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Biomedical subjects

T Hayashi

Publications and source records attributed to T Hayashi.

At least 217 records · Page 12Linked to original sources
PubMed2001

Pulsatility of ascending aortic blood pressure waveform is associated with an increased risk of coronary heart disease.

BACKGROUND: Although it was reported that pulse pressure of the peripheral artery could differentiate patients with coronary heart disease (CHD) from those without CHD, it is not known whether pulsatility of the ascending aortic pressure waveform differentiates patients with CHD from those without CHD. The purpose of this study was to evaluate whether the pulsatility of ascending aortic pressure is associated with an increased risk of CHD. METHODS: For this study, we enrolled 293 subjects who had chest pain, normal contractions, no local asynergy, and no history of myocardial infarction. We measured the ascending aortic pressure using a fluid-filled system. To quantify the relative magnitude of the pulsatile to mean artery pressure, we normalized the pulse pressure to the mean pressure and referred to this value as the fractional pulse pressure (PPf). We investigated the association between the PPf and the risk of CHD. RESULTS: The PPf of the ascending aorta was associated with an increased risk of CHD. The multiple-adjusted odds ratio of CHD was 2.93 (95% CI, 1.44 to 5.94) for the middle tertile of the PPf level and was 3.93 (95% CI, 1.74 to 8.85) for the highest tertile compared with the lowest tertile. CONCLUSION: Ascending aortic pulsatility is related to an increased risk of CHD.

Aged↗
PubMed2001

Diversification of cell types in the Drosophila eye by differential expression of prepattern genes.

According to Freeman (Development, 124 (1997) 261), reiterative use of Spitz signals emanating from already differentiated ommatidial cells triggers the differentiation of around ten different types of cells. Here we show evidence that the choice of cell fate by newly recruited ommatidial cells strictly depends on their developmental potential. Using forced expression of a constitutively active form of Ras1, three developmental potentials (rough, seven-up, and prospero expression) were visualized as relatively narrow bands corresponding to regions where rough-, seven-up- or prospero-expressing ommatidial cells would normally form. Ras1-dependent expression of ommatidial marker genes was regulated by a combinatorial expression of eye prepattern genes such as lozenge, dachshund, eyes absent, and cubitus interruptus, indicating that developmental potential formation is governed by region-specific prepattern gene expression.

Animals↗
PubMed2001

Lipolytic effect of BRL 35 135, a beta3 agonist, and its interaction with dietary lipids on the accumulation of fats in rat body.

The type of intaked fat and fat uptake mechanisms such as adrenergic-induced lipolysis affect patterns of fat accumulation in animal body. In this study, in vitro lipolytic effect of BRL 35135, a selectivebeta3 agonist, and its interaction with different dietary fats on fat accumulation in animal body (in vivo) were studied. For in vitro study, adipocytes isolated from epididymal fat were incubated with 10(-5) M -10(-9) M of either BRL 35135 or isoproterenol, a non-selectivebeta-agonist. In animal study, two groups of SD-rats, i.e., BRL35135-intaked (dosed at 0.5 mg/kg/day in diet) and control, were divided into 4 sub-groups and fed diets containing 12% of either beef tallow (BT), canola oil (CO), olive oil (OO) or safflower oil(SO) for 6 weeks. In vitro study showed that BRL 35135 was 10 times more potent than isoproterenol in increasing the lipolysis in rat adipocytes. In animal study, inclusion of BRL35135 reduced daily weight gain in CO and SO groups (P < 0.05). Abdominal fat weight in BRL35135-intaked group was significantly lower than control in all dietary sub-groups (CO, OO and SO) except BT (P < 0.05). In BT group, abdominal fat contained significantly higher amount of total saturated fatty acids (SFAs) compared to CO, OO or SO. It was concluded that, although BRL 35135 was very potent in increasing lipolysis in the isolated adipocytes of rat, its preventive effect on lipid accumulation in animal body through the lipolysis could be affected by the type of dietary fat and was lesser when rats fed fats rich in SFAs.

Journal Article↗
PubMed2001

Diversification of Escherichia coli genomes: are bacteriophages the major contributors?

Determination of the genome sequence of enterohemorrhagic Escherichia coli O157 Sakai and genomic comparison with the laboratory strain K-12 has revealed that the two strains share a highly conserved 4.1-Mb sequence and that each also contains a large amount of strain-specific sequence. The analysis also revealed the presence of a surprisingly large number of prophages in O157, most of which are lambda-like phages that resemble each other. Based on these results, we discuss how the E. coli strains have diverged from a common ancestral strain, and how bacteriophages contributed to this process. We also describe possible mechanisms by which O157 acquired many closely related phages, and raise the possibility that such bacteria might function as 'phage factories', releasing a variety of chimeric or mosaic phages into the environment.

Bacteriophage lambda↗
PubMed2001

The fibril structure of type V collagen triple-helical domain.

Although the triple-helical structure of fibrillar collagen is regarded in general as being quite similar, each type of collagen molecule has inherent characteristics in the triple-helical domain. Few studies have ever been performed in terms of the aggregate structure of the triple-helical domain of fibrillar collagen. Reconstituted aggregates from the purified triple-helical domain of each type of fibrillar collagen might amplify the subtle differences in the structural characteristics of each type of collagen molecule. In this study, the reconstituted aggregate structure of pepsin-treated type V collagen (type Vp collagen), that is, virtually its triple-helical domain was characterized by transmission electron microscopy. Pepsin-treated type I (type Ip) and type II (type IIp) collagen were compared with type Vp collagen. Unique features of the aggregate structure of the triple-helical domain of the type V collagen can be summarized as follows:These results suggested that the lateral packing of the triple-helical domain of type V collagen is determined by its molecular structure. The characteristics of type Vp collagen fibrils might be explained by their characteristic amino acid composition. A significant feature of the triple-helical domain of type V collagen is the high content of glycosylated hydroxylysine residues. Molecular model building of the collagenous structure suggests that a change in surface roughness is conspicuous by incorporating the glycosylated hydroxylysine residues. More than a ten-fold content of bulky glycosylated hydroxylysine residues in type V collagen compared to that of type I might have a significant influence on both the intermolecular and interfibrillar interactions of the triple-helical domain of type V collagen molecule.

Amino Acid Sequence↗
PubMed2001

Measurements of LET-distribution, dose equivalent and quality factor with the RRMD-III on the Space Shuttle Missions STS-84, -89 and -91.

Dosimetric measurements on the Space Shuttle Missions STS-84, -89 and -91 have been made by the real-time radiation monitoring device III (RRMD-III). Simultaneously, another dosimetry measurement was made by the Dosimetry Telescope (DOSTEL) on STS-84 and by the tissue-equivalent proportional counter (TEPC) on STS-91. First, the RRMD-III instrument is described in detail and its results summarized. Then, the results of DOSTEL and TEPC are compared with those of the RRMD-III. Also, the absorbed doses obtained by TLD (Mg2SiO4) and by RRMD-III on board STS-84 and -91 are compared.

Atlantic Ocean↗
PubMed2001

S-myotrophin promotes the hypertrophy of myotube as insulin-like growth factor-I does.

We have reported previously that a novel muscle cell growth factor, having a structure of a peptide with sugar chains, was successfully purified from porcine skeletal muscle. It was named s-myotrophin. To determine the role of s-myotrophin in skeletal muscle growth, the effect of s-myotrophin on primary cultured chick skeletal muscle cells (composed almost totally of multinucleated myotubes) was investigated by comparing s-myotrophin with Insulin-like growth factor-I (IGF-I). Both s-myotrophin and IGF-I significantly increased creatine kinase activity of the cultures; both substances gave similar responses. Intracellar protein content was also increased by the addition of these factors. The content of myosin and actin in s-myotrophin treated culture in the differentiation medium was significantly higher than that of the control (unstimulated). The content of those proteins in IGF-I treated culture was also higher than that of control, but the differences were not statistically significant. Immunoblot analysis confirmed that the amounts of myosin and actin in the myocytes were greatly increased by s-myotrophin stimulation and also by IGF-I stimulation. Morphological observations using an anti-desmin antibody staining procedure demonstrated that the size of both s-myotrophin and IGF-I treated myotubes was appreciably larger than that of control myotubes. These results suggest that s-myotrophin is a potent mediator of skeletal muscle cell hypertrophy thorough the accumulations of muscle structural proteins.

Actins↗
PubMed2001

Pressure-induced denaturation of monomer beta-lactoglobulin is partially irreversible: comparison of monomer form (highly acidic pH) with dimer form (neutral pH).

This study was conducted to assess the effect of high hydrostatic pressure on monomer beta-lactoglobulin (BLg) at acid pH by fluorescence spectroscopy under pressure and by circular dichroism (CD) and (1)H NMR spectroscopies after release of pressure. The intrinsic (tryptophan) fluorescence measurement and the study of 8-anilinonaphthalene-1-sulfonate (ANS) binding to BLg indicated that at pH 2.0 the recovery of center of spectral mass or ANS fluorescence was almost complete upon pressure release. No difference in (1)H NMR spectra was observed between pressurized and unpressurized BLg. In addition, NMR detection of the H/D exchange of aromatic protein indicated that the conformation of the vicinity of tryptophan residues could be refolded almost completely after release of pressure. These results seemingly confirm that the pressure-induced denaturation of BLg at pH 2.0 is reversible. However, cis-parinaric acid binding ability of pressurized BLg was largely lost, although its retinol binding ability was the same as its unpressurized one. Furthermore, CD spectra of the far-UV region and 2D NMR spectra evidently revealed the difference in the conformation of the molecule between unpressurized and pressurized BLg. These results are interpreted as an existence of partially fragile structure in the BLg molecule by high pressure.

Circular Dichroism↗
PubMed2001

Systemic administration of immunostimulatory DNA sequences mediates reversible inhibition of Th2 responses in a mouse model of asthma.

This study investigated whether immunostimulatory DNA sequences (ISS) induce a transient or sustained inhibition of Th2 responses to inhaled antigen. We sensitized mice with subcutaneous injections to develop a Th2 response to ovalbumin (ova) and then administered a dose of ISS prior to ova inhalation challenge. Mice were then rechallenged with ova by inhalation a second time at varying time points after the first ova inhalation (1 to 8 weeks later) to determine whether the ISS dose administered prior to the first ova inhalation protected against a subsequent second ova inhalation challenge. A single dose of ISS inhibited the Th2 response to the first inhalation of ova antigen, as well as 4 weeks later to the second inhalation of ova. However, ISS did not inhibit a Th2 response to the second inhalation of ova 8 weeks later. The reversible inhibition of Th2 responses at 8 weeks suggests the need for repeated ISS administration at monthly intervals.

Adjuvants, Immunologic↗
PubMed2001

Successful umbilical cord blood transplantation from an unrelated donor for a patient with Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis.

We report a case of a 5-year-old girl with EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH) who underwent cord blood (CB) stem cell transplantation (CBSCT) from an unrelated donor. The patient presented with persistent high-grade fever and hepatosplenomegaly. Because the disease was refractory to immunochemotherapy according to the HLH94 protocol, she received 2.0 x 10(7) CB nucleated cells/kg body weight (BW) after conditioning with BU/CY/etoposide. No acute GVHD developed, using FK506 for prophylaxis. The neutrophil count reached >0.5 x 10(9)/l by day 21 and the platelet count reached >50 x 10(9)/l by day 84. The patient recovered well with sequelae of neurological deficits more than 10 months after receiving CBSCT, without showing evidence of HLH or chronic GVHD. Real-time PCR proved applicable for estimation of the EBV load in PBMC of the patient. We conclude that CBSCT may be indicated for some cases of refractory EBV-HLH, who have no HLA-matched siblings and are therefore dependent on unrelated marrow donors.

Blood Donors↗
PubMed2001

Anti-obesity effects in rodents of dietary teasaponin, a lipase inhibitor.

OBJECTIVE: Based on the inhibitory effects of teasaponin on pancreatic lipase activity in vitro, this study was performed to clarify whether teasaponin prevented obesity induced in mice by a high-fat diet for 11 weeks. DESIGN: For in vitro experiments, assay for the inhibitory effects of teasaponin on pancreatic lipase activity was performed by measuring the rate of release of oleic acid from triolein in an assay system using triolein emulsified with lecithin, gum arabic, Triton X-100 or 4-methylumbelliferyloleate. For in vivo experiments, female ICR mice were fed a high-fat diet with or without 0.5% teasaponin for 11 weeks. RESULTS: Teasaponin competitively inhibited the hydrolysis of triolein emulsified with lecithin, gum arabic, Triton X-100 or 4-methylumbelliferyloleate. Teasaponin inhibited the elevations of plasma triacylglycerol levels 3, 4 and 5 h after oral administration of lipid emulsion containing corn oil. Teasaponin suppressed the increases in body, parametrial adipose tissue weights and diameter in adipose cell size induced by a high-fat diet. Furthermore, feeding a high-fat diet plus teasaponin had no effect on stool frequency and content, but significantly increased triacylglycerol contents in feces as compared to feeding a high-fat diet. CONCLUSIONS: The anti-obesity effects of teasaponin in high-fat diet-treated mice may be partly mediated through delaying the intestinal absorption of dietary fat by inhibiting pancreatic lipase activity.

Animals↗
PubMed2001

The relationship of primary tumor thickness in carcinoma of the tongue to subsequent lymph node metastasis.

OBJECTIVES: To study whether primary tumor thickness of stage I/II tongue carcinoma provides information about subsequent lymph node metastasis. METHODS: Twenty consecutive patients with T1N0M0 or T2N0M0 tongue carcinoma were studied. Primary tumor thickness was measured with post-contrast helical computed tomography or intra-oral sonography. Cervical lymph nodes were evaluated periodically with sonography at intervals of 2-4 weeks. Sensitivity, specificity and accuracy for subsequent metastasis was calculated. RESULTS: Positive sonographic findings appeared in nine nodes of nine patients during this follow-up period. Eleven patients underwent neck dissections, and nine had histopathologically positive nodes. Nine patients had no sonographic findings of metastasis during a minimum follow-up period of 20 months. Primary tumor thickness varied from 3-16 mm. Using 5 mm as a cut-off thickness, the sensitivity, specificity and accuracy for subsequent lymph node metastasis were 64, 100 and 75% respectively. CONCLUSIONS: Patients with stage I/II tongue carcinoma which is more than 5 mm thick are more likely to develop lymph node metastasis.

Carcinoma, Squamous Cell↗
PubMed2001

Complete sequence of the Japanese quail (Coturnix japonica) mitochondrial genome and its genetic relationship with related species.

The Japanese quail (Coturnix japonica; JQ) is one of the domesticated fowl species of Japan. To provide DNA sequence information for examination of its phylogenetic position in the order Galliformes, the complete sequence of the JQ mitochondria was determined. Sequence analysis revealed that the JQ mitochondrial genome is a circular DNA of 16 697 basepairs (bp), which is smaller than the chicken mitochondrial DNA of 16 775 bp, but the genomic structure of JQ mitochondria was the same as that of the chicken. The sequence homologies of all mitochondrial genes including those for 12S and 16S ribosomal RNA (rRNA), between Japanese quail and chicken ranged from 78.0 to 89.9%. Because the sequences of NADH dehydrogenase subunit 2 and cytochrome b genes had been reported in five species [Phasianus colchicus (ring-neck pheasant: RP), Gallus gallus domesticus (chicken: CH), Perdix perdix (grey partridge: GP), Bambusicola thoracia (Chinese bamboo partridge: CP), and Aythya americana (redhead: RH)], the concatenated nucleotide sequences (2184 bp) and amino acid sequences of these two genes were used in a phylogenetic analysis of JQ against these five species using a maximum likelihood (ML) method. Using the first and second bases of the codons, and the third base of the codons indicated a phylogenic tree of [RH, (RP, GP), (JQ, (CH, CP))]. A phylogenic tree of [RH, JQ, (RP, GP), (CH, CP)] was determined using amino acid sequences. Because the local bootstrap values for the JQ branch in these trees are not high, additional sequence is necessary for construction of a reliable tree.

Animals↗
PubMed2001

Aberrant expression of caspase cascade regulatory genes in adult T-cell leukaemia: survivin is an important determinant for prognosis.

Derangement of either apoptosis or cell division is known to play an important role in tumorigenesis. Fas-mediated apoptosis on normal and leukaemic T cells is finely tuned by inhibitory proteins, such as FAP-1, FLIP and survivin, and defective caspase isoform which can attenuate the function of its intact caspase as a decoy molecule. However, complex involvement of such inhibitors in tumour biology relating to apoptotic pathology remains unclear in the neoplasms. We report the aberrant expression of FAP-1, FLIP and survivin mRNAs on leukaemic T cells from adult T-cell leukaemia (ATL) patients. Among these inhibitors, only survivin was aberrantly expressed in all ATL cases, but not in any normal peripheral blood mononuclear cells (PBMCs). Furthermore, survivin mRNA expression level was characteristic in each subtype of ATL and represented an important determinant for ATL prognosis. However, the apoptotic effector of casp-8, which is essential in Fas-mediated signal transduction, was dominant in defective casp-8 rather than intact casp-8 in ATL cells, suggesting a favourable biological situation for escape from apoptosis. Taken together, ATL cells probably possess many different regulatory mechanisms in order to attenuate Fas-mediated signalling and subsequently expand their populations under escape from apoptosis. Among these inhibitors, survivin is a useful bio-marker to assess tumour biology and may be a potential new target for apoptosis-based selective therapy in neoplasms as the expression is a general feature of neoplasia, but not normal tissues.

Apoptosis↗
PubMed2001

Possible involvement of IL-12 in reovirus type-2-induced diabetes in newborn DBA/1 mice.

This study extends our previous observations that the reovirus type-2(Reo-2) can induce autoimmune insulitis, which may be mediated by T-helper (Th) 1-dependent mechanisms, resulting in diabetes in newborn DBA/1 mice. In this study mRNA expression for Th1-related cytokines including Th1 and Th2 cytokines in splenic cells was examined by reverse transcriptase polymerase chain reaction (RT-PCR) in relation to the development of insulitis. Furthermore, the effect of monoclonal antibody (MoAb) against interleukin (IL)-12(p40) on the development of insulitis and the mRNA expression in the splenic cells was examined. The mRNA expression for IL-12(p40), IL-18, and interferon (IFN)-gamma, but not IL-5, increased in the spleen in parallel with the development of insulitis. The treatment with MoAb to IL-12(p40) reduced the insulitis with diabetes which was associated with a decrease in the mRNA expression for IL-12(p40), IL-18 and IFN-gamma, and an increase of IL-4 mRNA expression in the spleen. The present study suggested that Th1-dominant systemic immune responses, being responsible for the development of autoimmune insulitis, might be induced by IL-12-induced and IL-18-activated mechanisms.

Animals↗
PubMed2001

Expression of aquaporins 7 and 8 in the developing rat testis.

Aquaporin (AQP) is a molecule that facilitates water permeability through cell membranes and is widely distributed in the mammalian body. Among members of the AQP family, AQP7 and AQP8 are predominantly expressed in the testis. This paper examined the expression of these two AQPs in the developing rat testis, using northern blot and immunohistochemistry to visualize their roles during the progression of spermatogenesis in the developing testis. In adult rats, expression of AQP7 was localized to spermatids, whereas AQP8 protein was observed in spermatocytes. In the developing testis, transcripts of AQP7 became detectable between 23 and 25 days post-partum, when round spermatids have been reported to appear. On the other hand, AQP8 mRNA was first detected between 13 and 16 days post-partum, consistent with the reported first appearance of spermatocytes (13-14 days). AQP7 and AQP8 proteins were detectable at 28 days post-partum. The results suggest that AQP7 and AQP8 appear in the testis in accordance with the maturation of germ cells, and are involved in spermatogenesis.

Aging↗
PubMed2001

Left-right asymmetry in Drosophila melanogaster gut development.

While left-right (LR) asymmetric morphogenesis is common to various animal species, there have been no systematic studies of the LR asymmetry of body structures of Drosophila melanogaster. In the present paper the LR asymmetric development of the Drosophila gut is described, in which three major parts, the foregut, midgut and hindgut, show almost invariant LR asymmetry. The asymmetry is generated by a twist of each part in particular orientations, resulting in a left-handed (sinistral) convolution as a whole. The frequency of spontaneous reversal of LR orientations is very low (< 0.6%) and reversal of each part of the gut occurs independently. The bicoid mutation causes duplication of the posterior half of the gut, essentially keeping the left-handed twist, suggesting that the LR asymmetry may depend on some intrinsic nature of the cells or tissues rather than a graded distribution of morphogens in the egg. The handedness of particular gut parts was randomized or became symmetric in mutants of brachyenteron, huckebein and patched, suggesting that different gene pathways can interfere in determining LR asymmetry of the gut. It is noteworthy that all of these genes are expressed LR symmetrically.

Animals↗