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Biomedical subjects

H Okayama

Publications and source records attributed to H Okayama.

At least 163 records · Page 9Linked to original sources
PubMed1988

K channels of human alveolar macrophages.

The activation of macrophages has been reported to be associated with Ca-activated K permeability change. In order to study this permeability change in human alveolar macrophages, we examined alveolar macrophages electrophysiologically at a single channel level. We observed two types of Ca-activated K channel currents having conductances of 218 +/- 2 and 32 +/- 0.6 picosiemens in symmetrical 154 mmol/L KCl solutions. The characteristics, such as voltage dependency and Ca sensitivity, as well as channel conductance, were different between these two types of channel currents. Quinine (a blocker of Ca-activated K conductance), 0.5 mmol/L, reduced these channel currents by 45 +/- 8% and 31 +/- 8%. Quinine, 0.5 mmol/L, also inhibited chemiluminescence and leukotriene B4 release by 82 +/- 6 to 88 +/- 3% and 88 +/- 2%, respectively. These results suggest the presence of two types of Ca-activated K channels, which may be related to the release of inflammatory mediators from human alveolar macrophages.

Calcium↗
PubMed1988

Does diffuse intimal thickening in human coronary artery act as a diffusion barrier to endothelium-derived relaxing factor?

We investigated the effect of intimal thickness in human coronary artery on the endothelium-dependent relaxation. Histamine (in the presence of cimetidine), substance P and A23187 potently relaxed arterial rings with intima thinner than 200 microns. However, those relaxations diminished progressively in the artery with intimal thickness of 200-400 microns, and disappeared at the thickness greater than 400 microns. These results suggest that diffuse intimal thickening greater than 200 microns may inhibit the diffusion of endothelium-derived relaxing factor.

Biological Factors↗
PubMed1988

Bronchoalveolar lavage during inhalation provocation test in a case of farmer's lung disease.

Bronchoalveolar lavage (BAL) was performed in order to reveal inflammatory immune processes during inhalation provocation test in a patient with farmer's lung disease. Three hours after inhalation challenge the patient showed dyspnea and an increase in body temperature to 38.9 degrees C, restrictive and obstructive impairment, and a decrease in peripheral lymphocytes from, 2.8 x 10(3)/mm3 to 1.8 x 10(3)/mm3, although peripheral granulocytes increased from 4.4 x 10(3)/mm3 to 10.3 x 10(3)/mm. BAL fluid at that time showed increases in lymphocytes, granulocytes and macrophage, as well as proteins and complements, compared with that before the inhalation test. These findings indicate that with inhalation challenge in a patient with farmer's lung disease, inflammation increases vascular permeability while protein loss is followed by an increase in lymphocytes, granulocytes and macrophage; the lymphocytes migrate to the lung from peripheral blood.

Aged↗
PubMed1987

Bronchodilating effect of intravenous magnesium sulfate in bronchial asthma.

The bronchodilating effect of magnesium sulfate (MgSO4) was studied in ten asthmatic patients with mild attacks. In five patients, 0.5 mmol/min of MgSO4 was administered intravenously for 20 minutes, and the time courses of respiratory resistance, forced vital capacity, and forced expiratory volume at 1 s were studied. In another five patients, MgSO4 dose-response curves were obtained. Soon after administration began, MgSO4 relieved bronchoconstriction in a dose-dependent manner. Maximum responses (mean +/- SE) of respiratory resistance, forced vital capacity, and forced expiratory volume were 71% +/- 3%, 117% +/- 5%, and 118% +/- 1% of initial values, respectively, and were similar to the effects of additional albuterol inhalation. The infusion of MgSO4 also improved dyspnea and piping rales in three other asthmatic patients with a severe attack. We conclude that intravenous infusion of MgSO4 produces a rapid and marked bronchodilation in both mild and severe asthma and may be a unique bronchodilating agent.

Adult↗
PubMed1987

Complementation of the UV-sensitive phenotype of a xeroderma pigmentosum human cell line by transfection with a cDNA clone library.

In previous work, a xeroderma pigmentosum cell line belonging to complementation group C was established by transformation with origin-defective simian virus 40. We now report the complementation of the UV sensitivity of this cell line by gene transfer. A human cDNA clone library constructed in a mammalian expression vector, and itself incorporated in a lambda phage vector, was introduced into the cells as a calcium phosphate precipitate. Following selection to G418 resistance, provided by the neo gene of the vector, transformants were selected for UV resistance. Twenty-one cell clones were obtained with UV-resistance levels typical of normal human fibroblasts. All transformants contained vector DNA sequences in their nuclei. Upon further propagation in the absence of selection for G418 resistance, about half of the primary transformants remained UV-resistant. Secondary transformants were generated by transfection with a partial digest of total chromosomal DNA from one of these stable transformants. This resulted in 15 G418-resistant clones, 2 of which exhibited a UV-resistant phenotype. The other primary clones lost UV resistance rapidly when subcultured in the absence of G418. Importantly, several retained UV resistance under G418 selection pressure. The acquisition of UV resistance by secondary transformants derived by transfection of DNA from a stable primary transformant, and the linkage between G418 and UV resistances in the unstable primary transformants, strongly suggests that the transformants acquired UV resistance through DNA-mediated gene transfer and not by reversion.

Cell Line↗
PubMed1987

High-efficiency transformation of mammalian cells by plasmid DNA.

We describe a simple calcium phosphate transfection protocol and neo marker vectors that achieve highly efficient transformation of mammalian cells. In this protocol, the calcium phosphate-DNA complex is formed gradually in the medium during incubation with cells and precipitates on the cells. The crucial factors for obtaining efficient transformation are the pH (6.95) of the buffer used for the calcium phosphate precipitation, the CO2 level (3%) during the incubation of the DNA with the cells, and the amount (20 to 30 micrograms) and the form (circular) of DNA. In sharp contrast to the results with circular DNA, linear DNA is almost inactive. Under these conditions, 50% of mouse L(A9) cells can be stably transformed with pcDneo, a simian virus 40-based neo (neomycin resistance) marker vector. The NIH3T3, C127, CV1, BHK, CHO, and HeLa cell lines were transformed at efficiencies of 10 to 50% with this vector and the neo marker-incorporated pcD vectors that were used for the construction and transduction of cDNA expression libraries as well as for the expression of cloned cDNA in mammalian cells.

Animals↗
PubMed1987

Neural control of contraction in isolated submucosal gland from feline trachea.

To determine the autonomic innervation to myoepithelial cells of submucosal gland, we applied electrical field stimulation (FS) to the intrinsic nerves in isolated submucosal glands from feline tracheae. FS induced contraction that was voltage or frequency dependent and abolished by pretreatment with tetrodotoxin. DMPP (1,1-dimethyl-4-phenylpiperazinium iodide) did not produce any significant contraction, and pretreatment with hexamethonium did not alter the response to FS. Atropine inhibited the contractile response to FS and neostigmine augmented the response to FS. Serotonin also augmented the response to FS, whereas the response to methacholine remained unchanged in the presence of serotonin. Phentolamine reduced the response to FS by 15% of control, whereas propranolol induced no significant changes in the response to FS. No significant inhibitory responses were observed by FS. Our findings indicate that the contraction of tracheal submucosal glands is mediated mainly by cholinergic nerves via muscarinic receptors and in small part by adrenergic nerves via alpha-receptors, and serotonin potentiates the contractile response to FS at the postganglionic nerve.

Adrenergic Fibers↗
PubMed1987

Effect of substance P on mucus secretion of isolated submucosal gland from feline trachea.

To elucidate how substance P (SP) produces submucosal gland secretion, we examined the effects of SP on the glandular contractile response and 3H-labeled glycoconjugate release in isolated submucosal glands from feline tracheae. SP (10(-12) to 10(-4) M) produced dose-dependent increases in the contractile response, and the maximal tension induced by SP was approximately 70% of the response to methacholine. SP-induced contraction is blocked completely by atropine and augmented by neostigmine. Pretreatment with hemicholinium 3, an acetylcholine synthesis inhibitor, inhibited the contractile response to SP. Pretreatment with tetrodotoxin did not inhibit the contractile response to SP. Capsaicin induced tension of a magnitude similar to that of SP. SP (10(-7) M) produced a significant increase (74% above control) in radiolabeled glycoconjugate release from isolated glands, whereas SP had no significant effects on glycoconjugate release from tracheal explants, probably because of epithelial suppression. Atropine abolished SP-evoked glycoconjugate release in isolated glands. Our findings indicate that 1) SP induces glandular contraction, which is related to the squeezing of mucus in the ducts and secretory tubules, 2) SP stimulates radiolabeled glycoconjugate release in isolated submucosal gland, probably involving mucus synthesis and/or cellular secretion, and 3) these two actions are mediated by a peripheral cholinergic mechanism.

Animals↗
PubMed1987

Late asthmatic response to Ascaris antigen challenge in dogs treated with metyrapone.

We developed an experimental dog preparation that shows a biphasic bronchoconstriction after allergen exposure. After anesthetization, the dogs were intubated with endotracheal tubes and manually ventilated. Respiratory resistance (Rrs) was measured by the forced oscillation method at 3 Hz. Ascaris suum, diluted from 10(-5) to 10(-2) of the extract, was inhaled during tidal breathing for 5 min. One hour before antigen challenge, 10 dogs received 70 mg/kg of metyrapone (cortisol synthesis inhibitor), and 2 h after antigen challenge 35 mg/kg of metyrapone were injected intravenously. In another 10 dogs, metyrapone was not administered. After the maximal increase in Rrs had been assessed (immediate asthmatic response), Rrs increased again 4 to 6 h after antigen challenge in 8 of the 10 dogs treated with metyrapone (late asthmatic response, 443 +/- 282% mean +/- SD of initial Rrs), which was significantly higher than Rrs 6 h after antigen challenge (124 +/- 41%) in dogs without metyrapone (p less than 0.01). In another 5 dogs, ragweed challenge with metyrapone caused no change in Rrs. Bronchoalveolar lavage at the time of the late response revealed a significant correlation between late asthmatic response and neutrophil accumulation (p less than 0.01) in all dogs. We conclude that cortisol depletion augments the occurrence of the late response. The present dog model may be a useful tool for study of the late response in bronchial asthma.

Airway Resistance↗
PubMed1986

Cloning and sequencing of cDNA of bovine N-acetylglucosamine (beta 1-4)galactosyltransferase.

Galactosyltransferases constitute a family of enzymes, each member of which transfers galactose from UDPgalactose to a specific acceptor molecule, generating a specific galactose-acceptor linkage. Two synthetic oligonucleotides, 27mer and 21mer, were synthesized, based on the amino acid sequences of two peptides derived from bovine milk N-acetylglucosaminide (beta 1-4)galactosyltransferase (EC 2.4.1.90), and used as hybridization probes to isolate cDNA clones for galactosyltransferase from a bovine mammary gland cDNA library. One of the plasmids, designated pLbGT-1, contains an insert of about 3.7 kilobases that hybridizes to both of the probes and encodes the amino acid sequences of five peptides obtained from bovine milk (beta 1-4)galactosyltransferase. A second plasmid, designated pLbGT-2, contains an insert of about 4.1 kilobases that hybridizes to only the 27mer and that encodes a polypeptide containing the sequence of the carboxyl-terminal 120 residues identical to the peptide encoded by pLbGT-1; the rest of the protein sequence, however, does not contain known sequences from bovine galactosyltransferase. The two cDNAs contain a 3'-untranslated region of about 2.7 kilobases that includes two copies of the Alu-equivalent sequences. pLbGT-1 and pLbGT-2 hybridize to mRNAs of various sizes obtained from the bovine and rat mammary gland and the human mammary tumor cell line MCF-7, with the longest mRNA from each species being around 4.5 kilobases. The results show that pLbGT-1 is a cDNA clone for bovine (beta 1-4)galactosyltransferase, and pLbGT-2 encodes a protein that is structurally and may be functionally related to transferases.

Amino Acid Sequence↗
PubMed1986

Central and peripheral airways as determinants of ventilatory function in patients with chronic bronchitis, emphysema, and bronchial asthma.

We studied central and peripheral airways as determinants of ventilatory function in patients with chronic bronchitis (CB), bronchial asthma (BA), and emphysema (CPE), which were identified using the selective alveolobronchogram (SAB) (see reference 14). First, the relationship between SAB and morphologic findings in the airway was examined in 16 autopsy lungs. The irregularity indices of both central (C-II) and peripheral airways (P-II), obtained from SAB, showed a significant correlation with pathologic abnormalities in both airways (p less than 0.01). Second, SAB were obtained in 38 CB, 25 BA, and 62 CPE patients in whom pulmonary function tests were performed. In CB, C-II were significantly correlated with P-II (p less than 0.001). In CB, inspiratory lung resistance (RL) was significantly correlated with P-II (p less than 0.001) and with C-II (p less than 0.01), and FEV/VC% was significantly correlated with P-II (p less than 0.0001) but not with C-II. In BA and CPE, little correlation was observed between any SAB parameter and RL or FEV/VC%. We conclude that the present SAB parameters represent morphometric abnormalities of the central and peripheral airways, and that in CB, peripheral airway abnormalities correlated well with chronic airway obstruction.

Adult↗