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Citerni C, Kirchhoff J, Olsen LH, Sattler SM, Grunnet M, Edvardsson N, Bentzen BH, Diness JG. Inhibition of K Ca2 and K v11.1 Channels in Pigs With Left Ventricular Dysfunction. Front Pharmacol 2020; 11:556. [PMID: 32435191 PMCID: PMC7219273 DOI: 10.3389/fphar.2020.00556] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 04/14/2020] [Indexed: 12/17/2022] Open
Abstract
Background Inhibition of KCa2 channels, conducting IKCa, can convert atrial fibrillation (AF) to sinus rhythm and protect against its induction. IKCa inhibition has been shown to possess functional atrial selectivity with minor effects on ventricles. Under pathophysiological conditions with ventricular remodeling, however, inhibiting IKCa can exhibit both proarrhythmic and antiarrhythmic ventricular effects. The aim of this study was to evaluate the effects of the IKCa inhibitor AP14145, when given before or after the IKr blocker dofetilide, on cardiac function and ventricular proarrhythmia markers in pigs with or without left ventricular dysfunction (LVD). Methods Landrace pigs were randomized into an AF group (n = 6) and two control groups: SHAM1 (n = 8) and SHAM2 (n = 4). AF pigs were atrially tachypaced (A-TP) for 43 ± 4 days until sustained AF and LVD developed. A-TP and SHAM1 pigs received 20 mg/kg AP14145 followed by 100 µg/kg dofetilide whereas SHAM2 pigs received the same drugs in the opposite order. Proarrhythmic markers such as short-term variability of QT (STVQT) and RR (STVRR) intervals, and the number of premature ventricular complexes (PVCs) were measured at baseline and after administration of drugs. The influence on cardiac function was assessed by measuring cardiac output, stroke volume, and relevant echocardiographic parameters. Results IKCa inhibition by AP14145 did not increase STVQT or STVRR in any of the pigs. IKr inhibition by dofetilide markedly increased STVQT in the A-TP pigs, but not in SHAM operated pigs. Upon infusion of AP14145 the number of PVCs decreased or remained unchanged both when AP14145 was infused after baseline and after dofetilide. Conversely, the number of PVCs increased or remained unchanged upon dofetilide infusion. Neither AP14145 nor dofetilide affected relevant echocardiographic parameters, cardiac output, or stroke volume in any of the groups. Conclusion IKCa inhibition with AP14145 was not proarrhythmic in healthy pigs, or in the presence of LVD resulting from A-TP. In pigs already challenged with 100 µg/kg dofetilide there were no signs of proarrhythmia when 20 mg/kg AP14145 were infused. KCa2 channel inhibition did not affect cardiac function, implying that KCa2 inhibitors can be administered safely also in the presence of LV dysfunction.
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Affiliation(s)
- Carlotta Citerni
- Biomedical Institute, University of Copenhagen, Copenhagen, Denmark.,Acesion Pharma, Copenhagen, Denmark
| | | | - Lisbeth Høier Olsen
- Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg, Denmark
| | - Stefan Michael Sattler
- Biomedical Institute, University of Copenhagen, Copenhagen, Denmark.,Department of Cardiology, Heart Center, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | | | - Nils Edvardsson
- Acesion Pharma, Copenhagen, Denmark.,Department of Molecular and Clinical Medicine, Sahlgrenska Academy at Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Bo Hjorth Bentzen
- Biomedical Institute, University of Copenhagen, Copenhagen, Denmark.,Acesion Pharma, Copenhagen, Denmark
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Citerni C, Kirchhoff J, Olsen LH, Sattler SM, Gentilini F, Forni M, Zannoni A, Grunnet M, Edvardsson N, Bentzen BH, Diness JG. Characterization of Atrial and Ventricular Structural Remodeling in a Porcine Model of Atrial Fibrillation Induced by Atrial Tachypacing. Front Vet Sci 2020; 7:179. [PMID: 32328502 PMCID: PMC7160334 DOI: 10.3389/fvets.2020.00179] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 03/19/2020] [Indexed: 12/12/2022] Open
Abstract
Background: Atrial fibrillation (AF) is characterized by electrical and structural remodeling. Irregular and/or fast atrio-ventricular (AV) conduction during AF can result in AV dyssynchrony, tachymyopathy, pressure and volume overload with subsequent dilatation, valve regurgitation, and ventricular dysfunction with progression to heart failure. Objective: To gain further insight into the myocardial pathophysiological changes induced by right atrial tachypacing (A-TP) in a large animal model. Methods: A total of 28 Landrace pigs were randomized as 14 into AF-induced A-TP group and 14 pigs to control group. AF pigs were tachypaced for 43 ± 4 days until in sustained AF. Functional remodeling was investigated by echocardiography (after cardioversion to sinus rhythm). Structural remodeling was quantified by histological preparations with picrosirius red and immunohistochemical stainings. Results: A-TP resulted in decreased left ventricular ejection fraction (LVEF) accompanied by increased end-diastolic and end-systolic left atrium (LA) volume and area. In addition, A-TP was associated with mitral valve (MV) regurgitation, diastolic dysfunction and increased atrial and ventricular fibrotic extracellular matrix (ECM). Conclusions: A-TP induced AF with concomitant LV systolic and diastolic dysfunction, increased LA volume and area, and atrial and ventricular fibrosis.
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Affiliation(s)
- Carlotta Citerni
- Biomedical Institute, University of Copenhagen, Copenhagen, Denmark.,Acesion Pharma, Copenhagen, Denmark
| | | | - Lisbeth Høier Olsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Stefan Michael Sattler
- Biomedical Institute, University of Copenhagen, Copenhagen, Denmark.,Department of Cardiology, Heart Center, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Medical Department I, University Hospital Grosshadern, LMU Munich, Munich, Germany
| | - Fabio Gentilini
- Department of Veterinary Medical Sciences, University of Bologna, Bologna, Italy
| | - Monica Forni
- Department of Veterinary Medical Sciences, University of Bologna, Bologna, Italy
| | - Augusta Zannoni
- Department of Veterinary Medical Sciences, University of Bologna, Bologna, Italy
| | | | - Nils Edvardsson
- Acesion Pharma, Copenhagen, Denmark.,Department of Molecular and Clinical Medicine/Cardiology, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Bo Hjorth Bentzen
- Biomedical Institute, University of Copenhagen, Copenhagen, Denmark.,Acesion Pharma, Copenhagen, Denmark
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3
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Citerni C, Kirchhoff J, Olsen L, Gentilini F, Forni M, Zannoni A, Edvardsson N, Bentzen B, Grunnet M, Diness J. P3811SK channel inhibition did not increase short-term variability of the QT intervals in atrial tachypaced pigs with left ventricular dysfunction in contrast to the positive control dofetilide. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy563.p3811] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- C Citerni
- University of Copenhagen, biomedical institute, Copenhagen, Denmark
| | | | - L Olsen
- University of Copenhagen, Department of Veterinary Disease Biology, Copenhagen, Denmark
| | - F Gentilini
- University of Bologna, Department of Veterinary Medical Sciences, Bologna, Italy
| | - M Forni
- University of Bologna, Department of Veterinary Medical Sciences, Bologna, Italy
| | - A Zannoni
- University of Bologna, Department of Veterinary Medical Sciences, Bologna, Italy
| | - N Edvardsson
- University of Gothenburg, Sahlgrenska University Hospital, Gothenburg, Sweden
| | | | | | - J Diness
- Acesion Pharma, Copenhagen, Denmark
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Liu JP, Kirchhoff J, Zhou L, Zhao M, Grapes MD, Dale DS, Tate MD, Philipp HT, Gruner SM, Weihs TP, Hufnagel TC. X-ray reflectivity measurement of interdiffusion in metallic multilayers during rapid heating. J Synchrotron Radiat 2017; 24:796-801. [PMID: 28664887 PMCID: PMC5493026 DOI: 10.1107/s1600577517008013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 05/30/2017] [Indexed: 06/07/2023]
Abstract
A technique for measuring interdiffusion in multilayer materials during rapid heating using X-ray reflectivity is described. In this technique the sample is bent to achieve a range of incident angles simultaneously, and the scattered intensity is recorded on a fast high-dynamic-range mixed-mode pixel array detector. Heating of the multilayer is achieved by electrical resistive heating of the silicon substrate, monitored by an infrared pyrometer. As an example, reflectivity data from Al/Ni heated at rates up to 200 K s-1 are presented. At short times the interdiffusion coefficient can be determined from the rate of decay of the reflectivity peaks, and it is shown that the activation energy for interdiffusion is consistent with a grain boundary diffusion mechanism. At longer times the simple analysis no longer applies because the evolution of the reflectivity pattern is complicated by other processes, such as nucleation and growth of intermetallic phases.
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Affiliation(s)
- J. P. Liu
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, People’s Republic of China
| | - J. Kirchhoff
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - L. Zhou
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - M. Zhao
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - M. D. Grapes
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - D. S. Dale
- Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853, USA
| | - M. D. Tate
- Department of Physics, Cornell University, Ithaca, NY 14853, USA
| | - H. T. Philipp
- Department of Physics, Cornell University, Ithaca, NY 14853, USA
| | - S. M. Gruner
- Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853, USA
- Department of Physics, Cornell University, Ithaca, NY 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY 14853, USA
| | - T. P. Weihs
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - T. C. Hufnagel
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
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Dellavalle B, Kirchhoff J, Maretty L, Castberg FC, Kurtzhals JAL. Implementation of minimally invasive and objective humane endpoints in the study of murine Plasmodium infections. Parasitology 2014; 141:1-7. [PMID: 24993593 DOI: 10.1017/s0031182014000821] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SUMMARY Defining appropriate and objective endpoints for animal research can be difficult. Previously we evaluated and implemented a body temperature (BT) of <32 °C as an endpoint for experimental cerebral malaria (ECM) and were interested in a similar endpoint for a model of severe malarial anaemia (SMA). Furthermore, we investigate the potential of a minimally invasive, non-contact infrared thermometer for repeated BT measurement. ECM was induced with Plasmodium berghei ANKA infection in C57Bl/6 mice. SMA was induced with Plasmodium chabaudi AS infection in A/J mice. Our previous published endpoint was applied in ECM and 30 °C was pre-determined as the lowest permitted limit for termination in SMA according to consultation with the Danish Animal Inspectorate. Infrared thermometer was compared with the rectal probe after cervical dislocation, ECM and SMA. Linear regression analysis of rectal versus infrared thermometry: cervical dislocation: Pearson R = 0·99, R 2 = 0·98, slope = 1·01, y-intercept = 0·55; ECM: 0·99, 0·98, 1·06, -2·4; and SMA: 0·98, 0·97, 1·14, -5·6. Implementation of the 30 °C endpoint captured all lethal infections. However, some animals with BT below 30 °C were not deemed clinically moribund. This study supports repeated measurement infrared thermometry. A humane endpoint of 30 °C was sensitive in capturing terminal animals but might overestimate lethality in this SMA model.
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Affiliation(s)
- B Dellavalle
- Centre for Medical Parasitology, Department of Clinical Microbiology,Copenhagen University Hospital,Copenhagen,Denmark
| | - J Kirchhoff
- Centre for Medical Parasitology, Department of Clinical Microbiology,Copenhagen University Hospital,Copenhagen,Denmark
| | - L Maretty
- Centre for Medical Parasitology, Department of Clinical Microbiology,Copenhagen University Hospital,Copenhagen,Denmark
| | - F C Castberg
- Centre for Medical Parasitology, Department of Clinical Microbiology,Copenhagen University Hospital,Copenhagen,Denmark
| | - J A L Kurtzhals
- Centre for Medical Parasitology, Department of Clinical Microbiology,Copenhagen University Hospital,Copenhagen,Denmark
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Bird MK, Lohmann P, West B, Brown RM, Kirchhoff J, Raymond CR, Lawrence AJ. The mGlu5 receptor regulates extinction of cocaine-driven behaviours. Drug Alcohol Depend 2014; 137:83-9. [PMID: 24576814 DOI: 10.1016/j.drugalcdep.2014.01.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 01/07/2014] [Accepted: 01/13/2014] [Indexed: 11/24/2022]
Abstract
BACKGROUND There is extensive evidence implicating the metabotropic glutamate 5 (mGlu5) receptor in aspects of addiction-related behaviours. METHODS Here, we used a well-characterized line of mGlu5-deficient mice to further examine the role of this receptor in cocaine-driven behaviours. We confirmed the previously reported deficit in hippocampal long-term potentiation and associated spatial learning impairment. RESULTS Despite a spatial learning deficit, mGlu5-deficient mice developed and maintained a conditioned place preference to cocaine, suggesting cocaine reward and Pavlovian conditioning are intact in these animals. Notably, however, mGlu5-deficient mice exhibited a marked deficit in the extinction of a cocaine-conditioned place preference compared to wild type littermates. Moreover, in a fixed ratio operant intravenous self-administration paradigm, both genotypes showed similar responding for cocaine over two different doses, while mGlu5-deficient mice displayed enhanced responding on a progressive ratio schedule. In addition, cue-induced drug-seeking after abstinence was exaggerated in mGlu5-deficient mice. CONCLUSION Collectively, these findings suggest that while the mGlu5 receptor may be involved in mediating the rewarding effects of cocaine, it appears necessary for the extinction of cocaine-driven behaviours.
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Affiliation(s)
- Michael K Bird
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia
| | - Peter Lohmann
- The John Curtin School of Medical Research & Eccles Institute of Neuroscience, Australian National University, Canberra, Australia
| | - Billy West
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia
| | - Robyn M Brown
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia; Medical University of South Carolina, Charleston, SC, USA
| | - Jeppe Kirchhoff
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia
| | - Clarke R Raymond
- The John Curtin School of Medical Research & Eccles Institute of Neuroscience, Australian National University, Canberra, Australia
| | - Andrew J Lawrence
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia.
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7
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Kamusella P, Wissgott C, Kirchhoff J, Richter J, Kloppmann E, Brossmann J, Andresen R. Einsatz eines neuen perkutanen Gefäßverschlusssystems nach 6F transfemoralen Zugängen: erste Ergebnisse von 100 Patienten. ROFO-FORTSCHR RONTG 2012. [DOI: 10.1055/s-0032-1311077] [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: 10/28/2022]
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8
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Kirchhoff J, Hirst LS. Modification of the electro-optical properties of the B1 liquid-crystal phase using a rodlike liquid-crystal dopant. Phys Rev E Stat Nonlin Soft Matter Phys 2010; 82:031701. [PMID: 21230085 DOI: 10.1103/physreve.82.031701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Indexed: 05/30/2023]
Abstract
It has recently been observed that on application of an alternating electric field, the B1 liquid-crystalline phase may be induced to form a switchable phase. This induced phase has been shown to have an almost thresholdless dielectric response. In this paper we examine this E-field-induced transition as a function of temperature both with and without a ferroelectric liquid-crystal dopant. Although the aim of this experiment was to enhance and stabilize the field-induced phase on addition of dopant, we find that the opposite is the case. The ferroelectric dopant actually increases the threshold E-fields required for transformation to the switching phase and at just 5 wt % dopant a smectic-A phase is formed. Addition of the dopant also acts against the low-field switching and significantly speeds relaxation back to the B1 phase on field removal. In addition we find that the field-induced phase experiences a slower crystallization. We use polarized optical microscopy, differential scanning calorimetry, and x-ray scattering experiments to characterize the physical properties of the mixtures.
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Affiliation(s)
- J Kirchhoff
- MARTECH, Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
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9
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Sager TN, Kirchhoff J, Mørk A, Van Beek J, Thirstrup K, Didriksen M, Lauridsen JB. Nest building performance following MPTP toxicity in mice. Behav Brain Res 2010; 208:444-9. [DOI: 10.1016/j.bbr.2009.12.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Revised: 12/08/2009] [Accepted: 12/14/2009] [Indexed: 10/20/2022]
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10
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Wachsmann F, Buchheim CE, Kirchhoff J. Die Helligkeit von Röntgenleuchtschirmen bei verschiedenen Röhrenspannungen und die Frage der zweckmäßigen, höchsten Durchleuchtungsspannung*. ROFO-FORTSCHR RONTG 2009. [DOI: 10.1055/s-0029-1226213] [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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Kirchhoff J, Mørk A, Brennum LT, Sager TN. Striatal extracellular dopamine levels and behavioural reversal in MPTP-lesioned mice. Neuroreport 2009; 20:482-6. [DOI: 10.1097/wnr.0b013e32832984d6] [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: 11/25/2022]
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12
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Kirchhoff J, Hirst LS. Investigation into liquid crystalline smectic-C* subphase stability using chiral and achiral dopants. Phys Rev E Stat Nonlin Soft Matter Phys 2007; 76:051704. [PMID: 18233670 DOI: 10.1103/physreve.76.051704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2007] [Indexed: 05/25/2023]
Abstract
In this paper we investigate the influence of chiral and achiral dopants on a chiral smectic liquid crystal material, which exhibits a rich phase sequence, including the antiferroelectric phase and the three-layer intermediate smectic (SmC*FI1) phase. Using polarized optical microscopy, differential scanning calorimetry, and x-ray diffraction we find that small amounts of achiral dopant have the ability to significantly broaden the SmC*FI1 phase, whereas an oppositely-handed dopant (otherwise identical to the host material) destabilizes the phase. This work clearly indicates that bulk chirality strongly influences SmC*FI1 phase formation and that steric effects also play an important role. Interestingly, addition of the shorter achiral molecule (8CB) was observed to increase the smectic layer spacing, most likely by suppressing interdigitation of alkyl chains between adjacent smectic layers. Control of the SmC*FI1 phase width using mixtures in this way is clearly important for effective phase characterization, and could potentially lead to commercially viable materials with a stable SmC*FI1 phase over a large temperature range.
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Affiliation(s)
- J Kirchhoff
- MARTECH, Department of Physics, Florida State University, Florida 32306, USA
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13
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Moore R, Krstew EV, Kirchhoff J, Davisson RL, Lawrence AJ. Central Overexpression of Angiotensin AT1AReceptors Prevents Dopamine D2Receptor Regulation of Alcohol Consumption in Mice. Alcohol Clin Exp Res 2007; 31:1128-37. [PMID: 17451402 DOI: 10.1111/j.1530-0277.2007.00399.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [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: 01/15/2023]
Abstract
BACKGROUND While angiotensin receptors are found on the soma and terminals of dopaminergic neurons, controversy surrounds the potential role of angiotensin in alcohol consumption. METHODS Using a transgenic mouse with a brain-specific overexpression of angiotensin AT(1A) receptors (NSE-AT(1A) mice), we have examined the role of angiotensin in alcohol consumption and alcohol-induced regulation of the dopaminergic system. RESULTS The functional relevance of the overexpressed AT(1A) receptors was confirmed by an exaggerated rehydration response following 24-hour dehydration. NSE-AT(1A) mice showed a high preference for alcohol (similar to wild-type mice); yet, raclopride treatment had no effect on alcohol consumption in NSE-AT(1A) mice, while significantly reducing consumption in wild-type mice. In contrast, NSE-AT(1A) mice showed enhanced sensitivity to raclopride compared with wild types in terms of D(2) receptor up-regulation within the ventral mesencephalon. In addition, striatal D(2) receptors in NSE-AT(1A) mice were sensitive to up-regulation by chronic alcohol consumption. CONCLUSIONS Collectively, these data imply that while expression of angiotensin AT(1A) receptors on striatal neurons has no impact upon basal alcohol consumption or preference, AT(1A) receptors do modulate the sensitivity of dopamine D(2) receptors to regulation by alcohol and the ability of a D(2) receptor antagonist to reduce consumption.
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Affiliation(s)
- Rosanna Moore
- Howard Florey Institute, University of Melbourne, Parkville, VIC, Australia
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14
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Kirchhoff J, Mewes D. Einsatz der Ultraschalltechnik zum Messen der Materialeigenschaften dünner Elastomerschichten. CHEM-ING-TECH 2000. [DOI: 10.1002/1522-2640(200009)72:9<1082::aid-cite10822>3.0.co;2-w] [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: 11/12/2022]
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15
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Kirchhoff J, Wang X, Ghraf R, Ball P, Knuppen R. Interactions of methylestrogens with cytoplasmic and nuclear estrogen receptors in rat pituitary gland, hypothalamus and uterus. Brain Res 1984; 294:354-8. [PMID: 6322922 DOI: 10.1016/0006-8993(84)91049-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The in vitro affinities to cytoplasmic estrogen receptors of the methylestrogens 2-methylestradiol-17 beta, 4-methylestradiol-17 beta and 4-hydroxy-2-methylestradiol-17 beta, which are useful probes to test the biological importance of 2- or 4-hydroxylation of estradiol-17 beta (catecholestrogen formation), have been determined in hypothalamic, pituitary and uterine tissue of the ovariectomized rat. Moreover, the in vivo capacity of these compounds to translocate estrogen receptors into the cell nucleus of pituitary and uterine tissue has been studied. Methylestrogens exhibited estrogen receptor affinities which were not significantly different from the binding affinity of estradiol-17 beta. When given at a high dose (100 micrograms/animal) their nuclear translocation capacity was equal (4-methylestradiol-17 beta) or even higher (2-methylestradiol-17 beta) than that of estradiol-17 beta. However, at a low dose (5 micrograms/animal) 4-methylestradiol was completely ineffective in both the pituitary gland and the uterus, and 2-methylestradiol-17 beta was less potent than estradiol-17 beta in the pituitary gland.
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16
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Lax ER, Kirchhoff J, Ghraf R, Schriefers H. Effects of fasting on the distribution of cytoplasmic and nuclear oestrogen receptors in rat liver, uterus, pituitary and hypothalamus before and after exogenous oestrogen administration. Hoppe Seylers Z Physiol Chem 1984; 365:335-41. [PMID: 6724526 DOI: 10.1515/bchm2.1984.365.1.335] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The accumulation of oestrogen receptors in the liver cell nuclei of intact female rats 45 min after administration of 100 micrograms 17 alpha-ethynyloestradiol-17 beta i.p., decreased progressively during a 72-h fast from 2550 +/- 860 to 257 +/- 67 fmol/mg DNA, a level not significantly different from that in uninjected animals. Cytoplasmic oestrogen receptor concentrations also decreased, but only to about 60% of the original level (from 84.1 +/- 27.5 to 50.3 +/- 2.09 fmol/mg protein during the fast). Similar differences were found when these parameters were examined in normally fed and 72-h-fasted ovariectomized rats. On the other hand these parameters were unaffected in uterus, pituitary and hypothalamus. Uterine cytoplasmic receptor concentrations remained at about 500 fmol/mg protein during the fasting period, those in the pituitary and hypothalamus at about 230 and 30 fmol/mg protein, respectively. Nor was in vivo translocation in these organs affected by fasting. Regardless of nutritional status, the nuclear oestrogen receptor concentrations in uterus rose from about 500 to 2000 fmol/mg DNA after ethynyloestradiol administration, those in the pituitary and hypothalamus from approximately 250 to 2000 and from 250 to 500 fmol/mg DNA respectively.
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17
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Kirchhoff J, Grünke W, Hoffmann B, Nagel W, Ghraf R. Estrogen agonistic and antagonistic action of 8 non-steroidal antiestrogens on progestin receptor induction in rat pituitary gland and uterus. Brain Res 1983; 289:380-4. [PMID: 6661654 DOI: 10.1016/0006-8993(83)90047-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
All 8 non-steroidal antiestrogens tested considerably increased progestin receptor concentration in the uterus and, to a lesser extent, in the pituitary of ovariectomized rats. However, the pituitary was more sensitive than the uterus to the estrogen antagonistic action of these compounds, in that monohydroxytamoxifen, LY 117,018, enclomiphene, nitromifen, nafoxidine and trans-tamoxifen completely blocked progestin receptor induction by estradiol benzoate. In these tissues the order of the in vitro binding affinity of antiestrogens to cytoplasmic estrogen receptors was not correlated with either their in vivo estrogen agonistic or antagonistic potency.
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18
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Kirchhoff J, Grünke W, Ghraf R. Estrogen induction of progestin receptors in pituitary, hypothalamic and uterine cytosol of androgenized female rats. Brain Res 1983; 275:173-7. [PMID: 6626975 DOI: 10.1016/0006-8993(83)90432-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Female rats treated neonatally with a single dose (1.25 mg/animal) of testosterone propionate and ovariectomized when adult did not respond to a priming dose (20 micrograms/animal) of estradiol-17 beta 3-benzoate and subsequent application of progesterone (2.5 mg/animal) 72 h later with an afternoon surge of luteinizing hormone, which could be induced by the same hormonal regimen in neonatally oil-treated long-term ovariectomized female rats. However, both treatment groups responded equally well to the estrogen stimulus with an increase in cytosolic progestin receptors in hypothalamic and pituitary, as well as uterine tissue. It therefore seems unlikely that the observed loss of sensitivity of the gonadotropin release mechanism in neonatally androgenized, estrogen-primed female rats to a progesterone stimulus can be explained by a loss of progestin receptor induction capacity of estrogen/progestin target tissues involved in gonadotropin secretion.
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Kirchhoff J, Ghraf R, Ball P, Knuppen R. Neonatal defeminization of the luteinizing hormone release mechanism by catecholestrogens: different potencies of 2- and 4-hydroxyestradiol. Brain Res 1983; 268:382-6. [PMID: 6307475 DOI: 10.1016/0006-8993(83)90509-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Female rats were neonatally treated with estradiol-17 beta-benzoate or the long-acting dibenzoate esters of the isomeric catecholestrogens, 2-hydroxyestradiol-17 beta and 4-hydroxyestradiol-17 beta. Estrogen benzoates were administered subcutaneously from day 1 to 5 of life at doses of 0.05, 0.10, 0.50 and 1.00 micrograms/day. All rats were ovariectomized as adults and, 4 weeks later, the luteinizing hormone (LH) response to progesterone (2.5 mg) was tested after priming with estradiol-17 beta-benzoate (20 micrograms). At a dose of 0.5 micrograms/day, estradiol-17 beta-benzoate and 4-hydroxyestradiol-17 beta-dibenzoate were equally effective in neonatally defeminizing the LH surge mechanism. In contrast, up to a dose of 1.00 micrograms/day, 2-hydroxyestradiol-17 beta-dibenzoate did not interfere with the LH response in adult life. In the pituitary gland and uterus of the neonatally defeminized rats estrogen responsiveness of cytosolic progestin receptor induction was unimpaired. Moreover, in the uterus of these rats nuclear translocation of cytosolic progestin receptors was intact.
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Kirchhoff J, Hoffmann B, Ghraf R. Estrogen receptor translocation and replenishment in rat hypothalamus and pituitary gland after the application of catecholestrogen or nonsteroidal antiestrogen. J Steroid Biochem 1983; 18:631-3. [PMID: 6304427 DOI: 10.1016/0022-4731(83)90143-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The time course of nuclear translocation of estrogen receptors and the replenishment of cytosolic receptor concentrations in the pituitary gland and hypothalamus of ovariectomized/adrenalectomized rats after the application of a high dose (0.1 mg/animal) of the catecholestrogens, 2-hydroxyethynylestradiol or 4-hydroxyethynylestradiol, was identical to that seen after the application of the monophenolic estrogen 17 alpha-ethynylestradiol. A distinctly different pattern of receptor distribution between these cell compartments was observed after the application of the nonsteroidal antiestrogen monohydroxytamoxifen (ICI 79,280) resulting in a prolonged depletion of cytosolic receptor concentrations. It therefore seems unlikely that the proposed antiestrogenic properties of 2-hydroxyestrogens are the result of a blocking of cytosolic receptor replenishment but may be explained by a reduced intrinsic nuclear activity of estrogen receptors complexed with 2-hydroxyestrogens.
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Kirchhoff J, Reinhardt W, Grünke W, Ghraf R, Ball P, Knuppen R. Induction of cytosolic progestin binding sites by catecholestrogens in rat pituitary gland and uterus: different potencies of 2- and 4-hydroxyestradiol. J Neurochem 1983; 40:474-80. [PMID: 6296320 DOI: 10.1111/j.1471-4159.1983.tb11307.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The ability of catecholestrogens to induce cytosolic progestin binding sites in the hypothalamus, pituitary gland, and uterus of ovariectomised-adrenalectomised rats was demonstrated by the increase in high-affinity [3H]promegestone binding sites (KD 1.39, 0.50, and 0.54 nM, respectively) following a single subcutaneous injection (26.4 micrograms/animal) of the 3.4-dibenzoate ester of 4-hydroxyestradiol. The affinity and the time course of induction of these binding sites were very similar to those after a single injection of an equivalent dose (20 micrograms/animal) of estradiol 3-benzoate, exhibiting maximal receptor levels after 44 h. Widely differing efficacies in the induction of progestin binding sites were observed between the dibenzoate esters of 2- and 4-hydroxyestradiol. 2-Hydroxyestradiol 2,3-dibenzoate was ineffective in the pituitary gland up to a dose of 132 micrograms/animal, whereas 4-hydroxyestradiol dibenzoate was equipotent to estradiol benzoate, showing a maximal induction of progestin binding sites at single doses in the range of 13.2-26.4 micrograms/animal (equivalent to 10-20 micrograms of estradiol benzoate). As compared to the pituitary gland, the uterus was much more sensitive to the systemic administration of estrogen benzoates. At single doses in the range of 1.32-6.6 micrograms/animal (equivalent to 1-5 micrograms of estradiol benzoate), 4-hydroxyestradiol dibenzoate induced maximal levels of progestin receptors, and even 2-hydroxyestradiol dibenzoate, when given at a high dose (132.4 micrograms/animal, equivalent to 100 micrograms of estradiol benzoate), produced a slight increase in progestin binding sites.
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Ghraf R, Schneider K, Kirchhoff J, Hiemke C. Subcellular distribution of 3 alpha-hydroxysteroid dehydrogenase and antiestrogen action on androgen-metabolizing enzymes in rat pituitary gland. J Neurochem 1982; 38:876-83. [PMID: 6950028 DOI: 10.1111/j.1471-4159.1982.tb05324.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Gonadectomy of male rats led to a threefold increase of 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSDH) activity in pituitary homogenates that could be completely reversed by chronic administration of estradiol or 5 alpha-dihydrotestosterone (DHT). 3 alpha-HSDH was found to be distributed mainly between the 10,000 g and 100,000 g sediments from whole homogenates. The microsomal enzyme activity showed a substantial specificity for NADH whereas the cytosolic enzyme (100,000 g supernatant) demonstrated a slight preference for NADPH. The changes in Vmax found in homogenates following gonadectomy and gonadal steroid administration reflected changes in NADH-linked activity of the microsomal, but not the cytosolic enzyme. Estradiol-induced suppression of NADH-linked 3 alpha-HSDH activity in pituitary homogenates from gonadectomized rats of either sex was accompanied by a similar suppression of NADPH-linked 5 alpha-reductase activity and a marked decrease of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) release. In the ovariectomized rat chronic administration of nonsteroidal antiestrogens had strong estrogenic effects on 3 alpha-HSDH activity and LH release, but not on 5 alpha-reductase activity and FSH release. In the gonadectomized male rat, which was much less sensitive to intrinsic estrogenicity of the antiestrogens tested, nafoxidine completely blocked estradiol-induced suppression of 5 alpha-reductase activity and FSH release and partially antagonized suppression of LH release. The trans-isomeric, substituted triphenylethylenes, tamoxifen, and enclomiphene, as well as nitromifene (mixture of trans and cis isomers) were able partially to counteract estradiol-induced suppression of 5 alpha-reductase, but not 3 alpha-HSDH activity. It is concluded that estradiol action on pituitary 5 alpha-reductase, but not 3 alpha-HSDH activity, involves an estrogen receptor mechanism.
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Ghraf R, Schneider K, Kirchhoff J, Hiemke C. The action of 5 alpha-dihydrotestosterone and antiandrogens on the activities of 5 alpha-reductase and 3 alpha-hydroxysteroid dehydrogenase in the pituitary gland of gonadectomized rats. J Steroid Biochem 1982; 16:545-52. [PMID: 6806544 DOI: 10.1016/0022-4731(82)90077-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In gonadectomized rats of either sex s.c. administration of 5 alpha-dihydrotestosterone (DHT) reversed, in a dose dependent manner, effects brought about by gonadectomy: it decreased pituitary wet weight and serum levels of LH and FSH and suppressed microsomal enzyme activities involved in testosterone and progesterone metabolism in the pituitary gland, NADPH-linked 5 alpha-reductase and NADH-linked 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSDH). Concomitantly administered nonsteroidal antiandrogen, flutamide (5 mg/day), antagonized some of the suppressive effects induced by a 14-day treatment of gonadectomized rats with high dose (1 mg/day) of DHT. It completely blocked DHT action on pituitary 5 alpha-reductase activity in the female rat and, in the male, inhibition was found to be 30-35%. In male, but not female rats, it completely blocked DHT suppression of serum FSH level whereas it slightly, but significantly inhibited DHT suppression of serum LH in rats of either sex. However, flutamide did not prevent DHT suppression of pituitary wet weight or NADH-linked 3 alpha-HSDH activity. Concomitantly administered progestational antiandrogen, cyproterone acetate (5 mg/day), inhibited DHT-induced weight increase of seminal vesicles by 50-55% and completely blocked the weight decrease of pituitary gland but did not antagonize DHT suppression of serum gonadotropins or pituitary enzyme activities. The results obtained with flutamide suggest that DHT-induced suppression of pituitary NADPH-linked 5 alpha-reductase, but not NADH-linked 3 alpha-HSDH activity, might involve an androgen receptor mechanism.
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Kirchhoff J, Hornung E, Ghraf R, Ball P, Knuppen R. Interactions of catecholestrogens with cytoplasmic and nuclear estrogen receptors in rat pituitary gland and hypothalamus. J Neurochem 1981; 37:1540-7. [PMID: 6278079 DOI: 10.1111/j.1471-4159.1981.tb06325.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The affinity of a series of catecholestrogens for 7S cytoplasmic receptor proteins from hypothalamus and pituitary gland of ovariectomised rats was assessed in vitro by a competitive charcoal binding assay at 4 degrees C. The equilibrium dissociation constants (Ki) of catecholestrogens 4-hydroxyestradiol, 4-hydroxyethynylestradiol, 2-hydroxyestradiol, 2-hydroxyethynylestradiol, and 4-hydroxyestrone were of the same order (Ki: 0.3-0.6 nM) as those of estradiol and ethnylestradiol (Ki: 0.1 nM). Methylation of 2-hydroxyestradiol led to a substantial loss of binding affinity. Tritium-labelled receptor complexes were demonstrated in KCl extracts of purified nuclei from pituitary and hypothalamic tissue 1 h after intravenous injection of 0.1 mCi tritiated 2- or 4-hydroxyestradiol. These macromolecular complexes sedimented in the 5-6S region of 5-20% (w/v) sucrose gradients containing 0.4 M-KCl. Further evidence for the translocation of estrogen receptors by catecholestrogens into the nuclei of rat pituitary and hypothalamus was the increase in nuclear receptor concentrations, measured by exchange assay, 1 h after the intraperitoneal injection of 0.1 mg unlabelled catecholestrogen. Administration of 4-hydroxyestradiol and 4-hydroxyethynylestradiol increased nuclear receptor concentrations to the same maximal levels as those following application of the same dose of estradiol or ethynylestradiol, whereas the respective 2-hydroxylated compounds exhibited only 60-70% of the maximal translocating capacity. The in vivo translocating capacities of the various catecholestrogens tested at this dose correlated well with their binding affinities for cytosol receptors determined in vitro.
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Rousseau GG, Quivy JI, Kirchhoff J, Bui XH, Devis R. Nonsteroidal compounds which bind epididymal androgen-binding protein but not the androgen receptor. Nature 1980; 284:458-9. [PMID: 6965770 DOI: 10.1038/284458a0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Rousseau GG, Kirchhoff J, Formstecher P, Lustenberger P. 17 beta-carboxamide steroids are a new class of glucocorticoid antagonists. Nature 1979; 279:158-60. [PMID: 35753 DOI: 10.1038/279158a0] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Kirchhoff J, Soffie M, Rousseau GG. Differences in the steroid-binding site specificities of rat prostate androgen receptors and epididymal androgen-binding protein (ABP). J Steroid Biochem 1979; 10:487-97. [PMID: 459499 DOI: 10.1016/0022-4731(79)90209-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Kastendieck E, Künzel W, Kirchhoff J. [The action of Th 1165 a metabolic acidosis of the fetus during the period of expulsion. A contribution to the question of intra-uterine re-animation (author's transl)]. Z Geburtshilfe Perinatol 1974; 178:439-43. [PMID: 4156448] [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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