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1.
The number of mast cells in connective tissue from dorsal skin varied markedly among mouse strains. Inbred strains of mice were typed into three groups, high (NC and NZB mice), low (B6, B10, and BALB/c mice), and intermediate (C3H/He and DBA/2 mice), by their mast cell content in the skin. However, the strain differences in the number of mast cells was marginal at the age of weaning but became distinct with age. This could be explained mainly by the frequently observed clustering of mast cells in adult NC and NZB mice and the rarely observed clustering in younger mice as well as in adult B10 and BALB/c mice. The breeding experiment revealed that the difference in the number of mast cells between NC and B10 mice was controlled by a single autosomal dominant locus, for which we propose the designation Mcr (mast cell regulator). The role of the Mcr locus with regard to the frequency of the mast cell population in connective tissue is discussed. 相似文献
2.
Summary Chitin--chymotrypsin complex was found to be an effective catalyst for the esterification of N-acetyl-L-tryptophan in ethanol and for peptide synthesis from N-acetyl-L-tyrosine and glycinamide in acetonitrile. In the former reaction both initial rate of ester formation and equilibrium yield of the ester markedly increased by the complexation of chymotrypsin with chitin compared to free chymotrypsin. 相似文献
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Although the optimum substrate for lipoamidase (lipoyl-X hydrolase) has not yet been determined, it is known that lipoamidase activity, as determined by hydrolysis of the synthetic substrate lipoyl 4-aminobenzoate (LPAB), is widely distributed in pig brain tissues, i.e. in the cerebrum, cerebellum and medulla. Over 95% of the enzyme activity is present in the membrane subfractions, indicating that brain lipoamidase is an integral membrane protein enzyme. To elucidate the chemical nature and the optimum substrate of the abundant lipoamidase in the brain, we isolated it from the membrane subfractions. After an 8-step purification procedure, brain lipoamidase was purified 601-fold and identified as a 140 kDa glycoprotein by SDS/PAGE. A mechanistic study to determine Km and Vmax, values was carried out using various synthetic compounds. Lipoyl-lysine, which is generally believed to be a naturally occurring substrate of lipoamidase, was first compared with biotinyl-lysine, because these two vitamins have reactive sulphur atoms and are similar in molecular mass and structure. The Km for lipoyl-lysine was 333 microM, whereas biotinyl-lysine was not hydrolysed. Stringent specificity for the lipoyl moiety is demonstrated, as expected. Dipeptides of amino acid-lysine structures were studied, and dipeptides of aspartyl- and glutamyl-lysine hydrolysis occurred at high Km (3 mM) values. Thus lysine in the moiety is not very effective as an optimum substrate. The chemical bond structures of the amide bond (lipoyl-lysine) and peptide bond (aspartyl-lysine) were hydrolysed. Next, the ester bond compound was tested, and it was observed that lipolylmethyl ester was hydrolysed at high specificity. These findings indicate that this enzyme has broad specificities with respect to bond structure; it therefore is a unique hydrolase having stringent specificity for lipoic acid and relatively broad specificity for the chemical bond and the X moiety. Various inhibitors were tested; a few reagents, such as organic mercurials, di-isopropylfluorophosphate, 1,10-phenanthroline, sodium azide and angiotensin-converting enzyme inhibitor exhibited some inhibition (not more than 60%). Thus the active centre of this enzyme is a complex type. Although ATP is not hydrolysed and the lowest Km value is exhibited by the synthetic substrate reduced from LPAB (12 microM), some other compounds may still be expected to be hydrolysed by this unique and abundant brain lipoamidase. 相似文献
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Accumulation of collagen III at the cleft points of developing mouse submandibular epithelium 总被引:7,自引:0,他引:7
Y Nakanishi H Nogawa Y Hashimoto J Kishi T Hayakawa 《Development (Cambridge, England)》1988,104(1):51-59
The distribution of collagens I, III, IV and V was studied by immunoperoxidase staining of early developing mouse submandibular glands. Collagen I was always present in the extracellular matrices of the mesenchyme and at the epithelial-mesenchymal interfaces of the 12-day gland with no clefts and of the 13-day gland with a few definite clefts. Collagen III was found in a similar fashion to that of collagen I in the mesenchyme, but the distribution at the epithelial-mesenchymal interfaces was very different. In the mid 12-day gland with a round lobule, collagen III was distributed at every slightly indented site of basal epithelial surfaces. At the late 12-day stage, a few initial signs of cleft appeared on the surface, at which accumulation of collagen III became evident. Intense immunoreaction of collagen III in the early 13-day gland was seen at the bottom of every narrow cleft. No specific accumulation of collagens IV and V was observed in clefts of the late 12-day and early 13-day glands. Staining of collagen III in the 12-day gland cultured for 10 h in the presence of bovine dental pulp collagenase inhibitor, which has been shown to stimulate cleft initiation, was very prominent at the bottom of every narrow cleft. These observations suggest that collagen III works as a key substance for either in vitro or in vivo cleft initiation of the mouse embryonic submandibular epithelium. 相似文献
7.
The role of interstitial collagens in cleft formation of mouse embryonic submandibular gland during initial branching 总被引:8,自引:0,他引:8
Y Fukuda Y Masuda J Kishi Y Hashimoto T Hayakawa H Nogawa Y Nakanishi 《Development (Cambridge, England)》1988,103(2):259-267
An interstitial collagenase was purified from the explant medium of bovine dental pulp and was shown to degrade collagens I and III but not IV and V. The enzyme halted cleft initiation in the epithelium of 12-day mouse embryonic submandibular glands in vitro, indicating the active involvement of interstitial collagens in the branching morphogenesis. Transmission electron microscopic observation of the intact 12-day gland without any clefts showed the scattered localization of a few collagen fibrils at the epithelial-mesenchymal interface of the bulb and also revealed the presence of numerous microfibrils around the stalk. Collagen bundles were regularly seen close to the wavy basal lamina at the bottom of clefts of the intact 13-day gland and 12-day gland cultured for 17 h under normal conditions. Mesenchymal cells were found in the clefts together with the frequent localization of peripheral nerve fibres and capillary endothelial cells. The collagen bundles were more often observed in the 12-day gland cultured in the presence of bovine dental pulp collagenase inhibitor, which had been shown to enhance cleft formation. In contrast, collagen fibrils were rarely found at the epithelial-mesenchymal interface of the 12-day gland cultured in the presence of Clostridial or bovine dental pulp collagenase. The findings indicated that the formation of interstitial collagen bundles is essential to form clefts in the epithelium both in vivo and in vitro. 相似文献
8.
In vitro binding of nuclear proteins from wheat germ to the5'-upstream region of the rolC gene of Ri plasmid was investigated.The specific DNA sequences interacting with proteins were detectedby DNase I footprinting. (Received October 8, 1990; Accepted November 30, 1990) 相似文献
9.
Cervicovaginal and endometrial cytology in ovarian cancer 总被引:1,自引:0,他引:1
The clinical significance of cytologic examination was studied in 114 patients with ovarian cancer who had received preoperative cytologic examinations. The overall positive rate of the cytologic examinations was 26.3% (30 of 114): 22 (19.3%) of the 114 cases had positive cervicovaginal smears while 13 of 31 endometrial aspiration smears (41.9%) were positive. The positive rate was not related to the volume of ascites but rather to its presence or absence. Thus, if ascites was observed, the positive rate was about 2.1 times higher than if it was absent. In two of four cases of ovarian cancer with no endometrial invasion but a positive cytologic examination of ascitic fluid, fallopian tube specimens contained cancer cells; this suggests that ovarian cancer cells may reach the cervix and/or vagina by passing through the fallopian tube, particularly if ascites is present. Since cytologic examination, especially of endometrial aspiration smears, shows a high positive rate if ovarian cancer cells are observed in the abdominal cavity, cytology should be used as an important ancillary method for the assessment of ovarian cancer. 相似文献
10.
Postoperative changes in vaginal smears after vaginal reconstruction with a free skin graft 总被引:1,自引:0,他引:1
Surgical vaginal reconstruction was performed by a free skin graft in two patients without a vagina. The postoperative changes in vaginal smears collected from the artificial vaginas were observed for about two years. Marked operation-induced inflammatory changes were observed until the second postoperative month. After the third postoperative month, the background became relatively clear. Cyanophilic and eosinophilic superficial cells, intermediate cells and D?derlein bacilli were observed occasionally in addition to keratotic cells. Six to 12 months after surgery, the vaginal smears showed little abnormality, except for the presence of keratotic cells. The changes in the vaginal smears after the third month show that the artificial vaginal epithelium changed cytologically to an almost normal vaginal mucosa that, although not histologically complete, responded to hormones. The presence of D?derlein bacilli suggests that the regional environment of the artificial vagina was almost the same as that of the normal vagina. 相似文献