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Beaulieu-Genest L, Chrétien D, Maltais F, Pelletier K, Parent JG, Lacasse Y. Self-administered prescriptions of oral steroids and antibiotics in chronic obstructive pulmonary disease: are we doing more harm than good? Chron Respir Dis 2016; 4:143-7. [PMID: 17711913 DOI: 10.1177/1479972307079512] [Citation(s) in RCA: 9] [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] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Patients with chronic obstructive pulmonary disease (COPD) are often given a prescription for a short course of oral steroids and antibiotics for self-administration during an acute exacerbation. The main objective of this study was to determine the impact of such prescriptions on medical care utilization, and steroids and antibiotics intake. This retrospective cohort study included patients with moderate to severe COPD participating in a self-management programme. We compared the number of unplanned medical visits (including hospitalizations) and the utilization of systemic steroids (number of short courses, number of days on treatment) and antibiotics (number of treatments) over a period of six months following registration to the programme in patients who received such a prescription and those who did not. Data were collected from hospital and community pharmacy files. A total of 89 patients were included; 46 received a self-administered prescription. During the study period, we found no difference between the two groups in the number of unplanned medical visits. However, we observed small but significant differences in the number of short courses of Prednisone ( P = 0.018) and antibiotics ( P = 0.006). This translated in an important difference in the number of days on steroids over the same period (`Prescription' group: 26; controls: 8; P = 0.005). Self-administered prescriptions may increase steroids and antibiotics utilization in patients with moderate to severe COPD, without reducing the number of unplanned medical visits. Chronic Respiratory Disease 2007; 4: 143—147
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Affiliation(s)
- L Beaulieu-Genest
- Centre de recherche, Centre de pneumologie, Hôpital Laval, Institut universitaire de cardiologie et de pneumologie de l'Université Laval, Québec, Canada
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2
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Habarou F, Brassier A, Rio M, Chrétien D, Monnot S, Barbier V, Barouki R, Bonnefont JP, Boddaert N, Chadefaux-Vekemans B, Le Moyec L, Bastin J, Ottolenghi C, de Lonlay P. Pyruvate carboxylase deficiency: An underestimated cause of lactic acidosis. Mol Genet Metab Rep 2014. [PMID: 28649521 PMCID: PMC5471145 DOI: 10.1016/j.ymgmr.2014.11.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [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] [Indexed: 12/30/2022] Open
Abstract
Pyruvate carboxylase (PC) is a biotin-containing mitochondrial enzyme that catalyzes the conversion of pyruvate to oxaloacetate, thereby being involved in gluconeogenesis and in energy production through replenishment of the tricarboxylic acid (TCA) cycle with oxaloacetate. PC deficiency is a very rare metabolic disorder. We report on a new patient affected by the moderate form (the American type A). Diagnosis was nearly fortuitous, resulting from the revision of an initial diagnosis of mitochondrial complex IV (C IV) defect. The patient presented with severe lactic acidosis and pronounced ketonuria, associated with lethargy at age 23 months. Intellectual disability was noted at this time. Amino acids in plasma and organic acids in urine did not show patterns of interest for the diagnostic work-up. In skin fibroblasts PC showed no detectable activity whereas biotinidase activity was normal. We had previously reported another patient with the severe form of PC deficiency and we show that she also had secondary C IV deficiency in fibroblasts. Different anaplerotic treatments in vivo and in vitro were tested using fibroblasts of both patients with 2 different types of PC deficiency, type A (patient 1) and type B (patient 2). Neither clinical nor biological effects in vivo and in vitro were observed using citrate, aspartate, oxoglutarate and bezafibrate. In conclusion, this case report suggests that the moderate form of PC deficiency may be underdiagnosed and illustrates the challenges raised by energetic disorders in terms of diagnostic work-up and therapeutical strategy even in a moderate form.
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Affiliation(s)
- F Habarou
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Necker, APHP, Paris, France.,INSERM U1124, Université Paris Descartes, Paris, France.,Service de Biochimie Métabolomique et Protéomique, Hôpital Necker, APHP, Paris, France
| | - A Brassier
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Necker, APHP, Paris, France.,Université Paris Descartes, Paris, France
| | - M Rio
- Département de Génétique, Hôpital Necker, APHP, Paris, France
| | | | - S Monnot
- Département de Génétique, Hôpital Necker, APHP, Paris, France.,IHU Imagine, UMR1163, France
| | - V Barbier
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Necker, APHP, Paris, France
| | - R Barouki
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Necker, APHP, Paris, France.,INSERM U1124, Université Paris Descartes, Paris, France.,Service de Biochimie Métabolomique et Protéomique, Hôpital Necker, APHP, Paris, France
| | - J P Bonnefont
- Département de Génétique, Hôpital Necker, APHP, Paris, France.,INSERM U781, Paris, France
| | - N Boddaert
- Service de Radiologie Pédiatrique, Hôpital Necker, APHP, Paris, France
| | - B Chadefaux-Vekemans
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Necker, APHP, Paris, France.,INSERM U1124, Université Paris Descartes, Paris, France.,Service de Biochimie Métabolomique et Protéomique, Hôpital Necker, APHP, Paris, France
| | - L Le Moyec
- INSERM U902, Université d'Evry Val d'Essonne, INSERM UBIAE U902, Boulevard François Miterrand, 91025 Evry, France
| | - J Bastin
- INSERM U1124, Université Paris Descartes, Paris, France
| | - C Ottolenghi
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Necker, APHP, Paris, France.,INSERM U1124, Université Paris Descartes, Paris, France.,Service de Biochimie Métabolomique et Protéomique, Hôpital Necker, APHP, Paris, France
| | - P de Lonlay
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Necker, APHP, Paris, France.,Université Paris Descartes, Paris, France.,INSERM U781, Paris, France
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3
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Galmiche L, Jaubert F, Sauvat F, Sarnacki S, Goulet O, Assouline Z, Vedrenne V, Lebre AS, Boddaert N, Brousse N, Chrétien D, Munnich A, Rötig A. Normal oxidative phosphorylation in intestinal smooth muscle of childhood chronic intestinal pseudo-obstruction. Neurogastroenterol Motil 2011; 23:24-9, e1. [PMID: 20879992 DOI: 10.1111/j.1365-2982.2010.01595.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Chronic intestinal pseudo-obstruction (CIPO) is a severe disease of the digestive tract motility. In pediatric population, CIPO remains of unknown origin for most patients. Chronic intestinal pseudo-obstruction is also a common feature in the course of mitochondrial oxidative phosphorylation disorders related for some patients to mutations in TYMP, POLG1, mtDNA tRNA(leu(UUR)) or tRNA(lys) genes. We hypothesized that CIPOs could be the presenting symptom of respiratory chain enzyme deficiency and thus we investigated oxidative phosphorylation in small bowel and/or colon smooth muscle of primary CIPO children. METHODS We studied eight children with CIPO and 12 pediatric controls. We collected clinical, radiological and pathological data and measured respiratory chain enzymatic activity in isolated smooth muscle of the small bowel and/or the colon. We also sequenced TYMP, POLG, mtDNA tRNA(leu(UUR)) and tRNA(lys) genes. KEY RESULTS Neither pathological nor radiological data were in favor of a mitochondrial dysfunction. No respiratory chain enzyme deficiency was detected in CIPO children. In myogenic CIPO, respiratory enzymes and citrate synthase activities were increased in small bowel and/or colon whereas no abnormality was noted in neurogenic and unclassified CIPO. Levels of enzyme activities were higher in control small bowel than in control colon muscle. Sequencing of TYMP, POLG, mtDNA tRNA(leu(UUR)) and tRNA(lys) genes and POLG gene did not reveal mutation for any of the patients. CONCLUSIONS & INFERENCES The normal enzymatic activities as the lack of radiological and genetic abnormalities indicate that, at variance with adult patients, oxidative phosphorylation deficiency is not a common cause of childhood CIPO.
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Affiliation(s)
- L Galmiche
- Department of Pathology and Tumorothèque, Faculty of Medicine, Hôpital Necker Enfants-Malades and Assistance Publique-Hôpitaux de Paris, Université Paris Descartes, Paris, France.
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4
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Valayannopoulos V, Hubert L, Benoist JF, Romano S, Arnoux JB, Chrétien D, Kaplan J, Fakhouri F, Rabier D, Rötig A, Lebre AS, Munnich A, de Keyzer Y, de Lonlay P. Multiple OXPHOS deficiency in the liver of a patient with CblA methylmalonic aciduria sensitive to vitamin B(12). J Inherit Metab Dis 2009; 32:159-62. [PMID: 19277894 DOI: 10.1007/s10545-009-1023-1] [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] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Revised: 02/04/2009] [Accepted: 02/18/2009] [Indexed: 12/11/2022]
Abstract
An adult patient with methylmalonic aciduria due to defective cobalamin synthesis (CblA) responsive to vitamin B(12) presented suddenly with severe visual impairment ascribed to optic atrophy followed by a fatal multiorgan failure and lactic acidosis but low methylmalonic acid in plasma and urine. Multiple deficiency of oxidative phosphorylation was found in the patient's liver. We suggest that patients with B(12)-sensitive methylmalonic aciduria who have a milder clinical course should be carefully monitored for long-term complications.
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Affiliation(s)
- V Valayannopoulos
- Reference Center for Inherited Metabolic Disorders, Hôpital Necker-Enfants Malades and Université Paris Descartes, 149 rue de Sèvres, 75743, Paris cedex 15, France.
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5
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Cosson MA, Touati G, Lacaille F, Valayannnopoulos V, Guyot C, Guest G, Verkarre V, Chrétien D, Rabier D, Munnich A, Benoist JF, de Keyzer Y, Niaudet P, de Lonlay P. Liver hepatoblastoma and multiple OXPHOS deficiency in the follow-up of a patient with methylmalonic aciduria. Mol Genet Metab 2008; 95:107-9. [PMID: 18676166 DOI: 10.1016/j.ymgme.2008.06.007] [Citation(s) in RCA: 22] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2008] [Accepted: 06/13/2008] [Indexed: 10/21/2022]
Abstract
A boy who was diagnosed with methylmalonic aciduria (MMA) at the age of 10 days developed persistent hepatomegaly and raised transaminases from the age of 4 years. He was subsequently diagnosed with Leigh syndrome and required a kidney transplantation for end-stage renal failure. A massive hepatoblastoma led to his death by the age of 11 years. Methylmalonyl-CoA mutase activity was undetectable on both cultured skin fibroblasts and kidney biopsy and multiple respiratory chain deficiency was demonstrated in the kidney. Mitochondrial dysfunction and/or post-transplant immunosuppressive therapy should be considered as a possible cause of liver cancer in this patient.
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Affiliation(s)
- M A Cosson
- Metabolic unit, Reference Center, Necker-Enfants Malades Hospital, University Paris Descartes, 149 rue de Sèvres, 75009 Paris, France
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6
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Romano S, Samara D, Crosnier H, Valayannopoulos V, Polak M, Chrétien D, Rötig A, Munnich A, Brauner R, de Lonlay P. Variable outcome of growth hormone administration in respiratory chain deficiency. Mol Genet Metab 2008; 93:195-9. [PMID: 17951089 DOI: 10.1016/j.ymgme.2007.09.007] [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] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Revised: 09/12/2007] [Accepted: 09/12/2007] [Indexed: 10/22/2022]
Abstract
Genetic defects of oxidative phosphorylation (OXPHOS) are known to account for a variety of neuromuscular and non-neuromuscular symptoms in childhood, including growth hormone (GH) deficiency. However GH administration for GH deficiency is controversial in OXPHOS deficiencies as GH is a mitosis-stimulator which may increase energy demand for cell proliferation. Here, we report the observation of four unrelated children with OXPHOS deficiency or bearing a mitochondrial DNA rearrangement and growth retardation, who required GH therapy. The first patient had no GH deficiency while the other three had low GH response to test stimulations. The condition of the first two patients quickly deteriorated under GH administration, GH was then stopped and subsequent clinical improvement was noted. In the other two patients, no adverse event was noted but various additional organs were involved following GH administration. In all patients, no benefit was observed concerning growth response as growth speed remained unchanged. These observations question the use of GH as a treatment of growth retardation for patients with OXPHOS deficiency.
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Affiliation(s)
- S Romano
- Department of Medical Genetics and INSERM U-781, Hôpital Necker-Enfants Malades, 149, rue de Sèvres, 75743 Paris Cedex 15, France
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7
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Abstract
The molecular mechanisms that allow elongation of the unstable microtubule lattice remain unclear. It is usually thought that the GDP-liganded tubulin lattice is capped by a small layer of GTP- or GDP-Pi-liganded molecules, the so called "GTP-cap". Here, we point-out that the elastic properties of the microtubule lattice cause a difference in stability between the elongating tubulin sheet and the completed microtubule wall. The implications of our observations for microtubule structure and dynamics are discussed.
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Affiliation(s)
- D Chrétien
- Laboratoire des Protéines Complexes, Université de Tours, 2 bis Boulevard Tonnellé, F-37032 Tours, France.
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8
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de Lonlay P, Valnot I, Barrientos A, Gorbatyuk M, Tzagoloff A, Taanman JW, Benayoun E, Chrétien D, Kadhom N, Lombès A, de Baulny HO, Niaudet P, Munnich A, Rustin P, Rötig A. A mutant mitochondrial respiratory chain assembly protein causes complex III deficiency in patients with tubulopathy, encephalopathy and liver failure. Nat Genet 2001; 29:57-60. [PMID: 11528392 DOI: 10.1038/ng706] [Citation(s) in RCA: 216] [Impact Index Per Article: 9.4] [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: 11/09/2022]
Abstract
Complex III (CIII; ubiquinol cytochrome c reductase of the mitochondrial respiratory chain) catalyzes electron transfer from succinate and nicotinamide adenine dinucleotide-linked dehydrogenases to cytochrome c. CIII is made up of 11 subunits, of which all but one (cytochrome b) are encoded by nuclear DNA. CIII deficiencies are rare and manifest heterogeneous clinical presentations. Although pathogenic mutations in the gene encoding mitochondrial cytochrome b have been described, mutations in the nuclear-DNA-encoded subunits have not been reported. Involvement of various genes has been indicated in assembly of yeast CIII (refs. 8-11). So far only one such gene, BCS1L, has been identified in human. BCS1L represents, therefore, an obvious candidate gene in CIII deficiency. Here, we report BCS1L mutations in six patients, from four unrelated families and presenting neonatal proximal tubulopathy, hepatic involvement and encephalopathy. Complementation study in yeast confirmed the deleterious effect of these mutations. Mutation of BCS1L would seem to be a frequent cause of CIII deficiency, as one-third of our patients have BCS1L mutations.
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Affiliation(s)
- P de Lonlay
- INSERM U393, Hôpital Necker-Enfants Malades, 149 rue de Sèvres, 75015 Paris
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9
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Geromel V, Kadhom N, Ceballos-Picot I, Chrétien D, Munnich A, Rötig A, Rustin P. Human cultured skin fibroblasts survive profound inherited ubiquinone depletion. Free Radic Res 2001; 35:11-21. [PMID: 11697113 DOI: 10.1080/10715760100300551] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Beside its role in electron transfer in the mitochondrial respiratory chain, ubiquinone is known to prevent lipid peroxidation and DNA damage by trapping cellular free radicals. Thanks to its antioxidant properties, ubiquinone may represent an important factor controlling both necrotic and apoptotic processes. We have investigated the consequences of a profound inherited ubiquinone depletion on cultured skin fibroblasts of a patient presenting with encephalomyopathy. Interestingly, cell respiration, mitochondrial oxidation of various substrates, and cell growth of ubiquinone-deficient fibroblasts were only partially decreased. Moreover, these cells did not apparently overproduce superoxide anions or lipoperoxides. Finally, apoptosis did not increase as compared to control, even after serum deprivation. These observations suggest that ubiquinone may not play a major role in the antioxidant defenses of cultured fibroblasts and that its role in controlling oxidative stress and apoptosis may greatly vary across cell types, especially as not all tissues were equally affected in the patient despite the widespread ubiquinone depletion in vivo.
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Affiliation(s)
- V Geromel
- Unité de Recherches sur les Handicaps Génétiques de l'Enfant (INSERM U393) Hôpital Necker-Enfants Malades, 149, rue de Sèvres, 75743 Paris, France
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10
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Gauthier-Villars M, Landrieu P, Cormier-Daire V, Jacquemin E, Chrétien D, Rötig A, Rustin P, Munnich A, de Lonlay P. Respiratory chain deficiency in Alpers syndrome. Neuropediatrics 2001; 32:150-2. [PMID: 11521212 DOI: 10.1055/s-2001-16614] [Citation(s) in RCA: 33] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Alpers syndrome is a progressive encephalopathy of early onset, characterized by rapid and severe developmental delay, intractable seizures and liver involvement in a previously healthy child. Here, we report on respiratory chain enzyme deficiency in the liver of four unrelated children presenting with epileptic encephalopathy and liver involvement diagnosed as Alpers syndrome. Interestingly, oxidative phosphorylation in skeletal muscle was normal in 4/4 and blood and CSF lactate in 3/4 patients. Liver involvement had a late clinical onset in patients with previously isolated epileptic encephalopathy. Based on these observations, we suggest 1. to give consideration to respiratory chain deficiency in the diagnosis of severe epileptic encephalopathy in childhood, even when no clinical or biological evidence of liver involvement or lactic acidosis is noted, and 2. to investigate the respiratory chain in a needle biopsy of the liver in children with epileptic encephalopathy prior to valproate administration if biochemical indications for respiratory chain disease or hepatic disturbance are noted, as this drug is believed to occasionally trigger hepatic failure and fatal outcome.
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Affiliation(s)
- M Gauthier-Villars
- Department of Medical Genetics and INSERM U-393, Hôpital Necker-Enfants Malades, Paris, France
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11
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Faivre L, Cormier-Daire V, Chrétien D, Christoph von Kleist-Retzow J, Amiel J, Dommergues M, Saudubray JM, Dumez Y, Rötig A, Rustin P, Munnich A. Determination of enzyme activities for prenatal diagnosis of respiratory chain deficiency. Prenat Diagn 2000; 20:732-7. [PMID: 11015702 DOI: 10.1002/1097-0223(200009)20:9<732::aid-pd916>3.0.co;2-#] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Genetic counselling and prenatal diagnosis are major issues of mitochondrial respiratory chain deficiency, especially as these conditions are largely untreatable. In the absence of known mitochondrial or nuclear gene mutations, measurement of respiratory chain enzyme activities represents the only possibility to prevent recurrence of the disease in affected families. We carried out enzymatic prenatal diagnosis in 21 pregnancies from 10 unrelated couples using uncultured choriocytes and/or amniocytes. Twelve babies were born and are healthy, seven pregnancies were discontinued early on because of an enzyme deficiency detected prenatally. In two cases, a fetus which appeared normal after early and/or late prenatal diagnosis, turned out to be affected. We conclude that a deficient enzyme activity is indicative of recurrence, but a normal result at 10 weeks of gestation does not give conclusive evidence as to the outcome of the pregnancy. We therefore suggest the following procedure: (1) a choriocentesis or an amniocentesis in early pregnancy when the proband expresses the disease in cultured skin fibroblasts; (2) a second amniocentesis at 28 weeks' gestation should be offered to avoid false negative results due to a possible late expression of the disease, in combination with: (3) a careful and repeated ultrasound survey for detection of growth failure in the third trimester; (4) prenatal diagnosis should not be performed in case of late onset clinical symptoms in the proband; and (5) parents should be aware of the possibility of false negative results. Prenatal diagnosis should not be proposed for a complex I deficiency as this enzyme activity cannot be accurately measured in fetal cells.
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Affiliation(s)
- L Faivre
- Unité de Recherche sur les Handicaps Génétiques de l'Enfant, INSERM U-393 and Département de Génétique, Hôpital Necker Enfants-Malades, Paris, France
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12
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Abstract
The polarity of microtubules is reflected in cryo-electron microscope images and in three-dimensional reconstructions [Chrétien et al., 1996: Structure 4:1031-1040; Sosa and Milligan, 1996: J. Mol. Biol. 260:743-755]. This paper shows how the directionality of the moiré patterns and the shape of the tubulin subunits are related. Microtubules observed by cryo-electron microscopy show an arrowhead moiré pattern that points toward the plus end of microtubules with a right-handed protofilament skew and toward the minus end of microtubules with a left-handed protofilament skew. On the other hand, three-dimensional reconstructions of microtubules observed from the plus end reveal a radial counterclockwise slew of the tubulin subunits. We show how these polar features are related and present unambiguous rules for determining the polarity on longitudinal and axial views of microtubules.
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Affiliation(s)
- H Sosa
- Department of Cell Biology MB25, The Scripps Research Institute, La Jolla, California, USA
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13
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Abstract
Tubulin assembles to form a range of structures that differ by their protofilament and monomer helix-start numbers. The microtubule lattice is believed to accommodate these different configurations by skewing the protofilaments so that the lateral interactions between tubulin subunits are maintained. Here, we present the characterization of 14 types of microtubules, including six novel ones, through an extensive analysis of microtubules assembled in vitro from pure tubulin. Although the six new types represented only 1 % of the total length of the population examined ( approximately 17 mm), they define the limits of microtubule structure and assembly. Protofilament skewing is restricted to within +/-2 degrees. Outside this range, the restoring force induced by the skewed protofilaments is compensated by a longitudinal shift (less than +/-0.2 nm) between adjacent protofilaments. Configurations with theoretical protofilament skew angles larger than +/-4 degrees or that necessitate larger modifications of the microtubule surface lattice were not observed. Analysis of the microtubule types distribution reveals that it is sharply peaked around the less skewed conformations. These results indicate that both the flexibility of the protofilaments and the strength of their lateral interactions restrict the range of structures assembled. They also demonstrate that growing microtubules can occasionally switch into energetically unfavorable configurations, a behavior that may account for the stochastic nature of catastrophes.
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Affiliation(s)
- D Chrétien
- Equipe ATIPE, UPRES-A 6026 CNRS, Université de Rennes 1, Campus de Beaulieu Bt 13, Rennes, 35042, France.
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14
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de Lonlay-Debeney P, von Kleist-Retzow JC, Hertz-Pannier L, Peudenier S, Cormier-Daire V, Berquin P, Chrétien D, Rötig A, Saudubray JM, Baraton J, Brunelle F, Rustin P, Van Der Knaap M, Munnich A. Cerebral white matter disease in children may be caused by mitochondrial respiratory chain deficiency. J Pediatr 2000; 136:209-14. [PMID: 10657827 DOI: 10.1016/s0022-3476(00)70103-x] [Citation(s) in RCA: 25] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Several mitochondrial diseases are known to occasionally involve the cerebral white matter, namely Leigh syndrome, Kearns-Sayre syndrome, and MELAS syndrome, but in these cases the major finding is alteration in the basal ganglia and brainstem. Here we report on severe diffuse white matter involvement and respiratory chain enzyme deficiency or mitochondrial DNA rearrangement in 5 unrelated families. It is interesting that white matter lesions were the only abnormal neuroradiologic feature in 3 of the 5 families, and multiple small cyst-like white matter lesions were found in 2 of 5 probands. Respiratory chain deficiency should be considered in the diagnosis of severe white matter involvement in childhood.
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Affiliation(s)
- P de Lonlay-Debeney
- Département de Génétique and INSERM U-393, Service de Radiologie Pédiatrique, Département de Pédiatrie, Hôpital Necker-Enfants Malades, Paris, France
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15
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de Lonlay-Debeney P, Edery P, Cormier-Daire V, Parfait B, Chrétien D, Rötig A, Romero N, Saudubray JM, Munnich A, Rustin P. Respiratory chain deficiency presenting as recurrent myoglobinuria in childhood. Neuropediatrics 1999; 30:42-4. [PMID: 10222461 DOI: 10.1055/s-2007-973456] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [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: 10/21/2022]
Abstract
Myoglobinuria is an abnormal urinary excretion of myoglobin due to an acute destruction of skeletal muscle fibres. Several metabolic diseases are known to account for myoglobinuria including defects of glycolysis and fatty acid oxidation. Here, we report on respiratory chain enzyme deficiency in three unrelated children with recurrent episodes of myoglobinuria and muscle weakness (complex I: one patient, complex IV: two patients). All three patients had generalized hyporeflexia during attacks, a feature which is not commonly reported in other causes of rhabdomyolysis. Studying respiratory chain enzyme activities in cultured skin fibroblasts might help diagnosing this condition, especially when acute rhabdomyolysis precludes skeletal muscle biopsy during and immediately after episodes of myoglobinuria.
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16
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Parfait B, de Lonlay P, von Kleist-Retzow JC, Cormier-Daire V, Chrétien D, Rötig A, Rabier D, Saudubray JM, Rustin P, Munnich A. The neurogenic weakness, ataxia and retinitis pigmentosa (NARP) syndrome mtDNA mutation (T8993G) triggers muscle ATPase deficiency and hypocitrullinaemia. Eur J Pediatr 1999; 158:55-8. [PMID: 9950309 DOI: 10.1007/s004310051009] [Citation(s) in RCA: 36] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
UNLABELLED Based on the study of three unrelated families, we report what we believe to be the first in vivo evidence of muscle ATPase deficiency in individuals carrying the neurogenic weakness, ataxia and retinitis pigmentosa (NARP) syndrome mtDNA mutation (T8993G). Since plasma citrulline was consistently low in 4/5 patients, we suggest that the NARP mutation caused complex V deficiency in the small intestine as well, thus reducing the availability of mitochondrial ATP required for citrulline synthesis. CONCLUSION We suggest giving consideration to hypocitrullinaemia as a hallmark of the neurogenic weakness, ataxia and retinitis pigmentosa syndrome mutation and more generally of impaired oxidative phosphorylation in the small intestine in vivo.
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Affiliation(s)
- B Parfait
- Département de Génétique et INSERM U393, Hôpital Necker-Enfants Malades, Paris, France
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17
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Chrétien D, Flyvbjerg H, Fuller SD. Limited flexibility of the inter-protofilament bonds in microtubules assembled from pure tubulin. Eur Biophys J 1998; 27:490-500. [PMID: 9760730 DOI: 10.1007/s002490050159] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The superposition of the regular arrangement of tubulin subunits in microtubules gives rise to moiré patterns in cryo-electron micrographs. The moiré period can be predicted from the dimensions of the tubulin subunits and their arrangement in the surface lattice. Although the average experimental moiré period is usually in good agreement with the theoretical one, there is variation both within and between microtubules. In this study, we addressed the origin of this variability. We examined different possibilities, including artefacts induced by the preparation of the vitrified samples, and variations of the parameters that describe the microtubule surface lattice. We show that neither flattening nor bending of the microtubules, nor changes in the subunit dimensions, can account for the moiré period variations observed in 12 and 14 protofilament microtubules. These can be interpreted as slight variations, in the range -0.5 A to +0.9 A, of the lateral interactions between tubulin subunits in adjacent protofilaments. These results indicate that the inter-protofilament bonds are precisely maintained in microtubules assembled in vitro from pure tubulin. The fact that the moiré period is not affected by bending indicates that the local interactions between tubulin subunits are sufficiently stiff to accommodate large deformations of the microtubule wall.
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Affiliation(s)
- D Chrétien
- Cell Biology Programme, European Molecular Biology Laboratory, Heidelberg, Germany.
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18
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Abstract
Electron micrographs of tips of growing and shrinking microtubules are analyzed and interpreted. The many shapes observed are all consistent with a simple mechanical model, a flexible tube with competing intrinsic curvatures. Observations are also consistent with growing and shrinking microtubules having the same intrinsic curvature for protofilaments, the one observed in oligomers peeling off shrinking microtubules. If this is so, the lateral bonds between protofilaments are responsible for the difference between shapes of tips on growing and shrinking microtubules.
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Affiliation(s)
- I M Jánosi
- Höchstleistungsrechenzentrum (HRLZ), Forschungszentrum Jülich, Germany
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19
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Müller-Reichert T, Chrétien D, Severin F, Hyman AA. Structural changes at microtubule ends accompanying GTP hydrolysis: information from a slowly hydrolyzable analogue of GTP, guanylyl (alpha,beta)methylenediphosphonate. Proc Natl Acad Sci U S A 1998; 95:3661-6. [PMID: 9520422 PMCID: PMC19892 DOI: 10.1073/pnas.95.7.3661] [Citation(s) in RCA: 190] [Impact Index Per Article: 7.3] [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: 02/06/2023] Open
Abstract
Microtubules are dynamic polymers that interconvert between periods of slow growth and fast shrinkage. The energy driving this nonequilibrium behavior comes from the hydrolysis of GTP, which is required to destabilize the microtubule lattice. To understand the mechanism of this destabilization, cryo-electron microscopy was used to compare the structure of the ends of shrinking microtubules assembled in the presence of either GTP or the slowly hydrolyzable analogue guanylyl (alpha,beta)methylenediphosphonate (GMPCPP). Depolymerization was induced by cold or addition of calcium. With either nucleotide, we have observed curled oligomers at the ends of shrinking microtubules. However, GDP oligomers were consistently more curved than GMPCPP oligomers. This difference in curvature between depolymerizing GDP and GMPCPP protofilaments suggests that GTP hydrolysis is accompanied by an increase in curvature of the protofilaments, thereby destabilizing the lateral interactions between tubulin subunits in the microtubule lattice.
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Affiliation(s)
- T Müller-Reichert
- Cell Biology Program, European Molecular Biology Laboratory, Meyerhofstrasse 1, Postfach 1022.09, D-69117, Heidelberg, Germany.
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20
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Abstract
The absence of detailed in vitro studies leaves the molecular events involved in the centrosome cycle poorly characterized. Most earlier studies have employed electron microscopy of thin or thick sections of cells. Here we have analyzed the structure of centrosomes isolated from nonsynchronized human lymphoblastic KE37 cells using cryoelectron microscopy of vitrified specimens. The centrosomes were classified into five categories depending on the number of centrioles (one or two), the respective orientation of the two centrioles in a pair (orthogonal or disoriented), and the presence or absence of appendages at the distal extremity of the centrioles (referred to as mature and immature, respectively). A detailed analysis of the centriole dimensions in these categories allowed us to reconstruct the centrosome cycle in KE37 cells. Our results suggest that centriole assembly is completed only when the mother centriole of an immature orthogonal pair separates from its daughter in preparation to centrosome duplication. Our study shows that an in vitro approach based on cryoelectron microscopy of vitrified specimens can be used to obtain detailed structural information on the centrosome cycle.
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Affiliation(s)
- D Chrétien
- European Molecular Biology Laboratory, Heidelberg, Postfach 1022.09, D-69117, Germany.
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21
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Rötig A, Lehnert A, Chrétien D, Rustin P, Gubler MC, Munnich A, Niaudet P. Atteinte rénale au cours des cytopathies mitochondriales. Med Sci (Paris) 1997. [DOI: 10.4267/10608/296] [Citation(s) in RCA: 1] [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: 11/30/2022] Open
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22
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Cormier-Daire V, Rustin P, Rötig A, Chrétien D, Le Merrer M, Belli D, Le Goff A, Hubert P, Ricour C, Munnich A. Craniofacial anomalies and malformations in respiratory chain deficiency. Am J Med Genet 1996; 66:457-63. [PMID: 8989468 DOI: 10.1002/(sici)1096-8628(19961230)66:4<457::aid-ajmg15>3.0.co;2-t] [Citation(s) in RCA: 32] [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] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We report on facial anomalies including round face, high forehead, flat philtrum, apparently low-set ears, and short neck in 4 unrelated patients with mitochondrial respiratory enzyme deficiency. Pre- and postnatal growth retardation with microcephaly, brachydactyly, and hypoplasia of distal and middle phalanges was present in all 4 cases. The diagnosis of respiratory chain deficiency was confirmed by enzymatic and molecular studies. The combination of facial anomalies, prenatal growth failure, and malformations is suggestive of antenatal expression of the disease, and raises the question of the part that respiratory chain deficiencies play in human malformations.
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Affiliation(s)
- V Cormier-Daire
- INSERM U393 Département de Génétique, Hôpital des Enfants Malades, Paris, France
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23
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Abstract
BACKGROUND Microtubules are tubular polymers of tubulin dimers, which are arranged head-to-tail in protofilaments that run lengthwise along the microtubules, giving them an overall structural polarity. Many of the functions of microtubules depend on this polarity, including directed intracellular transport and chromosome segregation during mitosis. The determination of microtubule polarity for lengthwise views of microtubules observed by electron microscopy has not previously been possible. Here, we present methods for directly determining the polarity of individual microtubules imaged by cryo-electron microscopy. RESULTS When observed in vitreous ice by cryo-electron microscopy, microtubules with skewed protofilaments show arrowhead moiré patterns. We have used centrosome nucleated microtubules to relate the directionality of the moiré patterns to microtubule polarity. We show that the arrowheads point towards the plus end of microtubules with protofilaments having a right-handed skew, and towards the minus end of microtubules with protofilaments having a left-handed skew. We describe two methods for determining the handedness of the protofilament skew. The first method uses two or more tilted views. The second method involves analysis of the diffraction patterns of the microtubule images. CONCLUSIONS It is now possible to determine directly the polarity of in vitro assembled microtubules from cryo-electron micrographs. This will be helpful in a number of types of studies, including studies of the three-dimensional structure of microtubules interacting with motor proteins, as knowledge of the polarity of the microtubule is essential to understand motor directionality.
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Affiliation(s)
- D Chrétien
- Structural Biology Programme, European Molecular Biology Laboratory, Meyerhofstrasse 1, Postfach 10.2209, D-69117 Heidelberg, Germany.
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24
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Abstract
Observation of microtubule growth at different rates by cryo-electron microscopy reveals that the ends range from blunt to long, gently curved sheets. The mean sheet length increases with the growth rate while the width of the distributions increases with the extent of assembly. The combination of a concentration dependent growth rate of the tubulin sheet with a variable closure rate of the microtubule cylinder, results in a model in which stochastic fluctuations in sheet length and tubulin conformation confine GTP-tubulins to microtubule ends. We propose that the variability of microtubule growth rate observed by video microscopy (Gildersleeve, R. F., A. R. Cross, K. E. Cullen, A. P. Fagen, and R. C. Williams. 1992. J. Biol. Chem. 267: 7995-8006, and this study) is due to the variation in the rate of cylinder closure. The curvature of the sheets at the end of growing microtubules and the small oligomeric structures observed at the end of disassembling microtubules, indicate that tubulin molecules undergo conformational changes both during assembly and disassembly.
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Affiliation(s)
- D Chrétien
- European Molecular Biology Laboratory, Heidelberg, Germany
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25
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Hyman AA, Chrétien D, Arnal I, Wade RH. Structural changes accompanying GTP hydrolysis in microtubules: information from a slowly hydrolyzable analogue guanylyl-(alpha,beta)-methylene-diphosphonate. J Biophys Biochem Cytol 1995; 128:117-25. [PMID: 7822409 PMCID: PMC2120325 DOI: 10.1083/jcb.128.1.117] [Citation(s) in RCA: 198] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We have used cryoelectron microscopy to try to understand the structural basis for the role of GTP hydrolysis in destabilizing the microtubule lattice. We have measured a structural difference introduced into microtubules by replacing GTP with guanylyl-(alpha,beta)-methylene-diphosphonate (GMPCPP). In a stable GMPCPP microtubule lattice, the moiré patterns change and the tubulin subunits increase in size by 1.5 A. This information provides a clue to the role of hydrolysis in inducing the structural change at the end of a microtubule during the transition from a growing to a shrinking phase.
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Affiliation(s)
- A A Hyman
- Cell Biology Program, European Molecular Biology Laboratory, Heidelberg, Germany
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26
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Abstract
We demonstrate that the scanning tunneling microscope can be used to obtain information about arrangement of tubulin subunits in the microtubule wall. Long rows of subunits with a periodicity of 3.8 +/- 0.4 nm were clearly visible in the images of microtubules. The separation between the rows of subunits was 4.8 +/- 0.4 nm. Close inspection of two images revealed another periodicity of 7.8 +/- 0.4 nm in the contour levels of the protofilaments. This indicates that alpha and beta tubulin monomers can be resolved. In these areas the monomers were arranged according to a ‘B-type’ lattice. Scanning tunneling microscope images confirm that the lateral contacts between tubulin monomers in adjacent protofilaments are compatible with a three-start, left-handed helix model. This study demonstrates that scanning tunneling microscopy can give direct information on the structure and organization of macromolecular assemblies and can complement the classical methods of electron microscopy and X-ray scattering.
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Affiliation(s)
- M Maaloum
- European Molecular Biology Laboratory, Heidelberg, Germany
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27
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Affiliation(s)
- R H Wade
- Institut de Biologie Structurale, Grenoble, France
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28
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Abstract
We have used cryo-electron microscopy of vitrified specimens to study microtubules assembled both from three cycle purified tubulin (3x-tubulin) and in cell free extracts of Xenopus eggs. In vitro assembled 3x-tubulin samples have a majority of microtubules with 14 protofilaments whereas in cell extracts most microtubules have 13 protofilaments. Microtubule polymorphism was observed in both cases. The number of protofilaments can change abruptly along individual microtubules usually by single increments but double increments also occur. For 3x-tubulin, increasing the magnesium concentration decreases the proportion of 14 protofilament microtubules and decreases the average separation between transitions in these microtubules. Protofilament discontinuities may correspond to dislocation-like defects in the microtubule surface lattice.
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Affiliation(s)
- D Chrétien
- Laboratoire de Biologie Structurale, CEA, Grenoble, France
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29
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Bourgeron T, Chrétien D, Rötig A, Munnich A, Rustin P. Prenatal diagnosis of cytochrome c oxidase deficiency in cultured amniocytes is hazardous. Prenat Diagn 1992; 12:548-9. [PMID: 1325051 DOI: 10.1002/pd.1970120614] [Citation(s) in RCA: 7] [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: 12/26/2022]
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30
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Sidi D, Le Bidois J, Piéchaud JF, Da Cruz E, Marchal C, Gournay V, Kachaner J, Rustin P, Chrétien D, Munnich A. [Enzymatic activities of the mitochondrial respiratory chain in child cardiomyopathies. 34 cases prospectively studied by endomyocardial biopsy]. Arch Mal Coeur Vaiss 1992; 85:541-6. [PMID: 1530392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The arguments in favour of mitochondrial pathology of certain childhood cardiomyopathies (multi tissue involvement, lactic acidosis, histochemical abnormalities of skeletal muscle) are indirect and may be absent in isolated cardiomyopathy. The authors therefore set up a prospective study of enzyme activity of the mitochondrial respiratory chain directly by endomyocardial biopsy. Fifty children aged 2 months to 16 years were included. Thirty four had cardiomyopathy which was dilated and hypokinetic with thin walls in 21 cases, restrictive in 2 cases, and hypertrophic in 11 cases; the remaining 16 children had either normal hearts (13 catheterised for other reasons) or myocardial hypertrophy due to pulmonary or aortic stenosis (3 cases). Both ventricles were evaluated in 3 cases; macro-surgical biopsies were obtained in 6 cases and skeletal muscle biopsy was obtained in 9 cases. The results indicate the method to be reliable with no difference between the micro and macro biopsies. The absolute values of enzyme activity were too variable to serve as quantitative parameters but some ratios of activity were remarkably stable and allowed a qualitative assessment which was all the more accurate when identical values were obtained in the myocardium, skeletal muscle and liver. The mitochondrial respiration was independent of ventricular pressures and of the type (right or left) of ventricle. Enzyme activity was nearly always normal in dilated cardiomyopathy (20/21) which suggests that it was unaffected by dilatation of the heart and by abnormal myocardial contractility. The results could be normal in myocardial hypertrophy and in valvular stenosis and in over half the cases of hypertrophic cardiomyopathy.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- D Sidi
- Département de pédiatrie, Inserm U12, hôpital Necker-Enfants Malades, Paris
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31
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Abstract
The in vitro polymerisation of tubulin is a remarkable example of protein self-assembly in that several closely related microtubule structures coexist on the polymerisation plateau. Unfixed and unstained in vitro assembled microtubules were observed in vitreous ice by cryo-electron microscopy. New results are reported that considerably extend previous observations [47]. In ice, microtubule images have a distinctive contrast related to the number and skew of the protofilaments. The microtubules observed have from twelve to seventeen protofilaments. Comparison with thin sections of pelleted material allows a direct identification of images from microtubules with thirteen, fourteen and fifteen protofilaments. A surface lattice accommodation mechanism, previously proposed to explain how variable numbers of protofilaments can be incorporated into the basic thirteen protofilament structure, is described in detail. Our new experimental results are shown to be in overall agreement with the theoretical predictions. Only thirteen protofilament microtubules have unskewed protofilaments, this was confirmed by observations on axoneme fragments. The results imply that the microtubule surface lattice is based on a mixed packing which combines features of the standard A and B lattices.
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Affiliation(s)
- D Chrétien
- Laboratoire de Biologie Structurale, CEA, Grenoble, France
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32
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Abstract
Frozen-hydrated specimens of microtubules assembled in vitro were observed by cryoelectron microscopy. Specimens were of both pure tubulin, and of microtubule protein isolated by three cycles of assembly and disassembly. It is shown that the characteristic image contrast of individual microtubules allows the microtubule protofilament number to be determined unambiguously. Microtubules with 13, 14 and 15 protofilaments are observed to coexist in specimens prepared under various assembly conditions. Confirmation of these results is obtained by observations of thin sections of pelleted samples fixed and stained using the glutaraldehyde/tannic acid technique. Images of individual microtubules show both characteristic contrast profiles across their width and typical variations of these profiles along their length. The profiles across the images indicate the protofilament number of the microtubule. The lengthwise variations indicate how the protofilaments are aligned with respect to the microtubule axis giving what has previously been called a supertwist. In 13 protofilament microtubules the protofilaments are paraxial. In 14 and 15 protofilament microtubules, the protofilaments are skewed with respect to the microtubule axis. The skew is greater for the 15 protofilament case than for 14 protofilaments. The skew allows the extra protofilaments to be accommodated by the surface lattice. These results should also be relevant to situations in vivo.
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Affiliation(s)
- R H Wade
- Laboratoire de Biologie Structurale, CEA et URA 1333 CNRS, Grenoble, France
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