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Biomedical subjects

T Hirai

Publications and source records attributed to T Hirai.

At least 37 records · Page 2Linked to original sources
PubMed2003

Unilateral ocular subalbinism in a laboratory Beagle dog.

Blue discoloration of the iris was found in the left eye of a male laboratory Beagle dog, which had a normal tricolor coat and clinically showed no visual impairment. Ophthalmoscopically, the affected eye revealed red-colored tigroid fundus, in which no tapetum was present. The retinal vasculature and the optic disc showed no noticeable changes. Histopathologically, in the left eye melanocytes had extremely few melanin granules in the anterior segment, including the anterior border layer, in the stroma and sphincter muscle of the iris and in the stroma of the ciliary body and choroid. However, the posterior pigment epithelium of the iris, the pigment epithelium of the ciliary body and the retinal pigment epithelium showed normal pigmentation. The tapetal elements were completely absent. Number and distribution of the S-100 protein-positive melanocytes with or without melanin granules in the iris, ciliary body and choroid of the left eye were similar to those of the normal right eye. Ultrastructurally, melanocytes in the anterior segment of the affected iris possessed no or few melanosomes which were incompletely melanized. In the right eye, no abnormal features were observed. Based on these results, the present case was diagnosed as unilateral ocular subalbinism with tapetal aplasia in a Beagle dog.

Albinism, Ocular↗
PubMed2003

Prediction of lymph node metastasis by p53, p21(Waf1), and PCNA expression in esophageal cancer patients.

Esophageal cancer is still one of the most widespread diseases, and surgery for esophageal carcinoma is very stressful for patients. Even though lymph node metastasis occurs more frequently in cases of early esophageal cancer than it does in cases of gastric cancer, surgeons prefer to avoid lymph node dissection if possible, thereby subjecting patients to less invasion. Thus, the aim of the present study was to examine the possibility of predicting lymph node metastasis on the basis of tumor location, quantification theory II analysis of tumor expression of genetic markers in primary esophageal cancer. Surgical specimens from 63 patients of esophageal cancer with submucosal invasion were examined for the relationship between tumor location and lymph node metastasis. In 19 of these 63 patients, p53, p21(Waf1, and proliferating cell nuclear antigen (PCNA) were examined immunohistologically, and to quantify the risk of lymph node metastasis, computer analysis was performed on the basis of quantification theory II, in which pathological lymph node metastasis (pN) was the objective variable and "high" or "low" expression of each of the three markers was the predictive variable. Tumors located in the lower third of the esophagus had no lymph node metastasis to the upper mediastinal region, and were thus indicated for trans-hiatal esophagectomy. A coefficient greater than 0.91 predicted node negative disease accurately without false-negative results; false-positive results were obtained for 54.5% of patients with a coefficient less than 0.064. Thus, we found that quantification theory II may be useful when considering indications for surgery without lymph node dissection in some cases of T1 esophageal carcinoma.

Carcinoma↗
PubMed2002

Laparoscopic cholecystectomy with two original lifting bars.

BACKGROUND: This study aimed to evaluate the efficacy of laparoscopic cholecystectomy (LC) in which the abdominal wall is lifted with two original lifting bars, especially for patients with cardiopulmonary disease. METHODS: We developed our original lifting bar. It consisted of a bent stainless steel rod 5 mm in diameter. We used two lifting bars to get a better surgical field. We performed LC on many cardiopulmonary-compromised patients. RESULTS: Since 1994, we have performed 250 LCs with good results using the two-bar method. No severe complication occurred in any LC using the two-bar method. Only two cases were converted to conventional open surgery. CONCLUSION: By traction to the teres ligament, the liver is lifted to the median abdominal wall. As a result, the surgeon can get a suitable surgical in field in which manipulate the inferior surface of the liver. Our lifting method is suitable for cardiopulmonary-compromised patients.

Adult↗
PubMed2002

Influence of tooth-loss and concomitant masticatory alterations on cholinergic neurons in rats: immunohistochemical and biochemical studies.

The influence of tooth loss on the viability of cholinergic neurons was examined in rats. At 25th postnatal week, rats were divided into the three groups; a control group fed a solid diet, a soft diet group fed a powder diet and a molar crown-less group in which all molar crowns were removed and the powder diet was given. At 15 and 35 weeks post-treatment, the number of choline acetyltransferase (ChAT)-positive neurons in the nucleus of the diagonal band/medial septal nucleus (NDB/MS) was significantly smaller in the molar crown-less group than in the control group (P < 0.01). This was not the case in the pedunculopontine tegmental nucleus or (PPT) or in the trigeminal motor nucleus. Biochemical assay showed no statistically significant differences in choline concentrations in the hippocampus between the control and the molar crown-less group both at 15 and at 35 weeks post-treatment. Nevertheless, acetylcholine (ACh) concentration in the hippocampus of the molar crown-less group was significantly lower than that of the control group at 15 weeks post-treatment (P < 0.05). Taken together, a decrease of oral sensory information may have caused a reduction in the number of ChAT-positive neurons selectively in NDB/MS, which in turn caused a decline of ACh concentrations in the hippocampus.

Acetylcholine↗
PubMed2002

Occlusal support and head posture.

In order to examine the relationship between occlusal support and head posture, the electromyographic (EMG) activities of the jaw closing muscles and the sternocleidomastoid muscle during voluntary maximal clenching (VMC) under several conditions of occlusal support in eight healthy dentates were recorded and analysed. The head posture was also recorded simultaneously by the electromagnetic, 6-degree-of-freedom tracking instrument (POLHMUS Co. 3 SPACE-WIN*). In the VMC with lateral imbalance of occlusal support, EMG activity of the jaw closing muscles and the sternocleidomastoid muscle on the occlusal support side was greater than those on the non-occlusal support side, and the neck was bent in the direction of the occlusal support side. Moreover, a positive correlation was found between the asymmetry of muscle activity (asymmetry index) of the sternocleidomastoid muscle and the angle of lateral bending of the neck. From these results, it can be said that lateral imbalance of the occlusal support could promote imbalance in sternocleidomastoid muscle activity, causing lateral bending of the neck. From this study, it is suggested that there is a close relationship between occlusal support and head posture.

Adult↗
PubMed2001

Projection structure and molecular architecture of OxlT, a bacterial membrane transporter.

The major facilitator superfamily (MFS) represents the largest collection of evolutionarily related members within the class of membrane 'carrier' proteins. OxlT, a representative example of the MFS, is an oxalate-transporting membrane protein in Oxalobacter formigenes. From an electron crystallographic analysis of two-dimensional crystals of OxlT, we have determined the projection structure of this membrane transporter. The projection map at 6 A resolution indicates the presence of 12 transmembrane helices in each monomer of OxlT, with one set of six helices related to the other set by an approximate internal two-fold axis. The projection map reveals the existence of a central cavity, which we propose to be part of the pathway of oxalate transport. By combining information from the projection map with related biochemical data, we present probable models for the architectural arrangement of transmembrane helices in this protein superfamily.

Amino Acid Sequence↗
PubMed2001

Observation of large CP violation in the neutral B meson system.

We present a measurement of the standard model CP violation parameter sin2 phi(1) based on a 29.1 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. One neutral B meson is fully reconstructed as a J/psi K(S), psi(2S)K(S), chi(c1)K(S), eta(c)K(S), J/psi K(L), or J/psi K(*0) decay and the flavor of the accompanying B meson is identified from its decay products. From the asymmetry in the distribution of the time intervals between the two B meson decay points, we determine sin2 phi(1) = 0.99+/-0.14(stat)+/-0.06(syst). We conclude that we have observed CP violation in the neutral B meson system.

Journal Article↗
PubMed2001

Respiratory modulation of muscle sympathetic nerve activity in patients with chronic heart failure.

BACKGROUND: Sympathoexcitation and respiratory instability are closely related to worsening of chronic heart failure. To elucidate the dynamic nature of respiratory modulation of sympathetic activity in patients with heart failure, we studied within-breath variation of muscle sympathetic nerve activity (MSNA) under various ventilatory volumes. METHODS AND RESULTS: MSNA, blood pressure, and respiratory flow were recorded in 23 patients with left ventricular ejection fraction </=45%. Within-breath suppression of MSNA (neural silence) was found in 11 patients (MSNA bursts: 71+/-10/100 heartbeats) but not in the remaining 12 patients (MSNA bursts: 88+/-8/100 heartbeats). Patients without neural silence had a smaller tidal volume (391+/-70 versus 267+/-75 mL/m(2), P<0.01) and a higher respiratory rate (15+/-2 versus 19+/-4 breaths/min, P<0.01) during spontaneous respiration than those with neural silence. The relationship between tidal volume and minimal amplitude of MSNA bursts in each breath was obtained during random-interval breathing and fitted by an exponential function. The curve of patients without neural silence was shifted to the right and upward, which suggests that a greater tidal volume was required to suppress MSNA (227+/-70 versus 437+/-195 mL/m(2), P<0.01). CONCLUSIONS: Sympathoexcitation in patients with chronic heart failure is closely related to both a decrease in resting tidal volume and an attenuated sympathoinhibitory effect of lung inflation reflex.

Aged↗
PubMed2001

Degradation of c-Fos protein expressed by N-methyl-D-aspartic acid in nuclear fractions of murine hippocampus.

In both nuclear and cytosolic fractions of murine hippocampus, constitutive expression was seen with Fra-2 protein, but not with other Fos family members tested including c-Fos, Fos-B and Fra-1 proteins. Fos-B protein was only detected in nuclear fractions. The systemic administration of N-methyl-D-aspartic acid (NMDA) induced marked and transient expression of c-Fos protein, but not other family members, in both hippocampal fractions 2 h later. In vitro incubation at 30 degrees C led to more rapid degradation of inducible c-Fos protein than constitutive Fra-2 protein in nuclear fractions obtained 2 h after the administration of NMDA, without significantly affecting that of both member proteins in cytosolic fractions. The addition of phosphatase inhibitors significantly delayed the initial degradation rate of inducible c-Fos protein, with concomitant facilitation of that of constitutive Fra-2 protein, in nuclear fractions. The addition of protease inhibitors also delayed the initial degradation of constitutive Fra-2 protein, without markedly altering that of inducible c-Fos protein, in nuclear fractions. Immunoprecipitation analysis revealed that NMDA induced phosphorylation of c-Fos protein on tyrosine residues in nuclear fractions to a lesser extent than that on serine residues 2 h after administration. These results suggest that NMDA signals may be propagated to the nucleus to induce both expression and degradation of c-Fos protein through a molecular mechanism associated with phosphorylation on serine and/or tyrosine residues in murine hippocampus.

Animals↗
PubMed2001

Measurement of B(0)(d)-B_(0)(d) mixing rate from the time evolution of dilepton events at the upsilon(4S).

We report a determination of the B(0)(d)-&B_(0)(d) mixing parameter Deltam(d) based on the time evolution of dilepton yields in Upsilon(4S) decays. The measurement is based on a 5.9 fb(-1) data sample collected by the Belle detector at KEKB. The proper-time difference distributions for same-sign and opposite-sign dilepton events are simultaneously fitted to an expression containing Deltam(d) as a free parameter. Using both muons and electrons, we obtain Deltam(d) = 0.463+/-0.008 (stat)+/-0.016 (syst) ps(-1). This is the first determination of Deltam(d) from time evolution measurements at the Upsilon(4S). We also place limits on possible CPT violations.

Journal Article↗
PubMed2001

Effect of JTH-601, a putative alpha(1L)-adrenoceptor antagonist, on guinea pig nasal mucosa vasculature.

The existence of alpha(1)-adrenoceptors with low affinity for prazosin, an alpha(1L) subtype, has been proposed in addition to alpha(1)-adrenoceptor subtypes with high affinity for prazosin, i.e. the alpha(1H) group: alpha(1A), alpha(1B) and alpha(1D) subtypes. In the present study, we investigated the effect of JTH-601 (3-(N-[2-(4-hydroxy-2-isopropyl-5-methylphenoxy)ethyl]-N-methylaminomethyl)-4-methoxy-2,5,6-trimethylphenol hemifumarate), a putative alpha(1L)-adrenoceptor antagonist, on the isolated guinea pig nasal mucosa vasculature. JTH-601 (0.01-0.03 microM) competitively antagonized the noradrenaline-induced contraction of the tissue in a concentration-dependent manner. The pA(2) value for JTH-601 was 8.14 +/- 0.04 (means +/- SEM, n = 6). The data suggests that the alpha(1L)-subtype is involved in the noradrenaline-induced contraction of the guinea pig nasal mucosa vasculature.

Adrenergic alpha-1 Receptor Antagonists↗
PubMed2001

Measurement of the CP violation parameter sin2 phi(1) in B(0)(d) meson decays.

We present a measurement of the standard model CP violation parameter sin2 phi(1) (also known as sin2beta) based on a 10.5 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e(+)e(-) collider. One neutral B meson is reconstructed in the J/psiK(S), psi(2S)K(S), chi(c1)K(S), eta(c)K(S), J/psiK(L), or J/psipi(0) CP-eigenstate decay channel and the flavor of the accompanying B meson is identified from its charged particle decay products. From the asymmetry in the distribution of the time interval between the two B-meson decay points, we determine sin2 phi(1) = 0.58(+0.32)(-0.34)(stat)+0.09-0.10(syst).

Journal Article↗
PubMed2001

Photorearrangement of vinylidenecyclopropanes to 1,2,3-butatriene derivatives.

[reaction: see text] Photoirradiation of benzene solutions containing 1-diarylvinylidene-2,2,3,3-tetramethylcyclopropanes (2a--d) afforded rearranged products 1,2,3-butatrienes (3a-d) in good to high yields. Photorearrangement from 2,2,3-trimethyl and 2,2- and 2,3-dimethyl derivatives 2e--g also proceeded, but the rates of the rearrangement were lower than those of 2a--d. A singlet mechanism is proposed for this photorearrangement, where alkyl migration occurs from 1,3-biradical intermediates generated via the homolysis of the C1-C2 bond. Generation of diarylvinylidene carbenes from 1,3-biradicals might be competitive with the formation of 3.

Journal Article↗
PubMed2001

Is Borrmann type IV gastric carcinoma a surgical disease? An old problem revisited with reference to the result of peritoneal washing cytology.

BACKGROUND AND OBJECTIVES: Borrmann type IV gastric carcinoma (B-4) remains a disease with poor prognosis despite an aggressive surgical approach. Cytology examination of the peritoneal washes is an established prognostic factor for gastric carcinoma in general, and may be useful for identifying adequate treatment strategy for B-4. METHODS: Pathologic data from 70 patients with B-4 who underwent laparotomy and peritoneal washing cytology during the recent 6 years were retrieved from a prospective computer database and reviewed. Prognostic significance of the cytology examination along with other known clinicopathologic variables was evaluated by univariate and multivariate analyses. RESULTS: Long-term survivors were observed only among the patients who were treated with curative R0 resection. Prognosis of the patients with positive cytology and no other residual disease (R1) was extremely poor and was equivalent to that of the patients undergoing noncurative R2 resection. No difference in survival, either, was observed between the patients treated by R2 resection and those who did not undergo resection. Multivariate analysis identified cytology examination as an independent prognostic factor. CONCLUSIONS: Peritoneal washing cytology plays an important role in staging B4. Positive cytology findings as well as other evidence of disseminated disease may indicate that gastrectomy should be avoided.

Demography↗
PubMed2001

Slc19a2: cloning and characterization of the murine thiamin transporter cDNA and genomic sequence, the orthologue of the human TRMA gene.

Recently, our group and others cloned the TRMA disease gene, SLC19A2, which encodes a thiamin transporter. Here, we report the cloning and characterization of the full-length cDNA and genomic sequences of mouse Slc19a2. The Slc19a2 cDNA contained a 1494-bp open-reading frame, and had 5'- and 3'-untranslated regions of 189 and 1857 bp, respectively. A putative GC-rich, TATA-less promoter was identified in genomic sequence directly upstream of the identified 5' end. The Slc19a2 gene spanned 16.3 kb and was organized into six exons, a gene structure conserved with the human orthologue. The predicted Slc19a2 protein, like SLC19A2, was predicted to have 12 transmembrane domains and shared a number of other conserved sequence motifs with the human orthologue, including one potential N-glycosylation site (N(63)) and several potential phosphorylation sites. Comparison of the Slc19a2 amino acid sequence with those of the other known SLC19A solute carriers highlighted interesting patterns of conservation and divergence in various domains, allowing insight into potential structure-function relationships. The identification of the mouse Slc19a2 cDNA and genomic sequences will facilitate the generation of an animal model of TRMA, permitting future studies of disease pathogenesis.

Amino Acid Sequence↗
PubMed2001

Multiple thymoma with myotonic dystrophy.

A case of multiple thymoma associated with myotonic dystrophy is reported. The patient was a 42-year-old man who had two separate encapsulated thymoma in the anterior mediastinum, at 3 cm in diameter on the right side, and at 4 cm in diameter on the left. Extended thymo-thymomectomy was performed. Microscopically, the tumor in the right thymic lobe was predominantly mixed type, and that in the left predominantly epithelial type. Neuromuscular disease appeared to develop, with severe sputum retention in the larynx and he was referred to neurology at 6 months after surgery. On examination, he presented a characteristic hatchet face, muscle atrophy, muscle weakness, percussion myotonia and grip myotonia, and diagnosis was revised to be multiple thymoma associated with myotonic dystrophy. This association is extremely rare. It is difficult to clarify whether this association was a syndrome or coincidence.

Adult↗