bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bcl‐2 protooncogene expression in cervical carcinoma cell lines containing inactive p53
Authors: Liang Xiao Huan , Mungal Salvatore , Ayscue Andrea , Meissner John D. , Wodnicki Pawel , Hockenbery David , Lockett Stephen , Herman Brian 
Published: May 2005

AbstractBcl‐2 protein expression has been found to block apoptosis and its overexpression has been implicated in lymphoid malignancies where the chromosomal translocation t(14;18) is present. In this study we investigated bcl‐2 transcription and protein expression in cultured cervical carcinoma cell lines and keratinocytes. Western blotting and immunofluorescence microscopy demonstrated bcl‐2 expression in the cytoplasm of 4 out of 5 cervical carcinoma cell lines examined (HeLa, CaSki, C‐33A, and HT‐3, but not SiHa). Bcl‐2 protein expression was undetectable in normal keratinocytes. None of the cell lines examined demonstrated chromosomal translocation or rearrangement at the major breakpoint‐cluster region (MBR) of the bcl‐2 gene using either Southern blot or polymerase chain reaction (PCR) analyses. Northern blot analysis demonstrated low levels of bcl‐2 transcription in HeLa, CaSki, and C‐33A cell lines while reverse transcriptase (RT)‐PCR demonstrated bcl‐2 transcription in all cervical carcinoma cell lines which had bcl‐2 protein expression. Thus, these data suggest that bcl‐2 expression occurs in cervical carcinoma cell lines in the absence of chromosomal translocation or rearrangement of the bcl‐2 gene. However, each of these cervical carcinoma cell lines contains inactive p53, either due to mutation (C‐33A and HT‐3) or via complexation and degradation with human papillomavirus (HPV) 16/18 E6 protein (HeLa and CaSki). Thus, functional p53, which can induce apoptosis in certain cells, is not present in these cervical cells which have increased bcl‐2 expression. Increased bcl‐2 expression under conditions of p53 inactivation may provide cells with a selective advantage for survival and consequently play a role in the development of cervical carcinogenesis.
Analysis of cell‐mediated mineralization in culture of bone‐derived embryonic cells with neurofibromatosis
Authors: Klein B. Y. , Rojansky N. , Gal I. , Shlomai Z. , Liebergall M. , Ben‐Bassat H. 
Published: May 2005

Abstractvon Recklinghausen neurofibromatosis (NF1) is an autosomal dominant genetic disorder associated with congenital pseudoarthrosis and with short stature. To examine whether the NF1 phenotype includes functional osteogenic defects, embryonic bone‐derived cells affected with NF1 were tested in culture for specific alkaline phosphatase (ALP) activity and cell‐mediated mineralization and compared with other embryonic bone derived cells. NF1 showed a relatively higher specific ALP activity, which has further increased in response to dexamethasone + β‐glycerophosphate (βGP) (Dex medium) coordinately with a decrease in cell proliferation. In the control group, two samples showed increased ALP activity, one showed decreased activity and the forth one did not show any change in ALP. NF1 cells were distinguished from other cells regarding day 21 mineralization, they did not mineralize when cultured with ascorbate alone in the absence of Dex medium, whereas control cells did mineralize. Adding βGP resulted in mineralization by NF1 cells but less than in other cells. In addition, NF1 cells responded to dexamethasone by increasing the βGP‐induced mineralization, as opposed to cells from other embryonic bones, which either did not respond or have even decreased mineralization under dexamethasone. Upon cis‐hydroxyproline exposure, Dex medium has also distinguished NF1 cell ALP activity from that of other cell origins. Inhibition of respiratory complex II by malonate showed that most embryonic bone‐derived cells of 12 weeks gestation are malonate resistant; thus, malonate selection was ineffective. This is in contrast to rat marrow stromal cells previously shown to undergo mineralizing cell enrichment in response to malonate. Exposure to levamisole, of Dex‐treated cells, at days 0–11 has inhibited day 21 mineralization in all tested cultures in spite of the increase in day 11‐specific ALP activity. Both malonate and levamisole did not distinguish NF1 cells from the osteogenic phenotype of other cells. Essentially embryonic bone‐derived cells from 12 weeks gestation, cultured in the absence of βGP, retained their mineralization capacity, which does not increase under dexamethasone, as distinguished from NF1 cells which require βGP for mineralization and positively respond to dexamethasone. Therefore, bone‐derived NF1 cells may be useful for studying the regulation of the mineralization process.
1α,25‐dihydroxyvitamin D3 rapidly alters phospholipid metabolism in the nuclea envelope of osteoblasts
Authors: Sorensen A. M. , Baran D. T. 
Published: May 2005

Abstract1α,25‐Dihydroxyvitamin D3 (1α, 25‐(OH)2D3) has been shown to increase cytosolic calcium and inositol trophosphate levels in rat osteosarcoma cells (ROS 17/2.8) and to increase nuclear calcium in these cells. To determine the mechanism(s) of 1α, (OH)2D3‐induced changes in the calcium, the effect of the hormone on phospholipid metabolism in isolated osteoblast nuclei wa assessed. 1α,25 (OH)2D3, 20 nM, increased inositol triphosphate levels in the nuclei after 5 min of treatment. The biologically inactive epimer, 1β,25‐(OH)2D3, had no significant effect on inositol triphosphate levels. ATP, 1 mM, also increased inositol triphosphate levels in the isolated nuclei after 5 min. 1α,25‐(OH)2D3, 20 nM, increased calcium in the isolated nuclei in the presence but not in the absence of extranuclear calcium with 5 min. Nuclear calcium was also increased within 5 min by ATP, 1 mM, and inositol triphosphate, 1 mM. The effects of ATP on nuclear calcium was not additive with 1α, 25‐(OH)2D3, suggesting that these two agents increase nuclear calcium in these osteoblast‐like cells by similar mechanisms. In summary, 1α,25‐(OH)2D3 amd ATP rapidly increase inositol triphosphate levels in isolated from ROS 17/2.8 cells. The hormone, the nucleotide, and the inositol phospholipid nuclear calcium. Thus, the 1α,25‐(OH)2D3 and ATP effects of nuclear calcium may be mediated by changes in phospholipid metabolism in the nuclei of these osteoblastlike cells. © Wiley‐Liss, Inc.
Zeolite a inhibits osteoclast‐mediated bone resorption in vitro
Authors: Schütze N. , Oursler M. J. , Nolan J. , Riggs B. L. , Spelsberg T. C. 
Published: May 2005

AbstractThe effects of Zeolite A on Bone resorbing activity of highly purified avian osteoclasts were analyzed. The present study demonstrates that when 100 pg/ml of acid‐treated Zeolite A is added to the media the number of pits per osteoclast is reduced 3‐fold at 24h after treatment. Secreted cathepsin B enzyme activity was also reduced 3‐fold. A similar reduction in pit number per osteoclast was measured following 48 h of treatment with Zeolite A but there appeared to be less reduction of cathepsin B enzyme activity. The effects on pit number and cathepsin B Protein activity were Zeolit dose dependent. The structure of the compound seemed to be responsible for the effects measured since compounds used to represent constituents of Zeolite A (silicon dioxide and aluminum cholride) failed to inhibit bone resorption or reduce the level of secreted cathepsin B enzyme activity. Thus the molicular architecture of Zeolite A or a derivative there of appears to be inportant. In conclusion, the data indicate that Zeolite A can inhibit bone resorption. Together with previous data on osteoblasts, this might suggest a potential positive activity of intact Zeolite A or a partial substructure of Zeolite A on bone turnover. © Wiley‐Liss, Inc.
Molecular anatomy of an endodermal gland: Investigations on mucus glycoproteins and cell turnover in Brunner's glands of didelphis verginiana using lectins and PCNA immunoreactivity
Authors: Schumacher U. , Krause W. J. 
Published: May 2005

AbstractBrunner's glandsl are located in the submucosa of the proximal duodenum and are unique to mammalian species. The North American opossum (Didelphis virginiana) is generally regarded as a prototype marsupial that closely resembles fossil didelphids which can be placed at the beginning of mammalian evolution. The current investigation provided an opportunity for the analysis of secretory products from these glands in a species thought to be more closely related to earlier evolutionary forms. Extracts of Brunner's glands were subjected to SDS‐PAGE and Western Blotting. The results indicate the presence of two high molecular weight PAS‐positive glycoprotein bands. In addition to these two PAS‐positive bands, several other glycoprotein bands were detected in the high molecular weight range that bind several lectins which typically recognize O‐linked carbohydrates indicative of mucus type glycoproteins. The same lectins bind to glandular structures in tissue sections. Comparison of lectin binding sites with the pyloric glands of the stomach and duodenal goblet cells indicates that brunner's glands carbohydrate residues resemble those of the pyloric glands more closely than those of the duodenal goblet cells. The low cell turnover rate in brunner's glands is in contrast to the rapid turnover rate of goble cell precursors in the duodenal crypts. The mucus composition and the cell turnover rate correlate well with embryological data and suggest that Brunner's glands of Didelphis evolved from an epithelium more closely associated closely associated with the stomach than that of the duodenum as the topography of the gland would suggest. © Wiley‐Liss, Inc.
Developmental changes in the activity and cellular localization of hepatic casein kinase II in the rat
Authors: Gruppuso Philip A. , Boylan Joan M. 
Published: May 2005

AbstractAbstract The activity and cellular localization of hepatic casein kinase II(CKII) was examined during late fetal development in the rat. Cultured fetal hepatocytes displayed constitutive CKII activity which was not further activated by growth factor exposure. Similarly, fetal liver CKII showed approximately fivefold greater activity than adult liver. The fetal hepatic activity was, to a large degree, localized to a nuclear fraction. Postnuclear cytosol preparations from fetal and adult liver showed similar CKII activity. In all cases, FPLC ion exchange chromatography followed by Western immunoblotting showed that immunoreactive CKII coincided with kinase activity. However, Parallel determinations of CKII activity and immunoreactive CKII levels showed a higher(five‐to sixfold) CKII specific activity in nuclear extracts compared to cytosol. In summary, fetal hepatic CKII demonstrates coincident nuclear localization and activation. We hypothesize that the regulation of hepatic CKII is relevant to the mitogen‐independent proliferation displayed by fetal rat hepatocytes. © Wiley‐Liss, Inc.
Apoptosis in anititumor strategies: Modulation of cell cycle or differentiation
Authors: Darzynkiewicz Zbigniew 
Published: May 2005

AbstractThere is a strong evidence that administration of antitumor drugs triggers apoptotic death of target cells. A characteristic feature of appotosis is active participation of the affected cell in its demise. Attempts have been made, therefore, to potentiate the cytotoxicity of a variety of agents by modulating the propensity of cells to respond by apoptosis. Several strategies to enhance apoptosis that involve modulation of the cell cycle or differentiation are discussed. Loss of control of the G1 checkpoint in tumor cells allows one to design treatments that arrest normal cells at the checkpoint and attempt to selectively kill tumor cells with S phase specific drugs. The possibility of a restoration of the apoptosis triggering function of the tumor suppressor gene p53 when the G1 checkpoint function is abolished is expected to increase tumor cells' sensitivity to S phase poisons. Because induction of apoptosis by many antitumor drugs is cell cycle phase specific, drug combinations that preferentially trigger apoptosis at different phases of the cycle, or recruitment of cells to the sensitive phase, offer another antitumor strategy. There is also evidence that apoptosis is potentiated when cell differentiation is triggered follwing DNA damage. This observation suggests that strategies which combine DNA damaging and differentiating drugs, under conditions where the latter are administered following DNA damage caused by the former, may be successful.
Ceramide: A stress signal and mediator of growth suppression and apoptosis
Authors: Obeid Lina M. , Hannun Yusuf A. 
Published: May 2005

AbstractA novel pathway termed the sphingomyelin cycle has been identified whereby membrane sphingomyelin is hydrolyzed in response to multiple extracellular stimuli (such as tumor necrosis factor α) which cause activation of regulated sphingomyelinases. The product, ceramide, has emerged as a second messenger that mediates many of the cellular effects of these extracellular stimuli. An intriguing relation exists between activation of the sphingomyelin cycle and the action of multiple stress stimuli that induce growth arrest and programmed cell death. Exogenously administered ceramide mimics these growth‐suppressing effects, including the induction of apoptosis. This review will highlight the role of the sphingomyelin cycle in signal transduction and will focus on the role and function of ceramide in the regulation of cell growth in general and apoptosis specifically.
Concept and organization of a clinical gene therapy lab
Authors: Kittler Ellen L. W. , Quesenberry Peter J. 
Published: May 2005

AbstractDesigning a dedicated clinical facility to meet the needs of existing and developing Gene Therapy Protocols presents a unique challenge. Here, we review some of the issues we faced and share some of our design concepts. An optimal Clinical Gene Therapy Lab must meet relevant regulatory guidelines, interface with other hospital labs as well as the clinic and patient care areas, be efficient and flexible in utilization of space, and have the potential to meet future needs without continual renovation. As clinical science expands to include more gene transfer approaches, specific laboratory areas for this type of work will become increasingly necessary.
Possible involvement of focal adhesion kinase, p125FAK, in osteoclastic bone resorption
Authors: Tanaka Sakae , Takahashi Naoyuki , Udagawa Nobuyuki , Murakami Hiroshi , Nakamura Ichiro , Kurokawa Takahide , Suda Tatsuo 
Published: May 2005

AbstractInvolvement of tyrosine phosphorylation in osteoclastic bone resorption was examined using osteoclast‐like multinucleated cells prepared from co‐cultures of mouse osteoblastic cells and bone marrow cells in the presence of 1α,25‐dihydroxyvitamin D3. When osteoclast‐like cells were plated on culture dishes in the presence of 10% fetal bovine serum, they were sharply stained in their peripheral region by anti‐phosphotyrosine antibody. Western blot analysis revealed that 115‐to 130‐kD proteins were tyrosine‐phosphorylated in osteoclast‐like cells. Using immunoprecipitation and immunoblotting, one of the proteins with 115–130 kD was identified as focal adhesion kinase (p125FAK), a tyrosine kinase, which is localized in focal adhesions. Immunostaining with anti‐p 125FAK antibody revealed that p125FAK was mainly localized at the periphery of osteoclast‐like cells. Herbimycin A, a tyrosine kinase inhibitor, not only suppressed tyrosine phosphorylation of p125FAK but also changed the intracellular localization of p125FAK and disrupted a ringed structure of F‐actin‐containing podosomes in osteoclast‐like cells. Antisense oligodeoxynucleotides to p125FAK inhibited dentine resorption by osteoclast‐like cells, whereas sense oligodeoxynucleotides did not. These results suggest that p125FAK is involved in osteoclastic bone resorption and that tyrosine phosphorylation of p125FAK is critical for regulating osteoclast function.
Differential regulation of p34cdc2 and p33cdk2 by transforming growth factor‐β1 in murine mammary epithelial cells
Authors: Fautsch Michael P. , Eblen Scott T. , Anders Robert A. , Burnette Rebekah J. , Leof Edward B. 
Published: May 2005

AbstractCyclin‐dependent kinases (cdks) are a family of proteins whose function plays a critical role in cell cycle traverse. Transforming growth factor‐β1 (TGF‐β1) is a potent growth inhibitor of epithelial cells. Since cdks have been suggested as possible biochemical markers for TGF‐β growth inhibition, we investigated the effect of TGF‐β1 on cdc2 and cdk2 in a normal mouse mammary epithelial cell line (MME) and a TGF‐β‐resistant MME cell line (BG18.2). TGF‐β1 decreases newly synthesized cdc2 protein levels within 6 h after addition. Coincident with this decrease in newly synthesized cdc2 protein was a marked reduction in its ability to phosphorylate histone H1. This decrease in kinase activity is not due to a change in steady‐state levels of cdc2 protein, since mRNA and total protein levels of cdc2 are not reduced until 12 h after TGF‐β1 addition. This suggests that the kinase activity of cdc2 is dependent on newly synthesized cdc2 protien. Moreover, the protein synthesis of another cyclin‐dependent kinase, cdk2, is not effected by TGF‐β1 addition, but its kinase activity is substantially reduced. Thus, it appears that TGF‐β decreases the kinase activity of both cdc2 and cdk2 by distinct mechanisms.
Dysfunction of protein kinase FA/GSK‐3α in lymphocytes of patients with schizophrenic disorder
Authors: Yang Shiaw‐Der , Yu Jau‐Song , Lee Tsong‐Tze , Yang Chuan‐Ching , Ni Mei‐Hui , Yang Yong‐Yi 
Published: May 2005

AbstractAs compared to normal people, the lymphocytes of patients with schizophrenia were found to have an impairment of ATP. Mg‐dependent protein phosphatase activation. More importantly, the impaired protein phosphatase activation in the lymphocytes of schizophrenic patients could be consistently and completely restored to normal by exogenous pure protein kinase FA/glycogen synthase kinase‐3α (kinase FA/GSK‐3α) (the activating factor of ATP.Mg‐dependent protein phosphatase), indicating that the molecular mechanism for the impaired protein phosphatase activation in schizophrenic patients may be due to a functional loss of kinase FA/GSK‐3α immunoblotting and kinase activity analysis in an anti‐kinase FA/GSK‐3α immunoprecipitate further demonstrate that both cellular activities and protein levels of kinase FA/GSK‐3α in the lymphocytes of schizophrenic patients were greatly impared as compared to normal controls. Statistical analysis revealed that the lymphocytes isolated from 37 normal people contain kinase FA/GSK‐3α activity in the high levels of 14.8 ± 2.4 units/mg of cell protein, whereas the lymphocytes of 48 patients with schizophrenic disorder contain kinase FA/GSK‐3α activity in the low levels of 2.8 ± 1.6 units/mg, indicating that the different levels of kinase FA/GSK‐3α activity between schizophrenic patients and normal people are statistically significant. Taken together, the results provide intial evidence that patients with schizophrenic disorder may have a common impairment in the protein levels and cellular activities of kinase FA/GSK‐3α, a multisubstrate protein kinase and a multisubstrate protein phosphatase activator in their lymphocytes. © 1995 Wiley‐Liss, Inc.
Changes associated with tyrosine phosphorylation during short‐term hypoxia in retinal microvascular endothelial cells in vitro
Authors: Koroma Barba M. , de Juan Eugene 
Published: May 2005

AbstractThe occlusion of capillary vessels results in low oxygen tension in adjacent tissues which triggers a signaling cascade that culminates in neovascularization. Using bovine retinal capillary endothelial cells (BRCEC), we investigated the effects of short‐term hypoxia on DNA synthesis, phosphotyrosine induction, changes in the expression of basic fibroblast growth factor receptor (bFGFR), protein kinase C (PKCα), heat shock protein 70 (HSP70), and SH2‐containing protein (SHC). The effect of protein tyrosine kinase (PTK) and phosphatase inhibitors on hypoxia‐induced phosphotyrosine was also studied. Capillary endothelial cells cultured in standard normoxic (pO2 = 20%) conditions were quiesced in low serum containing medium and then exposed to low oxygen tension or hypoxia (pO2 = 3%) in humidified, 5% CO2, 37°C, tissue culture chambers, on a time‐course of up to 24 h. DNA synthesis was potentiated by hypoxia in a time‐dependent manner. This response positively correlated with the cumulative induction of phosphotyrosine and the downregulation of bFGFR (Mr ∼ 85 kDa). Protein tyrosine kinase inhibitors, herbimycin‐A, and methyl 2,5‐dihydroxycinnamate, unlike genistein, markedly blocked hypoxia‐induced phosphotyrosine. Prolonged exposure of cells to phosphatase inhibitor, sodium orthovanadate, also blocked hypoxia‐induced phosphotyrosine. The expression of HSP70, PKCα, and SHC were not markedly altered by hypoxia. Taken together, these data suggest that short‐term hypoxia activates endothelial cell proliferation in part via tyrosine phosphorylation of cellular proteins and changes in the expression of the FGF receptor. Thus, endothelial cell mitogenesis and neovascularization associated with low oxygen tension may be controlled by abrogating signaling pathways mediated by protein tyrosine kinase and phosphatases. © 1995 Wiley‐Liss, Inc.
Role of apoptosis in the regulation of virus‐induced T cell responses, immune suppression, and memory
Authors: Welsh Raymond M. , Selin Liisa K. , Razvi Enal S. 
Published: May 2005

AbstractApoptosis is an important mechanism enabling the selection of the non‐self‐reactive T cell repertoire and for maintaining homeostasis in the immune system after it has expanded to combat infections. Highly activated, proliferating T cells become susceptible to apoptosis driven by a number of stimuli, and T cells activated during a viral infection become susceptible to “activation induced cell death” after repeated stimulation through the T cell receptor (TcR). This is a major mechanism for the immune deficiencies observed during many viral infections. During infections with a high antigen load this can lead to a selective deletion of virus‐specific cytotoxic T lymphocytes (CTL) and to the establishment of persistent infection. More commonly, the CTL control the infection first, and high levels of apoptosis in the expanded lymphocyte population occur after antigen and growth factors become limiting. This cell death does not seem to depend on TcR specificity, as the residual population contains a remarkably stable population of memory CTL precursors that approximate the frequency per CD8 cell of that seen during the peak of the acute infection. Subsequent infections with heterologous viruses result in an expansion and then an apoptotic elimination of T cells, with the consequence being a reduction in precursor CTL specific for the first virus. Thus, apoptosis shapes the quality and quantity of T cell memory. © 1995 Wiley‐Liss, Inc.