Electronegative electroretinogram in mucolipidosis IV
ABSTRACT To demonstrate the progression of electroretinographic (ERG) findings in mucolipidosis IV.
Two patients with mucolipidosis IV were examined clinically and their condition was followed up for ophthalmic manifestations of the disease. Electroretinograms were performed on both patients, and conjunctival biopsy specimens were analyzed for characteristic ultrastructural inclusion bodies using light and electron microscopy. Genomic DNA isolated from peripheral blood was screened for 2 major founder mutations in the ML4 gene using polymerase chain reaction and restriction fragment length polymorphism analyses. Haplotypes were confirmed by automated sequencing of polymerase chain reaction products.
In patient 1, an ERG obtained at 12 months of age showed mildly subnormal amplitude of rod-mediated and cone-mediated responses and significantly prolonged rod and cone b-wave implicit times. An ERG obtained when the patient was 6.6 years old disclosed marked progression with greater loss of b-wave than a-wave responses to rod-and-cone-mediated activity. Scotopic ERG at the highest intensity was electronegative in configuration. In patient 2, ERG showed minimal rod-mediated responses, severely subnormal cone-mediated responses, and prolonged cone b-wave implicit times. Again, electronegative configuration of the scotopic bright flash response indicated greater disturbance of b-wave generators.
Novel ERG findings in 2 cases of mucolipidosis IV are reported with associated clinical courses, histopathologic abnormality, and genetic studies. In both cases ERGs demonstrate an electronegative configuration, suggesting that the primary retinal disturbance in mucolipidosis IV may occur at or proximal to the photoreceptor terminals.
- Endeavour 01/1983; 7(1). DOI:10.1016/0160-9327(83)90044-3 · 0.26 Impact Factor
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ABSTRACT: Thermomechanical strain was directly measured using a computer image processing technique in an area encompassing the solder-copper interface near the corner of an outermost solder ball in a chip scale package (CSP). Due to the ultra-high spatial resolution of the technique, the shear strain concentration was revealed and quantified over the area with linear dimensions in terms of microns. Discussions are given on the significance of the measurement for identifying the root cause for solder joint failure, and on the application prospects for the technique as an experimental tool in emerging areas of research where microscopic strain measurement is neededThermal and Thermomechanical Phenomena in Electronic Systems, 1998. ITHERM '98. The Sixth Intersociety Conference on; 06/1998
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ABSTRACT: The configuration and progression of the ERG in two children with mucopolysaccharidosis (MPS) I H/S (Hurler-Scheie syndrome) and MPS I H (Hurler syndrome) is described. Physical examination, biochemical analysis, ophthalmic examination and electroretinography were performed. The Hurler-Scheie patient (case 1) showed negative scotopic but normal photopic ERGs, which remained unchanged over 2 years. The Hurler patient (case 2) showed negative scotopic and photopic ERGs which did not alter after bone marrow transplantation (BMT). One year after BMT, further b-wave amplitude reduction had caused the ERGs to become more negative. The electronegative configuration of the ERGs suggests that, in these cases of MPS, the primary retinal abnormality in MPS I may be faulty synaptic transmission from photoreceptors to more proximal elements, deficient bipolar responsivity, or Muller cell disease. Further degradation with time suggests the defect to be progressive with BMT causing little or no improvement. In the Hurler-Scheie syndrome case, the defect appears to spare the cone system and to show little or no progression.Documenta Ophthalmologica 06/2007; 114(3):153-8. DOI:10.1007/s10633-007-9047-z · 1.11 Impact Factor