectively. Anatomically, C. vulpis was observed in the small bronchi and bronchioles of all pulmonary lobes whereas E. aerophilus was restricted to the large bronchi and the caudal lobes. Affected airways exhibited severe epithelial glandular hyperplasia and bronchiolar mucous metaplasia. It was concluded that C. vulpis is widely distributed in airways of all pulmonary lobes, whereas E. aerophilus is mainly restricted to the bronchi of caudal lobes. Also, this study showed that histological examination of lung underestimates the infection with E. aerophilus.

Animals↗
PubMed1999

Assessment of ambulance response performance using a geographic information system.

The accessibility, distribution and utilisation of emergency medical services are important components of health care delivery. The impact of these services on well-being is heightened by the fact that ambulance resources must respond in a reliable and timely manner to emergency calls from demand areas. However, many factors, such as the unavailability of an ambulance at a center closest to a call, can adversely influence response time. This paper discusses the design and implementation of a framework developed in a Geographic Information System for assessing ambulance response performance. A case study of ambulance response in three communities in Southern Ontario, Canada is presented that allows easy and rapid identification of anomalous calls that may adversely affect overall operating performance evaluation. Extensions of the framework into a fully fledged service deployment and planning decision support system are discussed.

Ambulances↗
PubMed1995

Measurement of field distributions in ultrasonic cleaning baths: implications for cleaning efficiency.

The information available on ultrasound field distributions in cleaning baths is limited. Two techniques capable of providing this information have been investigated. The first employs a thermistor probe coated with ultrasound absorbing material and uses the rate of temperature rise when the ultrasound is switched on as a measure of local energy density. A motorized scanning frame has been used to map field distributions in three dimensions using the technique. The second technique, the Sarvazyan (dye/paper) method, uses Astralux paper placed in a bath containing an aqueous solution of methylene blue dye. More dye is transferred to the paper in areas where the ultrasound field is most intense. Pockets of gas are trapped in pores in the paper which provide additional nuclei for initiation of cavitation events and these produce small areas of intense staining about 1 mm in diameter, which are related to cavitational activity. The techniques reveal non-uniformities both in the field distribution and in the pattern of cavitational activity in ultrasound cleaning baths. Methods for assessing ultrasound field distributions are required in order to ensure that energy densities are sufficient to initiate cleaning action throughout ultrasonic cleaning baths.

Biophysical Phenomena↗
PubMed2005

Development of a procedure for the sequential extraction of substances binding trace elements in plant biomass.

This work investigates how the amounts of some important substances in a plant, and their behaviour inside the plant, depend on the levels of stress placed on the plant. To this end, model plant spinach (Spinacia oleracea L.) was cultivated on soil treated with sewage sludge. The sewage sludge contained various trace elements (As, Cd, Cu, Zn), and the uptake of these trace elements placed the plant under stress. Following this, a sequential extraction procedure was employed to determine the levels and distributions of trace elements within the most important groups of compounds present in the spinach plants. Since the usual five-step sequential extraction procedure provides only general information on the distributions of elements within individual groups of organic compounds, due to the wide range of organic compounds within the individual fractions, this scheme was extended and improved through the addition of two solvent extraction steps-a butanol step (between the ethyl acetate and methanol solvent steps) and an H(2)O step (after the methanol+H(2)O solvent step). The distributions and levels of the trace elements within the main groups of compounds in spinach biomass was investigated using this new seven step sequential extraction (water free solvents: petroleum ether (A) --> ethyl acetate (B) --> butanol (C) --> methanol (D) --> water solvents: methanol+H(2)O (1+1; v/v) (E) --> H(2)O (F) --> methanol+H(2)O+HCl (49.3+49.3+1.4; v/v/v) (G)). The isolated fractions were characterized using IR spectroscopy and the trace element contents were determined in the individual fractions. Lipophilic compounds with low contents of Cd, Cu and Zn were separated in the first two fractions (A, B). Compounds with higher As contents (11.5-12.8% of total content) were also extracted in the second fraction, B. These two fractions formed the smallest portion of the isolated fractions. Low molecular compounds from secondary metabolism and polar lipids were separated in the third (C) and fourth (D) fractions, and high molecular compounds (mainly polypeptides and proteins) separated in the fifth and sixth fractions (E, F). The addition of the H(2)O solvent step was particularly useful for separating compounds that have a significant impact on trace element bounds. The methanol fraction was dominant for all treatments, and a significant decrease in the spinach biomass separated in this fraction was observed when the soil was treated with sewage sludge. Most of the As (35.5-38.8% of total content), Cu (45.0-51.6%) and Zn (39.8-47.2%) was also determined in this fraction. The G fraction (obtained after acid hydrolysis) contained polar compounds. Most of the Cd was also found in this fraction, as was a significant amount of Zn. Non-extractable residues formed the last fraction (polysaccharides, proteins).

Biomass↗
PubMed1991

Information needs of families of cancer patients: a literature review and recommendations.

This paper reviews evidence on the kinds of information needed by family members of cancer patients, discusses why families frequently lack needed information, and suggests strategies for meeting their information needs. Studies reviewed show that families' needs for information are substantial and that a large percentage of family members feel that these needs have not been adequately met by health care providers. This lack of needed information negatively affects the patient's care as well as the physical, psychological, and social well-being of family members. Strategies for addressing this problem include wider distribution of generic information about cancer and treatments to family members as well as developing standard professional procedures for making information about a patient's clinical condition available to family members.

Consumer Behavior↗
PubMed2005

Collective attacks and unconditional security in continuous variable quantum key distribution.

We present here an information theoretic study of Gaussian collective attacks on the continuous variable key distribution protocols based on Gaussian modulation of coherent states. These attacks, overlooked in previous security studies, give a finite advantage to the eavesdropper in the experimentally relevant lossy channel, but are not powerful enough to reduce the range of the reverse reconciliation protocols. Secret key rates are given for the ideal case where Bob performs optimal collective measurements, as well as for the realistic cases where he performs homodyne or heterodyne measurements. We also apply the generic security proof of Christiandl et al. to obtain unconditionally secure rates for these protocols.

Journal Article↗
PubMedDate not supplied

[Differences in income distribution data between the population census and household surveys (PNAD): conceptual and operational aspects].

"The [purpose] of this article is to explain the main differences between the concepts and the [collection procedures] of income distribution data used in [the] 1980 demographic census and in [the] 1979 and 1981 household surveys in Brazil. The article also comments [on] some differences about the data information on income distribution produced by census and household surveys." (SUMMARY IN ENG)

Americas↗
PubMed1985

Intratumor localization of monoclonal antibody in patients with melanoma treated with antibody to a 250,000-dalton melanoma-associated antigen.

Antibody localization at the tumor site was assessed in melanoma patients who received the murine monoclonal antibody 9.2.27. Antibody was administered twice weekly in escalating doses from 1 to 500 mg. Localization was assessed by biopsies of cutaneous and lymph node lesions obtained 24-96 hours following therapy. The percentage of tumor cells that bound the antibody in vivo was dose dependent, with similar findings obtained by either flow cytometry or immunoperoxidase staining techniques. Little or no in vivo binding of the 9.2.27 antibody to tumor cells was found following 1- and 10-mg doses, whereas all specimens demonstrated in vivo binding of the antibody following 200- and 500-mg doses. Fluorescence staining intensity, as quantitated by flow cytometry, was employed to determine the degree of in vivo saturation of antibody binding sites following therapy. The degree of saturation was found to vary substantially among patients: Some patients demonstrated nearly 100% saturation after 200-mg doses of 9.2.27 antibody, whereas others demonstrated only half maximal saturation after doses of 500 mg. Although immunoperoxidase staining provided important qualitative information regarding the distribution of antigen and antibody within the tumor, these studies demonstrated the usefulness of immunofluorescent flow cytometry for quantitative assessment of antibody localization in solid tumors and provided information necessary for the design of further trials of monoclonal antibodies and immunoconjugates.

Antibodies, Monoclonal↗
PubMed1991

A simulation study comparing designs for dose ranging.

Only with knowledge of the (prior) distribution of dose-response parameters in a population, can one determine both the initial dose of a drug for chronic administration to an individual (such as the dose producing a fixed degree of response in a fixed proportion of the population) and an appropriate subsequent (adjusted) dose (such as the dose yielding a desirable response according to the posterior parameter distribution, given an observed response to an initial dose). The currently FDA-sanctioned design for a dose-ranging study, the parallel-dose design, assigns just one of several doses to each patient. It does not provide good information on the distribution of individual dose-response parameters. A cross-over design assigns several dose levels to each patient. It therefore can provide better information, but does not resemble clinical practice. Consequently, study participants must be restricted to patients who can tolerate such non-therapeutic drug exposure, posing problems in extrapolation of study results to other types of patients. A titration or dose-escalation design begins all patients on placebo and, except for those patients assigned to a placebo-only group, escalates the dose for a patient at preset intervals only when clinical response at lower doses is inadequate. It both exposes patients to several dose levels and resembles good clinical practice, allowing study of a representative patient sample. We report here the simulation results of parameter estimation for the three designs when the data arise from complex and realistic dose-response models and/or with certain complications in study execution. The dose-escalation design clearly performs better overall than the parallel-dose design for the models considered here, and generally, just a little worse than the cross-over design. These results support the conclusion that for dose ranging, depending on the demands of the clinical situation, one should use either the cross-over or the dose-escalation design.

Algorithms↗
PubMed2006

MobileMed: a PDA-based mobile clinical information system.

Patient clinical data are distributed and often fragmented in heterogeneous systems, and therefore the need for information integration is a key to reliable patient care. Once the patient data are orderly integrated and readily available, the problems in accessing the distributed patient clinical data, the well-known difficulties of adopting a mobile health information system, are resolved. This paper proposes a mobile clinical information system (MobileMed), which integrates the distributed and fragmented patient data across heterogeneous sources and makes them accessible through mobile devices. The system consists of four main components: a smart interface, an HL7 message server (HMS), a central clinical database (CCDB), and a web server. The smart interface and the HMS work in concert to generate HL7 messages from the existing legacy systems, which essentially send the patient data in HL7 messages to the CCDB to be stored and maintained. The CCDB and the web server enable the physicians to access the integrated up-to-date patient data. By proposing the smart interface approach, we provide a means for effortless implementation and deployment of such systems. Through a performance study, we show that the HMS is reliable yet fast enough to be able to support efficient clinical data communication.

Computer Communication Networks↗
PubMed1990

Knowledge and attitudes of health care workers about AIDS and HIV infection before and after distribution of an educational booklet.

Hospital workers (509) in a health authority were surveyed, and asked if they were in contact with HIV positive or AIDS patients; about their perception of risk; of their knowledge about and attitudes towards HIV and AIDS problems at work; and their desire for more information about AIDS and HIV. Overall scores for level of knowledge and attitudes were calculated; clinical workers scored better than non-clinical workers. Following the first survey, an information booklet was distributed to all health authority staff and after distribution, 232 staff were surveyed again. In this group (the follow-up group), there was a reduction in perceived risk, an improvement in the level of knowledge and in attitudes, and a reduction in the desire for further information. The group who initially had the least level of knowledge and most unfavourable attitudes (non-clinical workers) were the group who improved most.

Acquired Immunodeficiency Syndrome↗
PubMed2006

Written medicines information for South African HIV/AIDS patients: does it enhance understanding of co-trimoxazole therapy?

Written information to promote patient education is being increasingly recognized as an integral part of quality health care. The main objective of this study was to evaluate the effect of distributing a patient information leaflet (PIL) on knowledge acquisition and recall. Two different PILs were designed for co-trimoxazole tablets: a simple, shorter PIL that incorporated pictograms and text and a text-only PIL that was longer and more complex. Human immunodeficiency virus-positive participants on chronic co-trimoxazole therapy were enrolled from five local primary health care clinics in Grahamstown, South Africa, and were randomly allocated to a Control Group (no PIL), Group A (text-only PIL) or Group B (simple PIL with pictograms). At the preliminary interview, demographic data were collected and the tablets dispensed according to normal clinic protocol. In a follow-up interview approximately 14 days later, participant medicines knowledge was investigated by asking a series of questions. The mean percentage for medicines knowledge was significantly higher in the group that received the simple PIL incorporating pictograms (76.3%), compared with both the Control Group (43.3%) and the group who received the longer, text-only PIL (50.9%). This study reinforces the value of providing patients with an appropriately designed PIL to inform appropriate medicine-taking behaviour.

Adolescent↗
PubMed2004

Utility of a three-dimensional cultured human skin model as a tool to evaluate the simultaneous diffusion and metabolism of ethyl nicotinate in skin.

The simultaneous diffusion and metabolism of ethyl nicotinate (EN) in a cultured human skin model, Living Skin Equivalent-high, was evaluated by the in vitro skin permeation and metabolism experiments, and esterase distribution was also determined. Theoretical calculations using Fick's 2nd Law of Diffusion with Michaelis-Menten kinetics were performed to obtain the permeation and metabolic parameters together with information on enzyme distribution. The obtained data was compared with the corresponding results in excised hairless rat skin. The partition coefficient of EN from the vehicle to the skin was of the same order of magnitude for the cultured human skin and hairless rat skin, but the diffusion and metabolic parameters were different. Esterase concentration in the epidermal membrane was greater than in the dermis of cultured skin, which was similar to hairless rat skin. Taking into account the similarities and differences between the membranes, the cultured human skin model can be utilized as a model membrane to rapidly predict simultaneous diffusion and metabolism of the prodrug through human skin.

Algorithms↗
PubMed2001

Monte Carlo MCNP-4B-based absorbed dose distribution estimates for patient-specific dosimetry.

UNLABELLED: This study was intended to verify the capability of the Monte Carlo MCNP-4B code to evaluate spatial dose distribution based on information gathered from CT or SPECT. METHODS: A new three-dimensional (3D) dose calculation approach for internal emitter use in radioimmunotherapy (RIT) was developed using the Monte Carlo MCNP-4B code as the photon and electron transport engine. It was shown that the MCNP-4B computer code can be used with voxel-based anatomic and physiologic data to provide 3D dose distributions. RESULTS: This study showed that the MCNP-4B code can be used to develop a treatment planning system that will provide such information in a time manner, if dose reporting is suitably optimized. If each organ is divided into small regions where the average energy deposition is calculated with a typical volume of 0.4 cm(3), regional dose distributions can be provided with reasonable central processing unit times (on the order of 12-24 h on a 200-MHz personal computer or modest workstation). Further efforts to provide semiautomated region identification (segmentation) and improvement of marrow dose calculations are needed to supply a complete system for RIT. It is envisioned that all such efforts will continue to develop and that internal dose calculations may soon be brought to a similar level of accuracy, detail, and robustness as is commonly expected in external dose treatment planning. CONCLUSION: For this study we developed a code with a user-friendly interface that works on several nuclear medicine imaging platforms and provides timely patient-specific dose information to the physician and medical physicist. Future therapy with internal emitters should use a 3D dose calculation approach, which represents a significant advance over dose information provided by the standard geometric phantoms used for more than 20 y (which permit reporting of only average organ doses for certain standardized individuals)

Adult↗
PubMed1989

Study designs for dose-ranging.

Premarketing dose-ranging studies of a drug are done to establish a reasonable initial dose. According to the current procedure sanctioned by the Food and Drug Administration, each patient is given one of several possible doses, including placebo, after an initial placebo run-in period. Data analysis is based on a model in which the mean response at each dose is independent of the magnitude of the dose. The initial dose is the lowest dose tested that has a response that is statistically significantly greater than the response after placebo administration. We suggest that the present conceptual approach to, and standard study design and analysis for, dose-ranging studies be changed. We believe one must begin with a parametric model for patient-specific dose-response curves. Knowledge of the distribution of these curves in a population provides a basis for choice of an initial dose (e.g., the dose that achieves a given response in a given fraction of patients) and, after observation of response to an initial dose, for choice of an incremental dose for a specific patient (by use of Bayes rule). The current parallel-dose design can provide only poor information about the distribution of dose-response curves, biased estimates of the typical curve, and little information on interpatient variability. Crossover studies provide better information. In studies in which a parametric patient-specific dose-response model is used, a dose-escalation design provides no less information than a crossover design, and it has ethical advantages that allow a more representative patient group and clinical setting to be studied.

Analysis of Variance↗
PubMed1982

How to measure first-order hepatic transfer coefficients by distributed modeling of a recirculating rat liver perfusion system.

A digital computer is used to simulate solute disappearance curves evolving in the reservoir of a rat liver perfusion system. The results show that it is feasible to obtain good estimates of these kinetic parameters with only approximate information about the distribution of sinusoidal flows and the transfer function of the nonexchanging vasculature. By contrast satisfactory estimates of the transfer coefficients for uptake and efflux (but not excretion) are critically dependent on accurate measurements of the system transit times. A perfusion system suitable for implementing the method is tested and found to maintain normal liver function for upward of 60 min. The means to achieve the required volume and flow measurements are discussed, and an empirical criterion is developed for recognizing disappearance curves whose information content is too low to yield reliable results.

Animals↗
PubMed2006

Microstructural modeling of collagen network mechanics and interactions with the proteoglycan gel in articular cartilage.

Cartilage matrix mechanical function is largely determined by interactions between the collagen fibrillar network and the proteoglycan gel. Although the molecular physics of these matrix constituents have been characterized and modern imaging methods are capable of localized measurement of molecular densities and orientation distributions, theoretical tools for using this information for prediction of cartilage mechanical behavior are lacking. We introduce a means to model collagen network contributions to cartilage mechanics based upon accessible microstructural information (fibril density and orientation distributions) and which self-consistently follows changes in microstructural geometry with matrix deformations. The interplay between the molecular physics of the collagen network and the proteoglycan gel is scaled up to determine matrix material properties, with features such as collagen fibril pre-stress in free-swelling cartilage emerging naturally and without introduction of ad hoc parameters. Methods are developed for theoretical treatment of the collagen network as a continuum-like distribution of fibrils, such that mechanical analysis of the network may be simplified by consideration of the spherical harmonic components of functions of the fibril orientation, strain, and stress distributions. Expressions for the collagen network contributions to matrix stress and stiffness tensors are derived, illustrating that only spherical harmonic components of orders 0 and 2 contribute to the stress, while orders 0, 2, and 4 contribute to the stiffness. Depth- and compression-dependent equilibrium mechanical properties of cartilage matrix are modeled, and advantages of the approach are illustrated by exploration of orientation and strain distributions of collagen fibrils in compressed cartilage. Results highlight collagen-proteoglycan interactions, especially for very small physiological strains where experimental data are relatively sparse. These methods for determining matrix mechanical properties from measurable quantities at the microscale (composition, structure, and molecular physics) may be useful for investigating cartilage structure-function relationships relevant to load-bearing, injury, and repair.

Biomechanical Phenomena↗