Search PubMed⌕ Search

Biomedical subjects

Y Arai

Publications and source records attributed to Y Arai.

At least 163 records · Page 9Linked to original sources
PubMed2000

Diagnostic imaging with newly developed ortho cubic super-high resolution computed tomography (Ortho-CT).

OBJECTIVE: Ortho cubic super-high resolution computed tomography (Ortho-CT), which we have developed, is characterized by the small size of the unit and the ability to produce 3-dimensional images of high resolution with low-radiation doses. The purpose of this study was to investigate the clinical usefulness of Ortho-CT for the diagnosis of diseases in the oral and maxillofacial region. STUDY DESIGN: Ortho-CT has been used for the imaging diagnosis of a radicular cyst of the upper first molar, mesiodense, tooth fractures in the upper anterior region, a fracture of the condylar process, or presurgical evaluation for a dental implant. The usefulness of 3-dimensional images obtained by Ortho-CT was investigated in this study. RESULTS: Ortho-CT produced images of high resolution, enabling identification of the extent of the lesions and the fracture line, the condition of the impacted tooth, and the relationship with the maxillary sinus, mandibular canal, and adjacent teeth. CONCLUSION: Because Ortho-CT can take high-resolution 3-dimensional images at any tomographic layer with only 1 exposure, it is useful for the diagnosis of diseases in the oral and maxillofacial region.

Adult↗
PubMed2000

Analysis of the flow patterns of liquid organic compounds between blade electrodes by classification models

The flow patterns of 20 organic liquids with diverse structures and functionalities between electrodes were measured under a dc electric field. The results clearly showed the existence of a strong relationship between the flow pattern of a compound and its molecular structure. On the basis of a variety of 23 molecular descriptors including those obtained by quantum-chemical calculations, multiple regression analysis and discriminant analysis were applied to identify the significant factors contributing to the flow patterns. For the flow rate dipole moment, nucleophilic delocalizability and lipophilicity as expressed by the 1-octanol/water partition coefficient were found to be the key factors as judged by a five-value regression model with a squared correlation coefficient (r2) of 0.881. For the direction of the flow, just two quantum-chemical parameters, namely, absolute hardness and the self-polarizability normalized by molecular volume, were identified as significant factors by using linear discriminant analysis. The numbers of misclassified compounds were only one and two for training and prediction (leave-one-out cross-validation), respectively, by the best discriminant model.

Journal Article↗
PubMed2000

Cytomegalovirus infection of the central nervous system stem cells from mouse embryo: a model for developmental brain disorders induced by cytomegalovirus.

Cytomegalovirus (CMV) is the most frequent infectious cause of developmental disorders of the central nervous system (CNS) in humans. Infection of the CNS stem cells seems to be primarily responsible for the generation of the brain abnormalities. In this study, we evaluated the infectivity of murine CMV (MCMV) in epidermal growth factor (EGF)-responsive CNS stem cells prepared from fetal mouse brains, and studied the effect of infection on growth and differentiation of the stem cells. The CNS stem cells were permissive for MCMV infection, although MCMV replication was slower than in mouse embryonic fibroblasts. MCMV infection inhibited the growth and DNA replication of the stem cells. A clonogenic assay revealed that MCMV infection suppressed generation of colonies from single stem cells. When uninfected stem cells were induced to differentiate, a decrease in expression of the primitive neuroepidermal marker nestin was observed by immunocytochemistry and flow cytometry, whereas expression of neurofilament and glial fibrillary acidic protein (GFAP) were induced. In virus-infected CNS stem cells, nestin expression was retained, whereas the expression of neurofilament was more severely inhibited than that of GFAP in these cells. Two-color flow cytometry showed that differentiated glial precursor cells were preferentially susceptible to MCMV infection. MCMV-infected and uninfected CNS stem cells were transplanted into the neonatal rat brains. The reduced number of infected stem cells were engulfed into the subventricular zone and expressed GFAP, but did not migrate further, in contrast to the uninfected stem cells. These results suggest that suppression of the growth of the CNS stem cells and inhibition of the neuronal differentiation by CMV infection may be primary causes of disorders of brain development in congenital CMV infection.

Animals↗
PubMed2000

Heterogenous fusion transcripts involving the NUP98 gene and HOXD13 gene activation in a case of acute myeloid leukemia with the t(2;11)(q31;p15) translocation.

We report the characterization of a rare chromosomal translocation, a t(2;11)(q31;p15), which occurred in a patient with de novo acute myeloid leukemia (AML-M4). By 3'-RACE and RT-PCR analyses, two kinds of NUP98-HOXD13 fusion transcript were detected. In addition, we identified a novel fusion transcript, NUP98-FN1, in the same patient. Ectopic expression of the wild-type HOXD13 gene was also observed in the patient, suggesting that HOXD13 contributes to the development of this type of leukemia. The NUP98-HOXD13 fusion transcript was predicted to encode a 552 or 569-amino acid protein containing the Phe-Gly (FG) repeat region of NUP98 and the homeodomain of HOXD13. The NUP98-FN1 fusion transcript was predicted to encode a 482 or 499-amino acid protein consisting of the same N-terminal region of NUP98 and a C-terminal region of 12 amino acids derived from a previously unidentified sequence. We isolated and characterized the chromosomal breakpoints. The breakpoint at 11p15 is mapped within a LINE repetitive element in a 9 kb intron of NUP98, and more than 60% of the sequenced 3 kb region surrounding the breakpoint junction consists of repetitive elements. The other breakpoint at 2q31 is in an intron of FN1, which is located 7 kb upstream of HOXD13, and the repetitive sequence content of the breakpoint junction is low. Local sequence duplications at genomic breakpoints suggest that the t(2;11) translocation is mediated through staggered double-strand DNA breaks. These results throw light on the mechanisms responsible for the generation of t(2;11) translocation and on the processes leading to t(2;11) leukemia.

Acute Disease↗
PubMed2000

Use of pretreatment prostate-specific antigen doubling time to predict outcome after radical prostatectomy.

The objective of this study was to better understand the implications of the rate of prostate-specific antigen (PSA) changes in prostate carcinoma. We retrospectively calculated PSA doubling times prior to surgery in 62 patients with prostate carcinoma. The calculated values were compared with final pathologic findings and with rates of PSA failure after surgery. PSA values increased during the period of observation in 82.3% of the patients, whereas 17.7% had levels that remained stable. The median calculated PSA doubling time in those with increasing levels was 25.8 months, with doubling times </=24 months observed in 37.1% of the patients. Stage pT3 disease was more common in patients with PSA doubling times of </=36 months than in those with doubling times >36 months (P=0.02). Biochemical failure was more common in patients with rapid PSA doubling times (P<0.01). The calculated PSA doubling time prior to radical surgery is significantly associated with the final pathologic findings. Early PSA failure is more common in patients with rapid PSA doubling times prior to radical surgery. Prostate Cancer and Prostatic Diseases (2000) 3, 269-274

Journal Article↗
PubMed2000

Generation of the NUP98-HOXD13 fusion transcript by a rare translocation, t(2;11)(q31;p15), in a case of infant leukaemia.

We report a case of de novo acute myelomonocytic leukaemia with the t(2;11)(q31;p15) translocation in a Japanese female infant. The NUP98-HOXD13 fusion transcript generated by the translocation was detected in the patient's bone marrow cells by reverse transcription-polymerase chain reaction (RT-PCR). Additionally, ectopic expression of the normal allele of the HOXD13 gene was observed in this patient, suggesting that it might be associated with leukaemogenic development. This case is the third report of t(2;11) leukaemia with NUP98-HOXD13 and the first report showing that NUP98 rearrangements are associated with infant leukaemia, as well as therapy-related acute myelogenous leukaemia or myelodysplastic syndrome.

Aged↗
PubMed2000

Chewing ability and quality of life among the elderly residing in a rural community in Japan.

The present study statistically evaluates the relationship between chewing ability and quality of life (QOL) in elderly Japanese residents. We used a subjective evaluation and a mastication score determined by the food intake status to evaluate chewing ability. The PGC morale scale was used to evaluate the QOL level. The mastication score was significantly related to the QOL level in the subject group (P<0.05). The relationship between the subjective evaluation of chewing ability and the score on the PGC morale scale showed a similar tendency. In the section of the PGC morale scale that assesses agitation, attitude towards own aging, and lonely dissatisfaction, chewing ability was correlated with attitude toward own aging in particular (P<0.05). These results have suggested that the chewing ability is closely related to the QOL of the elderly residing in a rural community in Japan.

Aged↗
PubMed2000

Factors associated with admission to a geriatric hospital in semisuburban southern Japan.

A case-control study was conducted to evaluate the factors associated with admission to a geriatric hospital. Case studied were 13 Japanese elderly who were admitted to a geriatric hospital because their female caregivers had found it impossible to look after them at home. We used 35 pairs of elderly and female caregivers, who were receiving domiciliary visits by nurses, in the catchment area of the hospital. The present study revealed that elderly with dementia (vs without; Odds ratio = 6.69) and with moderately limited activities of daily living (Barthel Index 61 +) (vs severely limited activities of daily living: Barthel Index 0-60; Odds ratio = 6.62), caregivers being a daughter-in-law (vs other kinship; Odds ratio = 6.30), were risk factors.

Activities of Daily Living↗
PubMed2000

Depression among caregivers of the frail elderly in urban Japan.

A cross-sectional study was conducted in order to investigate the various factors related to the depression in caregivers of the elderly in need of care in urban Japan. The caregivers answered a self-administered questionnaire about various factors that may affect their depression, and also completed a Center for Epidemiologic Studies Depression Scale evaluation (CES-D). Compared with non-depressed caregivers, depressed caregivers attended the elderly longer, while time spent for physical caregiving did not differ between the two groups. Even after controlling confounding factors, time of attending the elderly was an independent factor related to caregiver's depression.

Aged↗
PubMed2000

Radical retropubic prostatectomy: time trends, morbidity and mortality in Japan.

OBJECTIVES: To assess the time trends, morbidity and mortality of contemporary anatomical radical retropubic prostatectomy (RRP) in a multi-institutional study in Japan, where RRP has become more popular in the last decade. PATIENTS AND METHODS: Between January 1991 and August 1998, 638 patients underwent RRP at seven urological centres in Japan. Major complications (within 30 days of surgery) and the 30-day mortality were reviewed retrospectively. Of the patients, 12.9% were < 60 years old, 56.3% were 60-69 years old and 30.9% were >/= 70 years old (median age 67). Results The number of RRPs increased markedly, by more than sevenfold, from 1991-92 to 1996-97, mainly because there were more patients undergoing RRP in their sixth decade. The contribution of T1c disease increased in absolute and relative terms, from 13.9% in 1991-92 to 37.9% in 1997-98. Over time, the mean blood loss and the allogeneic transfusion rate decreased steadily. There was a trend toward more favourable outcomes for pathological variables (an increased percentage of organ-confined disease, decreased margin positivity and a decreased incidence of positive lymph node metastasis). The most common complications were wound-related (7.5%), or anastomotic leakage (4.1%). Major cardiopulmonary complications occurred in only two patients (0.31%, both pulmonary embolisms). One patient died from cerebral haemorrhage within 30 days of surgery, giving a mortality rate of 0.16%. CONCLUSION: s This study indicates a trend towards selecting patients most likely to benefit from RRP. Although the procedure is technically demanding, it can have an acceptably low rate of early complications, little mortality and need for allogeneic transfusion. The assessment of morbidity suggests a lower incidence of catastrophic thrombo-embolic and cardiac complications in Japanese patients than in Western men. The present data may be useful in decision-analysis models evaluating the role of therapy for Asian men with early-stage prostate cancer.

Adult↗
PubMed2000

Adhesion molecule detection in a case of early cerebral malaria: immunohistochemical and electron microscopic findings.

A case of early cerebral malaria caused by Plasmodium falciparum was studied. P-selectin glycoprotein ligand 1 (PL1) was detected along the inner surface of the infected red blood cells (IRBCs), which ordinarily are not positive for PL1 immunohistochemically, suggesting PL1 being the product of parasite. The electron microscopic finding showed granular deposits in the corresponding lesion, consistent with PL1 deposition, in the IRBCs firmly attached to the endothelium of small cerebral vessels. Most of the IRBCs were round shaped as though they lost their capacity to change shape. The therapeutic strategy was expected against adhesion molecules such as PL1 and for maintaining or restoring the metamorphic capacity of IRBCs.

Animals↗
PubMed2000

Dietary intakes of flavonols, flavones and isoflavones by Japanese women and the inverse correlation between quercetin intake and plasma LDL cholesterol concentration.

The intake of flavonols, flavones and isoflavones by Japanese women was calculated from our food-phytochemical composition table. The relationship between intake of these phytochemicals and various anthropometric and blood chemistry data was analyzed in a cross-sectional study. The subjects were 115 women volunteers, aged 29-78 y, living in the northern part of Japan. Each subject completed a 3-d dietary record and received a health check up, including urine and blood sampling for biochemical analysis. Total mean intakes of flavonoids (sum of flavonols and flavones) and isoflavones were 16.7 and 47.2 mg/d, respectively. The major source of flavonoids was onions (45.9%) and that of isoflavones was tofu (37.0%). Total intake of isoflavones exceeded that of other dietary antioxidants, such as flavonoids, carotenoids (3.5 mg/d) and vitamin E (8.2 mg/d), and was approximately one half of the vitamin C intake (109 mg/d). The total intake of flavonoids was inversely correlated with the plasma total cholesterol concentration (TC) (r = -0.236, P: < 0.05) and plasma LDL cholesterol concentration (LDL-C) (r = -0.220, P: < 0.05), after the adjustment for age, body mass index and total energy intake. As a single component, quercetin was inversely correlated with both TC (r = -0.261, P: < 0.01) and LDL-C (r = -0. 263, P: < 0.01). Among Japanese, flavonoid and isoflavone intake is the main component among nonnutrient phytochemicals with antioxidant potential in the diet. These results suggest that a high consumption of both flavonoids and isoflavones by Japanese women may contribute to their low incidence of coronary heart disease compared with women in other countries.

Adult↗
PubMed2000

Alpha-synuclein inclusions in amygdala in the brains of patients with the parkinsonism-dementia complex of Guam.

We investigated by immunohistochemistry the deposition of alpha-synuclein in the brains of deceased patients with the parkinsonism-dementia complex (PDC) of Guam. Five of 13 PDC brains showed numerous alpha-synuclein positive neuronal inclusions and abnormal neurites, chiefly in the amygdala. Similar alpha-synuclein positive lesions were observed, although to a lesser extent, in the entorhinal cortex and the dorsal vagal nucleus. No alpha-synuclein positive inclusions were observed in motor cortex or locus coeruleus, and only a small number of positive inclusions were found in the Sommer's sector, temporal cortex, or substantia nigra. Some of the alpha-synuclein positive inclusions were reminiscent of cortical Lewy bodies (LB), but many of those in the amygdala coexisted with tau-positive pretangles and/or neurofibrillary tangles (NFT) within the same neurons. In these neurons, tau-positive shells encapsulated alpha-synuclein positive central cores or irregularly shaped alpha-synuclein-positive deposition intermingled with pretangles/NFT. Thus, the present study suggests that a common mechanism may govern aggregation of alpha-synuclein and tau in the amygdala, and that aggregation of alpha-synuclein may play some role in the neurodegenerative process of a tauopathy (i.e. PDC) in which Abeta deposition is virtually absent.

Adult↗
PubMed2000

Increased expression of L-type calcium channels in vascular smooth muscle cells at spastic site in a porcine model of coronary artery spasm.

Coronary artery spasm is caused primarily by increased contractility of vascular smooth muscle. Excessive Ca2+ entry into vascular smooth muscle cells (VSMCs) may be one of the key mechanisms for the spasm, but no study has ever directly examined the possible alterations of Ca2+ channels in the spastic coronary artery. Here we show that L-type Ca2+ channels are excessively expressed at the spastic site of the coronary artery. In a porcine model of coronary spasm with balloon injury, both receptor-mediated stimulation of L-type Ca2+ channels by serotonin and direct stimulation of the channels by Bay K 8644 (a dihydropyridine Ca2+ channel agonist) repeatedly induced coronary spasm in vivo, which was abolished by pretreatment with nifedipine, a dihydropyridine Ca2+ channel antagonist. In a single VSMC freshly dispersed from coronary arteries in vitro, patch-clamp experiments showed that current density of L-type Ca2+ channel current was significantly increased in VSMCs from the spastic site compared with that from the control site even when the channels were maximally stimulated by Bay K 8644. There was no difference in the sensitivity of the channels to Bay K 8644. These results indicate that functionally available L-type Ca2+ channels are excessively expressed at the spastic site of the coronary artery in our porcine model, suggesting that increased expression of L-type Ca2+ channels and concomitant increase in Ca2+ entry into VSMCs through the channels may contribute, at least in part, to the pathogenesis of coronary artery spasm.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed2000

(2-Carbamoylethyl)bis(dimethylglyoximato-N, N')

The 2-carbamoylethyl and 2-(methylcarbamoyl)ethyl groups in the title cobaloxime complexes, [Co(C(4)H(7)N(2)O(2))(2)(C(3)H(6)NO)(C(12)H(13)N)].C(2)H(6)O and [Co(C(4)H(7)N(2)O(2))(2)(C(4)H(8)NO)(C(10)H(13)NO(2))], were isomerized to 1-carbamoylethyl and 1-(methylcarbamoyl)ethyl groups, respectively, on exposure to visible light in the solid state. Although both the crystal structures and the intermolecular hydrogen bonds are different in the two crystals, similar reaction rates were observed.

Journal Article↗
PubMed2000

Mechanism of promoter melting by the xeroderma pigmentosum complementation group B helicase of transcription factor IIH revealed by protein-DNA photo-cross-linking.

The p89/xeroderma pigmentosum complementation group B (XPB) ATPase-helicase of transcription factor IIH (TFIIH) is essential for promoter melting prior to transcription initiation by RNA polymerase II (RNAPII). By studying the topological organization of the initiation complex using site-specific protein-DNA photo-cross-linking, we have shown that p89/XPB makes promoter contacts both upstream and downstream of the initiation site. The upstream contact, which is in the region where promoter melting occurs (positions -9 to +2), requires tight DNA wrapping around RNAPII. The addition of hydrolyzable ATP tethers the template strand at positions -5 and +1 to RNAPII subunits. A mutation in p89/XPB found in a xeroderma pigmentosum patient impairs the ability of TFIIH to associate correctly with the complex and thereby melt promoter DNA. A model for open complex formation is proposed.

Adenosine Triphosphate↗