Open Access. Powered by Scholars. Published by Universities.®

Medicine and Health Sciences Commons™

Open Access. Powered by Scholars. Published by Universities.®

Dartmouth Scholarship

Discipline
Keyword
Publication Year

Articles 1291 - 1320 of 1400

Full-Text Articles in Medicine and Health Sciences

Cd40 Ligand Expression Is Defective In A Subset Of Patients With Common Variable Immunodeficiency., Mary Farrington, Laura S. Grosmaire, Shigeaki Nonoyama, Susanna H. Fischer, Diane Hollenbaugh, Jeffrey A. Ledbetter, R. J. Noelle Feb 1994

Cd40 Ligand Expression Is Defective In A Subset Of Patients With Common Variable Immunodeficiency., Mary Farrington, Laura S. Grosmaire, Shigeaki Nonoyama, Susanna H. Fischer, Diane Hollenbaugh, Jeffrey A. Ledbetter, R. J. Noelle

Dartmouth Scholarship

Common variable immunodeficiency (CVI) is characterized by hypogammaglobulinemia and recurrent bacterial infections due to failure of CVI B cells to differentiate in vivo into immunoglobulin-secreting plasma cells. We hypothesized that T-cell dysfunction resulting in abnormal contact-mediated B-cell activation may play a prominent role in the failure of CVI B cells to produce specific antibody. We have previously shown that B-cell proliferation and IgE production after stimulation with anti-CD40 and interleukin (IL) 4 were normal in 22 CVI patients evaluated, indicating that CVI B cells respond to signals delivered via CD40. Here we report that CD40 ligand (gp39) mRNA expression by …

Go to article

Cooperative Binding Of Ets-1 And Core Binding Factor To Dna., David Wotton, Jacques Ghysdael, Shuwen Wang, Nancy A. Speck, Michael J. Owen Jan 1994

Cooperative Binding Of Ets-1 And Core Binding Factor To Dna., David Wotton, Jacques Ghysdael, Shuwen Wang, Nancy A. Speck, Michael J. Owen

Dartmouth Scholarship

Two phorbol ester-inducible elements (beta E2 and beta E3) within the human T-cell receptor beta gene enhancer each contain consensus binding sites for the Ets and core binding factor (CBF) transcription factor families. Recombinant Ets-1 and purified CBF bound individually to beta E2 and beta E3, in which the Ets and core sites are directly adjacent. In this report, we show that CBF and Ets-1 bind together to beta E2 and beta E3 and that Ets-1-CBF-DNA complexes are favored over the binding of either protein alone to beta E2. Formation of Ets-1-CBF-DNA complexes increased the affinity of Ets-1-DNA interactions and …

Go to article

Antiparasitic And Antiproliferative Effects Of Indoleamine 2,3-Dioxygenase Enzyme Expression In Human Fibroblasts., Sohan L. Gupta, Joseph M. Carlin, Padma Pyati, Wei Dai, Elmer R. Pfefferkorn, Martin J. Murphy Jr Jan 1994

Antiparasitic And Antiproliferative Effects Of Indoleamine 2,3-Dioxygenase Enzyme Expression In Human Fibroblasts., Sohan L. Gupta, Joseph M. Carlin, Padma Pyati, Wei Dai, Elmer R. Pfefferkorn, Martin J. Murphy Jr

Dartmouth Scholarship

Studies were carried out to evaluate the proposed role of indoleamine 2,3-dioxygenase (INDO) induction in the antimicrobial and antiproliferative effects of gamma interferon (IFN-gamma) in human fibroblasts. The INDO cDNA coding region was cloned in the pMEP4 expression vector, containing the metallothionein (MTII) promoter in the sense (+ve) or the antisense (-ve) orientation. Human fibroblasts (GM637) stably transfected with the sense construct expressed INDO activity after treatment with CdCl2 or ZnSO4, but cells transfected with the antisense construct did not. The growth of Chlamydia psittaci was strongly inhibited in INDO +ve cells but not in INDO -ve cells after treatment …

Go to article

Use Of Yeast Artificial Chromosomes (Yacs) For Studying Control Of Gene Expression: Correct Regulation Of The Genes Of A Human Beta-Globin Locus Yac Following Transfer To Mouse Erythroleukemia Cell Lines., Kenneth Peterson, Galynn Zitnik, Clare Huxley, Christopher Lowrey Dec 1993

Use Of Yeast Artificial Chromosomes (Yacs) For Studying Control Of Gene Expression: Correct Regulation Of The Genes Of A Human Beta-Globin Locus Yac Following Transfer To Mouse Erythroleukemia Cell Lines., Kenneth Peterson, Galynn Zitnik, Clare Huxley, Christopher Lowrey

Dartmouth Scholarship

We demonstrate that transfer of a yeast artificial chromosome (YAC) containing 230 kb of the human beta-globin locus into mouse erythroleukemia cells by fusion results in correct developmental regulation of the human beta-like globin genes. Additionally, we show that early after hybrid formation, human embryonic epsilon- and fetal gamma-globin genes are coexpressed with the adult beta gene but that after 10-20 weeks in culture, globin gene expression switches to predominantly adult. Thus, in contrast to shorter gene constructs, the globin genes of the beta-globin locus YAC are regulated like the chromosomal globin genes. These results indicate that transfer of YACs …

Go to article

Efficient Transcriptional Activation Of Many Simple Modular Promoters By Simian Virus 40 Large T Antigen., Philip W. Rice, Charles N. Cole Nov 1993

Efficient Transcriptional Activation Of Many Simple Modular Promoters By Simian Virus 40 Large T Antigen., Philip W. Rice, Charles N. Cole

Dartmouth Scholarship

Simian virus 40 (SV40) large T antigen is a multifunctional protein which plays central roles during both lytic and transforming infections by SV40. It is a potent transcriptional activator and increases expression from the SV40 late promoter and from several cellular promoters. To understand better the transcriptional activation activity of large T antigen, we examined its ability to transactivate a set of simple modular promoters containing one of four upstream activation sequences coupled with one of three different TATA box sequences originally constructed and studied by Taylor and Kingston (Mol. Cell. Biol. 10:165-175, 1990). Large T antigen activated transcription from …

Go to article

Could Distance Be A Proxy For Severity-Of-Illness? A Comparison Of Hospital Costs In Distant And Local Patients., H G. Welch, E B. Larson, W P. Welch Oct 1993

Could Distance Be A Proxy For Severity-Of-Illness? A Comparison Of Hospital Costs In Distant And Local Patients., H G. Welch, E B. Larson, W P. Welch

Dartmouth Scholarship

We test the hypothesis that hospital costs, after adjusting for DRG mix, are higher in distant patients than in local patients. Data were obtained from the Washington State Commission Hospital Abstract Reporting System (CHARS) and included all patients discharged from 15 metropolitan hospitals in the state of Washington during fiscal year 1987 (N = 181,072).

Go to article

Molecular Cloning Of Infectious Ecotropic Murine Leukemia Virus Ak7 From An Emv-14-Positive Akxl-5 Mouse And The Resistance Of Ak7 To Recognition By Cytotoxic T Lymphocytes., Hillary D. White, William R. Green, Nuria R. Giné Aug 1993

Molecular Cloning Of Infectious Ecotropic Murine Leukemia Virus Ak7 From An Emv-14-Positive Akxl-5 Mouse And The Resistance Of Ak7 To Recognition By Cytotoxic T Lymphocytes., Hillary D. White, William R. Green, Nuria R. Giné

Dartmouth Scholarship

The AKXL-5 recombinant inbred mouse strain is positive for the endogenous ecotropic murine leukemia virus emv-14, the only emv present in its germ line. emv-14 is of particular interest because spleen cells expressing emv-14 virus escape recognition by anti-AKR/Gross virus-specific cytotoxic T lymphocytes. We report here the isolation and characterization of a replication-competent emv clone, pAK7, derived from an AKXL-5 mouse. This clone is novel in that it encodes a variant ecotropic murine leukemia virus that, when expressed in SC.Kb target cells, fails to be recognized efficiently by anti-AKR/Gross virus cytotoxic T lymphocytes. The pAK7 clone can therefore be used …

Go to article

Increased Collagen-Linked Pentosidine Levels And Advanced Glycosylation End Products In Early Diabetic Nephropathy, Paul J. Beisswenger, Lynn L. Moore, Truls Brinck-Johnsen, Thomas J. Curphey Jul 1993

Increased Collagen-Linked Pentosidine Levels And Advanced Glycosylation End Products In Early Diabetic Nephropathy, Paul J. Beisswenger, Lynn L. Moore, Truls Brinck-Johnsen, Thomas J. Curphey

Dartmouth Scholarship

RATIONALE: Advanced glycosylation end products (AGEs) may play an important role in the development of diabetic vascular sequelae. An AGE cross-link, pentosidine, is a sensitive and specific marker for tissue levels of AGEs. OBJECTIVES: To evaluate the role of AGEs in the development of diabetic nephropathy and retinopathy, we studied pentosidine levels and the clinical characteristics of 48 subjects with insulin-dependent diabetes mellitus. Diabetic nephropathy was classified as normal, microalbuminuria, or gross proteinuria, and retinopathy was graded as none, background, or proliferative. NEWLY OBSERVED FINDINGS: Significant elevation of pentosidine (P = 0.025) was found in subjects with microalbuminuria or gross …

Go to article

Cloning And Characterization Of Subunits Of The T-Cell Receptor And Murine Leukemia Virus Enhancer Core-Binding Factor., Shuwen Wang, Qing Wang, Barbara E. Crute, Irena N. Melnikova, Susanna R. Keller, Nancy A. Speck Jun 1993

Cloning And Characterization Of Subunits Of The T-Cell Receptor And Murine Leukemia Virus Enhancer Core-Binding Factor., Shuwen Wang, Qing Wang, Barbara E. Crute, Irena N. Melnikova, Susanna R. Keller, Nancy A. Speck

Dartmouth Scholarship

Moloney murine leukemia virus causes thymic leukemias when injected into newborn mice. A major determinant of the thymic disease specificity of Moloney virus genetically maps to the conserved viral core motif in the Moloney virus enhancer. Point mutations introduced into the core site significantly shifted the disease specificity of the Moloney virus from thymic leukemia to erythroid leukemia (N.A. Speck, B. Renjifo, E. Golemis, T.N. Fredrickson, J.W. Hartley, and N. Hopkins, Genes Dev. 4:233-242, 1990). We previously reported the purification of core-binding factors (CBF) from calf thymus nuclei (S. Wang and N.A. Speck, Mol. Cell. Biol. 12:89-102, 1992). CBF binds …

Go to article

Lithium Phthalocyanine: A Probe For Electron Paramagnetic Resonance Oximetry In Viable Biological Systems., K. J. Liu, P. Gast, M. Moussavi, S. W. Norby, N Vahidi, T Walczak Jun 1993

Lithium Phthalocyanine: A Probe For Electron Paramagnetic Resonance Oximetry In Viable Biological Systems., K. J. Liu, P. Gast, M. Moussavi, S. W. Norby, N Vahidi, T Walczak

Dartmouth Scholarship

Lithium phthalocyanine (LiPc) is a prototype of another generation of synthetic, metallic-organic, paramagnetic crystallites that appear very useful for in vitro and in vivo electron paramagnetic resonance oximetry. The peak-to-peak line width of the electron paramagnetic resonance spectrum of LiPc is a linear function of the partial pressure of oxygen (pO2); this linear relation is independent of the medium surrounding the LiPc. It has an extremely exchange-narrowed spectrum (peak-to-peak line width = 14 mG in the absence of O2). Physicochemically LiPc is very stable; its response to pO2 does not change with conditions and environments (e.g., pH, temperature, redox conditions) …

Go to article

Common Elements In Interleukin 4 And Insulin Signaling Pathways In Factor-Dependent Hematopoietic Cells., Ling-Mei Wang, Achsah D. A D Keegan, Weiqun Li, Gustav E. Lienhard May 1993

Common Elements In Interleukin 4 And Insulin Signaling Pathways In Factor-Dependent Hematopoietic Cells., Ling-Mei Wang, Achsah D. A D Keegan, Weiqun Li, Gustav E. Lienhard

Dartmouth Scholarship

Interleukin 4 (IL-4), insulin, and insulin-like growth factor I (IGF-I) efficiently induced DNA synthesis in the IL-3-dependent murine myeloid cell lines FDC-P1 and FDC-P2. Although these factors could not individually sustain long-term growth of these lines, a combination of IL-4 with either insulin or IGF-I did support continuous growth. The principal tyrosine-phosphorylated substrate observed in FDC cells stimulated with IL-4, previously designated 4PS, was of the same size (170 kDa) as the major substrate phosphorylated in response to insulin or IGF-I. These substrates had phosphopeptides of the same size when analyzed by digestion with Staphylococcus aureus V8 protease, and each …

Go to article

Two Factors That Bind To Highly Conserved Sequences In Mammalian Type C Retroviral Enhancers., Nancy R. Manley, Mary M. O'Connell, Wanwen Sun, Nancy A. Speck, Nancy Hopkins Apr 1993

Two Factors That Bind To Highly Conserved Sequences In Mammalian Type C Retroviral Enhancers., Nancy R. Manley, Mary M. O'Connell, Wanwen Sun, Nancy A. Speck, Nancy Hopkins

Dartmouth Scholarship

The transcriptional enhancers of the Moloney and Friend murine leukemia viruses (MLV) are important determinants of viral pathogenicity. We used electrophoretic mobility shift and methylation interference assays to study nuclear factors which bind to a region of these enhancers whose sequence is identical between Moloney and Friend viruses and particularly highly conserved among 35 mammalian type C retroviruses whose enhancer sequences have been aligned (E. Golemis, N. A. Speck, and N. Hopkins, J. Virol. 64:534-542, 1990). Previous studies identified sites for the leukemia virus factor b (LVb) and core proteins in this region (N. A. Speck and D. Baltimore, Mol. …

Go to article

Sequence Specificity Of The Core-Binding Factor, Irena N. Melnikova, Barbara E. Crute, Shuwen Wang, Nancy A. Speck Apr 1993

Sequence Specificity Of The Core-Binding Factor, Irena N. Melnikova, Barbara E. Crute, Shuwen Wang, Nancy A. Speck

Dartmouth Scholarship

The core-binding factor (CBF) binds the conserved core motif in mammalian type C retrovirus enhancers. We analyzed the phosphate contacts made by CBF on the Moloney murine leukemia virus enhancer by ethylation interference assay. The phosphate contacts span 9 bp centered around the consensus core site. To examine the sequence preferences for CBF binding, we employed the technique of selected and amplified binding sequence footprinting (T. K. Blackwell and H. Weintraub, Science 250:1104-1110, 1990). The consensus binding site for CBF defined by selected and amplified binding sequence footprinting is PyGPyG GTPy.

Go to article

Characterization Of A Protein That Binds Multiple Sequences In Mammalian Type C Retrovirus Enhancers., Wanwen Sun, Mary M. O'Connell, Nancy A. Speck Apr 1993

Characterization Of A Protein That Binds Multiple Sequences In Mammalian Type C Retrovirus Enhancers., Wanwen Sun, Mary M. O'Connell, Nancy A. Speck

Dartmouth Scholarship

Mammalian type C retrovirus enhancer factor 1 (MCREF-1) is a nuclear protein that binds several directly repeated sequences (CNGGN6CNGG) in the Moloney and Friend murine leukemia virus (MLV) enhancers (N. R. Manley, M. O'Connell, W. Sun, N. A. Speck, and N. Hopkins, J. Virol. 67:1967-1975, 1993). In this paper, we describe the partial purification of MCREF-1 from calf thymus nuclei and further characterize the binding properties of MCREF-1. MCREF-1 binds four sites in the Moloney MLV enhancer and three sites in the Friend MLV enhancer. Ethylation interference analysis suggests that the MCREF-1 binding site spans two adjacent minor grooves of …

Go to article

Isolation Of Interleukin 2-Induced Immediate-Early Genes., Carol Beadling, Kirk W. Johnson, Kendall A. Smith Apr 1993

Isolation Of Interleukin 2-Induced Immediate-Early Genes., Carol Beadling, Kirk W. Johnson, Kendall A. Smith

Dartmouth Scholarship

Clonal expansion of antigen-reactive T lymphocytes is driven by the lymphokine interleukin 2 (IL-2). To further elucidate the mechanisms of IL-2 action, we have utilized a differential hybridization procedure to clone IL-2-induced immediate-early genes from an IL-2-stimulated human T-cell cDNA library. To increase the frequency of IL-2-induced transcripts represented in the library, the protein synthesis inhibitor cycloheximide was included during the 2-hr IL-2 stimulation to superinduce gene expression, and the uridine analogue 4-thiouridine was utilized to enable selective purification of newly synthesized transcripts. From the enriched library, we have isolated eight IL-2-induced genes, six of which represent previously unrecognized human …

Go to article

Selective Modulation Of Human Natural Killer Cells In Vivo After Prolonged Infusion Of Low Dose Recombinant Interleukin 2, Michael A. Caligiuri, Christine Murray, Michael J. Robertson, Eunice Wang, Keith Cochran, Christine Cemeron, Peter Schow, Mary E. Ross, Thomas R. Klumpp, Robert J. Soiffer, Kendall A. Smith, Jerome Ritz Jan 1993

Selective Modulation Of Human Natural Killer Cells In Vivo After Prolonged Infusion Of Low Dose Recombinant Interleukin 2, Michael A. Caligiuri, Christine Murray, Michael J. Robertson, Eunice Wang, Keith Cochran, Christine Cemeron, Peter Schow, Mary E. Ross, Thomas R. Klumpp, Robert J. Soiffer, Kendall A. Smith, Jerome Ritz

Dartmouth Scholarship

The immunologic consequences of prolonged infusions of rIL-2 in doses that produce physiologic serum concentrations of this cytokine were investigated. rIL-2 in doses of 0.5-6.0 x 10(6) U/m2 per d (3.3-40 micrograms/m2 per d) was administered by continuous intravenous infusion for 90 consecutive days to patients with advanced cancer. IL-2 concentrations (25 +/- 25 and 77 +/- 64 pM, respectively) that selectively saturate high-affinity IL-2 receptors (IL-2R) were achieved in the serum of patients receiving rIL-2 infusions of 10 micrograms/m2 per d and 30 micrograms/m2 per d. A gradual, progressive expansion of natural killer (NK) cells was seen in the …

Go to article

Indistinguishable Nuclear Factor Binding To Functional Core Sites Of The T-Cell Receptor Delta And Murine Leukemia Virus Enhancers., Juan M. Redondo, Jeffrey L. Pfohl, Cristina Hernandez-Munain, Shuwen Wang, Nancy A. Speck, Michael S. Krangel Nov 1992

Indistinguishable Nuclear Factor Binding To Functional Core Sites Of The T-Cell Receptor Delta And Murine Leukemia Virus Enhancers., Juan M. Redondo, Jeffrey L. Pfohl, Cristina Hernandez-Munain, Shuwen Wang, Nancy A. Speck, Michael S. Krangel

Dartmouth Scholarship

We have previously shown that the delta E3 site is an essential element for transcriptional activation by the human T-cell receptor (TCR) delta enhancer and identified two factors, NF-delta E3A and NF-delta E3C, that bound to overlapping core (TGTGGTTT) and E-box motifs within delta E3. In this study, we show that protein binding to the core motif is necessary but not sufficient for transcriptional activation by the delta E3 element. In contrast, protein binding to the E-box motif does not contribute significantly to enhancer activity. A similar core motif present within the enhancers of T-cell-tropic murine retroviruses has been shown …

Go to article

Modulation Of Cisplatin Sensitivity And Growth Rate Of An Ovarian Carcinoma Cell Line By Bombesin And Tumor Necrosis Factor-Alpha., Seiji Isonishi, Antti P. Jekunen, Doreen K. Hom, Alan Eastman, Peter S. Edelstein, Franz B. Thiebaut, Randolph D. Christen, Stephen B. Howell Oct 1992

Modulation Of Cisplatin Sensitivity And Growth Rate Of An Ovarian Carcinoma Cell Line By Bombesin And Tumor Necrosis Factor-Alpha., Seiji Isonishi, Antti P. Jekunen, Doreen K. Hom, Alan Eastman, Peter S. Edelstein, Franz B. Thiebaut, Randolph D. Christen, Stephen B. Howell

Dartmouth Scholarship

A twofold change in the cisplatin (DDP) sensitivity of 2008 human ovarian carcinoma cells is sufficient to reduce tumor response in vivo. The DDP sensitivity of these cells can be enhanced by activation of the epidermal growth factor and protein kinase C signal transduction pathways. We report here that two endogenous growth factors, bombesin and tumor necrosis factor alpha (TNF alpha), enhanced DDP sensitivity by factors of 1.7 +/- 0.1 (SD)-fold and 1.8 +/- 0.1 (SD)-fold, respectively. Both agents also produced sensitization in an 11-fold DDP-resistant 2008 subline. Neither bombesin nor TNF alpha changed the accumulation of DDP, glutathione content, …

Go to article

A Phorbol Ester Response Element Within The Human T-Cell Receptor Beta-Chain Enhancer., Haydn M. Prosser, David Wotton, Anne Gegonne, Jacques Ghysdael, Shuwen Wang, Nancy A. Speck, Michael J. Owen Oct 1992

A Phorbol Ester Response Element Within The Human T-Cell Receptor Beta-Chain Enhancer., Haydn M. Prosser, David Wotton, Anne Gegonne, Jacques Ghysdael, Shuwen Wang, Nancy A. Speck, Michael J. Owen

Dartmouth Scholarship

The activity of the T-cell receptor beta-chain gene enhancer is increased by activators of the protein kinase C pathway during T-cell activation. Analysis of mutant enhancer constructs identified two elements, beta E2 and beta E3, conferring phorbol ester inducibility. Multimerized beta E2 acted in isolation as a phorbol ester-responsive element. Both beta E2 and beta E3, which contain a consensus Ets-binding site, were shown to bind directly to the product of the c-ets-1 protooncogene. Both regions also bound a second factor, core-binding factor. Mutation of the beta E2 Ets site abolished the inducibility of the beta E2 multimer. beta E2 …

Go to article

On The Mechanism Of Parathyroid Hormone Stimulation Of Calcium Uptake By Mouse Distal Convoluted Tubule Cells, F A. Gesek, A. Friedman Sep 1992

On The Mechanism Of Parathyroid Hormone Stimulation Of Calcium Uptake By Mouse Distal Convoluted Tubule Cells, F A. Gesek, A. Friedman

Dartmouth Scholarship

PTH stimulates transcellular Ca2+ absorption in renal distal convoluted tubules. The effect of PTH on membrane voltage, the ionic basis of the change in voltage, and the relations between voltage and calcium entry were determined on immortalized mouse distal convoluted tubule cells. PTH (10(-8) M) significantly increased 45Ca2+ uptake from basal levels of 2.81 +/- 0.16 to 3.88 +/- 0.19 nmol min-1 mg protein-1. PTH-induced 45Ca2+ uptake was abolished by the dihydropyridine antagonist, nifedipine (10(-5) M). PTH did not affect 22Na+ uptake. Intracellular calcium activity ([Ca2+]i) was measured in cells loaded with fura-2. Control [Ca2+]i averaged 112 +/- 21 nM. …

Go to article

Mechanism Of Calcium Transport Stimulated By Chlorothiazide In Mouse Distal Convoluted Tubule Cells., Frank A. Gesek, Peter A. Friedman Aug 1992

Mechanism Of Calcium Transport Stimulated By Chlorothiazide In Mouse Distal Convoluted Tubule Cells., Frank A. Gesek, Peter A. Friedman

Dartmouth Scholarship

Thiazide diuretics inhibit Na+ and stimulate Ca2+ absorption in renal distal convoluted tubules. Experiments were performed on immortalized mouse distal convoluted tubule (MDCT) cells to determine the mechanism underlying the dissociation of sodium from calcium transport and the stimulation of calcium absorption induced by thiazide diuretics. Control rates of 22Na+ uptake averaged 272 +/- 35 nmol min-1 mg protein-1 and were inhibited 40% by chlorothiazide (CTZ, 10(-4) M). Control rates of 36Cl- uptake averaged 340 +/- 50 nmol min-1 mg protein-1 and were inhibited 50% by CTZ. CTZ stimulated 45Ca2+ uptake by 45% from resting levels of 2.86 +/- 0.26 …

Go to article

Differentiation Of Renal Beta-Intercalated Cells To Alpha-Intercalated And Principal Cells In Culture., Geza Fejes-Tóth, Aniko Náray-Fejes-Tóth Jun 1992

Differentiation Of Renal Beta-Intercalated Cells To Alpha-Intercalated And Principal Cells In Culture., Geza Fejes-Tóth, Aniko Náray-Fejes-Tóth

Dartmouth Scholarship

The renal collecting duct is a heterogenous epithelium consisting of intercalated cells (ICC) and principal cells (PC). The origin of this cellular heterogeneity is not clear. To test the hypothesis that the two cell types might originate from one another, pure populations of ICC (beta subtype) and PC were isolated by fluorescence-activated cell sorting and grown on permeable supports. After the monolayers reached confluence, the expression of ICC- and PC-specific functions and antigens was monitored. Cultures of sorted beta-ICC, in addition to expressing ICC-specific functions (such as an electrogenic H+ secretion) and antigens, progressively acquired PC functions (amiloride-sensitive Na+ transport …

Go to article

Differential Regulation Of Collagenase Gene Expression By Retinoic Acid Receptors--Alpha, Beta And Gamma, Luying Pan, Stephen H. Chamberlain, David T. Auble, Constance E. Brinckerhoff Jun 1992

Differential Regulation Of Collagenase Gene Expression By Retinoic Acid Receptors--Alpha, Beta And Gamma, Luying Pan, Stephen H. Chamberlain, David T. Auble, Constance E. Brinckerhoff

Dartmouth Scholarship

The mechanisms involved in retinoic acid (RA)-mediated regulation of the collagenase gene in a rabbit synovial fibroblast cell line (HIG82) were investigated. When HIG82 cells are cotransfected with expression vectors containing cDNAs for retinoic acid receptor (RAR) α1, β2, or γ1 and collagenase promoter-driven CAT reporter constructs, only RAR-γ1 represses basal CAT expression upon RA treatment, while RAR-α1, β2, and γ1 all suppress phorbol-induced CAT expression. Thus, transcriptional regulation of collagenase by RA is mediated by RARs in an RAR-type specific manner. Using mutatlonal and deletional analysis, we find that interaction between elements within 182 bp collagenase promoter plays an …

Go to article

Cytolytic T Lymphocytes Specific For Tumors And Infected Cells From Mice With A Retrovirus-Induced Immunodeficiency Syndrome., Jennifer G. Erbe, Kathy A. Green, Karen M. Crassi, Herbert C. Morse, W R. Green May 1992

Cytolytic T Lymphocytes Specific For Tumors And Infected Cells From Mice With A Retrovirus-Induced Immunodeficiency Syndrome., Jennifer G. Erbe, Kathy A. Green, Karen M. Crassi, Herbert C. Morse, W R. Green

Dartmouth Scholarship

LP-BM5 retrovirus complex-infected C57BL/6 mice develop immunodeficiency, somewhat analogous to AIDS, termed murine AIDS (MAIDS). After secondary stimulation with syngeneic B-cell lymphomas from LP-BM5-infected mice, C57BL/6 mice produced vigorous CD8+ cytotoxic T lymphocytes specific for MAIDS-associated tumors. An anti-LP-BM5 specificity was suggested because spleen and lymph node cells from LP-BM5-infected mice served as target cells in competition assays, and cells from LP-BM5, but not ecotropic, virus-infected mice functioned as secondary in vitro stimulators to generate cytotoxic T lymphocytes to MAIDS tumors.

Go to article

Transformation Of A Continuous Rat Embryo Fibroblast Cell Line Requires Three Separate Domains Of Simian Virus 40 Large T Antigen., Jiyue Zhu, Philip W. Rice, Lisa Gorsch, Marina Abate, Charles N. Cole May 1992

Transformation Of A Continuous Rat Embryo Fibroblast Cell Line Requires Three Separate Domains Of Simian Virus 40 Large T Antigen., Jiyue Zhu, Philip W. Rice, Lisa Gorsch, Marina Abate, Charles N. Cole

Dartmouth Scholarship

Mouse C3H 10T1/2 cells and the established rat embryo fibroblast cell line REF-52 are two cell lines widely used in studies of viral transformation. Studies have shown that transformation of 10T1/2 cells requires only the amino-terminal 121 amino acids of simian virus 40 (SV40) large T antigen, while transformation of REF-52 cells requires considerably more of large T antigen, extending from near the N terminus to beyond residue 600. The ability of a large set of linker insertion, small deletion, and point mutants of SV40 T antigen to transform these two cell lines and to bind p105Rb was determined. Transformation …

Go to article

Characterization Of The Formate (For) Locus, Which Encodes The Cytosolic Serine Hydroxymethyltransferase Of Neurospora Crassa., C. Robertson Mcclung, Cynthia R. Davis, Karen M. Page, Sylvia A. Denome Apr 1992

Characterization Of The Formate (For) Locus, Which Encodes The Cytosolic Serine Hydroxymethyltransferase Of Neurospora Crassa., C. Robertson Mcclung, Cynthia R. Davis, Karen M. Page, Sylvia A. Denome

Dartmouth Scholarship

Serine hydroxymethyltransferase (SHMT) occupies a central position in one-carbon (C1) metabolism, catalyzing the reaction of serine and tetrahydrofolate to yield glycine and 5,10-methylenetetrahydrofolate. Methylenetetrahydrofolate serves as a donor of C1 units for the synthesis of numerous compounds, including purines, thymidylate, lipids, and methionine. We provide evidence that the formate (for) locus of Neurospora crassa encodes cytosolic SHMT. The for+ gene was localized to a 2.8-kb BglII fragment by complementation (restoration to formate-independent growth) of a strain carrying a recessive for allele, which confers a growth requirement for formate. The for+ gene encodes a polypeptide of 479 amino acids which shows …

Go to article

Mechanisms Of Interference With Simian Virus 40 (Sv40) Dna Replication By Trans-Dominant Mutants Of Sv40 Large T Antigen, Christine M. Bentivoglio, Jiyue Zhu, Charles Cole Mar 1992

Mechanisms Of Interference With Simian Virus 40 (Sv40) Dna Replication By Trans-Dominant Mutants Of Sv40 Large T Antigen, Christine M. Bentivoglio, Jiyue Zhu, Charles Cole

Dartmouth Scholarship

Mutations at multiple sites within the simian virus 40 (SV40) early region yield large T antigens which interfere trans dominantly with the replicative activities of wild-type T antigen. A series of experiments were conducted to study possible mechanisms of interference with SV40 DNA replication caused by these mutant T antigens. First, the levels of wild-type T antigen expression in cells cotransfected with wild-type and mutant SV40 DNAs were examined; approximately equal levels of wild-type T antigen were seen, regardless of whether the cotransfected mutant was trans dominant or not. Second, double mutants that contained the mutation of inA2827, a strong …

Go to article

Adenosine Regulates A Chloride Channel Via Protein Kinase C And A G Protein In A Rabbit Cortical Collecting Duct Cell Line., Erik M. Schwiebert, Katherine H. Karlson, Peter A. Friedman, Paul Dietl, William S. Spielman, Bruce Stanton Mar 1992

Adenosine Regulates A Chloride Channel Via Protein Kinase C And A G Protein In A Rabbit Cortical Collecting Duct Cell Line., Erik M. Schwiebert, Katherine H. Karlson, Peter A. Friedman, Paul Dietl, William S. Spielman, Bruce Stanton

Dartmouth Scholarship

We examined the regulation by adenosine of a 305-pS chloride (Cl-) channel in the apical membrane of a continuous cell line derived from rabbit cortical collecting duct (RCCT-28A) using the patch clamp technique. Stimulation of A1 adenosine receptors by N6-cyclohexyladenosine (CHA) activated the channel in cell-attached patches. Phorbol 12,13-didecanoate and 1-oleoyl 2-acetylglycerol, activators of protein kinase C (PKC), mimicked the effect of CHA, whereas the PKC inhibitor H7 blocked the action of CHA. Stimulation of A1 adenosine receptors also increased the production of diacylglycerol, an activator of PKC. Exogenous PKC added to the cytoplasmic face of inside-out patches also stimulated …

Go to article

Purification Of Core-Binding Factor, A Protein That Binds The Conserved Core Site In Murine Leukemia Virus Enhancers., Shuwen W. Wang, Nancy A. Speck Jan 1992

Purification Of Core-Binding Factor, A Protein That Binds The Conserved Core Site In Murine Leukemia Virus Enhancers., Shuwen W. Wang, Nancy A. Speck

Dartmouth Scholarship

The Moloney murine leukemia virus causes thymic leukemias when injected into newborn mice. A major genetic determinant of the thymic disease specificity of the Moloney virus genetically maps to two protein binding sites in the Moloney virus enhancer, the leukemia virus factor b site and the adjacent core site. Point mutations introduced into either of these sites significantly shifts the disease specificity of the Moloney virus from thymic leukemia to erythroleukemia (N. A. Speck, B. Renjifo, E. Golemis, T. Frederickson, J. Hartley, and N. Hopkins, Genes Dev. 4:233-242, 1990). We have purified several polypeptides that bind to the core site …

Go to article

The Landmark Citation Method: Analysis Of A Citation Pattern As A Collection Assessment Method, Catherine B. Soehner, S Tanner Wray, Daniel T. Richards Dec 1991

The Landmark Citation Method: Analysis Of A Citation Pattern As A Collection Assessment Method, Catherine B. Soehner, S Tanner Wray, Daniel T. Richards

Dartmouth Scholarship

The landmark citation method is a new collection assessment method based on the citation record of a single landmark article. This citation record is developed by identifying sources which cite the landmark article. A bibliography, extracted from the citation record, is then used to complete an assessment of the collection. This method was developed and used to assess the biotechnology collection of the National Library of Medicine. The information gained from this study, in addition to demonstrating the technique, also provided insight into the evolution of the biotechnology literature.

Go to article

First Prev Next Last