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Siebert JR, Smith KJ, Cox LL, Glass IA, Cox TC. Microtomographic analysis of lower urinary tract obstruction. Pediatr Dev Pathol 2013; 16:405-14. [PMID: 23977847 PMCID: PMC3965709 DOI: 10.2350/13-08-1359-oa.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Prenatal obstruction of the lower urinary tract may result in megacystis, with subsequent development of hydroureter, hydronephrosis, and renal damage. Oligo- or anhydramnios, pulmonary hypoplasia, and prune belly syndrome are lethal consequences. Causes and mechanisms responsible for obstruction remain unclear but might be clarified by anatomic study at autopsy. To this end, we employed 2 methods of tomographic imaging-optical projection tomography and contrast-enhanced microCT scanning-to elucidate the anatomy of the intact urinary bladder and urethra in 10 male fetuses with lower urinary tract obstruction. Images were compared with those from 9 age-matched controls. Three-dimensional images, rotated and sectioned digitally in multiple planes, permitted thorough examination while preserving specimens for later study. Both external and internal features of the bladder and urethra were demonstrated; small structures (ie, urethral crest, verumontanum, prostatic utricle, ejaculatory ducts) were seen in detail. Types of obstruction consisted of urethral atresia (n = 5), severe urethral stenosis (n = 2), urethral diaphragm (n = 2), or physical kinking (n = 1); classic (Young type I) posterior urethral valves were not encountered. Traditional light microscopy was then used to verify tomographic findings. The prostate gland was hypoplastic or absent in all cases; in 1, prostatic tissue was displaced inferior to the verumontanum. Findings support previous views that dissection may produce valve-like artifacts (eg, bisection of an obstructing diaphragm) and that deformation of an otherwise normal urethra may result in megacystis. The designation "posterior urethral valves" should not be used as a generic expression of urethral obstruction unless actual valves are demonstrated.
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Yamamura B, Cox TC, Heddaya B, Flake NM, Johnson JD, Paranjpe A. Comparing Canal Transportation and Centering Ability of EndoSequence and Vortex Rotary Files by Using Micro–Computed Tomography. J Endod 2012; 38:1121-5. [DOI: 10.1016/j.joen.2012.04.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 04/25/2012] [Accepted: 04/27/2012] [Indexed: 11/25/2022]
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Munot P, Saunders DE, Milewicz DM, Regalado ES, Ostergaard JR, Braun KP, Kerr T, Lichtenbelt KD, Philip S, Rittey C, Jacques TS, Cox TC, Ganesan V. A novel distinctive cerebrovascular phenotype is associated with heterozygous Arg179 ACTA2 mutations. Brain 2012; 135:2506-14. [PMID: 22831780 DOI: 10.1093/brain/aws172] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mutations in the ACTA2 gene lead to diffuse and diverse vascular diseases; the Arg179His mutation is associated with an early onset severe phenotype due to global smooth muscle dysfunction. Cerebrovascular disease associated with ACTA2 mutations has been likened to moyamoya disease, but appears to have distinctive features. This study involved the analysis of neuroimaging of 13 patients with heterozygous missense mutations in ACTA2 disrupting Arg179. All patients had persistent ductus arteriosus and congenital mydriasis, and variable presentation of pulmonary hypertension, bladder and gastrointestinal problems associated with this mutation. Distinctive cerebrovascular features were dilatation of proximal internal carotid artery, occlusive disease of terminal internal carotid artery, an abnormally straight course of intracranial arteries, and absent basal 'moyamoya' collaterals. Patterns of brain injury supported both large and small vessel disease. Key differences from moyamoya disease were more widespread arteriopathy, the combination of arterial ectasia and stenosis and, importantly, absence of the typical basal 'moyamoya' collaterals. Evaluation of previously published cases suggests some of these features are also seen in the ACTA2 mutations disrupting Arg258. The observation that transition from dilated to normal/stenotic arterial calibre coincides with where the internal carotid artery changes from an elastic to muscular artery supports the hypothesis that abnormal smooth muscle cell proliferation caused by ACTA2 mutations is modulated by arterial wall components. Patients with persistent ductus arteriosus or congenital mydriasis with a label of 'moyamoya' should be re-evaluated to ensure the distinctive neuroimaging features of an ACTA2 mutation have not been overlooked. This diagnosis has prognostic and genetic implications, and mandates surveillance of other organ systems, in particular the aorta, to prevent life-threatening aortic dissection.
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Quina LA, Kuramoto T, Luquetti DV, Cox TC, Serikawa T, Turner EE. Deletion of a conserved regulatory element required for Hmx1 expression in craniofacial mesenchyme in the dumbo rat: a newly identified cause of congenital ear malformation. Dis Model Mech 2012; 5:812-22. [PMID: 22736458 PMCID: PMC3484864 DOI: 10.1242/dmm.009910] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hmx1 is a homeodomain transcription factor expressed in the developing eye, peripheral ganglia, and branchial arches of avian and mammalian embryos. Recent studies have identified a loss-of-function allele at the HMX1 locus as the causative mutation in the oculo-auricular syndrome (OAS) in humans, characterized by ear and eye malformations. The mouse dumbo (dmbo) mutation, with similar effects on ear and eye development, also results from a loss-of-function mutation in the Hmx1 gene. A recessive dmbo mutation causing ear malformation in rats has been mapped to the chromosomal region containing the Hmx1 gene, but the nature of the causative allele is unknown. Here we show that dumbo rats and mice exhibit similar neonatal ear and eye phenotypes. In midgestation embryos, dumbo rats show a specific loss of Hmx1 expression in neural-crest-derived craniofacial mesenchyme (CM), whereas Hmx1 is expressed normally in retinal progenitors, sensory ganglia and in CM, which is derived from mesoderm. High-throughput resequencing of 1 Mb of rat chromosome 14 from dmbo/dmbo rats, encompassing the Hmx1 locus, reveals numerous divergences from the rat genomic reference sequence, but no coding changes in Hmx1. Fine genetic mapping narrows the dmbo critical region to an interval of ∼410 kb immediately downstream of the Hmx1 transcription unit. Further sequence analysis of this region reveals a 5777-bp deletion located ∼80 kb downstream in dmbo/dmbo rats that is not apparent in 137 other rat strains. The dmbo deletion region contains a highly conserved domain of ∼500 bp, which is a candidate distal enhancer and which exhibits a similar relationship to Hmx genes in all vertebrate species for which data are available. We conclude that the rat dumbo phenotype is likely to result from loss of function of an ultraconserved enhancer specifically regulating Hmx1 expression in neural-crest-derived CM. Dysregulation of Hmx1 expression is thus a candidate mechanism for congenital ear malformation, most cases of which remain unexplained.
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Rolfe SM, Shapiro LG, Cox TC, Maga AM, Cox LL. A landmark-free framework for the detection and description of shape differences in embryos. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2011:5153-6. [PMID: 22255499 DOI: 10.1109/iembs.2011.6091276] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
This paper introduces a new method to quantify and characterize shape changes during early facial development without the use of landmarks. Landmarks are traditionally used in morphometric analysis, but very few can be identified reliably across all stages of embryonic development. This method uses deformable registration to produce a dense vector field describing the point correspondences between two images. Low and mid-level features are extracted from the deformable vector field to find regions of organized differences that are biologically relevant. These methods are shown to detect regions of difference when evaluated on chick embryo images warped with small magnitude deformations in regions critical to midfacial development.
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Neradilek MB, Polissar NL, Einstein DR, Glenny RW, Minard KR, Carson JP, Jiao X, Jacob RE, Cox TC, Postlethwait EM, Corley RA. Branch-based model for the diameters of the pulmonary airways: accounting for departures from self-consistency and registration errors. Anat Rec (Hoboken) 2012; 295:1027-44. [PMID: 22528468 PMCID: PMC5581196 DOI: 10.1002/ar.22476] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 03/06/2012] [Indexed: 11/08/2022]
Abstract
We examine a previously published branch-based approach for modeling airway diameters that is predicated on the assumption of self-consistency across all levels of the tree. We mathematically formulate this assumption, propose a method to test it and develop a more general model to be used when the assumption is violated. We discuss the effect of measurement error on the estimated models and propose methods that take account of error. The methods are illustrated on data from MRI and CT images of silicone casts of two rats, two normal monkeys, and one ozone-exposed monkey. Our results showed substantial departures from self-consistency in all five subjects. When departures from self-consistency exist, we do not recommend using the self-consistency model, even as an approximation, as we have shown that it may likely lead to an incorrect representation of the diameter geometry. The new variance model can be used instead. Measurement error has an important impact on the estimated morphometry models and needs to be addressed in the analysis.
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White R, Ho G, Schmidt S, Scheffer IE, Fischer A, Yendle SC, Bienvenu T, Nectoux J, Ellaway CJ, Darmanian A, Tong X, Cloosterman D, Bennetts B, Kalra V, Fullston T, Gecz J, Cox TC, Christodoulou J. Cyclin-Dependent Kinase-Like 5 (CDKL5) Mutation Screening in Rett Syndrome and Related Disorders. Twin Res Hum Genet 2012; 13:168-78. [DOI: 10.1375/twin.13.2.168] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
AbstractRett syndrome (RTT) is a severe neurodevelopmental disorder affecting females almost exclusively and is characterized by a wide spectrum of clinical manifestations. Mutations in the X-linked methyl-CpG-binding protein 2 (MECP2) gene have been found in up to 95% of classical RTT cases and a lesser proportion of atypical cases. Recently, mutations in another X-linked gene, CDKL5 (cyclin-dependent kinase-like 5) have been found to cause atypical RTT, in particular the early onset seizure (Hanefeld variant) and one female with autism. In this study we screened several cohorts of children for CDKL5 mutations, totaling 316 patients, including individuals with a clinical diagnosis of RTT but who were negative for MECP2 mutations (n = 102), males with X-linked mental retardation (n = 9), patients with West syndrome (n = 52), patients with autism (n = 59), patients with epileptic encephalopathy (n = 33), patients with Aicardi syndrome (n = 7) and other patients with intellectual disability with or without seizures (n = 54). In all, seven polymorphic variations and four de novo mutations (c.586C>T [p.S196L]; c.58G>C [p.G20R]; c.2504delC [p.P835fs]; deletion of exons 1 - 3) were identified, and in all instances of the latter the clinical phenotype was that of an epileptic encephalopathy. These results suggest that pathogenic CDKL5 mutations are unlikely to be identified in the absence of severe early-onset seizures and highlight the importance of screening for large intragenic and whole gene deletions.
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Luquetti DV, Heike CL, Hing AV, Cunningham ML, Cox TC. Microtia: epidemiology and genetics. Am J Med Genet A 2012; 158A:124-39. [PMID: 22106030 PMCID: PMC3482263 DOI: 10.1002/ajmg.a.34352] [Citation(s) in RCA: 237] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 09/12/2011] [Indexed: 12/26/2022]
Abstract
Microtia is a congenital anomaly of the ear that ranges in severity from mild structural abnormalities to complete absence of the ear, and can occur as an isolated birth defect or as part of a spectrum of anomalies or a syndrome. Microtia is often associated with hearing loss and patients typically require treatment for hearing impairment and surgical ear reconstruction. The reported prevalence varies among regions, from 0.83 to 17.4 per 10,000 births, and the prevalence is considered to be higher in Hispanics, Asians, Native Americans, and Andeans. The etiology of microtia and the cause of this wide variability in prevalence are poorly understood. Strong evidence supports the role of environmental and genetic causes for microtia. Although some studies have identified candidate genetic variants for microtia, no causal genetic mutation has been confirmed. The application of novel strategies in developmental biology and genetics has facilitated elucidation of mechanisms controlling craniofacial development. In this paper we review current knowledge of the epidemiology and genetics of microtia, including potential candidate genes supported by evidence from human syndromes and animal models. We also discuss the possible etiopathogenesis in light of the hypotheses formulated to date: Neural crest cells disturbance, vascular disruption, and altitude.
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Fairfield H, Gilbert GJ, Barter M, Corrigan RR, Curtain M, Ding Y, D'Ascenzo M, Gerhardt DJ, He C, Huang W, Richmond T, Rowe L, Probst FJ, Bergstrom DE, Murray SA, Bult C, Richardson J, Kile BT, Gut I, Hager J, Sigurdsson S, Mauceli E, Di Palma F, Lindblad-Toh K, Cunningham ML, Cox TC, Justice MJ, Spector MS, Lowe SW, Albert T, Donahue LR, Jeddeloh J, Shendure J, Reinholdt LG. Mutation discovery in mice by whole exome sequencing. Genome Biol 2011; 12:R86. [PMID: 21917142 PMCID: PMC3308049 DOI: 10.1186/gb-2011-12-9-r86] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 08/04/2011] [Accepted: 09/14/2011] [Indexed: 01/18/2023] Open
Abstract
We report the development and optimization of reagents for in-solution, hybridization-based capture of the mouse exome. By validating this approach in a multiple inbred strains and in novel mutant strains, we show that whole exome sequencing is a robust approach for discovery of putative mutations, irrespective of strain background. We found strong candidate mutations for the majority of mutant exomes sequenced, including new models of orofacial clefting, urogenital dysmorphology, kyphosis and autoimmune hepatitis.
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Wiseman A, Cox TC, Paranjpe A, Flake NM, Cohenca N, Johnson JD. Efficacy of sonic and ultrasonic activation for removal of calcium hydroxide from mesial canals of mandibular molars: a microtomographic study. J Endod 2011; 37:235-8. [PMID: 21238809 DOI: 10.1016/j.joen.2010.11.019] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 11/12/2010] [Accepted: 11/12/2010] [Indexed: 10/18/2022]
Abstract
BACKGROUND The purpose of this study was to use micro-computed tomography (micro-CT) scanning to evaluate the efficacy of sonic and passive ultrasonic irrigation (PUI) on calcium hydroxide (Ca[OH](2)) removal and to measure the volume and percentage of Ca(OH)(2) remaining in the root canal system. METHODOLOGY The root canals of 46 extracted human mandibular molar teeth were prepared with rotary instruments and randomly assigned to two experimental groups (n = 40) as well as positive and negative controls (n = 6). In each experimental group, 20 teeth were assigned to each irrigation protocol, sonic or passive ultrasonic irrigation. All experimental teeth and the positive controls were filled with Ca(OH)(2), whereas the negative control teeth did not receive Ca(OH)(2). All teeth were scanned using micro-CT scanning to determine the dressing volume. After 7 days, the Ca(OH)(2) was removed in the experimental groups using rotary instrumentation only, and the teeth were again scanned using micro-CT scanning to calculate volume and percentage of Ca(OH)(2) removed. Positive control teeth were not subjected to rotary instrumentation. Experimental samples were then irrigated using either sonic or passive ultrasonic and the volume of remaining Ca(OH)(2) was calculated using micro-CT. RESULTS Remnants of Ca(OH)(2) were found in all experimental groups. No Ca(OH)(2) was found in the negative controls, whereas a mean of 8.7 mm(3) of Ca(OH)(2) was recorded in the positive controls. Rotary plus passive ultrasonic irrigation removed significantly more Ca(OH)(2) (85.7%) than rotary plus sonic irrigation (71.5%) (p < 0.001). CONCLUSIONS The combination of rotary instrumentation and passive ultrasonic activation for 3 periods of 20 seconds results in significantly lower amounts of Ca(OH)(2) remnants in the canal compared with sonic irrigation.
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Purushothaman R, Cox TC, Maga AM, Cunningham ML. Facial suture synostosis of newborn Fgfr1(P250R/+) and Fgfr2(S252W/+) mouse models of Pfeiffer and Apert syndromes. ACTA ACUST UNITED AC 2011; 91:603-9. [PMID: 21538817 DOI: 10.1002/bdra.20811] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 01/31/2011] [Accepted: 02/22/2011] [Indexed: 01/20/2023]
Abstract
Apert and Pfeiffer syndromes are hereditary forms of craniosynostosis characterized by midfacial hypoplasia and malformations of the limbs and skull. A serious consequence of midfacial hypoplasia in these syndromes is respiratory compromise due to airway obstruction. In this study, we have evaluated Fgfr1(P250R/+) and Fgfr2(S252W/+) mouse models of these human conditions to study the pathogenesis of midfacial hypoplasia. Our histologic and micro-CT evaluation revealed premature synostosis of the premaxillary-maxillary, nasal-frontal, and maxillary-palatine sutures of the face and dysplasia of the premaxilla, maxilla, and palatine bones. These midfacial abnormalities were detected in the absence of premature ossification of the cranial base at postnatal day 0. Our results indicate that midfacial hypoplasia is not secondary to premature cranial base ossification but rather primary synostosis of facial sutures. Birth Defects Research (Part A), 2011.
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Slavotinek AM, Baranzini SE, Schanze D, Labelle-Dumais C, Short KM, Chao R, Yahyavi M, Bijlsma EK, Chu C, Musone S, Wheatley A, Kwok PY, Marles S, Fryns JP, Maga AM, Hassan MG, Gould DB, Madireddy L, Li C, Cox TC, Smyth I, Chudley AE, Zenker M. Manitoba-oculo-tricho-anal (MOTA) syndrome is caused by mutations in FREM1. J Med Genet 2011; 48:375-82. [PMID: 21507892 DOI: 10.1136/jmg.2011.089631] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Manitoba-oculo-tricho-anal (MOTA) syndrome is a rare condition defined by eyelid colobomas, cryptophthalmos and anophthalmia/microphthalmia, an aberrant hairline, a bifid or broad nasal tip, and gastrointestinal anomalies such as omphalocele and anal stenosis. Autosomal recessive inheritance had been assumed because of consanguinity in the Oji-Cre population of Manitoba and reports of affected siblings, but no locus or cytogenetic aberration had previously been described. METHODS AND RESULTS This study shows that MOTA syndrome is caused by mutations in FREM1, a gene previously mutated in bifid nose, renal agenesis, and anorectal malformations (BNAR) syndrome. MOTA syndrome and BNAR syndrome can therefore be considered as part of a phenotypic spectrum that is similar to, but distinct from and less severe than, Fraser syndrome. Re-examination of Frem1(bat/bat) mutant mice found new evidence that Frem1 is involved in anal and craniofacial development, with anal prolapse, eyelid colobomas, telecanthus, a shortened snout and reduced philtral height present in the mutant mice, similar to the human phenotype in MOTA syndrome. CONCLUSIONS The milder phenotypes associated with FREM1 deficiency in humans (MOTA syndrome and BNAR syndrome) compared to that resulting from FRAS1 and FREM2 loss of function (Fraser syndrome) are also consistent with the less severe phenotypes resulting from Frem1 loss of function in mice. Together, Fraser, BNAR and MOTA syndromes constitute a clinically overlapping group of FRAS-FREM complex diseases.
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Ganesan V, Cox TC, Gunny R. Abnormalities of cervical arteries in children with arterial ischemic stroke. Neurology 2011; 76:166-71. [PMID: 21220720 DOI: 10.1212/wnl.0b013e318205d4d5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES To describe the frequency of cervical arterial abnormalities in children with acute arterial ischemic stroke (AIS), to examine predictors of this, and to characterize observed abnormalities in terms of specific diagnoses. METHODS Review of case notes of children with AIS (2002-2009) and analysis of their neuroimaging for infarct location and presence, location, and nature of arterial disease. Logistic regression analysis was used to examine the relationship between age, infarct distribution, number of risk factors, antecedent trauma, and the presence of cervical arterial disease. RESULTS Sixty children (31 boys, median age 5 years 3 months) were included. Cerebral infarction was in the anterior circulation only in 50 (25 purely subcortical), the posterior circulation only in 9, and both distributions in 1. Cervical arterial abnormalities occurred in 15/60 (25%) and intracranial abnormalities in 26. There was no significant relationship between the presence of an abnormality in the intracranial and cervical magnetic resonance angiogram (Fisher exact test, p = 0.29). Cervical arterial disease was categorized as definite arterial dissection in 2 cases, probable arterial dissection in 7, nonspecific occlusive arteriopathy in 5, and a migrated vaso-occlusive device in 1. In logistic regression analysis, infarction in the distribution of the posterior circulation significantly predicted the presence of a cervical arterial abnormality (p = 0.04); age, number of risk factors, and antecedent trauma were not predictive. CONCLUSION Cervical arteriopathy is common in children with AIS, especially in posterior circulation infarction. The cervical vasculature should be imaged in all children with AIS.
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Cox TC, Pearl JP, Ritter EM. Rives-Stoppa incisional hernia repair combined with laparoscopic separation of abdominal wall components: a novel approach to complex abdominal wall closure. Hernia 2010; 14:561-7. [PMID: 20661611 DOI: 10.1007/s10029-010-0704-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 06/26/2010] [Indexed: 11/27/2022]
Abstract
BACKGROUND The Rives-Stoppa incisional hernia repair is the gold standard for mesh repair of complex incisional hernias. The risk of infection can be reduced if fascia is closed over the prosthetic mesh. Fascial closure in large defects may require extensive dissection and can result in devascularization of the overlying skin and denervation of the abdominal wall musculature. Laparoscopic components separation minimizes these risks while facilitating anterior fascial closure. The combined technique of Rives-Stoppa repair augmented by laparoscopic separation of abdominal wall components has not previously been reported. METHODS We retrospectively reviewed our initial experience with this combined technique for incisional hernia repair. A Rives-Stoppa incisional hernia repair is performed with mesh placed in the retromuscular position. If the anterior fascia cannot be closed, a laparoscopic separation of abdominal wall components is performed to facilitate fascial closure without creation of skin flaps. RESULTS Six patients were identified. Three patients developed hernias following laparotomy from severe injuries sustained during combat. The other patients included hernia after esophagectomy, retroperitoneal liposarcoma resection, and complicated diverticulitis. Average defect size was 270 cm(2). Complete primary fascial closure anterior to the mesh was achieved in 66% of the patients. No mortalities occurred and at short term follow-up no incisional hernia recurrences have developed. Early post operative complications included a superficial skin infection not involving mesh and a recurrent enterocutaneous fistula. CONCLUSIONS The authors conclude that Rives-Stoppa repair augmented by laparoscopic components separation is an innovative method for reconstruction of complex abdominal wall defects. Laparoscopic components separation allows fascial closure to be achieved anterior to the mesh in large incisional hernias, which may reduce wound infection rates.
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Tao H, Liu W, Simmons BN, Harris HK, Cox TC, Massiah MA. Purifying natively folded proteins from inclusion bodies using sarkosyl, Triton X-100, and CHAPS. Biotechniques 2010; 48:61-4. [PMID: 20078429 DOI: 10.2144/000113304] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
We describe a rapid, simple, and efficient method for recovering glutathione S-transferase (GST)- and His6-tagged maltose binding protein (MBP) fusion proteins from inclusion bodies. Incubation of inclusion bodies with 10% sarkosyl effectively solubilized >95% of proteins, while high-yield recovery of sarkosyl-solubilized fusion proteins was obtained with a specific ratio of Triton X-100 and CHAPS. We demonstrate for the first time that this combination of three detergents significantly improves binding efficiency of GST and GST fusion proteins to gluthathione (GSH) Sepharose.
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Kaminen-Ahola N, Ahola A, Maga M, Mallitt KA, Fahey P, Cox TC, Whitelaw E, Chong S. Maternal ethanol consumption alters the epigenotype and the phenotype of offspring in a mouse model. PLoS Genet 2010; 6:e1000811. [PMID: 20084100 PMCID: PMC2797299 DOI: 10.1371/journal.pgen.1000811] [Citation(s) in RCA: 236] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 12/10/2009] [Indexed: 11/19/2022] Open
Abstract
Recent studies have shown that exposure to some nutritional supplements and chemicals in utero can affect the epigenome of the developing mouse embryo, resulting in adult disease. Our hypothesis is that epigenetics is also involved in the gestational programming of adult phenotype by alcohol. We have developed a model of gestational ethanol exposure in the mouse based on maternal ad libitum ingestion of 10% (v/v) ethanol between gestational days 0.5-8.5 and observed changes in the expression of an epigenetically-sensitive allele, Agouti viable yellow (A(vy)), in the offspring. We found that exposure to ethanol increases the probability of transcriptional silencing at this locus, resulting in more mice with an agouti-colored coat. As expected, transcriptional silencing correlated with hypermethylation at A(vy). This demonstrates, for the first time, that ethanol can affect adult phenotype by altering the epigenotype of the early embryo. Interestingly, we also detected postnatal growth restriction and craniofacial dysmorphology reminiscent of fetal alcohol syndrome, in congenic a/a siblings of the A(vy) mice. These findings suggest that moderate ethanol exposure in utero is capable of inducing changes in the expression of genes other than A(vy), a conclusion supported by our genome-wide analysis of gene expression in these mice. In addition, offspring of female mice given free access to 10% (v/v) ethanol for four days per week for ten weeks prior to conception also showed increased transcriptional silencing of the A(vy) allele. Our work raises the possibility of a role for epigenetics in the etiology of fetal alcohol spectrum disorders, and it provides a mouse model that will be a useful resource in the continued efforts to understand the consequences of gestational alcohol exposure at the molecular level.
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Coller JK, Beardsley J, Bignold J, Li Y, Merg F, Sullivan T, Cox TC, Somogyi AA. Lack of association between the A118G polymorphism of the mu opioid receptor gene (OPRM1) and opioid dependence: A meta-analysis. Pharmgenomics Pers Med 2009; 2:9-19. [PMID: 23226031 PMCID: PMC3513197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Mu opioid receptor (OPRM1) gene variants, particularly the common A118G single nucleotide polymorphism (SNP), are among the most frequently studied candidate genes associated with opioid dependence. However, despite numerous case-control studies and meta-analyses, no definitive conclusion has been reached regarding the association of the A118G SNP and risk of developing opioid dependence. This study aimed to resolve this discrepancy by reinvestigating the association between A118G SNP allelic, and for the first time, genotype frequencies and opioid dependence. A meta-analysis of sixteen case-control studies of opioid dependence was performed with a total of 5169 subjects. No association between the A118G allele (P = 0.23) and genotype (P = 0.34) frequencies and opioid dependence was found. However, significant heterogeneity between studies precluded highly definitive conclusions. In addition, the possibility that other OPRM1 SNPs albeit rarer may influence the risk of opioid dependence remains to be investigated at this level. Nonetheless, despite no evidence of a direct association with risk of dependence, A118G may still influence the pharmacological response to opioids impacting on an individual's dosage requirements.
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Ashe A, Morgan DK, Whitelaw NC, Bruxner TJ, Vickaryous NK, Cox LL, Butterfield NC, Wicking C, Blewitt ME, Wilkins SJ, Anderson GJ, Cox TC, Whitelaw E. A genome-wide screen for modifiers of transgene variegation identifies genes with critical roles in development. Genome Biol 2008; 9:R182. [PMID: 19099580 PMCID: PMC2646286 DOI: 10.1186/gb-2008-9-12-r182] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2008] [Revised: 10/22/2008] [Accepted: 12/19/2008] [Indexed: 12/22/2022] Open
Abstract
An extended ENU screen for modifiers of transgene variegation identified four new modifiers, MommeD7-D10. Background Some years ago we established an N-ethyl-N-nitrosourea screen for modifiers of transgene variegation in the mouse and a preliminary description of the first six mutant lines, named MommeD1-D6, has been published. We have reported the underlying genes in three cases: MommeD1 is a mutation in SMC hinge domain containing 1 (Smchd1), a novel modifier of epigenetic gene silencing; MommeD2 is a mutation in DNA methyltransferase 1 (Dnmt1); and MommeD4 is a mutation in Smarca 5 (Snf2h), a known chromatin remodeler. The identification of Dnmt1 and Smarca5 attest to the effectiveness of the screen design. Results We have now extended the screen and have identified four new modifiers, MommeD7-D10. Here we show that all ten MommeDs link to unique sites in the genome, that homozygosity for the mutations is associated with severe developmental abnormalities and that heterozygosity results in phenotypic abnormalities and reduced reproductive fitness in some cases. In addition, we have now identified the underlying genes for MommeD5 and MommeD10. MommeD5 is a mutation in Hdac1, which encodes histone deacetylase 1, and MommeD10 is a mutation in Baz1b (also known as Williams syndrome transcription factor), which encodes a transcription factor containing a PHD-type zinc finger and a bromodomain. We show that reduction in the level of Baz1b in the mouse results in craniofacial features reminiscent of Williams syndrome. Conclusions These results demonstrate the importance of dosage-dependent epigenetic reprogramming in the development of the embryo and the power of the screen to provide mouse models to study this process.
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Drenckhahn JD, Schwarz QP, Gray S, Laskowski A, Kiriazis H, Ming Z, Harvey RP, Du XJ, Thorburn DR, Cox TC. Compensatory growth of healthy cardiac cells in the presence of diseased cells restores tissue homeostasis during heart development. Dev Cell 2008; 15:521-33. [PMID: 18854137 DOI: 10.1016/j.devcel.2008.09.005] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2007] [Revised: 08/18/2008] [Accepted: 09/17/2008] [Indexed: 11/18/2022]
Abstract
Energy generation by mitochondrial respiration is an absolute requirement for cardiac function. Here, we used a heart-specific conditional knockout approach to inactivate the X-linked gene encoding Holocytochrome c synthase (Hccs), an enzyme responsible for activation of respiratory cytochromes c and c1. Heterozygous knockout female mice were thus mosaic for Hccs function due to random X chromosome inactivation. In contrast to midgestational lethality of Hccs knockout males, heterozygous females appeared normal after birth. Analyses of heterozygous embryos revealed the expected 50:50 ratio of Hccs deficient to normal cardiac cells at midgestation; however, diseased tissue contributed progressively less over time and by birth represented only 10% of cardiac tissue volume. This change is accounted for by increased proliferation of remaining healthy cardiac cells resulting in a fully functional heart. These data reveal an impressive regenerative capacity of the fetal heart that can compensate for an effective loss of 50% of cardiac tissue.
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Tao H, Simmons BN, Singireddy S, Jakkidi M, Short KM, Cox TC, Massiah MA. Structure of the MID1 tandem B-boxes reveals an interaction reminiscent of intermolecular ring heterodimers. Biochemistry 2008; 47:2450-7. [PMID: 18220417 DOI: 10.1021/bi7018496] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The tripartite motif (TRIM) protein family, defined by N-terminal RING, B-box, and coiled-coil (RBCC) domains, consists of either a single type 2 B-box domain or tandem B-box domains of type 1 and type 2 (B1B2). Here, we report the first structure of the B-box domains in their native tandem orientation. The B-boxes are from Midline-1, a putative ubiquitin E3 ligase that is required for the proteosomal degradation of the catalytic subunit of protein phosphatase 2A (PP2Ac). This function of MID1 is facilitated by the direct binding of Alpha4, a regulatory subunit of PP2Ac, to B-box1, while B-box2 appears to influence this interaction. Both B-box1 and B-box2 bind two zinc atoms in a cross-brace motif and adopt a similar betabetaalpha structure reminiscent of the RING, PHD, ZZ, and U-box domains, although they differ from each other and with RING domains in the spacing of their zinc-binding residues. The two B-box domains pack against each other with the interface formed by residues located on the structured loop consisting of the two antiparallel beta-strands. The surface area of the interface is 188 A2 (17% of the total surface). Consistent with the globular structure, the Tm of the tandem B-box domain (59 degrees C) is higher than the individual domains, supporting a stable interaction between the B-box 1 and 2 domains. Notably, the interaction is reminiscent of the interaction of recently determined RING dimers, suggesting the possibility of an evolutionarily conserved role for B-box2 domains in regulating functional RING-type folds.
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Massiah MA, Matts JAB, Short KM, Simmons BN, Singireddy S, Yi Z, Cox TC. Solution structure of the MID1 B-box2 CHC(D/C)C(2)H(2) zinc-binding domain: insights into an evolutionarily conserved RING fold. J Mol Biol 2007; 369:1-10. [PMID: 17428496 DOI: 10.1016/j.jmb.2007.03.017] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2007] [Revised: 02/28/2007] [Accepted: 03/05/2007] [Indexed: 11/23/2022]
Abstract
The B-box type 2 domain is a prominent feature of a large and growing family of RING, B-box, coiled-coil (RBCC) domain-containing proteins and is also present in more than 1500 additional proteins. Most proteins usually contain a single B-box2 domain, although some proteins contain tandem domains consisting of both type 1 and type 2 B-boxes, which actually share little sequence similarity. Recently, we determined the solution structure of B-box1 from MID1, a putative E3 ubiquitin ligase that is mutated in X-linked Opitz G/BBB syndrome, and showed that it adopted a betabetaalpha RING-like fold. Here, we report the tertiary structure of the B-box2 (CHC(D/C)C(2)H(2)) domain from MID1 using multidimensional NMR spectroscopy. This MID1 B-box2 domain consists of a short alpha-helix and a structured loop with two short anti-parallel beta-strands and adopts a tertiary structure similar to the B-box1 and RING structures, even though there is minimal primary sequence similarity between these domains. By mutagenesis, ESI-FTICR and ICP mass spectrometry, we show that the B-box2 domain coordinates two zinc atoms with a 'cross-brace' pattern: one by Cys175, His178, Cys195 and Cys198 and the other by Cys187, Asp190, His204, and His207. Interestingly, this is the first case that an aspartic acid is involved in zinc atom coordination in a zinc-finger domain, although aspartic acid has been shown to coordinate non-catalytic zinc in matrix metalloproteinases. In addition, the finding of a Cys195Phe substitution identified in a patient with X-linked Opitz GBBB syndrome supports the importance of proper zinc coordination for the function of the MID1 B-box2 domain. Notably, however, our structure differs from the only other published B-box2 structure, that from XNF7, which was shown to coordinate one zinc atom. Finally, the similarity in tertiary structures of the B-box2, B-box1 and RING domains suggests these domains have evolved from a common ancestor.
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Anderson PJ, Cox TC, Roscioli T, Elakis G, Smithers L, David DJ, Powell B. Somatic FGFR and TWIST Mutations are not a Common Cause of Isolated Nonsyndromic Single Suture Craniosynostosis. J Craniofac Surg 2007; 18:312-4. [PMID: 17414280 DOI: 10.1097/scs.0b013e31802d6e76] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Pathogenic mutations in FGFR2 and TWIST genes are detected in the majority of individuals with Crouzon, Pfeiffer, Apert, and Saethre-Chotzen syndromes. In contrast, mutations have been identified rarely in cases of nonsyndromic, single suture craniosynostosis. Recently, two studies confirming somatic mosaicism with local expression of an FGFR mutation have been reported. This study investigates whether somatic mosaicism could account for nonsyndromic, single suture craniosynostosis. Eight individuals with single suture craniosynostosis who were negative for known mutations in FGFR1-3 and TWIST after screening in their leucocyte DNA were tested for the presence of pathogenic mutations in suture cell-derived DNA. Five had sagittal synostosis, two had metopic synostosis, and the other unicoronal synostosis. Osteoprogenitor cells from surgically excised fusing sutures and an adjacent open suture were cultured. DNA from the cultured cells grown to passage 3 was then examined for underlying FGFR and TWIST mutations. No mutations within the exons of the FGFR or TWIST genes studied were identified in any suture cells. This study found no evidence to support the notion that mosaicism for FGFR or TWIST mutations, normally associated with syndromal forms of craniosynostosis, occur in single suture craniosynostosis. Thus, any underlying genetic defects must occur in regions outside those normally implicated in syndromal craniosynostosis, or this disorder could arise as a consequence of some other epigenetic modification.
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McGillivray G, Savarirayan R, Cox TC, Stojkoski C, McNeil R, Bankier A, Bateman JF, Roscioli T, Gardner RJM, Lamandé SR. Familial scaphocephaly syndrome caused by a novel mutation in the FGFR2 tyrosine kinase domain. J Med Genet 2006; 42:656-62. [PMID: 16061565 PMCID: PMC1736114 DOI: 10.1136/jmg.2004.027888] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Massiah MA, Simmons BN, Short KM, Cox TC. Solution structure of the RBCC/TRIM B-box1 domain of human MID1: B-box with a RING. J Mol Biol 2006; 358:532-45. [PMID: 16529770 DOI: 10.1016/j.jmb.2006.02.009] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 01/30/2006] [Accepted: 02/01/2006] [Indexed: 10/25/2022]
Abstract
B-box domains are a defining feature of the tripartite RBCC (RING, B-box, coiled-coil) or TRIM proteins, many of which are E3 ubiquitin ligases. However, little is known about the biological function of B-boxes. In some RBCC/TRIM proteins there is only a single B-box (type 2) domain, while others have both type 1 and type 2 B-box domains in tandem adjacent to their RING domain. These two types of B-boxes share little sequence similarity, except the presence of cysteine and histidine residues: eight in most B-box1 domains and seven in B-box2 domains. We report here the high-resolution solution structure of the first B-box1 domain (from the human RBCC protein, MID1) based on 670 nuclear Overhauser effect (NOE)-derived distance restraints, 12 hydrogen bonds, and 44 dihedral angles. The domain consists of a three-turn alpha-helix, two short beta-strands, and three beta-turns, encompassing Val117 to Pro164, which binds two zinc atoms. One zinc atom is coordinated by cysteine residues 119, 122, 142, 145, while cysteine 134, 137 and histidine 150, 159 coordinate the other. This topology is markedly different from the only other B-box structure reported; that of a type 2 B-box from Xenopus XNF7, which binds a single zinc atom. Of note, the B-box1 structure closely resembles the folds of the RING, ZZ and U-box domains of E3 and E4 ubiquitin enzymes, raising the possibility that the B-box1 domain either has E3 activity itself or enhances the activity of RING type E3 ligases (i.e. confers E4 enzyme activity). The structure of the MID1 B-box1 also reveals two potential protein interaction surfaces. One of these is likely to provide the binding interface for Alpha 4 that is required for the localized turnover of the catalytic subunit of PP2A, the major Ser/Thr phosphatase.
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Danchaivijitr N, Cox TC, Saunders DE, Ganesan V. Evolution of cerebral arteriopathies in childhood arterial ischemic stroke. Ann Neurol 2006; 59:620-6. [PMID: 16450385 DOI: 10.1002/ana.20800] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To investigate evolution of cerebral arteriopathy in children with arterial ischemic stroke (AIS) and its influence on recurrence. METHODS Arteriopathy severity was graded on serial magnetic resonance angiograms from 50 children with first AIS; diagnostic categories were assigned. RESULTS Arteriopathy affected 72 arteries in 43 of 50 children. Five had clinical recurrence, with reinfarction in four; another had clinically silent reinfarction. Twelve children (24%; 4 with recurrence) had progressive arteriopathy. Arteriopathy improved in 24 patients (including 1 with recurrent transient ischemic attacks) and was stable in 7 patients. Magnetic resonance angiograms remained normal in seven patients; one had recurrent stroke. Diagnoses were transient cerebral arteriopathy (n = 24), chronic cerebral arteriopathy (n = 11), arterial dissection (n = 3), possible moyamoya (n = 2), primary moyamoya (n = 1), dysplastic arteriopathy (n = 1), and cerebral vasculitis (n = 1). Some of the first two categories could represent thromboembolic arterial occlusion with recanalization. The hazard of recurrence was three times higher when arterial disease had progressed (Cox regression hazard ratio, 3.2; 95% confidence intervals, 0.5-20.3; p = 0.22). After adjustment for age and number of AIS risk factors, the hazard ratio was 3.1 (95% confidence interval, 0.4-22.2; p = 0.27). INTERPRETATION Arteriopathy frequently progresses after childhood AIS. Further studies are needed to examine the relationship between progressive arteriopathy and recurrence.
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