Macula halo syndrome without systemic abnormalities.
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Color Perception Tests↗
Biomedical subjects
T Shiono
Publications and source records attributed to T Shiono.
Abnormal sclerocytes in nanophthalmos.
Scleral tissue from a nanophthalmic patient was examined morphologically and by a tissue culture method. Collagen in the unusually thickened scleral tissue was arranged in irregularly interlacing bundles. Results of tissue culture studies showed sclerocytes that seemed to secrete many granules that stained positively with Alcian blue and periodic acid-Schiff (PAS). No granules were seen in cells of scleral tissue cultured from two control eyes. These findings may be the result of the modified glycosaminoglycan metabolism, which in turn contributes to the abnormal packing of collagen bundles and thickening of sclera in nanophthalmos.
Adult↗
Vitreous, retinal and subretinal hemorrhages associated with von Willebrand's syndrome.
Two patients with von Willebrand's syndrome had intraocular hemorrhages without trauma or neovascularization. A 13-year-old Japanese girl complained of sudden spotted vision in her left eye. Vitreous, peripapillary retinal, and subretinal hemorrhages were seen by ophthalmoscopy in the affected eye. In addition, a 19-year-old Japanese man had repeated vitreous hemorrhage and epistaxis. Also noted was gyrate atrophy of the choroid and retina. Analysis of the coagulation-fibrinolysis system revealed decreased activities of Factor VIII and von Willebrand's factor in both patients. The amount of von Willebrand's factor antigen also was decreased. These results suggested that the patients had von Willebrand's syndrome. The bleeding tendency in the disorder appeared to be responsible for the pathogenesis of the intraocular hemorrhages seen in these patients.
Adolescent↗
Point mutations of rhodopsin gene found in Japanese families with autosomal dominant retinitis pigmentosa (ADRP).
The mutations of codon 17, 23, 58, and 347 of rhodopsin gene were investigated in 24 unrelated Japanese families including 33 patients with autosomal dominant retinitis pigmentosa (ADRP). A patient with codon 17 mutation (Thr-17-Met, ACG-->ATG) and a family including 4 patients with codon 347 mutation (Pro-347-Leu, CCG-->CTG) were detected among them. Their clinical findings were extremely different between the two mutations. The former showed type 2 and the latter showed type 1 ADRP. No mutation of codon 23 and 58 was detected in any families so far analyzed in the present study. Clinical findings associated with the mutation in codon 17 and 347 of the rhodopsin gene show an existence of allelic heterogeneity.
Adolescent↗
ECG changes under hyperkalemia with nephrectomy in the rat.
Electrolyte abnormalities have become an increasingly important cause of arrhythmias. Although the electrocardiographic (ECG) changes under hyperkalemia in the rat are poorly understood, it is conceivable that excess plasma potassium may also alter the cardiac excitations in the rat. Further, effects of hyperkalemia on ECG in the rat may differ from other species that have ST-segment and longer QT intervals in ECG. The present study was designed to determine the diagnostic criteria for ECG manifestations to various levels of plasma potassium concentration. For this purpose, hyperkalemia was induced by nephrectomy with and without infusions. Because it was difficult to produce various levels of plasma potassium concentration by only nephrectomy, we used two kinds of infusions to obtain especially moderate levels of nephrectomy-induced hyperkalemia. ECGs were recorded 24, 36, and 48 hours after nephrectomy. Plasma potassium concentration and number of abnormal ECGs were increased time-dependently. Increased T wave amplitude was present with mild hyperkalemia. The typical T wave change observed with so-called sinoventricular conduction levels of potassium concentration in species with long QT intervals did not occur in the rat. PR interval and QRS duration became slightly shorter within moderate hyperkalemia. P wave disappeared in most rats at potassium levels above 8.0 mEq/l. In advanced hyperkalemia (plasma potassium concentration above 7.5 mEq/l), conduction in all parts of the heart was suppressed. Moreover, sinoventricular conduction appeared. Thus, the diagnostic criteria for ECG manifestations to various levels of plasma potassium concentration in the rat were demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
[A case of chronic progressive external ophthalmoplegia with Oguchi's disease].
A 52-year-old case of chronic external ophthalmoplegia accompanied by Oguchi's disease was reported. The patient noticed night blindness and deafness since childhood. Later he developed ocular movement limitation to all directions by the age of 40. He had 20/20 corrected visual acuity and normal anterior segment, as well as normal color vision. Goldmann's perimetry showed generalized constriction of the peripheral field. Golden tapetal reflex without dark adaptation disappeared after 4 hours of dark adaptation, i.e. Mizuo-Nakamura's phenomenon was recognized. Recovery of diminished a and b wave electroretinogram to the subnormal range was also observed after 4 hours of dark adaptation. Rod-cone interaction test revealed a monophasic adaptation, and no suppression to the cones from the rods was observed. This finding was also compatible with Oguchi's disease. ECG revealed incomplete atrio-ventricular as well as right bundle branch blocks. Neurological examination findings were entirely normal other than slight enhancement of deep tendon reflexes in the lower extremities and mixed typed difficulty of hearing. Muscle biopsy of the right medial rectus muscle revealed ragged-red fiber, suggesting mitochondrial abnormalities. Never the less the quadriceps femoris muscle biopsy specimen showed normal histological findings. This is the first case report of progressive external ophthalmoplegia associated with Oguchi's disease. Mitochondrial abnormality was confirmed only in the external ocular muscle. This case may be a variant of Kearns-Sayre syndrome.
Humans↗
[An epidemiogenetic study of typical retinitis pigmentosa in Japan--a preliminary report of nationwide, multicenter study].
We performed a nationwide, multicenter study of typical retinitis pigmentosa with reference to the inheritance patterns of the disease. A total of 253 probands were registered during two months of 1989, and an analysis of the parental consanguinity of 182 probands with the method of inbreeding coefficient enabled us to estimate the relative prevalence of genetic types; autosomal recessive trait: 47.6%; autosomal dominant trait: 17.3%; sporadic cases: 34.6%. A comparison of the results with previous studies has indicated a decrease in the prevalence of the autosomal recessive trait and an increase in the sporadic cases, as would be expected from the decrease in consanguineous marriages and offsprings in the past few decades in Japan. X-linked retinitis pigmentosa was rarely identified, but precise evaluation of its frequency needs further investigation.
Adolescent↗
[Molecular biological study of the rhodopsin gene in Japanese patients with autosomal dominant retinitis pigmentosa].
The author analyzed codon 347 of the rhodopsin gene using PCR (polymerase chain reaction) amplification and restriction enzymes in 19 unrelated Japanese families including 28 patients with autosomal dominant retinitis pigmentosa (ADRP). An allele of codon 347 mutation was found in a family (father and daughter). Sequence analysis shows that the mutation is from CCG to CTG. This mutation appears to be the cause of one form of ADRP, since it was also found in Japanese cases of ADRP which have a different racial background from families reported by Dryja et al.
Codon↗
Nonsense-codon mutations of the ornithine aminotransferase gene with decreased levels of mutant mRNA in gyrate atrophy.
A generalized deficiency of the mitochondrial matrix enzyme ornithine aminotransferase (OAT) is the inborn error in gyrate atrophy (GA), an autosomal recessive degenerative disease of the retina and choroid of the eye. Mutations in the OAT gene show a high degree of molecular heterogeneity in GA, reflecting the genetic heterogeneity in this disease. Using the combined techniques of PCR, denaturing gradient gel electrophoresis, and direct sequencing, we have identified three nonsense-codon mutations and one nonsense codon-generating mutation of the OAT gene in GA pedigrees. Three of them are single-base substitutions, and one is a 2-bp deletion resulting in a reading frameshift. A nonsense codon created at position 79 (TGA) by a frameshift and nonsense mutations at codons 209 (TAT----TAA) and 299 (TAC----TAG) result in abnormally low levels of OAT mRNA in the patient's skin fibroblasts. A nonsense mutation at codon 426 (CGA----TGA) in the last exon, however, has little effect on the mRNA level. Thus, the mRNA level can be reduced by nonsense-codon mutations, but the position of the mutation may be important, with earlier premature-translation termination having a greater effect than a later mutation.
Adult↗
Clinical features of Japanese family with autosomal dominant retinitis pigmentosa caused by point mutation in codon 347 of rhodopsin gene.
Four members in a Japanese family had autosomal dominant retinitis pigmentosa caused by a single point mutation in codon 347 of the rhodopsin gene. The youngest, an 11-year-old girl, had an abnormal electroretinographic response, although her fundus appeared normal. The other affected family members noticed night blindness in the second decade. Their fundi showed diffuse pigmentation with concentric visual field loss, and there was no recordable electroretinographic response. Cataract developed in the fourth decade in the older patients. Good visual acuity was retained however, even in the fifth decade, after cataract extraction. These clinical features were similar to those of American patients (European family origin) with the same mutation of the rhodopsin gene reported previously.
Adult↗
A mutation of mitochondrial DNA in Japanese families with Leber's hereditary optic neuropathy.
Leber's hereditary optic neuropathy (LHON) is a maternally inherited disease characterized by optic nerve degeneration associated with severe bilateral visual loss in young men and occasionally in women. A mitochondrial DNA (mtDNA) replacement mutation in LHON patient, G to A transition at nucleotide position (nt) 11778 converting the 340th arginine to histidine in the NADH dehydrogenase subunit 4, was detected as SfaNI site polymorphism (Wallace et al., Science, 242: 1427-1430, 1988). To evaluate if the SfaNI site loss can be used to diagnose LHON patients, mtDNAs from peripheral blood of six affected males including five probands from five unrelated Japanese families with LHON, a pair of parents and a normal sister of one of the probands and 4 control persons were analyzed using PCR amplification method. The mutation of leukocyte mtDNA at nt 11778 was identified in all of the affected patients, the normal mother and the sister examined, while the father who is normal and 4 control persons did not show the change. These findings support that the mutation at nt 11778 is also associated with LHON in the Japanese and the test of the SfaNI site loss described here is useful for confirming the clinical diagnosis of LHON patients with the mutation at nt 11778.
Asian People↗
Macular choroidal occlusion in dysplasminogenemia.
The authors describe a family with dysplasminogenemia. This diagnosis was based on a lowered ratio of functional plasminogen activity to immunologic plasminogen antigen level, associated with fundus abnormalities. The proband is a 31-year-old woman with Graves disease who had choroidal occlusive lesions of the macula in both eyes. The results of the laboratory examination indicated that the patient was a homozygote for dysplasminogenemia. Similar examinations of the patient's parents and siblings showed their plasminogen levels to be 50% below normal. The thrombotic tendency in this disorder appeared to be responsible for the pathogenesis of the macular choroidal occlusion.
Adult↗
Decrease of opsin content in the developing rat photoreceptor cells by systemic administration of L-glutamate.
L-Glutamate, a putative photoreceptor cell neurotransmitter, causes thinning of the inner layers of the retina and has been used for preparing biologically fractionated photoreceptor cells. However, it is possible that absence of the inner retinal layers may affect the remaining retina, and/or glutamate may directly affect photoreceptor cells. We evaluated quantitatively the effects of L-glutamate on the developing photoreceptor cells by measuring the rod photoreceptor cell-specific protein, opsin. We purified rat rhodopsin and used it as the standard for measuring opsin content of rat retinas with competitive enzyme-linked immunosorbent assay. Various concentrations of glutamate were injected into 7-day-old rats, and the effects of the amino acid concentration on opsin expression were determined on postnatal day 14. Inner layers of the retina degenerated when 10 microliters or 15 microliters of 2.4 M glutamate/gram body weight was administered subcutaneously. Opsin content of these glutamate-treated retinas decreased significantly compared with control retinas. We administered glutamate to rats at various stages of development and determined the effects by light microscopy on postnatal day 14. The administration of glutamate resulted in no degeneration of the inner retina if injected on postnatal day 1 or 2, degeneration of the inner retina between day 3 to 7, and again, no degeneration after postnatal day 13. Opsin content decreased significantly when glutamate was administered between postnatal day 1 to 7, but not after day 13, the day the blood-retinal barrier seems to reach maturity. Our findings indicate that systemic administration of L-glutamate affects the expression of opsin in the developing rod photoreceptor cells.
Animals↗
Analysis of rhodopsin gene in patients with retinitis pigmentosa using allele-specific polymerase chain reaction.
Point mutations within the rhodopsin gene have been found recently in some patients with autosomal dominant retinitis pigmentosa (ADRP). Currently, four types of point mutations at codons 23, 58 and 347 have been identified. The purposes of this study were to establish simple methods for screening patients with retinitis pigmentosa (RP) to detect these point mutations, and to apply these methods to determine if these mutations are found in Japanese patients with RP. Utilizing the polymerase chain reaction (PCR), a one-step method was developed to detect point mutations at codon 23. This method was then applied to screen genomic DNAs from 30 patients with various types of RP, including ADRP, autosomal recessive RP, simplex RP, Leber's congenital amaurosis or Usher's syndrome. Subsequently, point mutations at codons 58 and 347 were detected by restriction enzyme digestion (Dde I or Msp I) of exons 1 and 5 amplified by PCR. To date, no mutations have been found in codons 23 and 58 in Japanese patients. By using the allele-specific PCR, however, two patients from one pedigree of ADRP were confirmed to have a C-to-T transition at the second nucleotide of codon 347, which results in the substitution of leucine for proline. Our findings indicated the availability of this simple method for detecting these point mutations.
Alleles↗
Molecular basis of ornithine aminotransferase defect in gyrate atrophy.
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Amino Acid Sequence↗
Presumed drusen of optic nerve head in siblings with Usher syndrome.
Two siblings with Usher syndrome had optic disc mulberry tumors that were photographically documented over a 5-year period. During this period, growth of these tumors was demonstrated. These lesions were reported histologically to be drusen. The existence of presumed optic disc drusen in siblings with Usher syndrome may be related to similar pathogenetic mechanisms rather than genetic implications.
Child↗
[MR imaging and disorders in orthopedics].
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Humans↗
[A long-term follow-up of a patient with DIDMOAD (Wolfram) syndrome].
A 19-year-old Japanese woman developed diabetes mellitus, diabetes insipidus and optic atrophy. Other abnormal ocular findings included color blindness, elevated dark adaptation threshold and constriction of visual fields. Diabetic retinopathy, which is considered to be rare in this syndrome, also was found in the fundi of this patient. During the nine-year follow-up period, diabetic retinopathy deteriorated despite treatment by photocoagulation and vitrectomy, suggesting the importance of ophthalmological examinations in patients with DIDMOAD syndrome.
Adult↗