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Biomedical subjects

H Kume

Publications and source records attributed to H Kume.

At least 91 records · Page 5Linked to original sources
PubMed1997

Effects of JTV-506, a new K+ channel activator, on airway smooth muscle contraction and systemic blood pressure.

BACKGROUND: ATP-sensitive K+ (KATP) channel activators produce relaxation of smooth muscle in many tissues. However, this wide range of effects restricts their clinical usefulness in bronchial asthma because of a reduction in systemic blood pressure. METHODS: We have now examined the effects of JTV-506, a new benzopyran derivative, on airway smooth muscle contraction and systemic blood pressure and have compared this compound with cromakalim. We measured isometric tension records from guinea-pig isolated trachea, as well as the respiratory resistance (Rrs) and systemic blood pressure in anesthetized guinea-pigs. RESULTS: JTV-506 caused a concentration-dependent inhibition of histamine-induced contraction in guinea-pig isolated tracheal smooth muscle, and was antagonized by glibenclamide. JTV-506 was 7.6-fold more potent than cromakalim. In anesthetized animals the intravenous injection of JTV-506 reduced the increase in Rrs induced by intravenous application of 5 micrograms/kg of histamine in a dose-dependent manner. 10 micrograms/kg of JTV-506 resulted in 57.0 +/- 17.9% inhibition of the increase in Rrs at 10 min. The inhibitory action on Rrs disappeared after 60 min. 10 micrograms/kg of cromakalim caused 25.4 +/- 5.8% inhibition of the increase in Rrs induced by histamine at 1 min. The ED50 values for JTV-506 and cromakalim were 6.7 +/- 3.5 micrograms/kg and 60.1 +/- 15.8 micrograms/kg, respectively (P < 0.05). Cromakalim was approximately 9-fold less potent in inhibiting the increased Rrs by histamine, and the inhibitory action lasted less than 10 min. The reduction of systemic blood pressure by JTV-506 and cromakalim (each at a dose of 10 micrograms/kg iv) was 11.3% and 21.5%, respectively (P < 0.05). CONCLUSION: JTV-506 inhibits histamine-induced contraction of tracheal smooth muscle by activation of KATP channels. This compound is more potent and longer-lasting in the suppression of histamine-induced increases in Rrs, and is less hypotensive than cromakalim. Our results suggest that this compound merits further investigation for utility as a bronchodilator in the clinic.

Animals↗
PubMed1997

[The in vitro antifungal activities of fluconazole against pathogenic yeasts recently isolated from clinical specimens].

The emergence of Candida albicans resistance to azole antifungal agents have been reported in the U. S. and Europe. We examined the in vitro antifungal activities of fluconazole against clinical isolates collected by seven investigators in three years to examine if a tendency existed toward the development of azole-resistance among fungal isolates in Japan. The following results were obtained: 1. Sensitivities to fluconazole (FLCZ) were determined for yeast-like fungi, including 113 strains isolated in 1993, 149 strains isolated in 1994 and 205 strains isolated in 1995. No significant differences in sensitivities in the three years were detected. 2. Minimum inhibitory concentrations of FLCZ were 0.1-0.78 microgram/ml for C. albicans and 3.13-25 micrograms/ml for C. glabrata. Strains with 25 micrograms/ml of FLCZ's MIC were detected; two strains of C. krusei and one strain each of C. krusei, Trichospron beigelii and Hansenula anomala. No strains with higher than 50 micrograms/ml MIC of FLCZ were detected. 3. In vitro activities of FLCZ were compared between clinical strains isolated between 1993 and 1995 and clinical strains isolated before the marketing of FLCZ (up to December 1987) or clinical yeasts isolated between 1991 and 1992. No significant differences were observed, suggesting that no tendency existed toward azole resistance among fungal strains examined.

Antifungal Agents↗
PubMed1996

Mice lacking the 65 kDa isoform of glutamic acid decarboxylase (GAD65) maintain normal levels of GAD67 and GABA in their brains but are susceptible to seizures.

The gene encoding of the 65 kDa isoform of the gamma-aminobutyric acid (GABA)-synthesizing enzyme, glutamic acid decarboxylase (GAD), GAD65, was targeted in mice by homologous recombination. Viable GAD65 -/- mice were obtained with the expected mendelian frequency and displayed no gross morphological defects. Despite the complete loss of GAD65 mRNA and protein in a homozygous mutant, there was no difference in GABA content in the brains of GAD65 +/+, +/-, and -/- mice. As for the other 67 kDa isoform (GAD67), the levels of mRNA and protein were largely unchanged by the GAD65 mutation. General behavior, including locomotor activity and performance in the Morris water maze task, appeared normal, but seizures were more easily induced by picrotoxin and pentylenetetrazol: the latencies to seizures induced by picrotoxin were shorter and the dose of pentylenetetrazol required for induction of seizures was lower.

Animals↗
PubMed1996

Familial Alzheimer's disease-linked mutations at Val717 of amyloid precursor protein are specific for the increased secretion of A beta 42(43).

In some pedigrees of familial Alzheimer's disease (FAD), three mutations of beta amyloid precursor protein (APP) have been found at the Val717 residue (to Ile, Phe, or Cly) and these mutations increase the secretion of A beta 42(43). To study the specificity of the effects of these mutations on APP processing, we transiently expressed APP genes with mutations of Val717 to Lys, Ser, Glu, or Cys in COS cells. The three familial AD-linked mutations increased the levels or ratios of A beta 42(43), whereas the secretion of A beta 40 was decreased. Other mutations irrelevant to FAD except Val717 to Lys had little effect on the ratio of A beta 42(43). Substitution to Lys decreased the secretion of A beta 42(43); substitution to Glu or Gly decreased the amount of intracellular C-terminal fragment produced by alpha-secretase, whereas it was increased by mutations to Phe, Cys, or Lys. However, the levels of secretion of soluble APP were constant, but a substitution to Glu reduced it. These results suggest a specific role of the Val717 residue in APP processing and, especially, in gamma-cleavage.

Alzheimer Disease↗
PubMed1996

A 11.5-kb 5'-terminal cDNA sequence of chicken breast muscle connectin/titin reveals its Z line binding region.

A partial 5'-region cDNA (11.5 kb) of chicken breast muscle connectin/titin encoding 3752 amino acids was sequenced. The predicted amino acid sequence contains 31 immunoglobulin C2 motifs and 10 interdomains. The sequence suggests a skeletal muscle type of connectin isoforms. Immunoelectron microscopic studies using antisera raised against several products of the cDNA fragments expressed in E. coli revealed that a region of some 800 amino acids from the N terminus of connectin is involved in its binding to the Z line in a sarcomere.

Animals↗
PubMed1996

Molecular cloning of a novel basic helix-loop-helix protein from the rat brain.

In the mammalian nervous system, several basic helix-loop-helix (bHLH) proteins have been identified that may play essential roles in neurogenesis or neural development. This paper describes a novel bHLH protein in rat brain, which has a bHLH domain highly homologous with that of MATH-2 and NeuroD. On the other hand, the amino-acid sequence of the other regions had little homology with those of the known proteins. This protein consists of 381 amino acids and was detected only in neural tissue, indicating that it has an important role specific to neuronal activities.

Amino Acid Sequence↗
PubMed1996

Molecular cloning of a partial cDNA clone encoding the C terminal region of chicken breast muscle connectin.

The cDNA sequence encoding the C terminal region of chicken skeletal muscle connectin was described. Its predicted amino acid sequence had 1,021 amino acids comprising six motif Ils (Immunoglobulin C2 domain) and five interdomains. The sequence showed 70-75% homology with that of human cardiac connectin, but 168 amino acids including one motif II were missing in chicken skeletal muscle connectin. The C terminal sequence of chicken skeletal muscle connectin reported by the previous work (Maruyama et al., 1994) was erroneous due to the accidental ligation of the cDNA clone encoding a N terminal region of connectin with a partial porin cDNA clone.

Amino Acid Sequence↗
PubMed1996

[The efficacy of neoadjuvant chemotherapy and morphological classification of invasive bladder cancer according to chemoresponse].

BACKGROUND: We investigated the propriety of neoadjuvant chemotherapy and the possibility of bladder preservation based on clinical and pathological responses in invasive bladder cancer. METHOD: Nineteen cases of invasive bladder cancer which had been subjected to two courses of neoadjuvant chemotherapy followed by radical cystectomy were analyzed. RESULTS: The overall response rate was 79% (5/19), and 7 cases (37%) had a pathological complete response (pCR). Many cases showed degeneration or necrosis of cancer cells and infiltration of lymphocytes around the original cancer sites. Foamy macrophage or fibrous change was observed in high response cases. Thickening of the bladder wall were found after chemotherapy in such cases, which led to over-staging of the CT scan. We divided invasive bladder cancers into four different types based on gross tumor appearance and histology from TUR biopsy specimen: Type 1 which has an nodularly elevating pedunculated structure: Type 2A which has an elevating nonpedunculated structure with partly papillary component and no lymph vessel invasion: Type 2B which has an elevating nonpedunculated structure with partly papillary component and marked lymph vessel invasion: and Type 3 which has a nonelevating diffuse invasive structure with CIS lesion. The therapeutic effect was greater than grade 2 in 7 cases out of 8 (88%) Type 1, 2 cases out of 3 (67%) Type 2A, no case out of 6 (0%) type 2B, and 1 case out of 2 (50%) type 3. CONCLUSION: This classification will indicate the appropriate preoperative treatment for invasive bladder cancer, and will be useful when formulating criteria for bladder preservation. In particular, Type 1 or Type 2A is chemosensitive and may be considered for bladder preservation.

Adult↗
PubMed1996

[Immunodiagnosis and blood biochemical diagnosis of visceral candidiasis and the cutoff limits of positive].

Visceral candidiasis is nonspecific in the clinical presentation and a microbiological diagnosis is often difficult to make. Currently, several techniques are available for detection of the antigen and antibody and/or fungal product. We report the results of an investigation in immunodiagnosis and blood biochemical diagnosis of visceral candidiasis and suggest the cutoff limits of positive, from these findings and those reported by others. The efficiency and specificity were 36.4% approximately 60% and 94% approximately 100% for the mannan detection kit from Kyokuto Co., Ltd. and 57.1% approximately 100% and 25% approximately 69.6% for the CAND-TEC, and 28.6% and 91.7% for PASTOREX CANDIDA. For kits using a blood biochemical assay; the efficiency and specificity were 10% approximately 56.7% and 91.4% approximately 100% with detection of D-arabinitol (cutoff limits; 20 mumol/ml < or =), and 70% approximately 75% and 91.7% approximately 100% for Fungal Index (cutoff limits; 60pg/ml < or =). We investigated the evaluation of LA test to detect candidal mannan antigen in sera obtained from experimental gastric candidiasis of mice with or without treatment. There was a good correlation between the change of the titer of mannan antigen and the severity of infections, and gastric lesions healed histopathologically 3 weeks after disappearance of mannan antigen in sera obtained from mice treated with an antifungal agent. These findings indicate that the antifungal therapy is necessary for more than 3 weeks after the candidal mannan antigen disappeared from sera.

Animals↗
PubMed1995

Localization of three fragments of connectin in chicken breast muscle sarcomeres.

Connectin (titin) links the Z line to the myosin filament in sarcomeres of vertebrate skeletal muscle. An 800 kDa fragment of alpha-connectin runs from the Z line up to the N2 line region in the I band, and the following beta-connectin portion runs up to the edge of the M line on the myosin filament in chicken breast muscle sarcomeres. Immunoelectron microscopy showed that a 400 kDa fragment following the 800 kDa fragment reaches the edge of the myosin filament and, thereafter a 1,700 kDa fragment runs to the M line on the myosin filament in chicken breast muscle sarcomeres. When stretched, the epitopes to anti-400 kDa fragment antibodies outside the myosin filament moved toward the inside of the I band.

Animals↗
PubMed1995

Taxonomic position of deep-seated, mucosa-associated, and superficial isolates of Trichosporon cutaneum from trichosporonosis patients.

Clinical isolates of Trichosporon cutaneum, the causative agent of trichosporonosis, were identified on the basis of DNA relatedness. Of the 10 strains from deep-seated and mucosa-associated infections, 9 were identified as T. asahii and 1 was identified as T. ovoides. The two superficial strains were identified as T. cutaneum and a variety of T. montevideense. These findings suggest that T. cutaneum is a heterogeneous species in clinical samples and that the causative agents of trichosporonosis exist in four or more species.

DNA, Fungal↗
PubMed1995

Role of G proteins and KCa channels in the muscarinic and beta-adrenergic regulation of airway smooth muscle.

We have examined the functional consequences of G protein coupling to calcium-activated potassium (KCa) channels using isometric tension records from guinea pig tracheal smooth muscle. After incubation with 1 microgram/ml pertussis toxin (PTX) for 6 h, the contraction response to 1 microM methacholine (MCh) was suppressed by 31.7 +/- 5.0% (n = 10). Similarly, the contraction was inhibited by 29.1 +/- 5.0% (n = 6) after application of 0.1 microM AF-DX 116, an M2-selective muscarinic receptor antagonist. Cholera toxin (CTX, 2.0 micrograms/ml for 6 h), which activates the stimulatory G protein of adenylyl cyclase (Gs), also suppressed contraction by 43.9 +/- 3.3% (n = 11). The inhibitory effects of PTX, AF-DX 116, or CTX were reversed in the presence of 100 nM charybdotoxin (ChTX), a selective KCa channel inhibitor. These findings suggest that disruption of inhibitory coupling between muscarinic receptor and KCa channels mediated by PTX-sensitive G proteins, or KCa channel activation induced by Gs/adenylyl cyclase-linked processes, antagonizes muscarinic contraction. The isoproterenol concentration-inhibition curves for precontracted trachea (1 microM MCh) were shifted to the left after perfusion with PTX or AF-DX 116, and the leftward shift of the curve was blocked by ChTX. Thus direct or indirect regulation of KCa channels mediated by the inhibitory guanine nucleotide binding protein (Gi) and Gs may play a functionally important role in the mechanical antagonism by the two receptor agonists.

Adenylate Cyclase Toxin↗
PubMed1995

[Prognosis after radical surgery in prostatic cancer patients with lymph nodes metastases].

We investigated prognosis of clinically localized prostatic adenocarcinoma patients who revealed to have had lymph nodes metastases by undergoing radical surgery. Eighty six patients were operated during the last 15 years under the clinical diagnosis of A2, 9 patients, B1, 15 B2, 13 and C, 49, respectively. Total prostatectomy was done to 51, total cystoprostatectomy to 33 and total pelvic excentration to 2 patients. Of these patients, 22.2% with stage A2, 20.2% with B1, 7.7% with B2 and 43.8% with C had positive nodes and the rate of positive nodes in stage C was significantly higher than that in other stages (p < 0.01). Regarding histological differentiation, 15.4% of well, 23.7% of moderate and 51.6% of poor by differentiated had positive nodes and the rate of positive nodes in poor by differentiated was significantly higher (p < 0.01). In 2 of 21 cases whose lymph nodes were dissected to the level of the aortic bifurcation, positive nodes were detected only in the external and common iliac areas. These two cases were missed, i.e., "false negative" if limited nodes dissection was performed. All patients with positive nodes were treated with hormonal therapy. The 5-year cancer specific survival rate of patients with positive (n = 27) and negative (n = 59) nodes were 66.4% and 92.4%, respectively. The prognosis of patients with positive nodes were significantly worse than that of patients with negative nodes (p < 0.001). Among 27 patients with positive nodes, significant prognostic factor was not number or extent of positive nodes, but histological differentiation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1995

Inhibition of pituitary adenylate cyclase activating polypeptide induced relaxation of guinea-pig tracheal smooth muscle by charybdotoxin.

The aim of the present study was to investigate whether or not charybdotoxin (CAS 95751-30-7, ChTX), a selective and potent Ca(2+)-dependent K+ channel blocker, inhibits the relaxation of guinea-pig tracheal smooth muscle induced by pituitary adenylate cyclase activating polypeptides with 27 residues (PACAP27) and with 38 residues (PACAP38). Two forms of PACAP were discovered in hypothalamic tissues, and are known to increase the tissues cyclic AMP levels and to be independent of beta-adrenoceptors. The relaxant effects of these polypeptides were evaluated by measuring the isometric tension of tracheal smooth muscle of guinea-pig in vitro. Both forms of PACAP showed dose-dependent relaxant effects. The pD2 of PACAP27 was 7.01 +/- 0.04 and that of PACAP38 was 6.43 +/- 0.05. ChTX (10(-12)-3 x 10(-9) mol/l) did not affect the resting tension of the guinea-pig tracheal smooth muscle. ChTX (10(-8) mol/l) slightly increased the tension, in some experiments being considered as a phasic tension change. ChTX (10(-8) mol/l) caused a small but significant rightward shift in the concentration-response curves of PACAP27 and PACAP38. ChTX decreased the pD2 of PACAP27 to 6.74 +/- 0.03 and that of PACAP38 to 6.25 +/- 0.04. These results suggest that cyclic AMP-mediated activation of Ca(2+)-dependent K+ channels may play an important role in the relaxation of the guinea-pig tracheal smooth muscle induced by both forms of PACAP as well as beta-agonist.

Animals↗
PubMed1995

[Involvement of G proteins between receptors and KCa channels in the regulation of airway tone by the autonomic nervous system].

The mechanical tone of the airways is regulated by the autonomic nervous system, partly via the activity of ion channels. Ca(2+)-activated K+ (KCa) channels are densely distributed on tracheal smooth muscle cells. We found that beta-adrenergic agonists can augment KCa channel activity via the alpha subunit of the stimulatory GTP-binding (G) protein of adenylyl cyclase, Gs, linked with beta-receptors, and that muscarinic agonists can suppress the activity of this channel via the inhibitory G protein of adenylyl cyclase (pertussis toxin-sensitive G protein), Gi, linked with muscarinic receptors. These results show that there is a dual regulation system of KCa channels, which involves stimulation of the two receptors. Records of isometric tension from guinea pig tracheas incubated with pertussis toxin and cholera toxin show that regulation of KCa channels mediated by Gi and Gs may be important in the mechanical antagonism by the two receptor agonists, and they show that G proteins coupling between receptors and KCa channels may be important in beta-adrenergic bronchodilation in the treatment of asthma. In a previous study in eight atopic asthmatic patients, pretreatment with a beta-agonist abolished allergen-induced bronchoconstriction with no increment in mean plasma histamine, results that are similar to those obtained with cromyolyn sodium, a membrane stabilizer. The membrane-delimited reaction may be a key process in the autonomic regulation of airway tone. In immediate asthmatic reactions (IAR), histamine release from mast cells, contraction of airway smooth muscle, and transmitter release from post-ganglionic neurons within parasympathetic ganglia are believed to be caused by membrane hypopolarization. Because activation of KCa channels leads to hyperpolarization, beta-agonists that cause membrane hyperpolarization (short acting beta-agonists) may antagonize IAR at the level of the cell membrane. In late asthmatic reactions (LAR), short-acting beta-agonists do not have marked effects. However, recent reports have indicated that long-acting beta-agonists that do not cause hyperpolarization can inhibit LAR. Cromakalim, an ATP-sensitive K+ channel activator, reduces the "morning dip" when it is given orally to patients with nocturnal asthma. These findings show that activation of K+ channels may be useful in therapy of bronchial asthma.

Adenylyl Cyclases↗