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Biomedical subjects

Y Fukui

Publications and source records attributed to Y Fukui.

At least 181 records · Page 10Linked to original sources
PubMed1997

Induction of Fos-like immunoreactivity in the lower brainstem and the spinal cord of the rat by intraperitoneal administration of an endogenous satiety substance, 2-buten-4-olide.

Induction of Fos in neurons by intraperitoneal injection of 2-buten-4-olide (2-B40), an endogenous satiety substance, was studied immunohistochemically in the brainstem and spinal cord of the rat. Rats injected intraperitoneally with 2-B40 (100 mg/kg) were allowed to survive for 2 h before perfusion. Fos-like immunoreactivity was observed in neurons of the intermediolateral nucleus, ventral reticular formation, lateral reticular nucleus, nucleus of the solitary tract, locus coeruleus, lateral parabrachial nucleus and dorsal raphe nucleus, as well as in tyrosine hydroxylase-immunoreactive neurons of the cell groups A1, A2, A5, A6, A7, C1, C2 and C3.

4-Butyrolactone↗
PubMed1997

A target of phosphatidylinositol 3,4,5-trisphosphate with a zinc finger motif similar to that of the ADP-ribosylation-factor GTPase-activating protein and two pleckstrin homology domains.

We have purified a protein that binds phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P3] using beads bearing a PtdIns(3,4,5)P3 analogue. This protein, with a molecular mass of 43 kDa, was termed PtdIns(3,4,5)P3-binding protein. The partial amino acid sequences were determined and a full-length cDNA encoding the protein was isolated from bovine brain cDNA library. The clone harbored an open reading frame of 373 amino acids which contained one zinc finger motif similar to that of ADP-ribosylation-factor GTPase-activating protein and two pleckstrin homology domains. The entire sequence was 83% similar to centaurin alpha, another PtdIns(3,4,5)P3-binding protein. The protein bound PtdIns(3,4,5)P3 with a higher affinity than it did inositol 1,3,4,5-tetrakisphosphate, phosphatidylinositol 4,5-bisphosphate, phosphatidylinositol 3,4-bisphosphate, and phosphatidylinositol 3-phosphate suggesting that the binding to PtdIns(3,4,5)P3 was specific. The binding activity was weaker in the mutants with a point mutation in the conserved sequences in each pleckstrin homology domain. Introduction of both mutations abolished the activity. These results suggest that this new binding protein binds PtdIns(3,4,5)P3 through two pleckstrin domains present in the molecule.

ADP-Ribosylation Factors↗
PubMed1997

Amoeboid movement anchored by eupodia, new actin-rich knobby feet in Dictyostelium.

To date, protrusion of pseudopodia has been considered to be primarily responsible for translocation of free-living amoebae and leukocytes of higher organisms. Although there is little question that the pseudopodium plays an important role, little attention has been given to the cortical structures that are responsible for cell-substratum anchorage in amoeboid movement. Here, we report on a new knobby foot-like structure in amoebae of a cellullar slime mold, Dictyostelium discoideum. These feet, each about 1 micron in diameter, appear transiently in multiple units at the base of certain pseudopodia where the amoeba contacts a partially deformable substrate. The feet were discovered, and their spatial and temporal behavior relative to pseudopodial anchorage and invasive locomotion were observed, by examining Dictyostelium amoebae using a DIC video microscope providing an 0.3 micron depth of field. Key evidence for the anchoring role of the knobby feet was obtained by investigating amoebae, flattened in a specially devised observation chamber, and attracted by chemotaxis towards 3',5' cyclic-adenosine monophosphate (cAMP). The cAMP was released by highly localized, pulsed UV-microbeam irradiation of caged cAMP. We show by indirect immunofluorescence that the knobby feet contain a high concentration of filamentous (F-) actin, myoB (a member of Dictyostelium myosin-I family), and alpha-actinin (an actin-binding protein). Interestingly, myoB exhibits a circular disposition around each foot. Neither myosin-II (conventional myosin) nor the 269 kD protein, which has been recently identified as a talin homologue of Dictyostelium [Kreitmeier et al., 1995: J. Cell Biol. 129:179-188], are concentrated at the feet. We propose that the knobby feet provide anchorage to the substratum needed by lamellipodia to exert projectile forces for invading narrow spaces or otherwise for a flattened amoeba to secure itself to the deformable substratum. Some forms of adhesion plaques in higher organisms such as "podosomes" or "invadopodia" may perform functions similar to the knobby feet, but appear to differ in life time, cytoskeletal organization and composition. We have named the knobby foot "eupodium."

Animals↗
PubMed1997

Phosphatidylinositol-3 kinase is involved in ruffled border formation in osteoclasts.

Phosphatidylinositol (PI)-3 kinase has been implicated in several aspects of intracellular membrane trafficking, although the detailed mechanism is yet to be established. We previously reported that wortmannin (WT), a selective inhibitor of PI-3 kinase, inhibited the bone-resorbing activity of osteoclasts (Nakamura et al., 1995, FEBS Lett., 361:79-84). In this study, we examined how PI-3 kinase was involved in membrane trafficking in osteoclasts which are primary bone-resorbing cells. Osteoclasts exhibit a highly polarized cytoplasmic organization, the ruffled border. Ruffled borders are formed by numerous deep membrane invaginations, on which vacuolar H(+)-ATPase (V-ATPase) is localized in a high density. Immunoelectron microscopic analyses revealed that PI-3 kinase was specifically present along ruffled border membranes and the limiting membranes of associated intracellular vacuoles in rat authentic osteoclasts. WT and LY294002, another inhibitor of PI-3 kinase, caused the accumulation of numerous acidic vacuoles which were stained with acridine orange in murine osteoclast-like multinucleated cells formed in vitro. An electron microscopic examination showed that these vacuoles contained V-ATPase along their limiting membranes and appeared to be derived from the Golgi apparatus as ruffled border precursors. A time course study revealed that WT-induced vacuoles began to accumulate in the region close to the apical membrane and were finally distributed throughout the cytoplasm. Removal of WT from the culture medium resulted in the disappearance of vacuoles in the cytoplasm, leading to the formation of ruffled borders. During the culture period, some vacuoles were observed to fuse with the ruffled border membrane. A pit formation assay on dentine slices also showed that the pit-forming activity of osteoclast-like cells was recovered by the removal of WT from the assay. These results suggest that PI-3 kinase plays an important role in ruffled border formation in osteoclasts, probably in the fusion of membrane vacuoles with the plasma membrane.

Androstadienes↗
PubMed1997

Identification of an HLA-DQ6-derived peptide recognized by mouse MHC class I H-2Db-restricted CD8+ T cells in HLA-DQ6 transgenic mice.

CD8+ T cells from C57BL/6(B6) mice show cytotoxicity to B cell blasts prepared from syngeneic transgenic mice expressing HLA-DQ6 molecules in a mouse MHC class I H-2Db restricted manner. Although these results suggest that CD8+ T cells recognize peptides derived from DQ6 molecule bound to H-2Db on target cells, no direct evidence so far has been obtained. To clarify this, we synthesized 23 peptides corresponding to DQ6 alpha or beta chain and carrying the motifs of Db-binding peptides, and examined their capacity to induce cytotoxicity in the CD8+ T cell line. We show here that DQA1-2, one of these peptides, induced cytotoxicity of the CD8+ T cells when this peptide was pulsed to H-2Db expressing target cells, as efficiently as HLA-DQ6 expressing target cells did. Thus, our results suggest that DQA1-2 can be naturally processed from DQ6 molecules and recognized by the CD8+ T cells in the context of H-2Db molecules. These results suggest that allogeneic HLA class II molecules are involved in the rejection not only as the ligand for T cell receptor of alloreactive CD4+ T cells but also as self-peptides bound to HLA class I molecules recognized by CD8+ T cells.

Animals↗
PubMed1997

The minor outer capsid protein P2 of rice gall dwarf virus has a primary structure conserved with, yet is chemically dissimilar to, rice dwarf virus P2, a protein associated with virus infectivity.

The nucleotide sequence of the genome segment 2 (S2) of rice gall dwarf virus (RGDV), a phytoreovirus, when compared with the amino acid sequence of a component protein of the virus, showed that S2 potentially encoded a 127K minor outer capsid protein. This 127K protein designated as P2 and the 127K minor outer capsid protein (also termed P2) of rice dwarf virus (RDV) are similar in size, located in the outer capsid, and have well-conserved predicted polypeptide sequences, suggesting similar functions. Infectivity to insect vector cell monolayers of RGDV was maintained and the P2 protein was retained irrespective of carbon tetrachloride (CCl4) treatment. This is in contrast to the infectivity of RDV which is removed along with P2 protein following CCl4 treatment. RGDV with P2 was acquired by vector insects and transmitted to host plants, although RDV lacking P2 could not be transmitted to plants as previously published. These results imply that RDV and RGDV require P2 proteins for virus infectivity to vector insects.

Amino Acid Sequence↗
PubMed1997

Hyaluronic acid of wound fluid in adult and fetal rabbits.

Fetal wound healing proceeds without fibrosis or scar formation in contrast to adult wound healing. The mechanisms responsible for this remarkable process are mediated in part through a fetal wound extracellular matrix rich in hyaluronic acid (HA). Polyvinylalcohol sponge (PVA) wound implants were placed pervertebrally at 24 days' gestation in fetal (N = 118) rabbits and in adult (N = 44) rabbits, and then harvested at 1, 2, 3, 4, 5, and 7 days postwounding. To analyze the fetal and adult wound matrix, the HA concentration of wound fluid within the PVA sponge was quantitated using a newly developed assay. A significantly increased (P < .05) HA deposition on days 1 through 7 in the fetal wounds was found compared with the adult wound. These observations may suggest an important physiologic role in fetal wound healing by providing a more fluid and malleable matrix. These results, coupled with earlier findings of the lack of an acute inflammatory response in the fetus, further support the hypothesis that fetal response to injury is significantly different from adult response in this prescience of an implanted PVA sponge.

Aging↗
PubMed1997

Experience in tracheobronchial reconstruction with a costal cartilage graft for congenital tracheal stenosis.

Although successful surgical management of congenital tracheal stenosis has been reported, it is still controversial as to the best operative procedure. Eleven infants with congenital tracheal stenosis were evaluated to confirm the efficacy of tracheobronchial reconstruction with costal cartilage graft. Symptoms ranged from recurrent respiratory infection to severe respiratory failure. All infants had other congenital anomalies in addition to tracheal stenosis. Notably, five infants had pulmonary artery sling and four infants had patent ductus arteriosus. Definitive diagnosis was made by bronchoscopy, results of which showed complete tracheal rings in all patients with severely compromised tracheobronchial lumens. Five infants had elongated stenosis involving nearly the whole length of the trachea, and five infants had segmental stenosis involving nearly one half the length of the trachea. One infant had bilateral stenosis of the main bronchi. Early experience included two deaths from problems related to the repair. The involvement of the carina and the distal portion of the trachea was associated with increased complications and a higher mortality rate. Currently, our preferred technique facilitated by extracorporeal membrane oxygenation (ECMO) includes carinal reconstruction with a thin-wall intraluminal stent. Bronchoscopy is essential for accurate intraoperative incision of the trachea, post-operative airway management for several weeks, and removal of the intraluminal stent.

Bronchi↗
PubMed1997

Nitric oxide inhalation therapy for an infant with persistent pulmonary hypertension caused by misalignment of pulmonary veins with alveolar capillary dysplasia.

Misalignment of pulmonary veins with alveolar capillary dysplasia (MPV) has been reported to be a rare cause of persistent pulmonary hypertension of the newborn (PPHN) and to be fatal despite extracorporeal membrane oxygenation (ECMO). A full-term female neonate with PPHN was brought to the hospital for ECMO therapy at 2 days of age. On the 14th day of life, she was extubated early after the second run of ECMO, and underwent nitric oxide (NO) inhalation therapy in the incubator. She died of catheter-related sepsis on the 61st day of life. After autopsy findings revealed MPV, the longest survival with this disease was documented. NO inhalation therapy in the incubator may provide time for lung transplantation.

Administration, Inhalation↗
PubMed1997

Factors influencing the outcome of liver transplantation for biliary atresia.

BACKGROUND/PURPOSE: This study examined the factors present before liver transplantation (LTx) influencing the outcome in 14 patients who had biliary atresia (BA) who underwent LTx. RESULTS: Nine patients survived (Group A), whereas five died primarily of infection (Group B). Rate of the attempted multiple hepatic portoenterostomy (HPE) and existence of intestinal stoma was significantly higher in Group B than in Group A. Pre-LTx parameters showed significant difference between the two groups as follows: total bilirubin, 15.9 +/- 7.9 versus 29.1 +/- 14.5 mg/dL (P = .0446); gamma-glutamyl transpeptidase, 170.0 +/- 97.6 versus 65.2 +/- 38.8 IU/L (P = .0425); the body weight deviation score, 0.17 +/- 0.88 SD versus -1.46 +/- 0.30 SD (P = .0029); total cholesterol, 129.4 +/- 33.5 versus 52.2 +/- 20.4 mg/dL (P = .0008) in Group A versus Group B. Total cholesterol level and body weight for age remained within normal range until the advanced stage and rapidly decreased according to deterioration of the general condition before LTx. CONCLUSIONS: From these results, avoidance of multiple HPE and closure of stoma before LTx may be preferable. LTx should be performed before failure to thrive or hypocholesterolemia develops.

Analysis of Variance↗
PubMed1997

The restraint stress-induced reduction in lymphocyte cell number in lymphoid organs correlates with the suppression of in vivo antibody production.

In this study, we examined the effects of restraint stress on some immune parameters such as the in vivo antibody levels, cytokine production, and lymphocyte cell number in the spleen or mesenteric lymph node (MLN). BALB/c mice were thus injected intraperitoneally 2-times with OVA absorbed into alum on days 0 and 21. Before the first injection, the animals were either restrained for 12 h (stress group) or returned to their home cage (control group). Exposure to stress resulted in a reduction in the serum levels of anti-OVA IgE, IgG1, and IgG2a. In addition, stress also caused a decrease in the IL-4 and IFN-gamma levels in the spleen or mesenteric lymph node cell culture supernatants. Furthermore, exposure to stress resulted in a decrease in the splenic and mesenteric lymphocyte cell number when examined immediately after the cessation of stress. This decrease persisted for at least 12 h after the termination of stress and thereafter disappeared 24 h after stress. The stress-induced reductions in antibody and cytokine production occurred only when antigen was given either immediately or 6 h after stress, but not when antigen was given 24 h post stress. These results thus suggest that the restraint stress-induced change in lymphocyte cell number in the spleen or MLN closely correlates with the altered antibody and cytokine levels.

Animals↗
PubMed1997

The presence of h2-calponin in human keratinocyte.

Calponin (h1 isoform) was characterized as a smooth muscle specific, actin-, tropomyosin-, calmodulin-binding protein and described as a factor which inhibits contraction. H2-calponin, encoded by a different gene from h1-calponin, was identified from the smooth muscles of mouse and pig. However, non-muscle calponin analogues have recently been reported in rat and pig brains. Here we show the presence of calponin expressed in human skin tissue and in cultured human keratinocytes using polyclonal antibodies to bovine aortic smooth muscle calponin. Western blot analysis demonstrated that calponin with a molecular weight around 36,000 existed in extracts of keratinocytes. Immunofluorescence microscopy displayed the localization of calponin in the cytoplasm of the basal cells in situ, and along the cell-to-cell borders in cultured human keratinocytes maintained in standard calcium medium. Furthermore, according to RT-PCR analysis using human h1- and h2-calponin-specific primers, calponin expressed by cultured human keratinocytes was identified as the h2 isoform. We demonstrated the presence of h2-calponin in human keratinocytes, and it might play a role in the structural organization of actin cytoskeleton at the cytoplasmic region of cell-to-cell junctions of keratinocytes.

Actins↗
PubMed1997

Positive and negative CD4+ thymocyte selection by a single MHC class II/peptide ligand affected by its expression level in the thymus.

The central event in thymic selection of T cells bearing alpha beta TCRs is their interaction with self-peptides bound to self-MHC molecules. With the use of transgenic mouse lines expressing a single peptide/MHC class II complex, we show that CD4+ T cells with the preferential usage of particular TCR V(alpha)s and V(beta)s were selected to mature on this complex in lines with the lower expression, whereas such CD4+ T cells were eliminated in the thymus in a line with the relatively high expression. When a low expressing line was crossed with a high expressing line, the frequency of CD4+ T cells selected by this complex markedly decreased. Thus, these results suggest that a single peptide/MHC class II complex, being affected by its cell surface density in the thymus, can serve as both positively and negatively selecting ligand in vivo.

Amino Acid Sequence↗
PubMed1997

Epidermal growth factor inhibits morphogenesis of the embryonic quail uropygial gland cultured in vitro.

Formation of the uropygial papilla and glandular lumena was inhibited when the uropygial rudiment of a day 8 1/3 quail embryo was cultured for 2 days in a chemically defined medium in the presence of 50 ng/mL of epidermal growth factor (EGF). The epithelium of EGF-treated explants remained at the placode stage, or underwent minor invagination into the mesenchyme and became stratified like that of a 12- or 13-day-old embryo. EGF promoted cellular proliferation in the uropygial epithelium and the epidermis adjacent to the gland and it shortened the lag phase of proliferation and markedly stimulated epithelial DNA synthesis, detected immunocytochemically by labeling explants with 5-bromodeoxyuridine (BrdU). The maximal labeling index in EGF-treated uropygial epithelium was 55% higher than in the control. Electron microscopic observation revealed that the basal lamina had become irregular in the EGF-treated explants and that epithelial cytoplasmic processes penetrated through the basal lamina toward the mesenchyme. These same phenomena are observed in vivo when the glandular buds are formed during day 12-13. Some precocious changes occurred in the uropygial epithelium when the rudiment was cultured in the presence of EGF.

Animals↗
PubMed1997

A competitive enzyme immunoassay for follicle-stimulating hormone in ovine plasma using biotin-streptavidin amplification.

To determine follicle-stimulating hormone (FSH) concentration in ovine plasma, a second-antibody enzyme immunoassay using biotin-streptavidin amplification (BS-EIA) was developed and was validated by comparison with a routine radioimmunoassay (RIA). Ovine FSH was labelled with D-biotinyl-epsilon-aminocaproic acid-N-hydroxysuccinimide ester (biotin-7-NHS). The minimum and maximum detection limits were 0.40 ng mL(-1) and 25.0 ng mL(-1) respectively in the BS-EIA. Plasma samples from three superovulated ewes were measured for FSH by both BS-EIA and RIA. Correlation between values obtained by BS-EIA and RIA was 0.86 (n = 106), and the linear regression had a slope of 0.88 and an intercept of -0.07 (R2 = 0.74). The baseline of BS-EIA was slightly lower than that of RIA (0.69 ng mL(-1) v. 1.10 ng mL(-1)). The intra-assay and inter-assay coefficients of variation in BS-EIA were 13.8% and 16.7% (n = 106) respectively. The recovery rates were 104.8+/-2.7% (mean+/-s.e.m., n = 14). Changes in plasma FSH concentration from superovulated ewes evaluated by BS-EIA corresponded well with the results of routine RIA.

Animals↗
PubMed1997

Effects of prenatal treatment with tritiated water on the developing brain in mouse.

Pregnant mice were injected intraperitoneally with various doses of tritiated water on embryonic day 13. The litters received total cumulative absorbed beta-irradiation to a dose of 0, 0.1, 0.2, 0.4 or 0.8 Gy. We found that 0.4 Gy beta-irradiation caused a significant reduction in brain weight but not in body weight among 8-week-old mice. The highest dose (0.8 Gy) inhibited both body and brain development. A quantitative study showed that a significant reduction in cerebral pyramidal cells was present in the groups exposed to > or = 0.2 Gy. In tritiated, water-treated groups, the pyramidal cells reduced in a dose-dependent manner, with reductions ranging from 3 to 12%. The thickness of cerebral cortex was significantly reduced in the groups exposed to > or = 0.4 Gy. Numerical density of pyramidal cells was the most sensitive indicator of developmental disturbance of cerebral cortex manifested postnatally. No significant difference in the numerical density of Purkinje cells was found between the irradiated and control groups. These results demonstrated that the time at which the insult occurred was an important factor determining the resulting abnormalities.

Animals↗