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241.
B. Sporrong P. Kannisto Prof. Ch. Owman N. -O. Sjöberg B. Walles 《Cell and tissue research》1985,241(3):505-511
Summary With the use of an anti-human S-100 protein antibody, it was possible to reveal a characteristic cell type in the anterior lobe of the normal human pituitary. These cells, so-called folliculo-stellate cells, were present in all pituitaries studied but their number varied from one gland to another. Immunoreactive cells, isolated or grouped, were arranged close to various secretory granulated cells. Especially by use of double immunoenzymatic labeling, it was evident that these cells are spatially related either to somatotropes, prolactin cells and corticotropes, or to glycoprotein-containing cells. Such immunoreactive cells were rare or absent in pseudo-follicular arrangements of secretory granulated cells. Since it is now possible to identify this cell type by light microscopy and since no reliable functional significance is known, it seems more advisable to term this cell type stellate cell instead of folliculostellate cell. 相似文献
242.
Simon C. Nemtzov 《Environmental Biology of Fishes》1985,14(2-3):199-211
Synopsis The Red Sea razorfish, Xyrichtys pentadactylus, a territorial haremic labrid with dominance hierarchies within the harems. Theory predicts that primary males (fish developing initially as males) should be rare or nonexistent in haremic territorial species because the larger secondary males (males which have undergone sex and/or color change) limit access to females. Histological examination of gonads of 95 specimens showed that all males are derived from females by sex change (i.e. they are secondary males). During five months of field studies 100% of more than 200 observed matings were pair spawnings — the usual mating practice for monandric (having one type of male) species. Sex change in females was induced by male removal in nature. Isolation of four groups of females in aquaria showed that the largest female in the social group changes sex in the absence of a male, demonstrating that sex change is socially-controlled in this species. 相似文献
243.
Summary Human umbilical vein endothelial cells (HUV-EC) grew rapidly in vitro in medium supplemented with epidermal growth factor,
fetal bovine serum (FBS) and human diploid fibroblast-conditioned medium. The effect of FBS could be replaced partially by
bovine serum albumin, cholesterol, and vitamin E, and completely by further addition of serum dialysate or refeeding every
other day. Among these components, fibroblast-conditioned medium is essential for HUV-EC growth. The HUV-EC were cultured
serially for over 50 population doublings in the 10% FBS containing fibroblast-conditioned medium and for over 40 population
doublings in the serum-free medium. Mitogenic factor(s) present in the medium conditioned by fibroblasts may be related to
endothelial cell growth factor and play an important role angiogenesis and regeneration of vascular endothelium in vitro. 相似文献
244.
Steinar Solberg Tor Larsen Leif Jørgensen 《In vitro cellular & developmental biology. Plant》1985,21(11):612-616
Summary This study examined whether nonconfluent endothelial cell cultures reacted differently than confluent ones toward thrombin-stimulated
platelets or a heparinized salt solution. The adherence to the endothelial cell cultures of51Cr-labeled human platelets stimulated at different thrombin concentrations was studied. There was significantly higher adherence
of stimulated platelets to nonconfluent cultures compared with confluent ones. This was confirmed by scanning electron microscopy,
which also revealed a tendency for the platelets to adhere at the cell periphery. Electron microscopy also showed that thrombin-stimulated
platelets induced endothelial cell contraction. Part of the peripheral endothelial cell surface toward the bottom of the culture
dish was inverted, facing the lumen of the dish. This phenomenon was particularly seen in nonconfluent cultures. When51Cr-labeled endothelial cultures were incubated with a mildly injurious fluid as heparinized sodium acetate and 20% serum,
at 20° C for 30 min, the nonconfluent cultures showed significantly more cell detachment and release of51Cr than the confluent ones. We conclude that under the conditions of the present experiments there are differences in the
reactivity of confluent and nonconfluent endothelial cell cultures. These differences probably reflect biological dissimilarities.
In experiments where properties of cultured endothelium are studied, care should be taken that the degree of confluency is
standardized. 相似文献
245.
Degradation of extracellular matrix by the trophoblastic cells of first-trimester human placentas 总被引:6,自引:0,他引:6
S J Fisher M S Leitch M S Kantor C B Basbaum R H Kramer 《Journal of cellular biochemistry》1985,27(1):31-41
First-trimester human placental villi were cultured on 3H-leucine-labeled extracellular matrices isolated from the PF HR9 and PYS-2 cell lines. Both cell lines produced an extracellular matrix that contained basement membrane-specific macromolecules, including type IV collagen, laminin and proteoglycan. Both matrices promoted outgrowth of cells from the villi which, according to morphological criteria, were identified as cytotrophoblastic cells. As the cells migrated from the attachment site, they caused a marked focal dissolution of the matrix which was accompanied by a concomitant release of 3H-labeled material into the media. Approximately half of this material chromatographed near the inclusion volume of Sephadex G-50, indicating that the labeled matrix components had been degraded. This phenomenon was dependent on the age of the placenta. Second-trimester placental villi also adhered to the matrix, but no areas of dissolution were formed and no significant amounts of radioactivity were released into the medium. These results suggest that culture of first-trimester human placental villi on extracellular matrices may be useful for the study of some of the early embryonic events leading to human implantation, during which the trophoblastic cells erode the uterine epithelium. 相似文献
246.
247.
Effects of fructose on human fibroblast metabolism: the application of DNA measurements as a basis for interpretation 总被引:2,自引:0,他引:2
Robert Z. Eanes 《In vitro cellular & developmental biology. Plant》1985,21(6):328-332
Summary A fluorometric procedure for measuring DNA was used to study growth and metabolic responses of eight cell strains of human
foreskin fibroblasts. In preliminary studies this procedure gave more precise specific activity changes inN-acetyl-β-d-glucosaminidase (NAG) than did a protein activity basis, when changes in this enzyme's specific activity were investigated
as a function of experimental cell manipulation. When fibroblast growth in eight cell strains was compared in 134 mM
d-fructose vs. 13.4 mM glucose-supplemented minimum essential media, a significant increase in cellular DNA (50%) and protein (45%) occurred over
an 11-d period. No significant differences in media pH change, lactate production, or carbohydrate uptake occurred on a DNA
basis when cell metabolism was compared over the last 24 h of culture in the two media. Cells grown in fructose-containing
media tended to show a reduction in NAG specific activity when compared with those grown in glucose-containing media. 相似文献
248.
John E. Gould James W. Overstreet Frederick W. Hanson 《Molecular reproduction and development》1985,12(1):47-54
The functional capacity for sperm interaction with the human zona pellucida and zona-free hamster oocyte was tested after human spermatozoa were capacitated by passage through a column of human cervical mucus. The results were compared with those obtained when spermatozoa from an aliquot of the same semen sample were capacitated by the standard laboratory methods involving sequential washing by dilution and centrifugation of the semen. Washed-capacitated sperm suspensions were more successful than mucus-capacitated sperm in attaching to the zona-free hamster oocyte and in fusing with its oolemma. However, the ability of mucus-capacitated sperm to penetrate the human zona pellucida was equal to washed capacitated sperm. These experiments demonstrate an approach that may be useful in comparative studies of human sperm capacitation in vivo and in vitro. 相似文献
249.
Age-dependent metabolic changes in cultured human fibroblasts 总被引:1,自引:0,他引:1
A. L. Muggleton-Harris R. Defuria 《In vitro cellular & developmental biology. Plant》1985,21(5):271-276
Summary The effects of metabolic poisons on the ATP content of cultured human skin fibroblasts at selected in vitro and in vivo ages
were studied. Potassium cyanide, iodacetemide, and Arsenate were used to inhibit ATP restoration by glycolysis and oxidative
phosphorylation. Cells treated with these metabolic poisons showed an age-dependent change in their ATP content. The decrease
in cellular ATP content after exposure to these drugs was taken as an estimate of ATP turnover. It was found that there was
a decrease in the ATP turnover with increasing population doubling level (i.e. in vitro age), and cells cultured from a 68-yr-old
donor had a lower ATP turnover than those cultured from a neonatal donor. This decreased ATP turnover correlates with a previous
finding of a decreased ability of “older” cells to be stimulated to migrate in culture and suggests that there is a metabolic
component to this age-related functional deficiency.
This work was supported by National Institutes of Health grants 2, RO1 EY02523 and 1 RO1 1, AGO 1212 awarded to A.L. Muggleton-Harris. 相似文献
250.
Phytoplankton ecology in an unusually stable environment (Montezuma Well,Arizona, U.S.A.) 总被引:1,自引:0,他引:1
Relatively minor annual amplitudes of change in certain major nutrients, and especially pH and water temperature were measured in the spring-fed system of Montezuma Well, Arizona during a four year study. phytoplankton diversity was low but for the most part, composition was spatially and temporally constant; total seasonal phytoplankton density was significantly correlated with regional incident light. Phytoplankton species composition changed briefly during and for a short period following the summer monsoon. Ultraplankton (<5 µm diam.) numerically comprised nearly 80% of the phytoplankton community throughout most of the year. The limited residence time of water in the Well may have provided a competitive advantage for cells with high surface area:volume ratios and correspondingly rapid division rates. Nannochloris bacillaris Naum. and Coccomyxa minor Skuja were perennial dominants. Diatom populations did not increase with annual increases in vernal solar radiation. Low pH, high dissolved CO2, and limited residence time for metabolic inhibitors are considered to be largely responsible for the reduced blue-green populations in the Well. The only flagellated photosynthetic group present in Montezuma Well was the Cryptophyta. Desmid populations were minimal, even though pH was consistently below circumneutral (6.5) and free CO2 concentrations high. The role of grazing by an amphipod, Hyalella montezuma, on annual phytoplankton abundance is examined. 相似文献