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Biomedical subjects

A Tamura

Publications and source records attributed to A Tamura.

At least 379 records · Page 21Linked to original sources
PubMed1990

[Shape change of erythrocyte induced by plasma during cardiopulmonary bypass for open-heart surgery].

Effects of plasma of the blood under extracorporeal circulation (EC) on erythrocyte shape was determined on 14 patients undergoing open-heart surgery with cardiopulmonary bypass. Reversible echinocytosis was observed under an unfixed condition by mixing washed erythrocytes from normal volunteers with plasma of the patients' blood taken during EC. Either the plasma at the start or at the end of EC had no effect on echinocyte formation, while, the plasma obtained 2-3 hr after the onset of EC induced the most advanced stages of echinocytosis. Only the protein fraction after gel (sephadex G-25) filtration of the plasma induced the echinocytosis. Preheating the plasma at 56 degrees C for 30 min did not destroy the shape-transforming activity of the plasma. The plasma fatty acid/protein ratio was transiently increased with prolongation of EC and the ratio became maximum at 2-3 hr of EC, whereas the plasma cholesterol/protein ratio was kept constant during EC. Fatty acid content of the patients' erythrocytes was also increased accompanying the increase in plasma fatty acid/protein ratio. Therefore, it was suggested that the fatty acid incorporated from the patients' plasma into the cell membrane of the erythrocytes induced the echinocytosis.

Cardiopulmonary Bypass↗
PubMed1990

[Mixed blast crisis with the cytogenetic evidence of three clonal evolutions].

A 46-year-old man was diagnosed as having chronic myelogenous leukemia (CML) in chronic phase in Dec. 1985. In Dec. 1987, anemia and leukocytopenia progressed, and the percentage of blast cells increased in the bone marrow. The blast cells were lymphoblastoid and positive for TdT. It was treated as a lymphoid crisis with vincristine and prednisolone, and complete remission was achieved. However, the blasts (11%) were observed in the bone marrow in Mar. 1988, and the chromosomal analysis revealed 46, XY, t (2q-; 11q+), t (9q+; 22q-) in 13 out of 20 cells. In June, the percentage of the blasts increased again, but chromosomal analysis showed a different karyotype, 46, XY, t(2p-; 11p+), t(9q+; 22q-) which was observed in 9 out of 10 cells. Then, myeloblastoid cells increased rapidly in spite of the chemotherapy in Dec. 1988. The chromosomal analysis showed 46, XY, 2p-, 7q-, 9q+, 11p+, 22q- in all analyzed cells. The rearrangement of the bcr gene could be detected by the Southern blotting. The blasts were positive for CD7, CD11, CD13, CD33, CD36, CD41 and CD42, suggesting that the blasts had the surface phenotypes of both myeloid and megakaryocytoid-lineage. This is a case with the mixed blast crisis that changed from the lymphoid to the myelo-megakaryocytoid in nature, in which three clonal evolutions were observed during the clinical course.

Antigens, CD↗
PubMed1990

Increased plasma plant sterol levels in heterozygotes with sitosterolemia and xanthomatosis.

Plasma sterol levels in a family of sitosterolemia and xanthomatosis were determined by a high performance liquid chromatography. Three affected siblings manifested marked xanthomatosis including subcutaneous soft tissues and generalized atherosclerosis. Two other siblings as well as children of the patients did not show such clinical symptoms and signs. Plasma levels of cholesterol, sitosterol, campesterol, and cholestanol in three affected subjects were 190 +/- 18.5, 25.9 +/- 11.6, 16.1 +/- 7.8, 1.84 +/- 0.92 mg/dl (mean +/- SD), respectively. Four daughters of the affected subjects, who should be considered as obligatory heterozygotes, showed moderately increased levels of these sterols (195 +/- 41.7, 1.33 +/- 0.44, 1.56 +/- 0.69, 0.80 +/- 0.28 mg/dl), which were significantly higher than those of normal subjects. Treatment with cholestyramine had little effect on the increased plasma plant sterol levels, but markedly decreased plasma cholestanol concentrations in two affected siblings. This report presents the clinical features of the patients with sitosterolemia and xanthomatosis and also demonstrates that heterozygotes with this disorder have increased plasma levels of plant sterols as well as cholestanol, and suggests that this rare disease might be inherited as an autosomal co-dominant trait in certain cases. The data also indicate that cholestyramine administration was not effective in this family for treatment of sitosterolemia.

Adult↗
PubMed1989

Allopurinol inhibits uric acid accumulation in the rat brain following focal cerebral ischemia.

Uric acid (UA) in the rat brain was measured by HPLC with an electrochemical detector following focal ischemia. At 24 h after the operation, the UA level in the ischemic center was 105.47 +/- 8.39 nmol/g tissue, whereas it was 8.36 +/- 1.86 in the sham-operated group. Allopurinol, xanthine oxidase inhibitor, almost completely inhibited this UA accumulation. These data demonstrate that the UA increase in the ischemic brain is due to the xanthine oxidase reaction.

Allopurinol↗
PubMed1989

Homozygous hypobetalipoproteinemia with spared chylomicron formation.

Thirteen members of a family carrying a gene for pedigree of hypobetalipoproteinemia were analyzed for lipoprotein compositions, apolipoprotein (apo) B levels, and apo B isoforms. Judging from low density lipoprotein (LDL)-cholesterol (Chol) and apo B levels, a 75-year-old proband, a father who died of unknown fever, thrombopenia, and anemia, and his wife were heterozygous for hypobetalipoproteinemia. The proband had ataxic movement of hands and gait disturbance in later life. Three of four living siblings had extremely low levels of LDL-Chol (6 mg/dL) and LDL-apo B (2 mg/dL), and were postulated to have homozygous hypobetalipoproteinemia. Electrophoresis revealed marked deficiency of apo B-100, although trace amounts were noted in LDL. In contrast, apo B-48 was present in chylomicrons obtained after a fatty meal in the two patients with homozygous hypobetalipoproteinemia, indicating a selective deficiency of apo B-100 but not apo B-48. The defect in these patients seemingly is different from abnormal apo B-37 reported recently for a family with hypobetalipoproteinemia. Clinically, acanthocytotic red blood cells (8% to 12%), fatty liver, and low levels of serum lipid-soluble vitamins A and D were noted in homozygotes. One heterozygous sibling had 26 mg/dL LDL-Chol and 5 mg/dL LDL-apo B levels. All seven subjects in the third generation had low levels of Chol (85 to 140 mg/dL), LDL-Chol (40 to 63 mg/dL) and LDL-apo B (10 to 20 mg/dL). They also showed mild acanthocytosis (0.5% to 2%) and a decrease of fat-soluble vitamins in plasma.(ABSTRACT TRUNCATED AT 250 WORDS)

Acanthocytes↗
PubMed1989

Clinical study of OKY-046, a thromboxane synthetase inhibitor, in prevention of cerebral vasospasms and delayed cerebral ischaemic symptoms after subarachnoid haemorrhage due to aneurysmal rupture: a randomized double-blind study.

A double-blind study was conducted at 48 neurosurgical services in Japan to investigate the usefulness of OKY-046, an imidazole derivative and a thromboxane synthetase inhibitor, on cerebral vasospasm and cerebral ischaemic symptoms in patients with ruptured cerebral aneurysms. OKY-046 was administered in two daily doses of 80 mg (L group) and 400 mg (H group), and compared with a group given a placebo (P group). The following results were obtained: the occurrence of cerebral vasospasm was significantly lower in the L group than in the P group; the development of low density area (LD) in CTs was significantly lower in both the L and H groups than in the P group; motor paralysis in the L group improved significantly sooner, and that in the H group tended to improve sooner than that in the P group; in subjects with severe vasospasm, the incidence of LD was significantly lower, with better functional prognosis, in the L group than in the P group; in subjects with severe grades on the Glasgow Coma Scale (GCS), Japan Coma Scale (JCS) or High Density (HD) Score the functional prognosis at 1 month after the aneurysmal rupture was significantly better in the L group than in the P group, though no significant differences were seen in the overall investigation; there were no significant differences among the three groups in the development of either laboratory-determined abnormality or of adverse reactions. It is thus concluded that OKY-046 is clinically useful at a dose of 80 mg/d for cerebral vasospasm and cerebral ischaemic symptoms after subarachnoid haemorrhage (SAH) caused by aneurysmal rupture.

Acrylates↗
PubMed1989

Cerebral uric acid, xanthine, and hypoxanthine after ischemia: the effect of allopurinol.

The existence of uric acid in mammalian brain was recently reported, but it has not yet become a consensus. The mammalian brain has been thought to lack xanthine oxidase, which catalyzes hypoxanthine to xanthine and xanthine to uric acid as the last steps of ATP degradation in other tissue. Using high-performance liquid chromatography, we performed assays for hypoxanthine, xanthine, and uric acid in rat brain after cerebral ischemia. It was confirmed that all three substances showed significant augmentation in the removed brains and that the chronological order of those increases corresponded to the order in the metabolic pathway. Allopurinol, a specific inhibitor of xanthine oxidase, significantly suppressed the increases in uric acid and xanthine, and a compensatory accumulation of hypoxanthine was observed. From these results, it was concluded that uric acid does exist in the brain, increases after ischemia, and is possibly the end product of purine degradation in the brain. Furthermore, it is suggested that xanthine oxidase exists in the brain and catalyzes the reaction from hypoxanthine to xanthine and then to uric acid. These reactions catalyzed by xanthine oxidase are considered to be a source of free radicals and may play important roles in the pathogenesis of cerebral ischemic injury.

Allopurinol↗
PubMed1989

Purification and partial characterization of a type-specific antigen of Rickettsia tsutsugamushi.

A type-specific antigen (54- to 56-kilodalton polypeptide) in the envelope of Rickettsia tsutsugamushi was purified from each of three prototype strains (Gilliam, Karp, and Kato) by a combination of mild anionic detergent treatment, gel filtration, and reverse-phase high-performance liquid chromatography. The purified antigens from the three strains were shown to have similar amino acid compositions: primarily aspartic acid, glutamic acid, and glycine, with lesser amounts of cysteine, methionine, and tyrosine. The N-terminal amino acid sequences of the antigens were 74.3% homologous among the three strains.

Amino Acid Sequence↗
PubMed1989

Serodiagnosis of scrub typhus with antigens immobilized on nitrocellulose sheet.

This study was designed to develop a simple method for serodiagnosis of scrub typhus. The basis of the method is detection of anti-Rickettsia tsutsugamushi antibody in patient serum by reaction with antigens dot blotted on a nitrocellulose sheet (NCS). The final evaluation of the reaction is performed by observing the color intensity which develops as a result of sequential treatments of the NCS with peroxidase-conjugated anti-human immunoglobulin G or immunoglobulin M antibody and with the substrate of the enzyme. After various trials, we found that the best results were obtained by using a purified antigen which adhered to an NCS at 0.2 to 2 micrograms of protein per dot and a test serum diluted 1,000- to 4,000-fold. Under these conditions, almost all antibody-positive sera showed a distinct color at the dot on the NCS, so that a positive reaction could be distinguished by the naked eye from a negative reaction with antibody-negative sera, which developed only a faint color. A comparison of the results of screening of antibody-positive and -negative sera by this method and the immunofluorescence test showed that both methods produced similar results. From these results, it is concluded that this dot immunoassay can be useful for the serodiagnosis of scrub typhus.

Antibodies, Bacterial↗
PubMed1989

Effects of a new thyrotropin-releasing hormone derivative on behavioral changes after focal cerebral ischemia in rats.

We observed the effects of a new thyrotropin-releasing hormone derivative, YM-14673 (N alpha-[[(S)-4-oxo-2-azetidinyl]carbonyl]-L-histidyl-L-prolinamide dihydrate), on behavioral changes in rats for 3 weeks after focal cerebral ischemia. Under halothane anesthesia, the left middle cerebral artery was occluded via a transretro-orbital approach. YM-14673 was administered just after the operation and once a day for 3 weeks. Neurologic deficits, including hemiplegia and abnormal posture, and disturbance of passive avoidance learning were present in solvent-treated control rats for the entire 3 weeks. YM-14673 at 0.1 or 0.3 mg/kg i.p. or 1 mg/kg p.o. significantly accelerated the recovery of neurologic deficits and ameliorated cognitive disturbance compared with the solvent-treated controls although the drug at 0.1 and 0.3 mg/kg i.p. did not influence the size of the ischemic infarct. YM-14673 mitigated the behavioral disturbances in this model of chronic focal cerebral ischemia. We also discuss the suitability of this model for the evaluation of drugs.

Animals↗
PubMed1989

Effect of cyclooxygenase and lipoxygenase inhibitors on delayed neuronal death in the gerbil hippocampus.

The purpose of our study was to examine whether cyclooxygenase and lipoxygenase inhibitors ameliorate delayed neuronal death in the hippocampal CA1 sector in Mongolian gerbils after 5 minutes of forebrain ischemia. Gerbils were injected intraperitoneally with cyclooxygenase inhibitors piroxicam and flurbiprofen or with lipoxygenase inhibitors AA-861 and BW-755C. Seven days after ischemic insult, the animals were perfusion-fixed, and the neuronal density in the hippocampal CA1 sector was estimated. The average neuronal density in unoperated normal gerbils was 247 +/- 9/mm (mean +/- SEM). In ischemic gerbils with vehicle administration, the average neuronal densities were 13 +/- 2, 14 +/- 2, 13 +/- 2, and 13 +/- 1 for piroxicam, flurbiprofen, AA-861, and BW-755C, respectively. The average neuronal densities in ischemic gerbils treated with 1.5 and 10 mg/kg piroxicam and 1.5 and 10 mg/kg flurbiprofen were 13 +/- 2, 194 +/- 9, 19 +/- 5, and 143 +/- 12, respectively. In ischemic gerbils treated with 15 and 100 mg/kg AA-861 and 30 mg/kg BW-755C, the average neuronal densities were 12 +/- 1, 13 +/- 1, and 14 +/- 2, respectively. At their higher doses, both piroxicam and flurbiprofen significantly (p less than 0.01) ameliorated delayed neuronal death in the hippocampal CA1 sector. Our results suggest that cyclooxygenase products play an important role in the development of delayed neuronal injury after cerebral ischemia.

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz↗
PubMed1989

Effects of a new thyrotropin-releasing hormone analogue administered in rats 1 week after middle cerebral artery occlusion.

We observed the effects of a new thyrotropin-releasing hormone analogue, YM-14673 (N alpha-[[(S)-4-oxo-2-azetidinyl]carbonyl]-L-histidyl-L-prolinamide dihydrate) on behavioral changes in 26 rats subjected to middle cerebral artery occlusion. The administration of 0.1 mg/kg i.p. YM-14673 was started 1 week after occlusion and was repeated daily for 2 weeks. YM-14673 significantly accelerated the recovery of neurologic deficits and ameliorated the disturbance of passive avoidance learning. Thus, YM-14673 improved behavioral response in a model of chronic focal cerebral ischemia. The availability of a chronic middle cerebral artery occlusion model for the evaluation of drugs is also discussed.

Animals↗
PubMed1989

[Inhibitory effect of various traditional Chinese medicines on rabbit platelet phospholipase A2 in vitro and suppressive effect of tôki-syakuyaku-san on increased aggregability in hypercholesterolemic rabbit ex vivo].

The inhibitory mechanism of 6 traditional Chinese medicines on rabbit platelet aggregation in vitro, and the suppressive effect of oral administration of Tôki-syakuyakusan on hyper-aggregability of the platelet from rabbit fed high cholesterol diet for 2 months, were investigated. Collagen-induced aggregation was inhibited by Keisi-bukuryôgan, Kami-syôyô-san, Dai-saiko-tô, Tôki-syakuyaku-san, Hatimi-ziô-gan and Syô-saiko-tô in their lower concentrations than those inhibiting arachidonic acid- and thrombin-induced aggregation. These traditional Chinese medicines inhibited the release of [3H]arachidonic acid from membrane phospholipids by phospholipase A2, in [3H]arachidonic acid-labelled platelets under stimulation with collagen and thrombin in the concentration ranges that inhibited each aggregation. In their higher concentrations to inhibit arachidonic acid-induced aggregation, they suppressed the conversion of arachidonic acid to thromboxane A2 by about 50%. However, they had no effect on diacylglycerol formation induced by thrombin. The oral administration of Tôki-syakuyaku-san depressed the increased aggregability of platelets from rabbit fed high cholesterol diet by 20-40% at the period of 1-2 months of feeding, without affecting plasma and platelet cholesterol level. These results indicate that the traditional Chinese medicines used here have an inhibitory effect on platelet phospholipase A2 activation, rather than on cyclooxygenase, and therefore inhibit platelet activation in vitro and ex vivo.

Animals↗
PubMed1989

Long-term angiographic follow-up results in patients undergoing percutaneous transluminal coronary angioplasty.

Long-term effects following percutaneous transluminal coronary angioplasty (PTCA) were examined using follow-up coronary angiography (CAG) in 49 lesions in cases in which the procedure was considered to be successful. Follow-up CAG was performed 2-5 times (average, 2.7 times) per patient during a period of 1 year to 3 years and 7 months (average, 1 year and 10 months). The luminal diameter of the PTCA sites was expressed as the percentage of the value immediately after the procedure. Narrowing by 10% or more was observed in 17 lesions 3-8 months after PTCA but in only 4 lesions on the final CAG. The luminal diameter of the PTCA site was significantly greater (p less than 0.05) 2 years after PTCA in comparison to the findings after 1 year. These results suggest excellent long-term effects at the PTCA site.

Angioplasty, Balloon, Coronary↗
PubMed1989

[Comparison of in vitro susceptibilities of Rickettsia prowazekii, R. rickettsii, R. sibirica and R. tsutsugamushi to antimicrobial agents].

The in vitro activities of 16 antimicrobial agents against Rickettsia prowazekii (Breinl strain), R. rickettsii (Bitterroot strain), R. sibirica (ATCC No. VR151) and R. tsutsugamushi (Gilliam, Karp, Kato, Shimokoshi, Kawasaki and Kuroki strains) were determined by the cell culture method. Tetracycline, demethylchlortetracycline, doxycycline, minocycline, chloramphenicol, kitasamycin and rifampicin were generally effective (MIC, 0.005-0.78 micrograms/ml) to all strains tested. Quinolones such as norfloxacin, ciprofloxacin and ofloxacin were moderately active, but they were less active against R. tsutsugamushi than other rickettsial species. Penicillins and cephems showed low activity against most of the strains tested, but high concentrations of benzylpenicillin (MIC, 25-50 micrograms/ml) inhibited R. prowazekii, R. rickettsii and R. sibirica. These findings may be applicable for differentiation of species of genus Rickettsia.

Anti-Bacterial Agents↗
PubMed1989

[Two cases of Frey's syndrome].

During the taking of meals, complex symptoms such as perspiration, rubor, and febrile sensation can appear on the skin overlying the temporal area or the parotid gland after the passage of some time after an operation in the parotid area or trauma inflicted to this area. This phenomenon is usually called Frey's syndrome. We recently encountered two cases of this syndrome. The patients were a 16-year-old boy who developed this syndrome following open reduction of the fractured left temporomandibular articular process and a 72-year-old man who developed it following left hemimandibulectomy and left radical neck dissection performed for the treatment of left mandibular gingival cancer. Frey's syndrome is a relatively rare surgery-associated complication. However, it may be advisable to inform the patient of this possibility prior to an operation, because patients may be severely afflicted by heavy perspiration if this syndrome develops over an extensive area.

Adolescent↗
PubMed1989

[A classification of foods by the amount of masticatory action involved].

With a view to classifying foods on the basis of the amount of masticatory action required, an attempt was made to correlate the properties of different foods as shown by mechanical measurements with the amount of masticatory action involved as determined by means of an electromyogram. We obtained the following results: 1) We found an extremely high correlation (r = 0.924) between the amount of masticatory action involved and the mechanical properties of our samples when these were expressed as values given by the formula: log (firmness x cohesiveness x strainess x 10) We refer to this parameter as toughness. 2) We were then able to estimate the amount of activity necessary in actual mastication of various foods from out toughness values and other values obtained through texturometer readings, a procedure which we carried out for 144 types of foods. 3) We were thus able to classify foods into ten levels according to masticatory action. We further feel justified to add masticatory action to our list of classification criteria as set out in an earlier report by the present author and others entitled "A classification of foods by physical properties."

Food↗