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Biomedical subjects

T Miki

Publications and source records attributed to T Miki.

At least 1,081 records · Page 60Linked to original sources
PubMedDate not supplied

High-resolution separation of PCR product and gene diagnosis by capillary gel electrophoresis.

High-resolution separation of a PCR product from a mixture of DNA restriction fragments was achieved using capillary gel electrophoresis. The capillary gel electrophoretic separation gives an excellent resolution of two fragments of the 500-bp PCR product and the 506-bp DNA fragment, which differs by only 6 bp, and the complete separation of a broader chain length range of DNA afragments up to 12 kbp within 20 min. The plate number of gel-filled capillary was achieved to be 2 million plates per meter. Capillary gel electrophoresis is applied to the gene diagnosis for heart disease through apolipoprotein E genotyping. The advantages and limitations of capillary gel electrophoresis in the application to PCR analysis and DNA diagnosis are discussed.

Apolipoproteins E↗
PubMedDate not supplied

Clinical comparison of Alzheimer's disease in pedigrees with the codon 717 Val-->Ile mutation in the amyloid precursor protein gene.

Alzheimer's disease (AD) is the most common cause of dementia (32). Although the majority of cases of AD are sporadic, the most consistent risk factor detected in several epidemiological studies has been a positive family history of the disease (14,21). In addition, many large pedigrees have been described in which AD appears to be inherited as an autosomal dominant disorder. In one such pedigree (F23) a point mutation within the beta-amyloid precursor protein (APP) gene at codon 717 was identified and hypothesized to be pathogenic (10). The mutation results in a valine to isoleucine change in APP (APP717 Val-->Ile). Subsequent screening has revealed four other pedigrees, detailed in this study, in which this mutation co-segregates with AD (13,26,37). In addition, one other pedigree (Tor3) with this mutation has been described (15) and detailed clinical, neuropsychological, and neuropathological data are reported. Tor3 is discussed below in comparison to the findings in the families in this study. The five families we report with the mutation were identified in Britain (1 family), the United States (1 family), and Japan (3 families). The mutation has not been reported in the general population of any of these countries (3,13,26,33). On this basis alone it seems this mutation is pathogenic. Other APP codon 717 mutations have been identified which co-segregate with the disease (4,25). Also, a double mutation in APP at codons 670/671 has been shown to cosegregate with the disease in two large Swedish pedigrees (22). In all cases, there is complete co-segregation of the APP mutation with early onset AD, providing overwhelming statistical evidence that these mutations are pathogenic. We present the clinical features and limited neuropathology of AD in these families with the APP 717 Val-->Ile mutation.

Adult↗
PubMedDate not supplied

Electron spin resonance of bloodstains and its application to the estimation of time after bleeding.

The degradation of blood constituents in unheparinized dry blood was studied with electron spin resonance (ESR) at various temperatures. The intensity of ESR signals of methemoglobins, non-heme irons and organic radicals in dried human blood increases with time. Considering the kinetics of the signal growth, the formation mechanism of the paramagnetic species was discussed. The ESR signal (g = 4.3) of non-heme iron is usable in estimating the time after bleeding or injury using bloodstains.

Animals↗
PubMedDate not supplied

Accumulation of photosensitizer ATX-S10 (Na) in experimental corneal neovascularization.

PURPOSE: To determine the most appropriate time for laser irradiation to produce selective occlusion of new corneal vessels by photodynamic therapy (PDT) with a new photosensitizer, ATX-S10(Na). METHODS: The time course of the plasma levels of ATX-S10(Na) and the degree of dye accumulation in the corneal neovascularization after intravenous administration was determined in rabbit eyes. Plasma concentration of ATX-S10(Na) was analyzed by a spectrophotometer. The amount of ATX-S10(Na) in the new corneal vessels was measured by nitrogen-pulsed laser spectrofluorometry. Frozen sections of neovascularized cornea and iris were observed by fluorescence microscopy. RESULTS: Plasma ATX-S10(Na) concentration was highest 5 minutes after dye injection and rapidly decreased and reached almost zero at 24 hours, indicating its prompt excretion from the body. The amount of ATX-S10(Na) in the new corneal vessels as measured by nitrogen-pulsed laser spectrofluorometry increased and reached maximal level at 2 to 4 hours. Under fluorescence microscopy, the dye was more abundantly localized in the wall of new corneal vessels than in the normal tissue at 2 to 4 hours. CONCLUSION: These results indicate that laser irradiation between 2 and 4 hours after dye injection is appropriate for selective PDT with ATX-S10(Na) for the occlusion of new corneal vessels.

Animals↗
PubMedDate not supplied

A retrospective pilot study of indocyanine green enhanced diode laser photocoagulation for subfoveal choroidal neovascularization associated with age-related macular degeneration.

PURPOSE: The effectiveness and limitations of indocyanine green (ICG) enhanced diode laser photocoagulation in treating subfoveal choroidal neovascularization (CNV) associated with age-related macular degeneration (AMD) were investigated retrospectively. METHODS: Thirty-eight eyes of 37 patients with subfoveal CNV received ICG enhanced diode laser (wavelength, 805 nm) photocoagulation in our preliminary series. Nineteen eyes had classic CNV and the others had occult CNV, which was well-delineated on ICG angiography. The rate of anatomical success and functional outcomes were investigated. Factors prognostic of a final visual acuity of 0.1 or better were analyzed. The follow-up period ranged from 6 to 51 months (mean +/- SD = 26.5 +/- 14.4 months). RESULTS: Occlusion of CNV was achieved in 35 of 38 eyes (92%), and 7 eyes (18%) showed recurrence, which was occluded by retreatment in all but 1 eye. Ten eyes (26.3%) showed improvement of visual acuity; 16 (42.1%) showed no change; and in 12 eyes (31.6%) visual acuity deteriorated. Factors prognostic of a final visual acuity of 0.1 or better were good preoperative visual acuity (Mann-Whitney U-test, P =.0028), and a relatively short distance between the edge of laser burns and the center of the foveal avascular zone (unpaired t-test, P =.0285). CONCLUSION: Indocyanine green enhanced photocoagulation achieved a higher anatomical success rate but functional outcomes equal to those with argon or krypton laser photocoagulation. A controlled prospective study is necessary to prove the efficacy of this treatment.

Aged↗
PubMedDate not supplied

Indocyanine green angiograms of choroidal nevi. comparison between confocal and nonconfocal scanning laser ophthalmoscope and fundus video camera.

PURPOSE: A fundus video camera and a nonconfocal scanning laser ophthalmoscope (SLO) detect direct light and indirect light, whereas a confocal SLO detects mostly direct light. Differences in confocal and nonconfocal SLO images and fundus video camera images are most likely due to their different optical systems. These differences were examined in indocyanine green (ICG) angiograms of a choroidal nevus. METHODS: A confocal SLO, a nonconfocal SLO, and a high resolution digital fundus video camera were used to obtain ICG angiograms of pigmented choroidal nevi in 4 patients for 30 minutes following dye injection. RESULTS: All the angiograms showed a hypofluorescent region in the nevus until 10-14 minutes after dye injection, except in 1 patient in whom no hypofluorescent region was seen in an early confocal-SLO angiogram. From 20 minutes to 30 minutes postinjection, the hypofluorescent regions were still visible in all fundus video camera angiograms and nonconfocal SLO angiograms but not in confocal SLO angiograms. CONCLUSIONS: Early angiograms taken with the three angiography systems showed a similar appearance of the choroidal nevus. However, late ICG angiograms with a confocal SLO showed different images from those taken with a nonconfocal SLO or a fundus video camera. It is suggested that the angiography system and the aperture size of an SLO should be selected according to the aspect of the pigmented choroidal nevus that is of interest in late-phase ICG angiography.

Adult↗
PubMedDate not supplied

Rapid injection of indocyanine green dye for evaluation of choroidal venous circulation.

PURPOSE: The purpose of this study was to investigate the effects of rapid intravenous administration of a small bolus of indocyanine green (ICG) dye on early phase findings of ICG angiography. METHODS: Rabbit eyes were used. Ten normal eyes, 5 eyes with occlusion of vortex veins, and 5 eyes with chorioretinal atrophy were examined by ICG angiography, and early-phase findings after a rapid injection of a small bolus of dye were compared with those obtained with an ordinary injection. RESULTS: In normal eyes, after the rapid injection it was possible to visualize some small bright fluorescent boluses in the choroidal veins from 6 to 12 seconds after injection, while with the ordinary injection they were unclear. In eyes with occlusion of vortex veins, the rapid injection resulted in visualization of the choroidal veins with delayed filling against the background, and the region of the choroidal veins with delayed filling could easily be determined. In eyes with chorioretinal atrophy, only the rapid injection clearly revealed the choroidal veins with delayed filling. CONCLUSIONS: The rapid injection made it possible to detect the choroidal veins with delayed filling that were not clearly and easily visible using an ordinary injection. Rapid injection of ICG dye is useful for a detailed examination of choroidal circulation.

Animals↗
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A case of glaucoma with choroidal hemangioma managed by nonpenetrating trabeculectomy.

BACKGROUND: Nonpenetrating trabeculectomy was used in a patient with glaucoma complicated by diffuse choroidal hemangioma. CASE: A 12-year-old boy suffered from glaucoma with choroidal hemangioma in the left eye. Intraocular pressure was 28 mm Hg and visual acuity was 0.04. Nonpenetrating trabeculectomy was then performed. OBSERVATIONS: Postoperative intraocular pressure was controlled at around 15 mm Hg with pilocarpine hydrochloride eye drops. Visual acuity and visual field were preserved over 19 months after the operation. CONCLUSIONS: An increase in aqueous outflow resistance was considered to be the major mechanism in the rise in intraocular pressure, based on distinct dilatation and tortuosity of the episcleral blood vessels and congestion of Schlemm's canal. Therefore, construction of aqueous drainage by nonpenetrating trabeculectomy was effective. Retaining the trabecular meshwork was also considered effective in controlling complications such as choroidal hemorrhage and postoperative flat anterior chamber.

Angiography↗
PubMedDate not supplied

The relationship between gap-junctional intercellular communication and the proliferative activity of retinal pigment epithelial cells.

PURPOSE: To investigate the relationship between gap-junction mediated intercellular communication and the proliferative activity of retinal pigment epithelial cells in the retinal tear base. METHODS Retinal tears were created experimentally in white rabbits, and the changes of intercellular communication via gap junctions between retinal pigment epithelial cells in the retinal tear base were investigated using the dye-coupling method, which involves observing the spread of a fluorescent dye, Lucifer Yellow CH. In addition, the proliferative activity of these cells was investigated using an antibody for proliferating cell nuclear antigen and was compared with the changes in intercellular communication. RESULTS: Immediately after the creation of retinal tears, extensive spreading of Lucifer Yellow CH into adjacent cells was observed, which was markedly reduced 1 week later. After 1 month, the spreading of dye to adjacent cells was observed again. On the other hand, proliferative activity was enhanced at 1 week after retinal tear creation and was reduced again after 1 month. CONCLUSIONS: It is known that tumor cells with enhanced proliferative activity show decreased intercellular communication via gap junctions. The present study suggests a possible relationship between intercellular communication and the proliferative activity of retinal pigment epithelial cells in the base of retinal tears.

Animals↗
PubMedDate not supplied

Treatment parameters for the efficacy of transscleral cyclophotocoagulation in rabbits using a diode laser.

PURPOSE: To determine parameters for the efficacy of transscleral cyclophotocoagulation (TSCPC) using a diode laser. METHODS: We performed TSCPC on 74 pigmented rabbits with different exposure powers and varying number of applications, followed by clinical observation and histological examination up to 24 weeks. RESULTS: Based on observation of the clinical course, the most favorable parameters were 600 mW and 36 or 48 applications, which did not cause severe complications and sufficiently lowered intraocular pressure (IOP). Histological examination revealed coagulation of the epitheliums and stroma of the ciliary body at 600 mW. The stroma of the ciliary body was severely damaged at 900 mW. CONCLUSIONS: Transscleral cyclophotocoagulation at 600 mW with a larger number of applications than previously reported did not cause severe complications and effected greater and more lasting lowering of IOP than TSCPC with more intense coagulation and fewer applications.

Animals↗