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PubMed1995

Development and physical analysis of YAC contigs covering 7 Mb of Xp22.3-p22.2.

A total of 54 YAC clones have been isolated from the region of Xp22.2-p22.3 extending from the amelogenin gene locus to DXS31. Restriction analysis of these clones in association with STS contenting and end clone analysis has facilitated the construction of 6 contigs covering a total of 7 Mb in which 20 potential CpG islands have been located. Thirty new STSs have been developed from probe and YAC end clone sequences, and these have been used in the analysis of patients suffering from different combinations of chondrodysplasia punctata, mental retardation, X-linked ichthyosis, and Kallmann syndrome. The results suggest that (1) the gene for chondrodysplasia punctata must lie between the X chromosome pseudoautosomal boundary (PABX) and DXS1145; (2) a gene for mental retardation lies between DXS1145 and the sequence tagged site GS1; and (3) the gene for ocular albinism type 1 lies proximal to the STS G13. The CpG islands within the YAC contigs constitute valuable markers for the potential positions of genes. Genes found associated with any of these potential CpG islands would be possible candidates for the disease genes mentioned above.

Albinism, Oculocutaneous↗
PubMedDate not supplied

Anophthalmia and benomyl in Italy: a multicenter study based on 940,615 newborns.

Following the report on clusters of anophthalmia and microphthalmia in England and Wales and their possible relation to the pesticide Benomyl, we analyzed the situation in Italy for the period 1986 to 1990 using data from the Italian registries of congenital malformations and national data on Benomyl use. Of 940,615 consecutive births, 33 cases of clinical anophthalmia and 78 cases of microphthalmia were reported (birth prevalence: 0.35 and 0.83/10,000). Birth prevalence by region for 18 of Italy's 20 political regions was evaluated for the two malformations, grouped together after exclusion of defects associated with chromosomal anomalies, no dishomogeneity in space or time among registries or among regions was observed for the study period. In no region was a statistically significant difference identified between observed and expected overall birth prevalence. Correlation analysis between the prevalence of micro/anophthalmia and Benomyl use by region showed a negative, nonsignificant coefficient, and an inverse correlation was found when the 18 regions were divided into four groups by increasing levels of Benomyl use. Parental occupation in agriculture did not seem to be associated with micro/anophthalmia when compared to a control group affected with isolated prearicular tags (odds ratio 0.63; CL 0.07-2.52). On the basis of these results, though the limits intrinsic to ecologic correlation studies must be taken into account, an association between Benomyl use and congenital micro/anophthalmia appears to be unlikely.

Anophthalmos↗
PubMed1985

Fusion disability of embryonic osteoclast precursor cells and macrophages in the microphthalmic osteopetrotic mouse.

Osteoclast formation in the microphthalmic osteopetrotic (mi) mouse was studied from very early embryonic to newborn stages. Embryonic and fetal milmi osteoclasts, generated during the period before bone marrow is formed in the long bones, were predominantly mononuclear and lacked ruffled borders. These cells did, however, show many osteoclastic morphologic and functional properties, such as an abundance of mitochondria, positive succinic dehydrogenase and acid phosphatase reactions, and close contact with and resorption of the calcified cartilage matrix (though diminished). These osteoclastic mononuclear cells appeared in vivo as well as in organ cultures of fetal metatarsal bones with their intact periostea. They also were observed in cocultures of periosteum-free fetal metatarsal bones, with several extraneous sources of osteoclast precursors: yolk sacs and abdominal regions of 9- and 11-day-old embryos, fetal livers, and precultured mononuclear phagocytes isolated from the fetal liver. In contrast, +/+ osteoclasts were always multinuclear, functioned normally in resorbing the calcified cartilage matrix, and had ruffled borders in vivo as well as when derived from the above-mentioned sources. Fetal liver-derived milmi macrophages also failed to form multinuclear foreign body giant cells as opposed to +/+ macrophages in granulomas on implanted pieces of Melinex. The fusion failure of cells derived from embryonic and fetal extramedullary milmi monocyte/macrophage sources contrasted with the occurrence of multinuclear osteoclasts and foreign body giant cells derived from precursors from the bone marrow in young milmi mice. We conclude that the fusion defect of milmi osteoclast precursor cells is already present in their ancestry in blood cell-forming organs of very young embryos and that these cells differentiate into mononuclear osteoclasts that function inefficiently in prenatal bone. We presume that in fully developed bone marrow, local factors are favorable for abolishing the fusion defect.

Animals↗
PubMed1988

A morphologic study of osteoclasts isolated from osteopetrotic microphthalmic (mi/mi) mouse and human fetal long bones using an instrument permitting combination of light and scanning electron microscopy.

Cell surface structures of isolated osteopetrotic (mi/mi) and normal murine (+/+ and +/mi) and human osteoclasts were examined in a microscope combining light and scanning electron microscopy (LM/SEM). Tartrate-resistant acid phosphatase (TrAP) was used as an histochemical osteoclast marker. In osteopetrotic bone, as in normal murine bone, TrAP activity was exclusively seen in osteoclasts and preosteoclasts and was therefore judged a suitable marker for identification of isolated osteoclasts. A method was developed for preparation of LM/SEM specimens from osteoclast-enriched cell suspensions. In the LM/SEM isolated osteoclasts were easily recognized in the LM mode by TrAP contents. In specimens prepared from murine cells, but not human cells, LM identification of osteoclasts by TrAP was essential. This was in particular true for small, mononuclear, mi/mi osteoclasts. All osteoclasts examined had a villous appearance and were well spread over the glass substrate. There were no differences in cell surface morphology and in adherence to glass between osteopetrotic and normal osteoclasts.

Acid Phosphatase↗
PubMedDate not supplied

Neonatal reductions in osteoclast number and function account for the transient nature of osteopetrosis in the rat mutation microphthalmia blanc (mib).

We have examined the general and skeletal manifestations of osteopetrosis in a new, mild osteopetrotic mutation in the rat, microphalmia blanc (mib). Newborn mutant (mib) rats exhibit the typical skeletal deformities and sclerosis of osteopetrosis at birth, which are reduced significantly during the first postnatal month but don't disappear entirely up to 8 months later. Osteoclast numbers, staining for TRAP and TraATPase, and bone resorption are reduced in mutants during the first 2 postnatal weeks but improve by 1 month. In mutants, serum concentrations of calcium and phosphorus are normal, but 1,25(OH)2 D levels are higher at 1 week than those in normal littermates. Neonatally, mutants exhibit extramedullary hemopoiesis in the spleen. These results are interpreted to mean that the transient perinatal skeletal sclerosis in mib rats is caused by reduced production and function of osteoclasts in this period. The recent description of transient, perinatal osteopetrosis in a child suggests that analyses of the early differences between mild and severe animal mutations might distinguish those children with osteopetrosis who need treatment from those who do not.

Aging↗
PubMed1995

Bone metabolism in the osteopetrotic rat mutation microphthalmia blanc.

We have examined parameters of bone metabolism in a new mutation, microphthalmia blanc (mib), in the rat exhibiting a skeletal sclerosis at birth that improves with age. There were no significant differences in the rate of bone formation during the first postnatal month except a temporary reduction in mutants at 3 weeks that coincided with compromised nutrition at weaning. At birth the ruffled border in mutant osteoclasts was absent or poorly developed and mRNA analyses of mutant bone compared to normal bone showed significant reductions in the messages for the osteoclast-specific genes carbonic andydrase II and tartrate-resistant ATPase. These distinctive ultrastructural and molecular differences were not present 1 month later. These data show that the transient osteopetrosis in mib rats results from a perinatal reduction in ultrastructural and enzymatic features of active osteoclasts and is not complicated by elevations in bone formation. The molecular basis for both the production and resolution of these abnormalities deserves further study.

Adenosine Triphosphatases↗
PubMed2006

Early and late onset fetal microphthalmia.

OBJECTIVE: The purpose of this study was to present sonographic and pathologic findings in early and late onset fetal microphthalmia. STUDY DESIGN: Fetal sonography was prospectively performed in 30,989 consecutive pregnancies at 14 to 24 weeks' gestation. In addition, we retrospectively reevaluated US recordings of 4 fetuses from other hospitals, in which normal eyes were observed in early and midgestation and microphthalmia was diagnosed only in the third trimester of pregnancy or after birth. RESULTS: Microphthalmia was detected in 13 fetuses in the prospective group. Twelve of 13 had additional structural and chromosomal anomalies. Termination of pregnancy was performed in 12 cases. In the retrospective group of late onset microphthalmia we confirmed the normal eye measurements performed in the early and midpregnancy. Severe vision impairment or blindness was noted in 3 of these children, while the fourth pregnancy was terminated. CONCLUSION: Normal measurements of the fetal eyes in early and midpregnancy do not exclude the possibility of subsequent development of microphthalmia.

Age of Onset↗
PubMed2006

Normal patterns of déjà experience in a healthy, blind male: challenging optical pathway delay theory.

We report the case of a 25-year-old healthy, blind male, MT, who experiences normal patterns of déjà vu. The optical pathway delay theory of déjà vu formation assumes that neuronal input from the optical pathways is necessary for the formation of the experience. Surprisingly, although the sensation of déjà vu is known to be experienced by blind individuals, we believe this to be the first reported application of this knowledge to the understanding of the phenomenon. Visual input is not present in MT, yet the experiences he describes are consistent with reports in the literature of déjà vu occurrence in sighted people. The fact that blind people can experience déjà vu challenges the optical pathway delay theory, and alternative causes are briefly discussed.

Adult↗
PubMed2004

Electroretinographic assessment of retinal function in microphthalmia mutant mice.

The purpose of this study was to examine the effects of mutations in the mouse (Mus musculus) multi-allelic microphthalmia transcription factor (Mitf) gene on retinal function. Mitf mice provide a rare opportunity to assess retinal degeneration caused by defective retinal pigment epithelium (RPE). Electroretinography (ERG) was used to evaluate the functional state of the retina and to determine the role of the Mitf gene in visual function. Corneal ERGs were recorded with a steel wire in response to white flashes of light. Homozygous Mitf(Mi-wh)/Mitf(Mi-wh), Mitf(mi-sp)/Mitf(mi-sp) Mitf(mi-bws)/Mitf(mi-bws) and wild type mice in addition to Mitf(Mi-wh)/Mitf(mi-sp) compound heterozygous mutants were studied at 16 weeks of age. Although each animal was only tested once, multiple animals of each genotype were tested. The ERGs of Mitf(mi-sp)/Mitf(mi-sp) were found to be normal. All components of the ERGs of Mitf(mi-bws)/Mitf(mi-bws) mice were normal except the photopic b-wave and the scotopic c-wave, which were reduced in amplitude. The ERGs of Mitf(Mi-wh)/Mitf(Mi-wh) mice suggest they are probably blind. On the other hand, ERGs from Mitf(Mi-wh)/Mitf(mi-sp) mice were reduced in amplitude and delayed, indicating an RPE/photoreceptor defect. At 16 weeks post partum, Mitf(Mi-wh)/Mitf(mi-sp) mutants show evidence of rod-cone dystrophy. Surprisingly, Mitf(mi-bws)/Mitf(mi-bws) mice, which have a similar phenotype as Mitf(mi-vit) mice with respect to coat color and eye development, show mostly normal ERGs. The reduced scotopic c-wave in Mitf(mi-bws)/Mitf(mi-bws) mice, without reduction in the scotopic a-wave indicates an RPE defect without photoreceptor involvement in these mice.

Animals↗
PubMed2005

Massive gliosis of the retina: report of a case investigated by immunohistochemistry and clonality assays.

We report a rare case of massive retinal gliosis that developed in a 32-year-old woman who had been born with bilateral microphthalmia. The patient had recently noticed left ophthalmos and underwent total resection of the affected eyeball. Histologically, the vitreous body had been totally replaced by massively proliferated spindle cells, which had delicate fibrillary cytoplasm without nuclear atypia. Because the attenuated retinal pigment epithelium and intact sclera were preserved at the periphery of the tumor, the tumor was thought to be retinal in origin. Immunohistochemically, the spindle cells were strongly positive for glial fibrillary acidic protein and neuron-specific enolase and partly positive for S-100 protein. These findings led to a diagnosis of massive gliosis of the retina. Clonality analysis of the tumor using a human androgen receptor assay revealed the polyclonal nature of the proliferating spindle cells. This is the first documentation of the polyclonality of this disease.

Adult↗
PubMed2004

Integrated reconstructive strategies for treating the anophthalmic orbit.

INTRODUCTION: Anophthalmia may be congenital or acquired. Congenital anophthalmia refers to any orbit that contains a severely hypoplastic eye at birth (microphthalmia), or a complete absence of the globe due to failure of optic vesicle formation. In both those cases the aim of surgery is to stimulate adequate orbital growth. Acquired anophthalmic orbit may be due to trauma or tumour. In acquired forms the goal is restoration of orbital volume with adequate replacement of orbital contents. PATIENTS AND METHODS: In this study 28 patients (6 cases of congenital and 22 of acquired anophthalmia), were treated between October 1997 and August 2002, by applying protocols that are based on data from the literature. RESULTS: In 19 cases there were satisfactory results. Complications such as implant dislocation (3 cases), residual asymmetry (2 cases), and eyelid retraction required revisional surgery (4 cases). CONCLUSIONS: The different strategies applied for reconstructing the missing structures of the orbit in the congenital forms have given satisfactory results related to the type and complexity of the deformity. In rehabilitating a patient with an acquired anophthalmic orbit it is essential to ensure that the patient has realistic expectations regarding a final prosthesis. Interaction of the various healthcare professionals is also essential to help the patient and so develop new prosthetic devices as well as innovative methods for socket reconstruction.

Adolescent↗
PubMed2004

Cataract surgery in patients with nanophthalmos: results and complications.

PURPOSE: To evaluate the results and complications of cataract surgery in patients with nanophthalmos. SETTING: University hospital practice. METHODS: The records of consecutive patients with nanophthalmos who had cataract surgery from 1978 through 2002 were reviewed for ocular diagnoses, corneal diameter, keratometry, axial length, retinal-choroidal-scleral thickness determined by echography, ocular surgeries, visual acuity, and complications. RESULTS: Eight patients (6 women, 2 men) with a mean age of 59 years were reviewed. Four patients were not previously diagnosed with nanophthalmos; increased retinal-choroidal-scleral thickness (mean 2.41 mm) confirmed the diagnosis. Twelve eyes had cataract extraction with posterior chamber intraocular lens (IOL) implantation, 11 by phacoemulsification and 1 by extracapsular cataract extraction, and 4 eyes had lamellar scleral resections. Additional surgeries included glaucoma laser treatment (8 eyes), cyclocryotherapy (2 eyes), trabeculectomy with scleral resection (1 eye), trabeculectomy combined with phacoemulsification (1 eye), and neodymium:YAG laser capsulotomy (4 eyes). No eye lost vision; however, complications included severe iritis, broken IOL haptic with vitreous loss, posterior capsule opacity, choroidal hemorrhage, phthisis, and aqueous misdirection. CONCLUSIONS: Results indicate that echography should be used to assess retinal-choroidal-scleral thickness in eyes that are hyperopic and at risk for narrow-angle glaucoma. Thickening may confirm the diagnosis of nanophthalmos and allow careful preoperative assessment and appropriate operative procedures in these high-risk eyes. With advances in cataract, glaucoma, and uveal effusion treatments, surgical results in patients with nanophthalmos are improving.

Adult↗
PubMed2006

Nanophthalmos: ultrasound biomicroscopy and Pentacam assessment of angle structures before and after cataract surgery.

We report a case of nanophthalmos with intractable secondary glaucoma. Bilateral cataract extraction with intraocular lens implantation was used as definitive treatment for the chronic angle-closure glaucoma. The changes in angle and ciliary body anatomy were well documented with preoperative and postoperative Pentacam assessment (Oculus Optikgeräte GmbH) and ultrasound biomicroscopy (Paradigm Medical Industries) images. We believe these are the first diagnostic and prognostic images of this kind in a nanophthalmic eye.

Anterior Eye Segment↗
PubMed2006

Critical period and minimum single oral dose of ochratoxin A for inducing developmental toxicity in pregnant Wistar rats.

Ochratoxin A (OTA), a potent in vivo teratogen, has been tested in various laboratory animal species. Present investigation was conducted to determine critical dose and critical time for the developmental toxicity of OTA in pregnant Wistar rats after single oral dose administration. OTA at different graded dose levels (2-4 mg/kg body weight) and at different gestation days (6-15), caused variable developmental defects in developing fetuses. OTA at 2.75 mg/kg body weight, dissolved in 0.1 M sodium bicarbonate (vehicle) and administered by oral intubation as a single dose on one of the gestational days 6-15, caused significant maternal toxicity in the dams and various gross, visceral and skeletal anomalies in the fetuses. The major gross malformations were external hydrocephaly, incomplete closure of skull and omphalocele. Internal hydrocephaly, microphthalmia, enlarged renal pelvis and renal hypoplasia were the main internal soft tissue anomalies. Major skeletal defects were developmental defects in skull bones, sternebrae, vertebrae and ribs. The gestational days 6 and 7 were found to be the most critical for the induction of teratogenicity in rats. Single oral dose of 2.75 mg/kg body weight OTA was found to be the minimum effective teratogenic dose in pregnant Wistar rats.

Abnormalities, Drug-Induced↗
PubMed2005

Defects in chicken neuroretina misexpressing the BMP antagonist Drm/Gremlin.

During eye development, bone morphogenetic proteins (BMPs) exert multiple actions on both early and late patterning and differentiation processes. However, the roles of BMP signaling in retinal differentiation are not well understood. To gain insight into a novel role of BMPs during retinal development, we proceeded to retrovirally directed misexpression of the BMP antagonist Drm/Gremlin in the chicken optic vesicle. This resulted in severe eye defects, characterized by microphthalmia, coloboma and the presence of dark streaks. The latter phenotype corresponds to localized perturbations of the stratified structure of the neuroretina. We show that these retinal disorganizations are characterized by a destruction of neuronal layers associated with axonal pathfinding defects, increased apoptosis and lost of N-cadherin expression. Moreover, whereas neuronal differentiation seems to proceed normally, Müller glial differentiation is impaired in Drm-induced disorganizations. These data suggest a possible role of BMP signaling in the laminar organization of the developing neuroretina.

Animals↗
PubMed2006

Long-range downstream enhancers are essential for Pax6 expression.

Pax6 is a developmental control gene with an essential role in development of the eye, brain and pancreas. Pax6, as many other developmental regulators, depends on a substantial number of cis-regulatory elements in addition to its promoters for correct spatiotemporal and quantitative expression. Here we report on our analysis of a set of mice transgenic for a modified yeast artificial chromosome carrying the human PAX6 locus. In this 420 kb YAC a tauGFP-IRES-Neomycin reporter cassette has been inserted into the PAX6 translational start site in exon 4. The YAC has been further engineered to insert LoxP sites flanking a 35 kb long, distant downstream regulatory region (DRR) containing previously described DNaseI hypersensitive sites, to allow direct comparison between the presence or absence of this region in the same genomic context. Five independent transgenic lines were obtained that vary in the extent of downstream PAX6 locus that has integrated. Analysis of transgenic embryos carrying full-length and truncated versions of the YAC indicates the location and putative function of several novel tissue-specific enhancers. Absence of these distal regulatory elements abolishes expression in specific tissues despite the presence of more proximal enhancers with overlapping specificity, strongly suggesting interaction between these control elements. Using plasmid-based reporter transgenic analysis we provide detailed characterization of one of these enhancers in isolation. Furthermore, we show that overexpression of a short PAX6 isoform derived from an internal promoter in a multicopy YAC transgenic line results in a microphthalmia phenotype. Finally, direct comparison of a single-copy line with the floxed DRR before and after Cre-mediated deletion demonstrates unequivocally the essential role of these long-range control elements for PAX6 expression.

Animals↗