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Biomedical subjects

K Yoshimura

Publications and source records attributed to K Yoshimura.

At least 523 records · Page 29Linked to original sources
PubMed1984

Studies of Angiostrongylus cantonensis in two experimental hosts.

Lung infection with Angiostrongylus cantonensis was established in experimentally infected Indian soft-furred rats (Millardia meltada) and Indian spiny mice (Mus platythrix). Pulmonary arterial migration occurred earlier (at day 20 after infection) in M. meltada than in Wistar rats. M. meltada and M. platythrix could serve as useful animal models for comparative studies of mechanisms determining host specificity of A. cantonensis.

Angiostrongylus↗
PubMed1984

Ultrastructural evidence for eosinophil-mediated destruction of Angiostrongylus cantonensis transferred into the pulmonary artery of non-permissive hosts.

Ultrastructural and cytochemical analyses were carried out on cellular reactions to the young adult worms of Angiostrongylus cantonensis surgically transferred into the pulmonary arteries of permissive (rat) and non-permissive (rabbit and guinea-pig) hosts. In permissive hosts, no appreciable cellular reactions could be found around worms throughout the course of the observations. By contrast, the infiltration of neutrophils along with eosinophils was observed around worms in non-permissive hosts even at early stages (days 2 to 4). At day 7 and later, the prominent degranulation (solubilization of the whole granule or the matrix alone with preserved crystalloid, tubulovesicular structure formation, and vacuole formation containing lysosomal contents, etc.) of eosinophils, and subsequent release of the lysosomal contents on to the worm surface were noted. Discharge of large amounts of peroxidase on to the worm surface was also demonstrated. The worms were thus damaged and their cuticular fragments were frequently found removed. In addition to this, degenerative changes, such as lipid-droplet and vacuole formations, were detectable in the hypodermis, somatic musculature and intestine of the parasites transferred into the non-permissive hosts, as early as day 4 after transfer. These data suggest that eosinophils would serve as a potential effector cell for killing of pulmonary arterial A. cantonensis in non-permissive hosts.

Angiostrongylus↗
PubMed1984

Construction of a promoter-probe vector for a Bacillus subtilis host by using the trpD+ gene of Bacillus amyloliquefaciens.

The trp gene cluster of Bacillus amyloliquefaciens was found to be structurally similar to that of the Enterobacteriaceae. The translation termination codon of the putative trpE gene and the initiation codon for the putative trpD gene overlap at the trpE-trpD junction, and a promoter for the putative trpC gene is suggested to exist. A promoter-probe vector of Bacillus subtilis, pFTB281, was constructed with a DNA fragment of B. amyloliquefaciens, complementing the trpC and trpD mutations of B. subtilis, a 42-base-pair DNA fragment of M13mp7, and the larger EcoRI-PvuII fragment of pUB110, which confers an autonomous replication function and the kanamycin-resistance phenotype to the chimeric plasmid. pFTB281 has BamHI, EcoRI, and SalI cloning sites in the 5'-upstream portion of the protein-coding region of the putative trpD gene, and the insertion of a certain DNA fragment at any of these sites allowed the plasmid to transform a trpD mutant of B. subtilis to the TrpD+ phenotype. DNA fragments showing the promoter function for the trpD gene were obtained from B. amyloliquefaciens and Saccharomyces cerevisiae chromosomes and rho 11 and lambda phage DNAs, but rarely from the DNAs of Escherichia coli and pBR322.

Amino Acid Sequence↗
PubMed1984

Mechanism of regulation of amylase release by alpha- and beta-adrenergic agonists in rat parotid tissue.

The effect of forskolin and isobutyl-methylxanthine on amylase release and cyclic AMP accumulation by alpha- and beta-adrenergic agonists was studied in rat parotid slices. A small increase in cyclic AMP by beta-adrenergic agonists was sufficient for maximum stimulation of amylase release (Yoshimura et al., 1982a), but a similar increase in cyclic AMP by forskolin did not stimulate the maximum amount of amylase release. The amount of amylase release and cyclic AMP changed in parallel when lower doses of isobutyl-methylxanthine were used, but higher doses of isobutyl-methylxanthine further increased cyclic AMP without causing a significant increase in amylase release. Amylase release stimulated to its maximum by isobutyl-methylxanthine was much lower than that by isoproterenol. These results suggest that cyclic AMP is not the only chemical correlate for the activation of amylase release by beta-adrenergic agonists. The effect of phenylephrine and methoxamine on amylase release was augmented by either forskolin or isobutyl-methylxanthine, but the effect of methacholine was not. Phenylephrine increased the cyclic AMP concentration under the same conditions, but methoxamine did not. The inhibition of the effect of phenylephrine plus forskolin on cyclic AMP accumulation by propranolol was almost complete and stereospecific, but the inhibition of their effects on amylase release was incomplete and not stereospecific. Synergism of amylase release was observed in the effect between methoxamine and dibutyryl-cyclic AMP. These results suggest that the augmentation of the effect of alpha-adrenergic agonists on amylase release by forskolin or isobutyl-methylxanthine cannot be explained only on changes in cyclic AMP and that some other factor in collaboration with cyclic AMP may participate in the regulation of amylase release by alpha-adrenergic agonists.

1-Methyl-3-isobutylxanthine↗
PubMed1984

Effects of elevated-hematocrit levels on pulmonary circulation in conscious sheep.

We investigated the effects of stepwise hematocrit (Ht) increase on pulmonary circulation in conscious sheep (n = 7). The Ht was increased by an isovolumic exchange transfusion of blood with centrifuged red cells. By increasing the Ht-values, both systemic (PSA) and pulmonary artery pressures (PPA) were increased, with the degree of PPA increment greater than that of PSA. Cardiac output (CO) was slightly decreased by increasing the Ht. Also, A-V difference values of blood oxygen tension were reduced with elevation of the Ht values. The ratio of the right ventricular work rate (RVW) to the left one (LVW), RVW/LVW, was shown to increase remarkably with increased Ht. This increase was considered to be supporting evidence for the right ventricular hypertrophy in high altitude acclimatization. A strong positive correlation was observed between Ht and blood viscosity. It was thus confirmed that Ht effect was greater in pulmonary circulation than in systemic circulation.

Altitude↗
PubMed1984

[Pharmacological studies of a new sleep-inducer, 1H-1,2,4-triazolyl benzophenone derivatives (450191-S) (I). Behavioral analysis].

The behavioral effects of 450191-S and its metabolites were investigated in mice, rats, cats and rhesus monkeys, and they were compared with those of related benzodiazepines (BDZ) such as diazepam and nitrazepam. Oral administration of 450191-S consistently caused sedation without excitability in mice and rats, and it was only 1/2 to 1/266 as potent as the BDZ in producing motor incoordination as assessed by traction, rotarod performance and inclined screen tests in mice, induced much less ataxia in cats and monkeys, and inhibited respiration in anesthetized cats. The locomotor activities of mice and rats measured by Animex and the open field test were not affected by 450191-S, but rearing and preening decreased with 450191-S as with the BDZ. 450191-S was equipotent with nitrazepam and 2 to 6 times more potent than diazepam and estazolam in potentiating chlorprothixene-induced hypnosis and thiopental-Na-induced anesthesia. These effects were not different with successive 14-day administration of 450191-S. Anti-pentylenetetrazol, picrotoxin and bicuculline convulsions of 450191-S had the same potency as nitrazepam, but caused much less anti-electroshock convulsion than the BDZ. 450191-S had potent antianxiety activity as observed by anti-aggressive and anti-conflict activities and had almost the same effect as diazepam on operant behavior. The metabolites M-1, M-2, M-A and M-3 showed approximately the same potency as 450191-S in inducing anesthetic potentiation and antianxiety activity, but they were much more potent in causing disturbance of the somatic functions. These results indicate that 450191-S possesses inhibitory effects on the central nervous system, including a potent sleep-inducing effect, and is characterized by markedly weak muscle relaxant activity and motor incoordination.

Aggression↗
PubMed1984

[Pharmacology of a new sleep inducer, 1H-1,2,4-triazolyl benzophenone derivative, 450191-S (II). Sleep-inducing activity and effect on the motor system].

The sleep-inducing activity and effect on the motor system of the 1H-1,2,4-triazolyl benzophenone derivative 450191-S were examined behaviorally, electroencephalographically and electro-physiologically with various species of animals and were compared with those of diazepam, nitrazepam, estazolam and triazolam. In the rhesus monkey, rabbit and rat with chronically indwelling brain electrodes, 0.6 to 3 mg/kg, p.o. of 450191-S caused a shorter latency of sleep onset, an increase of and a stable continuity of slow wave deep sleep (SWDS) with higher amplitude, and the appearance of clear spindle bursts in the slow wave light sleeping (SWLS) state with little muscle relaxation. Animals treated with nitrazepam and/or estazolam showed a smaller increase in SWDS and its unstable continuity with remarkable disturbance of gait. The doses needed to induce sleep in the rhesus monkey were 0.6 to 1 mg/kg p.o. for 450191-S, 3 mg/kg for nitrazepam, 1 mg/kg for estazolam and 0.3 mg/kg for triazolam. The cat treated with 450191-S showed the phenomena caused by benzodiazepines (BDZ), i.e., behavioral excitation and decrease of frequencies in the hippocampal theta waves. The suppressive effects of 450191-S on the EEG arousal reaction and/or blood pressure elevation induced by hypothalamic stimulation in the rabbit suggested that the inhibitory effects acted on the posterior hypothalamus to the limbic system. The inhibitory effect of 450191-S on the amygdaloid kindling in the rat was as potent as those of diazepam and nitrazepam. Successive daily oral administration of both 3 mg/kg of 450191-S and/or 3 to 6 mg/kg of nitrazepam for 15 days in the rabbit caused slight decrease of SWDS and increase of fast wave (REM) sleep (FWS). During the withdrawal period of both compounds, a slight but insignificant increase in the waking state was noticed for 1 to 2 days, but not a rebound increase of FWS. Intravenously administered 450191-S showed the same action as BDZ on the spinal reflex and the dorsal root potential of the rat; it particularly acted on the crossed extensor reflex in the same manner as the commercial BDZ sleep inducers.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1984

[Clinical study on tissue polypeptide antigen (TPA) as a tumor marker].

We evaluated whether assay of tissue polypeptide antigen (TPA) in sera is valuable for the determination of cancer stages compared to other tumor markers such as CEA, AFP, beta2-microglobulin, ferritin, and elastase-1. The study population consisted of cancer patients (33 gastric cancers, 7 colo-rectal cancers and 15 hepatomas), 169 patients with benign gastro-enteric diseases and 72 healthy volunteers. The percentage of positive cases for TPA (higher than 200 u/l) was 61% in gastric cancer, 71% in colo-rectal cancer and 87% in hepatoma. In certain non-cancerous conditions, such as gastric ulcer (active stage), acute hepatitis and chronic hepatitis, the TPA levels were increased over the level of healthy volunteers. There was no significant correlation between TPA and the other tumor markers. Our study suggests that TPA may be useful in the identification and evaluation of cancer patients.

Adolescent↗
PubMed1984

[Pharmacological studies on drug dependence. (III): Intravenous self-administration of some CNS-affecting drugs and a new sleep-inducer, 1H-1, 2, 4-triazolyl benzophenone derivative (450191-S), in rats].

The present study examined comparative self-administration of some typical CNS-affecting drugs with a new sleep-inducer, 450191-S, in rats, Most animals self-administered both methamphetamine and cocaine in an extremely stable and invariable fashion with cycles of alternating responding and non-responding periods during the day and at night. Response frequency increased in proportion to a fixed-ratio value. An initial increase in response rate followed by cessation of the responding was observed during extinction. Sixty-five percent of the rats tested self-administered morphine in a relatively variable and less stable fashion. Total daily morphine intake was directly related to the unit dose. Eighty-three percent of the rats self-administered pentazocine. Fifty and sixty-four percent of the rats maintained self-administration of phenobarbital and diazepam, respectively, with higher intake at night than during the day. Responding persisted at a low rate for several days during extinction. Abrupt withdrawal of 450191-S caused the same slight weight loss and moderate decrease in food intake as those seen with diazepam and nitrazepam, and cross-physical dependence between 450191-S and diazepam was found. Self-administration of 450191-S at 0.5-2.5 mg/kg/infusion was observed with 2 out of 11 rats, which was much less than that found with diazepam. These results suggest that 450191-S possesses little, if any, drug dependence liability of the tranquilizer type.

Animals↗
PubMed1983

A new immunoglobulin marker.

In an examination of 16 human immunoglobulin lambda-light chains, one was found to have amino acid substitutions which have not previously been reported for the constant region of the lambda-chains. It involved in two positions: an arginine instead of lysine at position 130, and a leucine for glutamine at position 195 (Sh numbering (1) ). The structural variation is tentatively designated as "Is" marker.

Amino Acid Sequence↗
PubMed1983

Analysis of deposits on high water content contact lenses.

Deposits on soft contact lenses of high water content were investigated morphologically and chemically and compared with those on conventional soft contact lenses of poly (2-hydroxyethyl methacrylate). The material of the lenses examined in this investigation was the crosslinked copolymer of methyl methacrylate and N-vinylpyrrolidone with a water content higher than 70%. Morphologically, the deposits on the lenses with high water content were found to have no characteristics distinguishable from those on conventional lenses. By the electron microscopic observation of the cross section of a lens that had become opaque, it was confirmed that the deposit was on the lens surface and that no deposit was within the lens. Some spots on the lenses were recognized as colonies of microorganisms, but the majority of the spots had no involvement by microorganisms. Surface analysis with Fourier transform infrared spectrometer (FT-IR) confirmed that the main component of the filmy deposit was protein. Protein was detected in most of the deposits. The amino acid compositions of the proteins were found to be close to that of lysozyme. From the elemental analysis of several spots, silicon, aluminum, iron, and some other elements were detected. The structural analysis of some spots by a laser Raman microprobe (MOLE) revealed the existence of lipids. In several cases, the deposits were found to have grown around a defect of the lens surface. A mechanism for the formation of deposits is suggested.

Amino Acids↗
PubMed1983

Construction of a Bacillus subtilis cloning vehicle with heterologous DNA sequence.

A cloning vehicle, pFTB91, for the Bacillus subtilis host was constructed with DNA fragments heterologous to the host chromosome. It consists of three DNA fragments: (i) chromosomal DNA of Bacillus amyloliquefaciens which complements the leuA and ilvC mutations in B. subtilis; (ii) a B. amyloliquefaciens plasmid DNA that supplies an autonomously replicating function; and (iii) a HindIII fragment of Staphylococcus aureus plasmid pTP5 that carries gene tetr, conferring the TetR phenotype. It has sufficiently low DNA homology to prevent its integration into the host chromosome in recombination-competent cells of B. subtilis. It is 9.3 kb, and approx. 10 copies are present per chromosome. The SalI and KpnI sites in the ilvC+ and tetr genes, respectively, could be used for selection of recombinant plasmids by insertional inactivation. The plasmid has unique sites for EcoRI, PstI, and XbaI.

Bacillus↗