Biomedical subjects

T Yahata

Publications and source records attributed to T Yahata.

At least 73 records · Page 4Linked to original sources

PubMed1995

Effects of progesterone on the metabolism of cancellous bone in young oophorectomized rats.

The effects of progesterone on cancellous bone in young rats were evaluated. Fifty female rats aged 90 days were divided into 5 groups: (1) Sham-operated controls (SHAM); (2) oophorectomized (OVX) rats; (3) OVX rats treated with estrogen (OVX+E); 4) OVX rats treated with progesterone (OVX+P); and (5) OVX rats treated with estrogen and progesterone (OVX+EP). After surgery, some animals were treated subcutaneously (s.c.) with 0.5 mg of estradiol dipropionate depot, with 5 mg of hydroxyprogesterone capronate depot, or with both hormones, at intervals of 7 days. After 180 days, the bone mineral density (BMD) and bone histomorphometry of their lumbar vertebrae and serological parameters were measured. In the OVX+P group, the BMD and the bone volume as shown by bone histomorphometry were slightly higher than in the OVX group, but not significantly. These parameters in the OVX+E and OVX+EP groups were significantly higher than in the OVX group. The OVX+P group showed a significant increase in the labeled surface and a decrease of the osteoclast number, compared to the OVX group. The OVX+P group showed increases of serum alkarine phosphatase and osteocalcin. From these results, it can be concluded that progesterone treatment might intensify bone formation and suppress bone resorption on cancellous bone in oophorectomized rats, although progesterone alone does not have a positive effect on BMD and bone volume.

Animals↗

PubMed1995

[The significance of bone mineral density measurement of premenopausal women].

We examined the starting age for measuring bone mineral density (BMD) in premenopausal women to detect osteopenia as soon as possible. BMD of the second to fourth lumbar spine vertebrae was measured by dual-energy X-ray absorptiometry to determine normal values for 500 healthy premenopausal women (aged from 17 to 55). We found the rate for low BMD premenopausal women, whose BMD was under the peak bone mass-2SD. And we compared normal BMD women with low BMD women with reference to menstrual history, obstetrical history, and life style, by means of a questionnaire. The peak bone mass of premenopausal women was reached between 35 and 39 years of age (1.059 +/- 0.097g/cm2). The low BMD rate was 7% in all premenopausal women, and increased to 13.5% at from 45 to 49 years. On the other hand, it was only from 5.7 to 7.4% even at from 20 to 29 years. There was the positive correlation between BMD and the body mass index (BMI). There was no statistically significant difference between the low BMD women and the normal BMD women in menstrual history, obstetrical history or life style (parity was 1.7 +/- 1.6 and 1.1 +/- 1.2, respectively, p < 0.05). We concluded that premenopausal women should have their BMD measured after aged 45, and be measured once from 20 to 40 years of age if possible.

Absorptiometry, Photon↗

PubMed1995

[Inhibitory effect of low molecular weight heparin on the bronchoconstriction in ovalbumin-sensitized guinea pigs after antigen exposure].

To elucidate the effect of low molecular weight heparin (LMWH) on the bronchoconstriction, we examined the serial changes of the resistance of respiratory system (Rrs) in ovalbumin (OA)-sensitized guinea pigs after antigen exposure. After sensitization of guinea pigs with repeated OA inhalation, Rrs was measured at immediate asthmatic response (IAR) and late asthmatic response (LAR) with or without LMWH inhalation. Alteration in the number of inflammatory cells of the lung by LMWH inhalation was examined in the broncholaveolar lavage fluid (BALF) and in the histological sections of airway walls. Peak Rrs at 1 min up to 9 min, except 8 min, after antigen exposure significantly decreased by the pretreatment with LMWH inhalation as compared with saline inhalation. Peak Rrs at LAR (after 4 hours up to 24 hours, except 6 hours) also showed a significant decrease in the pretreatment with LMWH inhalation. Pretreatment of LMWH exhibited a decrease of eosinophil percentage in BALF (5.5 +/- 1.2% from 8.2 +/- 0.4% in saline inhalation) and a decrease of infiltrated eosinophil count in airway walls (71.0 +/- 7.3 from 155 +/- 15.8 in saline inhalation). These data show LMWH might play an important role as an inhibitory factor to bronchial asthma.

Administration, Inhalation↗

PubMed1994

[Bronchial hyperresponsiveness and relaxability in patients with mitral stenosis].

To study the differences in bronchial responsiveness to inhaled methacholine and salbutamol between patients with mitral valve disease those with bronchial asthma a bronchial provocation test (Astograph) and pulmonary function tests were done in 25 patients with mitral stenosis (MS) and 18 patients with bronchial asthma (BA). We derived an index of airway reloxability from the effect of salbutamol after precontraction with inhaled methacholine. This index was the change in respiratory conductance (Grs) over time during inhalation of salbutamol (SGrs-d). It was computed as SGrd = delta Grs/delta t. Eighteen patients with MS (72%) showed bronchial hyperresponsiveness (BHR) to methacholine. The MS patients with BHR (MS(+)) had lower values of the ratio of the forced expiratory volume in one second to the forced vital capacity (FEV/FVC) and maximal expiratory flow at 25% of vital capacity (V25) than MS patients without BHR (MS(-)). There was a significant correlation between V25 and the log cumulative dose producing a 35% decrease in respiratory conductance (PD35Grs) in MS(+). The mean log Dmin of MS(+) was significantly higher than that of the patients with BA (0.14 +/- 0.64 log units and -0.30 +/- 0.65 log units, p < 0.05, respectively). The mean log PD35Grs of MS(+) was also significantly higher than that of the patients with BA (1.09 +/- 0.53 log units and 0.45 +/- 0.66 log units, p < 0.01, respectively). Indices of relaxability (SGrs-d and SCrs-d/Grs-d) in MS(+) were significantly lower than in BA patients. Indices of hyperresponsiveness and relaxability were both significantly lower in patients with MS than in patients with BA.(ABSTRACT TRUNCATED AT 250 WORDS)

Albuterol↗

PubMed1994

[Effect of hormone replacement therapy on lipid metabolism in patients with premature ovarian failure and Turner's syndrome].

Premature ovarian failure (POF) and Turner's syndrome patients who are also hypoestrogenomic, like postmenopausal women, are considered to be a high risk group for hyperlipemia. Our long-term study was conducted to evaluate the effect of hormone replacement therapy (HRT) on lipid metabolism in 16 POF and 10 Turner's syndrome women. 1. The initial average total cholesterol (TC) of the untreated and treated POF patients (209, 196mg/dl) and that of untreated and treated Turner's syndrome patients (213, 240mg/dl) were significantly higher than those in the control group (175mg/dl) except treated POF patients. LDL cholesterol (LDL-C) of the untreated and treated POF patients (135, 113mg/dl) and that of untreated and treated Turner's syndrome patients (142, 144mg/dl) were significantly higher than those in the control group (108mg/dl) except treated POF patients. In comparison to healthy women of a similar age, POF and Turner's syndrome patients were at high risk of hyperlipemia because of higher serum TC and LDL-C levels. 2. After HRT for 2 years, LDL-C decreased by 18% and 13%, and HDL cholesterol increased by 38% and 41% in POF and Turner's syndrome patients, respectively. Hence AI decreased by 40% and 50% respectively. The younger the hyperlipemic patients are, the higher the relative risk for atherosclerosis is. The results of this study suggest that, because of the beneficial effects of HRT on serum lipid metabolism, it can help to prevent the development of coronary heart disease.

Adult↗

PubMed1994

[An efficient methods for the induction of human antitumor effector CD4+ and CD8+ T cells: their application to tumor immunotherapy].

It is an important issues to investigate an efficient methods to induce antitumor effector T cells from peripheral blood lymphocytes of tumor patients for the development of a novel tumor immunotherapy. We established a large scale culture system of human CD4+ helper/killer T cells which have both helper and killer functions. Targeting of CD4+ helper/killer T cells to tumor using anti-CD3 x anti-c-erbB-2 mAb caused the lysis of tumor and triggering of IL-2 production. It was also demonstrated that culture of human CD4+ T cells with staphylococcal enterotoxin A (SEA) or IL-12 caused a selective induction of Th1 type of CD4+ helper/killer T cells. IL-12 also revealed a novel effect on CD8+CTL functions. Culture of CD8+ T cells with IL-12 resulted in the augmentation of IFN-gamma production and cytotoxicity. Moreover, culture of tumor-infiltrating lymphocytes with IL-12 caused a marked enhancement of CD8+CTL against autologous tumor cells. These findings suggest that IL-12 will become a useful cytokine for the tumor immunotherapy. In this paper, we will discuss the key role of CD4+ T cells for the induction of antitumor immunity in tumor-bearing host.

CD4-Positive T-Lymphocytes↗

PubMed1994

[Assessment of osteoporosis in the local population by means of a portable dual energy X-ray absorptiometry unit].

We assessed bone mineral density (BMD) in the local population by means of a portable dual energy X-ray absorptiometry (DXA) unit. BMD was measured by DXA in 197 women (62 premenopausal and 135 postmenopausal) in Shiunji town. Age, height, weight, body mass index (BMI), menstrual history, obstetric history, habits, symptoms and hormonal cytology (eosinophilic index (EI), karyopyknotic index (KPI) and maturation value (MV)) were investigated. A negative correlation (r = -0.645, p < 0.01) was found between BMD and age. Low BMD (BMD < 0.8g/cm2) was found at a rate of 3.2% in premenopausal women and 51.1% in postmenopausal women. The low BMD group of postmenopausal women had significantly lower BMI and higher age at first delivery than the normal BMD group (BMD > or = 0.8g/cm2). There were no differences between the 2 groups in other factors. We found a positive correlation between BMD and hormonal cytology (KPI and MV). These findings suggest that the rate of osteopenia in postmenopausal women is high than expectation and it is difficult to predict bone loss by symptoms, history and habits. The portable DXA unit is useful for screening osteopenia in local populations.

Absorptiometry, Photon↗

PubMed1993

In vitro thermogenic activity of rat brown adipose tissue in neonatal period.

The roles of noradrenaline (NA) and glucagon in ontogeny of nonshivering thermogenesis (NST) were investigated in rats. The relative brown adipose tissue (BAT) mass to body weight was larger in the neonates compared with those of adult animals. The NA level in BAT was low at birth and then increased rapidly to adult level, whereas glucagon level at birth was as high as that in the adult. The thermogenic function of BAT was estimated by measuring the in vitro oxygen consumption of the tissue blocks. NA and glucagon stimulated the oxygen consumption of BAT maximally in a dose of 1 microgram/ml, respectively. The response of the tissue to NA from the neonates just after birth was high compared with that in adult animals. The high values persisted throughout the early neonatal period, and decreased around the weaning period. The response to glucagon exhibited similar pattern. These results indicate that glucagon as well as NA play a significant role in NST in BAT during the early stage of neonatal period.

Adipose Tissue, Brown↗

PubMed1992

Effects of chronic administration of noradrenaline and glucagon on in vitro brown adipose tissue thermogenesis.

The in vitro brown adipose tissue (BAT) oxygen consumption stimulated by noradrenaline (NA) or glucagon (G) was significantly lower in chronically NA-treated rats and that of G-treated rats did not differ as compared with that of vehicle-treated control animals. In vitro thermogenic response of BAT in NA-treated rats was consistent with that induced by cold acclimation.

Acclimatization↗

PubMed1992

Effect of immobilization stress on in vitro and in vivo thermogenesis of brown adipose tissue.

Repetitive intermittent stress such as immobilization has been shown to induce an improved cold tolerance through an enhanced capacity of nonshivering thermogenesis (NST), causing positive cross adaptation between nonthermal stress and cold. In the present study, effect of 3-h-daily immobilization stress for 4-5 weeks was investigated on in vitro and in vivo thermogenesis of interscapular brown adipose tissue (BAT). In vitro thermogenesis was measured in the minced tissue blocks incubated in Krebs-Ringer phosphate buffer with glucose and albumin at 37 degrees C, using a Clark-type oxygen electrode. The stressed rats showed less body weight gain during the experiment. The BAT weight, its protein and DNA contents were significantly greater in the stressed rats. Basal, noradrenaline- and glucagon-stimulated oxygen consumptions were significantly greater in the stressed rats. In vivo thermogenesis was assessed by the changes of temperatures in colon (Tcol), BAT (TBAT), and tail skin (Tsk) induced by noradrenaline or glucagon infusion in the anesthetized rats. Noradrenaline and glucagon increased the TBAT and the extent of increase was greater in the stressed rats. These results indicate that cross adaptation between nonthermal stress and cold may be mediated through an enhanced thermogenic activity of BAT.

Acclimatization↗

PubMed1992

[A case of primary alveolar hypoventilation syndrome with a good response to nocturnal low-flow oxygen inhalation and negative pressure ventilation].

A 34-year-old female was admitted on June 25, 1990, for the evaluation of alveolar hypoventilation which worsened after her second delivery. She showed impairment of both hypercapnic and hypoxic ventilatory responses, and marked desaturation due to hypopnea and apnea during sleep. Although administration of methylxanthine and medroxyprogesterone was not very effective, after treatment with low flow oxygen, there was a marked decrease in the frequency and duration of desaturation during sleep and improvement of arterial daytime blood gases, which suggested the existence of hypoxic ventilatory depression in the pathophysiology of her nocturnal desaturation. Furthermore, the use of a negative pressure ventilator for 3 hours in the daytime for 10 days resulted in marked improvement of symptoms, arterial blood gases, respiratory muscle strength, and the frequency and duration of sleep desaturation. These findings suggest that both low flow oxygen therapy during sleep, and daytime negative pressure ventilation may be beneficial in patients with primary alveolar hypoventilation and central sleep apnea syndrome.

Adult↗

PubMed1991

[A case of agranulocytosis and jaundice due to cellulitis caused by insect bite].

A 58-year-old female was introduced to our hospital for admission on April 22, 1988, because of high grade fever and agranulocytosis. She had eschers on her left zygomatic region and medial region of the right thigh. The latter lesion was accompanied by cellulitis. Laboratory tests showed her WBC was 600/mm3 and T-Bil was 6.51 mg/dl. By using minocyclin, piperacillin and other drugs, her general condition and laboratory data became better in a few days. Although her skin lesions resembled "Tsutsugamushi disease", serological tests showed no evidence for Rickettia infection. So we could not rule out that another kind of insect bite may also develop such a severe clinical course. Furthermore, Staphylococcus aureus or Clostridium spp., which were detected in her pus, might have the toxic effects of inducing agranulocytosis, which might mainly be the result from the local WBC emigration, and jaundice, just like the effects of the endotoxin of Gram negative bacteria.

Agranulocytosis↗

PubMed1991

Brown adipose tissue cell respiration in hypo- and hyperthyroidism after stimulation with selective and non selective beta-adrenergic agonists.

Brown adipocyte respiration was measured in isolated cells from hypothyroid, hyperthyroid and euthyroid Sprague-Dawley male rats. Hypothyroidism was induced by providing drinking water containing methimazole and hyperthyroidism was induced by addition of thyroid powder to the diet. Brown adipose tissue (BAT) cells were isolated by collagenase digestion and oxygen consumption (VO2) was measured by Clark type oxygen electrodes. BAT cell respiration was stimulated by selective and nonselective beta-adrenergic agonists: BRL 35135A (BRL) and Isoprenaline (ISO). Basal BAT cells respiration did not differ according to thyroid status. Maximal VO2 responses of BAT adipocytes from hypothyroid rats were significantly lower than in euthyroidism after ISO and BRL. The reduced response was more marked for ISO than for BRL. The thermogenic sensitivity was significantly greater in euthyroid than is hypothyroid cells for ISO, but not for BRL. The euthyroid-hyperthyroid differences were not significantly different. These results suggest: basal respiration of BAT cells in hypo- and hyperthyroidism does not reflect the overall changes in whole body metabolism; the decreased thermogenic response in hypothyroidism might be due to decreased beta-adrenoceptor numbers and/or decreased intracellular thyroxine-triiodothyronine conversion; changes in sensitivity to ISO and BRL in vitro reflect the changes seen in VO2 in vivo.

Adipose Tissue, Brown↗

PubMed1990

A new apparatus for hair regrowth in male-pattern baldness.

A newly devised apparatus (Scalp-Tension-Relaxer, STR) can efficiently promote hair regrowth in patients with male-pattern baldness. When this apparatus is applied, the scalp is pushed up to relieve tension on the vertex. The efficacy rate of hair regrowth in alopecia patients was 40%. An investigation into the basis for the hair regrowth caused by this apparatus was directed toward the changes in hemodynamics and skin temperature of the scalp. During and after use of this apparatus, subjects exhibited an increase both in the cutaneous blood flow rate (as determined by laser Doppler flowmetry) and in the cutaneous temperature (as determined by thermography).

Adult↗

PubMed1990

Stable and lipophilic technetium-99m dithiosemicarbazone complexes with 5-6-5 membered chelate ring structure.

Modification of the chelate ring structure of technetium-99m (99mTc) dithiosemicarbazone (DTS) chelate was carried out in pursuit of a more stable and lipophilic compound. A new DTS chelating molecule, pentane-2,4-dione bis(N-methylthiosemicarbazone) (PETS), with a 5-6-5 membered chelate ring structure, was synthesized and labeled with 99mTc, PETS generated two 99mTc compounds as major products. Both had much higher stability and lipophilicity than a 5-5-5 membered 99mTc DTS compound, as well as great stability in plasma. Both 99mTc-PETS compounds were rapidly extracted by the brain and heart when injected into mice. Thus, the modified chelate ring structure afforded a preferable characteristics to DTS chelate as for the chelating site for technetium radiopharmaceuticals.

Animals↗

PubMed1990

Changes in fasting-induced adrenocortical secretion of cold-acclimated rats.

Effect of cold acclimation on fasting-induced adrenocortical and metabolic responses was studied in rats. The animals were acclimated to cold by exposure to 5 degrees C for 4 weeks. The warm control animals were kept at 25 degrees C for the same period. Fasting for 48 h decreased the body weight to the same extent in warm controls (WC) and cold-acclimated rats (CA). Plasma free fatty acids concentration increased by fasting, but the degree of increase did not differ between WC and CA. Plasma glucose level decreased in WC, while it increased in CA by fasting. Plasma corticosterone level was significantly higher in CA than in WC. Fasting increased the level in both groups, and the extent of increase as assessed by 95% confidence interval was significantly greater in CA as compared with that in WC. The present results indicate that fasting-induced glucocorticoid secretion is potentiated by cold acclimation, suggesting a possible role of this hormone in some metabolic changes in fasting.

Acclimatization↗

PubMed1990

Training effects on blood zinc levels in humans.

Effects of physical training on fasting erythrocyte and plasma zinc distributions were studied on seven previously sedentary male students. The training consisted of running over 5 km, 6 times/week for 10 weeks. Maximum aerobic capacity (VO2max) and 12 min walk-run performance increased significantly (p less than 0.01) after training. The erythrocyte concentrations of total zinc and of zinc derived from carbonic anhydrase I (CA-I) rose significantly (p less than 0.05) after training, whereas no such effects were noted in CA-II-derived zinc, Cu2Zn2 superoxide dismutase-derived zinc, and other zinc. On the other hand, no effect of training was found in total or alpha 2-macroglobulin-bound zinc in plasma, although albumin-bound zinc concentration declined significantly (p less than 0.05). Following the training period, however, the response to a VO2max test of the van Beaumont quotient (J Appl Physiol 1973;34:102-6) for total plasma zinc had decreased significantly (p less than 0.05), suggesting a relative reduction of the circulating exchangeable zinc. In addition, there were significant (p less than 0.05) decreases in plasma iron and ferritin concentrations after training, indicating latent iron deficiency anemia. These results may suggest that the changes in CA-I-derived zinc and/or albumin-bound zinc portend zinc deficiency during running training and that sports anemia precedes hypozincemia in athletes.

Adolescent↗

PubMed1989

Metabolic cold acclimation after repetitive intermittent cold exposure in rat.

Repetitive intermittent cold exposure (5 degrees C, 6 h/day, 4 weeks) (ICE) resulted in the same cold adaptability as assessed by an enhanced cold tolerance (less drop of colonic temperature at -5 degrees C) and nonshivering thermogenesis (NST) (greater noradrenaline-induced heat production) as that elicited by continuous cold exposure (5 degrees C, 4 weeks) (CA) in rats. Although shorter intermittent (5 degrees C, 2 h/day, 4 weeks) (ICE-2 hr) as well as shorter continuous (5 degrees C, 1 week) (CA-1 wk) cold exposure effected an improved cold adaptability, the magnitude of cold tolerance and NST was smaller as compared with that in CA and ICE. The cold deacclimation process as reflected on the decreased NST did not differ between CA and ICE. Food intake was less in ICE than CA, while increase in body weight during the acclimation period was greater in the former. Increase in adrenal weight was greater in CA than ICE, but plasma corticosterone level did not differ among warm controls (WC), CA, and ICE in resting state (after 18-20 h at warm control temperature of 25 degrees C). Weights of interscapular and dorsocervical brown adipose tissue (BAT) increased to the same degree in CA and ICE. Plasma glucagon level in resting state did not differ among groups, while BAT glucagon levels significantly increased in CA and ICE, but they were higher in dorsocervical site than interscapular site in all acclimated states. Acute cold exposure (-5 degrees C, 15 min) caused increases in plasma corticosterone, glucagon levels, and in BAT glucagon levels in all acclimated groups. The extent of increase was significantly less for plasma glucagon in CA, while plasma corticosterone increased similarly in all groups. These results indicate that repetitive short-term cold exposure could elicit the same cold adaptability as that induced by continuous exposure, but requiring only one-fourth of the time of continuous cold exposure. Moreover, it is suggested that glucagon is involved in both CA and ICE, but the same extent of cold adaptability can be obtained in the less energy-requiring and less stressful state in ICE.

Acclimatization↗