1
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Voss L, Huaman J, Pacioni C, Tolpinrud A, Helbig K, Carvalho TG, Firestone SM. Seroprevalence of Coxiella burnetii antibodies in wild deer populations in eastern Australia. Aust Vet J 2023; 101:106-114. [PMID: 36544232 DOI: 10.1111/avj.13223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 04/06/2022] [Revised: 11/18/2022] [Accepted: 11/24/2022] [Indexed: 12/24/2022]
Abstract
Coxiella burnetii causes significant reproduction losses in livestock and the disease Q fever in humans. Transmission of C. burnetii is facilitated by the stability of the bacterium in the environment and the susceptibility of a variety of host species to infection. Consequently, inter-species transmission occurs frequently through either direct or indirect contact. Wildlife may represent reservoirs of C. burnetii and could therefore be a source of infection for domestic animals. Understanding the prevalence of C. burnetii infections at the wildlife-livestock interface is important for disease control. This study aimed to investigate the extent of C. burnetii exposure in wild deer in eastern Australia. Serum samples were obtained from 413 wild deer from seven regions in four eastern Australian states from 2017 to 2020. Antibodies were detected using a commercial Q fever antibody kit validated for ruminants. Seroprevalence of C. burnetii antibodies in deer was determined and true prevalence estimated, for each region. The overall seroprevalence of C. burnetii antibodies in wild deer was 3.4% (14 seropositive of 413 deer sampled) with true prevalence estimated to be 4.3% (95% credible interval: 0.6%, 10.9%). Seropositive deer were identified only in Queensland (7/108 seropositive) and northern New South Wales (7/120 seropositive). This geospatial distribution is consistent with seropositivity in other animal species and indicative of the level of C. burnetii in the environment. The low seroprevalence suggests that wild deer are unlikely to be a major reservoir species for C. burnetii in eastern Australia but may still be implicated in inter-species transmission cycles.
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Affiliation(s)
- L Voss
- Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Parkville, Victoria, Australia
| | - J Huaman
- Department of Microbiology, Anatomy, Physiology and Pharmacology, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Victoria, Australia
| | - C Pacioni
- Department of Environment, Land, Water and Planning, Arthur Rylah Institute for Environmental Research, Heidelberg, Victoria, Australia.,Environmental and Conservation Sciences, Murdoch University, Murdoch, Western Australia, Australia
| | - A Tolpinrud
- Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Parkville, Victoria, Australia
| | - K Helbig
- Department of Microbiology, Anatomy, Physiology and Pharmacology, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Victoria, Australia
| | - T G Carvalho
- Department of Microbiology, Anatomy, Physiology and Pharmacology, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Victoria, Australia
| | - S M Firestone
- Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Parkville, Victoria, Australia
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2
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Pacheco S, Donadio M, O'Connor J, De Miguel V, Beltran P, Huaman J, Dioca M, Bragagnoli A, Weschenfelder R, Riechelmann R. 1120P The prognostic and predictive roles of Ki67 and functional imaging tests in patients (pts) with metastatic pheochromocytoma or paraganglioma (mPPGL) treated with chemotherapy. Ann Oncol 2021. [DOI: 10.1016/j.annonc.2021.08.202] [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: 11/30/2022] Open
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3
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Huaman J, Ogunwobi OO. Circulating Tumor Cell Migration Requires Fibronectin Acting through Integrin B1 or SLUG. Cells 2020; 9:cells9071594. [PMID: 32630254 PMCID: PMC7408126 DOI: 10.3390/cells9071594] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 06/27/2020] [Accepted: 06/30/2020] [Indexed: 01/16/2023] Open
Abstract
Fibronectin (FN1) is an extracellular matrix protein gaining increasing attention for its multifaceted roles in cancer progression. Using our recently established circulating tumor cell (CTC) lines, we had demonstrated increased FN1 expression and enhanced migration in CTC lines, in comparison to primary tumor cell lines. Whether increased FN1 expression is directly required for CTC migration, and the specific role of FN1’s regulation of integrin B1 (ITGB1) and SLUG (SNAI2) in CTC migration remains unclear. Here, for the first time, we report that the knockdown of FN1, ITGB1, or SLUG expression in CTCs leads to a significant decrease in CTC migration. Knocking down two or all three of these proteins simultaneously did not further inhibit migration. We observed a corresponding increase in CTC migration when recombinant FN1 was added to CTCs. This effect was significantly impeded by prior knockdown of ITGB1 or SLUG. Using knock down experiments and western blotting analysis, we confirmed FN1’s regulation of ITGB1 and SLUG to occur via two separate, independent pathways. Consequently, we can conclude that FN1-dependent enhanced migration of CTCs requires downstream signaling through either ITGB1 or SLUG and that FN1 regulation of ITGB1 and SLUG may have important implications for cancer progression and metastasis.
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Affiliation(s)
- Jeannette Huaman
- Department of Biological Sciences, Hunter College of The City University of New York, New York, NY 10065, USA;
- Department of Biology, The Graduate Center of The City University of New York, New York, NY 10016, USA
| | - Olorunseun O. Ogunwobi
- Department of Biological Sciences, Hunter College of The City University of New York, New York, NY 10065, USA;
- Department of Biology, The Graduate Center of The City University of New York, New York, NY 10016, USA
- Department of Medicine, Weill Cornell Medicine, New York, NY 10065, USA
- Correspondence:
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4
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Pal G, Huaman J, Levine F, Orunmuyi A, Olapade-Olaopa EO, Ogunwobi OO. Abstract B074: The long noncoding RNA from PVT1 exon 9 is overexpressed in prostate cancer in Black males and induces malignant transformation, invasiveness, and castration-resistance in prostate epithelial cells. Cancer Epidemiol Biomarkers Prev 2020. [DOI: 10.1158/1538-7755.disp19-b074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Abstract
Prostate cancer (PCa) is the most common non-skin cancer and the second leading cause of cancer-related death for men in the United States. PCa is the greatest source of cancer-related mortality in males of African ancestry. One of the most important susceptibility loci for cancer is the 8q24 human chromosomal region. The non-protein coding gene locus plasmacytoma variant translocation 1 (PVT1) is located at 8q24 and is dysregulated in different cancers. PVT1 gives rise to several alternatively spliced transcripts and microRNAs. There are at least twelve exons of PVT1, which make separate transcripts, and likely have different functions. The transcript from PVT1 exon 9 is significantly overexpressed in PCa tissues in comparison to normal prostate tissues obtained from Black males. Both transient and stable overexpression of PVT1 exon 9 induce significantly increased prostate epithelial cell proliferation, migration, and proliferating cell nuclear antigen (PCNA) expression. Notably, implantation into mice of a novel subline of a non-tumorigenic prostate epithelial cell line stably overexpressing PVT1 exon 9 results in the formation of malignant tumors with features characteristic of aggressive PCa. Further, PVT1 exon 9 overexpression significantly induces castration-resistance in prostate epithelial cells. Consequently, PVT1 exon 9 expression is important for PCa initiation and progression and may have potential diagnostic and therapeutic applications in PCa in Black males.
Citation Format: Gargi Pal, Jeannette Huaman, Fayola Levine, Akintunde Orunmuyi, E. Oluwabunmi Olapade-Olaopa, Olorunseun O. Ogunwobi. The long noncoding RNA from PVT1 exon 9 is overexpressed in prostate cancer in Black males and induces malignant transformation, invasiveness, and castration-resistance in prostate epithelial cells [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr B074.
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Affiliation(s)
- Gargi Pal
- 1Hunter College, CUNY, New York, NY, USA,
| | | | | | | | | | - Olorunseun O. Ogunwobi
- 3Hunter College Center for Cancer Health Disparities Research (CCHDR), New York, NY, USA
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5
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Anand P, Filipenko P, Huaman J, Lyudmer M, Hossain M, Santamaria C, Huang K, Ogunwobi OO, Holford M. Selective Inhibition of Liver Cancer Cells Using Venom Peptide. Mar Drugs 2019; 17:E587. [PMID: 31627357 PMCID: PMC6835663 DOI: 10.3390/md17100587] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 10/09/2019] [Accepted: 10/11/2019] [Indexed: 12/18/2022] Open
Abstract
Increasingly cancer is being viewed as a channelopathy because the passage of ions via ion channels and transporters mediate the regulation of tumor cell survival, death, and motility. As a result, a potential targeted therapy for cancer is to use venom peptides that are selective for ion channels and transporters overexpressed in tumor cells. Here we describe the selectivity and mechanism of action of terebrid snail venom peptide, Tv1, for treating the most common type of liver cancer, hepatocellular carcinoma (HCC). Tv1 inhibited the proliferation of murine HCC cells and significantly reduced tumor size in Tv1-treated syngeneic tumor-bearing mice. Tv1's mechanism of action involves binding to overexpressed transient receptor potential (TRP) channels leading to calcium dependent apoptosis resulting from down-regulation of cyclooxygenase-2 (COX-2). Our findings demonstrate the importance of modulating ion channels and the unique potential of venom peptides as tumor specific ligands in the quest for targeted cancer therapies.
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Affiliation(s)
- Prachi Anand
- Department of Chemistry and Biochemistry, Hunter College, Belfer Research Building 413 East 69th Street, New York, NY 10021, USA.
- American Museum of Natural History, Central Park West at 79th St, New York, NY 10024, USA.
- CUNY Graduate Center Chemistry, Biology, Biochemistry Programs, 365 5th Ave, New York, NY 10016, USA.
- Weill Cornell Medicine (Biochemistry Department), 1300 York Avenue, New York, NY 10065, USA.
| | - Petr Filipenko
- Department of Chemistry and Biochemistry, Hunter College, Belfer Research Building 413 East 69th Street, New York, NY 10021, USA.
| | - Jeannette Huaman
- Department of Chemistry and Biochemistry, Hunter College, Belfer Research Building 413 East 69th Street, New York, NY 10021, USA.
- Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA.
- Department of Biological Sciences, Hunter College, 695 Park Avenue, New York, NY 10065, USA.
| | - Michael Lyudmer
- Department of Chemistry and Biochemistry, Hunter College, Belfer Research Building 413 East 69th Street, New York, NY 10021, USA.
| | - Marouf Hossain
- Department of Chemistry and Biochemistry, Hunter College, Belfer Research Building 413 East 69th Street, New York, NY 10021, USA.
| | - Carolina Santamaria
- Department of Chemistry and Biochemistry, Hunter College, Belfer Research Building 413 East 69th Street, New York, NY 10021, USA.
| | - Kelly Huang
- Department of Chemistry and Biochemistry, Hunter College, Belfer Research Building 413 East 69th Street, New York, NY 10021, USA.
| | - Olorunseun O Ogunwobi
- Department of Chemistry and Biochemistry, Hunter College, Belfer Research Building 413 East 69th Street, New York, NY 10021, USA.
- Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA.
- Department of Biological Sciences, Hunter College, 695 Park Avenue, New York, NY 10065, USA.
| | - Mandë Holford
- Department of Chemistry and Biochemistry, Hunter College, Belfer Research Building 413 East 69th Street, New York, NY 10021, USA.
- American Museum of Natural History, Central Park West at 79th St, New York, NY 10024, USA.
- CUNY Graduate Center Chemistry, Biology, Biochemistry Programs, 365 5th Ave, New York, NY 10016, USA.
- Weill Cornell Medicine (Biochemistry Department), 1300 York Avenue, New York, NY 10065, USA.
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6
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Huaman J, Naidoo M, Zang X, Ogunwobi OO. Fibronectin Regulation of Integrin B1 and SLUG in Circulating Tumor Cells. Cells 2019; 8:cells8060618. [PMID: 31226820 PMCID: PMC6627780 DOI: 10.3390/cells8060618] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 06/18/2019] [Accepted: 06/19/2019] [Indexed: 12/12/2022] Open
Abstract
Metastasis is the leading cause of cancer death worldwide. Circulating tumor cells (CTCs) are a critical step in the metastatic cascade and a good tool to study this process. We isolated CTCs from a syngeneic mouse model of hepatocellular carcinoma (HCC) and a human xenograft mouse model of castration-resistant prostate cancer (CRPC). From these models, novel primary tumor and CTC cell lines were established. CTCs exhibited greater migration than primary tumor-derived cells, as well as epithelial-to-mesenchymal transition (EMT), as observed from decreased E-cadherin and increased SLUG and fibronectin expression. Additionally, when fibronectin was knocked down in CTCs, integrin B1 and SLUG were decreased, indicating regulation of these molecules by fibronectin. Investigation of cell surface molecules and secreted cytokines conferring immunomodulatory advantage to CTCs revealed decreased major histocompatibility complex class I (MHCI) expression and decreased endostatin, C-X-C motif chemokine 5 (CXCL5), and proliferin secretion by CTCs. Taken together, these findings indicate that CTCs exhibit distinct characteristics from primary tumor-derived cells. Furthermore, CTCs demonstrate enhanced migration in part through fibronectin regulation of integrin B1 and SLUG. Further study of CTC biology will likely uncover additional important mechanisms of cancer metastasis.
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Affiliation(s)
- Jeannette Huaman
- Department of Biological Sciences, Hunter College of The City University of New York, New York, NY 10065, USA.
- Department of Biology, The Graduate Center of The City University of New York, New York, NY 10016, USA.
| | - Michelle Naidoo
- Department of Biological Sciences, Hunter College of The City University of New York, New York, NY 10065, USA.
- Department of Biology, The Graduate Center of The City University of New York, New York, NY 10016, USA.
| | - Xingxing Zang
- Departments of Microbiology and Immunology, and Medicine (Oncology), Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Olorunseun O Ogunwobi
- Department of Biological Sciences, Hunter College of The City University of New York, New York, NY 10065, USA.
- Department of Biology, The Graduate Center of The City University of New York, New York, NY 10016, USA.
- Department of Medicine, Weill Cornell Medicine, Cornell University, New York, NY 10065, USA.
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7
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Ogunwobi OO, Harricharran T, Huaman J, Galuza A, Odumuwagun O, Tan Y, Ma GX, Nguyen MT. Mechanisms of hepatocellular carcinoma progression. World J Gastroenterol 2019; 25:2279-2293. [PMID: 31148900 PMCID: PMC6529884 DOI: 10.3748/wjg.v25.i19.2279] [Citation(s) in RCA: 124] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 03/27/2019] [Accepted: 04/10/2019] [Indexed: 02/06/2023] Open
Abstract
Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver. It is the second leading cause of cancer-related deaths worldwide, with a very poor prognosis. In the United States, there has been only minimal improvement in the prognosis for HCC patients over the past 15 years. Details of the molecular mechanisms and other mechanisms of HCC progression remain unclear. Consequently, there is an urgent need for better understanding of these mechanisms. HCC is often diagnosed at advanced stages, and most patients will therefore need systemic therapy, with sorafenib being the most common at the present time. However, sorafenib therapy only minimally enhances patient survival. This review provides a summary of some of the known mechanisms that either cause HCC or contribute to its progression. Included in this review are the roles of viral hepatitis, non-viral hepatitis, chronic alcohol intake, genetic predisposition and congenital abnormalities, toxic exposures, and autoimmune diseases of the liver. Well-established molecular mechanisms of HCC progression such as epithelial-mesenchymal transition, tumor-stromal interactions and the tumor microenvironment, cancer stem cells, and senescence bypass are also discussed. Additionally, we discuss the roles of circulating tumor cells, immunomodulation, and neural regulation as potential new mechanisms of HCC progression. A better understanding of these mechanisms could have implications for the development of novel and more effective therapeutic and prognostic strategies, which are critically needed.
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Affiliation(s)
- Olorunseun O Ogunwobi
- Department of Biological Sciences, Hunter College of The City University of New York, New York, NY 10065, United States
- The Graduate Center Departments of Biology and Biochemistry, The City University of New York, New York, NY 10016, United States
- Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medicine, Cornell University, New York, NY 10065, United States
- Hunter College Center for Cancer Health Disparities Research (CCHDR), New York, NY 10065, United States
| | - Trisheena Harricharran
- Department of Biological Sciences, Hunter College of The City University of New York, New York, NY 10065, United States
- The Graduate Center Departments of Biology and Biochemistry, The City University of New York, New York, NY 10016, United States
- Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medicine, Cornell University, New York, NY 10065, United States
- Hunter College Center for Cancer Health Disparities Research (CCHDR), New York, NY 10065, United States
| | - Jeannette Huaman
- Department of Biological Sciences, Hunter College of The City University of New York, New York, NY 10065, United States
- The Graduate Center Departments of Biology and Biochemistry, The City University of New York, New York, NY 10016, United States
- Hunter College Center for Cancer Health Disparities Research (CCHDR), New York, NY 10065, United States
| | - Anna Galuza
- Department of Biological Sciences, Hunter College of The City University of New York, New York, NY 10065, United States
- Hunter College Center for Cancer Health Disparities Research (CCHDR), New York, NY 10065, United States
| | - Oluwatoyin Odumuwagun
- Department of Biological Sciences, Hunter College of The City University of New York, New York, NY 10065, United States
- Hunter College Center for Cancer Health Disparities Research (CCHDR), New York, NY 10065, United States
| | - Yin Tan
- Center for Asian Health, School of Medicine, Temple University, Philadelphia, PA 19140, United States
| | - Grace X Ma
- Center for Asian Health, School of Medicine, Temple University, Philadelphia, PA 19140, United States
| | - Minhhuyen T Nguyen
- Department of Medicine, Fox Chase Cancer Center, Philadelphia, PA 19111, United States
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8
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Aziz EF, Pratap B, Wever-pinzon O, Javed F, Yang YK, Kalal KK, Rao V, Premji R, patel P, Tojino A, Huaman J, Chodakiewitz Y, Herzog E. Abstract P121: Comparison of the Utilization of Evidence-Based Therapies and Clinical Outcomes Between Teaching and Non-Teaching Medical Services After the Implementation of Novel Clinical Pathways for the Management of Cardiac Patients. Circ Cardiovasc Qual Outcomes 2011. [DOI: 10.1161/circoutcomes.4.suppl_1.ap121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE
To compare the utilization of evidence-based (EB) cardiac therapies and clinical outcomes of cardiac care on general medicine inpatient services under teaching and nonteaching services at an academic hospital.
METHODS
In 2005 we implemented the Advanced Cardiac Admission Protocol (ACAP) for all cardiac patients admitted to our hospital. 4170 patients were admitted with ACS or HF were assigned to a resident-staffed teaching service (
n
= 3890) or to a hospitalist-nonteaching service (
n
= 280). We compared utilization of EB therapies, hospital readmission rate at 30 days, length of hospital stay (LOS), and all-cause mortality at 90 days.
RESULTS
The cohort mean age was 63 ± 15 years, 55% males. 34% had diabetes, 74% were hypertensive and 41% had hyperlipidemia. Mean LVEF was 50 ± 22% and mean TIMI risk score was 2.7 ± 1.5. There were no difference between both services in regards to the utilization of all EB therapies, BB (62 vs. 63%), ACEi (56 vs. 57%), ASA (83 vs. 80%), anticoagulation (58 vs. 63) and Statins (68 vs. 67%). Clinical outcomes including LOS (4.95 days vs. 5.14 days;
P
= .24), readmission rate (10.5% vs. 11%;
P
= .21), and all-cause mortality (4.0% vs. 3.4%;
P
= .64) were similar.
CONCLUSIONS
At our academic hospital, implementation of a standardized novel pathway for cardiac patients led to comparable outcomes between teaching and nonteaching services.
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Affiliation(s)
- Emad F Aziz
- St. Luke's-Roosevelt hospital center, New York, NY
| | | | | | - Fahad Javed
- St. Luke's-Roosevelt hospital center, New York, NY
| | - Yoon K Yang
- St. Luke's-Roosevelt hospital center, New York, NY
| | | | - Venkat Rao
- St. Luke's-Roosevelt hospital center, New York, NY
| | - Resmi Premji
- St. Luke's-Roosevelt hospital center, New York, NY
| | - Putun patel
- St. Luke's-Roosevelt hospital center, New York, NY
| | - Andre Tojino
- St. Luke's-Roosevelt hospital center, New York, NY
| | | | | | - Eyal Herzog
- St. Luke's-Roosevelt hospital center, New York, NY
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9
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Salinas N, Malhi Y, Meir P, Silman M, Roman Cuesta R, Huaman J, Salinas D, Huaman V, Gibaja A, Mamani M, Farfan F. The sensitivity of tropical leaf litter decomposition to temperature: results from a large-scale leaf translocation experiment along an elevation gradient in Peruvian forests. New Phytol 2011; 189:967-977. [PMID: 21077887 DOI: 10.1111/j.1469-8137.2010.03521.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
• We present the results from a litter translocation experiment along a 2800-m elevation gradient in Peruvian tropical forests. The understanding of the environmental factors controlling litter decomposition is important in the description of the carbon and nutrient cycles of tropical ecosystems, and in predicting their response to long-term increases in temperature. • Samples of litter from 15 species were transplanted across all five sites in the study, and decomposition was tracked over 448 d. • Species' type had a large influence on the decomposition rate (k), most probably through its influence on leaf quality and morphology. When samples were pooled across species and elevations, soil temperature explained 95% of the variation in the decomposition rate, but no direct relationship was observed with either soil moisture or rainfall. The sensitivity of the decay rate to temperature (κ(T)) varied seven-fold across species, between 0.024 and 0.169 °C⁻¹, with a mean value of 0.118 ± 0.009 °C⁻¹ (SE). This is equivalent to a temperature sensitivity parameter (Q₁₀) for litter decay of 3.06 ± 0.28, higher than that frequently assumed for heterotrophic processes. • Our results suggest that the warming of approx. 0.9 °C experienced in the region in recent decades may have increased decomposition and nutrient mineralization rates by c. 10%.
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Affiliation(s)
- N Salinas
- Environmental Change Institute, School of Geography and the Environment, South Parks Road, Oxford, OX1 3QY, UK
- Universidad Nacional de San Antonio Abad del Cusco, Peru
| | - Y Malhi
- Environmental Change Institute, School of Geography and the Environment, South Parks Road, Oxford, OX1 3QY, UK
| | - P Meir
- School of Geosciences, University of Edinburgh, Edinburgh, UK
| | | | - R Roman Cuesta
- Environmental Change Institute, School of Geography and the Environment, South Parks Road, Oxford, OX1 3QY, UK
| | - J Huaman
- Universidad Nacional de San Antonio Abad del Cusco, Peru
| | - D Salinas
- Universidad Nacional de San Antonio Abad del Cusco, Peru
| | - V Huaman
- Universidad Nacional de San Antonio Abad del Cusco, Peru
| | - A Gibaja
- Universidad Nacional de San Antonio Abad del Cusco, Peru
| | - M Mamani
- Universidad Nacional de San Antonio Abad del Cusco, Peru
| | - F Farfan
- Universidad Nacional de San Antonio Abad del Cusco, Peru
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