Ateş Sevgi | Ankara Universitesi (original) (raw)

Papers by Ateş Sevgi

Research paper thumbnail of Protein-tyrosine phosphatase activity regulates osteoclast formation and function: inhibition by alendronate

Proceedings of the …, Jan 1, 1996

Alendronate (ALN), an aminobisphosphonate used in the treatment of osteoporosis, is a potent inhi... more Alendronate (ALN), an aminobisphosphonate used in the treatment of osteoporosis, is a potent inhibitor of bone resorption. Its molecular target is still unknown. This study examines the effects of ALN on the activity of osteoclast protein-tyrosine phosphatase (PTP; proteintyrosine-phosphate phosphohydrolase, EC 3.1.3.48), called PTPe. Using osteoclast-like cells generated by coculturing mouse bone marrow cells with mouse calvaria osteoblasts, we found by molecular cloning and RNA blot hybridization that PTPe is highly expressed in osteoclastic cells. A purified fusion protein of PTPe expressed in bacteria was inhibited by ALN with an ICso of 2 ,uM. Other PTP inhibitorsorthovanadate and phenylarsine oxide (PAO)-inhibited PTPe with IC50 values of 0.3 I,M and 18 ,tM, respectively. ALN and another bisphosphonate, etidronate, also inhibited the activities of other bacterially expressed PTPs such as PTPcr and CD45 (also called leukocyte common antigen). The PTP inhibitors ALN, orthovanadate, and PAO suppressed in vitro formation of multinucleated osteoclasts from osteoclast precursors and in vitro bone resorption by isolated rat osteoclasts (pit formation) with estimated IC5o values of 10 I,M, 3 ,jM, and 0.05 j,M, respectively. These findings suggest that

Research paper thumbnail of Sexually transmitted diseases in the AIDS era.

Scientific American, Jan 1, 1991

1. Sci Am. 1991 Feb;264(2):62-9. Sexually transmitted diseases in the AIDS era. Aral SO, Holmes K... more 1. Sci Am. 1991 Feb;264(2):62-9. Sexually transmitted diseases in the AIDS era. Aral SO, Holmes KK. Centers for Disease Control, Atlanta. PMID: 1848025 [PubMed - indexed for MEDLINE] MeSH Terms: Acquired Immunodeficiency ...

Research paper thumbnail of Similarity of synthetic peptide from human tumor to parathyroid hormone in vivo and in vitro

Science, Jan 1, 1987

One mechanism considered responsible for the hypercalcemia that frequently accompanies malignancy... more One mechanism considered responsible for the hypercalcemia that frequently accompanies malignancy is secretion by the tumor of a circulating factor that alters calcium metabolism. The structure of a tumor-secreted peptide was recently determined and found to be partially homologous to parathyroid hormone (PTH). The amino-terminal 1-34 region of the factor was synthesized and evaluated biologically. In vivo it produced hypercalcemia, acted on bone and kidney, and stimulated 1,25-dihydroxy-vitamin D3 formation. In vitro it interacted with PTH receptors and, in some systems, was more potent than PTH. These studies support a long-standing hypothesis regarding pathogenesis of malignancy-associated hypercalcemia.

Research paper thumbnail of Biallelic Mutations In PALB2 Cause Fanconi Anemia Subtype FA-N and Predispose to Childhood Cancer

Nature genetics, Jan 1, 2006

Research paper thumbnail of Epidemiology of sexual behavior and sexually transmitted diseases

KK Holmes et al, Jan 1, 1990

Research paper thumbnail of Sexually transmitted diseases, pelvic inflammatory disease, and infertility: an epidemiologic update

Epidemiologic Reviews, Jan 1, 1990

... Vol. 12, 1990 Printed in USA SEXUALLY TRANSMITTED DISEASES, PELVIC INFLAMMATORY DISEASE, AND ... more ... Vol. 12, 1990 Printed in USA SEXUALLY TRANSMITTED DISEASES, PELVIC INFLAMMATORY DISEASE, AND INFERTILITY: AN EPIDEMIOLOGIC UPDATE WILLARD CATES, JR., ROBERT T. ROLFS, JR., AND SEVGI O. ARAL ...

Research paper thumbnail of The dynamic topology of sexually transmitted disease epidemics: implications for prevention strategies

Journal of Infectious Diseases, Jan 1, 1996

Each sexually transmitted disease (STD) epidemic evolves through predictable phases, shaped by a ... more Each sexually transmitted disease (STD) epidemic evolves through predictable phases, shaped by a dynamic interplay among the pathogen, the behaviors of the subpopulations in which it emerges, and the prevention efforts that are developed to limit its impact. As STD epidemics move through these phases, the sexual and social networks that fuel them become located in subpopulations characterized by progressively higher rates of sex partner change and less contact with the health care system. As a result, phase-appropriate prevention strategies and research issues are essential to reducing STDs and their consequences.

Research paper thumbnail of Characterization of a human osteosarcoma cell line (Saos-2) with osteoblastic properties

Cancer Research, Jan 1, 1987

This study examines the osteoblastic properties of the established human osteosarcoma cell line S... more This study examines the osteoblastic properties of the established human osteosarcoma cell line Saos-2. Saos-2 cells inoculated into diffu sion chambers, which were implanted i.p. into nude mice, produced mineralized matrix in 4 of 6 chambers at 8 weeks. In 5 of 6 chambers there was a strong positive alkaline phosphatase reaction. In culture the alkaline phosphatase levels increased with time and cell density, reaching very high levels at confluence: 4-7 /imol/mg protein/min. The cells show a sensitive adenylate cyclase response to parathyroid hormone, 50% effective dose = 2.8 UM,which increases with cell density and is further raised by dexamethasone treatment. They also exhibit typical binding of 1-25-dihydroxyvitamin I), to 3.2S receptor protein with an apparent K¿ of 0.21 IIM;the numbers of sites per cell were 3,300 at 50,000 cells/cm2 and 1,800 at 280,000 cells/cm2. The presence of osteonectin was visual ized with a monoclonal antibody which revealed a reticular pattern on the cell surface. Osteonectin was also detected in the medium by Western blots, migrating at around M, 40,000 in nonreduced gels and M, 44,000 in reduced gels. The Saos-2 cells thus possess several osteoblastic features and could be useful as a permanent line of human osteoblastlike cells and as a source of bone-related molecules.

Research paper thumbnail of Parathyroid hormone-responsive clonal cell lines from rat osteosarcoma

Endocrinology, Jan 1, 1980

Several clonal cell lines from a transplantable rat osteosarcoma, selected on the basis of parath... more Several clonal cell lines from a transplantable rat osteosarcoma, selected on the basis of parathyroid hormone (PTH)-sensitive adenylate cyclase, were established in culture. Bovine PTH-(1-84) (0.1 microM) stimulation of adenylate cyclase varied among clones from 8-fold to none. The level of PTH response was a stable property of each clonal line that was retained through numerous passages in vitro (nearly 3 yr in the oldest clone). Highly PTH-responsive lines had a cuboidal-eliptoid morphology and differed from the nonresponsive lines, which had a more fibroblastic appearance. PTH responsiveness correlated with several properties, presumably associated with the osteoblastic phenotype: elevated alkaline phosphatase activity, synthesis of the gamma-carboxyglutamic acid-containing bone protein, and production of mineralized tumors in host rats. PTH (1.0 nM; 24 h) reduced the alkaline phosphatase activity by 40% when tested in a responsive clone. The acid phosphatase activity of the various cell lines was uniformly low. These osteosarcoma-derived cell lines which are stable in vitro thus seem to reflect the phenotypic heterogeneity observed in the tumor in situ. They could be useful in studies of phenotypic expression, PTH action, and a possible relationship between the two.

Research paper thumbnail of Herpes simplex virus type 2 in the United States, 1976 to 1994

New England Journal …, Jan 1, 1997

Research paper thumbnail of Protein-tyrosine phosphatase activity regulates osteoclast formation and function: inhibition by alendronate

Proceedings of the …, Jan 1, 1996

Alendronate (ALN), an aminobisphosphonate used in the treatment of osteoporosis, is a potent inhi... more Alendronate (ALN), an aminobisphosphonate used in the treatment of osteoporosis, is a potent inhibitor of bone resorption. Its molecular target is still unknown. This study examines the effects of ALN on the activity of osteoclast protein-tyrosine phosphatase (PTP; proteintyrosine-phosphate phosphohydrolase, EC 3.1.3.48), called PTPe. Using osteoclast-like cells generated by coculturing mouse bone marrow cells with mouse calvaria osteoblasts, we found by molecular cloning and RNA blot hybridization that PTPe is highly expressed in osteoclastic cells. A purified fusion protein of PTPe expressed in bacteria was inhibited by ALN with an ICso of 2 ,uM. Other PTP inhibitorsorthovanadate and phenylarsine oxide (PAO)-inhibited PTPe with IC50 values of 0.3 I,M and 18 ,tM, respectively. ALN and another bisphosphonate, etidronate, also inhibited the activities of other bacterially expressed PTPs such as PTPcr and CD45 (also called leukocyte common antigen). The PTP inhibitors ALN, orthovanadate, and PAO suppressed in vitro formation of multinucleated osteoclasts from osteoclast precursors and in vitro bone resorption by isolated rat osteoclasts (pit formation) with estimated IC5o values of 10 I,M, 3 ,jM, and 0.05 j,M, respectively. These findings suggest that

Research paper thumbnail of Sexually transmitted diseases in the AIDS era.

Scientific American, Jan 1, 1991

1. Sci Am. 1991 Feb;264(2):62-9. Sexually transmitted diseases in the AIDS era. Aral SO, Holmes K... more 1. Sci Am. 1991 Feb;264(2):62-9. Sexually transmitted diseases in the AIDS era. Aral SO, Holmes KK. Centers for Disease Control, Atlanta. PMID: 1848025 [PubMed - indexed for MEDLINE] MeSH Terms: Acquired Immunodeficiency ...

Research paper thumbnail of Similarity of synthetic peptide from human tumor to parathyroid hormone in vivo and in vitro

Science, Jan 1, 1987

One mechanism considered responsible for the hypercalcemia that frequently accompanies malignancy... more One mechanism considered responsible for the hypercalcemia that frequently accompanies malignancy is secretion by the tumor of a circulating factor that alters calcium metabolism. The structure of a tumor-secreted peptide was recently determined and found to be partially homologous to parathyroid hormone (PTH). The amino-terminal 1-34 region of the factor was synthesized and evaluated biologically. In vivo it produced hypercalcemia, acted on bone and kidney, and stimulated 1,25-dihydroxy-vitamin D3 formation. In vitro it interacted with PTH receptors and, in some systems, was more potent than PTH. These studies support a long-standing hypothesis regarding pathogenesis of malignancy-associated hypercalcemia.

Research paper thumbnail of Biallelic Mutations In PALB2 Cause Fanconi Anemia Subtype FA-N and Predispose to Childhood Cancer

Nature genetics, Jan 1, 2006

Research paper thumbnail of Epidemiology of sexual behavior and sexually transmitted diseases

KK Holmes et al, Jan 1, 1990

Research paper thumbnail of Sexually transmitted diseases, pelvic inflammatory disease, and infertility: an epidemiologic update

Epidemiologic Reviews, Jan 1, 1990

... Vol. 12, 1990 Printed in USA SEXUALLY TRANSMITTED DISEASES, PELVIC INFLAMMATORY DISEASE, AND ... more ... Vol. 12, 1990 Printed in USA SEXUALLY TRANSMITTED DISEASES, PELVIC INFLAMMATORY DISEASE, AND INFERTILITY: AN EPIDEMIOLOGIC UPDATE WILLARD CATES, JR., ROBERT T. ROLFS, JR., AND SEVGI O. ARAL ...

Research paper thumbnail of The dynamic topology of sexually transmitted disease epidemics: implications for prevention strategies

Journal of Infectious Diseases, Jan 1, 1996

Each sexually transmitted disease (STD) epidemic evolves through predictable phases, shaped by a ... more Each sexually transmitted disease (STD) epidemic evolves through predictable phases, shaped by a dynamic interplay among the pathogen, the behaviors of the subpopulations in which it emerges, and the prevention efforts that are developed to limit its impact. As STD epidemics move through these phases, the sexual and social networks that fuel them become located in subpopulations characterized by progressively higher rates of sex partner change and less contact with the health care system. As a result, phase-appropriate prevention strategies and research issues are essential to reducing STDs and their consequences.

Research paper thumbnail of Characterization of a human osteosarcoma cell line (Saos-2) with osteoblastic properties

Cancer Research, Jan 1, 1987

This study examines the osteoblastic properties of the established human osteosarcoma cell line S... more This study examines the osteoblastic properties of the established human osteosarcoma cell line Saos-2. Saos-2 cells inoculated into diffu sion chambers, which were implanted i.p. into nude mice, produced mineralized matrix in 4 of 6 chambers at 8 weeks. In 5 of 6 chambers there was a strong positive alkaline phosphatase reaction. In culture the alkaline phosphatase levels increased with time and cell density, reaching very high levels at confluence: 4-7 /imol/mg protein/min. The cells show a sensitive adenylate cyclase response to parathyroid hormone, 50% effective dose = 2.8 UM,which increases with cell density and is further raised by dexamethasone treatment. They also exhibit typical binding of 1-25-dihydroxyvitamin I), to 3.2S receptor protein with an apparent K¿ of 0.21 IIM;the numbers of sites per cell were 3,300 at 50,000 cells/cm2 and 1,800 at 280,000 cells/cm2. The presence of osteonectin was visual ized with a monoclonal antibody which revealed a reticular pattern on the cell surface. Osteonectin was also detected in the medium by Western blots, migrating at around M, 40,000 in nonreduced gels and M, 44,000 in reduced gels. The Saos-2 cells thus possess several osteoblastic features and could be useful as a permanent line of human osteoblastlike cells and as a source of bone-related molecules.

Research paper thumbnail of Parathyroid hormone-responsive clonal cell lines from rat osteosarcoma

Endocrinology, Jan 1, 1980

Several clonal cell lines from a transplantable rat osteosarcoma, selected on the basis of parath... more Several clonal cell lines from a transplantable rat osteosarcoma, selected on the basis of parathyroid hormone (PTH)-sensitive adenylate cyclase, were established in culture. Bovine PTH-(1-84) (0.1 microM) stimulation of adenylate cyclase varied among clones from 8-fold to none. The level of PTH response was a stable property of each clonal line that was retained through numerous passages in vitro (nearly 3 yr in the oldest clone). Highly PTH-responsive lines had a cuboidal-eliptoid morphology and differed from the nonresponsive lines, which had a more fibroblastic appearance. PTH responsiveness correlated with several properties, presumably associated with the osteoblastic phenotype: elevated alkaline phosphatase activity, synthesis of the gamma-carboxyglutamic acid-containing bone protein, and production of mineralized tumors in host rats. PTH (1.0 nM; 24 h) reduced the alkaline phosphatase activity by 40% when tested in a responsive clone. The acid phosphatase activity of the various cell lines was uniformly low. These osteosarcoma-derived cell lines which are stable in vitro thus seem to reflect the phenotypic heterogeneity observed in the tumor in situ. They could be useful in studies of phenotypic expression, PTH action, and a possible relationship between the two.

Research paper thumbnail of Herpes simplex virus type 2 in the United States, 1976 to 1994

New England Journal …, Jan 1, 1997