PubMed Health⌕ Search

Biomedical subjects

T Seto

Publications and source records attributed to T Seto.

At least 55 records · Page 3Linked to original sources
PubMed1998

[Auditory brainstem responses (ABR) in patients with Wolfram syndrome].

Auditory brainstem responses (ABR) and other evoked potentials were studied in four patients with the Wolfram syndrome. In three cases ABR was abnormal in the early stage of the disease. There was no responses or only the wave V with prolonged latency at a stimulation level of 80 dBnHL. A prolongation of the I-V interpeak latency (IPL) was also revealed at a stimulation level of 105 dBnHL. The remaining patient showed shortening of the I-V IPL. The visual evoked potentials showed prolonged peak latency in three cases, and the median nerve short latency somatosensory evoked potentials were normal in two cases. These ABR findings indicated not only sensory neuronal hearing loss but also a degenerative change in the brain stem in the Wolfram syndrome.

Adolescent↗
PubMed1997

Inhibition of Na+,K(+)-ATPase by 1,2,3,4,6-penta-O-galloyl-beta-D-glucose, a major constituent of both moutan cortex and Paeoniae radix.

The inhibition of Na+,K(+)-ATPase activity by various constituents of Moutan Cortex and Paeoniae Radix was studied. 1,2,3,4,6-Penta-O-galloyl-beta-D-glucose (PGG), a major component of both crude drugs, strongly inhibited Na+,K(+)-ATPase activity (IC50 = 2.5 x 10(-6) M), whereas galloylpaeoniflorin, benzoic acid, and catechin were weakly inhibitory, and albiflorin, oxypaeoniflorin, paeoniflorin, paconol, and phenol were ineffective. The inhibition of Na+,K(+)-ATPase activity by PGG was decreased in the presence of BSA or phospholipids. The inhibition mode of PGG was noncompetitive with respect to ATP. The K0.5 value for Na+ was increased by the addition of PGG from 9.1 to 12.3 mM, whereas that for K+ was not altered. PGG also inhibited K(+)-dependent p-nitrophenyl phosphatase activity with an IC50 value of 5.3 x 10(-6) M, and the extent of the inhibition increased at higher concentrations of K+. The K0.5 value for K+ was decreased by the addition of PGG from 3.3 to 2.0 mM. These results suggested that the inhibition of Na+,K(+)-ATPase activity is caused by interaction of PGG with the enzyme in the E2 state. The inhibitory effect of Moutan Cortex or Paeoniae Radix is considered to be mainly attributable to PGG.

4-Nitrophenylphosphatase↗
PubMed1997

Involvement of central neurotensin in thermoregulatory and neuroimmune function in pregnant rats exposed to heat.

To examine a functional relationship among pregnancy and central neurotensin and thermoregulatory and neuroimmune systems during heat stress, we monitored colonic temperature in six virgin female rats and six pregnant rats (9 to 11 days gestation) exposed to a microwave source. We also assayed splenic natural killer cell activity (NKCA), blood corticosterone (CS), and ACTH as indicators of the hypothalamic-pituitary-adrenal axis, beta-endorphin (beta-EP), and neurotensin (NT) in discrete brain regions. Additionally, we clarified the effects of intracerebroventricular (icv) administration of NT antiserum on these same responses in pregnant rats exposed to heat stress. Repeated-measures analysis of variance showed significant main effects of heat and pregnancy and a significant interactive effect on colonic temperature. Significant elevation in blood CS, ACTH, beta-EP, and NT in the hypothalamus and significant reductions in splenic NKCA and NT in the nucleus accumbens were produced by heat. In the experiment examining the effect of icv administration of NT antiserum, significant main effects of heat and administration and a significant interactive effect on colonic temperature were observed. Icv administration of NT antiserum increased splenic NKCA and decreased blood beta-EP. These results show that pregnancy enhances thermal homeostasis, suggesting central thermoregulatory mechanisms through NT in nucleus accumbens and hypothalamus in which placental or pituitary beta-EP may be involved. NT and beta-EP seem to play central roles simultaneously in heat-induced immunosuppression during pregnancy. Clarification for the effects of NT antiserum on beta-EP in virgin rats or manipulation of agents related to opioid system should be the focus of future work.

Adrenocorticotropic Hormone↗
PubMed1997

Inhibitory effect of pregnancy on stress-induced immunosuppression through corticotropin releasing hormone (CRH) and dopaminergic systems.

To clarify the involvement of pregnancy in the response of the neuroendocrine-immune system to stress, we examined splenic natural killer-cell-activity-(NKCA) and its relevant central and blood parameters in female virgin and pregnant rats (10 to 11 days gestation) exposed to forced water-immersion stress with durations of 90 min and 180 min. Decreases in splenic NKCA, corticotropin releasing hormone (CRH) in the hypothalamus, and increases in progesterone (P), beta-endorphin (beta EP), and dopamine (DA) metabolic ratios in the frontal cortex and nucleus accumbens produced by stress were recognized in the virgin rats, but not in the pregnant rats. Pregnancy reduced splenic NKCA in rats without stress, but elevated it in the rats exposed to stress with a duration of 180 min. These findings suggest inhibitory effects of pregnancy on stress-induced immunosuppression and neuroendocrine changes, thereby promoting homeostasis in the neuroendocrine-immune system against stress. Such enhanced homeostasis associated with pregnancy seemed to be mediated by the activation of placental P and placental or pituitary beta EP in cooperation with mesocortical and mesolimbic DA systems and hypothalamic CRH.

Animals↗
PubMed1997

Effect on prognosis of bone marrow infiltration detected by magnetic resonance imaging in small cell lung cancer.

The staging system of limited disease (LD) and extensive disease (ED) is widely used and has been shown to provide useful prognostic information in cases of small cell lung cancer (SCLC). However, accurate examinations are necessary for correct staging. In this report, we evaluated the clinical usefulness of magnetic resonance imaging (MRI) of bone marrow in SCLC. 37 patients with LD by standard staging and 41 with ED were examined with bone marrow MRI. Results of bone marrow MRI did not influence the choice of treatment in patients with LD. For subsequent analysis, patients with LD were divided into two groups: patients in whom bone marrow infiltration was detected with MRI (MRI-positive LD group) and those in whom it was not (MRI-negative LD group). Focal or diffuse metastases to bone marrow were detected with MRI in 46% (36/78) of all patients and 35% (13/37) of LD patients. The response rates to treatment in patients with MRI-positive LD were lower than those in patients with MRI-negative LD (P = 0.006). The survival of patients with MRI-positive LD was worse than that of MRI-negative LD (generalised Wilcoxon test: P = 0.0157), and closer to that of ED. Multivariate analyses using a Cox model that included the result of bone marrow MRI, performance status, chemotherapy regimen, radiotherapy and serum lactose dehydrogenase (LDH) level showed that the result of bone marrow MRI remained a prognostic factor in SCLC patients with limited disease. Bone marrow examination with MRI is useful for better staging of SCLC. According to our analysis of response rates and survival, MRI-positive LD should be considered a type of ED.

Bone Marrow Neoplasms↗
PubMed1997

Effect of NS-21, an anticholinergic drug with calcium antagonistic activity, on lower urinary tract function in a rat model of urinary frequency.

BACKGROUND: NS-21 is under development for the treatment of urinary frequency and urinary incontinence. The purpose of this study was to investigate the effects of NS-21 and its active metabolite, RCC-36, on lower urinary tract function in an experimental rat model of urinary frequency. METHODS: Cystometrograms were recorded in anesthetized rats with bilaterally transected hypogastric nerves. All drugs were administered intraduodenally. RESULTS: In sham-operated rats, NS-21 (> or = 50 mg/kg) significantly increased the bladder capacity without significantly decreasing micturition pressure, while RCC-36 (100 mg/kg) significantly increased bladder capacity, and at a dose of > or = 30 mg/kg, also caused a decrease in micturition pressure. This increase in bladder capacity appeared at lower doses of both NS-21 and RCC-36 in the hypogastric nerve-transected rats. Propiverine (100 mg/kg) increased bladder capacity and at > or = 30 mg/kg, decreased micturition pressure in both sham-operated and nerve-transected rats. Oxybutynin (100 mg/kg) and atropine (30 mg/kg) decreased the micturition pressure in both sham-operated and nerve-transected rats without increasing the bladder capacity, while a similar anticholinergic calcium antagonist, terodiline (100 mg/kg) had no effect on bladder capacity in either sham-operated or nerve-transected rats. Flavoxate (500 mg/kg) significantly increased bladder capacity without significantly decreasing micturition pressure in both sham-operated and nerve-transected rats, while 50 mg/kg of verapamil significantly increased bladder capacity without significantly decreasing the micturition pressure in nerve-transected rats. CONCLUSIONS: NS-21 and RCC-36 increased bladder capacity at lower doses in hypogastric nerve-transected rats than in sham-operated rats. Furthermore, NS-21 increased the bladder capacity without suppressing micturition pressure, suggesting that NS-21 may be a more effective therapeutic drug than propiverine, oxybutynin or flavoxate for the treatment of urinary frequency and urinary incontinence.

Animals↗
PubMed1997

Effects of exposure to microwaves on cellular immunity and placental steroids in pregnant rats.

OBJECTIVES: Microwaves produce various detrimental changes based on actions of heat or non-specific stress, although the effects of microwaves on pregnant organisms has not been uniform. This study was designed to clarify the effect of exposure to microwaves during pregnancy on endocrine and immune functions. METHODS: Natural killer cell activity and natural killer cell subsets in the spleen were measured, as well as some endocrine indicators in blood--corticosterone and adrenocorticotrophic hormone (ACTH) as indices of the hypothalamic-pituitary-adrenal axis--beta-endorphin, oestradiol, and progesterone in six female virgin rats and six pregnant rats (nine to 11 days gestation) exposed to microwaves at 10 mW/cm2 incident power density at 2450 MHz for 90 minutes. The same measurements were performed in control rats (six virgin and six pregnant rats). RESULTS: Skin temperature in virgin and pregnant rats increased immediately after exposure to microwaves. Although splenic activity of natural killer cells and any of the subset populations identified by the monoclonal antibodies CD16 and CD57 did not differ in virgin rats with or without exposure to microwaves, pregnant rats exposed to microwaves showed a significant reduction of splenic activity of natural killer cells and CD16+CD57-. Although corticosterone and ACTH increased, and oestradiol decreased in exposed virgin and pregnant rats, microwaves produced significant increases in beta-endorphin and progesterone only in pregnant rats. CONCLUSIONS: Microwaves at the power of 10 mW/cm2 produced activation of the hypothalamic-pituitary-adrenal axis and increased oestradiol in both virgin and pregnant rats, suggesting that microwaves greatly stress pregnant organisms. These findings in pregnant rats suggest that--with exposure to microwaves--pregnancy induces immunosuppression, which could result in successful maintainance of pregnancy. This enhancement of adaptability to heat stress with pregnancy may be mediated by activation of placental progesterone and placental or pituitary beta-endorphin.

Adrenocorticotropic Hormone↗
PubMed1997

Efficient isolation of subacute sclerosing panencephalitis virus from patient brains by reference to magnetic resonance and computed tomographic images.

Subacute sclerosing panencephalitis virus has been isolated with difficulty from brains of infected patients. More strains are needed for the study of the pathogenesis of this virus. To make the isolation more efficient, we selected portions to be examined from the brains of three patients with reference to findings of repeated magnetic resonance and computed tomographic imaging. Three cell lines susceptible to measles virus field strains were used. In all three cases viruses were isolated most effectively from recent lesions and with Vero cells. Our results suggested that these imaging methods and Vero cells could be used for improvement in the efficiency of isolation of this virus from patient brains.

Adult↗
PubMed1997

Primary intracranial germ cell tumors: a clinical analysis of 153 histologically verified cases.

The authors analyzed 153 cases of histologically verified intracranial germ cell tumors. The histological diagnosis was germinoma in 63 patients (41.2%), teratoma in 30 (19.6%), and other types of tumors in 60 patients (39.2%). The patients were treated by a consistent policy of surgical removal with histological verification followed by radiation therapy with or without chemotherapy. The 10- and 20-year survival rates of patients with pure germinoma were 92.7% and 80.6%, respectively. The 10-year survival rates of patients with mature teratoma and malignant teratoma were 92.9% and 70.7%, respectively. Patients with pure malignant germ cell tumors (embryonal carcinoma, yolk sac tumor, or choriocarcinoma) had a 3-year survival rate of 27.3%. The mixed tumors were divided into three subgroups: 1) mixed germinoma and teratoma; 2) mixed tumors whose predominant characteristics were germinoma or teratoma combined with some elements of pure malignant tumors; and 3) mixed tumors with predominantly pure malignant elements. The 3-year survival rates were 94.1% for the first group, 70% for the second group, and 9.3% for the third group, and the differences were statistically significant. Twenty-six patients with malignant tumors received chemotherapy that consisted of cisplatin and carboplatin combinations with or without radiation therapy. However, chemotherapy was not significantly more effective than radiation therapy alone. From these treatment results, the authors classified tumors into three groups with different prognoses and proposed a treatment guideline appropriate for the subgroups.

Adolescent↗
PubMed1997

[Inhibitory effect of isosorbide dinitrate on whole blood aggregation].

Isosorbide dinitrate (ISDN) has an inhibitory effect on platelet aggregation through the generation of nitric oxide (NO). We examined the effect of ISDN on whole blood aggregation using an impedance aggregometer. Blood samples were obtained from 16 patients with acute myocardial infarction and 4 patients with angina pectoris before and after an intravenous administration of ISDN during coronary arteriography. Whole blood obtained from normal healthy donors was used for an in vitro study. Whole blood aggregation after administration of ISDN was significantly inhibited compared to that before administration (36.1 +/- 8.3 vs 43.7 +/- 8.4 omega, p < 0.001), and cyclic guanine monophosphate (c-GMP) concentration increased (5.56 +/- 2.0 vs 5.14 +/- 1.86 p mol/ml, p < 0.05). The inhibitory effect of ISDN was also observed in the in vitro study, in which the effective concentration of ISDN corresponded to the blood level of ISDN (> or = 10(-7) mol) in the clinical setting. The inhibitory effect of ISDN was diminished by the addition of methylene blue or NG-monomethyl-L-arginine monoacetate in the exo vivo and in vitro studies. The concentration of c-GMP was increased by the addition of ISDN to platelets and white blood cell suspended plasma compared to the control (1.93 +/- 0.50 vs 1.77 +/- 0.42 p mol/ml, p < 0.05), but there was no significant difference when ISDN was added to platelet-rich plasma. These results suggest that ISDN inhibits whole blood aggregation through NO generation and white blood cells are important in the mechanism of ISDN action.

Angina Pectoris↗
PubMed1996

[Estimation and control measures for environmental tobacco smoke in an office].

The aim of this study is to evaluate the air pollution due to smoking in an office where no smoking control measures have been adopted. The concentration of suspended particulates (SP) at 8 points in this office were measured and the change of SP concentrations at 3 points were recorded for 24 hours. The results show that the main source of SP is tobacco smoke in the office. Smoking control measures should be promoted in such offices where smokers and non-smokers work together. The effectiveness of a ventilation system and practical smoking control measures are discussed.

Air Pollution, Indoor↗
PubMed1996

Dynamic Small-Angle X-ray Scattering System using an Imaging Plate.

A synchrotron-radiation dynamic small-angle X-ray scattering (Synchrotron Radiation-DSAXS) system using an imaging plate has been developed at the Photon Factory, National Laboratory for High Energy Physics, Japan, in collaboration with the Department of Polymer Chemistry, Kyoto University, Japan, for studying the dynamic response of mesoscopic structures in polymers to applied mechanical stimuli. Small-angle X-ray scattering patterns of 100 x 100 mm(2) have been successively recorded on a 400 x 200 mm(2) stage-mounted imaging plate with a minimum time interval of 0.5 s. X-ray data are simultaneously obtained with stress and strain measurements on specimens subjected to a mechanical deformation. The performance of the DSAXS system is demonstrated along with some experimental results concerning the dynamic deformation of a b.c.c. lattice with paracrystalline distortion in a co-polymer having spherical microdomains under a large oscillatory shear deformation.

Journal Article↗
PubMed1996

Enzymatic synthesis of 4-O-beta-D-galactopyranosyl-moranoline and 3-O-beta-D-galactopyranosyl-moranoline by using beta-galactosidase from Bacillus circulans.

A transgalactosylation reaction from lactose to moranoline (1-deoxynojirimycin) was accomplished by using beta-galactosidase [EC 3.2.1.23] from Bacillus circulans. The enzyme formed 3-O-beta-D-galactopyranosyl-moranoline and 4-O-beta-D-galactopyranosyl-moranoline as major products, together with 2-O-beta-D-galactopyranosyl-moranoline and 6-O-beta-D-galactopyranosyl-moranoline as minor ones.

1-Deoxynojirimycin↗
PubMed1996

[Pharmacokinetics of propofol during liver transplantation in small pigs].

A study using 14C propofol showed that the liver is the main eliminating organ for the agent. The current study was designed to clarify pharmacokinetics of propofol during liver transplantation in pigs. Five small pigs weighing 25.4 +/- 2.5 kg were anesthetized with isoflurane (0.5-1.5%) and mechanically ventilated under muscle paralysis with pancuronium. In the anhepatic phase, veno-veno bypass was placed from the inferior vena cava and portal vein to the superior vena cava. We studied pharmacokinetic parameters following an intravenous bolus injection of propofol at 2 mg.kg-1 in each phase, i.e. the pre-anhepatic, anhepatic and post-anhepatic phase during liver transplantation. Pharmacokinetic analysis showed that total plasma clearance of propofol in the anhepatic phase was significantly lower than that in the post-anhepatic phase. The results suggest that propofol may be metabolized extrahepatically and can be used at reduced doses in the anhepatic phase during liver transplantation.

Anesthetics, Intravenous↗
PubMed1996

[Thoracoscopy with two bronchoscopes in 50 patients with pleural effusion of unknown origin].

When performing thoracoscopy in patients with pleural effusion of unknown origin, we used two bronchoscopes simultaneously, one for observation and one for biopsy. A total of 50 patients with pleural effusion of unknown origin were studied. In all of those studies, pleural effusion was exudative, lymphocyte-dominant, had a low level of adenosine deaminase, no malignant cells, and no tuberculosis or other bacteria in pleural effusion smears. Fourteen were out-patients. A catheter was inserted into the pleural space under local anesthesia, and 300 ml to 500 ml of pure oxygen was injected to create a pneumothorax. Two flexible fiberoptic bronchoscopes were used simultaneously, one for observation and one for biopsy. Approximately 1 hour after the examination, the out patients were able to return home. Lesions in the pleural cavity were found in 42 of these 50 patients, and histological diagnosis was possible in 46. This is a simple procedure with no major side effects. The equipment required is familiar to pulmonary physicians, and the diagnostic yield is high.

Adult↗
PubMed1995

Masseter muscle activity and the hypoglossal nerve.

The effects of severing the hypoglossal nerve and resultant restriction of tongue movement was evaluated for its effect on masticatory jaw movement. Electromyograms of masseter muscles in the feeding rat were recorded 3 days after the nerve severing operation at 1 week intervals. Even after severing the lateral branches of the hypoglossal nerve bilaterally, active-feeding behaviour continued with mastication slightly impaired. After severing the medical branches bilaterally, feeding behaviour was rarely observed, but where eating did take place mastication was impaired with marked disturbance in the masticatory rhythm.

Animals↗
PubMed1995

[Endocrine mechanism of placental circulatory disturbances induced by microwave in pregnant rats].

Effects of microwaves on fetus and female genital organs remain to be elucidated. To demonstrate the placental circulatory disturbances induced by microwaves and to clarify the endocrine pathogenesis, placental blood flow and five endocrine indicators, i.e., corticosterone (CS), estradiol (E2), progesterone (P), prostaglandin E2 (PGE2) and prostaglandin F2 alpha (PGF2 alpha) were measured in rats exposed to whole-body microwaves with an intensity of 10 mW/cm2 at a frequency of 2,450 MHz. The placental blood flow at 45-90 min after exposure was significantly decreased in the rats exposed to the microwaves. Placental blood flow at 15 and 30 min was increased by pretreatment with intraperitoneal administration of angiotensin II (AII). In contrast, no significant change in placental blood flow was recognized in the AII pretreated rats exposed to the microwaves. An increase in CS and a decrease in E2 were induced by the microwave exposure independent of pretreatment with AII. P was increased by microwave exposure in the rats without pretreatment with AII. PGE2 was not changed by the microwave exposure in the case of either nonpretreatment or pretreatment with AII. PGF2 alpha was increased by the microwave exposure in the rats without pretreatment with AII. The present results indicate that excessive exposure to whole-body microwave disorders pregnancy in terms of placental circulatory dysfunction. The data suggest the involvement of endocrine mechanisms in the decrease in placental blood flow which is induced via a detrimental effect of microwaves on PGF2 alpha and on pituitary functions such as general emotional stress.

Angiotensin II↗