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Biomedical subjects

T Sakamoto

Publications and source records attributed to T Sakamoto.

At least 775 records · Page 43Linked to original sources
PubMed1992

Association of patency of the infarct-related coronary artery with plasma levels of plasminogen activator inhibitor activity in acute myocardial infarction.

To examine the fibrinolytic capacity in patients with acute myocardial infarction (AMI), baseline levels of plasma plasminogen activator inhibitor (PAI) activity and tissue-type plasminogen activator (t-PA) antigen were measured in 47 patients with Q-wave AMI who underwent emergent coronary angiography 3.0 +/- 0.2 hours after the symptom onset. They received intracoronary injection of urokinase if their infarct-related arteries were occluded. They were classified into 3 groups according to the patency of the infarct-related artery before and after thrombolytic therapy: the patent group (13 patients), the recanalized group (23 patients) and the occluded group (11 patients). The mean level of plasma PAI activity (IU/ml) was higher in patients with AMI as a whole than in the control group (12.8 +/- 1.6 vs 5.4 +/- 0.5, p less than 0.01). The level was lower in the patent group (3.0 +/- 1.1) and higher in the recanalized (18.6 +/- 2.2) and occluded (10.8 +/- 2.5) groups than in the control group (each p less than 0.01). The level was lower in the occluded than in the recanalized group (p less than 0.01) and 62% of the patients in the occluded group had levels within range of the control group. The mean level of plasma t-PA antigen (ng/ml) was higher in patients with AMI as a whole than in the control group (10.3 +/- 0.8 vs 5.8 +/- 0.3, p less than 0.01). There was no difference in the level among the 3 groups with AMI.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[The role of insulin on renal sodium handling and sympathetic nerve activity in overweight normotensive subjects].

Recently, it was suggested that the role of hyperinsulinemia on the hypertensive mechanism of essential hypertension might be related to renal sodium handling and sympathetic nerve activity, especially in obese hypertensive patients. However, the interrelationship between insulin, obesity, renal sodium metabolism and sympathetic nerve activity in normotensive subjects (NT) still remains unclear. The present study, therefore, was undertaken to clarify the role of insulin on renal sodium handling and sympatho-adrenal function in overweight NT. The study consisted of 24NT, who were divided into two groups of twelve non-obese (NNT) and twelve obese (ONT) subjects. NNT was categorized as a body mass index (BMI) less than, and ONT as a BMI equal to or more than 25kg/m2. In the early morning, after overnight fasting, all subjects remained in a supine state and were examined for renal clearance test. During the two-hour clearance period, mean arterial pressure (MAP), heart rate (HR), endogenous creatinine clearance(CCr), urinary excretion of sodium (UNaV), fractional excretion of sodium (FENa), plasma immunoreactive insulin (IRI), plasma norepinephrine concentration (pNE), and plasma epinephrine concentration (pE) were determined. Although no significant difference was found in age, MAP, HR, pE, CCr or UNaV between the two groups, a significantly higher IRI (p less than 0.05) and lower FENa (p less than 0.05) were observed in ONT than in NNT. There was no significant correlation between IRI and UNaV, FENa or pE in ONT or in NNT. In addition, no significant correlation was shown between FENa and pNE or pE in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Medulla↗
PubMed1992

Effect of Hoe 140, a new bradykinin receptor antagonist, on bradykinin- and platelet-activating factor-induced bronchoconstriction and airway microvascular leakage in guinea pig.

We have investigated the effect of a new bradykinin receptor antagonist, Hoe 140 (D-Arg- Hyp3,Thi5,D-Tic7,Oic8]-bradykinin), on bradykinin- and platelet-activating factor (PAF)-induced bronchoconstriction and airway microvascular leakage in anesthetized guinea pigs. Extravasation of Evans blue dye and lung resistance were measured simultaneously. Both i.v. (15 nmol/kg) and inhaled bradykinin (1 mM, 45 breaths) caused a significant increase in lung resistance and leakage of dye at all airway levels. Hoe 140 (100 nmol/kg i.v.) almost completely inhibited these airway responses induced by bradykinin except for dye extravasation in trachea induced by inhaled bradykinin. Inhaled PAF (3 mM, 30 breaths) significantly increased lung resistance and leakage of due at all airway levels, but Hoe 140 had no effect on these responses. Bradykinin-induced bronchoconstriction and airway microvascular leakage are predominantly mediated by activation of B2 receptor, since Hoe 140 is a B2 receptor antagonist. Bradykinin receptor-mediated mechanisms do not play an important role on inhaled PAF-induced bronchoconstriction and microvascular leakage.

Administration, Inhalation↗
PubMed1992

The human prohibitin gene located on chromosome 17q21 is mutated in sporadic breast cancer.

A gene called "prohibitin" was isolated as a candidate antiproliferating gene in rat liver cells. We have isolated the human homologue of the rat prohibitin gene and mapped it to chromosome 17q12-21 where a gene responsible for hereditary breast cancer was localized. DNA sequence analysis of 2 exons in this gene in 23 sporadic breast cancers, which showed loss of heterozygosity on the long arm of chromosome 17 or developed in patients 35 years old or younger, identified 4 cases of somatic mutation; 2 of these were missense mutations; 1 showed a 2-base deletion resulting in truncation of the gene product due to a frame shift; the other had a C to T transition in an intron adjacent to an intron-exon boundary. These results suggest that this gene may be a tumor suppressor gene and is associated with tumor development and/or progression of at least some breast cancers.

Amino Acid Sequence↗
PubMed1992

Acceleration of the oxygen reaction in CuA-deficient Nitrosomonas europaea cytochrome c oxidase as revealed by the flow-flash measurement.

The oxygen reaction of Nitrosomonas europaea cytochrome c oxidase containing either 2Cu or 1Cu per two heme a molecules was investigated by the flow-flash technique at 20 degrees C. The reaction profiles of the bacterial enzyme were essentially the same as those of bovine heart cytochrome c oxidase, although the rate of the primary oxygen compound formation was much slower. The 1Cu enzyme exhibited higher rates for both primary oxygen compound formation and intramolecular electron transfer than the 2Cu enzyme. This result clearly indicates that CuA is not essential functionally for the oxidation of ferrous heme a moieties, and suggests its structural importance in maintaining the molecular integrity of N. europaea cytochrome oxidase.

Copper↗
PubMed1992

Production of macrophage colony-stimulating factor by adult murine parenchymal liver cells (hepatocytes).

The activity of macrophage colony-stimulating factor (M-CSF) was found in the culture supernatant of mouse parenchymal liver cell fractions in a bone marrow colony-forming assay. The activity of an M-CSF-like substance purified by a four-step procedure was neutralized by goat anti-mouse M-CSF antiserum. M-CSF mRNA was detected in cellular RNA prepared from cultured parenchymal liver cell fractions by Northern blot analysis and also in cultured parenchymal liver cells by in situ hybridization. These results indicate that parenchymal liver cells have the capacity to produce M-CSF. We discuss the role of M-CSF in hematopoiesis, the immune response, and other biological phenomena.

Acrylic Resins↗
PubMed1992

Comparative study of magnetic resonance and CT scan imaging in cases of severe head injury.

The distribution, frequency, and appearance of head injuries were evaluated with MRI and CT in a prospective study of 155 patients with acute (n = 124) and chronic (n = 31) head injuries. MRI was significantly more sensitive than CT in the detection of intraaxial injury at any stage. In severe cases, central structure lesions were detected in approximately 80% of patients. Severity on admission was compatible with MR findings. However it was difficult to decide on neurobehavioural prognosis from initial MRI findings only.

Adolescent↗
PubMed1992

Catecholamine alterations in experimental hydrocephalus.

Experimental hydrocephalus was induced in rats by intracisternal injection of kaolin suspension. The amounts of norepinephrine and dopamine were determined in the whole brain and specific brain regions at 1 week (acute phase) and 4 weeks (chronic phase). The turnover of catecholamine, an index of the activity of catecholamine-containing neurons, was determined by measuring the decrease in catecholamine contents 2 h after intraperitoneal injection of alpha-methyl-p-tyrosine (250 mg/kg), an inhibitor of tyrosine hydroxylase. We observed that the catecholamine contents in kaolin-induced hydrocephalus were not significantly different from control values. Following injection of alpha-methyl-p-tyrosine, there was decrease in levels of catecholamines in both control and hydrocephalic rats. This decrease was, however, significantly less in induced hydrocephalus than in control animals. This result suggested that in hydrocephalus, the activities of norepinephrinergic and dopaminergic neurons are reduced.

Animals↗
PubMed1992

Expanding cranioplasty for craniosynostosis and allied disorders.

For early correction of craniosynostosis in the newborn or in early infancy, strip craniectomy may produce satisfactory results. For late correction, however, more radical cranial reconstruction procedures are essential in order to achieve adequate remodeling of cranial deformities and normalization of intracranial pressure. Craniosynostosis presents various types of cranial deformity, and different procedures for its correction have been reported. Expanding cranioplasty is presented for the increase of cranial volume and immediate correction of the cranial deformity. This cranioplasty can be applied not only for late correction of various types of craniosynostosis but also for other cranial deformities.

Craniosynostoses↗
PubMed1992

The effect of prednisolone on substance P-induced vascular permeability in mice.

The effect of prednisolone on the substance P (SP)-induced vascular permeability increase in male ddY, WBB6 F1(-)+/+ (control) and WBB6 F1-W/WV (no mast cell in skin or internal organs) mice was investigated. 1) SP (1-10,000 pg/site) increased vascular permeability in ddY, WBB6 F1(-)+/+ and WBB6 F1-W/WV mice ears. 2) SP (100 pg/site)-induced vascular permeability was inhibited by prednisolone (10 mg/kg) administered intraperitoneally 3 to 12 hours prior to the elicitation of the reaction in ddY mice. When dexamethasone at a dose of 1 mg/kg was administered intraperitoneally 2 to 24 hours prior to the elicitation of the reaction, significant inhibition was observed. When prednisolone was administered intraperitoneally 8 hours prior to the elicitation of the reaction, the SP-induced capillary permeability increase in both ddY and WBB6 F1-W/WV mice was clearly inhibited by the drug at doses of 5 and 10 mg/kg. 3) Diphenhydramine (1 and 10 mg/kg) inhibited SP-induced vascular reaction in ddY mice but not in WBB6 F1-W/WV mice. 4) Atropine (10 mg/kg) inhibited SP-induced vascular reaction in both ddY and WBB6 F1-W/WV mice. But acetylcholine did not cause an increase of vascular permeability in ddY and WBB6 F1-W/WV mice ears. 5) Prednisolone (5 mg/kg) inhibited histamine- and serotonin-induced vascular permeability in ddY and WBB6 F1-W/WV mice ears. 6) Prednisolone (5 and 10 mg/kg) inhibited the SP-induced histamine release from ddY mice peritoneal mast cells. These results suggest that the vascular effect of SP is mediated by both mast cell dependent (release of histamine from mast cells) and mast cell independent mechanisms. Prednisolone inhibits the SP-induced vascular permeability mediated by both mechanisms in mice.

Animals↗
PubMed1992

Some considerations on the biology of pancreatic serous cystadenoma.

Five cases of pancreatic serous cystadenoma were examined pathologically, and their nuclear DNA ploidy patterns were determined. Four were unifocal tumors, and one was a multifocal tumor. The four unifocal tumors were typical serous cystadenomas. However, the multifocal tumor exhibited an increased N/C ratio, irregular nuclear margins, various-sized nuclei, coarse nuclear chromatin, and neural invasion. All tumor cells were stained with antiCA19-9 but none with antiCEA. In the antiCA19-9 staining, the four unifocal tumors and the tumors of the pancreatic tail in the multifocal case were positive only on the apical membrane, whereas the tumor cells of the pancreatic head in the multifocal case were positive within the whole cytosol. The unifocal tumors were diploid with a DNA Index (DI) of 1.0 and proliferation indices (PI) from 4.9 to 20.9% with a mean of 14.4%. In the multifocal case, the tumor in the pancreatic head was aneuploid (DI = 1.9) and had a PI of 27.8%. The multifocal sites in the pancreatic body were aneuploid (DI = 1.9) with a PI of 22.4%. We suggest that the biological property of serous cystadenoma should be revisited.

Aged↗
PubMed1992

Plasma plasminogen activator inhibitor activity and tissue plasminogen activator levels in patients with unstable angina and those with coronary spastic angina.

Plasminogen activator inhibitor (PAI) activity and tissue plasminogen activator (TPA) antigen were measured in venous samples in 14 patients with unstable angina consisting of eight patients with organic stenosed coronary arteries and six patients with coronary spastic angina (unstable angina group); in 14 patients with stable exertional angina (stable exertional angina group); and in 14 patients with chest pain syndrome (chest pain syndrome group). The plasma levels of PAI activity were higher (p less than 0.01) in the unstable angina group than in the stable exertional angina group and the chest pain syndrome group (12.3 +/- 1.0 versus 5.1 +/- 0.7 and 4.8 +/- 0.6 IU/ml). The plasma levels of TPA antigen were also higher (p less than 0.05) in the unstable angina group than in the stable exertional angina group and the chest pain syndrome group (10.2 +/- 1.3 versus 6.5 +/- 0.8 and 6.0 +/- 0.7 ng/ml). There were no significant differences in PAI activity and TPA antigen levels between the stable exertional angina group and the chest pain syndrome group. Furthermore, both PAI activity and TPA antigen levels in the unstable angina group decreased to the levels in the stable exertional angina group and the chest pain syndrome group after treatment (p less than 0.01). In conclusion, the increased plasma PAI activity in patients with unstable angina and in those with coronary spastic angina indicates that the fibrinolytic system is impaired in these patients.

Angina, Unstable↗
PubMed1992

Effects of intraaortic balloon position on renal artery blood flow.

Debate continues over what happens to renal blood flow when intraaortic balloons are adjacent to the renal arteries. Fourteen dogs were prepared by implanting instruments to measure heart rate; right atrial, pulmonary arterial, carotid arterial, and femoral arterial pressures; cardiac index; mixed venous oxygen saturation; urine output; and left and right renal blood flows. A 12-mL intraaortic balloon was inserted through the left (n = 9) or right (n = 5) femoral artery. The position of the balloon was randomized so that it was initially placed in either the control (thoracic) or renal position (at the level of the renal arteries). Intraaortic balloon pumping was performed for 4 hours in each position. In 8 dogs, at least one of the renal arteries had partial occlusion, 23% to 98% decrease in flow (mean decrease, 66%), while the intraaortic balloon was in the renal position. An intraaortic balloon in the renal position results in lower renal blood flow as well as a high risk (57%) of selective renal artery occlusion. Decreased renal blood flow is not apparent using conventional monitoring, as hemodynamics do not change.

Animals↗
PubMed1992

Growth hormone (GH)-dependent hepatic GH receptors in the Japanese eel, Anguilla japonica: effects of hypophysectomy and GH injection.

Control mechanisms of growth hormone (GH) receptors in the eel liver were examined by following the time course of changes in total (MgCl2-treated membranes) and free (untreated membranes) GH-binding sites after hypophysectomy and replacement therapy with homologous GH. Both total and free binding sites decreased significantly 1 week after hypophysectomy. Scatchard analysis indicated that the reduction in GH receptors was primarily due to a decrease in the number of binding sites, rather than to a change in binding affinity. When recombinant eel GH was injected intramuscularly into hypophysectomized eels (2 micrograms/g body wt), plasma GH concentration increased to a maximal value after 10 hr and decreased to the initial level by 72 hr. Free binding sites decreased to a minimal value 24 hr after the injection and returned to the initial level after 72 hr. The reduction in free binding sites seems to be due to occupation of GH receptors. Total binding sites increased gradually to almost twofold over those of the controls 5 days after the injection, the increase being due to an increase in the binding capacity. GH appears to be importantly involved in inducing and maintaining its own receptors in the eel liver.

Analysis of Variance↗
PubMed1992

Treatment of sleep apnea with prosthetic mandibular advancement (PMA).

Nine males with sleep apnea DOES syndrome and three males with sleep apnea DIMS syndrome were treated with prosthetic mandibular advancement (PMA). The method uses a prosthesis, which is designed to advance the mandible 3-5 mm to prevent upper airway occlusion during sleep. The apnea index in the obstructive-type apnea and the percentage of time spent in obstructive apnea decreased significantly with PMA. Although the apnea index showed merely a tendency to decrease in central apnea (p < 0.1), the percentage of time spent in central apnea decreased significantly with PMA. A marked improvement in sleep structures was observed with PMA; a significant increase was seen in total sleep time, percent slow wave sleep (SWS) and percent rapid eye movement (REM) sleep, and the time spent in intra-sleep awakening decreased remarkably. PMA had excellent effects on snoring, and daytime hypersomnolence was reduced in almost all patients. Moreover, a survey on the therapeutic effects of PMA on sleep apnea syndrome and problems associated with wearing PMA was performed with a questionnaire for the sample of nine DOES patients and an additional 22 patients who were treated over a long time. The therapeutic effects could be maintained without any problems in about 2/3 of these patients. The therapeutic mechanisms of PMA in its reduction of both obstructive and central apnea are discussed.

Adult↗
PubMed1992

Tsutsugamushi disease in the central part of Japan.

Two cases of tsutsugamushi disease misdiagnosed initially as drug eruption were reported. Clinical symptoms of both cases disappeared dramatically after starting minocycline. Statistical examinations were performed on 29 cases of tsutsugamushi disease, including those observed in Mie Prefecture since 1982. Half of them were seen in the last 2 years. The onset was predominantly recorded in November (59%). Presumptive sites of infection were forests (63%) and fields (21%). No patients were infected along river-banks.

Adult↗
PubMed1992

Fc epsilon receptor II/CD23+ lymphocytes in atopic dermatitis. III. Aberrant control in the in vitro expression of Fc epsilon RII/CD23 on peripheral blood T cells in atopic dermatitis.

In vitro Fc epsilon RII expression was examined in patients with atopic dermatitis, those with non-atopic eczematous dermatitis and normal individuals following stimulation of peripheral blood cells with recombinant IL-4 (rIL-4), phytohaemagglutinin (PHA), or PHA plus rIL-2. At various days cells were stained with MoAbs to human lymphocyte Fc epsilon RII and to lymphoid cell-surface antigens and analysed by flow cytometry. rIL-4, but not rIL-2, specifically induced Fc epsilon RII on T cells as well as B cells in atopic dermatitis, eczematous dermatitis and normal individual groups. Both atopics and non-atopics generated comparable proportions of Fc epsilon RII+ T cells (T epsilon cells), whereas the frequency of B cells bearing Fc epsilon RII(B epsilon cells) was significantly higher in patients with extensive atopic dermatitis than in those with mild atopic dermatitis and other subjects. Comparable levels of T epsilon cells were detected in both atopic and non-atopic donors following stimulation of peripheral blood cells with PHA or pre-activation of the cells with PHA plus subsequent incubation with rIL-2. Whereas both CD8+ and CD4+ subsets were present in T epsilon cell populations induced specifically by rIL-4, PHA and PHA plus rIL-2, patients with atopic dermatitis had a greater tendency for Fc epsilon RII expression on CD8+ T cells compared with patients with eczematous dermatitis and normal individuals. Recombinant interferon-gamma (rIFN-gamma), but not rIFN-alpha or prostaglandin E2 (PGE2), suppressed the generation of T epsilon cells by rIL-4 in atopics and non-atopics to the same degree. These results suggest the aberrant control of Fc epsilon RII expression on T cells, especially those bearing CD8, in atopic dermatitis.

Adolescent↗