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At least 469 records · Page 26Linked to original sources

Safety of unwrapped spherical orbital implants.

PURPOSE: To determine the exposure rate of unwrapped spherical orbital implants after enucleation surgery. METHODS: Retrospective review of consecutive case series. All patients undergoing orbital implantation during enucleation surgery from October 1999 to September 2003 were included. Charts were reviewed for preoperative diagnoses, type and size of implant, use of a wrapping material, and complications. RESULTS: Twenty-six consecutive patients underwent enucleation surgery without wrapping material. Nineteen patients received porous polyethylene, 5 patients received polymethylmethacrylate, and 2 received hydroxyapatite. Mean implant diameter was 21.03 mm. Mean follow-up was 17.1 months (range, 2 to 43 months). There were no complications of implant extrusion, exposure, infection, or migration. CONCLUSIONS: The use of unwrapped spherical orbital implants may be associated with a low rate of early exposure. Careful choice of implant type may help reduce the risk of implant exposure.

Adolescent↗

Conjunctival biopsy of anophthalmic socket in sarcoidosis.

A case of sarcoidosis was diagnosed by a random conjunctival biopsy from an anophthalmic socket. A 22-year-old black female patient presented with anterior and posterior uveitis and subconjunctival nodules in the left eye. Her right eye was enucleated due to a penetrating injury 3 years before admission. Biopsy of subconjunctival nodules in the left eye failed to demonstrate granulomatous inflammation; however, a random conjunctival biopsy from the normal-appearing anophthalmic socket conjunctiva revealed noncaseating granulomas. Conjunctival biopsy is a safe, cost-effective means of diagnosis in sarcoidosis suspects. To our knowledge, this is the first reported case of sarcoidosis confirmed with random conjunctival biopsy from an anophthalmic socket.

Adult↗

Infiltrating orbital astrocytic proliferation associated with congenitally malformed eyes.

This report describes the clinical and pathologic findings in two adults with orbital infiltration by astrocytic cells associated with congenitally malformed eyes. Both cases had enlarging orbital masses and underwent complete resection. Histopathology revealed proliferation of astrocytes (fibrillary acidic protein-positive) that invaded the orbital tissues. To the best of our knowledge, there are no similar cases in the literature.

Adult↗

Expansion of the socket and orbit for congenital clinical anophthalmia.

BACKGROUND: Congenital clinical anophthalmia requires fitting an artificial eye, achieving a pleasing aspect of the palpebral apparatus, and stimulating growth of the orbit, as well as of the entire midface. METHODS: Out of 25 patients with clinical anophthalmia, 22 were treated according to a new protocol (first described by Wiese et al. in 1999) and followed for up to 6 years. In 10 patients, anophthalmia was bilateral, in nine patients, it was on the right side only and in three it was on the left side only. Treatment consisted of implantation of an osmotic expander to first stimulate growth of the conjunctival sac and eyelids followed by serial implantation of osmotic expanders to stimulate growth of the orbit (and thus of the midface). The material used was a copolymer of methylmethacrylate and N-vinylpyrrolidone. RESULTS: Fitting of an artificial eye was without any problem within the first year of life for the most part. Growth of the orbit was stimulated by more than 65 percent of a healthy one. Aesthetically, the results were very largely pleasing. Complications were encountered, especially when the wrong expander sizes had been implanted. CONCLUSION: Using osmotic expanders of this type, through a staged therapy of minor operations, promises to achieve all goals before the child enters school.

Abnormalities, Multiple↗

SOX2 is a dose-dependent regulator of retinal neural progenitor competence.

Approximately 10% of humans with anophthalmia (absent eye) or severe microphthalmia (small eye) show haploid insufficiency due to mutations in SOX2, a SOXB1-HMG box transcription factor. However, at present, the molecular or cellular mechanisms responsible for these conditions are poorly understood. Here, we directly assessed the requirement for SOX2 during eye development by generating a gene-dosage allelic series of Sox2 mutations in the mouse. The Sox2 mutant mice display a range of eye phenotypes consistent with human syndromes and the severity of these phenotypes directly relates to the levels of SOX2 expression found in progenitor cells of the neural retina. Retinal progenitor cells with conditionally ablated Sox2 lose competence to both proliferate and terminally differentiate. In contrast, in Sox2 hypomorphic/null mice, a reduction of SOX2 expression to <40% of normal causes variable microphthalmia as a result of aberrant neural progenitor differentiation. Furthermore, we provide genetic and molecular evidence that SOX2 activity, in a concentration-dependent manner, plays a key role in the regulation of the NOTCH1 signaling pathway in retinal progenitor cells. Collectively, these results show that precise regulation of SOX2 dosage is critical for temporal and spatial regulation of retinal progenitor cell differentiation and provide a cellular and molecular model for understanding how hypomorphic levels of SOX2 cause retinal defects in humans.

Alleles↗

Fraser syndrome (cryptophthalmos with syndactyly) in the fetus and newborn.

Clinical and autopsy findings in two fetuses and one newborn infant with Fraser syndrome are presented. Discussion focuses on the range of phenotypic expression within this autosomal-recessive disorder, the resulting difficulties in prenatal and postnatal diagnosis, and on the concept of a neurocristopathy as underlying disturbance.

Abnormalities, Multiple↗

Oculocerebrocutaneous syndrome: report of three additional cases and aetiological considerations.

The oculocerebrocutaneous (OCC) syndrome is characterized by the presence of orbital cysts and microphthalmia/anophthalmia, focal hypo- and aplastic skin defects, skin appendages and cerebral malformations. Most of the patients suffer from psychomotor retardation and seizures. To date, 23 patients in total have been reported. We report on three additional cases which illustrate the broad clinical spectrum of this disorder. In one case, the differentiation between OCC syndrome and encephalocraniocutaneous lipomatosis was difficult. A brief review of the clinical features of OCC syndrome is given. Possible aetiological hypotheses are discussed, namely survival of a lethal mutation by mosaicism, an autosomal dominant mutation and external causal factors. Disruption of the anterior neuroectodermal plate seems to be the most probable pathogenic mechanism.

Abnormalities, Multiple↗

The appearance of alpha, beta and gamma crystallins in an anophthalmic strain of mice.

A certain percentage of congenitally anophthalmic mouse embryos have the ability to generate small lens vesicles that have previously been shown to produce alpha crystallin at 13-day gestation. Further immunohistological analysis of 13- and 15-day-gestation anophthalmia embryos indicates that beta crystallin is present in those 13-day embryos which have lens vesicles with lens-fiber formation. Also, 15-day embryos with lenses demonstrating fiber elongation can produce both beta and gamma crystallins. The conclusion is drawn that the genetic potential to produce at least three characteristic biochemical markers of normal lens differentiation is present in the anophthalmia mutant. The spatial distribution patterns of the crystallins in normal and anophthalmia embryos were similar. However, there appeared to be a transposition in the temporal appearance of beta and gamma crystallins in the anophthalmia mutant. Optic cups and associated lenses in 15-day anophthalmia specimens were much smaller than those in controls. The optic and lens rudiments in these anophthalmia embryos were fairly proportional in size, which indicates that some degree of allometric growth compensation had occurred during the course of development. This ability for differential growth compensation in the mouse eye appears to be restricted to the predifferentiative stages of eye formation.

Animals↗

Environmental enrichment enhances auditory takeover of the occipital cortex in anophthalmic mice.

Enrichment of the environment is an effective means of enhancing neuronal development and plasticity but its effect on the cross-modal compensation resulting from sensory deprivation has never been investigated. The present study used c-Fos immunohistochemistry and dextran-biotin neuronal tracing to examine the reorganization of sensory modalities in the brain of anophthalmic mutant mice (ZRDCT/An) raised in either enriched or standard environments. Auditory stimulation was found to elicit strong neuronal activation in thalamic and cortical structures that are normally visual. An important finding was that the latter auditory-evoked cortical activity was considerably enhanced in blind mice raised in the enriched environment. The axonal tracing study demonstrated auditory inputs from the inferior colliculus to the visual thalamus. This animal model will be useful for understanding neuronal mechanisms underlying some cross-modal sensory phenomena observed in blind or deaf humans.

Acoustic Stimulation↗

Early midline interactions are important in mouse optic chiasm formation but are not critical in man: a significant distinction between man and mouse.

The optic chiasm is one of the most popular models for studying axon guidance. Here axons make a key binary decision either to cross the midline to innervate the contralateral hemisphere or to remain uncrossed. In rodents, midline interactions between axons from the two eyes are critical for normal development, as early removal of one eye systematically disrupts hemispheric projections from the remaining eye, increasing the crossed projection at the expense of the uncrossed. This is similar to the abnormal decussation pattern seen in albinos. This pattern is markedly different in marsupials where early eye removal has no impact on projections from the remaining eye. These differences are related to the location of the uncrossed projection through the chiasm. In rodents these axons approach the midline whereas in marsupials they remain segregated laterally. We provide anatomical evidence in man suggesting that, unlike in rodents, uncrossed axons are confined laterally and do not mix in each hemi-chiasm, which is a pattern similar to that found in marsupials. Further, we demonstrate electrophysiologically, using visual cortical evoked potentials, that the failure of one eye to develop in man has no impact on the hemispheric projections from the remaining eye. These data demonstrate that the mechanisms regulating chiasmal development in man differ from those in rodents but may be similar to those in marsupials. We suggest that mouse models of the organization and development of the optic chiasm are not common to placental mammals in general.

Adolescent↗

Congenital anophthalmia associated with intracranial germinoma.

A 14-year-old boy with anophthalmia presented evidence of hypothalamic dysfunction. He was found to have a third-ventricular germinoma, probably pineal. This case is interesting in view of a previous case report of the association of anophthalmia and a germ-cell tumor (teratoma), and suggests a possible causal relationship between this malformation and germ-cell neoplasms, bith of which probably arise early in development.

Adolescent↗

Three dimensional ultrasound: abnormalities of the fetal face in surface and volume rendering mode.

OBJECTIVE: To evaluate three dimensional ultrasound in surface and volume rendering mode in fetal malformations of the face. SETTING: Day assessment unit in a university hospital. SUBJECTS: Four cases have been examined: two cases represented cleft lip, one case was a male with trisomy 13 (Patau syndrome) with proboscis, and one case represented a male fetus with unilateral anophthalmia. CONCLUSION: A new technique of three dimensional ultrasound visualisation in fetal malformation using surface and volume rendering is presented. The equipment consisted of a commercially available ultrasound machine, a built-in graphic workstation, and three dimensional software. Post-processing of data required approximately 10 minutes of calculation. The application of three dimensional ultrasound in complex malformations of the face appears to provide reasonable value for prenatal diagnosis and may become clinically useful in the near future.

Adult↗

Structural analysis of the genes for human arylamine N-acetyltransferases and characterisation of alternative transcripts.

Arylamine N-acetyltransferases are polymorphic drug-metabolising enzymes. The human isoforms, NAT1 and NAT2, are encoded by two genes with intronless coding regions. Human NAT1 protein is found in many tissues, unlike NAT2 which is present predominantly in the intestine and liver. We describe the exon-intron structure of the human NAT genes by analysing data from genomic databases. Comparison of expressed sequence tags, matching NAT gene sequences, with the sequence of human chromosome 8 implied the presence of 8 non-coding exons located 51.5, 51.4, 12.3, 11.9, 10.8, 9.6, 5.2 and 2.6 kb upstream of the single coding exon of the NAT1 gene. A number of expressed sequence tags also indicated transcription initiation from the upstream region adjacent to the NAT1 coding exon, consistent with earlier studies. The NAT2 gene consists of one previously described non-coding and one coding exon, located 8.6 kb apart. These findings were also confirmed by RT-PCR, using cDNA from heart, brain, placenta, lung, liver, skeletal muscle, kidney and pancreas. Alternatively spliced NAT1 transcripts were found in all tissues. Transcription of the NAT2 gene was also detected in these tissues and was demonstrated to start either from the non-coding exon or from immediately upstream of the coding exon. Comparison of the RT-PCR products provided an initial estimate of the relative amounts of the different NAT transcripts expressed in each tissue. Finally, both expressed sequence tag analysis and RT-PCR demonstrated the presence of two differentially utilised polyadenylation signals for NAT1 and NAT2, located about 0.2 and 0.3 kb downstream of the coding region of each gene.

Alternative Splicing↗

BMP 7 is required for nephrogenesis, eye development, and skeletal patterning.

In summary, the generation of BMP-7-deficient mice has provided additional evidence that this family of growth factors regulate many morphogenetic processes including but not limited to skeletal development. In particular our experiments demonstrate that BMP 7 acts as an early inducer of glomeruli formation, and that it is required for skeletal patterning and lens formation. Our results not only demonstrate that BMP 7 is involved in the differentiation of several organs during development, but also raise the hypothesis that mutations in the Bmp 7 gene itself or in the genetic pathway could be responsible for several human genetic diseases in which glomerulus formation is impaired.

Animals↗