Search PubMed⌕ Search

Biomedical subjects

C C Miller

Publications and source records attributed to C C Miller.

At least 145 records · Page 8Linked to original sources
PubMed1988

Ability of 15-hydroxyeicosatrienoic acid (15-OH-20:3) to modulate macrophage arachidonic acid metabolism.

Mouse peritoneal macrophages metabolize dihomogammalinolenic acid (20:3n-6) primarily to 15-hydroxy-8,11,13-eicosatrienoic acid (15-OH-20:3). Since the biological properties of this novel trienoic eicosanoid remain poorly defined, the effects of increasing concentrations of 15-OH-20:3 and its arachidonic acid (20:4n-6) derived analogue. 15-hydroxy-5,8,11,13-eicosatetraenoic acid (15-HETE), on mouse macrophage 20:4n-6 metabolism were investigated. Resident peritoneal macrophages were prelabeled with [3H]-20:4n-6 and subsequently stimulated with zymosan in the presence of either 15-OH-20:3 or 15-HETE (1-30 microM). After 1 hr, the radiolabeled soluble metabolites were analyzed by reverse phase high performance liquid chromatography. 15-OH-20:3 inhibited zymosan-induced leukotriene C4 (IC50 = 2.4 microM) and 5-HETE (IC50 = 3.1 microM) synthesis. In contrast to the inhibition of macrophage 5-lipoxygenase, 15-OH-20:3 enhanced 12-HETE synthesis (5-30 microM) and had no measurable effect on cyclooxygenase metabolism (1-10 microM) i.e., 6-keto-prostaglandin F1 alpha and prostaglandin E2 synthesis. Addition of exogenous 15-HETE produced similar effects. These results suggest that the manipulation of macrophage 15-OH-20:3n-6 levels may provide a measure of cellular control over 20:4n-6 metabolism, specifically, leukotriene production.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1988

Utilization of dihomo-gamma-linolenic acid (8,11,14-eicosatrienoic acid) by murine peritoneal macrophages.

This study examined the metabolism of dihomo-gamma-linolenic acid (20:3(n-6] in casein-elicited murine peritoneal macrophages. Cells were incubated with [14C]20:3(n-6) in the presence of 1% fetal bovine serum (FBS) or 0.025% bovine serum albumin (BSA), and the distribution and identity of membrane-bound and soluble products were determined. Approx. 70-80% of the [14C]20:3(n-6) was recovered in membrane phospholipids. The distribution of radiolabel in individual cellular phospholipids revealed a time-dependent (6 vs. 16 h) increase in the percentage of radiolabel esterified to phosphatidylethanolamine (PE). Analysis of cellular total lipids following transmethylation indicated that approx. 4, 2 and 9% of the incorporated 20:3(n-6), respectively, had been desaturated and elongated into 20:4(n-6), 22:4(n-6) and 22:3(n-6). When cells prelabeled for 16 h were incubated in the presence of the divalent cation ionophore, A23187, or zymosan for 30-60 min, two radiolabeled metabolites were isolated in the incubation supernatant. These metabolites were identified as 12-hydroxy-8,10,14- and 15-hydroxy-8,11,13-eicosatrienoic acids, as determined by reverse-phase and normal-phase high-performance liquid chromatography. The generation of monohydroxy fatty acids was notably absent in prelabeled quiescent cells and A23187-stimulated cells incubated with BW755C, a dual cyclooxygenase and lipoxygenase inhibitor. We conclude that casein-elicited murine peritoneal macrophages can extensively metabolize 20:3(n-6) through delta 5-desaturase, elongase and oxygenation reactions.

8,11,14-Eicosatrienoic Acid↗
PubMed1988

Oxidative metabolism of dihomogammalinolenic acid by guinea pig epidermis: evidence of generation of anti-inflammatory products.

Reports that vegetable oils which contain gamma-linolenic acid (18:3n-6) may exert beneficial effects on cutaneous disorders prompted us to investigate whether epidermis possesses the ability to transform dihomogammalinolenic acid (20:3n-6), the epidermal elongase product of 18:3n-6, into oxidative metabolites with anti-inflammatory potential. Incubations of [1-14C]20:3n-6 with the 105,000 g particulate (microsomal) fraction from guinea pig epidermal homogenate resulted in the formation of the 1-series prostaglandin PGE1. The identity of this product was confirmed by argentation thin-layer chromatography (TLC), reverse phase-HPLC, and conversion with alkali treatment to PGB1. Incubations of [1-14C]20:3n-6 with the 105,000 g supernatant (cytosolic) fraction from guinea pig epidermal homogenate resulted in the formation of the 15-lipoxygenase product 15-hydroxy-8, 11, 13-eicosatrienoic acid (15-OH-20:3n6). The identity of this product was confirmed by normal phase-HPLC and gas chromatography/mass spectrometry (GC/MS). Thus, data from these studies indicate the capacity of enzymes in the microsomal and cytosolic fractions of guinea pig epidermal homogenates to transform 20:3n-6 to the eicosanoids PGE1 and 15-OH 20:3n-6, products which reportedly have anti-inflammatory properties. The in vivo significance of these findings remains to be explored.

8,11,14-Eicosatrienoic Acid↗
PubMed1987

Monoclonal antibodies against plant proteins recognise animal intermediate filaments.

Four monoclonal antibodies were raised against polypeptides present in a high-salt detergent-insoluble fraction from cells of Chlamydomonas reinhardtii. Indirect immunofluorescence microscopy of fibroblasts and epithelial cells grown in culture using these plant antibodies revealed staining arrays identical to those obtained with well characterised antibodies to animal intermediate filaments. Immunofluorescence microscopy of Chlamydomonas with these monoclonal antibodies and a monoclonal antibody that recognises all animal intermediate filaments (anti-IFA) gave a diffuse, patchy cytoplasmic staining pattern. Both the plant antibodies and anti-IFA stained interphase onion root tip cells in a diffuse perinuclear pattern. In metaphase through to telophase, the labelling patterns colocalised with those of microtubules. Labelling of the phragmoplast was also detected but not staining of the preprophase band. On Western blots of various animal cell lines and tissues, all the antibodies labelled known intermediate filament proteins. On Western blots of whole Chlamydomonas proteins, all the antibodies labelled a broad band in the 57,000 Mr range, and three antibodies labelled bands around 66,000 and 140,000 Mr but with variable intensities. On Western blots of whole onion root tip proteins, all the antibodies labelled 50,000 Mr (two to three bands) polypeptides and a diffuse band around 60,000 Mr and three of the antibodies also labelled several polypeptides in the 90,000-200,000 Mr range. The consistent labelling of these different bands by several different monoclonal antibodies recognising animal intermediate filaments makes these polypeptides putative plant intermediate filament proteins.

Antibody Specificity↗
PubMed1987

Staining with monoclonal antibodies to neurofilaments distinguishes between subpopulations of neurofibrillary tangles, between groups of axons and between groups of dendrites.

A new monoclonal antibody (mab) against neurofilaments is described (mab 1215) and its reactions compared with previously characterized mabs (BF10; RT97). Mab 1215 recognizes an epitope on the heavy neurofilament polypeptide (NF-H). In Alzheimer's disease, mab 1215 recognizes only a subpopulation of neurofibrillary tangles and stains a proportion of tangles in the hippocampus but none of those in the olfactory bulb. However, mabs RT97 and BF10 stain the majority of tangles in both brain areas. Of the three antibodies, only mab BF10 recognizes, specifically, axons of granular cells in the dentate gyrus of the hippocampus. Mab 1215 recognizes more dendrites in the pyramidal layer than either mab BF10 or mab RT97. Our observations indicate that neurofilaments are not identical in all axons and that, contrary to previous reports, NF-H is present in dendrites. The dendritic form of NF-H appears to be different from NF-H in axons and this could be due to differences in the state of phosphorylation of NF-H. We suggest that the finding that distinct subpopulations of tangles exist indicates that tangles are not static lesions. Further investigations into this possibility may illuminate the pathophysiology of Alzheimer's disease.

Aged↗
PubMed1987

Neurofibrillary tangles and the neuronal cytoskeleton.

Antibodies to neurofilaments and the microtubule-associated protein, tau, have been used with anti-paired helical filament (PHF) serum to study Alzheimer neurofibrillary tangles. Tangles and their constituent PHF contain epitopes derived from or cross-reactive with both neurofilaments and tau proteins. These same structures are labelled with anti-PHF antibodies. A component of the anti-PHF serum is against tau proteins. We conclude that PHF are at least in part derived from an abnormal neuronal cytoskeleton.

Alzheimer Disease↗
PubMed1986

Alzheimer's paired helical filaments share epitopes with neurofilament side arms.

A panel of monoclonal antibodies to neurofilaments have been investigated with regard to the location of their respective epitopes on neurofilament polypeptides and their ability to label the neurofibrillary tangles and paired helical filaments (PHF) which are characteristic of Alzheimer's disease. All of the neurofilament monoclonal antibodies that label tangles and PHF are directed against epitopes in the side arm domains of the two larger neurofilament polypeptides, NF-H and NF-M, and do not recognise the alpha-helical rod domains of these proteins. Immuno-electron microscopy demonstrates that the neurofilament antibodies label the constituent PHF per se and do not simply stain neurofilaments that might be admixed with PHF. These neurofilament epitopes are differentially retained by PHF, following isolation. Thus, antibody labelling of PHF is not simply due to the presence of normal neurofilament polypeptides. We propose that in tangle-bearing neurons, neurofilaments are degraded by proteases and that it is fragments of the side arms which contribute to the composition of PHF.

Alzheimer Disease↗
PubMed1986

Transglutaminase and the neuronal cytoskeleton in Alzheimer's disease.

Transglutaminase [EC 2.3.2.13, (R)-glutaminyl-peptide:amine gamma-glutamyltransferase], an enzyme that catalyzes the introduction of glutamine-lysine cross-links into proteins, was purified. Neurofilament and microtubule proteins were substrates for this enzyme but the insoluble neurofibrillary tangles (NFT) isolated from Alzheimer's disease brain were not substrates. In vitro cross-linking of neurofilaments and microtubules by the enzyme did not produce paired helical filaments (PHF), which are the major ultrastructural component of NFT. These results make it unlikely that PHF are formed by the straightforward cross-linking of neurofilaments or microtubules.

Alzheimer Disease↗
PubMed1983

Immunofluorescence microscopy of the flagella and multilayered structure in two mosses, Sphagnum palustre L. and Polytrichum juniperinum Hedw.

Antibody against tubulin from porcine brain was used to examine the distribution of tubulin in developing spermatids of Polytrichum and mature spermatozoids of Sphagnum. Cells were prepared for indirect immunofluorescence microscopy after fixation in buffered paraformaldehyde and brief incubation in cellulase. Pretreatment with cold methanol resulted in considerably enhanced immunofluorescence but exposure to Triton X-100, with or without sonication, had no effect. The antibody showed similar immunological cross-reactivity with the flagella (both basal bodies and axonemes) and the spline microtubules of the multilayered structure. This is the first direct evidence that this rigid array of stable cytoskeletal microtubules consists of tubulin. Particularly intense fluorescence from the lamellar strata of the MLS in developing spermatids provides strong support for the notion that the lamellae comprise a highly structured microtubule organizing centre (MTOC), responsible for the ordered assembly of the overlying spline tubules. The demonstration of immunological cross-reactivity with antitubulin from porcine brain tubulin, within a plant structure other than fully formed microtubules, suggests that immunocytochemistry may have considerable potential for the detection of other MTOCs. By contrast, no detectable fluorescence emanated from the granular matrix cementing the flagellar basal bodies to the spline or the spindle-shaped sheath of fibres present in the spermatozoids of Sphagnum. Disruption of the mature gametes by sonication and treatment with Triton X-100 reveals the presence of particularly strong links between the spline and subjacent nuclear envelope.

Fluorescent Antibody Technique↗
PubMed1978

Development, manufacture, and distribution of animal drugs.

Much effort goes into the research, development, and manufacture of quality drugs to be used by the dairy producers. Food and Drug Administration aids in the process by establishing minimal requirements, reviewing data, and approving products conforming to their regulations. To misuse products or drugs is an invitation to trouble since little is known about the safety or efficacy of drugs other than for the manner in which they are labeled. Thus, the key to wise use of drugs is to read the label instructions.

Animals↗