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Biomedical subjects

R Nakamura

Publications and source records attributed to R Nakamura.

At least 73 records · Page 4Linked to original sources
PubMed2000

Neurological abnormalities in cognitively impaired but not demented elderly.

OBJECTIVE: We determined the prevalence and clinical characteristics of elderly people with cognitively impaired but not demented (CIND) in the community. MATERIAL AND METHODS: We examined 945 elderly residents (aged 65 years or more) in a cross-sectional study of a standardized clinical examination in 27 randomly selected communities in the town of Mifune, a standard farming town in Japan. RESULTS: The prevalence of CIND and dementia were 10.8% and 4.8%, respectively, with both rates increasing with age. The frequency of most neurological signs in CIND elderly was greater than that found in subjects with no cognitive impairment (NCI) and less than that in subjects with dementia. The mean ADL disability score in CIND subjects also lay between the mean values for those with NCI and those with dementia. There were no differences in lifestyles between the CIND group and the other groups. CONCLUSION: The results suggest that a majority of CIND elderly suffer from brain dysfunction due to chronic neurological disorders or aging itself.

Activities of Daily Living↗
PubMed2000

Molecular bases of congenital hypopigmentary disorders in humans and oculocutaneous albinism 1 in Japan.

The molecular bases of various types of congenital hypopigmentary disorders have been clarified in the past 10 years. Homozygous gene mutations of enzymes functional in melanogenesis such as tyrosinase, P protein and DHICA oxidase, result in oculocutaneous albinism (OCA) 1, OCA 2, and OCA 3, respectively. The genes responsible for Hermansky-Pudlak syndrome (HPS) and Chediak-Higashi syndrome (CHS) have also recently been isolated and cloned. The transcription factor paired box 3 (PAX3) works at the promoter region of the microphthalmia-associated transcription factor (MITF) gene, and the MITF transcription factor orders the expression of c-kit, which encodes the receptor for stem-cell factor, which in turn stimulates melanoblast migration from the neural tube to the skin in the embryo. Heterozygous mutations of PAX3, MITF, or c-kit genes induce Waardenburg syndrome (WS) 1/3, WS 2 or Piebaldism, respectively. A defect of endothelin-3 or the endothelin-B receptor produces WS 4. In our examination of 26 OCA 1 patients in Japan, all were found to have homozygous or heterozygous tyrosinase gene mutations at codons 77 or 310. Therefore, mutations at codons 77 and 310 are the major ones in Japanese patients with OCA 1. An autosomal dominant pigmentary disease of dyschromatosis symmetrica hereditaria (DSH) is well known in Japan, and is characterized by a mixture of hypo- and hyper-pigmented macules of various sizes on the backs of the hands and feet. The disease gene and its chromosomal localization have not been identified yet. Our trial of linkage analysis and positional cloning to determine the disease gene is presented.

Albinism, Oculocutaneous↗
PubMed2000

Distraction lengthening of the forearm for congenital and developmental problems.

Thirty-five callus distractions of the forearm were carried out in 23 patients, who were divided into two groups according to the cause of the shortening. Eleven cases in group A had congenital dysplasia, and the 12 cases in group B had growth disturbances from tumours or infection. The mean amount of lengthening was 27 mm in group A and 25 mm in group B. The mean percentage increase in length was 35% and 17%, respectively. The mean duration of fixation was 159 days and 127 days, respectively. The Healing Index had a positive correlation with the age at surgery in group A, but not in group B. The main complication was callus deformity after the removal of a fixator, which was especially frequent in group A. To avoid complications, the aetiology of shortening and the age of the patient should be considered when deciding the surgical protocol.

Adolescent↗
PubMed2000

Does high-resolution MR imaging have better accuracy than standard MR imaging for evaluation of the triangular fibrocartilage complex?

We compared the findings of high-resolution MR imaging and standard MR imaging in the detection of tears of the triangular fibrocartilage in 33 patients with chronic wrist pain on the ulnar side. With arthroscopy as the standard of reference, sensitivity was 100%, specificity 53%, and accuracy 79% with the high-resolution MR imaging, against 83%, 67%, and 76% with the standard MR imaging. High-resolution MR imaging showed a higher sensitivity, but a decreased specificity in the assessment of the triangular fibrocartilage. The results showed that diagnosis of tears in the triangular fibrocartilage by MR imaging, even high-resolution MR imaging, is unsatisfactory, although further technological advances may well improve the accuracy.

Adult↗
PubMed2000

Diagnostic imaging for fracture of the hook of the hamate.

We experienced 16 patients with a fracture of the hook of the hamate. The routine posteroanterior view raised the suspicion of fracture in four of 13 patients (31%), the carpal tunnel view showed the actual fractures in six of 14 patients (43%), and the supine oblique radiographic view of the wrist showed fractures in eight of ten patients (80%). Computed tomography corroborated the fracture in all eight patients (100%). Computerized tomography proved most useful for accurate diagnosis of fracture of the hook of the hamate.

Adult↗
PubMed2000

Decrease in rice allergenic proteins of polished rice grains by incubating with a miso solution.

The effect of miso on allergenic proteins in rice seeds was investigated. When polished rice grains were incubated at 37 degrees C for 30-120 min with a 10% miso solution, but not with heat-treated miso or 1% NaCl, the amount of soluble proteins extracted from the rice grains with 1 M NaCl markedly decreased. SDS-PAGE, immunoblotting and densitometric analyses of these soluble proteins and insoluble proteins indicate that 26 kDa globulin and 14-16 kDa allergens in the grains were decreased to 15-60% during incubation with the miso solution, especially soybean-koji miso, without any large change in the content of major insoluble proteins.

Allergens↗
PubMed2000

Retrospective study of factors affecting employability of individuals with cerebral palsy in Japan.

The purpose of this study was to investigate the characteristics of individuals with cerebral palsy that affected their ability to find a job in Japan. A retrospective nonrandomized descriptive study was performed. Subjects were 99 individuals with cerebral palsy who were eligible to have a vocational training at the National Rehabilitation Center for the Disabled after graduation from high school. All of them were able to perform ADL unassistedly. The mean age of the subjects was 19.9 years (range, 18 to 33) and the mean intelligence quotient measured by WAIS-R was 78.5 (range, 46 to 110). Walking ability, being female and experience of learning in a regular middle high school were significant explanatory variables in the multiple regression equation. The ability of individuals with cerebral palsy to get a job in Japan in the 1990's was largely determined by being able to walk and having an education in a regular school.

Adolescent↗
PubMed2000

[Intranet-based integrated information system of radiotherapy-related images and diagnostic reports].

PURPOSE: To use an intranet technique to develop an information system that simultaneously supports both diagnostic reports and radiotherapy planning images. METHODS: Using a file server as the gateway a radiation oncology LAN was connected to an already operative RIS LAN. Dose-distribution images were saved in tagged-image-file format by way of a screen dump to the file server. X-ray simulator images and portal images were saved in encapsulated postscript format in the file server and automatically converted to portable document format. The files on the file server were automatically registered to the Web server by the search engine and were available for searching and browsing using the Web browser. RESULTS: It took less than a minute to register planning images. For clients, searching and browsing the file took less than 3 seconds. Over 150,000 reports and 4,000 images from a six-month period were accessible. Because the intranet technique was used, construction and maintenance was completed without specialty. CONCLUSION: Prompt access to essential information about radiotherapy has been made possible by this system. It promotes public access to radiotherapy planning that may improve the quality of treatment.

Computer Communication Networks↗
PubMed2000

[Reduced signal intensity of T2 weighted MR imaging of thalamus and putamen in multiple sclerosis in Japan].

Although studies using magnetic resonance imaging (MRI) in multiple sclerosis (MS) patients have focused on findings in the white matter because of its demyelination pathogenesis, Drayer et al. have reported a high incidence of low signal intensity on T2 weighted MR imaging (MRI) in gray matter such as the thalamus and putamen. In Japan there has been no investigation of MRI findings of the basal ganglia in MS patients. Therefore, we attempted to examine the incidence and clinical significance of the imaging phenomenon in 34 Japanese patients with MS (12 male, 22 female, ages 18-54 years). As it is well known that the spinal cord and optic nerves are more frequently involved in MS than the brain in Japanese patients, we divided the patients into two subgroups based on their clinical features and the major sites of demyelination on MRI. One group included the 17 patients whose demyelinations occurred in the brain (brain-type), and the other group included the 17 patients whose abnormalities were found in the spinal cord with or without optic nerve involvement (non-brain type). As a control, MRI studies were also performed in age-matched patients with headache without any neurological signs. On T2 weighted MRI, decreased signal intensity in the thalamus was found in only four patients with MS, 11.8% of the total number examined, and in the putamen in three patients with MS, 8.8% of the total examined. All of the patients who showed abnormal decreased signal intensity in the thalamus and/or putamen belonged to the brain-type group, and these incidences were 23.5% in the thalamus and 17.6% in the putamen among the brain-type patients. No patient belonging to the non-brain type showed this imaging sign. This imaging sign was well correlated with the degree of white matter abnormalities in the brain estimated as a score according to modified Callanan et al.'s method. In addition, this sign was also correlated with the expanded disability status scales (EDSS) in the brain-type patients. These observations suggest that the axonal damages due to severe demyelination may induce the impaired transport of iron resulting in an accumulation of ferritin in the thalamus and putamen, and would cause decreased signal intensity on T2 weighted MRI. The relatively low incidence of decreased signal intensity in the thalamus and putamen in this study may be associated with differences in the clinical phenotype of MS between Japan and the USA. In brain-type patients the evaluation of basal ganglia on T2 weighted MRI may be a useful tool for estimating patients' disabilities.

Adolescent↗
PubMed1999

Atomic force microscopy to study the degranulation in rat peritoneal mast cells after activation.

We have studied the degranulation in rat peritoneal mast cells by atomic force microscopy (AFM). Although AFM has advantages close to electron microscopy (EM) in spatial resolution, visualization of surface topography in peritoneal mast cells has not been reported yet. In the present paper we have succeeded in visualizing the degranulation process of rat peritoneal mast cells by AFM. AFM images showed that secretory granules were about 1 microm in diameter and that they were densely packed in the cytoplasm surrounding the nucleus. After stimulation with compound 48/80 (5 microg/ml), the packed granules began to loosen through formation of irregular cracks, as if polymerization of actin filaments was changed; 3 min after stimulation with compound 48/80 at 37 degrees C, the packed granules were completely loosened and the nucleus was no longer covered by the granules. In addition, AFM images showed clear fringes at the edges of the spreading cells. The fringes were 30-50 nm in height and there existed many small matrixes which were secreted to the outside of the cell. The matrixes were about 80 nm in diameter and 40 nm in height. These kinds of secretory matrixes were observed here first by AFM.

Animals↗
PubMed1999

Familial paroxysmal dystonic choreoathetosis: clinical findings in a large Japanese family and genetic linkage to 2q.

BACKGROUND: Paroxysmal dystonic choreoathetosis (PDC) is a rare familial movement disorder that has been mapped to chromosome 2q31-36. OBJECTIVE: To study the first Japanese family with PDC clinically and genetically. PATIENTS AND METHODS: We studied a large Japanese family in which at least 17 members in 6 generations have been affected by PDC. We interviewed and examined 26 family members, 8 of whom revealed choreoathetosis-like and dystonialike involuntary movement and 1 of whom revealed no involuntary movement but only muscle stiffness such as the aura of paroxysmal dystonic choreoathetosis (PDC). Genetic linkage studies of this family were carried out with polymorphic DNA markers. RESULTS: The attacks of involuntary movement or muscle stiffness were precipitated by ovulation, menstruation, emotional stress, or caffeine or alcohol ingestion. Magnetic resonance imaging of the brain revealed no abnormalities. Clonazepam therapy was effective for reducing the attacks, and ingestion of garlic was believed by patients to be effective for softening the attacks. An affected woman with only muscle stiffness showed remission after hysterectomy for hysteromyoma. This woman also had the disease haplotype and transferred it to her typical PDC-affected daughter. Maximal pairwise logarithm of odds scores exceeding 2.00 were obtained at D2S2250, D2S1242, D2S377, D2S2148, and D2S126. The PDC gene was demonstrated by linkage analyses to be located in a 15.3-centimorgan interval lying between D2S371 and D2S339 based on pairwise and multipoint logarithm of odds scores and obligate recombination events in affected individuals. CONCLUSIONS: Linkage of PDC to chromosome 2q32-36 was confirmed in a Japanese family. The clinical characterizations of this family with PDC include that ovulation seems also to be a precipitating factor of the attacks and that hysterectomy seems to be effective for softening the attacks. Although low-dose clonazepam treatment was most effective, garlic use was believed by affected members to be effective for softening the attacks. Furthermore, based on the results of clinical and genetic analyses, we suggest that muscle stiffness without involuntary movement may represent a forme fruste of PDC.

Athetosis↗
PubMed1999

Problems in neoadjuvant chemoradiotherapy preceding surgery for advanced squamous cell carcinoma of the thoracic esophagus.

The adverse effect of neoadjuvant chemoradiotherapy on the postoperative course in esophageal cancer was studied in 9 patients undergoing neoadjuvant chemoradiotherapy preceding surgery for thoracic esophageal carcinoma possibly involving adjacent organs (neoadjuvant group), and 13 patients undergoing surgery without neoadjuvant therapy for same disease (control group). The two groups were compared for volume of intraoperative hemorrhage, surgical duration, frequency of postoperative morbidity, and for postoperative changes in blood platelet counts, and serum thrombopoietin and interleukin-6 levels. Mean intraoperative blood loss was 1121 g (580-1,662 g) in the neoadjuvant group and 546.5 g (274.7-778.3 g) in controls group (Student's T test: p < 0.01). No significant difference was seen found between the two groups in the degree of postoperative deterioration in cardiopulmonary function or in interleukin-6 levels. Blood platelet counts decreased in both groups until postoperative day 7, but recovery on postoperative day 14 was significantly depressed in the neoadjuvant group compared to controls. Serum thrombopoietin levels were higher in the neoadjuvant group than in controls (Mann-Whitney U-test: p < 0.05). We found that neoadjuvant chemoradiotherapy induces latent postoperative myelosuppression and may lead to intractable infection.

Aged↗
PubMed1999

An immunohistochemical study of Purkinje cells in a case of hereditary cerebellar cortical atrophy.

We report an immunohistochemical study of Purkinje cells located in the molecular layer (ectopic Purkinje cells) and in the Purkinje cell layer (orthotopic Purkinje cells) of a patient who died young and had been diagnosed with hereditary cerebellar cortical atrophy from both clinical and neuropathological findings. All the ectopic and orthotopic Purkinje cells were immunoreactive with an anti-calbindin-D antibody, confirming that these stained cells were Purkinje cells. The perikarya of some ectopic and orthotopic Purkinje cells were stained by an antibody to phosphorylated neurofilament. In contrast, Purkinje cells of three normal controls did not react with this antibody. This finding of an abnormal accumulation of phosphorylated neurofilaments in the perikarya may be due to abnormal phosphorylation. Moreover, the regions around the cell bodies of some ectopic and orthotopic Purkinje cells were intensely immunoreactive with an antibody to synaptophysin, which suggests an abnormal increase in presynaptic terminals. It is suggested that ectopia of Purkinje cells, accumulation of phosphorylated neurofilament in the perikarya and an abnormal increase in presynaptic terminals around the soma of the Purkinje cells may be relevant to the pathophysiology of Purkinje cell degeneration in this case. In addition, the relationship between phosphorylated neurofilament and synaptophysin reactivity is discussed.

Adult↗
PubMed1999

Positive inotropic effect of insulin-like growth factor-1 on normal and failing cardiac myocytes.

OBJECTIVE: The acute administration of growth hormone (GH) or insulin-like growth factor-1 (IGF-1) improves cardiac performance, possibly contributing to the beneficial effects of GH therapy on heart failure (HF). GH can induce the production of IGF-1 and thus the actions of GH may be mediated through its IGF-1 induction. However, these effects have not yet been demonstrated in failing hearts and the cellular basis of GH or IGF-1-induced inotropic effects remains unknown. We examined the direct effects of GH and IGF-1 on the contractile function and intracellular calcium ([Ca2+]i) homeostasis in normal and failing myocytes. METHODS: To determine whether GH and IGF-1 have a direct effect on myocardial contractility and whether the GH/IGF-1-induced effect was the results of changes in Ca2+ activation, cell shortening and [Ca2+]i transient were simultaneously measured in the left ventricular myocyte preparations, isolated from normal and rapid pacing-induced HF dogs. RESULTS: Basal shortening of HF myocytes was reduced by 64% (p < 0.01). In normal and HF myocytes, GH (0.4-40 x 10(-3) IU/ml) had no effect on either cell shortening or [Ca2+]i transients. In normal myocytes, IGF-1 exerted a positive inotropic effect in a time- and dose-dependent manner (25-500 ng/ml), associated with a parallel increase of [Ca2+]i transient amplitude. IGF-1 increased the shortening magnitude in normal (121 +/- 5% increase from baseline, p < 0.05) and HF (118 +/- 4% increase from baseline, p < 0.05) myocytes. It also increased [Ca2+]i transient amplitude in normal and HF cells by 124 +/- 4 and 125 +/- 7%, respectively. The percent increase of cell shortening and [Ca2+]i transient amplitude was comparable between normal and HF myocytes. Furthermore, IGF-1 did not shift the trajectory of the relaxation phase in the phase-plane plots of cell length vs. [Ca2+]i, indicating that it did not change myofilament Ca2+ sensitivity. CONCLUSIONS: In both normal and HF conditions, IGF-1 exerted an acute direct positive inotropic effect in adult cardiac myocytes by increasing the availability of [Ca2+]i to the myofilaments, possibly explaining the beneficial effect of GH on HF.

Actin Cytoskeleton↗
PubMed1999

Expression characteristics of CS-ACS1, CS-ACS2 and CS-ACS3, three members of the 1-aminocyclopropane-1-carboxylate synthase gene family in cucumber (Cucumis sativus L.) fruit under carbon dioxide stress.

We investigated the expression pattern of three 1-aminocyclopropane-1-carboxylate (ACC) synthase genes, CS-ACS1, CS-ACS2 and CS-ACS3 in cucumber (Cucumis sativus L.) fruit under CO2 stress. CO2 stress-induced ethylene production paralleled the accumulation of only CS-ACS1 transcripts which disappeared upon withdrawal of CO2. Cycloheximide inhibited the CO2 stress-induced ethylene production but superinduced the accumulation of CS-ACS1 transcript. At higher concentrations, cycloheximide also induced the accumulation of CS-ACS2 and CS-ACS3 transcripts. In the presence of CO2 and cycloheximide, the accumulation of CS-ACS2 transcript occurred within 1 h, disappeared after 3 h and increased greatly upon withdrawal of CO2. Inhibitors of protein kinase and types 1 and 2A protein phosphatases which inhibited and stimulated, respectively, CO2 stress-induced ethylene production had little effect on the expression of these genes. The results presented here identify CS-ACS1 as the main ACC synthase gene responsible for the increased ethylene biosynthesis in cucumber fruit under CO2 stress and suggest that this gene is a primary response gene and its expression is under negative control since it is expressed by treatment with cycloheximide. The results further suggest that the regulation of CO2 stress-induced ethylene biosynthesis by reversible protein phosphorylation does not result from enhanced ACC synthase transcription.

Base Sequence↗