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PubMed1988

Congenital retinal folds in Sheffield-Wistar rats.

Retinal folds are described in male rats of a Wistar-derived strain, which occasionally shows microphthalmia and cataract. The less severe lesions mainly affect the outer retinal layers and contain microretinal detachment, cell rosettes, phagocytic cells and lipid debris. More severe folds involve all the retinal layers, exhibit subretinal haemorrhage, and photoreceptor outer segment debris throughout the lesion and on the vitreal surface. The lesions are discussed in relation to previous observations of retinal folds.

Animals↗
PubMed1989

Childhood microphthalmic neurofibromatosis.

We present an atypical case of neurofibromatosis marked by young age at onset, rapid invasiveness of the tumor, the presence of curious autonomic symptoms, cranial malformation and congenital microphthalmus, a combination that suggests a new syndrome, which might be called childhood microphthalmic neurofibromatosis.

Adolescent↗
PubMed1996

Spherophakia, nanophthalmia, hypoplastic ciliary body and glaucoma in brachydactyly-associated syndromes.

Three juvenile patients showing a systemic disorder associated with small stature, brachydactyly and glaucoma were discovered to have spherophakia and a nanophthalmic axial length of the eye between 20.29 and 21.26 mm. According to clinical and radiological criteria only one patient was classified as having Marchesani syndrome; one patient suffered from an acrofacial disorder, and the third displayed typical ocular signs of Rieger syndrome. Pupillary block mechanism had led to glaucoma in all three patients. Despite iridectomy and trabeculotomy, two of them had unregulated intraocular pressure (IOP) and showed partial angleblock by progressive anterior synechiae after surgery. Ultrasonographic biomicroscopy revealed in all cases considerable hypoplasia of the ciliary body. We conclude that the clinical combination of spherophakia and brachydactyly is not necessarily limited to Marchesani syndrome. In the wide range of brachydactyly-associated syndromes an ophthalmic examination should always be performed in order to rule out ocular complications such as spherophakia and secondary glaucoma. We could not confirm Marchesani's hypothesis of a hyperplastic ciliary body in the spherophakia-brachydactyly syndrome, considering our nanophthalmic eyes. Pressure-reducing surgery in eyes with spherophakia and nanophthalmia seems to run a high risk of inducing an extensive formation of anterior synechiae.

Abnormalities, Multiple↗
PubMed1996

Coordinate extinction of melanocyte-specific gene expression in hybrid cells.

Whole cell hybrids and microcell hybrids between mouse fibroblasts and pigmented Syrian hamster melanoma cells were analyzed for coordinate regulation of melanocyte-specific gene products. Extinction of pigmentation was observed in whole-cell hybrids and in a microcell hybrid containing a single mouse chromosome (mouse chromosome 1). Analysis of melanocyte-specific transcripts using reverse transcription, combined with the polymerase chain reaction (RT-PCR), demonstrated that tyrosinase, TRP-1, TRP-2, and microphthalmia transcripts were all absent in unpigmented whole-cell hybrids and in the monochromosomal unpigmented microcell hybrid. A pigmented subclone of this microcell hybrid, however, re-expressed the tyrosinase, TRP-1, TRP-2, and microphthalmia genes. These data suggest that all of these genes are coordinately extinguished by a single fibroblast locus. Since the only fibroblast chromosome detected in the unpigmented microcell hybrid was mouse chromosome 1, these results also suggest that the extinguisher locus affecting the expression of the tyrosinase, TRP-1, TRP-2, and microphthalmia genes in hybrid cells is located on that mouse chromosome (or on a fragment of another chromosome present in the unpigmented monochromosomal microcell hybrid but undetected in our analyses). In contrast to the results with the melanocyte-specific genes mentioned above, transcripts for the melanocortin 1 receptor gene (MC1R) were present in the monochromosomal unpigmented microcell hybrid (although absent in the whole-cell hybrids). This suggests that regulation of MC1R gene expression is distinct from regulation of the other melanocyte-specific genes.

Animals↗
PubMed1983

Direct measurements of basal bone resorption in microphthalmic mice in vivo.

Microphthalmic mice and their normal littermates were prelabeled extensively in utero with 3H-tetracycline and 3H-proline, or with 45Ca alone. The loss of 3H-tetracycline and 3H-collagen from whole femur was measured from birth to 24 days of age at weekly intervals to determine bone resorption of mineral and matrix in vivo. The ratio of blood 45Ca specific activity to that of bone (blood/bone ratio) was used to reflect the interrelationship between bone, blood, and dietary calcium, as well as bone resorption. There was little, if any, loss of 3H-tetracycline and 3H-collagen from bones of the microphthalmic mutants whereas there was a marked and continuous loss (67 and 51%, respectively) from bones of the normal littermates due to normal bone modeling. Blood/bone ratio was much lower in the mutants (42-70%) compared with the normals, suggesting that blood calcium is maintained by diet. These data provide direct evidence that basal bone resorption in growing microphthalmic mice was almost completely inhibited.

Animals↗
PubMed1975

Blindness in Mentally Retarded Children. A survey of the causes of blindness in 201 notified patients.

A preliminary survey of the causes of blindness in mentally retarded children in Denmark showed that 50% of the children had optic atrophy, 12.5% had cataract while tapeto-retinal degenerations, other malformation and retrolental fibroplasia each represents 8-9% of the causes of blindness. The survey, was done through written notification and some patients with tapeto-retinal degenerations might have been wrongly diagnosed.

Blindness↗
PubMed1978

Cyclopamine and related steroidal alkaloid teratogens: their occurrence, structural relationship, and biologic effects.

A spontaneous congenital deformity is produced in lambs whose dams consume Veratrum californicum on the 14th day of gestation. The deformity is generally expressed as cyclopia, cebocephaly, anophthalmia, or microphthalmia. This teratogenic effect is produced by certain steroidal alkaloid teratogens from the plant - most notably the compound cyclopamine. Cyclopamine is a C-nor-D-homo steroid with fused furanopiperidine rings E and F at right angles to the plane of the steroid because of spiro attachment at C-17 of the steroid. Among veratrum alkaloids, only those with an intact furan ring E were teratogenic in sheep, whereas those in which the peperidine ring is not rigidly positioned at right angles to the steroid were not. Many ruminants and laboratory animals are susceptible to the teratogen. It has wide species and tissue specificity and appears to have a direct effect on the embryo, not as a consequence of metabolic alteration of its structure nor as an indirect effect through a maternal influence. Other plant sources, notably potatoes, tomatoes, and eggplant contain related spirosolane steroidal alkaloids. Among naturally occurring spirosolanes, solasodine is teratogenic in hamsters, but neither tomatidine not diosgenin, the non-nitrogen containing analog of solasodine, is teratogenic. Results of these and other studies suggest that a basic nitrogen positioned alpha with respect to the steroidal plane and at appropriate distance beyond the D ring confers the teratogenicity on the molecule. Potato sprouts with high alkaloid content are teratogenic in hamsters, but tubers and peels are not.

Abnormalities, Drug-Induced↗
PubMed1976

Osteopetrosis of microphthalmic mice -- a defect of the hematopoietic stem cell.?

The recessive genes mi and gl in the homozygous state determine, among other phenotypic effects, osteopetrosis in the house mouse. From a stock carrying mi derived from Grüneberg (1963) the mi gene was bred into the standard CBA/H inbred strain. Microphthalmic mice of these two stocks and their hybrids were treated as newborn by intraperitoneal injection and at weaning or maturity by intravenous injection of cell suspensions containing hematopoietic stem cells from phenotypically normal mice. Resolution of much of the osteopetrosis but not the other phenotypic effects occurred within a few months in the majority of cases, provided syngeneic or H-2 compatible allogeneic cells were given: it did not occur spontaneously or on giving H-2 incompatible cells or on giving compatible material by an inappropriate route. The results accord with hypotheses that (1) osteoclasis of scaffoldtype woven bone is impaired in mi mi, (2) that osteoclastic cells are derived through circulating monocytes from hematopoietic stem cells, and (3) in mi mi this defect can be overcome by a transplant of normal hemopoietic stem cells.

Age Factors↗
PubMedDate not supplied

Microphthalmia (mi) mice display an aberrant bone trace element composition.

It has been recognized that bone trace element composition analysis provides clues when analyzing bone-related physiological conditions. Increasing numbers of bone-related genetic diseases have been identified recently. In this study, we have analyzed bone trace element composition in a genetic mutant animal model. Mutations in the mouse microphthalmia (mi) gene affect the development of a number of cell types, including melanocytes, mast cells, and osteoclasts. Previous studies have shown that different alleles of the mi locus show osteopetrosis. In order to gain insights into the effects of a particular genetic defect on bone trace element composition and bone structure, we performed bone trace element composition analysis using inductively coupled plasma atomic emissions spectrometry (ICP-AES). Marked changes in bone trace element levels were found in vertebrate bones of mi mutant mice. The implications and possible applications of bone trace element analysis will be discussed in this article.

Animals↗
PubMed1993

PKC gamma gene expression is delayed in postnatal central nervous system of mi/mi mice.

In the central nervous system (CNS), the expression of protein kinase C (PKC) genes is strictly controlled by the developmental stage. We have examined the expression of PKC genes (cPKC alpha, beta, gamma, and nPKC delta, epsilon) in the process of the postnatal development in normal (+/+) C57BL/6 and microphthalmic (mi/mi) C57BL/6 mouse brains by Northern blotting and in situ hybridization. By Northern blotting, the expression level of cPKC gamma mRNA in mi/mi mice was significantly lower than that in +/+ littermates at d 9, 13, and 17. By in situ hybridization analysis, cPKC gamma mRNA-positive cells were detected in hippocampal and Purkinje cells in +/+ and mi/mi mice, but the magnitude of the signals in mi/mi mice was lower than that of +/+ mice, and the number of positive cells was smaller, whereas other isozymes (cPKC alpha, beta, and nPKC delta, epsilon) showed no significant difference between normal and mi/mi mice. The neuronal morphometric analysis by anti-P400 antibody revealed the same number and expression level of P400 protein in cerebellar Purkinje cells compared with +/+ mice. These results indicate that the deficiency of mi gene product causes the delayed expression of the cPKC gamma gene.

Animals↗
PubMed1998

Central nervous system involvement in incontinentia pigmenti: cranial MRI of two siblings.

Incontinentia pigmenti is an uncommon neurocutaneous syndrome characterised by skin lesions, dental and ocular abnormalities and central nervous system involvement. We report the cranial MRI findings in two sisters with this condition. These include hypoplasia of the corpus callosum, enlargement of the lateral ventricles and periventricular white-matter lesions. One girl also had unilateral microphthalmia and rostral agenesis of the corpus callosum, a feature not previously described.

Agenesis of Corpus Callosum↗
PubMed1998

An atretic parietal cephalocele associated with multiple intracranial and eye anomalies.

We present the cranial MRI findings in a 4-month-old girl with an atretic parietal cephalocele associated with multiple cerebral and ocular anomalies including lobar holoprosencephaly, a Dandy-Walker malformation, agenesis of the corpus callosum, grey-matter heterotopia, extra-axial cysts in various locations, bilateral microphthalmia and a retroocular cyst.

Abnormalities, Multiple↗
PubMed2005

Genetic and phenotypic analysis of Tcm, a mutation affecting early eye development.

Tcm (total cataract with microphthalmia) is an autosomal dominant mouse eye mutation. Heterozygous Tcm/+ mice are born with several eye malformations including microphthalmia, retinal and iris dysplasia, total lens cataract, and ventral coloboma. The Tcm mutation was previously mapped to a 26-Mb region on Chr 4 between D4Mit235 and D4Mit106. In this study, we characterize the Tcm/ Tcm homozygous mutant and find they are viable but severely microphthalmic. The developing eye in the Tcm/Tcm homozygote shows defects during early eye development, before formation of the optic cup. Further genetic mapping reduced the Tcm critical region to a 1.3-Mb region bordered by SNPs rs3666764 and rs3713818. This critical region contains two known genes (Asph and Gfd6) and three predicted genes, all of which are positional candidates for Tcm. Sequence analysis of Tcm genomic DNA revealed no mutations in the coding regions and splice site junctions of the five candidate genes. These results indicate that the causitive Tcm mutation falls within a noncoding regulatory region of one of the five candidate genes or in an undescribed gene.

Aging↗
PubMed1998

The rat microphthalmia-associated transcription factor gene (Mitf) maps at 4q34-q41 and is mutated in the mib rats.

The rat gene encoding the microphthalmia-associated transcription factor (Mitf) was assigned to rat Chromosome (Chr) 4q34-q41, as well as the Gata2 and Mem1 genes. Rat Chr 4 is homologous to mouse Chr 6 and human Chr 3, which carry the Mitf (MITF) gene in these species (MMU 6, 40.0 cM, and HSA 3p14.1-p12.3). mib/mib rats, which are characterized by depigmentation, microphtalmy, osteopetrosis, and neurological disorders were shown to bear a deletion covering several kilobases of genomic DNA in the Mitf gene and to lack Mitf mRNA. The Mitf mutation in the mib/mib rats is thus very likely to be a Mitf null mutation, causing a phenotype similar to the one observed in the miVGA-9 mice, but including osteopetrosis as an additional feature.

Animals↗
PubMed2003

[Treatment of congenital clinical anophthalmos with high hydrophilic hydrogel expanders].

INTRODUCTION: Children presenting with congenital anophthalmos usually develop a smaller bony orbit, a constricted mucosal socket, and a shortened eyelid fissure. This causes problems when fitting these patients with a prosthesis. Clinical evaluation of the Wiese self-inflating hydrogel expanders has demonstrated their ability to expand the socket and eyelid fissure for inserting a more realistic prosthesis in shorter periods of time. PATIENTS AND METHOD: The study included 13 consecutive anophthalmic patients, eight unilateral and five bilateral. Each patient received a hemispherical osmotic tissue expander in the rudimentary mucosal socket and later a sphere implanted in the deeper soft orbital tissue. RESULTS: The use of hydrogel expanders enlarged the lid and palpebral fissure in all children, with good cosmetic results. It allowed insertion of custom-made glass prostheses with good cosmetic appearance very early in life. Growth of the bony orbit may be stimulated successfully by these expanders in the soft orbital tissue. CONCLUSIONS: The enlargement of constricted mucosal sockets and short palpebral fissures using self-inflating hydrogel expanders is a new and successful concept in treating congenital anophthalmos.

Anophthalmos↗