共查询到20条相似文献,搜索用时 7 毫秒
1.
2.
3.
D. Vincent Provenza Yung-Feng Chang Leslie P. Gartner Richard M. Garlitz 《Histochemistry and cell biology》1972,29(4):355-361
Summary Applying the ditetrazolium salt (Nitro-BT) method for succinic dehydrogenase, murine molar teeth were studied sequentially from the cap stage of development through the appositional stages of odontogenesis. Reaction-distribution and intensity varied relative to the developmental stage as well as the zone of maturation within a given stage. The peripheral cells of the parent dental lamina exhibited some activity, as did the outer enamel epithelium of the bell stage. During the period of matrix apposition, components of the stratum intermedium, ameloblastic zone and odontoblastic layer region of the dental papilla demonstrated intense enzymatic activity. Cells actively engaged in enamel matrix production demonstrated activity in the basal and distal cell segments. High activity continued in the papillary layer of the enamel organ, as well as in the cells of the dental sac during the postamelogenic period.Supported by PHS Grant No. 2800-02, National Institute of Dental Research, National Institutes of Health. 相似文献
4.
5.
Collagen formation in developing molar teeth of rats 总被引:5,自引:0,他引:5
E J Reith 《Journal of ultrastructure research》1967,21(5):383-414
6.
7.
8.
Malocclusions of the premolar and molar teeth of inbred Strain 2/N and Strain 13/N and outbred Dunkin-Harley guinea pigs were examined. A higher incidence of malocclusion observed in the inbred strains suggested a genetic basis for the disorder. 相似文献
9.
10.
11.
During development, Bone Morphogenetic Proteins (BMPs) can induce apoptosis, cell growth or differentiation. These different
effects are mediated by dimers of two types of BMP–receptors (BMPRs). To identify the responding cells during tooth development
and search for possible tissue–or stage–specificities in the receptors involved, the distribution patterns of BMPR–IA, –IB
and –II were investigated in the mouse molar, from bud to bell stage. At the bud stage, BMP–2 was suggested to be involved
in the formation of an epithelial signaling center, the primary enamel knot (PEK), while BMP–4 would mediate the condensation
of the mesenchyme. Immunostaining showed the presence of BMPR–IA and –II in the epithelium instead of BMPR–IB and –II in the
mesenchyme. At the cap stage, BMPR–IB was detected in the epithelium but not BMPR–II, suggesting the existence of another
type II receptor to form a functional dimer. At the late cap stage in the epithelium, BMP–4, BMPR–IA and –II were restricted
to the internal part of the PEK and the stalk: two apoptotic areas. The three proteins were detected in the mesenchyme, showing
a strong staining where cusps were about to form. At the late bell stage, BMP–2 or –4 may induce cell differentiation. BMPR–IB
and –II were detected in odontoblasts instead of BMPR–IA and –II in ameloblasts. These results provide the first evidence
of multiple type I and type II BMP–receptors, expressed in the dental epithelium and mesenchyme at different stages of development,
to signal different cellular activities in a time– and tissue–specific way. 相似文献
12.
13.
14.
15.
Acquired immunity to Trichuris muris in the albino laboratory mouse 总被引:14,自引:0,他引:14
D Wakelin 《Parasitology》1967,57(3):515-524
16.
17.
18.
Xie M Kobayashi I Kiyoshima T Yamaza H Honda JY Takahashi K Enoki N Akamine A Sakai H 《The Journal of biological chemistry》2007,282(32):23275-23283
We examined the functional implication of nucleolin in the mouse first molar development. Both the nucleolin mRNA and protein expressions were demonstrated in the odontogenic epithelial cells in the early stage and in the inner enamel epithelial layer in the late stage. The expression pattern of nucleolin corresponded to the proliferating cells in the tooth germ, thus showing that nucleolin could possibly be related to cell proliferation. No in situ signal of nucleolin was found in the primary enamel knot (PEK). Furthermore, nucleolin protein was demonstrated in the PEK by immunohistochemistry. The existence of nucleolin protein in the PEK may possibly be related to the apoptosis in the PEK cells. An inhibition assay using the hemagglutinating virus of Japan-liposome containing nucleolin antisense phosphorothioated oligonucleotide (AS S-ODN) in cultured mouse mandibles at embryonic day (E) 11.0 showed a marked growth inhibition of tooth germ. Moreover, no developmental arrest was found in the cultured tooth germ at E15.0 treated with nucleolin AS S-ODN. Real time PCR was performed to examine the mRNA expression of nucleolin-related genes, and a significant reduction in the midkine mRNA expression was thus observed in the mouse mandible after being treated with nucleolin AS S-ODN. This inhibition assay indicated that nucleolin could thus be involved in the early stage of tooth germ initiation and morphogenesis, possibly by regulating the midkine expression. 相似文献
19.
'Seams' of the root furcation with multiroots in rat molar teeth, termed by Lester and Boyde, were investigated using transmitted light and scanning electron microscopy in the formation process. The seam was formed in the junctional line of Hertwig's epithelial root sheaths. The seam formation will be classified into three types in the initial stage based on the position of the epithelial root sheaths approaching each other: (1) the close junction or the very narrow slit or gap formed between them, (2) the clear gap containing mesenchymal cells and (3) the gap containing one blood vessel. When the roots were formed, the seam was formed as follows: (1) the slight ridge composed of the cellular cementum, (2) the proliferation or the depression in the dentine formation and (3) the accessory or lateral canal of the root. These structures were variously combined with each other into one seam, although the slight ridge was very common. 相似文献