Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C1275122 (TEM)
 21,810 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mononuclear cells (10--20 X 10(6)) obtained from human peripheral blood by a standard Ficoll-Hypaque technique were suspended in RPMI 1640 media at 4 degrees C containing 10% foetal calf serum and 7-5% dimethyl sulphoxide (DMSO). Two-millilitre aliquots were cooled at -1 degree C/min in a Cryoson BV-4 programmed freezing system to -30 degrees C, then -5 degrees C/min to -80 degrees C and stored in liquid nitrogen vapor. On the day of testing, cell suspensions were thawed rapidly in a 37 degree C water bath. DMSO was diluted slowly out of the sample and cells resuspended in fresh RPMI 1640. It was found that frozen stored human lymphocytes (FSHL) demonstrated all the characteristics of fresh unfrozen cells. These included their ability to form spontaneous rosettes with sheep erythrocytes ('E' rosettes) and sheep erythrocyte--antibody--complement rosettes ('EAC' rosettes). The presence of surface immunoglobulins and Fc receptors were shown by membrane immunofluorescence to be comparable. In addition, the results show that FSHL respond to mitogens, specific antigens; act as both stimulators and responders in the mixed lymphocyte culture reaction; and exhibit cell-mediated lymphocytotoxicity following in vitro sensitization, or against antibody-coated target cells.
 ...
PMID:Immunological responsiveness of frozen-thawed human lymphocytes. 12 29

The need to screen potential chemical pollutants for mutagenicity has increased with the increasing volume of such materials being introduced into natural water. The present study demonstrates the utility of a fish, the guppy (Poecilia reticulata), as a model test system in which water-borne chemical mutagens may be assayed for dominant lethal effects. Mature male guppies were injected with three doses of triethylenemelamine (0.1, 0.2 and 0.4 mg/kg) in addition to a control sham treatment. Each male was subsequently mated to virgin females. In an alternative test, male fish were allowed to swim in triethylenemelamine solutions of known concentration for a period of 24 h prior to being mated to virgin female guppies. 10 days following matings, females were dissected, and numbers of live and dead embryos were recorded. Significant dose effects were demonstrated by analysis of variance techniques in both the injection and the emersion tests with the results showing higher percentages of dead embryos and lower total number of embryos with increasing doses of TEM.
 ...
PMID:Dominant lethal effects of triethylenemelamine in the guppy Poecilia reticulata. 36 86

The aim of the paper is to provide pertinent, information about scanning electron microscopy (SEM), with a detailed survey on the great possibilities of SEM which is becoming increasingly important in research and practical work of forensic medicine. The electronoptical characteristics of the method are discussed and the basic preparation methods to be selected are described. The areas of forensic medicine where these methods have already been used, as well as the results obtained, are briefly surveyed. The present state of affairs as well as personal experiences with hairs, bones, muscle and skin are described in detail. The experience with the critical point drying method is described. This method according to the reviewers, is very useful for work with hairs, bones, nails and sometimes with skin although the preparation may result in secondary destructions of the tissues of high water content to such an extent that the evaluation will be interfered with or becomes impossible. Further possibilities of these perspectivic methods are under research. The discussion of the physiological data is preceded by a historical description of the SEM and TEM systems and the basic principles of its function, which should facilitate reading of the text.
 ...
PMID:On the possibilities of the application of scanning electron microscopy in the forensic medicine. 60 50

The water-rich phase (tissue channels) of the intersititial tissue in rat ileum, knee joint capsules, kidneys, and implanted Guyton's capsules was examined electron microscopically by the SEM of plastic injection models, and by TEM and HVEM of ferrocyanide and ferritin as tracers. It was shown that the channels do in fact exist, and are not just vacuoles. Quantitative estimations of their numbers and diameters were made. These agreed well with estimates made by other methods.
 ...
PMID:The quantitative morphology of interstitial tissue channels in some tissues of the rat and rabbit. 72 12

This paper describes a simple technique for consistent production of clean, unwrinkled, flat thin (500-1000 A) sections for TEM and thick (1/2-1 micron) sections for HVEM mounted on Formvar-covered slot grids for use in conventional and high voltage electron microscopy. The technique centers around use of a Formvar-covered aluminum supporting rack onto which slot grids that contain sections suspended in water are placed.
 ...
PMID:A simple procedure for mounting wrinkle-free sections on formvar-coated slot grids. 80 Jun 84

Ultrastructural analysis including scanning and transmission electron microscopic studies (SEM and TEM) were carried out on oyster gill tissue after exposure either to serum fractions from individuals homozygous or heterozygous for cystic fibrosis (CF), to comparable serum fractions from normal individuals, or to sea water. In 4 of the experiments examined topologically (SEM), the CF sera (either heterozygous or homozygous) stimulated the production of mucus that was found in close association with the cilia. The association of excessive mucus with the cell surface could be responsible, in part, for the well-known inhibition of ciliary activity by a factor in CF serum. In 3 additional SEM experiments involving shorter treatment times, very little difference could be observed between homozygous CF, heterozygous CF, and normal serum-fraction-treated oyster tissues. In parallel experiments, ultrathin sections of gill tissue were examined by means of TEM. Those samples that were responsive, as determined by TEM, displayed several characteristic features, including enlarged and partially exuded goblet cells, altered mucus structure along with twisted and matted cilia. An overall swelling of the gill filament was also observed in the responsive tissues. From TEM analysis no detectable alteration in fine structure was apparent in gill tissues that were treated with sera from heterozygous or normal individuals.
 ...
PMID:Effects of cystic fibrosis serum ciliary inhibitor on oyster gill ultrastructure: analysis by scanning and transmission electron microscopy. 99 86

Using STEM dark field images, we have determined linear mass densities and radial density profiles of vitrified helical particles. The samples studied are: TMV, RNA-free helical polymers of TMV coat protein (TMV-P), Salmonella typhimurium bacterial flagellar filaments and Escherichia coli pili. The difference between the profiles obtained for TMV and TMV-P shows a maximum at a radius of about 4 nm, corresponding to the RNA in TMV. Of the peaks that are resolved in X-ray diffraction analysis we can resolve the ones for TMV at radii of approximately 4.2 and approximately 6.7 nm and a shoulder at approximately 7.8 nm. Density peaks in bacterial flagellar filaments appear at radii of approximately 4.2, approximately 6.5, approximately 8.5, and approximately 10.5 nm. Accurate mass data can be obtained if the filaments are embedded in ice layers of uniform thickness; their diameters need to be similar to that of the mass standard (TMV) when these data are measured in a comparative manner. Ice layers are often not uniform, and thickness variations are well revealed in STEM dark field. The signal-to-noise ratio and contrast for the transverse projections are lower than those measured for freeze-dried specimens: half an order and one order of magnitude, respectively. The thinnest uniformly thick ice layer still containing a single layer of particles is approximately 10-15 nm thicker than the particles. Radial mass density functions that are directly determined in STEM may have a potential use as substitutes for the unreliable equatorial data in helical reconstructions of TEM bright field images of vitrified specimens.
 ...
PMID:Radial mass density functions of vitrified helical specimens determined by scanning transmission electron microscopy: their potential use as substitutes for equatorial data. 136 14

This paper describes four investigations of the olfactory mucosa of the brown trout: 1) the ultrastructure of the olfactory mucosa as revealed by scanning (SEM), conventional transmission (TEM), and high voltage (HVEM) electron microscopy; 2) light and electron-microscopic investigations of retrograde transport of the tracer macromolecule horseradish peroxidase (HRP) when applied to the cut olfactory nerve; 3) SEM and TEM investigations of the effects of olfactory nerve transection on cell populations within the olfactory epithelium; and 4) ultrastructural investigations of reversible degeneration of olfactory receptors caused by elevated copper concentrations. The trout olfactory epithelium contains five cell types: ciliated epithelial cells, ciliated olfactory receptor cells, microvillar olfactory receptor cells, supporting cells, and basal cells. The ciliated and microvillar olfactory receptor cells and a small number of basal cells are backfilled by HRP when the tracer is applied to the cut olfactory nerve. When the olfactory nerve is cut, both ciliated and microvillar olfactory receptor cells degenerate within 2 days and are morphologically intact again within 8 days. When wild trout are taken from their native stream and placed in tanks with elevated copper concentrations, ciliated and microvillar cells degenerate. Replacement of these trout into their stream of origin is followed by morphologic restoration of both types of olfactory receptor cells. Ciliated and microvillar receptor cells are primary sensory bipolar neurons whose dendrites make contact with the environment; their axons travel directly to the brain. Consequently, substances can be transported directly from the environment into the brain via these "naked neurons." Since fish cannot escape from the water in which they swim, and since that water may occasionally contain brain-toxic substances, the ability to close off--and later reopen--this anatomic gateway to the brain would confer a tremendous selective advantage upon animals that evolved the "brain-sparing" capacity to do so. Consequently, the unique regenerative powers of vertebrate olfactory receptor neurons may have their evolutionary origin in fishes.
 ...
PMID:Ultrastructural neurobiology of the olfactory mucosa of the brown trout, Salmo trutta. 139 70

During the last 20 years, existing data show that caries activity has decreased in some industrialized countries, while marked increases have occurred, often rapidly, in developing countries. Changes in the prevalence of a multifactorial disease like dental caries are difficult to explain but seem to coincide either with increased intake of refined sugar-containing feeding or with the widespread availability of fluorides from many sources, more particularly in the tooth-pastes. The combination of fluorides with different other factors must be considered to explain the reduction in caries prevalence in the 1970's, but only the cariostatic effect of fluorides can be measured significantly. In spite of few studies in Belgium, a trend to a reduction of caries prevalence has been observed in temporary and permanent dentition. The aims of this study are to assess: 1. the oral health in a population of 5 to 21 old schoolchildren 2. and the effect of water naturally fluoridation on the dental caries prevalence. The dental caries prevalence is determined in each age group using the dft, dfs, D (2-4) MFT and D (2-4) MFS indices. The situation in this population is not satisfactory and there is a marked need for better oral health. The D (2-4) MFT increases from 1.67 to 11.29 between 6 and 20 years of age. In each age group, the numbers of carious and untreated surfaces in temporary and permanent dentition are more important than the number of filled surfaces. The percentage of children with caries-free teeth decreases from 27.0 to 0% between 5 and 20 years of age. A relation is recorded between the caries indices and the socio-economic category of the father, with the lowest indices among the higher educational group. The results show that the prevalence of dental caries is significantly lower in lifetime residents of the fluoridated community (Mouscron). Fluoridation reduces but does not eliminate social inequalities. The benefits of water fluoridation have been demonstrated in most countries but fluoridation alone is not sufficient to achieve total prevention.
 ...
PMID:[Dental caries in a Belgian school population of 5-to-21-year-olds]. 148 Jul 89

Cells cultured on transparent conductive substrates (glass coated with indium oxide) were fixed with aldehyde and osmium tetroxide and then treated with tannic acid, uranyl acetate and lead citrate. The same cell culture preparation could be sequentially studied by light microscopy (in water immersed condition), SEM (after dehydration and critical point drying) and TEM (after embedding in an epoxy resin). This method ensures the preservation of intact cell morphology, cell surface topography and intracellular structures. The treatments used render the cells conductivity and permit to carry out successfully SEM of uncoated cells cultured on conductive substrates. This method also provides a higher contrast of TEM images.
 ...
PMID:[A method for the chemical treatment of cells for the purpose of the subsequent study of the same cell culture preparation by light, scanning and transmission electron microscopy]. 170 38


1 2 3 4 5 6 7 8 9 10 Next >>