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PubMed1984

Transformation of white locus DNA in drosophila: dosage compensation, zeste interaction, and position effects.

P-element-mediated DNA transformation was used to generate transformants carrying segments of DNA from the white locus of D. melanogaster. The vast majority of transduced copies of an 11.7 or a 14.3 kb segment of DNA from white successfully rescued the white- eye-color phenotype when inserted in many different chromosomal locations. However, two transformants with abnormal eye pigmentation--apparently a consequence of the genomic positions of the transduced white gene--were also recovered. In all seven cases tested, autosomal insertions of white, which is dosage-compensated in its normal location on the X chromosome, retained the property of dosage compensation. In contrast to the relative insensitivity of eye-color pigmentation and dosage compensation to genomic position, the transduced white DNA segments differed widely in their interactions with the zeste mutation, ranging from greater than normal repression by zeste to insensitivity to the presence of zeste.

Animals↗
PubMedDate not supplied

Retinal toxicity of intravitreal triamcinolone acetonide: a morphological study.

PURPOSE: To evaluate the morphologic effects of intravitreal triamcinolone acetonide (TA) on rabbit retina. METHODS: Intravitreal injections of 0.5 mg, 1 mg, 4 mg, 8 mg, and 20 mg of TA (Kenalog-40; Bristol-Myers Squibb, Princeton, NJ) in 0.1 mL were given to pigmented rabbits. For control, 0.1 mL of TA vehicle and saline were injected. Animals were killed on day 14, and retinas were analyzed by light as well as electron microscopy. RESULTS: No ophthalmoscopic change was found. Eyes injected with 0.5 mg and 1 mg of TA did not have morphologic abnormality. Eyes injected with 4 mg, 8 mg, and 20 mg showed destruction of photoreceptor outer segments and migration of macrophage-like cells in the subretinal space. Eyes injected with 20 mg showed more extensive damage and increased pigment granules in the retinal pigment epithelium cells with large oil droplets in the cytoplasm. Electron microscopy also showed loss of photoreceptor/retinal pigment epithelium interdigitations. Eyes injected with vehicle or saline did not show morphologic changes. CONCLUSION: Single intravitreal injection of 0.5 mg or 1 mg of TA did not produce morphologic retinal changes in pigmented rabbits. However, injections of 4 mg, 8 mg, and 20 mg of TA produced outer retina toxic effects. These findings suggest that long-term retinal toxicity studies should be carried out, using single and repeated injections before this therapy becomes more widely used.

Animals↗
PubMed2005

Distinct developmental programs require different levels of Bmp signaling during mouse retinal development.

The Bmp family of secreted signaling molecules is implicated in multiple aspects of embryonic development. However, the cell-type-specific requirements for this signaling pathway are often obscure in the context of complex embryonic tissue interactions. To define the cell-autonomous requirements for Bmp signaling, we have used a Cre-loxP strategy to delete Bmp receptor function specifically within the developing mouse retina. Disruption of a Bmp type I receptor gene, Bmpr1a, leads to no detectable eye abnormality. Further reduction of Bmp receptor activity by removing one functional copy of another Bmp type I receptor gene, Bmpr1b, in the retina-specific Bmpr1a mutant background, results in abnormal retinal dorsoventral patterning. Double mutants completely lacking both of these genes exhibit severe eye defects characterized by reduced growth of embryonic retina and failure of retinal neurogenesis. These studies provide direct genetic evidence that Bmpr1a and Bmpr1b play redundant roles during retinal development, and that different threshold levels of Bmp signaling regulate distinct developmental programs such as patterning, growth and differentiation of the retina.

Animals↗
PubMed1988

The effect of neuroleptics and tardive dyskinesia on smooth-pursuit eye movement in chronic schizophrenics.

We sought to determine whether such state-related factors as neuroleptic treatment and facio-oral tardive dyskinesia (TD) influence smooth-pursuit eye movement (SPEM) in chronic schizophrenics. The design involved 100 schizophrenics, 64 of whom showed "abnormal" eye tracking. Experimentally drug-withdrawn patients, some of whom were clinically relapsed, were compared with control patients who continued taking medication in prewithdrawal and postwithdrawal SPEM tests. All groups showed a slight worsening in eye-tracking performance on two postwithdrawal tests, but significant group-by-test session "interactions" were not demonstrable. We also determined that patients with TD tend to substitute large, nontracking saccades for SPEM to a significantly greater extent than nondyskinetic patients. Our findings strengthen the supposition that impaired SPEM is a trait in many schizophrenics but suggest that patients with TD be excluded in future studies of SPEM addressed to trait issues.

Adult↗
PubMed2004

Joubert syndrome: review and report of seven new cases.

Joubert syndrome (JS) is an autosomal-recessive disorder, characterized by hypotonia, ataxia, global developmental delay and molar tooth sign on magnetic resonance imaging. A variety of other abnormalities have been described in children with JS, including abnormal breathing, abnormal eye movements, a characteristic facial appearance, delayed language, hypersensitivity to noise, autism, ocular and oculomotor abnormalities, meningoencephaloceles, microcephaly, low-set ears, polydactyly, retinal dysplasia, kidney abnormalities (renal cysts), soft tissue tumor of the tongue, liver disease and duodenal atresia. Even within siblings the phenotype may vary, making it difficult to establish the exact clinical diagnostic boundaries of JS. We review the clinical characteristics of seven cases that fulfill the criteria of JS.

Abnormalities, Multiple↗
PubMed1997

Fine structure of the choroidal coat of the avian eye. Lymphatic vessels.

PURPOSE: To clarify the fine structure of the avian choroid and thus help explain the mechanisms for normal and abnormal eye function and growth. METHODS: Eyes from normal chickens and from experimental chickens subjected to unilateral paracentesis were fixed either by perfusion or in situ, with or without post-fixation by microwave irradiation, and then processed for light and electron microscopic analysis. RESULTS: The avian choroid contains thin-walled lacunae, whose fine structure is identical to that of lymphatic vessels. The lacunae are much smaller toward the anterior chamber and the Schlemm's canal than posteriorly in the eye bulb. Large lacunae are situated primarily in the suprachoroidea, and their blind-ended capillary branches enter the choriocapillaris and the walls of large veins. The walls of the large veins contain villous structures that protrude into their lumina and are penetrated by thin lacunar branches and by side lines of the venous lumen. In normal chickens, the lacunae usually are devoid of blood cells. After paracentesis of the anterior eye chamber, the lacunae become filled with erythrocytes on the side that was operated on, but not on the contralateral side. CONCLUSIONS: The authors propose that the lacunae of the avian choroid represent a system of posterior short lymphatic vessels, which drain intraocular fluids directly into the eye's venous system, and that the villous structures are sites of communication between lacunae and veins. The demonstration of a choroidal lymphatic system opens new insights into the processes of fluid removal, control of intraocular pressure, and regulation of choroidal thickness in the avian eye under normal and experimental conditions.

Animals↗
PubMed1981

Hormonal and metabolic abnormalities associated with central nervous system germinoma in children and adolescents and the effect of therapy: report of 10 patients.

We describe the results of clinical and endocrinological investigations performed on 10 children and adolescents (5 males and 5 females) with a primary central nervous system germinoma. Eight of 10 patients were between 10-20 yr of age at the time of initial presentation. Polyuria (7 of 10) and a decrease in or cessation of linear growth (5 of 10) were the most common presenting symptoms, while only 2 of 10 patients complained of visual problems. Two patients presented with the syndrome of polyuria, adipsia, hypernatremia, profound muscle weakness, and hyperlipidemia. Initial physical exam revealed abnormal eye findings in 60%, short stature (greater than or equal to 2.5 SD) in 50%, and abnormal pubertal development in 30% of the patients. The neoplasm was located in the suprasellar-hypothalamic region in 8, caudate nucleus in 1, and pineal region in 1. Biopsy performed in 7 patients revealed the classic two-cell germinoma in all cases. Assessment of endocrine function before radiotherapy documented pituitary deficits in all patients studied. Antidiuretic hormone was deficient in 8 of 10 patients and was associated with hypoadipsia in 4. GH was deficient in al patients tested (7 of 7). TSH (5 of 8), ACTH (3 of 7), and gonadotropin (1 of 1) deficiencies were also common before treatment. Plasma PRL concentrations were elevated in 5 of 8 patients, all with suprasellar tumors. The hCG values were elevated only in the patient with sexual precocity (1 of 10). Endocrine evaluation during the postirradiation period revealed additional instances of GH (1), ACTH (1), and gonadotropin (5) deficiencies. All 10 patients are alive without evidence of active disease 6 months to 10 yr after radiation therapy (4500-5100 R). Evidence of hypothalamic-pituitary dysfunction is an early and almost universal feature of central nervous system germ cell tumors. The importance of careful evaluation and follow-up of children with acquired anterior or combined anterior and posterior pituitary dysfunction for a suprasellar tumor is stressed.

Adolescent↗
PubMed1985

An animal model of myopia.

Myopia develops in macaque monkeys when their lids are surgically fused at birth and kept closed for one year. This experimental refractive error has many features in common with human myopia: It is caused by progressive axial elongation of the eye, is often accompanied by fundus changes, and can only be induced before eye growth has been completed. Myopia does not develop in animals raised in the dark; thus, it is triggered by an alteration of the visual input and is presumably mediated by the nervous system. In Macaca arctoides, atropine administration prevents abnormal eye elongation, and this suggests that lid-fusion myopia is caused by excessive accommodation. In M. mulatta, atropine is ineffective; furthermore, myopia develops when lids are sutured after interruption of the optic pathways. Thus, in this species accommodation can be ruled out as a determinant of eye elongation, and other neural mechanisms may be responsible for the refractive error. Our experiments suggest that the refractive state is largely programmed on a genetic basis, but that an abnormal visual experience can disrupt the process of postnatal eye growth and induce axial myopia.

Accommodation, Ocular↗
PubMed1996

Association of abnormal smooth pursuit eye movements with the deficit syndrome in schizophrenic patients.

OBJECTIVE: The authors' goal was to test the hypothesis that abnormal smooth pursuit eye movements in schizophrenic patients are associated with the deficit syndrome. METHOD: The eye movements of 24 normal comparison subjects, 32 patients with nondeficit schizophrenia, and 11 patients with deficit schizophrenia were tested with infrared oculography using foveapetal step-ramp targets. RESULTS: The group of schizophrenic patients had normal latency to pursuit onset, abnormally decreased open-loop acceleration and abnormally decreased velocity during the periods of closed-loop acceleration and steady-state pursuit. The subgroup of schizophrenic patients with the deficit syndrome had particularly poor performance during the periods of open- and closed-loop acceleration. CONCLUSIONS: Patients with schizophrenia have abnormal smooth pursuit eye movements in response to a step-ramp stimulus, and the defects are particularly pronounced in patients with the deficit syndrome. Abnormal smooth pursuit eye movements in schizophrenia and related disorders have been consistently linked with primary and enduring negative symptoms.

Adult↗
PubMed1996

[Difficulty in eye opening following left hemispheric infarction-- causative lesion and pathophysiology of abnormalities of the eye and eyelids movements].

We reported a patient suffering from difficulty in eye opening following left hemispheric infarction. A 78-year-old left-handed woman with atrial fibrillation had an acute onset of right hemiparesis and difficulty in eye opening. On admission, mild disorientation, vertical gaze palsy, right homonymous hemianopia, anosognosia of right hemiparesis, agnosia of right side of the body and forced grasping reflex of the left hand were seen. She was aware of her difficulty in opening her eyelids. Vertical saccadic eye movements were absent to command but when her head was free to move, the vertical saccadic eye movements improved that may suggest oculomotor apraxia. Bell's phenomenon was absent, and optokinetic responses were normal. Aphasia and facial apraxia were not seen. Brain CT and MRI demonstrated infarction in the territory of the anterior divisions of the left middle cerebral artery which includes the inferior frontal gyrus, middle frontal gyrus, fronto-parietal operculum and temporal operculum. SPECT disclosed hypoperfusion area in the left frontal lobe. No lesion was seen in the midbrain and pons. On the basis of these findings, cerebral emboli of the divisions of the left middle cerebral artery were diagnosed. Until about 11th days from onset, she could not open her eyelids by our verbal commands or even voluntarily, and showed paradoxical contraction of the bilateral orbicularis oculi muscles by verbal commands to open her eyes or when her eyes were forcedly opened by hands. After the 12th days from the onset, she became to be able to open her eyes voluntarily when she was asked to count the number of fingers presented in front of her face and when her families called her, but she could not open her eyes by verbal commands, which may be characteristic of apraxia of eyelid opening. She also had bilateral blephaloptosis when she opened her eyes. Considering this case together with previous reports, embolic lesion of the left cerebral hemisphere including the frontal eye field area and its adjacent areas which may be involved in higher control of eye lid movements and supranuclear vertical gaze movements was thought to cause difficulties in eye opening and vertical gaze palsy.

Aged↗
PubMed1992

Normal eye tracking is associated with abnormal morphology of medial temporal lobe structures in schizophrenia.

Eye tracking and brain morphology assessed by magnetic resonance imaging were examined in 48 patients in their first episode of schizophrenia and in 15 normal controls. Schizophrenic patients showed higher rates of eye tracking dysfunction and more abnormal brain morphology involving the lateral ventricles, medial temporal lobe (MTL) structures and the frontal-parietal cortex than controls. Enlargement of the lateral ventricles and global rating of abnormal brain morphology were significantly more prevalent in male schizophrenics than female schizophrenics. These findings indicate that abnormalities in a variety of brain regions are present in some schizophrenics during the period shortly after the first hospitalization and could not be a function of treatment or chronic illness. We found no relation between abnormal eye tracking and any single feature of abnormal brain morphology. However, normal eye tracking was significantly associated with MTL abnormalities in schizophrenics, reflecting an inverse association between quality of eye tracking and degree of abnormality in MTL structures. These results suggest that abnormal eye tracking is not mediated by the same processes that lead to structural brain anomalies in schizophrenia.

Adolescent↗
PubMed1978

Pattern shift visual evoked responses. Two hundred patients with optic neuritis and/or multiple sclerosis.

Fifty-one patients with clinically pure optic neuritis (ON) and 149 with possible, probable, or definite multiple sclerosis (MS) were tested with pattern shift visual evoked responses (PSVER) and compared with a group of 43 normal subjects. Attention was paid to response latency, intereye latency difference, as well as differences in amplitude or duration of the major positive peak (P100). Abnormal PSVER cannot be recorded from everyone with confirmed ON. Abnormal responses were recorded from 91% of all patients (including those with MS) who had a history of ON, 57% of all MS patients, and 36% of patients without a history of ON or an abnormal eye examination. Measurements of amplitude and duration proved to be of little value in this setting. Though abnormalities of PSVER are not "specific" for ON or MS, because they also result from other disease processes, they afford more reliable, quantitative documentation of abnormal conduction in visual pathways than any other clinical test.

Adolescent↗
PubMed1991

Oculomotor function during space flight and susceptibility to space motion sickness.

Horizontal vestibulo-ocular reflex (VOR) and saccadic eye movements (SEM) were studied in 18 subjects before and during five Space Shuttle missions to evaluate the effects of weightlessness and correlations between results and susceptibility to and actual presence of space motion sickness (SMS). Active sinusoidal head oscillation was the stimulus for VOR tests with vision (VVOR), with eyes shaded (VOR-ES), and VOR suppression (VOR-S). Eye movements were recorded by electrooculography and head position by a potentiometer. No pathological nystagmus or other abnormal eye movements were seen. No significant in-flight changes were seen in the gain, phase shift or waveform of VVOR, VOR-ES, or VOR-S. Statistically significant increases in saccadic latency and decreases in saccadic velocity were seen, with no change in saccadic accuracy. Preflight differences between SMS susceptible and non-susceptible subjects were noted only in VOR-S, with less complete suppression in susceptible subjects, a finding also seen in flight. During flight, VVOR gain was significantly increased in three non-affected subjects. Saccades of SMS-affected subjects showed increased latency and velocity and decreased accuracy compared to saccades of unaffected subjects.

Adult↗
PubMed2006

Unliganded thyroid hormone receptor is essential for Xenopus laevis eye development.

Thyroid hormone receptors generally activate transcription of target genes in the presence of thyroid hormone (T(3)) and repress their transcription in its absence. Here, we investigated the role of unliganded thyroid hormone receptor (TR) during vertebrate development using an amphibian model. Previous studies led to the hypothesis that before production of endogenous T(3), the presence of unliganded receptor is essential for premetamorphic tadpole growth. To test this hypothesis, we generated a Xenopus laevis TR beta mutant construct ineffective for gene repression owing to impaired corepressor NCoR recruitment. Overexpression by germinal transgenesis of the mutant receptor leads to lethality during early development with numerous defects in cranio-facial and eye development. These effects correlate with TR expression profiles at these early stages. Molecular analysis of transgenic mutants reveals perturbed expression of genes involved in eye development. Finally, treatment with iopanoic acid or NH-3, modulators of thyroid hormone action, leads to abnormal eye development. In conclusion, the data reveal a role of unliganded TR in eye development.

Animals↗
PubMed1985

Ocular findings in a new heritable syndrome of brain, eye, and urogenital abnormalities.

We studied the clinical and histopathologic ocular findings in four related males with a newly recognized syndrome consisting of microphthalmos, microencephaly, mental retardation, agenesis of the corpus callosum, hypospadius, and cryptorchidism with X-linked recessive inheritance. The ocular abnormalities include microphthalmos, corneal pannus and hypoplasia, cataracts, uveal hypoplasia, retinal dysplasia, optic nerve hypoplasia, and congenital blepharoptosis. In case 4, a female twin who died in utero (at 15 weeks' gestation) showed none of the ocular abnormalities.

Abnormalities, Multiple↗
PubMed1999

A syndrome of immune complex glomerulonephritis and ophthalmic abnormalities.

Two sibs (one male and one female) suffering from a combination of immune complex glomerulonephritis and various ophthalmologic disorders are presented. The two cases belong to a family in which the parents are not related and seven sibs are affected, three females and a male with the combination, and three males with severe ophthalmological changes and proteinuria. Clinically, case 2 had only ophthalmological manifestations but renal biopsy findings were similar to those of case 1, which could mean that all the others with eye abnormalities also had renal disease. Although there are several reports of combinations of eye and renal disorders, the sibs reported here do not fit into any of the known syndromes.

Abnormalities, Multiple↗
PubMed1996

Transcription factor genes and the developing eye: a genetic perspective.

We review the current knowledge of transcription factors in mammallan eye development. The 14 transcription factors presently known to be required for eye formation are examined in some detail, incorporating data from both humans and rodents. Aspects of the biochemistry, expression patterns, genetics, mutant phenotypes, and biological insights acquired from the examination of loss-of-function mutations are summarized. The other 32 tissue-restricted transcription factors that are currently known to be expressed in the developing or mature mammallan eye are tabulated, together with the timing and site of their ocular expression; the requirement for most of these genes in the eye is unknown. Contributions to mammallan eye development from the study of the genetics of the Drosophila eye are discussed briefly. Identification of the entire cohort of transcription factors required for eye development is an essential first step towards understanding the mechanisms underlying eye morphogenesis and differentiation, and the molecular basis of inherited eye abnormalities in humans.

Animals↗