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121.
Proteolysis and myelin breakdown: a review of recent histochemical and biochemical studies 总被引:9,自引:0,他引:9
Synopsis Proteins are important constituents of the myelin sheath and serve to maintain its structural integrity. One of the protein components is susceptible to tryptic digestion and may be regarded as a particularly vulnerable part of the myelin sheath. The initial events in myelin breakdown may involve disruption of lipid-protein attachments followed later by chemical degradation of released lipids.In Wallerian degeneration the activity of proteolytic enzymes increases by 12 hr after nerve section. Proteolytic enzyme activity increases in the prodromal phase of diphtheritic neuropathy. Extracts of degenerating nerve cause proteolysis of normal myelin with loss of trypanophilic basic protein and lipid; selective loss of basic protein occurs very early in Wallerian degeneration and has also been found in and around plaques of multiple sclerosis. Proteolytic activity is increased at the edges of active multiple sclerosis lesions. It has been shown that the basic encephalitogenic protein is susceptible to digestion by neural proteases, yielding an active encephalitogenic fragment.It is inferred from these collective observations that proteases play an important role in early myelin breakdown and may also be implicated in the pathogenesis of multiple sclerosis plaques by digesting basic protein, by releasing lipid from its attachment to such protein, and by liberating an active encephalitogenic peptide. The factors responsible for the activation and release of proteases remain unknown.Research Associate supported by the Multiple Sclerosis Society. 相似文献
122.
The fixing-staining mixture consisted of 1 part of 2% aqueous OsO4 and 3 parts of 3% Nal in distilled water. Fresh lungs were cut into 2 mm slices and immersed in this solution for 24 hr at room temperature. Controls were fixed in buffered OsO4 alone. Selective staining of type II alveolar cells was shown by the OsOt-NaI mixture but was absent in the controls. No additional staining of the sections was required, and the selectivity was readily observable in either paraffin or Araldite sections by light microscopy and in Araldite sections by electron microscopy 相似文献
123.
SYNOPSIS Plasmodium gonatodi sp. nov. is described from Gonatodes albogularis fuscus of eastern Panama. It is characterized by elongate gametocytes and polymorphic schizonts containing 12-46 nuclei when apparently mature. Both proerythrocytes and erythrocytes are commonly parasitized, host cells are hypertrophied and distorted, and their nuclei are displaced. Prematuration sexual stages may be irregularly shaped and larger than mature gametocytes.
Plasmodium diploglossi Aragão and Neiva , 1909 is reported from Mabuya mabouya in eastern Panama, and Plasmodium morulum sp. nov. is described from this host. P. morulum usually parasitizes immature erythrocytes, and is characterized by lenticular or oval to round gametocytes, and schizonts with 14-40 nuclei usually arranged in a globular mass. Host cells are slightly hypertrophied and distorted, and their nuclei are usually displaced. Inoculation of infected blood into clean hosts produces numerous schizonts in white cells as well as in the erythrocyte series.
Pigment in both P. gonatodi and P. morulum , if present, consists of a few minute dark dots which do not meet the polarized light test for hemozoin. 相似文献
Plasmodium diploglossi Aragão and Neiva , 1909 is reported from Mabuya mabouya in eastern Panama, and Plasmodium morulum sp. nov. is described from this host. P. morulum usually parasitizes immature erythrocytes, and is characterized by lenticular or oval to round gametocytes, and schizonts with 14-40 nuclei usually arranged in a globular mass. Host cells are slightly hypertrophied and distorted, and their nuclei are usually displaced. Inoculation of infected blood into clean hosts produces numerous schizonts in white cells as well as in the erythrocyte series.
Pigment in both P. gonatodi and P. morulum , if present, consists of a few minute dark dots which do not meet the polarized light test for hemozoin. 相似文献
124.
Developmental potential of single blastomeres of the rabbit egg 总被引:2,自引:0,他引:2
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126.
A new glycolipid sulfate ester in Halobacterium cutirubrum 总被引:7,自引:0,他引:7
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128.
Partitioning of respiratory flow resistance in man 总被引:9,自引:0,他引:9
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130.