Search PubMed⌕ Search

Biomedical subjects

H Ashida

Publications and source records attributed to H Ashida.

At least 91 records · Page 5Linked to original sources
PubMed1996

US-guided drainage of deep neck space abscess.

Infection of oropharyngeal or upper airway origin may extend to potential spaces formed by fascial planes of the cervical area. These space infections have been greatly reduced by modern antibiotic therapy. However, serious complications continue to occur. An 18-year-old man who presented with neck mass was admitted and treated. He underwent ultrasonically guided drainage procedure using Percuflex drainage catheter within 6 h of his arrival. He was discharged from the hospital 10 days later. Although it is still thought that early open surgical drainage is the most appropriate method for treatment of deep cervical abscess, early treatment with a drainage catheter such as Percuflex may replace surgery. Life threatening complications can thus be avoided with good cosmetic results and rapid recovery.

Abscess↗
PubMed1995

Protein kinase C inhibitors affect induction of long-lasting potentiation in the somatosensory cortex.

The effects of protein kinase C (PKC) inhibitors on the induction of long lasting potentiation (LLP) of field potentials in the feline somatosensory cortex were studied. LLP was induced by high frequency stimulation (HFS, 200 Hz) of the ventral posterolateral thalamic nucleus. First, the effects of a protein kinase inhibitor, H-7, and a specific PKC catalytic domain inhibitor, chelerythrine, on the LLP in the secondary somatosensory cortex (SII) were investigated. Intracortical microinjections of H-7 and chelerythrine at 30 min before HFS inhibited induction of LLP in SII, while an injection of chelerythrine at 60 min after LLP induction had no effect on the potentiation. Second, changes in PKC activity in the presence of calcium and phosphatidylserine were investigated in SII after induction of LLP. Triton-soluble membrane fractional PKC activity had increased to 350% of the control value with low frequency test stimulation (0.1 Hz) by five min after HFS. In contrast, PKC activities of cytosolic fractions decreased to 25.6% of the control value. At 60 min after HFS, the PKC activity level returned to the control value, despite persistent potentiation in all cases. PKC activation is considered to be one of the factors required for induction of LLP but not for maintenance in SII.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1995

Motion aftereffect with flickering test stimuli depends on adapting velocity.

Temporal tuning property of motion aftereffect (MAE) with flickering test stimuli (flicker MAE) was examined. Using sinusoidal gratings of several spatial frequencies (SF), MAE strength was measured for various adapting temporal frequencies (TF). Unlike the traditional MAE with static test field, the results indicated that flicker MAE did not depend on TF. Rather, when plotted as a function of velocity, the peaks had approximately the same adapting velocity of 5-8 deg/sec for all SF conditions tested, suggesting velocity dependence. This is further support of the idea that the two kinds of MAE are of different origin and suggests a higher origin of flicker MAE, perhaps in the area MT or MST.

Adaptation, Ocular↗
PubMed1995

Cloning and sequence analysis of genes for cyclophilin from Arabidopsis thaliana.

Two genomic DNA clones encoding cyclophilin (CyP) from Arabidopsis thaliana were isolated. The deduced protein products of these genes appeared to be cytosol-localized isoforms given the absence of a specific presequence for targeting to cellular compartments. Thus, multiple CyPs may exist and function in the cytosol of Arabidopsis thaliana.

Amino Acid Isomerases↗
PubMed1995

Structure and replication of cryptic plasmids, pMA1 and pMA2, from a unicellular cyanobacterium, Microcystis aeruginosa.

The 4993-bp cryptic plasmid, pMA2, from a cyanobacterium, Microcystis aeruginosa f. aeruginosa Kützing, originally derived from Kasumigaura lake, was completely sequenced and analyzed. Plasmid pMA2 had a unique sequence motif CTTGATT, which was proposed to be a nicking site on the smaller plasmid pMA1 (2287-bp) by the presence of single-stranded DNA susceptible to S1 nuclease. We had detected the occurrence of the single-stranded pMA1 in the living M. aeruginosa cells. This was also the case of pMA2. Thus, we suggest that both plasmids, pMA1 and pMA2, replicate through the rolling circle mechanism. By computer analysis of the pMA2 sequence, two open reading frames were found: one had a predicted molecular size of 30,440 Da and the other on a complementary one had a predicted molecular size of 10,852 Da. No rep protein was detected. Replication mechanisms of the plasmids are discussed.

Amino Acid Sequence↗
PubMed1995

Formation of lyso-glycosphingolipids by Streptomyces sp.

The actinomycete strain Streptomyces sp. H37 produces a novel glycosphingolipid-degrading enzyme. This strain was capable of converting ganglioside GM1 to lyso-GM1. After cultivation for 5 days in medium containing GM1, peptone, and detergent, GM1 was found to be almost completely converted to lyso-GM1. The product was purified on a DEAE-Sephadex A-25 column and thin layer chromatographies. The purified lyso-GM1 was hydrolyzed by endoglycoceramidase, and the released oligosaccharide moiety was identified as that of GM1 by HPLC using the pyridylaminoderivative method. The counterpart sphingosine moiety was confirmed with TLC. Moreover, the structure of lyso-GM1 was ascertained by 1H-NMR analysis. The maximum formation of lyso-GM1 was found in 50 mM potassium phosphate buffer (pH 7.5) containing 0.1% glycodeoxycholate. Various lyso-glycoshingolipids, including those of ganglio-, neolacto-, and globo-types, were formed from their parent glycosphingolipids using this strain.

Chromatography, High Pressure Liquid↗
PubMed1994

Complete interocular transfer of motion aftereffect with flickering test.

It has been suggested that motion aftereffect with static test patterns (static MAE) reflects activities at a lower level system that dominantly processes first-order motion, while MAE with a directionally ambiguous test (flicker MAE) reveals a higher level system where second-order motion signals as well as first-order signals are available. To test this hypothesis, we examined interocular transfer of static and flicker MAE. Flicker MAE should transfer more efficiently than static MAE if it occurs at a higher level system. In the first experiment, the adaptation stimulus was a drifting luminance grating (first-order motion), or a drifting grating defined by flicker or texture difference (second-order motion). The test stimulus was a luminance grating, either static or counterphasing. The results indicated that static MAE, which was induced only by first-order motion, transferred partially, as has been reported in previous studies, but the transfer of flicker MAE was nearly perfect with either first- or second-order adaptation stimuli. The second experiment with varied adaptation contrast indicated that this complete transfer was not due to a ceiling effect. These results supported the hypothesis that the underlying mechanism for flicker MAE is located at a level higher than the mechanism for static MAE.

Adaptation, Physiological↗
PubMed1994

Difference of spatial frequency selectivity between static and flicker motion aftereffects.

The strength of motion aftereffect (MAE) was measured with the use of sinusoidal gratings of several spatial frequencies, to examine the spatial frequency selectivity of two types of MAE. With ordinary static grating as a test stimulus, to measure 'static MAE', the maximum aftereffect for each adapting spatial frequency was obtained at the testing stimuli of the same spatial frequency, showing spatial frequency selectivity. However, in the case when the sinusoidally flickering grating was used as a test stimulus, to measure 'flicker MAE', no spatial frequency selectivity was observed. The two types of MAE were considered to be based on different mechanisms. Static MAE is thought to depend on the spatiotemporal channel mechanism in the early processing stages, whereas flicker MAE might reflect higher-level processes which might occur at the extrastriate regions.

Fixation, Ocular↗
PubMed1994

Reproducibility of magnetic resonance spectroscopy in patients undergoing dialysis and evaluation of the therapeutic response of tumors.

RATIONALE AND OBJECTIVES: The reproducibility of repeated magnetic resonance (MR) spectroscopy was studied in patients undergoing dialysis and treatment of a variety of malignant tumors. METHODS: Localized MR spectra were obtained using a 1.5-T system by image-selected in vivo spectroscopy. Total metabolite signal was integrated between phosphomonoester and beta-adenosine triphosphate resonance. We termed this measurement AREA. RESULTS: Intrapatient variability was evaluated on repeated thigh muscle spectroscopy for 10 patients. Sequential spectra of 10 malignant tumors of the extremities were analyzed and compared with the histology of surgical specimens in seven patients. Intrapatient variability in AREA was calculated as 14.0%. The extent of necrosis and AREA ratio (definition: AREA post-therapy/AREA pretherapy) were as follows; 6.1% in > 90% necrosis, 43% in 50% to 90% necrosis, and 79% in < 50% necrosis. CONCLUSIONS: Localized MR spectra are fairly reproducible and may relate to treatment efficacy.

Adolescent↗
PubMed1994

Replication of filamentous cyanobacterial plasmids, pPF1 from Phormidium foveolarum and pPB1 from Plectonema boryanum.

Single-stranded plasmid DNA of pPF1 from Phormidium foveolarum that was specifically degraded by S1 nuclease was detected by Southern hybridization. This is also the case of the homologous plasmid pPB1 from Plectonema boryanum. These observations suggest that such small cryptic plasmids as pPF1 and pPB1, both from Gram-negative and filamentous cyanobacteria, replicate by a rolling circle mechanism in their living cells.

Base Sequence↗
PubMed1994

The effect of splenomegaly on splanchnic hemodynamics in nonalcoholic cirrhosis after distal splenorenal shunt and splenopancreatic disconnection.

We investigated the effect of splenomegaly on portal hemodynamics during and after distal splenorenal shunt with splenopancreatic disconnection in 27 patients with nonalcoholic cirrhosis (13 with and 14 without splenic enlargement). Data were obtained by Doppler flowmetry, electromagnetic flowmetry and computed tomographical scanning. The splenomegaly group had a significantly higher preoperative splenic and portal blood flow than the nonsplenomegaly group. In both groups, postoperative portal venous pressure did not fall; portal blood flow significantly decreased while splenic volume was reduced, despite the lack of significant changes in splenic venous blood flow. There was a greater reduction of portal blood flow with previous splenomegaly than with normal-sized spleens, and this was not related to the degree of reduction in liver volume. In the splenomegaly group, the increase of splenic blood flow was only present during the early postoperative period. In conclusion, distal splenorenal shunt with splenopancreatic disconnection influenced portal hemodynamics differently in nonalcoholic cirrhotic patients with and without splenomegaly.

Female↗
PubMed1993

Long-lasting potentiation of field potentials in primary and secondary somatosensory cortex.

Effects of tetanic bursts (200 Hz, 10 pulses) on field potentials elicited by ventral posterolateral thalamic nucleus (VPL) stimulation were investigated in the feline somatosensory cortex. In the first experiments, field potentials elicited by VPL stimulation (test pulse) were simultaneously recorded in the primary (SI) and the secondary (SII) somatosensory cortex in six animals. Potentiation of field potentials recorded in SII was induced by tetanic stimulation of VPL in all six animals, whereas the same tetanic bursts failed to produce significant changes in SI in four of the six animals. The results suggest that plastic changes in somatosensory processing take place in SII rather than SI. In subsequent experiments, features of the potentiation observed in SII were examined in 20 animals. The field potentials were simultaneously recorded at 16 points placed vertically at 150-microns intervals from the cortical surface. The potentiation of field potentials (to 110-170% of control values) observed at depths between 600 and 1350 microns lasted more than 90 min after tetanic stimulation. Poststimulus histograms of multiple-unit activities revealed a long-lasting increase in the number of unit discharges evoked by VPL stimulation. This change in the number of activated cells is regarded as a cause of potentiation of SII field potentials. In the last session, the effects of N-methyl-D-aspartate (NMDA) receptor antagonists on the potentiation of SII field potentials were investigated. Cortical intraventricular injection of D-2-amino-5-phosphonovalerate (APV) and DL-2-amino-7-phosphonoheptanoic acid (APH) prevented induction of the potentiation in SII. NMDA receptor activation participates in forming this SII potentiation.

2-Amino-5-phosphonovalerate↗
PubMed1993

Transglycosylation activity of endoglycoceramidase from Corynebacterium sp.

Endoglycoceramidase (EGCase) catalyzes the hydrolysis of the linkage between oligosaccharides and ceramides of various glycosphingolipids (GSLs). We found that the EGCase from Corynebacterium sp. had transglycosylation activity. Digesting GSLs with the enzyme in the presence of a suitable acceptor gave a mixture of hydrolytic and transglycosylic products. When GM1 was used as the substrate (donor), 1-hexanol was found to be the best acceptor of transglycosylation activity. Hexyl-II 3NeuAcGgOse4 produced was confirmed by fast-atom bombardment-mass spectrometry analysis and exoglycosidase digestion. The enzyme also transferred oligosaccharides of various GSLs to 1-hexanol.

Corynebacterium↗
PubMed1993

A comparison of the metabolic changes after the distal splenocaval and portacaval shunts.

The distal splenorenal shunt (DSRS) is the recommended procedure for selective variceal decompression, but its use may be limited in patients who have undergone left nephrectomy, those with an anatomically aberrant relationship between the splenic and left renal veins, and those whose preoperative angiographic findings suggest a risk of developing postoperative renal vein hypertension. For these clinical situations, the selective distal splenocaval shunt (DSCS) is a useful alternative to the DSRS. However, the metabolic consequences of the DSCS have not yet been studied in detail and therefore, using a canine model, the metabolic changes following the DSCS and the portacaval shunt (Eck) were compared. The metabolic changes observed following the Eck were hyperammonia and amino acid imbalance, while those following the DSCS were similar to those of the control dogs. In terms of the hepatic adenosine triphosphate level, which reflects hepatic mitochondrial function, the DSCS dogs were also similar to the control dogs. These data suggest that there was no metabolic disadvantage of the DSCS compared to the control.

Adenosine Triphosphate↗
PubMed1993

Structural organization of a cryptic plasmid, pMA1, from Microcystis aeruginosa f. aeruginosa Kützing.

The 2287-bp cryptic plasmid, pMA1, from Microcystis aeruginosa f. aeruginosa Kützing, a unicellular cyanobacterium originally derived from Kasumigaura lake, was completely sequenced and analyzed. The predicted amino acid sequence (253 residues) of an open reading frame had identities of 47%, 48%, and 53% with replication-associated proteins of Bacillus amyloliquefaciens's plasmid, pFTB14, B. subtilis BAA1's pBAA1, and B. coagulans's pBC1, respectively, when conservative amino acid substitutions were included. Such high-level identities were also shown with rep proteins and ori regions in a group of Gram-positive bacterial plasmids such as Lactococci and Staphylococci that are known to replicate via single-stranded intermediates. The pMA1 does hybridize with a plasmid, pUS1-3, derived from another unicellular cyanobacterium, Synechocystis sp. PCC 6803. Novel features of pMA1 are discussed.

Amino Acid Sequence↗
PubMed1993

Clinical staging and gadolinium-DTPA enhanced images of the wrist in rheumatoid arthritis.

The usefulness of gadolinium (Gd)-DTPA enhanced magnetic resonance imaging (MRI) of the wrist joint for predicting articular destruction was investigated in 49 patients with rheumatoid arthritis (RA). On T1 weighted images with Gd-DTPA enhancement, the synovium showed a localized or diffuse pattern of enhancement. Many patients classed as stage II or higher by plain radiography had diffuse enhancement on MRI, while all except one stage I patient had relatively confined localized enhancement. Our study showed that MRI of the carpus could detect soft tissue changes in patients with RA earlier than anything revealed by radiography, and suggested that contrast MRI may be useful for predicting articular destruction.

Arthritis, Rheumatoid↗
PubMed1993

Analysis of hepatic encephalopathy after distal splenorenal shunt--PTP image and pancreatic hormone kinetics.

The Warren-Zeppa selective distal spleno-renal shunt is aimed at decompressing esophageal varices while at the same time ligating left gastric, gastroepiploic and umbilical veins. But in the long term follow-up loss of shunt selectivity was observed in a number of cases (7/76), with hepatic encephalopathy resulting in 9.3%. In this study, we carried out percutaneous transhepatic portography and investigated pancreatic hormone kinetics in portal blood after arginine load, mainly in cases of hepatic encephalopathy after distal splenorenal shunt compared with non-encephalopathy cases of LC + Varix. These data suggested that as a cause of encephalopathy after distal splenorenal shunt, (1) a marked decrease in portal blood flow due to portal systemic shunt via the pancreatic vein was considered from PTP image, (2) a marked decrease in I/G ratio was considered from pancreatic hormone kinetics in portal blood.

Blood Glucose↗