Search PubMed⌕ Search

Biomedical subjects

T Hirayama

Publications and source records attributed to T Hirayama.

At least 127 records · Page 7Linked to original sources
PubMed1997

Separate-hypothermia retrograde cerebral perfusion.

We have developed a technique of cerebral protection in which the blood for the retrograde cerebral perfusion from the superior vena cava cannula is cooled down to 10 degrees C, while the core temperature is maintained at moderate hypothermia. We performed graft replacement of the ascending and aortic arch in 2 patients with dissecting aneurysm using this method. This technique may provide excellent cerebral protection without coagulation disorder.

Aged↗
PubMed1997

Intraoperative monitoring of jugular bulb oxygen saturation in patients with moyamoya disease.

The jugular bulb oxygen saturation (SjO2) and end-tidal carbon dioxide (ETCO2) were monitored continuously during surgery in six cases of Moyamoya disease who had demonstrated multiple episodes of transient ischemic attacks (TIAs) and/or fluctuating neurological deficits preoperatively. The arterial carbon dioxide tension (PaCO2) levels were also measured repeatedly at predetermined interval. In two cases (group H), the ETCO2 was controlled at hypercapnic levels during surgery (45.5 +/- 1.5 mmHg) and the remaining four (group N) were operated on in a normocapnic state (39.0 +/- 2.0 mmHg). The group H patients demonstrated high levels of SjO2 ranging from 72 to 85%, indicative of excessive hyperemia. One of the group H patients demonstrated mild and transient motor weakness postoperatively. The group N patients demonstrated normal levels of SjO2 ranging from 66 to 78%. All the patients in both groups demonstrated fluctuations in SjO2 levels in clear positive correlation with spontaneous changes in PaCO2 levels. The present findings indicated that: (1) Global carbon dioxide reactivity of cerebral perfusion is well preserved in patients with Moyamoya disease; and (2) hypercapnia in these patients often causes excessive hyperemia. The occurrence of postoperative neurological deficits in association with such an excessive hyperemia suggests that hyperapnia during surgery is not always beneficial. Intraoperative monitoring of SjO2 is useful for maintaining cerebral perfusion within the optimum range.

Adolescent↗
PubMed1997

Pharmacological classification of central post-stroke pain: comparison with the results of chronic motor cortex stimulation therapy.

In an attempt to clarify the neurochemical background of central post-stroke pain and to undertake a pharmacological analysis, the basic pharmacological characteristics of this intractable pain syndrome were investigated by the morphine, thiamylal and ketamine tests. In addition, the correlation between the pharmacological characteristics and the effects of chronic motor cortex stimulation therapy was examined. The study employed 39 central post-stroke pain patients who had intractable hemibody pain associated with dysesthesias, and radiologically demonstrated lesions in the thalamic area (thalamic pain, n = 25) or suprathalamic area (suprathalamic pain, n = 14). The pharmacological evaluations showed that definite pain reduction occurred in eight of the 39 cases (20.5%) by the morphine test, in 22 of the 39 cases (56.4%) by the thiamylal test, and in 11 of 23 cases (47.8%) by the ketamine test. Based on these pharmacological assessments, there was no obvious difference between thalamic and suprathalamic pain. A comparison of the long-term follow-up results of chronic motor cortex stimulation therapy revealed that thiamylal and ketamine-sensitive and morphine-resistant cases displayed long-lasting pain reduction with chronic motor cortex stimulation therapy, whereas the remaining cases did not show good results. We conclude that pharmacological classification of central post-stroke pain by the morphine, thiamylal and ketamine tests could be useful for predicting the effects of chronic motor cortex stimulation therapy. It has recently been suggested that excitatory amino acids may be involved in the development of central post-stroke pain. However, the fact that only 23 of the present 39 cases (59.0%) of thalamic and suprathalamic pain were sensitive to the thiamylal or ketamine test reflects the complex pharmacological background and the difficulties associated with treating central post-stroke pain.

Adult↗
PubMed1997

AtPLC2, a gene encoding phosphoinositide-specific phospholipase C, is constitutively expressed in vegetative and floral tissues in Arabidopsis thaliana.

A cDNA encoding a phosphoinositide-specific phospholipase C (PI-PLC) from the higher plant Arabidopsis thaliana was cloned and characterized. The gene corresponding to this cDNA is designated AtPLC2. The overall structure of the predicted AtPLC2 protein is similar to those of plant PI-PLCs and mammalian delta-type PI-PLCs. Northern blot analysis revealed that AtPLC2 is expressed constitutively whereas AtPLC1S, another gene for PI-PLC of Arabidopsis, is induced by environmental stresses such as dehydration and salinity, indicating that the function of AtPLC2 is distinct from that of AtPLC1S. The AtPLC2 mRNA was detected in vegetative and floral tissues. We determined the positions of these two PI-PLCs genes on Arabidopsis chromosomes by RFLP mapping using P1 genomic clones.

Amino Acid Sequence↗
PubMed1997

Long term results using a modified King's method for cubital tunnel syndrome.

Forty-six elbows in 40 patients with cubital tunnel syndrome were evaluated after using a modified King's method. The average postoperative followup period was 79 months. The severity of cubital tunnel syndrome was graded before and after operation by the modified method of Stuffer et al which evaluated the amount of numbness, sensation, muscle strength, and muscle atrophy. The results were positively correlated with the preoperative severity of the disease and the ulnar nerve sulcus angle as measured in the axial view of the elbow. When the amount of the medial epicondylectomy was large, a good result was obtained, but the risk of medial collateral ligament insufficiency increased. Because the results of medial epicondylectomy are inconsistent with stability of the elbow, when doing a modified King's operation, careful repair of the medial collateral ligament is essential to minimize instability of the elbow.

Adult↗
PubMed1997

Nitrite reductase from Pseudomonas aeruginosa induces inflammatory cytokines in cultured respiratory cells.

Persistent infection with Pseudomonas aeruginosa increases interleukin-8 (IL-8) levels and causes dense neutrophil infiltrations in the airway of patients with chronic airway diseases. To investigate the role of P. aeruginosa infection in IL-8 production in the airway of these patients, we examined whether cell lysates of P. aeruginosa could cause IL-8 production from human bronchial epithelial cells. Diluted sonicated supernatants of P. aeruginosa (SSPA) with a mucoid or nonmucoid phenotype stimulated human bronchial epithelial (BET-1A) cells to produce IL-8. In this study, we have purified a 59-kDa heat-stable protein with IL-8-inducing activity from the SSPA by sequential ion-exchange chromatography. The N-terminal sequence of this purified protein completely matched a sequence at the N-terminal part of the mature protein of nitrite reductase from P. aeruginosa. In addition, immunoblotting with a polyclonal immunoglobulin G (IgG) against recombinant Pseudomonas nitrite reductase demonstrated a specific binding to the purified protein. Furthermore, the immunoprecipitates of the SSPA with a polyclonal IgG against recombinant nitrite reductase induced a twofold-higher IL-8 production in the BET-1A cell culture than did the immunoprecipitates of the SSPA with a control IgG. These lines of evidence confirmed that Pseudomonas nitrite reductase was responsible for IL-8 production in the BET-1A cells. The purified nitrite reductase induced maximal expression of IL-8 mRNA in the BET-1A cells at 1 to 3 h after stimulation, and the IL-8 mRNA expression declined by 8 h after stimulation. New protein translation was not required for nitrite reductase-mediated IL-8 mRNA expression in the BET-1A cells. Nitrite reductase stimulated the BET-1A cells, as well as human alveolar macrophages, pulmonary fibroblasts, and neutrophils, to produce IL-8. In contrast, nitrite reductase induced significant levels of tumor necrosis factor alpha and IL-1beta protein only in human alveolar macrophages. These data support the notion that nitrite reductase from P. aeruginosa induces the production of inflammatory cytokines by respiratory cells and may contribute to the pathogenesis of chronic airway diseases and persistent P. aeruginosa infection.

Bronchi↗
PubMed1997

Biological activities of novel zaragozic acids, the potent inhibitors of squalene synthase, produced by the fungus, Mollisia sp. SANK 10294.

Four novel zaragozic acids, F-10863A, B, C and D, were isolated from a culture broth of the fungus Mollisia sp. SANK 10294. F-10863 compounds contain a 4,6,7-trihydroxy-2,8-dioxyobicyclo-[3.2.1]octane-3,4,5-tricarboxyl ic acid core like previously reported zaragozic acids, but the structures of the side chains are different. Recently, it was found that F-10863A is identical to zaragozic acid D3, while the other three are novel compounds. F-10863 compounds are potent inhibitors of squalene synthase like previously reported zaragozic acids, and, furthermore, they exhibit serum cholesterol-lowering activity in vivo.

Animals↗
PubMed1997

[Reversible changes of cranial MRI in a girl with SLE].

The 11-year-old girl had hypertension and generalized tonic-clonic convulsions during the steroid pulse therapy. Her cranial T2-weighed MRI showed small areas of high signal intensity in the right occipital lobe. Her neurological findings were normal. After 2 months of steroid pulse therapy, multiple high signal intensities were demonstrated on T2-weighed MRI. After 5 months of the therapy, however, only a small T2-weighed MRI spot of high signal intensity in the white matter was observed, and the multiple lesions disappeared. On follow up, she did not show any neurological defects. It is postulated that not only steroid pulse therapy-induced hypertension but also SLE-induced angiopathy caused such flexible lesions. According to the literature, these lesions can be considered to be edema around small vessels. Such MRI findings have been reported in adult patients with SLE, but to our knowledge there have not been reports on children with SLE.

Brain↗
PubMed1997

[CABG performed for LMT orifice stenosis 15 years after AVR in a case of aortitis syndrome].

The case is a 54-year-old female at age 39 years, she underwent aortic valve replacement (AVR) for aortic valve regurgitation (AR) due to aortitis syndrome at a certain hospital. At the 15th year after AVR she was diagnosed with unstable angina due to LMT orifice stenosis and underwent CABG at this hospital. A distal side of anastomosis was performed on the LAD branch seg 6, an artificial vascular patch was placed for the proximal side of anastomosis to prevent inflammation of the aortic wall from spreading to the proximal side of anastomosis. On the postoperative cardiac catheter examination, the graft was found to be patent well. In the case of CABG complicated with aortitis syndrome, stenosis and obstruction of the proximal side of anastomosis long time after surgery pose a problem. However, the method so as to perform a proximal anastomosis by placing an artificial vascular patch on the aortic wall is considered to be one of the useful means which can avoid such a problem.

Angina, Unstable↗
PubMed1997

[A case of radical operation for right-sided infective endocarditis due to Pseudomonas aeruginosa concurrent with VSD in the elderly person].

The case is a 60-year-old male. He was seen at this department because of a slight fever of less than 37.5 degrees C from half a year earlier. Echocardiography revealed vegetations under the tricuspid valve and pulmonary valve, and on scintigraphy of the pulmonary blood flow he was diagnosed with multiple pulmonary infarction. Causative bacteria were not identified by blood culture on admission. As the intraoperative findings, vegetations were seen attached to the area from the septal cusp to the anterior cusp in the tricuspid valve. With the pulmonary valve, a part of the valvular cusp was perforated. After closing VSD with a patch, the vegetations attached to the valvular cusps were excised and the tricuspid valve was reconstructed. As for the pulmonary valve, valve replacement was performed because of the destructive degeneration of the valvular cusp. Pseudomonas aeruginosa was detected on culture of the tissue of the valvular cusp resected during operation. Post operative course was uneventful. The patient was discharged on the 21st postoperative day.

Bioprosthesis↗
PubMed1997

Characterization of melanosomes and melanogenesis in cells cultured from Ota's nevus.

Cells from dermis and epidermis of Ota's nevus lesions were cultured to obtain the pigment producing cells that are specific epidermal and dermal melanocytes of nevus Ota. The following media were used: Eagle's minimum essential medium, fortified or not fortified with cholera toxin and phorbol ester. Both epidermal melanocytes and dermal melanocytes grew in the Eagle's minimum essential medium fortified with cholera toxin and phorbol ester. The melanocytes were characterized by 14C-tyrosine uptake and by identification of melanosomes and status of melanogenesis in comparison with those reported in dysplastic nevi and melanomas, as well as those found in Ota's nevus tissue in situ. Eumelanosomes, pheomelanosomes and secondary lysosomal melanosomes appeared in epidermal melanocytes. Pheomelanosomes and melanolysosomes, or myelinosiderosomes appeared predominantly in the dermal melanocytes. These melanosomes seemed to be related to the peculiar skin color of nevus Ota. Some of the abnormal types of melanosomes were very similar to those found in dysplastic nevi and melanomas.

Dihydroxyphenylalanine↗
PubMed1996

A cdc5+ homolog of a higher plant, Arabidopsis thaliana.

We cloned and characterized a cDNA corresponding to a cdc5+ homolog of the higher plant, Arabidopsis thaliana. The cDNA, named AtCDC5 cDNA, encodes a polypeptide of 844 amino acid residues. The amino acid sequence of N-terminal one-fourth region of the predicted protein bears significant similarity to that of Schizosaccharomyces pombe Cdc5 and Myb-related proteins. Overexpression of the AtCDC5 cDNA in S. pombe cells is able to complement the growth defective phenotype of a cdc5 temperature-sensitive mutant. These results indicate that the AtCDC5 gene is a plant counterpart of S. pombe cdc5+. This is the first report of a cdc5(+)-like gene in a multicellular organism. We also demonstrated that a recombinant AtCDC5 protein possesses a sequence specific DNA binding activity (CTCAGCG) and the AtCDC5 gene is expressed extensively in shoot and root meristems. In addition, we cloned a PCR fragment corresponding to the DNA binding domain of human Cdc5-like protein. These results strongly suggest that Cdc5-like protein exists in all eukaryotes and may function in cell cycle regulation.

Amino Acid Sequence↗
PubMed1996

Genotoxicity in vivo of phenazine and aminophenazines assayed in the wing spot test and the DNA-repair test with Drosophila melanogaster.

The genotoxicity and DNA-damaging activity of 6 phenazine and aminophenazine derivatives were assayed in the wing spot and DNA-repair tests in Drosophila melanogaster. Phenazine (Pz), and all aminophenazines tested, namely, 1-aminophenazine (APz), 2-APz, 2,3-diaminophenazine (DAPz), 2,7-DAPz and 2,7-diamino-3,8-dimethylphenazine (DADMPz), exhibited mutagenicity significantly in the wing spot test. The activities in the wing spot test were ranked in a sequence DADMPz > (2,7-DAPz, 2,3-DAPz) > (2-APz, 1-APz, Pz). In the DNA-repair test, 2,3-DAPz, 2,7-DAPz, and DADMPz clearly showed DNA-damaging activity, but Pz, 1-APz and 2-APz were inactive. Based on these results, we predict that DADMPz, 2,3-DAPz and 2,7-DAPz are likely to be more carcinogenic than 2-APz, 1-APz or Pz.

Animals↗
PubMed1996

The significance of Ser1029 of the heat-stable enterotoxin receptor (STaR): relation of STa-mediated guanylyl cyclase activation and signaling by phorbol myristate acetate.

To characterize Ser1029 in STaR at a consensus sequence of phosphorylation site by PKC, two mutants of mS1029A with replacement of Ser1029 to Ala1029 and C delta 1029 lacking 22 amino acids including Ser1029 were prepared. Preincubation of the wild type-STaR (wt-STaR) transfectant with 1 microM PMA caused additional STa-mediated guanylyl cyclase (GC) activation compared to control, whereas the mS1029A- and C delta 1029-transfected cells did not show a similar enhanced GC activation by PMA. After metabolic labeling with [32P]phosphate, transfected cells with wt-STaR and mutants were incubated with 1 microM PMA. Subsequent 32P-radiolabeled proteins were immunoprecipitated using anti-STaR antibody, and analyzed by autoradiography after separation on SDS-PAGE. The immunoprecipitated wt-STaR but not mS1029A and C delta 1029 had a significant radioactivity. These results suggest that the effect of PMA on wt-STaR transfectants may be caused by phosphorylation of Ser1029. The C delta 1012 mutant, with further truncation (Gln1012-Phe1050) of the carboxy terminus, did not show STa-mediated GC activation. Based on these data, these 17 amino acids (Gln1012-Ala1028), essential for signaling of GC activation by STa, have an abundance of basic amino acids which might be functionally influenced by phosphorylation of Ser1029.

Amino Acid Sequence↗
PubMed1996

A gene encoding a mitogen-activated protein kinase kinase kinase is induced simultaneously with genes for a mitogen-activated protein kinase and an S6 ribosomal protein kinase by touch, cold, and water stress in Arabidopsis thaliana.

We describe here the cloning and characterization of a cDNA encoding a protein kinase that has high sequence homology to members of the mitogen-activated protein kinase (MAPK) kinase kinase (MAPKKK or MEKK) family; this cDNA is named cATMEKKI (Arabidopsis thaliana MAP kinase or ERK kinase kinase 1). The catalytic domain of the putative ATMEKK1 protein shows approximately 40% identity with the amino acid sequences of the catalytic domains of MAPKKKs (such as Byr2 from Schizosaccharomyces pombe, Ste11 from Saccharomyces cerevisiae, Bck1 from S. cerevisiae, MEKK from mouse, and NPK1 from tobacco). In yeast cells that overexpress ATMEKK1, the protein kinase replaces Ste11 in responding to mating pheromone. In this study, the expression of three protein kinases was examined by Northern blot analyses: ATMEKK1 (structurally related to MAPKKK), ATMPK3 (structurally related to MAPK), and ATPK19 (structurally related to ribosomal S6 kinase). The mRNA levels of these three protein kinases increased markedly and simultaneously in response to touch, cold, and salinity stress. These results suggest that MAP kinase cascades, which are thought to respond to a variety of extracellular signals, are regulated not only at the posttranslational level but also at the transcriptional level in plants and that MAP kinase cascades in plants may function in transducing signals in the presence of environmental stress.

Amino Acid Sequence↗