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Biomedical subjects

Y Miyake

Publications and source records attributed to Y Miyake.

At least 343 records · Page 19Linked to original sources
PubMed1992

Anesthetically blocked optic nerve conduction in congenital stationary night blindness.

It has been hypothesized that the negative configuration of the electroretinogram (ERG) in congenital stationary night blindness (CSNB) may change to a positive configuration following loss of the inhibitory function of the optic nerve centrifugal fibers. In order to study this hypothesis, the ERGs before and after blocking optic nerve conduction by retrobulbar anesthesia were recorded in a patient with CSNB, who had retinal breaks and was being treated with cryopexy under retrobulbar anesthesia. After complete blockade of the optic nerve conduction induced by retrobulbar anesthesia, the ERG showed little change in comparison with that recorded before anesthesia. The above finding indicates that the temporary blockade of optic nerve conduction does not modify the ERG configuration in CSNB.

Anesthesia, Local↗
PubMed1992

Antibodies against human retinal proteins in serum from patients with cone dystrophy.

Eleven patients with cone dystrophy were examined for serum antibodies against human retinal proteins. Sera were screened by immunoblotting methods using human retinal proteins as antigens. Three cases from different families showed a distinct band at the molecular weight of 14 kDa; the hereditary pattern of these seropositive cases was autosomal recessive or sporadic with parental consanguinity. The serum antibodies were negative in the other sporadic or autosomal dominant cases of cone dystrophy with similar clinical features, in cases of various ocular diseases including macular dystrophies, and in healthy adults. No sera tested showed any specific antibodies against proteins from the human optic nerve or spinal cord.

Adolescent↗
PubMed1992

Japanese family with blue cone monochromatism.

The diagnosis of blue cone monochromatism (BCM) is based on severely affected color vision with preserved blue function, nearly nonrecordable photopic ERG, and a family pedigree compatible with X-linked inheritance. We have studied the color vision and ocular function of three members of a family with BCM and a female carrier in the same family. Two of the three affected family members, 9- and 7-year-old brothers, showed the unique features of BCM in their color vision and ERG. The third affected family member, a 43-year-old uncle, showed achromatic vision. He had diabetic retinopathy and moderate cataract which were thought to disturb his blue cone function, causing apparent rod monochromatism. The female carrier, the mother of the brothers, showed normal visual functions except for a slight reduction in photopic ERG amplitude. We believe that this is the first description of BCM in a Japanese family.

Adult↗
PubMed1992

Human tritanopia associated with two amino acid substitutions in the blue-sensitive opsin.

Tritanopia is an autosomal dominant genetic disorder of human vision characterize by a selective deficiency of blue spectral sensitivity. The defect is manifested within the retina and could be caused by a deficiency in function or numbers (or both) of blue-sensitive cone photoreceptors. We have used PCR, denaturing gradient gel electrophoresis, and DNA sequencing of amplified exons to detect in four of nine unrelated tritanopic subjects two different point mutations in the gene encoding the blue-sensitive opsin, each leading to an amino acid substitution. Segregation analysis within pedigrees and hybridization of oligonucleotides specific for each allele to DNA samples from control subjects support the hypothesis that these mutations cause tritanopia. These results complete the genetic evidence for the trichromatic theory of human color vision.

Arginine↗
PubMed1992

[The properties of visual functions and familial analysis in blue cone monochromatism].

The diagnosis of blue cone monochromatism (BCM) is based on severely affected color vision with preserved blue function, nearly absent photopic ERG, and a family pedigree compatible with X-linked inheritance. In the past, there has been no familial report of BCM in Japan. We found a Japanese family with BCM and studied the ocular findings of three affected members and a female carrier. Two of three affected members showed unique properties of BCM in their visual functions, including color vision and ERG. One affected member, a brother of their mother (43 years old), showed achromatic color vision. He had diabetic retinopathy and moderate cataract, which, might have disturbed his preserved blue cone function, resulting in the achromatic vision. A female carrier showed normal visual function, except that her photopic ERG was slightly reduced in amplitude.

Adult↗
PubMed1992

Batten disease--deteriorating course of ocular findings.

For over two years, we monitored the visual functions and ocular findings of two siblings with Batten disease. At the initial visit, the older patient was in the advanced stage of the disease, manifesting symptoms similar to those previously reported by many authors. The younger patient, on the other hand, was in the early stage of the disease at the time of the first visit. In the next 8 months, however, the visual acuity of the younger patient decreased rapidly, from 1.0 to below 0.1. Although the electroretinogram (ERG) showed a normal a-wave and a reduced b-wave when visual acuity was normal, repeated recordings of the ERG at each visit revealed rapid reduction of the b-wave. This finding seems to confirm the animal data, indicating that the primary lesion of the retina was in the inner layers. To our knowledge, this is the first report on these phenomena which may be unique to the deteriorating visual system in Batten disease and may facilitate early diagnosis.

Child↗
PubMed1991

Retroperitoneal neurilemoma presenting with humoral hypercalcemia associated with markedly elevated plasma prostaglandin levels.

A 72-year-old woman complaining of somnolence and thirst was diagnosed to have a hypercalcemic crisis (corrected serum calcium level, 17.4 mg/dl) associated with encephalopathy and nephropathy. Imaging diagnostic techniques demonstrated a retroperitoneal tumor at the median site of right renal pelvis. Hormonal studies revealed that plasma levels of thromboxane B2, prostaglandin (PG) E2, 6-keto prostaglandin F1 alpha (PGF1 alpha) and prostaglandin F2 alpha (PGF2 alpha) were markedly elevated. The tumor was successfully removed by operation; her serum calcium level and PG levels normalized without any treatment indicating that this case belongs to the category of humoral hypercalcemia of malignancy (HHM). Pathologically, this tumor was diagnosed to be a benign neurilemoma. Parathyroid hormone-related protein (PTHrP) radioimmunoassay and Northern blot hybridization for PTHrP mRNA were negative. The current case demonstrates that hypercalcemic crisis could be induced by a curable benign neurilemoma, and suggests that this HHM-like morbidity was associated with markedly elevated plasma PG levels.

Aged↗
PubMed1991

Leucine zipper motif in porcine renin-binding protein (RnBP) and its relationship to the formation of an RnBP-renin heterodimer and an RnBP homodimer.

An apparent leucine zipper motif was recognized in the predicted amino acid sequence of porcine kidney renin-binding protein (RnBP) by analysis of the nucleotide sequence of a cDNA encoding the protein (Inoue, H., Fukui, K., Takahashi, S., and Miyake, Y. (1990) J. Biol. Chem. 265, 6556-6561). To evaluate the role of this motif in the formation of an RnBP-renin heterodimer and an RnBP homodimer, a porcine mutant cDNA involving Leu185----Asp and Leu192----Asp substitutions was constructed and expressed in vitro and in Xenopus oocytes. The mutant protein neither binds to renin nor forms the homodimer. The results strongly suggest that the leucine zipper motif in the RnBP molecule mediates the formation of both the RnBP-renin heterodimer and the RnBP homodimer observed previously. The existence of the motif should facilitate elucidation of the role of RnBP in renin metabolism.

Amino Acid Sequence↗
PubMed1991

Suppression of penicillin-induced lysis of Staphylococcus aureus by cibacron blue 3G-A.

The effect of cibacron blue 3G-A (CB) on bacteriolysis induced by penicillin G was investigated using Staphylococcus aureus FDA 209P. Penicillin-induced lysis was completely inhibited by 30 microM CB. However, the bactericidal effect of penicillin G was not influenced by CB. These results indicate that a bacteriolytic process is not essential for penicillin to kill S. aureus.

Bacteriolysis↗
PubMed1991

Application of an ovomucoid-conjugated polymer column for the enantiospecific determination of chlorprenaline concentrations in plasma.

An ovomucoid-conjugated polymer column was prepared for the liquid chromatographic resolution of racemic compounds. The column showed strong retention of acidic solutes, a characteristic attributed to the structure of the stationary phase support gel. Although the efficiency of the column was lower than that of an ovomucoid-conjugated silica gel column, enantiospecific chlorprenaline determination in plasma was achieved with solute amounts from 1.0 ng to 0.1 microgram.

Chromatography, High Pressure Liquid↗
PubMed1991

Electroretinographic monitoring of retinal function during eye surgery.

We performed a pilot study of electroretinographic monitoring of retinal function during eye surgery performed with local anesthesia. A contact lens with a built-in light-emitting diode was sterilized and used as both a stimulus source and a recording electrode for 30-Hz flicker electroretinograms. Each recording required 7 seconds, during which the operating light (but not the room light) was switched off. Electroretinograms recorded during surgery on 10 patients with minimal retinal abnormality were evaluated for the effects of light adaptation caused by regular exposure to an operating light source or operating microscope. The fluctuations of the amplitude and peak time were small, indicating that this technique can be used to monitor retinal function during eye surgery. Some results during retinal and vitreous surgeries are shown.

Contact Lenses↗
PubMed1991

Effect of temperature on electroretinograph readings during closed vitrectomy in humans.

To determine whether intraocular cooling using room-temperature irrigating solution can cause abnormal electroretinograph readings, we operated on six patients with premacular fibrosis and minimal retinal detachment, measuring the temperature in the vitreous cavity and using an electroretinographic monitor. The temperature in the vitreous cavity dropped to 27 degrees C to 28 degrees C after vitrectomies during which room-temperature solutions were used. This resulted in abnormal electroretinograph readings (markedly delayed peak times and reduced amplitudes). These results suggest that the routinely used room-temperature solution affects retinal function during vitrectomy; however, this functional change was reversible in patients having only minimal retinal abnormality.

Body Temperature↗
PubMed1991

Polysaccharide-coated oil droplets in oil-in-water emulsions as targetable carriers for lipophilic drugs.

Surface of oil droplets in an oil-in-water (o/w) emulsion were coated with naturally occurring polysaccharides (such as mannan, amylopectin, and pullulan) which were, in part, bearing a cholesterol moiety. The mean size of the colloidal droplets was not altered much, even by coating with the polysaccharide derivatives, while the surface charge of the droplet decreased upon coating. Mannan and amylopectin derivative-coated droplets aggregated upon addition of Concanavalin A. These observations suggest that the terminal sugar moiety of the specific polysaccharides on the surface of colloidal droplets can be recognized by lectin. After intravenous injection of the emulsions into guinea pigs, kinetics of the blood clearance and the tissue distribution of the polysaccharide-coated oil droplets, which contain [14C]coenzyme Q10 as the marker, were investigated. In the initial rapid phase of blood clearance of the radioactivity, the polysaccharide-coated droplets were cleared from the blood stream slower than the uncoated ones. The lung uptake of the mannan derivative-coated droplet emulsion at 30 min after intravenous injection was approximately 15 times higher than that of the conventional emulsion without the polysaccharide coat.

Animals↗
PubMed1991

A new multiple-unit oral floating dosage system. I: Preparation and in vitro evaluation of floating and sustained-release characteristics.

A multiple-unit type of oral floating dosage system, (a new type of floating pills which generate carbon dioxide gas) has been prepared in order to prolong the gastric emptying time (GET) of the preparation. The floating ability and the sustained-release characteristics of the system have been elucidated in vitro. The system was composed of sustained-release pills as seeds and double layers on the sustained-release pills. The inner layer was an effervescent layer containing both sodium bicarbonate and tartaric acid. The outer layer was a swellable membrane layer containing mainly polyvinyl acetate and purified shellac. When the system was immersed in water, it formed swollen pills, like balloons, with a density much lower than 1.0 g/mL. The reaction was due to carbon dioxide gas generated by neutralization in the effervescent layer with the diffusion of water through the swellable membrane layer. The system was floating completely within approximately 10 min and approximately 80% remained floating over a period of 5 h irrespective of pH and viscosity of the test medium. While the system was floating, a drug (p-aminobenzoic acid) was released. The release rate of the drug from the system was zero order and depended on the sustained-release characteristics of the sustained-release seeds composing the system. The release rate was not affected by the amount of the swellable membrane layer up to 13% (w/w).

Administration, Oral↗
PubMed1991

Cibacron blue 3G-A inhibits cell separation of gram-positive bacteria.

A triazine dye, Cibacron blue 3G-A (CB), is an inhibitor of cell separation of staphylococcal spp. therefore, we examined the effect of CB on growth of gram-positive bacteria other than Staphylococcus. CB added to the medium of growing cultures of strains of genus Micrococcus, Streptococcus, Lactobacillus and Bacillus caused inhibition of cell separation. Moreover, in case of Bacillus and Lactobacillus, individual cells were elongated as filament. Strains of the genus Micrococcus were as sensitive to CB as genus Staphylococcus in which the minimum concentrations of CB needed for inhibition of cell separation ranged from 15 to 100 microM. Other strains belong to genus Streptococcus, Bacillus and Lactobacillus were less sensitive; the minimum concentrations were 100 microM--25 mM.

Bacillus↗