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Biomedical subjects

M Takenaga

Publications and source records attributed to M Takenaga.

At least 55 records · Page 3Linked to original sources
PubMed1987

In vitro effect of cinnamic aldehyde, a main component of Cinnamomi Cortex, on human platelet aggregation and arachidonic acid metabolism.

The in vitro effect of cinnamic aldehyde, a main component of Cinnamomi Cortex, on platelet aggregation and arachidonic acid (AA) metabolism in human platelets was studied. Cinnamic aldehyde reduced platelet aggregation of both platelet rich plasma and washed platelets, dose-dependently. This compound also decreased the formation of the metabolites of AA such as thromboxane B2 (TXB2), 12-hydroxy heptadecatrienoic acid and 12-hydroxyeicosatetraenoic acid in collagen-stimulated washed platelets. The conversion of exogenous [14C]AA to cyclooxygenase metabolites or 12-lipoxygenase metabolite was not altered significantly by the addition of cinnamic aldehyde. On the other hand, collagen-induced release of [14C]AA and its metabolites from washed platelets prelabeled with [14C]AA was markedly reduced by the addition of cinnamic aldehyde. These results suggested that cinnamic aldehyde suppressed the release of AA from platelet membrane phospholipids and then reduced the formation of thromboxane A2. This inhibitory effect of cinnamic aldehyde on AA release and TXB2 formation may contribute to reduced platelet aggregation.

Acrolein↗
PubMed1987

Anti-thrombotic and anti-atherogenic action of eicosapentaenoic acid.

Effects of dietary supplementation with highly purified EPA (1.8-2.7 g/day) for 16 weeks on platelet and red blood cell function and serum lipids concentration were investigated in patients with various thrombotic diseases. Decreases in platelet aggregation, thromboxane formation in platelets, platelet retention and whole blood viscosity, increased red blood cell deformation and prolongation of bleeding time were observed in the present study. In addition a reduction in serum cholesterol and triglyceride concentrations was noted in patients with hyperlipidemia after EPA ingestion. Some clinical improvements such as improvement of diabetic gangrene or peripheral vascular occlusive disease were observed. These results indicate that dietary supplementation of purified EPA may be beneficial for prevention and treatment of cerebro- and cardiovascular diseases.

Arteriosclerosis↗
PubMed1987

Surface marker studies on activated peripheral blood lymphocytes in idiopathic dilated cardiomyopathy.

Expression of interleukin 2 (IL-2) receptor on peripheral blood lymphocytes after stimulation with concanavalin A (Con A) or anti-T3 monoclonal antibody was analyzed in patients with dilated cardiomyopathy (DCM) in order to clarify the abnormalities of lymphocyte activation mechanism in DCM. The expression of IL-2 receptor after the stimulation with either Con A or anti-T3 monoclonal antibody was found to be reduced in the patients with DCM when the results were compared with those of controls. A significant correlation was noticed between the expression of IL-2 receptor after Con A stimulation and T4+/T8+ cell ratio, and between the expression of IL-2 receptor after anti-T3 monoclonal antibody stimulation and the left ventricular end-diastolic pressure (LVEDP). The results suggest that there are abnormalities of lymphocyte activation in DCM and that the alteration may be associated with the cause or clinical conditions of DCM.

Adult↗
PubMed1986

Comparison of the in vitro effect of eicosapentaenoic acid (EPA)-derived lipoxygenase metabolites on human platelet function with those of arachidonic acid.

Eicosapentaenoic acid (EPA) has been reported to have a potent anti-aggregatory activity and to be efficiently metabolized by 12-lipoxygenase, not by cyclooxygenase in platelets. In vitro effect of 12-lipoxygenase metabolites of EPA on platelet function was studied and compared with those of arachidonic acid (AA). The 12-lipoxygenase metabolites of AA and EPA; 12-hydroperoxyeicosatetraenoic acid (12-HPETE) and 12-hydroperoxyeicosapentaenoic acid (12-HPEPE), and their hydroxy derivatives, 12-hydroxyeicosatetraenoic acid (12-HETE) and 12-hydroxyeicosapentaenoic acid (12-HEPE) were prepared enzymatically using human platelet lysate. These compounds were purified by high performance liquid chromatography and identified by gas chromatography mass spectrometry. 12-HPETE and 12-HPEPE inhibited dose-dependently washed human platelet aggregation and serotonin (5-HT) release induced by AA and collagen. The potency of 12-HPEPE was almost equal to that of 12-HPETE. Their hydroxy derivatives, 12-HETE and 12-HEPE were less potent. 12-hydroperoxy derivatives of AA and EPA were the most potent in inhibiting platelet aggregation and 5-HT release among 5-, 12- and 15-hydroperoxy isomers of AA and EPA. The inhibitory effects of 12-HPETE and 12-HPEPE on platelet aggregation were additive.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1986

Clinical and epidemiological studies of eicosapentaenoic acid (EPA) in Japan.

From 1950 to 1980, the gross alteration in dietary habit in Japan was noted. Intake of total calories has markedly increased. This could be most likely due to a remarkable increase in intake of fat, especially animal fat, egg and milk products. A marked decrease of mortality rate due to cerebral hemorrhage and in contrast a marked increase of mortality rate due to cerebral infarction and ischemic heart disease were noted. An epidemiological study of the intake of fish meat (EPA intake) and the mortality rate of adult diseases was performed in a fishing area and in a farming area in Chiba Prefecture. Intake of fish meat (EPA) by the residents of the fishing area was 2-3 times higher than by the residents of the farming area. The mortality rate due to ischemic heart disease and cerebral vascular diseases tended to be lower in the fishing area than in the farming area. EPA manufactured from sardine oil was orally given to normal subjects and to patients with cerebro- and cardiovascular diseases for 4-16 weeks. Significantly decreased platelet aggregation, decreased platelet retention, lowered whole blood viscosity, prolonged bleeding time, increased erythrocyte deformability, improvement of hyperlipidemia, and clinical improvement in some patients were noted. 12-Lipoxygenase metabolites of EPA (12-HPEPE) and arachidonic acid (12-HPETE) have an equipotent inhibitory action on platelet function.

Arachidonate 12-Lipoxygenase↗
PubMed1986

[Mitral regurgitation due to abnormal reinsertion of chordae tendineae (looping) of the posterior mitral leaflet: clinical and echocardiographic features].

Two-dimensional (2D) echocardiographic and clinical characteristics of patients with mitral regurgitation (MR) due to abnormal reinsertion of chordae tendineae (looping) in the middle scallop of the posterior leaflet were described and compared with those of patients with chordal rupture of the posterior leaflet. Twenty-five patients with posterior mitral valve prolapse who underwent mitral valve replacement were studied. They were categorized in three groups; 14 patients with MR due to ruptured chordae tendineae (RCT) of the posterior leaflet (RCT group); three patients with looping of the chordae tendineae in the middle scallop of the posterior leaflet (looping group); and eight patients with both RCT and looping (looping + RCT group). It was difficult to distinguish the looping group from the other two groups by their 2D echocardiographic findings, which were characteristic of those of RCT. However, the following findings were more frequently encountered in the patients with looping than in those without: 1) aberrant or absent systolic coaptation with salient arc of the posterior leaflet, observed in six of the RCT group (43%), two in the looping group (67%) and seven in the looping + RCT group (88%); 2) with thickened edges of the posterior leaflet, shown in three of the RCT group (21%), two of the looping group (67%) and five of the looping + RCT group (63%) in the long-axis view, and also noticed in four of the RCT group (29%), two of the looping group (67%) and six of the looping + RCT group (75%) in the short-axis view. In the clinical history, the onset of a heart murmur, congestive heart failure and surgical treatment occurred at significantly younger ages in the looping group than in the RCT group. As for hemodynamic parameters, pulmonary hypertension was significantly milder in the looping group than in the RCT group. In conclusion, although 2D echocardiographic findings of patients with looping were similar to those of patients with RCT, it seemed possible to differentiate the looping group from the RCT group by the 2D finding of a prolapsed posterior mitral valve with a salient arc and a thickened edge. It was also suggested that the looping of chordae tendineae in the middle scallop of the posterior leaflet was congenital in origin.

Adolescent↗
PubMed1986

[Metastatic thyroid cancer to the right ventricle causing obstruction of the right ventricular outflow tract and associated with disseminated intravascular coagulopathy: a case report].

A case of thyroid cancer causing right ventricular outflow tract obstruction is described. A 72-year-old woman was admitted because of shortness of breath, some ecchymoses, and marked anasarca. Her liver was palpable four fingerbreadths below her costal margin. Laboratory findings included leukocytosis, marked thrombocytopenia, and an increase in fibrinogen degradation products due to disseminated intravascular coagulopathy. Two-dimensional echocardiography demonstrated a solid mass in the right ventricle, which protruded into the right atrium and main pulmonary artery. Right ventricular outflow tract obstruction and tricuspid regurgitation were demonstrated by contrast echocardiography. These findings were confirmed by CT scans, RI angiography, and contrast angiography. The mass was partially resected from her right ventricle and her tricuspid valve was replaced successfully, but she died of sepsis three weeks after surgery. At autopsy, undifferentiated thyroid cancer and cardiac metastasis were verified. To date, only eight cases with initial symptoms of congestive heart failure due to right ventricular outflow tract obstruction caused by metastatic intracavitary tumors have been reported. Very rarely have cardiac tumors resulted in disseminated intravascular coagulopathy.

Aged↗
PubMed1986

[Mitral regurgitation due to ruptured chordae tendineae: sensitivity and specificity of the diagnostic criteria by two-dimensional echocardiography].

The sensitivity and specificity of the two-dimensional (2D) echocardiographic criteria for diagnosing ruptured mitral chordae tendineae (RCT) were assessed in 52 cases with non-rheumatic mitral regurgitation undergoing mitral valve prostheses. At surgery, chordal rupture was confirmed in 38 cases (RCT group), but not in 14 cases (non-RCT group). Four presumptive and three definite findings for diagnosing mitral chordal rupture using 2D echo were evaluated. Mitral valve prolapse with incomplete coaptation of the mitral leaflets in the long-axis view was observed in 32 cases in the RCT group and in four cases in the non-RCT group (sensitivity 84%, specificity 80%). In the short-axis view at the level of the mitral orifice, delayed closure of the involved mitral leaflet was observed in four cases in the RCT group but in none of the non-RCT group (sensitivity 11%, specificity 100%), delayed protodiastolic opening of the involved leaflet in 15 cases of the RCT group and in one of the non-RCT group (sensitivity 39%, specificity 92%), and finally, increased excursion of the involved valve in 27 cases of the RCT group and in three cases of the non-RCT group (sensitivity 71%, specificity 79%). The following three echocardiographic findings were regarded as direct evidence of mitral chordal rupture: Fine echoes with abnormally rapid transverse and/or oblique motion around the mitral orifice in the short-axis view were observed in 13 cases of the RCT group (sensitivity 34%, specificity 100%); echoes with abnormal whip-like motion in the long-axis view in 10 cases (sensitivity 26%, specificity 100%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Mechanism of anti-platelet aggregating action of dilazep.

In vitro effect of Dilazep on the release and metabolism of arachidonic acid (AA) in human platelets was studied. Dilazep reduced in a dose-dependent manner platelet aggregation and thromboxane B2 (TXB2) formation when stimulated by adenosine diphosphate, collagen and epinephrine. Dilazep decreased thrombin-induced release of [14C]arachidonic acid ([14C]AA) from platelets prelabeled with [14C]AA. The conversion of [14C]AA to cyclooxygenase metabolites was reduced by the addition of Dilazep, while that to 12-lipoxygenase metabolite was rather increased. Adenosine 3',5'-cyclic monophosphate and guanosine 3',5'-cyclic monophosphate levels in washed human platelets were not affected by the addition of Dilazep. These results suggest that the decreased TXB2 formation by Dilazep may be ascribed to the impairment of AA release from platelet membrane phospholipids and the reduced conversion of released AA to TXA2.

Adenosine Diphosphate↗
PubMed1983

A new phosphor Li2B4O7: Cu for TLD.

The phosphor Li2B4O7: Cu (0.03% by weight) has an effective atomic number of 7.3, which is very similar to that of tissue (7.4). This suggests that the phosphor should have excellent properties for thermoluminescent dosimetry. The phosphor prepared by a sintering method shows two glow peaks composed of a dosimetric peak at 205 degrees C and a shoulder at 120 degrees C, and a broad emission band peaking at 368 nm. The material based on the stoichiometric compound of Li2O . 2B2O3 has a good moisture resistant property. The dosimetric characteristics are as follows: (1) The sensitivity of gamma rays is about 20 times higher than that of Li2B4O2: Mn prepared by the conventional melting method. (2) The dosimetry peak of 205 degrees C fades less than 9% in intensity at 25 degrees C after 60 days in dark. (3) The TL output is linear with exposure to about 10(5) R, becoming sublinear above it. (4) The sensitivity loss caused by humidity is about 10-25% after 2-6 months of storage in air of 90% relative humidity at 25 degrees C. (5) The energy dependence of TL output for photons is flat within the limit of 10% from 40 keV to 7 MeV. (6) The light induced fading is 10% after 3 h room lighting at 1000 lux.

Borates↗
PubMed1982

Construction of a composite thin-element TLD using an optical-heating method.

A composite thermoluminescent dosimeter (TLD), composed of four, thin TL elements with a high-speed reader, has been developed by employing an optical-heating method. Each TL element, which is 15 mg/cm2 thick with a 3 mm dia., is prepared by applying Li2B4O7:Cu or CaSO4:Tm to a plastic substrate 14 mg/cm2 thick. Each element can be heated to 350 degree C within 0.8 sec. by IR radiation from a tungsten lamp. The characteristics of this TLD system include the following: (1) the detection limit of the Li2B4O7:Cu is 3 mR and the limit for CaSO4:Tm is 0.1 mR; (2) the energy-dependence curves are similar to the dose-equivalent curve, showing slight under-responses by 15% near 70 KeV for Li2B4O7:Cu and over-responses by 50% at high energies for CaSO4:Tm; (3) despite quick heating, the residual dose is as low as 0.1% of the last exposure signal; (4) responses are very stable for more than 1,000 cycles of repeated exposure readings; (5) no false signal could be detected, even in the cases of sweat or soil contamination; (6) the thin Li2B4O7;Cu element can be used for skin dose monitoring; and (7) the processing time of the automatic reader for the composite dosimeter is 3 hr/500 dosimeters. This TLD system can be applied to personnel dosimetry, gate monitoring and environmental monitoring.

Borates↗
PubMed1982

Determination of dihydroergot alkaloids in serum by radioimmunoassay.

A radioimmunoassay for dihydroergotoxine was developed using antiserum frm the rabbit injected with a dihydromethylergometrine-bovine serum albumin conjugate. The antiserum was found to be highly specific to dihydroergot alkaloids. The minimum detectable amount of dihydroergotoxine methanesulfonate with this assay system was about 100 pg/ml in serum. Practical applicability of the assay system was proved by measuring dog serum concentrations after oral administration of dihydroergotoxine methanesulfonate.

Administration, Oral↗
PubMed1980

Microassay of gamma-glutamyl transpeptidase in needle biopsies of human liver.

A method is described for determination of liver gamma-GTP activity in homogenates of the small amount of human liver tissues (approx. 5--7 mg wet wt.) obtained by needle biopsy. The gamma-GTP activity in the liver of healthy subject was < 20 mU/mg protein. The microdetermination of gamma-GTP described here is worth in the diagnosis of hepatic injury, especially alcoholic hepatitis and drug-induced liver diseases.

Aniline Compounds↗