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Biomedical subjects

H Fukuda

Publications and source records attributed to H Fukuda.

At least 577 records · Page 32Linked to original sources
PubMed1995

Transient and specific expression of a cysteine endopeptidase associated with autolysis during differentiation of Zinnia mesophyll cells into tracheary elements.

Endopeptidase activities during the differentiation of Zinnia cells into tracheary elements (TEs) were examined with several peptidyl 4-methyl-7-coumarylamido (MCA) as substrates. The activity that hydrolysed carbobenzoxy-Phe-Arg-MCA (Z-Phe-Arg-MCA) at pH 5 increased in a differentiation-related manner: this activity, which was not observed in freshly isolated mesophyll cells was induced by the combination of alpha-naphthaleneacetic acid (NAA) and 6-benzyladenine (BA) that is necessary for differentiation of TEs, but not by NAA or BA alone. The activity in cells cultured in TE-inductive medium that contained both NAA and BA increased very rapidly between the 48th and 60th hours of culture, when the number of TE increased rapidly. A protease responsible for this activity with a molecular mass of 30 kDa was partially purified from cells which had been cultured in the TE-inductive medium and included many immature TEs. Strong inhibition by [L-3-trans-carboxyoxiran-2-carbonyl]-L-Leu- -agmatin (E-64), and activation by dithiothreitol (DTT) indicated that this protease belongs to a family of cysteine endopeptidases (EC 3.4.22).

Amino Acid Sequence↗
PubMed1994

Homogeneous immunoassay of antibody by use of liposomes made of a model lipid of archaebacteria.

Liposomes made of 1,2-di(3RS,7R,11R-phytanyl)-sn-glycero-3-phosphocholine (DPhyPC), which was synthesized as one of the model lipids existing in archaebacterial halophiles, showed excellent stability. Because of this high stability, DPhyPC liposomes could be constituted high ratios (50%) of N-[4-(p-maleimidophenyl) butyryl] dipalmitoyl phosphatidylethanolamine (MPB-DPPE), and consequently could bind large amounts of antigen (alpha-chymotrypsinogen A) on the liposome surface in comparison with those made of ordinary lipids, such as dipalmitoylphosphatidylcholine (DPPC). Though the characteristics of the DPhyPC liposomal membranes in lysis by the classical complement pathway were similar to those of DPPC liposomes, a high sensitivity and a low detection limit in the liposome immune lysis assay (LILA) of antibodies were attained by binding large amounts of the antigen. Further, by coupling sufficient amounts of antigen, almost all the DPhyPC liposome surface was covered with the antigen, and such liposomes showed higher resistance against non-specific lysis caused by complement activity in serum samples, which may be effective in reducing positive-false errors in LILA.

Animals↗
PubMed1994

Bulbospinal augmenting inspiratory neurons may participate in contractions of the diaphragm during vomiting in decerebrate dogs.

Contradictory results have been reported regarding the participation of bulbospinal inspiratory (BSI) neurons in vomiting contractions of the diaphragm in dogs and cats maintained at low and high end-tidal CO2 levels, respectively. To resolve this discrepancy, effects of CO2 levels on vomiting activities were observed in 159 BSI-neurons of paralyzed decerebrate dogs. About half of the BSI-neurons exhibited a vigorous burst with each fictive retch regardless of the CO2 level and 28 of 51 BSI-neurons produced a burst during the early phase of expulsion. These BSI-neurons were not concentrated in any particular area. While these results do not resolve the above contradiction, they do suggest that some BSI-neurons participate in the vomiting contraction of the diaphragm.

Abdominal Muscles↗
PubMed1994

Reconstitution of the isobutene-forming reaction catalyzed by cytochrome P450 and P450 reductase from Rhodotorula minuta: decarboxylation with the formation of isobutene.

An isobutene-forming activity was reconstituted with cytochrome P450rm and cytochrome P450 reductase purified from Rhodotorula minuta. The nonionic detergent. Emulgen 911, present in the preparation of purified P450rm, inhibited the reconstitution. Bovine serum albumin enhanced the activity of the reconstituted system. Branching of the beta carbon of the substrate carboxylic acid was important for formation of isobutene. In a comparative study with isovalerate and 3-deuterio-3-methylbutanoate, a very large isotopic effect (kH/kD = 14) was observed. This result indicates that formation of isobutene might be initiated by abstraction of hydrogen from the beta carbon of isovalerate and might be followed by decarboxylation.

Alkenes↗
PubMed1994

Inhibitory effect of imipramine on depolarization-induced increases in intracellular Ca2+ of rat cortical neurons.

We examined the effects of imipramine on the increase in intracellular Ca2+ concentration ([Ca2+]i) induced by elevated K+ in cultured neurons of rat cortex. Imipramine (100 nM-200 microM) produced a concentration-dependent inhibition of [Ca2+]i increases induced by 25 mM K+ with an IC50 value of 32 microM. Imipramine had no effect on resting [Ca2+]i levels. When the cells were incubated with imipramine in the presence of a voltage-sensitive Ca2+ channel (VSCC) blocker, either nicardipine (10 microM), verapamil (10 microM), or omega-conotoxin GVIA (1 microM), the combinations of imipramine and each blocker resulted in an additive inhibition of 25 mM K(+)-induced [Ca2+]i increases. The IC50 values were 44, 29 and 24 microM, respectively, which were similar to those found when incubating the cells with imipramine alone. The presence or the absence of imipramine (30 microM) in an incubation with Bay K 8644 (100 nM), a VSCC agonist, showed similar potentiation of the [Ca2+]i increases induced by 15 mM K+ (66 and 52%, respectively). On the other hand, when the cells were incubated with imipramine in the presence of Ni2+ (300 microM) or La3+ (0.3 microM), inorganic Ca(2+)-channel blockers, the IC50 values of inhibition of 25 mM K(+)-induced [Ca2+]i increases were much lower than with imipramine alone (3.2 and 16 microM, respectively). However, incubations with Ni2+ combined with nicardipine or verapamil resulted in an additive inhibition of 25 mM K(+)-induced [Ca2+]i increases.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1994

Positive-ion fast-atom bombardment tandem mass spectrometry of peptide nucleic acids.

The base sequence of synthetic peptide nucleic acids (PNAs), novel antisense agents, was analyzed by positive-ion fast-atom bombardment tandem mass spectrometry (FAB-MS/MS). Upon high-energy collisional activation decomposition, PNA oligomers provided apparent MS/MS product ions resulting from specific cleavage along the PNA backbone.

Base Sequence↗
PubMed1994

Meristem-specific gene expression directed by the promoter of the S-phase-specific gene, cyc07, in transgenic Arabidopsis.

A genomic clone for the cyc07 gene, which is expressed specifically at the S phase during the cell cycle in synchronous cultures of periwinkle (Catharanthus roseus) cells, was isolated. Determination of the nucleotide sequence of the clone revealed that the cyc07 gene consists of seven exons separated by six introns. Genomic Southern analysis indicated that the cyc07 gene is present as a single copy per haploid genome in periwinkle. Expression of related genes was detected in a wide range of other plants. Transgenic Arabidopsis plants were generated that expressed the gene for beta-glucuronidase (GUS) under the control of the promoter of the cyc07 gene. The tissue-specific pattern of expression directed by the promoter was investigated by analysis of GUS activity. Histochemical tests demonstrated that 589 bp of the 5'-upstream sequence of the cyc07 gene could direct specifical expression of the GUS reporter gene in meristematic tissues in transgenic plants. The spatial pattern of expression directed by the promoter was closely correlated with meristematic activity and cell proliferation, suggesting an association between the function of the cyc07 gene and cell proliferation.

Amino Acid Sequence↗
PubMed1994

Growth kinetics of animal cells immobilized within porous support particles in a perfusion culture.

The growth kinetics of anchorage-independent animal cells [mouse myeloma MPC-11 (ATCC CCL 167)] immobilized within porous polyvinyl formal resin biomass support particles (BSPs; 3 x 3 x 3 mm cubes; mean pore diameter, 60 microns) was analyzed by measuring intracellular and extracellular lactate dehydrogenase (LDH) activities in a perfusion culture. First, the intracellular LDH content of cells immobilized within the BSPs was assayed in a shake-flask culture and found to remain almost comparable to that of non-immobilized cells in the exponential growth phase under static culture. Then, cells inoculated in the BSPs were grown in a continuous stirred-tank bioreactor. Using the LDH content of non-immobilized cells, the density of immobilized cells and the numbers of leaked and dead cells were evaluated, respectively, by the intracellular LDH activity of immobilized and leaked cells and the LDH activity in cell-free culture supernatant. In the initial period, immobilized cells exhibited exponential growth at a constant apparent specific growth rate; however, the actual specific growth rate, which takes into consideration cell death and cell leakage, decreased significantly. In the stationary phase, the actual specific growth rate maintained a constant but markedly lower value than during exponential growth.

Animals↗
PubMed1994

Characterization of diazepam-insensitive [3H]Ro 15-4513 binding in rodent brain and cultured cerebellar neuronal cells.

Experiments were performed to characterize diazepam-insensitive [3H]Ro 15-4513 binding sites in discrete regions of rodent brain and cultured rat cerebellar granule cells. Scatchard analysis of [3H]Ro 15-4513 binding in the presence of 10 microM diazepam revealed that diazepam-insensitive binding sites in the rat brain were most abundant in the cerebellum, followed by the hippocampus, cerebral cortex and olfactory bulb. Diazepam-insensitive sites represented approximately 80% of the total [3H]Ro 15-4513 binding sites in the membranes of cultured rat cerebellar granule cells. The Bmax values for total [3H]Ro 15-4513 and [35S]TBPS are almost identical, and 5-6 times larger than that for [3H]diazepam in this preparation. Although some annelated [1,5-a]benzodiazepine analogues such as Ro 15-4513, ro 16-6028, flumazenil and Ro 15-3505, and an imidazothieno-diazepine, Ro 19-4603, showed high affinity for cortical and cerebellar diazepam-insensitive sites, all the annelated benzodiazepine compounds tested showed higher affinity for cerebellar diazepam-insensitive sites than cortical ones. In contrast, a pyrazoloquinoline compound, CGS 8216, and beta-carboline analogues such as beta-carboline-3-carboxylate ethyl ester (beta-CCE) and beta-carboline-3-carboxylate methyl ester (beta-CCM) exhibited higher affinity for cortical than cerebellar sites. These results suggest that diazepam-insensitive sites are heterogeneous in brain areas with respect to ligand specificity.

Affinity Labels↗
PubMed1994

Involvement of Ca(2+)-calmodulin in platelet-derived growth factor-, fibroblast growth factor-, and insulin-induced ornithine decarboxylase in NIH-3T3 cells.

Ornithine decarboxylase (ODC) was induced by platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), and insulin at doses ranging from 0.125 to 0.5 U/mL, 25 to 500 ng/mL, and 10(-8) to 10(-7) mol/L, respectively, in NIH-3T3 cells. The induction of ODC reached a plateau approximately 4 to 6 hours after addition of each mitogen. PDGF exerted a synergistic action with 10(-7) mol/L insulin until the concentration of PDGF reached 0.5 U/mL and exerted an additive action at concentrations greater than 0.5 U/mL. FGF also accelerated ODC induction by insulin (10(-7) mol/L) synergistically when it was added at doses up to 500 ng/mL. PDGF added to the intact monolayer cells caused a spike-and-plateau increase in cytosolic Ca2+ concentration ([Ca2+]i); the spike was independent of extracellular Ca2+, whereas the plateau formation was dependent on extracellular Ca2+. On the other hand, FGF caused a plateau-like increase in [Ca2+]i, exclusively dependent on extracellular Ca2+. Insulin did not affect [Ca2+]i in NIH-3T3 cells. Trifluoperazine (15 to 30 mumol/L) inhibited the induction of ODC by PDGF and FGF, but did not inhibit the effect of insulin to induce ODC. N-(6-aminohexyl)-5-chloro-1-Naphthalenesulfonamide ([W-7] 30 to 40 mumol/L) showed a more profound suppressive effect on ODC induced by PDGF and FGF than N-(6-aminohexyl)-naphthalenesulfonamide (W-5) did. There was no difference between the effects of W-7 and W-5 on ODC induction by insulin.(ABSTRACT TRUNCATED AT 250 WORDS)

3T3 Cells↗
PubMed1994

Sjögren's syndrome in the adolescent. Report of four cases.

We report three cases of Sjögren's syndrome and a case with a probable diagnosis of Sjögren's syndrome at the ages of 16 (2 cases), 17, and 18 years. Two patients were affected by systemic lupus erythematosus. All four patients showed periductal lymphocytic infiltration in the labial glands. Two of the three patients underwent parotid sialography that revealed punctate or globular sialectasis. A decrease in stimulated parotid flow rate was noted in three of the cases compared with age-matched healthy females, whereas only one patient was diagnosed as having keratoconjunctivitis sicca.

Adolescent↗
PubMed1994

Development of an ELISA assay for soluble CD35 (C3b/C4b receptor): high levels of soluble CD35 in LE-positive patients with hematological malignancies.

Malignant cells usually lack CD35 (complement receptor type 1, C3b/C4b receptor), a differentiation surface antigen. We measured soluble forms of CD35 in the plasma of normal subjects and patients with various malignant diseases. A microassay for the determination of CD35 was established based on a sandwich enzyme immunoassay using 2 monoclonal antibodies that recognize different epitopes. Soluble CD35 was not detected in any plasma samples from normal subjects or from patients with a variety of solid cancers: i.e., levels were below 20 ng/ml. On the other hand, 3 of 70 patients with hematological malignancies showed high levels of plasma CD35. The molecular mass of the soluble form was about 200 kDa, which is similar in size to membrane forms of CD35. Although the clinical conditions differed in these patients, they had high transaminase titers and detectable autoantibody. Complement titers (CH50) and the levels of membrane complement regulatory proteins were within the normal range in these patients. Although the mechanism by which it is produced remains unknown, soluble CD35 is present in significant amounts in association with immunological disorders secondary to hematological malignancies.

Enzyme-Linked Immunosorbent Assay↗
PubMed1994

Imipramine stimulates phospholipase C activity in rat brain.

We previously demonstrated that antidepressant drugs (ADs) cause Ca2+ release from inositol 1,4,5-trisphosphate-sensitive Ca2+ stores in cultured neurons of rat frontal cortex. The present study examines the mechanism by which tricyclic ADs activate phospholipase C (PLC) in rat frontal cortex. Using an exogenous substrate to measure PLC activity, we demonstrated that a tricyclic AD, imipramine, stimulated PLC activity of the frontal cortex membrane in a concentration-dependent manner. Two tricyclic ADs, desipramine and amitriptyline, also stimulated PLC activity, while Li+ or pargyline had no effect on PLC activity. Although imipramine did not activate PLC in the membrane in the absence of Ca2+, imipramine synergistically activated PLC in the presence of Ca2+. This result indicates that the mechanism of PLC activation by imipramine is different from its activation by Ca2+. Imipramine stimulated PLC activity in the cytosol of rat frontal cortex as well as in the membrane. Preincubation of the cytosol with anti-PLC-beta 1 antibody prevented the imipramine-mediated activation of PLC. However, preincubation with anti-PLC-gamma 1 or anti-PLC-delta 1 did not prevent activation of PLC. These results suggest that imipramine activates PLC-beta 1 directly without receptor or guanine nucleotide binding protein mediation.

Animals↗
PubMed1994

Surgical treatment for hypopharyngeal cysts with a side-opened direct laryngoscope.

Two cases of hypopharyngeal cyst are reported. Both cysts occurred in the piriform sinus of the hypopharynx. Histopathological examination indicated that both were retention cysts. These cysts were removed by laryngomicrosurgical technique using a side-opened direct laryngoscope. In the cyst with a distinct base, a laryngomicrosurgical snare was used for removal. In the wide-based cyst, the mucous membrane around the cyst was incised with an electrosurgical instrument and then detached to facilitate removal. In this paper, we describe our surgical procedure for removing hypopharyngeal cysts and discuss the causes of such cysts.

Cysts↗
PubMed1994

Primary small cell carcinoma of the larynx.

Small cell carcinoma is a rare tumor of the larynx. We present such a case in a 78-year-old female. The histopathological diagnosis at the time of laryngomicroscopic biopsy was squamous cell carcinoma, upon which basis we initially chose surgical treatment. The surgical specimen, however, revealed small cell carcinoma. Despite the administration of radiotherapy and chemotherapy, the patient died 9 months after initial presentation. We believe that this case illustrates the need for a sufficiently large biopsy specimen in order to arrive at the correct histopathological diagnosis when small cell carcinoma of the larynx is present, and that immunohistochemistry and electron microscopy should be performed to aid the diagnosis.

Aged↗
PubMed1994

Flow cytometric analysis of nuclear DNA content in tongue squamous cell carcinoma: relation to cervical lymph node metastasis.

The relationship between DNA ploidy and the incidence of cervical lymph node metastasis in 36 patients with tongue squamous cell carcinoma (SCC) was investigated. The aneuploidy rate of tongue carcinomas was 15/36 (42%), and the mean DNA index (DI) was 1.23, with a range from 0.87 to 3.54. Histologically identified cervical lymph node metastasis was observed in 11 cases, and the incidence of the cervical lymph node metastasis was significantly (P < 0.02) higher in the aneuploid cases (8/15) than in the diploid cases (3/21). Recurrence of the primary lesions was seen in nine cases 0.3-2.5 years after the initial treatment. No obvious difference in the incidence of the recurrence was noted, however, between the diploid (5/21) and the aneuploid (4/15) cases. These results indicate a significant relationship between aneuploidy and incidence of the regional lymph node metastasis, in contrast to the absence of a positive relationship between aneuploidy and recurrence of tongue SCC.

Aneuploidy↗