Search PubMed⌕ Search

Biomedical subjects

T Nakada

Publications and source records attributed to T Nakada.

At least 55 records · Page 3Linked to original sources
PubMed2001

Enzymatic synthesis of kojioligosaccharides using kojibiose phosphorylase.

We have attempted to synthesize kojioligosaccharides (oligosaccharides having the alpha-1,2 glycosidic linkage at the nonreducing end) using two methods. In the first, mixtures of various proportions of glucose and beta-D-glucose-1-phosphate (beta-G1P) were allowed to react in the presence of kojibiose phosphorylase (KPase). In the second, maltose was allowed to react with KPase and maltose phosphorylase (MPase) simultaneously. In the former method, kojioligosaccharides having only the alpha-1,2 glucosidic linkage were synthesized and the average degree of polymerization (D.P.) of oligosaccharides increased with decreasing proportions of glucose. In the second method, kojioligosaccharides were obtained at approximately 70% yields under optimum conditions. 4-alpha-D-Kojibiosyl-glucose, kojitriose and kojitetraose, the principal kojioligosaccharides synthesized, were not hydrolyzed by salivary amylase, artificial gastric juice, pancreatic amylase, or small intestinal enzymes.

Journal Article↗
PubMed2001

High-field magnetic resonance imaging in patients with moyamoya disease.

OBJECT: The purpose of this study was to assess the utility of high-field magnetic resonance (MR) imaging as a quantitative tool for estimating cerebral circulation in patients with moyamoya disease. METHODS: Eighteen patients with moyamoya disease who were scheduled to undergo revascularization surgery and 100 healthy volunteers were examined using T2-reversed MR imaging performed using a 3-tesla system. Ten of the 18 patients underwent a second study between 1 year and 3 years after revascularization. Magnetic resonance images obtained in the patients with moyamoya disease were statistically analyzed and compared with those obtained in healthy volunteers. The MR imaging findings were also correlated with results of single-photon emission computerized tomography and conventional cerebral angiography studies. Transverse lines in the white matter (medullary streaks) were observed in almost all persons. In healthy volunteers, the diameter sizes of the medullary streaks increased significantly with age (p < 0.001). Multiple logistic regression analysis revealed that age-adjusted medullary streak diameters were significantly larger in patients with moyamoya disease (p < 0.001). Diameter sizes also increased significantly with the increased severity of cerebral hypoperfusion (p < 0.001) and a higher angiographically determined stage of the disease (p < 0.001). Diameter sizes decreased significantly after surgery (p < 0.001). CONCLUSIONS: The increases in medullary streak diameters observed in patients with moyamoya disease appear to represent vessels dilated due to cerebral hypoperfusion. High-field T2-reversed MR imaging is useful in estimating cerebral circulation in patients with moyamoya disease.

Adolescent↗
PubMed2001

Molecular cloning and characterization of a 21 kDa protein secreted from Trichinella pseudospiralis.

Recombinant protein was produced from the cDNA library of Trichinella pseudospiralis, which seemed to form part of the excretory-secretory (ES) products. The library was constructed from cDNA of muscle larvae at 1 month post-infection, and immunoscreened with antibody against T. pseudospiralis ES products. A clone, designated Tp21-3, contained a cDNA transcript of 657 bp in length with a single open reading frame, which encoded 172 amino acids (19617 Da in the estimated molecular mass). The predicted amino acid sequence of clone Tp21-3 had a similarity of 76% to that of clone ORF 17.20 (GenBank under accession number U88239) from T. spiralis. The recombinant fusion proteins encoded by clone Tp21-3 were produced in an Escherichia coli expression system and affinity purified. On Western blotting analysis, Tp21-3 recombinant proteins migrated at 40 kDa and reacted to antibody against T. pseudospiralis ES products and T. pseudospiralis-infected sera. Sera were developed against Tp 21-3 recombinant proteins, which reacted to a single band migrating at 21 kDa in crude worm extract and ES products from T. pseudospiralis on Western blotting analysis, and reacted with stichocytes of T. pseudospiralis on immunohistochemical staining.

Animals↗
PubMed2001

Central tinnitus: a case report.

We report a case of acute-onset unilateral tinnitus in a 25-year-old woman. Analysis of imaging studies indicated that the tinnitus was likely caused by an acute hemorrhage of a small cavernous angioma that was located adjacent to the contralateral primary auditory cortex. This case provides substantial support for the concept that central tinnitus might indeed represent a pathologic activation of neural networks of nonspecific auditory perception.

Adult↗
PubMed2001

[Recent advancements in MR functional analysis].

Recent advancements in magnetic resonance (MR) technology have revolutionized not only structural but also functional imaging. It is now possible to perform detailed analysis of all aspects of brain function non-invasively. From the neurological standpoint, analysis of gray matter can be categorized into (1) functional mapping and (2) neuron density measurement. Similarly, analysis of white matter can be categorized into (1) tract mapping and (2) axonal physiology. Corresponding techniques in MR imaging are functional MRI (fMRI), MR neuronography (MRN), MR tractography (MRT), and MR axonography (MRX). While fMRI is a T2* contrast based technique, the rest of the techniques are based on diffusion tensor analysis (DTA).

Brain↗
PubMed2000

DNA fingerprints of Trichinella as revealed by restriction fragment length polymorphism and single-strand conformational polymorphism (RFLP-SSCP).

A method was developed for gene fingerprinting, combining the principles of restriction fragment length polymorphism and single-strand conformational polymorphism (PCR-RFLP-SSCP). Taking advantage of this method, we analysed the genotypes of 20 isolates from five species of Trichinella (Trichinella spiralis, Trichinella britovi, Trichinella nativa, Trichinella murrelli and Trichinella pseudospiralis) and two uncertain genotypes (Trichinella T6 and Trichinella T8). Target genes for the analysis included three kinds of random amplified polymorphic DNA (RAPD), the gene encoding 43 kDa excretory-secretory protein, the gene encoding mitochondrial cytochrome c -oxidase subunit I and the gene of 18 S rRNA. The genotype revealed by this method was in good concordance with the taxonomy of Trichinella (six species and two uncertain genotypes which is currently accepted based on morphology, isozyme pattern and reproductive isolation). More important, this method revealed intraspecies polymorphism among geographical isolates of T. spiralis and T. britovi.

Animals↗
PubMed2000

Milder childhood form of very long-chain acyl-CoA dehydrogenase deficiency in a 6-year-old Japanese boy.

UNLABELLED: We investigated the clinical and biochemical characteristics of a 6-year-old Japanese boy with very-long-chain acyl-CoA dehydrogenase (VLCAD) deficiency. He had hypoketotic hypoglycaemia, exercise- and fasting-induced lethargy, hepatomegaly and cardiomegaly. Significant laboratory findings included elevated plasma levels of creatine phosphokinase and acyl-carnitine and a fatty liver at biopsy suggesting a diagnosis of VLCAD deficiency. CONCLUSION: The diagnosis of very long-chain acyl-CoA dehydrogenase deficiency was supported by the results of acyl-CoA dehydrogenase activity for C8 and C16 fatty acids in skin fibroblasts from the patient. Treatment with medium chain triglycerides and L-carnitine in the diet improved his hepatomegaly and cardiomegaly.

Acyl-CoA Dehydrogenase, Long-Chain↗
PubMed2000

Morphometric analysis of symptomatic benign prostatic hyperplasia with and without bladder outlet obstruction.

To investigate the histological features of benign prostatic hyperplasia (BPH) with and without bladder outlet obstruction (BOO), 32 patients with symptomatic BPH, 22 with BOO and ten without BOO, were studied. The area density of smooth muscle, fibrous tissue, glandular epithelium, and glandular lumen in BPH adenoma resected by transurethral surgery was estimated using morphometric analysis. No differences were found in the area density of stromal and glandular components between the two groups. In the glandular component, neither the epithelium nor lumen differed between the two groups. However, the area density of smooth muscle in the obstructed group showed a decrease compared to that in the unobstructed group (P < 0.01). We conclude that a decreased proportion of smooth muscle in BPH adenoma may play an important role in BOO.

Aged↗
PubMed2000

Independent component-cross correlation-sequential epoch (ICS) analysis of high field fMRI time series: direct visualization of dual representation of the primary motor cortex in human.

A new technique for functional magnetic resonance imaging (fMRI) time series analysis is presented. The technique referred to here as independent component-cross correlation-sequential epoch (ICS) analysis is a hybrid technique of two standard methodologies of biological signal analysis, namely, data driven methods, represented by independent component analysis, and hypothesis driven methods, represented by a general linear model. The technique successfully identified four functionally discrete areas within the primary sensorimotor cortex (SMI) in normal human subjects based on blood oxygenation level dependent (BOLD) contrast functional magnetic resonance imaging (fMRI) time series performed on a high field (3.0 T) system. Each of the four areas identified corresponded to the four physiological subdivisions of SMI, recognized in primates to be essential for voluntary hand motion, namely, 4 anterior (MI-4a) and 4 posterior (MI-4p) of the primary motor cortex, and 3a and the 'classical' (Brodmann areas 1, 2, and 3b) primary sensory cortex, respectively. ICS analysis appears to be a highly reliable and versatile technique for fMRI time series analysis.

Algorithms↗
PubMed2000

Use tests: ROAT (repeated open application test)/PUT (provocative use test): an overview.

As one step in defining the clinical relevance of exposure to an allergen identified with patch testing, use tests (provocative use test (PUT), and repeated open application test (ROAT)) have been used. In 1/2 of the cases of seemingly reliable patch tests, use tests are negative, suggesting that the patient's biologic threshold of response had not been reached with open application dosing. Dramatic differences exist in regional skin reactivity and percutaneous penetration. Negative results of use tests on normal skin may become positive on diseased skin. To refine this assay further, more controlled observations and analysis of reaction differences between normal and damaged skin, and among regional anatomic sites might be performed. In addition, we require a standardized measurement for the results. Use testing has significant potential in refinement of the evidence-based diagnosis of clinical relevance. However, for general validation, we should fill the deficiencies described above.

Animals↗
PubMed2000

Indication of cystoscopy in patients with asymptomatic microscopic haematuria.

To establish the appropriate indication of cystoscopy in patients with asymptomatic microscopic haematuria, we reviewed 263 cases with positive reaction for urinary dipstick test on annual health screening examination. On initial examination, 18 highly significant lesions, 52 moderately significant lesions and 38 insignificant lesions were detected. No underlying lesion could be found in 96 patients and no microscopic haematuria in 59 patients. However, bladder cancers were detected in only 8 (3.0%) cases. All patients with bladder cancer were older than 40 years. These facts suggest that cystoscopy is not necessary for patients with a single microscopic haematuria and those younger than 40 years.

Adolescent↗
PubMed2000

Posterior retroperitoneoscopic partial adrenalectomy using ultrasonic scalpel for aldosterone-producing adenoma.

BACKGROUND: Posterior retroperitoneoscopic adrenalectomy has become a standard procedure, but removal of the entire gland is not necessary in all cases. PATIENTS AND METHODS: We performed 10 posterior retroperitoneoscopic partial adrenalectomies for aldosterone-producing adenoma (APA) using an ultrasonic scalpel to divide the normal adrenal gland and the adenoma. RESULTS: The mean operation time and blood loss were 154 (110-231) minutes and 11 (5-32) mL, respectively. The mean weight of removed tissue was 5.7 g (2.3-10.2 g). Subcutaneous emphysema occurred in three patients, but there were no serious operative complications. CONCLUSION: Posterior retroperitoneoscopic partial adrenalectomy using the ultrasonic scalpel may be a valuable treatment for typical solitary APA.

Adenoma↗
PubMed2000

Apoptosis of testicular germ cells induced by exogenous glucocorticoid in rats.

The influence of exogenous glucocorticoid, dexamethasone (Dex), on testicular germ cell apoptosis was investigated in rats. The percentages of apoptotic tubules and apoptotic germ cells in the Dex-treated group of rats were about seven-fold and 10-fold higher respectively than in either the control group, or in rats treated with glucocorticoid receptor agonist (GR-A), or in rats treated with both Dex and GR-A. These results suggest that, in rats, apoptosis of testicular germ cells is mediated by glucocorticoid receptors.

Animals↗
PubMed2000

CAG repeat length of the androgen receptor gene in Japanese males with cryptorchidism.

We have analysed the CAG repeat length in exon 1 of the androgen receptor gene in 48 Japanese males with cryptorchidism and 100 fertile Japanese males. The CAG repeat length was 23.4 +/- 0.48 (mean +/- SE) (range 16-32, median 23) in cryptorchid patients and 23.5 +/- 0.29 (range 15-32, median 23) in normal males. There was no significant difference between the two groups. The expansion of the CAG repeats in exon 1 of the androgen receptor gene is unlikely to constitute a major cause of cryptorchidism.

Adolescent↗
PubMed2000

Area density of smooth muscle cells and response to endothelin 1 in human hyperplastic prostate.

BACKGROUND: alpha-Agonists and endothelins (ETs) are the only agents that have been proved to induce significant contraction of the prostate. Although the response to phenylephrine (PE) is dependent on the quality of smooth muscle (SM) within the prostate, it is not clear whether the response to ET-1 is also influenced by SM density. We evaluate the relationship between contractile responsiveness to ET-1 and the area density of SM of the human prostate. MATERIALS AND METHODS: Specimens were obtained from 17 patients with prostatic hyperplasia that underwent transurethral resection of the prostate. Specimens were used for isometric tension study (PE, KCl and ET) and also for quantitative morphometric analysis. RESULTS: PE and ET-1 induced dose-dependent contractile responses. There were no significant differences in the average maximum response (E(max)) to these two agents. E(max) to KCl and PE showed direct positive correlations with the area density of SM. E(max) to ET-1 also showed a positive correlation with the SM density, although this relationship was weaker than those for the other two agents. Moreover, there was a strong positive relationship between E(max) to PE, KCl and that to ET-1. CONCLUSIONS: The area density of SM appeared to significantly influence the contractile response to ET-1 as well as the response to PE and KCl.

Aged↗