Biomedical subjects

Y Ichikawa

Publications and source records attributed to Y Ichikawa.

At least 469 records · Page 26Linked to original sources

PubMed1992

[Clinical experience of continuous retrograde cerebral perfusion for assisted circulation during the surgical treatment of acute dissection of aorta: Stanford A type].

Surgical treatment of the dissection involving the ascending aorta or aortic arch represents one of the most complicated technical challenges. Recently continuous retrograde cerebral perfusion (CRCP) is sometimes applied in order to avoid cerebral complications. We compared two surgical groups, one of which was performed graft-replacement of ascending aorta using CRCP and another was utilized normograde cerebral circulation, about the technique of operation, total extracorporeal circulation (ECC) time, aortic clamp time, separate ECC time, total bleeding volume, and urination during operation. In the group using CRCP, separate ECC time was 53 min (mean), and intraoperative bleeding volume was only 1,170 ml. Good urination was obtained during operation. Postoperative courses were uneventful, and consciousness was smoothly and soon recovered. The new method of separate ECC has some advantages over the previously described methods, particularly for avoidance of cerebral complications. As it is not necessary to require dissecting, taping, and clamping of cephalic branches, operative procedure will be very simplified, easier and safer, leading to intraoperative bleeding is a fewer. It is our belief that this method should be widely applied in the operation of graft-replacement of ascending aorta or aortic arch in the near future.

Aged↗

PubMed1992

Cell surface antigens expressed on polymorphonuclear cells in the peripheral blood from patients with inflammatory rheumatic diseases: two-color flow-cytometric analysis.

Cell surface antigens, such as CR3, Fc gamma RIII, cALLa and Leu 8 antigen, expressed on polymorphonuclear cells (PMN) in the peripheral blood (PB) are associated with certain functions of PMN. Functional alterations of PMN have been reported in some rheumatic diseases. In this study, therefore, the cell surface antigens were examined by 2-color flow-cytometry using monoclonal antibodies to clarify whether expressions of the antigens on PMN are abnormal in patients with rheumatic diseases including Behçet's disease (BD), rheumatoid arthritis (RA) and Sjögren's syndrome (SS). We found that expressions of CR3 and cALLa were increased on PB-PMN from patients with BD or RA, but not from those with SS. In BD, we further determined the phagocytic activity of PMN by a flow-cytometric method using fluorescent particles. The phagocytic activity was significantly higher in BD patients than in healthy controls, and correlated slightly with the expression of CR3 on PMN in the patients. In addition, prednisolone or colchicine seemed to decrease the expression of CR3 and/or cALLa in patients. The above results indicated that PB-PMN in BD and RA, but not SS, are phenotypically activated in vivo, and the activation probably reflects several cytokines and/or other stimuli to PMN produced in the inflammatory process.

Adult↗

PubMed1992

[Felty's syndrome].

Felty's syndrome is a variant of rheumatoid arthritis with a triad of leukopenia, splenomegaly and typical rheumatoid arthritis, and often accompanies the other extraarticular symptoms, such as subcutaneous nodules, lymphadenopathy, anemia, thrombocytopenia, leg ulcers, fever and weight loss. In addition to the decreased number of leukocyte, impaired functions of leukocytes were also revealed. These changes were considered as the cause of repeated infections, which was the major cause of death in Felty's syndrome. Splenectomy is not fully effective for leukopenia and for the repeated infection. Glucocorticoid therapy can increase leukocyte count, at least tentatively. It has been reported that gold was effective for leukopenia, repeated infection and skin ulcer. However, the definitive way of treatment of this syndrome based on the pathogenesis of this syndrome, remains to be established.

Adolescent↗

PubMed1992

[Choleretic effects of taurine on experimentally-induced intrahepatic cholestasis].

When a lymphokine, the cholestatic factor, is intravenously injected into rats through a mesenteric vein, remarkable reductions in bile flow and bile acid excretion are observed. However when taurine was injected with the cholestatic factor, the reduction in bile flow and bile acid excretion were significantly suppressed. Moreover, injection of taurine with cholestatic factor resulted in the decreases of both bile acid-dependent bile flow and vesicular transport but not bile acid-independent bile flow. Not significant choleretic effects were noted when taurine alone was administered to normal rats.

Animals↗

PubMed1992

[Host factors which influence the outcome of pneumonia in the elderly].

We examined 135 elderly patients with pneumonia to clarify the factors predicting on the outcomes of the elderly pneumonic patients. In the fatal cases respiratory symptoms such as cough and sputum, except for dyspnea were less frequent but pulmonary infiltrations on chest roentgenograms were more massive as compared with those in the survived cases. Thus, it was suggested that in the fatal cases the more advanced pneumonia had developed at the time when the diagnosis of pneumonia was made. The fatal cases showed hypoalbuminemia, hypocholesterolemia and hyponatlemia more frequently as compared with survived cases. Among these laboratory values, the decreased serum albumin concentration seemed to be most closely correlated with the fatal outcome of the elderly pneumonic patients. There were significant differences in the outcomes among three groups of the patients, those who were the prolonged bed-ridden, those with severe underlying diseases such as cancer and those treated as out-patients. The out patients showed the most favorable outcome and the prolonged bed-ridden patients the worst outcome. Approximately, 39% of the fatal cases were complicated with multiple organ failure. These results suggest that more important factors which affect the outcomes of pneumonia in the elderly may be not merely aging but the conditions of the host at onset of the disease.

Aged↗

PubMed1992

[A case of dimethyl sulfate intoxication manifested by persistent dyspnea].

A 35-year-old man had been exposed to the vapor of dimethyl sulfate which was split over the bed of a truck from an accidentally broken container. After receiving treatment at the critical care unit of our university hospital for respiratory failure, he was transferred to our ward with dyspnea persisting for one month. Chest X-ray showed diffuse nodular and infiltrative shadows and shadows suggestive of bronchial wall thickening. Bronchoscopy demonstrated tracheobronchial stenosis due to severe inflammation, and transbronchial lung biopsy revealed erosion and granulation in tissues of the bronchiolar walls. These findings suggested extensive inflammatory involvement of the respiratory tract extending from the trachea to the bronchioles. Treatment with antibiotics, especially agents with antipseudomonal activity, was effective against secondary pneumonia. Administration of corticosteroid for stenotic lesions of the airway was extremely beneficial. The clinical course of the respiratory lesion caused by dimethyl sulfate intoxication was following, including the bronchoscopic findings. The efficacy of treatment with corticosteroid and antibiotics was evaluated by successive bronchoscopic examinations of the lesions.

Adult↗

PubMed1991

Modification of histidine 56 in adrenodoxin with diethyl pyrocarbonate inhibited the interaction with cytochrome P-450scc and adrenodoxin reductase.

Three histidine residues of bovine adrenodoxin, His-10, His-56, and His-62, were modified with diethyl pyrocarbonate. The order of the modification among the three histidines were monitored by measuring the proton NMR spectra. The modified adrenodoxin exhibited reduced affinity for adrenodoxin reductase as determined in cytochrome c reductase activity. In the presence of cholesterol, the modified adrenodoxin induced a high spin form of cytochrome P-450scc on complex formation in the same manner as native adrenodoxin. The spectral titration showed that adrenodoxin modified with diethyl pyrocarbonate exhibited a 5-fold higher Kd value than that of native adrenodoxin. These effects of the modification of adrenodoxin on the affinities for the redox partners were not proportional to the number of modified histidines determined by the optical absorbance change at 240 nm. Modification of adrenodoxin up to 2 histidine residues did not affect the affinity for the redox partners, but further modification on the third one resulted in an increase of apparent Km in cytochrome c reductase activity by 2-fold and of Kd for cytochrome P-450scc by 5-fold. The 1H NMR spectra of the modified adrenodoxin unequivocally demonstrated that histidine residues at His-10 and His-62 reacted more readily with diethyl pyrocarbonate than His-56 did, indicating that modification of His-56 was responsible for the reduction of binding affinities of adrenodoxin for redox partners. These results are consistent with the proposal that the residue of His-56 in adrenodoxin has an essential role in the electron transfer mechanism where adrenodoxin functions as a mobile shuttle.

Adrenodoxin↗

PubMed1991

Genetic factors and suppression of metastatic ability of prostatic cancer.

Progression of prostatic cancer from nonmetastatic to high metastatic ability may involve the loss of a metastasis suppressor gene. To test this possibility, nonmetastatic and highly metastatic Dunning rat prostatic cancer cells were fused. Hybrid clones were isolated which conserved the chromosomes from their parental cells. When these hybrids were injected into animals, none developed distant metastases. When these nonmetastatic primary tumors were passaged in vivo, occasional animals developed distant metastases. Cytogenetic analysis of eight of these metastatic revertants demonstrated a consistent loss of a copy of a normal chromosome 2. Although previous studies have demonstrated that specific chromosomes can inhibit tumorigenicity in cell fusion experiments, this is the first study to show that prostatic cancer metastasis is associated with the loss of a specific chromosome. Furthermore, these studies suggest that a metastasis suppressor gene for rat prostatic cancer is located on chromosome 2.

Animals↗

PubMed1991

A novel recombinant tumor necrosis factor-alpha mutant with increased anti-tumor activity and lower toxicity.

We prepared a novel recombinant tumor necrosis factor-alpha (TNF) mutant (mutant 471), in which 7 N-terminal amino-acids were deleted and Pro8Ser9Asp10 was replaced by ArgLysArg, and compared its biological activity with that of wild-type recombinant TNF. Mutant 471 had a 7-fold higher anti-tumor activity against murine L-M cells in vitro, and a higher binding activity to TNF receptors on L-M cells, than wild-type TNF. Furthermore, mutant 471 showed a higher anti-tumor effect on murine Meth A-HM tumors transplanted into BALB/c mice, with complete regression of the tumors being observed in the animals. The possible cachectin activity of mutant 471 was almost the same as that of wild-type TNF. The acute lethal toxicity of mutant 471 in beta-D-galactosamine-sensitized C3H/HeJ mice was 18 times lower than that of wild-type TNF. These results suggest that mutant 471 might be a more promising anti-cancer agent than wild-type TNF.

Amino Acid Sequence↗

PubMed1991

Binding specificity of D-mannose 6-phosphate receptor of rabbit alveolar macrophages.

The existence of terminal D-mannosyl 6-phosphate groups (Man-6-P) was required (for an inhibitor) to exert a strong inhibitory potency against the binding of bovine serum albumin (BSA) conjugated with 17 molecules of penta-D-mannose 6-phosphate [(M5P)17-BSA] to the Man-6-P receptor in rabbit alveolar macrophages. In addition, the underlying oligosaccharide structures, such as linkage mode between the nonreducing sugar group and the penultimate sugar residue, and the length of sugar chain also affected the inhibitory potency in this system. In general, the oligosaccharides with an alpha-(1----2)-linked Man-6-P unit gave stronger inhibitory potencies than those with an alpha-(1----3)- or alpha-(1----6)-linked Man-6-P unit. Trisaccharides containing a terminal Man-6-P group were more potent inhibitors than disaccharides. A synthetic, branched, and divalent ligand, which does not have a penultimate sugar residue, gave about the same level of inhibitory potency as Man-6-P itself. The "cluster effect" was observed in this system, i.e., as the number of Man-6-P units conjugated to BSA [(Man-6-P)5,5,8, and 46-BSA] increased, the stronger inhibitory potencies were observed with decreasing I50 values of 1.93, 1.36, and 0.0345 microM, respectively. Synthetic divalent oligosaccharides also showed higher inhibitory potencies than the corresponding monovalent oligosaccharides.

Animals↗

PubMed1991

Proton nuclear magnetic resonance investigation of adrenodoxin. Assignment of aromatic resonances and evidence for a conformational similarity with ferredoxin from Spirulina platensis.

Bovine, porcine and sheep adrenodoxin, and the trypsin-resistant form of bovine adrenodoxin have been studied by one- and two-dimensional 1H-NMR spectroscopy. Assignment of the resonances for all the aromatic amino acids with resolved aromatic resonances have been made by correlating NMR spectra with the amino acid sequences from various species. Slowly exchanging amide protons and downfield shifted alpha-protons of His10 and Phe11 suggest possible involvement in beta-sheet structure. The effects on the assigned resonances due to the specific spin-label with a nitroxide radical at Cys95 have been analyzed on a two-dimensional 1H-NMR spectrum. The present results provide evidence for a structural similarity with a model for the structure of adrenodoxin based on a sequence alignment with that of Spirulina platensis ferredoxin, for which X-ray crystallographic data is available. epsilon-Methyl groups of Met120 and Met122 have been assigned by comparing 1H-NMR spectra of adrenodoxin with those of the trypsin-resistant form of adrenodoxin which is specifically cleaved at Arg115. epsilon-Methyl groups of Met120 and Met122 have an exceptionally long longitudinal relaxation time compared with those of valyl and leucyl methyl groups, suggesting that the COOH-terminal peptide spanning over 13 amino acids rotates rather freely in the solvent.

Adrenodoxin↗

PubMed1991

Conformational change of adrenodoxin induced by reduction of iron-sulfur cluster. Proton nuclear magnetic resonance study.

Bovine adrenodoxin in the reduced form has been measured by one- and two-dimensional 1H NMR spectroscopy. By comparing the spectrum of reduced adrenodoxin with that of the oxidized protein, resonances have been assigned for the aromatic residues. The spin-lattice relaxation time for the resonances due to histidine residues was found to depend on the reduction state of adrenodoxin. The distance from the paramagnetic center is calculated by using the Solomone-Bloembergen equation. The resonances from Tyr-82 and Ala-81 show large chemical shift changes upon reduction of adrenodoxin. The conformational change of adrenodoxin manifested by chemical shift difference between reduced and oxidized forms is found in the sequence around Tyr-82 and Ala-81. Modification with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide at Glu-74, Asp-79, and Asp-86 inhibited the interaction with both adrenodoxin reductase and cytochrome P-450scc (Lambeth, D. J., Geren, L. M., and Millett, F. (1984) J. Biol. Chem. 259, 10025-10029; Geren, L. M., O'Brien, P., Stonehuerner, J., and Millett, F. (1984) J. Biol. Chem. 259, 2155-2160). Thus, the sequence of these amino acids was assigned to the interaction site with the redox partners. The present 1H NMR investigation of adrenodoxin demonstrates that a conformational change upon reduction of the iron-sulfur cluster occurs in the sequence of negatively charged amino acids that is a putative site for interaction with redox partners. This could offer the structural basis of the electron transfer mechanism in which adrenodoxin functions as a mobile electron carrier.

Adrenodoxin↗

PubMed1991

Ligand-binding characteristics of rat serum-type mannose-binding protein (MBP-A). Homology of binding site architecture with mammalian and chicken hepatic lectins.

Sugar-binding characteristics of rat serum mannose-binding protein (MBP) were studied using the carbohydrate-recognition domain of this protein expressed from a cloned cDNA. To assess the binding affinity of various test compounds, they were added as inhibitors in a binding assay in which 125I-MBP was incubated with yeast cells and the extent of binding was estimated from the radioactivity associated with the pelleted cells. The results of such inhibition assays suggest that MBP has a small binding site which is probably of the trough-type. The 3- and 4-OH of the target sugar are indispensable, while the 6-OH is not required. These characteristics are shared by the rat hepatic lectin and chicken hepatic lectin, both of which are C-type lectins containing carbohydrate-recognition domains highly homologous to that of MBP. Apparently, the related primary structures of these lectins give rise to similar gross architecture of their binding sites, despite the fact that each exhibits different sugar binding specificities.

Animals↗

PubMed1991

Last-order interneurones controlling activity of elbow extensor motoneurones during forelimb fictive locomotion in the cat.

Last-order interneurones, which were identified by antidromic invasion from the elbow extensor motor nuclei (triceps brachii), were examined for rhythmic activity during fictive locomotion. Last-order neurones with activity modulated were divided into 3 groups: one exhibited flexor-like activity, another extensor-like, and the third activity which had properties of both. Flexor-like neurones, presumably inhibitory, were located in the rostral segments (C6-C7), whereas extensor-like ones, presumably excitatory, were located in the caudal (C7-T1). Neurones of the third group were found in the most caudal segments (C8-T1). The results seem to suggest the existence of functional localization in the stepping generator.

Animals↗

PubMed1991

Association of the complement allele C4AQ0 with primary Sjögren's syndrome in Japanese patients.

We studied allotypes of the fourth component of complement (C4) and factor B in 76 patients with Sjögren's syndrome (SS) and in 63 normal subjects. C4A-null (C4AQ0) was found in 10 of 28 patients who had primary SS, compared with 1 of 63 control subjects (P less than 0.005). In contrast, no significant difference in the frequency of any C4 allotype was observed between patients with secondary SS and control subjects. An association of HLA-DRw53 with primary SS in Japanese patients has been reported. Since there is no linkage disequilibrium between DRw53 and C4AQ0, it is possible that at least 2 genes in the major histocompatibility complex may determine susceptibility to the development of primary SS in the Japanese population.

Autoimmune Diseases↗

PubMed1991

Cytochrome P-45011 beta in rat brain.

The presence of cytochrome P-45011 beta in rat brain was studied by immunohistochemistry using polyclonal rabbit antibodies raised against purified bovine adrenocortical P-45011 beta, which is involved in the steroid 11 beta-hydroxylation and glucocorticoid formation. The results showed that cytochrome P-45011 beta immunoreactivity is selectively localized to the tracts of myelinated fibers throughout the brain. The specificity of immunohistochemical stainings with P-45011 beta antibodies was established by control tests including nonimmune rabbit immunoglobulin Gs and P-45011 beta antibodies absorbed with purified antigen. Western immunoblots of homogenates from different brain areas with P-45011 beta antibodies, together with biochemical enzymatic assays for cytochrome P-45011 beta monooxygenase activity in these homogenates, confirmed the selective localization of this enzyme observed with immunohistochemistry. Cytochrome P-45011 beta and 11 beta-hydroxylase activity were detected in a homogenate from the cortical white matter (brain area rich in myelinated fibers) as in that from the rat adrenal, but were not detectable in a homogenate from the cerebral cortex (brain area poor in myelinated fibers). Furthermore, quantitation of the P-45011 beta bands on the immunoblots by the areal density revealed that the cortical white matter contains approximately 1.4 pmol of cytochrome P-45011 beta/mg of tissue protein, the value of which was about one sixth of the corresponding value estimated in the rat adrenal. This relatively high content of cytochrome P-45011 beta was also reflected in a relatively high level of 11 beta-hydroxylase activity measured in a homogenate of this brain area by biochemical enzymatic assays using [4-14C]-11-deoxycorticosterone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex↗

PubMed1991

H-ras expression, genetic instability, and acquisition of metastatic ability by rat prostatic cancer cells following v-H-ras oncogene transfection.

To study the relationship between metastatic ability, mutated H-ras expression, and genetic instability, a cloned, nonmetastatic rat prostatic cancer cell line (AT2.1) was transfected with the v-H-ras oncogene. The parental AT2.1 clone, 4 control transfectants (Neo/Only), and 9 v-H-ras transfectants (Neo/Ras) were characterized with regard to their H-ras content by using Southern, Northern, and Western blot analysis and their biological behavior in vivo. Following s.c. inoculation in syngeneic rats, all transfectants produced tumors. All 4 (Neo/Only) transfectants like the parental untransfected cell were non-metastatic. Six of 9 Neo/Ras transfectants were metastatic to the lungs and lymph nodes, while the other 3 Neo/Ras transfectants were not metastatic. There was no simple dose-response relationship between the level of v-H-ras integration, mRNA or p21 protein expression, and the development of metastatic ability by the Neo/Ras transfectants. Cytogenetic analysis demonstrated that the frequency of additional structural and/or additional numerical chromosomal changes among the Neo/Ras transfectants was significantly higher than that in the Neo/Only transfectants (P less than 0.05). Loss of chromosome 10 was observed in all of the Neo/Ras transfectants, whereas that was observed in only one of the 4 Neo/Only transfectants (P less than 0.05). There were no specific chromosomal changes, however, which were statistically correlated with the development of metastases in the Neo/Ras transfectants. These results demonstrate that development of the metastatic ability in AT2.1 cells is not a single-step reaction regulated by the level of H-ras expression alone, but rather a complex process requiring additional events. One of the additional events appears to be an increase in genetic instability and cytogenetic changes following v-H-ras transfection.

Animals↗

PubMed1991

Effects of irsoglandine maleate in an experimentally-induced acute hepatic failure model using mice.

When heat-killed Propionibacterium acnes was intravenously injected into mice followed by an intravenous injection of a small amount of Gram-negative lipopolysaccharide seven days later, most of the mice died of massive hepatic cell necrosis within 24 hours. However, when irsoglandine maleate, an anti-ulcer agent, was administered to mice during the period of experimental induction of acute hepatic failure, the survival rate, serum transaminase levels and histological changes of the liver remarkably improved. These results suggested that irsoglandine maleate may have protective effects on the liver in our experimentally-induced acute hepatic failure model using mice. Therefore, in the absence of a definitive therapy for fulminant hepatitis, irsoglandine maleate may be a promising therapeutic agent.

Animals↗