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At least 595 records · Page 33Linked to original sources
PubMed1977

Development aid through information. Trying a new concept in Columbia.

The origin, execution, and preliminary results of a development project in Cali (Colombia) are presented. This project, which involves a special concept, aims at breaking new ground in the field of development aid. The aim of the Vivamos Mejor foundation, established in Colombia, is to provide practical help for poor families. The foundation is carrying out two model projects at the moment, which provide urgently required help and which at the same time investigate the feasibility and effectiveness of the projects in a scientific manner. Under the first project, teams of native inhabitants provide information and instruct the population thoroughly on questions of nutrition, hygiene, and birth control. Under the second project, children who are suffering from disease and malnutrition are temporarily rehabilitated in crèches, while at the same time their mothers learn how to provide the child and its brothers and sisters with a more healthy home. On one hand the Swiss projects in Cali aim at helping families in the poor areas there, while on the other, they are being scientifically analyzed as model projects in the hope that they can provide examples for the large cities in other developing countries.

Adolescent↗
PubMed1980

Depression: the tip of the iceberg.

A number of potential obstacles to objective diagnosis have been described, somatic presentations of 'masked depression' being only one of these. The morbidity associated with untreated depressive illness, availability of effective treatment resources, and gradually increasing community expectations, have all contributed to an increased responsibility on the medical practitioner for accurate diagnosis. It is evident that not only intellectual diagnostic acumen but an attitude of tolerance and acceptance of pathological emotional states is fundamental in facilitating self-disclosure leading to accurate diagnosis, and is a foundation for effective treatment. A model of depressive illness which includes biological, psychological and social aspects is appropriate, and can greatly augment mastery of these problems in practice.

Adult↗
PubMed1983

Three dimensional growth of the mouse isocortex.

The three dimensional growth of the mouse isocortex was examined by plotting the variations in intermediate layer depth on orthogonal projections of the telencephalic surface at successive periods of development; a histological status was assigned to each depth. Thus portrayed, the development of the isocortex was seen as a propagated sequence of histological change, commencing at a rostral focus coextensive with the caudatopallial angle and thence spreading across the telencephalic wall. Growth was asymmetric about the focus of origin and terminated in a rostrocaudal direction as the spread of neuron production reached and extinguished a growth zone along the sagittal perimeter of the hemisphere. The possibility of mouse isocortical histogenesis representing a variation of a general mammalian pattern was noted, as was the evolutionary and methodological significance of the apparent coincidence of the origin of the gradient of isocortical neuron release with the region of cortex representing oropharyngeal structures. An alternative form of representation of the isocortical gradient, as the summation of a number of radial strips of tissue each with a similar history of neuron release and migration, was used to lay a foundation for a three dimensional model.

Animals↗
PubMed1977

[Rational bases for cooperation between epidemiologists and mathematicians].

The authors consider rational foundations underlying creatin of realistic models. The principal condition for the successful mathematical modelling is obtaining of the most full value primary materials on the course of the epidemic process. For this purpose the authors suggest definite principles of the methodical approach to the mathematical modelling. Possibilities of the use of mathematical methods for various groups of infections are consideder. Particular attention is paid to the works on the study of the infection risk in "small" collective bodies.

Communicable Diseases↗
PubMed1998

Imaging of adenoviral-directed herpes simplex virus type 1 thymidine kinase reporter gene expression in mice with radiolabeled ganciclovir.

UNLABELLED: We are developing procedures to repeatedly and noninvasively image the expression of transplanted reporter genes in living animals and in patients, using PET. We have investigated the use of the Herpes Simplex Virus type 1 thymidine kinase gene (HSV1-tk) as a reporter gene and [8-14C]-ganciclovir as a reporter probe. HSV1-tk, when expressed, leads to phosphorylation of [8-14C]-ganciclovir. As a result, specific accumulation of phosphorylated [8-14C]-ganciclovir should occur almost exclusively in tissues expressing the HSV1-tk gene. METHODS: An adenoviral vector was constructed carrying the HSV1-tk gene along with a control vector. C6 rat glioma cells were infected with either viral vector and uptake of [8-3H]-ganciclovir was determined. In addition, 12 mice were injected with varying levels of either viral vector. Adenovirus administration in mice leads primarily to liver infection. Forty-eight hours later the mice were injected with [8-14C]-ganciclovir, and 1 hr later the mice were sacrificed and biodistribution studies performed. Digital whole-body autoradiography also was performed on separate animals. HSV1-tk expression was assayed, using both normalized HSV1-tk mRNA levels and relative HSV1-TK enzyme levels, in both the cell culture and murine studies. RESULTS: Cell culture, murine tissue biodistribution and murine in vivo digital whole-body autoradiography all demonstrate the feasibility of HSV1-tk as a reporter gene and [8-14C]-ganciclovir as an imaging reporter probe. A good correlation (r2 = 0.86) between the [8-14C]-ganciclovir percent injected dose per gram tissue from HSV1-tk positive tissues and HSV1-TK enzyme levels in vivo was found. An initial study in mice with [8-18F]-fluoroganciclovir and microPET imaging supports further investigation of [8-18F]-fluoroganciclovir as a PET reporter probe for imaging HSV1-tk gene expression. CONCLUSION: These results demonstrate the feasibility of using [8-14C]-ganciclovir as a reporter probe for the HSV1-tk reporter gene, using an in vivo adenoviral mediated gene delivery system in a murine model. The results form the foundation for further investigation of [8-18F]-fluoroganciclovir for noninvasive and repeated imaging of gene expression with PET.

Adenoviridae↗
PubMed2004

On the effects of residual stress in microindentation tests of soft tissue structures.

Microindentation methods are commonly used to determine material properties of soft tissues at the cell or even sub-cellular level. In determining properties from force-displacement (FD) data, it is often assumed that the tissue is initially a stress-free, homogeneous, linear elastic half-space. Residual stress, however, can strongly influence such results. In this paper, we present a new microindentation method for determining both elastic properties and residual stress in soft tissues that, to a first approximation, can be regarded as a pre-stressed layer embedded in or adhered to an underlying relatively soft, elastic foundation. The effects of residual stress are shown using two linear elastic models that approximate specific biological structures. The first model is an axially loaded beam on a relatively soft, elastic foundation (i.e., stress-fiber embedded in cytoplasm), while the second is a radially loaded plate on a foundation (e.g., cell membrane or epithelium). To illustrate our method, we use a nonlinear finite element (FE) model and experimental FD and surface contour data to find elastic properties and residual stress in the early embryonic chick heart, which, in the region near the indenter tip, is approximated as an isotropic circular plate under tension on a foundation. It is shown that the deformation of the surface in a microindentation test can be used along with FD data to estimate material properties, as well as residual stress, in soft tissue structures that can be regarded as a plate under tension on an elastic foundation. This method may not be as useful, however, for structures that behave as a beam on a foundation.

Animals↗
PubMed2003

The optical properties of the crystalline lens and their significance.

We do not yet have definitive data on the optical structure of the lens, including surface shapes and gradient refractive index distribution. Some data do exist but we need much more data to complete our knowledge of this structure. However, using current and sparse knowledge, we can use mathematical modelling to study the effects of surface shapes and gradient refractive index structure on the Gaussian and aberration properties of the lens. The equations extracted from this modelling show some interesting results, for example, the way the gradient index structure provides some of the refractive power and how this structure possibly predicts a negative spherical aberration of the lens, which is observed in real eyes. This modelling will provide a firm theoretical foundation for analysing more accurate and extensive lenticular shape and refractive index data as they become available.

Humans↗
PubMed2002

The Minnesota Health Partnership and Coordinated Health Care and Disability Prevention: the implementation of an integrated benefits and medical care model.

In the spring of 1996, the Minnesota Health Partnership (MHP) received a demonstration grant from the Robert Wood Johnson Foundation Workers Compensation Health Initiative to pilot a model of health care that was designed to combine the best practices of general health and workers' compensation medical care. This paper outlines the genesis of the MHP, and the relationship of its Coordinated Health Care and Disability Prevention model to traditional managed care and 24-h care models. In order to effectively implement disability prevention principles within a primary care clinical setting, it is essential to increase health care provider awareness that the disability relating to a specific impairment can be positively impacted by specific clinical strategies. The basis and specifics of these strategies are also discussed. Plans for the evaluation of this model will also be described.

Employment, Supported↗
PubMed2001

Strides in care management: the development of a framework to facilitate quality outcomes.

Care Management has been in existence for years. The thrust of the role is to monitor, evaluate and enhance resource utilization while maintaining quality of care. The pivotal assumption being through enhanced patient flow, and coordinated services with appropriate resource utilization, better patient outcomes are achieved. During times of fiscal restraint, quality may become a secondary concern. This paper presents a framework to assist Care Managers, and administrators, in achieving desired outcomes that embrace fiscal accountability and quality patient care. Donabedian's model and Systems theory are the foundations for this framework.

Canada↗
PubMed2006

Interdisciplinary model for palliative care in the trauma and surgical intensive care unit: Robert Wood Johnson Foundation Demonstration Project for Improving Palliative Care in the Intensive Care Unit.

Integrating palliative care into the surgical and trauma intensive care unit is challenging. The nature of surgical illness, practice patterns of surgeons and critical care nurses, and the culture of the intensive care unit all suggest that familiar models of palliative care do not apply in this setting. We describe a novel interdisciplinary model of palliative care in the surgical intensive care unit, which addresses communication, shared decision making, and pain and symptom management for all critically ill patients, regardless of prognosis. This communication-based model integrates new processes of care into existing surgical critical care practice so that palliative care can be provided in parallel with surgical care.

Decision Making↗
PubMed2004

Rheology and microscopic topology of entangled polymeric liquids.

The viscoelastic properties of high molecular weight polymeric liquids are dominated by topological constraints on a molecular scale. In a manner similar to that of entangled ropes, polymer chains can slide past but not through each other. Tube models of polymer dynamics and rheology are based on the idea that entanglements confine a chain to small fluctuations around a primitive path that follows the coarse-grained chain contour. Here we provide a microscopic foundation for these highly successful phenomenological models. We analyze the topological state of polymeric liquids in terms of primitive paths and obtain parameter-free, quantitative predictions for the plateau modulus, which agree with experiment for all major classes of synthetic polymers.

Journal Article↗
PubMed1997

Relationship between size of denture foundation area and resorption of alveolar ridge in the edentulous mandible.

The relationship between the size of the denture foundation area and the resorption of the alveolar ridge was investigated in 55 edentulous subjects. The denture foundation area was recorded using a modelling compound impression technique with border moulding. Both sides of each edentulous mandible were examined separately, making a total of 110 experimental sides in the study. On a stone cast made from each impression, the size of of the superficial denture foundation area and of the projected denture foundation area on the tentative plane of occlusion of each anatomical zone were measured. The vertical height of the alveolar ridge at the lateral incisor and first molar region was also evaluated. The size of the superficial denture foundation area in the antero-lingual and postero-lingual zones showed no significant correlation with the degree of alveolar ridge resorption. The size of the projected denture foundation area on the tentative plane of occlusion in the anterior section showed negative significant correlation with the degree of alveolar ridge resorption. The size of the projected denture foundation area on the tentative plane of occlusion in the posterior section showed no significant correlation with the degree of alveolar ridge resorption.

Aged↗
PubMed1992

Application of the finite-element method to simulation of damage to the human skull as a consequence of missile impact on a multi-layered composite crash helmet.

Finite-element analysis is a powerful technique which could be applicable to the study of a wide range of circumstances where the frame and/or the vital organs of the body are subjected to extreme loading conditions. This paper reports the results of an exploratory investigation in which the performance of a crash helmet in protecting the skull from an impacting load is modelled. The immediate objective is to show how a typical crash helmet design of glass-reinforced plastic (GRP) outer casing with quasi-foam-like liner can, with a suitable choice of material properties, attenuate the transfer of energy from the impacting mass such that the damage intensity to the skull is minimized. A simplified structure for both helmet and skull shape is adopted and the skull is modelled as being supported on an elastic foundation. The material properties used are representative rather than being accurately matched to experimentally determined ones. Several aspects of the modelling technique are worthy of particular note: the simulation of material anisotropy by means of multiple reinforcement layers with varying orientation, the use of dashpot elements for energy attenuation and the incorporation of multipoint constraint between the skull and the helmet lining to ensure integrity of the model with correct stiffness matrix values and allowing independent monitoring of all stress levels at the mating interface region. The results of the modelling show that the specific limited objectives can be met but also indicate how vitally important information could be obtained from similar but more detailed studies which included representative modelling of the body organs and skeleton.

Anisotropy↗
PubMed1992

Radial keratotomy. III. Relationship between wound gape and corneal curvature in primate eyes.

The relationship between changes in wound gape and corneal curvature after radial keratotomy (RK) was evaluated in five primates. Four-incision RK was performed using a diamond knife set to 100% of central corneal thickness with a 3-mm optical zone. In vivo measurements of wound gape were obtained using tandem scanning confocal microscopy at 3, 7, 14, and 45 days after surgery. The changes in corneal contour were measured at the same time points using a corneal modeling system with a specially designed primate cone. Wounds progressively increased in width to a maximum of 38 +/- 1 microns (n = 5) at day 7. After day 7, wounds showed increasing fibrosis which correlated with decreasing wound gape to 20 +/- 1 microns at day 45. A similar temporal change was detected in central corneal curvature (K), with maximum flattening occurring at day 7 (delta K = -3.17 +/- 0.90 diopters, n = 5), and progressive regression of effect to -1.32 +/- 0.61 diopters (n = 5) at day 45. Although there was interanimal variation, the mean temporal changes in corneal curvature significantly paralleled the changes in wound gape (r = -0.96, n = 4, P < 0.05). Based upon these findings, a simple geometric model was proposed which provides a hypothetic foundation for the relationship between corneal curvature and wound gape after RK. Calculations of wound gape made from this analytic model (using the measured topographic data) showed significant correlation with the actual wound gape measurements (r = 0.96, n = 4, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1998

Genetic immunization against neu/erbB2 transgenic breast cancer.

erbB2/neu, an overexpressed oncogene product, has been proposed as a human cancer vaccine target. In the present study, transgenic (rat neuNT oncogene) FVB/neu mice, developing metastasizable mammary carcinoma, were immunized with a plasmid DNA encoding are not tolerant to the self antigen and sequences. We report that transgenic tumour-bearing mice, like some breast cancer patients erbB2 + X, develop anti-neu autoimmune responses, which can be boosted and skewed to a Th1 phenotype by DNA immunization. Intramuscular injections of neuNT plasmid drastically reduced (or even prevented in a small number of treated mice) the outgrowth of mammary neoplasms as well as their metastatic penetrance. Furthermore, DNA immunization caused haemorrhagic necrosis of established cancer nests, leaving a greatly reduced portion of the tumour burden for the host to cope with. The antitumour activities we obtained, in this very challenging model for cancer immunotherapy, lay the foundation for DNA-based immunization to control erbB2/neu-overexpressing neoplasms.

Adenocarcinoma↗
PubMed2005

A cartilage growth mixture model for infinitesimal strains: solutions of boundary-value problems related to in vitro growth experiments.

A cartilage growth mixture (CGM) model is linearized for infinitesimal elastic and growth strains. Parametric studies for equilibrium and nonequilibrium boundary-value problems representing the in vitro growth of cylindrical cartilage constructs are solved. The results show that the CGM model is capable of describing the main biomechanical features of cartilage growth. The solutions to the equilibrium problems reveal that tissue composition, constituent pre-stresses, and geometry depend on collagen remodeling activity, growth symmetry, and differential growth. Also, nonhomogeneous growth leads to nonhomogeneous tissue composition and constituent pre-stresses. The solution to the nonequilibrium problem reveals that the tissue is nearly in equilibrium at all time points. The results suggest that the CGM model may be used in the design of tissue engineered cartilage constructs for the repair of cartilage defects; for example, to predict how dynamic mechanical loading affects the development of nonuniform properties during in vitro growth. Furthermore, the results lay the foundation for future analyses with nonlinear models that are needed to develop realistic models of cartilage growth.

Biomechanical Phenomena↗