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At least 253 records · Page 14Linked to original sources
PubMed2000

Identification of global data and partitioning scheme for modeling biological data within the electronic medical record.

Using "Black Box" theory we analyzed human physiology. The major physiological means of communication are the vascular and nervous systems. The fundamental partitions of physiology are the vascular capillary fields and efferent and afferent fields of the nervous system. These fields are generally associated with organs and organ systems. Such analysis leads to the conclusion that the global biological data are information carried within the vascular and nervous systems. Data elements and processes within organs are important to other organs only through their effects on these global elements. Incorporation of these concepts into medical databases would allow the partitioning of the software around physiological systems. As a result of partitioning the utility of the electronic medical record, software could be greatly expanded.

Humans↗
PubMed1981

On the nature of technetium compounds. 1. A semiquantitative biological model system to assay 99mTc-complexes/radiopharmaceuticals.

Eleven different 99mTc compounds having some relevance in clinical nuclear medicine have been classified according to their localizing properties. The following classes of 99mTc compounds have been compared in a semiquantitative manner, using a Wistar strain rat model: liver and hepatobiliary agents such as Tc-phytate, Tc-sulfur colloid, reduced (SnII) TcO-4, and 99mTc-LIDA (dimethyl-IDA); bone agents like Tc-pyrophosphate, Tc-HEDP, Tc-EDTMP; kidney and bladder agents comprising Tc-DTPA, Tc-glucoheptonate, Tc-citrate, and TcO-4. The in vivo pharmacokinetic behavior lends itself to unified approach with respect to nature of 99mTc compounds. Most of the 99mTc complexes display an excretory type of pathway. These compounds were found to be relatively stable in aqueous solutions at room temperature (25 degrees-28 degrees C) for at least 2 h without any additives. Both paper chromatographic and biologic (tissue distribution) criteria, commonly used for quality assurance and control of 99mTc compounds, were employed to study these compounds.

Animals↗
PubMed2003

Black rice (Oryza sativa L. indica) pigmented fraction suppresses both reactive oxygen species and nitric oxide in chemical and biological model systems.

Anthocyanins, present in fruits and vegetables as natural colorants, have been well characterized to possess bioactive properties. Anthocyanin components extracted from black rice (Oryza sativa L. indica) separated by gel filtration and identified using LC-MS were cyanidin 3-glucoside and peonidin 3-glucoside. A standardized extract of black rice pigmented fraction (BRE) containing known proportions of cyanidin 3-glucoside and peonidin 3-glucoside exhibited marked antioxidant activities and free radical scavenging capacities in a battery of in vitro model systems. Significant (p < 0.05) prevention of supercoiled DNA strand scission induced by reactive oxygen species (specifically, peroxyl radical and hydroxyl radicals) and suppression of the oxidative modification of human low-density lipoprotein was obtained with BRE. In addition, BRE reduced (p < 0.05) the formation of nitric oxide by suppressing inducible nitric oxide synthase expression in murine macrophage RAW264.7 cells, without introducing cell toxicity. The results of this study show that black rice contains anthocyanin pigments with notable antioxidant and anti-inflammatory properties for potential use in nutraceutical or functional food formulations.

Anthocyanins↗
PubMedDate not supplied

Modelling biological evolvability: implicit context and variation filtering in enzyme genetic programming.

This paper describes recent insights into the role of implicit context within the representations of evolving artefacts and specifically within the program representation used by enzyme genetic programming. Implicit context occurs within self-organising systems where a component's connectivity is both determined implicitly by its own definition and is specified in terms of the behavioural context of other components. This paper argues that implicit context is an important source of evolvability and presents experimental evidence that supports this assertion. In particular, it introduces the notion of variation filtering, suggesting that the use of implicit context within representations leads to meaningful variation filtering whereby inappropriate change is ignored and meaningful change is encouraged during evolution.

Algorithms↗
PubMed1997

Lewis lung carcinoma and two transplantable sarcomas in mice as experimental therapy models: biological characteristics and cell population kinetics.

The biological characteristics of three transplantable tumours: two sarcomas (SaL, MCA) and Lewis lung carcinoma (LLC) have been studied. We investigated histology, DNA ploidy and cell kinetics parameters of the tumours. All examined tumours were aneuploid and rapidly proliferating, with the hyperdiploid fraction greater than 60%. The SaL tumour was found to have the lowest mean aneuploid bromodeoxyuridine labelling index (LI) equal to 21%, while the highest LI of 35.8% was measured for the LLC tumour. The mean S-phase time was short, lasting 8.5 - 10.9 hrs. The potential doubling time (T(pot)) assessed by BrdUrd staining and flow cytometry were as follows: 37.1 hours for SaL, 22.7 hours for MCA and 21.4 hours for LLC tumour. The MCA had the shortest volume doubling time (T(d)) equal to 1.7 days and the longest one, equal to 4.7 days, was found for the LLC. The lowest cell loss was found in the MCA tumour (44%), while the highest in the LLC tumour (81%). As all the examined tumours proliferate rapidly, there is a capacity for accelerated repopulation and therefore the tumours seem to be good models for experimental radiotherapy.

Animals↗
PubMed1989

Model biological microemulsions: Part I--Phase behaviour and physicochemical properties of cholesteryl benzoate and sodium deoxycholate contained microemulsions.

Phase behaviour and some physicochemical properties of cholesteryl benzoate-contained microemulsions of xylene and heptane with water using sodium deoxycholate and butan-1-ol as surfactant and co-surfactant respectively have been studied. While the microemulsion area of xylene depends insignificantly on the surfactant/co-surfactant ratio, that of heptane shows appreciable dependence. At surfactant + co-surfactant percentage of 50 or above, both the systems become oil continuous. With respect to time and temperature, the microemulsion systems have been found to be very stable. At low percentage of water, the xylene system is considerably viscous; that of heptane is less viscous but shows viscosity maximum at 45% water. Cholesterol in xylene has given greater viscosity than cholesteryl benzoate. The equivalent conductance of both the systems increase with increasing water content and the values are comparable. Unlike normal electrolyte solutions, the products of equivalent conductance and viscosity (the Walden product) sharply rise with increased water content, which suggests a special mechanism of conduction via 'channel' formation. The overall rigidity of the microemulsions is suggested by their lower specific volumes and compressibilities at all compositions. The excess specific volumes and excess compressibilities at different percentages of water are presented.

Chemical Phenomena↗
PubMed2005

Development of invasive follicular cell carcinomas in a rat thyroid carcinogenesis model: biological impact of capsular inflammation and reduced cyclooxygenase-2 expression.

We have previously reported that thyroid capsular inflammation induced by sulfadimethoxine (SDM), a goitrogen, might play a role in development of invasive follicular cell adenocarcinomas in rats initiated with N-bis(2-hydroxypropyl)nitrosamine (DHPN). The present study was designed to examine the role of cyclooxygenase (COX)-2, widely known to be up-regulated in inflammatory states, during chemically induced rat thyroid carcinogenesis. Male F344 rats received a subcutaneous DHPN (2800 mg/kg) injection, and 1 week later were allowed free access to drinking water containing antithyroidal propylthiouracil (PTU, 0.003%) or SDM (0.1%) for 4 or 10 weeks. Control groups receiving goitrogen alone and no treatment were also included. At week 4, diffuse follicular cell hyperplasia was induced in all PTU- and SDM-treated groups, along with fibrous capsular thickening and capsular thickening with inflammation, respectively. Additionally, multiple focal follicular cell hyperplasias and adenomas were observed in the DHPN + PTU and DHPN + SDM cases. At week 10, adenocarcinomas invasive to the capsule and restricted to the capsular adjacent region, were frequent in the DHPN + SDM group, but not observed in the animals given DHPN + PTU. Western blots and immunohistochemistry revealed constitutive COX-2 expression in non-neoplastic follicular cells of the control and all of the PTU- and SDM-treated rats. However, COX-2 reactivity was significantly reduced or negative in the preneoplastic/neoplastic lesions in the DHPN-treated groups. In fibrous or inflamed thickened capsules, only a few component cells with inflammatory elements were positive for COX-2, and there was no significant difference in this regard between the PTU and SDM treatments. The present results suggest that capsular inflammation could play a role in development of invasive carcinomas, but COX-2 expression does not make a major contribution.

Adenocarcinoma, Follicular↗
PubMed1978

Experimental muscular amebiasis in hamsters as a biological model.

Trophozoites of Entamoeba histolytica maintained in vitro in Pavlova's medium were inoculated by deep intramuscular injection into the proximal left hindleg of hamsters. Thioglycollate medium was utilized as a successful vehicle to induce the infection. The invasion of the muscular tissue by the vegetative forms caused the formation of abscesses with great destruction of muscular fibers. The lesions were limited to the muscular tissue of the femoral area. The number of trophozoites, the medium of thioglycollate as a vehicle, the volume of the inoculum and the trauma caused by the needle were important elements in the evolution of the muscular amebic abscesses. A limited trial of the amebicidal activity of metronidazole utilizing the amebic intramuscular infection was also performed.

Abscess↗
PubMed2003

Gastrointestinal mucositis: a new biological model.

The history of research into gastrointestinal mucositis (GIM), and how the future directions are informed by the progress made in the study of oral mucositis (OM) are discussed. It is proposed that OM and GIM should both be considered to be elements of alimentary mucositis (AM), which covers mucosal damage through the entire alimentary tract, with regional differences being due to the specialized needs of each area.

Animals↗
PubMed2006

A biologic model to study the genetics of psychotic, mood, and anxiety disorders: the velocardiofacial syndrome.

Recent advances in molecular genetics have led to new insights on the velocardiofacial syndrome (VCFS). Most patients have a large deletion on one copy of chromosome 22 (encompassing up to 30 genes), which can be confirmed with genetic testing. A wide spectrum of psychiatric symptoms has been reported in patients with VCFS, including schizophrenia and bipolar disorder. Preliminary studies of candidate genes from the deletion region suggest that allelic differences may increase susceptibility to psychiatric disorders, but these studies await replication. Mouse models with genetically engineered deletions have the potential to isolate the genes associated with VCFS neuropsychiatric symptoms. VCFS is likely to represent the deficiency of several genes with complex interactions. Further psychiatric research is warranted to delineate more comprehensively the neuro-psychiatric phenotype associated with VCFS. Accurate psychiatric diagnosis will better inform and advance ongoing genetic research.

Alleles↗
PubMed1991

Hexagenia rigida (ephemeroptera) as a biological model in aquatic ecotoxicology: experimental studies on mercury transfers from sediment.

The accumulation of two mercury compounds--HgCl(2) and CH(3)HgCl--by Hexagenia rigida (burrowing mayfly nymphs) from contaminated sediments was investigated experimentally. Three exposure periods were selected: 7, 14 and 28 days. Results reveal a high capacity of this species for Hg accumulation and considerable differences between the two chemical forms of the metal. Thus, the amount of total mercury accumulated after 28 days' exposure would be 60 times greater for the organic form if the two compounds were initially added to the sediment in the same concentrations. No significant growth inhibition appears for the different experimental conditions studied. Data treatment at the organism level showed a positive linear correlation between the fresh weight and Hg content in the nymphs; this was especially marked when the exposure time was relatively long and Hg was in the form of CH(3)HgCl. The study of mercury distribution in the organs of Hexagenia rigida (gills and gut) and the examination of results obtained in similar experimental conditions after contamination of the nymphs via the water column showed the importance of the trophic route, via ingested sediment, for the bioaccumulation of the metal initially introduced into the sediment.

Journal Article↗