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Kapulla R, Paranjape S, Fehlmann M, Suter S, Doll U, Paladino D. The effects of activated cooler power on the transient pressure decay and helium mixing in the PANDA facility. Nuclear Engineering and Technology 2021. [DOI: 10.1016/j.net.2021.12.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Paranjape S, Von Berg K, Vanscoy L, Leonard A, Peeler D, Pan A, Jordon D, Denhard M, Loosen H, Mogayzel P. 78: Using pre-visit planning and electronic health record messaging to improve liver function and annual lab monitoring in the pediatric cystic fibrosis clinic. J Cyst Fibros 2021. [DOI: 10.1016/s1569-1993(21)01503-4] [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: 11/26/2022]
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Miller MJ, Skrzekut A, Kracalik I, Jones JM, Lofy KH, Konkle BA, Haley NR, Duvenhage M, Bonnett T, Holbrook M, Higgs E, Basavaraju SV, Paranjape S. How do I… facilitate a rapid response to a public health emergency requiring plasma collection with a public-private partnership? Transfusion 2021; 61:2814-2824. [PMID: 34510475 DOI: 10.1111/trf.16630] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 06/02/2021] [Revised: 07/27/2021] [Accepted: 07/27/2021] [Indexed: 12/14/2022]
Abstract
In March 2020, there were no treatment options for COVID-19. Passive immune therapy including anti-SARS-CoV-2 hyperimmune globulin (hIVIG) was a logical candidate for COVID-19 therapeutic trials, given past success treating emerging pathogens with endogenous neutralizing antibodies. We established a plasma collection protocol for persons recovered from COVID-19. To speed recruitment in the first U.S. hotspot, Seattle, Washington, federal and state public health agencies collaborated with Bloodworks Northwest to collect convalescent plasma (CP) for manufacturing hIVIG. During March-December 2020, we identified and recruited prospective CP donors via letters to persons recovered from COVID-19 with laboratory-confirmed SARS-CoV-2 infection. Prospective donors were pre-screened and administered a medical history survey. Anti-SARS-CoV-2 neutralizing antibody (NAb) titers were classified as qualifying (≥1:80) or non-qualifying (<1:80) for enrollment based on a live virus neutralization assay. Generalized estimating equations were used to identify characteristics of donors associated with qualifying versus nonqualifying NAb titers. Overall, 21,359 letters resulted in 3207 inquiries, 2159 prescreenings with laboratory-confirmed SARS-CoV-2 infection, and 573 donors (27% of all pre-screenings with confirmed infection) who provided a screening plasma donation. Of 573 donors screened, 254 (44%) provided plasma with qualifying NAb titers, resulting in 1284 units for hIVIG manufacture. In a multivariable model, after adjusting for other factors, time (60 days) from COVID-19 symptom onset to screening was associated with lower odds of qualifying NAb (adjusted odds ratio = 0.67, 95% CI: 0.48-0.94). The collaboration facilitated a rapid response to develop and provide hIVIG for clinical trials and CP for transfusion. Only 1 in 12 donor inquiries resulted in a qualifying plasma donation. Challenges included recruitment and the relatively low percentage of persons with high NAb titers and limited screening capacity. This resource-intensive collaboration may not be scalable but informs preparedness and response strategies for plasma collection in future epidemics. Operational readiness plans with templates for screening, consent, and data collection forms are recommended.
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Affiliation(s)
- Maureen J Miller
- Epidemic Intelligence Service, U.S. Centers for Disease Control and Prevention, Atlanta, Georgia, USA.,COVID-19 Response Team, U.S. Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | | | - Ian Kracalik
- Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Jefferson M Jones
- COVID-19 Response Team, U.S. Centers for Disease Control and Prevention, Atlanta, Georgia, USA.,Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Kathryn H Lofy
- Washington State Department of Health, Tumwater, Washington, USA
| | | | | | - Michael Duvenhage
- Division of Clinical Research, National Institute of Allergy and Infectious Diseases, Rockville, Maryland, USA
| | - Tyler Bonnett
- Clinical Monitoring Research Program Directorate, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Michael Holbrook
- Division of Clinical Research, Integrated Research Facility, NIAID, Rockville, Maryland, USA
| | | | - Sridhar V Basavaraju
- Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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Voolstra CR, Valenzuela JJ, Turkarslan S, Cárdenas A, Hume BCC, Perna G, Buitrago-López C, Rowe K, Orellana MV, Baliga NS, Paranjape S, Banc-Prandi G, Bellworthy J, Fine M, Frias-Torres S, Barshis DJ. Contrasting heat stress response patterns of coral holobionts across the Red Sea suggest distinct mechanisms of thermal tolerance. Mol Ecol 2021; 30:4466-4480. [PMID: 34342082 DOI: 10.1111/mec.16064] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 06/04/2021] [Accepted: 06/30/2021] [Indexed: 12/18/2022]
Abstract
Corals from the northern Red Sea, in particular the Gulf of Aqaba (GoA), have exceptionally high bleaching thresholds approaching >5℃ above their maximum monthly mean (MMM) temperatures. These elevated thresholds are thought to be due to historical selection, as corals passed through the warmer Southern Red Sea during recolonization from the Arabian Sea. To test this hypothesis, we determined thermal tolerance thresholds of GoA versus central Red Sea (CRS) Stylophora pistillata corals using multi-temperature acute thermal stress assays to determine thermal thresholds. Relative thermal thresholds of GoA and CRS corals were indeed similar and exceptionally high (~7℃ above MMM). However, absolute thermal thresholds of CRS corals were on average 3℃ above those of GoA corals. To explore the molecular underpinnings, we determined gene expression and microbiome response of the coral holobiont. Transcriptomic responses differed markedly, with a strong response to the thermal stress in GoA corals and their symbiotic algae versus a remarkably muted response in CRS colonies. Concomitant to this, coral and algal genes showed temperature-induced expression in GoA corals, while exhibiting fixed high expression (front-loading) in CRS corals. Bacterial community composition of GoA corals changed dramatically under heat stress, whereas CRS corals displayed stable assemblages. We interpret the response of GoA corals as that of a resilient population approaching a tipping point in contrast to a pattern of consistently elevated thermal resistance in CRS corals that cannot further attune. Such response differences suggest distinct thermal tolerance mechanisms that may affect the response of coral populations to ocean warming.
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Affiliation(s)
| | | | | | - Anny Cárdenas
- Department of Biology, University of Konstanz, Konstanz, Germany
| | | | - Gabriela Perna
- Department of Biology, University of Konstanz, Konstanz, Germany
| | | | - Katherine Rowe
- School of Science, The University of Waikato, Hamilton, New Zealand
| | - Monica V Orellana
- Institute for Systems Biology, Seattle, USA.,Polar Science Center, University of Washington, Seattle, USA
| | - Nitin S Baliga
- Institute for Systems Biology, Seattle, USA.,Departments of Biology and Microbiology, University of Washington, Seattle, USA.,Molecular and Cellular Biology Program, University of Washington, Seattle, USA.,Lawrence Berkeley National Laboratory, Berkeley, USA
| | | | - Guilhem Banc-Prandi
- The Interuniversity Institute for Marine Sciences (IUI), Eilat, Israel.,The Goodman Faculty of Life Sciences, Bar Ilan University, Ramat-Gan, Israel
| | - Jessica Bellworthy
- The Interuniversity Institute for Marine Sciences (IUI), Eilat, Israel.,The Goodman Faculty of Life Sciences, Bar Ilan University, Ramat-Gan, Israel
| | - Maoz Fine
- The Interuniversity Institute for Marine Sciences (IUI), Eilat, Israel.,The Goodman Faculty of Life Sciences, Bar Ilan University, Ramat-Gan, Israel
| | | | - Daniel J Barshis
- Department of Biological Sciences, Old Dominion University, Norfolk, USA
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Dailey GE, Reid T, White J, Chao J, Zhou FL, Paranjape S, Berhanu P. Insulin glargin 300 E/ml (Gla-300) zeigte eine verbesserte glykämische Kontrolle sowie ein niedrigeres Hypoglykämierisiko bei Typ-2-Diabetespatienten mit Reduktion der bisherigen oralen Antidiabetestherapie (OAD). DIABETOL STOFFWECHS 2018. [DOI: 10.1055/s-0038-1641928] [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: 10/28/2022]
Affiliation(s)
- GE Dailey
- Scripps Whittier Diabetes Institute, San Diego, CA, United States
| | - T Reid
- Mercy Diabetes Center, Janesville, WI, United States
| | - J White
- Washington State University School of Pharmacy, Washington, WA, United States
| | - J Chao
- Xinyi, Inc., Bridgewater, NJ, United States
| | - FL Zhou
- Sanofi US, Inc., Bridgewater, NJ, United States
| | - S Paranjape
- Sanofi US, Inc., Bridgewater, NJ, United States
| | - P Berhanu
- Sanofi US, Inc., Bridgewater, NJ, United States
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Yang X, Schlegel J, Liu Y, Paranjape S, Hibiki T, Ishii M, Bajorek S, Ireland A. Prediction of interfacial area transport in a scaled 8×8 BWR rod bundle. Nuclear Engineering and Design 2016. [DOI: 10.1016/j.nucengdes.2016.10.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Wertz MS, Kyriss T, Paranjape S, Glantz SA. The toxic effects of cigarette additives. Philip Morris' project mix reconsidered: an analysis of documents released through litigation. PLoS Med 2011; 8:e1001145. [PMID: 22205885 PMCID: PMC3243707 DOI: 10.1371/journal.pmed.1001145] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Accepted: 11/07/2011] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND In 2009, the promulgation of US Food and Drug Administration (FDA) tobacco regulation focused attention on cigarette flavor additives. The tobacco industry had prepared for this eventuality by initiating a research program focusing on additive toxicity. The objective of this study was to analyze Philip Morris' Project MIX as a case study of tobacco industry scientific research being positioned strategically to prevent anticipated tobacco control regulations. METHODS AND FINDINGS We analyzed previously secret tobacco industry documents to identify internal strategies for research on cigarette additives and reanalyzed tobacco industry peer-reviewed published results of this research. We focused on the key group of studies conducted by Phillip Morris in a coordinated effort known as "Project MIX." Documents showed that Project MIX subsumed the study of various combinations of 333 cigarette additives. In addition to multiple internal reports, this work also led to four peer-reviewed publications (published in 2001). These papers concluded that there was no evidence of substantial toxicity attributable to the cigarette additives studied. Internal documents revealed post hoc changes in analytical protocols after initial statistical findings indicated an additive-associated increase in cigarette toxicity as well as increased total particulate matter (TPM) concentrations in additive-modified cigarette smoke. By expressing the data adjusted by TPM concentration, the published papers obscured this underlying toxicity and particulate increase. The animal toxicology results were based on a small number of rats in each experiment, raising the possibility that the failure to detect statistically significant changes in the end points was due to underpowering the experiments rather than lack of a real effect. CONCLUSION The case study of Project MIX shows tobacco industry scientific research on the use of cigarette additives cannot be taken at face value. The results demonstrate that toxins in cigarette smoke increase substantially when additives are put in cigarettes, including the level of TPM. In particular, regulatory authorities, including the FDA and similar agencies elsewhere, could use the Project MIX data to eliminate the use of these 333 additives (including menthol) from cigarettes.
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Affiliation(s)
- Marcia S. Wertz
- Center for Tobacco Control Research and Education, University of California San Francisco, San Francisco, California, United States of America
- Department of Social and Behavioral Sciences, School of Nursing, University of California San Francisco San Francisco, California, United States of America
| | - Thomas Kyriss
- Thoracic Surgery, Schillerhoehe Hospital, Gerlingen, Germany
| | - Suman Paranjape
- Center for Tobacco Control Research and Education, University of California San Francisco, San Francisco, California, United States of America
| | - Stanton A. Glantz
- Center for Tobacco Control Research and Education, University of California San Francisco, San Francisco, California, United States of America
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
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Schlegel J, Sawant P, Paranjape S, Ozar B, Hibiki T, Ishii M. Void fraction and flow regime in adiabatic upward two-phase flow in large diameter vertical pipes. Nuclear Engineering and Design 2009. [DOI: 10.1016/j.nucengdes.2009.08.004] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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9
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Faro A, Mallory GB, Visner GA, Elidemir O, Mogayzel PJ, Danziger-Isakov L, Michaels M, Sweet S, Michelson P, Paranjape S, Conrad C, Waltz DA. American Society of Transplantation executive summary on pediatric lung transplantation. Am J Transplant 2007; 7:285-92. [PMID: 17109726 DOI: 10.1111/j.1600-6143.2006.01612.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [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: 01/25/2023]
Abstract
Lung transplantation in children poses distinctly different challenges from those seen in the adult population. This consensus statement reviews the experience in the field of pediatric lung transplantation and highlights areas that deserve further investigation.
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Affiliation(s)
- A Faro
- Department of Pediatrics, Washington University, St. Louis, MO, USA.
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Prabhu RR, Kulkarni MJ, Parasharami VA, Santhakumari B, Paranjape S. An attempt at taxonomical characterization of some Rhizobial species by intact cell MALDI mass spectrometry. World J Microbiol Biotechnol 2007. [DOI: 10.1007/s11274-006-9207-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Arankalle VA, Paranjape S, Emerson SU, Purcell RH, Walimbe AM. Phylogenetic analysis of hepatitis E virus isolates from India (1976-1993). J Gen Virol 1999; 80 ( Pt 7):1691-1700. [PMID: 10423137 DOI: 10.1099/0022-1317-80-7-1691] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Seventeen Indian hepatitis E virus (HEV) isolates, representing epidemic and sporadic hepatitis E cases during 1976-1991, were sequenced in the RNA polymerase (RNAP) region. Five isolates were also sequenced in the non-structural hypervariable region of open reading frame 1. Open reading frames 2 and 3 were sequenced only for the prototype isolate. On the basis of the comparison of all the available sequences of the conserved RNAP region, the HEV isolates were divided into three genotypes, differing from each other by >15%. Genotype I included African and Asian isolates, whereas II and III were represented by Mexican and US isolates, respectively. Genotype I was further divided into four sub-genotypes. The majority of the Indian isolates (15/20), along with the Burmese and Nepali isolates, belonged to genotype IA. Genotype IB included HEV isolates from China, Pakistan and the former USSR and 2/20 Indian isolates, which represented the oldest (1976) HEV sequenced so far. Genotype IC included both the African isolates, whereas 3/20 Indian isolates formed genotype ID. Nucleotide sequence analysis of other regions of the HEV genome also placed isolates in the same genotypes. Both the Indian cities experiencing second HEV epidemics, after intervals of 8 and 10 years, showed shifts in the sub-genotypes found; from IB (Ahm-76) to IA (Ahm-84) and from IA (Kol-81) to ID (Kol-91). However, no major shift in the genotypes was noted. Overall, HEV genotypes appear to be segregated geographically.
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Shouche YS, Patole MS, Pant U, Paranjape S, Banerjee K. Authentication of two cell lines developed from the larval and pupal ovaries of Spodoptera litura by rRNA based methods. In Vitro Cell Dev Biol Anim 1999; 35:244-5. [PMID: 10475268 DOI: 10.1007/s11626-999-0066-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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13
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Dimitrijevich SD, Paranjape S, Wilson JR, Gracy RW, Mills JG. Effect of hyperbaric oxygen on human skin cells in culture and in human dermal and skin equivalents. Wound Repair Regen 1999; 7:53-64. [PMID: 10231506 DOI: 10.1046/j.1524-475x.1999.00053.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A critical stage of cutaneous wound healing is the development and maturation of the epidermis. In the aged, and in certain pathologies, this repair process is compromised due to a variety of deficiencies, one of which is tissue oxygenation. Several phases of wound healing are dependent on adequate tissue oxygen levels, and hyperbaric oxygenation has been shown to transiently elevate these levels. The use of human cell monolayers, dermal equivalents and human skin equivalents provide excellent opportunities for studying wound healing using in vivo relevant models. The goal of this study was to examine the effect of hyperbaric oxygen on cell proliferation, differentiation, and matrix biosynthesis in monolayer cultures and epidermopoiesis in the developing skin equivalent. Normal human dermal fibroblasts, keratinocytes and melanocytes, dermal equivalents and skin equivalents were exposed to hyperbaric oxygen at pressures up to three atmospheres, for up to 10 consecutive daily treatments lasting 90 minutes each. Increase in fibroblast proliferation (cf., 30% at 1 atmosphere after 10 days treatment), was observed without a significant effect on proliferation of normal human melanocytes and glycosaminoglycan synthesis. Stimulation of collagen synthesis after two days of treatment was only significant at 1 atmosphere (about 20% increase) but this differential was not observed after 5 days of treatment. Hyperbaric oxygenation above 2 atmospheres, inhibited proliferation of fibroblasts and keratinocytes in cell monolayer cultures (e.g., a 10 day treatment at 3 atmospheres appeared cytostatic to keratinocytes). In contrast, hyperbaric treatment up to 3 atmospheres dramatically enhanced keratinocyte differentiation, and epidermopoiesis in the complete human skin equivalent. These results support the importance of hyperbaric oxygen therapy in wound healing, and should provide an insight into oxygen utilization during repair of peripheral human tissue. The results also show the utility of the human skin equivalent as a model for evaluation of parameters involved in wound healing.
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Affiliation(s)
- S D Dimitrijevich
- Department of Molecular Biology and Immunology, Wound Healing Research Institute, University of North Texas Health Science Center, Fort Worth,Texas 76107, USA
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Hill JS, O K, Wang X, Paranjape S, Dimitrijevich D, Lacko AG, Pritchard PH. Expression and characterization of recombinant human lecithin:cholesterol acyltransferase. J Lipid Res 1993; 34:1245-51. [PMID: 8371071] [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: 01/30/2023] Open
Abstract
We have established a baby hamster kidney (BHK) cell line that constitutively expresses significant quantities of human recombinant lecithin:cholesterol acyltransferase (rLCAT). LCAT cDNA was cloned into a mammalian expression vector containing the metallothionein promoter and the dihydrofolate reductase gene. After transfection, the BHK cells were treated with 500 microM methotrexate for 2 weeks to select the successfully transfected cells. Surviving colonies were subcloned and high level secretors were identified by measurement of LCAT activity and mass in the culture medium. The attachment of transfected cells to microcarrier beads enabled the efficient production of large quantities of rLCAT in a serum-free medium. After a single-step chromatography procedure, the rLCAT was purified to homogeneity with yields exceeding 1 mg of rLCAT per 100 ml of culture medium. The molecular weight of rLCAT (approximately 66,000) was identical to that of purified human plasma LCAT on SDS polyacrylamide electrophoresis. The rLCAT was activated by apolipoprotein A-I and had an average specific activity that was similar to purified plasma LCAT. After selective deglycosylation with either neuraminidase or N-glycanase, rLCAT and plasma LCAT had identical molecular weights. The simplification of the production and purification of rLCAT reported here will enable a more in depth analysis of the structure and function of this enzyme.
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Affiliation(s)
- J S Hill
- Department of Pathology, University of British Columbia, Vancouver, Canada
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Harootunian AT, Kao JP, Paranjape S, Adams SR, Potter BV, Tsien RY. Cytosolic Ca2+ oscillations in REF52 fibroblasts: Ca(2+)-stimulated IP3 production or voltage-dependent Ca2+ channels as key positive feedback elements. Cell Calcium 1991; 12:153-64. [PMID: 1647875 DOI: 10.1016/0143-4160(91)90017-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Oscillations in cytosolic free calcium concentrations ([Ca2+]i) can be elicited in REF52 fibroblasts by three different modes of stimulation. We have previously demonstrated that [Ca2+]i oscillations result when these cells are simultaneously depolarized and stimulated with a hormone linked to phosphoinositide breakdown. Further evidence is now presented that such oscillations are linked to fluctuations in the concentration of IP3 and the Ca2+ content of an IP3-sensitive Ca2+ store. [Ca2+]i oscillations can also be generated in REF52 cells either by direct stimulation of G-proteins with GTP gamma S or AlF4- or by destabilizing the membrane potential and opening voltage-dependent calcium channels. This report compares the different types of oscillations and their mechanisms.
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Affiliation(s)
- A T Harootunian
- Howard Hughes Medical Institute, University of California San Diego, La Jolla
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Abstract
A wide variety of nonexcitable cells generate repetitive transient increases in cytosolic calcium ion concentration ([Ca2+]i) when stimulated with agonists that engage the phosphoinositide signalling pathway. Current theories regarding the mechanisms of oscillation disagree on whether Ca2+ inhibits or stimulates its own release from internal stores and whether inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DG) also undergo oscillations linked to the Ca2+ spikes. In this study, Ca2+ was found to stimulate its own release in REF52 fibroblasts primed by mitogens plus depolarization. However, unlike Ca2+ release in muscle and nerve cells, this amplification was insensitive to caffeine or ryanodine and required hormone receptor occupancy and functional IP3 receptors. Oscillations in [Ca2+]i were accompanied by oscillations in IP3 concentration but did not require functional protein kinase C. Therefore, the dominant feedback mechanism in this cell type appears to be Ca2+ stimulation of phospholipase C once this enzyme has been activated by hormone receptors.
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Affiliation(s)
- A T Harootunian
- Howard Hughes Medical Institute M-047, University of California San Diego, La Jolla 92093-0647
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Shenoy BC, Paranjape S, Murtif VL, Kumar GK, Samols D, Wood HG. Effect of mutations at Met-88 and Met-90 on the biotination of Lys-89 of the apo 1.3S subunit of transcarboxylase. FASEB J 1988; 2:2505-11. [PMID: 3131174 DOI: 10.1096/fasebj.2.9.3131174] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The apo 1.3S subunit of transcarboxylase contains the sequence Ala-87-Met-88-Lys-89-Met-90, and it is Lys-89 that is biotinated. This sequence is highly conserved in all the biotin enzymes that have been sequenced (with the exception of acetyl-CoA carboxylase from chicken liver, which has Val in place of Ala). The role of Met-88 and Met-90 in specifying Lys-89 for biotination by synthetase was examined by site-directed mutagenesis. Genes of the 1.3S subunit coding for Thr-88, Leu-88, or Leu-90 were generated by oligonucleotide-directed in vitro mutagenesis and expressed in Escherichia coli. The mutated apo 1.3S subunits were isolated and the biotination by homogeneous synthetase from Propionibacterium shermanii was compared with that of the apo wild-type subunit. The Vmax for the apo mutants was the same as that for the apo wild type, but when Leu was substituted for Met-88 or Met-90, the Km for the mutant was lower than that of the wild-type or mutant Thr-88. The activity of the synthetase of E. coli was determined by an in vivo assay. During the early log phase of growth, a smaller portion of mutants Thr-88 and Leu-90 was biotinated than with the wild-type or mutant Leu-88. When the cultures progressed to stationary phase, mutants and the wild type were biotinated to the same extent. The overall results show that Met-88 and Met-90 are not required for biotination of the apo 1.3S subunit by the synthetases.
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Affiliation(s)
- B C Shenoy
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
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