Search PubMed⌕ Search

Biomedical subjects

Y Fukuda

Publications and source records attributed to Y Fukuda.

At least 505 records · Page 28Linked to original sources
PubMed1994

Synchronous appearance of fibronectin, integrin alpha 5 beta 1, vinculin and actin in epithelial cells and fibroblasts during rat tracheal wound healing.

The distribution of integrin alpha 5 beta 1 (alpha 5 beta 1) and associated components during wound healing was investigated in the rat trachea following mechanical injury. Under anesthesia, the ventral surface of the trachea was scratched, and tissue specimens were obtained from 6 h to 3 weeks after injury and studied using light and electron microscopy and immunohistochemistry. alpha 5 beta 1, vinculin and actin in regenerating epithelial cells and extracellular fibronectin appear virtually simultaneously after injury (from 12 h to 7 days) as do alpha 5 beta 1, vinculin and alpha-smooth muscle actin in fibroblasts and cellular fibronectin in granulation tissue (from 3 to 10 days). Immunoelectron microscopy 2 days after injury showed that alpha 5 beta 1 and vinculin were localized on the basal and lateral surfaces of regenerating epithelial cells and fibroblast surfaces, and fibronectin was localized just under the regenerating epithelial cells, around collagen fibrils and sporadically around fibroblasts. Bromodeoxyuridine labeling showed that the appearance of these components was associated with the period of cell proliferation. The appearances of fibronectin, alpha 5 beta 1, vinculin and actin in regenerating epithelial cells and fibroblasts during tracheal wound healing are well coordinated. During the initial cell migration phase, plasma fibronectin may stimulate cell migration before cellular fibronectin is produced in situ, and regenerating epithelial cells appear to begin to migrate into the wound before cell proliferation starts.

Actins↗
PubMed1994

Myelination of regenerated optic fibers in peripheral nerve graft of adult cats.

Retinal ganglion cells of adult cats have the potential to regenerate their axons into autografted peripheral nerve. Two months after transplantation of the sciatic nerve to the axotomized optic stump, regenerated axons were labeled anterogradely with biocytin, and myelin formation by Schwann cells was examined electron microscopically. Both myelinated and unmyelinated fibers were labeled with biocytin. Among 511 axons labeled in three grafts, 96 fibers (18.8%) were myelinated and 415 (81.2%) were unmyelinated. Mean diameter with SD of myelinated fibers was 1.28 +/- 0.39 micron (range 0.71-2.47) and that of unmyelinated fibers was 0.76 +/- 0.38 micron (range 0.18-2.46). The ratio of inner to outer diameters of the myelin sheath (g value) was 0.82, which is close to the value (0.8) for the optic fibers of intact adult cats.

Animals↗
PubMed1994

A case report suggesting a common pathogenesis for IgA nephropathy and Henoch-Schönlein purpura.

A 7-year-old boy who had been followed for asymptomatic haematuria and elevated serum IgA levels developed Henoch-Schönlein purpura (HSP) after a streptococcal infection of the tonsils. Findings on renal biopsy were compatible with mild IgA nephropathy (IgAN); tonsillectomy was also performed as he had chronic tonsillitis. This case suggests that there is a common pathogenesis for IgAN and HSP, at least in some patients.

Child↗
PubMed1994

The significance of bile secretion after the transplantation of long-preserved livers in the rat.

Although one of the simplest indicators for predicting liver viability is bile secretion, it has never been proven whether it could be a good index for the viability of grafts in liver transplantation after cold ischemia. The present study, conducted on male Wistar rats, was undertaken to determine whether bile secretion reflects the viability of livers which have been preserved long-term. Livers were stored for up to 24 h in Euro-Collins (EC) or University of Wisconsin (UW) solution at 4 degrees C, and transplanted orthotopically. The correlation between 1-week survival, bile flow, and the tissue adenosine triphosphate (ATP) level 4 h after transplantation was then investigated for each subgroup. The survival rates of the animals in the UW subgroups were much higher than those in the EC subgroups. In the rats transplanted with livers preserved for 6 h in EC solution (EC-6), in which 100% survival was observed, both bile flow and ATP recovered sufficiently. Conversely, in the EC-12 group, in which only 10% survival was seen, restoration of bile flow, in ml/h per kg body weight, and ATP resynthesis, in mumol/g wet weight, were severely suppressed, with levels of 1.35 +/- 1.05 and 0.77 +/- 0.34, respectively. Moreover, in the EC-18 group, with 0% survival, neither bile flow nor ATP recovered. In the rats transplanted with livers preserved for 18 h in UW solution (UW-18), bile flow and ATP, being 1.03 +/- 0.56 and 1.12 +/- 0.59, respectively, were much higher than those in the EC-18 group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1994

Metastatic potential of human colorectal carcinoma SW1222 cells transfected with cDNA encoding carcinoembryonic antigen.

In order to examine a role of carcinoembryonic antigen (CEA) in metastasis, cDNA encoding CEA was introduced into a clone of human colorectal carcinoma SW1222 cells. Western blot analysis revealed that all transfectants express CEA of 180 kDa while the parent clone does not. In the transfectants, the level of CEA expression in clone 3 was higher than that of clone 1. Clone 3 formed aggregates rapidly after suspended by trypsinization while clone 1 did not. In experimental metastasis assay where tumor cells were injected intrasplenically, clone 3 exhibited a higher liver-metastatic activity than clone 1. Fab fragment of anti-CEA antibody significantly inhibited both the cell aggregation and the liver metastases caused by clone 3. These findings suggested that CEA expressed on the cell surface may play an important role in hepatic metastasis from colorectal carcinoma, possibly through its cell adhesion activity.

Animals↗
PubMed1994

A clinico-epidemiological analysis of Helicobacter pylori (H. pylori) by Southern blotting with A urease gene probe.

Helicobacter pylori (H. pylori) is a gram-negative bacillus thought to be involved in such diseases of the upper gastrointestinal tract as gastritis, peptic ulcers, and gastric cancer. Urease is regarded as the factor responsible for the pathogenic nature of this bacterium. Therefore, in our examination of the genetic polymorphism of H. pylori, by means of Southern blotting, we used the urease gene as a probe. The Southern blot patterns of H. pylori isolated from different patients differed greatly, the inter-individual variation being so marked that it allowed approximate distinction between individual patients. The Southern blot patterns of individual strains of H. pylori did not change, even when they were stored and passed from generation to generation in our laboratory. These results suggest that DNA fingerprints with a urease gene probe will be useful in epidemiologically tracing H. pylori infection. Almost all strains of H. pylori isolated from different sites in the stomach of a patient on different occasions showed the same pattern, allowing us to confirm that only one strain of H. pylori was responsible for H. pylori infection in individual patients.

Blotting, Southern↗
PubMed1994

Expression and localization of gamma-aminobutyric acid A (GABAA) receptor alpha 1 subunit and L-glutamate decarboxylase (GAD) mRNAs in rat retina: an analysis by in situ hybridization.

The localization of the mRNAs encoding gamma-aminobutyric acidA receptor alpha 1 subunit (GABAA alpha 1) and L-glutamate decarboxylase (GAD) was elucidated in the rat retina by in situ hybridization. Soma diameter analysis of signal positive cells in the ganglion cell layer demonstrated that a subpopulation including alpha-cells of retinal ganglion cells expressed GABAA alpha 1 mRNA and a subpopulation of ganglion cells smaller than alpha-cells expressed GAD mRNA.

Animals↗
PubMed1994

Fc epsilon RI-stimulated Ca(2+)-dependent secretion from rat basophilic leukemia (RBL-2H3) cells permeabilized with Staphylococcal alpha-toxin: Fc epsilon RI-operated signals are not mimicked by the actions of GTP gamma S.

1. RBL-2H3 cells permeabilized with alpha-toxin responded to dinitrophenol (30-40 mol/mol)-conjugated human serum albumin, as antigen, to secrete [14C]serotonin in the micromolar range of free Ca2+. 2. Calcium ion alone did not cause substantial secretion. 3. Guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) (100 microM) in combination with Ca2+ produced only negligible [14C]serotonin secretion. 4. GTP gamma S, in the presence of cytochalasin D, caused optimal secretion of [14C]serotonin in a Ca(2+)-dependent manner.

Adenine↗
PubMed1994

Effects of intrahepatic arterial and intraportal administration of FK 506 on liver allograft survival in rats.

Rejection is still the limiting factor for successful organ transplantation, and overdosage of immunosuppressive drugs often results in severe viral infection, side-effects and toxicity. Thus, more specific immunosuppression to lessen these side-effects is highly desirable. In this study, we compared the effects of FK 506 administered by different routes (hepatic artery, portal vein and systemic circulation) on the inhibition of rejection. FK 506 was given to recipient LEW rats with PVG liver grafts via the penile vein (systemic administration), portal vein or hepatic artery (local administration) for 3 or 7 successive days after liver transplantation. In control LEW rats without immunosuppression, the PVG liver allografts were rejected between 9 and 21 days after transplantation. Intravenous administration of FK 506 for 3 days (0.32 and 1.28 mg/kg daily) only had a marginal effect on prolonging liver allograft survival (21.1 +/- 12.5 and 32.0 +/- 24.0 days, respectively; control 14.1 +/- 4.1 days). However, systemic administration of FK 506 (0.08-1.28 mg/kg daily) for 7 days suppressed liver allograft rejection markedly (42.3 +/- 5.9 to 80.5 +/- 53.4 days; control 14.1 +/- 4.1 days), and 50% of the recipient rats survived for at least 60 days after liver transplantation. Moreover, when a low dose of FK 506 (0.32 mg/kg) was infused into the hepatic artery or portal vein of the transplanted liver for 3 days only, liver allograft survival times were prolonged markedly, and 54% of rats with grafts survived for at least 60 days. This effect was almost equal to that after 7 days systemic treatment with FK 506. In conclusion, 7 days' treatment with FK 506 administered systemically was an effective regimen for the suppression of liver allograft rejection in rats. Furthermore, local immunosuppression with low-dose, short-term (3 days) FK 506 treatment administered via the hepatic artery or portal vein of the transplanted liver dramatically improved allograft salvage.

Animals↗
PubMed1994

Successful 48-h liver preservation by controlling nutritional status of donor and recipient.

The nutritional status of the donor has been shown to affect the outcome of liver transplantation in the rat. It has been proposed that this may be due to inhibition of Kupffer cell induced injury to the reperfused organ, which leads to an inflammatory type response. In this study we investigated how altering the nutritional status of the recipient affects the outcome of liver transplantation after preservation of the liver for 44 or 48 h in the University of Wisconsin (UW) solution. The nutritional status of the rats was altered by either fasting or by feeding an essential fatty acid free diet (EFAD) for 2 months. This type of diet has been shown to reduce significantly the inflammatory response in rats. Survival after 44-h preservation of livers from fed donors (fed a standard laboratory diet) transplanted to fed recipients was 29% (2/7) but increased to 80% (4/5) when the recipient was fed the EFAD diet. After 48-h preservation, there were no survivors under either of these two dietary combinations. However, survival was 100% after 48-h preservation if the donor had been fasted for 4 days and the recipient was fed the EFAD. These results showed that the nutritional status of the donor and recipient are important factors in the outcome of liver transplantation. How nutritional factors affect liver preservation and transplantation are not clear but may be related to the inflammatory response regulated by Kupffer cells and circulating neutrophils in the liver, both of which are influenced by the diet of the animal.

Adenosine↗
PubMed1994

In vivo near-infrared monitoring of nitric oxide production and tissue oxygen sufficiency in rat liver allografts during the acute rejection reaction.

We established a new technique of in vivo near-infrared (NIR) spectroscopy that can estimate both nitric oxide (NO) production and tissue oxygen sufficiency in living organs during the alloimmune response. The present study was aimed at evaluating the potential of this technique for monitoring the rejection response utilizing the rat model of orthotopic liver transplantation without arterialization. The relative changes of nitrosyl-hemoglobin, oxyhemoglobin and oxidized-cytochrome oxidase in the graft livers were quantified by use of this method. Nitrosyl-hemoglobin in the allogenic grafts was elevated at the onset of the rejection response and was suppressed when the rejection reaction was treated by the administration of 15-deoxyspergualin. Oxy-hemoglobin and oxidized-cytochrome oxidase were decreased in accordance with parenchymal disorder determined histologically. These results demonstrated that the new technique of in vivo NIR spectroscopy can assess simultaneously both the immune response and graft function after liver transplantation.

Animals↗
PubMed1994

Inhibition of IL-2 synthesis by donor-specific suppressor T cells in a renal transplant recipient.

A study was conducted to elucidate the mechanism of donor-specific Mixed Lymphocyte Reaction (MLR and Cell Mediated Lymphotoxicity (CML) unresponsiveness in a renal transplant recipient with a long-term well-functioning kidney. The peripheral blood lymphocytes (PBL) of the recipient, who had not shown rejection since his transplantation 5 years previously, and those of his mother (donor), his father and two healthy third parties were examined. MLR, CML, semimicro MLR in a double chamber, interleukin-2 (IL-2) synthesis assay and limiting dilution assay were performed. This recipient showed donor-specific MLR and CML unresponsiveness. IL-2 assay showed that the PBL of the recipient produced less IL-2 against the donor than against the father and the third parties. The addition of exogenous recombinant IL-2 (rIL-2; Takeda Co.) to the priming MLR caused a recovery of CML against the donor. A limiting dilution assay indicated that cytotoxic T cell precursor (CTLp) frequencies against the donor and father did not differ. The suppressor assay in a double chamber indicated that the PBL of the recipient stimulated by the donor PBL had a non-specific suppressive effect on MLR, CML and IL-2 synthesis of the PBL across the Major Histocompatibility Complex (MHC) barrier. This suppressive effect was abolished by OKT3 or OKT8 monoclonal antibody and complement. Thus, the recipient had donor-specific suppressor T cells that produced a humoral non-specific suppressive factor only when stimulated by the donor PBL, and this factor suppressed MLR and CML by inhibiting IL-2 synthesis of the PBL.

Antibodies, Monoclonal↗
PubMed1994

Fibronectin and tenascin in rat tracheal wound healing and their relation to cell proliferation.

To investigate the relationship between cell proliferation and distribution of fibronectin and tenascin during wound healing, light and electron microscopy and immunohistochemistry for fibronectin, tenascin, and 5-bromodeoxyuridine (BrdU) were performed following mechanical injury of rat trachea. Tenascin staining appeared 18 h after curettage, when the percentage of BrdU-positive nuclei was maximal in the epithelium. Once tenascin appeared, the labeling index of BrdU-positive epithelial nuclei decreased rapidly. Distribution of tenascin was restricted to granulation tissue in curetted areas which were covered with regenerating epithelium, while fibronectin stained diffusely in both curetted and non-curetted areas. Analysis of the relative intensity of fibronectin and tenascin staining showed that decreases of fibronectin staining were followed by increasing tenascin staining. It is proposed that fibronectin and tenascin may contribute differently to tissue repair in the trachea by interfering with cell proliferation of epithelial cells and fibroblasts.

Animals↗
PubMed1994

Distribution and elimination of sulphadimethoxine and its metabolites in treated chicken.

Sulphadimethoxine (SDM), and its metabolites, N4-acetyl SDM, N1-(2-methyl-6-hydroxy-4-pyrimidinyl) sulphanilamide (6-OH-SDM), N1-(6-methyl-2-hydroxy-4-pyrimidinyl) sulphanilamide (2-OH-SDM), N1-(2,6-dihydroxy-4-pyrimidinyl) sulphanilamide (2,6-diOH-SDM) and SDM N1-glucuronide in chicken tissues were extracted, partially purified by Bond Elute SCX cartridges, and assayed and identified by HPLC/LC-MS after administration of SDM to chickens. During the administration and 24 h after withdrawal, SDM and 6-OH-SDM were observed in almost all tissues and excreta. N4-Acetyl SDM and 2,6-diOH-SDM were observed in some tissues, but 2-OH-SDM and SDM N1-glucuronide were observed in a few limited tissues. Twenty four hours after withdrawal, SDM and its metabolites, except 6-OH-SDM, decreased. SDM and its metabolites were eliminated from all tissues within 48 h of withdrawal.

Animals↗
PubMed1994

Proinflammatory cytokines in nasal secretions of allergic subjects after antigen challenge.

To study the role of cytokines in allergic late-phase reactions (LPR), we measured cytokines (interleukins [IL]-1 beta, IL-2, IL-4, IL-5, IL-6, and granulocyte-macrophage colony-stimulating factor [GM-CSF]) in nasal secretions (NS) of eight allergic subjects following antigen or saline provocation. NS were collected hourly for 10 h after challenge by a newly developed matrix method. All subjects recorded hourly symptom scores. Cytokines were measured using specific enzyme-linked immunosorbent assays (ELISA). Compared with prechallenge values, significant levels of IL-1 beta were detected in all subjects during the immediate reaction (peak, 51.0 +/- 22.4 pg/ml) and LPR (peak, 78.5 +/- 22.6 pg/ml) after antigen challenges (p < 0.01) but not saline challenges. In contrast, GM-CSF and IL-6 showed a delayed rise (peak, 26.4 +/- 1.3 pg/ml and 33.8 +/- 10.0 pg/ml, respectively) at hour 4 in the antigen-challenge period (p < 0.01 versus saline). NS from 4 donors also showed detectable IL-5 (7.6 to 155 pg/ml) during the immediate reaction and LPR after allergen challenges (versus saline, p < 0.01). The levels of cytokine correlated (p < 0.05) with corresponding total symptom scores during the immediate reaction (IL-1 beta) and LPR (IL-1 beta, GM-CSF, and IL-6). IL-2 and IL-4 were not detected in any sample. Thus, IL-1 beta, IL-5, IL-6, and GM-CSF are present in the LPR of allergic rhinitis, and their correlation with clinical responses may suggest their role in allergic inflammation.

Enzyme-Linked Immunosorbent Assay↗
PubMed1994

Regulation of oxygen delivery and consumption in anesthetized rats during acute hypoxia.

Physiological roles of ventilatory responses to acute hypoxia in the regulation of O2 transport and consumption were evaluated quantitatively in halothane anesthetized and spontaneously breathing rats with or without peripheral chemoreceptor afferents. Ventilation (VE), blood gas values, cardiac output (Q), and whole-body O2 consumption (VO2) were measured at various levels of inspired O2 concentration (FIO2) before and after denervation of carotid chemoreceptor afferents. In the carotid sinus nerve (CSN)-intact rat, the reduction in FIO2 from > 0.27 (hyperoxia) to about 0.10 (mild-moderate hypoxia) elicited an augmentation of VE which was accompanied by a well maintained total amount of O2 delivered to tissue (Q x O2 content of arterial blood, DO2) and VO2. The increase in VE was, however, turned off and the VE value did not differ from that in hyperoxia at FIO2 lower than 0.10 (moderate-severe hypoxia) (hypoxic ventilatory depression, HVD). Significant decreases in Q, DO2, and VO2 were also seen at FIO2 < 0.10. After CSN section, VE, Q, DO2, and VO2 values decreased progressively with the reduction in FIO2 from hyperoxia to mild hypoxia (FIO2 = 0.20-0.15). These findings indicate that the normal DO2 and VO2 are preserved in the presence of carotid chemoreceptor afferents in the FIO2 range > 0.10 and that HVD is accompanied by the decrease in VO2. Summarizing all results, VO2 decreased linearly with the reduction in PaO2 lower than about 60 mmHg or DO2 lower than 4 ml/min/100 g bw (critical PaO2 or DO2 for metabolic suppression), above which VO2 remained unchanged. The decrease in VO2 in lower PaO2 or DO2 levels (hypoxic hypometabolism) ensues perhaps from "adaptive" mechanisms reducing O2 demand when adequate O2 supply to tissue is limited.

Animals↗