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Biomedical subjects

K Nihei

Publications and source records attributed to K Nihei.

At least 37 records · Page 2Linked to original sources
PubMed1999

Neurological prognosis correlated with variations over time in the number of subependymal nodules in tuberous sclerosis.

In tuberous sclerosis (TS), brain CT reveals subependymal nodules, cortical tubers and white matter lesions. This study is a retrospective analysis of the relationship between the variations over time in the number of subependymal nodules and the clinical course in cases of tuberous sclerosis. Twenty-four children with tuberous sclerosis, who attended the National Children's Hospital as outpatients, were followed by means of brain CT examinations for 7 years and 1 month on average. Cranial MRI was also performed in 22 cases. Brain CT disclosed subependymal nodules already in early infancy. In almost all cases, the number of subependymal nodules gradually increased with age, especially around the frontal horn of the lateral ventricle. The increase stopped at around age 10. The cases with five or more subependymal nodules at the initial or subsequent CT examination ( 17 patients; Group A) exhibited a significantly greater number of cortical tubers than those with less than five (five patients; Group B) and had white matter lesions unlike Group B. In addition, the number of cases with either infantile spasms or mental retardation was significantly higher in Group A than Group B (P < 0.005). In conclusion, the number of ventricular subependymal nodules may allow prediction of the severity of the cerebral dysfunction in TS. Our results suggest that its variation may reflect the degree of the embryologic disorder when neuronal cells grow in the early gestational period.

Adolescent↗
PubMed1999

Single-cell analysis of mitochondrial DNA in patients and a carrier of the tRNA(Leu)(UUR) gene mutation.

We examined heteroplasmy of mutated mitochondrial DNA in single peripheral lymphocytes derived from 4 individuals carrying the nt 3243 A-to-G mutation, including two patients with MELAS, a patient with cardiomyopathy, deafness and diabetes mellitus, and the asymptomatic mother of one of the MELAS patients. In these subjects, all lymphocytes examined were heteroplasmic to different degrees, with a wider range of heteroplasmy evident in the symptomatic patients than in the healthy carrier.

Abnormalities, Multiple↗
PubMed1999

Expression and localization of aquaporins in rat gastrointestinal tract.

A family of water-selective channels, aquaporins (AQP), has been demonstrated in various organs and tissues. However, the localization and expression of the AQP family members in the gastrointestinal tract have not been entirely elucidated. This study aimed to demonstrate the expression and distribution of several types of the AQP family and to speculate on their role in water transport in the rat gastrointestinal tract. By RNase protection assay, expression of AQP1-5 and AQP8 was examined in various portions through the gastrointestinal tract. AQP1 and AQP3 mRNAs were diffusely expressed from esophagus to colon, and their expression was relatively intense in the small intestine and colon. In contrast, AQP4 mRNA was selectively expressed in the stomach and small intestine and AQP8 mRNA in the jejunum and colon. Immunohistochemistry and in situ hybridization demonstrated cellular localization of these AQP in these portions. AQP1 was localized on endothelial cells of lymphatic vessels in the submucosa and lamina propria throughout the gastrointestinal tract. AQP3 was detected on the circumferential plasma membranes of stratified squamous epithelial cells in the esophagus and basolateral membranes of cardiac gland epithelia in the lower stomach and of surface columnar epithelia in the colon. However, AQP3 was not apparently detected in the small intestine. AQP4 was present on the basolateral membrane of the parietal cells in the lower stomach and selectively in the basolateral membranes of deep intestinal gland cells in the small intestine. AQP8 mRNA expression was demonstrated in the absorptive columnar epithelial cells of the jejunum and colon by in situ hybridization. These findings may indicate that water crosses the epithelial layer through these water channels, suggesting a possible role of the transcellular route for water intake or outlet in the gastrointestinal tract.

Animals↗
PubMed1999

The value of serial auditory brainstem response in patients with subacute sclerosing panencephalitis.

A total of 98 serial auditory brainstem responses from 17 patients (11 boys and 6 girls) with subacute sclerosing panencephalitis were compared with their clinical course and stages. These patients were exposed to measles early in life (at 1.8 +/- 1.4 years old) with the average onset of the disease at 8.8 +/- 0.7 years of age. The main abnormalities of their auditory brainstem responses were a prolongation of waves I, III, and V, and of the I to V interpeak interval. Wave V thresholds were also elevated. These effects on the auditory brainstem responses started 1 to 2 years after onset of neurologic signs. I to V interpeak latency became prolonged with the progress of clinical stages, especially in Jabbour's clinically advanced stage IV. In two patients with an acute progressive type of subacute sclerosing panencephalitis, very rapid deterioration with a distorted wave pattern of later components was observed. These findings suggest rostrocaudal progression in the central nervous system of both long-term and fulminant cases.

Acute Disease↗
PubMed1999

Virtual reality in a children's hospital.

We used virtual reality technology to improve the quality of life and amenity of in-patients in a children's hospital. Children in the hospital could enjoy a zoo, amusement park, and aquarium, in virtual. They played soccer, skiing and horse riding in virtual. They could communicate with persons who were out of the hospital and attend the school which they had gone to before entering hospital. They played music with children who had been admitted to other children's hospitals. By using this virtual technology, the quality of life of children who suffered from psychological and physiological stress in the hospital greatly improved. It is not only useful for their QOL but also for the healing of illness. However, these methods are very rare. Our systemic in our children's hospital is the first to be reported in Japan both software and hardware of virtual reality technology to increase the QOL of sick children need further development.

Child↗
PubMed1997

Development of a virtual sand box: an application of virtual environment for psychological treatment.

The sand play technique has often been used in psychological treatments or in the diagnosis of autism patients. In this paper, the prototype application called "virtual sand box" is developed as a virtual environment to support this technique. Experimental results show the advantages of applying virtual reality technology to clinical medicine; particularly with respect to the diagnosis of people with psychological and psychiatrical difficulties such as autism and neurosis. The actual system has been implemented by using a graphics workstation, a wide-view field display, and 3D input devices.

Autistic Disorder↗
PubMed1997

[Subacute sclerosing panencephalitis (SSPE)].

Subacute sclerosing panencephalitis (SSPE) is one of the most important slow virus infection caused by measles virus in human. It have passed over 20 years since measles virus was found in the brain of SSPE patients. However, definite etiological mechanism is still unknown. In Japan, number of SSPE patients are gradually decreasing, but over 5 patients are reported every year. Recently, the age of onset of SSPE became higher, incubation period from measles to SSPE onset became to be more prolonged, and serum measles antibody titers became lower than before. From typical clinical findings, serum and CSF measles antibody titers and periodic complex high voltage slow waves with suppression burst, SSPE is suggested. It is not so difficult to make diagnosis. As the differential diagnosis, epilepsy, brain tumor, metabolic diseases, or psychological disorders are mentioned. Treatment for SSPE is still undetermined. At present, it is thought that combined treatment of oral inosinpranobex (isoprinosine) and intratechal or intraventricular interferon (IFN) administration is the most effective.

Adolescent↗
PubMed1996

[Quality of life of children with chronic neurological diseases: introductory remarks].

Recent advances in medical technology, such as an assisted ventilation, have made a big impact on pediatrics. With such a progress, many children with intractable diseases have survived intact. On the other hand, chronically ill children with handicaps have also been increasing. Some of them have been artificially supported by a respirator to maintain life in a hospital or at home. Under these social conditions, we should establish a system for total care of these children, to promote their quality of lives, in collaboration with medicine, health & welfare, and education.

Child↗
PubMed1995

Fatal reducing body myopathy. Ultrastructural and immunohistochemical observations.

Two female infants who developed normally during infancy began to have progressive muscle hypotonia and weakness from 2 years 10 months and 2 years 3 months of ages, respectively. Both patients had rapidly progressive muscle weakness with death from respiratory failure at 4 years 11 months and 3 years 9 months, respectively. In addition to mild inflammation in their muscle biopsies, the most striking finding was the presence of numerous reducing bodies (RB) in almost all degenerating fibers. By electron microscopy, these bodies consisted of fine granular material, usually located around the degenerating nucleus. These bodies showed no immunohistochemical reaction to antibodies against structural, cytoskeletal and membrane proteins and a histone-specific antibody against nuclei and chromosomes. They were occasionally positively stained with a ubiquitin antibody. Although the origin of these bodies remains unknown, they appeared to be related to active myofibrillar degeneration, probably resulting from primary nuclear degeneration.

Cell Nucleus↗
PubMed1993

Determination of free N-acetylneuraminic acid in human body fluids by high-performance liquid chromatography with fluorimetric detection.

Determinations of both the free and bound form of N-acetyl-neuraminic acid (NANA) in several human body fluids, such as serum, cerebrospinal fluid (CSF), saliva, urine, amniotic fluid, and milk were carried out by HPLC with fluorimetric detection. The method utilized 1,2-diamino-4,5-methylenedioxybenzene dihydrochloride (DMB) as a fluorimetric derivatizing reagent. Free-form NANA was obtained from the body fluids after ultrafiltration with Microcon 10 (YM-10 cellulose membrane, filtration limit M(r) = 10,000, Amicon). The DMB derivative of NANA was separated isocratically by a Nucleosil 5C18 column with a mixture of 0.1 M sodium phosphate buffer (pH 2.0)-methanol (75:25, v/v). A gradient elution system was used for urine analysis. Analysis times were 10-30 min. Recoveries of free NANA by ultrafiltration were satisfactory: 95.66 +/- 1.80% for serum and 97.27 +/- 1.55% for CSF, respectively. The high sensitivity and specificity render this method applicable to all the body fluids tested. Although a physiological role for free NANA has not yet been elucidated, the method presented promises to contribute to the basic understanding of the NANA metabolism.

Adolescent↗
PubMed1993

Involvement of NPY-immunoreactive neurons in the cerebral cortex of amyotrophic lateral sclerosis patients.

We performed a quantitative histochemical study of neuropeptide Y (NPY) immunoreactivity in postmortem human brain to further define patterns of neuronal degeneration in amyotrophic lateral sclerosis (ALS). The density of NPY fibers was decreased in ALS motor cortex but not in other cortical regions or striatum. Although, the density of cortical NPY neurons was unchanged in high grade cases, neurons were shrunken and atrophic with pruned dendrites. NPY neurons are less severely affected than parvalbumin neurons which are severely depleted in ALS cortex. This differential involvement of local circuit neurons suggests that a simple excitotoxic model may not adequately explain patterns of neuronal loss in ALS.

Adult↗
PubMed1993

Patterns of neuronal degeneration in the motor cortex of amyotrophic lateral sclerosis patients.

We examined patterns of neuronal degeneration in the motor cortex of amyotrophic lateral sclerosis (ALS) patients using traditional cell stains and several histochemical markers including neurofilament, parvalbumin, NADPH-diaphorase, ubiquitin, Alz-50 and tau. Three grades of ALS (mild, moderate, severe) were defined based on the extent of Betz cell depletion. Non-phosphorylated neurofilament immunoreactive cortical pyramidal neurons and non-pyramidal parvalbumin local circuit neurons were significantly depleted in all grades of ALS. In contrast, NADPH-diaphorase neurons and Alz-50-positive neurons were quantitatively preserved despite reduced NADPH-diaphorase cellular staining and dendritic pruning. The density of ubiquitin-positive structures in the middle and deep layers of the motor cortex was increased in all cases. Axonal tau immunoreactivity was not altered. These histochemical results suggest that cortical degeneration in ALS is distinctive from other neurodegenerative diseases affecting cerebral cortex. Unlike Huntington's disease, both pyramidal and local cortical neurons are affected in ALS; unlike Alzheimer's disease, alteration of the neuronal cytoskeleton is not prominent. The unique pattern of neuronal degeneration found in ALS motor cortex is consistent with non-N-methyl-D-aspartate glutamate receptor-mediated cytotoxicity.

Adult↗