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H Inokuchi

Publications and source records attributed to H Inokuchi.

At least 91 records · Page 5Linked to original sources
PubMed1992

Pancreatic arteriovenous malformation with pancreatitis involving a pancreatico-venous fistula.

An arteriovenous malformation of the pancreas is a very rare disease, but its presentation is distinct and unique. In this report, we describe a patient who presented with this malformation which was localized in the tail of pancreas and demonstrated by abnormal angiography findings. The patient was a 60-year-old male with severe left hypochondralgia. Angiography revealed an increased blood volume in the tail of the pancreas with arteriovenous shunting. Secondary pancreatitis caused by the arteriovenous malformation was suspected by abnormal laboratory data, and confirmed by histology from the resected tail of the pancreas. This is a very rare report in which pancreatic arteriovenous malformation involving a pancreatico-venous fistula was confirmed by endoscopic retrograde cholangiopancreatography (ERCP).

Arteriovenous Fistula↗
PubMed1992

Fast inhibitory postsynaptic potentials and responses to inhibitory amino acids of sympathetic preganglionic neurons in the adult cat.

Intracellular recordings were obtained from sympathetic preganglionic neurons (SPNs) of the intermediolateral nucleus (IML) in slices of upper thoracic spinal cord of the anesthetized cat. A total of 44 neurons was studied. Single shock stimulation of an area of white matter dorsolateral to the IML, close to the recording electrode (< 0.5 mm), evoked fast IPSPs with rise time of 3.8 ms and 1/2 decay time of 14.7 ms (n = 12). In 17 other cells only fast EPSPs were recorded but, after suppression of the EPSPs by the excitatory amino acid receptor antagonists CNQX (20 microM) and APV (100-250 microM), fast IPSPs were unmasked. The IPSP reversed polarity at -63 mV (-67 mV in the presence of CNQX and APV). The reversal potential shifted to a less negative value when the extracellular chloride concentration was reduced. The IPSP was reversibly abolished by the GABAA receptor antagonist bicuculline in 32% of the cells, by the glycine receptor antagonist strychnine in 47% of the cells and by the combination of the two in 21% of the cells. The IPSP was abolished by TTX (0.5 microM), had constant latency and showed no failures during high frequency stimulation. The IPSP presumably resulted from the excitation of inhibitory axons and/or inhibitory neuron somata with monosynaptic connections to the SPN. Glycine and GABA (1-3 mM) produced hyperpolarization associated with decreased membrane resistance. Sixty-nine percent of cells responded to both agonists, 19% to glycine only and 12% to GABA only. The GABAB agonist baclofen (5 microM) had no effect.(ABSTRACT TRUNCATED AT 250 WORDS)

2-Amino-5-phosphonovalerate↗
PubMed1992

Fast excitatory postsynaptic potentials and the responses to excitant amino acids of sympathetic preganglionic neurons in the slice of the cat spinal cord.

The properties of the excitatory postsynaptic potential evoked by focal stimulation and of the responses to excitatory amino acids were examined by intracellular recording from sympathetic preganglionic neurons in upper thoracic spinal cord slices of the adult cat. Single stimuli to the region dorsal to the intermedio-lateral nucleus evoked short-latency, presumably monosynaptic, excitatory postsynaptic potentials. The reversal potential of this response was -2.2 mV and became more negative when external Na+ or K+ concentration was decreased. The excitatory postsynaptic potential was depressed by the non-selective excitatory amino acid receptor antagonist cis-2,3-piperidine dicarboxylic acid and enhanced by a glutamate uptake inhibitor. The non-N-methyl-D-aspartate receptor antagonist 6-cyano-7-nitroquinoxaline-2.3-dione abolished the excitatory postsynaptic potential in 72% of neurons. In the remaining neurons, this antagonist only depressed the potential and unmasked a slower component which was abolished by the N-methyl-D-aspartate receptor antagonist D,L-2-amino-5-phosphonovaleric acid. In the presence of tetrodotoxin all neurons tested were depolarized by glutamate or aspartate, as well as by the selective agonists quisqualate, alpha-amino-3-hydroxy-5-methylisoxazole propionic acid, kainate and N-methyl-D-aspartate. The glutamate-evoked depolarization reversed at a membrane potential of -2.0 mV and at a more negative value when external Na+ or K+ concentration was decreased. The response to alpha-amino-3-hydroxy-5-methylisoxazole propionic acid was abolished by 6-cyano-7-nitroquinoxaline-2,3-dione in all neurons tested and that to kainate in only one-third of the cells. In the remainder the response to kainate was only slightly depressed by this antagonist. The responses to glutamate and aspartate were only slightly depressed by the combined action of the various amino acid receptor antagonists used. The responses to N-methyl-D-aspartate were abolished by D,L-2-amino-5-phosphonovaleric acid. The punched-out region of the intermedio-lateral nucleus, maintained in vitro, released glutamate and aspartate in the absence of stimulation. Field stimulation (20 Hz) enhanced release by between 40 and 100%. The increase was prevented by superfusion with calcium-free Krebs. It is concluded that excitatory amino acids, acting on both N-methyl-D-aspartate and non-N-methyl-D-aspartate receptors, but mainly on the latter, are likely mediators of the monosynaptic excitatory postsynaptic potential evoked in sympathetic preganglionic neurons by the stimulated region. The efflux data suggest that glutamate and aspartate are among the mediators.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1992

Isolation and characterization of a light-sensitive mutant of Escherichia coli K-12 with a mutation in a gene that is required for the biosynthesis of ubiquinone.

Cells with a novel mutation that is lethal when the cells are exposed to visible light were isolated from Escherichia coli K-12. The mutation was mapped at 63 min on the linkage map of the E. coli chromosome, and the gene, designated visB, was cloned and sequenced. From its map position and the evidence that the gene product VisB exhibits homology with flavin monooxygenase of Pseudomonas fluorescens, the visB gene was deduced to be identical to the ubiH gene, which is a gene required for the biosynthesis of ubiquinone and is thought to be similar to the gene for flavin monooxygenase. The photosensitive phenotype appears to be due to the accumulation of the substrate for the reaction catalyzed by the visB (ubiH) gene product because other mutations that block earlier steps in the biosynthesis of ubiquinone can reverse the photosensitivity. The accumulated intermediates may produce active species of oxygen in the mutant bacteria upon illumination by visible light, and these active oxygen species may cause the death of the cells by a mechanism similar to that associated with mutations in visA (hemH).

Amino Acid Sequence↗
PubMed1992

Adrenergic receptors (alpha 1 and alpha 2) modulate different potassium conductances in sympathetic preganglionic neurons.

Intracellular recordings were made from 168 sympathetic preganglionic neurons in the slice of the second or third thoracic spinal-cord segment of the adult cat to study the actions of noradrenaline on these neurons. Noradrenaline, applied by superfusion (0.5-50 microM), produced membrane depolarization in 73 neurons and membrane hyperpolarization in 39 neurons. In 26 neurons noradrenaline produced a biphasic response (depolarization-hyperpolarization or vice versa). The depolarization was blocked by prazosin, while the hyperpolarization was blocked by yohimbine. The noradrenaline-induced depolarization was associated with an increase in neuron input resistance, while the noradrenaline-induced hyperpolarization was associated with a decrease in neuron input resistance. Both responses decreased in amplitude with membrane hyperpolarization and were nullified at around the potassium equilibrium potential EK. The null potential of both responses became more and less negative with a decrease and an increase, respectively, in the extracellular potassium concentration. When the membrane potential was made more negative than EK, the noradrenaline-induced hyperpolarization reversed to depolarization in all cases, whereas in only 4 of 12 cases did the noradrenaline-induced depolarization reverse to hyperpolarization. These data suggest that the noradrenaline-induced depolarization is a result of a decrease, while the noradrenaline-induced hyperpolarization is a result of an increase in K+ conductance. Cobalt (2 mM), low calcium--high magnesium, and intracellular EGTA markedly reduced or abolished the noradrenaline-induced depolarization but had no significant effect on the noradrenaline-induced hyperpolarization. Barium (2 mM) depressed both responses. Tetraethylammonium (10-30 mM), 4-aminopyridine (3 mM), and cesium (2 mM) had no effect on either response.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Photosensitivity of a protoporphyrin-accumulating, light-sensitive mutant (visA) of Escherichia coli K-12.

Mutations in the visA gene of Escherichia coli cause the mutant bacteria to die upon illumination with visible light. We confirmed genetically that the visA gene is a structural gene for ferrochelatase (protoheme ferro-lyase, EC 4.99.1.1). Since other mutations in the genes involved in the biosynthesis of heme can cure the photosensitivity, the light-induced cell death appears to be brought about by the accumulation of protoporphyrin IX, one of the substrates of ferrochelatase. When cells are illuminated with visible light, protoporphyrin IX seems to produce an active species of oxygen (probably 1O2) that is harmful to the cells. This defect is the same as that associated with the human disease protoporphyria.

Anaerobiosis↗
PubMed1991

Isolation and characterization of visible light-sensitive mutants of Escherichia coli K12.

Six mutants of Escherichia coli K12 that are sensitive to visible light have been isolated. Five of them, including an amber mutant, are defective in a gene that maps near 11 minutes on the linkage map of the chromosome, and this gene has been designated visA. The sixth mutant, which was isolated from bacteria that carried the visA+/visA+ diploid allele, is defective in a gene that maps near 63 minutes on the linkage map, which has been designated visB. These mutant strains of bacteria are killed by illumination with visible light. The effective wavelength of the light is around 460 nm. The nucleotide sequence of the visA gene was determined. As a result of a search for homologous products, we found that visA may be identical to hemH, the structural gene for ferrochelatase which catalyzes a final step in the biosynthesis of heme. A possible mechanism for the killing of the visA mutant bacteria is discussed.

Amino Acid Sequence↗
PubMed1991

Precise mapping of the rnpB gene encoding the RNA component of RNase P in Escherichia coli K-12.

In Kohara's library derived from Escherichia coli K-12 W3110 (Y. Kohara, K. Akiyama, and K. Isono, Cell 50:495-508, 1987), multiple copies of chromosomal sequence are found at 68 and at 64 to 65 min (M. Umeda and E. Ohtsubo, J. Mol. Biol. 213:229-237, 1990). We have determined that the rnpB gene (previously mapped at 70 min [B. J. Bachmann, Microbiol. Rev. 54:130-197, 1990]) is located within these segments of repeated sequences as five separate copies, together with tdcA, B, C, and R (mapped at 68 min [Bachmann, 1990]) and six unidentified open reading frames. Since close linkage of rnpB and tdc is found in various strains of E. coli K-12, the rnpB gene should be mapped at 68 min rather than 70 min.

Base Sequence↗
PubMed1991

Synaptic responses of guinea pig and rat central amygdala neurons in vitro.

1. To investigate postsynaptic potentials (PSPs), we made intracellular recordings from neurons of the amygdaloid central nucleus in slices from the guinea pig and rat brains maintained in vitro. The results from guinea pigs and rats were very similar. 2. In the presence of bicuculline (20 microM), focal electrical stimulation of the amygdaloid basal nucleus with low intensities elicited short-latency excitatory PSPs (EPSPs) followed by long-latency EPSPs. The short-latency EPSP was selectively blocked by 6-cyano-7-nitroquinoxaline-2,3-dion (CNQX; 10-20 microM). The long-latency EPSP was preferentially abolished by D,L-2-amino-5-phosphonovaleric acid (D,L-APV; 40 microM) and was augmented by removal of extracellular Mg2+. The compound EPSP reversed at -4 mV, which was close to -1 mV, the reversal potential for pressure-ejected glutamate (Glu). 3. When the intensity of the focal stimulation was increased in the presence of bicuculline (20 microM), CNQX (20 microM), and D,L-APV (50 microM), a second EPSP with a short latency and a prolonged duration could be evoked in approximately 65% of the neurons. The EPSPs were reversibly blocked by d-tubocurarine (50 microM) or hexamethonium (200 microM) but were unaffected by atropine (1 microM) or a 5-hydroxytryptamine type 3 receptor antagonist, ICS-205930 (5-10 microM). In these neurons, acetylcholine (ACh; 1-3 mM) caused a depolarization, associated with a decreased input resistance. 4. In the presence of CNQX (20 microM) and D,L-APV (50 microM), single focal stimulation of the dorsolateral subdivision in the central nucleus with low intensities elicited a depolarizing inhibitory PSP (IPSP). The IPSP was reversibly abolished by bicuculline (20-40 microM). The reversal potential (-63 mV) for the IPSP was similar to the reversal potential (-61 mV) for the response to gamma-aminobutyric acid (GABA) applied by pressure ejection. 5. In the presence of bicuculline (20-40 microM) and CNQX (20 microM), a repetitive focal stimulus with high intensities delivered to the dorsolateral subdivision produced a hyperpolarizing PSP followed by a slow depolarization in most neurons. Of putative inhibitory amino acid transmitters, glycine (Gly; 3 mM) produced only a hyperpolarization, associated with a decrease in input resistance. Strychnine (1-2 microM) reversibly blocked both the Gly hyperpolarization and the synaptically evoked hyperpolarization. The reversal potential of -81 mV for the hyperpolarizing PSP was close to -82 mV for the Gly hyperpolarization. The reversal potential for the Gly response was shifted to less negative values by increasing the external K+ concentration or decreasing the extracellular Cl- concentration.(ABSTRACT TRUNCATED AT 400 WORDS)

2-Amino-5-phosphonovalerate↗
PubMed1991

[Surgical infection and its backgrounds].

The backgrounds of surgical infection of esophageal cancer patients are studied for host factors (relation of nutrition and immune response) and parasite factors surgical parts which are easily contaminated, the differences of serum concentration with 3 methods of antibiotics administration, and the relations about the bacteria in mouth and upper esophagus in operation and bacteria which were found in the respiratory system after operation). The results are as follows. The preoperative nutritional support was effective to rapid recovery of cytological immune functions. But in the post-operative infected cases, immunological recovery delayed and they nutritionally needed BCAA, glutamine, and essential fatty acids. For the study of parasite factors, surgical wounds (neck, chest wall, abdominal wall) were more easily contaminated than other parts except digestive tract. Continuous administration of antibiotics, 1g/hr x 4 was most excessive in three methods. The bacteria in the mouth and upper esophagus in operation and those in airway after operation, were not correlated. Furthermore, antibiotics-resistant bacteria which were Pseudomonas, MRSA were found in the airway. These results indicate that nutritional support is important for the host defense system and antibiotics should be administered considering each operative process. And about the postoperative respiratory infection, protection of hospital infection is important.

Bacterial Infections↗
PubMed1990

Importance of the G27-A43 mismatch at the anticodon stem of Escherichia coli tRNA(Thr2).

The tRNA(Thr2) isoacceptor of E. coli has a G-A mismatch at positions 27-43. When the anticodon of this tRNA was converted to an amber anticodon (CUA), this tRNA showed suppressor activity in E. coli. Moreover, introduction of the base pair (G-C or U-A) at positions 27-43 of this suppressor tRNA reduced its suppressor activity. These results indicate that the G27-A43 mismatch is necessary for full function of tRNA(Thr2).

Anticodon↗