Search PubMed⌕ Search

Biomedical subjects

T Kikuchi

Publications and source records attributed to T Kikuchi.

At least 73 records · Page 4Linked to original sources
PubMed2001

Caveolae in mesangial cells and caveolin expression in mesangial proliferative glomerulonephritis.

BACKGROUND: Caveolae are plasma membrane invaginations that have a diameter of 40 to 60 nm. Recent evidences have demonstrated that caveolae contain a variety of signal transduction molecules. Caveolin is a marker protein of caveolae and has been proposed to play a negative regulatory role in signal transduction. The aim of this study was to investigate the behavior of caveolae and caveolin in experimental glomerulonephritis, the localization of both platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-beta) receptors in the caveolae membrane, and the regulation of caveolin expression in cultured mesangial cells. METHODS: The expression of caveolin-1 was examined by immunoblotting and immunohistology using anti-caveolin antibody in anti-Thy-1 nephritis. The caveolae membrane fraction of mesangial cells was isolated by sucrose gradient method and expression of PDGF receptor and TGF-beta receptor were detected by immunoblotting. The effects of mitogens such as phorbol 12-myristate 13-acetate (PMA) and PDGF on the expression of caveolin-1 protein and mRNA were also examined in cultured mesangial cells. RESULTS: Caveolin-1 was mainly expressed in glomeruli and was significantly up-regulated in anti-Thy-1 nephritis rat kidney. In cultured mesangial cells, the membrane invaginations of caveolae were revealed by electron microscopy. PDGF receptors abounded in the caveolae membrane and rapidly changed their subcellular distribution after ligand stimulation. In contrast, TGF-beta receptors abounded in the non-caveolae membrane and did not change after ligand stimulation. Decreases in caveolin-1 protein, which were associated with increases in mRNA expression after the exposure of PMA or PDGF-BB, suggested an increased turnover of caveolin-1 in mesangial cells stimulated by mitogens. CONCLUSION: To our knowledge, this electron microscopical study is the first to demonstrate the presence of caveolae in cultured mesangial cells. Caveolae integrate PDGF receptors, and caveolin-1 may play a role in the pathogenesis of the mesangial proliferative glomerular diseases through PDGF signaling.

Animals↗
PubMed2001

Effects of high molecular weight hyaluronan on the distribution and movement of proteoglycan around chondrocytes cultured in alginate beads.

OBJECTIVE: To evaluate the effects of high molecular weight hyaluronan (HA) on the distribution and movement of proteoglycan (PG) formed around rabbit chondrocytes cultured in alginate beads. DESIGN: Rooster comb-derived HA (MW 8x10(5) Da) was co-polymerized in alginate gel to study the direct effects of extrinsic HA on chondrocytes. PG metabolism of rabbit chondrocytes cultured in alginate beads was examined by measuring the incorporation of [(35)S]sulfate into glycosaminoglycan in two distinct regions, the cells with their cell-associated matrix (CM) and the further-removed matrix (FRM). Immunohistochemical analysis was performed using monoclonal antibodies against chondroitin sulfate and keratan sulfate. Autoradiography using degenerated cartilage tissue from the rabbit osteoarthritis (OA) model was performed to discover the effect of HA on the distribution of newly-synthesized PG in the cartilage tissue. RESULTS: The incorporation of [(35)S]sulfate into newly-synthesized PG in the cells with CM decreased with the addition of 0.125-1.0 mg/ml HA, while the incorporation in the FRM increased. These effects of HA on the distribution of newly-synthesized PG were the same either in chondrocytes with CM or chondrocytes without CM. Immunohistochemical analysis showed that staining of PG in the CM was decreased and staining in the FRM was increased in the HA treated group compared to the control group. Autoradiography using degenerated cartilage tissue from the rabbit OA model indicated that [(35)S]-labeled macromolecules showed a more diffuse distribution in the HA treated group compared with the control group. CONCLUSION: These results indicate that extrinsic HA could affect the movement of newly-synthesized PG from the CM to the FRM in both alginate beads and cartilage tissue.

Adjuvants, Immunologic↗
PubMed2001

Lack of association between the hKCa3 gene and Japanese schizophrenia patients.

Several researchers have suggested an association between large numbers of CAG repeats in the hKCa3 gene and schizophrenia. However, these reports remain inconclusive and require further investigation. We tried to replicate these results in 112 Japanese schizophrenia patients and 102 control subjects of highly matched age and sex by applying an allele dichotomization model. No association was found. The overall distributions of allele frequencies were not significantly different between schizophrenic patients and normal control subjects. In addition, we tested the association between the size of the CAG repeats and the scores on three dimensions (positive and negative symptoms, and disorganization), but no significant results were obtained. Our results do not support the involvement of the hKCa3 gene in schizophrenia, at least in the Japanese population.

Adult↗
PubMed2001

Protection against pulmonary infection with Pseudomonas aeruginosa following immunization with P. aeruginosa-pulsed dendritic cells.

To develop a Pseudomonas aeruginosa vaccine that allows the host immune system to select the antigens, we hypothesized that dendritic cells (DC) pulsed with P. aeruginosa would induce protective immunity against pulmonary infections with P. aeruginosa. Incubation of murine bone marrow-derived DC with P. aeruginosa in vitro led to uptake of P. aeruginosa and activation of the DC. Spleen-derived CD4(+) cells from mice immunized with P. aeruginosa-pulsed DC showed increased proliferation, demonstrating that DC pulsed with P. aeruginosa were capable of eliciting a P. aeruginosa-specific immune response. To evaluate if P. aeruginosa-pulsed DC can induce protective immunity against P. aeruginosa pulmonary infection, DC incubated with P. aeruginosa in vitro were administered systemically to syngeneic mice, and the mice were then challenged by intrapulmonary infection with P. aeruginosa (5 x 10(4) CFU/mouse) 13 days later. Unimmunized control mice and mice who had previously received naive DC or DC stimulated with lipopolysaccharide or Escherichia coli died within 72 h. In contrast, 45% of mice receiving P. aeruginosa-pulsed DC demonstrated prolonged survival (>14 days). Finally, DC-pulsed with heat-inactivated P. aeruginosa protected CD8(-/-) but not CD4(-/-) mice, demonstrating that CD4(+) T cells were required for the DC pulsed with P. aeruginosa to induce protective immunity.

Animals↗
PubMed2001

Macrophage- and neutrophil-dominant arthritis in human IL-1 alpha transgenic mice.

To study the effects of IL-1 alpha in arthritis, we generated human IL-1 alpha (hIL-1 alpha). Transgenic mice expressed hIL-1 alpha mRNA in various organs, had high serum levels of hIL-1 alpha, and developed a severe polyarthritic phenotype at 4 weeks of age. Not only bone marrow cells but also synoviocytes from knee joints produced biologically active hIL-1 alpha. Synovitis started 2 weeks after birth, and 8-week-old mice showed hyperplasia of the synovial lining layer, the formation of hyperplastic synovium (pannus) and, ultimately, destruction of cartilage. Hyperplasia of the synovial lining was due to the accumulation of macrophage-like cells expressing F4/80 molecules. hIL-1 alpha was widely distributed in macrophage- and fibroblast-like cells of the synovial lining cells, as well as synovial fluid monocytes. T and B cells were rare in the synovial fluid, and analysis of marker expression suggests that synoviocytes were directly histolytic and did not act as antigen-presenting cells. In the joints of these mice, we found elevated levels of cells of the monocyte/macrophage and granulocyte lineages and of polymorphonuclear neutrophils (PMNs), most of which expressed Gr-1, indicating that they were mature, tissue-degrading PMNS: Cultured synoviocytes and PMNs from these animals overexpress GM-CSF, suggesting that the hematopoietic changes induced by IL-1 and the consequent PMN activation and joint destruction are mediated by this cytokine.

Animals↗
PubMed2001

Antigen-pulsed dendritic cells expressing macrophage-derived chemokine elicit Th2 responses and promote specific humoral immunity.

Macrophage-derived chemokine (MDC) is a potent chemoattractant for antigen-specific T lymphocytes. We hypothesized that Adenovirus- (Ad-) transduced dendritic cells (DCs) overexpressing MDC would enhance the T cell-mediated humoral immune response specific for antigens presented by the DC. We challenged two strains of mice with lethal Pseudomonas aeruginosa infection 3 weeks after immunization with AdMDC-modified DCs pulsed with heat-killed P. aeruginosa. MDC-expressing DCs specifically attracted T lymphocytes and preserved typical DC surface phenotypes without growth factors in vitro. Mice immunized with AdMDC/Pseudomonas/DCs developed high levels of serum anti-Pseudomonas Ab's and were protected from a lethal respiratory challenge with Pseudomonas. The in vivo protective immunity required CD4(+) T cells, B cells, and IL-4, but not CD8(+) T cells and IL-12. AdMDC/DCs pulsed with Pseudomonas yielded significant but not absolute cross-protection against different strains of P. aeruginosa. Pseudomonas-pulsed AdMDC/DCs protected mice from Pseudomonas but not Escherichia coli and vice versa; this microbe-specific protection correlated with microbe-specific induction of CD4(+) T cell proliferation and IL-4 secretion. Based on these observations, AdMDC-modified DCs pulsed with a killed bacteria may be a useful approach to vaccination against infectious disorders.

Adenoviridae↗
PubMed2001

Effect of whole-body x-irradiation on antigen-induced airway response in sensitized guinea pigs.

The objectives of this study were to test the hypothesis that x-irradiation inhibits the late asthmatic response (LAR) without influencing the early asthmatic response (EAR) and to examine the mechanism of the inhibitory effect. Twenty sensitized guinea pigs were irradiated at a dose of 8 Gy. The next day, one-half of the animals were injected intravenously with spleen cells (2 x 10(8)) collected from unirradiated sensitized guinea pigs, whilst the other half were injected with vehicle only. Ten additional unirradiated sensitized guinea pigs also received vehicle only. Antigen inhalation challenge took place two days later. Pulmonary resistance was measured for 6 h after antigen exposure, and bronchoalveolar lavage and lung fixation were then undertaken. The area under the percentage pulmonary resistance curve 2-6 h after allergen inhalation was used for analysis of the LAR, while the maximal percentage change in pulmonary resistance was used for analysis of the EAR. Irradiation abolished the LAR (364.4+/-49.4 versus 62.8+/-10.4) without inhibiting the EAR (229.3+/-27.2 versus 278.7+/-40.2) and significantly inhibited the accumulation of eosinophils and lymphocytes in the airways. Transfer of spleen cells restored the LAR (334.4+/-66.8) and the recruitment of cells to the levels seen in unirradiated sensitized guinea pigs. In addition, transfer of only CD4+ T-lymphocytes separated from the spleen cells restored the LAR (439.4+/-62.1) and the cell infiltration into the airways. These inhibitory effects of x-irradiation were due to decreases in numbers of CD4+ T-lymphocytes.

Airway Resistance↗
PubMed2001

Quantitative and specific detection of a trichloroethylene-degrading methanotroph, Methylocystis sp. strain M, by a most probable number-polymerase chain reaction method.

We developed a rapid and specific enumeration method for a trichloroethylene-degrading methanotroph, Methylocystis sp. strain M, based on a most probable number-polymerase chain reaction method for monitoring the bacterium at bioremediation sites. The primers designed for the mmoC gene of the soluble methane monooxygenase gene cluster were specific to strain M. Recovery of the cells with a membrane filter enabled us to detect strain M in trichloroethylene-contaminated groundwater. We used the enumeration method to monitor the number of strain M cells in effluent from soil columns supplied with trichloroethylene-contaminated groundwater. The number of strain M cells in the effluent depended on the amount of the strain M inoculated and the number of cells measured by the most probable number-polymerase chain reaction method was correlated with that measured by a culture method. The detection limit for strain M in effluent detected by MPN-PCR method was 4 to 8 x 10(2) cells/ml.

Biodegradation, Environmental↗
PubMed2001

Birth weight and gestation length of Japanese black calves following transfer of embryos produced in vitro with or without co-culture.

Birth weight and gestation length of calves following the transfer of in vitro produced (IVP) embryos with or without co-culture of cumulus cells, were compared to those produced in vivo (IVD). Spermatozoa from one Japanese Black bull were used for both IVP and IVD. IVP embryos were produced using two types of culture method: 1) co-culturing with cumulus cells in TCM 199 supplemented with calf serum (IVP-Co), and 2) non-co-culturing without cumulus cells in CR1aa supplemented with BSA / calf serum (IVP-NON-Co). Both IVP and IVD embryos were transferred non-surgically to Holstein recipients on day 7+/-1 of the estrous cycle. Birth weight and gestation length of half-sib single calves were analyzed. No differences were observed in birth weight and gestation length between IVP-Co and IVP-NON-Co calves (31.0 kg and 31.8 kg, and 291.9 days and 291.0 days, respectively). However, the birth weight of the IVP-Co and IVP-NON-Co calves was significantly higher than that of the IVD calves (P<0.01). Gestation length of the IVP-Co and IVP-NON-Co calves was also significantly longer than that of the IVD calves (P<0.01).

Animals↗
PubMed2001

Horizontal transmission of Toxoplasma gondii in squirrel monkeys (Saimiri sciureus).

The possibility of horizontal transmission of T. gondii was examined in squirrel monkeys. After three monkeys were inoculated perorally with 1.1-2.1 x 10(3) cysts of the T. gondii ME49, the animals were divided into two cages and maintained with one normal monkey for each cage as a cagemate. Two out of the three T. gondii-inoculated monkeys died, and the remaining one monkey was sacrificed in a moribund state one week after infection because of acute toxoplasmosis. Many T. gondii tachyzoites were recovered from broncho-alveolar lavages and were also found histopathologically in the lung, liver, spleen, kidney and lymph nodes and impression smears of tissues from the three T. gondii-inoculated monkeys by Giemsa staining. Anti-T. gondii antibody was examined by immunoblot assay in these animals, and the antibody to T. gondii major surface membrane protein (p30) could be detected after the start of experiment. Furthermore, a specific band of T. gondii NTPase gene was observed by PCR in the liver and lung of infected and cagemate monkeys, and the sequence of the second PCR products obtained from the cagemates, which were clinically normal but gave a positive result in immunoblotting assay, was exactly the same as the sequence of the NTPase gene of T. gondii ME49. These findings suggested that transmission of T. gondii from the infected monkeys to cagemates occurred easily, and since many T. gondii tachyzoites were recovered from the bronchoalveolar lavages of the three T. gondii-inoculated monkeys, we suggest that aerosol infection plays an important role for the enzootic toxoplasmosis in colonies of squirrel monkeys.

Aerosols↗
PubMed2001

Marked uptake of technetium-99m pertechnetate by parathyroid adenoma.

We herewith report an unusual case of primary hyperparathyroidism whose parathyroid adenoma strongly accumulated technetium (Tc)-99m pertechnetate. A 41-year-old woman was referred to our department under the tentative diagnosis of primary hyperparathyroidism. Scintigraphy by thallium-201 chloride showed homogeneous uptake in the whole thyroid, whereas Tc-99m image revealed a strong local accumulation in the middle portion of the right thyroidal lobe. Neck exploration revealed a 12x8x5 mm tumor in the posterolateral region of the right thyroidal lobe, the pathology of which was parathyroid adenoma. In addition, a small nodule (8 mm in diameter) with pathological findings revealing follicular adenoma of the thyroid, was found within the medial portion of the right thyroidal lobe. Both lesions were removed by surgery, and a postoperative Tc-99m scintigraphy no longer demonstrated a significant uptake in the right thyroidal lobe. Since the thyroid adenoma was too small to be detected by any scintigraphic study and located much closer to the median line than the site of the marked accumulation of Tc-99m pertechnetate, it was considered very likely that the parathyroid adenoma concentrated Tc-99m. Search of literature revealed that there have been only thirteen cases of parathyroid tumor reported to date which significantly accumulated Tc-99m pertechnetate. The present patient represents another rare case of parathyroid adenoma showing sueh an unusual scintigraphic image.

Adenoma↗
PubMed2001

Measurement of cerebral hemodynamics with perfusion-weighted MR imaging: comparison with pre- and post-acetazolamide 133Xe-SPECT in occlusive carotid disease.

BACKGROUND AND PURPOSE: We generated regional cerebral blood volume (rCBV) and regional cerebral blood flow (rCBF) studies from dynamic susceptibility contrast-enhanced MR images after an intravenous bolus injection of contrast agent (perfusion-weighted imaging [PWI]) by applying indicator dilution theory. We used a multishot echo-planar imaging (EPI) sequence to obtain adequate arterial input function (AIF). Our purpose was to compare the cerebral hemodynamics measured by PWI with the rCBF values and cerebral perfusion reserve obtained by xenon-133 single-photon emission CT (133Xe-SPECT). METHODS: Eight patients with chronic internal carotid artery occlusion or stenosis were examined. PWI data were acquired using a multishot EPI sequence, and the AIF was determined automatically. Our procedure was based on indicator dilution theory and deconvolution analysis. To eliminate the effect of superficial vessels, the automatic threshold selection method was used. RESULTS: AIF was adequate to generate rCBF and rCBV images. The rCBF and rCBV images by PWI were superior to 133Xe-SPECT scans in spatial resolution, and the rCBF values obtained by PWI correlated well with those obtained by 133Xe-SPECT. The regions with severely decreased perfusion reserve, which were determined by pre- and post-acetazolamide 133Xe-SPECT, showed significantly lower rCBF and higher rCBV by PWI than did regions with normal and moderately decreased perfusion reserve. CONCLUSION: The rCBF and rCBV images generated by our procedure using PWI data appear to provide important clinical information for evaluating the degree of cerebral perfusion reserve impairment in patients with chronic ischemia.

Acetazolamide↗
PubMed2001

[T-cell prolymphocytic leukemia complicated by diffuse large B-cell lymphoma of the stomach].

We describe a case of T-cell prolymphocytic leukemia (T-PLL) in a 76-year-old man, who developed diffuse large B-cell lymphoma (DLBL) of the stomach, a previously unreported occurrence. The patient was referred to our hospital because of marked leukocytosis (40,000/microliter) without clinical symptoms. He was diagnosed as having T-PLL on the basis of the characteristic cell morphology and immunophenotype (CD2+, CD3+, CD4+, CD5+, CD7+, CD8-, CD25-, TCR alpha/beta+), but cytogenetic analysis showed no abnormalities. Fifteen months later, he developed a gastric tumor. Biopsy of the tumor revealed DLBL without features of MALT lymphoma; Helicobacter pylori was not detected. Chemotherapy eradicated the tumor, whereas the T-PLL was resistant to the therapy. The disease showed an indolent course for about 2 years thereafter. Immunological derangement due to T-PLL might have potentiated the development of DLBL in this case.

Aged↗