Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MICROPHTHALMOS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,027 records · Page 57Linked to original sources
PubMed1997

Diurnal fluctuation in the enzyme activity and the messenger RNA level of pineal serotonin N-acetyltransferase in normal and hereditary microphthalmic rats.

The enzyme activity and the messenger RNA level of pineal serotonin N-acetyltransferase were more than 20- and 50-fold higher, respectively, in the dark period than in the light period in normal rats. In hereditary microphthalmic rats, however, the serotonin N-acetyltransferase activity and its mRNA level did not undergo a great diurnal change through the light and dark periods. These results indicate that the diurnal rhythms of the activity and the mRNA level of serotonin N-acetyltransferase are not detected in the pineal gland of hereditary blind rats, suggesting free-running rhythms in individual animals due to desynchronization of their circadian rhythms by a lack of their optic nerve.

Animals↗
PubMed2005

Congenital bilateral severe microphthalmia with mental retardation and cerebral palsy: chromosome aberration, 46, XY, t (2;6)(q31;q24).

Congenital bilateral anophthalmia and microphthalmia are rare conditions, with overall prevalence in one study set at 1.0 per 10,000 births. We report here a case of congenital bilateral severe microphthalmia with mental retardation and cerebral palsy. The patient was man aged 38 years with a chromosome aberration, namely a balanced translocation: 46, XY, t (2;6)(q31;q24). He had no other malformations apart from the severe microphthalmia. CT of the head showed no significant abnormal findings in the brain, but rudimentary eyeballs and external ocular muscles in the bilateral orbits. There was no family history of anophthalmia, microphthalmia, mental retardation or cerebral palsy. His mother had not used any medications or excessive alcohol during gestation. Putative genes of anophthalmia and microphthalmia reported to date include PAX6 (Glaser T et al 1994) and CHX10 (Ferda Percin E et al 2000). Further, some loci of these conditions have been reported (Graham CA et al 1991; Bessant DAR et al 1998; Morle L et al 2000: Forrester S et al 2001: Ng D et al 2002). To our knowledge, however, this is the first report of nonsyndromic microphthalmia or anophthalmia with chromosome 2q31 or 6q24 aberration. We consider that the putative gene may be located on the brake points of chromosome 2 and 6.

Abnormalities, Multiple↗
PubMed2000

The microphthalmia transcription factor regulates expression of the tartrate-resistant acid phosphatase gene during terminal differentiation of osteoclasts.

The defective terminal differentiation of osteoclasts in mice homozygous for the mi allele of the microphthalmia transcription factor (MITF) gene implies that MITF plays a critical role in regulating gene expression during osteoclast ontogeny. To begin addressing the role of this transcription factor in the osteoclast, target genes need to be identified. In the present work, several lines of evidence show that the gene encoding the enzyme tartrate-resistant acid phosphatase (TRAP) is a target of MITF. Analysis of osteoclasts in vivo in the embryonic forelimb showed that MITF and TRAP RNA were coexpressed in a dynamic pattern during the process of endochondral ossification of long bone. Primary osteoclast-like cells (OCLs) produced from mi/mi mutant mice expressed TRAP messenger RNA (mRNA) at 8-fold lower levels than in OCLs derived from normal mice, indicating a direct link between MITF function and TRAP expression. The activity of mouse TRAP promoter-reporter genes was assayed in the primary OCLs by DNA-mediated transfection, and this activity was shown to depend on a conserved sequence (GGTCATGTGAG) located in the proximal promoter. Recombinant MITF protein recognized specifically this conserved sequence element. Expression of a TRAP promoter-green fluorescent protein (GFP) transgene mimicked the expression of the endogenous TRAP gene during differentiation of osteoclast-like cells, and the expression of the transgene was decreased 8-fold when placed into the mutant mi/mi background. These results are consistent with a role for MITF in gene expression during terminal differentiation of the osteoclast and will allow osteoclast-specific mechanisms of gene regulation to be studied in greater detail.

Acid Phosphatase↗
PubMed2003

Overexpression of RANKL implicates IFN-beta-mediated elimination of B-cell precursors in the osteopetrotic bone of microphthalmic mice.

The microphthalmic (mi) mouse possesses a dominant negative mutation in the microphthalmia-associated transcript factor (MITF) transcription factor. These animals are characterized by reduced numbers of peripheral mast and natural killer (NK) cells, are osteopetrotic because of osteoclast reduction and malfunction, lack functional melanocytes, and are deficient for maturing B-cells within the bone marrow. Granulocyte precursor cells, however, are functionally maintained within the mi bone marrow. A central question has been whether the B-cell deficiency of the mi mouse marrow is caused by the absence of an MITF-controlled gene product or because of the compromised, osteopetrotic environment. In this report, we examined mi marrow by performing transcriptional mapping analyses of candidate genes whose products are instrumental for functional osteoclast and B-cell development. Surprisingly, the expression of a subset of such genes including RANKL, stromal-derived factor (SDF-1), B-cell lymphotactin chemokine (BLC), and RANK was dramatically enhanced in the mi marrow. Normal and mutant marrow were also analyzed by subtractive transcript cloning, which identified a number of known and unknown genes with altered transcriptional activity. One such unknown mouse gene possesses a human counterpart that is interferon-beta (IFN-beta) inducible, suggesting the osteopetrotic marrow is enriched for IFN-beta, a cytokine that is known to eliminate B-cell precursors. A model is proposed suggesting excess RANKL sets off a cascade of cytokine production including IFN-beta that leads to the preferential elimination of B-cell precursors in the marrow of osteopetrotic marrow.

Amino Acid Sequence↗
PubMed1999

True hermaphroditism associated with microphthalmia.

A 4-year-old boy with an undescending left testis, penoscrotal hypospadia and bilateral microphthalmia was admitted to our hospital. Chromosome analysis revealed a karyotype of 46, XX del(x)(p2 2,31) and the sex-determining region of the Y chromosome (SRY) was negative. The right testis was located in the scrotum and a left cystic ovary-like gonad, a salpinx and a unicorn uterus were found in the left inguinal canal. Histologically the gonad was an ovotestis in which primordial follicles covered infantile seminiferous tubules. Microphthalmia is observed in some congenital syndromes caused by interstitial deletion of the X chromosome. This case suggested that the short arm of the X chromosome was involved in the differentiation of the gonad. Very closely located follicles and infantile seminiferous tubules indicated that induction of meiosis in the fetus was controlled by the local microenvironment in follicles and seminiferous tubules, and not by the systemic hormonal condition.

Child↗
PubMed1996

Morphological changes in the hypothalamic suprachiasmatic nucleus and circadian rhythm of locomotor activity in hereditary microphthalmic rats.

Analysis of circadian locomotor activity, Golgi-Cox impregnation, and immunohistochemistry were studied on the hereditary microphthalmic rat which congenitally lacked the optic nerve. These blind rats showed free-running circadian rhythms in their locomotor activities. Both the normal and microphthalmic rats had similar ultradian rhythms in addition to circadian rhythms. The neuronal cell population and volume of the hypothalamic suprachiasmatic nucleus (SCN) of the microphthalmic rats were 66% and 71% of those in normal rats, respectively. The number of SCN neurons containing vasoactive intestinal peptide-like immunoreactive substance was dramatically decreased to 35% of that in normal rats. Golgi-Cox impregnation revealed that three types of neurons in the SCN of the microphthalmic rats were consistently distinguished as observed in normal rats. Although there were no changes in the numbers of primary dendrites of the SCN neurons in the microphthalmic and normal rats, the number of secondary and tertiary dendrites in the SCN of the microphthalmic rats was smaller than that of normal rats. These observations suggest that the retinal input may be important for normal morphological formation of the SCN during development, but not for the generation of circadian rhythms and ultradian rhythms.

Animals↗
PubMed1997

Little or no response to 24-hr water-deprivation of Fos-like immunoreactivity in vasopressinergic magnocellular neurons in the hypothalamus of hereditary microphthalmic rats.

In normal rats, 24-hr water-deprivation was found to cause a significant increase in the plasma concentration of arginine vasopressin (AVP), and marked induction of Fos in the AVP-positive magnocellular neurons in the paraventricular nucleus (PVN) and the supraoptic nucleus (SON) of the hypothalamus. On the other hand, 24-hr water-deprivation also caused a significant increase in the plasma AVP concentration in hereditary microphthalmic rats, but much less than in normal rats. Consistent with this, the extent of induction of Fos in the nuclei of the PVN and SON of these rats was lesser than in normal rats. These results suggest that hereditary microphthalmic rats have a defect or decrease in the response to water-deprivation of vasopressinergic magnocellular neurons in the PVN and SON.

Animals↗
PubMed2001

Immunohistochemical detection of tyrosine hydroxylase and concentrations of monoamines in the substantia nigra and hypothalamus of hereditary microphthalmic rats.

We compared tyrosine hydroxylase immunoreactivity in the substantia nigra and hypothalamus of hereditary microphthalmic rats with that of normal rats. A considerable number of neuronal cell bodies expressing tyrosine hydroxylase were present in the substantia nigra of the microphthalmic mutant as well as normal rats. Neuronal cells positive for tyrosine hydroxylase in the hypothalamus were fewer than in the substantia nigra in both rats. The concentrations of monoamines (dopamine, noradrenaline, adrenaline, and serotonin) in the substantia nigra and hypothalamus in the microphthalmic mutant were approximately the same as those of normal rats, although the diurnal fluctuation of a few monoamines was observed in normal rats. These results suggest that the metabolic aspects of catecholamine in the substantia nigra and hypothalamus of the microphthalmic mutant rat do not markedly differ from those of normal rats.

Animals↗
PubMed1988

Genetical and histological studies on a mouse displaying microphthalmia and cataract.

A male mouse displaying bilateral microphthalmia and cataract was found among the offspring of pregnant Slc: ICR mouse treated intraperitoneally with 10 mg/kg methylnitrosourea on gestational day 4. This mutant has been maintained by brother-sister mating. By the mating test with normal Slc: ICR mice, this character was revealed to be inherited by an autosomal single recessive gene. Linkage test with the brown locus showed that this mutant gene is linked with the B gene and mapped on chromosome 4. The histological study of the eyes of adult mutant mice revealed various abnormalities all over the eyes, especially in the lens and neural retina. Embryologically, the mutant mice showed persistent connection between the lens vesicle and the surface ectoderm by a cellular stalk, and also the formation of retinal infolding, in the early stages of eye development. Both were considered to be responsible for the consequent abnormal development and degradation of the lens. These results suggest that the mutant mouse we found may be an allele of the dysgenetic lens (dyl) reported by Sanyal and Hawkins.

Animals↗
PubMed1988

Morphological and genetic characteristics of the open-eyelid mutant spontaneously occurring in NC-strain mice.

A heritable open-eyelid mutant which arose spontaneously in the NC strain of mouse in 1982 has been maintained as the NC-eob line through brother-sister matings. When the line exceeded the 12th generation, its reproductive capabilities were initially compared with those of the NC strain. Then eye abnormalities were investigated morphologically and genetically. Although most of the reproductive parameters in the NC-eob line were comparable to those in the NC strain, a significant decrease was observed in the mean number of pups delivered, and the viability of pups at 7 days of age was reduced to 55%. The eyelids of pups were widely open at birth. The exposed cornea dried within a few hours and a bloody exudate appeared around the margin of the eyelids. At 1 day of age, the eye opening was smaller in size and covered with a scab. Histological examination demonstrated apparent inflammatory changes in the cornea and conjunctiva. At 21 days of age, the eyes revealed opacity, a rough surface, and microphthalmia. Histological findings in the cornea, such as keratosis and vascularization, coincided with the eye opacity. The weight and size of the eyeballs were almost the same as those in normal NC pups. However, a significant decrease in the length of the palpebral rima was evident and this was considered to be the cause of the microphthalmia. The results of genetic analysis indicated that these eye abnormalities were caused by an autosomal recessive gene, eob. These results suggested that the eob gene might be a new mutation manifesting semi-lethality as a pleiotropic effect.

Animals↗
PubMed1992

[Morphometric and immunohistochemical studies of the suprachiasmatic nucleus in the hereditary microphthalmic rat].

Morphometric and immunohistochemical analyses of the suprachiasmatic nucleus (SCN) were performed on hereditary microphthalmic rats. In normal rats, the number of cells and the volume of the SCN were 11, 631 and 6.7 x 10(-2) mm3 (an average taken from 12 SCNs). However, the neuronal population and volume of the SCN in hereditary microphthalmic rats were 7,450 and 4.5 x 10(-2) mm3 (an average taken from 14 SCNs), respectively. There were no significant differences in the size of neurons between normal and microphthalmic SCN neurons. Immunohistochemical studies showed that a considerable number of antivasopressin positive neurons were present in microphthalmic rats, despite their lack of the optic nerve. However, further detailed studies revealed that the number of antivasopressin positive neurons present in microphthalmic rats was only 68% of those found in normal rats. These findings suggest that the complete development of the SCN and vasopressin neurons depends on the visual input.

Animals↗
PubMed1994

Critical period for induction of ocular anomalies produced by soft x-ray irradiation (4.6 Gy) in the rat F1 offspring.

A minimal dose of soft x-ray irradiation of 4.6 Gy is expected to produce ocular anomalies on gestational day 9. A study was performed to determine whether ocular anomalies are induced in rat F1 offspring at this dose level on gestational days 6, 7, 8, 9, 10, and 11. Eyes were examined during postnatal week 5 using indirect ophthalmoscopy and biomicroscopy. Anophthalmia (1.3% and 12.1%), microphthalmia (3.8% and 6.9%), iris coloboma (3.8% and 6.9%) and choroidal coloboma (2.5% and 8.6%) were observed in the gestational day 8 and 9 treatment groups, respectively. There were no treatment-related ophthalmological abnormalities at the other time points. It is concluded that the most sensitive period for induction of ocular anomalies by soft x-ray irradiation at a dose of 4.6 Gy under these experimental conditions is during gestational days 8 and 9, and that gestational day 9 appears to be more sensitive than day 8.

Animals↗
PubMed2005

Atypical Hallerman-Streif syndrome: a case report.

Hallerman Streif syndrome is a rare congenital disorder characterized by dyscephaly, dental anomalies, proportionate nazism, hypotrichosis, cutaneous atrophy limited to the head, bilateral congenital cataracts and bilateral microphthalmia. Despite the marked craniofacial characteristics and oral findings, a relative lack of reports in the dental literature has been noted. In this article, a case of a 8 year old boy with dental problems is described.

Abnormalities, Multiple↗
PubMed1985

[Teratogenicity study on halopredone acetate in rats].

A teratogenicity study of halopredone acetate (THS-201), a synthetic corticosteroid, was carried out using Jcl: Wistar rats. Pregnant rats were treated subcutaneously in doses of 0.1, 0.5, 2.5 and 12.5 mg/kg/day, from day 7 to day 17 of gestation. Two-thirds of pregnant rats were killed on day 20 of gestation to examine the development of fetuses, and remaining rats were allowed to litter naturally in order to investigate the postnatal development of offspring. The results obtained from the present study were as follows. During the gestation and lactation periods, there occurred a decrease in the maternal body weight gain in 2.5 and 12.5 mg/kg groups. No influences of THS-201 administration were observed on gestation, delivery and lactation of dams. No external, visceral and skeletal anomalies attributable to THS-201 were observed in the fetuses. THS-201 administration did not have any influences on viability and development, various functions such as reflex response, learning and reproductive performance of F1 generation, and further on development of F2 generation. Therefore, it was concluded that the non-effect dose of THS-201 for the reproduction of dams and development of F1 generation was 12.5 mg/kg/day.

Abnormalities, Drug-Induced↗