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Puius YA, Azar MM, Tsai H, Vergidis P, Harris CE, Anjan S, Barros N, Belga S, Chuang ST, Czeresnia JM, Goel S, Ince D, Luk A, Majeed A, Multani A, Obeid KM, Swaminathan N. Transplantid.net: A Pilot Crowdsourced, Living, Online Library of Resources for the Teaching and Practice of Transplant Infectious Diseases. Open Forum Infect Dis 2023; 10:ofad081. [PMID: 36861087 PMCID: PMC9969731 DOI: 10.1093/ofid/ofad081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 02/09/2023] [Indexed: 02/16/2023] Open
Abstract
The field of transplant infectious diseases is rapidly evolving, presenting a challenge for clinical practice and trainee education. Here we describe the construction of transplantid.net, a free online library, crowdsourced and continuously updated for the dual purpose of point-of-care evidence-based management and teaching.
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Affiliation(s)
- Yoram A Puius
- Correspondence: Yoram A. Puius, MD, PhD, Division of Infectious Diseases, Montefiore Medical Center, 111 E 210th St, Bronx, NY 10467 ()
| | - Marwan M Azar
- Section of Infectious Diseases, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Helen Tsai
- Division of Infectious Diseases, Department of Medicine, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York, USA
| | - Paschalis Vergidis
- Division of Public Health, Infectious Diseases and Occupational Medicine, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Courtney E Harris
- Division of Infectious Diseases, Brigham and Women’s Hospital, and Harvard Medical School, Boston, Massachusetts, USA
| | - Shweta Anjan
- Division of Infectious Disease, Department of Medicine, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Nicolas Barros
- Division of Infectious Diseases, Indiana University Health, Indianapolis, Indiana, USA
| | - Sara Belga
- Division of Infectious Diseases, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sally T Chuang
- Division of Infectious Diseases, Department of Medicine, University of Rochester Medical Center, Rochester, New York, USA
| | - Jonathan M Czeresnia
- Division of Infectious Diseases, Department of Medicine, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York, USA
| | - Shipra Goel
- Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Dilek Ince
- Division of Infectious Diseases, Department of Internal Medicine, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Alfred Luk
- Section of Infectious Diseases, Deming Department of Medicine, School of Medicine, Tulane University, New Orleans, Louisiana, USA
| | - Aneela Majeed
- Department of Infectious Diseases, Cleveland Clinic, Cleveland, Ohio, USA
| | - Ashrit Multani
- Division of Infectious Diseases, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Karam M Obeid
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
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Miller MA, Molina KC, Gutman JA, Scherger S, Lum JM, Mossad SB, Burgess M, Cheng MP, Chuang ST, Jacobs SE, Melendez DP, Shah DP, Zimmer A, Sohail MR, Syed S, Walker RC, Poeschla EM, Abidi MZ. Mucormycosis in Hematopoietic Cell Transplant Recipients and in Patients With Hematological Malignancies in the Era of New Antifungal Agents. Open Forum Infect Dis 2020; 8:ofaa646. [PMID: 33575424 PMCID: PMC7863870 DOI: 10.1093/ofid/ofaa646] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 12/23/2020] [Indexed: 01/28/2023] Open
Abstract
Background The survival benefit of combination antifungal therapy for invasive mucormycosis (IM) in patients with hematologic malignancy (HM) and hematopoietic cell transplant (HCT) is not well defined. Methods This multicenter, retrospective study included HM and HCT recipients with proven or probable IM between January 1, 2007 and December 31, 2017 from 10 transplant centers across North America. Results Sixty-four patients with proven (n = 47) or probable (n = 17) IM defined by 2008 European Organization for Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG) consensus definitions were included. Thirty-nine (61%) were HCT recipients (95% allogeneic). Sites of infection included rhino-orbital-cerebral (33), pulmonary (30%), disseminated (19%), gastrointestinal (3%), and cutaneous (3%). Surgical debridement was performed in 66%. Initial antifungal treatment consisted of the following: lipid formulation of amphotericin B (AmB) alone (44%), AmB + posaconazole (25%), AmB + echinocandin (13%), AmB + isavuconazole (8%), posaconazole alone (5%), and isavuconazole alone (3%). All-cause mortality at 30 days and 1 year were 38% and 66%, respectively. Initial treatment with AmB plus posaconazole or isavuconazole (n = 28) was associated with a trend toward lower treatment failure compared with AmB (n = 21) (42% vs 64%, P = .136). Conclusions Long-term survival with IM among HM and HCT populations remains poor. However, initial use of AmB + azole in conjunction with surgery may result in less treatment failure. More evidence from prospective controlled studies is needed to confirm this observation.
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Affiliation(s)
- Matthew A Miller
- Department of Pharmacy-Infectious Diseases, University of Colorado Hospital, Denver, Colorado, USA
| | - Kyle C Molina
- Department of Pharmacy-Infectious Diseases, University of Colorado Hospital, Denver, Colorado, USA
| | - Jonathan A Gutman
- Division of Hematology and Oncology, University of Colorado Denver, Denver, Colorado, USA
| | - Sias Scherger
- Division of Infectious Diseases, University of Colorado Denver, Denver, Colorado, USA
| | - Jessica M Lum
- Department of Infectious Diseases, Respiratory Institute and Transplant Center, Cleveland Clinic Foundation, Cleveland, Ohio, USA
| | - Sherif B Mossad
- Department of Infectious Diseases, Respiratory Institute and Transplant Center, Cleveland Clinic Foundation, Cleveland, Ohio, USA
| | - Mary Burgess
- Division of Infectious Diseases, University of Arkansas, Fayetteville, Arkansas, USA
| | - Matthew P Cheng
- Division of Infectious Diseases, McGill University Health Centre, Montreal, Canada.,Division of Medical Microbiology, McGill University Health Centre, Montreal, Canada
| | - Sally T Chuang
- Division of Infectious Diseases, University of Rochester, Rochester, New York, USA
| | - Samantha E Jacobs
- Division of Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Dante P Melendez
- Division of Infectious Diseases, University of Utah, Salt Lake City, Utah, USA
| | - Dimpy P Shah
- Division of Infectious Diseases, University of San Antonio, San Antonio, Texas, USA
| | - Andrea Zimmer
- Division of Infectious Diseases, University of Nebraska, Lincoln, Nebraska, USA
| | - M Rizwan Sohail
- Division of Infectious Diseases, Baylor College of Medicine, Houston, Texas, USA
| | - Sadia Syed
- Division of Infectious Diseases, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA
| | - Randall C Walker
- Division of Infectious Diseases, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA
| | - Eric M Poeschla
- Division of Infectious Diseases, University of Colorado Denver, Denver, Colorado, USA
| | - Maheen Z Abidi
- Division of Infectious Diseases, University of Colorado Denver, Denver, Colorado, USA
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Chen YC, Chang CC, Hsu WL, Chuang ST. Dairy cattle with bovine leukaemia virus RNA show significantly increased leukocyte counts. Vet J 2020; 257:105449. [PMID: 32546356 DOI: 10.1016/j.tvjl.2020.105449] [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] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 03/25/2020] [Accepted: 12/31/2019] [Indexed: 12/26/2022]
Abstract
Infection with bovine leukaemia virus (BLV), a retrovirus, causes dysfunction of the immune system and can have a marked economic impact on dairy industries due to decreased milk production and reduced lifespan in affected dairy cattle. The presence of proviral DNA has been the major diagnostic indicator of BLV infection. However in the course of BLV infection, the viral genome can be dormant, without detectable gene expression, resulting in limited impact on infected animals. At present, there is limited knowledge regarding haematological indices in dairy cattle that could indicate activation of the BLV genome and suggest reactivated BLV infection. In this study, BLV infection and BLV genome reactivation were evaluated based on the presence of BLV DNA and BLV env gene transcripts, respectively. BLV RNA transcription was confirmed. Among 93 whole blood samples obtained from asymptomatic dairy cattle, the prevalence of BLV proviral DNA and transcripts was 93.5% (n = 87/93) and 83.9% (n = 78/93), respectively. Between groups with and without BLV, the mean counts of white blood cells and lymphocytes in whole blood were significantly associated with the presence of BLV RNA (P < 0.05), but not with BLV proviral DNA. These results shed light on the activation status of the BLV genome and should be taken into account when evaluating the possible impact of BLV on cattle.
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Affiliation(s)
- Y C Chen
- Graduate Institute of Veterinary Pathobiology, College of Veterinary Medicine, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung 402, Taiwan
| | - C C Chang
- Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung 402, Taiwan
| | - W L Hsu
- Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung 402, Taiwan.
| | - S T Chuang
- Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung 402, Taiwan.
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Tomlinson SB, Sandwell S, Chuang ST, Johnson MD, Vates GE, Reagan PM. Central nervous system relapse of systemic ALK-rearranged anaplastic large cell lymphoma treated with alectinib. Leuk Res 2019; 83:106164. [PMID: 31226541 DOI: 10.1016/j.leukres.2019.05.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 05/22/2019] [Accepted: 05/27/2019] [Indexed: 12/18/2022]
Affiliation(s)
- Samuel B Tomlinson
- School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, NY, United States; Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, United States.
| | - Stephen Sandwell
- Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, United States
| | - Sally T Chuang
- Division of Infectious Diseases, Department of Medicine, University of Rochester Medical Center, Rochester, NY, United States
| | - Mahlon D Johnson
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, United States
| | - G Edward Vates
- Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, United States
| | - Patrick M Reagan
- Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, NY, United States
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Abstract
Agonist-induced airway contraction involves the generation and subsequent binding of the phosphoinositide-derived second messenger, inositol 1,4,5-trisphosphate [Ins(1,4,5)P3], to its Ca(2+)-mobilizing intracellular receptor. To the extent that regulatory cross-talk is known to exist between different signal transduction pathways, the present study examined whether activation of the adenosine 3',5'-cyclic monophosphate (cAMP)/protein kinase A (PKA) pathway induces altered binding of Ins(1,4,5)P3 to its receptor in membrane homogenates of rabbit tracheal smooth muscle (TSM). In control TSM, monophasic binding curves provided mean +/- SE values for Ins(1,4,5)P3 receptor density (Bmax) and binding affinity (Kd) amounting to 940 +/- 43 fmol/mg protein and 10.7 +/- 1.2 nM, respectively. Relative to control, binding of [3H]Ins(1,4,5)P3 was significantly reduced in paired TSM separately treated with isoproterenol, forskolin, or dibutyryl-cAMP. Ins(1,4,5)P3 binding was inhibited to a level averaging 60% of control binding by maximal concentrations of each agonist, an effect attributed to a reduction in Ins(1,4,5)P3 binding sites rather than altered ligand affinity. Collectively, these findings demonstrate that activation of the cAMP-dependent signaling pathway is associated with inhibition of Ins(1,4,5)P3 receptor binding and implicate a novel mechanism of action of beta-adrenergic agents in preventing and/or reversing airway contraction.
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Affiliation(s)
- C M Schramm
- Pediatric Pulmonary Division, University of Connecticut Health Center, Farmington 06030, USA
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Abstract
The mechanisms underlying maturational changes in agonist-mediated airway contractility remain to be identified. Since the signal transduction process coupled to airway contraction involves the Ca(2+)-mobilizing action of the second messenger, inositol 1,4,5-trisphosphate [Ins(1,4,5)P3], the present study examined 1) whether Ins(1,4,5)P3 binding to its intracellular receptor varies with age in rabbit tracheal smooth muscle (TSM), and 2) whether Ca2+ exerts a modulatory effect on Ins(1,4,5)P3 receptor binding that is age dependent. [3H]Ins(1,4,5)P3 binding was assayed in crude TSM membrane preparations isolated from 2-week-old and adult rabbits. Monophasic Scatchard plots were obtained, reflecting a single binding site, with Hill coefficients of 0.988-0.996. The mean +/- SE values for receptor density (Bmax) and binding affinity [i.e., the dissociation constant (Kd)] were similar in the adult and immature tissues, wherein Bmax = 211 +/- 6 238 +/- 60 fmol/mg protein, respectively; and Kd = 14.1 +/- 0.2 and 11.6 +/- 1.2 nM, respectively. Addition of Ca2+ (10(-8)-10(-3) M) significantly modulated Ins(1,4,5)P3 binding, with opposing maturational effects. In adult tissues, Ca2+ produced dose-dependent inhibition of Ins(1,4,5)P3 binding to 59.5% control, whereas Ins(1,4,5)P3 binding in response to Ca2+ was significantly enhanced in the 2-week-old tissues to 183% control. Collectively, these observations demonstrate that the inherent basal binding characteristics of the Ins(1,4,5)P3 receptor are similar in maturing TSM, but that Ca2+ exerts opposite modulatory actions on Ins(1,4,5)P3 receptor binding in immature and adult tissues.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- C M Schramm
- Joseph Stokes, Jr., Research Institute, Department of Pediatrics, Children's Hospital of Philadelphia, Pennsylvania 19104
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Abstract
Endothelin 1 (ET-1) is a potent vasoconstrictor peptide recently isolated from vascular endothelial cells. Because its role and mechanisms of action in regulating airway contractility remain to be identified, we examined the contractile effects of ET-1 in isolated rabbit tracheal smooth muscle (TSM) segments. In TSM under passive tension, ET-1 elicited dose-dependent contractions with a mean +/- SE -log 50% of maximal response value of 7.82 +/- 0.13 vs. a value of 5.61 +/- 0.07 -log M for acetylcholine (ACh). In TSM half-maximally contracted with ACh, however, ET-1 exerted dual and opposing contractile effects. Lower doses of ET-1 (less than or equal to 10(-9) M) produced a 74.2 +/- 16.6% decrease in active TSM tension. This relaxant response to ET-1 was associated with an accelerated accumulation of prostaglandin (PG) I2 and PGE2 and was attenuated by cyclooxygenase inhibition with indomethacin (10(-5) M). The combination of indomethacin and removal of the airway epithelium completely inhibited the TSM relaxant response to ET-1. In contrast, higher doses of ET-1 (greater than 10(-9) M) induced airway contractions that were attenuated by the Ca2+ channel blockers nifedipine (10(-5) M) and diltiazem (10(-5) M) and ablated in Ca2(+)-free buffer. Moreover, ET-1-induced TSM contractions were inhibited by the protein kinase C (PK-C) antagonists 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine, and staurosporine.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M M Grunstein
- Joseph Stokes, Jr., Research Institute, Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania 19104
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Choi WK, Chang RC, Chuang ST. Bilateral mesiodentes of identical twins--a case report. Zhonghua Ya Yi Xue Hui Za Zhi 1990; 9:116-21. [PMID: 2135995] [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: 12/30/2022]
Abstract
A pair of identical 10-year-old Chinese twins with bilateral mesiodentes of opposite orientation are presented. Three mesiodentes were conical and impacted, while the other one had erupted and was incisiform in shape. All roots of the mesiodentes were completely formed. Intrapair twin comparison showed a high degree of genetically determined concordance, with minor differences subject to environmental influences. The prevalence of mesiodens and rate of monozygotic twins in various ethnic groups are reviewed. Mirror image traits and verification of monozygocity in identical twins are also discussed.
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Affiliation(s)
- W K Choi
- Department of Dentistry, Mackay Memorial Hospital, Taipei, ROC
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Huang SY, Duh BR, Chuang ST. [Marginal leakage of glass ionomer as filling material for proximal decay in endodontic treatment]. Zhonghua Ya Yi Xue Hui Za Zhi 1989; 8:142-7. [PMID: 2486695] [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: 01/01/2023]
Abstract
The primary purpose of sealing proximal tooth defects during endodontic treatment is to prevent fluid, organic or bacterial contamination of the root canal system. At times, glass ionomers are used to restore proximal tooth defects between appointments, and after the root canal therapy. The purpose of this study was to evaluate the sealing ability of glass ionomers in teeth having proximal defects during root canal therapy. Sixty lower molars were extracted and prepared with standard endodontic access procedures. The mesial wall was then removed to mimic a proximal defect, and the tooth was filled with a glass ionomer in various thicknesses--0.8, 1.2 and 1.5 mm, respectively. After thermocycline treatment, all of the teeth were partially immersed in a 1% methylene blue dye for two weeks. During this period, the glass ionomer was directly observed to determine if any marginal leakage occurred. The glass ionomer was unacceptable if the dye penetrated to the interior wall of the pulp chamber. If not, it was classified as acceptable. The results indicated that dye penetration or leakage was least likely to occur in a 1.5 mm glass ionomer group.
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Affiliation(s)
- S Y Huang
- Department of Dentistry, Mackay Memorial Hospital, Taipei, ROC
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Chang CC, Chuang ST, Huang MC. Effects of chronic treatment with various neuromuscular blocking agents on the number and distribution of acetylcholine receptors in the rat diaphragm. J Physiol 1975; 250:161-73. [PMID: 170397 PMCID: PMC1348343 DOI: 10.1113/jphysiol.1975.sp011047] [Citation(s) in RCA: 77] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
1. Acetylcholine receptors in the end-plate and non-end-plate areas of the rat diaphragm, after treating the animal with hemicholinium-3, alpha- or beta-bungarotoxin in vivo, were studied by their specific binding of labelled alpha-bungarotoxin. 2. Subcutaneous injection of maximum tolerable doses of hemicholinium-3 (50 mug/kg) twice daily for 7 days increased the number of extrajunctional receptors along the whole length of muscle fibre, the approximate density of receptor on muscle membrane being increased from 6/mum2 in normal diaphragm to 38/mum2. Junctional receptors were also increased in number from 2-2 x 10(7) to 2-8 x 10(7) per end-plate. 3. Five days after denervation, there were approximately 153/mum2 extrajunctional receptors and the number of receptors on the end-plate was increased by 220%. 4. Intrathoracic injection of beta-bungarotoxin (50 mug/kg) also increased the density of extrajunctional receptors to approximately 104/mum2, and the number of end-plate receptors by 140% in 5 days. The neuromuscular block was extensive and prolonged. 5. [3H]Diacetyl alpha-bungarotoxin (150 mug/kg) injected into thoracic cavity caused complete neuromuscular blockade for 12 hr. At 24 hr, the synaptic transmission was restored in 80% of the junctions with less than 10% end-plate receptors freed, whereas the safety factor for transmission in normal diaphragm was 3-5. Extrajunctional receptors appeared to increase within 24 hr. This increase continued despite the restoration of neuromuscular transmission, and the receptor density at 5 days was approximately 5l/mum2. The number of junctional receptors, however, was not increased. Repeated injection of the toxin gave the same result. 6. It is concluded that the numbers of junctional and extrajunctional acetylcholine receptors are regulated in different ways, and the possible role of acetylcholine is discussed.
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Chang CC, Chen TF, Chuang ST. Influence of chronic neostigmine treatment on the number of acetylcholine receptors and the release of acetylcholine from the rat diaphragm. J Physiol 1973; 230:613-8. [PMID: 4352107 PMCID: PMC1350618 DOI: 10.1113/jphysiol.1973.sp010207] [Citation(s) in RCA: 84] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
1. Rats were treated twice daily for 7 days with neostigmine and the diaphragm was isolated for study of its acetylcholine content, release upon nerve stimulation and the number of receptors in the end-plate.2. While the content of total acetylcholine was unchanged, the release of acetylcholine on stimulation with trains of 500 pulses at 100 Hz every 20 sec was reduced by about 50%. Five days after the end of neostigmine treatment the release of acetylcholine recovered to normal.3. The total number of acetylcholine receptors in the end-plate as measured from the binding of N, O-di[(3)H]acetyl alpha-bungarotoxin was reduced from 2.1 x 10(7) to 1.2 x 10(7) per end-plate.4. The above-mentioned changes are not due to acute pharmacological effects of neostigmine, nor to an immediate effect of cholinesterase inhibition but presumably due to chronic accumulation of acetylcholine at the neuromuscular junction.
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Abstract
1. alpha-Bungarotoxin isolated from the venom of Bungarus multicinctus was acetylated with [(3)H] acetic anhydride and N-[(3)H] acetyl imidazole. Tri-N-acetyl and hexa-N-acetyl derivatives were obtained from the former, and N,O-di, N,N,O-tri and N,N,N,O-tetraacetyl derivatives from the latter reaction, respectively.2. There were parallel decreases in both neuromuscular blocking action in the phrenic nerve-diaphragm preparation of rats and depression of acetylcholine response of the rectus abdominis muscle of frogs with increased acetylation. Also, a parallel but greater decrease of toxicity in mice was found.3. N,O-Di and N,N,O-triacetyl toxins were localized mostly in the motor endplate region of the rat diaphragm, whereas a slight nonspecific binding along the whole muscle fibre in addition to the peak in the endplate region was observed with N,N,N,O-tetraacetyl and tri-N-acetyl toxins. In contrast, there was a marked nonspecific binding with hexa-N-acetyl toxin and no peak was observed at the endplate zone.4. The specific binding was saturable and irreversible. The number of toxin-receptive sites in one endplate was 1.9-2.2 x 10(7) for all of the labelled toxins irrespective of their potency.5. (+)-Tubocurarine protected effectively against the binding as well as the irreversible neuromuscular blocking effect of the toxins.6. Denervation of the rat diaphragm caused an increase of toxin-receptive sites beginning from the endplate zone at 1-2 days and then along the whole muscle fibre, reaching the maximum at about 18 days. The total receptive sites increased by about 30-fold.7. The significance of the findings is discussed and it is concluded that N,O-di and N,N,O-tri-[(3)H] acetyl alpha-bungarotoxins are specific and irreversible labelling agents for the cholinergic receptors of skeletal muscle.
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Chang CC, Wei JW, Chuang ST, Lee CY. Are the blockade of nerve conduction and depolarization of skeletal muscle induced by cobra venom due to phospholipase A, neurotoxin or cardiotoxin? Taiwan Yi Xue Hui Za Zhi 1972; 71:323-7. [PMID: 4512907] [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: 01/11/2023]
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Chang CC, Chuang ST, Lee CY, Wei JW. Role of cardiotoxin and phospholipase A in the blockade of nerve conduction and depolarization of skeletal muscle induced by cobra venom. Br J Pharmacol 1972; 44:752-64. [PMID: 5041453 PMCID: PMC1666001 DOI: 10.1111/j.1476-5381.1972.tb07313.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
1. The effects of phospholipase A (PhA), cardiotoxin (CTX) and neurotoxin (cobrotoxin) isolated from Formosan cobra (Naja naja atra) venom on conduction of the rat phrenic nerve and membrane potential of the rat diaphragm were studied.2. Phospholipase A, lysolecithin and cobrotoxin were without effect on the axonal conduction. Cardiotoxin was the only active agent in cobra venom, but it was less potent than the crude venom.3. The blocking action of cardiotoxin was markedly accelerated by the simultaneous administration of phospholipase A. However, the minimum effective concentration of cardiotoxin (100 mug/ml), was not decreased by phospholipase A. Pretreatment of the nerve with phospholipase A, followed by washout, did not alter the activity of cardiotoxin.4. Cardiotoxin (3 mug/ml) completely depolarized the membrane of superficial muscle fibres within 60 min, being 3 times more potent than the crude venom. Phospholipase A, on the other hand, needed a dose 30 times higher and a prolonged period of incubation to induce depolarization of similar extent. Cobrotoxin was without effect on membrane potentials.5. CaCl(2) (10 mM) effectively antagonized the nerve blocking as well as the depolarizing effect of the crude venom, cardiotoxin or cardiotoxin plus phospholipase A. By contrast, the slow depolarizing effect of phospholipase A was enhanced by high concentrations of calcium.6. Cardiotoxic fractions of Indian cobra venom affected both nerve conduction and diaphragm membrane potential in exactly the same way as cardiotoxin. Toxin A of the same venom was without effect.7. It is concluded that the active agent in cobra venoms either on axonal conduction or on muscle membrane is cardiotoxin. The synergistic effect of phospholipase A on cardiotoxin appears to be due to acceleration rather than potentiation of its action. The mechanism of action of cardiotoxin and its synergism by phospholipase A are discussed.
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