falciparum sarcoendoplasmic reticulum: Topics by WorldWideScience.org

Molecular Mechanistic Insights into the Endothelial Receptor Mediated Cytoadherence of Plasmodium falciparum-Infected Erythrocytes

... atp-ase azido compounds biochemical reaction kinetics endoplasmic reticulum

1984-05-02

The binding of polyribosomes to smooth and rough endoplasmic-reticulum membranes (Short Communication)

Cytoadherence or sequestration is essential for the pathogenesis of the most virulent human malaria species, Plasmodium falciparum (P. falciparum). Similar to leukocyte-endothelium...Full Text Available

var gene transcription and PfEMP1 expression in the rosetting and cytoadhesive Plasmodium falciparum clone FCR3S1.2

In vitro the binding of polyribosomes to smooth endoplasmic-reticulum membranes is more sensitive to ionic strength than is the binding to rough endoplasmic-reticulum membranes. Polyribosomes...Full Text Available

1973-04-01

The relationship between the Plasmodium falciparum parasite ratio in childhood and climate estimates of malaria transmission in Kenya

BackgroundThe pathogenicity of Plasmodium falciparum is in part due to the ability of the parasitized red blood cell (pRBC) to adhere to intra-vascular host cell...Full Text Available

The Dynamics of Naturally Acquired Immune Responses to Plasmodium falciparum Sexual Stage Antigens Pfs230 & Pfs48/45 in a Low Endemic Area in Tanzania

BackgroundPlasmodium falciparum morbid and fatal risks are considerably higher in areas supporting parasite prevalence ≥25%, when compared with low transmission...Full Text Available

Sensitivity of Plasmodium falciparum to chloroquine and sulfadoxine/pyrimethamine in Nigerian children.

BackgroundNaturally acquired immune responses against sexual stages of P. falciparum can reduce the transmission of malaria from humans to mosquitoes. These antigens...Full Text Available

Population genetic analysis of large sequence polymorphisms in Plasmodium falciparum blood-stage antigens

The in vivo sensitivity of Plasmodium falciparum to chloroquine and sulfadoxine/pyrimethamine was evaluated in children under 5 years of age in two areas of southern Nigeria in 1987. A modification...Full Text Available

1990-01-01

Hypoglycaemia and severe plasmodium falciparum malaria among pregnant sudanese women in an area characterized by unstable malaria transmission

Plasmodium falciparum, the causative agent of human malaria, invades host erythrocytes using several proteins on the surface of the invasive merozoite, which have been proposed...Full Text Available

2010-03-01

Diagnosis of Plasmodium falciparum infection using a solid-phase radioimmunoassay for the detection of malaria antigens

BackgroundPregnant women are more susceptible to severe Plasmodium falciparum malaria, which can lead to poor maternal and fetal outcomes. Few data exist on the...Full Text Available

Contrasting Population Structures of the Genes Encoding Ten Leading Vaccine-Candidate Antigens of the Human Malaria Parasite, Plasmodium falciparum

A serodiagnostic test has been developed for the detection of Plasmodium falciparum in infected blood. Using parasite antigens and infected red blood cells from in vitro...Full Text Available

1980-01-01

Common variation in the ABO glycosyltransferase is associated with susceptibility to severe Plasmodium falciparum malaria

The extensive diversity of Plasmodium falciparum antigens is a major obstacle to a broadly effective malaria vaccine but population genetics has rarely been used to guide vaccine design....Full Text Available

Blood Group A Antigen Is a Coreceptor in Plasmodium falciparum Rosetting

There is growing epidemiological and molecular evidence that ABO blood group affects host susceptibility to severe Plasmodium falciparum infection. The high frequency of common...Full Text Available

2008-02-15

The malaria parasite Plasmodium falciparum utilizes molecules present on the surface of uninfected red blood cells (RBC) for rosette formation, and a dependency on ABO antigens has...Full Text Available

2000-05-01

A prospective analysis of the Ab response to Plasmodium falciparum before and after a malaria season by protein microarray

Naturally acquired immunity to Plasmodium falciparum malaria in malaria holoendemic areas is characterized by the gradual, age-related development of protection against high-density...Full Text Available

Further assembly required: construction and dynamics of the endoplasmic reticulum network

Abs are central to malaria immunity, which is only acquired after years of exposure to Plasmodium falciparum (Pf). Despite the enormous worldwide burden of malaria,...Full Text Available

2010-04-13

Activity-Dependent Augmentation of Spontaneous Neurotransmission during Endoplasmic Reticulum Stress

The endoplasmic reticulum (ER) is a continuous membrane system comprising the nuclear envelope, ribosome-studded peripheral sheets and an interconnected network of smooth tubules extending throughout...Full Text Available

2010-07-01

Phylogenomic analyses of malaria parasites and evolution of their exported proteins

The endoplasmic reticulum (ER) is an essential cellular compartment responsible for Ca²⁺ sequestration, signaling, protein translation, folding as well as transport. Several acute...Full Text Available

2010-05-26

Efficacy of drug prophylaxis.

BackgroundPlasmodium falciparum is the most malignant agent of human malaria. It belongs to the taxon Laverania, which includes other ape-infecting Plasmodium...Full Text Available

1 2 3 4

Efficacy and safety of a fixed-dose oral combination of pyronaridine-artesunate compared with artemether-lumefantrine in children and adults with uncomplicated Plasmodium falciparum malaria: a randomised non-inferiority trial.

With the spread of chloroquine resistant Plasmodium falciparum the control of malaria has become increasingly complex. In recent years, particular concern has arisen over how best to prevent malaria...Full Text Available

1989-01-01

Antibodies from malaria-exposed pregnant women recognize trypsin resistant epitopes on the surface of Plasmodium falciparum-infected erythrocytes selected for adhesion to chondroitin sulphate A

PMID:20417857

2010-04-24

DEFF Research Database (Denmark)

Udgivelsesdato: 2004-Sep-6

2004-01-01

The structure of receptor-associated protein (RAP)

Refilling Intracellular Calcium Stores

The receptor-associated protein (RAP) is a molecular chaperone that binds tightly to certain newly synthesized LDL receptor family members in the endoplasmic reticulum (ER) and facilitates their delivery...Full Text Available

2007-08-01

Influence of KDEL on the Fate of Trimeric or Assembly-Defective Phaseolin

Within the cardiac cell, the movements of calcium ions are tightly regulated by a number of regulatory proteins including pumps, and channels. The sarcoplasmic reticulum (SR) is in large part...Full Text Available

2010-01-01

Ribose metabolism and nucleic acid synthesis in normal and glucose-6-phosphate dehydrogenase-deficient human erythrocytes infected with Plasmodium falciparum.

The tetrapeptide KDEL is commonly found at the C terminus of soluble proteins of the endoplasmic reticulum (ER), and it contributes to their localization by interacting with a receptor that recycles...Full Text Available

2001-05-01

Some features of chemoradiopathomorphosis of Ewing's sarcoma and reticulum cell sarcoma

The metabolism of pentose-phosphate was investigated in Plasmodium falciparum-infected normal and glucose-6-phosphate dehydrogenase (G6PD)-deficient human red blood cells in vitro. 5'-Phosphoribosyl-1-pyrophosphate...Full Text Available

1986-04-01

GNOM-LIKE1/ERMO1 and SEC24a/ERMO2 Are Required for Maintenance of Endoplasmic Reticulum Morphology in Arabidopsis thaliana[W

The paper is concerned with the results of a morphological study following chemoradiotherapy in 25 patients with Ewing's sarcoma and 14 patients with reticulum cell carcoma. The signs of therapeutic pathomophosis were observed in the first 3 days, and substitution of the connective tissue for a necrotized tumor started by the 3rd-4th week after the initiation of therapy. In some cases tumor growth and recurrences at the site of a treated tumor were observed.

Functional and Topological Analysis of Yeast Acyl-CoA:Diacylglycerol Acyltransferase 2, an Endoplasmic Reticulum Enzyme Essential for Triacylglycerol Biosynthesis*

The endoplasmic reticulum (ER) is composed of tubules, sheets, and three-way junctions, resulting in a highly conserved polygonal network in all eukaryotes. The molecular mechanisms responsible for...Full Text Available

2009-11-01

British Library Electronic Table of Contents (United Kingdom)

Acyl-CoA:diacylglycerol acyltransferase (EC 2.3.1.20) is a membrane protein present mainly in the endoplasmic reticulum. It catalyzes the final and committed step in the biosynthesis of triacylglycerol,...Full Text Available

2011-04-15

Summary Background There is a need for new artemisinin-based combination therapies that are convenient, effective, and safe. We compared the efficacy and safety of pyronaridine-artesunate with that of artemether-lumefantrine for treatment of uncomplicated P falciparum malaria. Methods This phase 3, parallel-group, double-blind, randomised, non-inferiority trial was undertaken in seven sites in Africa and three sites in southeast Asia. In a double-dummy design, patients aged 3-60 years with uncomplicated P falciparum malaria were randomly assigned in a 2:1 ratio to receive pyronaridine-artesunate once a day or artemether-lumefantrine twice a day, orally for 3 days, plus respective placebo. Randomisation was done by computer-generated randomisation sequence in blocks of nine by study centre....

2010-01-01

Statistical properties of nucleotide clusters in DNA sequences*

Multiplicity of Plasmodium falciparum infection in asymptomatic children in Senegal: relation to transmission, age and erythrocyte variants

Using the complete genome of Plasmodium falciparum 3D7 which has 14 chromosomes as an example, we have examined the distribution functions for the amount of C or G and A or T consecutively...Full Text Available

2005-05-01

Measuring the efficacy of anti-malarial drugs in vivo: quantitative PCR measurement of parasite clearance

BackgroundIndividuals living in malaria endemic areas generally harbour multiple parasite strains. Multiplicity of infection (MOI) can be an indicator of immune status. However,...Full Text Available

Impact of Plasmodium falciparum infection on the frequency of moderate to severe anaemia in children below 10 years of age in Gabon

BackgroundArtemisinin-based combination therapy, currently considered the therapy of choice for uncomplicated Plasmodium falciparum malaria in endemic countries,...Full Text Available

Evaluation of the OptiMAL Test for Rapid Diagnosis of Plasmodium vivax and Plasmodium falciparum Malaria

BackgroundImproving the understanding of childhood malarial anaemia may help in the design of appropriate management strategies.MethodsA...Full Text Available

Efficacy of sulphadoxine-pyrimethamine with or without artesunate for the treatment of uncomplicated Plasmodium falciparum malaria in southern Mozambique: a randomized controlled trial

The development of rapid and specific diagnostic tests to identify individuals infected with malaria is of paramount importance in efforts to control the severe public health impact of this disease....Full Text Available

1998-01-01

Diagnostic comparison of malaria infection in peripheral blood, placental blood and placental biopsies in Cameroonian parturient women

BackgroundAn artemisinin-based combination therapy, artesunate (AS) plus sulphadoxine-pyrimethamine (SP), was compared to SP monotherapy to provide evidence of further treatment...Full Text Available

Deletion of the Plasmodium falciparum Merozoite Surface Protein 7 Gene Impairs Parasite Invasion of Erythrocytes?

BackgroundIn sub-Saharan Africa, Plasmodium falciparum malaria in pregnancy presents an enormous diagnostic challenge. The epidemiological and clinical relevance...Full Text Available

Comparative Transcriptional and Genomic Analysis of Plasmodium falciparum Field Isolates

Merozoite surface proteins have been implicated in the initial attachment to the host red blood cell membrane that begins the process of invasion, an important step in the life cycle of the malaria...Full Text Available

2008-12-01

An improved method for undertaking limiting dilution assays for in vitro cloning of Plasmodium falciparum parasites

Mechanisms for differential regulation of gene expression may underlie much of the phenotypic variation and adaptability of malaria parasites. Here we describe transcriptional variation among culture-adapted...Full Text Available

2009-10-01

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Accumulation of Plasmodium berghei-Infected Red Blood Cells in the Brain Is Crucial for the Development of Cerebral Malaria in Mice?

BackgroundObtaining single parasite clones is required for many techniques in malaria research. Cloning by limiting dilution using microscopy-based assessment for parasite growth...Full Text Available

ABO blood group phenotypes influence parity specific immunity to Plasmodium falciparum malaria in Malawian women

Cerebral malaria is the most severe complication of human infection with Plasmodium falciparum. It was shown that Plasmodium berghei ANKA-induced cerebral malaria was...Full Text Available

2010-09-01

The Cytokinin Receptors of Arabidopsis Are Located Mainly to the Endoplasmic Reticulum¹^[W]^[OA]

BackgroundBlood group O has been significantly associated with increased placental malaria infection in primiparae and reduced risk of infection in multiparae in the Gambia, an area...Full Text Available

Sec24C is required for docking the prechylomicron transport vesicle with the Golgi

The plant hormone cytokinin is perceived by membrane-located sensor histidine kinases. Arabidopsis (Arabidopsis thaliana) possesses three cytokinin receptors: ARABIDOPSIS HISTIDINE...Full Text Available

2011-08-01

SARCOLEMMAL INVAGINATIONS CONSTITUTING THE T SYSTEM IN FISH MUSCLE FIBERS

The rate-limiting step in the transit of dietary fat across the intestinal absorptive cell is its exit from the endoplasmic reticulum (ER) in a specialized ER-to-Golgi transport vesicle, the prechylomicron...Full Text Available

2010-05-01

Regulation of basal cellular physiology by the homeostatic unfolded protein response

Striated muscle fibers from the body and tail myotomes of a fish, the black Mollie, have been examined with particular attention to the sarcoplasmic reticulum (SR) and transverse tubular (or T) system....Full Text Available

1964-09-01

Poikiloderma atrophicans vasculare as a pointer to reticulosis of the skin

The extensive membrane network of the endoplasmic reticulum (ER) is physically juxtaposed to and functionally entwined with essentially all other cellular compartments. Therefore, the ER must sense...Full Text Available

2010-05-31

Modulation of B-cell endoplasmic reticulum calcium homeostasis by Epstein-Barr virus Latent Membrane Protein-1

A case of reticulosis of the skin (mycosis fungoides) terminating in reticulum cell sarcoma is described where the features of poikiloderma atrophicans vasculare had been present for 40 years. The...Full Text Available

1975-07-01

Homology of SMP domains to the TULIP superfamily of lipid-binding proteins provides a structural basis for lipid exchange between ER and mitochondria

BackgroundCalcium signaling plays an important role in B lymphocyte survival and activation, and is critically dependent on the inositol-1,4,5-tris-phosphate-induced...Full Text Available

Role of death receptor, mitochondrial and endoplasmic reticulum pathways in different stages of degenerative human lumbar disc

Mitochondria must uptake some phospholipids from the endoplasmic reticulum (ER) for the biogenesis of their membranes. They convert one of these lipids, phosphatidylserine, to phosphatidylethanolamine,...Full Text Available

2010-08-15

British Library Electronic Table of Contents (United Kingdom)

Intervertebral disc (IVD) cell apoptosis has been suggested to play an important role in promoting the degeneration process. It has been demonstrated that IVD cell apoptosis occurs through either death receptor, mitochondrial or endoplasmic reticulum (ER) pathway. Our study aimed to explore the relationship among these three pathways and grade of IVD degeneration (IVDD). IVDs were collected from patients with lumbar fracture, vertebral tumor, disc herniation or spondylolisthesis. IVDs were distinguished by MRI and histomorphological examination, cell apoptosis was detected by TUNEL staining. Biomarkers of these three apoptosis pathways were detected by RT-PCR and Western blot. Furthermore, the correlation between apoptosis pathways biomarkers and disc pathology were analyzed. Nucleus pulpo...

2011-01-01

Inhibitory effect of ?/?-carrageenan from red alga Tichocarpus crinitus on the development of a potato virus X infection in leaves of Datura stramonium L.

British Library Electronic Table of Contents (United Kingdom)

The effect of ?/?-carrageenan from red alda Tichocarpus crinitus on the development of a potato virus X (PVX) infection in the leaves of Datura stramonium L. has been studied. The treatment of leaves with carrageenan stimulates a protein synthesis in the cells, causing an increase in the size of nucleoli and in the number of mitochondria and membranes of the rough endoplasmic reticulum. At the same time, such treatment slightly stimulates lytic processes, causing an increase in the number of smooth endoplasmic reticulum cisternae, dictyosomes, and cytoplasmic vacuoles and the formation of cytoplasmic electron-transparent zones. The carrageenan-induced stimulation of lytic processes results in the destruction of viral particles and can be considered as one of the defense mechanisms, prevent...

2010-01-01

Codon-modifications and an endoplasmic reticulum-targeting sequence additively enhance expression of an Aspergillus phytase gene in transgenic canola

British Library Electronic Table of Contents (United Kingdom)

Transgenic plants offer advantages for biomolecule production because plants can be grown on a large scale and the recombinant macromolecules can be easily harvested and extracted. We introduced an Aspergillus phytase gene into canola (Brassica napus) (line 9412 with low erucic acid and low glucosinolates) by Agrobacterium-mediated transformation. Phytase expression in transgenic plant was enhanced with a synthetic phytase gene according to the Brassica codon usage and an endoplasmic reticulum (ER) retention signal KDEL that confers an ER accumulation of the recombinant phytase. Secretion of the phytase to the extracellular fluid was also established by the use of the tobacco PR-S signal peptide. Phytase accumulation in mature seed accounted for 2.6% of the total soluble proteins. The enzy...

2006-01-01

T Cell Responses to the RTS,S/AS01_E and RTS,S/AS02_D Malaria Candidate Vaccines Administered According to Different Schedules to Ghanaian Children

Evaluation of the rapid diagnostic test SDFK40 (Pf-pLDH/pan-pLDH) for the diagnosis of malaria in a non-endemic setting

BackgroundThe Plasmodium falciparum pre-erythrocytic stage candidate vaccine RTS,S is being developed for protection of young children against...Full Text Available

An open randomized clinical trial in comparing two artesunate-based combination treatments on Plasmodium falciparum malaria in Nigerian children: artesunate/sulphamethoxypyrazine/pyrimethamine (fixed dose over 24 hours) versus artesunate/amodiaquine (fixed dose over 48 hours)

BackgroundThe present study evaluated the SD Bioline Malaria Ag 05FK40 (SDFK40), a three-band RDT detecting Plasmodium falciparum-specific parasite lactate dehydrogenase...Full Text Available

The Function of Hypoxia-Inducible Factor (HIF) Is Independent of the Endoplasmic Reticulum Protein OS-9

BackgroundSeveral studies have demonstrated the efficacy of artemisinin-combination therapy (ACT) across malaria zones of the world. Fixed dose ACT with shorter courses and fewer...Full Text Available

Changes in the profile structure of the sarcoplasmic reticulum membrane induced by phosphorylation of the Ca2+ ATPase enzyme in the presence of terbium: a time-resolved x-ray diffraction study.

The protein “amplified in osteosarcoma-9” (OS-9) has been shown previously to interact with the prolyl hydroxylases PHD2 and PHD3. These enzymes initiate oxygen-dependent degradation...Full Text Available

Advancing Age Alters the Contribution of Calcium Release From Smooth Endoplasmic Reticulum Stores in Superior Cervical Ganglion Cells

The design of the time-resolved x-ray diffraction experiments reported in this and an accompanying paper was based on direct measurements of enzyme phosphorylation using [gamma-32P]ATP that were employed...Full Text Available

1994-05-01

Temporal development of GABA agonist induced alterations in ultrastructure and GABA receptor expression in cultured cerebellar granule cells

In superior cervical ganglion (SCG) neurons calcium-induced calcium release (CICR), mediated by ryanodine receptors (RyRs), contributes to stimulation-evoked intracellular calcium ([Ca²⁺]_i)...Full Text Available

2009-01-01

DEFF Research Database (Denmark)

The temporal development of the effect of THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol) on the ultrastructure composition and GABA receptor expression in cerebellar granule cells was investigated by quantitative electron microscopy (morphometric analysis) and GABA binding assays. It was found that the cytoplasmic density of smooth endoplasmic reticulum was decreased, while the cytoplasmic density of rough endoplasmic reticulum, Golgi apparatus, vesicles and coated vesicles was greatly enhanced after exposure of the cells to THIP (150 microM) for only 1 hr. In cerebellar granule cells exposed to THIP (150 microM) for 3 hr low affinity GABA receptors were induced. These findings show that the effect of THIP on the ultrastructure composition and GABA receptor expression in cultured cerebellar granule cells may be interrelated and moreover it is likely that the turn-over of GABA receptors is extremely fast.

1987-01-01

1 2 3 4

Cells producing insulin-like androgenic gland hormone of the giant freshwater prawn, Macrobrachium rosenbergii, proliferate following bilateral eyestalk-ablation

British Library Electronic Table of Contents (United Kingdom)

We found that the androgenic gland (AG) of Macrobrachium rosenbergii possesses three cell types. Type I cells are small polygonal shaped-cells (13.4 mu m in diameter), stain strongly with hematoxylin-eosin (H&E), have abundant multilayered rough endoplasmic reticulum (rER), and nuclei containing mostly heterochromatin. Type II cells are slightly larger (18.6 mu m in diameter), stain lightly with H&E, have rER with dilated cisternae, and nuclei containing mostly euchromatin. Type III cells (previously undescribed) are similar in size and shape to type I cells, but the cytoplasm is unstained and they have a high amount of smooth endoplasmic reticulum (sER) and mitochondria with tubular cristae. Bilateral eyestalk-ablation resulted in AG hypertrophy with a proliferation and predominance of ty...

2011-01-01

Bip overexpression, but not CHOP inhibition, attenuates fatty-acid-induced endoplasmic reticulum stress and apoptosis in HepG2 liver cells

British Library Electronic Table of Contents (United Kingdom)

Aims: In this study we investigated whether attenuation of endoplasmic reticulum stress (ER stress) could protect HepG2 cells from free fatty acid (FFA)-induced apoptosis. Main methods: Human liver cell line HepG2 cells were exposed to Sodium Palmitate (Pa) or Sodium Oleate (Ol). Apoptosis and ER stress of HepG2 cells were analyzed with flow cytometry, real-time RT-PCR and Western Blotting. An expression plasmid encoding for the ER chaperone immunoglobulin heavy chain-binding protein (Bip) was transfected into HepG2 cells to attenuate ER stress. Small interfering RNA siCHOP was used to knockdown the expression of C/EBP Homologous Protein (CHOP) in HepG2. Key findings: Pa led to cytotoxicity and apoptosis in HepG2 cells in a dose-dependent pattern and also induced ER stress indicated by inc...

2010-01-01

Carbon tetrachloride-induced release of calcium from isolated hepatocytes

Antiprotozoal and cytotoxic activities in vitro of Colombian Annonaceae

Studies have shown that CCl_4 administration to rats inhibits endoplasmic reticulum calcium pump activity and reduces the amount of calcium associated with subsequently isolated microsomal subcellular fractions. This report confirms that exposure of isolated hepatocytes to CCl_4 rapidly produces these effects in isolated parenchymal cells and demonstrates that when isolated hepacytes are exposed to CCl_4 calcium is rapidly released from cells. This release can be detected with a calcium ion-selective electrode when cells are incubated in a medium with low extracellular calcium. Calcium released from an intracellular pool(s) may initiate hepatotoxic changes in liver. (author).

British Library Electronic Table of Contents (United Kingdom)

Ethnobotanical and chemotaxonomical studies for antiparasitic activity of Colombian Annonaceae were carried out. In vitro antiprotozoal activity of 36 extracts obtained from six different species was determined against promastigotes of three Leishmania species, epimastigotes of Trypanosoma cruzi and both chloroquine sensitive (F32) and resistant (W2) Plasmodium falciparum. Cytotoxic activity was evaluated in U-937 cells. Active extracts were selected according their selectivity index (SI). Extracts from Annona muricata, Rollinia exsucca, Rollinia pittieri and Xylopia aromatica were active against Leishmania spp. and Trypanosoma cruzi showing IC50 values lower than 25mg/ml. Hexane extract from Rollinia pittieri leaves was the most selective against Trypanosoma cruzi and Leishmania spp. (IS=...

2007-01-01

Anti-plasmodial activity and toxicity of extracts of plants used in traditional malaria therapy in Meru and Kilifi Districts of Kenya

British Library Electronic Table of Contents (United Kingdom)

The methanol and aqueous extracts of 10 plant species (Acacia nilotica, Azadirachta indica, Carissa edulis, Fagaropsis angolensis, Harrissonia abyssinica, Myrica salicifolia, Neoboutonia macrocalyx, Strychnos heningsii, Withania somnifera and Zanthoxylum usambarensis) used to treat malaria in Meru and Kilifi Districts, Kenya, were tested for brine shrimp lethality and in vitro anti-plasmodial activity against chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum (NF54 and ENT30). Of the plants tested, 40% of the methanol extracts were toxic to the brine shrimp (LD5050N. macrocalyx had the highest toxicity to brine shrimp nauplii (LD50 21.04+-1.8mg/ml). Methanol extracts of the rest of the plants exhibited mild or no brine shrimp toxicity (LD50>50mg/ml). The aqueo...

2006-01-01

Delayed Afterdepolarization in Intact Canine Sinoatrial Node as a Novel Mechanism for Atrial Arrhythmia

British Library Electronic Table of Contents (United Kingdom)

Delayed Afterdepolarization in Sinoatrial Node. Introduction: Recent evidence indicates that spontaneous sarcoplasmic reticulum Ca release and Na-Ca exchanger current activation contribute to the sinoatrial node (SAN) automaticity. These findings suggest that SAN activity may share mechanisms that underlie both automaticity and triggered activity. The aim of this study is to test the hypothesis that spontaneous, nonvoltage gated, intracellular Ca (Cai) elevation may induce delayed afterdepolarization (DAD) in intact SAN during isoproterenol infusion. Methods and Results: We simultaneously mapped Cai and membrane potential in 31 isolated Langendorff-perfused canine right atriums (RA). Isoproterenol increased heart rate and late diastolic Cai elevation (LDCAE) of the superior SAN, leading to...

2011-01-01

Induction of biotransformation in the liver of Eel (Anguilla anguilla L. ) by sublethal exposure to dinitro-o-cresol: An ultrastructural and biochemical study

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Structural and functional alterations in hepatocytes of the European eel, Anguilla anguilla, following a 4-week-exposure to 5, 50, and 250 micrograms/liter dinitro-o-cresol (DNOC) were investigated by means of electron microscopy and biochemistry and compared to liver pathology in eels exposed to the chemical spill into the Rhine river at Basle in November 1986. Whereas phenological parameters (growth, condition factor) are unaffected, ultrastructural and biochemical alterations are detectable at greater than or equal to 50 and 5 micrograms/liter DNOC, respectively. Structural modifications include: rounding-up of the nuclei; fractionation and reduction of the rough endoplasmic reticulum; proliferation of the smooth endoplasmic reticulum (SER), mitochondria, peroxisomes, and lysosomes; bundles of rod-shaped SER profiles; annulate lamellae; membrane whorls within mitochondria; crystallization of the peroxisomal matrix and glycogen bodies; ...

1991-04-01

The frontal weapon of the termite Armitermes euamignathus Silvestri (Isoptera, Termitidae, Nasutitermitinae)

Scientific Electronic Library Online (English)

Abstract in english Frontal weapon is the term used to designate the apparatus consisting of frontal gland and associated structures that participate in the chemical defense of termite soldiers. The ultra structure of the frontal gland and the scanning microscopy of the soldier head was investigated in the termite Amiitermes euamignathus Silvestri, 1901.Campaniform sensilla was not observed but there were 80 to100 sensory bristles around the frontal pore. The glandular epithelium shows only (more) class 1 cells according 10 the classification of NOIROT & QUENNEDEY (1974, 1991). The glandular cells are characterized by apical microvilli, a basal labyrinth and a large quantity of smooth endoplasmic reticulum which forms dense zones throughout the cytoplasm. The secretion is concentrated mainly in the basal pole of the cell and consists of large lipid droplets. The secretory epithelium is covered by a thick apical cuticle composed of a thin outer epicuticle, a ...

2001-06-01

Subcellular distribution of ryanodine receptors in the cardiac muscle of carp (Cyprinus carpio).

Ion movements in cell death: from protection to execution

We examined the subcellular localization of ryanodine receptors (RyR) in the cardiac muscle of carp using biochemical, immunohistochemical, and electron microscopic methods and compared it with those of rats and guinea pigs. To achieve this goal, an anti-RyR antibody was newly raised against a synthetic peptide corresponding to an amino acid sequence that was conserved among all sequenced RyRs. Western blot analysis using this antibody detected a single RyR band following the SDS-PAGE of sarcoplasmic reticulum (SR) membranes from carp atrium and ventricle as well as from mammalian hearts and skeletal muscles. The carp heart band had slightly greater mobility than those of mammalian hearts. Although immunohistochemical staining showed evident striations corresponding to the Z lines in longitudinal sections of mammalian hearts, clusters of punctate staining, in contrast, were distributed ubiquitously throughout carp atrium and ventricle. Electron microscopic images ...

2003-06-12

Scientific Electronic Library Online (English)

Abstract in english Cell death is preceded by severe disruption of inorganic ion homeostasis. Seconds to minutes after an injury, calcium, protons, sodium, potassium and chloride are exchanged between the cell and its environment. Simultaneously, ions are shifted between membrane compartments inside the cell, whereby mitochondria and endoplasmic reticulum play a crucial role. Depending of the type and severity of injury, two mutually exclusive metastable states can be reached, which predict (more) the final outcome. Cells characterized by large increases in cytosolic [Ca2+], [Na+]; and [Mg2+] swell and die by necrosis; alternatively, cells characterized by high [H+]and low [K+], with normal [Na+] and normal to moderate [Ca2+] increases die by apoptosis. The levels of these ions represent central determinants in signaling events leading to cell death. Their movements are explained mechanistically by specific modulation of membrane transport proteins including ...

2002-01-01

An evaluation of the pendulum technique of electron beam therapy

A CD33-specific single-chain immunotoxin mediates potent apoptosis of cultured human myeloid leukaemia cells.

Electron beam therapy of lesions such as cutaneous metastatic carcinoma and reticulum cell sarcoma is performed via multiple portals for a wide irradiation field. However, the dose distribution in border areas is generally uneven, resulting in hot and cold dose areas depending on the intervals of the portals. We performed electron irradiation by the pendulum technique, especially on curved areas, and evaluated the technique in various respects. Pendulum electron beam irradiation is indicated when the length of the cone must be reduced in order to deliver the target volume near the skin surface as well as to avoid the occurrence of hot spots deep in the body. We prepared a 15cm rotating cone by cutting a 30cm fixed irradiation cone. The modification posed no disadvantages in terms of extent and flatness of the beam, or stability during rotation. After determining the relationship between the rotation speed and the dose, the technique was successfully applied to a ...

A novel single-chain immunotoxin was constructed by combining a CD33-specific single chain Fv (scFv) antibody fragment with an engineered variant of Pseudomonas exotoxin A (ETA). The variant toxin carries the KDEL peptide at its C-terminus, a cellular peptide mediating improved retrograde transport to the endoplasmic reticulum. The purified recombinant fusion protein induced potent apoptosis of the human myeloid cell lines U937, HL-60 and THP-1. Up to 98% of U937 cells were eliminated after treatment for 72 h with a single dose of 500 ng/ml (c. 7 nmol/l). Killing was antigen-specific and occurred by apoptosis. A control protein, consisting of a CD19-specific scFv antibody fragment fused to the ETA-KDEL toxin, failed to induce death of the CD19-negative cell lines U937, HL-60 and THP-1. The CD33-ETA toxin also mediated apoptosis of fresh patient-derived acute myeloid leukaemia cells from bone marrow and peripheral blood. The pronounced antigen-restricted ...

2006-04-01

Synthesis, characterization and biologic effects of polybrominated naphthalenes

The IRG protein Irgm3 preserves cell survival during coxsackievirus B3 (CVB3) infection. However, the molecular mechanisms are not clear. Here, we examined the effect of Irgm3 expression on ER stress triggered by pharmacological agents or CVB3 infection. In Tet-On/Irgm3 HeLa cells, Irgm3 expression suppressed either chemical- or CVB3-induced upregulation of glucose-regulated protein78. Further, Irgm3 strongly inhibited the activation of both the PERK and ATF6 pathways of ER stress responses, which further led to the diminished phosphorylation of eIF2?, reduced cleavage/activation of transcription factor SREBP1 and attenuated induction of proapoptotic genes CHOP and GADD34. These data were further supported by experiments using Irgm3 knockout mouse embryonic fibroblasts, in which the ER stress induced by CVB3 was not relieved due to the lack of Irgm3 expression. In addition, the tunicamycin-triggered ER stress promoted the subsequent CVB3 infection. The effect of Irgm3 on ER stress and ...

2011-10-10

Energy Technology Data Exchange (ETDEWEB)

Although polybrominated naphthalenes (PBNs) are contaminants of the commercial fire retardant fireMaster BP-6, the individual PBN isomers have not been identified. In order to study PBNs possessing an analogous level of bromination to those found in fireMaster BP-6, three synthetic PBN mixtures, averaging 5.0, 5.3, and 5.6 bromines per naphthalene were synthetized and partially characterized. The PBN mixtures were administered to immature male Wistar rats and found to be potent inducers of cytochrome P-450-dependent monooxygenases. At the lowest dose tested, 30 mumol X kg-1, each PBN mixture caused maximal induction of benzo(a)pyrene hydroxylase activity. On the basis of enzyme activities, ligand-binding spectra and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the PBN mixtures were determined to be 3-methylcholanthrene-type inducers of cytochrome P-450 (P-448), resembling qualitatively the most toxic polyhalogenated biphenyls, dibenzofurans, and dioxins in this respect. ...

1984-07-01

Organ culture of mammalian skin and the effects of ultraviolet light and testosterone on melanocyte morphology and function

Antimalarial activity of selected Sudanese medicinal plants with emphasis to Maytenus senegalensis

Scrotal skin of black Long-Evans rats and human thigh skin were maintained in vitro as organ cultures for as long as 14 days, and examined histologically using the combined skin splitting and Dopa techniques. Selected rat skin cultures received testosterone in the culture medium and/or were irradiated with ultraviolet light (290 to 320 nm uvl). With increased time in culture, scrotal melanocytes round up and there is an increase in epidermal pigmentation. Human skin behaves similarly; after eight days in vitro human melanocytes also become rounded, but remain strongly Dopa-positive. Addition of exogenous testosterone to cultured rat skin maintains dendritic morphology of melanocytes, but cell body size is still reduced. uvl irradiation stimulates melanocytes in rat skin cultures, maintaining their dendritic morphology and increasing epidermal and dermal pigmentation. Cultured skin receiving both uvl and testosterone illustrates a synergistic effect. Electron microscopic examination of ...

1978-05-01

Neurotoxicity of low-dose repeatedly intranasal instillation of nano- and submicron-sized ferric oxide particles in mice

The aim of the present study is to identify and characterize the antimalrial agents from traitional Sudanese medicinal plants. 49 plants parts representing 26 species from 15 families were extracted and screened for their in vitro antimalrial activity using P. falciparum strain 3D7 which is chloroquine sensitive and Dd2 strain which is chloroquine resistant and pyrimethamine sensitive.The plant species investigated exhibited diverse botanical families. They includes Annonaceae, Aristolochiaceae, Asteraceae, Balantiaceae, Caesalpiniceae, Celasteraceae, Cucurbitaceae, Fabaceae, Graminae, Meliaceae, Myrtaceae, Polygonaceae, Rubiaceae, Rutaceae, and simaroubaceae. The evaluation of these plants for their antimalarial activity and their effect on lymphocyte proliferation was carried out. 57 extracts were tested on the chloroquine sensitive strain (3D7). Where 34 extracts (59%) exhibited significant activity against 3D7 with IC_5_0 values #100 #mu# g/ml), where as ...