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A microphthalmic strain of mice was used to study immunoresponse of the retinoblastoma protein. Comparing wild-type, heterozygote and homozygote microphthalmic eyes, we found an increasing labelling of phosphorylated retinoblastoma protein (pRb) in the retinal pigment epithelium. Additionally, microphthalmic eyes expressed pRb in the neuroepithelium. Especially rosettes were strongly labelled.
A study about the distribution of neuronal nitric oxide synthase (n-NOS) and inducible NOS (i-NOS) was performed in microphthalmic retinas at postnatal day (pd) 2 and pd 7. Neither n-NOS nor i-NOS immunoresponse could be detected at pd 2. At pd 7, i-NOS activity was revealed in the retinas of mi/mi littermates but not in those of heterozygotes or wild-type littermates. The expression of n-NOS corresponded to the postnatal retinal development. Retinal rosettes were strongly labelled.
It is well known that teeth do not erupt in microphthalmic (mi/mi) mice, a type of osteopetrotic mice, due to bone resorption failure. Therefore, we surmise that the masticatory function of these mice is different from that of normal mice. In this study, the differences to the properties of masseter muscle fibers were clarified morphologically and immunohistochemically in the mi/mi and normal mice. Morphological observations revealed that the muscle fibers in the mi/mi mice were smaller than those in normal mice at 9 weeks of age. However, no marked differences between mi/mi and normal mice at 2 and 4 weeks of age. Immunohistochemical observations showed myosin heavy chain (MHC) slow type fibers, which were usually seen at only early stages of development, in 4-week old mi/mi mice. There were also differences in isoform compositions between the mi/mi and normal mice. These results suggest that differences in masticatory function affect the properties of its muscle fibers.
Three patients with an oblique facial cleft are described. One patient displayed ring constriction, lymphoedema, distal pseudosyndactyly and an occipital encephalocele to which an amniotic band was attached at birth. Therefore, it was obvious that the oblique facial cleft was accompanied by an amnion rupture sequence. These signs were not apparent in the other patients. However, one of the patients demonstrated various anomalies, amongst which syndactyly on the right foot, scoliosis, microcephaly, microphthalmia and corneal opacity suggested that the patient may have been affected by the amnion rupture sequence, except for polydactyly on the left foot, cleft hand and vertebra plana.
PURPOSE: The increased incidence of sleep disorders among blind patients has been documented in the sleep medicine literature. Blind patients lack the normal regulatory control of retinal input over their circadian rhythms, which can lead to abnormalities in their sleep-wake cycles. Our study was conducted to determine the incidence of sleep disorders in children with anophthalmia or microphthalmia and to offer therapeutic alternatives. METHODS: A 13-question survey was distributed to families of children with anophthalmia, microphthalmia, or both identified through the Anophthalmia/Microphthalmia Registry in Philadelphia, Pennsylvania. The survey included questions regarding the children's medical and ocular histories and any sleep disorders they may have experienced. Questions regarding daily schedules, family history, and social history were also included. RESULTS: Surveys were returned from 13 children with bilateral anophthalmia or microphthalmia. Ten of 13 (77%) anophthalmic/microphthalmic children were reported to have frequent early-morning waking and extensive daytime sleeping. Specific medical and social problems did not appear to be associated with the development of these sleep disorders. Strict daily schedules were often helpful in entraining the children's sleep-wake cycles. CONCLUSION: Without the contribution of retinal input to help regulate circadian rhythms, most children with bilateral anophthalmia or microphthalmia will experience sleep disorders. These children may benefit from the introduction of strict daily schedules, medical therapy (melatonin), or both. An attempt should also be made to preserve any existing light perception.
Under normal conditions activated protein C is a natural anticoagulant that cleaves 2 activated coagulation factors, factor Va and factor VIIIa, thereby inhibiting the conversion of factor X to factor Xa and of prothrombin to thrombin. Additionally, activated protein C enhances tissue-plasminogen activator-mediated fibrinolysis by inhibition of plasminogen activator inhibitor-1. This results in an increase in circulatory plasminogen activator levels. Protein C deficiency, a genetic or acquired thrombophilic abnormality, has been demonstrated to predispose to episodes of potentially blinding and lethal thromboembolic events. Heterozygous-deficient subjects usually remain asymptomatic until adolescence or adulthood. In homozygous-deficient patients, protein C activity is usually less than 1% (reference range, 70%-140%), resulting in thromboembolism as early as in the neonatal period. The major clinical symptoms in affected newborn infants have been purpura fulminans, vitreous hemorrhage, and central nervous system thrombosis. The age of onset of the first symptoms has ranged from a few hours to 2 weeks after birth, usually after an uncomplicated full-term pregnancy and delivery. In contrast to the genetic form, acquired neonatal protein C deficiency occurs particularly in ill preterm babies. Typical complications of prematurity such as respiratory distress syndrome, necrotizing enterocolitis, and neonatal sepsis may also be present. In the medical literature, there are only a few reports of homozygous protein C deficiency in neonates. We present 2 cases of homozygous protein C deficiency with ocular and extraocular manifestation.
For a long time the biology of mast cells has remained an enigma. During the past few decades, molecular research has filled many of the gaps in our understanding of this multifunctional cell type. Several concepts are now established about the origin and development of mast cells. However, the mechanisms leading to autonomous proliferation of mast cells in patients with indolent or aggressive mastocytosis still require further investigation. This article focuses on the recent advances in the field of mast cell development and abnormal mast cell proliferation, and reviews data from the most significant mouse models, which have provided the basis for many of these new insights.
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A very rare abnormality is reported of congenital absence of the right half of the nose in combination with microphthalmia, coloboma, epiphora and median cleft of the alveolus.
PURPOSE: To report the treatment of exudative retinal detachment in a patient with nanophthalmos. METHODS: A 46-year-old man with bilateral nanophthalmos suffered from acute angle-closure glaucoma in his left eye. The first day after a peripheral iridectomy an exudative retinal detachment was observed. Two months later a partial thickness sclerectomy with a central sclerostomy, covered by a thin film of absorbable gelatine, was performed in each quadrant of the left eye. RESULTS: The retinal detachment gradually resolved and after eight months the retina was completely reattached. Vision, which had been limited to hand movements, improved to 6/18 with correction. CONCLUSION: Scleral resections are effective in the treatment of nanophthalmic retinal detachment. The use of absorbable gelatine film to cover the sclerectomized area may prevent regeneration of scleral tissue and recurrence of the exudative retinal detachment.
PURPOSE: To report the occurrence of postoperative glaucoma and to evaluate risk factors. METHODS: Children born in four of the western counties of Sweden who were diagnosed with congenital cataracts formed a cohort (n=137). The following parameters were evaluated: age at cataract surgery; type of surgery; visual outcome; postoperative IOP; optic disc abnormalities; date of onset of the complication; number of reoperations, including treatment for secondary cataract; presence of systemic anomalies; microphthalmus; and eye-related anomalies. RESULTS: A diagnosis of glaucoma was recorded for 12% of the eyes. The mean follow-up time was 9.6 years. There is a relationship between surgery before the age of 10 days and development of glaucoma. Microphthalmus is an important risk factor as well. CONCLUSIONS: Despite modern surgical techniques the incidence of aphakic glaucoma is 10% or higher. No time-dependent increase in the incidence of late-onset glaucoma between the 1980s and the 1990s could be proven.
In a seventy-five-year old man an optic nerve coloboma with generalised retinal degeneration associated with a cystic microphthalmia of the other eye is described. The MR imaging revealed the existence of a left microphthalmic eye with a lower lid cyst. From the other eye an optic nerve coloboma with a cystic ectasia of the coloboma area freely open to the vitreous cavity was apparent. The ERG recorded from this eye was extinguished.
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Isolated human microphthalmia/anophthalmia, a cause of congenital blindness, is a clinically and genetically heterogeneous developmental disorder characterized by a small eye and other ocular abnormalities. Three microphthalmia/anophthalmia loci have been identified, and two others have been inferred by the co-segregation of translocations with the phenotype. We previously found that mice with ocular retardation (the or-J allele), a microphthalmia phenotype, have a null mutation in the retinal homeobox gene Chx10 (refs 7,8). We report here the mapping of a human microphthalmia locus on chromosome 14q24.3, the cloning of CHX10 at this locus and the identification of recessive CHX10 mutations in two families with non-syndromic microphthalmia (MIM 251600), cataracts and severe abnormalities of the iris. In affected individuals, a highly conserved arginine residue in the DNA-recognition helix of the homeodomain is replaced by glutamine or proline (R200Q and R200P, respectively). Identification of the CHX10 consensus DNA-binding sequence (TAATTAGC) allowed us to demonstrate that both mutations severely disrupt CHX10 function. Human CHX10 is expressed in progenitor cells of the developing neuroretina and in the inner nuclear layer of the mature retina. The strong conservation in vertebrates of the CHX10 sequence, pattern of expression and loss-of-function phenotypes demonstrates the evolutionary importance of the genetic network through which this gene regulates eye development.
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