Biomedical subjects

M Taira

Publications and source records attributed to M Taira.

At least 73 records · Page 4Linked to original sources

PubMed1998

Prevalence and clinical features of hepatitis delta virus infection in the Miyako Islands, Okinawa, Japan.

The aims of this study were twofold: (1) to determine the prevalence and clinical features of hepatitis delta virus (HDV) infection among subjects positive for hepatitis B surface antigen (HBsAg) living in the Miyako Islands, Okinawa Prefecture, Japan, and (2) to clarify the relationship between HDV-RNA level and severity of HDV-related liver disease. One hundred and ninety-nine HBsAg-positive subjects (123 asymptomatic carriers [ASCs], 3 patients with acute hepatitis [AH], 50 patients with chronic hepatitis [CH], 15 patients with liver cirrhosis [LC], and 8 patients with hepatocellular carcinoma [HCC], were tested for antibody to HDV (anti-HDV) by radioimmunoassay. Anti-HDV-positive individuals were examined to determine semi-quantified HDV-RNA level by polymerase chain reaction (PCR). The overall prevalence of anti-HDV among the 199 subjects was 21.1%. The positivity rate tended to increase with age or the severity of the underlying liver disease: anti-HDV-positive rates were 10.6% (13/123) in ASCs, 32.0% (16/50) in patients with CH, 40.0% (6/15) in patients with LC, and 87.5% (7/8) in patients with HCC. None of the patients with AH were positive for anti-HDV. There was no correlation between semi-quantified serum HDV-RNA levels and the severity of chronic liver disease in patients positive for anti-HDV. The present study showed the local spread of HDV infection in the Miyako Islands, Okinawa, Japan. Although the anti-HDV positivity rate tended to increase with the severity of the underlying liver disease, the severity of HDV-related liver disease did not correlate with the semi-quantified serum HDV-RNA level.

Adolescent↗

PubMed1998

Heterogeneous fluoridated apatites synthesized with a three-step fluoride supply system.

Two types of heterogeneous fluoridated apatite, H-F-H and F-H-F, were synthesized by supplying fluoride during the middle half (H-F-H) or initial and final quarters (F-H-F) of the experimental period. Although X-ray diffraction patterns and SEM photographs of both H-F-H and F-H-F-type apatites were not significantly different, high-resolution transmission electron microscopy showed quite different features; H-F-H-type apatite crystals were elongated hexagons, while those of F-H-F-type apatite were rather wider hexagons with electron damage in three-quarters of the inner core. These results supported the previous speculations on the two different types of heterogeneous fluoridated hydroxyapatites synthesized with fluoride concentrations stoichiometrically equivalent to that of fluorapatite: hydroxyapatite covered with fluorapatite and fluorapatite covered with hydroxyapatite. F-H-F-type apatite was less soluble than that of H-F-H-type apatite.

Apatites↗

PubMed1998

Differential expression of non-muscle myosin heavy chain genes during Xenopus embryogenesis.

Class II non-muscle myosins are implicated in diverse biological processes such as cytokinesis, cellularization, cell shape changes and gastrulation. Two distinct non-muscle myosin heavy chain genes have been reported in all vertebrates: non-muscle myosin heavy chain-A (NMHC-A) and -B (NMHC-B). We report here the isolation of the Xenopus homolog of NMHC-A and present a comparative analysis of the developmental and spatial expression patterns of NMHC-A and the previously isolated NMHC-B to address the role of NMHCs in Xenopus development. A 7.5 kb NMHC-A mRNA is present, maternally in unfertilized eggs and throughout embryogenesis, as well as in all adult tissues examined. An additional 8.3 kb zygotic transcript for NMHC-A is also detected, but only during embryonic stages. Whole mount in situ hybridization with tailbud stage embryos shows that NMHC-A mRNA is predominantly expressed in the epidermis, whereas NMHC-B mRNA is expressed in the somites, brain, eyes and branchial arches. Interestingly, the expression of NMHC-B in developing somites is gradually restricted to the center of each somite as differentiation proceeds. DAPI nuclear staining demonstrated that NMHC-B mRNA is colocalized with the nuclei or perinuclear area. In animal cap experiments, treatment with activin A or ectopic expression of Xbra and an activated form of Xlim1 markedly up-regulates NMHC-B as well as muscle actin mRNAs and slightly down-regulates NMHC-A mRNA, consistent with NMHC-B expression in the somitic muscle and NMHC-A expression in the epidermis.

Activins↗

PubMed1998

Sleep-wake rhythm of autistic children.

Using a sleep log for 28 days in the summer vacation, 89 autistic children living in a suburb of Tokyo were examined. Only one girl of 13 years showed a tendency of non-24 h sleep-wake syndrome. Most autistic children showed a large variation of total sleep time. Forty per cent of subjects showed 10% or more on coefficient of variation of total sleep time. In the retiring and rising time, many subjects tended to show late retiring and early rising.

Adolescent↗

PubMed1998

Sleep disorder in children with autism.

Eighty-eight children with autism, living in a suburb of Tokyo, were examined by questionnaire from 21 July to 31 August. Experienced sleep disorders were observed in 56 children; 44 of whom had sleep disorders before 3 years old. The average age when sleep disorders were seen to have stopped was 5 years old. The most common problem was difficulty falling sleep (n=23), followed by frequent awakening during sleep time (n=19), then early morning awakening (n=11). Bed-wetting was observed in 22 children.

Adolescent↗

PubMed1998

MUC-1 mucin expression in invasive areas of intraductal papillary mucinous tumors of the pancreas.

The expression of MUC-1 mucin (membrane-associated mucin) and MUC-2 mucin (secretory mucin) were immunohistochemically examined in 46 invasive ductal carcinomas (IDC) and 16 intraductal papillary mucinous tumors (IPMT) of the pancreas. Intraductal papillary mucinous tumors usually reveal expansive growth. However, of the 16 IPMT examined in the present study, three showed an invasive growth pattern, which was similar to 'mucinous carcinoma', around the non-invasive growth areas. Of 46 IDC, MUC-1 mucin detected by monoclonal antibodies, DF3 and MY.1E12, was expressed in 44 cases (96%) and in 45 cases (98%), respectively, whereas MUC-2 mucin detected by polyclonal antibody, anti-MRP, was not expressed in any of the cases (0%). In contrast, in the non-invasive growth areas of the 16 IPMT, MUC-1 mucin detected by DF3 and MY.1E12 was expressed in four cases (25%) and in six cases (38%), respectively, whereas MUC-2 mucin detected by anti-MRP was expressed in 13 cases (81%). The invasive growth areas of the three IPMT showed positive expression of MUC-1 mucins detected by DF3 and MY.1E12, although the non-invasive growth areas showed negative expression of MUC-1 mucins, except for their focal positive expression in one of the three cases. These findings indicate that the invasive growth areas of IPMT acquire a characteristic of MUC-1 mucin expression that is usually seen in IDC.

Biomarkers, Tumor↗

PubMed1998

[Severe hypertriglyceridemia induced by tamoxifen].

A 71-year-old woman was admitted to our hospital because of severe hypertriglyceridemia. The patient had a 26-year history of non-insulin-dependent diabetes mellitus and hyperlipidemia (T-chol 300 mg/dl, TG 300 mg/dl). She was treated with sulfonylurea and clofibrate. Seven years before admission, she had undergone a radical mastectomy for cancer of the left breast. After the operation, she had received tamoxifen and fluorouracil. One month before admission, she had marked hypertriglyceridemia (triglyceride 2,106 mg/dl). After discontinuation of tamoxifen and fluorouracil, her serum triglyceride level decreased to 372 mg/dl; when tamoxifen was given again, it increased to 581 mg/dl, and her hepatic triglyceride lipase activity decreased from 0.228 to 0.164 mumol FFA/ml/min. Apolipoprotein E phenotype was wild type E3/3. The concentration of sex-hormone-binding globulin increased from 110 to 130 nmol/l. These changes associated with tamoxifen treatment were similar to those seen after administration of estrogen. Tamoxifen, an anti-estrogen, has been used as adjuvant therapy in cases of estrogen-receptor-positive breast cancer. Tamoxifen has some weak estrogenic activity. The tamoxifen-induced hypertriglyceridemia seen in this case was an effect of its estrogenic action.

Aged↗

PubMed1998

Improvement of bond strength in metal-ceramic systems using a gold intermediate layer.

The mechanism of bonding between metal and ceramic in systems using the functionally graded method with pure gold and gold mixture as a primer was examined. Four types of samples, porcelain, porcelain-gold, porcelain-metal and porcelain-gold-metal were prepared. The gold intermediate layer was fired at 1000 degrees C. For porcelain and metal, low-fusing opaque, body porcelain and palladium alloy were used. The intermediate layer was composed of three layers; pure gold, gold-palladium and gold-porcelain layer. During the bending test of each sample, the porcelain peeled away from the porcelain-metal system, while porcelain with the gold intermediate layer remained on the metal surface even after maximal loading. The bond strength of the porcelain-gold-metal system was much higher than that of the porcelain-metal system, and the toughness of the former was much greater than that of the latter. Laser microscopy and scanning electron microscopy (SEM) showed a smooth interface between the intermediate layer and the metal which suggested proper chemical bonding, and no gap was observed. At the interface between the porcelain and the gold intermediate alloy, a good mechanical anchor lock was observed. Electron probe microanalysis (EPMA) showed a clear distribution of each element (e.g. Si, Au and Pd) in the porcelain, gold intermediate layer and metal frame.

Dental Bonding↗

PubMed1998

[Adult multiple coronary aneurysms of Kawasaki's disease's sequelae; two autopsy cases].

Coronary aneurysm in Kawasaki's disease (Acute febril infantile mucocutaneous lymph node syndrome, MCLS) may cause sudden death in childhood and ischemic heart disease in adults. We encountered two adult autopsy cases of Kawasaki's disease with multiple coronary aneurysms. The first case was a 56-year-old man who hospitalized due to recurrent syncope since 51 years of age. At age 55 coronary angiography (CAG) had shown multiple aneurysms in the left and right coronary artery. In September 1991, he developed chest pain and was brought to the hospital, almost dead on arrival (DOA). The patient died later the same day despite cardiopulmonary resuscitation. Autopsy findings showed cardiomegaly (470 g) with multiple coronary aneurysms of three coronary arteries. Microscopically, intimal thickening and medial thinning were found in the aneurysmal wall with calcification and disruption of the internal elastic lamina. The second case, a 28-year-old man had been diagnosed with rheumatic fever and mitral regurgitation at 4 years of age. Coronary aneurysms were noted on CAG at 26 years of age. In April 1992, he developed fever and was admitted to a local hospital where he was diagnosed with infectious endocarditis. After his being transferred to our hospital, disturbance of consciousness suddenly developed and he died in September 1992. Autopsy findings showed cardiomegaly (430 g) with left ventricular hypertrophy and multiple coronary aneurysms in left anterior descending coronary artery and left circumflex coronary artery. The aneurysmal wall showed intimal thickening and medial thinning with multiple recanalizations of occlusive lumina and fibrous intimal thickening. The mitral valve showed mild fibrosis and calcification without valvular deformity. There was no evidence of bacterial endocarditis. Both cases were finally diagnosed as Kawasaki's disease. Ischemic heart disease or lesions related to coronary aneurysm in Kawasaki's disease may show an increased incidence in the near future. Kawasaki's disease should have been followed even in adulthood after treatment in childhood.

Adult↗

PubMed1998

[Insulin receptor abnormality and its clinical aspect].

About 50 cases of insulin receptor abnormality were reported after in 1985 when human insulin receptor cDNA was cloned. The abnormalities were found in syndrome of type A insulin resistance, Leprechaunism, and syndrome of Rabson-Mendenhall. We have reported 3 families with insulin receptor gene abnormality, Type C (Chiba), Type A (Yamanashi) and Type C (Hokkaidou-2). Type C (Chiba) and Type A (Yamanashi) have a deletion of from 17 to 22 exon and 14 exon of insulin receptor gene, respectively. Type C(Hokkaidou-2) shows a substitution of valine for glycine at codon 1008 in the tyrosine kinase domain. They all showed the typical symptoms of type A insulin resistance, and the insulin resistance was dominantly inherited in the family of Type C(Chiba) and Type C(Hokkaidou-2), and not in the family of Type A(Yamanashi).

Acanthosis Nigricans↗

PubMed1997

Studies on the role of fibroblast growth factor signaling in neurogenesis using conjugated/aged animal caps and dorsal ectoderm-grafted embryos.

Basic fibroblast growth factor (bFGF) has been shown to induce neural fate in dissociated animal cap (AC) cells or in AC explants cultured in low calcium and magnesium concentrations. However, long-term disclosure of the cap may cause diffusion of the secreted molecule bone morphogenetic protein 4 (BMP-4), a neural inhibitor present in the AC. This may contribute to the subsequent neurogenesis induced by bFGF. Here we used conjugated and aged blastula AC to avoid diffusion of endogenous molecules from the AC. Unlike noggin, bFGF failed to induce neural tissue in this system. However, it enhanced neuralization elicited by a dominant negative BMP receptor (DN-BR) that inhibits the BMP-4 signaling. Posterior neural markers were turned on by bFGF in AC expressing DN-BR or chordin. Blocking the endogenous FGF signal with a dominant negative FGF receptor (XFD) mainly inhibited development of posterior neural tissue in neuralized ACs. These in vitro studies were confirmed in vivo in embryos grafted with XFD-expressing ACs in the place of neuroectoderm. Expression of some regional neural markers was inhibited, although markers for muscle and posterior notochord were still detectable in the grafted embryos, suggesting that XFD specifically affected neurogenesis but not the dorsal mesoderm. The use of these in vitro and in vivo model systems provides new evidence that FGF, although unable to initiate neurogenesis on its own, is required for neural induction as well as for posteriorization.

Animals↗

PubMed1997

Role of the Xlim-1 and Xbra genes in anteroposterior patterning of neural tissue by the head and trunk organizer.

Anteroposterior patterning of neural tissue is thought to be directed by the axial mesoderm which is functionally divided into head and trunk organizer. The LIM class homeobox gene Xlim-1 is expressed in the entire axial mesoderm, whereas the distinct transcription factor Xbra is expressed in the notochord but not in the prechordal mesoderm. mRNA injection experiments showed that Xenopus animal explants (caps) expressing an activated form of Xlim-1 (a LIM domain mutant named 3m) induce anterior neural markers whereas caps coexpressing Xlim-1/3m and Xbra induce posterior neural markers. These data indicate that, in terms of neural inducing ability, Xlim-1/3m-expressing caps correspond to the head organizer and Xlim-1/3m plus Xbra-coexpressing caps to the trunk organizer. Thus the expression domains of Xlim-1 and Xbra correlate with, and possibly define, the functional domains of the organizer. In animal caps Xlim-1/3m initiates expression of a neuralizing factor, chordin, whereas Xbra activates embryonic fibroblast growth factor (eFGF) expression, as reported previously; these factors could mediate the neural inducing and patterning effects that were observed. A dominant-negative FGF receptor (XFD) inhibits posteriorization by Xbra in a dose-dependent manner, supporting the suggestion that eFGF or a related factor has posteriorizing influence.

Animals↗

PubMed1997

Expression of murine Lhx5 suggests a role in specifying the forebrain.

A LIM homeobox gene, Lim5, is known to be expressed in the forebrain of Xenopus and zebrafish (Toyama et al. [1995] Dev. Biol. 170:583-593). Results from developmental and comparative studies of its mouse ortholog, Lhx5, indicate that this gene may play important roles in forebrain development. Lhx5 expression is detected in the most anterior portion of the neural tube at the headfold stage, overlapping partially with Otx2 expression domain. After neural tube closure, Lhx5 is expressed as a transverse stripe, covering most of the diencephalic primordium. This expression recedes to restricted areas as Dlx gene expression occurs. By midgestation, both genes, Lhx5 and Dlx5, are expressed in the diencephalon and ventral telencephalon in an alternating complementary pattern. It may be that Dlx inhibits Lhx5, and this may represent a step of early regionalization of the forebrain. Lhx5 is also expressed in midbrain, hindbrain, and spinal cord, overlapping extensively with Lhx1 starting from day E10.5 of gestation. The early, persistent, and dynamic expression of Lhx5 suggests a regulatory function in forebrain formation.

Amino Acid Sequence↗

PubMed1997

Rietveld analysis and Fourier maps of hydroxyapatite.

Rietveld analysis was applied to the X-ray powder diffraction data of well-crystallized hydroxyapatites synthesized at 80 degrees C and pH 7.4. The least-squares refinement program adopted for Rietveld analysis showed good pattern fitting with the calculated profile. The a- and c-axis dimensions, a-0.943046 + 0.000126 nm and c-0.687485 +/- 0.000104 nm, were obtained and compared with the data estimated from a single peak. The lattice dimensions obtained by Rietveld analysis were much closer to the values of a single crystal, a = 0.9432 nm and c-0.6881nm. Fourier analysis was also performed. The maps of electron densities expressed the existing possibility of each atom composing hydroxyapatite in the crystal structure. In particular, columnar calcium and screw-axis calcium were clearly revealed. These data agreed well with the computer graphics model of hydroxyapatite reported previously.

Computer Simulation↗

PubMed1997

The TINS Lecture. The parietal association cortex in depth perception and visual control of hand action.

Recent neurophysiological studies in alert monkeys have revealed that the parietal association cortex plays a crucial role in depth perception and visually guided hand movement. The following five classes of parietal neurons covering various aspects of these functions have been identified: (1) depth-selective visual-fixation (VF) neurons of the inferior parietal lobule (IPL), representing egocentric distance; (2) depth-movement sensitive (DMS) neurons of V5A and the ventral intraparietal (VIP) area representing direction of linear movement in 3-D space; (3) depth-rotation-sensitive (RS) neurons of V5A and the posterior parietal (PP) area representing direction of rotary movement in space; (4) visually responsive manipulation-related neurons (visual-dominant or visual-and-motor type) of the anterior intraparietal (AIP) area, representing 3-D shape or orientation (or both) of objects for manipulation; and (5) axis-orientation-selective (AOS) and surface-orientation-selective (SOS) neurons in the caudal intraparietal sulcus (cIPS) sensitive to binocular disparity and representing the 3-D orientation of the longitudinal axes and flat surfaces, respectively. Some AOS and SOS neurons are selective in both orientation and shape. Thus the dorsal visual pathway is divided into at least two subsystems, V5A, PP and VIP areas for motion vision and V6, LIP and cIPS areas for coding position and 3-D features. The cIPS sends the signals of 3-D features of objects to the AIP area, which is reciprocally connected to the ventral premotor (F5) area and plays an essential role in matching hand orientation and shaping with 3-D objects for manipulation.

Animals↗

PubMed1997

Studies on dental high-speed cutting of commercial pure titanium (Ti) and free-machining titanium (DT-2F).

Some dental prostheses are formed by machining. The purpose of this study was to evaluate the dental high-speed cutting behaviour of free-machining titanium (Ti), the ease in cutting of which is metallurgically improved. Weight-load cutting tests were performed on commercial pure Ti and free-machining Ti, using a diamond point and a carbide burr. It became evident that the cutting effectiveness of two rotary cutting instruments on free-machining Ti was superior to that on commercial pure Ti due to the formation of accelerated cut debris. Cutting of free-machining Ti resulted in less damage of the carbide burr, compared with the cutting of commercial pure Ti. These results suggest that free-machining Ti is a suitable workpiece for dental Ti-based machined prostheses.

Carbon↗

PubMed1997

Clinical features of patients with chronic liver disease associated with hepatitis C virus genotype 1a/I in Okinawa, Japan.

The clinical characteristics of chronic hepatitis C virus (HCV) carriers with HCV genotype 1a/I infection were investigated and compared with those of chronic HCV carriers infected with 1b/II, 2a/III, 2b/IV and the mixed type of infection. We found that 16 of 408 (3.9%) carriers had HCV genotype 1a infection, comprising four of 67 (6.0%) blood donors, 11 of 263 (4.2%) patients with chronic hepatitis and one of 39 (2.6%) patients with liver cirrhosis. Three of 408 subjects had a mixed infection of genotypes 1a/I and 1b/II. All carriers with genotype 1a (including those with the mixed infection) were of Japanese origin and all, except one who was born in Brazil, were born in Okinawa Prefecture. Nine of 14 patients infected with genotype 1a for whom medical records were obtained had a history suggestive of infection through blood exposure; six had had blood transfusions, one had tattoos, one is a nurse and one had a history of drug addiction. There were no haemophiliacs or other multitransfused patients in the genotype 1a group. Of 10 patients infected with genotype 1a who received interferon (IFN) therapy, four (40%) showed a complete response. Although the small number of patients infected with genotype 1a in the present study precluded statistical analysis of the response to IFN, the response in patients with genotype 1a was better than the response in those infected with genotype 1b and poorer than the response in those patients infected with genotype 2a/III or 2b/IV.

Adult↗

PubMed1997

Seroepidemiological study on hepatitis delta virus infection in the Irabu Islands, Okinawa, Japan.

A seroepidemiological study was performed to clarify the prevalence of hepatitis delta virus (HDV) infection among the general population in the Irabu islands, Okinawa, Japan. Of 2028 healthy people examined who had received their annual health check-up in 1994-95, 195 (9.6%) were positive for hepatitis B surface antigen (HBsAg). Of these 195 HBsAg-positive individuals, 46 (23.6%) showed a positive reaction for antibody to HDV (anti-HDV). The positivity rate of anti-HDV among HBsAg-positive subjects tended to increase with age up to 50-59 years of age. The prevalence of anti-HDV also varied among the seven districts in the islands (0-63.3%). None of the anti-HDV-positive subjects was included in the high risk group for parenterally transmitted diseases. The unusually high prevalence of anti-HDV among HBsAg-positive individuals, particularly in the older age groups, seemed to reflect the natural prevalence or previous HDV infection, rather than a current or imported infection of HDV. Although the great majority of HBsAg-positive subjects with anti-HDV were asymptomatic, abnormally high values of serum transaminases were more frequently seen in these subjects compared with HBsAg-positive subjects without anti-HDV.

Adult↗