[Interaction between retino-tectal and cortico-tectal inputs in the cat's superior colliculus].
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Animals↗
Biomedical subjects
M Tamai
Publications and source records attributed to M Tamai.
Interaction between cortico-tectal and retino-tectal inputs as revealed by analysis of field potentials of the cat's superior colliculus.
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Animals↗
[An experimental study on temporal lobe epilepsy. The functional relationship between limbic system and brain stem structures].
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Animals↗
mRNA expression of proto-oncogenes and platelet-derived growth factor in proliferative vitreoretinal diseases.
PURPOSE: To detect the expression of mRNA of protooncogenes ets-1, c-jun, c-fos, and platelet-derived growth factor (PDGF) in proliferative membranes of patients with proliferative diabetic retinopathy (PDR) and proliferative vitreoretinopathy (PVR). METHODS: cDNA was synthesized from mRNA of proliferative membranes from patients with PDR, PVR, premacular fibrosis (PMF), acute retinal necrosis (ARN), and age-related macular degeneration (ARMD). Ets-1, c-jun, c-fos, PDGF-A, and PDGF-B cDNA were amplified using reverse transcriptase-polymerase chain reaction (PCR). RESULTS: Proto-oncogene mRNA was highly expressed in membranes from patients with severe PDR, grade D PVR. PDGF mRNA was expressed in almost all samples. CONCLUSIONS: Our results suggest that not only PDGF mRNA was expressed in the membranes of patients with PDR and PVR, but proto-oncogenes ets-1, c-jun, and c-fos mRNA were also expressed.
DNA Probes↗
Molecular genetic analysis of ABCR gene in Japanese dry form age-related macular degeneration.
PURPOSE: To explore whether the mutation in the retina-specific ATP-binding cassette transporter (ABCR) gene, the Stargardt's disease gene, contributes to the prevalence of the dry form of age-related macular degeneration (dry AMD) in Japanese unrelated patients. METHODS: Twenty-five Japanese unrelated patients with dry AMD who were diagnosed by fluorescein angiography and indocyanine green angiography were chosen as the dry AMD group. None of these cases had apparent choroidal neovascularization. To detect the mutations in the ABCR gene, genomic DNA was extracted from leukocytes of peripheral blood, and 26 exons of the ABCR gene were amplified by polymerase chain reaction (PCR). All the PCR products were then directly sequenced. When a mutation was detected, the occurrence of a mutation was compared between these AMD patients and the control group. RESULTS: After direct sequencing, a point mutation in exon 29 was found in one of the 25 dry AMD patients. In addition, a polymorphism in exon 45 was found in two other patients, and three sequence variations in exon 23 were detected in all patients. The incidence in AMD patients in whom a mutation in exon 29 (4%) was detected was less than that in controls (5%). Screening of the intron-exon boundaries also led to the identification of intronic mutation in intron 33. CONCLUSION: In this study we found no relationship between allelic variation in the ABCR gene and the prevalence of dry AMD in Japanese unrelated patients.
ATP-Binding Cassette Transporters↗
Quantitative analysis of interleukin-6 in vitreous from patients with proliferative vitreoretinal diseases.
PURPOSE: To explore immunological mechanisms in the pathogenesis of proliferative vitreoretinal diseases, we measured the concentration of interleukin-6 in the vitreous body and serum from patients with proliferative diabetic retinopathy (PDR), proliferative vitreoretinopathy (PVR), and premacular fibrosis. To evaluate immunological etiology, interleukin-6 levels in each disease were compared with disease severity. METHODS: Clinical samples were obtained at the beginning of pars plana vitrectomy from 30 eyes of 26 patients with PDR, 12 eyes of 12 patients with PVR, and 10 eyes of 10 patients with premacular fibrosis. Interleukin-6 was quantitated with an enzyme-linked immunosorbent assay. RESULTS: The levels of detectable interleukin-6 in the vitreous specimens ranged from 22.8 to 666.4 pg/mL in the PDR patients and from 28.2 to 416.3 pg/mL in the PVR patients. No interleukin-6 was detected in the vitreous specimens from patients with premacular fibrosis or in any serum samples from patients. Interleukin-6 levels of vitreous specimens from PDR patients were higher than those from PVR patients (P <.02, Mann-Whitney U-test). There was no correlation between clinical severity and interleukin-6 levels in vitreous specimens from either PDR or PVR patients. CONCLUSION: Our results indicated that cell-mediated immunity is involved in the pathogenesis of proliferative vitreoretinal diseases.
Adolescent↗
Adult-onset foveomacular vitelliform dystrophy with retinal folds.
BACKGROUND: Adult-onset foveomacular vitelliform dystrophy is characterized by a solitary, oval, slightly elevated, yellowish subretinal lesion of the fovea. We examined a patient with adult-onset foveomacular vitelliform dystrophy with stellate retinal folds by optical coherence tomography and scanning laser ophthalomoscopy. CASE: A 58-year-old Japanese woman with a complaint of decreased vision in her right eye was diagnosed as having adult-onset foveomacular vitelliform dystrophy. OBSERVATIONS: Ophthalmoscopic examination revealed a yellowish lesion of one-third disc diameter in size at the fovea in the right eye. Fluorescein angiography demonstrated an irregular block of choroidal fluorescence corresponding to the yellowish lesion, which was surrounded by stellate retinal folds. Optical coherence tomography images showed a steep elevation of the retinal pigment epithelium (RPE) as a focally protruded reflective band over an optically clear space. Scanning laser ophthalmoscopy provided morphologic enhancement in the specifically affected layers of the macula. Using an argon green laser, band-shaped bright reflexes were seen in the right fovea. The helium-neon laser revealed a bright patch corresponding to the yellowish lesion over the fovea, which was surrounded by stellate retinal folds. The diode laser revealed a bright patch corresponding to the yellowish lesion. CONCLUSION: The stellate retinal folds of this patient were considered to be caused by the steep elevation of the RPE with an extracellular accumulation of the vitelliform deposits.
Electroretinography↗
Multicenter genetic study of retinitis pigmentosa in Japan: I. Genetic heterogeneity in typical retinitis pigmentosa.
A nationwide, multicenter study of typical retinitis pigmentosa (RP) was carried out in collaboration with 18 hospitals throughout Japan to obtain current information for genetic counseling. We analyzed the genetic heterogeneity of RP based on the parental consanguinity of 434 probands registered during a 6-month period in 1990. A gradual decline in the frequency of consanguineous marriage was recognized among the normal parents of RP patients. The relative frequencies of inheritance patterns were estimated as: autosomal recessive, 25.2%; autosomal dominant, 16.9%; X-linked, 1.6%; and simplex, 56.3%. A comparison of these results with previous reports in Japan revealed a decline in the relative frequency of autosomal recessive cases and an increase in simplex cases. This suggests a decrease in the incidence of autosomal recessive retinitis pigmentosa in Japan, as well as the necessity for exhaustive investigations aimed at identifying inheritance patterns for RP patients seeking genetic counseling.
Adolescent↗
Multicenter genetic study of retinitis pigmentosa in Japan: II. Prevalence of autosomal recessive retinitis pigmentosa.
Retinitis pigmentosa (RP) is a group of genetically heterogeneous diseases with autosomal recessive (AR), autosomal dominant, and X-linked modes of inheritance. Autosomal recessive retinitis pigmentosa (ARRP) is the most common form in Japan. A genetic analysis was done to determine the prevalence of ARRP indirectly, to provide an estimation of changing trends in the overall prevalence of RP. Data on the frequency of consanguinity and marriage year of normal parents of 59 ARRP patients were obtained from a nationwide multicenter survey of typical retinitis pigmentosa conducted in 1990. The gene frequency of ARRP was 0.01145 (Dahlberg's formula). In 1990, the number of young symptomatic ARRP patients decreased, while the number of patients aged 40 years and older increased. The total number of symptomatic ARRP patients in 1990 was nearly 21% higher than in 1970. Despite a dramatic decline in consanguinity in recent decades in Japan, the number of ARRP patients has increased. This increase is attributed to greater longevity and overall population growth. Our results suggest that the total number of RP patients has not decreased, and may even have increased.
Adolescent↗
Quantitative analysis of major histocompatibility complex class II-positive cells in posterior segment of Royal College of Surgeons rat eyes.
Potential antigen-presenting cells in the posterior segment of Royal College of Surgeons (RCS) rat eyes were analyzed quantitatively. Light microscopic immunohistochemistry was performed at postnatal days (P) 10, 20, 28, 42, 63, and 140 in the eyes of RCS rats and their congenic counterparts. Immunohistochemical studies were carried out using monoclonal antibodies against major histocompatibility complex (MHC) class II antigen (OX6), a cytoplasmic antigen in bone marrow-derived macrophages (ED1), a membrane antigen on resident tissue macrophages (ED2), and a microglia/macrophage marker (OX42). Some sections were stained by a double-labeling method using these antibodies. No MHC class II-positive cells were seen in dystrophic RCS rat retinas at P10. They were found, however, in the outer nuclear layer and debris of outer segments at P20. From P20 to P42 the number of cells increased, then decreased until P140. Congenic controls, however, showed no MHC class II-positive cells in the retina. Cells double-labeled with OX6 and ED1 were present in the outer nuclear layer at P42, but no OX6 or OX42 double-labeled cells were detected. Also, no ED2-positive cells were detected. Our results suggest that MHC class II-positive cells may play some role in retinal dystrophy.
Animals↗
Ectopic transcription and the possibility of RNA editing of the human arrestin gene.
PURPOSE: To investigate the ectopic transcription of arrestin in various human organs and tissues. METHODS: Reverse transcriptase-polymerase chain reaction was used to investigate the ectopic transcription of the arrestin gene in the retina, anterior capsule of the lens, iris, bulbar conjunctiva, muscle, skin, placenta, intestine, and human blood. In addition, we examined the expression of arrestin mRNA isolated from whole blood cells of patients with Oguchi disease who had the 1147delA mutation in the arrestin gene. RESULTS: Arrestin was expressed at the mRNA level in all our samples. The mRNA isolated from the blood cells of Oguchi patients was not associated with the same 1147delA mutation as was reported earlier in the arrestin gene but had the normal sequence. CONCLUSIONS: These results demonstrate the ectopic transcription of the arrestin gene in various tissues and also suggest the possibility of RNA editing in the blood cells of Oguchi patients.
Arrestin↗
Glutamate elevation in rabbit vitreous during transient ischemia-reperfusion.
PURPOSE: To investigate the response of the retina to an ischemic insult, we measured the levels of glutamate in the vitreous of rabbit eyes. METHODS: Ocular ischemia was induced in the vitreous of rabbit eyes by simultaneous ligature of the optic nerve, ciliary arteries, and extraocular muscles for 45 minutes. Contralateral eyes were subjected to a conjunctival peritomy to serve as sham-operated controls. Reperfusion was achieved by releasing the ligature. Eyes were enucleated at the end of the ischemic period or 15, 45, or 75 minutes after reperfusion. RESULTS: Analysis of the vitreous free amino acids showed a significant increase in glutamate levels in the operated eyes at the end of the ischemic period (P <.001) and after 15 minutes of reperfusion (P <.05) as compared with the contralateral, sham-operated eyes. Glutamine levels in the vitreous were unchanged throughout the study. CONCLUSIONS: These results show that glutamate, which is considered to be derived from synaptic release of the retinal neurons or accumulation due to a deterioration of glutamate uptake or a degradation system in the retina, was transiently elevated in the vitreous.
Animals↗
Analysis of the metallothionein gene in age-related macular degeneration.
PURPOSE: To analyze the expression of metallothionein in neovascular membranes in patients with age-related macular degeneration (AMD) and to compare the findings in patients with proliferative diabetic retinopathy and proliferative vitreoretinopathy with findings in normal retinal pigment epithelial (RPE) cells. METHODS: Semiquantitative reverse transcriptase-polymerase chain reaction and immunohistochemical examinations were performed. Sequence analysis was also carried out. RESULTS: Expression of the metallothionein-II gene was not statistically significant in proliferative membranes. Sequence analysis revealed that there were at least six polymorphisms in the metallothionein-II gene and three in the metallothionein-IA gene. However, no amino acid substitution was observed. Metallothionein expression was also observed by immunohistochemical techniques in RPE cells of neovascular membranes in AMD patients. CONCLUSIONS: Metallothionein was reported to be decreased in aged macular RPE and in some monkey retina with early onset of macular degeneration. However, our results suggest that the expression of the metallothionein-II gene in neovascular membranes in patients with AMD may be controlled like other proliferating cells.
Aged↗
Structures of two nortriterpenoid saponins from Stauntonia chinensis.
Two new nortriterpenoid saponins, designated yemuoside YM8 [1] and yemuoside YM9 [2], were isolated from Stauntonia chinensis. A new saponin 3 was obtained from the cleavage of the ester-glycoside linkage of 1 or 2. Structures were elucidated on the basis of chemical and physicochemical evidence.
Molecular Structure↗
Two cases of synovial chondromatosis of the subacromial bursa.
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Bursa, Synovial↗
The characteristics of congenital hypertrophy of retinal pigment epithelium in Turcot syndrome.
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Adenomatous Polyps↗
Intraocular hemangiopericytoma. A case report.
A 55-year-old man presented with a smoothly elevated solid choroidal mass with choroidal detachment in the temporal region of the left eye. Both fluorescein and indocyanine green angiography suggested a vascularized lesion such as an angioma. However, radiographic examination revealed a solid, circumscribed, dome-shaped mass. During a 3-month observation, the mass gradually enlarged and invaded the iris. The possibility of malignant melanoma could not be ruled out. Due to rapid and continued growth of the tumor, the eye was enucleated. Histopathologic examination revealed proliferation of spindle-shaped cells surrounding reticulin-positive vessels, which is characteristic of hemangiopericytoma. To our knowledge, this is only the fourth reported case of intraocular hemangiopericytoma and the first diagnosed in a male patient.
Choroid Neoplasms↗
Modulation of multidrug resistance by cepharanthine in fresh human gastrointestinal tumor cells.
Resistance to doxorubicin (DOX) is mainly due to the effect of P-glycoprotein encoded by the multidrug resistance (MDR) gene. Cepharanthine (CEP) has been shown to circumvent multidrug resistance in P-glycoprotein-expressing cell lines. In the present study, we investigated the augmentation of DOX sensitivity by CEP using an MTT assay, and assessed the correlation between DOX sensitivity and P-glycoprotein expression by flow cytometry, in highly purified fresh human tumor cells obtained from 73 cancer patients. DOX sensitivity was decreased in proportion to P-glycoprotein expression. The cytotoxicity of DOX was increased by CEP in tumor cells possessing low DOX sensitivity. Moreover, there was a significant correlation between the effect of CEP on cytotoxicity and P-glycoprotein expression. Thus, CEP might be able to circumvent DOX resistance in cancer patients.
ATP Binding Cassette Transporter, Subfamily B, Mem↗