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Query: UMLS:C0155339 (Brown)
 12,436 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The course of browning was more rapid in mixtures of polyunsaturated fatty acid esters with casein that in those of the same lipids with formaldehyde-treated casein or with an inert inorganic substrate (barium sulphate or sodium sulphate). On the contrary, the content of oxidation products (peroxides and aldehydes) was much higher in lipids mixed with formaldehydetreated casein or with inorganic substrates. The results obtained with albumin were similar. The ratio of red to yellow pigments was higher in mixtures with non-treated casein than in the other two investigated reaction mistures. Brown pigments contained only low per centages of nitrogen.
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PMID:Nonenzymic browning. XI. Effect of free amino groups on browning reactions in lipid-protein mixtures. 114 20

In tests of the effects of restorative materials on dental pulp, it is important that one evaluate bacterial contamination, and this is usually done histologically. Preceding the usual paraffin-embedding of hard-tissue specimens for microscopical investigations, decalcification is performed. To study the influence of decalcifying agents (nitric acid, formic acid, and ethylenediamine tetraacetic acid) on the number and Gram-stainability of bacteria, we used a model system consisting of suspensions of formaldehyde-fixed Streptococcus faecalis. The Gram-positive organisms were stored in distilled water, in 4% formaldehyde solution, or in the decalcifying agents for various experimental periods. Counts were made by means of a hemocytometer, and smears were stained with the Brown and Brenn staining method. After periods which are averages for the decalcification of teeth, severe reductions of both the number and the Gram-positive stainability were found. After one week in formic acid, only one out of 15 organisms stained blue. With nitric acid and EDTA, the reductions were fewer. Since only blue-staining bacteria can be detected clearly in tissue sections, the results of these experiments indicate that, with limited numbers of organisms, the risk exists for false-negative scores for decalcified hard-tissue sections.
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PMID:Effect of histological decalcifying agents on number and stainability of gram-positive bacteria. 244 Sep 25

Previous publications on the National Toxicology Program (NTP)-sponsored mutagenicity testing program in Drosophila dealt with evaluations of chemicals following adult treatment (feed, injection). The current paper deals with a comparison between the laboratories at Brown University (BRU) and the University of Wisconsin at Madison (UWM) regarding the response of larvae to treatment with chemicals in the sex-linked recessive lethal (SLRL) test and, where appropriate, the reciprocal translocation test as well. Dimethylnitrosamine (DMN) and dimethylbenz(a)anthracene were used first as reference mutagens. Six coded compounds were then evaluated regarding their repeatability in the two laboratories; the compounds were benzo(a)pyrene, 3-methylcholanthrene, coumarin, quinoline, formaldehyde, and 9-aminoacridine. It was concluded that at this time it would be imprudent to forgo larval treatment in cases where compounds proved negative after adult feeding. Accordingly, testing a series of 20 compounds negative after adult treatment is in progress.
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PMID:Chemical mutagenesis testing in Drosophila. VI. Interlaboratory comparison of mutagenicity tests after treatment of larvae. 251 Oct 11

Tumor BN472, a malignant mammary adenocarcinoma, was subcutaneously transplanted into syngeneic female Brown Norway rats. Seven days after tumor inoculation, carrageenan-impregnated synthetic sponges were subcutaneously implanted in control and tumor-bearing rats. Another week later the animals were sacrificed and alveolar macrophages were harvested and tested for tumoricidal activity against a tissue culture line of BN472 cells and their capacity to phagocytose formaldehyde-treated sheep erythrocytes. The data demonstrate that carrageenan statistically significantly enhances the tumoricidal activity of alveolar macrophages in tumor-bearing rats. Phagocytic activity of the macrophages in these animals is not different from sham-operated control animals, whereas the phagocytic activity of tumor-bearing rats is statistically significantly decreased.
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PMID:Role of alveolar macrophages in tumor-bearing rats: tumoricidal properties of carrageenan-activated macrophages. 322 48

Six recessive second chromosomal mutants of Drosophila melanogaster exhibiting larval hypersensitivity to methyl methanesulfonate have been identified and assigned to six complementation groups. The strains have been analyzed for their sensitivities to UV, X-ray, nitrogen mustard and formaldehyde. Two classes of mutants not previously observed in Drosophila have been identified. The mus 204A1 and mus 205A1 mutants exhibit sensitivity to MMS and UV but not X-ray or nitrogen mustard, while the mus 206A1 and mus 207A1 mutants display sensitivity to MMS, UV, and nitrogen mustard. Four of the seven strains exhibit poor female fertility and two of these are shown to have a weak meiotic disjunctional defect. Biochemical studies of the mus 205A1 mutant suggest a defect in DNA synthetic ability associated with excision and postreplication repair performed on UV and alkylation-damaged templates (Boyd and Harris 1981; Brown and Boyd 1981 b; R.L. Dusenbery, manuscript in preparation).
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PMID:Mutagen sensitivity of Drosophila melanogaster. V. Identification of second chromosomal mutagen sensitive strains. 681 27

The local lymph node assay (LLNA) and the IgE test in the mouse are proposed models for predictive recognition of low molecular weight chemicals causing IgE-mediated allergic airway reactions in man. Since rats are commonly used in routine toxicity studies and a previous study (Arts et al. (1996) Food Chem. Toxicol. 34, 55-62) has shown that several rat strains were found appropriate for the LLNA, the suitability of the rat for the IgE test was examined in the present study. Serum IgE concentrations were examined following topical exposure of Brown Norway (BN) and Wistar rats to each of four chemicals with known diverse sensitization potential in humans: trimellitic anhydride (TMA), a dermal and respiratory sensitizer, dinitrochlorobenzene (DNCB), a dermal sensitizer with no or limited potential to cause respiratory allergy; formaldehyde (FA), a skin irritant and dermal sensitizer with equivocal evidence for respiratory sensitizing potential; methyl salicylate (MS), a skin irritant devoid of sensitizing properties. Of the four tested chemicals, only exposure to TMA resulted in a significant increase in serum IgE concentration and this response was only evoked in the high-IgE-responding BN rat. The latter two chemicals were also tested for lymph node activation, in casu the ear-draining lymph nodes. FA caused a dose-dependent activation of the draining lymph nodes whereas MS was inactive. The results as obtained with TMA, DNCB and MS in the rat are in agreement with human data. The results with FA though, indicate the need for further studies of chemicals that have both irritant and sensitizing properties at about similar concentrations or may act through non-IgE-mediated immune mechanisms.
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PMID:Local lymph node activation and IgE responses in brown Norway and Wistar rats after dermal application of sensitizing and non-sensitizing chemicals. 905 2

Treatment of cultured neurons with non-ionic detergents under certain conditions causes the axonal microtubules to splay apart from each other, allowing individual microtubules to be visualized by immunofluorescence microscopy [Brown et al., 1993, J. Cell Sci. 104: 339-352]. I have investigated whether axonal neurofilaments separate from each other under similar conditions. Cultures of dissociated dorsal root ganglion (DRG) neurons from fetal rats were treated with non-ionic detergent and fixed with formaldehyde. Neurofilaments were visualized by immunofluorescence microscopy using a polyclonal antiserum specific for NF-L. Treatment of the neurons with Triton X-100 or saponin caused filamentous structures to splay apart from each other along the entire length of the axon. Quantitative analysis of fluorescence intensity along the filamentous structures indicated that many of them represent single neurofilaments and that single and bundled neurofilaments can be distinguished based on their fluorescence intensity. The extent of this splaying phenomenon was dependent on time and detergent concentration. Temporal analysis indicated that short portions of single neurofilaments initially loop out from the axonal bundle and then subsequently splay apart further along their length and adhere to the polylysine/laminin coated substrate. The maximum observed length for a single axonal neurofilament was 183 microm in neurons after only 1 day in culture, which indicates that neurofilaments can attain remarkable lengths in these young cultured neurons. The splayed axonal cytoskeleton preparation described here allows individual axonal neurofilaments to be visualized by immunofluorescence microscopy, which is not possible in conventional preparations due to the dense packing of these polymers in axons.
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PMID:Visualization of single neurofilaments by immunofluorescence microscopy of splayed axonal cytoskeletons. 933 Dec 18

We have examined lipid peroxidation (LPO) and fatty acid acyl chain dynamics in synaptosomal membranes isolated from aged rat (Fischer 344 x Brown Norway F1 hybrids) brains, correlating these results with measurements of enzymatic activity of the synaptic plasma membrane Ca2(+)-ATPase (PMCA). Calcium-dependent ATPase activity in these membranes exhibits progressive decreases with a maximal loss of activity with age of approximately 35%. The sensitivity of this membrane-bound ion transporter to the lipid composition of the surrounding membrane, as well as the high abundance of oxidatively sensitive polyunsaturated fatty acyl chains in synaptosomal membranes, suggests that this age-related loss in catalytic turnover may result from LPO-mediated protein modification and/or changes in the physical structure of the bilayer. However, high-performance liquid chromatography analysis of 2,4-dinitrophenylhydrazone derivatives reveals no significant age-related increases in the content of reactive aldehydes (malondialdehyde, formaldehyde, acetaldehyde or acetone) which comprise breakdown products of lipid peroxidation. Electron paramagnetic resonance measurements employing 5- and 12-stearic acid spin labels with the nitroxide reporter groups at two depths in the bilayer were used to assess the fatty acyl chain dynamics (fluidity) of synaptosomal membranes. The resulting spectra demonstrate anisotropic lipid dynamics of two populations of lipids, i.e. lipids in direct association with membrane proteins (boundary lipids) and bulk lipids that do not directly associate with proteins. The nanosecond dynamics of both lipid populations is unaltered with age indicating that any compositional changes occurring with age are insufficient to result in alterations in bilayer fluidity relevant to PMCA activity. Thus, the observed age-related decline in PMCA activity may be explained by direct modification of membrane protein.
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PMID:Decrease in Ca-ATPase activity in aged synaptosomal membranes is not associated with changes in fatty acyl chain dynamics. 986 36

The interaction between Fas and its ligand (FasL) induces apoptosis in the Fas-expressing cell. We hypothesized that liposome-mediated FasL gene transduction to the lung allograft, in addition to low-dose immunosuppression, might reduce acute rejection. Orthotopic left lung allotransplantation was performed in male rats (Brown Norway to Fischer F344). FasL gene transfer was performed by use of the plasmid pBCMGSNeo carrying the gene coding for murine FasL and the cationic liposome GL#67:DOPE. Six hundred and sixty micrograms of DNA in 250 microl H2O and 0.5 micromol GL#67 in 250 microl H2O were diluted to 5 ml with saline solution. This emulsion (20 degrees C) was instilled retrogradely through the left pulmonary vein after flushing with LPD solution (20 ml, at 4 degrees C). Subsequently, the graft was stored at 10 degrees C for 3 h. A single dose of cyclosporine A (CsA; 2.5 mg/kg i.m.) was given to all groups 48 h after the transplantation. In group 1 (n = 6), FasL/GL#67 was instilled as described. In group 2 (n = 5), GL#67 was given without DNA. Group 3 (n = 5) animals received CsA only. Five days after transplantation, gas exchange was assessed after exclusion of the contralateral native lung (FiO2 = 1.0). Grafts were flushed with saline solution and fixed in formaldehyde for histological evaluation. No statistical difference in gas exchange (PaO2) between the two control groups 2 (6.4 +/- 0.4 kPa) and 3 (7.4 +/- 0.4 kPa) could be detected 5 days postoperatively (P = 0.9). In contrast, grafts transduced with FasL (group 1) had significantly better gas exchange on postoperative day 5 (PaO2: group 1 37.0 +/- 10.6 kPa vs group 2 6.4 +/- 0.41 kPa; P = 0.002). Two animals in group 1 revealed no or only minimal improvement in gas exchange. Histologically, all lung specimen of all groups showed signs of acute rejection (A2). Leukocyte infiltrates, rated by two independent observers, were less severe in all group 1 animals. Liposome-mediated FasL gene transfer at the time of harvest in combination with low-dose CsA reduces acute rejection in four out of six animals in this model of rat lung allotransplantation.
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PMID:Fas ligand gene transfer combined with low dose cyclosporine A reduces acute lung allograft rejection. 1111 24

Changes in histology and Th1- and Th2-related cytokines expression in nasal mucosa were examined in Brown Norway (BN) and Fischer 344 (F344) rats after 5-day inhalation of 1% formaldehyde aerosol. In F344 rats, mucosal lesions characterized by degeneration and/or desquamation of epithelial cells with neutrophil infiltration were observed at all levels of nasal cavity and all kinds of mucosal epithelia were involved in such lesions. In BN rats, mucosal lesions were milder and the olfactory epithelium was free from lesions. The levels of Th1-related cytokines (IFN-gamma and IL-2) were significantly depressed and those of Th2-related cytokines (IL-4 and IL-5) also tended to be depressed in BN rats. In F344 rats, similar but much less clear alterations in the levels of Th1- and Th2-related cytokines were observed. Such results of measurement of Th1- and Th2-related cytokines mRNAs seem to be interesting although their significance is still obscure.
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PMID:Rat strain difference in histology and expression of Th1- and Th2-related cytokines in nasal mucosa after short-term formaldehyde inhalation. 1271 Jul 11


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