摘要:

The distribution of succinic dehydrogenase enzyme activity was investigated in frozen sections of longissimus dorsi muscle taken from several species of East African game animal (giraffe, hartebeest, wildebeest, oryx, gerenuk and dik-dik) as well as local zebu cattle. Muscle fibres were classified as red (high succinic dehydrogenase activity), white (low activity) or intermediate. The mean diameter and percentage distribution of each fibre type were noted as well as the overall mean muscle fibre diameter (MFD) for each species. The diameters of red muscle fibres were found to be between 54 and 62% of the diameters of the white muscle fibres for all species with MFD differences between species being up to over 100%. The variation in MFD was found to be significantly and positively correlated with live weight, when zebu values were omitted. It was found that the variation in MFD was significantly related to the diameter of muscle fibre types and not to the percent distribution of these fibre types.

ISSN:1422-6405    

DOI:10.1159/000145144

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

The electron microscope was used to examine the junctional zone of the chorioallantoic placentas of living rat young which had been experimentally retained in utero for as long as 4 days beyond delivery of their littermates. Junctional zone cells in such prolonged placentas were compared with corresponding cellular elements in term placentas. By the 1st day of the postterm period, placental glycogen cells in the junctional zone were depleted. Many trophoblast giant cells and trophospongial elements appeared fully viable throughout the entire 4-day period, however, Giant cells from placentas of prolonged pregnancy were indistinguishable from those in placentas at term. Both in term and in postterm placentas the trophospongial elements displayed a variation in the organization of the granular cisterns of endoplasmic reticulum within them. No variants appearing to prefigure involution were identified either in term or in prolonged placentas. However, more cells with vesiculate cisterns were seen in junctional zones from placentas which were retained beyond term. Intercellular relationships also were preserved during the postterm period. With the integrity of the cells of this zone so well preserved both in term and in prolonged placentas, it is concluded that parturition is not dependent on their involution.

ISSN:1422-6405    

DOI:10.1159/000145145

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Primary mineralization in healing sockets after extraction of molar teeth was studied in rats. The observations obtained by scanning electron microscopy were correlated by transmission electron microscopy. The process is characterized by abundance of extracellular matrix vesicles distributed between the forming cells and the calcifying fronts. The occurrence of osmiophilic material and solitary hydroxyapatite crystals within the vesicles was followed by accumulation of hydroxyapatite crystals, disappearance of the vesicular membrane and formation of calcospherites that conglomerate into calcified fronts. The process described here in bone healing is essentially similar to primary mineralization in other normal and pathological calcified tissues.

ISSN:1422-6405    

DOI:10.1159/000145146

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Merkel nerve endings of sinus hairs in the upper lip of the rat were observed after having cut the nervus infraorbitalis. The nerve terminal of the Merkel nerve ending has already been degenerated 24 hours after denervation and was phagocytised by neighbouring keratinocytes. The Merkel cells did not change in structure after having lost their nerve terminal even within 169 days after nerve crush. Their position in the stratum basale of the sinus hairs remained constant; the number, size and position of the osmiophilic granules in the cytoplasm of the Merkel cells did not change. These results may show, that Merkel cells are not modified keratinocytes. The possibilities of their origin are discussed.

ISSN:1422-6405    

DOI:10.1159/000145147

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

46 goat spleens were studied to observe the venous segmentation in them by preparing the corrosion cast of the splenic vein and its intrasplenic tree. 56.5% of the specimens revealed the presence of two splenic venous segments – a right and a left one - and 30.4% of cases showed the presence of three venous segments – a right, a left and a hilar one. The rest did not show any venous segmentati

ISSN:1422-6405    

DOI:10.1159/000145148

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

The aging optic nerves and visual cortices were studied in mice. Changes in the morphology of neuroglia were evident in the optic nerve but no difference in the numbers of neurotubules or myelin sheaths optic nerve fibers in the aged were observed. Large myelinated fibers, however, begun to degenerate. In the aging visual cortices, a higher proportion ofden-drodendritic contacts were present and microglia cells were found to be active.

ISSN:1422-6405    

DOI:10.1159/000145149

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

The present study reports on the effects of in vivo single and multiple isoproterenol (ISP) injections on the proliferative response of subsequently explanted mouse submandibular glands. Explants were cultured in Waymouth’s medium supplemented with 10% fetal bovine serum, and were harvested after 1 2,4 or 6 days in culture. 24 h prior to harvest, the explants were fed medium containing [3H] thymidine. At the time of harvest, the explants were fixed in situ and processed for light-microscopic radioautography. The number of labeled nuclei and the total number of nuclei were counted, and labeling indices were calculated for the control and ISP-treated explant sections. The results show that the ISP-treated explants had more cells actively synthesizing DNA than did the corresponding control explants after 1 day in culture. In addition, after 2 days in culture, the explants from mice that had received a single dose of ISP incorporated more [3H] thymidine than the corresponding control explants. These results suggest that the in vivo ISP stimulus initiated a hyperplastic response in vivo that was completed during the 1 st or 2nd day in vitr

ISSN:1422-6405    

DOI:10.1159/000145150

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

The paper deals with the histological and histoenzymological studies of the medulla oblongata of Taphozous melanopogon Temminck (a microchiropteran bat). Three phosphatases, namely acid phosphatase (ACP), thiamine pyrophosphatase (TTP) and glucose-6-phosphatase (G-6-P) were studied. All the enzymes were seen in all the neurons. The large neurons of the different nuclei are more strongly positive for ACP than the small neurons. Further, the areas which contain dense populations of neurons are more strongly stained than the area containing scattered neurons. TPP and G-6-P distributions are almost parallel to that of ACP. The functions of these enzymes in synthesis and secretory processes were discussed.

ISSN:1422-6405    

DOI:10.1159/000145151

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

The hypothalamic arcuate nucleus (ARC) was electron microscopically studied in diestrous (D) and estrous (E) mice, and mice ovariectomized (OX) 3 weeks before. In the middle region of the ARC (mARC), the number of dense core vesicles (DCVs) appearing in a section of each neuronal perikaryon was examined, and the location of the neurons containing DCVs was mapped. About 10% of the neurons in the mARC contained many (5 or more) DVCs in the perikarya in a section. These neurons mainly localized in the ventromedial portion of the mARC, which shows that the cytoarchitecture of the mouse ARC is heterogeneous. The localization and the frequency of these neurons were not influenced by the variance of ovarian activity. A DCV was composed of an electron-dense core and a membrane halo, and was likely to be formed in the cisternae of the Golgi apparatus. The size of DCVs was estimated at 100 nm as the median diameter and was stable independent of the ovarian activity. However, the formation of DCVs was likely influenced by the ovarian activity, because DCVs in D mice were more intimately associated with the Golgi apparatus than in E or OX mice. In the neuronal perikarya of the ventromedial portion of the mARC, Nissl bodies developed in OX mice, and nucleolus-like bodies developed in E mice. These results suggest that the neurons of the ventromedial portion of the mARC change their function according to the variance of ovarian activity and, therefore, are involved in the estrogen feedback mechanism.

ISSN:1422-6405    

DOI:10.1159/000145152

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

By following the development of individual mice from birth to 200 days of age, it was found that the skull of the homozygous mutant (dwdw) was 5% shorter than that of the normal phenotype at birth and some 30% shorter at 200 days of age. During post-natal growth of the skull, the cranium was least altered but the facial skeleton was greatly affected. The differences seen in different parts of the skull are attributed to the peak growth velocities of the various parts occurring at different times.

ISSN:1422-6405    

DOI:10.1159/000145153

出版商:S. Karger AG    

年代:1979

数据来源: Karger