Biomedical subjects

A Ellinger

Publications and source records attributed to A Ellinger.

At least 37 records · Page 2Linked to original sources

PubMed1998

1,25-Dihydroxy vitamin D3 and tri-iodothyronine stimulate the expression of a protein immunologically related to osteocalcin.

Osteocalcin (OC), a bone-specific protein, is a marker of late osteoblastic differentiation. Its expression is influenced by various growth factors and hormones. We investigated the effect of 1, 25-dihydroxy vitamin D3 (D3) and tri-iodothyronine (T3) on OC expression in osteoblast-like MC3T3-E1 cells. A heterologous OC green fluorescence protein (GFP) fusion vector was established and expressed to study possible effects on protein transport. Immunostaining of endogenous OC revealed a significant increase in the percentage of positive cells after D3 and T3 treatment. This was consistent for MC3T3-E1 cells as well as nonosteogenic NIH-3T3 and mammary carcinoma cells, but not for neuroblastoma cells. The perinuclear immunostaining corresponded to the NBD C6 ceramide Golgi staining. Conversely, we found a strong induction of OC in MC3T3-E1 cells at the mRNA and protein levels only with T3 and not with D3. OC mRNA and protein expression was not detected in NIH fibroblasts. OC GFP transfection experiments indicate rapid transport and secretion of OC, because OC GFP was not found to be accumulated at intracellular compartments after hormone treatment. We conclude that the strong perinuclear immunostaining does not represent OC but a protein immunologically related to OC, as indicated by preabsorption experiments. The expression of this OC epitope-sharing protein is regulated by both D3 and T3 in the osteoblastic MC3T3-E1 and in nonosteogenic cells.

3T3 Cells↗

PubMed1997

Phytopathogenic filamentous (Ashbya, Eremothecium) and dimorphic fungi (Holleya, Nematospora) with needle-shaped ascospores as new members within the Saccharomycetaceae.

Phylogenetic relationships between species from the genera Kluyveromyces and Saccharomyces and representatives of the Metschnikowiaceae (Holleya, Metschnikowia, Nematospora) including the two filamentous phytopathogenic fungi Ashbya gossypii and Eremothecium ashbyii were studied by comparing the monosaccharide pattern of purified cell walls, the ubiquinone system, the presence of dityrosine in ascospore walls, and nucleotide sequences of ribosomal DNA (complete 18S rDNA, ITS1 and ITS2 region). Based on sequence information from both ITS regions, the genera Ashbya, Eremothecium, Holleya and Nematospora are closely related and may be placed in a single genus as suggested by Kurtzman (1995; J Industr. Microbiol. 14, 523-530). In a phylogenetic tree derived from the ITS1 and ITS2 region as well as in a tree derived from the complete 18S rDNA gene, the genus Metschnikowia remains distinct. The molecular evidence from ribosomal sequences suggests that morphology and ornamentation of ascospores as well as mycelium formation and fermentation should not be used as differentiating characters in family delimitation. Our data on cell wall sugars, ubiquinone side chains, dityrosine, and ribosomal DNA sequences support the inclusion of plant pathogenic, predominantly filamentous genera like Ashbya and Eremothecium or dimorphic genera like Holleya and Nematospora with needle-shaped ascospores within the family Saccharomycetaceae. After comparison of sequences from the complete genes of the 18S rDNA the genus Kluyveromyces appears heterogeneous. The type species of the genus, K. polysporus is congeneric with the genus Saccharomyces. The data of Cai et al. (1996; Int. J. Syst. Bacteriol. 46, 542-549) and our own data suggest to conserve the genus Kluyveromyces for a clade containing K. marxianius, K. dobzhanskii, K. wickerhamii and K. aestuarii, which again can be included in the family Saccharomycetaceae. The phylogenetic age of the Metschnikowiaceae and Saccharomycetaceae will be discussed in the light of coevolution.

Microscopy, Electron↗

PubMed1997

Effects of triiodothyronine on the morphology of cells and matrix, the localization of alkaline phosphatase, and the frequency of apoptosis in long-term cultures of MC3T3-E1 cells.

The effects of triiodothyronine (T3) on the localization and morphology of alkaline phosphatase (ALP)-positive cells, matrix formation, and apoptosis in MC3T3-E1 cells cultured up to 6 weeks were investigated by light and electron microscopy. Cell size, shape, and frequency of apoptosis were measured histomorphometrically. At all time points both ALP-positive and -negative cells were observed histochemically. Control cultures older than 3 weeks were characterized by colonies of small cuboidal ALP-positive cells. Cross sections revealed that these areas corresponded to unmineralized nodules. The thickening was caused by local accumulation of extracellular matrix. The internodular regions were characterized by ALP-positive spindle-shaped cells randomly distributed throughout all cell layers. Apoptotic nuclei were found within a frequency of 0.2%-1%. With increasing culture time the percentage of apoptotic cells became higher in the nodules. T3 treatment inhibited cell proliferation and stimulated ALP activity. After confluence, T3-treated cultures reached two to three cell layers at maximum and showed a different morphology and histochemical staining pattern. ALP-positive cells were stellar shaped and larger than unstained cells. Small ALP-positive colonies suggested nodule formation; however, the most striking differences between T3-treated and control cultures were a decrease in the amount of extracellular matrix with only few collagen fibers and the absence of local matrix accumulation. Furthermore, the number of apoptotic nuclei was increased. Our data extend beyond previous observations on the role of thyroid hormones in osteoblastic differentiation. Besides their effects on proliferation and cell morphology, they influence ALP activity, matrix composition, nodule formation, and apoptotic transformation.

Alkaline Phosphatase↗

PubMed1996

The yeast growth control gene GRC5 is highly homologous to the mammalian putative tumor suppressor gene QM.

We isolated the Saccharomyces cerevisiae GRC5 (growth control) gene by functional complementation in vivo of a ts (temperature sensitive) mutation. Phenotypic analysis suggested involvement of GRC5 in cell growth and proliferation. Mutant cells arrest their cell cycles after one to three cell divisions predominantly as mother cells with a large bud. In the region of the septum, a massive accumulation of cell wall material is observed. The mother and daughter nuclei are well separated and spindles are no longer present, while the cytoskeleton is of aberrant appearance. Arrested cells do not perform protein synthesis and are unable to mate. Furthermore, grc5-1ts cells rapidly lose viability at the restrictive temperature (37 degrees C) only on full media, but not under nitrogen-starvation conditions, indicating that proper response to this nutrient limitation is still intact in mutant cells after cell cycle arrest. The sequence of GRC5 translates into a basic protein of 221 amino acid with a corresponding Mr of 25.4 kDa. GRC5 is a member of the highly conserved QM gene family, members of which have been reported from plants, invertebrates and vertebrates. The amino acid sequence of GRC5 over its entire length is more than 60% identical to the human QM protein, expression of which is associated with loss of the tumorigenic phenotype in a cell line derived from Wilms' tumor, a malignancy of the embyronic kidney. Here, we show that GRC5 is an essential yeast gene, the function of which as inferred from analysis of the grc5-1ts mutant is crucial for establishment of proper cytoskeletal structure and regulation of growth in yeast cells.

Base Sequence↗

PubMed1996

Effect of pluronic L-81 on intestinal lipoprotein secretion in the rat.

The hydrophobic nonionic detergent Pluronic L-81 has been shown to lower plasma very-low- and low-density lipoprotein cholesterol, thus preventing diet-induced atherogenesis. The major effect of this agent is a pronounced interference with intestinal lipid metabolism. For studying mesenteric lymph lipoproteins during detergent exposure, a combined micromorphological and biochemical assessment of mucosa and lymph during steady-state lipid absorption was performed. Pluronic L-81 was infused intraduodenally at a constant rate in combination with mixed micellar solutions or saline in mesenteric lymph fistula rats. Pluronic L-81 impairs transepithelial lipid flux during fat absorption, trapping export lipids within the enterocytes and leading to a cytosolic and endoplasmic reticulum lipid accumulation sparing the Golgi region. Pluronic L-81 markedly (P < 0.001) reduces mesenteric triglyceride, phospholipid, and total cholesterol secretion almost exclusively by a reduction of chylomicron formation. Chylomicron and very-low-density lipoprotein lipid composition was only insignificantly altered, except for somewhat higher phospholipid/triglyceride ratios. The chylomicron apoprotein pattern was almost unaffected. Thus, chylomicron formation decreased dramatically without major compositional alterations. The reduction of lipid and apoprotein secretion without particle augmentation is not in favour of a selective interference of Pluronic L-81 with intestinal apoprotein B-48 secretion.

Animals↗

PubMed1996

Active cell death induced by the anti-estrogens tamoxifen and ICI 164 384 in human mammary carcinoma cells (MCF-7) in culture: the role of autophagy.

Active cell death in hormone-dependent cells was studied using cultured human mammary carcinoma cells (MCF-7) treated with the anti-estrogens (AEs) tamoxifen (TAM), 4-hydroxy-tamoxifen (OH-TAM) or ICI 164 384 (10(-8)-10(-5) M) as a model. The following results were obtained. (i) In untreated MCF-7 cells a wave of replication occurred in the first 5 days of culture. All three AEs caused a dose-dependent inhibition of cell replication. (ii) TAM and OH-TAM at 10(-5) M, but not ICI 164 384, caused lytic cell death (necrosis) within 24 h, which was not inhibited by estradiol (10(-9)-10(-6)M). (iii) Lower concentrations of TAM or OH-TAM (up to 10(-6) M) or ICI 164 384 induced a more gradual appearance of cell death beginning at day 3. This type of cell death was inhibited by estradiol (10(-9) M), indicating its active nature. (iv) Nuclei showed two distinct patterns of alteration: (a) apoptosis-like condensation and fragmentation of chromatin to crescent masses abutting the nuclear envelope; (b) condensation of the chromatin to a single, pyknotic mass in the center of the nucleus, detached from the nuclear envelope. Quantitative histological evaluation revealed the predominance of pyknosis. (v) Biochemical DNA analysis revealed that only a relatively small amount of the total DNA was finally degraded into low molecular weight fragments (20 kb and less). (vi) Active cell death, with both apoptotic and pyknotic nuclear morphology, was associated with extensive formation of autophagic vacuoles (AV).3-Methyladenine, a known inhibitor of AV formation, partially prevented cell death as detected by nuclear changes. (vii) ICI 164 384 was about 10 times more effective than TAM or OH-TAM at inhibiting DNA synthesis, but had equal potency in inducing active cell death. It is concluded that AEs have anti-proliferative and anti-survival effects on MCF-7 human mammary cancer cells in culture. These two effects are under separate control because they differ by kinetics, dose dependence and sensitivity to the various AEs. Active cell death in MCF-7 cells seems to be initiated by autophagy, in contrast to concepts of apoptosis, and thus corresponds to autophagic/ lysosomal or type II death as previously defined. This may be important because of biochemical and molecular differences between these various subtypes of active cell death.

Autophagy↗

PubMed1995

Role of active cell death (apoptosis) in multi-stage carcinogenesis.

Active cell death is a genetically encoded self-destruction of a cell. There occur morphologically different types of active cell death, e.g. apoptosis in the liver or autophagic cell death in human mammary carcinoma cells after tamoxifen treatment (Pre)neoplastic lesions in rat liver exhibit enhanced rates of apoptosis, which tend to increase with increasing malignancy. Tumor promoters and non-genotoxic carcinogens inhibit active cell death, thereby increasing the accumulation of (pre)neoplastic cells and accelerating the development of cancer. On the other hand promoter withdrawal, fasting or application of negative growth signals such as transforming growth factor beta 1 (TGF beta 1) enhance apoptosis and can lead to selective regression of preneoplastic lesions or tumors.

Animals↗

PubMed1995

Response of L-929 fibroblasts, human gingival fibroblasts, and human tissue mast cells to various metal cations.

Recent data suggest that under certain conditions, various metal cations are released from dental alloys. These ions may produce adverse effects in various cell types in vivo. In this study, the cytopathogenic effects of 13 metal cations on murine L-929 fibroblasts, human gingival fibroblasts, and human tissue mast cells were analyzed in vitro. Several metal cations (dose range, from 0.0033 to 1.0 mmol/L) were found to induce dose-dependent inhibition of 3H-thymidine incorporation into cultured fibroblasts. The rank order of potency (lowest observed effect level, LOEL) for L-929 fibroblasts was: Ag+ > Pt4+ > Co2+ > In3+ > Ga3+ > Au3+ > Cu2+ > Ni2+ > Zn2+ > Pd2+ > Mo5+ > Sn2+ > Cr2+. A similar rank order of potency was obtained for primary human gingival fibroblasts: Pt4+ > Ag+ > Au3+ > In3+ > Ga3+ > Ni2+ > Co2+ > Zn2+ > Cu2+ > Cr2+ > Pd2+ > Mo5+ > Sn2+. In primary human mast cells, Ag+ and Au3+ caused dose-dependent toxic histamine release, whereas the other metal cations were ineffective over the dose range tested. To investigate the mechanism of metal cation-induced effects, we performed DNA as well as electron microscopic analyses on cultured fibroblasts. Both the DNA pattern and the ultrastructure of L-929 cells and gingival fibroblasts after exposure to cytopathogenic metal cations revealed signs of necrosis but no signs of apoptosis. Together, our data provide evidence that various metal cations produce dose-dependent cytopathogenic effects in distinct cell types, including human gingival fibroblasts and human tissue mast cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

Ultrastructural lectinocytochemistry of fowl plague virus-infected and uninfected MDCK cells.

Using horseradish peroxidase (HRP)-conjugated lectins for pre-embedding labelling we have shown differences in ultrastructural localization of saccharides in cell compartments of fowl plague (FP) virus-infected and uninfected MDCK cells. Lectinochemical staining of the cell compartments in the case of FP virus-infected MDCK cells was less intensive as compared with uninfected cells. Also certain differences in the staining of subcompartments of cell organells were seen. Staining of uninfected cells with Pisum sativum agglutinin (PSA)-HRP revealed an extensive visualization of Golgi complex, mainly its cis-part, TGN vesicles and lysosomes. Staining of FP virus-infected cells with the same lectin marked very lightly rough endoplasmic reticulum and not at all the Golgi complex. Staining with Erythrina cristagalli agglutinin (ECA)-HRP revealed a picture very similar to PSA-HRP staining of uninfected and FP virus-infected cells. The differences in the lectinochemical staining of cell organelles of FP virus-infected and uninfected cells may be connected with the inhibition of cell protein synthesis during FP virus morphogenesis.

Animals↗

PubMed1994

Rat liver endocytic coated vesicles do not exhibit ATP-dependent acidification in vitro.

Coated vesicle fractions from a variety of tissues have been found to contain a vacuolar proton ATPase. Since these fractions contain both plasma membrane- and Golgi-derived coated vesicles, we sought to determine specifically whether endocytic coated vesicles from rat liver contain an active vacuolar proton ATPase. Endocytic vesicles (coated vesicles and endosomes) were selectively labeled with pH-sensitive endocytic tracers (fluorescein isothiocyanate-dextran or -asialoorsomucoid). Coated vesicles were then separated from endosomes by sucrose density gradient centrifugation. Although the endosomal fractions were found to exhibit significant ATP-dependent acidification activity, highly purified coated vesicles containing pH-sensitive endocytic tracers were unable to generate a pH gradient in response to ATP addition. The coated vesicles could be passively acidified, however, by creating potassium diffusion potentials, indicating that they were in fact capable of maintaining proton gradients. Moreover, significant ATP-dependent acidification activity was observed when the coated vesicle fractions were assayed using the nonselective externally added pH probe acridine orange. Thus, it appears that rat liver endocytic coated vesicles do not contain a functional proton pump. The active vacuolar proton ATPase found in these fractions instead reflected the presence of Golgi-derived coated vesicles or contaminating membranes.

Adenosine Triphosphate↗

PubMed1994

Inhibition of P-glycoprotein-mediated vinblastine transport across HCT-8 intestinal carcinoma monolayers by verapamil, cyclosporine A and SDZ PSC 833 in dependence on extracellular pH.

The ability of the multidrug resistance modifiers R- and R,S-verapamil (VPL), cyclosporine A (CsA) and its non-immunosuppressive derivative SDZ PSC 833 (PSC 833) to inhibit P-glycoprotein (P-gp)-mediated transepithelial flux of tritiated vinblastine was investigated using tight and highly resistant (R > 1,400 omega cm2) monolayer cultures of intestinal adenocarcinoma-derived HCT-8 cells grown on permeable tissue-culture inserts. Apical addition of these chemosensitizers inhibited drug flux (137 pmol h-1 cm-2; range, 133-142 pmol h-1 cm-2) in the basal to apical secretory direction at clinically relevant concentrations, with PSC 833 showing the highest activity, exhibiting inhibition at concentrations as low as 10 ng/ml (9 nM). Acidification of the modulator-containing apical compartment to an extracellular pH (pHo) of 6.8 had no influence on MDR reversal by CsA at 1 microgram/ml (0.9 microM; flux inhibition, 52%) or by PSC 833 at 100 ng/ml (0.09 microM; flux inhibition, 60%), in contrast to R,S- and R-VPL, which showed decreased inhibition and caused less accumulation of vinblastine in HCT-8 cells under this condition (flux inhibition of 35% and 23%, respectively, at pHo 6.8 vs 50% and 43%, respectively, at pHo 7.5). P-gp-mediated rhodamine 123 efflux from dye-loaded single-cell suspensions of HCT-8 cells as measured by flow cytometry was not impeded at pHo 6.8 in comparison with pHo 7.5 in standard medium, but at low pHo the inhibitory activity of R-VPL (29% vs 60% rhodamine 123 efflux inhibition) was diminished significantly, again without a reduction in the effect of PSC 833 (rhodamine 123 flux inhibition, 75%). In conclusion, drug extrusion across polarised monolayers, which offer a relevant model for normal epithelia and tumour border areas, is inhibited by the apical presence of R,S- and R-VPL, CsA and PSC 833 at similar concentrations described for single-cell suspensions, resulting in increased (2.2- to 3.7-fold) intracellular drug accumulation. Functional apical P-gp expression, the absence of paracellular leakage and modulator-sensitive rhodamine 123 efflux in single HCT-8 cells indicate a P-gp-mediated transcellular efflux in HCT-8 monolayers. In addition to its high MDR-reversing capacity, the inhibitory activity of PSC 833 is not affected by acidic extracellular conditions, which reduce the VPL-induced drug retention significantly. As far as MDR contributes to the overall cellular drug resistance of solid tumours with hypoxic and acidic microenvironments, PSC 833 holds the greatest promise for clinical reversal of unresponsiveness to the respective group of chemotherapeutics.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1993

Early and late transformations occurring at organelles of the Golgi area under the influence of brefeldin A: an ultrastructural and lectin cytochemical study.

We investigated the early and late changes of the Golgi region under the influence of the fungal metabolite brefeldin A (BFA) by electron microscopy and lectin cytochemistry using the beta-galactose-specific lectin from the beetle Allomyrina dichotoma (Allo A). In control cells, Allo-A reactions were confined to trans-Golgi elements, the trans-Golgi network, and to endosomes and lysosomes; the nuclear envelope and endoplasmic reticulum were consistently free of Allo A reactions. Our findings with cells from three different lines (i.e., HepG2 hepatoma cells, WI38 fibroblasts, and L132 embryonic lung cells) showed tubular-reticular transformations of the Golgi stacks as early as 30 sec after application of BFA. The transformations started at the cis side and proceeded rapidly; after only a few minutes the Golgi apparatus was no longer apparent as an individual entity. Simultaneously, giant tubules grew out of the Golgi region and traversed the cytoplasm over micrometer-long distances. In part, they were reactive for Allo A. Reactions for beta-galactose occurred in cisternae of the endoplasmic reticulum after 4-5 min of BFA treatment; after 30 min the entire endoplasmic reticulum was intensely reactive for Allo A. At 5 min and later, the tubular-reticular transformations appeared more compact, forming glomerulus-like structures (glomerulini). These were closely associated with cisternae of the endoplasmic reticulum. Initially, glomerulini were mostly Allo A negative or showed peripheral Allo A-positive segments. The number of Allo A-positive glomerulini increased with the duration of treatment. Our findings identify the glomerulini as bipolar structures forming a link between the endoplasmic reticulum and the dissociating Golgi stacks.

Brefeldin A↗

PubMed1992

The differential effects of N,N-dimethylformamide and transforming growth factor-beta 1 on a human ovarian cancer cell line (HOC-7).

We have compared the effects of N,N-dimethylformamide (DMF) and transforming growth factor (TGF)-beta 1 on the growth and phenotype of HOC-7 ovarian cancer cells. Previous density gradient fractionation of untreated HOC-7 cells suggested that rapidly growing small polygonal medium density cells revert spontaneously into less malignant flattened low density cells. Here we demonstrate that DMF and TGF-beta 1 induce similar flattened cell phenotypes. Both agents induce qualitatively similar alterations in the cells. DMF, however, exerted stronger effects than TGF-beta 1. The cells become flattened, develop cytoplasmic extensions, and reduce DNA-synthesis as well as anchorage-dependent and -independent growth. These effects are reversible after removal of the inducers, indicating that the cells have not become terminally differentiated. Electron microscopy demonstrates prominent filament bundles in treated cells. Immunofluorescence further shows that these cells contain large amounts of cytokeratin. Immunocytochemistry and ELISA demonstrate 1- to 5-fold higher amounts of desmoplakin and fibronectin after DMF- or TGF-beta 1-exposure. The described differentiation-like responses of HOC-7 cells can be used for recognition of pharmacologically induced maturation of ovarian cancer cells.

Cell Division↗

PubMed1992

DIT101 (CSD2, CAL1), a cell cycle-regulated yeast gene required for synthesis of chitin in cell walls and chitosan in spore walls.

A mutant screen has been designed to isolate mutants in Saccharomyces cerevisiae deficient in spore wall dityrosine. As shown by electron microscopy, most of the mutant spores lacked only the outermost, dityrosine-rich layer of the spore wall. Mutant dit101, however, was additionally lacking the chitosan layer of the spore wall. Chemical measurements showed that this mutant does not synthesize chitosan during sporulation. The mutant spores were viable but sensitive to lytic enzymes (glusulase or zymolyase). Unlike most of the dit-mutants, dit101 did show a distinctive phenotype in vegetative cells: they grew normally but contained very little chitin and were therefore resistant to the toxic chitin-binding dye, Calcofluor White. The cells showed barely detectable staining of the walls with Calcofluor White or primulin. The decrease in the amount of chitin in vegetative cells and the absence of chitosan in spores suggested that the mutant dit101 could be defective in a chitin synthase. Indeed, a genomic yeast clone harboring the gene, CSD2, sharing significant sequence similarity with yeast chitin synthases I and II (C. E. Bulawa (1992), Mol. Cell. Biol. 12, 1764-1776), complemented our mutant and was shown to correspond to the chromosomal locus of dit101. Thus, the mutations dit101 and csd2 (and probably also call; M. H. Valdivieso et al., (1991), J. Cell Biol. 114, 101-109) were shown to be allelic. The gene was mapped to chromosome II and was located about 3 kb distal of GAL1. Using this DNA clone, a transcript of about 3500-4000 nucleotides was detected. Comparing RNA isolated from vegetative cells and from sporulating cells at different times throughout the sporulation process, no significant differences in DIT101 transcript levels could be detected indicating absence of sporulation-specific transcriptional regulation. However, the amount of DIT101 transcript changed significantly at different stages of the mitotic cell cycle, peaking after septum formation, but before cytokinesis. As most of the chitin synthesis of vegetative cells occurs at this stage of the cell division cycle, chitin synthesis mediated by DIT101 could be primarily regulated at the level of transcription in vegetatively growing cells.

Cell Cycle↗

PubMed1992

Subdomains of the rough endoplasmic reticulum in colon goblet cells of the rat: lectin-cytochemical characterization.

Using lectin binding, we characterized subdomains of the rough endoplasmic reticulum (rER) in goblet cells of the rat colon. In this cell type, special rER regions can be differentiated on the basis of their content of low electron density and dilated cisternal spaces in conventional transmission electron microscopic preparations. The fine fibrillar content of these cisternal regions demonstrated high-affinity binding with lectins from wheat germ, Helix pomatia, Griffonia simplicifolia I-A4 and -B4, and Ricinus communis I, although not with the sialic acid-specific Limax flavus lectin and the fucose-binding Ulex europaeus I lectin. Sugar-inhibitory experiments indicated that glycoconjugates packed within these regions bound the lectins with higher affinity than molecules present in the Golgi apparatus and secretory granules. Furthermore, the lectin binding patterns of the rER subdomains differed from those of the Golgi apparatus and mucin granules: the terminal sugar residues sialic acid and fucose were demonstrable in the Golgi apparatus and mucin granules and were absent from the rER, while galactose-recognizing lectins bound intensely at these rER regions, weakly to Golgi elements, and were almost absent from mucin granules.

Animals↗

PubMed1992

[Medical and technical aspects of weapon effects on man. Part 5--Common weapons].

"Weapons at hand" are tools of everyday life, which can be used as instruments for fighting. The investigation offers a survey concerning instruments, which were actually used for conflicting bodily injuries (cases selected from 1029 expertises) or for killing (cases selected from 474 autopsies). The findings are complemented by non-medical publications about self-defence. In the Austrian legal system the use of "weapons at hand" is interpreted like weapons in the technical sense.

Expert Testimony↗

PubMed1991

Cytochemical characteristics of the Golgi apparatus.

Lectinocytochemistry provides a useful tool for localizing subcompartments of the complex reticular apparatus of Golgi. The technique is based on interactions of lectins with glycoconjugates present in the limiting membranes and luminal spaces of Golgi elements. Application of a series of lectins of different sugar specificities permits a differentiation between Golgi subcompartments containing glycoconjugates with different oligosaccharide side chains. These may be a) differnet glycoconjugates or b) glycoconjugates at different stages during synthesis or repair of their glycans. The lectinocytochemical studies with mannose-, glucose-, N-acetyl-glucosamine-, N-acetyl-galactosamine-, galactose-, fucose-, and sialic acid-recognizing lectins revealed predominating patterns that labeled distinct, i.e., cis, medial, trans, and transmost, regions of the Golgi apparatus. A further refinement could be achieved by differential lectin-inhibition that enables a dissection of lectin binding reactions on the basis of their binding affinities. High-affinity binding reactions showed that subcompartments are not necessarily confined to one single Golgi subregion and may change their position from one to another subregion. Some of the patterns observed may be interpreted in relation to certain steps during synthesis and modifications of glycans.

Animals↗

PubMed1991

The effects of dimethyl sulfoxide and retinoic acid on the cell growth and the phenotype of ovarian cancer cells.

We have compared the in vitro effects of the differentiation inducers dimethyl sulfoxide (DMSO) and retinoic acid (RA) on a polyclonal human ovarian cancer cell line (HOC-7). Density gradient fractionation of untreated cells reveals that a proportion of rapidly growing, polygonal cells with medium density is capable of spontaneous reversion into a slowly growing low-density phenotype with flattened morphology similar to non-transformed human ovarian surface epithelial cells. Clonal expansion of these low-density cells proves that the observed characteristics are stable for prolonged culture periods. Exposure of HOC-7 cells to DMSO and RA or removal of the serum from the medium is effective in enhancing the proportion of these low-density cells. Application of DMSO causes the cells to become flattened and elongated, and to develop rod-like protrusions. In these cytoplasmic extensions thick filament bundles are dominant. Immunofluorescence studies demonstrate that both untreated low-density subclones and DMSO-treated polyclonal cells are much more reactive for cytokeratin than medium-density subclones or untreated parental cells. Furthermore, immunocytochemistry and fixed-cell ELISA reveal 2- to 5-fold greater amounts of desmoplakins I and II and of fibronectin in low-density subclones and in DMSO-treated cells as compared to medium-density subclones and control cultures. RA exerts weaker effects on the phenotype of the cells. Both inducers reduce DNA synthesis and inhibit the anchorage-dependent and the anchorage-independent cell growth in a dose- and time-dependent manner. The restoration of the original morphology and growth rate after removal of the differentiation-inducing agents proves that the observed changes are reversible; this indicates that the cells do not become terminally differentiated.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Differentiation↗