bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in annexin (lipocortin) content in human amnion and chorion at parturition
Authors: Myatt L. , Hirth J. , Everson W. V. 
Published: May 2005

AbstractArachidonic acid is mobilized from fetal membrane phospholipids at paturition leading to increased production of oxytocic prostaglandins which may initiate or maintain myometiral contractions. Phospholipid mobilization requires activation of phospholipase A2 or C both of which require calcium for activity. The annexins (lipocortins) are a superfamily of proteins which bind to calcium and phospholipids thereby may alter phospholipase activity through two mechanism: modulation of intracellular free Ca2+ concentration or regulation of the accessibility of phospholipids to hydrolyzing enzymes. Using Western immunoblotting with monospecific polyclonal antibodies, annexins I–VI were identfied in human amnion and chorion/decidua at term in tissues obtained from patients in labor or not in labor. Each annexin was present in two distinct pool: a pool which only associated with the membrane in the presence of calcium (calcium‐dependent pool) and a calcium‐independent pool that remained membrane bound in the presence of calicium chelators. Annexin I was present as two species, resolving at 36 kDa and 68 kDa. The total concentration of annexin I in both amnion and chorion/decidua was significantly decreased with labor, while the total concentration of annexin V in chorion significantly increased with labor. The size of individual pools of annexins also changed with labor: the calcium‐dependent pool of annexins I and II in both amnion and chorion significantly decreased; the calcium‐dependent pool of annexin V increased in chorion; and calcium‐independent pools of annexin I in amnion and annexins I, II, and V in chorion significantly decreased with labor. The decrease in totoal annexin I concentration with labor in amnion reflects a substantial decrease (80–90%) in the pool tightly bound to the membrane in a calcium‐independent manner. The striking change distinguishes annexin I as a potential candiate inhibitor which is specially downgregulated a parturition, potentially leading to increased access of phospholipases to substrate phospholipids and increased prostglandins production at labor. © 1992 Wiley‐Liss, Inc.
Acidic fibroblast growth factor modulates gene expression in the rat thyroid in vivo
Authors: Chanoine Jean‐Pierre , Braverman Lewis E. , DeVito William J. , Stein Gary S. , Shalhoub Victoria , Lian Jane B. , Huber Chris A. 
Published: May 2005

AbstractWe have recently demonstrated that the iv administration of acidic fibroblast growth factor(a‐FGF) to rats for 6 days results in a marked increase in thyroid weight colloid accumulation and flat, quiescent follicular cells. Whereas a‐FGF administration consistently increases thyroid weight, there are only minor alterations in serum TSH and thyroid hormones, and no change in intrathyroidal metabolism of 125l metabolism. In the present work, we studied the effects of 1 or 6 daily injections of a‐FGF (60 μ/kg BW) or vehicle on the mRNA levels for histone, c‐fos, actin, type I 5′ deiodinase (5′D‐1), thyroid peroxidase, and thyroglobulin and cathepsin D in the thyroid, liver and bone. Rats were sacrificed 0.5, 2, 4, 8 and 24 h after the 1st or the 6th a‐FGF injection and thyroid, liver and calvarium were removed. The relative amounts of mRNAs were determined by slot blot analysis. There was a 43% increase in thyroid weight in rats treated with a‐FGF for 6 days compared to vehicle‐treated rats. We observed an increase in c‐fos mRNA content in the thyroid gland 0.5 to 4 h after 1 or 6 injections of a‐FGF. In contrast, treatment with a‐FGF for 1 or 6 days did not affect histone mRNA content, a marker of proliferative activity or actin mRNA levels. Treatment with a‐FGF caused a marked decrease in thyorid 5′ D‐I mRNA content in the thyroid. The decrease was present 2 h after the first injection and reached a nadir 8 h. After 6 daily injections, the decrease in 5′ D‐I mRNA was present throughout the whole day. In the liver, there was a significant decrease in 5′ D‐1 mRNA only 2 and 4 h after the 6daily injection of a‐FGF. There was no effect of a‐FGF treatment on the mRNA content of thyorid peroxidase, thyroglobulin, or a marker of lysosomal activity, cathepsin D. These data indicate that a‐FGF induces colloid accumulation in the rat thyroid without changes in proliferative or lysosomal activites, or alteration in the regulation of the thyroid specific genes thyroid peroxidase and thyroglobulin. Modification in gene expression and induction are reflected by the upregulation of the early response gene c‐fos. The marked and persistent decrease in 5′ deiodinase mRNA content after a‐FGF treatment suggests that a‐FGF may be involved in the regulation of 5′ D‐1 activity in the thyroid. © 1992 Wiley‐Liss, Inc.
On the mechanism of DNA binding by nuclear hormone receptors: A structural and functional perspective
Authors: Freedman Leonard P. , Luisi Ben F. 
Published: May 2005

AbstractThe nuclear hormone receptor DNA‐binding domain consists of two zinc finger‐like modules whose amino acids are highly conserved among the members of the receptor superfamily. In this review, we describe the various genetic, biochemical, and structural experiments that have been carried out primarily for the DNA‐binding domains of the glucocorticoid and estrogen receptors. We describe how the structural and functional information have permitted us to predict properties of the DNA‐binding domains of other nuclear receptors. We postulate how receptors discriminate closely related response elements through sequence‐specific contacts and distinguish symmetry of target sites through protein‐protein interactions. This mechanism explains in part how the receptors regulate diverse sets of genes from a limited repertoire of core response elements. Lastly, we describe the stereochemical basis of nuclear receptor dysfunction in certain clinical disorders. © 1993 Wiley‐Liss, Inc.
Mechanisms of transcriptional activation by steroid hormone receptors
Authors: Baniahmad Aria , Tsai Ming‐Jer 
Published: May 2005

AbstractSteroid hormones are involved in cell growth, development, and differentiation. The hormonal signal is mediated by nuclear receptors which represent a specific class of transcription factors. During the last few years, the cloning of all the major steroid hormone receptors increased our insight into how the hormonal signal converts the receptor into a transcriptional activator. Good progress has been made towards understanding the mechanism of steroid hormone action. In this review we will discuss the role of heat shock proteins in the process of transcriptional activation, the mechanistic differences between the hormone (agonist) and the antihormone (antagonist), the resulting functional consequences, and a possible mode by which transcriptional activation is mediated. © 1993 Wiley‐Liss, Inc.
Cultivation of cell‐polymer cartilage implants in bioreactors
Authors: Freed L. E. , Vunjak‐Novakovic G. , Langer R. 
Published: May 2005

AbstractCartilage implants for potential use in reconstructive or orthopedic surgery can be created by growing isolated cartilage cells (chondrocytes) in vitro on synthetic, biodegradable polymer scaffolds. The scaffolds provide specific three‐dimensional structures which support cell proliferation and biodegrade in a controlled fashion in parallel to cellular regeneration of cartilaginous tissue. Cartilage implants based on chondrocytes and fibrous polyglycolic acid scaffolds were recently shown to closely resemble normal cartilage histologically as well as with respect to cell density and matrix composition (collagen, glycosaminoglycan) [Freed et al., J Biomed Mater Res 27:11–23, 1993a]. These findings form the basis for developing straightforward procedures to obtain implants for clinical use from small, autologous cartilage specimens without any limitations in terms of availability of donor tissue or implant dimensions.Chondrocyte growth and cartilage matrix regeneration on polymer scaffolds are interdependent and also depend on in vitro tissue culture conditions. Under static culture conditions, cell growth rates are diffusionally limited due to increasing cell mass and decreasing effective implant porosity resulting from cartilage matrix regeneration. Optimization of the in vitro culture environment is thus essential for the cultivation of large, clinically useful cartilage implants. Preliminary studies indicate that major improvements can be achieved using bioreactors that provide efficient mass transfer and controlled shear rates at the cell and implant surfaces. © 1993 Wiley‐Liss, Inc.
Reduced shear stress: A major component in the ability of mammalian tissues to form three‐dimensional assemblies in simulated microgravity
Authors: Goodwin T. J. , Prewett T. L. , Wolf David A. , Spaulding G. F. 
Published: May 2005

AbstractBHK‐21 cells were cultured under various shear stress conditions in an Integrated Rotating‐Wall Vessel (IRWV). Shear ranged from 0.5 dyn/cm2 (simulated microgravity) to 0.92 dyn/cm2. Under simulated microgravity conditions, BHK‐21 cells complexed into three‐dimensional cellular aggregates attaining 6 × 106 cells/ml as compared to growth under 0.92 dyn cm2 conditions. Glucose utilization in simulated microgravity was reduced significantly, and cellular damage at the microcarrier surface was kept to a minimum. Thus, the integrated rotating wall vessel provides a quiescent environment for the culture of mammalian cells. © 1993 Wiley‐Liss, Inc.
DNA repair and repair fidelity in metastatic variants of the B16 murine melanoma
Authors: Usmani B. A. , Lunec J. , Sherbet G. V. 
Published: May 2005

AbstractWe have examined the concept of genomic instability in relation to the metastatic progression of low (F1) and high metastasis (BL6, ML8) clones of the B16 mouse melanoma, by using a mutation assay, and DNA strand break repair and repair fidelity assays. The frequency of induced ouabain resistant colonies between the variant cell lines was consistent with the difference between their metastatic properties. Survival data for X‐irradiation and bleomycin were similar among the 3 cell lines. When X‐rays or bleomycin were used to induce strand breakage, no difference was detectable in either the rate or extent of DNA repair using the techniques of alkaline unwinding and alkaline elution for total strand breaks, and neutral elution for double strand breaks. DNA repair fidelity was measured using the PMH16 plasmid. A Kpn I restriction site was used to introduce a break within the gpt gene of the plasmid, prior to transfection. We found that ∼ 100% and ∼ 65% of the highly metastatic ML8 and BL6 clones, respectively, religated the gene with the required fidelity, compared with only ∼ 25% of the low metastasis F1 clones. In summary, the metastatic variants show similar sensitivities to X‐irradiation and bleomycin, but a differential response to EMS. This difference is not reflected in any subsequent DNA strand break religation, but the variants do differ in their fidelity of repair. However, although the fidelity of DNA religation is related to metastatic potential, it is not consistent with the mutation frequency data. © 1993 Wiley‐Liss, Inc.
Drosophila acidic ribosomal protein rpA2: Sequence and characterization
Authors: Olson Pamela F. , Salo Tuula , Garrison Katherine , Fessler John H. 
Published: May 2005

AbstractA cDNA encoding the Drosophila melanogaster acidic ribosomal protein rpA2 was cloned and sequenced. rpA2 is homologous to the Artemia salina acidic ribosomal protein eL12′. In situ hybridization to salivary gland polytene chromosomes localizes the rpA2 gene to band 21C. It is a single copy gene, with an mRNA of 0.8 kb. Two‐dimensional gel electrophoresis of Drosophila ribosomal proteins followed by immuno‐blotting showed that the rpA2 protein has an apparent relative mobility in SDS of 17 kD and an isoelectric point less than pH 5.0. Although the Drosophila gene rp21C may be the same as rpA2, the reported sequences differ. Comparisons of the aligned nucleotide sequences coding for the acidic ribosomal proteins rpA1 and rpA2 of Drosophila with those of other eukaryotes support the view of two separate, though closely related, groups of acidic proteins. Comparison with the Artemia homologues suggests that nucleotide identity may have been conserved by some constraint that acts in addition to the requirement for substantial similarity of amino acid sequences. © 1993 Wiley‐Liss, Inc.
High mannose type N‐linked oligosaccharides on endothelial cells may influence β2 integrin mediated neutrophil adherence in vitro
Authors: Sriramarao P. , Berger Elaine , Chambers J. David , Arfors Karl‐E. , Gehlsen Kurt R. 
Published: May 2005

AbstractWe report herein on the role of N‐linked oligosaccharide processing of endothelial cell surface proteins on the adhesion of neutrophils. Monolayers of human umbilical vein endothelial cells were treated for 24 h with deoxymannojirimycin (DMJ), an inhibitor of golgi mannosidase I, which results in changes in glycoprotein processing, and then incubated with neutrophils to examine their ability to adhere to the treated endothelial cells. Treatment with DMJ, which leads to accumulation of high mannose type oligosaccharides, resulted in a twofold increase in adherence of phorbol ester (PMA) activated neutrophils compared to attachment to untreated endothelial cells. This adherence was likely mediated by the β2 integrin, Mac‐1, and could be specifically inhibited with monoclonal antibodies to ICAM‐1 and to the integrin β2 subunit. Similarly, IL‐1 treatment resulted in a β2 integrin mediated increase in neutrophil adherence to the DMJ treated endothelial cells in a dose dependent manner. However, the IL‐1 induced adherence was not significantly inhibited by the anti‐ICAM‐1 antibody, thus, suggesting the presence of other inducible components on the endothelial cell surface. Our results demonstrate that alterations in glycosylation of N‐linked oligosaccharides, resulting in the synthesis of high mannose type sugars on molecules that may interact with the β2 integrins, leads to an increased adherence of PMA activated neutrophils to endothelial cells. © 1993 Wiley‐Liss, Inc.
Enhanced phosphorylation of a 65 kDa protein is associated with rapid induction of stress proteins in 9L rat brain tumor cells
Authors: Lai Yiu‐Kay , Shen Chi‐Hsiu , Cheng Ting‐Jen , Hou Ming‐Ching , Lee Wen‐Chuan 
Published: May 2005

AbstractInduction of heat‐shock proteins and glucose‐regulated proteins in 9L rat brain tumor cells can be differentially elicited by sodium arsenite, cadmium chloride, zinc chloride, copper sulfate, sodium fluoride, and L‐azetidine‐2‐carboxylic acid. The kinds of stress protein induced by the above chemicals varied considerably, mainly determined by the nature and the concentration of the chemicals, as well as the treatment protocols. In addition, at the concentrations where stress proteins can be induced, the above chemicals were able to suppress general protein synthesis and were cytotoxic. Enhanced phosphorylation of a protein with an apparent molecular weight of 65 kDa was detected during the induction of stress proteins except in azetidine treatments during which uptake of phosphate by the cells was impaired after prolonged incubation. The phosphate moiety on the 65 kDa phosphoprotein appeared to be alkaline‐stable and two‐dimensional gel electrophoresis revealed that the phosphoprotein resolved into four isoforms with isoelectric points ranging from 5.1 to 5.6. Enhanced phosphorylation of the same protein was also detected in heat‐shocked and withangulatin A‐treated 9L cells in which stress proteins were induced. It is suggested that this phosphoprotein may be a common target for heat stress response‐stimulated phosphorylation and important in the further metabolic responses of the cell to stress. © 1993 Wiley‐Liss, Inc.
Protein kinase C: Mediator or inhibitor of insulin action?
Authors: Considine R. V. , Caro J. F. 
Published: May 2005

AbstractThe role of protein kinase C in insulin signal transduction i s controversial It has been postulated that protein kinase C i s activated by insulin and that the kinase i s directly involved in insulin‐mediated metabolic processes. In opposition to this view i s the hypothesis that protein kinase C is not activated by insulin and, more importantly, may be responsible for attenuation of the insulin signal The evidence for and against protein kinase C as a mediator of the insulin signal will be put in perspective followed by discussion of the possible role of the kinase in the pathogenesis of insulin resistance in type II diabetes.
Therapeutic effects of electromagnetic fields in the stimulation of connective tissue repair
Authors: Aaron Roy K. , Ciombor Deborah McK. 
Published: May 2005

AbstractThe therapeutic effects of electric and magnetic fields have been studied largely for their promotion of connective tissue repair. The most widely studied application concerns bone repair and deals with acceleration of the healing of fresh fractures, delayed and non‐unions, incorporation of bone grafts, osteoporosis, and osteonecrosis. More recently the effects of these fields upon the repair of cartilage and soft fibrous tissues have been described. In all these experimental systems and clinical applications an acceleration of extracellular matrix synthesis and tissue healing has been observed. A degree of specificity, in terms of the parameters of applied energy and biological response, is hypothesized.
Regulation of prolactin receptor expression by the tumour promoting phorbol ester 12‐O‐tetradecanoylphorbol‐13‐acetate in human breast cancer cells
Authors: Ormandy Christopher J. , Lee Christine S. L. , Kelly Paul A. , Sutherland Robert L. 
Published: May 2005

AbstractIn both the normal and malignant human breast, cellular sensitivity to the proliferative and differentiative activities of the lactogenic hormones is conferred by expression of the prolactin receptor (PRLR). The PRLR is regulated by steroid hormones; however, recent findings have suggested that PRLR may also be regulated by protein kinase C. To examine this possibility we have studied the effect of various modulators of PKC activity on PRLR binding activity and gene expression in five PRLR positive human breast cancer cell lines. Treatment with 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA), a tumour promoter and modulator of PKC activity, decreased PRLR binding activity in all cell lines examined. In MCF‐7 cells, 10 nM TPA caused a 70% loss of PRLR mRNA after 12 h, paralleled 3 h later by a comparable loss of cell surface PRLR. Mezerein, a non‐phorbol ester modulator of PKC activity and 1,2‐dioctanoyl‐sn‐glycerol, a permeant analogue of the endogenous activator of PKC, also reduced PRLR binding activity, and gene expression in a time‐ and concentration‐dependent manner. Cycloheximide failed to abrogate the TPA‐induced decline in PRLR mRNA levels, indicating that this process was not dependent upon continuing protein synthesis. No change in the stability of PRLR mRNA was observed during 24 h of TPA treatment and TPA reduced the rate of PRLR gene transcription within 3 h of treatment. These results demonstrate that modulators of PKC activity reduce PRLR binding activity and gene expression, implicating this signal transduction pathway in PRLR regulation.
Alterations of collagen mRNA expression during retinoic acid induced chondrocyte modulation: Absence of untranslated α1(I) mRNA in hyaline chondrocytes
Authors: Dietz Uwe , Aigner Thomas , Bertling Wolf M. , von der Mark Klaus 
Published: May 2005

AbstractRetinoic acid (RA) has been shown to rapidly modulate the collagen expression pattern of chondrocytes in vitro at doses of 1–10 μM. Embryonic chicken sternal chondrocytes stop synthesizing the cartilage‐specific type II collagen within 2–4 days of RA treatment and turn on the synthesis of types I and III collagen and fibronectin. While suppression of type II collagen synthesis and onset of type III collagen and fibronectin synthesis have been shown to be regulated at the transcriptional level, conflicting data are available on a possible post‐translational regulation of α1(I) collagen gene expression. In this study we demonstrate by comparing a commonly used α1(I) cDNA probe from the 3′ end of the α1(I) mRNA with a newly prepared α1(I) specific cDNA probe from the 5′ end (p1E1) that—in contrast to previous reports—chicken sternal chondrocytes do not contain untranslated α1(I) mRNA which may become translatable after RA treatment. By in situ hybridization we show the absence of cytoplasmic α1(I) mRNA from chondrocytes and its presence in the perichondrium of sternal cartilage. Perichondral cells might have contaminated sternal chondrocyte preparations, explaining low levels of α1(I) mRNA seen by Northern hybridization and RNase protection assays of chicken sternal cartilage mRNA even with the p1E1 probe. We show by Northern hybridization and metabolic labeling with 3H‐proline followed by SDS‐gel electrophoresis that retinoic acid at 3 μM suppresses type II, IX, and X collagen gene expression within 2 days both at the mRNA and protein level and induces the onset of α1(I), α2(I), and α1(III) expression within 3 days. No expression of CRABP, the cellular retinoic acid binding protein, was seen in RA‐treated or control chondrocytes, indicating that CRABP protein is not involved in the RA‐induced modulation of the chondrocytes.
Cell cycle dependent distribution of proliferating cell nuclear antigen/cyclin and cdc2‐kinase in mouse T‐lymphoma cells
Authors: Brott David A. , Alvey James D. , Bleavins Michael R. , de la Iglesia Felix A. , Lalwani Narendra D. 
Published: May 2005

AbstractThe aim of the present study was to investigate bromodeoxyuridine (BrdU) uptake and coordinated distribution of proliferating cell nuclear antigen (PCNA) and p34‐cdc2‐kinase, two important proteins involved in cell cycle regulation and progression. Flow cytometric analysis of marker proteins in freshly plated mouse T‐lymphoma cells (Yac‐1 cells), using fluorescein isothiocyanate (FITC)‐labeled specific antibodies, showed PCNA distributed throughout the cell cycle with increased intensity in S‐phase. PCNA is essential for cells to cycle through S‐phase and its synthesis is initiated during late G1‐phase before incorporation of BrdU and remains high during active DNA replication. The intensity of PCNA fluorescence increases with the duration of incubation after plating. The cdc2‐kinase was detectable in all phases of the cell cycle and the G2‐M‐phase appears to have the maximum concentrations. The cell cycle analysis of high dose colcemid (2 μg/ml) treated Yac‐1 cells showed an aneuploid or hypodiploid population. Although the G2‐M‐phase seems to be the dominating population in aneuploid cells, the concentrations of cdc2‐kinase were variable in this phase of cell cycle. The colcemid treatment at 25 ng/ml arrested 96% of cells in S‐phase and G2‐M‐phase, but PCNA expression was evident in a portion of the cell population in G2‐M‐phase. Although cells blocked in M‐phase seem to have high levels of cdc2‐kinase, colcemid renders them inactive. From these data, it appears that the down regulation and/or inactivation of cdc2‐kinase could be responsible for the colcemid arrest of cells in M‐phase.
Association of a human H1 histone gene with an H2A pseudogene and genes encoding H2B.1 and H3.1 histones
Authors: Kardalinou Efterpi , Eick Stefan , Albig Werner , Doenecke Detlef 
Published: May 2005

AbstractA cluster of human histone genes was found on three overlapping clones isolated from cosmid and bacteriophage libraries. These three overlapping segments of the human genome comprise genes coding for H3.1, an H2A pseudogene, and an H2B.1 gene downstream of the previously characterized H1.2 gene. The cosmid clone covers 30 kb upstream of the H1.2 gene and overlaps with two phage clones covering the core histone genes and the pseudogene. The same arrangement of an H3 gene, an H2A pseudogene and an H2B gene downstream of an H1 gene has been described within a mouse histone gene cluster [Yang et al.: J Biol Chem 262:17118–17125, 1987; Gruber et al.: Gene 95:303–304, 1990].