Search results for "Lethal"
showing 10 items of 134 documents
Mutagenit�tspr�fung bestrahlter Lebensmittel mit dem ?dominant lethal test?
1973
An insgesamt 716 Ratten und 750 Mausen wurde eine mogliche mutagene Wirkung einer bestrahlten Nahrung gepruft. Fertilitat, Tragezeitdauer, Wurfgrose, Aufzuchtleistung und Geschlechtsverhaltnis zeigten in 5 aufeinanderfolgenden Rattengenerationen keine Storungen in der Reproduktionsfahigkeit an. Es konnte kein Anstieg der Misbildungsrate bei den Rattenfeten beobachtet werden. Auch die Fruchtbarkeit der mannlichen und der weiblichen Tiere der Mausegeneration war ungestort. Durch den “dominant lethal test” an Ratten und Mausen konnte keine embryotoxische oder mutagene Wirkung der bestrahlten Nahrung festgestellt werden, die sich in mit den verwendeten statistischen Methoden erfasbaren Untersch…
Linfoma angiocéntrico localizado en paladar
2001
Resumen Los linfomas angiocentricos son neoplasias muy poco frecuentes en nuestra area geografica. Suelen presentarse en la region oronasal como lesiones de tipo necrotico, en concreto en la zona mediofacial, con una evolucion rapida y un pronostico sombrio. Inmunohistoquimicamente se ha detectado que en estas neoplasias las celulas malignas corresponden a linfocitos T. Ademas estudios recientes apoyan la hipotesis del posible papel del virus de Epstein-Barr como posible factor etiologico. Presentamos en este articulo el caso clinico de un hombre de 67 anos con una lesion ulcerada en el paladar, de corto tiempo de evolucion y que tras estudio histopatologico e inmunohistoquimico se confirmo…
In vivo effects of intravascularly applied Escherichia coli hemolysin: dissociation between induction of granulocytopenia and lethality in monkeys.
1993
The effects of intravascular application of endotoxin-depleted Escherichia coli hemolysin (HlyA) was studied in rabbits and monkeys. In rabbits, bolus application of HlyA calculated to effect final blood levels of approximately 2-3 HU/ml (200-300 ng/ml) caused an acute fall of polymorphonuclear blood leukocytes to less than 20% of starting levels within 5 min. Additionally, platelet counts dropped to approximately 30% of starting levels, whereas lymphocyte counts varied considerably and seldom fell to less than 50%. Nine out ten animals that received 2-4 HU/ml toxin died within 90 min post application. These animals presented with signs of acute respiratory failure and post mortem inspectio…
The Cell Cycle-Specific Growth-Inhibitory Factor Produced by Actinobacillus actinomycetemcomitans Is a Cytolethal Distending Toxin
1998
ABSTRACT Actinobacillus actinomycetemcomitans has been shown to produce a soluble cytotoxic factor(s) distinct from leukotoxin. We have identified in A. actinomycetemcomitans Y4 a cluster of genes encoding a cytolethal distending toxin (CDT). This new member of the CDT family is similar to the CDT produced by Haemophilus ducreyi . The CDT from A. actinomycetemcomitans was produced in Escherichia coli and was able to induce cell distension, growth arrest in G 2 /M phase, nucleus swelling, and chromatin fragmentation in HeLa cells. The three proteins, CDTA, -B and -C, encoded by the cdt locus were all required for toxin activity. Antiserum raised against recombinant CDTC completely inhibited …
Correlation of Pharmacological Properties of a Group of Hypolipaemic Drugs by Molecular Topology
1996
Abstract This investigation was undertaken to test the ability of the molecular connectivity model to predict the percentage of plasma protein binding, the percentage of total cholesterol reduction and oral LD50 in rats of a group of hypolipaemic drugs using multi-variable regression equations with multiple correlation coefficients, standard error of estimate, degrees of freedom, F-Snedecor function values, Mallow's CP and Student's t-test as criteria of fit. Regression analyses showed that the molecular connectivity model predicts these properties. Corresponding stability (cross validation) studies were made on the selected prediction models which confirmed their goodness of fit. The resul…
Gut microbiota imbalance and colorectal cancer
2016
International audience; The gut microbiota acts as a real organ. The symbiotic interactions between resident micro-organisms and the digestive tract highly contribute to maintain the gut homeostasis. However, alterations to the microbiome caused by environmental changes (e.g., infection, diet and/or lifestyle) can disturb this symbiotic relationship and promote disease, such as inflammatory bowel diseases and cancer. Colorectal cancer is a complex association of tumoral cells, non-neoplastic cells and a large amount of micro-organisms, and the involvement of the microbiota in colorectal carcinogenesis is becoming increasingly clear. Indeed, many changes in the bacterial composition of the g…
Biological responses of Rhynchophorus ferrugineus (Coleoptera: Curculionidae) to Steinernema carpocapsae (Nematoda: Steinernematidae).
2013
Rhynchophorus ferrugineus (Olivier 1790) (Coleoptera: Curculionidae) is becoming a serious problem in Mediterranean areas where it is well-adapted, and now is present even in the United States (California). The infestations are primarily in urban areas where chemical control is not advisable and million of Euros are spent to control it. The effects of the entomopathogenic nematode Steinernema carpocapsae (Nematoda: Steinernematidae) on mortality, growth, as well as the immune activity of R. ferrugineus larvae, were investigated. R. ferrugineus mortality exhibited a positive trend with the dosage and duration of exposure to S. carpocapsae. The median lethal dose and median lethal time, impor…
Using the critical body residue approach to determine the acute toxicity of cadmium at varying levels of water hardness and dissolved organic carbon …
2011
Abstract The linkage between acute adverse effects of cadmium and internal cadmium levels were investigated for the oligochaete worm Lumbriculus variegatus in water at varying degrees of hardness and two different dissolved organic carbon (DOC) concentrations. The LC50s for the effect of cadmium on the survival of the worms greatly differed depending on water hardness and DOC. We found less variability in internal metal toxicity metrics (lethal residue; LR50s) than in external toxicity metrics (lethal concentration; LC50s): LC50s varied from 2.4 to 66.1 μmol/L, while LR50s varied only from 226 to 413 μmol/kg wet weight. The cadmium body burden appeared to be independent of exposure conditio…
Relationship between esterase activity and acrinathrin and methiocarb resistance in field populations of western flower thrips, Frankliniella occiden…
2006
The western flower thrips, Frankliniella occidentalis (Pergande), is a serious pest in the south-east of Spain owing to its direct feeding on crops, transmission of the tomato spotted wilt virus and its very high level of resistance to insecticides. Mechanisms of resistance were examined using field populations of F. occidentalis with different susceptibilities to acrinathrin, methiocarb (selective insecticides), endosulfan, metamidophos and deltamethrin (broad-spectrum insecticides). Esterase activity towards alpha-naphthyl acetate and p-nitrophenyl acetate in resistant strains was significantly higher than in the reference strain (MLFOM) for both model substrates. This higher activity was…