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691.
J Matúz 《Acta physiologica Hungarica》1992,80(1-4):189-194
Gastrointestinal mucus is considered an important part of the mucosal defence mechanism against endogenous aggressors such as acid and pepsin. The mucus gel layer, adherent to the mucosal surface creates a diffusion barrier to luminal pepsin, thus protecting the underlying epithelium from the digestion by pepsin. The mucolytic pepsin will, however, digest the mucus at its luminal surface, but that lost is normally balanced by secretion of new mucus. This dynamic balance is disrupted when the mucus is exposed to excess pepsin, which causes focal haemorrhagic damage by progressively hydrolyzing the adherent mucus. The adherent mucus gel layer cannot contribute to the protection against exogen damaging agents such as ethanol and nonsteroidal anti-inflammatory drugs, as these compounds easily penetrate the mucus barrier causing, at high concentration, epithelial exfoliation. This study describes the basic properties and characteristics of gastric mucus and compares the pepsin-induced damage with the ethanol damage model. 相似文献
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694.
Interferon-γ (IFNγ) is a potent immunomodulatory cytokine. However, the early mechanisms which mediate the pleiotropic effects of IFNγ on different cells are as yet poorly understood. Therefore, we tested the role of tyrosine phosphorylation in signalling induced by IFNγ. IFNγ was found to induce rapid tyrosine phosphorylation of several proteins in HL-60 cells. This effect was detectable by 2 min, reached a maximum by about 4–16 min and thereafter declined. Tyrosine phosphorylation was dependent on receptor occupation and was maximally stimulated by 10 ng/ml IFNγ. Treatment of HL-60 cells with the tyrosine kinase inhibitors, genistein and herbimycin A, inhibited both IFNγ-stimulated tyrosine phosphorylation and IFNγ-induced Fc receptor expression. Thus, increased tyrosine phosphorylation appears to be an obligatory early and proximal signal mediating at least some of the later cellular responses induced by IFNγ in HL-60 cells. 相似文献
695.
Microbial products are surveyed that have an immunoregulatory activity, both from the realm of low-molar-mass compounds and
from the group of naturally occurring polymers. The data include in most cases the producer organism or source, a brief chemical
characteristic and biological activity. Various groups of substances are compared, the drawbacks attendant on their acquisition
and application are pointed out and their advantageous properties are specified.
Translated by K. Sigler 相似文献
696.
The characterization and distribution of the microfacies and the microfossil assemblages of a Middle Oxfordian section from
Jura Mountains composed by thick oolitic–coral limestones is analyzed. Six microfacies types (mainly grainstones) are differentiated
mainly composed by ooids, intraclasts and bioclasts. Foraminiferal assemblages are dominated by agglutinated forms. Benthic
microbial communities and sessile foraminifera are the main components of the encrustations. The whole set of microfossil
assemblages is typical of shallow subtidal environments rich in “algae” (Cayeuxia, “Solenopora”, Thaumatoporella, Bacinella, Girvanella and Terquemella) and foraminifera such as Nautiloculina oolithica, Redmondoides lugeoni, Ammobaculites coprolitiformis, Troglotella incrustans and Rectocyclammina. The increasing upward record of debris of algae and Nautiloculina, and the decrease of serpulids, bryozoans, nodosariids and ophthalmidiids indicate a shallowing-upward trend. The stratigraphic
distribution of microfacies and microfossil assemblages lead to differentiate two main successive phases. The first is a deeper
subtidal environment in an open shelf, while the second is a shallow subtidal environment with evolution from winnowed to
more restricted conditions. Microfabrics of radial to concentric ooids upwards in the section correspond to higher energy
environments related to an oolitic shoal. This study shows how a very detailed analysis of microfacies, which integrates oolitic
features, microfossil assemblages and microtaphonomy is potentially a useful tool for interpreting hydrodynamism and sequence
evolution in marine carbonate shallow environments. 相似文献
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698.
M Penka M Parízek F Mat?ja P Kubisz 《Folia haematologica (Leipzig, Germany : 1928)》1988,115(3):265-268
The coagulation inhibitors are important components of control mechanisms which ensure the haemocoagulation equilibrium. One of them is protein C, whose level was followed in patients with DIC. and IM. In DIC. cases a significant decrease was noted with regard to the MI groups and healthy donors. EID and ELISA methods were used for testing. The patients exhibiting the protein C defect require a corresponding treatment which should suppress the thromboembolic complications. 相似文献
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