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Erhamamcı S, Sager S, Asa S, Uslu L, Akgun E, Sonmezoglu K. Insulinoma maligno: PET/TC con 18F-DOPA y 68Ga-DOTATATE y tratamiento con 177Lu-DOTATATE. Rev Esp Med Nucl Imagen Mol 2020; 39:383-386. [DOI: 10.1016/j.remn.2019.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 11/28/2019] [Accepted: 12/02/2019] [Indexed: 11/30/2022]
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Himmel A, Sager S, Sundmacher K. Flexibler Betrieb von Biogasanlagen mittels inversionsbasierter zeitoptimaler Steuerung. CHEM-ING-TECH 2018. [DOI: 10.1002/cite.201855221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- A. Himmel
- Otto-von-Guericke-Universität; Institut für Verfahrenstechnik; Universitätsplatz 2 39106 Magdeburg Deutschland
| | - S. Sager
- Otto-von-Guericke-Universität; Institut für Mathematische Optimierung; Universitätsplatz 2 39106 Magdeburg Deutschland
| | - K. Sundmacher
- Otto-von-Guericke-Universität; Institut für Verfahrenstechnik; Universitätsplatz 2 39106 Magdeburg Deutschland
- Max-Planck-Institut für Dynamik komplexer technischer Systeme; Prozesstechnik; Sandtorstraße 1 39106 Magdeburg Deutschland
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Uslu L, Sen F, Sager S, Halaç M. Extensive peritoneal and pleural lymphomatosis in a patient with Burkitt lymphoma revealed with 18F-FDG PET/CT. Nuklearmedizin 2018. [DOI: 10.1055/s-0038-1625740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Himmel A, Rihko-Struckmann L, Sager S, Sundmacher K. Modellgestützte optimale Steuerung von Biogasanlagen. CHEM-ING-TECH 2016. [DOI: 10.1002/cite.201650122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Zincirkeser S, Sahin E, Halac M, Sager S. Standardized Uptake Values of Normal Organs on 18F-Fluorodeoxyglucose Positron Emission Tomography and Computed Tomography Imaging. J Int Med Res 2016; 35:231-6. [PMID: 17542410 DOI: 10.1177/147323000703500207] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Standardized uptake values (SUVs) of normal organs were evaluated by 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography and computed tomography (PET-CT) scanning. Seventy patients (38 men and 32 women) with no non-physiological 18F-FDG uptake participated in the study. All patients fasted for at least 4 h before PET-CT imaging and their fasting blood glucose levels were within the normal range. Image acquisition was performed after intravenous administration of 18F-FDG and images were obtained from the vertex to the upper thigh region. The SUVs of various organs were determined from the transverse views. The uptake of 18F-FDG was highest in the cerebrum, cerebellum, myocardium, tonsils, liver and spleen in both sexes. Having knowledge of the physiological uptake of 18F-FDG and normal organ SUVs is required for the correct interpretation of whole-body 18F-FDG-PET-CT studies.
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Affiliation(s)
- S Zincirkeser
- Nuclear Medicine and PET Centre, Medical School, Gaziantep University, Gaziantep, Turkey.
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Akcali C, Zincirkeser S, Erbagcý Z, Akcali A, Halac M, Durak G, Sager S, Sahin E. Detection of Metastases in Patients with Cutaneous Melanoma Using FDG-PET/CT. J Int Med Res 2016; 35:547-53. [PMID: 17697533 DOI: 10.1177/147323000703500415] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
This study aimed to detect metastases in patients with stage III or IV cutaneous melanoma by 18F-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT). Thirty-nine patients with clinically evident stage III or IV melanoma underwent whole-body FDG-PET/CT scans for metastatic disease and these results were compared with those of biopsy. Scans for 38 of the patients were evaluated; one patient's scan could not be evaluated. There were 11 true-positive, two false-positive, 24 true-negative and one false-negative scans for the detection of melanoma metastases, with sensitivity 91%, specificity 92%, accuracy 92%, and positive and negative predictive values 84% and 96%, respectively. False-positive FDG-PET/CT scans were due to sarcoidosis in the lung and infected cyst in the liver. It is concluded that FDG-PET/CT scanning has high sensitivity and specificity for detecting stage III or IV metastatic melanoma.
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Affiliation(s)
- C Akcali
- Department of Dermatology, Medical School, Gaziantep University, Gaziantep, Turkey.
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Vatankulu B, Yilmaz Aksoy S, Asa S, Sager S, Sayman H, Halac M, Sonmezoglu K. Accuracy of FDG-PET/CT and paraneoplastic antibodies in diagnosing cancer in paraneoplastic neurological syndromes. Rev Esp Med Nucl Imagen Mol 2016. [DOI: 10.1016/j.remnie.2015.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Yilmaz S, Aliyev A, Ekmekcioglu O, Ozhan M, Uslu L, Vatankulu B, Sager S, Halaç M, Sönmezoğlu K. Comparison of FDG and FDG-labeled leukocytes PET/CT in diagnosis of infection. Nuklearmedizin 2015; 54:262-71. [PMID: 26503832 DOI: 10.3413/nukmed-0724-15-02] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 10/07/2015] [Indexed: 11/20/2022]
Abstract
UNLABELLED The aim of this study is to compare FDG and FDG-labeled leukocyte (WBC) PET/CT in the diagnosis of infection using different SUV and visual thresholds for interpretation. Patients, material, method: 49 consecutive patients (27 men, 22 women, mean age: 55.7 years, range: 16-89 years) with suspected musculoskeletal infection (n = 34), vascular graft infection (n = 5), aortitis (n =1 ), endocarditis (n = 1), mass lesion which is suspicious for infection or malignity (n = 6), and fever of unknown origin (n = 2) underwent both FDG and WBC-PET/CT. Images were evaluated by both visual analysis (grade 1-3) according to uptake intensity and quantitative grading (grade 1-3) based on lesion to background SUVmax values. Final diagnosis was made by histopathological, microbiological analysis or clinical-radiological work-up. RESULTS The diagnosis of infection was made in total 24 patients, of whom 14 were diagnosed by histopathological and the rest by clinical-radiological work-up. WBC-PET/CT imaging with the visual threshold of 1b as infection positivity (for truncal lesions uptake equivalent to liver or lumbar vertebrae uptake; for extremity lesions uptake significantly higher than neighbouring soft tissue uptake or higher than neighbouring bone marrow uptake) was found to have the highest diagnostic accuracy (AUC: 0.874, CI: 0.771-0.997, p < 0.001). The optimal SUV threshold was found to be 8.8 (p = 0.006; sensitivity: 72.7%, specificity: 82.8) and 5.3 (p < 0.001; sensitivity: 81.8%, specificity: 79.3%) for FDG and WBC-PET/CT, respectively by ROC curve analysis. CONCLUSION WBC-PET/CT is more valuable than FDG PET/CT in the imaging of infection. Visual threshold of >1b seems to be more suitable for detection of infection.
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Affiliation(s)
- S Yilmaz
- Sabire Yilmaz, Ankara Atatürk Research and Training Hospital - Nuclear Medicine, Ankara 06608, Turkey,
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Uslu L, Asa S, Sager S, Halaç M. Multiple cardiac masses and distant metastatic foci in a patient with high grade pleomorphic sarcoma of the heart revealed by follow-up FDG PET/CT. Nuklearmedizin 2014. [DOI: 10.1055/s-0039-3399412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Undifferentiated high grade pleomorphic sarcoma of the heart is a rare clinical entity and efficiency of FDG PET/CT in this tumour was not well studied.
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Affiliation(s)
- L. Uslu
- Department of Nuclear Medicine, Istanbul University Cerrahpasa Medical Faculty, Istanbul, Turkey
| | - S. Asa
- Department of Nuclear Medicine, Istanbul University Cerrahpasa Medical Faculty, Istanbul, Turkey
| | - S. Sager
- Department of Nuclear Medicine, Istanbul University Cerrahpasa Medical Faculty, Istanbul, Turkey
| | - M. Halaç
- Department of Nuclear Medicine, Istanbul University Cerrahpasa Medical Faculty, Istanbul, Turkey
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Uslu L, Asa S, Sager S, Halaç M. Multiple cardiac masses and distant metastatic foci in a patient with high grade pleomorphic sarcoma of the heart revealed by follow-up FDG PET/CT. Nuklearmedizin 2014; 53:N8-N9. [PMID: 24777356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 06/30/2013] [Indexed: 06/03/2023]
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Sager S, Engin B, Kutlubay Z, Asa S, Sager SG, Gucluer B, Kanmaz B. PET/CT imaging of HIV-negative Kaposi's sarcoma. Ir J Med Sci 2013; 182:745-6. [PMID: 23526254 DOI: 10.1007/s11845-013-0936-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 03/04/2013] [Indexed: 11/28/2022]
Affiliation(s)
- S Sager
- Department of Nuclear Medicine, Cerrahpasa Medical Faculty, Istanbul University, Fatih, Istanbul, Turkey,
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Uslu L, Sen F, Sager S, Halaç M. Extensive peritoneal and pleural lymphomatosis in a patient with Burkitt lymphoma revealed with 18F-FDG PET/CT. Nuklearmedizin 2013; 52:N56-N57. [PMID: 24085460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 03/25/2013] [Indexed: 06/02/2023]
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Abstract
Periodic cellular processes and especially circadian rhythms governed by the oscillating expression of a set of genes based on feedback regulation by their products have become an important issue in biology and medicine. The central circadian clock is an autonomous biochemical oscillator with a period close to 24 h. Research in chronobiology demonstrated that light stimuli can be used to delay or advance the phase of the oscillator, allowing it to influence the underlying physiological processes. Phase shifting and restoration of altered rhythms can generally be viewed as open-loop control problems that may be used for therapeutic purposes in diseases. A circadian oscillator model of the central clock mechanism is studied for the fruit fly Drosophila and show how model-based mixed-integer optimal control allows for the design of chronomodulated pulse-stimuli schemes achieving circadian rhythm restoration in mutants and optimal phase synchronisation between the clock and its environment.
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Affiliation(s)
- O S Shaik
- Interdisciplinary Center for Scientific Computing, University of Heidelberg, Germany
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Sweeney LM, Thrall KD, Poet TS, Corley RA, Weber TJ, Locey BJ, Clarkson J, Sager S, Gargas ML. Physiologically based pharmacokinetic modeling of 1,4-Dioxane in rats, mice, and humans. Toxicol Sci 2007; 101:32-50. [PMID: 17897969 DOI: 10.1093/toxsci/kfm251] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
1,4-Dioxane (CAS No. 123-91-1) is used primarily as a solvent or as a solvent stabilizer. It can cause lung, liver, and kidney damage at sufficiently high exposure levels. Two physiologically based pharmacokinetic (PBPK) models of 1,4-dioxane and its major metabolite, hydroxyethoxyacetic acid (HEAA), were published in 1990. These models have uncertainties and deficiencies that could be addressed and the model strengthened for use in a contemporary cancer risk assessment for 1,4-dioxane. Studies were performed to fill data gaps and reduce uncertainties pertaining to the pharmacokinetics of 1,4-dioxane and HEAA in rats, mice, and humans. Three types of studies were performed: partition coefficient measurements, blood time course in mice, and in vitro pharmacokinetics using rat, mouse, and human hepatocytes. Updated PBPK models were developed based on these new data and previously available data. The optimized rate of metabolism for the mouse was significantly higher than the value previously estimated. The optimized rat kinetic parameters were similar to those in the 1990 models. Only two human studies were identified. Model predictions were consistent with one study, but did not fit the second as well. In addition, a rat nasal exposure was completed. The results confirmed water directly contacts rat nasal tissues during drinking water under bioassay conditions. Consistent with previous PBPK models, nasal tissues were not specifically included in the model. Use of these models will reduce the uncertainty in future 1,4-dioxane risk assessments.
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Lebiedz D, Sager S, Bock HG, Lebiedz P. Annihilation of limit-cycle oscillations by identification of critical perturbing stimuli via mixed-integer optimal control. Phys Rev Lett 2005; 95:108303. [PMID: 16196975 DOI: 10.1103/physrevlett.95.108303] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2005] [Indexed: 05/04/2023]
Abstract
We present a novel model-based mixed-integer optimal control method to automatically identify the strength and timing of critical external stimuli leading to the transient annihilation of limit-cycle oscillators. Biochemical oscillators of this type play a central role in regulating cellular rhythms. Their specific manipulation is a promising perspective to control biological functions by drugs and tailored treatment strategies. We demonstrate our new optimal control approach in an application to a biochemical model for oscillatory calcium signal transduction.
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Affiliation(s)
- D Lebiedz
- Interdisciplinary Center for Scientific Computing, Heidelberg, Germany.
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Brandt-Pollmann U, Lebiedz D, Diehl M, Sager S, Schlöder J. Real-time nonlinear feedback control of pattern formation in (bio)chemical reaction-diffusion processes: a model study. Chaos 2005; 15:33901. [PMID: 16252992 DOI: 10.1063/1.1955387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Theoretical and experimental studies related to manipulation of pattern formation in self-organizing reaction-diffusion processes by appropriate control stimuli become increasingly important both in chemical engineering and cellular biochemistry. In a model study, we demonstrate here exemplarily the application of an efficient nonlinear model predictive control (NMPC) algorithm to real-time optimal feedback control of pattern formation in a bacterial chemotaxis system modeled by nonlinear partial differential equations. The corresponding drift-diffusion model type is representative for many (bio)chemical systems involving nonlinear reaction dynamics and nonlinear diffusion. We show how the computed optimal feedback control strategy exploits the system inherent physical property of wave propagation to achieve desired control aims. We discuss various applications of our approach to optimal control of spatiotemporal dynamics.
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Affiliation(s)
- U Brandt-Pollmann
- Interdisciplinary Center for Scientific Computing, Im Neuenheimer Feld 368, D-69120 Heidelberg, Germany
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Abstract
We describe an infant who had methemoglobinemia related to acidosis, probably on the basis of renal tubular acidosis. Methemoglobinemia may indicate the presence of a clinically significant underlying disorder.
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Affiliation(s)
- S Sager
- Gwynne Hazen Cherry Memorial Laboratory, Department of Pediatrics, University of California at Los Angeles School of Medicine, 90024
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Sager S, Ettenger RB. Kidney transplantation in children. Semin Pediatr Surg 1993; 2:235-47. [PMID: 8062044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Over the past decade, the success rate of pediatric kidney transplantation has dramatically increased, based on improvements in histocompatibility testing, immunosuppressive management, and diagnosis and treatment of rejection. The 1-year graft survival rate now approaches 90%. The optimal age for recipients as well as for donor organs is greater than six years. Recurrence of primary disease in the graft accounts for approximately 5% graft loss in children. Sequential immunosuppressive protocols have been particularly successful in children, and maintenance immunosuppression routinely includes corticosteroids, azathioprine, and cyclosporin A. Posttransplantation complications include rejection, infection, hypertension, growth retardation, and noncompliance.
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Affiliation(s)
- S Sager
- Department of Pediatrics, UCLA School of Medicine
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Sager S, Virella G, Chen WY, Fudenberg HH. Isolation and characterization of an outer membrane protein of Salmonella paratyphi B: a mitogen and polyclonal activator of human B lymphocytes. Immunol Suppl 1984; 52:67-78. [PMID: 6370841 PMCID: PMC1454589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Salmonella paratyphi B (S. paratyphi B) has been previously characterized as a human T-independent polyclonal B cell activator. To define further the nature of the bacterial structure responsible for these properties, we studied the effects of autoclaving and enzyme treatment of S. paratyphi B on its stimulatory capacity. We found that both autoclaving and papain treatment decreased the ability of S. paratyphi B to induce B cell activation, while trypsin treatment did not affect this capacity. Neither type of treatment affected the binding of S. paratyphi B to lymphocytes, suggesting that binding and B cell stimulation are mediated by different structures. The observation that B cell stimulation was significantly reduced by papain treatment led us to attempt to purify membrane proteins so that we could investigate whether they shared the stimulating capacity of S. paratyphi B. A water-insoluble, 43-45,000 mol. wt. protein, rich in aspartic acid, glutamine, glycine, alanine and leucine, similar in mol. wt. and physicochemical chemical properties to the porins of other gram negative bacteria, was isolated and designated as outer membrane protein (OMP). This protein was equally efficient to S. paratyphi B in inducing T-independent B cell activation. By performing time-course studies of [3H]-thymidine incorporation we observed a burst of mitogenic activity after stimulation of PBL or purified B cells with both S. paratyphi B and OMP peaking at 48-96 hr of culture (compared to 96-120 hr for the PWM proliferation peak), and with a magnitude of roughly 10% of that observed after PWM stimulation. Given the fact that the proportion of B lymphocytes in PBL is 4-12%, it appears likely that the proliferation burst seen with S. paratyphi B and OMP corresponds to a mitogenic effect mainly restricted to the B cell population.
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Tsang KY, Fudenberg HH, Sun DC, Pai GS, Bishop LR, Sager S. Cultivation of human osteosarcoma cell lines in serum-free hormone supplemented medium. In Vitro 1983; 19:515-21. [PMID: 6575958 DOI: 10.1007/bf02619599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Two human osteosarcoma cell lines (TE-85, LM-1) were adapted to grow in serum-free hydrocortisone supplemented medium. Human osteosarcoma associated antigens were detected both on the cell membrane as well as in the concentrated culture medium. TE-85 cells produced bone specific alkaline phosphatase and LM-1 cells produced both bone specific and placental-like alkaline phosphatases when cultured in this medium. Successful proliferation of human osteosarcoma cell lines in serum-free medium is valuable in human osteosarcoma research.
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Abstract
Mitogenesis and polyclonal immunoglobulin production in peripheral blood lymphocyte cultures activated with Formalin-fixed or autoclaved protein A-containing Staphylococcus aureus were studied. Direct evidence for a dissociation between cell proliferation and polyclonal immunoglobulin production was found, in that S. aureus was not mitogenic after being autoclaved but retained the ability to stimulate B cells to produce immunoglobulin. Trypsin-treated S. aureus lost its binding site for immunoglobulin G, but its mitogenicity was not altered; thus, the protein A binding site for immunoglobulin G on the bacterial cell wall is not required for the stimulation of lymphocyte proliferation. Our data also show a dissociation between cell proliferation and polyclonal immunoglobulin production induced by protein A coupled to Sepharose CL-4B. These results suggest the presence of three distinct active sites on the protein A molecule: one that binds immunoglobulin G molecules, one that stimulates cell proliferation, and one that stimulates polyclonal immunoglobulin production.
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