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At least 577 records · Page 32Linked to original sources
PubMed1996

Immunohistochemical studies of glycosaminoglycans in nanophthalmic sclera.

BACKGROUND: It has been observed that there may be some connection between scleral collagen changes, glycosaminoglycan (GAG) changes and nanophthalmic uveal effusion. In a previous paper we reported increased dermatan sulfate (DS) and chondroitin sulfate (CS) contents in nanophthalmos sclera using biochemical analysis. In the present work we used immunohistochemical methods to assess the GAG changes in nanophthalmos sclera. METHODS: Scleral specimens from three nanophthalmic patients and five controls were processed to immunostaining with peroxidase-antiperoxidase (PAP) methods. Monoclonal antibodies for chondroitin (Ch), chondroitin-4-sulfate (C4S), chondroitin-6-sulfate (C6S), DS and keratan sulfate (KS) were used. The specimens were observed under a light microscope. RESULTS: Nanophthalmos scleral samples exhibited strong KS staining compared with the control specimens. Both the nanophthalmos and the control samples were stained with anti-Ch, anti-C4S, anti-C6S and anti-DS antibodies to the same intensity. CONCLUSION: Our results suggest that an increased or abnormal distribution of KS may contribute to abnormalities in collagen fibers.

Adolescent↗
PubMedDate not supplied

Autosomal dominant congenital cataract and microphthalmia associated with a familial t(2;16) translocation.

We describe a family in which autosomal dominant congenital cataract and microphthalmia were segregating together with a reciprocal translocation t(2;16) (p22.3;p13.3) through three generations. This family included four individuals with balanced translocations, three with partial trisomy 2p derived from this translocation, and two with a normal karyotype. All of the subjects with balanced and unbalanced translocations had congenital cataract and microphthalmia, whereas the two individuals with normal karyotypes did not show any ocular anomalies. These observations suggest that the altered function of a gene that lies on the 16p13.3 band and that has an important role in the development of the eye is responsible for this disorder.

Abnormalities, Multiple↗
PubMedDate not supplied

Treatment of glaucoma in young nanophthalmic patients.

PURPOSE: To evaluate the criteria of diagnosis and management of secondary glaucoma in young nanophthalmic patients. METHODS: Considering the anatomic features and clinical characteristics, 22 eyes of 11 patients were identified as bilateral nanophthalmos. Intraocular pressures (IOP) were checked with Goldmann applanation or Keeler pulse-air 2000 tonometer, and Nd-Yag laser was used for iridotomies. Prophylactic V-shaped unsutured sclerectomies over the pars plana were combined with trabeculectomy, and Mitomycin C (MMC) in 0.2 mg/ml concentration was applied. RESULTS: Among 22 eyes of bilateral nanophthalmic patients 8 eyes had secondary angle-closure glaucoma. Laser iridotomies were performed in 6 eyes. Laser iridotomy and supplemental medical therapy were sufficient in 4 out of 6 eyes. Mean IOP dropped from 26.4 to 14.5 mmHg in these patients. Due to continuous increase of IOP in the other patients, they underwent trabeculectomy with V-shaped sclerostomy and intraoperative MMC application. Mean IOP dropped from 39.3 mmHg to 19.3 mmHg. Postoperative uveal effusion on other major complications were not observed. Mean age of these patients was 14.6 years during treatment. CONCLUSION: Management of glaucoma in nanophthalmus is complicated. Initial treatment is medical. If it is insufficient, laser iridotomies and V-shaped sclerostomies with filtration surgery can be performed at any age.

Adolescent↗
PubMed1992

Morphology of a dicephalic cat.

A detailed anatomical study of a dicephalic iniodymic monosomic cat in conjunction with the morphogenetical implications of the observed anomalies is presented. The animal exhibited two heads joined at the level of an anomalous medial exoccipital bone. Two brains and two foramina magna were present. The vertebral column was single but the cranial cervical vertebrae (C2 to C5) had doubled bodies. Cervical rachischisis with myeloschisis were associated defects. Two nasopharyngeal and oropharyngeal cavities converged caudally into a single laryngopharynx. The esophagus, larynx and trachea were single. Duplication of the tongue and hyoid apparatus was present. Palatoschisis affected both oral cavities. Hypoplasia of the anatomical structures in the medial aspects of both heads was observed. Microphthalmia was also observed in both medial eyes. Comparative aspects of the morphology, causative agents, and mechanisms and anomalous morphogenesis of anterior duplications are reviewed and discussed.

Abnormalities, Multiple↗
PubMed1976

Surface morphology of lens fibers from eyes of normal and microphthalmic (Browman) rats.

The surface features of cortical fibers from lenses of normal adult rats and microphthalmic rats of the Browman strain have been studied by scanning electron microscopy. In the normal lenses, superficial cortical fibers follow a straight course from inner to outer pole whereas the deeper cortical fibers, while straight near the poles, pursue an undulating or zig-zag course at and near the equator. Almost all of the fibers are hexagonal in cross section and all fibers throughout their entire length are bound by interdigitating processes at each corner of the hexagon to corners of two adjacent fibers. Some fibers are also affixed by a single row of ball and socket junctions located on their broad outer and inner surfaces. Lens fibers from Browman rats display both minor and major abnormalities. These included segmentation, formation of incisures and lateral protrusions, corrugation and villous-like alteration of the broad fiber surface and development of parallel ridges of broad surfaces in a basket-weave pattern.

Animals↗
PubMed1985

Ultrastructural development of the dorsal lateral geniculate nucleus of genetically microphthalmic mice.

The ultrastructure of the dorsal lateral geniculate nucleus (dLGN) of microphthalmic mice is described in affected white homozygotes (mi/mi) and their apparently normal grey littermates. In the dLGN of mi/mi animals populations of apparently normal axon terminals were observed, including some with flattened synaptic vesicles and other small terminals with round vesicles and dark mitochondria (RSD), possibly of cortico-thalamic origin, just as in normal mice. However, no typical large retinal endings with round vesicles and pale mitochondria (RLP) are visible. Instead they appear to be replaced by other large boutons with round vesicles and dark mitochondria (RLD). Eye enucleation does not cause degeneration of these RLD terminals. In apparently normal grey littermates RLP terminals are present and they degenerate when an eye is enucleated. But RLD endings are also found in these animals, and never degenerate after enucleation. The origin of the RLD terminals is unclear but seems not to be cortical. These findings are compared with those of Cullen and Kaiserman-Abramof (1976) in a different strain (ZRDCT-An) of anophthalmic mouse in which they found large replacement terminals similar to our RLD boutons.

Animals↗
PubMed1985

Distribution of the tecto-thalamic projection neurons in the hereditary microphthalmic rat.

Tecto-thalamic projections in the hereditary bilaterally microphthalmic rat were studied by means of WGA-HRP injection into the dorsal lateral geniculate nucleus (LGNd) and the lateroposterior thalamic nucleus (LP). Histological study in the mutant rats showed that whereas LGNd and superficial layers of the superior colliculus (SC) suffered from a remarkable reduction in size, LP had no histological changes as compared to the normal animals. Unilateral injection of the tracer into the microphthalmic LGNd showed that WGA-HRP positive neurons were present mostly in the ipsilateral str. griseum superficiale (SGS) of the SC. However, the number of labeled SGS neurons of the microphthalmic animals was about 3% of the normal. Although cell bodies of the normal tecto-LGNd neurons in the SGS were spindle-form in shape and issued one or two proximal dendrites from each pole, the microphthalmic tecto-LGNd neurons showed an irregular contour and their dendrites were not so intensively labeled. Unilateral injections of WGA-HRP into the LP revealed that the tecto-LP neurons were mainly distributed in the ipsilateral str. opticum of the colliculus (SO) in both normal and microphthalmic animals. However, the number of labeled SO cells in the microphthalmic rat was about one-half of the normal. Furthermore, the size of labeled tecto-LP neurons was smaller than that of the normal ones, and they showed irregular round to oval cell bodies with equivocally labeled dendrites, in contrast to the normal tecto-LP neurons with polygonal cell bodies extending three or more dendrites in a radial fashion. These results indicate that there exist the tecto-LGNd and -LP projection neurons in the microphthalmic rat and that their laminally segregated projection is fundamentally preserved. However, the number of the tecto-thalamic projection neurons, especially of the tecto-LGNd cells, was markedly diminished in the mutant tectum compared to normals.

Animals↗
PubMed1995

Biochemical studies of glycosaminoglycans in nanophthalmic sclera.

BACKGROUND: Since Brockhurst reported the connection between uveal effusion in nanophthalmic eyes and their scleral alterations and treated them with vortex vein decompression or sclerectomy, many observers have found abnormal accumulation of glycosaminoglycans (GAGs) in nanophthalmic sclera. These GAG abnormalities were thought to effect the collagen changes, though it was not clear which GAGs were changed. METHODS: GAGs were isolated and their contents were determined in scleral specimens from three nanophthalmic patients and five age-matched controls, using electrophoresis and the cetylpyridinium method. RESULTS: Hyaluronic acid, dermatan sulfate and chondroitin sulfate were the major GAGs in both nanophthalmic and control samples. Nanophthalmic sclera showed 2.4-fold, 10-fold and 5.5-fold increases in hyaluronic acid, dermatan sulfate and chondroitin sulfate, respectively, compared with the controls. CONCLUSION: The results suggest that increased levels of GAGs, particularly of dermatan sulfate and chondroitin sulfate may contribute to the abnormalities of collagen fibrillogenesis and be closely involved with the pathogenesis of nanophthalmos.

Adult↗
PubMed1975

A 46,XX,10Q+ chromosome constitution in a girl. Partial long arm duplication or insertional translocation?

A girl with slight psychomotor retardation, microphthalmia, and colobomata of the left eye, a hypotrophy of the right arm and a surnumerary digit on the right hand is described. The routine chromosome analysis and a G-banding analysis revealed an elongated long arm of chromosome 10. An extra light and dark band was present proximally. Both parents had normal chromosomes. While the visual comparison of the abnormal with the normal chromosome 10, did not enable the extra bands of the normal bands q21 and q22 to be distinguished. However, measurements of length, surface area, and relative reflection of the different light and dark bands of the long arm on tracings or directly on the normal and abnormal chromosomes, enabled us to precisely locate the extra bands and to determine that the abnormal chromosome was a result of an insertional translocation. The value of such measurements is discussed.

Arm↗
PubMed1984

Reproductive outcomes of paracentric inversion carriers: report of a liveborn dicentric recombinant and literature review.

An abnormal infant had a dicentric chromosome 14 with an inverted tandem duplication [46,XY,inv dup(14) (pter----q32.3::q24.2----pter)], thus making him trisomic for the proximal two-thirds of chromosome 14. This abnormality was derived from a maternal paracentric inversion in chromosome 14 [46,XX,inv(14)(q24.2q32.3)]. To our knowledge, this is the first report of a liveborn infant carrying a stable, dicentric product of crossing over within a paracentric inversion loop. A review of the reproductive outcomes of paracentric inversion carriers in the literature suggests that they are at some risk for pregnancy wastage. The risk for liveborn recombinants is small but such births have occurred, at least to female carriers.

Abnormalities, Multiple↗
PubMed1981

Development of coloboma (Cm/+), a mutation with anterior lens adhesion.

A semidominant mutation in the laboratory mouse, Coloboma (Cm), is described. Coloboma is located on Chromosome 2, as is the similar mutation Dickie's small eye (Dey). Coloboma has a moderately reduced expressivity. The anterior chamber is usually present in Cm/+. Both Cm and Dey show delayed detachment of the lens vesicle and microphthalmia, and homozygotes of both apparently die early in pregnancy.

Animals↗
PubMed1993

Defects of neuronal migration and the pathogenesis of cortical malformations are associated with Small eye (Sey) in the mouse, a point mutation at the Pax-6-locus.

The mouse Small eye (Sey) locus is situated on chromosome 2. Molecular analyses have shown that SeyNeu represents a point mutation leading to a splice site error and loss of the functional gene product. The Sey locus has been shown to be identical with the paired box (Pax)-6 gene, which contains paired-like and homoeobox domains and is a developmental control gene. Pax-6 expression occurs in many parts of the central nervous system during embryogenesis. Therefore, we may expect the Sey mutation to result in abnormal development of the central nervous system. The present study shows that Pax-6 mutation has a bimodal effect upon neurogenesis in mouse: it causes a delay of premigratory neurons in a stage-, region-, and gene-dose-dependent manner. Additionally, Sey mutation impairs axonal growth and differentiation. Neurons of the cortical plate cease differentiation on approximately day 16 of gestation and appear to have increased cohesion: their cytoplasm is swollen and vacuolated. These changes coincide both with reduced formation of axons and with the onset of vacuolar degeneration in existing axons, glial cells and radial glial fibers. Consequently, there is an impairment of the peripheral migration of putative neurons so that the neonatal lesion pattern of the neocortical roof becomes dominated by a broad spectrum of neuronal migration disorders.

Animals↗