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Schuler B, Nelson E, Owen N, Strickler E, Agrawal N, Hamid R, Grochowsky A, Morgan T, Phillips J. eP029: Response of an infant with presumed type II multiple Acyl-CoA dehydrogenase deficiency to ketone supplementation. Genet Med 2022. [DOI: 10.1016/j.gim.2022.01.067] [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: 10/18/2022] Open
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2
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Schuler B, Grochowsky A, Hatch LD, Wheeler F. eP396: Collaborative efforts between clinical genetics, cytogenetics, and neonatology improve genetic testing practices in the NICU. Genet Med 2022. [DOI: 10.1016/j.gim.2022.01.431] [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: 10/18/2022] Open
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Benton S, Rier J, Davies R, Harvey J, Schuler B, Tolerico P, Hill A, Veillet-Chowdhury M. One-stop-shop Strategy For Concurrent Diagnosis And Treatment Of Ambulatory Patient With Stable Chest Pain: Feasibility, Case Example And Workflow Using A Hybrid Angio-CT System. J Cardiovasc Comput Tomogr 2021. [DOI: 10.1016/j.jcct.2021.06.176] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Schuler B. Die Planung therapeutischer Untersuchungen bei den chronisch rheumatischen Erkrankungen. Methods Inf Med 2018. [DOI: 10.1055/s-0038-1636214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Bei der Planung eines therapeutischen Versuches bei den chronisch rheumatischen Erkrankungen bestimmt die voraussichtliche Wirkung des Medikamentes oder des Heilverfahrens, das geprüft werden soll, sowohl die Auswahl der Kranken als auch die für seine Prüfung geeigneten Methoden und die “Wahl der Beurteilungsmerkmale.Zur Prüfung dürfen nur sorgfältig abgegrenzte Krankheitsbilder in geeigneten Krankheitsstadien herangezogen werden. Sie sollen nicht nur in der Ausprägung der Symptome, sondern auch in der Prognose des Krankheitsverlaufs vergleichbar sein.Krankheitsstadien mit starkem Wechsel der Krankheitserscheinungen müssen in Kollektiven geprüft werden, deren Zusammensetzung nicht durch willkürliche Auswahl bestimmt sein darf. Auch bei chronisch sich längere Zeit hinziehenden Krankheitsbildern kann man zur Ausschaltung von Remissionen oder Spontanbesserungen auf den Gruppenvergleich nicht verzichten. Er muß aber durch eine kritische kasuistische Bearbeitung jedes Krankheitsbildes ergänzt werden.Die Kriterien einer therapeutischen Wirkung müssen so gewählt werden, daß sie die Symptome, die durch das Heilmittel verändert werden, möglichst gut zahlenmäßig erfassen. Sie müssen so häufig notiert werden, daß der Verlauf der Prüfung in allen Phasen kontrolliert werden kann.Nur wenn die Beurteilungsmerkmafe das rheumatische Krankheitsgeschehen und seinen Verlauf unter der Einwirkung des zu prüfenden Heilverfahrens richtig und vollständig erfassen, ist das Ergebnis der Prüfung stichhaltig.
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Steurer W, Schuler B, Pavliček N, Gross L, Scivetti I, Persson M, Meyer G. Toggling the Local Electric Field with an Embedded Adatom Switch. Nano Lett 2015; 15:5564-5568. [PMID: 26177363 DOI: 10.1021/acs.nanolett.5b02145] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
By means of scanning probe microscopy we demonstrate that Au(+) on NaCl films adsorbs in an embedded, slightly off-centered Cl-Cl bridge position and can be switched between two equivalent mirror-symmetric configurations using the attractive force exerted by a scanning probe tip. Density functional theory calculations demonstrate that the displacement of the Au atom from the centered position of the bridge configuration is accompanied by a large lifting of the closest Cl atom leading to significant changes in the local electrostatic field. Our findings suggest that Au(+) can be used to toggle the local electrostatic field.
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Affiliation(s)
- W Steurer
- †IBM Research-Zurich, 8803 Rüschlikon, Switzerland
| | - B Schuler
- †IBM Research-Zurich, 8803 Rüschlikon, Switzerland
| | - N Pavliček
- †IBM Research-Zurich, 8803 Rüschlikon, Switzerland
| | - L Gross
- †IBM Research-Zurich, 8803 Rüschlikon, Switzerland
| | - I Scivetti
- ‡Surface Science Research Centre and Department of Chemistry, University of Liverpool, Liverpool L69 3BX, United Kingdom
| | - M Persson
- ‡Surface Science Research Centre and Department of Chemistry, University of Liverpool, Liverpool L69 3BX, United Kingdom
| | - G Meyer
- †IBM Research-Zurich, 8803 Rüschlikon, Switzerland
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Schuler B, Tsaih S, Worthey E, Kirby A, Stevens C, Daly M, Jacob H. Identification and Investigation of Mucin 1‐Mediated Kidney Disease. FASEB J 2015. [DOI: 10.1096/fasebj.29.1_supplement.663.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Bryce Schuler
- Human and Molecular Genetics Center Medical College of WisconsinMilwaukeeWIUnited States
| | - Shring‐Wern Tsaih
- Human and Molecular Genetics Center Medical College of WisconsinMilwaukeeWIUnited States
| | - Elizabeth Worthey
- Human and Molecular Genetics Center Medical College of WisconsinMilwaukeeWIUnited States
| | - Andrew Kirby
- Broad Institute Harvard and MITCambridgeMAUnited States
| | | | - Mark Daly
- Broad Institute Harvard and MITCambridgeMAUnited States
| | - Howard Jacob
- Human and Molecular Genetics Center Medical College of WisconsinMilwaukeeWIUnited States
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Schuler B, Rieger G, Gubser M, Arras M, Gianella M, Vogel O, Jirkof P, Cesarovic N, Klohs J, Jakob P, Brock M, Gorr TA, Baum O, Hoppeler H, Samillan-Soto V, Gassmann M, Fischer JA, Born W, Vogel J. Endogenous α-calcitonin-gene-related peptide promotes exercise-induced, physiological heart hypertrophy in mice. Acta Physiol (Oxf) 2014; 211:107-21. [PMID: 24479375 DOI: 10.1111/apha.12244] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [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: 08/23/2013] [Revised: 10/10/2013] [Accepted: 01/24/2014] [Indexed: 11/29/2022]
Abstract
AIM It is unknown how the heart distinguishes various overloads, such as exercise or hypertension, causing either physiological or pathological hypertrophy. We hypothesize that alpha-calcitonin-gene-related peptide (αCGRP), known to be released from contracting skeletal muscles, is key at this remodelling. METHODS The hypertrophic effect of αCGRP was measured in vitro (cultured cardiac myocytes) and in vivo (magnetic resonance imaging) in mice. Exercise performance was assessed by determination of maximum oxygen consumption and time to exhaustion. Cardiac phenotype was defined by transcriptional analysis, cardiac histology and morphometry. Finally, we measured spontaneous activity, body fat content, blood volume, haemoglobin mass and skeletal muscle capillarization and fibre composition. RESULTS While αCGRP exposure yielded larger cultured cardiac myocytes, exercise-induced heart hypertrophy was completely abrogated by treatment with the peptide antagonist CGRP(8-37). Exercise performance was attenuated in αCGRP(-/-) mice or CGRP(8-37) treated wild-type mice but improved in animals with higher density of cardiac CGRP receptors (CLR-tg). Spontaneous activity, body fat content, blood volume, haemoglobin mass, muscle capillarization and fibre composition were unaffected, whereas heart index and ventricular myocyte volume were reduced in αCGRP(-/-) mice and elevated in CLR-tg. Transcriptional changes seen in αCGRP(-/-) (but not CLR-tg) hearts resembled maladaptive cardiac phenotype. CONCLUSIONS Alpha-calcitonin-gene-related peptide released by skeletal muscles during exercise is a hitherto unrecognized effector directing the strained heart into physiological instead of pathological adaptation. Thus, αCGRP agonists might be beneficial in heart failure patients.
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Affiliation(s)
- B. Schuler
- Institute of Veterinary Physiology; Vetsuisse Faculty University of Zürich; Zürich Switzerland
- Department of Physiology, Anatomy and Genetics; University of Oxford; Oxford UK
| | - G. Rieger
- Institute of Anatomy; University of Bern; Bern Switzerland
| | - M. Gubser
- Institute of Anatomy; University of Bern; Bern Switzerland
| | - M. Arras
- Division of Surgical Research; University Hospital Zürich; Zürich Switzerland
| | - M. Gianella
- Institute of Veterinary Physiology; Vetsuisse Faculty University of Zürich; Zürich Switzerland
| | - O. Vogel
- Institute of Veterinary Physiology; Vetsuisse Faculty University of Zürich; Zürich Switzerland
| | - P. Jirkof
- Division of Surgical Research; University Hospital Zürich; Zürich Switzerland
| | - N. Cesarovic
- Division of Surgical Research; University Hospital Zürich; Zürich Switzerland
| | - J. Klohs
- Institute for Biomedical Engineering; University of Zurich and Swiss Federal Institute of Technology; Zürich (ETHZ); Zürich Switzerland
| | - P. Jakob
- Institute of Physiology and Cardiovascular Research; University of Zürich; Zürich Switzerland
| | - M. Brock
- Division of Pulmonology; University Hospital Zürich; Zürich Switzerland
- Zürich Center for Integrative Human Physiology (ZIHP); Zürich Switzerland
| | - T. A. Gorr
- Institute of Veterinary Physiology; Vetsuisse Faculty University of Zürich; Zürich Switzerland
- Clinic IV; Division of Pediatric Hematology and Oncology; University Medical Center; Freiburg Germany
| | - O. Baum
- Institute of Anatomy; University of Bern; Bern Switzerland
| | - H. Hoppeler
- Institute of Anatomy; University of Bern; Bern Switzerland
| | - V. Samillan-Soto
- Institute of Veterinary Physiology; Vetsuisse Faculty University of Zürich; Zürich Switzerland
- Physiology Department; Medical School; Universidad Alas Peruanas; Lima Peru
| | - M. Gassmann
- Institute of Veterinary Physiology; Vetsuisse Faculty University of Zürich; Zürich Switzerland
- Zürich Center for Integrative Human Physiology (ZIHP); Zürich Switzerland
- Universidad Peruana Cayetano Heredia (UPCH); Lima Peru
| | - J. A. Fischer
- Former Research Laboratory for Calcium Metabolism; Orthopedic University Hospital Zürich; Zürich Switzerland
| | - W. Born
- Former Research Laboratory for Calcium Metabolism; Orthopedic University Hospital Zürich; Zürich Switzerland
| | - J. Vogel
- Institute of Veterinary Physiology; Vetsuisse Faculty University of Zürich; Zürich Switzerland
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Hall D, Schuler B, Schreiber M, Li L, Raugi D, Kingdon M, Smith C, Hameister C, Mokry M, Racaniello V. Human rhinovirus elicits differential cytokine response and signal transduction pathways in human macrophages as a function of viral receptor stimulation (609.2). FASEB J 2014. [DOI: 10.1096/fasebj.28.1_supplement.609.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- David Hall
- Chemistry Lawrence UniversityAppletonWIUnited States
| | - Bryce Schuler
- Chemistry Lawrence UniversityAppletonWIUnited States
| | | | - LuYuan Li
- Chemistry Lawrence UniversityAppletonWIUnited States
| | - Dana Raugi
- Chemistry Lawrence UniversityAppletonWIUnited States
| | - Megan Kingdon
- Chemistry Lawrence UniversityAppletonWIUnited States
| | - Cosonya Smith
- Chemistry Lawrence UniversityAppletonWIUnited States
| | | | - Michal Mokry
- Immunology University Medical Center Utrecht UtrechtNetherlands
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Abstract
Microfluidic mixing devices are increasingly popular tools for probing the non-equilibrium dynamics of biomolecular systems. Commonly, hydrodynamic focusing is used to reduce the length scales that limit the time of diffusive mixing in the laminar flow regime, such that even sub-millisecond dead times for triggering a reaction have been achieved. Detection of a suitable signal at different points along the channel downstream of the mixing region, corresponding to different times after mixing, then allows the kinetics of the reaction to be obtained. However, the requisite accurate conversion of the positions in the channel to times after mixing is complicated by Taylor dispersion, the combined effect of diffusion and shear flow on the dispersion of the molecules in the microfluidic device. As a result, an accurate position-to-time conversion has only been possible in the limiting regimes, i.e. for very early times, where sample diffusion can be neglected, and for very long times, where the molecules have uniformly sampled the entire channel cross-section. Here, we use detailed three-dimensional, time-dependent finite-element calculations to obtain an accurate position-to-time conversion that bridges these two limits and allows us to quantify the effects of Taylor dispersion on the time resolution of a representative mixing device optimized for single-molecule fluorescence detection. The accuracy of the calculations is confirmed by direct comparison of the calculated velocity field with dual-focus fluorescence correlation spectroscopy measurements.
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Affiliation(s)
- B Wunderlich
- Department of Biochemistry, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland.
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Schreiber MT, Schuler B, Li L, Hall DJ. Activation of the small G-protein Rac by human rhinovirus attenuates the TLR3/IFN-α axis while promoting CCL2 release in human monocyte-lineage cells. Innate Immun 2012; 19:278-89. [PMID: 23060458 DOI: 10.1177/1753425912460709] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Although rhinoviral infections, a major cause of asthma exacerbations, occur predominantly in upper airway bronchial epithelial cells, monocytic-lineage cells are implicated in establishing the inflammatory microenvironment observed during the disease. Human rhinovirus (HRV) is unique in that nearly genetically identical viruses bind either the ICAM-1 or low-density lipoprotein receptor (LDL-R). Within minutes of binding, HRV is capable of eliciting a signaling response in both epithelial cells and monocyte-derived macrophages. It is unclear whether this signaling response is important to the subsequent release of inflammatory mediators, particularly in cells not capable of supporting viral replication. We show here that the small molecular mass G-protein Rac is activated following exposure of macrophages to HRV serotypes known to be ICAM-1- and LDL-R-tropic. We demonstrate that inhibiting Rac resulted in the upregulation of TLR3 in macrophages exposed to major- and minor-group HRV, and resulted in increased release of IFN-α. Furthermore, inhibiting Rac in HRV-exposed macrophages attenuated activation of the stress kinase p38 and release of the pro-inflammatory cytokine CCL2, but inhibiting Rac did not affect release of the pro-inflammatory cytokine CCL5. These findings suggest that Rac is an important regulator in establishing the inflammatory microenvironment that is initiated in the human airway upon exposure to rhinovirus.
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11
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Hassan R, Sharon E, Schuler B, Mallory Y, Zhang J, Ling A, Pastan I. Antitumor activity of SS1P with pemetrexed and cisplatin for front-line treatment of pleural mesothelioma and utility of serum mesothelin as a marker of tumor response. J Clin Oncol 2011. [DOI: 10.1200/jco.2011.29.15_suppl.7026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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14
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15
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Schuler B, Raugi D, Wilson M, Hall DJ. Differential MAPK and cytokine responses to human rhinovirus by human macrophages is a function of receptor‐mediated signal transduction. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.524.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Schreiber M, Schuler B, Hall DJ. Differential Rac activation by major and minor group rhinovirus results in altered MAPK activation and cytokine release from human macrophages. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.882.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Abstract
This study tested the hypothesis that maximal oxygen uptake (VO(2max)) and performance increase upon altitude acclimatization at moderate altitude. Eight elite cyclists were studied at sea level, and after 1 (Day 1), 7 (Day 7), 14 (Day 14) and 21 (Day 21) days of exposure to 2340 m. Capillary blood samples were taken on these days before performing two consecutive maximal exercise trials. Acclimatization increased hemoglobin concentration and arterial oxygen content. On Day 1, VO(2max) and time to exhaustion (at 80% of sea-level maximal power output) decreased by 12.8% (P<0.05) and 25.8% (P<0.05), respectively, compared with the corresponding sea-level values. Subsequently, these parameters increased by 3.2% (P<0.05) and 6.0% (P<0.05) from Days 1 to 7, by 4.8% (P<0.05) and 5.7% (P<0.05) from Days 7 to 14, followed by 0.7% (P>0.05) and 1.4% (P>0.05) from Days 14 to 21, respectively. These data suggest that endurance athletes competing at altitudes around 2340 m should expose themselves to this altitude at least 14 days before competition.
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Affiliation(s)
- B Schuler
- Institute of Veterinary Physiology, Vetsuisse Faculty and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
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Wright MA, Schuler B, Szabo E, Grem JL. Sustained partial response of an intra-abdominal desmoid tumor treated with gemcitabine, 5-fluorouracil and leucovorin. Ann Oncol 2003; 14:659-60. [PMID: 12649120 DOI: 10.1093/annonc/mdg155] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Schuler B. Late aortic systolic pressure augmentation and increased pulse pressure in heart transplant recipients: a marker of increased peripheral vascular stiffness. Am J Hypertens 2001. [DOI: 10.1016/s0895-7061(01)01467-4] [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: 10/18/2022] Open
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Grem JL, Yee LK, Schuler B, Hamilton JM, Chen AP, Chabuk C, Grollman F, Grabenc M, Allegra CJ, Takimoto CH. N-(phosphonacetyl)-L-aspartate and calcium leucovorin modulation of fluorouracil administered by constant rate and circadian pattern of infusion over 72 hours in metastatic gastrointestinal adenocarcinoma. Ann Oncol 2001; 12:1581-7. [PMID: 11822758 DOI: 10.1023/a:1013185125186] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND We have reported that N-(phosphonacetyl)-L-aspartic acid (PALA) 1266 mg/m2 can safely be given 24 hours prior to the start of a 72-hour infusion of fluorouracil (FUra) and leucovorin (LV) at doses of 2000 and 500 mg/m2/day. Since inhibition of aspartate carbamoyltransferase (ACTase) activity was evident 4 hours post PALA, we wished to evaluate PALA given 1 hour prior to FUra. Further, we studied the toxicity and pharmacokinetics with FUra given by either fixed- or variable-rate infusion. PATIENTS AND METHODS Twenty-seven patients with gastrointestinal tract adenocarcinomas were treated with PALA 1266 mg/m2/15 min followed by a 72-hour infusion of FUra and LV (1750 & 500 mg/m2/day) given by fixed- or variable-rate (peak at 4:00 A.M.). RESULTS Clinical toxicity was similar in two consecutive cycles in 17 patients receiving fixed- and variable-rate infusion at the same FUra dose. Overall, grade 3 stomatitis and hand-foot syndrome occurred in 12% and 4% patients receiving fixed- and in 16% and 10.5% of patients receiving variable-rate infusions. Six of 24 evaluable patients (25%) had a partial response. The profile of FUra plasma levels (Cp) over a 24-hour period during fixed- and variable-rate infusions were strikingly different, but the average Cp and area under the concentration-time curves were comparable. ACTase activity was significantly decreased at 4 and 24 hours after PALA (12% and 18% of baseline; P < 0.001), but enzyme activity had recovered to 40% by 72 hours. CONCLUSIONS This regimen was active and well tolerated with similar toxicities with FUra given by either fixed- or variable rate infusion. PALA 1266 mg/m2 significantly inhibited ACTase activity for at least 24 hours.
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Affiliation(s)
- J L Grem
- NCI-Navy Medicine Branch, National Cancer Institute, National Naval Medical Center, Bethesda, Maryland 20889-5105, USA.
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Kremer W, Schuler B, Harrieder S, Geyer M, Gronwald W, Welker C, Jaenicke R, Kalbitzer HR. Solution NMR structure of the cold-shock protein from the hyperthermophilic bacterium Thermotoga maritima. Eur J Biochem 2001; 268:2527-39. [PMID: 11322871 DOI: 10.1046/j.1432-1327.2001.02127.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cold-shock proteins (Csps) are a subgroup of the cold-induced proteins preferentially expressed in bacteria and other organisms on reduction of the growth temperature below the physiological temperature. They are related to the cold-shock domain found in eukaryotes and are some of the most conserved proteins known. Their exact function is still not known, but translational regulation, possibly via RNA chaperoning, has been discussed. Here we present the structure of a hyperthermophilic member of the Csp family. The NMR solution structure of TmCsp from Thermotoga maritima, the hyperthermophilic member of this class of proteins, was solved on the basis of 1015 conformational constraints. It contains five beta strands combined in two antiparallel beta sheets making up a beta barrel structure, in which beta strands 1-4 are arranged in a Greek-key topology. The side chain of R2, which is exclusively found in thermophilic members of the Csp family, probably participates in a peripheral ion cluster involving residues D20, R2, E47 and K63, suggesting that the thermostability of TmCsp is based on the peripheral ion cluster around the side chain of R2.
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Affiliation(s)
- W Kremer
- Institut für Biophysik und physikalische Biochemie, Universität Regensburg, Germany
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Janne P, Margolis L, Means-Markwell M, O'Neil K, Linnoila R, Williams J, Schuler B, Fitzgerald W, Kaye F, Johnson B. The development of a short term in vitro culture system for bronchial biopsy specimens in patients with previously treated or suspected lung carcinoma. Lung Cancer 2000. [DOI: 10.1016/s0169-5002(00)80590-5] [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: 11/16/2022]
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Schuler B, Fürst F, Osterroth F, Steinbacher S, Huber R, Seckler R. Plasticity and steric strain in a parallel beta-helix: rational mutations in the P22 tailspike protein. Proteins 2000; 39:89-101. [PMID: 10737931] [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: 02/16/2023]
Abstract
By means of genetic screens, a great number of mutations that affect the folding and stability of the tailspike protein from Salmonella phage P22 have been identified. Temperature-sensitive folding (tsf) mutations decrease folding yields at high temperature, but hardly affect thermal stability of the native trimeric structure when assembled at low temperature. Global suppressor (su) mutations mitigate this phenotype. Virtually all of these mutations are located in the central domain of tailspike, a large parallel beta-helix. We modified tailspike by rational single amino acid replacements at three sites in order to investigate the influence of mutations of two types: (1) mutations expected to cause a tsf phenotype by increasing the side-chain volume of a core residue, and (2) mutations in a similar structural context as two of the four known su mutations, which have been suggested to stabilize folding intermediates and the native structure by the release of backbone strain, an effect well known for residues that are primarily evolved for function and not for stability or folding of the protein. Analysis of folding yields, refolding kinetics and thermal denaturation kinetics in vitro show that the tsf phenotype can indeed be produced rationally by increasing the volume of side chains in the beta-helix core. The high-resolution crystal structure of mutant T326F proves that structural rearrangements only take place in the remarkably plastic lumen of the beta-helix, leaving the arrangement of the hydrogen-bonded backbone and thus the surface of the protein unaffected. This supports the notion that changes in the stability of an intermediate, in which the beta-helix domain is largely formed, are the essential mechanism by which tsf mutations affect tailspike folding. A rational design of su mutants, on the other hand, appears to be more difficult. The exchange of two residues in the active site expected to lead to a drastic release of steric strain neither enhanced the folding properties nor the stability of tailspike. Apparently, side-chain interactions in these cases overcompensate for backbone strain, illustrating the extreme optimization of the tailspike protein for conformational stability. The result exemplifies the view arising from the statistical analysis of the distribution of backbone dihedral angles in known three-dimensional protein structures that the adoption of straight phi/psi angles other than the most favorable ones is often caused by side-chain interactions. Proteins 2000;39:89-101.
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Affiliation(s)
- B Schuler
- Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Regensburg, Germany
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24
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Schuler B, Rachel R, Seckler R. Formation of fibrous aggregates from a non-native intermediate: the isolated P22 tailspike beta-helix domain. J Biol Chem 1999; 274:18589-96. [PMID: 10373469 DOI: 10.1074/jbc.274.26.18589] [Citation(s) in RCA: 34] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the assembly pathway of the trimeric P22 tailspike protein, the protein conformation critical for the partitioning between productive folding and off-pathway aggregation is a monomeric folding intermediate. The central domain of tailspike, a large right-handed parallel beta-helix, is essentially structured in this species. We used the isolated beta-helix domain (Bhx), expressed with a hexahistidine tag, to investigate the mechanism of aggregation without the two terminal domains present in the complete protein. Although Bhx has been shown to fold reversibly at low ionic strength conditions, increased ionic strength induced aggregation with a maximum at urea concentrations corresponding to the midpoint of urea-induced folding transitions. According to size exclusion chromatography, aggregation appeared to proceed via a linear polymerization mechanism. Circular dichroism indicated a secondary structure content of the aggregates similar to that of the native state, but at the same time their tryptophan fluorescence was largely quenched. Microscopic analysis of the aggregates revealed a variety of morphologies; among others, fibrils with fine structure were observed that exhibited bright green birefringence if viewed under cross-polarized light after staining with Congo red. These observations, together with the effects of folding mutations on the aggregation process, indicate the involvement of a partially structured intermediate distinct from both unfolded and native Bhx.
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Affiliation(s)
- B Schuler
- Institut für Biophysik und Physikalische Biochemie, Genetik und Mikrobiologie, Universität Regensburg, 93040 Regensburg, Germany.
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Takimoto CH, Yee LK, Venzon DJ, Schuler B, Grollman F, Chabuk C, Hamilton JM, Chen AP, Allegra CJ, Grem JL. High inter- and intrapatient variation in 5-fluorouracil plasma concentrations during a prolonged drug infusion. Clin Cancer Res 1999; 5:1347-52. [PMID: 10389918] [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: 02/13/2023]
Abstract
The purpose of the study was to examine inter- and intrapatient variation in 5-fluorouracil (5-FU) plasma concentrations in adult cancer patients receiving a 3-day drug infusion. Fourteen patients received 1266 mg/m2 N-(phosphonacetyl)-L-aspartate (PALA) infused i.v. over 15 min on day 1, followed immediately by a loading dose of 500 mg/m2 calcium leucovorin over 30 min. Then a prolonged infusion of leucovorin at 500 mg/m2/day and 5-FU at 1750 mg/m2/day was administered as either a constant rate or as a circadian infusion over 72 h. During constant rate infusions, 5-FU concentrations within individuals varied by 1.7-fold, but no uniform time of peak or trough concentration was observed. Transformation of these data by setting the time of peak to 0 h and by expressing concentrations as the percentage of the 24-h mean value revealed a nonrandom distribution of the time from peak to trough with a median time of 12 h (P = 0.027). These transformed data were also successfully fit to a circadian cosinor function (P < 0.001). During multiple constant rate 5-FU infusions, the intrapatient variability was high; the times of peak 5-FU concentration occurred at the same approximate sampling time 43% of the time, and troughs coincided 17% of the time. No difference in clinical toxicity was observed when matched constant rate and circadian infusions of 5-FU were compared. High inter- and intrapatient variability exists in 5-FU plasma concentrations in adult cancer patients during constant rate infusions with no evidence of a consistent circadian rhythm in untransformed data.
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Affiliation(s)
- C H Takimoto
- Developmental Therapeutics Department, Medicine Branch, Division of Clinical Sciences, National Cancer Institute, Bethesda, Maryland 20889, USA.
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Koo SJ, Clark-Alderfer JD, Tanaka H, Teillet MA, Schuler B, Le Douarin NM, Conrad GW. Species-specific immunostaining of embryonic corneal nerves: techniques for inactivating endogenous peroxidases and demonstration of lateral diffusion of antibodies in the plane of the corneal stroma. J Neurosci Methods 1998; 85:63-71. [PMID: 9874142 DOI: 10.1016/s0165-0270(98)00122-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Species-specific and species-common monoclonal antibodies (MAbs) to nerve-specific cell surface epitopes were used to compare pre-treatment techniques for nerve staining. Endogenous peroxidases were inactivated in four ways: (1) 0.3% hydrogen peroxide (H2O2); (2) 1% periodic acid (PA) (pH 1.85-1.95); (3) sodium meta-periodate (10-40 mM, pH 4.5); or (4) HCl (pH 1.80). Staining of chick and quail corneal nerves and dorsal root ganglia (DRG) nerves with the MAbs was species-specific. Staining of chick and quail corneal nerves was unaffected by pre-treatment with 0.3% H2O2, but was eliminated by pre-treatment with 1% PA. Chick and quail DRG nerve staining tolerated 0.3% H2O2, and at least one epitope also tolerated 1% PA. Corneal nerves of both chick and quail displayed concentration-dependent sensitivity to pre-treatment with sodium meta-periodate; DRG nerves were not sensitive to such pre-treatment. Corneal nerves tolerated pre-treatment with HCI (pH 1.80), whereas DRG nerves did not. These findings indicate sensitivity of corneal nerve epitopes to oxidation, in contrast with sensitivity of DRG nerve epitopes to low pH. Results also indicate that tissue trimming regulated whole-mount staining of corneal nerves, suggesting that antibodies cannot diffuse across corneal basement membranes, even after detergent extraction. However, antibodies are able to diffuse laterally into the stroma from any cut edge.
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Affiliation(s)
- S J Koo
- Division of Biology, Ackert Hall, Kansas State University, Manhattan 66506-4901, USA
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Miller S, Schuler B, Seckler R. Phage P22 tailspike protein: removal of head-binding domain unmasks effects of folding mutations on native-state thermal stability. Protein Sci 1998; 7:2223-32. [PMID: 9792111 PMCID: PMC2143837 DOI: 10.1002/pro.5560071021] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A shortened, recombinant protein comprising residues 109-666 of the tailspike endorhamnosidase of Salmonella phage P22 was purified from Escherichia coli and crystallized. Like the full-length tailspike, the protein lacking the amino-terminal head-binding domain is an SDS-resistant, thermostable trimer. Its fluorescence and circular dichroism spectra indicate native structure. Oligosaccharide binding and endoglycosidase activities of both proteins are identical. A number of tailspike folding mutants have been obtained previously in a genetic approach to protein folding. Two temperature-sensitive-folding (tsf) mutations and the four known global second-site suppressor (su) mutations were introduced into the shortened protein and found to reduce or increase folding yields at high temperature. The mutational effects on folding yields and subunit folding kinetics parallel those observed with the full-length protein. They mirror the in vivo phenotypes and are consistent with the substitutions altering the stability of thermolabile folding intermediates. Because full-length and shortened tailspikes aggregate upon thermal denaturation, and their denaturant-induced unfolding displays hysteresis, kinetics of thermal unfolding were measured to assess the stability of the native proteins. Unfolding of the shortened wild-type protein in the presence of 2% SDS at 71 degrees C occurs at a rate of 9.2 x 10(-4) s(-1). It reflects the second kinetic phase of unfolding of the full-length protein. All six mutations were found to affect the thermal stability of the native protein. Both tsf mutations accelerate thermal unfolding about 10-fold. Two of the su mutations retard thermal unfolding up to 5-fold, while the remaining two mutations accelerate unfolding up to 5-fold. The mutational effects can be rationalized on the background of the recently determined crystal structure of the protein.
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Affiliation(s)
- S Miller
- Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Germany
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Abstract
The folding of the trimeric phage P22 tailspike protein is influenced by amino acid substitutions of two types, virtually all of which affect residues in the central domain, a large parallel beta-helix. Temperature sensitive folding (tsf) mutations lead to drastically decreased folding yields at elevated temperature. Their phenotype can be alleviated by global suppressor (su) mutations. Both types of mutations appeared to have no influence on the stability of the native protein at the time of their first isolation and were thus suggested to carry information needed for the folding pathway exclusively. The monomeric beta-helix of tailspike, expressed as an isolated domain, exhibits freely reversible unfolding and refolding transitions, allowing us to analyse the effects of two well-characterised tsf and all four known su mutations on its thermodynamic stability. We find a marked decrease in stability for the tsf mutants and a striking increase in stability for all su mutants. This leads to the conception that the isolated beta-helix domain, although active in receptor-binding and native-like in its spectroscopic properties, is close in conformation to a crucial monomeric folding intermediate whose thermolability is responsible for the kinetic partitioning between productive folding and irreversible aggregation during the maturation process of P22 tailspike protein.
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Affiliation(s)
- B Schuler
- Physikalische Biochemie, Universität Regensburg, Universitätsstrasse 31, 93040 Regensburg, Germany
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Miller S, Schuler B, Seckler R. A reversibly unfolding fragment of P22 tailspike protein with native structure: the isolated beta-helix domain. Biochemistry 1998; 37:9160-8. [PMID: 9636063 DOI: 10.1021/bi980190e] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The homotrimeric tailspike endorhamnosidase of phage P22 has been used to compare in vivo and in vitro folding pathways and the influence of single amino acid substitutions thereon. Its main structural motif, which contains the known folding mutation sites, consists of three large right-handed parallel beta-helices. A thermodynamic analysis of the stability of tailspike is prevented by the irreversibility of unfolding at high temperatures or high concentrations of denaturant, probably due to interdigitation of the domains neighboring the beta-helix. We therefore expressed and isolated a tailspike fragment comprising only its central beta-helix domain (residues 109-544). As shown by equilibrium ultracentrifugation, the isolated beta-helix is a monomer at concentrations below 1 microM and trimerizes reversibly at higher protein concentrations. Both the similarity of fluorescence and CD spectra, compared to the complete protein, and the specific binding and hydrolysis of substrate suggest a nativelike structure. Moreover, urea denaturation transitions of the beta-helix domain are freely reversible, providing the basis for a future quantitative analysis of the effects of the folding mutations on the thermodynamic stability of the domain and of structural features responsible for folding and stability of the parallel beta-helix motif in general.
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Affiliation(s)
- S Miller
- Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Germany
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Georgiadis MS, Schuler B, Johnson BE. Four-day paclitaxel infusion with cisplatin for patients with lung cancer. Semin Oncol 1995; 22:67-9. [PMID: 7544027] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Lung cancer cell lines are between seven and 1,000 times more sensitive to paclitaxel (Taxol; Bristol-Myers Squibb Co, Princeton, NJ) when exposed for 120 hours (5 days) compared with 3-hour exposure. A phase I study of 4-day infusion of paclitaxel plus bolus cisplatin for patients with lung cancer has defined the recommended phase II dose. In this study, paclitaxel infused at 30 mg/m2/d for 4 days followed by a cisplatin bolus of 80 mg/m2 after infusion completion was associated with acceptable hematologic toxicity. Nine of the 16 patients with non-small cell lung cancer treated with at least two cycles of this regimen attained an objective tumor response (one complete response and eight partial responses; overall response rate, 56%). The recommended phase II dose of a 4-day infusion of paclitaxel plus bolus cisplatin followed by the administration of granulocyte colony-stimulating factor has not yet been determined.
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Affiliation(s)
- M S Georgiadis
- National Cancer Institute-Navy Medical Oncology Branch, National Cancer Institute, Bethesda, MD 20889-5105, USA
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Fadlallah N, Guy N, Teillet MA, Schuler B, Le Douarin NM, Naquet R, Batini C. Brain chimeras for the study of an avian model of genetic epilepsy: structures involved in sound and light-induced seizures. Brain Res 1995; 675:55-66. [PMID: 7796153 DOI: 10.1016/0006-8993(95)00038-r] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [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: 01/27/2023]
Abstract
The epileptic homozygotes of the Fayoumi strain of chickens (Fepi) are affected by photogenic reflex epilepsy with complete penetrance. Here we demonstrate that they are equally affected by audiogenic reflex epilepsy induced by intense sound stimulation. All the Fepi display sound-induced seizures from hatching to adulthood consisting of initial 'ictal arousal' and running fits usually followed by generalized clonico-tonic convulsions. A running fit is the preconvulsive motor symptom specifically induced by auditory stimulation while neck myoclonus is the preconvulsive motor symptom specifically induced by photic stimulation. The EEG interictal spikes and spike and waves are suppressed and replaced by a desynchronized trace during the seizures of both kinds. Viable neural chimeras were obtained by graft of embryonic brain vesicles from Fepi donors into normal chick embryos. Transfer of the complete audiogenic and photogenic phenotypes was obtained in chimeras resulting from embryonic substitution of both the prosencephalon and mesencephalon. The substitution of the prosencephalon alone resulted in transfer of interictal paroxysmal EEG activity accompanied by the sound and light-induced desynchronization and 'ictal arousal' with no motor seizures. Chimeras with embryonic substitution of the mesencephalon alone displayed running fits and convulsions induced by sound stimulation but only neck myoclonus following light stimulation. The conclusions are reached that: (i) the Fepi is a model of audiogenic and photogenic reflex epilepsy; (ii) in both types, the seizure initiator and the convulsion generator are localized in the brainstem, although reinforcement from telencephalic visual structures is needed to trigger photogenic generalized convulsions.
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Affiliation(s)
- N Fadlallah
- Laboratoire de Physiologie de la Motricité, CNRS et Université Pierre et Marie Curie, Paris, France
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Teillet MA, Guy N, Fadlallah N, Le Gal La Salle G, Schuler B, Batini C, Le Douarin N, Naquet R. Reflex epilepsy of the fowl and its transfer to normal chickens by brain embryonic grafts. Ital J Neurol Sci 1995; 16:83-89. [PMID: 7642357 DOI: 10.1007/bf02229079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The genetic photosensitive epilepsy of the Fayoumi chicken was transferred to normal chickens by in situ grafts at 2 days of incubation, of both the prosencephalic and mesencephalic brain vesicles taken from epileptic embryos. However, mesencephalic graft is sufficient to allow convulsions under sound stimulation. Typical EEG patterns are recorded in chimeras having the prosencephalon plus or not the mesencephalon. We conclude that, in this mutant, the whole neural tissue is affected, but the seizure generator is localized inside the mesencephalon, and specific sensory pathways are necessary for seizures to occur.
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Affiliation(s)
- M A Teillet
- Institut d'Embryologie Cellulaire et Moléculaire, CNRS-UMRC 9924, Nogent/Marne, France
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Teillet MA, Guy NT, Schuler B, Le Gal La Salle G, Batini C, Le Douarin NM, Naquet R. Transfer of a genetic form of epilepsy in the chicken by embryonic brain grafts. C R Acad Sci III 1993; 316:1164-76. [PMID: 8076211] [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: 01/28/2023]
Abstract
The genetic photosensitive epilepsy of the Fayoumi chickens was transferred to normal chickens by grafting, in situ, on the 2nd day of incubation, the prosencephalic and mesencephalic vesicles from epileptic embryos. Such chimeras displayed typical interictal EEG and developed intermittent light stimulation-induced seizures phenotypically and electrically similar to the epileptic strain seizures.
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Affiliation(s)
- M A Teillet
- Institut d'Embryologie Cellulaire et Moléculaire, CNRS-UMRC 9924, Collège de France, Nogent-sur-Marne, France
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Guy N, Teillet MA, Schuler B, Le Gal la Salle G, Le Douarin N, Naquet R, Batini C. Pattern of electroencephalographic activity during light induced seizures in genetic epileptic chicken and brain chimeras. Neurosci Lett 1992; 145:55-8. [PMID: 1461568 DOI: 10.1016/0304-3940(92)90202-i] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [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: 12/27/2022]
Abstract
Genetic epilepsy was studied in Fayoumi epileptic (F.Epi) chickens and in neural chimeras obtained by selective substitution of embryonic brain vesicles of F.Epi donors in normal recipient chickens. Typical motor seizures accompanied by convulsions were evoked by intermittent light stimulation in F.Epi and in chimeras having embryonic substitution of the prosencephalon and the mesencephalon. The motor seizure was less severe in chimeras receiving only the prosencephalon. In the F.Epi, as well as in all the chimeras, the EEG during seizures was characterized by a desynchronized (or a flattening) pattern of activity. F.Epi and chimeras had a lower threshold to Metrazol induced seizures than control chickens. The experimental animals show that, in this model, large prosencephalic and mesencephalic areas are involved in the epileptic disease. The epileptic character of this genetic dysfunction is discussed.
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Affiliation(s)
- N Guy
- Laboratoire de Physiologie de la Motricité, CNRS-URA 385, Paris, France
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Teillet MA, Naquet R, Le Gal La Salle G, Merat P, Schuler B, Le Douarin NM. Transfer of genetic epilepsy by embryonic brain grafts in the chicken. Proc Natl Acad Sci U S A 1991; 88:6966-70. [PMID: 1871111 PMCID: PMC52214 DOI: 10.1073/pnas.88.16.6966] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [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: 12/29/2022] Open
Abstract
In the Fayoumi chicken, a spontaneous recessive autosomal mutation (F.Epi) is responsible for high susceptibility to seizures that are especially inducible by intermittent light stimulation. Substitution of defined areas of the encephalic neuroepithelium in normal chicken embryos at 2 days of incubation by their counterparts from homozygous F.Epi embryos generates the epileptic phenotype in the chimeras. It was found that grafting primordia of both prosencephalon and mesencephalon of homozygous F.Epi birds is necessary and sufficient for transfer of the full disease. When grafted alone, the homozygous F.Epi prosencephalon, although showing the typical epileptic interictal electroencephalogram, does not allow the complete epileptic seizures to occur in the hosts. Grafts of mesencephalon and/or rhombencephalon modify neither the behavior nor the electroencephalographic pattern of the recipient chickens. Cooperation of forebrain and midbrain activities is therefore required to yield epileptic seizures in this model.
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Affiliation(s)
- M A Teillet
- Institut d'Embryologie Cellulaire et Moléculaire du Centre National de la Recherche Scientifique et du Collège de France, Nogent-sur-Marne
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Abstract
The present therapy experiments with two different transplantable mammary tumors were performed to compare the therapeutic efficacy in BD-VI rats of 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3) and hexadecylphosphocholine (HPC). Both compounds were administered orally, subcutaneously or intracutaneously at equimolar doses ranging from 4.8 to 88 mumol/kg/day five times per week for two weeks. Under the experimental conditions, both transplanted mammary carcinomas were moderately sensitive to the therapy with either HPC or ET-18-OCH3. Comparing both tumors, TMA2 was more sensitive than TMA1. The activity and toxicity of both compounds were dose-related in both tumor lines. Females seemed to be less sensitive with respect to antineoplastic activity and toxicity. Like ET-18-OCH3, HPC was active also at low, probably noncytotoxic doses associated with no detectable toxicity according to body weight development. This suggests that there are at least two different mechanisms of action that lead to tumor growth inhibition.
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Affiliation(s)
- H R Scherf
- Institute of Toxicology and Chemotherapy, German Cancer Research Center, Heidelberg, Federal Republic of Germany
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Muschiol C, Berger MR, Schuler B, Scherf HR, Garzon FT, Zeller WJ, Unger C, Eibl HJ, Schmähl D. Alkyl phosphocholines: toxicity and anticancer properties. Lipids 1987; 22:930-4. [PMID: 3444388 DOI: 10.1007/bf02535558] [Citation(s) in RCA: 59] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The study reports on the investigation of acute and subacute toxicity and on antineoplastic activity of hexadecylphosphocholine (HPC), the first compound of a new class of antineoplastic chemotherapeutics. In rats, the LD50 of HPC was 606 mumol/kg; the maximum tolerable dose over four weeks was 39 mumol/kg. Symptoms of toxicity were enteritis, spider cell activation in the liver, hemosiderosis in the spleen and reversible transaminase increase. The best therapeutic effect was observed on methylnitrosourea (MNU)-induced mammary carcinoma in the rat. Two transplantable mammary carcinomas in the rat and autochthonous benzo(a)pyrene-induced sarcomas exhibited low-grade sensitivity to HPC. The MXT mammary carcinoma of the mouse, the Walker 256 carcinosarcoma of the rat, and autochthonous acetoxymethylmethylnitrosamine-induced colonic tumors of the rat were not chemosensitive to HPC.
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Affiliation(s)
- C Muschiol
- Institute of Toxicology and Chemotherapy, German Cancer Research Center, Heidelberg, Federal Republic of Germany
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Abstract
The need for quick viability tests is stressed. Aas these should achieve more than statically categorizing dead or non-dead cells, several procedures are suggested that picture the energetic state of the cells. The almost classical criterion of this category, namely stimulation of respiration by succinate, must be questioned on the basis of the present results. It is shown, that restricted respiration by succinate is not due to limited permeability of the plasma membrane, but to competition by endogenous substrates for uptake into mitochondria. Distribution equilibria for succinate appear to be according to (delta pH)2 with regard to cytoplasm. They are attained within 5-20 s or faster. Uptake is in part regulated by the surface charge density. Permeability changes caused by effectors of surface charge, such as amphiphilic ions, are examplified for succinate, chloride, phosphate, Na+, K+, and Ca2+. Such changes repeatedly also occur after pulses of BSP. They are counterregulated by the cell within a minute in a manner dependent on BSP concentration and the state of the cells. During the preincubation phase, that is the time of readaptation after transfer of cells from 0 degree C to higher temperature, a special labile state transiently occurs, where cyclic permeability changes for Ca2+, Na+, K+ can be caused by substrate addition, especially succinate, and/or ATP. The extent of these changes and their sequence again depend on the energetic state of the cells. In a probably narrow energetic window a sequence of cation movements reminding of that after depolarization of an excitable cell, is observed. Manipulation of the Na+/K+-ratio by variation of preincubation time and by ouabain shows that this is not simply the denominator for reversible calcium uptake. As the surface charge appears to reflect the energetic state, ANS fluorescence is applied to monitor the state of the plasma membrane, though difficulties arising from a slow ANS permeation are not yet solved.
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Cruz A, Schuler B. [Errors in the diagnosis of systemic lupus erythematosus]. Z Rheumaforsch 1970; 29:102-7. [PMID: 5506503] [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: 01/15/2023]
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Schuler B. [Soft tissue rheumatism? A critical semeiological study]. Z Allgemeinmed 1969; 45:145-51. [PMID: 5306534] [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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Dihlmann W, Schuler B. Schlußwort zur Entgegnung von Kamieth auf unsere Arbeit. Fortschr. Röntgenstr. 98/2 (1963), 134. ROFO-FORTSCHR RONTG 1963. [DOI: 10.1055/s-0029-1227302] [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: 10/20/2022]
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Martini P, Schuler B. Spektralphotometrische Blutuntersuchungen. Die veränderung des Oxyhämoglobins unter dem Einfluß ultravioletter Strahlen. Clin Exp Med 1932. [DOI: 10.1007/bf02598813] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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