Biomedical subjects

T Nishino

Publications and source records attributed to T Nishino.

At least 19 recordsLinked to original sources

PubMed1992

Light product of photoreactive 6-azido-FAD bound to deflavo-milk xanthine oxidase.

Xanthine oxidase from milk was reconstituted with the photoreactive flavin, 6-azido-FAD. While irradiation of the reconstituted enzyme under anaerobic conditions yielded 6-amino-FAD as a light product, aerobic irradiation resulted in formation of an unknown product, which gave the enzyme almost the same activity as that of the native enzyme. The light product could be extracted from the enzyme without breakdown and was found to be highly fluorescent. Upon treatment with phosphodiesterase, this light product was converted to the FMN form. The absorption spectrum of the FMN form has a peak at 464 nm, a shoulder at 450 nm in the visible region, and two peaks at 260 and 298 nm in the UV. Irradiation of free 6-azido-3-methyllumiflavin in the presence of a saturating concentration of oxygen yielded a light product whose absorbance and fluorescence spectra were very similar to those of the light product extracted from the enzyme, suggesting that the two had undergone some common photochemical change at the same place in the isoalloxazine ring. Analysis of the light product of 6-azido-3-methyllumiflavin with 1H NMR and FAB mass spectrometry suggested its possible structure with a new five-membered ring, C(6) = N-O-CH = C(7), adjacent to the benzene ring of the flavin.

Anaerobiosis↗

PubMed1992

Effects of topical nasal anaesthesia on shift of breathing route in adults.

The position of the soft palate is known to determine the breathing route, but the physiological mechanisms that bring about a shift from nasal to oral breathing are unclear. To test the hypothesis that activation of receptors in the nasal passage may be involved in reflex initiation of oral breathing after nasal obstruction, we investigated respiratory responses to nasal occlusion before and after topical lignocaine anaesthesia of the nasal passages. Eleven volunteers were fitted with custom-made partitioned face masks, which separated nasal and oral passages. Air flow through each passage was detected by changes in airway pressure and carbon dioxide concentration. Nine subjects were habitual nasal breathers both before and after topical anaesthesia with 4% lignocaine. Among these subjects, the time to initiate oral breathing in response to nasal occlusion was significantly shorter before anaesthesia than afterwards (mean 4.4 [SD 2.5] vs 10.8 [7.4] s, p less than 0.01). Similarly, the time to resume nasal breathing after release of nasal occlusion was significantly shorter before topical anaesthesia than afterwards (6.9 [4.9] vs 12.1 [7.8] s, p less than 0.01). Topical anaesthesia did not affect respiration rate, end-tidal carbon dioxide concentration, or arterial oxygen saturation. These findings suggest that in human beings sensory information from receptors in the nasal passage has an important role in controlling the shift of breathing route.

Administration, Topical↗

PubMed1992

Anticoagulant and antithrombin activities of oversulfated fucans.

Three species of oversulfated fucans having different sulfate contents (the ratio of sulfate/total sugar residues, 1.38-1.98) were prepared by chemical sulfation of a fucan sulfate (sulfate/sugar ratio, 1.28) isolated from the brown seaweed Ecklonia kurome. The anticoagulant activities of the oversulfated fucans were compared with that of a parent fucan with respect to activated partial thromboplastin time (APTT) and thrombin time (TT) in plasma. The respective activities (for APTT and TT) of the oversulfated fucans increased to 110-119% and 108-140% of the original values with increase in their sulfate content. The anticoagulant activity with respect to APTT (173 units/mg) of an oversulfated fucan (sulfate/sugar ratio, 1.98) was higher than that (167 units/mg) of heparin used as a standard. The heparin cofactor II-mediated antithrombin activity of the oversulfated fucans also increased significantly with increase in sulfate content. The maximum activity was higher than those of the parent fucan and heparin. However, the increment of the anticoagulant and the antithrombin effects gradually decreased with increase in the sulfate content of the fucans. These results indicate that the effects of the fucan sulfate are dependent on its sulfate content until a plateau is reached.

Anticoagulants↗

PubMed1992

Effects of K-76COOH (MX-1) on immune response: induction of suppressor T-cells by MX-1.

K-76COOH (MX-1), isolated from the cultured supernatant of a species of fungi imperfecti, Stachybotrys complement nov. sp. K-76, is an inhibitor of the complement component, C5. The effects of MX-1 on various immune responses were investigated. MX-1 enhanced the response of spleen cells to PHA and LPS: MX-1 at 0.01-250 micrograms/ml for PHA and at 10-250 micrograms/ml for LPS. In contrast, it inhibited the response to Con A: MX-1 at 0.01-500 micrograms/ml for spleen cells and at 100-500 micrograms/ml for thymocytes. MX-1 and IL-1 synergistically acted to enhance the Con A response of spleen and thymus cells from which accessory cells and Ia-positive cells had been removed by passing through Sephadex G-10 columns and treating with anti-Ia monoclonal antibody plus complement. T-cells pretreated with MX-1, IL-1 and Con A for 3 days suppressed not only the response of B-cells to LPS but also the production of anti-SRBC antibodies. In addition, MX-1 was found to increase CD8+ T-cells. These results suggest that MX-1 acts on T-cells to induce suppressor T-cells.

Animals↗

PubMed1992

Congenital polyneuropathy in Walker-Warburg syndrome.

Polyneuropathy was found in a patient with the Walker-Warburg syndrome. The most dominant features were the presence of extremely and tortuously proliferated myelin sheaths, the most of which having no neurofilaments and neurotubules. The other peculiar findings were the presence of microfilaments in Schwann cell cytoplasms, which were very similar to neurofilaments, and the presence of partial and abrupt disappearance of myelin sheaths. The severity of neuropathy was variable among nerve bundles, and a few nerve bundles looked normal on light microscopy. The above-mentioned lesions did not suggest the degeneration and/or regeneration of normally developed nerve fibers. We could not conclude the pathogenesis of this neuropathy, however, it was logical to consider that they reflected dysplastic myelination due to Schwann cell dysmaturity as well as the cerebral dysplasia.

Axons↗

PubMed1992

Differential effects of vecuronium on diaphragm and geniohyoid muscle in anaesthetized dogs.

We have examined the sensitivity of the geniohyoid, an upper airway dilating muscle, to vecuronium in 12 anaesthetized dogs undergoing mechanical ventilation of the lungs and compared it with that of the diaphragm. Dogs were allocated randomly to two groups: pentobarbitone alone (group 1, n = 7); pentobarbitone combined with 0.2 MAC (0.44%) of enflurane anaesthesia (group 2, n = 5). Supramaximal single twitch stimulations (0.1 Hz) were applied to the phrenic nerves in the upper thorax and the geniohyoid branches of the hypoglossal nerves at the neck. The evoked responses were assessed by the transdiaphragmatic pressure (Pdi) and the isometric force of the geniohyoid muscles (Tgh) until complete recovery of these variables after i.v. administration of vecuronium 0.02 mg kg-1. In both groups, the magnitude of the depression of twitch response was greater and time required to reach control amplitude was longer in the geniohyoid than the diaphragm. The depression of Tgh was significantly greater in group 2 than in group 1, whereas no change was observed in Pdi between the two groups. We conclude that the geniohyoid is more sensitive to vecuronium than the diaphragm and the differential effects of vecuronium are facilitated by a low concentration of enflurane.

Anesthesia, Inhalation↗

PubMed1992

Halothane does not depress contractile function of fresh or fatigued diaphragm in pentobarbitone-anaesthetized dogs.

We have studied the effect of halothane on diaphragmatic contractile function by measuring transdiaphragmatic pressure (Pdi) and electromyogram of the diaphragm (Edi) during various stimulation frequencies in 15 pentobarbitone-anaesthetized dogs undergoing mechanical ventilation. We have examined also the effect of halothane on the fatigued diaphragm by repeating the measurements 5, 10, 15, 30, 60 and 90 min after 30 min of tetanic stimulation applied to the phrenic nerves. Administration of 1-2 MAC of halothane did not affect Pdi at any given stimulation frequency. Changes in the depth of halothane anaesthesia (0, 1 and 2 MAC) did not alter the force-frequency relationship of the diaphragm during recovery from fatigue. Edi was unaffected by halothane, except for a small decline during 100-Hz stimulation with 2 MAC. In contrast with the changes in Pdi, Edi during recovery from fatigue was the same as that determined before fatigue. It is concluded that halothane, in clinical concentrations, did not depress the contractile function of fresh or fatigued diaphragm in vivo.

Anesthesia, Intravenous↗

PubMed1992

Permeability of the outer membrane of Moraxella catarrhalis for beta-lactam antibiotics.

The susceptibility of ten clinical isolates and a standard reference strain, ATCC25238, of Moraxella catarrhalis to 22 beta-lactam antibiotics was examined and compared with that of Escherichia coli strain B. All the strains of M. catarrhalis tested, especially the non beta-lactamase-producing strain ATCC25238, were more susceptible to a rang of structurally unrelated beta-lactam antibiotics, including small Mr carbapenems, than E. coli B. The permeability of the M. catarrhalis outer membrane to beta-lactam antibiotics was examined by the swelling technique with proteoliposomes reconstituted from outer membranes. The diffusion rate of beta-lactams through the liposome membrane was inversely related to their Mr, a relationship which might be expected for entry by diffusion through a porin.

Anti-Bacterial Agents↗

PubMed1992

Minimal model analyzing response of glycine receptors expressed in Xenopus oocyte: inhibition by a lipid hydroperoxide.

Glycine receptor (GlyR) was expressed in Xenopus oocytes by injecting rat brain mRNA. Glycine (Gly)-elicited responses in the oocyte were measured by the voltage-clamping method. The following measurements were made to establish the relationship between Gly concentration and the current: 1) Gly-induced membrane current before desensitization, 2) Gly-induced membrane current after desensitization equilibrium, 3) fraction of the active form of the receptor after desensitization equilibrium, 4) rate of recovery of the desensitized receptors upon removal of Gly. These results were analyzed on the basis of the minimal model proposed for nicotinic acetylcholine and gamma-aminobutyric acid A receptor. The equilibrium and rate constants of the model were evaluated for GlyR. The effects of procaine and 13-L-hydroperoxylinoleic acid (LOOH) on GlyR were examined electrophysiologically. LOOH noncompetitively inhibited the receptor with the inhibition constant of 27 microM, while 1 mM procaine, a local anesthetic, did not inhibit GlyR at all.

Animals↗

PubMed1992

Spontaneous infarction of an intraductal papilloma of the breast: cytological presentation on fine needle aspiration.

A relatively rare case of spontaneous infarction of an intraductal papilloma of the breast is presented which was considered to be suspicious for malignancy on fine needle aspiration (FNA) cytology. The aspirate revealed several groups of atypical cells featuring a high nuclear-cytoplasmic ratio, coarsely granular chromatin, and somewhat prominent nucleoli. There was abundant necrotic cellular debris in the background. These cellular features were considered evidence of ductal carcinoma of the breast. The correct diagnosis was made by open biopsy which revealed necrosis involving the breast due to infarction of an intraductal papilloma.

Adult↗

PubMed1992

In vitro and in vivo activities of DQ-2556 and its mode of action.

DQ-2556 is a recently developed cephalosporin with a broad spectrum of antibacterial activity against both gram-positive and gram-negative bacteria. Its in vitro activity was roughly comparable to those of cefuzonam and cefpirome and greater than those of ceftazidime, cefepime, and cefclidin against gram-positive bacteria. Against gram-negative bacteria, DQ-2556 showed almost the same activity as those shown by cefpirome and cefepime. The activity was largely unaffected by culture medium pH or the addition of human serum. The protective effect of DQ-2556 in experimental gram-positive pathogen and Escherichia coli infections in mice was greater than those of ceftazidime, cefuzonam, cefepime, and cefclidin and was similar to that of cefpirome. Against Pseudomonas aeruginosa and Acinetobacter calcoaceticus infections, DQ-2556 was more active than cefuzonam and had activity similar to or less than those of ceftazidime, cefpirome, cefepime, and cefclidin. When cells of E. coli were exposed to various concentrations of DQ-2556, filamentous cells were observed at concentrations of 0.0008 micrograms/ml and greater, spheroplasts started to form at 0.025 micrograms/ml, and subsequent cell lysis was observed. The affinity of DQ-2556 to PBP 3 of E. coli, which participates in septum formation, as suggested by morphological observation, was two times greater than that of ceftazidime. DQ-2556 also had high affinities for PBPs 1B and 1A of E. coli. These results suggest that DQ-2556 is worthy for subsequent clinical trials.

Animals↗

PubMed1992

In vitro antibacterial activity of Q-35, a new fluoroquinolone.

The in vitro activity of Q-35, an 8-methoxy fluoroquinolone, was compared with those of ofloxacin, ciprofloxacin, tosufloxacin, lomefloxacin, and sparfloxacin. The MICs of Q-35 for 90% of strains tested (MIC90s) of Staphylococcus aureus, methicillin-resistant S. aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, and Streptococcus pyogenes were 0.2, 6.25, 0.2, 0.39, and 0.39 micrograms/ml, respectively. The activity of Q-35 was 4- to 16-fold greater than those of ofloxacin, ciprofloxacin and lomefloxacin but equal to those of tosufloxacin and sparfloxacin against these organisms. For 82 ciprofloxacin-resistant staphylococci (MIC90 = 100 micrograms/ml), Q-35 was the most active of the new quinolones tested (MIC90 = 6.25 micrograms/ml). The MIC90s of Q-35 against Escherichia coli, Enterobacter aerogenes, and Pseudomonas aeruginosa were 0.2, 0.78, and 12.5 micrograms/ml, respectively, and Q-35 was 2- to 16-fold less active than the other quinolones tested. Q-35 showed potent bactericidal activity and inhibited the supercoiling activity of DNA gyrase of S. aureus, E. coli, and P. aeruginosa.

Anti-Infective Agents↗

PubMed1992

In vitro and in vivo antibacterial activities of E1077, a novel parenteral cephalosporin with a broad antibacterial spectrum.

E1077 is a new injectable cephalosporin with a broad spectrum of antibacterial activity against gram-positive and gram-negative bacteria, including staphylococci and Pseudomonas aeruginosa. The in vitro activities of E1077 against clinical isolates of methicillin-susceptible Staphylococcus aureus (MIC of E1077 for 90% of the strains tested [MIC90], 0.78 microgram/ml) and methicillin-resistant S. aureus (MIC90, 50 micrograms/ml) were similar to those of cefpirome and flomoxef. Against Enterococcus faecalis (MIC90, 6.25 micrograms/ml), E1077 was the most active of the drugs tested and four times more active than cefpirome. The MIC90S of E1077 for streptococci, Haemophilus influenzae, and Neisseria gonorrhoeae ranged from 0.05 to 0.78 microgram/ml; E1077 was similar in activity to cefpirome. E1077 inhibited 90% of most species of the family Enterobacteriaceae at concentrations of less than or equal to 1.56 micrograms/ml, with the exception of Serratia marcescens and Proteus vulgaris (12.5 micrograms/ml). The activity of E1077 against P. aeruginosa (MIC90, 6.25 micrograms/ml) was comparable to that of ceftazidime. In vivo activity was evaluated with systemic infections in mice. E1077 showed a protective effect against systemic infections by gram-positive or gram-negative bacteria, as reflected by its in vitro activity. The protective effects of E1077 were higher than those of cefpirome against S. aureus and P. aeruginosa infections and similar to those of cefpirome against other bacterial infections. Morphological studies using differential interference and phase-contrast microscopy showed that low concentrations of E1077 caused swelling of S. aureus and spheroplast and bulge formation in P. aeruginosa. In general, the antibacterial profile of E1077 is similar to that of cefpirome.

Animals↗

PubMed1992

Bactericidal activities of ofloxacin and its optically active isomer (DR-3355) on non-growing cells of Escherichia coli and Pseudomonas aeruginosa.

In this paper the bactericidal activities of ofloxacin and its optically active derivative, DR-3355, against non-growing cells of Escherichia coli and Pseudomonas aeruginosa are described. E. coli and P. aeruginosa were killed rapidly by ofloxacin and DR-3355. After treatment with these quinolones, the resting cells of E. coli and P. aeruginosa became plasmolyzed, with apparent cytoplasmic shrinkage without filamentation. Membrane-bound intracellular vacuoles and disruption of the cell envelope were also observed, resulting in extrusion of the cytoplasmic contents. These results indicate that non-growing cells of E. coli and P. aeruginosa were susceptible to ofloxacin and DR-3355, as were logarithmically growing cells.

Cell Cycle↗

PubMed1992

Respiratory responses to chest compression in human subjects.

To test the hypothesis that respiratory compensation for chest compression in the conscious state is different from that in the unconscious state, a range of chest compression was applied to eight conscious and eight anesthetized subjects. Chest compression was carried out by inflating a pneumatic cuff inserted under a chest corset and placed over the anterior chest wall for 5 min. Cuff inflation pressures were 25, 50, and 100 mm Hg: light, moderate, and heavy chest compression, respectively. In both conscious and anesthetized subjects, chest compression immediately caused a decrease in tidal volume (VT) and a concomitant increase in respiratory frequency (f). These changes stabilized within 2 min and remained nearly steady for the rest of the sustained chest compression. The decrease in VT was more prominent the greater the loads, and the change in f was in reverse proportion to the change in VT. In conscious subjects the increase in f was due to shortening of both inspiratory time (T1) and expiratory time (TE), whereas in anesthetized subjects the increase in f was due solely to shortening of TE. In conscious subjects, the values of minute ventilation (VI) and end-tidal PCO2 (PETCO2) during light and moderate chest compression were not different from the control values, whereas VI increased and PETCO2 decreased during heavy chest compression. In anesthetized subjects, the values of VI and PETCO2 were not different from the control values at any different magnitudes of chest compression.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Subcellular localization of xanthine oxidase in rat hepatocytes: high-resolution immunoelectron microscopic study combined with biochemical analysis.

Xanthine oxidase (XO), a molybdo-flavoprotein enzyme involved in purine degradation, was localized immunocytochemically in rat hepatocytes by high-resolution immunoelectron microscopy. XO was isolated from rat liver and a 150 KD polypeptide was purified. Antibodies were raised in rabbits. Small pieces of fresh liver were quickly frozen by contact with a copper block pre-cooled with liquid helium and were freeze-substituted with either 2.5% OsO4 or 0.2% glutaraldehyde in acetone. They were then warmed and embedded in Epon-Araldite or Araldite 6005. Resin sections were treated by indirect immunostaining using anti-rat liver XO antibody and protein A-gold. The labeling pattern was clearly over the cytosol and not on cell organelles. A few gold particles were found over the mitochondrial matrix, but not over the endoplasmic reticulum, Golgi apparatus, lysosomes, or peroxisomes, including their crystalloid core. These results are consistent with those of the biochemical assay of XO in this study. The significance of the occasional immunolabeling of the mitochondrial matrix remains obscure, since biochemical determinations in this study indicate no XO activity in the mitochondrial fraction.

Animals↗

PubMed1992

[The mechanism of the renal excretion of disopyramide in rats. I].

The mechanism involved in the renal excretion of disopyramide (DPM) is still incompletely understood. The purpose of this study was to examine the renal handling of DPM and the interactions between DPM and several organic anionic or cationic drugs related to the renal tubular secretion, using the renal clearance and renal cortical slices uptake techniques in rats. The clearance ratio of DPM was greater than that of glomerular filtration and this suggests the tubular secretion of DPM. The clearance ratio of DPM did not change after infusion of either anionic drugs (p-aminohippurate and probenecid) or a cationic drug (cimetidine). The results of time and concentration-dependent experiments using renal cortical slices demonstrated that DPM was accumulated against a concentration gradient by a saturable process. Inhibition of uptake by 2,4-dinitrophenol and cyanide indicated an energy dependence. DPM uptake was considerably inhibited by the cationic drugs, cimetidine and quinine, suggesting that DPM was transported by the cation transport mechanism. Probenecid, a competitor for the anion transport mechanism, moderately inhibited DPM uptake.

Animals↗

PubMed1992

[Recent trend and development of novel antimicrobial agents for MRSA infections].

Gram-positive organisms such as Staphylococcus aureus (including MRSA), coagulase-negative staphylococci, Enterococcus spp., and Streptococcus spp. have in recent years emerged as significant pathogens in hospitals and are now being isolated more frequently than gram-negative bacilli. These organisms are often multidrug resistant. Therefore, alternative agents with potent activity against gram-positive organisms are of considerable interest. In addition to the glycopeptide antibiotic vancomycin and the aminoglycoside antibiotic arbekacin, which can be used in MRSA infections, teicoplanin, RP 59500 and daptomycin are now under basic research in Japan. These antimicrobial agents are very active against gram-positive organisms, including MRSA and appear to be potent agents against infections due to gram-positive cocci, particularly MRSA.

Daptomycin↗