1
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Wagner AM, Quandt J, Söder D, Garay‐Sarmiento M, Joseph A, Petrovskii VS, Witzdam L, Hammoor T, Steitz P, Haraszti T, Potemkin II, Kostina NY, Herrmann A, Rodriguez‐Emmenegger C. Ionic Combisomes: A New Class of Biomimetic Vesicles to Fuse with Life. Adv Sci (Weinh) 2022; 9:e2200617. [PMID: 35393756 PMCID: PMC9189634 DOI: 10.1002/advs.202200617] [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] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/03/2022] [Indexed: 06/14/2023]
Abstract
The construction of biomembranes that faithfully capture the properties and dynamic functions of cell membranes remains a challenge in the development of synthetic cells and their application. Here a new concept for synthetic cell membranes based on the self-assembly of amphiphilic comb polymers into vesicles, termed ionic combisomes (i-combisomes) is introduced. These combs consist of a polyzwitterionic backbone to which hydrophobic tails are linked by electrostatic interactions. Using a range of microscopies and molecular simulations, the self-assembly of a library of combs in water is screened. It is discovered that the hydrophobic tails form the membrane's core and force the backbone into a rod conformation with nematic-like ordering confined to the interface with water. This particular organization resulted in membranes that combine the stability of classic polymersomes with the biomimetic thickness, flexibility, and lateral mobility of liposomes. Such unparalleled matching of biophysical properties and the ability to locally reconfigure the molecular topology of its constituents enable the harboring of functional components of natural membranes and fusion with living bacteria to "hijack" their periphery. This provides an almost inexhaustible palette to design the chemical and biological makeup of the i-combisomes membrane resulting in a powerful platform for fundamental studies and technological applications.
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Affiliation(s)
- Anna M. Wagner
- DWI – Leibniz Institute for Interactive MaterialsForckenbeckstraße 50Aachen52074Germany
- Institute of Technical and Macromolecular ChemistryRWTH Aachen UniversityWorringerweg 2Aachen52074Germany
| | - Jonas Quandt
- DWI – Leibniz Institute for Interactive MaterialsForckenbeckstraße 50Aachen52074Germany
- Institute of Technical and Macromolecular ChemistryRWTH Aachen UniversityWorringerweg 2Aachen52074Germany
| | - Dominik Söder
- DWI – Leibniz Institute for Interactive MaterialsForckenbeckstraße 50Aachen52074Germany
- Institute of Technical and Macromolecular ChemistryRWTH Aachen UniversityWorringerweg 2Aachen52074Germany
| | - Manuela Garay‐Sarmiento
- DWI – Leibniz Institute for Interactive MaterialsForckenbeckstraße 50Aachen52074Germany
- Chair of BiotechnologyRWTH Aachen UniversityWorringerweg 3Aachen52074Germany
| | - Anton Joseph
- DWI – Leibniz Institute for Interactive MaterialsForckenbeckstraße 50Aachen52074Germany
- Institute of Technical and Macromolecular ChemistryRWTH Aachen UniversityWorringerweg 2Aachen52074Germany
| | - Vladislav S. Petrovskii
- Physics DepartmentLomonosov Moscow State UniversityLeninskie Gory 1–2Moscow119991Russian Federation
| | - Lena Witzdam
- DWI – Leibniz Institute for Interactive MaterialsForckenbeckstraße 50Aachen52074Germany
- Institute of Technical and Macromolecular ChemistryRWTH Aachen UniversityWorringerweg 2Aachen52074Germany
| | - Thomas Hammoor
- DWI – Leibniz Institute for Interactive MaterialsForckenbeckstraße 50Aachen52074Germany
| | - Philipp Steitz
- DWI – Leibniz Institute for Interactive MaterialsForckenbeckstraße 50Aachen52074Germany
| | - Tamás Haraszti
- DWI – Leibniz Institute for Interactive MaterialsForckenbeckstraße 50Aachen52074Germany
| | - Igor I. Potemkin
- DWI – Leibniz Institute for Interactive MaterialsForckenbeckstraße 50Aachen52074Germany
- Physics DepartmentLomonosov Moscow State UniversityLeninskie Gory 1–2Moscow119991Russian Federation
- National Research, South Ural State UniversityChelyabinsk454080Russian Federation
| | - Nina Yu. Kostina
- DWI – Leibniz Institute for Interactive MaterialsForckenbeckstraße 50Aachen52074Germany
- Institute of Technical and Macromolecular ChemistryRWTH Aachen UniversityWorringerweg 2Aachen52074Germany
| | - Andreas Herrmann
- DWI – Leibniz Institute for Interactive MaterialsForckenbeckstraße 50Aachen52074Germany
- Institute of Technical and Macromolecular ChemistryRWTH Aachen UniversityWorringerweg 2Aachen52074Germany
| | - Cesar Rodriguez‐Emmenegger
- DWI – Leibniz Institute for Interactive MaterialsForckenbeckstraße 50Aachen52074Germany
- Institute for Bioengineering of Catalonia (IBEC)Carrer de Baldiri Reixac, 10, 12Barcelona08028Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA)Passeig Lluís Companys 23Barcelona08010Spain
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Witzdam L, Meurer YL, Garay-Sarmiento M, Vorobii M, Söder D, Quandt J, Haraszti T, Rodriguez-Emmenegger C. Brush-Like Interface on Surface-Attached Hydrogels Repels Proteins and Bacteria. Macromol Biosci 2022; 22:e2200025. [PMID: 35170202 DOI: 10.1002/mabi.202200025] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/07/2022] [Indexed: 11/10/2022]
Abstract
Interfacing artificial materials with biological tissues remains a challenge. The direct contact of their surface with the biological milieu results in multiscale interactions, in which biomacromolecules adsorb and act as transducers mediating the interactions with cells and tissues. So far, only antifouling polymer brushes have been able to conceal the surface of synthetic materials. However, their complex synthesis has precluded their translation to applications. Here, we show that ultra-thin surface-attached hydrogel coatings of N-(2-hydroxypropyl) methacrylamide (HPMA) and carboxybetaine methacrylamide (CBMAA) provided the same level of protection as brushes. In spite of being readily applicable, these coatings prevented the fouling from whole blood plasma and provided a barrier to the adhesion of Gram positive and negative bacteria. The analysis of the components of the surface free energy and nanoindentation experiments revealed that the excellent antifouling properties stem from the strong surface hydrophilicity and the presence of a brush-like structure at the water interface. Moreover, these coatings could be functionalized to achieve antimicrobial activity while remaining stealth and non-cytotoxic to eukaryotic cells. Such level of performance was previously only achieved with brushes. Thus, we anticipate that this readily applicable strategy is a promising route to enhance the biocompatibility of real biomedical devices. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Lena Witzdam
- DWI - Leibniz Institute for Interactive Materials, Forckenbeckstraße 50, Aachen, 52074, Germany.,Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, Aachen, 52074, Germany
| | - Yannick L Meurer
- DWI - Leibniz Institute for Interactive Materials, Forckenbeckstraße 50, Aachen, 52074, Germany.,Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, Aachen, 52074, Germany.,Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 103, Freiburg im Breisgau, 79110, Germany
| | - Manuela Garay-Sarmiento
- DWI - Leibniz Institute for Interactive Materials, Forckenbeckstraße 50, Aachen, 52074, Germany.,Chair of Biotechnology, RWTH Aachen University, Worringerweg 3, Aachen, 52074, Germany
| | - Mariia Vorobii
- DWI - Leibniz Institute for Interactive Materials, Forckenbeckstraße 50, Aachen, 52074, Germany.,Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, Aachen, 52074, Germany
| | - Dominik Söder
- DWI - Leibniz Institute for Interactive Materials, Forckenbeckstraße 50, Aachen, 52074, Germany.,Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, Aachen, 52074, Germany
| | - Jonas Quandt
- DWI - Leibniz Institute for Interactive Materials, Forckenbeckstraße 50, Aachen, 52074, Germany.,Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, Aachen, 52074, Germany
| | - Tamás Haraszti
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, Aachen, 52074, Germany
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3
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Obstals F, Witzdam L, Garay-Sarmiento M, Kostina NY, Quandt J, Rossaint R, Singh S, Grottke O, Rodriguez-Emmenegger C. Improving Hemocompatibility: How Can Smart Surfaces Direct Blood To Fight against Thrombi. ACS Appl Mater Interfaces 2021; 13:11696-11707. [PMID: 33656864 DOI: 10.1021/acsami.1c01079] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Nature utilizes endothelium as a blood interface that perfectly controls hemostasis, preventing the uncontrolled formation of thrombi. The management of positive and negative feedback that finely tunes thrombosis and fibrinolysis is essential for human life, especially for patients who undergo extracorporeal circulation (ECC) after a severe respiratory or cardiac failure. The exposure of blood to a surface different from healthy endothelium inevitably initiates coagulation, drastically increasing the mortality rate by thromboembolic complications. In the present study, an ultrathin antifouling fibrinolytic coating capable of disintegrating thrombi in a self-regulated manner is reported. The coating system is composed of a polymer brush layer that can prevent any unspecific interaction with blood. The brushes are functionalized with a tissue plasminogen activator (tPA) to establish localized fibrinolysis that solely and exclusively is active when it is required. This interactive switching between the dormant and active state is realized through an amplification mechanism that increases (positive feedback) or restores (negative feedback) the activity of tPA depending on whether a thrombus is detected and captured or not. Thus, only a low surface density of tPA is necessary to lyse real thrombi. Our work demonstrates the first report of a coating that self-regulates its fibrinolytic activity depending on the conditions of blood.
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Affiliation(s)
- Fabian Obstals
- DWI - Leibniz-Institute for Interactive Materials e.V., Forckenbeckstraße 50, Aachen D-52074, Germany
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Forckenbeckstraße 50, Aachen D-52074, Germany
| | - Lena Witzdam
- DWI - Leibniz-Institute for Interactive Materials e.V., Forckenbeckstraße 50, Aachen D-52074, Germany
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Forckenbeckstraße 50, Aachen D-52074, Germany
| | - Manuela Garay-Sarmiento
- DWI - Leibniz-Institute for Interactive Materials e.V., Forckenbeckstraße 50, Aachen D-52074, Germany
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Forckenbeckstraße 50, Aachen D-52074, Germany
| | - Nina Yu Kostina
- DWI - Leibniz-Institute for Interactive Materials e.V., Forckenbeckstraße 50, Aachen D-52074, Germany
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Forckenbeckstraße 50, Aachen D-52074, Germany
| | - Jonas Quandt
- DWI - Leibniz-Institute for Interactive Materials e.V., Forckenbeckstraße 50, Aachen D-52074, Germany
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Forckenbeckstraße 50, Aachen D-52074, Germany
| | - Rolf Rossaint
- University Hospital Aachen, Pauwelsstraße 30, Aachen D-52074, Germany
| | - Smriti Singh
- DWI - Leibniz-Institute for Interactive Materials e.V., Forckenbeckstraße 50, Aachen D-52074, Germany
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Forckenbeckstraße 50, Aachen D-52074, Germany
| | - Oliver Grottke
- University Hospital Aachen, Pauwelsstraße 30, Aachen D-52074, Germany
| | - Cesar Rodriguez-Emmenegger
- DWI - Leibniz-Institute for Interactive Materials e.V., Forckenbeckstraße 50, Aachen D-52074, Germany
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Forckenbeckstraße 50, Aachen D-52074, Germany
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4
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Trenholme H, Hanafi A, Reed R, Sakai D, Ryan C, Barletta M, Quandt J, Knych H. Pharmacokinetics and pharmacodynamics of meperidine in healthy horses. Vet Anaesth Analg 2020. [DOI: 10.1016/j.vaa.2020.07.030] [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: 11/26/2022]
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5
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Trenholme H, Barletta M, Quandt J, Reed R, Kleine S, Hofmeister E. Effects of a 5-degree head-up incline on arterial oxygenation in anesthetized horses. Vet Anaesth Analg 2019. [DOI: 10.1016/j.vaa.2019.08.045] [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: 11/25/2022]
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6
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Barletta M, Ostenkamp SM, Taylor AC, Quandt J, Lascelles BDX, Messenger KM. The pharmacokinetics and analgesic effects of extended-release buprenorphine administered subcutaneously in healthy dogs. J Vet Pharmacol Ther 2018. [PMID: 29521421 DOI: 10.1111/jvp.12497] [Citation(s) in RCA: 3] [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] [Indexed: 01/22/2023]
Abstract
Buprenorphine is a partial μ agonist opioid used for analgesia in dogs. An extended-release formulation (ER-buprenorphine) has been shown to provide effective analgesia for 72 hr in rats and mice. Six healthy mongrel dogs were enrolled in a randomized, blinded crossover design to describe and compare the pharmacokinetics and pharmacodynamics of ER-buprenorphine administered subcutaneous at 0.2 mg/kg (ER-B) and commercially available buprenorphine for injection intravenously at 0.02 mg/kg (IV-B). After drug administration, serial blood samples were collected to measure plasma buprenorphine concentrations using liquid chromatography/mass spectrometry detection. Heart rate, respiratory rate, body temperature, sedation score, and thermal threshold latency were recorded throughout the study. Median (range) terminal half-life, time to maximum concentration, and maximum plasma concentration of ER-buprenorphine were 12.74 hr (10.43-18.84 hr), 8 hr (4-36 hr), and 5.00 ng/ml (4.29-10.98 ng/ml), respectively. Mild bradycardia, hypothermia, and inappetence were noted in both groups. Thermal threshold latency was significantly prolonged compared to baseline up to 12 hr and up to 72 hr in IV-B and ER-B, respectively. These results showed that ER-buprenorphine administered at a dose of 0.2 mg/kg resulted in prolonged and sustained plasma concentrations and antinociceptive effects up to 72 hr after drug administration.
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Affiliation(s)
- M Barletta
- Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - S M Ostenkamp
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - A C Taylor
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - J Quandt
- Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - B D X Lascelles
- Comparative Pain Research Laboratory, Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - K M Messenger
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
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7
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Hofmeister E, Barletta M, Shepard M, Brainard B, Trim C, Quandt J. Agreement among anesthesiologists regarding postoperative pain assessment in dogs. Vet Anaesth Analg 2017. [DOI: 10.1016/j.vaa.2017.09.013] [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: 11/15/2022]
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8
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Ostenkamp S, Barletta M, Quandt J, Lascelles D, Messenger K. Pharmacokinetics and pharmacodynamics of an extended-release buprenorphine formulation in dogs. Vet Anaesth Analg 2017. [DOI: 10.1016/j.vaa.2016.12.042] [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: 10/19/2022]
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9
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Barletta M, Messenger K, Hofmeister E, Quandt J. Determination of MACBAR of sevoflurane and evaluation of the effects of a ketamine constant rate infusion on sevoflurane MACBAR in sheep. Vet Anaesth Analg 2017. [DOI: 10.1016/j.vaa.2016.12.035] [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: 11/28/2022]
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10
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Proença LM, Fowler S, Kleine S, Quandt J, Mullen CO, Divers SJ. Single surgeon coelioscopic orchiectomy of desert tortoises (Gopherus agassizii) for population management. Vet Rec 2014; 175:404. [PMID: 25015072 DOI: 10.1136/vr.102421] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Orchiectomy in chelonians is a challenging procedure, especially in large species with deep and elongated testes and extensive mesorchial attachments. Single surgeon coelioscopic orchiectomy was performed in seven adult desert tortoises (Gopherus agassizii), maintained at the Desert Tortoise Conservation Center (DTCC) in Las Vegas, for population management. Surgery was successfully conducted through a bilateral prefemoral approach via sequential vascular clip ligation and radiosurgery (monopolar/bipolar). Bipolar endoscopic forceps were considered indispensable due to the extensive mesorchial attachments and their close association with the kidney. A mechanical arm was effectively used to permit orchiectomy to be completed by a single surgeon. Six of seven animals recovered from anaesthesia. Necropsy demonstrated that the death of the other was unrelated to surgical complications. One animal experienced surgically significant haemorrhage, but still made a clinical recovery. The six tortoises were returned to the DTCC and, six months postoperatively, remain healthy. This small study suggests this minimally invasive technique is an effective method for bilateral orchiectomy in desert tortoises and might be preferable in large chelonians with elongated testes.
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Affiliation(s)
- L M Proença
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, 501 DW Brooks Drive, Athens, GA 30602, USA
| | - S Fowler
- U.S. Fish and Wildlife Service, Desert Tortoise Recovery Office, 777 E. Tahquitz Canyon Way, Suite 208, Palm Springs, CA 92262, USA
| | - S Kleine
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, 501 DW Brooks Drive, Athens, GA 30602, USA
| | - J Quandt
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, 501 DW Brooks Drive, Athens, GA 30602, USA
| | - C O Mullen
- U.S. Fish and Wildlife Service, Desert Tortoise Recovery Office, 777 E. Tahquitz Canyon Way, Suite 208, Palm Springs, CA 92262, USA
| | - S J Divers
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, 501 DW Brooks Drive, Athens, GA 30602, USA
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Quandt J. [Not Available]. Salzburger Beitr Paracelsusforsch 2001; 31:44-54. [PMID: 11638965] [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: 02/22/2023]
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12
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Quandt J. [Not Available]. Salzburger Beitr Paracelsusforsch 2001; 30:88-98. [PMID: 11636676] [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: 02/22/2023]
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13
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Quandt J. [Not Available]. Salzburger Beitr Paracelsusforsch 2001; 29:35-9. [PMID: 11634273] [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: 02/21/2023]
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14
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Silverstein D, Greene C, Gregory C, Lucas S, Quandt J. Pulmonary alveolar proteinosis in a dog. J Vet Intern Med 2000; 14:546-51. [PMID: 11012120] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Affiliation(s)
- D Silverstein
- Emergency and Critical Care, University of California, Davis 95616, USA.
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15
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Polowick PL, Quandt J, Mahon JD. The ability of pea transformation technology to transfer genes into peas adapted to western Canadian growing conditions. Plant Sci 2000; 153:161-170. [PMID: 10717322 DOI: 10.1016/s0168-9452(99)00267-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Transgenic pea plants can be produced by Agrobacterium-mediated transformation of thin slices from developing embryo axes. To determine if the method is effective for different pea genotypes, seven pea breeding lines adapted to western Canadian growing conditions were tested, using three different Agrobacterium tumefaciens transformation vectors. All vectors contained the gus (uidA) gene coding for the beta-glucuronidase (GUS) protein, but with different chemical selection genes. In total, 323 transgenic plants were recovered from 39 independent transformation events. Transgenic plants were recovered from each genotype and each selection system, but not from all combinations. GUS-positive explants were obtained from seeds harvested between 24 and 31 days after flowering. The mean time from Agrobacterium treatment to planting into soil averaged 186 days. Based on the initial number of seeds used, the transformation frequency was 0.6% (i.e. six independent transgenic events per 1000 axes sliced). The inserted genes were functional and inherited in a Mendelian fashion. Although more plants were recovered by selection on chlorsulfuron, GUS activity was generally greater in plants selected on kanamycin. GUS activity in the leaves of the original plants varied, but GUS activity in the second generation was correlated with that of the original transformants.
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Affiliation(s)
- PL Polowick
- Plant Biotechnology Institute, National Research Council of Canada, 110 Gymnasium Pl., Saskatoon, Sask., Canada
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16
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Dormann M, Datla N, Hayden A, Puttick D, Quandt J. NON-DESTRUCTIVE SCREENING OF HAPLOID EMBRYOS FOR GLUFOSINATE AMMONIUM RESISTANCE FOUR WEEKS AFTER MICROSPORE TRANSFORMATION IN BRASSICA. ACTA ACUST UNITED AC 1998. [DOI: 10.17660/actahortic.1998.459.21] [Citation(s) in RCA: 5] [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: 11/17/2022]
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17
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Schlüter A, Patschkowski T, Quandt J, Selinger LB, Weidner S, Krämer M, Zhou L, Hynes MF, Priefer UB. Functional and regulatory analysis of the two copies of the fixNOQP operon of Rhizobium leguminosarum strain VF39. Mol Plant Microbe Interact 1997; 10:605-616. [PMID: 9204566 DOI: 10.1094/mpmi.1997.10.5.605] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
DNA corresponding to two copies of the Rhizobium leguminosarum bv. viciae strain VF39 fixNOQP operon coding for a putative symbiotic terminal oxidase of the heme-copper oxidase superfamily was cloned, sequenced, and genetically analyzed. The first copy is located upstream of the fixK-fixL region on plasmid pRleVF39c, whereas the second copy resides on the nodulation plasmid pRleVF39d. Insertional mutagenesis with antibiotic resistance cassettes confirmed that both copies were functional, and that the presence of at least one functional copy was required for nitrogen fixation. The deduced amino acid sequences of both fixN genes are highly similar (95% identity) and contain 15 putative transmembrane helices, suggesting that the fixN gene products are integral membrane proteins. Furthermore, six histidine residues predicted to be the ligands for a heme-copper binuclear center and a low-spin heme b are conserved in both R. leguminosarum fixN proteins. The deduced fixO and fixP gene products show characteristics of membrane-bound monoheme and diheme cytochrome c, respectively. Upstream of both fixN copies putative Fnr-consensus binding sites (anaeroboxes) were found that differ in certain base pairs. As R. leguminosarum VF39 possesses two members of the Fnr/FixK regulator family, FnrN and FixK, the possible differential regulation of both fixN copies was analyzed with fixN-gusA reporter gene fusions. Both fixN fusions were induced under free-living microaerobic conditions and in the symbiotic zone of the root nodule. Induction of the expression of fixNc and fixNd was highly reduced in a fnrN mutant background and in a fixL mutant background, whereas fixK was only marginally involved in fixN regulation. Residual expression of fixN was observed in an fnrN/fixK double mutant.
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Affiliation(s)
- A Schlüter
- Okologie des Bodens, Botanisches Institut, RWTH Aachen, Germany
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18
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Keller M, Roxlau A, Weng WM, Schmidt M, Quandt J, Niehaus K, Jording D, Arnold W, Pühler A. Molecular analysis of the Rhizobium meliloti mucR gene regulating the biosynthesis of the exopolysaccharides succinoglycan and galactoglucan. Mol Plant Microbe Interact 1995; 8:267-77. [PMID: 7756693 DOI: 10.1094/mpmi-8-0267] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The Rhizobium meliloti Tn5 mutant Rm3131, producing galactoglucan (EPS II) instead of succinoglycan (EPS I), was complemented by a 3.6-kb EcoRI-fragment of the Rhizobium meliloti genome. Sequencing of this fragment revealed six open reading frames (ORFs). The ORF found to be affected in the mutant Rm3131 codes for a putative protein of 15.7 kDa and forms a monocistronic transcriptional unit. Further genetic analysis revealed that the gene mutated in Rm3131 is identical to the previously described R. meliloti mucR gene (H. Zhan, S.B. Levery, C. C. Lee, and J.A. Leigh, 1989, Proc. Natl. Acad. Sci. USA 86:3055-3059). By hybridization it was shown that a mucR homologous gene is present in several rhizobacteria. The deduced amino acid sequence of MucR showed nearly 80% identity to the Agrobacterium tumefaciens Ros protein, a negative regulator of vir genes and necessary for succinoglycan production. MucR contains like Ros a putative zinc finger sequence of the C2H2 type. Transcriptional fusions of genes for EPS I and EPS II synthesis, the so-called exo and exp genes, with the marker gene lacZ were used to delineate the role of mucR for exo and exp gene expression. It was found that exp genes are negatively regulated by MucR on the transcriptional level, whereas a posttranscriptional regulation by MucR is assumed for exo genes. Furthermore, mucR is negatively regulating its own transcription.
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Affiliation(s)
- M Keller
- Lehrstuhl für Genetik, Fakultät für Biologie, Universität Bielefeld, Federal Republic of Germany
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19
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Abstract
A set of vector plasmids which greatly facilitate gene replacement and reverse genetics in many Gram-negative bacteria was constructed. These vectors are based on the P15A origin of replication (ori) and incorporate sacB from Bacillus subtilis, which is inducible by sucrose and is lethal when expressed in Gram-negative bacteria. The vectors also have a convenient antibiotic-resistance marker (gentamicin resistance) and the lacZ alpha system which allows blue/white selection of cloned fragments. Three different multiple cloning sites, allowing several distinct cloning and gene replacement strategies, are available in the 5' end of lacZ on different vectors. One of these cloning sites, which we synthesised, contains only a NotI-SmaI-NotI sequence; this allows access to most of the restriction sites within the cloned fragment for the purpose of insertion of various cassettes and interposons. The vectors carry the mob region from the broad-host-range plasmid RP4 and are thus mobilizable by conjugation into a wide range of Gram-negative bacteria; since they will not replicate in bacteria other than enterobacteria, they function as 'suicide' vectors. Variants of the vectors carrying the phage lambda cos site were also constructed. We have used these vectors to carry out gene replacement experiments in the fixN region of Rhizobium leguminosarum and have demonstrated that they are extremely useful in eliminating long and tedious screening procedures.
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Affiliation(s)
- J Quandt
- Department of Biological Sciences, University of Calgary, Alberta, Canada
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20
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Müller P, Keller M, Weng WM, Quandt J, Arnold W, Pühler A. Genetic analysis of the Rhizobium meliloti exoYFQ operon: ExoY is homologous to sugar transferases and ExoQ represents a transmembrane protein. Mol Plant Microbe Interact 1993; 6:55-65. [PMID: 8439670 DOI: 10.1094/mpmi-6-055] [Citation(s) in RCA: 49] [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
The nucleotide sequence of a 4.8-kb ClaI-EcoRI DNA fragment of megaplasmid 2 of Rhizobium meliloti Rm2011 involved in succinoglucan (EPS I) synthesis and nodule infection was determined. Four open reading frames (ORFs) were identified on this fragment. A mutational analysis revealed that these ORFs represent genes that were termed exoX, exoY, exoF, and exoQ. The locations of transposon insertions in these exo genes were determined at the nucleotide level. Plasmid integration mutagenesis revealed that the genes exoY, exoF, and exoQ are organized in an operon. The exoX gene running in opposite direction forms a monocistronic transcriptional unit. The exoX gene was shown to negatively influence the amount of EPS I synthesized. The exoY gene is coding for a membrane associated protein homologous to the C-terminal part of the Xanthomonas campestris glucosyltransferase GumD and the Salmonella typhimurium galactose transferase RfbP. ExoF, a probable periplasmatic protein, is nearly identical to the protein encoded by ORF1 of Rhizobium sp. strain NGR234. ExoQ is most probably a membrane associated protein as deduced by its hydrophobic structural features. All three genes of the exoYFQ operon were shown to be essential for succinoglucan synthesis and nodule infection.
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Affiliation(s)
- P Müller
- Lehrstuhl für Genetik, Fakultät fur Biologie, Universität Bielefeld, Germany
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21
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Kapp D, Niehaus K, Quandt J, Muller P, Puhler A. Cooperative Action of Rhizobium meliloti Nodulation and Infection Mutants during the Process of Forming Mixed Infected Alfalfa Nodules. Plant Cell 1990; 2:139-151. [PMID: 12354955 PMCID: PMC159871 DOI: 10.1105/tpc.2.2.139] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Alfalfa plants co-inoculated with Rhizobium meliloti nodulation (Nod-) and infection mutants deficient in exopolysaccharide production (Inf-EPS-) formed mixed infected nodules that were capable of fixing atmospheric nitrogen. The formation of infected nodules was dependent on close contact between the inoculation partners. When the partners were separated by a filter, empty Fix- nodules were formed, suggesting that infection thread formation in alfalfa is dependent on signals from the nodulation and infection genes. In mixed infected nodules, both nodulation and infection mutants colonized the plant cells and differentiated into bacteroids. The formation of bacteroids was not dependent on cell-to-cell contact between the mutants. Immunogold/silver staining revealed that the ratio of the two mutants varied considerably in colonized plant cells following mixed inoculation. The introduction of an additional nif/fix mutation into one of the inoculation partners did not abolish nitrogen fixation in mixed infected nodules. The expression of nif D::lacZ fusions additionally demonstrated that mutations in the nodulation and infection genes did not prevent the nif genes from being expressed in the mutant bacteroids.
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Affiliation(s)
- D. Kapp
- University of Bielefeld, Faculty of Biology, Department of Genetics, Postbox 8640, D-4800 Bielefeld 1, Federal Republic of Germany
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22
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Simon R, Quandt J, Klipp W. New derivatives of transposon Tn5 suitable for mobilization of replicons, generation of operon fusions and induction of genes in gram-negative bacteria. Gene X 1989; 80:161-9. [PMID: 2551782 DOI: 10.1016/0378-1119(89)90262-x] [Citation(s) in RCA: 260] [Impact Index Per Article: 7.4] [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: 01/01/2023] Open
Abstract
Three types of new variants of the broad-host-range transposon Tn5 are described. (i) Tn5-mob derivatives with the new selective resistance (R) markers GmR, SpR and TcR facilitate the efficient mobilization of replicons within a wide range of Gram-negative bacteria. (ii) Promoter probe transposons carry the promoterless reporter genes lacZ, nptII, or luc, and NmR, GmR or TcR as selective markers. These transposons can be used to generate transcriptional fusions upon insertion, thus facilitating accurate determinations of gene expression. (iii) Tn5-P-out derivatives carry the npt- or tac-promoter reading out from the transposon, and TcR, NmR or GmR genes. These variants allow the constitutive expression of downstream genes. The new Tn5 variants are available on mobilizable Escherichia coli vectors suitable as suicidal carriers for transposon mutagenesis of non-E. coli recipients and some on a phage lambda mutant to be used for transposon mutagenesis in E. coli.
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Affiliation(s)
- R Simon
- Universität Bielefeld, Fakultät für Biologie, Lehrstuhl für Genetik, F.R.G
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Quandt J, Goertchen R, Kopp EM, Sommer H. [Morphology, clinical aspects and therapy of perinatal hypoxic central nervous system damage. A pedoneuropsychiatric follow-up analysis in relation to the neurohistologic spectrum of findings]. Wien Med Wochenschr 1989; 139:288-92. [PMID: 2781808] [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: 01/02/2023]
Abstract
The histological localization and extent of ZNS-lesions caused by perinatal hypoxia has been examined in 83 cases. The neuropsychiatrical patterns of 71 in preschool and school age children after perinatal hypoxia were also investigated. Predominantly a brain stem damage with nerve cells lesions, hemorrhages and disturbance of neuroglia are found. In 1 fourth of the cases, nerve cell damage was localized in the medulla spinalis. Intramedullar hemorrhages can be observed in 10% of the cases. 41% of the cases showed subarachnoidal bleedings. Neuropsychiatrical examinations showed varying degrees of brain stem dysfunction in accordance with neurohistological findings. 1 third of the risk children demonstrated minimal brain dysfunction. In 10% an early rehabilitation of resulted in an amelioration of the ZNS-function. Special attention should be drawn to partial ZNS-disturbance-children. The problems of therapy are discussed.
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Affiliation(s)
- J Quandt
- Neuropsychiatrischen Abteilung Kreiskrankenhauses Köthen, DDR
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Hynes MF, Quandt J, O'Connell MP, Pühler A. Direct selection for curing and deletion of Rhizobium plasmids using transposons carrying the Bacillus subtilis sacB gene. Gene 1989; 78:111-20. [PMID: 2548927 DOI: 10.1016/0378-1119(89)90319-3] [Citation(s) in RCA: 87] [Impact Index Per Article: 2.5] [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: 01/01/2023]
Abstract
We have constructed derivatives of the transposon Tn5 carrying the mob site (oriT) of plasmid RP4, and an nptI-sacB-sacR cassette [Ried and Collmer, Gene 57 (1987) 239-246]. The mob site, in conjunction with the antibiotic-resistance markers carried on the transposons, allows identification of transposon inserts in cryptic plasmids by mobilisation to other strains. The sacB-sacR genes allow direct selection for the loss or curing of plasmids, because only strains which no longer contain an active sacB gene are able to grow on media containing sucrose. We have tested these transposons in four strains of Rhizobium leguminosarum and two strains of Rhizobium meliloti, and have been able to demonstrate curing of several large cryptic plasmids, and generation of large deletions in many other plasmids. This method has enabled us to show that the R. leguminosarum plasmids pRL12JI and pR1eVF39f carry auxotrophic markers, and that the plasmid pR1eVF39c carries genes which affect colony morphology.
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Affiliation(s)
- M F Hynes
- Soil Science Section, Agriculture Canada Research Station, Lethbridge, Alberta
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25
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Quandt J, Sommer H. [Affect from the biological and psychiatric viewpoint]. Z Gesamte Inn Med 1988; 43:437-9. [PMID: 2902715] [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: 01/03/2023]
Abstract
The human frame of mind is a biological and psychic problem. The man is able to influence his mood in contrast to the animal, because the human brain is functionally an open system. The questions, which result from this opinion will be demonstrated. The influence of psychopharmaca and of drugs is an actual problem of human behaviour and must be considered in the therapy of mental disturbances.
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Affiliation(s)
- J Quandt
- Akademie für Arztliche Fortbildung der DDR
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26
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Quandt J. [Current status of normocalcemic tetany]. Z Gesamte Inn Med 1983; 38:388-389. [PMID: 6415941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The author describes the actual state of research of normocalcemic tetany. Since 1959 the infusion test with ethylene diamine tetraacetic acid (EDTA) has won a central position. The EDTA test gives the possibility to classify tetanic symptoms into the circle either of hypocalcaemic or normocalcaemic syndrome. In the latter case the functional disturbance is to be treated in a form of combined therapy by tranquilizers and psychosomatic measures.
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27
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Quandt J. [Critique of so-called outsider methods in medical therapy]. Psychiatr Neurol Med Psychol (Leipz) 1982; 34:115-9. [PMID: 7089120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The manifold forms of the therapy always are of a complex nature. In pharmacological animal experiments, one can determine the parameters of the effect of a drug exactly, in humans there is often a discrepancy between these results and the actual therapy effect. Here the psychophysical mode of reaction has to be taken into account. For humans, not only the word is psychophysically effective because of its semantic property, similar effects are brought about by symbols, objects and pictures. These effects are known from the field of pre-scientific medicine and are in most cases the basis of the so-called miracle cures. Analogue effects can be seen in the field of outsider methods. They can be tolerated as long as they are not understood otherwise than as psychotherapeutic techniques with certain instrumental aids or as a psychophysical therapy with harmless substances or so-called placebos. Problems will arise when a thought process is developing.
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Quandt J. [The realization of proper care in the early diagnosis of diseases]. Z Arztl Fortbild (Jena) 1979; 73:613-6. [PMID: 506304] [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: 12/15/2022]
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29
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Sommer H, Quandt J. [Ultrastructural changes in cerebral blood vessels following prolonged administration of L-dopa to laboratory animals]. Neuropatol Pol 1976; 14:337-45. [PMID: 967310] [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: 12/25/2022]
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30
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Quandt J, Sommer H. [Morphological studies concerning the pathogenesis of cerebral endangiitis obliterans]. Neuropatol Pol 1976; 14:165-76. [PMID: 1272533] [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: 12/26/2022]
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31
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Sommer H, Quandt J. [Problems of psychopharmacotherapy with reference to ultrasonic-structural findings]. Z Arztl Fortbild (Jena) 1974; 68:1178-80. [PMID: 4456839] [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: 01/10/2023]
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32
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Sommer H, Fischer GJ, Quandt J. [The problem of side effects after a treatment with L-dopa in the Parkinson's syndrome: clinical and animal studies (author's transl)]. Folia Clin Int (Barc) 1974; 24:681-95. [PMID: 4279185] [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: 01/09/2023]
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33
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Quandt J. [Cultural-educational work in medical care]. Z Arztl Fortbild (Jena) 1974; 68:405-7. [PMID: 4409094] [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: 01/10/2023]
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34
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Quandt J, Sommer H, Glass J. [Hypertension as risk factor for cerebovascular disorders]. Z Gesamte Inn Med 1973; 28:201-5. [PMID: 4804900] [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: 01/12/2023]
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35
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Quandt J, Sommer H, Drees L. [Problems of psychopharmacologic therapy]. Z Arztl Fortbild (Jena) 1973; 67:376-82. [PMID: 4147255] [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: 01/09/2023]
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36
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Quandt J. [Problem of mental and physical unity in medical practice]. Z Arztl Fortbild (Jena) 1973; 67:307-9. [PMID: 4725565] [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: 01/12/2023]
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37
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Quandt J. [Rehabilitation in the educational status of medical specialty candidates in the fields of psychiatry and neurology]. Z Gesamte Hyg 1972; 18:70-2. [PMID: 5027012] [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: 01/13/2023]
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38
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Quandt J. [Development and perspectives of neurology and psychiatry in the German Democratic Republic]. Psychiatr Neurol Med Psychol (Leipz) 1971; 23:441-8. [PMID: 5149305] [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: 01/14/2023]
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39
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Lauschke HP, Quandt J. [Functional diagnosis of relative para thyroid insufficiency]. Psychiatr Neurol Med Psychol (Leipz) 1970; 22:10-8. [PMID: 4246368] [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: 01/09/2023]
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40
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Quandt J. [Differential diagnosis of the aging processes of the brain and its blood vessels]. Wien Klin Wochenschr 1969; 81:591-7. [PMID: 5801220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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41
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Quandt J, Sommer H. [Fever and penicillin therapy of progressive paralysis from the neuropathological viewpoint]. Dtsch Med Wochenschr 1969; 94:1486-90 passim. [PMID: 5791903 DOI: 10.1055/s-0028-1110286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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42
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Sommer H, Quandt J. [Brain tissue damage following the management of cardiazol-induced convulsions. Animal experimental contribution]. Fortschr Neurol Psychiatr Grenzgeb 1969; 37:57-76. [PMID: 5194552] [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: 01/14/2023]
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43
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Sommer H, Quandt J. [The psychiatric shock therapy from the viewpoint of experimental neuropathological studies]. Z Arztl Fortbild (Jena) 1969; 63:79-87. [PMID: 5781872] [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: 01/16/2023]
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44
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Quandt J, Sommer H. [Morphological study on the pathogenesis of cerebral endangiitis obliterans]. Fortschr Neurol Psychiatr Grenzgeb 1968; 36:661-78. [PMID: 4389990] [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: 01/10/2023]
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45
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Lange E, Quandt J, Seidel K, Walther R. [Contribution to the theses of the symposium "Socialism, scientific technological revolution and medicine"]. Psychiatr Neurol Med Psychol (Leipz) 1968; 20:151-3. [PMID: 5731866] [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: 01/16/2023]
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46
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47
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48
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Quandt J. [Pathogenetic viewpoints on cerebral thromboangitis obliterans]. Wien Med Wochenschr 1966; 116:942-3. [PMID: 5998660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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49
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Quandt J, Sommer H. [On the question of brain tissue damages after electric shock treatment. An animal experiment study]. Fortschr Neurol Psychiatr Grenzgeb 1966; 34:513-48. [PMID: 5182393] [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: 01/14/2023]
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50
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Quandt J, Sommer H. [Contribution to the pathogenesis of encephalopathia pugilistica (encephalopathy due to boxing)]. Psychiatr Neurol Med Psychol (Leipz) 1965; 17:448-51. [PMID: 5874951] [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: 01/17/2023]
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