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1.
Front Public Health ; 12: 1294340, 2024.
Article in English | MEDLINE | ID: mdl-38655511

ABSTRACT

Introduction: Children and youth with disabilities and special healthcare needs, and their families, have been uniquely affected by the COVID-19 pandemic. However, the voices of children themselves are still not well represented in the existing literature. Methods: This qualitative descriptive study used a combination of visual methods and interviews to learn about the experiences of Canadian children with disabilities (n=18) and their parents (n=14) during the COVID pandemic and into the post-pandemic period. Data collection was carried out between January and July 2023. The aim was to identify the supports and services children and families need at present and moving forward. Results: Families' pandemic experiences were complex and nuanced. For many, the pandemic complicated and disrupted everyday activities and supports. These disruptions were largely buffered by parents. However, some families also identified unexpected benefits. Key themes pertaining to present and future needs included the need for services that are flexible; consistent; conducive to relationship-building; comprehensive; coordinated across sectors; and designed to support the needs of the whole family. Discussion: Implications for policy and practice are outlined.


Subject(s)
COVID-19 , Disabled Children , Parents , Qualitative Research , Humans , COVID-19/epidemiology , Child , Parents/psychology , Canada/epidemiology , Female , Male , Adolescent , Health Services Needs and Demand , SARS-CoV-2 , Adult , Child, Preschool , Social Support , Pandemics
2.
Mar Drugs ; 19(1)2021 Jan 16.
Article in English | MEDLINE | ID: mdl-33467112

ABSTRACT

Chemical investigation of a Red Sea Spongia sp. led to the isolation of four new compounds, i.e., 17-dehydroxysponalactone (1), a carboxylic acid, spongiafuranic acid A (2), one hydroxamic acid, spongiafuranohydroxamic acid A (3), and a furanyl trinorsesterpenoid 16-epi-irciformonin G (4), along with three known metabolites (-)-sponalisolide B (5), 18-nor- 3,17-dihydroxy-spongia-3,13(16),14-trien-2-one (6), and cholesta-7-ene-3ß,5α-diol-6-one (7). The biosynthetic pathway for the molecular skeleton of 1 and related compounds was postulated for the first time. Anti-inflammatory activity of these metabolites to inhibit superoxide anion generation and elastase release in N-formyl-methionyl-leucyl phenylalanine/cytochalasin B (fMLF/CB)-induced human neutrophil cells and cytotoxicity of these compounds toward three cancer cell lines and one human dermal fibroblast cell line were assayed. Compound 1 was found to significantly reduce the superoxide anion generation and elastase release at a concentration of 10 µM, and compound 5 was also found to display strong inhibitory activity against superoxide anion generation at the same concentration. Due to the noncytotoxic activity and the potent inhibitory effect toward the superoxide anion generation and elastase release, 1 and 5 can be considered to be promising anti-inflammatory agents.


Subject(s)
Anti-Inflammatory Agents/metabolism , Diterpenes/metabolism , Porifera/metabolism , Terpenes/metabolism , Animals , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/pharmacology , Cells, Cultured , Diterpenes/chemistry , Diterpenes/pharmacology , Humans , Indian Ocean , Neutrophils/drug effects , Neutrophils/metabolism , Porifera/chemistry , Terpenes/chemistry , Terpenes/pharmacology
3.
Mar Drugs ; 17(8)2019 Aug 07.
Article in English | MEDLINE | ID: mdl-31394844

ABSTRACT

Two new capnosane-based diterpenoids, flaccidenol A (1) and 7-epi-pavidolide D (2), two new cembranoids, flaccidodioxide (3) and flaccidodiol (4), and three known compounds 5 to 7 were characterized from the marine soft coral Klyxum flaccidum, collected off the coast of the island of Pratas. The structures of the new compounds were determined by extensive spectroscopic analyses, including 1D and 2D nuclear magnetic resonance (NMR) spectroscopy, and spectroscopic data comparison with related structures. The rare capnosane diterpenoids were isolated herein from the genus Klyxum for the first time. The cytotoxicity of compounds 1 to 7 against the proliferation of a limited panel of cancer cell lines was assayed. The isolated diterpenoids also exhibited anti-inflammatory activity through suppression of superoxide anion generation and elastase release in the N-formyl-methionyl-leucyl-phenylalanine/cytochalasin B (fMLF/CB)-stimulated human neutrophils. Furthermore, 1 and 7 also exhibited cytotoxicity toward the tested cancer cells, and 7 could effectively inhibit elastase release. It is worth noting that the biological activities of 7 are reported for the first time in this paper.


Subject(s)
Anthozoa/chemistry , Biological Factors/pharmacology , Diterpenes/pharmacology , Animals , Anti-Inflammatory Agents/pharmacology , Cell Line , Cell Line, Tumor , Cell Proliferation/drug effects , Cytochalasin B/pharmacology , Drug Screening Assays, Antitumor/methods , Humans , Magnetic Resonance Spectroscopy/methods , N-Formylmethionine Leucyl-Phenylalanine/metabolism , Neutrophils/drug effects , Neutrophils/metabolism , Pancreatic Elastase/metabolism , Superoxides/metabolism
4.
Mar Drugs ; 17(2)2019 Feb 17.
Article in English | MEDLINE | ID: mdl-30781569

ABSTRACT

Three new eunicellin-derived diterpenoids of briarellin type, briarenones A‒C (1‒3), were isolated from a Formosan gorgonian Briareum violaceum. The chemical structures of the compounds were elucidated on the basis of extensive spectroscopic analyses, including two-dimensional (2D) NMR. The absolute configuration of 1 was further confirmed by a single crystal X-ray diffraction analysis. The in vitro cytotoxic and anti-inflammatory potentialities of the isolated metabolites were tested against the growth of a limited panel of cancer cell lines and against the production of superoxide anions and elastase release in N-formyl-methionyl-leucyl-phenyl-alanine and cytochalasin B (fMLF/CB)-stimulated human neutrophils, respectively.


Subject(s)
Cnidaria/chemistry , Diterpenes/chemistry , Animals , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Antineoplastic Agents/pharmacology , Cell Line, Tumor , Cytochalasins/pharmacology , Diterpenes/isolation & purification , Humans , Magnetic Resonance Spectroscopy , Models, Molecular , Molecular Conformation , Neutrophils/drug effects , Neutrophils/metabolism , Pancreatic Elastase/metabolism , Superoxides/metabolism , X-Ray Diffraction
5.
RSC Adv ; 8(14): 7863-7872, 2018 Feb 14.
Article in English | MEDLINE | ID: mdl-35539133

ABSTRACT

The endophytic fungus Aspergillus aculeatus isolated from leaves of the papaya plant Carica papaya was fermented on solid rice medium, yielding a new l-tryptophan-l-phenyllactic acid conjugate (1) and thirteen known compounds (11, 14-25). In addition, an OSMAC approach was employed by adding eight different sodium or ammonium salts to the rice medium. Addition of 3.5% NaNO3 caused a significant change of the metabolite pattern of the fungus as indicated by HPLC analysis. Subsequent isolation yielded several new substituted l-tryptophan-l-phenyllactic acid conjugates (1-10) in addition to three known compounds (11-13), among which compounds 2-10, 12-13 were not detected in the rice control culture. All structures were unambiguously elucidated by one and two dimensional NMR spectroscopy and by mass spectrometry. The absolute configuration of the new compounds was determined by Marfey's reaction and X-ray single crystal diffraction. Compounds 19-22 showed cytotoxicity against the L5178Y mouse lymphoma cell line with IC50 values of 3.4, 1.4, 7.3 and 23.7 µM, respectively.

6.
Mar Drugs ; 15(11)2017 Nov 14.
Article in English | MEDLINE | ID: mdl-29135916

ABSTRACT

The marine-derived fungus Talaromyces rugulosus isolated from the Mediterranean sponge Axinella cannabina and cultured on solid rice medium yielded seventeen lactone derivatives including five butenolides (1-5), seven (3S)-resorcylide derivatives (6-12), two butenolide-resorcylide dimers (13 and 14), and three dihydroisocoumarins (15-17). Among them, fourteen compounds (1-3, 6-16) are new natural products. The structures of the isolated compounds were elucidated by 1D and 2D NMR (Nuclear Magnetic Resonance) spectroscopy as well as by ESI-HRMS (ElectroSpray Ionization-High Resolution Mass Spectrometry). TDDFT-ECD (Time-Dependent Density Functional Theory-Electronic Circular Dichroism) calculations were performed to determine the absolute configurations of chiral compounds. The butenolide-resorcylide dimers talarodilactones A and B (13 and 14) exhibited potent cytotoxicity against the L5178Y murine lymphoma cell line with IC50 values of 3.9 and 1.3 µM, respectively.


Subject(s)
Lactones/chemistry , Porifera/chemistry , Talaromyces/chemistry , 4-Butyrolactone/analogs & derivatives , 4-Butyrolactone/chemistry , 4-Butyrolactone/pharmacology , Animals , Biological Products/chemistry , Biological Products/pharmacology , Cell Line, Tumor , Circular Dichroism , Lactones/pharmacology , Leukemia L5178/drug therapy , Mice , Nuclear Magnetic Resonance, Biomolecular/methods
7.
J Antibiot (Tokyo) ; 70(6): 726-732, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28270687

ABSTRACT

Using the OSMAC (One Strain MAny Compounds) approach, the fungal endophyte Fusarium tricinctum was cultivated on fruit and vegetable juice-supplemented solid rice media. This led to an up to 80-fold increase in the accumulation of the new natural product fusarielin J (1), as well as to the induction of two new natural products fusarielin K (2) and fusarielin L (3) and the known derivatives fusarielins A (4) and B (5). Compounds 2-5 were not detected when the fungus was grown on rice media lacking either fruit or vegetable juice. The highest increase in the accumulation of compound 1 was observed in the presence of apple and carrot juice, whereas the stimulating effect was weaker for banana juice. Compound 1 exhibited cytotoxicity against the human ovarian cancer cell line A2780, with an IC50 value of 12.5 µM.


Subject(s)
Antineoplastic Agents/isolation & purification , Epoxy Compounds/pharmacology , Fusarium/metabolism , Naphthalenes/pharmacology , Ovarian Neoplasms/drug therapy , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Cell Line, Tumor , Culture Media , Culture Techniques , Epoxy Compounds/chemistry , Epoxy Compounds/isolation & purification , Female , Fruit and Vegetable Juices , Humans , Inhibitory Concentration 50 , Naphthalenes/chemistry , Naphthalenes/isolation & purification , Oryza/microbiology , Ovarian Neoplasms/pathology
8.
J Nat Prod ; 80(1): 169-180, 2017 01 27.
Article in English | MEDLINE | ID: mdl-28075580

ABSTRACT

Fourteen new natural products, namely, 2-[(Z)-styryl]-5-geranylresorcin-1-carboxylic acid (1), amorfrutin D (2), 4-O-demethylamorfrutin D (3), 8-geranyl-3,5,7-trihydroxyflavanone (4), 8-geranyl-5,7,3'-trihydroxy-4'-methoxyisoflavone (5), 6-geranyl-5,7,3'-trihydroxy-4'-methoxyisoflavone (6), 8-geranyl-7,3'-dihydroxy-4'-methoxyisoflavone (7), 3-O-demethyldalbinol (8), 6a,12a-dehydro-3-O-demethylamorphigenin (9), (6aR,12aR,5'R)-amorphigenin (10), amorphispironones B and C (11 and 12), resokaempferol 3-O-ß-d-glucopyranosyl-(1→2)-ß-d-glucopyranoside-7-O-α-l-rhamnopyranoside (13), and daidzein 7-O-ß-d-glucopyranosyl-(1→2)-ß-d-glucopyranoside (14), together with 40 known compounds, were isolated from the fruits of Amorpha fruticosa. The structures of the new compounds were elucidated by 1D and 2D NMR spectroscopic analysis as well as from the mass spectrometry data. ECD calculations were performed to determine the absolute configurations of 11 and 15. Compounds 1, 4-6, and 16-23 showed potent to moderate antibacterial activities against several Gram-positive bacteria with MIC values ranging from 3.1 to 100 µM. In addition, compounds 11 and 24-33 were significantly cytotoxic against the L5178Y mouse lymphoma cell line and exhibited IC50 values from 0.2 to 10.2 µM.


Subject(s)
Anti-Bacterial Agents/isolation & purification , Fabaceae/chemistry , Fruit/chemistry , Isoflavones/isolation & purification , Lymphoma/drug therapy , Phenols/chemistry , Plant Extracts/isolation & purification , Animals , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Inhibitory Concentration 50 , Isoflavones/chemistry , Isoflavones/pharmacology , Lymphoma/chemistry , Mice , Molecular Structure , Plant Extracts/chemistry , Plant Extracts/pharmacology
9.
Methods Mol Biol ; 1520: 63-83, 2017.
Article in English | MEDLINE | ID: mdl-27873246

ABSTRACT

Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for the structure elucidation of antibiotics in solution. Over the past 30 years there have been numerous publications describing the use of NMR to characterize naturally derived or synthetic antibiotics. A large number of one-dimensional (1D) and two-dimensional (2D) NMR methods are available today and the list continues to expand. In this chapter, we will consider the key NMR experiments that provide useful information for compound structure elucidation.


Subject(s)
Anti-Bacterial Agents/chemistry , Magnetic Resonance Spectroscopy/methods , Carbon-13 Magnetic Resonance Spectroscopy , Peptides, Cyclic/chemistry , Proton Magnetic Resonance Spectroscopy
10.
Phys Rev Lett ; 117(17): 171101, 2016 Oct 21.
Article in English | MEDLINE | ID: mdl-27824449

ABSTRACT

The GRAPES-3 tracking muon telescope in Ooty, India measures muon intensity at high cutoff rigidities (15-24 GV) along nine independent directions covering 2.3 sr. The arrival of a coronal mass ejection on 22 June 2015 18:40 UT had triggered a severe G4-class geomagnetic storm (storm). Starting 19:00 UT, the GRAPES-3 muon telescope recorded a 2 h high-energy (∼20 GeV) burst of galactic cosmic rays (GCRs) that was strongly correlated with a 40 nT surge in the interplanetary magnetic field (IMF). Simulations have shown that a large (17×) compression of the IMF to 680 nT, followed by reconnection with the geomagnetic field (GMF) leading to lower cutoff rigidities could generate this burst. Here, 680 nT represents a short-term change in GMF around Earth, averaged over 7 times its volume. The GCRs, due to lowering of cutoff rigidities, were deflected from Earth's day side by ∼210° in longitude, offering a natural explanation of its night-time detection by the GRAPES-3. The simultaneous occurrence of the burst in all nine directions suggests its origin close to Earth. It also indicates a transient weakening of Earth's magnetic shield, and may hold clues for a better understanding of future superstorms that could cripple modern technological infrastructure on Earth, and endanger the lives of the astronauts in space.

11.
J Nat Prod ; 79(4): 914-22, 2016 Apr 22.
Article in English | MEDLINE | ID: mdl-27070198

ABSTRACT

The endophytic fungus Aspergillus austroafricanus isolated from leaves of the aquatic plant Eichhornia crassipes was fermented axenically on solid rice medium as well as in mixed cultures with Bacillus subtilis or with Streptomyces lividans. Chromatographic analysis of EtOAc extract of axenic cultures afforded two new metabolites, namely, the xanthone dimer austradixanthone (1) and the sesquiterpene (+)-austrosene (2), along with five known compounds (3-7). Austradixanthone (1) represents the first highly oxygenated heterodimeric xanthone derivative. When A. austroafricanus was grown in mixed cultures with B. subtilis or with S. lividans, several diphenyl ethers (8-11) including the new austramide (8) were induced up to 29-fold. The structures of new compounds were unambiguously elucidated using 1D- and 2D-NMR spectroscopy, HRESIMS, and chemical derivatization. Compound 7 exhibited weak cytotoxicity against the murine lymphoma L5178Y cell line (EC50 is 12.6 µM). In addition, compounds 9 and 10, which were enhanced in mixed fungal/bacterial cultures, proved to be active against Staphylococcus aureus (ATCC 700699) with minimal inhibitory concentrations (MICs) of 25 µM each (6.6 µg/mL), whereas compound 11 revealed moderate antibacterial activity against B. subtilis 168 trpC2 with an MIC value of 34.8 µM (8 µg/mL).


Subject(s)
Aspergillus/chemistry , Sesquiterpenes/isolation & purification , Xanthones/isolation & purification , Animals , Anti-Bacterial Agents/chemistry , Bacillus subtilis/drug effects , Mice , Microbial Sensitivity Tests , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Sesquiterpenes/chemistry , Staphylococcus aureus/drug effects , Xanthones/chemistry
12.
J Agric Food Chem ; 64(16): 3127-32, 2016 Apr 27.
Article in English | MEDLINE | ID: mdl-27050289

ABSTRACT

Chemical investigation of the endophytic fungus Fusarium oxysporum isolated from fruits of Drepanocarpus lunatus afforded eight new fusaric acid derivatives, fusaricates A-G, 1-7, and 10-hydroxy-11-chlorofusaric acid, 8, along with four known compounds. Their structures were elucidated by one- and two-dimensional NMR as well as MS data and by comparison with the literature. The absolute configurations of fusaricates C-E, 3-5, were determined using chiral GC-MS. Fusaricates A-G, 1-7, represent the first examples of fusaric acid linked to a polyalcohol moiety via an ester bond. All isolated fusaric acid derivatives 1-8 showed significant phytotoxicity to leaves of barley.


Subject(s)
Fusaric Acid/toxicity , Fusarium/chemistry , Hordeum/microbiology , Plant Diseases/microbiology , Plant Leaves/drug effects , Plant Leaves/microbiology , Spectrometry, Mass, Electrospray Ionization
13.
Am J Physiol Endocrinol Metab ; 306(4): E443-56, 2014 Feb 15.
Article in English | MEDLINE | ID: mdl-24368670

ABSTRACT

In utero exposure to nicotine is associated with increased risk of numerous adverse fetal and neonatal outcomes, which suggests that it acts directly to affect placental development and the establishment of the fetomaternal circulation (FC). This study used both in vivo [Wistar rats treated with 1 mg/kg nicotine from 2 wk prior to mating until gestational day (GD) 15] and in vitro (RCHO-1 cell line; treated with 10(-9) to 10(-3)M nicotine) models to examine the effects of nicotine on these pathways. At GD 15, control and treated placentas were examined for the impact of nicotine on 1) trophoblast invasion, proliferation, and degree of hypoxia, 2) labyrinth vascularization, 3) expression of key genes of placental development, and 4) expression of placental angiogenic factors. The RCHO-1 cell line was used to determine the direct effects of nicotine on trophoblast differentiation. Our in vivo experiments show that nicotine inhibits trophoblast interstitial invasion, increases placental hypoxia, downregulates labyrinth vascularization as well as key transcription factors Hand1 and GCM1, and decreases local and circulating EG-VEGF, a key placental angiogenic factor. The in vitro experiments confirmed the inhibitory effects of nicotine on the trophoblast migration, invasion, and differentiation processes and demonstrated that those effects are most likely due to a dysregulation in the expression of nicotine receptors and a decrease in MMP9 activity. Taken together, these data suggest that adverse effects of maternal smoking on pregnancy outcome are due in part to direct and endocrine effects of nicotine on the main processes of placental development and establishment of FC.


Subject(s)
Nicotine/pharmacology , Placenta/drug effects , Placentation/drug effects , Trophoblasts/drug effects , Animals , Basic Helix-Loop-Helix Transcription Factors/metabolism , Cell Line , Cell Proliferation/drug effects , Female , Placenta/metabolism , Pregnancy , Rats , Rats, Wistar , Trophoblasts/cytology , Trophoblasts/metabolism , Vascular Endothelial Growth Factor A/metabolism
14.
Nutr Diabetes ; 3: e88, 2013 Sep 16.
Article in English | MEDLINE | ID: mdl-24042701

ABSTRACT

BACKGROUND: Obesity is associated with low-grade systemic inflammation, in part because of secretion of proinflammatory cytokines, resulting into peripheral insulin resistance (IR). Increased oxidative stress is proposed to link adiposity and chronic inflammation. The effects of endurance exercise in modulating these outcomes in insulin-resistant obese adults remain unclear. We investigated the effect of endurance exercise on markers of oxidative damage (4-hydroxy-2-nonenal (4-HNE), protein carbonyls (PCs)) and antioxidant enzymes (superoxide dismutase (SOD), catalase) in skeletal muscle; urinary markers of oxidative stress (8-hydroxy-2-deoxyguanosine (8-OHdG), 8-isoprostane); and plasma cytokines (C-reactive protein (CRP), interleukin-6 (IL-6), leptin, adiponectin). METHODS: Age- and fitness-matched sedentary obese and lean men (n=9 per group) underwent 3 months of moderate-intensity endurance cycling training with a vastus lateralis biopsy, 24-h urine sample and venous blood samples taken before and after the intervention. RESULTS: Obese subjects had increased levels of oxidative damage: 4-HNE (+37%; P0.03) and PC (+63%; P0.02); evidence of increased adaptive response to oxidative stress because of elevated levels of copper/zinc SOD (Cu/ZnSOD) protein content (+84%; P0.01); increased markers of inflammation: CRP (+737%; P0.0001) and IL-6 (+85%; P0.03), and these correlated with increased markers of obesity; and increased leptin (+262%; P0.0001) with lower adiponectin (-27%; P0.01) levels vs lean controls. Training reduced 4-HNE (-10%; P0.04), PC (-21%; P0.05), 8-isoprostane (-26%; P0.02) and leptin levels (-33%; P0.01); had a tendency to decrease IL-6 levels (-21%; P=0.07) and IR (-17%; P=0.10); and increased manganese SOD (MnSOD) levels (+47%; P0.01). CONCLUSION: Endurance exercise reduced skeletal muscle-specific and systemic oxidative damage while improving IR and cytokine profile associated with obesity, independent of weight loss. Hence, exercise is a useful therapeutic modality to reduce risk factors associated with the pathogenesis of IR in obesity.

15.
Z Naturforsch C J Biosci ; 64(9-10): 637-43, 2009.
Article in English | MEDLINE | ID: mdl-19957430

ABSTRACT

A detailed chemical study of the aerial parts of Tamarix nilotica (Tamaricaceae) from Saudi Arabia led to the isolation of a new pentacyclic triterpenoid, 3-O-trans-caffeoylisomyricadiol, in addition to nine known compounds. The structures of all isolated compounds were unambiguously elucidated by 1D, 2D NMR, and mass spectrometry. In the radical scavenging (DPPH) assay, 3-O-trans-caffeoylisomyricadiol exhibited potent antioxidant activity with an IC50 value of 3.56 microM, while that for quercetin (standard antioxidant) was 5.72 microM.


Subject(s)
Tamaricaceae/chemistry , Triterpenes/isolation & purification , Free Radical Scavengers/chemistry , Free Radical Scavengers/isolation & purification , Free Radical Scavengers/pharmacology , Magnetic Resonance Spectroscopy , Mass Spectrometry , Molecular Structure , Saudi Arabia , Triterpenes/chemistry , Triterpenes/pharmacology
18.
Am J Med Genet ; 106(1): 62-70, 2001.
Article in English | MEDLINE | ID: mdl-11579426

ABSTRACT

Reactive oxygen species (ROS) generated by mitochondria are produced as by-products of normal oxidative metabolism. The fate of these species is governed by a number of factors that vary from tissue to tissue in mammals and may be involved in the pathogenesis of disease. Reactive oxygen species are also invoked as agents that are important in the processes which become active in cells undergoing apoptosis. Integration of knowledge surrounding these different aspects of ROS generation is difficult and reveals considerable gaps in our understanding.


Subject(s)
Apoptosis , Free Radicals/metabolism , Mitochondria/genetics , Oxygen/metabolism , Animals , Carrier Proteins/genetics , Cytochrome c Group/metabolism , Electron Transport/genetics , Genes, p53/genetics , Humans , Membrane Proteins/genetics , Mice , Mitochondria/metabolism , Models, Biological , Reactive Oxygen Species/metabolism , Superoxides/metabolism
19.
Mol Cell Biochem ; 223(1-2): 47-60, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11681721

ABSTRACT

In the present study, we examined the involvement of intracellular ceramide in host pathogen interaction of BALB/c mouse peritoneal macrophages infected with the obligate intracellular protozoan, Leishmania donovani. Our findings indicate that the level of intracellular ceramide was enhanced as a result of the in vitro infection. While the elevated ceramide was largely due to de novo synthesis, activation of the sphingomyelinases was also observed. The enhanced ceramide was responsible for the downregulation of classical PKC activity, upregulation of calcium independent atypical PKC-zeta expression and activity of calcium independent PKC. Ceramide also impaired the phosphorylation of MAPK. Evidently, ceramide suppressed the generation of nitric oxide during leishmanial infection and also facilitated the survival of leishmanial parasites in the intramacrophageal milieu. These data present newer insight to the signaling events in leishmania-infected murine macrophages, which might offer ceramide as a new therapeutic target in the future.


Subject(s)
Ceramides/biosynthesis , Fumonisins , Leishmania donovani/physiology , Macrophages, Peritoneal/metabolism , Macrophages, Peritoneal/parasitology , Signal Transduction/physiology , Animals , Antiprotozoal Agents/pharmacology , Carboxylic Acids/pharmacology , Ceramides/pharmacology , Enzyme Inhibitors/pharmacology , Genistein/pharmacology , Interferon-gamma/pharmacology , Lipopolysaccharides/pharmacology , Macrophages, Peritoneal/drug effects , Mice , Mice, Inbred BALB C , Mitogen-Activated Protein Kinases/metabolism , Monensin/pharmacology , Nitric Oxide/metabolism , Protein Kinase C/metabolism , Sphingomyelin Phosphodiesterase/metabolism
20.
Alcohol ; 25(1): 1-8, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11668012

ABSTRACT

The facial features that are characteristic of fetal alcohol syndrome (FAS) are strikingly similar to those seen in pyruvate dehydrogenase (PDH) deficiency. Furthermore, alcohol-induced central nervous system insult results in midline anomalies such as agenesis of the corpus callosum, which has also been described in several metabolic diseases, including PDH deficiency. The purpose of this work was to examine the effect of acetaldehyde on PDH in vitro. The activity of PDH was measured in the presence of acetaldehyde (10 microM-1 mM) by measuring the formation of the reduced form of nicotinamide-adenine dinucleotide at 340 nm. Pyruvate dehydrogenase was separated by using the sodium dodecyl sulfate-polyacrylamide gel electrophoresis technique after incubation with [1,2-(14)C]-acetaldehyde to detect the formation of covalent adducts autoradiographically. The effect of acetaldehyde on the phosphorylation of the complex was also determined autoradiographically after incubating of PDH with (32)P-adenosine triphosphate. The results of this study show that acetaldehyde impairs PDH activity by a mixed inhibition type mechanism (Kic=62.4+/-25.7 microM, Kiu=225+/-68 microM), which is not a result of the formation of covalent adducts with PDH, nor of a stimulation of phosphorylation or inactivation of the complex. Because PDH levels are low throughout development and that the competition between pyruvate and acetaldehyde may be enhanced due to ethanol-induced lowering of ambient pyruvate concentrations, we conclude that impairment of PDH may have a significant effect on the developing fetus.


Subject(s)
Acetaldehyde/pharmacology , Enzyme Inhibitors/pharmacology , Pyruvate Dehydrogenase Complex/antagonists & inhibitors , Animals , Kinetics , Myocardium/enzymology , Phosphorylation/drug effects , Swine
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