摘要:

The studies were carried out on 100 right lungs taken from dead human bodies of both sexes whose age varied from 16 to 81 years. The pulmonary artery and the bronchus were injected with a 65% solution of duracryl and then digested in sul furic acid. The specimens obtained were then examined to determine the number and dimensions of the branches of the basal portion of the right pulmonani artery (RPA) penetrating into the basal segments of the right lower pulmonan lobe. Their length was 52 mm at the most, and their diameter 14 mm. Three types of ramification of the basal portion of the RPA were distinguished on the basis of the trunks, segmental and subsegmental branches present. In 72% of the cases the branches penetrating into the basal segments showed a tree-like type. in 2% of the cases a bushy-like type and in 26% of the cases a middle type.

ISSN:1422-6405    

DOI:10.1159/000147373

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The chorioallantoic placental interhemal membrane of Miniopterus schreibersii fuliginosus has been described electron-microscopically. Morphologically thereare three main types of placentae which develop in chronological sequence. They are (1) primary placenta, (2) secondary placenta and (3) tertiary placenta. In neural groove and limb-bud embryos the primary placenta consists of the following elements which separate the maternal and fetal circulations: (1) a continuous ectoplasmic layer, (2) intrasyncytial lamina, (3) syncytiotrophoblast, (4) cytotrophoblast, (5) basal lamina, (6) mesenchyme and (7) fetal endothelium. The primary placenta degenerates until term when it consists of a thin syncytiotrophoblastic layer resting on basal lamina. Mesenchyme does not show the presence of fetal capillaries. The secondary placenta is formed in early limb-bud embryos. The electron microscope has revealed that the placenta is of the endotheliomonochorial type and (1) consists of a well-developed maternal endothelium, (2) the trophoblast surrounding the maternal blood tubule is cellu lar, not syncytial as previously thought and the apical plasma membrane of these trophoblastic cells is in direct contact with the discontinuous interstitial membrane, (3) basal lamina, (4) mesenchyme and (5) fetal endothelium. Tertiary placenta at full term stage is of the hemodichorial type having the following elements: (1) thin ectoplasmic layer, (2) a thick intrasyncytial lamina, (3) syncytiotrophoblast, (4) cytotrophoblast, (5) basal lamina, (6) mesenchyme and (7) fetal endothelium. The definitive chorioallantoic placental barrier in this bat thus differs from the organization earlier proposed by Chari and Gopalakrishna [Proc. Indian Acad. Sci. 93: 463-483, 1984] on the basis of light-microscopic observations: (1) the absence of maternal endothelium in the primary placenta from the neural groove and early limb-bud embryos, (2) the existence of only cellular trophoblast in the secondary placenta throughout the gestation and (3) the presence of well-developed hemodichorial tertiary placenta is the unique feature of the interhemal membrane in higher Chiroptera.

ISSN:1422-6405    

DOI:10.1159/000147374

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

In vivo effects of fibroblast growth factor (FGF) on osteogenesis were evaluated in the chick embryo. Autoradiographic studies of Η-proline labeling over bone matrix indicated that 24 h after treatment on day 11, FGF stimulated osteogenic cell proliferation, while inhibiting the production of bone matrix collagen. However, 4 days after multiple doses of FGF, the large pool of newly formed osteogenic and chondrogenic cells expressed their function with the increased formation of matrix. The data provide in vivo evidence of the effects of exogenous FGF on osteogenesis and also point to a possible role for FGF both in embryonic osteogenesis and in fracture repair

ISSN:1422-6405    

DOI:10.1159/000147375

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

We analyzed the distribution and labeling patterns of troponin-T, a protein involved in the regulation of striated muscle contraction, in myocardiocytes obtained from chick embryos in Hamburger and Hamilton’s stage 25 and 39, and cultured for 8 days. Troponin-T expression was examined with indirect immunofluorescence, densitometry, fluorescence-activated cell sorting, electrophoresis and immunoblotting. The patterns of expression of troponin-T were compared with those of actin to determine possible correlations in different stages of chick embryo development and culture. Our findings show that in both stages of embryonic development, the cellular accumulation of troponin-T changed after 8 days of culture. Our results revealed a quantitative modification with time: after 4 days of culture there was a significant increase in this protein, followed by a slight additional increase after 8 days of culture. Flow cytometry findings confirmed these trends over time, showing a significant increase in positive cells after 4 days, followed by a smaller rise after 8 days of culture. In comparison with actin, this pattern was similar only in cells from Hamburger and Hamilton’s stage 25 embr

ISSN:1422-6405    

DOI:10.1159/000147376

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Mineralization at collagen fibrils is regulated by glycosaminoglycans (GAG). Alterations in proteoglycan composition during mineralization as well as inhibition of mineralization by GAGs are well documented. Collagen-GAG interactions during desmoid osteogenesis in fetal rat calvariae were investigated ultrastructurally by means of different fixation techniques. Mineralization was restricted to the collagen of the osteoid at the ectocranial side. Beyond the osteoid, one layer containing degenerated cells was found, followed by sheets of healthy osteoblasts with nonmineralized collagen fibrils. These fibrils were ordered in bundles, but were irregularly arranged in the mineralized osteoid. After fixation in glutaraldehy deruthenium red (GA-RR), small RR-positive granules were periodically attached to the fibrils of the nonmineralized collagen. These granules were absent at collagen in the mineralized osteoid. Periodically bound granules (periodicity of 62 nm) could clearly be demonstrated along collagen fibrils by pretreatment with the positively charged protamine sulfate and subsequent fixation in GA-RR in the nonmineralized collagen. In the mineralized osteoid, however, these granules were present, but periodic binding was missing. Heparin pretreatment followed by fixation in GA-RR revealed periodically bound fine strands between collagen fibrils running parallel in the nonmineralized collagen; these threads were absent in the mineralizing osteoid. Restriction of mineralization to osteoid at the mineralization border may be reflected by the observed changes in GAG binding to collagen fibrils within the osteoid of developing fetal calvariae in contrast to binding to collagen in nonmineralized areas.

ISSN:1422-6405    

DOI:10.1159/000147377

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Thymic innervation has been quantified using silver impregnation and light microscopy on 5 juvenile and 5 aged rats. There is an increase in innervation density of the thymus with age, exceeding the reduction of thymic volume due to involution. The density of innervation correlates inversely with thymic volume. From previous studies, we conclude that thymic innervation is confined to the extraparenchymal compartment. Ultrastructural morphometry shows this compartment to maintain its volume during involution of the remaining thymic tissue. Related only to the extraparenchymal compartment, the innervation increases by a factor two with age.

ISSN:1422-6405    

DOI:10.1159/000147378

出版商:S. Karger AG    

年代:1992

数据来源: Karger