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T Yasui

Publications and source records attributed to T Yasui.

At least 37 records · Page 2Linked to original sources
PubMed2001

Effects of citrate on renal stone formation and osteopontin expression in a rat urolithiasis model.

Previous studies have described the inhibitory effects of citrate on calcium oxalate crystallization in place of crystal growth, but the effects of citrate on matrix proteins of stones has not been studied in vivo. To examine the effect of citrate on the matrix, we investigated the effect of citrate on osteopontin (OPN) expression, which we had previously identified as an important stone matrix protein. Control rats were treated with saline while rats of the stone group were treated with ethylene glycol (EG) and vitamin D3, and the citrate groups (low-dose and high-dose groups) were treated with a citrate reagent compound of sodium citrate and potassium citrate, in addition to EG and vitamin D3. The rate of renal stone formation was lower in the citrate groups than in the stone group. This was associated with a low expression of OPN mRNA in citrate-treated rats relative to that in the stone group. Citrate was effective in preventing calcium oxalate stone formation and reduced OPN expression in rats. Our results suggest that citrate prevents renal stone formation by acting against not only the crystal aggregation and growth of calcium oxalate but also OPN expression.

Animals↗
PubMed2001

Distal stump of an occluded intracranial vertebral artery at the vertebrobasilar junction mimicking a basilar artery aneurysm.

The distal stump of an occluded intracranial vertebral artery (VA) can mimic a basilar artery aneurysm of the vertebrobasilar junction. Their differentiation is crucial to establishing the appropriate treatment. We report two cases with occlusion of the distal stump of the VA due to atherosclerosis and arterial dissection. Magnetic resonance images with three-dimensional constructive interference in steady state sequences are useful in revealing the occluded segment as a continuous anatomical structure from the proximal VA to the basilar artery. This information may prevent unnecessary exploratory surgery for a suspected basilar artery aneurysm.

Adult↗
PubMed2001

The therapeutic effect of lipo PGE1 on diabetic neuropathy-changes in endothelin and various angiopathic factors.

A high blood concentration of endothelin (ET)-1 may participate in the onset and progress of diabetic microangiopathy, resulting in neuropathy. We examined the therapeutic effects of prostaglandin E1 (PGE1), which possesses both a peripheral vasodilating action and inhibition of platelet aggregation, on diabetic microangiopathy. Increases in both skin temperature and peripheral never conduction velocity in diabetic patients were recorded four weeks after Lipo PGE1 administration. A quantitative decrease in urinary albumin concentration was also observed, suggesting its efficacy of action was on diabetic nephropathy. Lipo PGE1 administration reduced the elevated circulating plasma ET-1 levels in the diabetic patients. As an increase in ET-1 concentrations is thought to correlate with the onset and progress of diabetic microangiopathy, the reduction of plasma ET-1 concentration by Lipo PGE1 administration may be one reason for the improvement in diabetic neuropathy and nephropathy.

Adult↗
PubMed2001

Postmenopausal changes in serum cytokine levels and hormone replacement therapy.

OBJECTIVE: Our purpose was to investigate the effect of hormone replacement therapy on the postmenopausal changes in serum cytokine levels. STUDY DESIGN: Fifteen cytokines were measured by an enzyme-linked immunosorbent assay in 97 untreated and hormone replacement-treated women. Thirteen women were examined before and during hormone replacement therapy. RESULTS: Serum concentrations of macrophage colony-stimulating factor were significantly (P < .05) lower during the early postmenopausal period (< or = 10 years) than the values in premenopause and the elevated levels in the late postmenopausal period (< or = 30 years). A significant increase in tumor necrosis factor alpha and a decline in transforming growth factor beta1 were found in late postmenopausal women. Serum levels of macrophage colony-stimulating factor in women receiving hormone replacement therapy were significantly higher than those in untreated postmenopausal women. Furthermore, hormone replacement therapy induced a significant (P < .01) increase in serum levels of macrophage colony-stimulating factor, whereas serum levels of other cytokines were not affected. CONCLUSION: It is well documented that macrophage colony-stimulating factor lowers serum cholesterol concentrations and prevents atherosclerosis. Inducing the production of macrophage colony-stimulating factor is a possible additional mechanism of hormone replacement therapy in mediating the antiatherogenic effect.

Adult↗
PubMed2001

Effects of allopurinol on renal stone formation and osteopontin expression in a rat urolithiasis model.

BACKGROUND: The inhibitory effect of allopurinol on calcium oxalate urolithiasis has been reported, but its effect on stone matrix proteins has not been studied in vivo. To clarify the effect of allopurinol on the matrix, we investigated its effect on the expression of osteopontin (OPN), which we previously identified as an important stone matrix protein. METHODS: Control rats were not treated. Rats of the stone group were given ethylene glycol (EG) and vitamin D(3), while the allopurinol groups (low-dose group and high-dose group) were treated with allopurinol in addition to receiving EG and vitamin D(3). RESULTS: The rate of renal stone formation was lower in the allopurinol groups than in the stone group. This was associated with a low expression of OPN mRNA in allopurinol-treated rats relative to that in the stone group. CONCLUSION: Allopurinol was effective in preventing calcium oxalate stone formation and reduced OPN expression in rats. Our results suggest that allopurinol prevents renal stone formation by acting against not only the control of oxalate but also OPN expression.

Allopurinol↗
PubMed2001

Biological effects of hormone replacement therapy in relation to serum estradiol levels.

OBJECTIVE: Tissues in various parts of the body have different sensitivities to estradiol. However, it is very difficult to measure the serum estradiol levels precisely in women receiving oral conjugated equine estrogen, which is a mixture of estrogens. In the present study, we precisely measured the serum levels of estradiol in postmenopausal women undergoing hormone replacement therapy (HRT), and we clarified the relationships between serum estradiol levels and the effects of HRT on the Kupperman index, bone mineral density (BMD), serum gonadotropin, lipid metabolism and unscheduled bleeding as the clinical endpoints. METHODS: Sixty-eight postmenopausal or bilaterally ovariectomized women, aged 30-64 years, who had been suffering from vasomotor symptoms such as hot flush or atrophy of the vagina were randomly assigned to two groups: one group of 34 patients who received oral administration of 0.625 mg conjugated equine estrogen (CEE, Premarin, Wyeth) and 2.5 mg medroxyprogesterone acetate (MPA, Provera, Upjohn) every other day, and another group of 34 patients who received oral administration of 0.625 mg CEE and 2.5 mg MPA every day. All subjects were re-classified into three groups according to the serum estradiol level after 12 months of treatment: (1) low estradiol group (<15 pg/ml, n = 25); (2) middle estradiol group (> or =15 and <25 pg/ml, n = 27), and (3) high estradiol group (> or =25 pg/ml, n = 16). We examined the relationships between serum estradiol level and the effects of estradiol on the Kupperman index, BMD, serum gonadotropin levels, lipid profile and unscheduled bleeding in these three groups. RESULTS: RESULTS obtained by using our newly developed high-performance liquid chromatography (HPLC)-radioimmunoassay (RIA) system clearly showed that the effects on each tissue in postmenopausal women receiving oral CEE and MPA is closely related to estradiol level. The effects of HRT on BMD, serum gonadotropin levels and lipid profile were shown to be clearly dependent on the serum estradiol levels, while the effect of HRT on the Kupperman index was independent of the serum estradiol level. Furthermore, it was also found that a very low concentration of estradiol (<15 pg/ml) was sufficient to suppress the serum LH and FSH levels and to relieve vasomotor symptoms, and that the minimum concentration of estradiol required to increase BMD was 15 pg/ml. On the other hand, the level of estradiol required to reduce total cholesterol, low density lipoprotein-cholesterol (LDL-C) and apolipoprotein B (Apo B) was found to be more than 25 pg/ml, while the level required to increase high density lipoprotein-cholesterol (HDL-C) and apolipoprotein A1 (Apo A1) was at least 15 pg/ml. The incidence of unscheduled bleeding was also lower in the low estradiol group than in the other estradiol level groups. CONCLUSION: These results suggest that the different clinical endpoints have different response thresholds and thus reflect tissue sensitivity to estradiol levels achieved by HRT.

Adult↗
PubMed2001

Calcium oxalate crystal attachment to cultured rat kidney epithelial cell, NRK-52E.

Madin-Darby canine kidney (MDCK) cells have been used in research on crystal adhesion to epithelial cells. Recently, matrix proteins were identified, and studies of the genes and proteins expressed in renal epithelial cells have become active. The present study confirms the usefulness of the NRK-52E cell line, derived from the rat, in the study of attachment with calcium oxalate crystals. The calcium oxalate crystal suspension was distributed on top of the cells. After incubation, the monolayers were rinsed to remove non-associated crystals. After fixation, the association of crystals and NRK-52E cells was visualized using scanning electron microscopy. Calcium oxalate crystals were attached to the surface of NRK-52E cells. Under high magnification, many of the microvilli of the cells had elongated towards the crystals, and microvilli projections appeared to catch the crystals. The NRK-52E cell line is useful in the study of attachment between crystals and urinary epithelial cells in the kidney, especially for the regulation and analysis of genes and proteins.

Animals↗
PubMed2001

Effects of eicosapentaenoic acid on urinary calcium excretion in calcium stone formers.

OBJECTIVES: The low incidence of atherosclerosis and other degenerative disease, including urolithiasis, in the Greenland Eskimo has been attributed to their high consumption of oily fish with its high concentration of eicosapentaenoic acid (EPA). With a westernized diet, the oxygenated products of renal prostaglandin synthesis are metabolites of the n-6 series and these are known to play important roles in several pathophysiological processes involved in calcium stone formation. Buck's group presented a hypothesis that the initiating factor for lithiasis triggers prostaglandin synthesis, and showed that this influenced by EPA treatment. METHOD: In order to ascertain the effects of EPA on plasma lipids and urinary parameters, we undertook a clinical study whereby a highly purified preparation was administrated (1,800 mg/day) to 88 patients with urinary stones for 3 months (short term) and 18 months (long term). RESULTS: Hyperlipemia improved the affected individuals and urinary calcium was significantly reduced in the hypercalciuric but not in the normocalciuric group. CONCLUSION: The results suggest that EPA by reducing urinary calcium might favorably affect urine composition in a way that possibly reduces the risk of calcium stone formation.

Adult↗
PubMed2001

Transient increase in the levels of T-helper 1 cytokines in postmenopausal women and the effects of hormone replacement therapy.

The aim of this study was to determine, at least in part, T-cell function in postmenopausal women and the effects of hormone replacement therapy (HRT). Levels of T-helper 1 (Th1) cytokines (IL-2 and IFN-gamma) and T-helper 2 (Th2) cytokines (IL-4 and IL-10) produced by phytohemagglutinin-stimulated whole blood cells from 72 untreated and 44 HRT-treated women were measured by ELISA. Thirteen of the 44 HRT-treated women were examined before and during HRT. The production of IL-2 increased gradually with advance of the postmenopausal period. The levels of IL-2 in women in the early (< or =10 years) and mid (>10 and <30 years) postmenopausal stages were significantly higher than those in women in their second, third and fourth decades. The level in women in the late (> or =30 years) postmenopausal stage, however, was significantly lower than those in women in the early and mid postmenopausal stages. The level of IFN-gamma was highest in women in the mid postmenopausal stage. On the other hand, the levels of Th2 cytokines did not change with age or after menopause until the mid postmenopausal period but were significantly lower in women in the late postmenopausal stage. IFN-gamma levels in women on HRT were significantly lower than those in untreated postmenopausal women at all postmenopausal stages. HRT induced a significant decrease in the production of IL-2 and IL-4. In conclusion, production of Th1 cytokines is augmented in women after menopause. HRT prevents this increase, thereby improving the aberration of Th1/Th2 balance that is implicated in an inadequate immune response and pathological conditions.

Adolescent↗
PubMed2001

Expression of ovarian prolactin receptor in relation to hormonal changes during induction of ovulation in the rat.

We examined the relationships between the expression of the short and long forms of the prolactin (PRL) receptor (PRLR) mRNA in the ovary and changes in the levels of serum hormones such as sex steroid hormones and PRL during induction of ovulation in the rat. The expression of both forms of PRLR mRNA in the ovary was examined by Northern blot analysis in immature female rats treated with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG). Ovarian tissues and blood samples were obtained before treatment, 24 and 48 h after PMSG injection and 4, 6, 8, 12, 24 and 48 h after hCG treatment. Serum levels of 17beta-estradiol, progesterone and PRL were determined by radioimmunoassay. Serum levels of 17beta-estradiol rapidly increased to a maximal level 48 h after PMSG injection and then rapidly declined until 4 h after hCG injection. Serum levels of progesterone gradually increased after PMSG treatment, markedly increased to 114.2 nmol/l 8 h after hCG treatment and remained high until 48 h after hCG treatment. The serum level of PRL peaked at 66.2 microg/l (p < 0.01) 48 h after PMSG injection, and a temporary decrease after hCG treatment was followed by a continuously high level from 8 to 48 h. The expression of the long form of PRLR mRNA increased significantly (p < 0.01) to 688% of the control level after PMSG treatment, while that of the short form increased to only 184% of the control level. The expression of the long form of PRLR-mRNA rapidly declined until 6 h and then gradually increased until 48 h after hCG treatment. On the other hand, the expression of the short form of PRLR mRNA decreased to a nadir 12 h after hCG injection and then increased significantly (p < 0.01) to 142% of the control level. Our results showed that the changes in the short and long forms of PRLR mRNA differed in a time-specific manner and that these two forms are involved in different functions in the rat ovary during induction of ovulation. It is thought that the long form of PRLR mRNA is involved in folliculogenesis, while the short form of PRLR mRNA may play an important role in the formation and maintenance of the corpus luteum in the rat ovulatory cycle.

Animals↗
PubMed2001

Efficacy of every-other-day administration of conjugated equine estrogen and medroxyprogesterone acetate on gonadotropin-releasing hormone agonists treatment in women with endometriosis.

We performed a randomized controlled study to determine the efficacy of add-backed therapy by every-other-day administration of 0.625 mg conjugated equine estrogen (CEE) and 2.5 mg medroxyprogesterone acetate (MPA) on GnRH agonists (GnRH-a) treatment in Japanese women with symptomatic endometriosis. At the end of treatment, serum estrone and estradiol levels in the add-back group (n = 11) were significantly higher than those in the control group (n = 10). The assessment of Beecham classification by bimanual examination, serum CA-125 levels, and the frequency of genital bleeding revealed no significant differences between the two groups. The add-back group showed reduced Kupperman indices relative to those of the control group, and could prevent the loss of bone density. These findings led to a conclusion that GnRH-a therapy added back by every-other-day administration of 0.625 mg CEE and 2.5 mg MPA was a safe and effective treatment for Japanese women with endometriosis.

Adult↗
PubMed2001

Visual demonstration of calcium accumulation in human arteries of upper and lower limbs.

To elucidate the calcium content of the arteries in the upper and lower limbs, the authors determined the calcium content of all the arteries in the upper and lower limbs continuously by microwave-induced plasma-atomic emission spectrometry. The subjects were an 87-yr-old man and a 72-yr-old woman. The calcium content was determined both in the arteries of the upper limbs continuously, such as the subclavian arteries and its distal arteries, and in the arteries of the lower limbs, such as the common iliac arteries and its distal arteries. The common finding that the higher accumulation of calcium occurred in the arteries of the lower limbs in comparison to the arteries of the upper limbs and extremely high accumulation of calcium occurred in the common, external, and internal iliac arteries was obtained in the two subjects. The calcium content of the arteries in the upper and lower limbs was visually demonstrated.

Aged↗
PubMed2001

Effects of leptin on secretion of LH and FSH from primary cultured female rat pituitary cells.

BACKGROUND: Leptin, which is the product of the obese gene, is believed to play important roles in pubertal development and reproductive function in females. In a study using adult male rats, it was found that leptin stimulated secretion of gonadotropin from the pituitary in a dose-related manner. However, there has been no such study in female rats. OBJECTIVE: To investigate the effects of leptin on the production of LH and FSH from the pituitary in female rats, using primary cultured pituitary cells. METHODS: In this study, we determined body weight, serum leptin concentration and serum estradiol (E(2)) concentration in female Wistar rats at 3, 5, 6, 7, 9 and 11 weeks of age, and cultured pituitary cells from 6-week-old female Wistar rats with leptin (0--10(-7) mol/l) and GnRH (0 or 10(-8) mol/l). Then basal and GnRH-stimulated extra- and intracellular LH and FSH were assayed by RIA. RESULTS: Serum leptin concentration increased with increases in body weight and E(2) concentration. The pubertal serum leptin concentration was about 10(-10) mol/l. At a lower or moderate concentration, leptin produced dose-related increases in both basal and GnRH-stimulated extra- and intracellular LH and FSH in pituitary cells. At a concentration of 10 mol/l, leptin significantly (P<0.05) stimulated both basal and GnRH-stimulated extra- and intracellular LH and FSH. However, at greater concentrations, these effects diminished. CONCLUSIONS: These results indicated that leptin induced pituitary cells to produce and secrete both LH and FSH, with or without GnRH. The concentration of leptin that induced the greatest production of gonadotropins by pituitary cells was 10(-10) mol/l, which was the same as the physiological pubertal concentration. Leptin may be involved in the onset of puberty. It is also conceivable that leptin may be a cause of ovulatory failure, not only in weight loss but also in weight gain.

Animals↗
PubMed2001

"Early" apoplexy due to traumatic intracranial aneurysm--case report.

A 76-year-old man presented with a traumatic aneurysm of the left internal carotid artery which caused repeated subarachnoid hemorrhages within 20 hours of a fall from a height. Early computed tomography (CT) detected no brain abnormalities, but repeat CT found subarachnoid hemorrhage. Internal carotid angiography detected a pseudoaneurysm, which was not treated because of his poor clinical condition. He died of multiple organ failure. Early detection of a traumatic intracranial aneurysm is important for the prevention of aneurysmal rupture, or "delayed" apoplexy. Review of 171 cases with traumatic aneurysms from the literature found that false negative angiography occurred only in three cases on post-trauma day 7 and thereafter. Early diagnostic angiography within a week of the initial trauma is indicated if traumatic aneurysm is suspected to detect early signs of irregularity, spasm, and narrowing of the arterial wall. Repeat angiography is indicated if aneurysmal formation is still highly suspected in spite of negative initial angiography.

Acute Disease↗
PubMed2001

Moyamoya disease and coronary artery disease--case report.

A 26-year-old female with idiopathic moyamoya disease developed chest pain with concomitant ST depression on electrocardiography. Coronary angiography detected no stenotic lesions in the epicardial coronary arteries. The clinical diagnosis was vasospastic angina pectoris. She was medicated with calcium antagonists, which reduced the frequency of chest pain episodes. Angina pectoris is a rare occurrence in young patients with moyamoya disease. Coronary artery disease and moyamoya disease may have common etiological factors.

Adult↗
PubMed2001

Evolution of incidentally-discovered fusiform aneurysms of the vertebrobasilar arterial system: neuroimaging features suggesting progressive aneurysm growth.

This study investigated the natural history and biological behavior of incidental fusiform aneurysms in four patients with incidental fusiform aneurysms of the vertebrobasilar arterial system who had been followed up for more than 3 years (mean 3.5 years). Two lesions remained the same size, and two lesions gradually grew. Angiography showed the non-growing fusiform aneurysms as a circumferentially or unilaterally fusiform dilatation of a short segment of the vertebral artery with smooth walls and a steep slope of the dilatation, and the growing fusiform aneurysms as unilaterally fusiform involving a long segment of the vertebral artery or basilar artery with irregular walls and a gentle slope of dilatation. Magnetic resonance (MR) imaging demonstrated the non-growing fusiform aneurysms as a signal-void area, and the growing fusiform aneurysms as high and intermediate signals in addition to the normal flow void. The heterogeneous MR intensities probably correspond to turbulent flow, laminar flow, thrombosis, or intramural hematoma. Differentiation of growing and non-growing fusiform aneurysms is very difficult at the initial diagnosis. However, enlargement of the fusiform aneurysms is consistent with hemorrhage into the aneurysmal wall, which is confirmed by MR imaging. Fusiform aneurysms with the characteristics of the growing aneurysms cannot be overlooked because of the potential to develop into giant fusiform aneurysms which are very difficult to manage therapeutically.

Cerebral Angiography↗
PubMed2001

High incidence of arterial dissection associated with left vertebral artery of aortic origin.

The incidences of arterial dissection of the vertebral artery (VA) of aortic origin and VA of subclavian artery origin were determined. The origins of the left and right VAs were confirmed by angiography in 860 and 717 patients, respectively. Left VA of aortic origin was found in 21 patients (6 females and 15 males) but no right VA of aortic origin was found. Left VA of left subclavian artery origin was found in 837 patients and right VA of right subclavian artery origin in 717 patients. Arterial dissection of the VA occurred in 17 patients (6 females and 11 males), four patients with left VA of aortic origin, seven with left VA of left subclavian artery origin, four with right VA of right subclavian artery origin, and two with bilateral VAs of subclavian artery origin. Left VA of aortic origin (4 of 21 patients) was associated with a significantly higher incidence of VA dissection than left VA of left subclavian artery origin and right VA of right subclavian artery origin (p < 0.001). Left VA of aortic origin is associated with a predilection for VA dissection in comparison to VA of subclavian artery origin.

Aortic Dissection↗