Biomedical subjects

K Uchida

Publications and source records attributed to K Uchida.

At least 505 records · Page 28Linked to original sources

PubMed1997

Integration of HTLV-1 provirus into mouse transforming growth factor-alpha gene.

Human T cell leukemia virus type 1 (HTLV-1) provirus integration was investigated in mice inoculated with MT-2 cells, a HTLV-1 producing human T-cell line. From spleen DNA derived from a MT-2 cell-injected mouse, we cloned a HTLV-1 integration site by ligation-mediated PCR. The nucleotide sequence showed that HTLV-1 provirus was integrated into an intron of the mouse transforming growth factor-alpha gene in the reverse orientation. This result provides for the first time molecular evidence that mice can be infected with HTLV-1.

Amino Acid Sequence↗

PubMed1997

Machado-Joseph disease gene product identified in lymphocytes and brain.

Machado-Joseph disease (MJD) is associated with the expansion of an unstable CAG repeat. The existence of an abnormal gene product in MJD was previously suggested with the expanded polyglutamine stretch-specific antibody. However, the product of the normal allele has not previously been identified. We generated monoclonal antibodies against the fusion protein (codon 225-310) of the MJD gene product and then identified the MJD1 gene product in normal lymphoblastoid cells as a approximately 50-kDa protein by immunoblot analysis. The electrophoretic mobility differences among the normal allele products corresponds to the molecular size difference produced by the polyglutamine stretch and the polymorphism at the C-terminus. Moreover, abnormal immunoreactive bands which were larger than the normal ones were found as a approximately 60-kDa protein exclusively in the MJD samples. The cytoplasm and the nuclei of neurons and glial cells were stained by these antibodies with immunocytochemistry. As in other CAG repeat diseases, the abnormal and normal allele products were almost equally expressed in lymphoblastoid cells and the brain of MJD patients.

Alleles↗

PubMed1997

Cloning and sequencing of the gene encoding the plasma membrane H(+)-ATPase from an acidophilic red alga, Cyanidium caldarium.

A cDNA containing an open reading frame encoding the putative plasma membrane H(+)-ATPase in an acidophilic red alga, Cyanidium caldarium, was cloned and sequenced by means of PCR and Southern hybridization based on homologous sequences of P-type ATPases found in other organisms. The cloned cDNA is 3300 bp in length, containing a 2865 bp open reading frame encoding a polypeptide of 955 amino acids which has a predicted molecular mass of 105,371. The deduced amino acid sequence was found to be more homologous to those of P-type H(+)-ATPases from higher plants than that from the green alga Dunaliella bioculata.

Amino Acid Sequence↗

PubMed1997

Oxidative stress is found in amyloid deposits in systemic amyloidosis.

Oxidative stress in human amyloid deposits from patients with systemic amyloidosis, such as familial amyloidotic polyneuropathy (FAP), primary amyloidosis, and secondary amyloidosis, was examined immunohistochemically by means of an affinity purified anti-hydroxynonenal (HNE) antibody to HNE, a marker of lipid peroxidation. Furthermore, the levels of thiobarbituric acid reactive substances (TBARS), which is another marker of lipid peroxidation, and the levels of protein carbonyl, a maker of protein modifications by free radicals, were determined in FAP patients and healthy controls. Affinity purified anti-HNE antibody reacted with amyloid deposits in all types of amyloid tissues examined. Significantly higher levels of TBARS and protein carbonyl were found in amyloid rich tissues of FAP patients compared with those in the control subjects. These results verify that lipid peroxidation via free radical injury occurs in amyloid deposits in systemic amyloidosis. The protein modifying properties of free radicals increase the likelihood that they play an important role in the amyloid formation process.

Adult↗

PubMed1997

Specific species of intestinal bacteria influence the induction of aberrant crypt foci by 1,2-dimethylhydrazine in rats.

To shed light on the association of intestinal microflora with the development of colon cancer, we studied the modifying effects of intestinal microflora on the occurrence of 1,2-dimethylhydrazine (DMH)-induced colonic aberrant crypt foci (ACF) in germfree (GF), gnotobiotic (GB) and conventionalized (Cvd) rats. In the first part of this study, 10 week old germfree Fischer-344 rats were randomly assigned to three groups and two groups of rats were orally inoculated with mixtures of pure culture of Escherichia coli, Enterococcus faecium, and several strains of Bacteroides and Clostridium species (GB), or feces from conventional rats (Cvd). Inoculated rats were given two weekly i.p. injections of DMH (20 mg/kg body wt) at 13 and 14 weeks of age. Rats were sacrificed 11 or 34 weeks after the last DMH injection for ACF scoring. The total number of ACF, ACF with four or more crypts/focus, and mean number of aberrant crypts per focus (crypt multiplicity) in GB rats sacrificed at week 34 were 168% (P < 0.001), 442% (P < 0.001) and 138% (P < 0.001) of those in GF rats, respectively. On the other hand, the same values in Cvd rats were 42% (P < 0.001), 147% (P = 0.246) and 159% (P < 0.001) of those in GF rats, respectively. Similar results were observed in rats that were sacrificed at week 11. In the second part of this study, the effect of colonization of Bifidobacterium breve on the ACF profiles was examined in GB rats. The number of ACF with four or more crypts/focus and crypt multiplicity in GB plus B. breve rats at week 11 were significantly lower than those of GB rats (P < 0.01, and P < 0.05, respectively), although the former was not statistically significant at week 34. These findings suggest that some intestinal bacteria might behave as promoters and some as anti-promoters in colon carcinogenesis.

1,2-Dimethylhydrazine↗

PubMed1997

Inhibition of tumor necrosis factor-alpha production retards liver regeneration after partial hepatectomy in rats.

We studied the effects of a tumor necrosis factor-alpha (TNF-alpha) production inhibitor E3330, [(2E)-3-[5-(2,3-dimethoxy-6-methyl-1,4-benzoquinolyl)]-2-nonyl-2-+ ++propenoic acid] on liver regeneration in rats subjected to 70% partial hepatectomy. The BrdU labeling index was 53.5 +/- 3.8% 24 h after partial hepatectomy alone and was significantly inhibited by E3330 (25 and 50 mg/ kg) in a dose-dependent manner (43.3 +/- 2.1% and 19.0 +/- 10.3%, respectively; p < 0.05, p < 0.01). In these 3 groups, TNF-alpha protein levels in liver tissue were 187 +/- 18, 123 +/- 47, and 89 +/- 33 pg/mg total protein, respectively, with a significant decrease by E3330 administration (p < 0.01). TNF-alpha mRNA expression in liver tissue was also reduced by E3330. These results suggest that TNF-alpha promotes liver regeneration after partial hepatectomy.

Alanine Transaminase↗

PubMed1997

Comparison of the autogenous potentials of newly-emerged anautogenous female mosquitoes.

The autogenous potentials in several species of newly emerged anautogenous female mosquitoes were examined by homoplastic transplantion of resting stage ovaries into newly-emerged females. Ovaries from 4-day-old female Culex pipiens quinquefasciatus, with follicles at stage Ib, were all activated in the newly emerged hosts and deposited some yolk in the oocyte. In addition, some of the implants (5-10%) matured. Transplanted C. tritaeniorhynchus ovaries also started to develop beyond the Ib resting stage, but never grew beyond the IIb stage. Resting Armigeres subalbatus and Aedes albopictus ovaries, both follicles having already reached the IIa-IIb stages, did not show any further growth after being implanted into newly emerged hosts. However, resting Ae. albopictus ovaries matured when heteroplastically transplanted into Culex pipiens molestus (74%) or into Culex pipiens pallens (5%). In addition, Ae. albopictus females, acting as hosts, could mature transplanted C. p. molestus (23%) and C. p. pallens ovaries (10%). Thus, the above specific differences in autogenous potentials seem to reside not only in the internal environment of the hosts, but also in the ovaries themselves. Development of the host ovaries in the above homoplastic and heteroplastic transplantations were usually suppressed by the implanted donor ovaries and failed to reach the resting stages of each species.

Journal Article↗

PubMed1997

Amyloid beta-peptide impairs glucose transport in hippocampal and cortical neurons: involvement of membrane lipid peroxidation.

A deficit in glucose uptake and a deposition of amyloid beta-peptide (A beta) each occur in vulnerable brain regions in Alzheimer's disease (AD). It is not known whether mechanistic links exist between A beta deposition and impaired glucose transport. We now report that A beta impairs glucose transport in cultured rat hippocampal and cortical neurons by a mechanism involving membrane lipid peroxidation. A beta impaired 3H-deoxy-glucose transport in a concentration-dependent manner and with a time course preceding neurodegeneration. The decrease in glucose transport was followed by a decrease in cellular ATP levels. Impairment of glucose transport, ATP depletion, and cell death were each prevented in cultures pretreated with antioxidants. Exposure to FeSO4, an established inducer of lipid peroxidation, also impaired glucose transport. Immunoprecipitation and Western blot analyses showed that exposure of cultures to A beta induced conjugation of 4-hydroxynonenal (HNE), an aldehydic product of lipid peroxidation, to the neuronal glucose transport protein GLUT3. HNE induced a concentration-dependent impairment of glucose transport and subsequent ATP depletion. Impaired glucose transport was not caused by a decreased energy demand in the neurons, because ouabain, which inhibits Na+/K(+)-ATPase activity and thereby reduces neuronal ATP hydrolysis rate, had little or no effect on glucose transport. Collectively, the data demonstrate that lipid peroxidation mediates A beta-induced impairment of glucose transport in neurons and suggest that this action of A beta may contribute to decreased glucose uptake and neuronal degeneration in AD.

Adenosine Triphosphate↗

PubMed1997

Effect of gene therapy with the herpes simplex virus-thymidine kinase gene on hepatic metastasis in murine colon cancer.

Hepatic metastasis of colon cancer is an important prognostic factor for survival. In this study, we examined the effect of gene therapy using the herpes simplex virus-thymidine kinase (HS-tk) gene with short-course ganciclovir (GCV) treatment for multiple hepatic metastases of murine colon cancer. Colon26 cells transfected with the HS-tk gene were found to be sensitive to GCV in a concentration-dependent way. On the other hand, induction of the HS-tk gene in the cells had no influence on cell growth in vitro. However, multiple hepatic metastases of Colon26 cells transfected with HS-tk gene were significantly suppressed by the GCV treatment. These results thus suggest that HS-tk gene therapy is useful for the treatment of hepatic metastasis in colon cancer.

Animals↗

PubMed1997

Cyclosporine A inhibits interleukin-8 production in a human colon epithelial cell line (HT-29).

Intestinal epithelial cells produce various inflammatory mediators. However, the way in which immunosuppressive agents influence the production of these mediators by intestinal epithelial cells is not understood. The effects of cyclosporine A (CsA), tacrolimus (FK506), and dexamethasone (DEX) on cytokine-induced production of interleukin (IL)-8 in a human colonic cancer cell line (HT-29) were examined. HT-29 cells were stimulated with either IL-1 beta or tumor necrosis factor alpha (TNF alpha) together with CsA, FK506, or DEX. The presence of IL-8 protein was detected by enzyme-linked immunosorbent assay, and the expression of IL-8 messenger RNA (mRNA) by reversetranscription polymerase chain reaction. CsA (1, 5, and 10ng/ml) significantly reduced IL-1 beta-induced IL-8 production (by 32%, 41%, and 48%, respectively), and reduced TNF alpha-induced IL-8 production (by 21%, 42%, and 50%, respectively). FK506 or DEX had no effect on IL-1 beta- or TNF alpha-induced IL-8 production. The expression of IL-8 mRNA was also inhibited by CsA. These findings suggest that CsA may influence the production of inflammatory mediators in colonic cells in a different manner from FK506 and DEX.

Cell Count↗

PubMed1997

Vertebral lesions associated with palmoplantar pustulosis.

Spinal lesions were reviewed in 9 patients (3 men and 6 women) who presented with palmoplantar pustulosis. Cervical lesions were found in 3 patients and lumbosacral involvement in 7. The duration of disease averaged 4.8 years. Seven patients had associated sterno-costo-clavicular hyperostotic lesions, and all showed abnormalities in blood tests which suggested chronic inflammation. Vertebral lesions were assessed as a spondylodiscitis type in 4, single level syndesmophyte-forming type in 1, multiple hyperostosis type in 4, and an ivory vertebra type in 1. Five patients were treated conservatively, and 4 with progressive spondylodiscitis type lesions underwent curettage and anterior interbody fusions. At follow-up, all patients improved in both spinal and cutaneous presentations, and 4 who underwent surgery and 1 with tonsillectomy attained complete cure. The vertebral manifestations of palmoplantar pustulosis may vary, but rapidly progressive lesions need surgery for favourable early improvement from the vertebro-cutaneous symptom complex.

Female↗

PubMed1997

Immunohistochemical study of constituents other than beta-protein in canine senile plaques and cerebral amyloid angiopathy.

To clarify the significance of the constituents of canine senile plaques (SPs) or cerebrovascular amyloid deposits, paraffin and cryostat sections of canine brains were examined by immunohistochemistry using antibodies against cathepsin B (CB), cathepsin D (CD), cystatin C (CC), alpha-1-antichymotrypsin (ACT), heat shock protein 70 (HSP70), ubiquitin (Ubq), and apolipoprotein E (Apo E). On the cryostat sections, all types of canine SPs and cerebrovascular amyloid deposits in both arterioles and capillaries were positive for Apo E. On paraffin sections, the Apo E immunoreactivity of diffuse plaques was weak and varied according to the method of fixation or pretreatment before immunostaining. Moreover, amyloid plaques were found to contain several elements that were positive for CC, ACT, CD, and Ubq, and a subset of vascular amyloid deposits around cortical capillaries showed significant immunoreactivity for CD, CC, and ACT. In addition, vascular amyloid deposits in the arterioles showed moderate CD immunoreactivity and were intensely Apo E positive. No significant labeling of canine Sps or vascular amyloid deposits was detected when the antibodies against CB and HSP 70 were applied to the cryostat and paraffin sections. These results indicated that, of the constituents examined, Apo E might be most closely related to canine beta-amyloidosis in the early stage of this brain disorder.

Amyloid beta-Peptides↗

PubMed1997

Three-dimensional topographic analysis of spinal accessory motoneurons under chronic mechanical compression: an experimental study in the mouse.

We investigated the effect of chronic mechanical compression of the cervical spinal cord on the number of spinal accessory motoneurons in 25 tiptoe-walking Yoshimura mice. The animals had calcified deposits in the atlantoaxial membrane at the C1-C2 vertebral level, compressing the spinal cord posterolaterally. Motoneurons of the spinal accessory nerve between C1 and C5 segments were labelled using wheat germ agglutinin-horseradish peroxidase (WGA-HRP) injected into the sternocleidomastoid muscles. The counted cells were processed into a three-dimensional computer display to analyse the cytoarchitectonic changes caused by external cord compression. The number of WGA-HRP-labelled spinal accessory motoneurons was significantly reduced on the affected side. The number of motoneurons in compromised C2 and C3 cord segments correlated linearly with the extent of mechanical compression, but no such relationship was present on the contralateral side. There was an increase in the number of WGA-HRP-labelled spinal accessory motoneurons in the medial cell pools of the anterior grey horn at a level most rostral to the compression, and in the ventrolateral cell pools at levels immediately rostral to the compression. Our findings suggest that the spinal accessory motoneurons translocate rostral to the area of external compression in order to avoid mechanical injury.

Animals↗

PubMed1997

Plasticity of the spinal cord contributes to neurological improvement after treatment by cervical decompression. A magnetic resonance imaging study.

To investigate the relationship between morphological plasticity of the spinal cord and neurological outcome after surgery for compressive lesions, we correlated the transverse area of the cervical spinal cord measured by transaxial magnetic resonance imaging (MRI) obtained during the early postoperative period (1-6 months) with neurological function assessed at a median postoperative follow-up period of 2.5 years. Measurements on MRI in 56 patients (35 men and 21 women) included evaluation of the cross-sectional area of the cervical cord and the subarachnoidal space at the level of decompression. The transverse area of the cervical cord increased by 30 to 62% postoperatively and that of the subarachnoidal space by 57 to 95%. Neurological improvement was noted in all patients and averaged 63% in our assessment scale. Expansion of the cervical cord during the early postoperative period correlated significantly with the late postoperative neurological status (P = 0.009). Our results suggest that an increase in the cross-sectional area of the cervical spinal cord, representing spinal cord morphological plasticity, is a significant factor in determining the late neurological improvement following decompressive surgery.

Adult↗

PubMed1997

Bile acid metabolism in young-old parabiotic rats.

Serum cholesterol, triglyceride and phospholipid levels, liver cholesterol concentration, bile flow, biliary cholesterol, phospholipid and bile acid secretion rates, fecal sterol and bile acid levels and their bile acid compositions were examined in young-old parabiotic rats and compared with those in young and old control rats and young-young parabiotic rats. Bile acid composition was expressed in terms of the cholic acid group/chenodeoxycholic acid group (CA/CDCA) ratio. Body weight (BW) gain decreased after parabiosis especially in old rats, but the liver weight (g/100 g BW), diet-intake, feces dry weight, liver cholesterol concentration and fecal sterol level were almost the same in all the groups. The biliary bile acid secretion rate was higher and the fecal bile acid level was lower in old rats than those in young rats but both the levels became comparable with those in young rats after parabiosis of old rats with young rats. Young rats, however, showed no changes in these levels after parabiosis. The serum cholesterol level and the biliary and fecal CA/CDCA ratios in old rats were higher than those in young rats but decreased after parabiosis with young rats, although they were still higher than those in young rats. The serum cholesterol level in young rats increased after parabiosis with old rats, but not after parabiosis with young rats, and the fecal bile acid level and the CA/CDCA ratio were not changed in either case. It is concluded from these findings that the serum cholesterol level and the CA/CDCA ratio increased with age and that these increases were prevented after parabiosis with young rats while young rats, although their serum cholesterol level was increased, showed no increase in the CA/CDCA ratio after parabiosis with old rats.

Aging↗

PubMed1997

Aortic blood momentum--the more the better for the ejecting heart in vivo?

OBJECTIVES: The aim of the present study was to test two hypotheses: (1) the momentum of the blood flowing out of the left ventricle toward the aorta (inertia force) plays an important role in the initiation of decay and the maximum rate of decay (peak (-dP/dt)) of left ventricular pressure (P); (2) a normal heart itself generates the inertia force which enhances its function. METHODS: The contribution of the inertia force to (-dP/dt) was theoretically given as rho c alpha, where rho is the blood density, c the pulse wave velocity, and alpha the deceleration rate of aortic blood flow. The correlations of peak (-dP/dt) with rho c alpha and with the time constant (tau) of the pressure decay during isovolumic relaxation, which was considered to represent myocardial relaxation characteristics, were compared in seven dogs. We developed a method of grading the strength of the inertia force, using the phase loop of left ventricular pressure (dP/dt vs. P relation). The method was applied to the records of 25 patients with ischemic heart disease, from which high fidelity left ventricular pressure recordings were available. RESULTS: The correlation of peak (-dP/dt) with rho c alpha was much higher than with tau (0.75 vs. -0.46). 16 of the 25 patients showed evidence of the inertia force. However, other patients showed no inertia force. The strength of the inertia force showed a significant (P < 0.05) correlation with left ventricular end-diastolic pressure (r = -0.46), cardiac index (r = 0.62), stroke volume index (r = 0.69), ejection fraction (r = 0.46), and peak (-dP/dt) (r = 0.56). CONCLUSION: The inertia force of late systolic aortic flow contributed to ventricular relaxation in the normal heart.

Aged↗

PubMed1997

Anti-mitogenic effects of sarpogrelate in cultured rat mesangial cells.

We investigated the effects of the new 5-HT2A receptor antagonist, sarpogrelate, on DNA synthesis in renal mesangial cells stimulated with 5-HT in the presence and absence of platelet-derived growth factor (PDGF)-BB. Both 5-HT and PDGF-BB demonstrated a mitogenic effect on these cells. When mesangial cells were incubated in the absence of PDGF-BB, sarpogrelate inhibited DNA synthesis in these cells in a dose-dependent manner. In the presence of PDGF-BB, sarpogrelate had a weaker anti-mitogenic effect in mesangial cells stimulated with 5-HT. Sarpogrelate was cytotoxic at concentrations over 10(-5) M according to the results of LDH release assays, and it reduced the S1 phase in mesangial cells stimulated with 5-HT by a flow cytometry. These findings suggest that sarpogrelate may be effective in the treatment of some glomerulonephritis associated with mesangial cell proliferation.

Animals↗

PubMed1997

Absolute and spectral sensitivities in dark- and light-adapted Pagothenia borchgrevinki, an Antarctic nototheniid fish.

Functional properties of the retina of Pagothenia borchgrevinki, an Antarctic nototheniid fish that lives beneath the 2.5-3 m thick sea-ice in water of -1.8 degrees C temperature, were analyzed electrophysiologically at Scott Base (77 degrees 50'S; 166 degrees 45'E). The waveform of the ERG was monophasic in the dark-adapted state and showed an off-response of opposite polarity in the light-adapted condition. Responses of the light-adapted retina were smaller than those of the dark-adapted eye, although both photopic and scotopic components were observed. Spectral sensitivity measured by monochromatic photostimulation at 14 different wavelengths across the 400-700-nm range showed a single maximum at 490 nm. The spectral sensitivity curve is consistent with a rhodopsin photopigment. The dark-adapted retina exhibited a photon flux density threshold of approximately 2 x 10(9) photons cm-2 s-1) when monochromatic flashes of 500 nm wavelength and 250 ms duration were used. When the stimulus consisted of 1 s white light, a minimum energy flux density of approx. 2 x 10(-4) microW/cm2 was necessary to elicit a detectable response. It was concluded that the visual system of P. borchgrevinki was in tune with the dominant downwelling spectral irradiance and that, due to retinal thermal noise reduction in the cold environment, no great need for particular anatomical adaptations to further enhance sensitivity existed.

Acclimatization↗