摘要:

Several investigators have recently presented ultrastructural evidence for remodelling in the mammalian, including human, choriocapillaris. This evidence consists of cytoplasmic processes off endothelium and pericytes that penetrate the basal lamina of the capillary and enter the pericapillary space and redundant layers of basal lamina interpreted as the result of secretory activity subsequent to cellular movement within the wall of the capillary. This report extends these observations to the remaining microvasculature of the choroid – its arterioles and venules – and to another part of the ocular microvasculature – the pars plana of the ciliary body – of the rabbit and human eye. Cytoplasmic processes and redundant basal laminae were observed in the microvasculature at both sites, most frequently associated with venules and capillaries. Cytoplasmic processes and redundant basal laminae are generally associated with cellular movement and vessel growth during ocular neovascularization. However, their presence in histologically normal eyes suggests that these phenomena occur in the absence of neovascularization i. e. that the microvasculature is remodelled in the nor

ISSN:1422-6405    

DOI:10.1159/000146924

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Following a single-dose (15 mg/kg) administration of cyclophosphamide on day 12 of gestation to Wistar rats, fetuses were collected at various intervals of time and studied under the scanning electron microscope. Comparisons were made with age-matched controls. Disorganization of the neuro-epithelium (NE) was characterized by expansion of the intercellular space (ICS), appearance of abundant cellular debris, extravascular red blood cells and formation of haemorrhagic cysts in the subependymal zone. Proliferation of the choroid plexus and its surface modifications parallelled the changes in the NE. The ventricular system dilated progressively. Supra-ependymal elements appeared earlier and in greater abundance in the experimental than in the control embryos. The mesenchymal cells of the cyclophosphamide-treated embryos were scanty, poorly organized, had less numerous cytoplasmic processes than the corresponding controls and failed to develop into the primordium of the skull vault. Degenerative changes in the NE, ventricular dilatation and the absence of a supporting skull vault primordium appeared to underlie the reopening of the closed neural tube.

ISSN:1422-6405    

DOI:10.1159/000146925

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

The ligamentum infundibulo-cornuale (LIC) in the pig runs along the anterolateral side of the tubal isthmus, connecting the uterotubal junction and the edge of the infundibulum and has a comparatively well-developed muscular component running under the mesothelium. The well-vascularized smooth muscle cells held close cell-to-cell contacts and received innervation by adrenergic and cholinergic-like nerve terminals. Isolated LIC preparations, collected during oestrus showed a rhythmic spontaneous motility in vitro, the frequency and the relative amplitude of the contractions being highest during the preovulatory period. In vitro, noradrenaline and adrenaline elicited contractile (α) and relaxatory (β) responses, while isoprenaline induced only β-responses, as demonstrated by pretreatment with selective blockers. Oxytocin, PGF2cΔ and PGE2 always increased the muscular activity of the LIC. Indomethacin inhibited, in a concentration-dependent and reversible manner, the spontaneous motility of the porcine LIC, which could be fully restored by PGF2α, indicating an endogenous local synthesis of prostaglandins in the tissue. The present results suggest that, in the pig, the LIC consists of a well-arranged, richly innervated bulk of smooth muscle which shows rhythmic spontaneous activity at the time of ovulation that could assist ova pic

ISSN:1422-6405    

DOI:10.1159/000146926

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Chlorpromazine (CPZ) administration resulted in an increase in acid phosphatase (AcP) activity in the lamina VI of the neocortex pyramidal cell layer granular cell layer and hilus of the hippocampal formation. Diazepam (DZ) administration also induced an increase in AcP activity in the lamina VI of the neocortex and in the pyramidal cell layer of the hippocampal formation. The large-sized pyramidal cells of the hippocampal formation indicated a more prominent and continuous reaction in the cell processes during the administration of CPZ and DZ. The possible role of CPZ and DZ has been discussed in relation to the AcP activity in the regions studied.

ISSN:1422-6405    

DOI:10.1159/000146927

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

The distribution of tenascin, an extracellular matrix glycoprotein, and that of actin filaments were studied in the developing urethra of mouse embryos by antitenascin immunofluorescent and rhodamine-phalloidin staining. Tenascin appeared transiently in the urethral mesenchyme at the site of active morphogenesis in which the urethral epithelium separated from the surface epithelia of the glans and prepuce, being tubular, and the bilateral mesenchymes lining the preexisting urethral epithelium were seamed together in the ventral side of the tubular urethra immediately after the epithelial separation. The spatially and temporally restricted distribution of tenascin corresponded well to that of mesenchymal cells which possessed many actin filaments. These observations suggest that tenascin is involved in the cytoskeletal organization of mesenchymal cells in the active phase of morphogenesis.

ISSN:1422-6405    

DOI:10.1159/000146928

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

The presence of atrial natriuretic factor (ANF) has been demonstrated in striated myocytes of the human embryonic heart as well as in the adult heart, by immunohistochemical and immunocytochemical methods. The post-conceptional age of the embryos ranged from 8 to 9 weeks. At this early stage of development, shortly after the appearance of atrial granules in humans, ANF was localized both in the auricles and remaining parts of both atria. Immunostaining was intensified in the subendocardial areas. No immunoreactivity was observed in the developing ventricles. Immunogold electron microscopy of atrial myocytes showed that the ANF-containing atrial granules were distributed throughout the sarcoplasm, although they tended to accumulate in the paranuclear areas. Neither the Golgi apparatus nor the rough endoplasmic reticulum exhibited ANF immunoreactivity, indicating that immunoreactive ANF of the human embryonic atria is stored in the mature granules. These results indicate an endocrine function of the human embryonic atria.

ISSN:1422-6405    

DOI:10.1159/000146929

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

For access to the central venous system numerous percutaneous methods and approaches exist. Questions are often raised concerning which approach is the safest. In 18 human cadavers, we punctured the internal jugular vein via an anterior and posterior approach and the subclavian vein via an infraclavicular route to determine which of these approaches is better with respect to success rate and frequency of puncture complications. The position of the needles was assessed by dissection. Successful venipunctures were achieved in 81% by the posterior approach, as opposed to 58% by the anterior approach and the infraclavicular route. The lowest frequency of complications was attained by the posterior approach (17%) too, whereas the anterior approach (33%) and the subclavian route (25%) had higher complication rates. The main complication of posterior and anterior approaches was inadvertent arterial puncture (9 vs. 19%). At the subclavian approach puncture of a ‘wrong’ vein was frequent (14%), and the complications included a case of pleura lesion. In conclusion the posterior approach to the internal jugular vein is superior to the other investigated approaches, and therefore, it can reasonably be proposed as a usual route for the insertion of a central venous cathe

ISSN:1422-6405    

DOI:10.1159/000146930

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Effects of secondary bile acids – lithocholic (LCA) and deoxycholic (DCA) – on the in vitro development of early somite (10.5 days old) rat embryos were studied. It was shown that an addition to the culture medium of 0.1 mM LCA (final concentration) resulted in 9% growth-retarded and 12% malformed embryos when the duration of exposure was 24 h. When treatment with LCA was prolonged to 48 h, the rate of growth retardation increased to 18% and that of malformations to 40% versus 0.5% for both parameters observed in controls. This could be interpreted as a reversible or time-dependent effect of LCA on the in vitro development of the mammalian embryo. Culture of embryos in medium with 0.5 mM DCA resulted in 22% of growth retardation and 50% of malformations. DCA in 0.1 mM final concentration had only slight and statistically nonsignificant effects. Retardation of growth development could be demonstrated by a decrease in crown-rump length and the number of somites. Among malformed embryos, abnormalities in the development of the neural tube and exencephaly were the most common types of malformations. Abnormalities as well as growth retardation were accompanied by significant pathological changes in structure and perhaps in function of the endodermal visceral yolk sac cells. It could be suggested that secondary bile acids when present in pathophysiological concentrations can affect the embryonic development by direct inhibitory effects and that these effects may be time and dose depend

ISSN:1422-6405    

DOI:10.1159/000146931

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

The frequency and morphology of myoendothelial junctions occurring in human saphenous veins have been investigated. The junctions are mostly established via slender membrane projections. The junction slit is filled with a electron-dense material, sometimes forming shark-tooth-like configurations. The morphology of these hetero-cellular junctions is not compatible in all cases with gap junctions, tight junctions or desmosomes. The frequency of heterocellular junctions in endothelial cells of saphenous veins is estimated to be approximately 10 per cell, but their significance is not finally determined.

ISSN:1422-6405    

DOI:10.1159/000146932

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Corpora lutea (CL) from cows on day 12 of the oestrous cycle were studied by electron microscopy to investigate whether, and how, different subpopulations of luteal cells can be identified in tissue sections. Tissues from 6 CL were examined and nucleated profiles of luteal cells were classified as large medium or small on the basis of their areas in electron micrographs. Cut-off points for area categories for large, medium and small-sized cells were based on diameters of > 25, 20–25 and < 20 µm, respectively, if the measured areas were converted to a circular shape after correction for shrinkage. The only qualitative features which distinguished cells of large size from those of small size were the presence of clusters of secretory granules, and of exocytosis of these granules, in large cells only. However, these features were observed in only 59% of large cells, probably primarily due to sampling limitations in single sections. Other qualitative features which have been regarded as diagnostic of large or small luteal cells were observed in cells in all size categories. It was concluded that large and small luteal cells in the cyclic CL of the cow are distinguishable by their ultrastructural features. However, these data do not support the recent suggestion that the mid-cycle CL of the cow contain two subpopulations of large luteal cells in approximately equal numbe

ISSN:1422-6405    

DOI:10.1159/000146933

出版商:S. Karger AG    

年代:1990

数据来源: Karger