共查询到10条相似文献,搜索用时 171 毫秒
1.
Hans-Peter Baum J?rg Reichrath Andrea Theobald Gudrun Schock 《The Histochemical journal》1994,26(12):929-933
Summary In contrast to that in paraffin-embedded tissue, the reactivity of monoclonal PCNA antibody PC10 on cryostat sections requires
a special fixation procedure as the target epitope is seemingly not accessible to its antibody. A panel of 18 fixation protocols
was investigated. Chilled methanol or acetone, or PLP (paraformaldehyde-lysine-periodate) was found to be unsuitable for skin
preparations. A two-step fixation protocol was developed for normal skin and basal cell carcinomas. They were fixed first
in 3.4% buffered formaldehyde, followed by fixation in 2:1 v/v ethanol-acetic acid. Following this fixation regime, cryostat
sections displayed the same PCNA/PC10 labelling pattern as paraffin sections of formalin-fixed tissue. 相似文献
2.
Janice Yang Chou Patricia E. Hugunin Toshiaki Mano 《In vitro cellular & developmental biology. Plant》1983,19(7):571-575
Summary The synthesis of human chorionic gonadotropin (HCG), the subunit of HCG (HCGα), and pregnancy-specific β1-glycoprotein (PSβG) was studied in temperature senstive (ts), simian virus 40 (SV40)tsA mutant-transformed human first trimenster placental (SPA255-26) cells. Retinoic acid increased the production of HCG and PSβG but inhibited the production of HCGα in these cells. Passage
ofSPA255-26 placental cells in medium containing retinoic acid induced a stable altered phenotype characterized by elevated levels of
HCG and PSβG and a reduced level of HCGα. The retinoic acid induced phenotypic changes in these placental cells were reversible;
removal of retinoic acid immediately decreased the production of HCG and PSβG while increasing the production of HCGα. The
ratio of HCG to HCGα in controlSPA255-26 cells was approximately 0.1; this ratio in creased to 4.8 in cells maintained in medium containing retinoic acid. Similarly,
the HCG-to-HCGα ratio increased in choriocarcinoma cells maintained in retinoic acid containing medium. Our data suggest that
retinoic acid may be needed to maintain a blanced production of HCG, HCGα, and PSβG in placental cells in vitro. Retinoic
acid may also play a role in modulating placental protein production during pregnancy. 相似文献
3.
Up-regulation of E-cadherin and β-catenin in human hepatocellular carcinoma cell lines by sodium butyrate and interferon-α 总被引:1,自引:0,他引:1
Masuda T Saito H Kaneko F Atsukawa K Morita M Inagaki H Kumagai N Tsuchimoto K Ishii AH 《In vitro cellular & developmental biology. Animal》2000,36(6):387-394
Summary Human E-cadherin is a homophilic cell adhesion molecule and its expression is well preserved in normal human hepatocytes;
a decrease in its expression has been observed in poorly differentiated hepatocellular carcinoma cells. We examined the alteration
of E-cadherin and catenin expressions caused by differentiation inducers in human hepatocellular carcinoma cells. Hepatocellular
carcinoma cell lines, HCC-T and HCC-M, were cultured with all-trans retinoic acid (ATRA), dexamethasone (DEX), sodium butyrate, and interferon-α. E-cadherin expression was only up-regulated
by butyrate and interferon-α (IFN-α) in both cell lines, studied by means of fluorescence immunostaining and flow cytometry.
The localization of E-cadherin staining was shown at their cell membrane. According to the increase in E-cadherin expression,
β-catenin expression appeared at the cell membrane of both cell lines when treated with butyrate and IFN-α. Such an appearance
was not observed when cells were treated with ATRA and DEX. Western blotting showed that α-and γ-catenin expression was not
changed, while only the expression of β-catenin increased. β-Catenin oncogenic activation as a result of amino acid substitutions
or interstitial deletions within or including parts of exon 3, which has been demonstrated recently, was not detected in these
cell lines by direct deoxyribonucleic acid sequencing. These results suggest that the expression and interaction between E-cadherin
and wild-type β-catenin are potentially modulated by butyrate and IFN-α, and that these two agents are potent inhibitors of
hepatocellular carcinoma cell invasion and metastasis. 相似文献
4.
Lone Rønnov-Jessen Bo van Deurs Maja Nielsen Ole W. Petersen 《In vitro cellular & developmental biology. Animal》1992,28(4):273-283
Summary Myofibroblasts from human breast carcinomas were identified and experimentally generated in culture, and a possible function
was examined. The frequency ofα-smooth muscle actin immunoreactive cells was evaluated as a measure of myofibroblast differentiation in primary culture.
Few or noα-smooth muscle actin-positive stromal cells (6.1 ± 8.4%) were identified in primary cultures from normal breast tissue (n=9). In contrast, high frequencies (68.8 ± 15.1%) were observed in primary cultures from carcinomas (n=19). The frequencies of myofibroblasts in primary cultures were almost identical to those obtained in the corresponding cryostat
sections (69.1 vs. 68.8%). A possible precursor cell to the myofibroblast was looked for among typical fibroblasts and vascular
smooth muscle cells. Purified blood vessels containing both fibroblasts and vascular smooth muscle cells were embedded in
collagen gel and incubated with medium conditioned by breast epithelial cells. Fibroblasts rather than smooth muscle cells
were recruited from the blood vessels. In medium conditioned by carcinoma cell lines or in co-cultures of carcinoma cell lines
and purified fibroblasts,α-smooth muscle actin and the typical myofibroblast phenotype were induced in otherwiseα-smooth muscle actin-negative fibroblasts. The effect of myofibroblasts on cellular movement—essential to neoplastic cells—was
analyzed. Spontaneous motility of tumor cells (MCF-7) was entirely suppressed in a collagen gel assay. Under these conditions
tumor cell motility was selectively mediated by direct cell-to-cell interaction between tumor cells and myofibroblasts. Under
chemically defined conditions, interaction was dependent on the presence of plasminogen. Anti-plasminogen, soybean trypsin
inhibitor, and anti-fibronectin partly neutralized the effect of plasminogen. It is concluded that elements of myofibroblast
differentiation and function may be studied in culture. 相似文献
5.
Thomsen-Friedenreich-related carbohydrate antigens in normal adult human tissues: a systematic and comparative study 总被引:5,自引:2,他引:3
Yi Cao Peter Stosiek Georg F. Springer Uwe Karsten 《Histochemistry and cell biology》1996,106(2):197-207
A broad variety of normal human tissues were examined for the expression of Thomsen-Friedenreich (TF)-related histo-blood
group antigens. TF (Galβ1-3GalNAcα1-R), Tn (TF precursor, GalNAcα1-R), sialosyl-Tn (NeuAcα2-6GalNAcα1-R), considered to be useful in cancer diagnosis and immunotherapy, and sialosyl-TF, the cryptic form of TF. These antigens
or, more correctly, glycotopcs, were determined by immunohistochemistry with at least two monoclonal antibodies (mAbs) each
(except sialosyl-TF) as well as by lectin histochemistry. For a better dissection of sialosyl-TF and TF glycotopes, tissue
sections were pretreated with galactose oxidase or the galactose oxidase-Schiff sequence. Staining with mAbs appeared to be
more restricted than with the lectins used. Distribution patterns among normal epithelia were different for all four antigens.
These antigens were also detected in some non-epithelial tissues. They can be classified in the following sequence according
to the frequency of their occurrence in normal tissues: sialosyl-TF> >sialosyl-Tn>Tn>TF. Most of the positively staining sites
for TF, Tn, and sialosyl-Tn are located in immunologically privileged areas. The complex results obtained with anti-TF mAbs
(after treatment of the tissue sections with sialidase fromVibrio cholerae) and the lectins amaranthin and jacalin revealed a differential distribution of the subtypes of sialosyl-TF [NeuAcα2-3Galβ1-3GalNAcα1-R and Galβ1-3 (NeuAcα2-6)GalNAcα1-R] in normal human tissues. From our data it can be inferred that TF, Tn, and sialosyl-Tn are promising targets for a
cancer vaccine. 相似文献
6.
Human skin may be considered as a target organ for androgens, as are male sex accessory organs, since all events involved
in testosterone action have been observed in this tissue. As a corollary, the mechanism of androgen action can be studiedin vitro in cultured skin fibroblasts. The advantages of this system are that studies can be performed with intact human cells under
carefully controlled conditions, differentiated genetic and biochemical characteristics of the cells are faithfully preserved
and the biological material is renewable from a single biopsy specimen. The metabolism of androgens, in particular the 5α-reduction
of testosterone to the active metabolite, dihydrotestosterone, the intracellular binding of androgen to its specific receptor
protein and its subsequent translocation to the nucleus have been studied in skin fibroblasts. The intracellular androgen
receptor content of genital skin fibroblasts is higher than that from nongenital skin sites. In addition, the androgen receptor
has been characterized as a specific macromolecule with properties of high affinity and low capacity similar to that of other
steroid hormone receptors.
The pathophysiology of three genetic mutations which alter normal male sexual development and differentiation has been identified
in the human skin fibroblast system. In 5α-reductase deficiency, an autosomal recessive disorder in which dihydrotestosterone
formation is impaired, virilization of the Wolffian ducts is normal but the external genitalia and urogenital sinus derivatives
are female in character. At least two types of X-linked disorders of the androgen receptor exist such that the actions of
both testosterone and dihydrotestosterone are impaired and developmental abnormalities may involve both Wolffian derivatives
and the external genitalia as well. These two forms of androgen insensitivity result from either the absence of androgen receptor
binding activity (receptor(−)form) or apparently normal androgen receptor binding with absence of an appropriate biological
response (receptor (+) form). In addition, studies with human skin fibroblasts may also be of value in defining the cellular
mechanisms underlying the broad spectrum of partial defects in virilization.
In summary, we have correlated our studies of the molecular mechanism of androgen action in human genital skin fibroblasts
with those of other investigators as these studies contribute to our understanding of male sexual development and differentiation. 相似文献
7.
Summary Traditional protocols for the immunohistochemical localization of peptides and tyrosine hydroxylase (TH) in nerve fibers in cryostat sections require the tissue to be thoroughly fixed and rinsed and to be processed for the cryostat sectioning and the immunohistochemical staining more or less directly after freezing. In the present study it was tested whether also unfixed, rapidly frozen tissue, conforming to guinea pig and bovine heart specimens, can be used for the visualization of neuropeptides [neuropeptide Y (NPY) and substance P (S P)] and TH in cryostat sections. The following observations were made: 1) NPY-immunoreactive (IR) and S P-IR nerve fibers could be clearly identified in both fixed and unfixed sections of this type of tissue. 2) TH-IR nerve fibers could be detected in unfixed tissue if the sections were post-fixed with aldehydes by the use of a two-step fixation process related to a sudden change of pH. However, the outlines of the nerve fibers were sometimes diffuse. 3) Storage of unfixed tissue for periods of up to 2.5 yeart at –80° C did not lead to a decrease in immunoreactivity. 4) Somewhat higher concentrations of primary antibodies had to be used for sections of unfixed tissue than for sections of fixed tissue when the FITC method was used. This waste of antibodies was partly overcome by use of the biotin-streptavidin method. The glyoxylic acid induced catecholamine(CA)-fluorescence method for demonstration of sympathetic nerve fibers was also applied and was found to give optimal results after storage of tissue for up to 2.5 years. The study shows that the use of unfixed rapidly frozen tissue represents a fast and realistic method for the demonstration of neuropeptide immunoreactivity, that it to some extent can be used for the visualization of TH-containing nerve fibers and that it is a suitable method to maintain longterm neuropeptide and TH immunoreactivity as well as long-term CA-fluorescence reaction. 相似文献
8.
Sequence analysis and receptor specificity of the hemagglutinin of a recent influenza H2N2 virus isolated from chicken in North America 总被引:2,自引:0,他引:2
Glaser L Zamarin D Acland HM Spackman E Palese P García-Sastre A Tewari D 《Glycoconjugate journal》2006,23(1-2):93-99
Influenza viruses bind host cells following an interaction between the viral hemagglutinin (HA) protein and host cell sialylated
glycoproteins and glycolipids. Differences in binding affinities of the HAs for different types of sialic acid linkages (α2-3 vs. α2-6) contribute to determining the host range of an influenza virus. The ability of an avian influenza virus HA to bind the
human form of the receptor may be one requirement for an avian virus to propagate in the human population. In this paper,
we describe the characterization of the HA from an H2N2 virus isolated from a Pennsylvania chicken farm in 2004. Sequence
analysis revealed that this HA is a member of the Eurasian clade, and receptor binding studies show that it maintains its
specificity for the avian influenza virus α2-3 linked sialic acid receptor. 相似文献
9.
Christel Metzger Svetlana Radaeva Doris Mayer Alessia D’Introno P. Bannasch 《Histochemistry and cell biology》1998,110(3):323-332
Ultrastructural studies of rare and small cellular lesions in pathologically altered tissue are difficult to perform by applying
conventional electron microscopic preparation. The search for lesions, often consisting of only a few cells in randomly obtained
small specimen blocks, is time consuming and often without success. The methodological requirements for comparative enzyme
cytochemical and morphological studies, i.e., preservation of both enzyme activity and ultrastructure, are divergent. By processing
large native cryostat sections for electron microscopy, small preneoplastic focal lesions were successfully targeted in liver
and kidney. Glucose-6-phosphatase, alkaline phosphatase, acid phosphatase, catalase, and cytochrome c oxidase activities were distinctly localized to endoplasmic reticulum, canalicular membrane, lysosomes, peroxisomes, and
mitochondria, respectively, in the morphologically altered cells. Fixation of serial cryostat sections and enzyme reactions
were both carried out through a semipermeable membrane except those for cytochrome c oxidase, which was demonstrated after fixation through the membrane by floating the section in incubation medium containing
cytochrome c. Thereafter, the sections were flat embedded and polymerized between epoxy resin disks and aluminum dishes fitting exactly
together. The objects of interest were identified in the light microscope, cut out, and reembedded in reversed gelatine capsules.
By using this technique an ultrastructural preservation was achieved similar to that seen after immersion fixation. The enzyme
activities were clearly localized without diffusion of the reaction product or unspecific deposits. The procedure permits
precise targeting and complex studies of rare and small lesions, and opens new perspectives for the use of cryo-preserved
tissue.
Accepted: 10 March 1998 相似文献
10.
Karthik Viswanathan Aarthi Chandrasekaran Aravind Srinivasan Rahul Raman V. Sasisekharan Ram Sasisekharan 《Glycoconjugate journal》2010,27(6):561-570
Influenza A viruses, members of the Orthomyxoviridae family, are responsible for annual seasonal influenza epidemics and occasional global pandemics. The binding of viral coat
glycoprotein hemagglutinin (HA) to sialylated glycan receptors on host epithelial cells is the critical initial step in the
infection and transmission of these viruses. Scientists believe that a switch in the binding specificity of HA from Neu5Acα2-3Gal
linked (α2-3) to Neu5Acα2-6Gal linked (α2-6) glycans is essential for the crossover of the viruses from avian to human hosts.
However, studies have shown that the classification of glycan binding preference of HA based on sialic acid linkage alone
is insufficient to establish a correlation between receptor specificity of HA and the efficient transmission of influenza
A viruses. A recent study reported extensive diversity in the structure and composition of α2-6 glycans (which goes beyond
the sialic acid linkage) in human upper respiratory epithelia and identified different glycan structural topologies. Biochemical
examination of the multivalent HA binding to these diverse sialylated glycan structures also demonstrated that high affinity
binding of HA to α2-6 glycans with a characteristic umbrella-like structural topology is critical for efficient human adaptation and human-human transmission of influenza A viruses. This
review summarizes studies which suggest a new paradigm for understanding the role of the structure of sialylated glycan receptors
in influenza virus pathogenesis. 相似文献