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Araya-Secchi R, Bugge K, Seiffert P, Petry A, Haxholm GW, Lindorff-Larsen K, Pedersen SF, Arleth L, Kragelund BB. The prolactin receptor scaffolds Janus kinase 2 via co-structure formation with phosphoinositide-4,5-bisphosphate. eLife 2023; 12:84645. [PMID: 37232489 DOI: 10.7554/elife.84645] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 05/24/2023] [Indexed: 05/27/2023] Open
Abstract
Class 1 cytokine receptors transmit signals through the membrane by a single transmembrane helix to an intrinsically disordered cytoplasmic domain that lacks kinase activity. While specific binding to phosphoinositides has been reported for the prolactin receptor (PRLR), the role of lipids in PRLR signalling is unclear. Using an integrative approach combining NMR spectroscopy, cellular signalling experiments, computational modelling and simulation, we demonstrate co-structure formation of the disordered intracellular domain of the human PRLR, the membrane constituent phosphoinositide-4,5-bisphosphate (PI(4,5)P2) and the FERM-SH2 domain of the Janus kinase 2 (JAK2). We find that the complex leads to accumulation of PI(4,5)P2 at the transmembrane helix interface and that mutation of residues identified to interact specifically with PI(4,5)P2 negatively affects PRLR-mediated activation of signal transducer and activator of transcription 5 (STAT5). Facilitated by co-structure formation, the membrane-proximal disordered region arranges into an extended structure. We suggest that the co-structure formed between PRLR, JAK2 and PI(4,5)P2 locks the juxtamembrane disordered domain of the PRLR in an extended structure, enabling signal relay from the extracellular to the intracellular domain upon ligand binding. We find that the co-structure exists in different states which we speculate could be relevant for turning signalling on and off. Similar co-structures may be relevant for other non-receptor tyrosine kinases and their receptors.
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Affiliation(s)
- Raul Araya-Secchi
- Facultad de Ingenieria Arquitectura y Diseño, Universidad San Sebastian, Santiago, Chile
| | - Katrine Bugge
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Pernille Seiffert
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Amalie Petry
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Gitte W Haxholm
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | | | | | - Lise Arleth
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
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2
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Chhabra Y, Seiffert P, Gormal RS, Vullings M, Lee CMM, Wallis TP, Dehkhoda F, Indrakumar S, Jacobsen NL, Lindorff-Larsen K, Durisic N, Waters MJ, Meunier FA, Kragelund BB, Brooks AJ. Tyrosine kinases compete for growth hormone receptor binding and regulate receptor mobility and degradation. Cell Rep 2023; 42:112490. [PMID: 37163374 DOI: 10.1016/j.celrep.2023.112490] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 03/07/2023] [Accepted: 04/24/2023] [Indexed: 05/12/2023] Open
Abstract
Growth hormone (GH) acts via JAK2 and LYN to regulate growth, metabolism, and neural function. However, the relationship between these tyrosine kinases remains enigmatic. Through an interdisciplinary approach combining cell biology, structural biology, computation, and single-particle tracking on live cells, we find overlapping LYN and JAK2 Box1-Box2-binding regions in GH receptor (GHR). Our data implicate direct competition between JAK2 and LYN for GHR binding and imply divergent signaling profiles. We show that GHR exhibits distinct mobility states within the cell membrane and that activation of LYN by GH mediates GHR immobilization, thereby initiating its nanoclustering in the membrane. Importantly, we observe that LYN mediates cytokine receptor degradation, thereby controlling receptor turnover and activity, and this applies to related cytokine receptors. Our study offers insight into the molecular interactions of LYN with GHR and highlights important functions for LYN in regulating GHR nanoclustering, signaling, and degradation, traits broadly relevant to many cytokine receptors.
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Affiliation(s)
- Yash Chhabra
- Frazer Institute, The University of Queensland, Woolloongabba, QLD 4102, Australia; The University of Queensland, Institute for Molecular Bioscience, St. Lucia, QLD 4072, Australia; Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21204, USA.
| | - Pernille Seiffert
- Structural Biology and NMR Laboratory (SBiNLab) and REPIN, Department of Biology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Rachel S Gormal
- The Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Manon Vullings
- The University of Queensland, Institute for Molecular Bioscience, St. Lucia, QLD 4072, Australia
| | | | - Tristan P Wallis
- The Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Farhad Dehkhoda
- Frazer Institute, The University of Queensland, Woolloongabba, QLD 4102, Australia
| | - Sowmya Indrakumar
- Structural Biology and NMR Laboratory (SBiNLab) and REPIN, Department of Biology, University of Copenhagen, 2200 Copenhagen, Denmark; Structural Biology and NMR Laboratory & Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Nina L Jacobsen
- Structural Biology and NMR Laboratory (SBiNLab) and REPIN, Department of Biology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Kresten Lindorff-Larsen
- Structural Biology and NMR Laboratory & Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Nela Durisic
- The Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Michael J Waters
- The University of Queensland, Institute for Molecular Bioscience, St. Lucia, QLD 4072, Australia
| | - Frédéric A Meunier
- The Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia; School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory (SBiNLab) and REPIN, Department of Biology, University of Copenhagen, 2200 Copenhagen, Denmark.
| | - Andrew J Brooks
- Frazer Institute, The University of Queensland, Woolloongabba, QLD 4102, Australia; The University of Queensland, Institute for Molecular Bioscience, St. Lucia, QLD 4072, Australia.
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Pesce F, Newcombe EA, Seiffert P, Tranchant EE, Olsen JG, Grace CR, Kragelund BB, Lindorff-Larsen K. Assessment of models for calculating the hydrodynamic radius of intrinsically disordered proteins. Biophys J 2023; 122:310-321. [PMID: 36518077 PMCID: PMC9892621 DOI: 10.1016/j.bpj.2022.12.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 11/18/2022] [Accepted: 12/09/2022] [Indexed: 12/15/2022] Open
Abstract
Diffusion measurements by pulsed-field gradient NMR and fluorescence correlation spectroscopy can be used to probe the hydrodynamic radius of proteins, which contains information about the overall dimension of a protein in solution. The comparison of this value with structural models of intrinsically disordered proteins is nonetheless impaired by the uncertainty of the accuracy of the methods for computing the hydrodynamic radius from atomic coordinates. To tackle this issue, we here build conformational ensembles of 11 intrinsically disordered proteins that we ensure are in agreement with measurements of compaction by small-angle x-ray scattering. We then use these ensembles to identify the forward model that more closely fits the radii derived from pulsed-field gradient NMR diffusion experiments. Of the models we examined, we find that the Kirkwood-Riseman equation provides the best description of the hydrodynamic radius probed by pulsed-field gradient NMR experiments. While some minor discrepancies remain, our results enable better use of measurements of the hydrodynamic radius in integrative modeling and for force field benchmarking and parameterization.
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Affiliation(s)
- Francesco Pesce
- Structural Biology and NMR Laboratory, The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Estella A Newcombe
- Structural Biology and NMR Laboratory, The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Pernille Seiffert
- Structural Biology and NMR Laboratory, The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Emil E Tranchant
- Structural Biology and NMR Laboratory, The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Johan G Olsen
- Structural Biology and NMR Laboratory, The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Christy R Grace
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory, The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
| | - Kresten Lindorff-Larsen
- Structural Biology and NMR Laboratory, The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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Seiffert P, Bugge K, Nygaard M, Haxholm GW, Martinsen JH, Pedersen MN, Arleth L, Boomsma W, Kragelund BB. Orchestration of signaling by structural disorder in class 1 cytokine receptors. Cell Commun Signal 2020; 18:132. [PMID: 32831102 PMCID: PMC7444064 DOI: 10.1186/s12964-020-00626-6] [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] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/08/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Class 1 cytokine receptors (C1CRs) are single-pass transmembrane proteins responsible for transmitting signals between the outside and the inside of cells. Remarkably, they orchestrate key biological processes such as proliferation, differentiation, immunity and growth through long disordered intracellular domains (ICDs), but without having intrinsic kinase activity. Despite these key roles, their characteristics remain rudimentarily understood. METHODS The current paper asks the question of why disorder has evolved to govern signaling of C1CRs by reviewing the literature in combination with new sequence and biophysical analyses of chain properties across the family. RESULTS We uncover that the C1CR-ICDs are fully disordered and brimming with SLiMs. Many of these short linear motifs (SLiMs) are overlapping, jointly signifying a complex regulation of interactions, including network rewiring by isoforms. The C1CR-ICDs have unique properties that distinguish them from most IDPs and we forward the perception that the C1CR-ICDs are far from simple strings with constitutively bound kinases. Rather, they carry both organizational and operational features left uncovered within their disorder, including mechanisms and complexities of regulatory functions. CONCLUSIONS Critically, the understanding of the fascinating ability of these long, completely disordered chains to orchestrate complex cellular signaling pathways is still in its infancy, and we urge a perceptional shift away from the current simplistic view towards uncovering their full functionalities and potential. Video abstract.
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Affiliation(s)
- Pernille Seiffert
- REPIN, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Katrine Bugge
- REPIN, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Mads Nygaard
- REPIN, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Gitte W. Haxholm
- REPIN, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Jacob H. Martinsen
- REPIN, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Martin N. Pedersen
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen Ø, Denmark
| | - Lise Arleth
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen Ø, Denmark
| | - Wouter Boomsma
- Department of Computer Science, University of Copenhagen, Universitetsparken 1, 2100 Copenhagen Ø, Denmark
| | - Birthe B. Kragelund
- REPIN, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
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5
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Pedersen CP, Seiffert P, Brakti I, Bugge K. Production of Intrinsically Disordered Proteins for Biophysical Studies: Tips and Tricks. Methods Mol Biol 2020; 2141:195-209. [PMID: 32696358 DOI: 10.1007/978-1-0716-0524-0_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Intrinsically disordered proteins (IDPs) have no single, fixed tertiary structure, yet they take on many vital functions in biology. In recent years, considerable effort has been put into the structural characterization of their conformational ensembles, to understand the link between the transient, short- and long-range organizations of IDPs and their functions. Such biophysical studies require substantial amounts of pure protein, representing a major bottleneck in the studies of IDPs. However, the unique physicochemical properties resulting from their compositional bias may be exploited for simple yet effective purification strategies. In this chapter, we provide tips and tricks for IDP production and describe the most important analyses to carry out before bringing an IDP of interest to the laboratory. We outline four purification protocols utilizing the unique properties of IDPs as well as some commonly encountered challenges and pitfalls.
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Affiliation(s)
- Christian Parsbæk Pedersen
- Structural Biology and NMR Laboratory and the Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen N, Denmark
| | - Pernille Seiffert
- Structural Biology and NMR Laboratory and the Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen N, Denmark
| | - Inna Brakti
- Structural Biology and NMR Laboratory and the Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen N, Denmark
| | - Katrine Bugge
- Structural Biology and NMR Laboratory and the Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen N, Denmark.
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6
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Breuling T, Tschiedel E, Große-Lordemann A, Hünseler C, Schmidt C, Niemann F, Dettmer P, Freymann H, von Noorden C, Wallot M, Heister P, Heitmann F, Rothoeft T, Schürmann U, Backendorf A, Heldmann M, Schubert E, Nuńez FB, Seiffert P, Felderhoff-Müser U, Dohna-Schwake C. Septic shock in children in an urban area in Western Germany--outcome, risk factors for mortality and infection epidemiology. Klin Padiatr 2015; 227:61-5. [PMID: 25751679 DOI: 10.1055/s-0034-1398690] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND Only sparse data exist about children with septic shock in Europe. The present study aimed to evaluate demographics, treatment, outcome and risk factors for mortality in Western Germany. PATIENTS Children with septic shock aged 2 months to 17 years. METHODS In a multi-center retrospective study of 20 children's hospitals data were obtained and analyzed by chart review. Risk factors for mortality were identified and assessed by multivariate regression analysis. RESULTS Overall mortality in 83 cases with septic shock was 25% (21 patients). Significant risk factors were high PRISM III score, low pH, low arterial systolic blood pressure, presence of disseminated intravascular coagulation and extent of multi-organ failure, but not lactate (p=0.05) and base excess (p=0.065). Mortality in hospitals which treated 10 or more patients (category 1) was 17% and increased to 22% in hospitals which treated 3-6 patients (category 2). In hospitals with only 1 or 2 patients (category 3) mortality rate was 61% (p<0.01 when compared to category 1 or 2). A stepwise increase was also seen in the severely sick patients according to PRISM III (>19): category 1: 23%, category 2: 40%, category 3: 62.5% (p<0.05 for comparison of category 1 and 3). Multivariate analysis of significant risk factors revealed low number of treated patients as the only individual risk factor for mortality. CONCLUSION Mortality from pediatric septic shock in an urban area in Western Germany is high. Disease severity and treatment in a department with few cases were associated with increased mortality.
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Affiliation(s)
- T Breuling
- Pediatrics I, University of Duisburg-Essen, Essen, Germany
| | - E Tschiedel
- Pediatrics I, University of Duisburg-Essen, Essen, Germany
| | | | - C Hünseler
- Department of Neonatology and Pediatric Intensive Care, Children's Hospital, University of Cologne, Cologne, Germany
| | - C Schmidt
- Department of Pediatrics, St. Vincenz Hospital, Dinslaken, Germany
| | - F Niemann
- Department of Pediatrics, Bergmannsheil und Kinderklinik GmbH, Gelsenkirchen, Germany
| | - P Dettmer
- Department of Pediatrics, St.-Agnes-Hospital, Bocholt, Germany
| | - H Freymann
- Department of Pediatrics, Florence-Nightingale-Krankenhaus, Düsseldorf, Germany
| | - C von Noorden
- Department of Pediatrics, Evangelisches Krankenhaus, Oberhausen, Germany
| | - M Wallot
- Department of Pediatrics, Bethanien Krankenhaus, Moers, Germany
| | - P Heister
- Centre for Child and Adolescent Health, HELIOS Klinikum Krefeld, Krefeld, Germany
| | - F Heitmann
- Department of Pediatrics, Community Hospital Dortmund, Dortmund, Germany
| | - T Rothoeft
- Department of Pediatrics, St. Josephs Hospital, University of Bochum, Bochum, Germany
| | - U Schürmann
- Department of Neonatology and Pediatric Intensive Care Medicine, University Hospital Witten/Herdecke, Datteln, Germany
| | - A Backendorf
- Department of Neonatology, Elisabeth-Krankenhaus, Essen, Germany
| | - M Heldmann
- Department of Pediatrics, Helios Klinikum, Wuppertal, Germany
| | - E Schubert
- Department of Pediatrics, Klinikum Niederberg, Velbert, Germany
| | - F B Nuńez
- Department of Pediatrics, Klinikum Duisburg, Duisburg, Germany
| | - P Seiffert
- Department of Pediatrics, Helios Klinikum, Duisburg, Germany
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7
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Berlemann B, Bürücüoglu T, Seiffert P, Gong M, Simaite D, Raile K. Neonataler Diabetes bei heterozygoter KCNJ11-Mutation Val59Met: Frühe Glibenclamidtherapie führt zu normaler, psychomotorischer Entwicklung (im Alter von 17 Monaten). DIABETOL STOFFWECHS 2013. [DOI: 10.1055/s-0033-1341727] [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: 10/26/2022]
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8
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Heyer CM, Mueller KM, Seiffert P, Nicolas V, Rieger CHL, Nuesslein TG. Pulmonary sarcoidosis in a 14-year-old boy diagnosed by low-dose CT-guided transthoracic lung biopsy. Pediatr Pulmonol 2006; 41:269-74. [PMID: 16429435 DOI: 10.1002/ppul.20354] [Citation(s) in RCA: 9] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Pulmonary sarcoidosis is a rare disease in the pediatric age group, characterized by the presence of epitheloid-cell granulomas. In stage 3 sarcoidosis, pulmonary infiltrates without hilar lymphadenopathy occur. Definitive diagnosis requires a histopathological specimen, which might be difficult to obtain by transbronchial biopsy. Multidetector computed tomography (MDCT)-guided transthoracic lung biopsy (TLB) is a well-established procedure in adults, but has only rarely been applied in children.A 14-year-old boy was admitted to hospital for evaluation of a chronic systemic disease with severe pulmonary manifestation. All investigations, including bronchosopy and bronchoalveolar lavage with microbiological and virological testing, had been negative. MDCT-guided TLB was performed on a 16-section scanner with a low-dose protocol (single slices, 120 kV, 20 mAs), using a 16-gauge biopsy device. The total effective dose was 0.4 mSv for the biopsy procedure. Histopathological examination revealed multiple epitheloid-cell granulomas with giant cells in the absence of microbiological or virological abnormalities. A diagnosis of stage 3 pulmonary sarcoidosis was made and systemic anti-inflammatory therapy was administered, which led to complete remission within weeks. MDCT-guided TLB can be a valuable instrument in assessing pulmonary manifestations of pediatric sarcoidosis, enabling precise histopathological diagnosis and adequate therapy. The use of low-dose protocols can substantially reduce radiation exposure without relevant loss of image information. MDCT-guided lung biopsy should be considered prior to open-lung surgery in selected patients with unclear pulmonary disease.
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Affiliation(s)
- C M Heyer
- Institute of Diagnostic Radiology, Interventional Radiology, and Nuclear Medicine, Berufgenossenschaftliche Kliniken Bergmannsheil, Ruhr-University of Bochum, Bochum, Germany.
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9
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Baethmann M, Wendel U, Hoffmann GF, Göhlich-Ratmann G, Kleinlein B, Seiffert P, Blom H, Voit T. Hydrocephalus internus in two patients with 5,10-methylenetetrahydrofolate reductase deficiency. Neuropediatrics 2000; 31:314-7. [PMID: 11508552 DOI: 10.1055/s-2000-12947] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Hydrocephalus internus (HCI) of all four ventricles in association with early neurological abnormalities is described as the presenting symptom in two patients with 5,10-methylenetetrahydrofolate reductase (MTHFR) deficiency. Decreased activity of MTHFR leads to reduction of 5-methyltetrahydrofolate, the main methyl donor for methionine synthesis necessary for synthesis of S-adenosyl-methionine (SAM). Demyelination in MTHFR deficiency has been attributed to low SAM levels in the brain. The biochemical hallmarks of the disorder are hyperhomocystinemia, homocystinuria and low levels of plasma methionine. Hydrocephalus internus requiring neurosurgical intervention has to our knowledge not been reported as a presenting feature of homocystinuria due to deficiency of MTHFR so far. The surprising finding of HCI of all four ventricles in MTHFR deficiency must be kept in mind when evaluating patients with hydrocephalus of unknown origin.
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Affiliation(s)
- M Baethmann
- Department of Pediatrics, University Hospital, Essen, Germany
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10
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Abstract
The case of a 4-year-old girl suffering from a severe bronchopneumonia of the left lower lobe is presented. Microscopically no cartilage was found in the resected lobe distal to the lobar bronchus. The case is unusual because a congenital lobar emphysema associated with an aplasia of bronchial cartilage has to be considered as well as secondary cartilage destruction due to chronic relapsing inflammations.
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Affiliation(s)
- R J Elfeldt
- Department of General and Thoracic Surgery, University of Kiel, Germany
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11
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Wessel A, Seiffert P. [Effects of amrinone in myocardial insufficiency following heart surgery in children]. Monatsschr Kinderheilkd 1989; 137:712-5. [PMID: 2608071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
11 infants and children with severe congestive heart failure after cardiac surgery were treated with Amrinone. Cardiac and circulatory effects were monitored by quantitative echocardiography and blood pressure measurements. Within 1 day after the initial dose ventricular ejection fractions (EF) increased. Left ventricle: EF = 0.35 +/- 0.06 to EF = 0.49 +/- 0.06; right ventricle: EF = 0.30 +/- 0.12 to EF = 0.56 +/- 0.12. Vascular resistance dropped from R = 1527 +/- 517 dyn.s.cm-5.m2 to R = 1071 +/- 399 dyn.s.cm-5.m2. Blood pressure and heart rate remained almost unchanged. It is concluded, that Amrinone acts as a positive inotropic and vasodilating drug with the potential for effective treatment in children where conventional therapy has failed.
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Affiliation(s)
- A Wessel
- Abteilung Kinderkardiologie und Biomedizinische Technik, Christian-Albrechts-Universität Kiel
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12
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Abstract
A 17-year old boy with hypertrophic obstructive cardiomyopathy (HOCM) developed repeated short runs of self terminating ventricular tachycardia 12 hours after starting oral verapamil, which was substituted for propranolol therapy. It is suggested that alterations in sympathetic tone induced by changing from a beta-blocker to a calcium antagonist might have increased myocardial irritability thus favouring genesis of severe ventricular arrhythmias. Verapamil is often considered to be more effective than propranolol in the treatment of HOCM. However, if propranolol is replaced by verapamil one has to take account of the possibility of serious arrhythmias as demonstrated by our case.
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