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Biomedical subjects

J Yonemoto

Publications and source records attributed to J Yonemoto.

At least 37 records · Page 2Linked to original sources
PubMed1995

Epidemiologic characteristics of rhegmatogenous retinal detachment in Kumamoto, Japan.

BACKGROUND: The epidemiology of rhegmatogenous retinal detachment in Asians is not well known. We studied the epidemiologic characteristics of rhegmatogenous retinal detachment in Kumamoto, Japan. METHODS: The study was based on a retrospective chart review of hospital patients who were treated for primary rhegmatogenous retinal detachment in 1990. The data were collected from seven hospitals in the Kumamoto area. RESULTS: From a population of 1 840 000, 192 residents developed retinal detachment. The annual incidence was therefore 10.4 per 100 000 population (9.6 for males, 11.2 for females). The incidences of three types of detachment-nontraumatic phakic, aphakic, and blunt trauma--were 9.8, 0.5 and 0.2 per 100 000 population, respectively. In 109 of 180 patients (60.6%) with nontraumatic phakic detachment, retinal breaks were associated with lattice degeneration. In females, 14 of 106 nontraumatic phakic cases (13.2%) were secondary to macular holes. CONCLUSION: Compared with previously published studies from other countries, the incidence of detachments associated with lattice degeneration and macular hole was higher, while the incidences of aphakic detachment and detachment due to blunt trauma were lower in Japan. Racial factors and living habits may affect the development of retinal detachment.

Adolescent↗
PubMed1994

The age of onset of posterior vitreous detachment.

The age of onset of posterior vitreous detachment (PVD) was studied in 930 eyes with a clearly defined onset time and no vitreoretinal diseases except refractive error or equatorial degeneration. We found a positive correlation between onset age of PVD and refractive error, with the regression line y = 0.91 x + 60.93 (y onset age, x diopter of refractive error). The higher the degree of myopia, the younger the onset age of PVD. Comparing onset ages for 240 eyes from males and 690 eyes from females, there was a possible tendency toward a lower PVD onset age for females. There was no significant difference in onset age between 112 eyes with and 818 eyes without equatorial degeneration of the retina.

Adult↗
PubMed1993

In vitro assessment of teratogenic potential of organotin compounds using rat embryo limb bud cell cultures.

Assessment of the relative teratogenic potential of bis(tri-n-butyltin)oxide (TBTO), tri-n-butyltin chloride (TBT), and its metabolites, i.e., (3-OH)hydroxybutyl dibutyltin chloride ((3-OH-Bu)DBT), di-n-butyltin dichloride (DBT), and butyltin trichloride (MBT) have been conducted using rat embryo limb bud cell cultures (LBC) to gain some knowledge of TBT embryotoxicity and DBT teratogenicity. Triphenyltin chloride (TPT), trimethyltin chloride (TMT), and triethyltin bromide (TET) have also been tested to obtain data for validation of LBC as a teratogen prescreening for organotin compounds. Fifty percent inhibition concentration for cell proliferation (IP50), and for cell differentiation (ID50), and the ratio of the former to the latter (P/D ratio) were obtained. The ID50 values in increasing order were as follows; TPT, DBT < TBT, TBTO < (3-OH-Bu)DBT < TET < TMT << MBT. With the exception of MBT, organotin compounds tested were very strong inhibitors of cell differentiation (ID50; 0.13-1.71 microM) and cell proliferation (IP50; 0.12-2.81 microM). P/D ratios for TBT, (3-OH-Bu)DBT, DBT and MBT were 1.0, 1.43, 1.32 and 1.08, respectively. These results suggest that the proximal toxin of DBT teratogenicity is DBT itself, and TBT is rather embryocidal than teratogenic so that TBT might mask the teratogenic and/or fetotoxic effects of its metabolites.

Abnormalities, Drug-Induced↗
PubMed1993

Vitreous hemorrhage associated with acute posterior vitreous detachment--a case report.

A case of vitreous hemorrhage associated with acute posterior vitreous detachment was reported. The patient was a 64-year-old man who complained of floaters in his left eye of one-week duration. His previous medical and ocular histories were unremarkable. Slit-lamp examination with Goldmann three-mirror contact lens showed complete posterior vitreous detachment in both eyes. Ophthalmoscopic examination and fluorescein angiogram revealed a partial defect in retinal blood flow in the midperipheral area of the superotemporal region of the left fundus. On follow-up examination, recovery of the retinal circulation was observed in that region and the vitreous hemorrhage had spontaneously resolved. The diagnosis was made in the left eye of rupture of retinal vein due to vitreous traction associated with acute posterior vitreous detachment without retinal break formation.

Acute Disease↗
PubMed1991

Neovascularization of the iris in rhegmatogenous retinal detachment.

To identify conditions associated with neovascularization of the iris in rhegmatogenous retinal detachment, we examined 36 eyes with this disorder seen at our hospital between 1979 and 1990. Clinical courses of disease were divided into the following three groups: (1) neovascularization of the iris without a history of a vitreoretinal operation (four eyes), (2) neovascularization of the iris after an unsuccessful vitreoretinal operation (26 eyes), and (3) neovascularization of the iris after surgical complications (six eyes). In all eyes of Groups 1 and 2, retinal detachment persisted at the onset of iris neovascularization; however, in six eyes, iris neovascularization subsided after retinal reattachment. Characteristic features of Groups 2 and 3 were patient age of 50 years or more, severe myopia, a history of increased intraocular pressure, a history of choroidal detachment, and a large scleral buckle.

Age Factors↗
PubMed1991

Comparative study of clinical factors that predispose patients to proliferative vitreoretinopathy in aphakia.

To clarify the risk factors of proliferative vitreoretinopathy (PVR) in aphakia, the clinical features of 25 aphakic eyes with PVR were statistically analyzed and compared with a control group of 157 aphakic eyes with non-PVR rhegmatogenous retinal detachment. The statistically significant (P less than 0.05) factors that predisposed patients to PVR in aphakia were as follows: a history of vitreous loss on cataract surgery, retinal detachment developing within 3 months after cataract extraction, duration of retinal detachment longer than 3 months, break larger than three disc diameters, and choroidal detachment. Vitreous loss is believed to play the most important role in the development of PVR in aphakia.

Adolescent↗
PubMed1991

Causative factors of retinal detachment in macular holes.

Two hundred nine macular holes of both pathologic myopia and idiopathic senile type were statistically analyzed to find out which factors cause retinal detachment in eyes with macular holes. The incidences of retinal detachment were as follows: 97.6% in myopia over -8.25 D, 67.7% in myopia between -8.0 and -3.25 D, and 1.1% in eyes under -3.0 D; 100% in widespread chorioretinal atrophy, 90.6% in spotty or lineal chorioretinal atrophy, 64.3% in myopic tigroid fundus, and 0% in eyes without myopic tigroid or atrophy; 96.0% in eyes with posterior staphyloma and 8.2% in eyes without it; 56.4% in posterior vitreous detachment [PVD] (+) eyes, 53.3% in PVD(+/-) eyes, and 51.9% in PVD(-) eyes. The statistically significant (P less than 0.05) factors that caused retinal detachment were refractive error, myopic chorioretinal change, and posterior staphyloma. There was no statistically significant difference regarding PVD.

Atrophy↗
PubMed1989

Effects of instillation of fly ash in the lung: physiochemical properties and immune responses.

In this study, we examined physiochemical properties of fly ash and aluminum silicate and investigated the effects of these compounds on IgE antibody production and macrophage response in the lung. Fly ash was round in shape, and aluminum silicate was indefinite in shape with respirable size. Both compounds consisted of alumina and silica as the main elements with respirable size. Enhanced IgE and IgG antiovalbumin (OA) antibody production was observed in mice first instilled intratracheally with the aluminum compounds and then given OA aerosol exposure. Histopathologic observations after instillation of fly ash and aluminum silicate showed that a large number of macrophages had ingested the compounds. However, the amount of free compound and the distribution of macrophages were different in mice given fly ash from those given aluminum silicate. These data indicate that particles of fly ash and aluminum silicate instilled into lung act as adjuvant for the production of IgE and IgG antibodies.

Administration, Inhalation↗
PubMed1985

Methylmercury stimulates the exhalation of volatile selenium and potentiates the toxicity of selenite.

The aim of the present experiments was to investigate whether a single dose of 24 mumol/kg methylmercuric chloride (MeHgCl) in rats can influence the effect of an equimolar dose of sodium selenite (Na2SeO3) on body weight or the exhalation of dimethylselenide, a volatile metabolic product of selenium. Due to the difference in their single-dose toxicities, only selenite depressed body weight gain, when given alone. The experiments indicated that methylmercury, irrespective of whether it was given 1-2 h before, or at the same time as sodium selenite, potentiated the effect of the latter on body weight. Methylmercury also increased the exhalation of volatile selenium, but this effect decreased when the administration of selenite was delayed.

Animals↗
PubMed1984

Normal organic and inorganic mercury levels in the human feto-placental system.

To clarify the normal metabolism of mercurials in the human feto-placental system, organic (or methyl) mercury and inorganic mercury were measured in maternal blood (MB), umbilical cord blood (UB), and chorionic tissues of the placenta (PC) and its blood vessels (PV), obtained from pregnant women just after delivery, as well as in fetal liver and fetal brain from induced abortion cases. Organic mercury was commonly detected in MB, UB, PC and PV, with slightly more elevated values in UB and PC than in MB, whereas inorganic mercury was detected in PC and PV, but not in MB and UB. In the fetal liver, 27-60% of mercury was in the form of inorganic mercury, whilst in four of five fetal brain samples, inorganic mercury was not detected. Additionally, fetal liver demethylation activity was studied in vitro. Incubation of methyl mercury with chopped fetal liver tissue for 24 h resulted in demethylation of approximately 1% of the methyl mercury.

Dealkylation↗
PubMed1984

Toxic effects of selenodiglutathione on pregnant mice.

A single dose of selenodiglutathione (GSSeSG) or sodium selenite (SS) was injected i.v. into pregnant CD-1 mice on day 12 of gestation at dosages varying from 16.4-32.0 mumol/kg body weight. Dose-dependent elevation of maternal death rates was observed for both treatments, and the slope of the dose-response curve was significantly steeper following GSSeSG treatment. However, fetotoxic effects were not different between the treatments.

Animals↗
PubMed1984

Effects of dimethoxyethyl phthalate, monomethoxyethyl phthalate, 2-methoxyethanol and methoxyacetic acid on post implantation rat embryos in culture.

The secondary metabolite of dimethoxyethyl phthalate (DMEP), methoxyacetic acid (MAA), but neither the diester nor either of its primary metabolites, monomethoxyethyl phthalate (MMEP) and 2-methoxyethanol (ME), interferes with normal growth and development of organogenesis phase rat embryos in culture. These in vitro observations suggest that the teratogenicity of DMEP in vivo is due to enzymic cleavage of the diester to ME, followed by oxidation of the latter to MAA in the maternal compartment.

Acetates↗
PubMed1983

Toxic effects of sodium selenite on pregnant mice and modification of the effects by vitamin E or reduced glutathione.

Toxic effects of sodium selenite (SS) on dams and/or conceptuses and modification of the effects by vitamin E (VE) or reduced glutathione (GSH) were investigated in pregnant mice during late gestation. Dose-dependent fetocidal effects and fetal growth retardation were observed in mothers injected SC with SS on day 12 but not on day 16 of gestation. On day 12, abortion occurred only at a dose level of 58.8 mumol/kg SS, whereas on day 16 it occurred at two dose levels: 27.2 and 40.0 mumol/kg SS. Pregnant mice were treated with or without VE (50 mg/kg, SC, daily from day 7 to day 11) and injected with a single dose of SS (46.2 mumol/kg, SC) on day 12. VE prevented abortion and maternal death, but none of the other effects such as fetal loss, fetal growth retardation, and decrease in body weight gain of the dams. Pretreatment with GSH (0, 2, or 5 mM/kg, SC) 20 min before SS injection on day 12 exacerbated maternal death, abortion, and decrease in body weight gain of the dams. No effect were observed in the number of live offspring, and in body weight of offspring.

Abortion, Spontaneous↗
PubMed1979

Automatic classification of electroencephalograms: Kullback-Leibler nearest neighbor rules.

A prototypic problem in screening of electroencephalograms in the automatic classification of stationary electroencephalogram time series is treated here by the Kullback-Leibler nearest neighbor rule approach. In that problem, the category or state of an individual is classified by comparison of his or her electroencephalogram with those taken from other individuals in the alternative categories. The Kullback-Leibler nearest neighbor classification rules yield a statistically reliable estimate of the smallest possible probability of electroencephalogram misclassification with a relatively small number of labeled sample electroencephalograms. The automatic classification of anesthesia levels L1 and L3, respectively the anesthesia levels insufficient and sufficient for deep surgery, is treated by machine computation on the electroencephalogram alone.

Anesthetics↗