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101.
O. G. Belokurov S. B. Golumb N. I. Nikitina 《Bulletin of experimental biology and medicine》1976,81(4):474-476
By means of a method of two-way perfusion of the isolated human placenta the transport of urea from the fetal to the maternal placental circulation and the transport of amino acids in the opposite direction were studied. Experiments showed that the method provides for sufficiently complete perfusion of the intervillous space and creates suitable conditions for the study of placental transport. If the amino nitrogen concentrations in the two circulatory systems are equal, its concentration in the fetal circulation rises in the course of the experiment. On the addition of an amino acid to the maternal circulation, this increase develops to a greater degree. The results of these experiments confirm the view that amino acids are secreted by trophoblast cells into the fetal circulation.Laboratory of Biochemistry, Institute of Obstetrics and Gynecology, Academy of Medical Sciences of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR M. A. Petrov-Maslakov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 4, pp. 394–397, April, 1976 相似文献
102.
H. Baker R. F. Spencer 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1986,63(3):461-473
Summary The sensory neurons of the olfactory epithelium, as a consequence of their odor detection function, contact both the external environment and the central nervous system. The possibility that substances applied to the epithelium might reach the central nervous system was investigated by the intranasal application of peroxidase-conjugated wheat germ agglutinin (WGA-HRP). WGA-HRP was transported through olfactory receptor axons to the glomerulus of the olfactory bulb. Reaction product was localized electron microscopically to tubulovesicular profiles and dense bodies in sensory axons. Evidence of transneuronal transport was indicated by reaction product localized in dense bodies in dendrites postsynaptic to receptor cell axons. Periglomerular, tufted and mitral cells in the olfactory bulb also were transneuronally labeled. Anterograde transneuronal labeling occured in the olfactory tubercle, piriform cortex and surrounding the lateral olfactory tract. Retrograde transneuronal label was found in neurons of the basal forebrain with the largest number of perikarya in the lateral nucleus of the horizontal limb of the diagonal band, a major source of cholinergic afferents to the olfactory bulb. These data suggest that substances, specifically those which bind to receptors, are transported from the olfactory receptor neurons in the nasal epithelium to the brain. Thus, the olfactory system may provide a route of entry for exogenous substances to the basal forebrain.Abbreviations AC
anterior commissure
- CC
corpus callosum
- CI
internal capsule
- CP
caudate putamen
- DBB
diagonal band of Broca
- FX
fornix
- GP
globus pallidus
- IC
island of Callelae
- LV
lateral ventricle
- MS
medial septum
- OC
optic chiasm
- PIR
piriform cortex
- RF
rhinal fissure
- SON
supraoptic nucleus
- SCN
suprachiasmatic nucleus
- SM
stria medullaris
- ST
stria terminalis
- TOL
lateral olfactory tract
- TUO
olfactory tubercle
- III
third ventricle 相似文献
103.
目的:观察同型半胱氨酸(Hcy)对心肌线粒体电子漏及自由基生成的影响,以及观察牛磺酸的拮抗效应。方法: 分离大鼠心肌线粒体,超声波破碎线粒体制备亚线粒体,纯化制备猪心肌线粒体琥珀酸细胞色素C还原酶(SCR)重组体。分别用Hcy和/或牛磺酸共同孵育心肌线粒体、亚线粒体、SCR;用化学发光法测定H2O2- 及O2- 生成;并用滤膜抽滤法观察线粒体膜牛磺酸转运体的性质及Hcy对牛磺酸转运功能的影响。结果: Hcy呈浓度依赖性地刺激大鼠心肌线粒体、亚线粒体氧自由基生成及SCR电子漏增加,牛磺酸自身不影响心肌线粒体、亚线粒体及SCR氧自由基生成,但呈浓度依赖性地抑制Hcy诱导的线粒体、亚线粒体及呼吸链重组体氧自由基生成。线粒体膜上存在Na+依赖性的牛磺酸转运体,Hcy呈浓度依赖性地抑制牛磺酸转运体对牛磺酸的转运功能。结论: 牛磺酸抑制Hcy刺激的线粒体呼吸链电子漏增加及氧自由基生成。线粒体膜上存在Na+依赖性的牛磺酸转运体,Hcy抑制线粒体膜上牛磺酸转运体对牛磺酸的转运功能。 相似文献
104.
R. Stoll R. Kinne H. Murer H. Fleisch J. -P. Bonjour 《Pflügers Archiv : European journal of physiology》1979,380(1):47-52
In the present work we have investigated whether the changes in the renal handling of inorganic phosphate (Pi) induced by 1) dietary Pi, 2) removal of parathyroid glands and 3) 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], are associated with alterations in the Na-dependent Pi uptake by brush border membrane vesicles (BBMV) isolated from renal cortex. Shamoperated (SHAM) or thyroparathyroidectomized (TPTX) rats treated or not with 26 pmol/day of 1,25 (OH)2D3i.p. were fed low (0.2%) or high (1.2%)P diet for 7 days. The results showed that in SHAM, TPTX and TPTX+1,25 (OH)2D3 the Pi uptake by BBMV was greater after low than high Pi diet. It was greater in TPTX than in SHAM counterparts fed either diets. In TPTX fed low or high Pi diet 1,25 (OH)2D3 decreased the Pi uptake to the level observed in SHAM. A striking parallelism was found between variations in Pi uptake by BBMV and in the tubular Pi reabsorption of the whole kidney. The Na-dependent glucose, the mannitol uptake by BBMV, and the alkaline phosphatase activity in cortical homogenates and BBMV were not affected by the various treatments. Thus, dietary Pi, chronic TPTX and 1,25 (OH)2D3 appear to specifically affect the Na-dependent Pi transport system bound to the brush border membranes of renal cortical tubules. The alterations observed at this membrane level could account, at least in part, for the changes induced by these three factors on the overall tubular reabsorption of Pi. 相似文献
105.
E. Dietrichs 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1981,44(3):235-242
Summary The cerebellar parafloccular corticonuclear and nucleocortical connections were studied in the cat by means of anterograde and retrograde transport of horseradish peroxidase.Previous investigations have given evidence that the cortex of the paraflocculus can be subdivided into three zones. These zones are recognized as C2, D1 and D2. The material presented is compatible with the findings from previous reports with other methods that each of these zones sends its Purkinje axons to separate regions within the cerebellar nuclei. These terminal fields are the lateral part of nucleus interpositus posterior (the alleged nuclear zone C2) and the dentate nucleus and its transition area with nucleus interpositus anterior (the supposed nuclear D zones). The parafloccular corticonuclear fibres appear to terminate along a continuous mediolateral band extending from the NL through the NL-NIA transition area into the lateral NIP. This observation is in concordance with our previous findings concerning the termination of the cerebellar corticonuclear fibres (Dietrichs and Walberg 1979, 1980; Dietrichs 1981). Within the NL and NL-NIA transition area the Purkinje axons from the ventral paraflocculus terminate ventral to those from the dorsal paraflocculus.The nucleocortical projection shows the same zonal arrangement as the corticonuclear connection, indicating the presence of a corticonuclear-nucleocortical reciprocity.The findings are discussed with reference to previous studies on the parafloccular corticonuclear and nucleocortical connections, and some comments are made concerning the cerebellar zonal subdivision of this cortical area. 相似文献
106.
107.
A time-dependent loss of retrograde transport ability in distally axotomized rubrospinal neurons 总被引:1,自引:0,他引:1
Studies on the effect of axotomy on adult intrinsic central projection neurons have generally assumed that the severed proximal axonal stumps were still capable of retrogradely transporting tracer at varying times after injury. Failure of transport was interpreted as neuronal death, which is at odds with current understanding that central projection neurons survive distal axotomy. We used lumbar spinal cord-projecting rubrospinal neurons of the rat as a model to evaluate the ability of injured neurons to transport tracer retrogradely at different times after distal axotomy. We examined only the caudal part of the red nucleus, since rubrospinal neurons are concentrated here. In control animals, tracer applied to the rubrospinal tract at the T10 vertebral level labeled ventrolateral rubral neurons, while C3 application marked all rubral neurons. From 3 days after a T10 axotomy and tracer application, most ventrolateral neurons were no longer labeled by another tracer application at the C3 vertebral level via an axonal cut. The phenomenon was not caused by tracer toxicity, since a T10 tractotomy without tracer application also prevented these axotomized neurons from being labeled when treated similarly. Thus, neuronal retrograde transport capability was seriously retarded 3 days after a distal axotomy. Loss of retrograde transport may merely suggest that a mechanism no longer in service has been switched off, or perhaps it may insulate injured neurons from the effect of lesion site-derived factors. Using this property, we were able to localize cervical spinal cord-projecting rubrospinal neurons in the caudal red nucleus. Results show that although they concentrate in the dorsomedial region, some neurons were found to extend into the ventrolateral part of the nucleus. 相似文献
108.
G. A. Cherednichenko A. A. Moibenko I. A. Butovich S. A. Ogii 《Bulletin of experimental biology and medicine》1995,120(3):895-897
In thisin vitro study using a purified sarcolemmic fraction of guinea pig myocardium, the 13(S)-hydroperoxide of linoleic acid (13-HPODE)
increased in a dose-dependent manner the permeability of myocardial sarcolemma to Ca ions in concentrations above 10 μmol/liter,
stimulated Na/Ca exchange there in concentrations from 0.1 to 10 μmol/liter, and exerted a digitalis-like action on sarcolemmic
Na,K-ATPase in concentrations between 0.1 and 100 μmol/liter (IC50=20 μmol/liter). The results indicate that the linoleic acid hydroperoxide may be an effective modulator of sarcolemmic Ca2+ transport and of membrane-bound enzymes.
Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N
o
9, pp. 255–257, September, 1995
Presented by D. F. Chebotarev, Member of the Russian Academy of Medical Sciences 相似文献
109.
The fine structure and histochemistry of human bile duct in obstruction and choledocholithiasis 总被引:1,自引:0,他引:1
Biopsies from the common bile ducts from seven patients undergoing surgery for biliary obstruction due to stones or malignancy were studied histochemically and electron microscopically. The surface of the bile duct is lined by a tall epithelium which extends into diverticula. Apically, they contain some neutral and sialated mucosubstances. Fucosyl residues were found in the Golgi apparatus and along the apical cell membrane. The latter is lined by microvilli. There was a well-developed rough endoplasmic reticulum and Golgi apparatus and a small number of apical secretory droplets. Large numbers of lipid droplets were present basally in some cells. Lipid-containing macrophages were also seen intra-epithelially and in the lamina propria. This suggests a possible pathway for lipid transport. The glands were lined by cuboidal cells, some containing much mucus--sulphated, sialated, and neutral with a basal nucleus. A well-developed endoplasmic reticulum and Golgi apparatus were found with abundant secretory droplets. The glandular epithelium contained lysozyme, alpha-1-antitrypsin, and alpha-1-antichymotrypsin. These may play a protective role. The lamina propria contained scattered smooth muscle cells amongst the fibroblasts and inflammatory cells. 相似文献
110.
Yuichi Majima David L. Swift Betsy G. Bang Frederik B. Bang 《Annals of biomedical engineering》1985,13(6):515-530
Responses of nasal mucociliary transport mechanisms to exposure to 6 ppm SO2 were studied in chickens in vivo. This model takes advantage of the natural cleft palate which exposes the mucociliated base
of the nasal septum. Exposure to 6 ppm SO2 decreased the mucociliary transport rate along the base of the nasal septum. The minimum force required to move an iron particle
along this area of mucous membrane by use of a magnetic field in vivo increased significantly after SO2 exposure, while the minimum force required to move an iron particle on a pool of mucus collected from the same chicken and
tested in vitro showed no change after SO2 exposure. The elastic recoil distance of mucus was measured both in vivo and in vitro. The in vivo recoil distance decreased
significantly after SO2 exposure, while SO2 exposure did not change recoil distance in vitro. It is proposed that exposure of chickens to SO2 results in the formation of multiple points of adhesion of strands of mucus between the acinar gland cells and the emergent
extracellular mucus or adhesion of a mucous blanket to the cilia, causing mucociliary transport to be retarded or static. 相似文献