共查询到9条相似文献,搜索用时 15 毫秒
1.
Quantitative immunogold procedure was used to study the distribution of metallothionein I/II (MT-I/II) at the ultrastructural level in the perivascular areas, including microvascular endothelial cells (ECs) and astrocytes with their perivascular end-feet, in brains of scrapie-infected hyperglycemic (diabetic) and normoglycemic (non-diabetic) mice. Samples of the fronto-parietal cortex obtained from diabetic and non-diabetic scrapie-infected, as well as from non-infected (control) SJL/J mice, were processed for immunocytochemical examination. In control mice, the labelling of the ECs was of low intensity, restricted to few immunogold particles in the cytoplasm. More intense labelling was present in the cytoplasm of astrocytic perivascular processes and perikarya, where it was associated with endoplasmic reticulum and fibrils. A few immunosignals were also present inside the nuclei of astrocytes. In diabetic mice the labelling of the EC cytoplasm was slightly increased, whereas in the cytoplasm of perivascular processes and pericarya of astrocytes, including their nuclei, there was significant enhancement of labelling. In these cells the density of immunosignals was highest in the areas of cytoplasm containing bundles of fibrils. In non-diabetic, scrapie-infected mice the intensity of immunolabelling was higher than in control mice but slightly lower than in diabetic mice. These results are similar to those in Alzheimer’s disease reported by other authors, and suggest that neurodegenerative diseases as well as metabolic stress enhance the metallothionein expression in perivascular regions of brain cerebral cortex, predominantly in astrocytes. 相似文献
2.
Immunolocalization of tight junction proteins in blood vessels in human germinal matrix and cortex 总被引:2,自引:2,他引:0
Brain development occurs in a specialized environment maintained by a blood–brain barrier (BBB). An important structural element
of the BBB is the endothelial tight junction (TJ). TJs are present during the embryonic period, but BBB impermeability accrues
over an extended gestational interval. In studies of human premature infants, we used immunomicroscopy to determine if amounts
of the TJ proteins ZO-1, claudin and occludin increase with gestational age in vessels of germinal matrix (GM) and cortex.
By 24 weeks postconception (PC), TJ proteins were present in both GM and cortical vessels, but immunoreactivity in the GM
of the youngest subjects was less than in older subjects. At 24 weeks PC, TJ protein immunoreactivity in GM vessels was less
than in cortical vessels suggesting that TJ maturation progresses along a superficial to deep brain axis. This concept correlates
with conclusions from previous analyses of the expression of brain endothelial cell alkaline phosphatase (AP) activity. AP
appears in cortical vessels before appearing in deep white matter and GM vessels. Together, these data indicate that differentiation
of some functional specializations is still in progress in GM vessels during the third trimester. This maturation could relate
to the pathogenesis of germinal matrix hemorrhage–intraventricular hemorrhage. 相似文献
3.
Suzuki T Matsunami T Hisa Y Takata K Takamatsu T Oyamada M 《Histochemistry and cell biology》2009,131(1):89-102
Despite the importance of glucose metabolism for auditory function, the mechanisms of glucose transport in the cochlea are
not completely understood. We hypothesized that gap junctions mediate intercellular glucose transport in the cochlea in cooperation
with facilitative glucose transporter 1 (GLUT1). Immunohistochemistry showed that GLUT1 and the tight junction protein occludin
were expressed in blood vessels, and GLUT1, the gap junction proteins connexin26 and connexin30, and occludin were also present
in strial basal cells in the lateral wall of the rat cochlea. Gap junctions were found among not only these GLUT1-positive
strial basal cells but also GLUT1-negative fibrocytes in the spiral ligaments and strial intermediate cells. Glucose imaging
using 6-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-6-deoxyglucose (6-NBDG, MW 342) together with Evans Blue Albumin (EBA,
MW 68,000) showed that 6-NBDG was rapidly distributed throughout the stria vascularis and spiral ligament, whereas EBA was
localized only in the vessels. The gap junctional uncouplers heptanol and carbenoxolone inhibited the distribution of 6-NBDG
in the spiral ligament without decreasing the fluorescence of EBA in the blood vessels. These findings suggest that gap junctions
mediate glucose transport from GLUT1-positive cells (strial basal cells) to GLUT1-negative cells (fibrocytes in the spiral
ligament and strial intermediate cells) in the cochlea. 相似文献
4.
Ryusuke Takechi Susan Galloway Menuka Pallebage-Gamarallage Cheryl Wellington Russell Johnsen John Charles Mamo 《Histochemistry and cell biology》2009,131(5):661-666
Parenchymal accumulation of amyloid-beta (Aβ) is a hallmark pathological feature of Alzheimer’s disease. An emerging hypothesis
is that blood-to-brain delivery of Aβ may increase with compromised blood–brain barrier integrity. In plasma, substantial
Aβ is associated with triglyceride-rich lipoproteins (TRLs) secreted by the liver and intestine. Utilizing apolipoprotein B as an exclusive marker of hepatic and intestinal TRLs, here we show utilizing an highly sensitive
3-dimensional immuno-microscopy imaging technique, that in APP/PS1 amyloid transgenic mice, concomitant with substantially
increased plasma Aβ, there is a significant colocalization of apolipoprotein B with cerebral amyloid plaque. The findings
are consistent with the possibility that circulating lipoprotein-Aβ contributes to cerebral amyloidosis. 相似文献
5.
Dr. Marijke de Jong-Brink Nico D. de With Peter J. M. Hurkmans Marion J. M. Bergamin Sassen 《Cell and tissue research》1984,235(3):593-600
Summary In the hermaphroditic pulmonate snail Lymnaea stagnalis a blood-gonad (blood-testis) barrier appears to exist. Septate junctions between Sertoli cells and epithelial cells of the neck areas of the gonadal acini constitute this barrier; they separate the male from the female compartment. Experiments with tracer substances (colloidal gold particles, lanthanum nitrate, tannic acid) showed that the basal lamina around the acini hardly forms a barrier; only the larger colloidal gold particles do not pass this lamina.Physiologically, the blood-gonad barrier is apparent in studies on the composition of gonadal fluid, which differs considerably from that of haemolymph. The osmolarity and the concentration of protein and amino acids in gonadal fluid exceed those of haemolymph. As to the major ions, in the gonadal fluid Na+ is partly replaced by K+, and HCO
3
-
is almost totally replaced by Cl-. Such a distribution of HCO
3
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and Cl- is indicative of metabolic acidosis. The cytochemical localization of carbonic anhydrase activity in cells lining the acinar lumen (Sertoli cells, epithelial cells) suggests that these cells are involved in the process of ion exchange. The metabolic acidosis in the gonad might result from the anaerobic production of lactate and succinate by Sertoli cells; these cells lack the enzymes cytochrome oxidase, lactate dehydrogenase, and succinate dehydrogenase. Spermatogenic cells, on the other hand, do possess these enzymes. This probably indicates that these cells metabolize lactate and succinate secreted by Sertoli cells.The authors are greatly indebted to Prof. Dr. H.H. Boer for stimulating comments during this study, to Dr. C.J.F. van Noorden and Miss Ilse M.C. Vogels for localization of dehydrogenase activity; to Mr. R. van Elk for determining amino acids, and to Dr. W.P.W. van der Knaap for performing the agglutinin assay 相似文献
6.
7.
Two key enzymes of gluconeogenesis, glucose-6-phosphatase and fructosp-1-6-diphosphatase, were present in the cerebral hemispheres,
the cerebellum and the brain stem of the rat brain. Significant activities of these-enzymes were associated with the particulate
fraction. 相似文献
8.
The increased levels of cell adhesion molecules (CAM) have been identified in diabetic vasculatures, but the underlying mechanisms remain unclear. To determine the relationship among vascular production of superoxide, expression of CAM and diabetes, superoxide generation and expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E- and P-selectin in the aorta from control (C57BL/6J) and diabetic mice (ob/ob) were measured. In situ staining for superoxide using dihydroethidium showed an increased superoxide production in diabetic aorta in association with an enhanced NAD(P)H oxidase activity. Immunohistochemical analysis revealed that the endothelial expression of ICAM-1 (3.5 +/- 0.4) and VCAM-1 (3.8 +/- 0.3) in diabetic aorta was significantly higher than that in control aorta (0.9 +/- 0.5 and 1.6 +/- 0.3, respectively). Furthermore, there was a strong positive correlation (r = 0.89, p < 0.01 in ICAM-1 and r = 0.88, p < 0.01 in VCAM-1) between ICAM-1/VCAM-1 expression and vascular production of superoxide. The present data indicate that the increased production of superoxide via NAD(P)H oxidase may explain the enhanced expression of CAM in diabetic vasculatures. 相似文献
9.
Pericytes from Brain Microvessels Strengthen the Barrier Integrity in Primary Cultures of Rat Brain Endothelial Cells 总被引:4,自引:0,他引:4
Nakagawa S Deli MA Nakao S Honda M Hayashi K Nakaoke R Kataoka Y Niwa M 《Cellular and molecular neurobiology》2007,27(6):687-694
(1) The blood–brain barrier (BBB) characteristics of cerebral endothelial cells are induced by organ-specific local signals.
Brain endothelial cells lose their phenotype in cultures without cross-talk with neighboring cells. (2) In contrast to astrocytes,
pericytes, another neighboring cell of endothelial cells in brain capillaries, are rarely used in BBB co-culture systems.
(3) Seven different types of BBB models, mono-culture, double and triple co-cultures, were constructed from primary rat brain
endothelial cells, astrocytes and pericytes on culture inserts. The barrier integrity of the models were compared by measurement
of transendothelial electrical resistance and permeability for the small molecular weight marker fluorescein. (4) We could
confirm that brain endothelial monolayers in mono-culture do not form tight barrier. Pericytes induced higher electrical resistance
and lower permeability for fluorescein than type I astrocytes in co-culture conditions. In triple co-culture models the tightest
barrier was observed when endothelial cells and pericytes were positioned on the two sides of the porous filter membrane of
the inserts and astrocytes at the bottom of the culture dish. (5) For the first time a rat primary culture based syngeneic
triple co-culture BBB model has been constructed using brain pericytes beside brain endothelial cells and astrocytes. This
model, mimicking closely the anatomical position of the cells at the BBB in vivo, was superior to the other BBB models tested.
(6) The influence of pericytes on the BBB properties of brain endothelial cells may be as important as that of astrocytes
and could be exploited in the construction of better BBB models. 相似文献