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Biomedical subjects

Y Miyake

Publications and source records attributed to Y Miyake.

At least 163 records · Page 9Linked to original sources
PubMed1999

Postural adjustment response to depth direction moving patterns produced by virtual reality graphics.

PURPOSE: Human posture is controlled by a combination of vestibular, somatosensory and visual information. This paper is concerned with postural readjustment responses induced by vection. In the visual control of posture, visually-induced perception of self-motion plays an important role and is called vection. Vection is difficult to measure quantitatively because it is a highly subjective phenomenon. HYPOTHESIS: An optokinetic stimulus that moves in depth induces vection. We hypothesize that the magnitude of the visually-induced body sway is correlated with the degree of vection. METHODS: A depth optokinetic stimulus (DOKS) was projected onto a head-mounted display (HMD) worn by standing subjects. The DOKS consisted of a random dot pattern that was perceived three-dimensionally and moved in depth sinusoidally. Vection was estimated in two ways, a verbal assessment and a joystick maneuver. In addition, visually-induced body sway was measured by monitoring five reference points on the body by two video-motion analyzers. RESULTS: The magnitude of the subjective vection was highly correlated with visually-induced body sway and was strongly dependent on the velocity of the visual stimulus. The ankle joint was pivoted during visually-induced body sway and acted as a motion initiator. When the magnitude of body sway was large, the body movement was adjusted at the hip and head-neck joints. CONCLUSIONS: The high correlation between vection and body sway suggests that vection can be estimated quantitatively by measuring visually-induced body sway.

Adult↗
PubMed1999

[A young male of systemic lupus erythematosus with hepatic lesions showing multiple low density spots in CT of liver].

A 19-year-old man was admitted to our hospital due to low grade fever and polyarthralgia with history of photosensitivity. Laboratory findings showed the elevated transaminases, leukocytopenia and thrombocytopenia. Examinations in regard to autoimmune diseases revealed the positive antinuclear antibody and positive LE test. The computed tomography (CT) showed the multiple low density spots in liver. CT guided liver biopsy specimens regarding to these low density spots showed the hepatic lesions with mild inflammatory cell infiltration and subtle piecemeal necrosis. The patient was diagnosed as systemic lupus erythematosus (SLE) with hepatic lesions based on the clinical symptoms and the laboratory data. Rheumatoid arthritis was excluded because of intact joints X-ray findings. Autoimmune hepatitis was also denied because of the fulfillment of definite diagnostic criteria of SLE and minimal histological changes of liver. Prednisolone therapy improved his clinical manifestations and normalized both the laboratory data of liver function and the immunological abnormalities in SLE, so the multiple spots in CT of liver also disappeared.

Adult↗
PubMed1999

[Two cases in which the presence of ciliospinal response led to indecisiveness in the evaluation of brain death].

The ciliospinal reflex was first described by Budge in 1852. This reflex is used as an indicator of brain stem and autonomic nervous system functioning. In the Japanese guideline for determining brain death, the absence of this reflex is considered essential. We reported two cases in which the ciliospinal responses judged to be present resulted in the authors' indecision in determining brain death. They were the cases of a 74-year-old woman who suffered a right putaminal hemorrhage and that of a 28 year-old male with severe head and cervical cord injury. Although brain death was suspected in both cases from its clinical courses, the fact that the ciliospinal reflex was present in each case kept us from declaring that these patients were in the state of brain death. The center of the ciliospinal reflex lies in the first three segments of the thoracic spinal segments and two pathways are involved in this reflex. A noxious stimulation to the face will be registered through the brain stem, but if stimulation is in the neck or upper trunk, it may go directly to the spinal center. Because of the latter pathway to the spinal center, this reflex might remain in patients in whom the brain stem is completely nonfunctioning. Therefore, the presence of this reflex dose not always preclude a state of brain death.

Adult↗
PubMed1999

Lipid peroxides and antioxidants in serum of neonatal calves.

OBJECTIVE: To examine the association between oxidative stress and antioxidants in neonatal calves after birth. SAMPLE POPULATION: Sera from 6 healthy Holstein-Friesian cows and 7 of their newborn calves were obtained at various intervals after birth. PROCEDURE: Lipid peroxides in serum of cows and their newborn calves were estimated by measuring concentrations of thiobarbituric acid-reactive substances (TBARS). The antioxidative activities of neonatal sera were evaluated by measuring their superoxide-scavenging activities, ferroxidase activities, and the concentration of bilirubin-associated albumin. RESULTS: Concentration of TBARS in neonatal sera within 1 day after birth was significantly higher than concentrations > or = 2 days after birth and concentrations in serum of the dams. In contrast, antioxidative activities of neonatal sera, evaluated on the basis of superoxide-scavenging activities, ferroxidase activities, and concentration of bilirubin-associated albumin 3 hours after birth, were significantly lower than antioxidative activities in sera of the dams. CONCLUSIONS: Susceptibility of calves to oxidative stress during the neonatal period may be explained by the immature defense system against superoxide radicals.

Animals↗
PubMed1999

Relationships between activity of daily living, and oral cavity care and the number of oral cavity microorganisms in patients with cerebrovascular diseases.

We examined the relationships among the activity of daily living (ADL), oral cavity care, and the number of oral cavity microorganisms in 40 patients with cerebrovascular diseases (CVD). The CVD patients were classified into 4 groups, I, II, III and IV based on their ADL and the method used for oral cavity care. The ADL was highest in group I and lowest in group III. Only the patients of only group III could not eat by themselves and were receiving naso-esophageal feeding. Oral cavity care was performed by the patients themselves in groups I and IV, but was performed by caregivers in groups II and III. The group IV patients had no teeth, but could eat by themselves using full dentures. The numbers of microorganisms in the pharyngeal swabs from the 4 groups were measured and expressed as colony-forming units (cfu). The numbers of both Staphylococci spp. and Candida spp. were significantly higher in group III than in the other groups. Moreover, Pseudomonas aeruginosa was isolated only from patients of group III (in about 66%). The oral cavity care by caregivers was almost the same in groups II and III, but the numbers of oral cavity microorganisms were significantly higher in group III than in group II. These results indicated that microorganisms grow more easily in the oral cavities of CVD patients with low ADL compared with CVD patients with higher ADL, and that eating is thought to be important for the prevention of an increase of microorganisms in the oral cavity.

Activities of Daily Living↗
PubMed1999

Amplitude increase of the multifocal electroretinogram during light adaptation.

PURPOSE: To determine using the multifocal ERG technique whether there are any regional differences in the increase in the amplitude of cone electroretinograms (ERGs) during light adaptation. METHODS: Multifocal ERGs were recorded with the Visual Evoked Response Imaging System from five normal subjects. Thirty-seven hexagonal stimulus elements and a recording time of 60 seconds were used. After 20 minutes of dark adaptation, multifocal ERGs were repeatedly recorded every 2 minutes over a period of 16 minutes. The amplitudes of the multifocal ERGs at different eccentricities were compared during the 16 minutes of light adaptation. RESULTS: During the 16 minutes of light adaptation, the summed responses of the multifocal ERGs increased in amplitude an average of 36% and 47% for the negative and positive components, respectively. The magnitude of increase was minimal in the central retina at 22% and was significantly larger in the peripheral retina at 58%. The implicit time was slightly increased (<4%) with light adaptation, but there were no regional differences. CONCLUSIONS: The results demonstrated that there are topographic variations in the amplitude increase of cone ERGs during light adaptation. This topographic variation indicates that the mechanism for the increase must be based on known regional differences in the retina.

Adaptation, Ocular↗
PubMed1999

Blue-on-yellow perimetry in the complete type of congenital stationary night blindness.

PURPOSE: To resolve the discrepancy between nonrecordable full-field short wavelength cone electroretinograms (S-cone ERGs) and the presence of normal color vision in patients with the complete type of congenital stationary night blindness (CSNB1). METHODS: Conventional white-on-white (W-W) perimetry, blue-on-yellow (B-Y) perimetry, and the Farnsworth-Munsell 100-hue test were performed in five patients with CSNB1. Diagnosis of CSNB1 was made by clinical and electrophysiological examinations. Twelve normal, age-matched control subjects and an additional 7 normal, highly myopic subjects were tested. RESULTS: Color vision was normal in all the CSNB1 patients by the Farnsworth-Munsell 100-hue test. B-Y perimetry demonstrated that blue cone sensitivity in CSNB1 was normal in the fixation area, but the mean sensitivities of the entire 60 degrees field, the central 0 degrees-to-15 degrees, and 15 degrees-to-30 degrees ring were significantly decreased compared with the normal and myopic subjects. The sensitivity difference between 15 degrees-to-30 degrees and 0 degrees-to-15 degrees in B-Y perimetry increased significantly in CSNB1 compared with both normal and myopic control subjects. CONCLUSIONS: Our perimetric results demonstrated that the S-cone function in CSNB1 is preserved only in the fovea and becomes abnormal toward the peripheral retina. This accounts for the normal color vision that tests mainly foveal function and the nonrecordable S-cone ERGs that arise mainly from peripheral retina.

Adolescent↗
PubMed1998

Alteration by maternal pinealectomy of fetal and neonatal melatonin and dopamine D1 receptor binding in the suprachiasmatic nuclei.

The effects of maternal melatonin on fetal and neonatal melatonin and dopamine D1 receptor systems in the central nervous system, mainly in the suprachiasmatic nuclei (SCN), were investigated after pinealectomy of rats at day 7 of pregnancy. 125I-labelled iodomelatonin injected intravenously into the pregnant rats (at day 21) was transferred in considerable amount into the fetal circulation. In vitro autoradiography data demonstrated an increase in the melatonin binding activity in the fetal (embryonic day 21) and early postnatal SCN (postnatal day 3) caused by maternal pinealectomy. This upregulation of the melatonin receptor in the SCN was then normalized after the melatonin system of the neonate started to work. The pregnant rats themselves did not show such a change in their melatonin receptors in the SCN following pinealectomy. Dopamine D1 receptor binding was affected by pinealectomy exclusively in the SCN of fetal and neonatal rats as well as in that of mothers. These results clearly indicate that the fetal circadian clock in the SCN is controlled and prepared before birth to some extent by maternal melatonin rhythm.

Animals↗
PubMed1998

Multitissue circadian expression of rat period homolog (rPer2) mRNA is governed by the mammalian circadian clock, the suprachiasmatic nucleus in the brain.

The period (per) gene, controlling circadian rhythms in Drosophila, is expressed throughout the body in a circadian manner. A homolog of Drosophila per was isolated from rat and designated as rPer2. The rPER2 protein showed 39 and 95% amino acid identity with mPER1 and mPER2 (mouse homologs of per) proteins, respectively. A robust circadian fluctuation of rPer2 mRNA expression was discovered not only in the suprachiasmatic nucleus (SCN) of the hypothalamus but also in other tissues including eye, brain, heart, lung, spleen, liver, and kidney. Furthermore, the peripheral circadian expression of rPer2 mRNA was abolished in SCN-lesioned rats that showed behavioral arrhythmicity. These findings suggest that the multitissue circadian expression of rPer2 mRNA was governed by the mammalian brain clock SCN and also suggest that the rPer2 gene was involved in the circadian rhythm of locomotor behavior in mammals.

Amino Acid Sequence↗
PubMed1998

Strategy to sequence the 89 exons of the human LRP1 gene coding for the lipoprotein receptor related protein: identification of one expressed mutation among 48 polymorphisms.

The human lipoprotein receptor related protein (LRP) binds and internalizes a diverse set of ligands, making LRP the most multifunctional endocytic receptor known. This is possible due to the large size, i.e., 600 kDa, of the receptor protein containing three clusters of putative ligand binding domains, each structurally comparable to the classical LDL receptor. Based on previous structural analysis of the human LRP1 gene (Van Leuven et al., 1994, Genomics, 24: 78-89), a strategy was developed to sequence the 89 exons of the LRP1 gene, including partial intron sequences. The gene was amplified from individual genomic DNA by long-range PCR, in 14 amplicons sized between 0.4 and 11 kb that were used as templates for 110 sequencing primers. In total, 48 mutations and intronic polymorphisms were identified. Two previously reported polymorphisms, i.e., in the promoter region and in exon 3, were precisely defined by sequencing. The first expressed mutation, i.e., an alanine to valine transition at position 217 of the LRP precursor protein, was detected on one allele in 2 of 33 individuals. Although the strategy is still subject to refinement, this approach is reported to allow others to analyze genetic differences in the human LRP1 gene, with particular reference to the recently reported association with late-onset Alzheimer disease.

Contig Mapping↗
PubMed1998

Effects of SA6541, a leukotriene A4 hydrolase inhibitor, and indomethacin on carrageenan-induced murine dermatitis.

We investigated the effects of S-(4-dimethylaminobenzyl)-N-[(2S)-3-mercapto-2-methylpropionyl]-L- cysteine (SA6541), a potent leukotriene A4 hydrolase inhibitor. on early phase of carrageenan-induced dermatitis model. Carrageenan injection induced edema and neutrophil influx in the mouse ear. SA6541 inhibited edema formation and neutrophil influx. SA6541 also inhibited leukotriene B4 production but not prostaglandin E2 production in the mouse ear. On the other hand, indomethacin inhibited edema formation but not neutrophil influx. Indomethacin also inhibited prostaglandin E2 production but not leukotriene B4 production. Combination therapy with SA6541 and indomethacin strongly inhibited edema formation in comparison with treatment with either agent alone. These results suggest that leukotriene B4 may be important in the pathogenesis of dermatitis.

Aniline Compounds↗
PubMed1998

Transmission of hepatitis B virus from hepatitis B core antibody-positive donors in living related liver transplants.

BACKGROUND: In order to clarify the risk of hepatitis B virus (HBV) transmission from hepatitis B core antibody-positive (HBcAb(+)) donors and to evolve a new strategy to counter such a risk, we undertook a retrospective (1990-1995) and prospective (1995-1996) analysis of our experience with living related liver transplantation involving HBcAb(+) donors. METHODS: Between June 15, 1990, and June 30, 1995, HBcAb(+) individuals were not excluded as donor candidates at our institutions. For 171 liver transplants, 16 donors were HBcAb(+). Between July 1, 1995, and June 30, 1996, HBcAb(+) individuals were generally excluded as donor candidates; however, three recipients were given liver grafts from HBcAb(+) donors because other donor candidates presented even higher risks. In the latter period, recipients with transplants from HBcAb(+) donors underwent prophylactic passive immunization with hyperimmune hepatitis B immunoglobulin (HBIG). The serum of 10 HBcAb(+) donors was examined by nested polymerase chain reaction for the presence of HBV-DNA, but it was not detected in any of them. However, the same examination of the liver tissue of five such donors yielded positive results in all cases. RESULTS: In the first 5-year period, out of 16 recipients with HBcAb(+) donors, 15 became hepatitis B surface antigen-positive after transplant. The three recipients with HBcAb(+) donors during the second 1-year period, who were treated by prophylactic passive immunization with HBIG, remained hepatitis B surface antigen-negative and negative for serum HBV-DNA after transplant. CONCLUSIONS: HBV exists in the liver of healthy HBcAb(+) individuals, but not in the blood. Therefore, HBV is thought to be transmitted to recipients by liver grafts from the HBcAb(+) donors at a significantly high rate. The prevention of viral activation and clinical disease development by means of passive immunization with HBIG seems promising, although the follow-up period in our study may be too short for any definitive conclusions.

DNA, Viral↗
PubMed1998

Involvement of leukotriene B4 in murine dermatitis models.

Leukotriene B4 (LTB4) is a product of the 5-lipoxygenase pathway of arachidonic acid (AA) metabolism. LTB4 is a potent chemotactic factor for neutrophils and has been postulated to play an important role in a variety of pathological conditions including rheumatoid arthritis, psoriasis, and inflammatory bowel disease. To investigate the role of LTB4 in dermatitis, we used S-(4-dimethylaminobenzyl)-N-[(2S)-3-mercapto-2-methylpropionyl]-L- cysteine (SA6541), a potent leukotriene A4 (LTA4) hydrolase inhibitor. SA6541 inhibited LTB4 production with an IC50 value of 270 nM in vitro. 5-Hydroperoxyeicosatetraenoic acid (5-HPETE) or AA injection induced LTB4 production and neutrophil influx in mouse ear. SA6541 inhibited 5-HPETE- and AA-induced LTB4 production and neutrophil influx in mouse ear when administered orally at a dose of 50 mg/kg. SA6541 also inhibited 5-HPETE-induced prostaglandin E2 (PGE2) production, probably by an indirect effect through the inhibition of LTB4 production. These results suggest that LTB4 may be important in the pathogenesis of dermatitides such as psoriasis.

Aniline Compounds↗
PubMed1998

LDLR Database (second edition): new additions to the database and the software, and results of the first molecular analysis.

Mutations in the LDL receptor gene (LDLR) cause familial hypercholesterolemia (FH), a common autosomal dominant disorder. The LDLR database is a computerized tool that has been developed to provide tools to analyse the numerous mutations that have been identified in the LDLR gene. The second version of the LDLR database contains 140 new entries and the software has been modified to accommodate four new routines. The analysis of the updated data (350 mutations) gives the following informations: (i) 63% of the mutations are missense, and only 20% occur in CpG dinucleotides; (ii) although the mutations are widely distributed throughout the gene, there is an excess of mutations in exons 4 and 9, and a deficit in exons 13 and 15; (iii) the analysis of the distribution of mutations located within the ligand-binding domain shows that 74% of the mutations in this domain affect a conserved amino-acid, and that they are mostly confined in the C-terminal region of the repeats. Conversely, the same analysis in the EGF-like domain shows that 64% of the mutations in this domain affect a non-conserved amino-acid, and, that they are mostly confined in the N-terminal half of the repeats. The database is now accessible on the World Wide Web at http://www.umd.necker.fr

Computer Communication Networks↗
PubMed1998

A novel point mutation in a splice acceptor site of intron 1 of the human low density lipoprotein receptor gene which causes severe hypercholesterolemia: an unexpected absence of exon skipping. Mutations in brief no. 139. Online.

Familial hypercholesterolemia (FH) is a genetic disorder caused by mutations in the low density lipoprotein (LDL)-receptor gene. We found a new mutation in the splice acceptor site of intron 1 of the LDL receptor gene, which is designated as 68-1 G->C according to the nomenclature suggested by Beaudet and Tsui (1993), in a Japanese FH homozygote. She was born from consanguineous marriage and has this mutation as a true homozygous form. Her cultured fibroblasts showed no LDL receptor protein synthesis. This mutation caused activation of a cryptic splice acceptor side in the downstream exon 2, leading to frameshift and appearance of premature in-frame stop codon. The mutation was detected by Dde I restriction enzyme. The identical mutation was not found among 24 patients with homozygous and 120 patients with heterozygous FH. The mutation was very rare among the Japanese population.

Alternative Splicing↗
PubMed1998

Pavlik harness applications for congenital dislocation of the hip. How short can they be made?

We studied the results of different durations of application of the Pavlik harness for congenital dislocation or subluxation of the hip. For this, 110 hips in 106 patients were successfully reduced and examined when 6 years old. Dislocation and subluxation cases were divided into two groups: a long-term (4 months for dislocation and 3 months for subluxation) and a short-term (3 months for the former and 2 months for the latter) group. We compared them by roentgenographic analysis. The association between the long- and short-term groups was tested using statistical analyses. There were no significant differences between them, except for one item in subluxation. Therefore, we can say that the duration of application of the Pavlik harness should be reduced to 3 months for dislocation and 2 months for subluxation.

Braces↗
PubMed1998

Myocardial glucose metabolism in patients with hypertrophic cardiomyopathy: assessment by F-18-FDG PET study.

In an investigation of myocardial metabolic abnormalities in hypertrophic myocardium, the myocardial glucose metabolism was evaluated with F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) in 32 patients with hypertrophic cardiomyopathy, and the results were compared with those in 9 patients with hypertensive heart disease. F-18-FDG PET study was performed in the fasting and glucose-loading states. The myocardial regional %dose uptake was calculated quantitatively. The average regional %dose uptake in the fasting state in the patients with asymmetric septal hypertrophy and dilated-phase hypertrophic cardiomyopathy was significantly higher than that in the patients with hypertensive heart disease (0.75 +/- 0.34%, 0.65 +/- 0.25%, and 0.43 +/- 0.22%/100 g myocardium, respectively). In contrast, the average %dose uptake in the glucose-loading state in the patients with asymmetric septal hypertrophy and dilated-phase hypertrophic cardiomyopathy was not significantly different from that in patients with hypertensive heart disease (1.17 +/- 0.49%, 0.80 +/- 0.44% and 0.99 +/- 0.45%, respectively). The patients with apical hypertrophy had also low %dose uptake in the fasting state (0.38 +/- 0.21%) as in the hypertensive heart disease patients, so that the characteristics of asymmetric septal hypertrophy and dilated-phase hypertrophic cardiomyopathy are considered to be high FDG uptake throughout the myocardium in the fasting state. Patients with apical hypertrophy are considered to belong to other disease categories metabolically. F-18-FDG PET study is useful in the evaluation of the pathophysiologic diagnosis of patients with hypertrophic cardiomyopathy.

Blood Glucose↗