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[Expansion and thickness of the visual cortex of microphthalmic mice and healthy Wistar animals].

In connection with our studies about the development and the structure of the visual system of the brain of normal and genetically microphthalmic mice in this paper we have investigated the extend of the visual cortex and the thickness of the primary visual cortex (area Oc1). The most important results are: The size of the surface of the neocortex and of the areas Oc1 and Oc2m shows no significant differences between the normal and the microphthalmic mice. The whole thickness of area Oc1 is at day 20 in the microphthalmic mice significantly greater than in normal animals. In the microphthalmic mice lamina I, III and V are thicker than in normal mice. Lamina IV is in microphthalmic mice significantly thinner than in normal animals. The interpretation of these results is difficult because at PD 20 the cortex and his laminae are not full developed. But there are in the microphthalmic mice not such clear changes (reduction) on the cortical level as in the subcortical structures of the visual system. The reduction of the thickness of lamina IV maybe caused by a reduced projection from the lateral geniculate nucleus.

Animals↗

The Hallermann-Streiff syndrome.

The Hallermann-Streiff syndrome is characterised by systemic and ocular anomalies, including congenital cataract and microphthalmia. A case is presented and the differential diagnosis discussed.

Cataract↗

[Clinical and morphological studies in a case of congenital glaucoma combined with an ocular-dental-digital dysplasia (author's transl)].

Clinical and morphological studies were undertaken to characterize a case of congenital glaucoma combined with an ocular-dental-digital dysplasia in a two year old patient. Light and electromicroscopic investigations of a surgically removed trabecular specimen were carried out. A trabeculotomy had been performed at this exact site 10 months prior to removal. The existence of a canal of Schlemm was demonstrated. The regular trabecular meshwork and trabecular region was replaced by fairly dense scar tissue, containing rudimentary intertrabecular spaces. Proliferating corneal endothelial cells covered the wound area up to the uveal part of the trabecular region. The morphological findings correlated well with the clinical observation of continued raised intraocular pressure despite trabeculotomy. It is concluded that, contrary to the situation in adult onset glaucoma, the strong proliferative tendency of juvenile tissue has a marked influence on the postoperative efficacy of the trabeculotomy.

Child, Preschool↗

The prenatal development of the optic fissure in colobomatous microphthalmia.

The coloboma in the cinnamon mouse homozygous for the microphthalmia gene is caused when optic fissure closure, which normally occurs between the 11th and the 13th gestational day, does not occur. This study sought to determine the cause of this fusion failure, and to identify any foci of fusion that occur later in gestation. Microphthalmic fetuses from the 11th-20th gestational day were obtained by datemating cinnamon mice heterozygous for the microphthalmia gene. Coronal serial sections of the eyes were examined at light and electron microscopy. Initially, the fissure margins became apposed only in the posterior aspects of the eye. A failure of basement membrane disintegration at the fissure margins prevented fusion at the 12th and 13th days. On the 14th day, small foci of basement membrane disintegration were identified in the area of the developing optic disc. Although the fusion zone enlarged later in gestation, it was limited to the area of the optic disc and showed that the two retinal layers did not separate. This study has shown that abnormal growth and invagination lead to delayed apposition of the optic fissure margins. These features together with a failure of basement membrane disintegration appear to be the main factors involved in coloboma formation. It is suggested that the excessive number of outer-layer cells that are inverted into the fissure, as well as abnormal or reduced numbers of phagocytic cells, may affect the persistence of the basement membrane. Alternatively, a primary defect of the pigment epithelial cell may lead to the development of the hypercellular and nonpigmented outer layer associated with the lack of basement membrane disintegration and nonfusion in this mutant.

Animals↗

Analysis of eye lens-specific genes in congenital hereditary cataracts and microphthalmia of the miniature schnauzer dog.

The congenital hereditary cataracts and microphthalmia in the miniature schnauzer dog are inherited by an autosomal recessive mode. To understand the genetic basis of these diseases, the authors purified and analyzed leukocyte deoxyribonucleic acid (DNA) from affected and normal animals using a candidate gene approach. Because the genes that encode the lens-specific proteins, specifically, alpha, beta, and gamma crystallins and the membrane protein (MP26), are known to maintain the structure and function of the lens, the authors used complimentary DNA (cDNA) fragments that corresponded to the above genes to search for the mutations at their loci in the affected animals. They found no evidence of the gene deletion and rearrangement in any of the five loci. In addition, the hybridizable sequences of the dog DNA to the specific probes for the human chromosome 4 and 18 loci, which are reported to be involved in the abnormality of the human eye, seem to be unaffected. These data support the notion that the hereditary cataracts and microphthalmia in the dog may be associated with genes other than those reported for several animal systems.

Animals↗

Unexpected disseminated herpes simplex infection in a newborn.

Disseminated herpes simplex virus type 2 was unexpectedly discovered in a baby delivered by primary cesarean section at 36 weeks' gestation prior to rupture of the membranes. The mother was free of orogenital lesions at each prenatal examination. Examination of the placenta revealed chorioamnionitis implicating an ascending infection from the mother's infected genital tract.

Adult↗

Spontaneous, asymmetrical microphthalmia in C57B1/6J mice.

An investigation was undertaken to evaluate ocular size and shape by objective and subjective criteria to establish the incidence and laterality of spontaneous microphthalmia in the C57B1/6J mouse strain. The purpose was to provide useful information of normal and abnormal ocular development in a laboratory strain frequently used for teratogenic studies. Ten-week-old C57B1/6J mice were time mated and sacrificed at gestational day 14. Eye normality was evaluated subjectively using veterinary ophthalmology methods, and objectively by a computer derived method. A distinct laterality was noted in the right eye when compared to the left eye. Degree of laterality varied with assessment methodology (19.0% vs. 6.9% and 8.9% vs. 4.0% for the subjective and objective methods respectively). Mean eye area and histogram distributions for the right eye were consistently smaller than the left eye for all anatomical rating groups, thereby suggesting that asymmetry found in the C57B1/6J may be due to an inherent discrepancy in eye size in the strain. The data from this study suggest that when C57B1/6J mouse eyes are used as end points for teratological testing each eye should be treated as an independent unit of measure.

Animals↗

Development of visual callosal projection in the microphthalmic stain of mice 944.

The strain of mice 944 produces a recessive microphthalmy. The microphthalmic mice were compared with phenotypically healthy animals of the same litter and with 944-mice bilaterally enucleated at 1. postnatal day (pd). Comparison was done at the 5., 10., 15. and 20. pd after lesion of the right visual cortex 24 hours before. Therefore Nissl- and Fink-Heimer-series were prepared. The results are the following: At 20. pd microphthalmic mice show both retrograde and anterograde degeneration after lesion. Enucleated and control mice produce destroyed fibres only. This evidence of callosal projection in visual cortex is possible exclusive at pd 20 with satisfying results. The neurons of laminae II and III project in the animals with a normal visus exactly to the contralateral 17/18a borderline. Enucleated mice show in area 18a two or three stripes more reaching laterally. Microphthalmic mice have terminals in both area 17 and 18a.

Animals↗

[Prenatal diagnosis of various hereditary blinding diseases].

The availability of more and more reliable obstetrical echographies makes now possible to screen fetuses for microphtalmies and anophtalmies. More over, by mean of linkage studies with DNA markers within a family, we can identify the women who will transmit X-linked diseases, and realize a prenatal diagnosis. This technology can be applied to the following ophthalmological diseases: the X-linked retinoschisis, the choroideremia, the ocular albinism, the Noorie disease, and recently the retinoblastoma. From now on, the use of such a technology which makes it possible to detect ophthalmological diseases in the fetuses, is posing ethical problems especially in case of diseases without any survival prognosis involvement.

Anophthalmos↗

[Ophthalmologic manifestations of the Pierre Robin syndrome. Report of a case of microphthalmia].

The classical description of the Pierre Robin syndrome includes micrognathia, glossoptosis, airway obstruction, and usual presence of a cleft palate. The Pierre Robin syndrome is currently defined as the combination of retrognathia, cleft palate, and respiratory distress. This last is mixed, with a peripheral component due to glossoptosis and a central component due to brain stem immaturity. The main ocular manifestations found in the Pierre Robin syndrome are congenital glaucoma and severe congenital mypopia responsible for retinal detachment. Microphthalmia is infrequent. We report the case of a neonate with severe Pierre Robin syndrome and major microphthalmia documented by CT scan.

Female↗

[The microphthalmic 944 strain of mice as a model for ontogenesis studies of the visual system. Volumetric and Golgi studies on the lateral geniculate body in the pars dorsalis].

We investigated a strain of mice with recessive microphthalmy. The mutant mice were compared with phänotypically healthy animals of the same litter using following parameters: daily pattern of motor activity, EEG pattern of the visual cortex, relative brain weight, volume of the Corpus geniculatum laterale pars dorsalis (CGLd), packing density and total number of cells in the CGLd, size of neurons (perikarya, size of dendritic domains DF), structure of dendrites (number of dendrites, branching points VZP, distribution of dendritic density in relation to the perikaryon Is). Neuromorphological parameters were investigated at postnatal days (pd) 5, 10, 15 and 20. At pd 5 we did not find differences between mutant and phänotypically healthy animals. At pd 20 the CGLd's volume of the microphthalmic mice decreased by 30% and the packing density of neurons increased by 20% compared with the healthy animals of the same litter. We observed striking changes in VZP, Is and DF of the dendritic tree. The most stable parameter is the number of the primary dendrites which is between 4 and 5.

Age Factors↗

The effect of the gene for microphthalmia (mi) on the dorsal lateral geniculate nucleus of the cinnamon mouse.

The dystrophic retina of the cinnamon mouse homozygous for the gene for microphthalmia (mi/mi) has a population of large ganglion cells. Unilateral enucleation and examination of the dorsal lateral geniculate nucleus using the Fink-Heimer technique showed that, while there was continuing degeneration argyrophilia in the dorsal lateral geniculate nucleus secondary to the retinopathy, there was additional degeneration attributable to enucleation. In addition, the pattern of degeneration indicated that the axon terminals were less mature than those of the cinnamon and heterozygous (mi/+) mice. Quantitative study of the dorsal lateral geniculate nucleus in the homozygous (mi/mi) mouse showed that the nucleus is small with fewer neurons and that the markers for protein metabolism, namely volume of nucleoli and cytoplasmic RNA, are reduced when compared to the cinnamon and heterozygous (mi/+) mice. It is concluded that the portion of the retino-geniculate pathway represented by the large ganglion cells in the retina, develops in the absence of patterned visual stimuli, but is less mature and has a more limited functional activity than controls.

Aging↗

[Unilateral congenital glaucoma].

The paper reports on the case of a 6-year-old child with OD congenital glaucoma and increase of the ocular globe volume with ruptures of Descemet's membrane. VARE = 1/8 non correcting, VALE = 34 mmHg, RE--divergent strabismus. The left microphthalmus with the corneal diameter of 9 mm. Normal karyotype. Trabeculectomy was performed at the right eye. Good postsurgical evolution. This is a case of phenocopy because in the development and formation of the iridocorneal angle in the sixth month of pregnancy, a series of extrinsic teratogenous factors appeared: measles, influenza, toxemia of pregnancy that produced modifications of the trabecula.

Child↗

[Immunohistochemical study of fibronectin localization during the formation of the vascular coat under the influence of the pigment epithelium in chick embryos].

The role of fibronectin (FN) in cell interactions of retinal pigment epithelium (RPE) and mesenchyme surrounding the optic cup during choroid formation in chick embryos was studied by indirect immunofluorescence using antibodies against FN. Experimental coloboma of retina and choroid was used as a model. During the initial stages of coloboma the regions structured like retina rudiment appear in the outer layer of the optic cup. Such regions were formed in microphthalmic eyes obtained by excision of lens from the eyes of 3.5 day old chick embryos (stage 21). At stage 21 bright FN-specific immunofluorescence was observed in basal membrane located along the external surface of the normally differentiated RPE. Later on, FN-specific immunofluorescence appeared in mesenchyme condensing along the RPE. The most intensive FN-specific immunofluorescence was observed in chorio-capillary layer of choroid after 5-7 days of incubation. In microphthalmic eyes retina-like regions of RPE and adjacent mesenchyme showed negative reaction, and the choroid was not formed from the adjacent mesenchyme in such zones. The data obtained suggest that the presence of normally differentiated RPE producing FN-containing basal membrane is necessary for the formation of chorio-capillary layer of the choroid in chick embryos.

Animals↗