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This article describes an adaptation of the Neuman Systems Model to the care of the hospitalized preschool child. This was done to unite the physical care of the hospitalized preschool child with other aspects of his development and to describe the causes and prevention of stresses of hospitalization for this child.
Using a highly infiltrative tumor type as basal cell carcinoma as the model system, we have examined the relation between invasive behavior and proliferation. Our results studying alterations in G(1)-S cell cycle regulatory proteins and proliferation in infiltrative cells were surprising and clearly indicated that invasion in tumors with an intact p16(INK4a)-cyclin D-retinoblastoma protein (Rb) pathway was equivalent to ceased proliferation. Using immunohistochemistry and Western blotting of microdissected parts of basal cell carcinomas, we showed that p16(INK4a) was up-regulated at the invasive front of the majority of basal cell carcinomas with infiltrative growth patterns, followed by ceased proliferation, as well as decreased phosphorylation of Rb. Besides supporting the fact that basal cell carcinomas have an intact Rb pathway, our results clearly indicate that invasive tumor cells change phenotype from a proliferative state to an invasive phenotype. Thus, invasion is not necessarily analogous with proliferation, implicating a paradigm shift in the understanding of two central processes in malignant behavior.
The purpose of this report is to describe the use of the Corneal Modeling System (CMS) in the quantitative evaluation of the front surface of a soft contact lens on a keratoconic cornea. The management of one eye of a single case is presented as an example. A keratoconic patient fitted with an RGP lens presented with the signs and symptoms of discomfort, reduced wearing time and recurrent corneal erosions. Corneal topography was evaluated utilizing the CMS. The patient was then fitted with a soft contact lens. Next the entire front surface of the contact lens-fitted eye was measured with the CMS. Utilizing those data a piggyback lens was designed. As a result of this fitting technique corneal integrity improved, wearability increased and discomfort dissipated.
This paper explores the selection and application of the Betty Neuman Systems Model for the fourth and final year of a generic baccalaureate programme of nursing. Its articulation with content and process, the teaching strategies and learning outcomes for both students and faculty are discussed.
Three major methods have been described for the isolation of fetal cells from maternal blood: fluorescence-activated cell sorting (FACS), immunomagnetic beads, and magnetic-activated cell sorting (MACS). To date, no study has directly compared fetal cell recovery using each of these methods. Here we describe our system using a "model' male fetal cell mixed into female peripheral blood mononuclear cells. Fetal cell yields and purities were assayed by a quantitative polymerase chain reaction (qPCR) using chromosomes Y- and 7-specific sequences. Fetal cell recovery was investigated by selection of CD71+ cells or depletion of CD45+ cells. Our data demonstrated variation in fetal cell recovery for all methods tested, although CD71+ selection by FACS gave the best and most consistent results.
Physiological levels of a purified T cell hormone, interleukin 2 (IL-2), were found to stimulate a cloned murine B cell line (BCL1) to secrete pentamer IgM antibody. The peptide hormone acts at the cell surface via specific IL-2 receptors and induces changes in the 5' chromatin of the J chain gene that correlate with its transcription and with the production of the J chain protein required for pentamer IgM assembly. There was no effect of IL-2 on cell proliferation nor on mu heavy chain gene transcription. These results define a specific function for IL-2 in B cell differentiation. In addition, the IL-2/BCL1 system provides a model for examining the mechanism by which signals generated by hormone-receptor interaction are transmitted to the nucleus and regulate gene expression.
Light and electron microscopy have been used to evaluate the effects of treating mouse cochlear cultures with the ototoxic aminoglycoside antibiotic neomycin sulphate at concentrations of 0.2 mM and greater for periods of up to 1 hour. Neomycin rapidly induces the formation of numerous, membrane filled blisters on the apical surfaces of the sensory hair cells. Such morphological damage is restricted to the hair cells, and is not observed on the surfaces of supporting cells within the organ of Corti. Hair cells in apical-coil cultures are less sensitive than those in basal-coil cultures, and, at any given point along the cochlea, outer hair cells appear to be more extensively damaged by neomycin than inner hair cells. These morphological effects of neomycin are considerably more severe when the drug is applied in calcium/magnesium free saline, and can be blocked by elevating the saline concentration of either calcium or magnesium. The effects can also be blocked by lowering the temperature to 4 degrees C, but not by either K+ depolarization or the lectin Concanavalin A. The potential value of this culture system as a model for studying aminoglycoside induced ototoxicity is discussed.
Human DNA can be damaged by natural metabolism through free radical production. It has been suggested that the equilibrium between innate damage and cellular DNA repair results in an oxidative DNA damage background that potentially contributes to disease and aging. Efforts to quantitatively characterize the human oxidative DNA damage background level, based on measuring 8-oxoguanine lesions as a biomarker, have led to estimates that vary over three to four orders of magnitude, depending on the method of measurement. We applied a previously developed and validated quantitative pathway model of human DNA base excision repair, integrating experimentally determined endogenous damage rates and model parameters from multiple sources. Our estimates of at most 100 8-oxoguanine lesions per cell are consistent with the low end of data from biochemical and cell biology experiments, a result robust to model limitations and parameter variation. Our findings show the power of quantitative system modeling to interpret composite experimental data and make biologically and physiologically relevant predictions for complex human DNA repair pathway mechanisms and capacity.
The dynamic changes in thiosulfinate profiles were studied in reaction systems containing a crude onion alliinase, S-alk(en)yl-L-cysteine sulfoxide substrates (1) and preformed thiosulfinates (4). Regioisomeric excesses of one of two possible heterologous 4 species (RS(O)SR', where R does not equal R') could be manipulated under conditions where alliinase, 1, and 4 levels were varied. Regioisomeric excesses could be explained by a thiosulfinate (4)/alkanesulfenic acid (2) trapping mechanism, with the greatest control over product profile governed by the rate of 2 generation in the system. The series of reactions existing in this dynamic reaction system was kinetically modeled with reasonable fits to the experimental data. The application of the 4/2 trapping strategy to manipulate thiosulfinate and related organosulfur product profiles in diluted onion homogenates was demonstrated using exogenous MeS(O)SMe (4a), PrS(O)SPr (4c), and AllS(O)SAll (4d) as the preformed thiosulfinate.
The bacteria Escherichia coli has been widely employed in studies of eukaryotic DNA repair genes. Several eukaryotic genes have been cloned by functional complementation of mutant lineages of E. coli. We examined the similarities and differences among bacterial and eukaryotic DNA repair systems. Based on these data, we examined tools used for gene cloning and functional studies of DNA repair in eukaryotes, using this bacterial system as a model.
Therapeutic effects of cyclophosphamide (CPA) were compared in L-W rats with (a) transplanted prostate adenocarcinomas (PAs), and (b) with induced autochthonous PAs. All rats, except controls, were treated by IP-administered CPA in slow-release silastic membranes (a) at time 0 after inoculation of transplanted PA cells; or (b) after development of palpable transplanted PAs thereof; or (c) after detection of palpable autochthonous PAs. The treated rats did not manifest evidence of CPA-related toxicity. The transplanted PAs and lung metastases thereof were suppressed by CPA; but, the same treatment schedule with CPA failed to modify continued growth of the autochthonous PAs. This report serves to emphasize the need for test systems of autochthonous model tumors of the counterpart disease in humans.
Especially in the area of public health organisations are many questions about the medical valuation of environmental pollutions. Now the complicated coherences between environment and health contains great problems on scientific investigations. With the aid of an ecological model of environmental systems it is possible to estimate effects of anthropogene pollutions. The aim is the development of a sufficient health protection program.
In recent years, the realization of a need for increased integration of acute care and long-term care (LTC) systems has grown. For the most part, however, a person requiring both types of care is treated as though he or she is two discrete individuals with separate needs. Organizations that have the integration of acute and LTC as a goal serve relatively small numbers of people. Integration efforts could be facilitated through the identification and application of an organizational systems model. Hospice can provide such a model. The hospice interdisciplinary team integrates not only multiple disciplines but also acute care and LTC. The hospice model is also appropriate from a financial standpoint in that Medicare hospice funding has employed a prospective payment system (PPS) since the inception of the Medicare Hospice Benefit. In this article, the application of the hospice model to the integration of the acute care and LTC systems in the U.S. is demonstrated, using a subsystem approach.
Saccharomyces cerevisiae served as a model fungal system to examine functional genomics of oxidative stress responses and reactions to test antioxidant compounds. Twenty-two strains of S. cerevisiae, including a broad spectrum of singular gene deletion mutants, were exposed to hydrogen peroxide (H2O2) to examine phenotypic response to oxidative stress. Responses of particular mutants treated with gallic, tannic or caffeic acids, or methyl gallate, during H2O2 exposure, indicated that these compounds alleviated oxidative stress. These compounds are also potent inhibitors of aflatoxin biosynthesis in Aspergillus flavus. To gain further insights into a potential link between oxidative stress and aflatoxin biosynthesis, 43 orthologs of S. cerevisiae genes involved in gene regulation, signal transduction (e.g., SHO1, HOG1, etc.) and antioxidation (e.g., CTT1, CTA1, etc.) were identified in an A. flavus expressed sequence tag library. A successful exemplary functional complementation of an antioxidative stress gene from A. flavus, mitochondrial superoxide dismutase (sodA), in a sod2Delta yeast mutant further supported the potential of S. cerevisiae deletion mutants to serve as a model system to study A. flavus. Use of this system to further examine functional genomics of oxidative stress in aflatoxigenesis and reduction of aflatoxin biosynthesis by antioxidants is discussed.
Patterns of excision of a single P element were studied in a model system of the yellow locus. The data obtained were in good agreement with the generally accepted SDSA (synthesis-dependent strand annealing) model. Specific features of P element excision in the presence of two tandemly repeated copies are presented. The pattern of P element excision depended on the sequences surrounding the insertion site and on the number of its additional copies present in the genome.
The potential of the vertebrate limb as a model system to study developmental mechanisms is particularly well illustrated by the analysis of the Hox gene network. These genes are probably involved in the establishment of patterns encoding positional information. Their functional organisation during both limb and trunk development are very similar and seem to involve the progressive activation in time, along the chromosome, of a battery of genes whose products could differentially instruct those cells where they are expressed. This process may be common to all organisms that develop according to an anterior-posterior morphogenetic progression. The possible linkage of this system to a particular mechanism of segmentation as well as its phylogenetic implications are discussed.
To understand the physiological effects of substances used in drugs and therapies on heart muscle tissue, model systems that mirror the in vivo situation of living tissues are required. Therefore, the creation of 3-dimensional (3D) cell aggregates provides an improved and refined in vitro model as a link between cell-free or single cells and organs or whole organisms in vivo. Here we have characterized a stable contracting in vitro tissue model, which consists of embryonic chicken cardiomyocytes. For establishing a cell-based test system, the 3D in vitro cardiomyocyte spheres were characterized according to messenger RNA expression of special cardiac cell types and protein expression pattern of functional markers such as connexin-43. Finally, the in vitro spheroid model was used for investigating the effect of isoproterenol, a *-adrenergic receptor agonist, on the contractibility mediated by the ligand receptor interaction.
Previous research has demonstrated dissociations between categorization and recognition performance in amnesic patients, supporting the idea that separate memory systems govern these tasks. However, previous research has also demonstrated that these dissociations are predicted by a single-system model that allows for reasonable parameter differences across groups. Generally, previous studies have employed categorization tasks that are less demanding than the recognition tasks. In this study, we distinguish between single-system and multiple-system accounts by testing memory-impaired individuals in a more demanding categorization task. These patients, just like previous amnesic participants, show a dissociation between categorization and recognition when tested in previously employed paradigms. However, they display a categorization deficit when tested in the more challenging categorization task. The results are interpreted as support for a single-system framework in which categorization and recognition depend on one representational system.