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11.
The mycotoxin cyclopiazonic acid (CPA) is a potential contaminant of processed foods, grain and poultry. Twelve male Sprague-Dawley rats were given oral doses of 0, 0.2, 0.6, 2.0 or 4.0 mg CPA/kg body weight/day for 13 consecutive weeks to study its potential subchronic toxicity. No dose-related mortality or morbidity occurred. General appearance, behavior, body weight gain and food consumption of all groups were similar. CPA had no definite adverse hematologic or serum chemistry effects, although serum creatinine concentrations of rats given 2.0 and 4.0 mg CPA/kg BW were increased after seven and 13 weeks. Mild to focally moderate acute inflammation of the lamina propria and submucosa of the gastric epithelium was found in animals given 0.6 mg CPA/kg BW. No other dose-related microscopic lesions were found. Ultrastructural examination of the livers revealed subtle disruption of the cisternal pattern of the endoplasmic reticulum with ribosomal detachment in animals receiving 4.0, but not 2.0, mg CPA/kg BW. These data suggest that the toxic effects in rats of repeated, daily oral exposure to CPA may be less than previously reported. The possible relationship between toxicity and CPA epimerization is considered. 相似文献
12.
Hans Jørgen Nielsen Henrik Nielsen Flemming Moesgaard Niels Tvede Kim Klarlund Bendt Mansa Aage Drivsholm 《Cancer immunology, immunotherapy : CII》1990,32(3):201-205
Summary Multiple myeloma is characterized by an increased susceptibility to infections and to other malignancies. In a double-blind, placebo-controlled study the potential impact of immunomodulation by ranitidine was studied in 20 patients with multiple myeloma. Three patients were untreated, while 17 after previous cytotoxic therapy were in a stable phase of their disease. All were without clinical signs of infections and at that time had not been treated with other immunomodulating agents. The patients were randomized to oral ranitidine 300 mg twice a day for 21 days or placebo, and several immunological parameters related to multiple myeloma were studied. The blood monocyte chemotactic response was improved in patients treated with ranitidine, and superoxide anion production increased from 2.02 nmol/min to 3.86 nmol/min (median values), while it was unchanged in patients given placebo (2.19–2.25 nmol/min) (P <0.005 between groups). Among ranitidine-treated patients spontaneous NK cell activity was unchanged, while in vitro interleukin-2- and interferon--stimulated NK cell activity decreased (P <0.03, respectively). As production of oxygen radicals constitutes an important mechanism of monocyte killing activity against microorganisms and probably against malignant cells, it is suggested that ranitidine may be of beneficial impact in the treatment of multiple myeloma. 相似文献
13.
Tina Pallesen Annette Vangsted Lars Drivsholm Henrik Clausen Jesper Zeuthen Håkan Wallin 《Glycoconjugate journal》1992,9(6):331-335
We here report an enzyme linked immunosorbent assay (ELISA) and a scintillation proximity assay (SPA) for detection of the ganglioside FucGM1 in sera from small cell lung cancer (SCLC) patients. The SPA was more sensitive and reproducible than the ELISA. In this assay, monoclonal antibodies specific for FucGM1 were bound to SPA particles and incubated with labelled FucGM1 and 100 µl test-serum overnight, and counted in a -counter. The sensitivity was 0.2 ng. Seven out of twenty sera from SCLC patients were positive, whereas none of twenty sera from healthy individuals were positive for FucGM1. The SPA was more sensitive than the previously reported HPTLC as well as a direct ELISA.Abbreviations MAb
monoclonal antibody
- SPA
scintillation proximity assay
- HPTLC
high performance thin layer chromatography
- SCLC
small cell lung cancer
- FucGM1
Fuc1-2Gal1-3GalNAc1-4(NeuAc2-3)-Gal1-4Glc1-1Cer
- ELISA
enzyme linked immunosorbent assay
- FCS
foetal calf serum
- PBS
phosphate buffered saline 相似文献
14.
The effects of the local anesthetic dibucaine on coupling between electron transport and ATP synthesis-hydrolysis by the coupling-factor complex (CF0CF1 ATPase) were investigated in thylakoid membranes from Spinacia oleracea L. cv. Monatol. Evidence is presented that inhibition of ATP synthesis was produced by a specific uncoupling mechanism which was based on dibucaine-membrane surface interactions rather than on the interaction of dibucaine with the ATPase complex. Dibucaine reduced the osmotic space of thylakoid vesicles. At low pH of the medium it stimulated ATP hydrolysis beyond the rates obtained with optimum concentrations of ‘classical’ uncouplers. After addition of dibucaine, there was displacement of membrane-bound Mg2+ and strong thylakoid stacking in the presence of only low Mg2+ concentrations. Inhibition of ATP synthesis and transmembrane pH gradient increased with medium pH. Hydrolysis of ATP by isolated CF1 and the CF0CF1 complex was only slightly affected by dibucaine. The data are discussed assuming the involvement of localized proton channels on the membrane surface in protonic coupling of electron transport and ATP synthesis. A hypothesis for the mechanisms of action of local anesthetics at the thylakoid membrane is presented. 相似文献
15.
Ingemar Fries Aasne Aarhus Henrik Hansen Seppo Korpela 《Experimental & applied acarology》1991,10(3-4):279-287
Thirty-five honey-bee colonies, originally free fromVarroa jacobsoni (Oudemans) were monitored approximately every third week for the presence of the mite during 16 months following an initial introduction of five to eight adultVarroa females in early July. Investigations of hive debris detected the presence ofV. jacobsoni in 22 colonies (63%) within three months of the mite introduction. During the first winter period (October–April), mites were found in the hive debris of 13 colonies (37%). In terms of detectingVarroa during the summer in colonies with sealed brood, investigations of hive debris were more effective than sampling of brood. Brood sampling was more effective than sampling of live bees. In colonies without sealed brood, investigations of hive debris or of live bee samples seemed approximately equally efficient. The highest correlation between sampling methods was found between daily mite downfall and mites per live bee (r=0.81) in colonies with sealed brood. During the winter, investigations of dead bees and hive debris were approximately equally efficient in detectingVarroa. 相似文献
16.
Summary The production of somatic embryos from carrot suspension cultures invariably decreases through simple, repeated subculturing.
Extracellular, concentrated compounds extracted from already established embryo culture not only recovered the embryogenic
capability, but also accelerated the embryo production as much as two-fold (up to 1600 embryos/ml) compared with that of a
control culture. Sugars, which were only a small portion of the total concentrate, were excluded as possible causative factors.
It is likely that a protein fraction that is generated directly by competent, embryogenic cultures is important for the restoration
of embryogenic potential. 相似文献
17.
18.
Extracellular Overflow of Neuroactive Amino Acids During Severe Insulin-Induced Hypoglycemia: In Vivo Dialysis of the Rat Hippocampus 总被引:21,自引:11,他引:10
Hypoglycemia-evoked changes in levels of extracellular excitatory and inhibitory amino acids were studied using the microdialysis technique. A newly designed dialysis probe was inserted stereotaxically into the rat hippocampus. Animals were then subjected to insulin-induced hypoglycemia; then blood glucose levels were restored by glucose injections after a 30-min period of isoelectric electroencephalography. Dialysates were collected before, during, and after the isoelectric period. Amino acids in the dialysates were analyzed by liquid chromatography and fluorescence detection following automatic precolumn derivatization with o-phthaldialdehyde. During the isoelectric phase, the concentration of aspartate increased 15-fold, whereas glutamate, gamma-amino-butyric acid, taurine, and phosphoethanolamine levels were elevated three- to sixfold. Smaller increases were observed for nonneuroactive amino acids such as asparagine, alanine, and phenylalanine. In contrast to all other amino acids, the glutamine content was reduced to less than 30% of preisoelectric values. The concentrations of the neuroactive amino acids were restored to normal in the post-isoelectric phase. These data demonstrate that there is an extracellular overflow of neuroactive amino acids, especially aspartate, during severe hypoglycemia. 相似文献
19.
Summary It is believed that all present-day organisms descended from a common cellular ancestor. Such a cell must have evolved from more primitive and simpler precursors, but neither their organization nor the route such evolution took are accessible to the molecular techniques available today. We propose a mechanism, based on functional properties of enzymes and the kinetics of growth, which allows us to reconstruct the general course of early enzyme evolution. A precursor cell containing very few multifunctional enzymes with low catalytic activities is shown to lead inevitably to descendants with a large number of differentiated monofunctional enzymes with high turnover numbers. Mutation and natural selection for faster growth are shown to be the only conditions necessary for such a change to have occurred. 相似文献
20.
Isaksson Axel Philips Anna–Carin Göransson Eva Björkenfeldt Henrik 《Acta veterinaria Scandinavica》1987,28(3-4):455-457
The electrical conductivity (EC) of milk is mainly a function of the electrolyte concentration in the milk and therefore raised in mastitis. The present investigation was aimed at elaborating, if possible, a diagnostic model for screening purposes based on EC determinations and consistent with the diagnostic procedures and interpretations commonly used in laboratory milk diagnosis in the Nordic countries (Klastrup 1975). According to this diagnosis (here called reference diagnosis) cell numbers above 300,000/ml (cell count or the corresponding CMT-score) in foremilk quarter samples during the main part of the lactation period and significantly above the lowest value on within-udder comparison during late lactation are considered indicative of mastitis and bacteriological examinations are made when called for. 相似文献