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Teixeira JP, Saa L, Kaucher KA, Villanueva RD, Shieh M, Baca CR, Harmon B, Owen ZJ, Mendez Majalca I, Schmidt DW, Singh N, Shaffi SK, Xu ZQ, Roha T, Mitchell JA, Demirjian S, Argyropoulos CP. Rapid implementation of an emergency on-site CKRT dialysate production system during the COVID-19 pandemic. BMC Nephrol 2023; 24:245. [PMID: 37608357 PMCID: PMC10463836 DOI: 10.1186/s12882-023-03260-9] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 06/29/2023] [Indexed: 08/24/2023] Open
Abstract
BACKGROUND On December 29, 2021, during the delta wave of the Coronavirus Disease 2019 (COVID-19) pandemic, the stock of premanufactured solutions used for continuous kidney replacement therapy (CKRT) at the University of New Mexico Hospital (UNMH) was nearly exhausted with no resupply anticipated due to supply chain disruptions. Within hours, a backup plan, devised and tested 18 months prior, to locally produce CKRT dialysate was implemented. This report describes the emergency implementation and outcomes of this on-site CKRT dialysate production system. METHODS This is a single-center retrospective case series and narrative report describing and reporting the outcomes of the implementation of an on-site CKRT dialysate production system. All adults treated with locally produced CKRT dialysate in December 2021 and January 2022 at UNMH were included. CKRT dialysate was produced locally using intermittent hemodialysis machines, hemodialysis concentrate, sterile parenteral nutrition bags, and connectors made of 3-D printed biocompatible rigid material. Outcomes analyzed included dialysate testing for composition and microbiologic contamination, CKRT prescription components, patient mortality, sequential organ failure assessment (SOFA) scores, and catheter-associated bloodstream infections (CLABSIs). RESULTS Over 13 days, 22 patients were treated with 3,645 L of locally produced dialysate with a mean dose of 20.0 mL/kg/h. Fluid sample testing at 48 h revealed appropriate electrolyte composition and endotoxin levels and bacterial colony counts at or below the lower limit of detection. No CLABSIs occurred within 7 days of exposure to locally produced dialysate. In-hospital mortality was 81.8% and 28-day mortality was 68.2%, though illness severity was high, with a mean SOFA score of 14.5. CONCLUSIONS Though producing CKRT fluid with IHD machines is not novel, this report represents the first description of the rapid and successful implementation of a backup plan for local CKRT dialysate production at a large academic medical center in the U.S. during the COVID-19 pandemic. Though conclusions are limited by the retrospective design and limited sample size of our analysis, our experience could serve as a guide for other centers navigating similar severe supply constraints in the future.
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Affiliation(s)
- J Pedro Teixeira
- Division of Nephrology, University of New Mexico (UNM) School of Medicine, MSC10-5550, 1 University of New Mexico, Albuquerque, NM, 87131, USA.
- Center for Adult Critical Care, UNM Hospital, Albuquerque, NM, USA.
- Acute Dialysis and CRRT Program, UNM Hospital, Albuquerque, NM, USA.
| | - Lisa Saa
- Department of Internal Medicine, UNM School of Medicine, Albuquerque, NM, USA
| | | | | | - Michelle Shieh
- Division of Nephrology, University of New Mexico (UNM) School of Medicine, MSC10-5550, 1 University of New Mexico, Albuquerque, NM, 87131, USA
- Center for Adult Critical Care, UNM Hospital, Albuquerque, NM, USA
| | - Crystal R Baca
- Acute Dialysis and CRRT Program, UNM Hospital, Albuquerque, NM, USA
| | - Brittany Harmon
- Acute Dialysis and CRRT Program, UNM Hospital, Albuquerque, NM, USA
| | - Zanna J Owen
- Acute Dialysis and CRRT Program, UNM Hospital, Albuquerque, NM, USA
| | | | - Darren W Schmidt
- Division of Nephrology, University of New Mexico (UNM) School of Medicine, MSC10-5550, 1 University of New Mexico, Albuquerque, NM, 87131, USA
| | - Namita Singh
- Division of Nephrology, University of New Mexico (UNM) School of Medicine, MSC10-5550, 1 University of New Mexico, Albuquerque, NM, 87131, USA
| | - Saeed K Shaffi
- Division of Nephrology, University of New Mexico (UNM) School of Medicine, MSC10-5550, 1 University of New Mexico, Albuquerque, NM, 87131, USA
| | - Zhi Q Xu
- Division of Nephrology, University of New Mexico (UNM) School of Medicine, MSC10-5550, 1 University of New Mexico, Albuquerque, NM, 87131, USA
- Acute Dialysis and CRRT Program, UNM Hospital, Albuquerque, NM, USA
| | - Thomas Roha
- Center for Adult Critical Care, UNM Hospital, Albuquerque, NM, USA
| | - Jessica A Mitchell
- Center for Adult Critical Care, UNM Hospital, Albuquerque, NM, USA
- Department of Emergency Medicine, UNM School of Medicine, Albuquerque, NM, USA
| | - Sevag Demirjian
- Department of Nephrology and Hypertension, Cleveland Clinic, Cleveland, OH, USA
| | - Christos P Argyropoulos
- Division of Nephrology, University of New Mexico (UNM) School of Medicine, MSC10-5550, 1 University of New Mexico, Albuquerque, NM, 87131, USA
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Clark PM, Chitnis N, Shieh M, Kamoun M, Johnson FB, Monos D. Novel and Haplotype Specific MicroRNAs Encoded by the Major Histocompatibility Complex. Sci Rep 2018; 8:3832. [PMID: 29497078 PMCID: PMC5832780 DOI: 10.1038/s41598-018-19427-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 12/23/2017] [Indexed: 02/06/2023] Open
Abstract
The MHC is recognized for its importance in human health and disease. However, many disease-associated variants throughout the region remain of unknown significance, residing predominantly within non-coding regions of the MHC. The characterization of non-coding RNA transcripts throughout the MHC is thus central to understanding the genetic contribution of these variants. Therefore, we characterize novel miRNA transcripts throughout the MHC by performing deep RNA sequencing of two B lymphoblastoid cell lines with completely characterized MHC haplotypes. Our analysis identifies 89 novel miRNA transcripts, 48 of which undergo Dicer-dependent biogenesis and are loaded onto the Argonaute silencing complex. Several of the identified mature miRNA and pre-miRNA transcripts are unique to specific MHC haplotypes and overlap common SNPs. Furthermore, 43 of the 89 identified novel miRNA transcripts lie within linkage disequilibrium blocks that contain a disease-associated SNP. These disease associated SNPs are associated with 65 unique disease phenotypes, suggesting that these transcripts may play a role in the etiology of numerous diseases associated with the MHC. Additional in silico analysis reveals the potential for thousands of putative pre-miRNA encoding loci within the MHC that may be expressed by different cell types and at different developmental stages.
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Affiliation(s)
- P M Clark
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - N Chitnis
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - M Shieh
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - M Kamoun
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - F B Johnson
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - D Monos
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA. .,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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Vardanyan A, Mumladze R, Badanyan A, Patrushev L, Roitman E, Dolidze D, Shieh M. C0070: Treatment of DVT: Evaluation of Safety and Efficacy. Thromb Res 2014. [DOI: 10.1016/s0049-3848(14)50213-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Shieh M, Aish B, Mohan U, Klaus S, English C, Hata S, Fox J. Enhancing Ultrasound Education through Volunteer Participation in Cardiac Screening. Ann Emerg Med 2013. [DOI: 10.1016/j.annemergmed.2013.07.208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Singh JA, Sarkin A, Shieh M, Khanna D, Terkeltaub R, Lee SJ, Kavanaugh A, Hirsch JD. Health care utilization in patients with gout. Semin Arthritis Rheum 2010; 40:501-11. [PMID: 20828793 DOI: 10.1016/j.semarthrit.2010.07.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [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] [Received: 04/25/2010] [Revised: 06/30/2010] [Accepted: 07/01/2010] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To study health care utilization patterns in patients with gout. METHODS In a gout population from primary care and rheumatology clinics in 3 U.S. metropolitan cities, we collected data on gout-related utilization (primary care, rheumatology, urgent care, emergency room, and other) in the past year. We evaluated the association of comorbidities, age, gender, gout characteristics (time since last gout attack and tophi), and gout severity ratings (mean of serum uric acid, patient-rated, and physician-rated gout severity) and with emergency/urgent care and primary care utilization using regression and correlation analyses. RESULTS Of the 296 patients who reported visiting at least 1 type of health practitioner for gout in the past year, the percentage of patients utilizing the service at least once and annual utilization rates among utilizers were as follows: primary care physician, 60%, 3.0 ± 3.4; nurse practitioner/physician assistant, 26%, 2.7 ± 2.5; rheumatologist, 51%, 3.7 ± 5.7; urgent care, 23%, 2.1 ± 2.2; emergency room, 20%, 2.0 ± 1.7; and hospitalization, 7%, 2.1 ± 1.4. Higher overall gout severity was associated with greater use of each resource type and with overall gout-related utilization. Nonemergency/nonurgent care utilization (primary care physician, nurse practitioner, physician's assistant, and rheumatologist for gout) was the strongest predictor of gout-related emergency/urgent care utilization. Patients with more comorbidities had greater gout-related primary care utilization. CONCLUSIONS Overall gout severity was associated with all types of gout-related utilization. This may help to screen high utilizers for targeted behavioral and therapeutic interventions. Having a higher number of comorbid conditions was a risk factor for higher gout-related primary care utilization.
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Henry RG, Shieh M, Okuda DT, Evangelista A, Gorno-Tempini ML, Pelletier D. Regional grey matter atrophy in clinically isolated syndromes at presentation. J Neurol Neurosurg Psychiatry 2008; 79:1236-44. [PMID: 18469033 PMCID: PMC4827711 DOI: 10.1136/jnnp.2007.134825] [Citation(s) in RCA: 185] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND The presence and degree of neuronal degeneration already existing in patients at their initial presentation with a clinically isolated syndrome suggestive of multiple sclerosis (CIS) is unclear, and whole brain or whole normalised grey matter analyses have not demonstrated significant atrophy in CIS cohorts at clinical presentation. Voxel-based analyses allow detection of regional atrophy throughout the brain and, therefore, may be sensitive to regional atrophy in CIS patients, and these changes may correspond with clinical disability. METHODS This study used a modified voxel-based morphometry (VBM) method to correct for lesion effects to analyse regional atrophy and perform voxel-wise correlations between volume and clinical metrics in 41 untreated CIS patients at presentation compared with 49 healthy controls. RESULTS The results confirmed that there was no significant difference in whole normalised grey matter volume between CIS and controls, whereas VBM showed significant areas of bilateral thalamic, hypothalamic, putamen and caudate atrophy. Voxel-wise correlations with clinical measures showed that cerebellar volumes correlated with clinical cerebellar function, nine-hole peg test scores and the Multiple Sclerosis Functional Composite (MSFC) score, and that the MSFC score was also correlated with putamen volume. Lastly, T1 lesion volumes were found to correlate with thalamic and hippocampal atrophy, suggesting a link between white matter lesions and grey matter degeneration at the earliest stages of multiple sclerosis. CONCLUSIONS Atrophy is present in CIS patients at presentations, particularly in the thalamus, and other deep grey matter structures. Furthermore, the correlations with clinical metrics suggest the importance of this atrophy to clinical status and the correlation with T1 lesion load suggests a possible role of Wallerian degeneration.
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Affiliation(s)
- R G Henry
- Department of Radiology, University of California at San Francisco, California, USA.
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Friedman JE, Zabriskie JB, Plank C, Ablashi D, Whitman J, Shahan B, Edgell R, Shieh M, Rapalino O, Zimmerman R, Sheng D. A randomized clinical trial of valacyclovir in multiple sclerosis. Mult Scler 2005; 11:286-95. [PMID: 15957509 DOI: 10.1191/1352458505ms1185oa] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [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: 11/05/2022]
Abstract
OBJECTIVE The human Herpesvirus type-6 (HHV-6) has been implicated in multiple sclerosis (MS). Valacyclovir is an antiviral agent with an excellent safety profile. A two-year placebo-controlled, double-blind study was conducted to (1) ascertain if high-dose, prolonged treatment with valacyclovir would be safe and (2) observe if valacyclovir would delay the progression of MS clinically or by magnetic resonance imaging (MRI). DESIGN/METHODS Fifty-eight patients were stratified as to severity and randomly assigned to receive valacyclovir (3000 mg/day) or placebo for a period of two years. Patients were followed clinically over the two-year period by means of the Expanded Disability Status Scale (EDSS), the Ambulation Index (AI) and brain MRI scans. Patients underwent routine lab studies every three months. Patients continued on the medication for two years unless they had a sustained progression or repeated exacerbations. RESULTS No patient discontinued the study due to side effects or toxicity. In Relative Ranking of Progression, time to first attack, attack rate, and time to withdrawal there were trends (but not statistically significant) toward drug effect over placebo in the Severe clinical category. MRI evaluation showed no significant drug effect. CONCLUSIONS Although not statistically significant, positive trends were detected for acyclovir by clinical measures, but not by MRI.
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Affiliation(s)
- J E Friedman
- Department of Neurology, New York University School of Medicine, NY, NY 10010, USA.
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Shieh M, Chen HS, Yang HY, Lin SF, Ueng CH. Tellurium-bridged manganese carbonyl clusters: synthesis and structural transformations of [Te4Mn3(CO10]-, [Te2Mn3(CO)9]2-, [Te2Mn3(CO)9]-, and [Te2Mn4(CO)12]2-. Chemistry 2001; 7:3152-8. [PMID: 11495441 DOI: 10.1002/1521-3765(20010716)7:14<3152::aid-chem3152>3.0.co;2-b] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The reactions of appropriate ratios of K2TeO3 and [Mn2(CO)10)] in superheated methanol solutions lead to a series of novel cluster anions [Te4Mn3(CO)10] (1), [Te2Mn3(CO)9]2- (2), [Te2Mn3(CO)9]- (3), and [Te2Mn4(CO)12]2- (4). When cluster 1 is treated with [Mn2(CO)10]/KOH in methanol, paramagnetic cluster 2 is formed in moderate yield. Cluster 2 is oxidized by [Cu(MeCN)4]BF4 to give the closo-cluster [Te2Mn3(CO)9]- (3), while treatment of 2 with [Mn2(CO)10]/KOH affords the closo-cluster 4. IR spectroscopy showed that cluster 1 reacted with [Mn2(CO)10] to give cluster 4 via cluster 2. Clusters 1-4 were structurally characterized by spectroscopic methods or/and X-ray analyses. The core structure of 1 can be described as two [Mn(CO)3] groups doubly bridged by two Te2 fragments in a mu2-eta2 fashion. Both [Mn(CO)3] groups are further coordinated to one [Mn(CO)4] moiety. Cluster 2 is a 49 e- species with a square-pyramidal core geometry. While cluster 3 displays a trigonal-bipyramidal metal core, cluster 4 possesses an octahedral core geometry.
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Affiliation(s)
- M Shieh
- Department of Chemistry, National Taiwan Normal University, Taipei, Republic of China.
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Cherng JJ, Lai YW, Liu YH, Peng SM, Ueng CH, Shieh M. Syntheses of chromium pentacarbonyl derivatives of arsenic(V) and antimony(V). contrasting chemical reactivity with organic halogen derivatives. Inorg Chem 2001; 40:1206-12. [PMID: 11300820 DOI: 10.1021/ic0004277] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have synthesized a new series of chromium-group 15 dihydride and hydride complexes [H(2)As(Cr(CO)(5))(2)](-) (1) and [HE(Cr(CO)(5))(3)](2)(-) (E = As, 2a; E = Sb, 2b), which represent the first examples of group 6 complexes containing E-H fragments. The contrasting chemical reactivity of 2a and 2b with organic halogen derivatives is demonstrated. The reaction of 2a with RBr (R = PhCH(2), HC triple bond CCH(2)) produces the RX addition products [(R)(Br)As(Cr(CO)(5))(2)](-) (R = PhCH(2), 3; R = C(3)H(3), 4), while the treatment of 2b with RX (RX = PhCH(2)Br or HC triple bond CCH(2)Br, CH(3)(CH(2))(5)C(O)Cl) forms the halo-substituted complexes [XSb(Cr(CO)(5))(3)](2-) (X = Br, 5; X = Cl, 6). Moreover, the dihaloantimony complexes [XX'Sb(Cr(CO)(5))(2)](-) can be obtained from the reaction of 2b with the appropriate organic halides. In this study, a series of organoarsenic and antimony chromium carbonyl complexes have been synthesized and structurally characterized and the role of the main group on the formation of the resultant complexes is also discussed.
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Affiliation(s)
- J J Cherng
- Department of Chemistry, National Taiwan Normal University, Taipei 116, Taiwan, Republic of China
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Shieh M, Chen HS, Chi HH, Ueng CH. Synthesis of an Se-Bridged triiron acyl cluster complex and the Fischer-type carbene complex derived from it: isolation of rotational isomers. Inorg Chem 2000; 39:5561-4. [PMID: 11154572 DOI: 10.1021/ic000301+] [Citation(s) in RCA: 19] [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] [Indexed: 11/30/2022]
Affiliation(s)
- M Shieh
- Department of Chemistry, National Taiwan Normal University, 88, Sec. 4, Tingchow Road, Taipei 116, Taiwan, Republic of China
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Warrington RC, Fang WD, Zhang L, Shieh M, Saier MH. L-histidinol selectively modulates daunomycin toxicity in normal and tumorigenic kidney epithelial cells. Anticancer Res 1996; 16:3629-33. [PMID: 9042233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
L-Histidinol protects normal cells from anticancer drugs while enhancing the ability of these agents to eradicate tumor cells. We now report that this attribute, previously documented in normal and tumor cells of fibroblastic or myeloid origin, extends to epithelial lines. Clonogenic cell survival assays showed that L-histidinol protected the normal Madin-Darby canine kidney (MDCK) epithelial cell line from daunomycin (DAU) toxicity, but enhanced DAU toxicity in MDCK-T1, a tumorigenic derivative of MDCK. The protection of MDCK cells from DAU by L-histidinol was improved by increasing L-histidine in the media, a condition known to diminish L-histidinol's capacity to inhibit protein synthesis. In contrast, similar conditions markedly diminished the capacity of L-histidinol to enhance DAU killing of MDCK-T1 cells. These data suggest that the differential effects of L-histidinol on DAU toxicity cannot be attributed totally to its ability to inhibit protein synthesis.
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Affiliation(s)
- R C Warrington
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Canada
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Warrington RC, Fang WD, Zhang L, Shieh M, Saier MH. Mimetics of L-histidinol which selectively modulate daunomycin toxicity in normal and tumorigenic epithelial cells. Anticancer Res 1996; 16:3635-9. [PMID: 9042234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In the accompanying publication, it was shown that L-histidinol protected the normal Madin-Darby canine kidney (MDCK) epithelial cell line from daunomycin (DAU) toxicity, but enhanced DAU toxicity in MDCK-T1, a tumorigenic derivative of MDCK. The protection of MDCK cells from DAU by L-histidinol was also shown to be independent of its ability to inhibit protein synthesis. Here, clonogenic cell survival assays show that imidazole was as effective as L-histidinol in protecting MDCK cells from DAU, but had less impact on MDCK-T1 line. Certain antieicosanoids and antihistamines mimicked, to varying extents, the DAU-modulating action of L-histidinol. These data suggest that the selective modulation of DAU toxicity by L-histidinol involves both inhibition of protein synthesis and unknown action(s) attributable to its imidazole moiety and that other pharmacological agents are modulators of anticancer drug toxicity.
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Affiliation(s)
- R C Warrington
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Canada
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Shcherban TY, Shi J, Durachko DM, Guiltinan MJ, McQueen-Mason SJ, Shieh M, Cosgrove DJ. Molecular cloning and sequence analysis of expansins--a highly conserved, multigene family of proteins that mediate cell wall extension in plants. Proc Natl Acad Sci U S A 1995; 92:9245-9. [PMID: 7568110 PMCID: PMC40961 DOI: 10.1073/pnas.92.20.9245] [Citation(s) in RCA: 135] [Impact Index Per Article: 4.7] [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: 01/26/2023] Open
Abstract
Expansins are unusual proteins discovered by virtue of their ability to mediate cell wall extension in plants. We identified cDNA clones for two cucumber expansins on the basis of peptide sequences of proteins purified from cucumber hypocotyls. The expansin cDNAs encode related proteins with signal peptides predicted to direct protein secretion to the cell wall. Northern blot analysis showed moderate transcript abundance in the growing region of the hypocotyl and no detectable transcripts in the nongrowing region. Rice and Arabidopsis expansin cDNAs were identified from collections of anonymous cDNAs (expressed sequence tags). Sequence comparisons indicate at least four distinct expansin cDNAs in rice and at least six in Arabidopsis. Expansins are highly conserved in size and sequence (60-87% amino acid sequence identity and 75-95% similarity between any pairwise comparison), and phylogenetic trees indicate that this multigene family formed before the evolutionary divergence of monocotyledons and dicotyledons. Sequence and motif analyses show no similarities to known functional domains that might account for expansin action on wall extension. A series of highly conserved tryptophans may function in expansin binding to cellulose or other glycans. The high conservation of this multigene family indicates that the mechanism by which expansins promote wall extensin tolerates little variation in protein structure.
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Affiliation(s)
- T Y Shcherban
- Department of Biology, Pennsylvania State University, University Park 16802, USA
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Abstract
Three nuclear localization signals (NLS), including an unusual Mat alpha 2-like NLS from maize (Zea mays) R, were found to compete for binding to plant nuclei. In addition, the authentic yeast Mat alpha 2 NLS, which does not function in mammals, was shown to function in plants in vivo. Our results indicate that plants possess a site at the nuclear pore complex that recognizes the three known classes of NLSs.
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Affiliation(s)
- G R Hicks
- Michigan State University-Department of Energy, Plant Research Laboratory, East Lansing 48824-1312, USA
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