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Biomedical subjects

H Yoshimura

Publications and source records attributed to H Yoshimura.

At least 163 records · Page 9Linked to original sources
PubMed1996

[A new embolic material: super absorbent polymer (SAP) microsphere and its embolic effects].

SAP-Microsphere (sodium acrylic acid-vinyl alcohol copolymer) has the ability to absorb fluids within a few minutes and increase its diameter. Its diameter can also be calibrated. The diameters in ionic contrast material and human serum are 2.1 and 3.5 times larger, respectively, than the original size. It can pass through a microcatheter with an ionic contrast material, and swells at the occluding point into the desired size. It can be recognized under fluoroscopy due to its absorption of contrast material. A total of 10 rabbit kidney embolizations were done followed by resection in 1-14 weeks. Recanalization was absent in all cases. No adhesion to the perirenal tissue was found. Limited reactive change in endothelial cells was found at one week. No changes in the smooth muscle layer were found at any time during the study. Limited infiltration of neutrophil cells was found in perivascular tissue within a period of one week. SAP-Microspheres maintained their spherical shape during a 14-week period. Extensive fibrosis and calcification were found after 4 weeks. SAP-Microspheres are promising as an embolic agent to obtain satisfactory results of embolization therapy.

Absorption↗
PubMed1996

[An experience of right pneumonectomy in the elderly (aged 82) lung cancer].

Lung cancer in the elderly (over 80 years or over the average life) isn't generally performed surgical treatment, but we performed right pneumonectomy to aged 82 who had taken a right upper lobe's primary squamous cell lung carcinoma. He recovered well. Especially in general pneumonectomy should be avoided to over aged 80 because of the high death rate compare with other operative way (Lobectomy, Segmentectomy, Wedge resection etc.). But we think the operative indication should be determined synthetically (good performance status, not so progressive clinical staging, no existing another disease, etc.). We perform pneumonectomy in the elderly if patient's performance status is 0 or 1, and clinical staging is I or II, and the other laboratory data is good. But most important, we should explain exact information of the disease and perform surgical treatment in case it's received. We should take into consideration reduction surgery for prevention of complication without persisting in standard way of operation.

Aged↗
PubMed1996

Persistent c-fos expression in the brains of mice with chronic social stress.

The present study was conducted to demonstrate immunohistochemically, the sites of c-fos protein expression in the brains of mice subjected to acute and chronic social defeat stress. To induce social stress, mice were placed in situations of species-specific intermale aggression either only once or five times at 24 h intervals. Two hours after the single or fifth defeat stress, many c-fos immunoreactive neurons were observed in a variety of brain regions including the limbic system and sensory relay nuclei. The c-fos immunoreactive neurons in the brains of acute defeat mice decreased in number with time and the c-fos staining pattern of acute defeat mice became indistinguishable from that of normal control mice by 24 h after the single defeat stress. In contrast, chronic defeat stress induced persistent c-fos expression in the forebrain and brainstem even 24 h after the fifth defeat stress. In the forebrain of chronic defeat mice, the olfactory bulb, cingulate cortex, hippocampus, entire hypothalamus, septal nuclei and the amygdaloid complex, except for the central nucleus, were labeled intensely with c-fos antiserum. In the lower brainstem, nerve cells with c-fos immunoreactivity were seen mainly in ascending and descending sensory relay nuclei relevant to auditory and vestibular transmission, epicritic sensation (gracile and external cuneate nuclei), pain inhibition (central gray and raphe nuclei), and viscerosensory transmission (solitary tract nucleus). The differences in c-fos expression among the normal control, acute and chronic defeat mice were evaluated by an enumeration of the immunopositive neurons within each brain nucleus examined, and they were confirmed subsequently by statistical analysis. There was little c-fos expression in the nucleus putamen, lateral, ventral and posterior thalamic nuclei, pretectal nuclei, medial geniculate nucleus, red nucleus, substantia nigra, cerebellum, spinal cord, or cranial nerve nuclei. These findings suggest that chronic but not acute defeat stress causes persistent c-fos expression in more widespread brain regions than do any other stresses so far investigated. The present study may shed light on the central mechanisms by which behavioral abnormalities and/or chronic sociopsychological stress leads to the occurrence of abnormal behavior and/or psychosomatic disorders in experimental animals and humans.

Animals↗
PubMed1996

Non clamping anastomosis of the ascending and arch aneurysm using retrograde cerebral perfusion.

Twelve consecutive patients requiring surgery for replacement of ascending aortic aneurysms (n = 3), ascending arch aortic aneurysms (n = 2), or type A aortic dissections (n = 7) were treated without aortic cross clamping. Retrograde cerebral perfusion (RCP) with circulatory arrest (mean RCP time: 46.0 +/- 15.9 minutes, range 20 to 65 minutes) and continuous retrograde cardioplegia (mean cardiac ischemic time: 134.4 +/- 39.7 minutes, range: 40 to 180 minutes) were employed. In the patients with aortic dissection, the intimal tear at the origin of the brachiocephalic artery (BCA) was resected completely, the aortic wall was trimmed and closed with Teflon felt. The distal anastomosis was created using an open technique. Air and debris were completely evacuated by returning blood from the cerebral vessels and femoral artery. Then the artificial graft was clamped, and cardiopulmonary bypass resumed. The proximal anastomosis was performed during rewarming. The operations were elective in seven cases, and emergent in five cases. Graft replacement of the ascending aorta was performed in ten patients (including two BCA reconstructions). The remaining two patients were treated by patch repair (n = 1), primary anastomosis (n = 1). There were no perioperative deaths. One patient had a transient neurological deficit. The distal false lumen was occluded completely in five of seven patients with aortic dissections. The other two patients had a secondary tears in the descending aorta. Thus retrograde cerebral perfusion and continuous retrograde cardioplegia without aortic cross clamping is an effective technique in the replacement of the ascending and arch aorta.

Adult↗
PubMed1996

Characterization of Aeromonas hydrophila: a comparative study of strains isolated from diarrheal feces and the environment.

Thirty-five strains of Aeromonas hydrophila isolated from feces of diarrheal patients and from the environments were collected from Thailand and Japan. The physiological, biochemical, and serological characteristics, antibiotic resistance patterns and cell surface-related properties were compared. The diarrheal and environmental isolates of A hydrophila were found to be remarkably consistent in general culture and biochemical characteristics, with the exception of the reaction to D-arabinose in which the diarrheal strains were positive and environmental strains were negative. The plasmid patterns and cell surface-related properties of the environmental and diarrheal isolates were different. All strains produced Vero cell cytotoxin, hemolysin and lecithinase at 37 degrees, 30 degrees and 15 degrees C. In contrast, 83% of the environmental strains produced these virulence factors even at 4 degrees C. All strains indicated almost uniform susceptibility to the 16 antibiotics tested. Variations were found in the plasmid profile, toxin production in relation to the differences of temperature and cell surface-related properties of the strains. These variations between the clinical and environmental isolates could have potential as epidemiological markers for the sources of strains.

Aeromonas hydrophila↗
PubMed1995

A novel type of retinoic acid receptor antagonist: synthesis and structure-activity relationships of heterocyclic ring-containing benzoic acid derivatives.

A new series of heterocyclic ring-containing benzoic acids was prepared, and the binding affinity and antagonism of its members against all-trans-retinoic acid were evaluated by in vitro assay systems using human promyelocytic leukemia (HL-60) cells. Structure-activity relationships indicated that both an N-substituted pyrrole or pyrazole (1-position) and a hydrophobic region, with these linked by a ring system, were indispensable for effective antagonism. Among the compounds evaluated, optimal antagonism was exhibited by 4-[4,5,7,8,9,10-hexahydro-7,7,10,-10-tetramethyl-1-(3- pyridylmethyl)anthra[1,2-b]pyrrol-3-yl]benzoic acid (31), 4-[4,5,7,8,9,10-hexahydro-7,7,10,10-tetramethyl-1-(3-pyridylmethyl)-5- thiaanthral[1,2-b]pyrrol-3-yl]benzoic acid (40), and 4-[4,5,7,8,9,10-hexahydro-7,7,10,10-tetramethyl-1-(3- pyridylmethyl)anthra[2,1-d]pyrazol-3-yl]benzoic acid (55), all of which possess a 3-pyridylmethyl group at the five-membered ring nitrogen atom.

Benzoates↗
PubMed1995

Metabolism of highly persistent PCB congener, 2,4,5,2',4',5'-hexachlorobiphenyl, by human CYP2B6.

Metabolism of 2,4,5,2',4',5'-hexachlorobiphenyl was studied with cDNA-expressed human P450 2B isoform, CYP2B6. 3-Hydroxy-2,4,5,2',4',5'-hexachlorobiphenyl was identified as a major metabolite, and the formation activity was compared with that of dog CYP2B11 and guinea pig P450GP-1. The activity of 3-hydroxylation was comparable with that of P450GP-1, but one-tenth of CYP2B11. These results indicate that P450 2B in humans as well as other animal species can metabolize 2,4,5,2',4',5'-hexachlorobiphenyl, and the reason why this PCB congener remained most abundantly in human bodies is discussed.

Animals↗
PubMed1995

Ciliary neurotrophic factor prevents ischemia-induced learning disability and neuronal loss in gerbils.

Ciliary neurotrophic factor (CNTF) has been shown to have potent neurotrophic activity on peripheral and central neurons in vitro and in vivo. However, it remains to be determined whether or not CNTF rescues hippocampal CA1 neurons from lethal ischemia and prevents ischemia-induced learning disability. In the present in vivo study, we infused CNTF continuously for 7 days into the lateral ventricle of gerbil starting 2 h before 3-min forebrain ischemia. CNTF infusion prevented the occurrence of ischemia-induced learning disability in a dose-dependent manner as revealed by the step-down passive avoidance task. Subsequent light and electron microscopic examinations showed that pyramidal neurons in the CA1 region of the hippocampus as well as synapses within the strata moleculare, lacunosum/radiatum and oriens of the region were significantly more numerous in gerbils infused with CNTF than in those receiving vehicle infusion. These findings suggest that CNTF has a trophic effect on ischemic hippocampal neurons.

Animals↗
PubMed1995

Purification and characterization of a newly identified isoform of cytochrome P450 responsible for 3-hydroxylation of 2,5,2',5'-tetrachlorobiphenyl in hamster liver.

In the hamster liver, 2,5,2',5'-tetrachlorobiphenyl (TCB) is metabolized to 3-hydroxy- and 4-hydroxy-2,5,2',5'-TCB to a similar extent, and formation of the former metabolite is stimulated by phenobarbital pretreatment of the animals, while that of the latter metabolite is stimulated by 3-methylcholanthrene pretreatment. In the present study, we identified a new isoform (designated P450HPB-1) of cytochrome P450 which proved to be phenobarbital-inducible and responsible for 3-hydroxylation of this TCB isomer. This isoform was purified from liver microsomes of phenobarbital-treated hamsters and characterized. P450HPB-1 has a molecular mass of 50 kDa, determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the absorption maxima of the oxidized form at 417 nm and of the reduced CO-complex form at 450 nm. The sequence of 28 amino acids of P450HPB-1 at the amino-terminal has a 68% similarity with those of rat P450 2B1 and mouse P450 2b10, 57% similarity with that of guinea pig P450GP-1, and 54% similarity with that of guinea pig P450GP-1, and 54% similarity with those of rabbit P450 2B4 and dog P450 2B11. P450HPB-1 in the reconstituted system catalyzed the 3- but not 4-hydroxylation of 2,5,2',5'-TCB, at a rate of 19.0 pmol/min/nmol P450. The isoform also has high catalytic activity for 17-oxidation of testosterone but low activity for the N-demethylation of benzphetamine and 16 alpha- and 16 beta-hydroxylations of testosterone. In microsomal metabolism of 2,5,2',5'-TCB, rabbit antiserum against P450HPB-1 almost completely inhibited 3- but not 4-hydroxylation. Immunoblot analysis of hamster liver microsomes revealed that P450HPB-1 was constitutive and phenobarbital-inducible but was decreased by pretreatment with 3-methylcholanthrene or 3,4,5,3',4'-pentachlorobiphenyl. These results suggest that P450HPB-1 belongs in the P450 2B subfamily and apparently plays a major role in the 3-hydroxylation of 2,5,2',5'-TCB, in hamster liver.

Amino Acid Sequence↗
PubMed1995

Curative resection of gastric cancer: limitation of peritoneal lavage cytology in predicting the outcome.

Patients with stage T3N0-2M0 gastric carcinoma (n = 108) were studied for relevant prognostic factors. Peritoneal lavage cytology (PLC) was performed in all. In univariate analysis, 5-year survival rates were better with smaller serosal invasion (diameter < 3.0 cm vs. > or = 3.0 cm, 61% vs. 37%, P < 0.05) and fewer metastatic nodes (< or = 5 vs. > or = 6, 57% vs. 29%, P < 0.05). In multivariate analysis, only these two factors were significant. The predictive value of PLC was not shown in both univariate and multivariate analyses. Peritoneal recurrence occurred in 14 (22%) of 77 patients with negative PLC, and in 3 (18%) of 17 with positive PLC, the difference being not significant. Our results indicate that PLC is insensitive in predicting the development of peritoneal recurrence. Its role in the estimation of survival is limited, as many will die of visceral or locoregional recurrence if not of peritoneal dissemination.

Aged↗
PubMed1995

Overexpression of P-glycoprotein in untreated AFP-producing gastric carcinoma.

P-glycoprotein (P-gly), which is responsible for the phenotypic expression of multidrug resistance in cancerous tissue was stained immunohistochemically in previously untreated alpha-fetoprotein (AFP)-producing (n = 20) and nonproducing gastric cancers (n = 20). P-gly, AFP, and carcinoembryonic antigen(CEA) were stained in formalin-fixed paraffin-embedded tissue sections immunohistochemically using the monoclonal antibody JSB-1, anti-AFP, and anti-CEA, respectively. DNA ploidy pattern was determined by Fluorescence Activated Cell Sorter (FACS) analyzer. P-gly was significantly overexpressed in AFP producing gastric cancers (60%) than in AFP nonproducing ones (20%) (P < 0.01). When the result of P-gly staining was analyzed among the AFP-positive cases, P-gly positivity did not emerge either as a significant prognostic factor or as a predictor of the metastatic potentiality of the tumor. The intrinsic overexpression of P-gly in AFP producing gastric cancers proves its biological and morphological similarities to hepatocellular carcinoma. The significantly (P < 0.05) higher incidence of P-gly in diploid tumors indicate that expression of this phenotype might be related to the differentiation of the tumor. P-gly was overexpressed in AFP producing gastric carcinoma and the existing drug resistance, frequent recurrence, and poor prognosis might be explained by presence of P-gly in this carcinoma.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

Control of crystal forms of apoferritin by site-directed mutagenesis.

Surface charges of protein molecules are not only important to biological functions but also crucial to the molecular assembly responsible for crystallization. Appropriate alteration in the surface charge distribution of a protein molecule induces new molecular alignment in the proper direction in the crystal and, hence, controls the crystal form. Apoferritin molecules are known to crystallize in two- and three-dimensional forms in the presence of cadmium ions, which bridge neighboring protein molecules. Here we report a controlled transformation of the apoferritin 2-D crystal by site-directed mutagenesis. In mutant apoferritin, two amino acid residues binding a cadmium-ion through their negative charge, were replaced by one type of nonionic amino acid residues. The amino acid residues, Asp-84 and Gln-86 in the sequence of recombinant (i.e., wild-type) horse L-apoferritin, were replaced by Ser. The wild-type apoferritin yielded a hexagonal lattice 2-D crystal in the presence of cadmium ions. In contrast, the mutant apoferritin yielded two types of oblique crystals independent of the presence of cadmium ions. Image reconstruction of electron micrographs of the mutant crystals made clear that the mutant apoferritin molecules oriented themselves with the 2-fold symmetry axis perpendicular to the crystal plane in both crystals, while the wild-type apoferritin molecules oriented themselves with the 3-fold symmetry axis perpendicular to the crystal plane. The changes of crystal forms and molecular orientation in the 2-D crystals were well explained by a change of the electrostatic interactions induced by the mutagenesis.

Animals↗
PubMed1995

Squamous cell carcinoma of the esophagus after partial gastrectomy.

Twelve patients (10.4%) had a history of partial gastrectomy among the 115 patients with squamous cell carcinoma of the esophagus. The clinical characteristics, nutritional parameters, and incidences of esophagitis of the resected specimens were investigated between 11 patients with esophageal carcinoma who had partial gastrectomy for peptic ulcer diseases (Group A) and 103 patients with esophageal carcinoma without any previous history of gastrectomy (Group B). Age, sex, tumor location, clinical stages, and cigarette and alcohol consumption were not different between the two groups. Hemoglobin, mean corpuscular volume, and mean corpuscular hemoglobin level in Group A were lower than those in Group B (p < 0.05). Serum zinc level in Group A was lower than that in Group B, but this difference was not significant. There was no difference in the incidences of esophagitis between the two groups. In conclusion, there is an association between partial gastrectomy and later development of squamous esophageal carcinoma. The role of malnutritional factors and gastroesophageal reflux, however, remain unclear. The long-term follow-up of patients after partial gastrectomy is warranted.

Aged↗
PubMed1995

Plasma concentrations and tissue residues of bicozamycin given orally to pigs.

Bicozamycin was dissolved in water and administered to pigs by stomach tube at 40 mg/kg once daily for 7 consecutive days. The plasma concentration was determined on days 1 and 7 of the dosing period. The mean (+/- SD) peak plasma concentrations were 2.06 +/- 0.36 micrograms/ml at 3.08 +/- 0.80 h on day 1 and 2.36 +/- 1.32 micrograms/ml at 2.80 +/- 0.74 h on day 7, the elimination half-lives being 3.80 +/- 0.92 h and 2.43 +/- 1.41 h, respectively. The mean areas under the plasma concentration-time curves were 15.88 +/- 2.18 (micrograms h)/ml on day 1 and 12.31 +/- 6.98 (micrograms h)/ml on day 7. These pharmacokinetic parameters did not differ between days 1 and 7, suggesting that there was no accumulation in the plasma after consecutive oral dosing. The residues in kidney, liver and muscle were examined in pigs slaughtered on days 1, 3 and 5 after the last dosing. One day after withdrawal, residues were found in the kidneys of all three pigs examined, at a mean concentration of 0.26 microgram/g, and in muscle from one pig, but not in liver from any of the pigs. Bicozamycin was not detected in any of the samples taken 3 or 5 days after withdrawal.

Administration, Oral↗
PubMed1995

Truncus arteriosus with interrupted aortic arch: successful correction using autologous flap.

A newborn baby with type II truncus arteriosus and type B interrupted aortic arch was successfully treated by creating a pulmonary tract using autologous flap made from truncal wall without excision of the pulmonary artery and by reconstructing the aortic arch with direct anastomosis. This method provided excellent hemodynamics with wide reconstruction of the pulmonary tract without conduit.

Anastomosis, Surgical↗
PubMed1995

Metabolism of delta 9-tetrahydrocannabinol by cytochrome P450 isozymes purified from hepatic microsomes of monkeys.

The most abundant metabolite of delta 9-tetrahydrocannabinol (delta 9-THC) formed with hepatic microsomes of monkeys was 11-OH-delta 9-THC, followed by 8 alpha-OH-, 8 beta-OH- and 3'-OH-delta 9-THCs. Two cytochrome P450 isozymes, P450RM-A and P450JM-C, were purified from monkey hepatic microsomes and found to have a molecular weight of 51,000. In the reconstituted system, the activities of P450RM-A towards formation of 11-OH-, 8 alpha-OH-, 8 beta-OH- and 3'-OH-delta 9-THCs were 19-, 40-, 22- and 10-fold higher, respectively, than the corresponding activities of the hepatic microsomes. The activity of P450JM-C towards formation of 3'-OH-delta 9-THC was 10-fold higher than that of P450RM-A, while the activities of both isozymes for 11- and 8 alpha-hydroxylation were not so much different and the 8 beta-hydroxylation activity was 14-fold higher in P450RM-A than in P450JM-C. Antibodies against P450RM-A and P450JM-C markedly inhibited the microsomal formation of 11-OH- and 8 alpha-OH-delta 9-THCs, and 3'-OH-delta 9-THC, respectively. These results suggest that P450RM-A and P450JM-C are major isozymes responsible for the formation of 11-OH- and 8 alpha-OH-delta 9-THCs, and 3'-OH-delta 9-THC, respectively, in monkeys.

Amino Acid Sequence↗