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Biomedical subjects

N Terada

Publications and source records attributed to N Terada.

At least 361 records · Page 20Linked to original sources
PubMed1986

Vasomotor center controls of the hepatic circulation during blood pressure oscillation in rabbits.

Changes in hepatic hemodynamics during blood pressure oscillations caused by the side pressure exertion procedure (SPEP) were studied in anesthetized rabbits. The brain was excluded from systemic circulation except for one of the common carotids, which was compressed with stepwise elevated pressure. In normovolemia, the hepatic arterial flow (HAF) increased as the systemic arterial pressure (SAP) rose up to 140 mmHg, and then decreased as SAP rose further. With the rise of SAP, the portal venous flow (PVF) initially rose slightly, followed by a nearly constant decrease. Hemorrhaging influenced slightly the changes of HAF and PVF with the SAP rise. After volume loading, SAP and PVF markedly increased but HAF changed little. However, the initial increase in HAF with the SAP rise was markedly depressed by volume loading. PVF conspicuously decreased without initial increase with the rise in SAP. The hepatic vascular bed has a mechanism that prevents expected decrease of blood flow after hemorrhaging and during neurogenic hypertension. The interaction among HAF, PVF, and PVP may be involved in this mechanism.

Animals↗
PubMed1985

Some species differences in cardiovascular responses to intravenously injected leucine-enkephalin.

Studies were conducted to determine the cardiovascular responses to leucine-enkephalin (L-enk) in three different species of animals; rabbit, dog and monkey. All animals were anesthetized with pentobarbital sodium after sedation with ketamine. Mean blood pressure (MBP) and heart rate (HR) were simultaneously monitored. The pressor and HR responses to bilateral carotid occlusion (BCO) were determined before injection of L-enk. Increased MBP and HR due to BCO in monkey were significantly greater than in the other two animal groups. Following i.v. injection of L-enk (5-30 micrograms/kg), a significant fall in MBP occurred in all groups in a dose-dependent manner; however, the time course of changes in MBP in rabbits was significantly shorter than that in the other animal groups. Significant decreases in HR after the injection of L-enk occurred in rabbits and dogs, whereas increases in HR occurred in monkeys. These results show that some cardiovascular responses to L-enk may be species dependent. These different cardiovascular responses to L-enk may be at least partly related to species differences in baroreceptor reflex sensitivity.

Animals↗
PubMed1985

Age-dependent change in sensitivity of oestrogen-induced uterine cell proliferation of mice, estimated by incorporation of [125I]iododeoxyuridine.

The stimulative effects of both oestradiol-17 beta (E2) and diethylstilbestrol (DES) injections on the proliferation of uterine cells of mice were investigated by using 5-[125I]iodo-2'-deoxyuridine [( 125I]IdUrd) incorporation as an index. Female mice of (WB X C57BL/6)F1 were neonatally castrated, and the [125I]IdUrd uptake by the whole uterus was determined on days 1, 5, 10, 20, 30 and 40 after birth. The relative minimal dose (a minimal dose expressed per body weight, microgram/g b.wt) of E2 necessary for the maximal [125I]IdUrd uptake was much higher than the relative minimal dose of DES on days 1, 5, and 10, when the serum concentration of alpha-fetoprotein was relatively high. However, the relative minimal dose of E2 was comparable to that of DES on days 30 and 40, when the concentration of alpha-fetoprotein was negligible. The difference between the effect of injected E2 and DES during neonatal and suckling periods seems to be attributable to the presence of alpha-fetoprotein in serum, which binds to E2 but not to DES with high affinity. When the relative minimal dose of DES necessary for the maximal [125I]IdUrd uptake was examined in detail, the value was lower on days 10 and 20 of age than on days 30 and 40 of age. This might represent the increased sensitivity of uterine cells to oestrogen on days 10 and 20.

Aging↗
PubMed1985

Effect of serum and 12-O-tetradecanoyl-phorbol-13-acetate on FSH-stimulated conversion of 4-androstene-3,17-dione to oestrogens in cell and organ cultures of suckling mouse ovaries.

The effect of serum and 12-O-tetradecanoylphorbol-13-acetate (TPA) on the FSH-stimulated oestrogen production was studied in both cell and organ cultures. Ovaries were removed from (WB X C57BL/6)F1 mice at 9-days of age, and the conversion of 4-androstene-3,17 -dione to oestrogens was stimulated by the addition of FSH in vitro. Either 10% serum (fetal calf, mouse, rat and horse) or 0.1 microM TPA markedly inhibited the FSH-stimulated oestrogen production by dispersed and cultured ovarian cells. In contrast, neither serum nor TPA influenced the oestrogen production in the organ culture. This suggests that the presence of tissue architecture may prevent the inhibitory effect of serum and TPA on the FSH-stimulated oestrogen production.

Androstenedione↗
PubMed1985

Urinary retention induced by estrogen injections in mice: an analytical model.

Daily subcutaneous injections of pharmacological doses of 17 beta-estradiol (E2, 0.4 micrograms./gm. body weight) resulted in significant urinary retention in the bladder of castrated mice. Although the urinary retention developed in both male and female mice, the increase in urethral resistance to urinary flow and the dilatation of posterior urethra were observed only in castrated male mice receiving E2. Histological changes common to male and female mice were cornification and stratification of urethral epithelium and fibrosis of connective tissues surrounding the urethra, suggesting that these changes may cause the urinary retention. Although the exact mechanism has not been defined, the urinary retention produced by the present method may be useful as a model of human disease.

Animals↗
PubMed1985

Estrogen-induced increase in eosinophil number and peroxidase activity in uterus of genetically mast cell-deficient W/Wv mice.

The role of mast cells in induction of uterine eosinophilia was investigated by using genetically mast cell-deficient (WB X C57BL/6)F1-W/Wv (hereafter called WBB6F1-W/Wv) mice. The injection of estradiol-17 beta (0.16 micrograms/g body weight) increased the peroxidase activity and eosinophil number in the uteri of castrated WBB6F1-W/Wv and WBB6F1-+/+ mice. Since no significant differences were detectable between these two type of mice, mast cells did not seem to be essential for the estrogen-induced uterine eosinophilia, at least in mice.

Animals↗
PubMed1985

Efficiency and limitations of the upper airway mucosa as an air conditioner evaluated from the mechanisms of bronchoconstriction in asthmatic subjects.

To elucidate a limit to the efficiency of the upper airway mucosa as an air conditioner, the temperatures of the inspiratory air and mucosa were measured in the cervical trachea. Both of them were affected only minimally by change of atmospheric air temperature during resting nose breathing, but were affected greatly by change of mode of breathing. During hyperventilation through the mouth, when the atmospheric air temperature was 1 degree C, a temperature difference of 9 degrees C was noted between inspiratory air in the cervical trachea and body temperature, together with a mucosal temperature fall by 1.86 +/- 0.61 degree C. Wearing of a mask caused a rise of 3 degrees C in the inspiratory air temperature in the cervical trachea.

Adult↗
PubMed1985

Cholinergic muscarinic receptor in the nasal mucosa of guinea pigs with bronchial asthma with and without hypersensitive nasal symptoms.

Using [3H]-quinuclidinyl benzilate (QNB) as a radioligand, receptor binding assay was performed to evaluate the changes of the muscarinic receptor in the nasal mucosa of guinea pigs sensitized with toluene diisocyanate (TDI), which showed hypersensitive airway symptoms both in the lower airway and in the nose. The same study was performed in guinea pigs sensitized with bacterial crystalline alpha-amylase (BCA) which showed typical symptoms of bronchial asthma but without hypersensitive nasal symptoms. In the nasal mucosa of guinea pigs sensitized with TDI, an increased density of the muscarinic receptor was confirmed with no change in affinity of the receptor. However, in the nasal mucosa of guinea pigs sensitized with BCA, no changes were observed either in the density of the muscarinic receptor of the nasal mucosa or in its affinity. The increased density of the muscarinic receptor observed in subjects with nasal allergy, which was reported earlier, is not specifically related to IgE-mediated nasal allergy and is not induced by systemic sensitization itself but is assumed to be induced by some pathophysiological changes in the nasal mucosa including antigen-antibody reaction with development of hypersensitive nasal symptoms.

Animals↗
PubMed1985

Heterogeneity in mouse seminal vesicle epithelial cells responding to androgen as evaluated by incorporation of [125I]iododeoxyuridine.

When the uptake of 5-[125I]iodo-2'-deoxyuridine ([125I]IdUrd) into the seminal vesicle of castrated mice was measured 3 days after starting injections of various doses of testosterone propionate (TP), logarithmic values of [125I]IdUrd uptake were proportional to the logarithmic doses of TP in the range of 0.04-2 micrograms/g BW. The [125I]IdUrd uptake values correlated well with the labeling and mitotic indices of epithelial cells. Since daily injections of 0.4 microgram TP/g BW did not increase significantly the weight or DNA content or protein content of the seminal vesicle, the [125I]IdUrd uptake is a sensitive index of androgen action. Moreover, this suggests that low doses of androgen induce division of epithelial cells without resulting in the increase in cell number. The [125I]IdUrd radioactivity in the seminal vesicle was measured 2-15 days after the injection of [125I]IdUrd, since the value represented the fraction of surviving cells synthesizing DNA at the time of [125I]IdUrd injection. When injections of 4 micrograms TP/g BW were continued, the incorporated radioactivity was retained. In contrast, continuous injections of 0.2 microgram TP/g BW did not maintain the radioactivity, of which incorporation was induced by the same dose of TP. Thus, the present result suggests the presence of heterogeneity in androgen-responsive epithelial cells of the seminal vesicle.

Animals↗
PubMed1985

[Regional cerebral blood flow in cerebrovascular disease studied using N-isopropyl-p-(123I) iodoamphetamine].

Twenty-one patients with cerebrovascular disease (5 with hemorrhage, 10 with infarction, 2 with TIA, 4 with motor disturbance of unknown cause) were studied using N-isopropyl-p-(123I)iodoamphetamine (123I-IMP) and single photon emission CT. In 3 of 5 cases with cerebral hemorrhage, perfusion defects were shown in and around the region of hematomas, furthermore, one of the cases with internal capsular hematoma, the perfusion defect extended to the cortical area corresponding to the neurological pathway. In one case with MCA infarction, the perfusion defect was greater and clearer than the low density area on X-ray computed tomography (CT). These results revealed the 123I-IMP study provides physiological information in contrast with X-ray CT which provides anatomical information. In 3 of 9 cases with multiple small deep hemispheric infarctions on X-ray CT, the perfusion to the basal ganglia was suspected to be decreased on 123I-IMP images. However, this visual findings was not definitive and, in fact, the diseased side was not always consistent with the clinical findings. For quantitative analysis, symmetrical regions of interest (ROIs) were constructed both basal ganglia and the ratio of average counts over the ROI to those over the whole slice was calculated. In the small infarction group, the mean +/- S.D. of the values was 0.89 +/- 0.09 in right and 0.89 +/- 0.08 in left. Although the values were not significantly different from those of normal subjects (0.99 +/- 0.02 in right, 0.97 +/- 0.03 in left), they distributed in the range less than normal in 5 of 9 cases. This method was thought to be useful and practical to evaluate the cerebral blood flow in basal ganglia of patients with deep hemispheric infarction.

Amphetamines↗
PubMed1985

Uterotropic hormones produced by ovaries of Sl/Slt mutant mice before spontaneous development of tubular adenomas.

Tubular adenomas developed spontaneously in ovaries of (WB X C57BL/6)F1-Sl/Slt and -W/Wv mice after 150 days of age. The uteri of the W/Wv mice were hypoplastic before development of tubular adenomas, but the uteri of the Sl/Slt mice were not. Since oophorectomy significantly reduced the uterus weight in the Sl/Slt mice, we investigated the androgen- and estrogen-producing activity of Sl/Slt and W/Wv mice before development of tubular adenomas. Fragments of ovaries were cultured for 48 hr in serum-free medium containing either progesterone or 4-androstene-3,17-dione (androstenedione). The amount of androgens produced from progesterone by ovaries of Sl/Slt mice in the presence of human chorionic gonadotropin was comparable to that of W/Wv mice. In contrast, the amount of estrogens produced from androstenedione by ovaries of Sl/Slt mice in the presence of follicle stimulating hormone was much greater than that of W/Wv mice. Moreover, the amount of estrogens produced was much greater than the amount of androgens in the ovaries of Sl/Slt mice. Therefore, before development of tubular adenomas, estrogens rather than androgens seem to be a major uterotropic hormone produced by ovaries of Sl/Slt mice.

Adenoma↗
PubMed1985

Mechanism of estrogen enhancement in the growth of androgen-dependent Shionogi carcinoma 115.

The mechanism of estrogen enhancement in the growth of androgen-dependent Shionogi carcinoma 115 (SC115) maintained in castrated DS mice by low doses of androgen (10 micrograms of testosterone propionate or 4 micrograms of 5 alpha-dihydrotestosterone/mouse/day) is reported. Although the low androgen treatment slightly but significantly (P less than 0.05) stimulated tumor growth, concomitant estrogen (4 micrograms of 17 beta-estradiol/mouse/day) significantly (P less than 0.01) enhanced the tumor growth. The high growth rate, histological type (medullary carcinoma), androgen dependency, and high androgen receptor content of the tumor grown during estrogen plus low androgen treatment did not differ significantly from those of the original SC115 tumor grown in normal males or in castrated mice treated with high doses of androgen. On the other hand, the treatment with low doses of androgen alone induced the development of slowly growing spindle-shaped cells from the medullary SC115 cells. The spindle-shaped cells containing low levels of androgen receptor were shown to be androgen independent and were also induced from the SC115 cells in nontreated castrated mice. These findings demonstrated that low doses of androgen and estrogen synergize to maintain and increase the growth of SC115 cells, whereas low doses of androgen alone fail to maintain the SC115 cells.

Androgens↗
PubMed1985

The mechanisms of systemic symptoms following nasal administration of allergens.

A nasal provocation test was performed by consecutively placing allergen discs on the nasal mucosa of patients with pollinosis. This brought easily the systemic symptoms such as cough, periorbital oedema, and urticaria. Similarly, the nasal administration of large doses of the allergen induced a change in the respiratory response in sensitized guinea pigs. These results indicate that nasal mucosa absorbs a high molecular substance such as allergens.

Administration, Intranasal↗
PubMed1984

Augmentation of aromatase activity by FSH in ovaries of fetal and neonatal mice in organ culture.

The stimulative effect of FSH on aromatase activity was investigated in ovaries of fetal (on days 17 and 18 of gestation) and neonatal mice (on days 0, 3, 6 and 9 after birth). Two to six ovaries, were cultured for 48 h in 2 ml of Medium 199 supplemented with insulin (5 micrograms/ml) and [1 alpha, 2 alpha, 6 alpha, 7 alpha, beta-3H]4-androstene-3,17-dione (0.35 microM) in the presence or absence of porcine FSH (0.5 units/ml) and the amount of [3H]oestradiol-17 beta and [3H]oestrone produced was estimated. In the presence of FSH, aromatase activity per ovary, which was found in all fetal and neonatal ovaries examined, increased with age. In the absence of FSH, however, the production of oestrogens could be demonstrated only in ovaries from 3- to 9-day old mice. FSH increased the aromatase activity by up to 10-fold. In spite of the stimulative effect of FSH on aromatase activity, FSH exerted no significant effect on DNA synthesis of the ovaries. The formation of primordial follicles could not be observed histologically in ovaries of fetal mice on day 17 of gestation, although the ovaries of 6- and 9-day old mice contained multilayered follicles. These results show that FSH stimulates the aromatase activity of the mouse ovary even before the formation of primordial follicles and that the stimulative effect of FSH on ovarian aromatase is not due to the proliferation of ovarian cells.

Androstenedione↗
PubMed1984

5 Alpha- and 5 beta-reductases for 4-ene-3-ketosteroids and 17 beta-ol-dehydrogenase in epididymis and testis of golden hamster during sexual development.

Homogenates of the epididymis, testis and seminal vesicle from 15, 25, 35 and 60-day old golden hamsters were incubated with [3H]4-androstene-3,17-dione and NADPH and enzyme activity was estimated. In the testis, activities of 5 alpha- and 5 beta-reductases were the highest (32 +/- 4 and 68 +/- 13 (SD) nmol/100 mg protein/h, respectively) at 25 days of age, moderately high at 35 days and very low (1-3 and 5-6, nmol/100 mg protein/h, respectively) at 15 and 60 days. In the epididymis, 5 alpha-reductase activities increased with age during sexual development by up to 50-fold and reached the maximum value (40 +/- 11 nmol/100 mg protein/h) at 60 days. The 5 alpha-reductase activities in the seminal vesicle were found to be relatively low (0.5-1 nmol/100 mg protein/h), compared with those in the epididymis and testis. Activities of 5 beta-reductase in the epididymis and seminal vesicle were very low (0.1-0.5 nmol/100 mg protein/h) at all ages. These results indicate the existence of a marked, but transient, increase in 5 alpha- and 5 beta-reductase activities during immature period in the testis of golden hamster. In the epididymis, however, 5 alpha-reductase activity increases with age during sexual maturation, while 5 beta-reductase activity is almost undetectable at all ages.

17-Hydroxysteroid Dehydrogenases↗