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At least 1,513 records · Page 84Linked to original sources
PubMed1994

Microphthalmia and associated abnormalities in inbred black mice.

Although microphthalmia and anophthalmia develop in many animals, they are a consistent and frequent finding in inbred and congenic strains of C57BL mice. Many investigators fail to take account of an incidence that may be as high as 12%, and this may lead to misinterpretation of experimental results. Further confusion may arise from the higher frequency in female mice and from the effects of various environmental and breeding conditions. In anophthalmic and severely microphthalmic mice, there is faulty tear drainage function, which often leads to ocular infections. It should be emphasized that these infections are a function of the ocular malformations arising from the genetic characteristics of C57BL strains and do not represent a failure in proper animal husbandry practices. Histologic studies confirm the consistency and the variability of the ocular findings in these strains. The eye abnormalities may be unilateral or bilateral and, for unexplained reasons, have a strong predilection for the right eye. Microphthalmia may be subtle and clinical anophthalmia may actually represent severe microphthalmia. Accordingly, any conclusions for these inbred strains regarding the eyes should be accompanied by careful microscopic examination of all animals. The most common findings include central corneal opacities, iridocorneal and corneal-lenticular adhesions, abnormal formation of the iris and ciliary body, cataracts, extrusion of lens cortical material with dispersion throughout the eye, failure of vitreous development, and retinal folding. The incidence of all of these findings is increased by exposure to alcohol at critical stages of embryogenesis. Mesodermal dysgenesis of the anterior segment in human eyes mimics the findings seen in inbred C57BL strains of mice, although severe microphthalmia or anophthalmia is less commonly seen. These similar human findings have been associated with a complexity of chromosomal abnormalities and inheritance patterns. Development of the fetal alcohol syndrome in human eyes also provides a phenocopy of the anterior segment abnormalities of mice and of the human familial syndromes. The events, which result in abnormalities in mice and humans, all center around the time in embryogenesis when the optic cup and lens vesicle are developing. In all instances, the lens tends to be smaller than normal and may be displaced in position with relation to the optic cup. This relationship between lens and optic cup is critical in normal development of other ocular structures, including the iris, ciliary body, vitreous, and retina.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMedDate not supplied

[The importance of the early diagnosis of primary persistent hyperplastic vitreous].

The early diagnosis of PHPV is often difficult to be established, because of the frequent opacification of the ocular transparent media. So the echography and the computerized tomography, the early surgical intervention using up-to-date techniques in vitreous surgery is imposed, in order to maintain functionally or anatomically the affected globe.

Cataract↗
PubMed1994

The mouse tyrosinase gene. Promoter modulation by positive and negative regulatory elements.

Tyrosinase, the key enzyme in melanin synthesis, is expressed specifically in pigment-producing cells. Studies with transgenic mice and gene transfer experiments have demonstrated that the 270-base pair 5'-flanking sequence of the mouse tyrosinase gene leads to weak but cell type-specific and developmentally regulated expression. To elucidate the underlying transcriptional control, we focused on the identification of cis-acting elements within this 270-base pair minimal promoter. We also addressed the potential role of promoter elements in the control of cAMP regulation of the tyrosinase gene. Deletion and linker scanning mutagenesis revealed that promoter activity is modulated by two positive elements and one negative element. One of the positive elements includes the M-box, a sequence motif shared with the promoter of two other melanocyte-specific genes, trp-1 and trp-2. Cotransfection experiments provide evidence that a basic helix-loop-helix-zipper protein, encoded at the microphthalmia gene locus, transactivates the tyrosinase promoter, probably by binding to the M-box. Activating cis elements are bound by nuclear factors in vitro and confer increased expression to a reporter gene both in melanoma cells and in fibroblasts. We therefore suggest that the positive promoter elements modulate tyrosinase expression rather than determine cell specificity in vivo, whereas the negative element acts cell type specifically.

3T3 Cells↗
PubMed1994

Aberrant visual pathways in microphthalmic mice.

We report results obtained in the microphthalmic strain of mice 944. Heterozygotes appear normal, but they produce litters in which typically between 2 and 5 offspring exhibit microphthalmia. As a result these animals are blind. Our investigations using the fluorescent tracer DiI show that in microphthalmic mice there is a small compensation for the missing retinal input by terminals or axon collaterals originating in the somatosensory thalamus. These morphological findings agree with somatosensory responses recorded in the visual cortex (EEG recordings).

Animals↗
PubMedDate not supplied

Holoprosencephaly anomaly with nasal and premaxillar agenesis (possibly autosomal recessive type).

A one-day-old male infant with cleft lip and palate, microcephaly, hypotelorism, microphthalmia and absence of the nose is presented. The intermaxillar segment and nasal bone structure were not seen on radiological examination of the skull. Chromosome examination showed a 46, XY karyotype. On postmortem examination, the cerebrum was seen to be a single lobe. Olfactory nerves, corpus callosum and nasal formation, besides the septum were absent. The first and second ventricles were formed as a single ventricle. These findings were compatible with alobar holoprosencephaly.

Abnormalities, Multiple↗
PubMed1975

[Ocular findings in syndroma of Schimmelpenning-Feuerstein and Mims (author's transl)].

This is a description of a male patient, now 8-years-old, with the syndrome described by Schimmelpennig-Feuerstein and Mims. Characteristic for this clinical picture, which is classified as a phacomatosis, are a striated and sponge-like naevus sebaceus, disorders of the central nervous system taking the form of debility and epileptic attacks, and multiple anomalies of the eyes, such as microphthalmus, coloboma of the eyelids and optic nerve with ablatio falciformis, as well as dermoids and teratomas of the conjunctiva.

Child↗
PubMed1993

Type III syndactyly and oculodentodigital dysplasia: a clinical spectrum.

A newborn male patient presented with complete cutaneous syndactyly of fingers 3-5 in the left hand and fingers 4-5 in the right hand. The mother and maternal grandmother were born with the same hand malformation. Facial features in the mother showed a thin nose and small teeth; eyes were normal. In the grandmother, teeth had been very small with enamel hypoplasia; eyes were normal. The present family provides evidence of the variable expression in oculodentodigital dysplasia. Inheritance is autosomal dominant.

Abnormalities, Multiple↗
PubMed1993

Congenital cataract, microphthalmia and septal heart defect in two generations: a new syndrome?

The association of congenital cataracts, microphthalmia and heart disease is well recognized in fetal rubella, but genetic causes are comparatively rare and recurrence risks are usually low. We describe a woman with an atrial septal defect, bilateral congenital cataracts, unilateral microphthalmia and minor dysmorphic features, originally attributed to an unidentified infection in utero, whose daughter has a similar constellation of heart, eye and facial abnormalities. This may represent a new dominantly inherited syndrome.

Abnormalities, Multiple↗
PubMed1993

A sporadic case of Lenz microphthalmia syndrome.

We present a sporadic case of colobomatous microphthalmia associated with multiple congenital anomalies. Our purpose is to add a new case of Lenz microphthalmia syndrome to the literature and to draw attention to the typical pattern of facial features of this disease.

Abnormalities, Multiple↗
PubMedDate not supplied

[The expression of the mutant gene mi in mouse aggregation chimeras].

Using aggregation of 8-cell embryos belonging to two mouse strains, we produced 17 chimeras, mi/mi<==>+/+ (3 organisms), mi/+<==>+/+ (9 organisms), and +/+<==>+/+ (5 organisms), that achieved the age of 30 days. Chimerism was identified by mosaic pigmentation of coat and retinal pigment epithelium (RPE). All mi/mi<==>+/+ chimeras suffered from microphthalmia. Disturbances of eye development in these mice were similar to those in mi/mi animals. In all three chimeras, pigmentation of RPE and choroid was represented with alternating pigmented and depigmented patches. Mosaic RPE pattern probably resulted from the effects of para-orbital mesenchyme cells of different genotypes, +/+ or mi/mi. These findings confirm our earlier data that mutant alleles of the mi locus affect ectomesenchyme (neural crest) cells playing an important role in normal RPE development. Coat pigmentation in mi/mi<==>+/+ chimeras had the same spotted pattern as in mi/+ heterozygous mice. Hence, the gene mi functions in melanoblasts, but dermal and epidermal mi/mi cells do not suppress migration, proliferation, and differentiation of +/+ melanoblasts. The mi/mi dermal cells do not interfere with the expression of the gene A. Despite the high proportion of mi/mi cells (58 to 80%), bone resorption and eruption of teeth in mi/mi<==>+/+ chimeras proceeded as in normal animals.

Alleles↗
PubMed1993

Microphthalmia and cerebral atrophy induced in mouse embryos by infection with murine cytomegalovirus in midgestation.

Microphthalmia and cerebral atrophies were induced in mouse embryos after injection of murine cytomegalovirus (MCMV) into the conceptus at midgestation. The concepti of ICR mice on day 8.5 of gestation were injected with MCMV through the uterine wall, then pregnancies were allowed to continue. On day 15.5 of gestation, microphthalmia was observed in 19.2% of the MCMV-injected embryos (1 x 10(4) plaque-forming units). As the survival rate decreased when pregnancies were allowed to continue further, incidence of microphthalmia decreased, whereas cerebral atrophies, determined by examining the histological sections, were observed in 17.6% of the surviving mouse fetuses on day 18.5 of gestation. Microphthalmia was confirmed by microscopically measuring the eyes on the serial coronal sections. There were two types of microphthalmia: one with marked hypoplastic eye with periglobular mesenchymal proliferation, the other with small eye and lens without the mesenchymal proliferation. Immunohistochemical analysis was performed using antibodies specific to the nuclear antigen of MCMV. Viral antigen-positive cells were widely distributed in the mesenchymes around the oral and nasal cavities and in the mesenchymes around the brain, especially in the endothelial cells of the vessels and the perivascular mesodermal cells. In the eyes, viral antigen-positive cells were observed in mononuclear blood cells in the cavities of the vitreous bodies. These results suggest that the primary target of congenital cytomegalovirus infection may be the mesenchymal cells; then the infection extends to the eyes and brain. In addition, the mesenchymal infection may also disrupt their organogenesis, resulting in microphthalmia and cerebral atrophy. This experimental system may provide a model similar to congenital cytomegalovirus infection in humans.

Animals↗