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Biomedical subjects

T Yaginuma

Publications and source records attributed to T Yaginuma.

At least 73 records · Page 4Linked to original sources
PubMed1990

Mitogenic action of interleukin-1 alpha on vascular smooth muscle cells mediated by PDGF.

We have investigated the effect of interleukin-1 (IL-1) on the growth of vascular smooth muscle cells (VSMC) isolated from rat aortae. Murine recombinant IL-1 alpha increased tritiated leucine incorporation into VSMC. IL-1 also stimulated tritiated thymidine uptake by VSMC in a dose-dependent manner. On the other hand, Ca2(+)-channel blocker, verapamil, inhibited the IL-1-induced thymidine uptake by VSMC with an IC50 of 10(-8) M. Antibody specific for platelet-derived growth factor (PDGF) also totally inhibited the IL-1-induced thymidine uptake. IL-1 showed no effects on the intracellular Ca2+ level in VSMC. Above results support the premise that IL-1 promotes the growth of VSMC via induction of endogenous PDGF production and might thus participate in the abnormal proliferation of VSMC that occurs early in atherogenesis.

Animals↗
PubMed1990

Ventricular cells in culture from adult spontaneously hypertensive rats exhibit decreased growth.

We have investigated the growth characteristics of adult rat ventricular cells (ARVC) in culture from 8-week-old spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). Protein synthesis in ARVC estimated from tritiated leucine uptake was augmented in both strains after exposure of cells to either norepinephrine or fetal bovine serum (FBS), but the response was significantly smaller in SHR than in WKY. A relative increase in the protein content of ARVC incubated with norepinephrine or FBS was also smaller in SHR than in WKY. These results demonstrate that SHR cardiac myocytes are not genetically growth-accelerated and show a decreased growth response to growth stimuli such as norepinephrine and serum during the adult period.

Aging↗
PubMed1990

The relevance of psychosocial factors in acute ischemic heart disease. A case-control study of a Japanese population.

We investigated, by case-control study, the relevance of psychosocial factors on the prevalence of acute ischemic heart disease (IHD) in middle aged Japanese men. We questioned 109 acute IHD patients and 80 individuals in an age-adjusted sampled control group. Multiple logistic regression analysis showed the following statistically significant factors: hypertension (odds ratio 4.01, p less than 0.001), Type A behavior pattern (2.25, p less than 0.05) and high job demand (2.23, p less than 0.02). No direct influence of family function or social support to the prevalence of acute IHD was apparent. These results suggest that, among men in Japan, Type A behavior pattern and high job demand represent psychosocial risk factors of IHD. Due to the case-control protocol, causal relationships cannot be decided. The limitation of the study design is discussed within that context.

Coronary Disease↗
PubMed1990

Hyponatremia and hyperreninemic hypoaldosteronism in a critically ill patient: combination of insensitivity to angiotensin II and tubular unresponsiveness to mineralocorticoid.

A 62-year-old man with pneumonia and left flank pain had a clinical syndrome of hyponatremia, hypotension, dehydration, and high urinary sodium excretion in the presence of a normal glomerular filtration rate. The plasma level of antidiuretic hormone was relatively high despite decreased serum osmolality. Thyroid function and excretion of glucocorticoid and sex steroids were normal. The serum aldosterone level was very low despite elevated plasma renin activity. Angiotensin II failed to stimulate any secretion of aldosterone, despite the occurrence of a progressive rise in blood pressure. On the other hand, rapid ACTH administration increased both serum aldosterone and cortisol. The patient showed no effective response to increased salt intake, but large doses of mineralocorticoid resulted in a normal serum sodium level without dehydration. Subsequently, he suffered cardiac arrest secondary to ventricular tachycardia. Postmortem examination showed well differentiated adenocarcinoma in the left pleura and an intact, histologically normal adrenal zona glomerulosa and kidney. This is the first reported case of a critically ill patient with hyponatremia caused by hyperreninemic hypoaldosteronism possibly due to angiotensin II insensitivity and tubular unresponsiveness to mineralocorticoid.

Adrenal Glands↗
PubMed1989

20-Hydroxyecdysone acts in the male pupa to commit accessory glands toward trehalase production in the adult mealworm beetle (Tenebrio molitor).

During postecdysial adult maturation, the bean-shaped accessory reproductive glands (BAGs) of adult male mealworm beetles produce increasing amounts of trehalase. In order to determine when the BAGs become competent to produce trehalase, we transplanted pupal BAGs into 0-day female adults. After 8 days, trehalase activity had increased in BAGs from 4- and 5-day pupae (at the time of the pupal ecdysteroid peak) but not in those from 1- and 2-day pupae (before the ecdysteroid peak). BAGs from 0- and 2-day pupae were exposed to 20-hydroxyecdysone in vitro before implantation into 0-day female adults. Increase in trehalase activity was dose dependent. Both dose (ED50, 5 x 10(-6) M) and exposure time (greater than 6 hr) of hormone required are greater for commitment than for acceleration of pupal cell cycling (T. Yaginuma, H. Kai, and G.M. Happ, 1988, Dev. Biol. 126, 173-181). Since trehalase activity increased markedly in isolated adult male abdomens, factors from the cephalic and thoracic centers are not required to sustain trehalase production in the adult BAGs.

Abdomen↗
PubMed1989

Preventive effect of traditional herbal medicine, shosaiko-to, on danazol-induced hepatic damage.

The incidence of the hepatic damage during treatment with danazol (D), indicated by increased serum GOT, GPT and LDH levels, has been shown to be high especially in Japan. Thus, the preventive effect of the traditional herbal medicine, shosaiko-to (SS) was investigated in the administration of D and SS for 16 weeks (D + SS group, N = 9) and the pre-administration of SS for about 4 weeks followed by D and SS for 16 weeks (SS----D + SS group, N = 15). The incidence of serum GOT, GPT and LDH levels of more than normal range during the administration of danazol in the D + SS group was similar to that in the previous study of the administration of D alone. But it was significantly lower in the SS----D + SS group than the D + SS group. The mean levels of serum GOT and GPT were much lower in the SS----D + SS group than the D + SS group throughout the administration of danazol and the difference was significant at 8, 10 and 12 weeks in serum GOT levels and at 4 weeks in serum GPT levels. These results indicate that the pre-administration of SS has great efficacy in the prevention of danazol-induced hepatic damage.

Adult↗
PubMed1989

Effect of traditional herbal medicine, shakuyaku-kanzo-to on total and free serum testosterone levels.

The effect of the traditional herbal medicine, Shakuyaku-Kanzo-To (SK), which contains Shakuyaku (S) and Kanzo (K) in equal amounts, on serum testosterone levels was investigated in androgen-sterilized rats. They were given orally SK [0, 22.5, 45, 90 and 180 mg/kg body weight (b.w.)] and S or K (0, 11.25, 22.5, 40 and 90 mg/kg b.w.) in 2 ml of water daily for 2 weeks. Dose-dependent decreases in free serum testosterone (T) levels were found in the administration of SK. Total serum T levels in the administration of SK and S decreased in a dose-dependent manner. K decreased total serum T levels slightly in 11.5 and 22.5 mg/kg doses but showed the dose-dependent increase in much higher doses, the extent of which was much less than that of the decrease in S. Serum estradiol/T (E2/T) ratios were significantly elevated in 45 to 180 mg/kg doses of SK, 90 mg/kg dose of S and 11.25 to 90 mg/kg doses of K. Serum LH and FSH levels were not changed by SK, S and K. Oophorectomized rats were similarly given SK (0, 90 and 180 mg/kg b.w.) and S or K (the half doses of SK). There were no changes in serum T, LH and FSH levels in all given doses. Thus, one of the mechanisms for SK to lower serum T levels is the direct action on the ovary to stimulate the aromatase activity, resulting in decreasing the T secretion and this is the additive effects of S and K.

Animals↗
PubMed1989

The development and reversal of tolerance to antianginal effect of isosorbide dinitrate in patients with effort angina.

The development and reversal of tolerance to the hemodynamic and anti-anginal effects of isosorbide dinitrate in a sustained release form (ISDN-SR) were investigated in 11 male patients (mean age 58.9 y.o.) with stable effort angina. Treadmill exercise test, evaluation of hemodynamic parameters and measurement of plasma ISDN concentrations were performed during the control period, on the 1st, 7th and 14th days of therapy with 40 mg of ISDN-SR orally every 8 h and, subsequently, on the day when ISDN-SR was re-administered after a 72 h placebo period (17th day). Initially, exercise tolerance time (ETT) was prolonged significantly (p less than 0.001) by ISDN-SR from 257 +/- 50 sec in the control period to 434 +/- 55 sec on day 1. This prolongation was significantly reduced with sustained therapy and ETT was shortened to 332 +/- 69 sec on the 7th day (p less than 0.01 vs day 1) and 326 +/- 73 sec on the 14th day (p less than 0.01 vs day 1). The effects of ISDN-SR initially observed were restored after a 72 h placebo period and ETT was prolonged to 432 +/- 57 sec on the 17th day. The resting heart rate was increased significantly (p less than 0.01 vs control) and systolic blood pressure was decreased (p less than 0.001 vs control) by ISDN-SR on day 1. These changes were also diminished significantly (p less than 0.01 vs day 1) with sustained therapy and were restored after a 72 h nitrate-free interval.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1989

Mechanical adaptation of heart rate change for coronary circulation in patients with and without ventricular hypertrophy.

To clarify the mechanical adaptation and interference of coronary vessels, we studied hemodynamics of coronary circulation in control and 4 different pacing rates (80, 100, 120, 150/min) in 5 patients with angina pectoris (AP) and in 5 patients with hypertrophic cardiomyopathy (HCM). Coronary sinus flow (CSF) was measured by a Webster's thermodilution catheter, and we applied ascorbic acid-platinum reaction for the mean transit time measurement in left coronary flow (t0-t2). Coronary vascular bed (CVB) was obtained by multiplying CSF and t0-t2. CSF in AP gradually increased from 104 +/- 21 ml/min at 72/min to 148 +/- 42 ml/min at 120/min, while CSF in HCM changed slightly from 91 +/- 25 ml/min at 64/min to 94 ml/min at 120/min. Average t0-t2 in HCM was 6.0 +/- 1.6 sec in control which was significantly lower than that in AP (7.8 +/- 0.7 sec). Calculated CVB in AP increased at any given heart rate up to 120/min (13.5 +/- 2.4, 15.8 +/- 1.7, 15.0 +/- 4.7, 15.1 +/- 4.3 ml), but CVB in HCM decreased from 9.1 +/- 2.3 ml at 64/min to 8.1 +/- 1.7 ml at 120/min. These data suggest that myocardial compression and suction at different heart rates and with different cardiac muscle structures play an important role for beat to beat adjustment of coronary circulation in cardiac cycle.

Adaptation, Physiological↗
PubMed1989

[Mass screening of cardiovascular disorders by two-dimensional echocardiography].

We used two-dimensional echocardiography (2-D echo) for the mass screening of 2,673 subjects for cardiovascular disorders (1,032 men, 1,641 women, aged 23-95 years with a mean age of 59), who lived in 12 rural areas in Japan. In 1,665 of the 2,673 subjects (62.3%), cardiac abnormalities were recognized. Three major abnormalities included sclerotic aortic (33.0%) and mitral valves (21.8%), and left ventricular (LV) hypertrophy (15.9%). Apparent pericardial effusion (54 cases), mitral valve prolapse (44 cases), and dilated cardiomyopathy (4 cases) were incidentally found in this study. Prevalence of the abnormalities insidiously increased with age (below 49 years: 39%, and above 80 years: 97%), and this was apparently higher in men than in women. The abnormal findings which were significantly higher in men were the sclerotic aortic valves, LV hypertrophy and dysfunction, the prevalence of which was particularly high in ages 40-79, but it became nearly equal beyond 80 years of age. These results may indicate a sexual difference in the influence of age on the cardiovascular system. It was concluded that 2-D echo is helpful for primary screening and prevention of cardiovascular disorders.

Adult↗
PubMed1988

Trehalase from the bean-shaped accessory glands and the spermatophore of the male mealworm beetle, Tenebrio molitor.

In Tenebrio molitor, male adults transfer sperm to the female via a spermatophore or sperm sac. The spermatophore is formed from secretions of the bean-shaped accessory glands (BAGs) and the tubular accessory glands (TAGs) of the male beetle. Trehalase is found in the adult BAGs. During the pupal stage, the activity in the BAGs was very low. After adult ecdysis, the total activity increased 100-fold from 0 days to 6 days and reached maximum levels at 9 days. The specific activity increased 20-fold from the time of ecdysis to 6 days thereafter. In the 10 day adult, trehalase levels in testes, seminal vesicles, vas deferens, TAGs, or ejaculatory ducts, were lower by two orders of magnitude than in the BAGs. However, the specific activity in the spermatophore was similar to that in the BAGs. Trehalases in the BAGs and the spermatophores showed very similar properties (soluble, optimum pH of 5.75 and Km value of 5.4 mM for trehalose). Thus trehalase appears to be secreted from the BAGs and becomes incorporated into the spermatophores.

Animals↗
PubMed1988

20-Hydroxyecdysone accelerates the flow of cells into the G1 phase and the S phase in a male accessory gland of the mealworm pupa (Tenebrio molitor).

The cells of the bean-shaped accessory glands of mealworms proliferate through the first 7 days of the 9-day pupal stage. Immediately after larval-pupal ecdysis, 25-27% of the cells were in the G1 phase, 60-65% were in the G2 phase, and the balance were in S phase. Over the first 4 days of normal development, the S fraction gradually increased, to reach its highest level in the mid-pupa at the time of the major ecdysteroid peak (Delbecque et al., 1978). Thereafter, the S fraction declined until over 95% of the cells had accumulated in G2 on Day 8. When 0-day pupal glands were explanted into Landureau's S-20 medium for 6 days, the G1 fraction remained fairly constant (25-30%) while S and the G2 fractions fluctuated. On the first day in vitro, the G2 fraction declined and the S fraction rose. On the second day in basal media, the S fraction fell and G2 rose correspondingly until 70% of the cells reached G2 when cycling stopped on the third day. With addition of 20-hydroxyecdysone to 0-day cultures, the S fraction increased quite sharply. It remained large for all 6 days of the experiment in the continuing presence of hormone. A 1-day pulse of hormone produced a transient increase in S. We blocked cell cycling with hydroxyurea in a stathmokinetic experiment and showed that 20-hydroxyecdysone accelerated the flow of cells from the G2 phase to the G1 phase by 2.5-fold. An increase in the G1 fraction was detected within 10 hr of hormone administration and the effect was dose-dependent with an ED50 of 5 X 10(-7) M for 20-hydroxyecdysone. We conclude that 20-hydroxyecdysone acts at a control point in the G2 phase. Incubation of the glands with 20-hydroxyecdysone for only 30-60 min followed by washout stimulated the flow from G2 to G1 and the effect persisted after transfer of the tissues to hormone-free media. Dose-dependent stimulation also occurred with ponasterone A (ED50 3 X 10(-9] but not with cholesterol.

Animals↗
PubMed1988

Primary pulmonary hypertension in pregnancy.

Primary pulmonary hypertension (PPH) is an uncommon but serious disease. Most patients with PPH are young women and the disease is more serious and eventful in pregnant women. We have experienced a patient with PPH in pregnancy, who was delivered successfully but died suddenly on the 7th day after the delivery. We report the obstetric course and the clinical management for the delivery of the patient with PPH.

Adult↗
PubMed1988

Effect of diapause hormone on cyclic nucleotide metabolism in developing ovaries of the silkworm, Bombyx mori.

1. The content of cyclic AMP and cyclic GMP in ovaries of the silkworm, Bombyx mori, changed differently depending on development. 2. The extirpation of suboesophageal ganglion caused cyclic AMP to decrease and cyclic GMP to increase at different developmental stages. 3. The reversed changes in the cyclic nucleotides were brought about by implantation of the ganglion or by injection of the diapause hormone preparation. 4. No change in both cyclic nucleotides was induced in ovaries during the first 24 hr after an injection of the hormone, but the clear effects appeared after a lag phase of a few days.

Animals↗
PubMed1988

Combination therapy with diltiazem and nifedipine in patients with effort angina pectoris.

The antianginal effects of diltiazem and nifedipine alone and in combination were evaluated in a double-blind, randomized, placebo-controlled trial in 11 patients (nine men and two women, 57 +/- 8 years old) with stable effort angina. Each patient received placebo, 30 mg of diltiazem, 10 mg of nifedipine, and 30 mg of diltiazem plus 10 mg of nifedipine four times daily for 1 week each. Antianginal efficacy was assessed by means of a treadmill exercise test. The exercise tolerance time was significantly prolonged from 235.1 +/- 52 (placebo period) to 342.2 +/- 101 sec by diltiazem (p less than .01) and to 325.6 +/- 73 sec by nifedipine (p less than .01). The drug combination further prolonged exercise time to 451.1 +/- 103 sec, which was significantly longer than the interval attained with either diltiazem (p less than .01) or nifedipine (p less than .01) alone. The plasma concentration of diltiazem was unaffected by the addition of nifedipine, whereas the plasma nifedipine concentration was significantly increased from 34.8 +/- 11 to 106.4 +/- 37 ng/ml (p less than .001) by the concomitant administration of diltiazem. These data suggest that exercise tolerance in patients with effort angina is increased by the concomitant administration of diltiazem and nifedipine associated with an increase in the nifedipine plasma concentration.

Adult↗
PubMed1988

Long-term survival of a patient with Lutembacher's syndrome.

An elderly woman with Lutembacher's syndrome remained asymptomatic until the age of 55, when she was treated for exertional dyspnea with digitalis and diuretics. She died of gastrointestinal hemorrhage and hepatic failure at the age of 69. The autopsy revealed a large atrial septal defect and mitral stenosis without rheumatic changes. This patient is the oldest reported survivor of Lutembacher's syndrome with nonrheumatic mitral stenosis.

Aged↗