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2.
Clin Microbiol Infect ; 17(5): 780-4, 2011 May.
Article in English | MEDLINE | ID: mdl-21521415

ABSTRACT

Meningitis is associated with an imbalance between matrix metalloproteinases (MMPs) and endogenous tissue inhibitors of MMP (TIMPs). Serum and CSF were collected prospectively from all patients with meningitis between January 2008 and December 2008 to measure the concentrations of MMP/TIMP in those patients who underwent a lumbar puncture for a presumptive diagnosis of meningitis. A total of 199 patients were enrolled into the study. The concentrations of CSF MMP-9 and TIMP-1 were significantly higher in the meningitis group compared with the control group (p 0.032 and p <0.001, respectively). However, the CSF TIMP-4 levels were significantly lower in the meningitis groups compared with the control groups (p <0.001). Patients with bacterial meningitis had higher CSF MMP-9 and TIMP-1 levels than those who had aseptic meningitis and controls. Patients with various infectious meningitis etiologies tended to have higher CSF MMP-9 expression by gelatin zymography when compared with the controls. In conclusion, MMP/TIMP system dysregulation was found in patients with meningitis, and CSF MMP and TIMP might act as novel indicators in patients with meningitis.


Subject(s)
Matrix Metalloproteinases/blood , Matrix Metalloproteinases/cerebrospinal fluid , Meningitis/enzymology , Tissue Inhibitor of Metalloproteinases/blood , Tissue Inhibitor of Metalloproteinases/cerebrospinal fluid , Humans , Meningitis/diagnosis , Prospective Studies
3.
Med Vet Entomol ; 23(2): 141-7, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19309438

ABSTRACT

The effect of humidity on the activity of Metarhizium anisopliae IP 46 (Metsch.) Sorokin (Hypocreales: Clavicipitaceae) formulated in sunflower oil against Aedes aegypti (L.) (Diptera: Culicidae) eggs was examined. After exposure of eggs at 75% relative humidity (RH) for 98% RH, eclosion was 98% RH, followed by: (a) a 12-day exposure at 75% RH before submersion in water; (b) a minimal 5-day exposure at > 98% RH and direct subsequent transfer of treated eggs to water, or (c) a minimal daily 20-h exposure at > 98% RH alternating with 4 h at 75% RH for 10 days. We demonstrate that oil-based formulations of conidia of M. anisopliae enhance ovicidal activity at high humidities and conclude that these formulations have potential in the integrated control of Ae. aegypti.


Subject(s)
Aedes/microbiology , Metarhizium/physiology , Mosquito Control/methods , Ovum/microbiology , Animals , Pest Control, Biological
4.
Transplant Proc ; 40(8): 2704-5, 2008 Oct.
Article in English | MEDLINE | ID: mdl-18929840

ABSTRACT

OBJECTIVES: Our previous study noticed remarkably elevated titers of anti-high-mobility group box 1 (HMGB1) antibodies in sera during the tolerance induction phase of a rat tolerogenic orthotopic liver transplantation (OLT) as well as in sera of clinically drug-free patients. We hypothesized that the release of nonhistone nuclear protein HMGB1 during rejection may play a pathogenic role in deteriorating post-OLT graft functions, such as inducing liver fibrosis. This study sought to investigate whether HMGB1 can directly activate hepatic stellate cells (HSCs) and drive them toward fibrogenesis. METHODS: The cultured HSCs were treated with recombinant HMGB1. RT-PCR and Western blotting analysis were used to measure alpha-smooth muscle actin (alpha-SMA) expression. Conditioned media were collected for gelatin zymography to monitor the activities of collagen-degrading matrix metalloproteinases (MMPs). RESULTS: HMGB1 at concentrations > 1 ng/mL significantly stimulated HSC growth as revealed by proliferation and BrdU assays. alpha-SMA gene and protein expression were significantly up-regulated by HMGB1, whereas the MMP-2, but not MMP-9, activity was suppressed by HMGB1 treatment. CONCLUSION: Our data suggested that HMGB1 protein, once released during the rejection phase of OLT, activated HSCs and exhibited profibrogenic effects on liver grafts either by increasing the HSC population and extracellular matrix content in liver grafts, or by transforming HSCs into myofibroblasts. Neutralization with anti-HMGB1 antibody was suggested to be a therapeutic modality applicable to prevent fibrogenesis in post-OLT liver grafts.


Subject(s)
Actins/genetics , HMGB1 Protein/pharmacology , Liver/physiology , Actins/drug effects , Animals , Cell Division/drug effects , Cells, Cultured , Gelatin/metabolism , Liver/cytology , Liver/drug effects , Liver Transplantation/pathology , Liver Transplantation/physiology , Matrix Metalloproteinase 2/drug effects , Matrix Metalloproteinase 2/metabolism , Matrix Metalloproteinase 9/drug effects , Matrix Metalloproteinase 9/metabolism , Rats , Reverse Transcriptase Polymerase Chain Reaction
5.
Mem Inst Oswaldo Cruz ; 103(2): 214-5, 2008 Mar.
Article in English | MEDLINE | ID: mdl-18425277

ABSTRACT

The effect of relative humidity (43%, 75%, 86% and > 98%) on Aedes aegypti eggs treated with Metarhizium anisopliae or water only was tested for up to a six months exposure at 25 degrees C. Survival of larvae inside eggs was clearly affected by the lowest humidity (43%) tested, and eclosion diminished at all humidities after increasing periods of exposure. M. anisopliae showed to have a strong ovicidal activity only at humidity close to saturation. No difference of activity was found between conidia and hyphal bodies tested. This fungus affected larvae inside eggs and has potential as a control agent of this important vector in breeding sites with high moisture.


Subject(s)
Aedes/microbiology , Humidity , Hypocreales/physiology , Insect Vectors/microbiology , Animals , Larva/microbiology , Ovum/microbiology , Pest Control, Biological , Time Factors
6.
Mem. Inst. Oswaldo Cruz ; 103(2): 214-215, Mar. 2008. graf
Article in English | LILACS | ID: lil-480630

ABSTRACT

The effect of relative humidity (43 percent, 75 percent, 86 percent and > 98 percent) on Aedes aegypti eggs treated with Metarhizium anisopliae or water only was tested for up to a six months exposure at 25ºC. Survival of larvae inside eggs was clearly affected by the lowest humidity (43 percent) tested, and eclosion diminished at all humidities after increasing periods of exposure. M. anisopliae showed to have a strong ovicidal activity only at humidity close to saturation. No difference of activity was found between conidia and hyphal bodies tested. This fungus affected larvae inside eggs and has potential as a control agent of this important vector in breeding sites with high moisture.


Subject(s)
Animals , Aedes/microbiology , Humidity , Hypocreales/physiology , Insect Vectors/microbiology , Larva/microbiology , Ovum/microbiology , Pest Control, Biological , Time Factors
7.
J Med Entomol ; 44(5): 799-804, 2007 Sep.
Article in English | MEDLINE | ID: mdl-17915511

ABSTRACT

The ovicidal activity of 21 hyphomycete fungi species against Aedes aegypti (L.) (Diptera: Culicidae) was tested. Fungi with ovicidal activity developed on high numbers of eggs (> or =70%) during 25 d of exposure. A clear ovicidal activity with low values of hatch (1.3-40%) was observed after 25 d of incubation with Isaria farinosa (Holm: Fries) Fries, Paecilomyces carneus (Duché & Heim) Brown & Smith, Paecilomyces marquandii (Massee) Hughes, Isaria fumosorosea (Wize), Metarhizium anisopliae (Metschnikoff) Sorokin, Penicillium sp., Paecilomyces lilacinus (Thom) Samson, Beauveria bassiana (Balsamo) Vuillemin, and Evlachovaea kintrischica Borisov & Tarasov. More than 63% of eggs hatched after 25-d exposures to 11 other fungi species deemed as ineffective. These are the first results to show the effects of entomopathogenic fungi against eggs of Ae. aegypti, and they suggest their potential as control agents of this vector.


Subject(s)
Aedes/microbiology , Mitosporic Fungi/pathogenicity , Animals , Female , Fungi/pathogenicity , Larva/microbiology , Mosquito Control/methods , Ovum/microbiology , Pest Control, Biological/methods , Time Factors , Water
8.
Histol Histopathol ; 18(3): 715-26, 2003 07.
Article in English | MEDLINE | ID: mdl-12792883

ABSTRACT

Endostatin, a proteolytic fragment of collagen XVIII, is a potent inhibitor of angiogenesis and suppresses neovascularization and tumor growth. However, the inhibitory mechanism of endostatin in human endothelial cells has not been characterized yet. Electron microscopic analysis revealed that endostatin induced formation of numerous autophagic vacuoles in endothelial in 6 to 24 h after treatment. Moreover, there was only a 2- to 3-fold increase in intracellular reactive oxygen species after endostatin treatment. Endostatin-induced cell death was not prevented by antioxidants (vitamin C, vitamin E, or propyl gallate) or caspase inhibitors, suggesting that the increase of oxidative stress or the activation of caspases may not be the crucial factors in the anti-angiogenic mechanism of endostatin. However, the cytotoxicity of endostatin was significantly reduced by 3-methyladenine (a specific inhibitor of autophagy) and serine and cysteine lysosomal protease inhibitors (leupeptin and aprotinin). Taken together, these results suggest that in human endothelial cells: (1) endostatin predominantly causes autophagic, rather than apoptotic, cell death, (2) endostatin-induced autophagic cell death occurs in the absence of caspase activation and through an oxidative-independent pathway, and (3) endostatin-induced "autophagic cell death" or "type 2 physiological cell death" is regulated by serine and cysteine lysosomal proteases.


Subject(s)
Adenine/analogs & derivatives , Endostatins/pharmacology , Endothelial Cells/pathology , Acridine Orange/pharmacology , Adenine/pharmacology , Animals , Antineoplastic Agents/pharmacology , Apoptosis , Aprotinin/pharmacology , Blotting, Western , CHO Cells , Caspases/metabolism , Cell Death , Cells, Cultured , Cloning, Molecular , Cricetinae , Cysteine/chemistry , Cysteine Endopeptidases/metabolism , Dose-Response Relationship, Drug , Endostatins/metabolism , Endothelial Cells/cytology , Endothelium, Vascular/cytology , Enzyme Activation , Flow Cytometry , Glutathione Transferase/metabolism , Humans , Immunohistochemistry , Leupeptins/pharmacology , Lysosomes/enzymology , Microscopy, Electron , Microscopy, Phase-Contrast , Oxidative Stress , Reactive Oxygen Species , Recombinant Proteins/metabolism , Serine/chemistry , Time Factors
9.
Radiat Res ; 155(1 Pt 2): 201-207, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11121235

ABSTRACT

Two types of human breast epithelial cells (HBEC) have been characterized. In contrast to Type II HBEC, which express basal epithelial cell phenotypes, Type I HBEC are deficient in gap junctional intercellular communication and are capable of anchorage-independent growth and of expressing luminal epithelial cell markers, estrogen receptors, and stem cell characteristics (i.e. the ability to differentiate into other cell types and to form budding/ductal organoids on Matrigel). A comparative study of these two types of cells has revealed a high susceptibility of Type I HBEC to immortalization by SV40 large T antigen, although both types of cells are equally capable of acquiring an extended life span (bypassing senescence) after transfection with SV40. The immortalization was accompanied by elevation of a low level of telomerase activity in the parental cells after mid-passage ( approximately 60 cumulative population doubling levels). Thus HBEC do have a low level of telomerase activity, and Type I HBEC with stem cell characteristics are more susceptible to telomerase activation and immortalization, a mechanism which might qualify them as target cells for breast carcinogenesis. The immortalized Type I HBEC can be converted to highly tumorigenic cells by further treatment with X rays (2 Gy x 2) and transfection with a mutated ERBB2 (also known as NEU) oncogene, resulting in the expression of p185(ERBB2) which is tyrosine phosphorylated.


Subject(s)
Breast/cytology , Cell Transformation, Neoplastic/pathology , Stem Cells/cytology , Animals , Breast/enzymology , Breast Neoplasms/enzymology , Breast Neoplasms/genetics , Breast Neoplasms/pathology , Cell Transformation, Neoplastic/genetics , Cell Transformation, Neoplastic/metabolism , Epithelial Cells/cytology , Epithelial Cells/enzymology , Humans , Stem Cells/enzymology , Telomerase/metabolism
10.
Dev Biol ; 214(2): 258-76, 1999 Oct 15.
Article in English | MEDLINE | ID: mdl-10525333

ABSTRACT

Sensory afferents in the leech are labeled with both constitutive and developmentally regulated glycosylations (markers) of their cell adhesion molecules (CAMs). Their constitutive mannose marker, recognized by Lan3-2 monoclonal antibody (mAb), mediates the formation of their diffuse central arbors. We show that, at the ultrastructural level, these arbors consist of large, loosely organized axons rich with filopodia and synaptic vesicles. Perturbing the mannose-specific adhesion of this first targeting step leads to a gain in cell-cell contact but a loss of filopodia and synaptic vesicles. During the second targeting step, galactose markers divide afferents into different subsets. We focus on the subset labeled by the marker recognized by Laz2-369 mAb. Initially, the galactose marker appears where afferents contact central neurons. Subsequently it spreads proximally and distally, covering the entire afferent surface. Afferents now gain cell-cell contact, with central neurons and self-similar afferents, but lose filopodia and synaptic vesicles. Extant synaptic vesicles prevail where afferents are apposed to central neurons. These neurons develop postsynaptic densities and en passant synapses are forming. Perturbing the galactose-specific adhesion of this second targeting step causes a loss of cell-cell contact but a gain in filopodia and synaptic vesicles, essentially returning afferents to the first targeting step. The transformation of afferent growth, progressing from mannose- to galactose-specific adhesion, is consistent with a change from cell-matrix to cell-cell adhesion. By performing opposing functions in a temporal sequence, constitutive and developmentally regulated glycosylations of CAMs collaborate in the synaptogenesis of afferents and the consolidation of self-similar afferents.


Subject(s)
Cell Adhesion Molecules/physiology , Cell Communication , Gene Expression Regulation, Developmental , Leeches/embryology , Leeches/physiology , Synaptic Vesicles/physiology , Age Factors , Animals , Antibodies, Monoclonal , Biomarkers , Central Nervous System/physiology , Central Nervous System/ultrastructure , Galactose/pharmacology , Galactose/physiology , Ganglia, Invertebrate/drug effects , Ganglia, Invertebrate/physiology , Glycosylation , Leeches/ultrastructure , Mannose/pharmacology , Mannose/physiology , Models, Anatomic , Models, Biological , Neurons, Afferent/ultrastructure , Pseudopodia/drug effects , Synaptic Vesicles/ultrastructure
11.
Dev Biol ; 201(2): 154-66, 1998 Sep 15.
Article in English | MEDLINE | ID: mdl-9740656

ABSTRACT

The developmental role of carbohydrate markers in the genesis of neuronal networks was studied using leech sensory afferents as a model. Leech sensory afferents express a mannose-containing epitope on their cell surface that is recognized by monoclonal antibody Lan3-2. Previously, the elaboration of sensory arbors in the synaptic neuropil of CNS ganglia was experimentally shown to depend on this mannose marker. Sensory arbors were abolished by perturbing sensory afferents in the intact nervous system with Lan3-2 Fab fragments, a glycosidase, or mannose-BSA. To understand the cytological mechanisms underlying mannose-specific recognition for synaptogenesis, we have now studied the effects of antibody perturbation at the ultrastructural level in the sensory afferent target region. A characteristic signature of a normal sensory afferent is its profuse collateral branching, which, with ongoing development, is replaced by a single widened process, the sensory trunk, which possesses numerous synaptic vesicle clusters. The inhibition of mannose-specific recognition leads to a rapid, major reorganization of different stages of sensory afferent growth. Collateral branches at the distal growing region are reduced three- to fourfold. The pruned axons grow at an accelerated rate. Developmentally older sensory trunks experience a threefold reduction in synaptic vesicle clusters. These responses suggest that depriving sensory afferents of mannose-specific recognition aborts their synaptogenesis and causes them to resume behavior typical of tracking through axonal tracts. The current findings also suggest that the mannose marker, by promoting both collateral branching andthe proliferation of synaptic vesicle clusters, plays a critical role in two stages of sensory afferent synaptogenesis.


Subject(s)
Leeches/physiology , Mannose/physiology , Neurons, Afferent/ultrastructure , Synaptic Vesicles/physiology , Animals , Biomarkers/chemistry , Ganglia, Invertebrate/physiology , Immunoglobulin Fab Fragments/pharmacology , Immunohistochemistry , Leeches/embryology , Microscopy, Electron , Models, Biological
12.
Proc Natl Acad Sci U S A ; 95(5): 2592-6, 1998 Mar 03.
Article in English | MEDLINE | ID: mdl-9482931

ABSTRACT

The neural cell adhesion molecule (N-CAM) inhibits astrocyte proliferation in vitro and in vivo, and this effect is partially reversed by the glucocorticoid antagonist RU-486. The present studies have tested the hypothesis that N-CAM-mediated inhibition of astrocyte proliferation is caused by homophilic binding and involves the activation of glucocorticoid receptors. It was observed that all N-CAM Ig domains inhibited astrocyte proliferation in parallel with their ability to influence N-CAM binding. The proliferation of other N-CAM-expressing cells also was inhibited by the addition of N-CAM. In contrast, the proliferation of astrocytes from knockout mice lacking N-CAM was not inhibited by added N-CAM. These findings support the hypothesis that it is binding of soluble N-CAM to N-CAM on the astrocyte surface that leads to decreased proliferation. Signaling pathways stimulated by growth factors include activation of mitogen-activated protein (MAP) kinase. Addition of N-CAM inhibited MAP kinase activity induced by basic fibroblast growth factor in astrocytes. In accord with previous findings that RU-486 could partially prevent the proliferative effects of N-CAM, inhibition of MAP kinase activity by N-CAM was reversed by RU-486. The ability of N-CAM to inhibit astrocyte proliferation was unaffected, however, by agents that block the ability of N-CAM to promote neurite outgrowth. Together, these findings indicate that homophilic N-CAM binding leads to inhibition of astrocyte proliferation via a pathway involving the glucocorticoid receptor and that the ability of N-CAM to influence astrocyte proliferation and neurite outgrowth involves different signal pathways.


Subject(s)
Astrocytes/drug effects , Neural Cell Adhesion Molecules/pharmacology , Signal Transduction/physiology , Animals , Animals, Newborn , Astrocytes/cytology , Astrocytes/physiology , Cell Division/drug effects , DNA/biosynthesis , DNA/drug effects , Fibroblast Growth Factor 2/pharmacology , Glioma , Mice , Mice, Knockout , Neural Cell Adhesion Molecules/biosynthesis , Neural Cell Adhesion Molecules/genetics , Neuroblastoma , Peptide Fragments/pharmacology , Prosencephalon/cytology , Rats , Recombinant Proteins/biosynthesis , Recombinant Proteins/pharmacology , Tumor Cells, Cultured
13.
Proc Natl Acad Sci U S A ; 94(6): 2687-92, 1997 Mar 18.
Article in English | MEDLINE | ID: mdl-9122257

ABSTRACT

In earlier studies, the neural cell adhesion molecule, N-CAM, was found to inhibit the proliferation of rat astrocytes both in vitro and in vivo. To identify the gene targets involved, we used subtractive hybridization to examine changes in gene expression that occur after astrocytes are exposed to N-CAM in vitro. While the mRNA levels for N-CAM decreased after such treatment, the levels of mRNAs for glutamine synthetase and calreticulin increased. Since glutamine synthetase and calreticulin are known to be involved in glucocorticoid receptor pathways, we tested a number of steroids for their effects on astrocyte proliferation. Dexamethasone, corticosterone, and aldosterone were all found to inhibit rat cortical astrocyte proliferation in culture in a dose-dependent manner. RU-486, a potent glucocorticoid antagonist, reversed the inhibitory effects of dexamethasone. These observations prompted the hypothesis that the inhibition of proliferation by N-CAM might be mediated through the glucocorticoid receptor pathway. Consistent with this hypothesis, the inhibition of astrocyte proliferation by N-CAM was reversed in part by a number of glucocorticoid antagonists, including RU-486, dehydroepiandrosterone, and progesterone. In transfection experiments with cultured astrocytes, N-CAM treatment increased the expression of a luciferase reporter gene under the control of a minimal promoter linked to a glucocorticoid response element. The enhanced activity of this construct stimulated by N-CAM was abolished in the presence of RU-486. The combined data suggest that astrocyte proliferation is in part regulated by alterations in glucocorticoid receptor pathways.


Subject(s)
Astrocytes/cytology , Astrocytes/physiology , Glucocorticoids/pharmacology , Neural Cell Adhesion Molecules/physiology , Receptors, Glucocorticoid/physiology , Aldosterone/pharmacology , Animals , Animals, Newborn , Astrocytes/drug effects , Cell Division/drug effects , Cells, Cultured , Corticosterone/pharmacology , Dehydroepiandrosterone/pharmacology , Dexamethasone/pharmacology , Kinetics , Luciferases/biosynthesis , Mifepristone/pharmacology , Neural Cell Adhesion Molecules/biosynthesis , Progesterone/pharmacology , Prosencephalon/cytology , Prosencephalon/physiology , Rats , Recombinant Fusion Proteins/biosynthesis , Transfection
14.
J Comp Neurol ; 371(2): 235-48, 1996 Jul 22.
Article in English | MEDLINE | ID: mdl-8835729

ABSTRACT

We characterized a subset of leech sensory afferents, the photoreceptors, in terms of their molecular composition, anatomical distribution, and candidate postsynaptic partners. For reagents, we used an antiserum generated against purified LL35, a 35 kD leech lactose-binding protein (galectin); monoclonal antibody (mAb) Lan3-2, which is specific for a mannose-containing epitope common to the full set of sensory afferents; and dye injections. Photoreceptors differ from other types of sensory afferents by their abundant expression of galectin. However, photoreceptors share in common with other sensory modalities the mannose-containing epitope recognized by mAb Lan3-2. Photoreceptors from a given segment project their axons directly into the CNS ganglion innervating the same segment. They assemble in a target region, the optic neuropil, which is separate from the target regions of other sensory modalities. They also extend their axons as an optic tract into the connective to innervate optic neuropils of other CNS ganglia, thereby providing extensive intersegmental innervation for the 33 CNS ganglia comprising the leech nerve cord. Because of its intimate contact with the optic neuropil, a central neuron, the AP effector cell, is a strong candidate second order visual neuron. In confocal images, the AP cell projects its primary axon for about 100 microns alongside the optic neuropil. In electron micrographs, spines emanating from the axon of the AP cell make contact with vesicle laden nerve terminals of photoreceptors. Leech photoreceptors and their second order visual neurons represent a simple visual system for studying the mechanisms of axonal targeting.


Subject(s)
Axons/chemistry , Dendrites/chemistry , Lectins/analysis , Neurons, Afferent/ultrastructure , Optic Nerve/chemistry , Photoreceptor Cells, Invertebrate/chemistry , Animals , Central Nervous System/anatomy & histology , Ganglia, Invertebrate/ultrastructure , Leeches/anatomy & histology , Leeches/metabolism , Models, Neurological , Neuroglia/chemistry , Optic Nerve/ultrastructure , Peripheral Nervous System/anatomy & histology , Synapses/ultrastructure
15.
Proc Natl Acad Sci U S A ; 92(19): 8695-9, 1995 Sep 12.
Article in English | MEDLINE | ID: mdl-7567999

ABSTRACT

Fatty acid synthase (FAS; EC 2.3.1.85) was purified to near homogeneity from a human hepatoma cell line, HepG2. The HepG2 FAS has a specific activity of 600 nmol of NADPH oxidized per min per mg, which is about half that of chicken liver FAS. All the partial activities of human FAS are comparable to those of other animal FASs, except for the beta-ketoacyl synthase, whose significantly lower activity is attributable to the low 4'-phosphopantetheine content of HepG2 FAS. We cloned the human brain FAS cDNA. The cDNA sequence has an open reading frame of 7512 bp that encodes 2504 amino acids (M(r), 272,516). The amino acid sequence of the human FAS has 79% and 63% identity, respectively, with the sequences of the rat and chicken enzymes. Northern analysis revealed that human FAS mRNA was about 9.3 kb in size and that its level varied among human tissues, with brain, lung, and liver tissues showing prominent expression. The nucleotide sequence of a segment of the HepG2 FAS cDNA (bases 2327-3964) was identical to that of the cDNA from normal human liver and brain tissues, except for a 53-bp sequence (bases 3892-3944) that does not alter the reading frame. This altered sequence is also present in HepG2 genomic DNA. The origin and significance of this sequence variance in the HepG2 FAS gene are unclear, but the variance apparently does not contribute to the lower activity of HepG2 FAS.


Subject(s)
Fatty Acid Synthases/genetics , Amino Acid Sequence , Animals , Base Sequence , Brain/enzymology , Carcinoma, Hepatocellular/enzymology , Chickens , Cloning, Molecular , DNA, Complementary/genetics , Fatty Acid Synthases/isolation & purification , Fatty Acid Synthases/metabolism , Humans , Liver Neoplasms/enzymology , Molecular Sequence Data , Pantetheine/analogs & derivatives , Pantetheine/analysis , Rats , Restriction Mapping , Sequence Analysis, DNA , Sequence Homology, Amino Acid , Species Specificity , Tissue Distribution , Tumor Cells, Cultured
16.
Proc Natl Acad Sci U S A ; 90(5): 1852-6, 1993 Mar 01.
Article in English | MEDLINE | ID: mdl-8446599

ABSTRACT

Thioesterase II (TE II), present in specialized tissues, catalyzes the chain termination and release of medium-chain fatty acids from fatty acid synthase [FAS; acyl-CoA:malonyl-CoA C-acyltransferase (decarboxylating, oxoacyl- and enoyl-reducing and thioester-hydrolyzing), EC 2.3.1.85]. We have expressed rat mammary gland TE II in Escherichia coli and created several site-directed mutants. Replacing both Ser101 and His237 with Ala yielded inactive proteins, suggesting that these residues are part of the catalytic triad as in FAS thioesterase (TE I). Mutating the conserved Asp236 or modifying it with Woodward's reagent K caused partial loss (40%) of TE II activity and reduced reactivity of Ser101 and His237 toward their specific inhibitors, phenylmethylsulfonyl fluoride and diethylpyrocarbonate, respectively. These results suggested that Asp236 enhances, but is not essential for, the reactivity of Ser101 and His237. Mutation analyses revealed that, at the C terminus, Leu262 is critical for TE II to interact with FAS. Hydrophobic interactions seem to play a role, since the interaction of TE II with FAS is enhanced by polyethylene glycol but reduced by salt. The Ser101 and His237 mutants and a synthetic C-terminal decapeptide did not compete in the interaction. These results suggest that a TE II-acyl FAS complex forms first, which then is stabilized by the interaction of the hydrophobic C terminus of TE II with FAS, leading ultimately to hydrolysis and release of fatty acid.


Subject(s)
Fatty Acid Synthases/chemistry , Fatty Acid Synthases/metabolism , Thiolester Hydrolases/chemistry , Amino Acid Sequence , Animals , Base Sequence , Binding Sites , Cloning, Molecular , Diethyl Pyrocarbonate/pharmacology , Fatty Acid Synthases/antagonists & inhibitors , Molecular Sequence Data , Mutagenesis, Site-Directed , Palmitoyl Coenzyme A/metabolism , Phenylmethylsulfonyl Fluoride/pharmacology , Rats , Recombinant Proteins/metabolism , Structure-Activity Relationship , Thiolester Hydrolases/antagonists & inhibitors , Thiolester Hydrolases/metabolism
17.
Life Sci ; 51(11): 839-45, 1992.
Article in English | MEDLINE | ID: mdl-1522746

ABSTRACT

The effects of ketanserin (Ket), a serotonin (5-HT2) receptor antagonist, on DOI- and mCPP-, two 5-HT agonists, and TRH-induced PRL secretion were studied. Adult female Sprague-Dawley rats ovariectomized for two weeks and treated with a long-acting estrogen, polyestradiol phosphate for one week were used. Drug administration and serial blood sampling were accomplished through indwelling intraatrial catheters which were implanted two days before the experiment. Both DOI (0.5 mg/kg BW) and mCPP (1 mg/kg BW) stimulated prolactin secretion within 10 min after iv injection and the effects were diminished by 30 min. In animals pretreated with Ket (5 mg/kg BW, sc), the effect of DOI was blocked, while that of mCPP was augmented. Co-administration of Ket (1 mg/kg BW, iv) with DOI or mCPP produced similar effect. Pretreatment with Ket, similar to sulpiride (Sulp), a dopamine antagonist, potentiated the TRH-induced prolactin secretion. Co-administration of Ket and Sulp further potentiated the TRH action. It is concluded that Ket not only acts as a 5-HT2 receptor antagonist that blocks the action of DOI, but may also act on dopamine receptor(s) with lower sensitivity to Sulp.


Subject(s)
Amphetamines/pharmacology , Estrogens/pharmacology , Ketanserin/pharmacology , Piperazines/pharmacology , Prolactin/metabolism , Thyrotropin-Releasing Hormone/pharmacology , Amphetamines/antagonists & inhibitors , Animals , Dopamine Antagonists , Drug Synergism , Female , Rats , Rats, Inbred Strains , Serotonin Antagonists/pharmacology , Sulpiride/pharmacology , Time Factors
18.
Chin J Physiol ; 33(4): 345-52, 1990.
Article in English | MEDLINE | ID: mdl-2097103

ABSTRACT

The possible involvement of the dopaminergic system in the serotonin (5-HT)-stimulated prolactin (PRL) secretion was tested in this study. Adult female rats were ovariectomized for two weeks and treated with estrogen (polyestradiol phosphate, 0.1 mg/rat, sc) for 6 days before use. They either received pretreatment with alpha-methyl-p-tyrosine (250 mg/kg BW, ip), a dopamine (DA) synthesis inhibitor, or two DA antagonists, domperidone and haloperidol (0.1 mg/kg BW, iv) before receiving 5-HT (1 mg/kg BW, iv) or quipazine (1 mg/kg BW, iv), a 5-HT agonist. Blockade of DA synthesis or antagonism of DA action invariably induced elevated plasma PRL levels. 5-HT or quipazine, however, could still induce significant PRL secretion on top of the increased PRL levels. Minor difference was found between the action of domperidone and that of haloperidol. In conclusion, the dopaminergic system may not be involved in the action of 5-HT to stimulate PRL secretion.


Subject(s)
Prolactin/metabolism , Receptors, Dopamine/physiology , Serotonin/pharmacology , Animals , Domperidone/pharmacology , Female , Haloperidol/pharmacology , Methyltyrosines/pharmacology , Rats , Rats, Inbred Strains , alpha-Methyltyrosine
19.
Appl Opt ; 17(18): 2991-3002, 1978 Sep 15.
Article in English | MEDLINE | ID: mdl-20203909

ABSTRACT

This paper analyzes the systematic errors in Hadamard transform optical instruments caused by moving masks, incorrect mask alignment, faulty mask fabrication, missing data, diffraction, etc. and describes techniques for reducing or eliminating these errors. In a great many cases the behavior of the instrument can be characterized by a single matrix equation of the form eta = TWa + e, where the components of eta are the measurements, T is a matrix characterizing the instrument, W specifies the mask configurations, a is a vector containing the unknown spectral intensities, and the components of e are small random errors.

20.
Appl Opt ; 16(12): 3071-2, 1977 Dec 01.
Article in English | MEDLINE | ID: mdl-20174297
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