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Smith SV. The COVID‐19 Pandemic and Its Effects on Student Performance in Medical Pharmacology. FASEB J 2022. [PMCID: PMC9347526 DOI: 10.1096/fasebj.2022.36.s1.r6371] [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: 11/11/2022]
Affiliation(s)
- Stanley V. Smith
- PharmacologyThe University of Mississippi Medical CenterJacksonMS
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2
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Poudel B, Shields CA, Ekperikpe US, Brown AK, Travis OK, Maury JC, Fitzgerald S, Smith SV, Cornelius DC, Williams JM. The SS LepR mutant rat represents a novel model to study obesity-induced renal injury before puberty. Am J Physiol Regul Integr Comp Physiol 2022; 322:R299-R308. [PMID: 35107024 PMCID: PMC8917907 DOI: 10.1152/ajpregu.00179.2021] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 01/26/2022] [Accepted: 01/26/2022] [Indexed: 02/08/2023]
Abstract
Prepubertal obesity (PPO) has emerged as a major health problem over the past few decades and is a risk factor for the development of proteinuria. The current study investigated whether the development of renal injury in the obese SSLepR mutant strain occurs before puberty. When determining the temporal changes in serum sex hormones in female and male SS and SSLepR mutant rats between 4 and 10 wk of age, we only observed significant increases in estradiol and testosterone levels in female and male SS rats at 10 wk of age than at 4 wk of age. The results suggest that studying both strains between 4 and 8 wk of age is appropriate to study the effects of PPO on renal injury in this model. Proteinuria was significantly higher in SSLepR mutant rats as opposed to the values observed in SS rats at 8 wk of age, and we did not observe any sex differences in proteinuria in either strain. The kidneys from the SSLepR mutant rats displayed significant glomerular and tubular injury and renal fibrosis versus the values measured in SS rats without any sex differences. Overall, we observed increased immune cell infiltration in the kidneys from SSLepR mutant rats compared with SS rats. Interestingly, female SSLepR mutant rats displayed significant increases in not only M1 macrophages (proinflammatory) but also M2 macrophages (anti-inflammatory) versus male SSLepR mutant rats. These results suggest the SSLepR mutant rat may be a useful model to study early progression of obesity-related renal injury before the onset of puberty.
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Affiliation(s)
- Bibek Poudel
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Corbin A Shields
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Ubong S Ekperikpe
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Andrea K Brown
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Olivia K Travis
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Jordan C Maury
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Sarah Fitzgerald
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Stanley V Smith
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Denise C Cornelius
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
- Department of Emergency Medicine, University of Mississippi Medical Center, Jackson, Mississippi
| | - Jan M Williams
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
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3
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Wang S, Jiao F, Border JJ, Fang X, Crumpler RF, Liu Y, Zhang H, Jefferson J, Guo Y, Elliott PS, Thomas KN, Strong LB, Urvina AH, Zheng B, Rijal A, Smith SV, Yu H, Roman RJ, Fan F. Luseogliflozin, a sodium-glucose cotransporter-2 inhibitor, reverses cerebrovascular dysfunction and cognitive impairments in 18-mo-old diabetic animals. Am J Physiol Heart Circ Physiol 2022; 322:H246-H259. [PMID: 34951541 PMCID: PMC8759958 DOI: 10.1152/ajpheart.00438.2021] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Diabetes mellitus (DM) is a leading risk factor for age-related dementia, but the mechanisms involved are not well understood. We previously discovered that hyperglycemia induced impaired myogenic response (MR) and cerebral blood flow (CBF) autoregulation in 18-mo-old DM rats associated with blood-brain barrier (BBB) leakage, impaired neurovascular coupling, and cognitive impairment. In the present study, we examined whether reducing plasma glucose with a sodium-glucose cotransporter-2 inhibitor (SGLT2i) luseogliflozin can ameliorate cerebral vascular and cognitive function in diabetic rats. Plasma glucose and HbA1c levels of 18-mo-old DM rats were reduced, and blood pressure was not altered after treatment with luseogliflozin. SGLT2i treatment restored the impaired MR of middle cerebral arteries (MCAs) and parenchymal arterioles and surface and deep cortical CBF autoregulation in DM rats. Luseogliflozin treatment also rescued neurovascular uncoupling, reduced BBB leakage and cognitive deficits in DM rats. However, SGLT2i did not have direct constrictive effects on vascular smooth muscle cells and MCAs isolated from normal rats, although it decreased reactive oxygen species production in cerebral vessels of DM rats. These results provide evidence that normalization of hyperglycemia with an SGLT2i can reverse cerebrovascular dysfunction and cognitive impairments in rats with long-standing hyperglycemia, possibly by ameliorating oxidative stress-caused vascular damage.NEW & NOTEWORTHY This study demonstrates that luseogliflozin, a sodium-glucose cotransporter-2 inhibitor, improved CBF autoregulation in association with reduced vascular oxidative stress and AGEs production in the cerebrovasculature of 18-mo-old DM rats. SGLT2i also prevented BBB leakage, impaired functional hyperemia, neurodegeneration, and cognitive impairment seen in DM rats. Luseogliflozin did not have direct constrictive effects on VSMCs and MCAs isolated from normal rats. These results provide evidence that normalization of hyperglycemia with an SGLT2i can reverse cerebrovascular dysfunction and cognitive impairments in rats with long-standing hyperglycemia, possibly by ameliorating oxidative stress-caused vascular damage.
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Affiliation(s)
- Shaoxun Wang
- 1Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Feng Jiao
- 1Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Jane J. Border
- 1Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Xing Fang
- 1Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Reece F. Crumpler
- 1Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Yedan Liu
- 1Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Huawei Zhang
- 1Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Joshua Jefferson
- 1Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Ya Guo
- 1Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Parker S. Elliott
- 1Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Kirby N. Thomas
- 1Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Luke B. Strong
- 1Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Austin H. Urvina
- 1Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Baoying Zheng
- 1Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Arjun Rijal
- 1Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Stanley V. Smith
- 1Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Hongwei Yu
- 2Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Richard J. Roman
- 1Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Fan Fan
- 1Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
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Hirata T, Smith SV, Takahashi T, Miyata N, Roman RJ. Increased Levels of Renal Lysophosphatidic Acid in Rodent Models with Renal Disease. J Pharmacol Exp Ther 2020; 376:240-249. [PMID: 33277348 DOI: 10.1124/jpet.120.000353] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 12/01/2020] [Indexed: 12/29/2022] Open
Abstract
Lysophosphatidic acid (LPA) is a bioactive lipid mediator that has been implicated in the pathophysiology of kidney disease. However, few studies have attempted to measure changes in the levels of various LPA species in the kidney after the development of renal disease. The present study measured the renal LPA levels during the development of kidney disease in rat models of hypertension, diabetes, and obstructive nephropathy using liquid chromatography/mass spectrometry/mass spectrometry. LPA levels (sum of 16:0, 18:0, 18:1, 18:2, and 20:4 LPA) were higher in the renal cortex of hypertensive Dahl salt-sensitive (Dahl S) rats fed a high-salt diet than those in normotensive rats fed a low-salt diet (296.6 ± 22.9 vs. 196.3 ± 8.5 nmol/g protein). LPA levels were elevated in the outer medulla of the kidney of streptozotocin-induced type 1 diabetic Dahl S rats compared with control rats (624.6 ± 129.5 vs. 318.8 ± 17.1 nmol/g protein). LPA levels were also higher in the renal cortex of 18-month-old, type 2 diabetic nephropathy (T2DN) rats with more severe renal injury than in 6-month-old T2DN rats (184.9 ± 20.9 vs. 116.9 ± 6.0 nmol/g protein). LPA levels also paralleled the progression of renal fibrosis in the renal cortex of Sprague-Dawley rats after unilateral ureteral obstruction (UUO). Administration of an LPA receptor antagonist, Ki16425, reduced the degree of renal fibrosis in UUO rats. These results suggest that the production of renal LPA increases during the development of renal injury and contributes to renal fibrosis. SIGNIFICANCE STATEMENT: The present study reveals that the lysophosphatidic acid (LPA) levels increase in the kidney in rat models of hypertension, diabetes, and obstructive nephropathy, and administration of an LPA receptor antagonist attenuates renal fibrosis. Therapeutic approaches that target the formation or actions of renal LPA might be renoprotective and have therapeutic potential.
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Affiliation(s)
- Takashi Hirata
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi (T.H., S.V.S., R.J.R.); and Pharmacology Laboratories (T.H., T.T.) and Research Headquarters of Pharmaceutical Operation (N.M.), Taisho Pharmaceutical Co., Ltd., Saitama, Japan
| | - Stanley V Smith
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi (T.H., S.V.S., R.J.R.); and Pharmacology Laboratories (T.H., T.T.) and Research Headquarters of Pharmaceutical Operation (N.M.), Taisho Pharmaceutical Co., Ltd., Saitama, Japan
| | - Teisuke Takahashi
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi (T.H., S.V.S., R.J.R.); and Pharmacology Laboratories (T.H., T.T.) and Research Headquarters of Pharmaceutical Operation (N.M.), Taisho Pharmaceutical Co., Ltd., Saitama, Japan
| | - Noriyuki Miyata
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi (T.H., S.V.S., R.J.R.); and Pharmacology Laboratories (T.H., T.T.) and Research Headquarters of Pharmaceutical Operation (N.M.), Taisho Pharmaceutical Co., Ltd., Saitama, Japan
| | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi (T.H., S.V.S., R.J.R.); and Pharmacology Laboratories (T.H., T.T.) and Research Headquarters of Pharmaceutical Operation (N.M.), Taisho Pharmaceutical Co., Ltd., Saitama, Japan
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Huffman AM, Syed M, Rezq S, Anderson CD, Smith SV, Harmancey R, Yanes Cardozo LL, Romero DG. MicroRNA‐21 Ablation Attenuates Acetaminophen‐Induced Hepatoxtoxicity in Male Mice. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.03494] [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: 11/11/2022]
Affiliation(s)
| | | | - Samar Rezq
- University of Mississippi Medical Center
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Poole AR, Enwerem II, Vicino IA, Coole JB, Smith SV, Hebert MD. Identification of processing elements and interactors implicate SMN, coilin and the pseudogene-encoded coilp1 in telomerase and box C/D scaRNP biogenesis. RNA Biol 2016; 13:955-972. [PMID: 27419845 DOI: 10.1080/15476286.2016.1211224] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Many cellular functions, such as translation, require ribonucleoproteins (RNPs). The biogenesis of RNPs is a multi-step process that, depending on the RNP, can take place in many cellular compartments. Here we examine 2 different RNPs: telomerase and small Cajal body-specific RNPs (scaRNPs). Both of these RNPs are enriched in the Cajal body (CB), which is a subnuclear domain that also has high concentrations of another RNP, small nuclear RNPs (snRNPs). SnRNPs are essential components of the spliceosome, and scaRNPs modify the snRNA component of the snRNP. The CB contains many proteins, including WRAP53, SMN and coilin, the CB marker protein. We show here that coilin, SMN and coilp1, a newly identified protein encoded by a pseudogene in human, associate with telomerase RNA and a subset of scaRNAs. We also have identified a processing element within box C/D scaRNA. Our findings thus further strengthen the connection between the CB proteins coilin and SMN in the biogenesis of telomeras e and box C/D scaRNPs, and reveal a new player, coilp1, that likely participates in this process.
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Affiliation(s)
- Aaron R Poole
- a Department of Biochemistry , The University of Mississippi Medical Center , Jackson , MS , USA
| | - Isioma I Enwerem
- a Department of Biochemistry , The University of Mississippi Medical Center , Jackson , MS , USA
| | - Ian A Vicino
- a Department of Biochemistry , The University of Mississippi Medical Center , Jackson , MS , USA
| | - Jackson B Coole
- a Department of Biochemistry , The University of Mississippi Medical Center , Jackson , MS , USA
| | - Stanley V Smith
- b Department of Pharmacology and Toxicology , The University of Mississippi Medical Center , Jackson , MS , USA
| | - Michael D Hebert
- a Department of Biochemistry , The University of Mississippi Medical Center , Jackson , MS , USA
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Fan F, Geurts AM, Pabbidi MR, Smith SV, Harder DR, Jacob H, Roman RJ. Zinc-finger nuclease knockout of dual-specificity protein phosphatase-5 enhances the myogenic response and autoregulation of cerebral blood flow in FHH.1BN rats. PLoS One 2014; 9:e112878. [PMID: 25397684 PMCID: PMC4232417 DOI: 10.1371/journal.pone.0112878] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 10/18/2014] [Indexed: 12/11/2022] Open
Abstract
We recently reported that the myogenic responses of the renal afferent arteriole (Af-Art) and middle cerebral artery (MCA) and autoregulation of renal and cerebral blood flow (RBF and CBF) were impaired in Fawn Hooded hypertensive (FHH) rats and were restored in a FHH.1BN congenic strain in which a small segment of chromosome 1 from the Brown Norway (BN) containing 15 genes including dual-specificity protein phosphatase-5 (Dusp5) were transferred into the FHH genetic background. We identified 4 single nucleotide polymorphisms in the Dusp5 gene in FHH as compared with BN rats, two of which altered CpG sites and another that caused a G155R mutation. To determine whether Dusp5 contributes to the impaired myogenic response in FHH rats, we created a Dusp5 knockout (KO) rat in the FHH.1BN genetic background using a zinc-finger nuclease that introduced an 11 bp frame-shift deletion and a premature stop codon at AA121. The expression of Dusp5 was decreased and the levels of its substrates, phosphorylated ERK1/2 (p-ERK1/2), were enhanced in the KO rats. The diameter of the MCA decreased to a greater extent in Dusp5 KO rats than in FHH.1BN and FHH rats when the perfusion pressure was increased from 40 to 140 mmHg. CBF increased markedly in FHH rats when MAP was increased from 100 to 160 mmHg, and CBF was better autoregulated in the Dusp5 KO and FHH.1BN rats. The expression of Dusp5 was higher at the mRNA level but not at the protein level and the levels of p-ERK1/2 and p-PKC were lower in cerebral microvessels and brain tissue isolated from FHH than in FHH.1BN rats. These results indicate that Dusp5 modulates myogenic reactivity in the cerebral circulation and support the view that a mutation in Dusp5 may enhance Dusp5 activity and contribute to the impaired myogenic response in FHH rats.
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Affiliation(s)
- Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Aron M. Geurts
- Human and Molecular Genetics Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Mallikarjuna R. Pabbidi
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Stanley V. Smith
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - David R. Harder
- Department of Physiology and Cardiovascular Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Howard Jacob
- Human and Molecular Genetics Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Richard J. Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
- * E-mail:
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Dreisbach AW, Smith SV, Kyle PB, Ramaiah M, Amenuke M, Garrett MR, Lirette ST, Griswold ME, Roman RJ. Urinary CYP eicosanoid excretion correlates with glomerular filtration in African-Americans with chronic kidney disease. Prostaglandins Other Lipid Mediat 2014; 113-115:45-51. [PMID: 25151892 DOI: 10.1016/j.prostaglandins.2014.08.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [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: 11/07/2013] [Revised: 07/29/2014] [Accepted: 08/04/2014] [Indexed: 12/25/2022]
Abstract
Previous studies have indicated that cytochrome P450 (CYP) metabolites of arachidonic acid (AA), i.e., 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acids (EETs), play an important role in the regulation of renal tubular and vascular function. The present study for the first time profiled HETEs and epoxygenase derived dihydroxyeicosatetraenoic acid diHETEs levels in spot urines and plasma in 262 African American patients from the University of Mississippi Chronic Kidney Disease Clinic and 31 African American controls. Significant correlations in eGFR and urinary 20-HETE/creatinine and 19-HETE/creatinine levels were observed. The eGFR increased by 17.47 [p=0.001] and 60.68 [(p=0.005]ml/min/for each ng/mg increase in 20-HETE and 19-HETE levels, respectively. Similar significant positive associations were found between the other urinary eicosanoids and eGFR and also with 19-HETE/urine creatinine concentration and proteinuria. We found that approximately 80% of plasma HETEs and 30% diHETEs were glucuronidated and the fractional excretion of 20-HETE was less than 1%. These results suggest that there is a significant hepatic source of urinary 20-HETE glucuronide and EETs with extensive renal biotransformation to metabolites which may play a role in the pathogenesis of CKD.
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Affiliation(s)
- Albert W Dreisbach
- Department of Medicine, University of Mississippi Medical Center, Jackson, MS, United States.
| | - Stanley V Smith
- Department of Pharmacology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Patrick B Kyle
- Department of Pathology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Manjunath Ramaiah
- Department of Hospital Medicine, Hattiesburg Clinic, Hattiesburg, MS, United States
| | - Margaret Amenuke
- Department of Medicine, University of Mississippi Medical Center, Jackson, MS, United States
| | - Michael R Garrett
- Department of Pharmacology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Seth T Lirette
- Center for Biostatistics and Bioinformatics, University of Mississippi Medical Center, Jackson, MS, United States
| | - Michael E Griswold
- Center for Biostatistics and Bioinformatics, University of Mississippi Medical Center, Jackson, MS, United States
| | - Richard J Roman
- Department of Pharmacology, University of Mississippi Medical Center, Jackson, MS, United States
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Dreisbach A, Smith SV, Kyle PB, Ramaiah M, Garrett MR, Amenuke M, Griswold ME, Roman RJ. Abstract 348: Urinary CYP Eicosanoid Excretion Correlates with Glomerular Filtration in African-Americans with Chronic Kidney Disease. Hypertension 2012. [DOI: 10.1161/hyp.60.suppl_1.a348] [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]
Abstract
Previous studies have indicated that cytochrome P450 (CYP) metabolites of arachidonic acid, ie, 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acids (EETs) play an important role in the regulation of renal tubular function and vascular tone. More recent studies suggest that variants in the
CYP4A11
and
CYP4F2
genes are linked to the development of hypertension in a variety of human population studies. However, little is known about the role of 20-HETE or EETs in the pathogenesis of hypertension or diabetic induced renal disease because CYP eicosanoids have not been measured in patients with CKD. The present study profiled HETEs and the dihydroxy metabolites of EETs (DHETs) levels, from spot urines at the time of their clinic visit using LC/MS/MS in 106 African-American patients from the University of Mississippi (UMC) Chronic Kidney Disease (CKD) Clinic with various etiologies of renal disease. Informed consent was obtained for this UMMC IRB approved protocol. Significant positive correlations were found between urinary 5,6- DHETE, 8,9-DHETE, 11,12-DIHETE, 14,15-DHETE, 20-HETE and 19-, 15- and 8-HETE levels and estimated GFR (eGFR) as derived from the MDRD. The magnitude of the influence of urinary eicosanoid levels on eGFR was relatively profound since the slopes of these relationships indicated that there is a 5-10% decrement eGFR associated with each ng/ml fall in urinary eicosanoid levels. These results suggest that a decline in the renal formation of 20-HETE and/or EETs may contribute to the pathogenesis of CKD. At very least, urinary CYP eicosanoids may serve as a useful biomarker for progressive disease.
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Kyle PB, Smith SV, Baker RC, Kramer RE. Mass spectrometric detection of CYP450 adducts following oxidative desulfuration of methyl parathion. J Appl Toxicol 2012; 33:644-51. [DOI: 10.1002/jat.1792] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 11/10/2011] [Accepted: 11/15/2011] [Indexed: 11/10/2022]
Affiliation(s)
- Patrick B. Kyle
- Department of Pathology; University of Mississippi Medical Center; Jackson; Mississippi; USA
| | - Stanley V. Smith
- Department of Pharmacology and Toxicology; University of Mississippi Medical Center; Jackson; Mississippi; USA
| | - Rodney C. Baker
- Department of Pharmacology and Toxicology; University of Mississippi Medical Center; Jackson; Mississippi; USA
| | - Robert E. Kramer
- Department of Pharmacology and Toxicology; University of Mississippi Medical Center; Jackson; Mississippi; USA
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Fong N, Guagliardo P, Williams J, Musumeci A, Martin D, Smith SV. Clay particles - potential of positron annihilation lifetime spectroscopy (PALS) for studying interlayer spacing. ACTA ACUST UNITED AC 2011. [DOI: 10.1088/1742-6596/262/1/012022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Sellaiyan S, Smith SV, Hughes AE, Miller A, Jenkins DR, Uedono A. Understanding the effect of nanoporosity on optimizing the performance of self-healing materials for anti-corrosion applications. ACTA ACUST UNITED AC 2011. [DOI: 10.1088/1742-6596/262/1/012054] [Citation(s) in RCA: 2] [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: 11/11/2022]
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Abstract
Corals and algal pavement produce calcium carbonate more slowly on the windward reef slope of Enewetak Atoll than on the reef flat despite the high standing crop of reef-building organisms on the slope. The capacity of reefs to remain at or near sea level is therefore not determined primarily by growth on the seaward slope.
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Abstract
Marine macrophyte biomass production, burial, oxidation, calcium carbonate dissolution, and metabolically accelerated diffusion of carbon dioxide across the air-sea interface may combine to sequester at least 10(9) tons of carbon per year in the ocean. This carbon sink may partially account for discrepancies in extant global carbon budgets.
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Cutler CS, McQuarrie S, Smith SV. Imagine the imagery: opportunities and challenges. Q J Nucl Med Mol Imaging 2008; 52:212-214. [PMID: 18480739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- C S Cutler
- University of Missouri, Research Reactor Center, Columbia, MO, USA.
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Jurisson S, Cutler C, Smith SV. Radiometal complexes: characterization and relevant in vitro studies. Q J Nucl Med Mol Imaging 2008; 52:222-234. [PMID: 18480740] [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] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Radiometals are, and will continue to be, very important to diagnostic and therapeutic nuclear medicine applications as they predominantly possess the most suitable nuclear properties for these types of applications. This article attempts to give the reader an overview of key aspects that need to be considered in the design and synthesis of a radiopharmaceutical using the commonly known and employed radionuclides, such as technetium, rhenium, the lanthanides and copper. While it is important to understand each radiometal ion has its own specific coordination chemistry requirements, there are several issues that are critical to all radiometal ions for their incorporation into a radiopharmaceutical. 1) The route of production and the presence of long lived contaminating radionuclides and or of naturally occurring metal ions that will interfere with the efficient and optimum radiolabelling of their ligand of choice as well as the final specific activity of the product; 2) the significant differences between the chemistry at the macroscopic (mM and higher concentrations) and radiotracer levels (uM and lower concentrations for the high specific activity radionuclides); 3) the rate of complexation and of dissociation of the radiometal ion vs the competing reaction of radiometal hydrolysis; 4) natural biological pathway of the radio-metal ion and therefore the design of the appropriate and relevant in vitro tests to assess the stability of the radiometal complex. These are a selection of critical factors that need to be considered in the design of a successful radiopharmaceutical, whether it is used for imaging or therapy. However, one should consider tailoring their investigations to suit the radiometal under investigation, and to be mindful where the technology is to be applied (e.g. imaging organs or disease).
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Affiliation(s)
- S Jurisson
- Department of Chemistry, University of Missouri, Columbia, MO, USA
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Smith SV. Sarar technology for the application of Copper-64 in biology and materials science. Q J Nucl Med Mol Imaging 2008; 52:193-202. [PMID: 18174877] [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] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
This review provides an overview of the synthesis and metal complexation chemistry of the nitrogen and sulphur donor bicyclic ligands or cages, and the key criteria that led to the design of sarar for the application for (64)Cu(II). Aspects of the high yielding synthesis of sarar and strategies for its conjugation to a range of antibodies for targeting colorectal cancer, neuroblastoma and melanoma are described. Free and conjugated to proteins sarar can complex (64)Cu(II) rapidly at room temperature and quantitatively; the latter leading to products of high specific activity and purity. The full occupation of the (64)Cu(II) ions 6 coordination sites by the sarar cage prevents the ready exchange of the (64)Cu(II) from the cage and is the rational for the extraordinary thermodynamic and kinetic stability of (64)Cu(II) labelled sarar and its conjugates. It's in vivo stability is further highlighted by the low uptake and retention of (64)Cu-sarar-conjugated antibodies in the liver. Finally, the prospects for the use of the sarar technology in the materials science arena for probing solid liquid interfaces, in particular, the quantification of functional groups on microspheres and in the engineering of novel materials are discussed.
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Affiliation(s)
- S V Smith
- Centre of Excellence in Antimatter-Matter Studies, (ARC CAMS), Australia.
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Smith SV, Bullock SH, Hinojosa-Corona A, Franco-Vizcaíno E, Escoto-Rodríguez M, Kretzschmar TG, Farfán LM, Salazar-Ceseña JM. Soil erosion and significance for carbon fluxes in a mountainous Mediterranean-climate watershed. Ecol Appl 2007; 17:1379-87. [PMID: 17708215 DOI: 10.1890/06-0615.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
In topographically complex terrains, downslope movement of soil organic carbon (OC) can influence local carbon balance. The primary purpose of the present analysis is to compare the magnitude of OC displacement by erosion with ecosystem metabolism in such a complex terrain. Does erosion matter in this ecosystem carbon balance? We have used the Revised Universal Soil Loss Equation (RUSLE) erosion model to estimate lateral fluxes of OC in a watershed in northwestern Mexico. The watershed (4900 km2) has an average slope of 10 degrees +/- 9 degrees (mean +/- SD); 45% is >10 degrees, and 3% is >30 degrees. Land cover is primarily shrublands (69%) and agricultural lands (22%). Estimated bulk soil erosion averages 1350 Mg x km(-2) x yr(-1). We estimate that there is insignificant erosion on slopes < 2 degrees and that 20% of the area can be considered depositional. Estimated OC erosion rates are 10 Mg x km(-2) x yr(-1) for areas steeper than 2 degrees. Over the entire area, erosion is approximately 50% higher on shrublands than on agricultural lands, but within slope classes, erosion rates are more rapid on agricultural areas. For the whole system, estimated OC erosion is approximately 2% of net primary production (NPP), increasing in high-slope areas to approximately 3% of NPP. Deposition of eroded OC in low-slope areas is approximately 10% of low-slope NPP. Soil OC movement from erosional slopes to alluvial fans alters the mosaic of OC metabolism and storage across the landscape.
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Affiliation(s)
- S V Smith
- Departamento de Geología, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California 22860 Mexico.
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Smith SV, Robinson RC, Smith TG, Burks SM, Friedman FK. Rapid Conformational Dynamics of Cytochrome P450 2E1 in a Natural Biological Membrane Environment†. Biochemistry 2006; 45:15617-23. [PMID: 17176083 DOI: 10.1021/bi061873u] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [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: 10/23/2022]
Abstract
Among the members of the cytochrome P450 superfamily, P450 2E1 is most often associated with the production of reactive oxygen species and subsequent cellular toxicity. We sought to identify a structural basis for this distinguishing feature of P450 2E1 by examining its carbon monoxide binding kinetics as a probe of conformation/dynamics. We employed liver microsomes from wild-type and P450 2E1 knockout mice in order to characterize this P450 in a natural membrane environment. The CO binding kinetics of the P450s of wild-type microsomes had a rapid component that was absent in the knockout microsomes. Data analysis using the maximum entropy method (MEM) correspondingly identified two distinct kinetic components in the wild-type microsomes and only one component in the knockout microsomes. The rapid kinetic component in wild-type microsomes was attributed to endogenous P450 2E1, while the slower component was derived from the remaining P450s. In addition, rapid binding kinetics and a single component were also observed for human P450 2E1 in a baculovirus expression system, in the absence of other P450s. Binding kinetics of both mouse and human P450 2E1 were slowed in the presence of ethanol, a modulator of this P450. The unusually rapid CO binding kinetics of P450 2E1 indicate that it is more dynamically mobile than other P450s and thus able to more readily interconvert among alternate conformations. This suggests that conformational switching during the catalytic cycle may promote substrate release from a short-lived binding site, allowing activated oxygen to attack other targets with toxic consequences.
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Affiliation(s)
- Stanley V Smith
- Department of Pharmacology and Toxicology, The University of Mississippi Medical Center, Jackson, Mississippi 39216-4505, USA.
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Duatti A, Smith SV. Communicating across the boundaries. Q J Nucl Med Mol Imaging 2006; 50:245-7. [PMID: 17043622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
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Affiliation(s)
- W H Renwick
- Department of Geography, Miami University, Oxford, OH 45056, USA.
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MacKenzie FM, Smith SV, Milne KE, Griffiths K, Legge J, Gould IM. Antibiograms of resistant Gram-negative bacteria from Scottish CF patients. J Cyst Fibros 2004; 3:151-7. [PMID: 15463901 DOI: 10.1016/j.jcf.2004.03.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2003] [Accepted: 03/24/2004] [Indexed: 11/22/2022]
Abstract
BACKGROUND Over a 19-month pilot phase, 93 multiply resistant Gram-negative isolates from Scottish cystic fibrosis patients were sent to a referral laboratory for further investigation. METHODS In common with the referring diagnostic laboratories, disc diffusion testing was carried out. Antibiotic susceptibility testing was also established by MIC methodology. NCCLS methods were used throughout. Twenty antibiotics were tested. RESULTS Comparing disc diffusion results against MIC results, there were 167 (14%) major errors. By MIC, Pseudomonas aeruginosa (n = 59), Stenotrophomonas maltophilia (n = 16), Burkholderia cepacia (n = 10) and Alcaligenes xylosoxidans (n = 7) were susceptible to 18%, 11%, 4% and 35% of the antibiotics tested, respectively. Colistin and tobramycin were the most active agents against P. aeruginosa with 60% and 49%, respectively, testing susceptible. Minocycline and gentamicin were most active against S. maltophilia with 58% and 18%, respectively, testing susceptible. B. cepacia were most susceptible to co-trimoxazole (10%) and ciprofloxacin (10%). Five and six of the seven A. xylosoxidans isolates were susceptible to piperacillin and imipenem, respectively. CONCLUSIONS Improved methods for susceptibility testing of such clinical isolates need to be employed in routine diagnostic laboratories. Levels of resistance in referred isolates were very high and similar to those described in the USA.
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Affiliation(s)
- F M MacKenzie
- Department of Medical Microbiology, Aberdeen Royal Infirmary, Foresterhill, Aberdeen AB25 2ZN, UK
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Abstract
Reproductive health programs should adopt an approach based on human rights at the levels of clinical management as well as national policy, especially those programs responsible for abortion and post-abortion care. Resource-poor women face greater maternal mortality and morbidity, suffer continuous risk because of a lack of access to adequate reproductive health services, and are likelier than more affluent women to resort to unsafe, inaccessible, and/or unaffordable abortion services. The public health and medical communities are highly effective when providing safe abortion procedures and treatment in the event of complications. Efforts must be continued to develop strategies to prevent unwanted pregnancies, unsafe abortions, and abortion-related deaths; to treat abortion complications; to broaden the types of medical and health professionals who are allowed to perform abortions; and to enhance training for abortion providers.
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Affiliation(s)
- K Yanda
- Mailman School of Public Health, Columbia University, New York, NY, USA
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Smith SV, Renwick WH, Bartley JD, Buddemeier RW. Distribution and significance of small, artificial water bodies across the United States landscape. Sci Total Environ 2002; 299:21-36. [PMID: 12462572 DOI: 10.1016/s0048-9697(02)00222-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
At least 2.6 million small, artificial water bodies dot the landscape of the conterminous United States; most are in the eastern half of the country. These features account for approximately 20% of the standing water area across the United States, and their impact on hydrology, sedimentology, geochemistry, and ecology is apparently large in proportion to their area. These features locally elevate evaporation, divert and delay downstream water flow, and modify groundwater interactions. They apparently intercept about as much eroded soil as larger, better-documented reservoirs. Estimated vertical accretion rates are much higher, hence, inferred sedimentary chemical reactions must be different in the small features than in larger ones. Finally, these features substantially alter the characteristics of aquatic habitats across the landscape.
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Affiliation(s)
- S V Smith
- Department of Oceanography, University of Hawaii, Honolulu, HI 96822, USA.
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Montalto M, Gilfillan CP, Dutta D, Cole S, Avery C, Smith SV. Inpatient insulin initiation using a hospital in the home unit. Intern Med J 2001; 31:492-4. [PMID: 11720064 DOI: 10.1046/j.1445-5994.2001.00106.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- M Montalto
- Epworth Hospital, Melbourne, Victoria, Australia.
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Piro MC, Militello V, Leone M, Gryczynski Z, Smith SV, Brinigar WS, Cupane A, Friedman FK, Fronticelli C. Heme pocket disorder in myoglobin: reversal by acid-induced soft refolding. Biochemistry 2001; 40:11841-50. [PMID: 11570884 DOI: 10.1021/bi010652f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [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: 11/29/2022]
Abstract
The protein folding process of heme proteins entails generation of not only a correct global polypeptide structure, but also a correct, functionally competent heme environment. We employed a variety of spectroscopic approaches to probe the structure and dynamics of the heme pocket of a recombinant sperm whale myoglobin. The conformational characteristics were examined by circular dichroism, time-resolved fluorescence spectroscopy, FTIR spectroscopy, and optical absorption spectroscopy in the temperature range 300-20 K. Each of these spectroscopic probes detected modifications confined exclusively to the heme pocket of the expressed myoglobin relative to the native protein. The functional properties were examined by measuring the kinetics of CO binding after flash-photolysis. The kinetics of the expressed myoglobin were more heterogeneous than those of the native protein. Mild acid exposure of the ferric derivative of the recombinant protein resulted in a protein with "nativelike" spectroscopic properties and homogeneous CO binding kinetics. The heme pocket modifications observed in this recombinant myoglobin do not derive from inverted heme. In contrast, when native apomyoglobin is reconstituted with the heme in vitro, the heme pocket disorder could be attributed exclusively to 180 degrees rotation of the bound heme [La Mar, G. N., Toi, H., and Krishnamoorthi, R. (1984) J. Am. Chem. Soc. 106, 6395-6401; Light, W. R., Rohlfs, R. J., Palmer, G., and Olson, J. S. (1987) J. Biol. Chem. 262, 46-52]. We conclude that exposure to low pH decreases the affinity of globin for the heme and allows an extended conformational sampling or "soft refolding" to a nativelike conformation.
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Affiliation(s)
- M C Piro
- Department of Biochemistry and Molecular Biology, University of Maryland Medical School, Baltimore, Maryland 21201, USA
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Smith SV. SGN-10. Seattle Genetics. Curr Opin Investig Drugs 2001; 2:1314-9. [PMID: 11717821] [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] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Seattle Genetics is developing SGN-10 (BR96-SCIT), a single-chain immunotoxin (SCIT) under license from Bristol-Myers Squibb (BMS), as both a monotherapy and in combination with Taxotere (Rhône-Poulenc Rorer) for the potential treatment for cancer [308773]. SGN-10 is currently in phase I clinical trials [308773], [369809], [382807], [408963], [410348]. The compound is a follow-up to SGN-15 (BR96-DOX; BMS) and is potentially more effective and cheaper to manufacture. It delivers a bacterial toxin which is 250-times more potent than BR96-DOX and is one third the size, hence enabling tumor penetration more easily. BMS submitted an IND for SGN-10 in the first quarter of 1996 [200849], [204704]. BMS licensed the SCA-protein (single-chain antigen-binding protein) technology from Enzon in 1993 [352743]. In April 1998, Seattle Genetics completed a licensing agreement with BMS to take over development of SGN-10 [308773].
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Behar TN, Smith SV, Kennedy RT, McKenzie JM, Maric I, Barker JL. GABA(B) receptors mediate motility signals for migrating embryonic cortical cells. Cereb Cortex 2001; 11:744-53. [PMID: 11459764 DOI: 10.1093/cercor/11.8.744] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.6] [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: 11/14/2022] Open
Abstract
During development, postmitotic neurons migrate from germinal regions into the cortical plate (cp), where lamination occurs. In rats, GABA is transiently expressed in the cp, near target destinations for migrating neurons. In vitro GABA stimulates neuronal motility, suggesting cp cells release GABA, which acts as a chemoattractant during corticogenesis. Pharmacological studies indicate GABA stimulates migration via GABA(B)-receptor (GABA(B)-R) activation. Using immunohistochemistry, RT-PCR and Western blotting, we examined embryonic cortical cell expression of GABA(B)-Rs in vivo. At E17, GABA(B)-R1(+) cells were identified in the ventricular zone (vz) and cp. RT-PCR and Western blotting demonstrated the presence of GABA(B)-R1a and GABA(B)-R1b mRNA and proteins. Using immuno- cytochemistry, GABA(B)-R expression was examined in vz and cp cell dissociates before and after migration to GABA in an in vitro chemotaxis assay. GABA-induced migration resulted in an increase of GABA(B)-R(+) cells in the migrated population. While <20% of each starting dissociate was GABA(B)-R(+), >70% of migrated cells were immunopositive. We used a microchemotaxis assay to analyze cp cell release of diffusible chemotropic factor(s). In vitro, cp dissociates induced vz cell migration in a cell density-dependent manner that was blocked by micromolar saclofen (a GABA(B)-R antagonist). HPLC demonstrated cp cells release micromolar levels of GABA and taurine in several hours. Micromolar levels of both molecules stimulated cell migration that was blocked by micromolar saclofen. Thus, migratory cortical cells express GABA(B)-Rs, cp cells release GABA and taurine, and both molecules stimulate cortical cell movement. Together these findings suggest GABA and/or taurine act as chemoattractants for neurons during rat cortical histogenesis via mechanisms involving GABA(B)-Rs.
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Affiliation(s)
- T N Behar
- Laboratory of Neurophysiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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Abstract
[structure: see text]. The important biological secondary messenger NO can be generated from exogenous nitrovasodilators and NO donors. Nitrate esters are nitrovasodilators and NO mimetics, believed to be biotransformed to NO in vivo. On the basis of a mechanistic hypothesis, nitrates have been synthesized that release NO at significant rates in neutral aqueous solution in the presence only of added thiol. The novel masked beta-mercaptonitrates reported (SS-nitrates), provide information on possible sulfhydryl-dependent biotransformation mechanisms for nitrates in clinical use.
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Affiliation(s)
- S I Zavorin
- Department of Chemistry, Queen's University, Kingston, Ontario K7L 3N6, Canada
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Aguirre-Muñoz A, Buddemeier RW, Camacho-Ibar V, Carriquiry JD, Ibarra-Obando SE, Massey BW, Smith SV, Wulff F. Sustainability of coastal resource use in San Quintin, Mexico. Ambio 2001; 30:142-149. [PMID: 11436661 DOI: 10.1579/0044-7447-30.3.142] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
San Quintin, Mexico, provides a useful site for integrated analyses of material fluxes and socioeconomic constraints in a geographically isolated system. Natural resource utilization on the land is dominated by groundwater exploitation for cultivation of horticulture crops (primarily tomatoes). Irrigation exceeds water recharge minus export by a factor of 6. Resource utilization in the bay is dominated by oyster culture; food for the oysters is provided by tidal exchange of bay and ocean water. Consideration of oyster respiration and system respiration suggests that the present level of aquaculture is about 40% of the sustainable level. A "physical unsustainability index" (PhUI) was developed to measure the proportional departure of utilization of the most limiting resource for sustainability: 6 on land; 0.4 in the bay. Based on PhUI and measures of economic development, we conclude that aquaculture is more viable than agriculture.
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Affiliation(s)
- A Aguirre-Muñoz
- Kansas Geological Survey, University of Kansas, 1930 Constant Avenue, Campus West, Lawrence, Kansas 66047-3720, USA.
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Maric D, Liu QY, Maric I, Chaudry S, Chang YH, Smith SV, Sieghart W, Fritschy JM, Barker JL. GABA expression dominates neuronal lineage progression in the embryonic rat neocortex and facilitates neurite outgrowth via GABA(A) autoreceptor/Cl- channels. J Neurosci 2001; 21:2343-60. [PMID: 11264309 PMCID: PMC6762405] [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] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023] Open
Abstract
GABA emerges as a trophic signal during rat neocortical development in which it modulates proliferation of neuronal progenitors in the ventricular/subventricular zone (VZ/SVZ) and mediates radial migration of neurons from the VZ/SVZ to the cortical plate/subplate (CP/SP) region. In this study we investigated the role of GABA in the earliest phases of neuronal differentiation in the CP/SP. GABAergic-signaling components emerging during neuronal lineage progression were comprehensively characterized using flow cytometry and immunophenotyping together with physiological indicator dyes. During migration from the VZ/SVZ to the CP/SP, differentiating cortical neurons became predominantly GABAergic, and their dominant GABA(A) receptor subunit expression pattern changed from alpha4beta1gamma1 to alpha3beta3gamma2gamma3 coincident with an increasing potency of GABA on GABA(A) receptor-mediated depolarization. GABA(A) autoreceptor/Cl(-) channel activity in cultured CP/SP neurons dominated their baseline potential and indirectly their cytosolic Ca(2+) (Ca(2+)c) levels via Ca(2+) entry through L-type Ca(2+) channels. Block of this autocrine circuit at the level of GABA synthesis, GABA(A) receptor activation, intracellular Cl(-) ion homeostasis, or L-type Ca(2+) channels attenuated neurite outgrowth in most GABAergic CP/SP neurons. In the absence of autocrine GABAergic signaling, neuritogenesis could be preserved by depolarizing cells and elevating Ca(2+)c. These results reveal a morphogenic role for GABA during embryonic neocortical neuron development that involves GABA(A) autoreceptors and L-type Ca(2+) channels.
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Affiliation(s)
- D Maric
- Laboratory of Neurophysiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Levine MH, Smith SV. Starting points: state and community partnerships for young children. Future Child 2001; 11:142-149. [PMID: 11712451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Affiliation(s)
- M H Levine
- Mailman School of Public Health, Columbia University, USA
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Smith SV, Koley AP, Dai R, Robinson RC, Leong H, Markowitz A, Friedman FK. Conformational modulation of human cytochrome P450 2E1 by ethanol and other substrates: a CO flash photolysis study. Biochemistry 2000; 39:5731-7. [PMID: 10801323 DOI: 10.1021/bi000129l] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [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: 11/28/2022]
Abstract
The alcohol-inducible cytochrome P450 2E1 is a major human hepatic P450 which metabolizes a broad array of endogenous and exogenous compounds, including ethanol, low-molecular weight toxins, and fatty acids. Several substrates are known to stabilize this P450 and inhibit its cellular degradation. Furthermore, ethanol is a known modulator of P450 2E1 substrate metabolism. We examined the CO binding kinetics of P450 2E1 after laser flash photolysis of the heme-CO bond, to probe the effects of ethanol and other substrates on protein conformation and dynamics. Ethanol had an effect on the two kinetic parameters that describe CO binding: it decreased the rate of CO binding, suggesting a decrease in the protein's conformational flexibility, and increased the photosensitivity, which indicates a local effect in the active site region such as strengthening of the heme-CO bond. Other substrates decreased the CO binding rate to varying degrees. Of particular interest is the effect of arachidonic acid, which abolished photodissociation in the absence of ethanol but had no effect in the presence of ethanol. These results are consistent with a model of P450 2E1 whereby arachidonic acid binds along a long hydrophobic binding pocket and blocks exit of CO from the heme region.
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Affiliation(s)
- S V Smith
- Laboratory of Molecular Carcinogenesis, National Cancer Institute, and Bioengineering and Physical Science Program, National Institutes of Health, Bethesda, Maryland 20892, USA
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Rupon JW, Domingo SR, Smith SV, Gummadi BK, Shields H, Ballas SK, King SB, Kim-Shapiro DB. The reactions of myoglobin, normal adult hemoglobin, sickle cell hemoglobin and hemin with hydroxyurea. Biophys Chem 2000; 84:1-11. [PMID: 10723540 DOI: 10.1016/s0301-4622(99)00132-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [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]
Abstract
The kinetics of the reaction of hydroxyurea (HU) with myoglobin (Mb), hemin, sickle cell hemoglobin (HbS), and normal adult hemoglobin (HbA) were determined using optical absorption spectroscopy as a function of time, wavelength, and temperature. Each reaction appeared to follow pseudo-first order kinetics. Electron paramagnetic resonance spectroscopy (EPR) experiments indicated that each reaction produced an FeNO product. Reactions of hemin and the ferric forms of HbA, HbS, and myoglobin with HU also formed the NO adduct. The formation of methemoglobin and nitric oxide-hemoglobin from these reactions may provide further insight into the mechanism of how HU benefits sickle cell patients.
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Affiliation(s)
- J W Rupon
- Department of Chemistry, Wake Forest University, Winston-Salem, NC 27103, USA
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Omata Y, Dai R, Smith SV, Robinson RC, Friedman FK. Synthetic peptide mimics of a predicted topographical interaction surface: the cytochrome P450 2B1 recognition domain for NADPH-cytochrome P450 reductase. J Protein Chem 2000; 19:23-32. [PMID: 10882169 DOI: 10.1023/a:1007038724874] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In order to identify the cytochrome P450-binding domain for NADPH-cytochrome P450 reductase, synthetic peptide mimics of predicted surface regions of rat cytochrome P450 2B 1 were constructed and evaluated for inhibition of the P450-reductase interaction. A peptide corresponding to residues 116-134, which includes the C helix, completely inhibited reductase-mediated benzphetamine demethylation by purified P450 2B1. Replacement of Arg-125 by Glu yielded a noninhibitory peptide, suggesting that this residue significantly contributes to the reductase-P450 interaction. Additional P450 peptides were prepared which correspond to combinations of regions distant in primary sequence, but predicted to be spatially proximate. A peptide derived from segments of the C and L helices was a more potent inhibitor than peptides derived from either segment alone. This topographically designed peptide not only inhibited P450 2B1 in its purified form, but also when membrane-bound in rat liver microsomes. The peptide also inhibited microsomal aryl hydrocarbon hydroxylase, aniline hydroxylase, and erythromycin demethylase activities derived from other P450s. These results indicate that the C and L helices contribute to a reductase-binding site common to multiple P450s, and present a peptide mimic for this region that is useful for inhibition of P450-mediated microsomal activities.
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Affiliation(s)
- Y Omata
- Laboratory of Molecular Carcinogenesis, National Cancer Institute, Bethesda, Maryland 20892, USA
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Gattuso JP, Frankignoulle M, Smith SV. Measurement of community metabolism and significance in the coral reef CO2 source-sink debate. Proc Natl Acad Sci U S A 1999; 96:13017-22. [PMID: 10557265 PMCID: PMC23892 DOI: 10.1073/pnas.96.23.13017] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/1999] [Indexed: 11/18/2022] Open
Abstract
Two methods are commonly used to measure the community metabolism (primary production, respiration, and calcification) of shallow-water marine communities and infer air-sea CO2 fluxes: the pH-total alkalinity and pH-O2 techniques. The underlying assumptions of each technique are examined to assess the recent claim that the most widely used technique in coral reefs (pH-total alkalinity), may have provided spurious results in the past because of high rates of nitrification and release of phosphoric acid in the water column [Chisholm, J. R. M. & Barnes, D. J. (1998) Proc. Natl. Acad. Sci. USA 95, 6566-6569]. At least three lines of evidence suggest that this claim is not founded. First, the rate of nitrification required to explain the discrepancy between the two methods recently reported is not realistic as it is much higher than the rates measured in another reef system and greater than the highest rate measured in a marine environment. Second, fluxes of ammonium, nitrate, and phosphorus are not consistent with high rates of nitrification and release of phosphoric acid. Third, the consistency of the metabolic parameters obtained by using the two techniques is in good agreement in two sites recently investigated. The pH-total alkalinity technique therefore appears to be applicable in most coral reef systems. Consequently, the conclusion that most coral reef flats are sources of CO2 to the atmosphere does not need revision. Furthermore, we provide geochemical evidence that calcification in coral reefs, as well as in other calcifying ecosystems, is a long-term source of CO2 for the atmosphere.
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Affiliation(s)
- J P Gattuso
- Observatoire Oceanologique, UPRESA 7076 Centre National de la Recherche Scientifique-Universite Pierre-et-Marie Curie, B.P. 28, F-06234 Villefranche-sur-mer Cedex, France
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Behar TN, Scott CA, Greene CL, Wen X, Smith SV, Maric D, Liu QY, Colton CA, Barker JL. Glutamate acting at NMDA receptors stimulates embryonic cortical neuronal migration. J Neurosci 1999; 19:4449-61. [PMID: 10341246 PMCID: PMC6782619] [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] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/1999] [Revised: 03/15/1999] [Accepted: 03/22/1999] [Indexed: 02/12/2023] Open
Abstract
During cortical development, embryonic neurons migrate from germinal zones near the ventricle into the cortical plate, where they organize into layers. Mechanisms that direct neuronal migration may include molecules that act as chemoattractants. In rats, GABA, which localizes near the target destination for migrating cortical neurons, stimulates embryonic neuronal migration in vitro. In mice, glutamate is highly localized near the target destinations for migrating cortical neurons. Glutamate-induced migration of murine embryonic cortical cells was evaluated in cell dissociates and cortical slice cultures. In dissociates, the chemotropic effects of glutamate were 10-fold greater than the effects of GABA, demonstrating that for murine cortical cells, glutamate is a more potent chemoattractant than GABA. Thus, cortical chemoattractants appear to differ between species. Micromolar glutamate stimulated neuronal chemotaxis that was mimicked by microM NMDA but not by other ionotropic glutamate receptor agonists (AMPA, kainate, quisqualate). Responding cells were primarily derived from immature cortical regions [ventricular zone (vz)/subventricular zone (svz)]. Bromodeoxyuridine (BrdU) pulse labeling of cortical slices cultured in NMDA antagonists (microM MK801 or APV) revealed that antagonist exposure blocked the migration of BrdU-positive cells from the vz/svz into the cortical plate. PCR confirmed the presence of NMDA receptor expression in vz/svz cells, whereas electrophysiology and Ca2+ imaging demonstrated that vz/svz cells exhibited physiological responses to NMDA. These studies indicate that, in mice, glutamate may serve as a chemoattractant for neurons in the developing cortex, signaling cells to migrate into the cortical plate via NMDA receptor activation.
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Affiliation(s)
- T N Behar
- Laboratory of Neurophysiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA
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Barker JL, Behar T, Li YX, Liu QY, Ma W, Maric D, Maric I, Schaffner AE, Serafini R, Smith SV, Somogyi R, Vautrin JY, Wen XL, Xian H. GABAergic cells and signals in CNS development. Perspect Dev Neurobiol 1998; 5:305-22. [PMID: 9777645] [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] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
GABA is formed primarily from decarboxylation of glutamate by a family of cytosolic and membrane-bound GAD enzymes. In the adult, GAD-derived GABA sustains the vitality of the central nervous system (CNS), since blockage of GAD rapidly leads to convulsions and death. In plants, cytosolic GAD synthesizes GABA in response to hormones and environmental stress. Since decarboxylation involves protonation, secretion of GABA serves to buffer cytosolic pH in plant cells. Families of GAD and GABAA receptor/Cl- channel transcripts and encoded proteins emerge early and seemingly everywhere during CNS development, with their abundance closely paralleling neurogenesis and peaking before birth. Micromolar GABA acts at receptor/Cl-channels to depolarize progenitor cells in the cortical neuroepithelium; it also elevates their cytosolic Ca2+ (Cac2+) levels. In some way, these effects decrease proliferation. GABA directs the migration of postmitotic neuroblasts at femtomolar concentrations and stimulates their random motility at micromolar concentrations via Ca2+ signaling mechanisms. Activation of GABAA receptors by micromolar GABA may limit motility via membrane depolarization and elevated Cac2+. These results indicate that in vitro GABA can affect embryogenesis of the CNS through effects on cell proliferation and migration. As neurons differentiate postnatally, Cl(-)-dependent depolarization disappears together with GABAergic Cac2+ signals. Physiologically occurring GABAergic signals at Cl-channels exist in tonic and transient forms. Since the former are found on progenitor cells while both are present in postmitotic neurons, mechanisms to generate transients differentiate in the latter. Surprisingly, tonic and transient forms of GABAergic signaling at Cl-channels are rapidly and smoothly interconvertible and seem to be derived from online GABA synthesis in a surface-accessible compartment of the membrane.
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Affiliation(s)
- J L Barker
- Laboratory of Neurophysiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-4066, USA
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40
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Abstract
A fast and high yielding method of 188Re radiolabelling DD-3B6/22 Fab' is described. An inert atmosphere [N2(g)] and ascorbic acid was essential for preparation and storage of therapeutic levels (< or =2 GBq/mg) for up to 24 h. Immunoreactivity was greater than 75%. Pharmacokinetic studies in nu/nu mice demonstrated localisation of 188Re DD-3B6/22 Fab' was equivalent and correlated well with the behaviour observed for 99mTc DD-3B6/22 Fab' used to image ovarian cancer. Excellent stability at the target site in vivo supports the potential use of 188Re DD-3B6/22 Fab' in the therapy of ovarian cancer.
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Affiliation(s)
- P F Schmidt
- Radiopharmaceutical Division Research and Development, Australian Nuclear Science and Technology Organisation (ANSTO), Menai, NSW
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Maric D, Maric I, Smith SV, Serafini R, Hu Q, Barker JL. Potentiometric study of resting potential, contributing K+ channels and the onset of Na+ channel excitability in embryonic rat cortical cells. Eur J Neurosci 1998; 10:2532-46. [PMID: 9767384 DOI: 10.1046/j.1460-9568.1998.00284.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [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: 11/20/2022]
Abstract
Resting membrane potential (RMP), K+ channel contribution to RMP and the development of excitability were investigated in the entire population of acutely dissociated embryonic (E) rat cortical cells over E11-22 using a voltage-sensitive fluorescent indicator dye and flow cytometry. During the period of intense proliferation (E11-13), two cell subpopulations with distinct estimated RMPs were recorded: one polarized at approximately -70 mV and the other relatively less-polarized at approximately -40 mV. Ca2+o was critical in sustaining the RMP of the majority of less-polarized cells, while the well-polarized cells were characterized by membrane potentials exhibiting a approximately Nernstian relationship between RMP and [K+]o. Analysis of these two subpopulations revealed that > 80% of less-polarized cells were proliferative, while > 90% of well-polarized cells were postmitotic. Throughout embryonic development, the disappearance of Ca2+o-sensitive, less-polarized cells correlated with the disappearance of the proliferating population, while the appearance of the K+o-sensitive, well-polarized population correlated with the appearance of terminally postmitotic neurons, immuno-identified as BrdU-, tetanus toxin+ cells. Differentiating neurons were estimated to contain increased K+i relative to less-polarized cells, coinciding with the developmental expression of Cs+/Ba2+-sensitive and Ca2+-dependent K+ channels. Both K+ channels contributed to the RMP of well-polarized cells, which became more negative toward the end of neurogenesis. Depolarizing effects of veratridine, first observed at E11, progressively changed from Ca2+o-dependent and tetrodotoxin-insensitive to Na+o-dependent and tetrodotoxin-sensitive response by E18. The results reveal a dynamic development of RMP, contributing K+ channels and voltage-dependent Na+ channels in the developing cortex as it transforms from proliferative to primarily differentiating tissue.
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Affiliation(s)
- D Maric
- Laboratory of Neurophysiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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Smith SV, Liles DK, White GC, Brecher ME. Successful treatment of transient acquired factor X deficiency by plasmapheresis with concomitant intravenous immunoglobulin and steroid therapy. Am J Hematol 1998; 57:245-52. [PMID: 9495379 DOI: 10.1002/(sici)1096-8652(199803)57:3<245::aid-ajh13>3.0.co;2-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [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: 02/06/2023]
Abstract
Two patients with no history of previous bleeding diatheses presented with active bleeding from multiple body sites, declining hemoglobin levels, and markedly prolonged prothrombin times (PT) and activated partial thromboplastin times (aPTT) with incomplete correction on PT mix assays. Both patients demonstrated a severe deficiency of factor X (F.X) (<1%; reference range 60-150%). F.X levels and bleeding were refractory to multiple transfusions of fresh frozen plasma (FFP) in both patients. In contrast, daily therapeutic plasma exchange (PLEX) with concomitant administration of intravenous immunoglobulin (IV IgG) and steroids produced a rapid increase in F.X levels with cessation of bleeding, followed by stabilization and normalization of F.X levels and progressive correction of coagulation times. Neither patient has demonstrated a recurrence of the bleeding tendency following discontinuation of steroid therapy. These patients had transient acquired F.X deficiency, a rare coagulopathy, which can result in a lethal bleeding diathesis. An IgG inhibitor that selectively inhibited F.X activation in Russell's viper venom or tissue factor/F.VIIa assays was demonstrated in one patient's pretreatment plasma. Previous treatment of hemorrhage in transient acquired F.X deficiency has been prothrombin complex and/or activated clotting concentrates, which can be associated with transient hypercoagulable states. This is the first reported use of PLEX in transient acquired F.X deficiency. PLEX is safe, efficacious, and rapidly restores hemostasis in this rare acquired bleeding disorder.
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Affiliation(s)
- S V Smith
- Department of Pathology and Laboratory Medicine, University of North Carolina Hospitals, Chapel Hill 27599-7525, USA
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Abstract
We report the preliminary results from radiolabeling of a chelate-conjugated antibody with 166Ho produced from the beta(-)-decay of 166Dy. Ho-166 was separated from mg quantities of Dy target by reverse phase ion-exchange chromatography employing a cation exchange HPLC column and 0.085 M alpha-HIBA at pH = 4.3 as eluent. Evaporation to dryness of 166Ho fraction (up to 25 mL) and thermal decomposition of alpha-HIBA yielded 166Ho in a dry state which was then solubilized in 0.5 mL of 0.1 M HCl. Subsequent radiolabeling of CHX-B-DTPA conjugated 135-14 monoclonal antibodies with purified 166 Ho was readily achieved with approximately 80% efficiency and with a specific activity of 3-4 mCi of 166Ho per mg of protein. 166Ho-antibody conjugates are stable with regards to transferrin challenge for a period of 50 h. Further, it was shown that any Fe3+ ions present in alpha-HIBA as an impurity interfere with the labeling.
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Affiliation(s)
- E Dadachova
- Nuclear Medicine Group, Oak Ridge National Laboratory (ORNL), TN 37831-6229, USA
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Sallah S, Smith SV, Lony LC, Woodard P, Schmitz JL, Folds JD. Gamma/delta T-cell hepatosplenic lymphoma: review of the literature, diagnosis by flow cytometry and concomitant autoimmune hemolytic anemia. Ann Hematol 1997; 74:139-42. [PMID: 9111428 DOI: 10.1007/s002770050272] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [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: 02/04/2023]
Abstract
Hepatosplenic gamma/delta T-cell lymphoma is recognized as a subset of peripheral T-cell lymphoma in the REAL classification. Histologically these tumors are characterized by a mixture of small to medium-sized atypical lymphocytes. To date, approximately 15 cases of hepatosplenic gamma delta T-cell lymphoma have been reported. Affected individuals are usually young adults with a median age of 34 years. Patients commonly present with B symptoms and hepatosplenomegaly, but an absence of lymphadenopathy. The disease follows an aggressive course with median survival of 12-14 months and poor response to combination chemotherapy agents. Occasionally, the occurrence of frank blast transformation constitutes a terminal event for the patient. Although cytopenias are relatively common, nonimmune hemolytic anemia has been reported in one patient only. This is the first report of autoimmune hemolytic anemia associated with hepatosplenic gamma delta T-cell lymphoma.
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MESH Headings
- Adult
- Anemia, Hemolytic, Autoimmune/complications
- Biopsy
- Bone Marrow/pathology
- Bone Marrow Cells
- Flow Cytometry
- Humans
- Immunohistochemistry
- Liver Neoplasms
- Lymphocyte Count
- Lymphoma, T-Cell, Peripheral/complications
- Lymphoma, T-Cell, Peripheral/diagnosis
- Lymphoma, T-Cell, Peripheral/immunology
- Male
- Receptors, Antigen, T-Cell, alpha-beta/analysis
- Splenic Neoplasms
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Affiliation(s)
- S Sallah
- Department of Medicine, University of North Carolina at Chapel Hill, 27599-7305, USA
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Milner CM, Smith SV, Carrillo MB, Taylor GL, Hollinshead M, Campbell RD. Identification of a sialidase encoded in the human major histocompatibility complex. J Biol Chem 1997; 272:4549-58. [PMID: 9020182 DOI: 10.1074/jbc.272.7.4549] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.0] [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: 02/03/2023] Open
Abstract
Mammalian sialidases are important in modulating the sialic acid content of cell-surface and intracellular glycoproteins. However, the full extent of this enzyme family and the physical and biochemical properties of its individual members are unclear. We have identified a novel gene, G9, in the human major histocompatibility complex (MHC), that encodes a 415-amino acid protein sharing 21-28% sequence identity with the bacterial sialidases and containing three copies of the Asp-block motif characteristic of these enzymes. The level of sequence identity between human G9 and a cytosolic sialidase identified in rat and hamster (28-29%) is much less than would be expected for analogous proteins in these species, suggesting that G9 is distinct from the cytosolic enzyme. Expression of G9 in insect cells has confirmed that it encodes a sialidase, which shows optimal activity at pH 4.6, but appears to have limited substrate specificity. The G9 protein carries an N-terminal signal sequence and immunofluorescence staining of COS7 cells expressing recombinant G9 shows localization of this sialidase exclusively to the endoplasmic reticulum. The location of the G9 gene, within the human MHC, corresponds to that of the murine Neu-1 locus, suggesting that these are analogous genes. One of the functions attributed to Neu-1 is the up-regulation of sialidase activity during T cell activation.
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Affiliation(s)
- C M Milner
- MRC Immunochemistry Unit, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom
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Abstract
Electrospray ionization mass spectrometry (ESI-MS) has been used to examine the Fab, F(ab')2 and deglycosylated Fc fragments obtained from the murine IgG1 B72.3 monoclonal antibody (MAb) by digestion with the sulfhydryl protease papain, in an attempt to determine the sites of cleavage and thus to clarify the mode of action of this enzyme on MAbs. ESI analysis of the Fab and F(ab')2 subunits indicated that the predominant site of papain cleavage occurred at C221 of the B72.3 MAb heavy chain. Reduction of the intra- and interchain disulfide bridges of these fragments by 1,4-dithiothreitol and subsequent electrospray analysis showed a loss of C221 from the C-terminal end of the Fd subunit. ESI analysis of the cleaved Fab fragment indicated that there was an apparent loss of amino acid residues from this fragment. Edman sequencing of the cleaved subunit revealed an intact light chain and the loss of QVQ from the N-terminal of the Fd subunit. Reduction of this subunit gave a Fd fragment approximately 32 Da greater than the predicted mass, which we have attributed to oxidation of the heavy chain methionine residues (M81 and M136). Removal of the carbohydrate portion from the Fc fragment by N-glycosidase F indicated that papain cleavage had occurred at C223 of the B72.3 MAb heavy chain. In addition, it was observed that the C-terminal lysine residue (K438) was absent from the deglycosylated Fc fragment, presumably due to carboxypeptidase B activity that occurs during the in vivo production of the B72.3 MAb in murine hosts. These data clearly illustrate the power of ESI-MS for determining small changes in mass on large proteins as well as providing a rapid and sensitive technique for assessing MAb fragments prior to use in radioimaging or radiotherapy.
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Affiliation(s)
- K L Bennett
- Department of Chemistry, University of Wollongong, NSW, Australia
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Smith SV, Lumeng L, Read MS, Parise LV, Reddick RL, Sigman JL, Boudignon-Proudhon C, Smith JS, Li TK, Brinkhous KM. Characterization of a new hereditary thrombopathy in a closed colony of Wistar rats. J Lab Clin Med 1996; 128:601-11. [PMID: 8960644 DOI: 10.1016/s0022-2143(96)90133-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A new hereditary thrombopathy has been identified in a closed colony of Wistar rats. A simple and reproducible cuticle bleeding time test was developed as a rapid screening procedure for the bleeding diathesis. Affected animals exhibit markedly prolonged bleeding times and complete absence of platelet aggregation either with adenosine diphosphate (ADP) or with thrombin. Inheritance data suggest an autosomal dominant inheritance pattern with variable penetrance. Coagulation tests, platelet counts, plasma von Willebrand factor (vWF) activity, and clot retraction are within normal limits in thrombopathic animals. GPIb-dependent botrocetin-induced platelet agglutination was present in washed thrombopathic rat platelets. No discernible abnormality of intraplatelet organelles or granules was seen by transmission electron microscopy of thrombopathic platelets. A qualitative morphologic assessment of intraplatelet fibrinogen in thrombopathic rat platelets showed no discernible difference as compared with control rat platelets. Thrombopathic rat platelets exhibit decreased glycoprotein IIb/IIIa (GPIIb/IIIa) antigen by flow cytometric analysis and markedly decreased iodine 125-labeled fibrinogen binding to platelet GPIIb/IIIa after ADP activation. This rat colony demonstrates a unique thrombopathy, distinct from previously described animal thrombopathies, with some characteristics of variant Glanzmann's thrombasthenia. This animal model may provide further insight into the regulatory mechanisms and pathophysiology of platelet GPIIb/IIIa.
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Affiliation(s)
- S V Smith
- Department of Pathology, University of North Carolina at Chapel Hill, 27599-7525, USA
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Bennett KL, Smith SV, Lambrecht RM, Truscott RJ, Sheil MM. Rapid characterization of chemically-modified proteins by electrospray mass spectrometry. Bioconjug Chem 1996; 7:16-22. [PMID: 8741986 DOI: 10.1021/bc950064c] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [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: 02/01/2023]
Abstract
Electrospray mass spectrometry (ESI-MS) has been used to examine monoclonal antibodies (MAbs), antibody fragments (Fab and Fc), modified fragments, and a range of other chemically-modified proteins as part of a study aimed at establishing ESI-MS as a method for the characterization of radioimmunoconjugates. This has been approached from two angles. Firstly, ESI-MS of complexes formed between chelators and other small molecules conjugated to hen egg white lysozyme (HEL) (14 kDa) demonstrate the considerable advantages of this powerful new technique compared with existing methods for the characterization of chemically-conjugated proteins. Molecular weights can be determined rapidly to within 0.01-0.05% and with good sensitivity (10-50 pmol total), thus providing specific structural information and opening the way for ESI-MS to be applied widely for the structural characterization of radioimmunoconjugates. Secondly, the conditions for ESI-MS of intact antibodies and antibody fragments have been examined in detail, and we have shown that the addition of up to 10 biotin molecules to the 50 kDa Fab fragment can be easily detected in ESI mass spectra, thus demonstrating the potential for the characterization of modified MAb fragments and metabolites. Finally, the strengths and limitations of ESI-MS of intact antibodies are discussed, and these results indicate that it may only be possible to detect average shifts in the mass of intact antibodies following modification.
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Affiliation(s)
- K L Bennett
- Department of Chemistry, University of Wollongong, New South Wales, Australia
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