13 results on '"Clark IH"'
Search Results
2. A rare and unusual congenital arteriovenous communication of the retina
- Author
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Chatterjee, S, primary, Hope-Ross, M, additional, Clark, IH, additional, and Chell, PB, additional
- Published
- 2004
- Full Text
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3. Growth of long-term survivors of liver transplantation.
- Author
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Viner RM, Forton JT, Cole TJ, Clark IH, Noble-Jamieson G, Barnes ND, Viner, R M, Forton, J T, Cole, T J, Clark, I H, Noble-Jamieson, G, and Barnes, N D
- Abstract
Objective: To assess growth in survivors of liver transplantation.Study Design: Growth was studied in 105 children up to seven years after liver transplantation.Results: At transplantation, mean height standard deviation score (zH) was -1.22 but 19% of patients were severely growth retarded (height below 0.4th centile). Growth and pubertal retardation were seen in the first six months after liver transplantation. Significant catch up in growth and puberty continued for more than five years. At five years, mean zH was -0.95 and at seven years -0.84. The mean zH of patients at final height was -0.55. zH at six months was predicted by zH and bilirubin at the time of transplantation and prednisolone dose at six months. At four years, zH was predicted by zH at the time of transplantation and the cumulative prednisolone dose. There was no association between zH and age at transplantation, sex, or diagnosis, although those with biliary atresia and those undergoing transplantation under 2 years of age showed more initial growth delay and subsequent catch up. Average age at menarche was 14.2 years.Conclusions: The mean height of the group to have reached final height after liver transplantation was on the 27th centile. Those transplanted earlier in childhood are likely to achieve more normal final heights. High steroid dose, poor liver function, and retransplantation are associated with poorer height outcomes. Persisting severe short stature is largely confined to children with severely retarded growth at the time of transplantation. Transient delay in puberty and menarche occur early after transplantation, although appropriate pubertal progress is resumed after two to three years. [ABSTRACT FROM AUTHOR]- Published
- 1999
4. Ex vivo method for rapid quantification of post traumatic brain injury lesion volumes using ultrasound.
- Author
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Clark IH, Natera D, Grande AW, and Low WC
- Subjects
- Animals, Male, Disease Models, Animal, Mice, Inbred C57BL, Mice, Image Processing, Computer-Assisted methods, Time Factors, Brain Injuries, Traumatic diagnostic imaging, Brain Injuries, Traumatic pathology, Ultrasonography methods, Brain diagnostic imaging, Brain pathology
- Abstract
Background: Studies of traumatic brain injury often involve the quantification of the lesion volume as a major outcome measure. The determination of lesion volume typically employs the cutting and mounting of brain tissue, and the calculation of the cross-sectional area of the lesion within each section of brain after histological staining. This is a time consuming and laborious task often requiring many weeks to determine the lesion volume for an individual brain., Methods: In this report we present a method for determining the lesion volume within the brain following traumatic brain injury that involves the use of ultrasound imaging. With this process the lesion volume can be determined within a time period of 90 min per brain rather than weeks and months. Moreover, we have developed a pipeline that will combine the cross-sectional ultrasound images of the brain with the Allen Mouse Brain Atlas to provide the precise anatomical structures that are affected by traumatic injury to the brain. The anatomical detail was lastly paired with behavioral data showing neurological deficits correlated with specific areas of brain injury., Results: The accuracy and precision of this method was shown to be highly consistent with the traditional histological approach. Additionally, the mapping process and behavioral data show that neurological recovery from 1 to 3 weeks post injury is not correlated with gross anatomical recovery of the TBI lesion in our TBI model., Conclusion: Together these approaches will enhance the pipeline for processing brain tissue in experimental conditions where the lesion volume is an important outcome parameter and provide more high resolution information about the identity of the damaged regions of the brain., Competing Interests: Declaration of Competing Interest None., (Copyright © 2024 Elsevier B.V. All rights reserved.)
- Published
- 2024
- Full Text
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5. Ophthalmic and Neuroimaging Associations In Optic Nerve Hypoplasia/Septo-Optic-Pituitary Dysplasia.
- Author
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Salman MS, Hossain S, Carson E, Clark IH, and Rozovsky K
- Abstract
Background: Optic nerve hypoplasia (ONH) and septo-optic-pituitary dysplasia (SOD) are neurodevelopmental disorders associated with congenital visual impairment. Our aim was to investigate associations between several ophthalmic and neuroimaging features in patients with ONH/SOD., Methods: A retrospective chart and neuroimaging review was performed in patients with ONH/SOD. Ophthalmic signs (e.g., monocular best-corrected visual acuity [BCVA], nystagmus, and strabismus) and neuroimaging data were extracted and their associations were investigated., Results: There were 128 patients (70 males) with ONH/SOD who had neuroimaging. Their mean age at the end of the study was 13.2 ( SD : 7.5) years. Ophthalmic data were available on 102 patients (58 males). BCVA varied from normal to no light perception. There were statistically significant associations between: (A) Reduced optic nerve or chiasm size on neuroimaging and more severely impaired BCVA and (B) laterality of the reduced optic nerve or chiasm size on neuroimaging and laterality of: (1) The eye with reduced BCVA, (2) small optic disc size, and (3) RAPD, if present ( p ≤ 0.0002 each). The presence of symmetrically small optic nerves on MRI was significantly more common in patients with nystagmus than when nystagmus was absent ( N = 96, 75% vs. 38.6%, p < 0.0001). The presence of neuronal migration disorders, their type and laterality were not associated with BCVA and laterality of the reduced BCVA., Conclusion: The functional and structural associations in ONH are consistent with the impaired visual function that results from the hypoplastic anterior visual pathways. However, these associations were not perfectly concordant making prediction of adult BCVA challenging in these patients.
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- 2024
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6. Visual Acuity Outcomes in Children With Optic Nerve Hypoplasia and Septo-Optic-Pituitary Dysplasia.
- Author
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Salman MS, Hossain S, Carson E, Ruth CA, and Clark IH
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- Male, Child, Humans, Reproducibility of Results, Optic Nerve diagnostic imaging, Visual Acuity, Retrospective Studies, Optic Nerve Hypoplasia, Pituitary Diseases
- Abstract
Background: To investigate best-corrected visual acuity (BCVA) outcomes in patients with optic nerve hypoplasia (ONH)/septo-optic-pituitary dysplasia (SOD). Our primary hypothesis was that BCVA in patients with ONH/SOD does not change significantly over time., Methods: A chart review was undertaken in patients with a confirmed diagnosis of ONH/SOD. Demographic and clinical ophthalmologic data were extracted. Quantitative BCVA data were investigated across clinic visits after converting acuities to the logarithm of the minimum angle of resolution (logMAR)., Results: There were 102 patients (56 males). Median age at the end of the study was 12.7 years. Median duration of follow-up was 4.5 years. BCVA significantly worsened slightly in the most affected eyes (0.056 average increase in logMAR/year, 95% confidence interval [CI]: 0.037 to 0.075) and significantly improved mildly in the lesser or equally affected eyes (0.014 average decrease in logMAR/year, 95% CI: 0.009 to 0.019) (P < 0.0001)., Conclusions: Although the overall BCVA data showed a statistically significant change with time, the actual changes were small and are of doubtful meaningful clinical significance (less than one line change on a Snellen chart). Our data suggest that ONH/SOD are nonprogressive neurodevelopmental disorders. The mild worsening of BCVA in the most affected eyes may be caused by amblyopia, whereas the small improvement in the lesser or equally affected eyes may be caused by developmental maturation. In addition, the changes in BCVA may also be due to increasing reliability of visual assessments with increasing age., Competing Interests: Declaration of competing interest There are no financial disclosures related to this work. M.S.S. has a grant from Fighting Blindness Canada to fund other research projects., (Copyright © 2023 Elsevier Inc. All rights reserved.)
- Published
- 2023
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7. Mapping brain networks in MPS I mice and their restoration following gene therapy.
- Author
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Zhu W, Ou L, Zhang L, Clark IH, Zhang Y, Zhu XH, Whitley CB, Hackett PB, Low WC, and Chen W
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- Humans, Animals, Mice, Brain diagnostic imaging, Genetic Therapy methods, Brain Mapping methods, Magnetic Resonance Imaging, Mucopolysaccharidosis I genetics, Mucopolysaccharidosis I therapy
- Abstract
Mucopolysaccharidosis type I (MPS I) is an inherited lysosomal disorder that causes syndromes characterized by physiological dysfunction in many organs and tissues. Despite the recognizable morphological and behavioral deficits associated with MPS I, neither the underlying alterations in functional neural connectivity nor its restoration following gene therapy have been shown. By employing high-resolution resting-state fMRI (rs-fMRI), we found significant reductions in functional neural connectivity in the limbic areas of the brain that play key roles in learning and memory in MPS I mice, and that adeno-associated virus (AAV)-mediated gene therapy can reestablish most brain connectivity. Using logistic regression in MPS I and treated animals, we identified functional networks with the most alterations. The rs-fMRI and statistical methods should be translatable into clinical evaluation of humans with neurological disorders., (© 2023. Springer Nature Limited.)
- Published
- 2023
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8. Cell Reprogramming for Regeneration and Repair of the Nervous System.
- Author
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Clark IH, Roman A, Fellows E, Radha S, Var SR, Roushdy Z, Borer SM, Johnson S, Chen O, Borgida JS, Steevens A, Shetty A, Strell P, Low WC, and Grande AW
- Abstract
A persistent barrier to the cure and treatment of neurological diseases is the limited ability of the central and peripheral nervous systems to undergo neuroregeneration and repair. Recent efforts have turned to regeneration of various cell types through cellular reprogramming of native cells as a promising therapy to replenish lost or diminished cell populations in various neurological diseases. This review provides an in-depth analysis of the current viral vectors, genes of interest, and target cellular populations that have been studied, as well as the challenges and future directions of these novel therapies. Furthermore, the mechanisms by which cellular reprogramming could be optimized as treatment in neurological diseases and a review of the most recent cellular reprogramming in vitro and in vivo studies will also be discussed.
- Published
- 2022
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9. Selected Ophthalmological Features in Children with Septo-Optic Dysplasia and Optic Nerve Hypoplasia.
- Author
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Salman MS, Hossain S, Carson E, Ruth CA, and Clark IH
- Abstract
Septo-optic dysplasia (SOD) and optic nerve hypoplasia (ONH) cause congenital visual impairment. Their aetiology is mostly unknown. Our aim was to investigate the prevalence of selected ophthalmological features in patients with these disorders. A chart review was performed on patients with SOD/ONH. Ophthalmological data were extracted. There were 102 patients (56 males). The median age at the end of the study was 12.7 years. Best-corrected visual acuity ranged from normal to no light perception. Bilateral ONH was more common than unilateral ONH. Strabismus (85%) and to a lesser extent nystagmus (52%) were both very common in our cohort. Patients with esotropia had worse visual acuity than those who had exotropia. The presence of nystagmus was more likely in cases with bilateral ONH. Therefore, patients with SOD/ONH may have normal visual acuity. Many have strabismus, which may cause amblyopia thereby further decreasing visual acuity. Nystagmus occurs commonly and its presence typically indicates bilateral ONH., Competing Interests: No potential conflict of interest was reported by the authors., (© 2022 Taylor & Francis Group, LLC.)
- Published
- 2022
- Full Text
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10. Longstanding and Refractory Anti-Muscle Specific Tyrosine Kinase Antibody-Associated Myasthenia Gravis (Anti-MuSK-MG) in a Child Successfully Treated with Rituximab.
- Author
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Weger S, Appendino JP, and Clark IH
- Subjects
- Child, Electromyography, Female, Humans, Myasthenia Gravis drug therapy, Remission Induction, Autoantibodies blood, Immunologic Factors therapeutic use, Myasthenia Gravis immunology, Receptor Protein-Tyrosine Kinases immunology, Receptors, Cholinergic immunology, Rituximab therapeutic use
- Abstract
Anti-muscle specific tyrosine kinase antibody-associated myasthenia gravis (MuSK-MG) is a rare subtype of MG characterized by more frequent relapses and a clinical course that is refractory to standard treatments. Rituximab, a monoclonal antibody targeting CD20+ B cells, has been used effectively in the adult population to achieve stable remission. We describe a pediatric patient with MuSK-MG who demonstrated an excellent response to rituximab after failing standard therapy.
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- 2019
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11. Eyelid Retraction in Isolated Unilateral Congenital Blepharoptosis.
- Author
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Salman MS and Clark IH
- Abstract
Isolated unilateral congenital ptosis is encountered relatively infrequently in clinical practice. It typically consists of a unilateral droopy eyelid, weak levator palpebrae superioris muscle function, lid lag, and an absent upper lid crease with no other abnormalities on examination. We present a four-and-a-half-year-old girl with isolated and mild unilateral congenital ptosis who unexpectedly demonstrated a static upper eyelid on downgaze in conjunction with a well-formed upper lid skin crease. We attribute this uncommon sign in congenital ptosis to stiffness and presumed fibrosis of the levator muscle. Examining the function of the eyelids in all directions of gaze is important in patients with abnormalities of lid position, since additional useful information can be gleaned about the status of the levator muscle including, aberrant regeneration or fibrosis.
- Published
- 2017
- Full Text
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12. Congenital Oculomotor Nerve Paresis With Isolated Cyclic Pupillary Spasms.
- Author
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Salman MS, Klassen SF, and Clark IH
- Subjects
- Female, Humans, Infant, Oculomotor Nerve physiopathology, Paresis complications, Paresis pathology, Pupil Disorders complications, Spasm complications
- Abstract
Cyclic oculomotor nerve paresis is a rare and usually congenital disorder. It is characterized by unilateral third nerve paresis with periodic spasms causing eyelid elevation, miosis, and contraction of 1 or more of the extraocular muscles innervated by the third nerve. We report a 20-month-old girl who presented initially with a congenital partial right third nerve paresis without ptosis. She subsequently developed isolated cyclic spasms of the pupil followed several months later by permanent partial ptosis.
- Published
- 2015
- Full Text
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13. Orbital trauma: which side?
- Author
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Gibbons AJ, Abdullakutty A, Clark IH, and Millar BG
- Subjects
- Adult, Humans, Male, Tomography, X-Ray Computed, Diagnostic Errors prevention & control, Orbital Fractures diagnostic imaging
- Published
- 2005
- Full Text
- View/download PDF
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