Luke R Iwanowicz, Ph.D. (Former Employee)
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Steroid determination in fish plasma using capillary electrophoresis
A capillary separation method that incorporates pH-mediated stacking is employed for the simultaneous determination of circulating steroid hormones in plasma from Perca flavescens (yellow perch) collected from natural aquatic environments. The method can be applied to separate eight steroid standards: progesterone, 17α,20β-dihydroxypregn-4-en-3-one, 17α-hydroxyprogesterone, testosterone, estrone,
Authors
L. Bykova, S. A. Archer-Hartmann, L.A. Holland, Luke R. Iwanowicz, Vicki S. Blazer
Mortality of centrarchid fishes in the Potomac drainage: Survey results and overview of potential contributing factors
Skin lesions and spring mortality events of smallmouth bass Micropterus dolomieu and selected other species were first noted in the South Branch of the Potomac River in 2002. Since that year morbidity and mortality have also been observed in the Shenandoah and Monocacy rivers. Despite much research, no single pathogen, parasite, or chemical cause for the lesions and mortality has been identified.
Authors
Vicki Blazer, Luke R. Iwanowicz, Clifford E. Starliper, Steven D. Zaugg, Mark R. Burkhardt, P. Barbash, J.D. Hedrick, S.J. Reeser, J.E. Mullican, J. Kelble
Author's response to "If poultry's to blame, Where's the proof?"
No abstract available.
Authors
J.L. Ripley, C. Foran, Luke R. Iwanowicz, Vicki S. Blazer
Reproductive health of bass in the potomac, USA, drainage: Part 2. Seasonal occurrence of persistent and emerging organic contaminants
The seasonal occurrence of organic contaminants, many of which are potential endocrine disruptors, entering the Potomac River, USA, watershed was investigated using a two-pronged approach during the fall of 2005 and spring of 2006. Passive samplers (semipermeable membrane device and polar organic chemical integrative sampler [POCIS]) were deployed in tandem at sites above and below wastewater trea
Authors
D.A. Alvarez, W.L. Cranor, S.D. Perkins, V.L. Schroeder, L. R. Iwanowicz, R.C. Clark, C.P. Guy, A.E. Pinkney, V. S. Blazer, J.E. Mullican
Reproductive health of bass in the potomac, USA, drainage: Part 1. exploring the effects of proximity to wastewater treatment plant discharge
Intersex (specifically, testicular oocytes) has been observed in male smallmouth bass (SMB; Micropterus dolomieu) and other centrarchids in the South Branch of the Potomac River, USA, and forks of the Shenandoah River, USA, during the past five years. This condition often is associated with exposure to estrogenic endocrine‐disrupting chemicals in some fish species, but such chemicals and their sou
Authors
L. R. Iwanowicz, V. S. Blazer, C.P. Guy, A.E. Pinkney, J.E. Mullcan, D.A. Alvarezw
Identification of centrarchid hepcidins and evidence that 17β-estradiol disrupts constitutive expression of hepcidin-1 and inducible expression of hepcidin-2 in largemouth bass (Micropterus salmoides)
Hepcidin is a highly conserved antimicrobial peptide and iron-regulatory hormone. Here, we identify two hepcidin genes (hep-1 and hep-2) in largemouth bass (Micropterus salmoides) and smallmouth bass (Micropterus dolomieu). Hepcidin-1 contains a putative ATCUN metal-binding site in the amino-terminus that is missing in hepcidin-2, suggesting that hepcidin-1 may function as an iron-regulatory hormo
Authors
L.S. Robertson, L. R. Iwanowicz, J.M. Marranca
Aroclor 1248 exposure leads to immunomodulation, decreased disease resistance and endocrine disruption in the brown bullhead, Ameiurus nebulosus
The brown bullhead Ameiurus nebulosus is a species of the family Ictaluridae commonly used as a sentinel of environmental contamination. While these fish have been utilized for this purpose in areas contaminated with polychlorinated biphenyls (PCBs), few controlled, laboratory-based studies have been designed to document the effects of PCB mixtures in this species. Here, brown bullhead were expose
Authors
L. R. Iwanowicz, V. S. Blazer, S. D. McCormick, P.A. Van Veld, C. A. Ottinger
Estrogens, estrogen receptors and their role as immunoregulators in fish
No abstract available.
Authors
Luke R. Iwanowicz, Christopher A. Ottinger
Morphology and 18S rDNA of Henneguya gurlei (Myxosporea) from Ameiurus nebulosus (Siluriformes) in North Carolina
Henneguya gurlei was isolated from Ameiurus nebulosus captured in North Carolina and redescribed using critical morphological features and 18S small-subunit ribosomal RNA (SSU rDNA) gene sequence. Plasmodia are white, spherical, or subspherical, occur in clusters, measure up to 1.8 mm in length, and are located on the dorsal, pectoral, and anal fins. Histologically, plasmodia are located in the de
Authors
L. R. Iwanowicz, D.D. Iwanowicz, L.M. Pote, V. S. Blazer, W. B. Schill
Utilization of protein expression profiles as indicators of environmental impairment of smallmouth bass (Micropterus dolomieu) from the Shenandoah River, Virginia, USA
The Shenandoah River (VA, USA), the largest tributary of the Potomac River (MD, USA) and an important source of drinking water, has been the site of extensive fish kills since 2004. Previous investigations indicate environmental stressors may be adversely modulating the immune system of smallmouth bass (Micropterus dolomieu) and other species. Anterior kidney (AK) tissue, the major site of blood c
Authors
J. Ripley, L. Iwanowicz, V. Blazer, C. Foran
Intersex (Testicular Oocytes) in smallmouth bass from the Potomac River and selected nearby drainages
Intersex, or the presence of characteristics of both sexes, in fishes that are normally gonochoristic has been used as an indicator of exposure to estrogenic compounds. In 2003, during health assessments conducted in response to kills and a high prevalence of skin lesions observed in smallmouth bass Micropterus dolomieu in the South Branch of the Potomac River, the presence of immature oocytes wit
Authors
Vicki S. Blazer, Luke R. Iwanowicz, Deborah D. Iwanowicz, David R. Smith, John A. Young, J.D. Hedrick, S.W. Foster, S.J. Reeser
Fish health study Ashtabula River natural resource damage assessment
INTRODUCTION
The Ashtabula River is located in northeast Ohio, flowing into Lake Erie at Ashtabula, Ohio. Tributaries include Fields Brook, Hubbard Run, Strong Brook, and Ashtabula Creek. The bottom sediments, bank soils and biota of Fields Brook have been severely contaminated by unregulated discharges of hazardous substances. Hazardous substances have migrated downstream from Fields Brook to
Authors
V. S. Blazer, L. R. Iwanowicz, P. C. Baumann
Non-USGS Publications**
Iwanowicz, L., L Brown, B Eltz, F Juanes and J Murt (2004) Book Review. In a Perfect Ocean: The state of fisheries and ecosystems in the North Atlantic Ocean. Reviews in Fish Biology and Fisheries.14: 149-151.
McIntire, M., L R Iwanowicz and A E Goodwin (2003) Molecular, physical and clinical evidence that Golden Shiner Virus (GSV) and Grass Carp Reovirus (GCRV) are variants of the same virus. Journal of Aquatic Animal Health. 15: 257-263.
Iwanowicz, L.R. and A E Goodwin (2002) Characterization of a new bacilliform fathead minnow rhabdovirus that produces syncytia in tissue culture. Archives of Virology 147: 889 – 916.
Iwanowicz, L.R. A E Goodwin and J Harshbarger (2001) Embryonal rhabdomyosarcoma of the giant gourami, Colisa fasciata (Bloch & Schneider). Journal of Fish Diseases 24:177-179
Iwanowicz, L.R. A E Goodwin and N Heil (2000) A small RNA virus isolated from apparently healthy wild sandbar shiners, Notropis scepticus. Journal of Fish Diseases 23: 349-352.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
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Steroid determination in fish plasma using capillary electrophoresis
A capillary separation method that incorporates pH-mediated stacking is employed for the simultaneous determination of circulating steroid hormones in plasma from Perca flavescens (yellow perch) collected from natural aquatic environments. The method can be applied to separate eight steroid standards: progesterone, 17α,20β-dihydroxypregn-4-en-3-one, 17α-hydroxyprogesterone, testosterone, estrone,AuthorsL. Bykova, S. A. Archer-Hartmann, L.A. Holland, Luke R. Iwanowicz, Vicki S. BlazerMortality of centrarchid fishes in the Potomac drainage: Survey results and overview of potential contributing factors
Skin lesions and spring mortality events of smallmouth bass Micropterus dolomieu and selected other species were first noted in the South Branch of the Potomac River in 2002. Since that year morbidity and mortality have also been observed in the Shenandoah and Monocacy rivers. Despite much research, no single pathogen, parasite, or chemical cause for the lesions and mortality has been identified.AuthorsVicki Blazer, Luke R. Iwanowicz, Clifford E. Starliper, Steven D. Zaugg, Mark R. Burkhardt, P. Barbash, J.D. Hedrick, S.J. Reeser, J.E. Mullican, J. KelbleAuthor's response to "If poultry's to blame, Where's the proof?"
No abstract available.AuthorsJ.L. Ripley, C. Foran, Luke R. Iwanowicz, Vicki S. BlazerReproductive health of bass in the potomac, USA, drainage: Part 2. Seasonal occurrence of persistent and emerging organic contaminants
The seasonal occurrence of organic contaminants, many of which are potential endocrine disruptors, entering the Potomac River, USA, watershed was investigated using a two-pronged approach during the fall of 2005 and spring of 2006. Passive samplers (semipermeable membrane device and polar organic chemical integrative sampler [POCIS]) were deployed in tandem at sites above and below wastewater treaAuthorsD.A. Alvarez, W.L. Cranor, S.D. Perkins, V.L. Schroeder, L. R. Iwanowicz, R.C. Clark, C.P. Guy, A.E. Pinkney, V. S. Blazer, J.E. MullicanReproductive health of bass in the potomac, USA, drainage: Part 1. exploring the effects of proximity to wastewater treatment plant discharge
Intersex (specifically, testicular oocytes) has been observed in male smallmouth bass (SMB; Micropterus dolomieu) and other centrarchids in the South Branch of the Potomac River, USA, and forks of the Shenandoah River, USA, during the past five years. This condition often is associated with exposure to estrogenic endocrine‐disrupting chemicals in some fish species, but such chemicals and their souAuthorsL. R. Iwanowicz, V. S. Blazer, C.P. Guy, A.E. Pinkney, J.E. Mullcan, D.A. AlvarezwIdentification of centrarchid hepcidins and evidence that 17β-estradiol disrupts constitutive expression of hepcidin-1 and inducible expression of hepcidin-2 in largemouth bass (Micropterus salmoides)
Hepcidin is a highly conserved antimicrobial peptide and iron-regulatory hormone. Here, we identify two hepcidin genes (hep-1 and hep-2) in largemouth bass (Micropterus salmoides) and smallmouth bass (Micropterus dolomieu). Hepcidin-1 contains a putative ATCUN metal-binding site in the amino-terminus that is missing in hepcidin-2, suggesting that hepcidin-1 may function as an iron-regulatory hormoAuthorsL.S. Robertson, L. R. Iwanowicz, J.M. MarrancaAroclor 1248 exposure leads to immunomodulation, decreased disease resistance and endocrine disruption in the brown bullhead, Ameiurus nebulosus
The brown bullhead Ameiurus nebulosus is a species of the family Ictaluridae commonly used as a sentinel of environmental contamination. While these fish have been utilized for this purpose in areas contaminated with polychlorinated biphenyls (PCBs), few controlled, laboratory-based studies have been designed to document the effects of PCB mixtures in this species. Here, brown bullhead were exposeAuthorsL. R. Iwanowicz, V. S. Blazer, S. D. McCormick, P.A. Van Veld, C. A. OttingerEstrogens, estrogen receptors and their role as immunoregulators in fish
No abstract available.AuthorsLuke R. Iwanowicz, Christopher A. OttingerMorphology and 18S rDNA of Henneguya gurlei (Myxosporea) from Ameiurus nebulosus (Siluriformes) in North Carolina
Henneguya gurlei was isolated from Ameiurus nebulosus captured in North Carolina and redescribed using critical morphological features and 18S small-subunit ribosomal RNA (SSU rDNA) gene sequence. Plasmodia are white, spherical, or subspherical, occur in clusters, measure up to 1.8 mm in length, and are located on the dorsal, pectoral, and anal fins. Histologically, plasmodia are located in the deAuthorsL. R. Iwanowicz, D.D. Iwanowicz, L.M. Pote, V. S. Blazer, W. B. SchillUtilization of protein expression profiles as indicators of environmental impairment of smallmouth bass (Micropterus dolomieu) from the Shenandoah River, Virginia, USA
The Shenandoah River (VA, USA), the largest tributary of the Potomac River (MD, USA) and an important source of drinking water, has been the site of extensive fish kills since 2004. Previous investigations indicate environmental stressors may be adversely modulating the immune system of smallmouth bass (Micropterus dolomieu) and other species. Anterior kidney (AK) tissue, the major site of blood cAuthorsJ. Ripley, L. Iwanowicz, V. Blazer, C. ForanIntersex (Testicular Oocytes) in smallmouth bass from the Potomac River and selected nearby drainages
Intersex, or the presence of characteristics of both sexes, in fishes that are normally gonochoristic has been used as an indicator of exposure to estrogenic compounds. In 2003, during health assessments conducted in response to kills and a high prevalence of skin lesions observed in smallmouth bass Micropterus dolomieu in the South Branch of the Potomac River, the presence of immature oocytes witAuthorsVicki S. Blazer, Luke R. Iwanowicz, Deborah D. Iwanowicz, David R. Smith, John A. Young, J.D. Hedrick, S.W. Foster, S.J. ReeserFish health study Ashtabula River natural resource damage assessment
INTRODUCTION The Ashtabula River is located in northeast Ohio, flowing into Lake Erie at Ashtabula, Ohio. Tributaries include Fields Brook, Hubbard Run, Strong Brook, and Ashtabula Creek. The bottom sediments, bank soils and biota of Fields Brook have been severely contaminated by unregulated discharges of hazardous substances. Hazardous substances have migrated downstream from Fields Brook toAuthorsV. S. Blazer, L. R. Iwanowicz, P. C. BaumannNon-USGS Publications**
Iwanowicz, L., L Brown, B Eltz, F Juanes and J Murt (2004) Book Review. In a Perfect Ocean: The state of fisheries and ecosystems in the North Atlantic Ocean. Reviews in Fish Biology and Fisheries.14: 149-151.McIntire, M., L R Iwanowicz and A E Goodwin (2003) Molecular, physical and clinical evidence that Golden Shiner Virus (GSV) and Grass Carp Reovirus (GCRV) are variants of the same virus. Journal of Aquatic Animal Health. 15: 257-263.Iwanowicz, L.R. and A E Goodwin (2002) Characterization of a new bacilliform fathead minnow rhabdovirus that produces syncytia in tissue culture. Archives of Virology 147: 889 – 916.Iwanowicz, L.R. A E Goodwin and J Harshbarger (2001) Embryonal rhabdomyosarcoma of the giant gourami, Colisa fasciata (Bloch & Schneider). Journal of Fish Diseases 24:177-179Iwanowicz, L.R. A E Goodwin and N Heil (2000) A small RNA virus isolated from apparently healthy wild sandbar shiners, Notropis scepticus. Journal of Fish Diseases 23: 349-352.**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
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*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government