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11.
Summary Effects of osmotic conditions on secretion of milk serum were examined using standard transmission electron microscopy. Rat mammary glands were infused with hyper-, iso-, and hypo-osmotic solutions. The intramammary infusion of these agents elicited distinct and repeatable morphological responses from lactating epithelial cells. The response to hyperosmolarity was an increase in compound exocytotic figures and an increase in secretory vesicle size (¯x=1.65 m in diameter). Glands infused with hypo-osmolar solutions exhibited the opposite response; reduction in compound exocytotic figures and reduced vesicle size (¯x=0.34 n in diameter). The response to iso-osmotic solutions was indistinguishable from untreated control tissue. The ratio of vesicular projections to depressions (vesicle membrane/plasma membrane interactions) could be experimentally altered through the intramammary infusion of solutions with different osmotic potentials. These observations support the suggestion that osmotic conditions may influence exocytosis of milk serum. 相似文献
12.
Summary Whether both casein and noncasein (serum or whey) proteins of milk are contained within the same secretory vesicles of milk secreting mammary epithelial cells was explored. Antibodies to a major casein and to -lactalbumin of rat milk were localized in thin sections with colloidal gold-conjugated second antibodies. Antibodies to the casein component bound to an antigen present within lumina of Golgi apparatus cisternae and within secretory vesicles. This antigen was also recognized in structures within secretory vesicles and within alveolar lumina which were ultrastructurally identified as casein micelles. Antigens recognized by antibodies to -lactalbumin also were present in Golgi apparatus cisternae and within secretory vesicles. Both anti-casein and anti--lactalbumin antibodies recognized antigens within the same secretory vesicles. These observations show that one major noncasein protein of rat's milk is present in casein-containing secretory vesicles. 相似文献
13.
Summary The epithelial lining of the mucosa of the edentulous, maxillary alveolar ridge was subjected to an ultrastructural and stereological analysis. Four biopsies collected from the non-inflamed crest, i.e., the center over former tooth sockets, in non-denture-wearing female patients 30 to 55 years of age were processed for light and electron microscopy. At the light-microscopic level, epithelial thickness was determined histometrically. Electron micrographs were sampled at two levels of magnification, from five strata in regions of epithelial ridges and from three strata over connective tissue papillae. Standardized stereological pointcounting techniques were employed to analyze a total of 990 electron micrographs. Observations and data revealed that at the alveolar ridge the oral epithelium is truly keratinizing and comprises four strata including a 40±5 m-thick stratum corneum, which displays the oral keratin pattern. The histoand cytodifferentiation were peculiar: (1) Compared to the neighbouring gingival and hard palate epithelium, that of the alveolar crest was markedly thicker, with elongated rete ridges indicating acanthosis. (2) The cytoarchitecture was identical neither to the gingival nor to the hard palate epithelium but revealed a mixture of features typical for either of these two epithelia. Reasons for this are explained on the basis of factors, possible genetic, inherent in epithelial cells that are possibly derived from both the gingival and the palatal environment. 相似文献
14.
Prof. Dr. med. Wolfgang Schulze Martin Riemer Uwe Rehder Karl-Heinz Höhne 《Cell and tissue research》1986,244(1):1-8
Summary With the use of a digital image-processing method three-dimensional reconstructions of the arrangement of spermatocytes in human seminiferous tubules were performed. With this method it was possible to investigate the cellular distribution in the tubule in nearly any given perspective and projection. In addition, by means of simple mathematical procedures, such as by transformation of Cartesian coordinates into cylindrical coordinates, it was possible to vary the shape of a reconstruction, i.e., to convert the cylindrical image of a tubular portion into a right-angled r--z-representation.The present work not only confirms the existence of a complex helical plan of organization of the human seminiferous epithelium but also provides further aspects of the phenomenon of physiological germ-cell loss and its integration into the kinetics of spermatogenesis.Dedicated to Prof. E.C. Roosen-Runge, Seattle, on the occasion of his 75th birthday 相似文献
15.
Summary An electron microscopic investigation of the extrapulmonary respiratory tract of embryos and chick of the domestic fowl (Gallus domesticus) has demonstrated for the first time in birds the presence here of a small number of epithelial cells characterised by an aminecontaining type of granule. These granular cells were scattered singly throughout the trachea, syrinx and primary bronchi and seemed more numerous in the caudal part of the airway. In favourable planes of section a small part of the cell was in contact with the luminal surface of the epithelium. The characteristic granular vesicles (approximate diameter 140 nm) appeared to be randomly distributed in the cytoplasm and there was no concentration of vesicles close to the plasma membrane. One of the cells was closely associated with an intraepithelial axon. By fluorescence microscopy, a small number of cells with a similar shape and distribution to the granular cells was observed after administration of 3,4-dihydroxyphenylalanine which may indicate the presence of an amine handlign mechanism in these cells. It is suggested that the granular cells belong to the APUD system of endocrine cells and that they may be modulated by the concentration of gas in the airways. 相似文献
16.
17.
R. Joplin A. J. Strain J. M. Neuberger 《In vitro cellular & developmental biology. Plant》1989,25(12):1189-1192
Summary Biliary epithelial cells (BEC) lining the intra-hepatic biliary ducts are the site of damage in several immunologically mediated
liver diseases. BEC are difficult to isolate since they represent only 5% of the total cell number in normal liver. In this
communication, a novel method for their isolation from normal liver is presented using a monoclonal antibody (HEA125) with
specificity for an epithelial cell surface glyco-protein reported to be expressed in liver only by biliary epithelium. By
combining differential density centrifugation and immuno-magnetic separation using HEA125 pure BEC (105 cells/g fresh tissue) were prepared routinely. These cells were maintained in culture for up to 4 weeks with significant
increases in cell numbers. The ability to prepare BEC from human liver offers an opportunity to develop In Vitro models to
investigate the aetiology of diseases in intra-hepatic biliary epithelium.
EDITOR’S STATEMENT This is a novel application to purification of specific liver cell types directly from tissue. It is well-suited
for rapid communication because of its novelty and potential utility to investigators. 相似文献
18.
James C. Beck Howard L. Hosick Bruce A. Watkins 《In vitro cellular & developmental biology. Plant》1989,25(5):409-418
Summary We investigated the effects of conditioned media derived from mouse mammary fat pads on the proliferation of CL-S1 cells,
an epithelial cell line originally isolated from a preneoplastic mammary outgrowth line. Cell proliferation in vitro in serum-free
defined medium was compared to that in this medium conditioned using intact mammary fat pad pieces or isolated fat pad adipocytes.
Culture medium was conditioned by incubating the conditioning material in defined culture medium for 24 h at 37°C. Conditioned
medium induced CL-S1 proliferation as much as 10- to 20-fold above the minimal levels of growth in control cultures after
13 d of culture. The growth-stimulatory factor(s) had an apparent molecular weight of greater than 10 kDa. This growth-stimulatory
activity was both heat and trypsin stable. Because the role of adipose tissue is to store and release lipids, we next tested
whether lipids are released during medium conditioning. The lipid composition of the fat pad conditioned medium was characterized
using both thin layer and gas liquid chromatography. These lipid analyses indicated that the fat pad pieces released significant
amounts of fatty acids and phospholipids into the medium during the conditioning period. The free fatty acid composition included
both saturated and unsaturated molecules, and about 80% of the total fatty acids consisted of palmitate, stearate, oleate,
and linoleate. These same fatty acids were a structural component of the majority of phospholipid found in the medium. The
addition of palmitate or stearate to defined medium had no effect or was inhibitory for CL-S1 proliferation, depending on
the concentration used. Defined medium supplemented with oleate, arachidonate, or linoleate induced CL-S1 proliferation, and
the inhibitory effects of palmitate and stearate were overcome by addition of oleate and linoleate. These data indicate that
both unsaturated and saturated fatty acids are released from intact adipose cells of the mouse mammary fat pad and that fatty
acids can influence the growth of prenoplastic mouse mammary epithelium. Thus, unsaturated fatty acids, perhaps in conjunction
with other substances released simultaneously, are candidate molecules for the substances that mediate the effect of adipose
tissue on growth of epithelium.
This work was supported in part by a grant from the American Institute for Cancer Research; grant CA 46885 from the National
Institutes of Health, Bethesda, MD; and by State of Washington initiative 171. 相似文献
19.
Summary Interactions between epithelial cells and their environment are critical for normal function. Mammary epithelial cells require hormonal and extracellular matrix (ECM) signalling for the expression of tissue specific characteristics. With regard to ECM, cultured mammary epithelial cells synthesize and secrete milk proteins on stromal collagen I matrices. The onset of function coincides both with morphogenesis of a polarized epithelium and with deposition of basement membrane ECM basal to the cell layer. Mammary specific morphogenesis and biochemical differentiation is induced if mammary cells are cultured directly on exogenous basement membrane (EHS). Thus ECM may effect function by the concerted effect of permissivity for cell shape changes and the direct biochemical signalling of basement membrane molecules.A model is discussed where initial ECM control of mammary epithelial cell function originates in the interstitial matrix of stroma and subsequently transfers to the basement membrane when the epithelial cells have accumulated and deposited an organized basement membrane matrix.Dedicated to Professor Stuart Patton on the occasion of his 70th birthday. 相似文献
20.
We have tested the ability of several B2 antagonists on the responses of the open-circuited isolated canine tracheal epithelium to the luminal addition of Bradykinin (BK), Lys-BK, and substance P (SP). All three peptides produced biphasic changes in transmural potential difference (PD), an initial decrease (dip) followed by an increase (rise). The B2 antagonists
-Argo [Hyp3,Thi5,8,
-Phe7]BK (B5630) reversibly inhibited both the dips and the rise with IC50 values of 2.01 · 10−8 and 1.54 · 10−7 M, respectively. The responses to SP were unaffected even with high concentrations of the antagonist. Other antagonists tested [
-Phe1,7,Thi5,8]BK (B4158), [
-Phe2,7]BK (B4404), and [
-Phe7,Hyp8]BK (B5092) were ineffective. 相似文献