Biomedical subjects

T Seto

Publications and source records attributed to T Seto.

At least 37 records · Page 2Linked to original sources

PubMed2000

The inhibition of phenylhydroquinone-induced oxidative DNA cleavage by constituents of Moutan Cortex and Paeoniae Radix.

Moutan Cortex (root cortex of Paeonia suffruticosa ANDREWS) and Paeoniae Radix (root of Paeonia lactiflora PALLAS) are crude drugs used in many traditional prescriptions and have constituents in common. We studied the effects of extracts of these crude drugs and their constituents on oxidative DNA damage caused by phenylhydroquinone (PHQ), a major metabolite of o-phenylphenol. Both drugs suppressed the cleavage of pUC18 DNA induced by PHQ, and scavenged the superoxide and hydroxy radical generated by the chemical. They also inhibited the oxidative DNA cleavage by tert-butylhydroquinone (TBHQ), one of the major metabolites of butylated hydroxyanisole. When constituents were examined with the same system, galloylpaeoniflorin and 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (PGG) were found to be the most potent inhibitors of the DNA cleavage. These constituents had oxygen radical scavenging activity. Paeonol also attenuated the DNA cleavage. Paeoniflorin and albiflorin had relatively small inhibitory effects on DNA cleavage. However, catechin enhanced the PHQ-induced DNA cleavage. The suppression of oxidative DNA damage by Moutan Cortex and Paeoniae Radix might be attributable to the additive effects of galloylpaeoniflorin, PGG and other constituents.

Biphenyl Compounds↗

PubMed2000

Microbial contamination of in-use lubricants for non-touch urethral catheters in intermittent self-catheterization.

There are no reports on microbial contamination of repeatedly used lubricant (84-87% glycerin containing 0.02% benzalkonium chloride) for non-touch urethral catheters in intermittent self-catheterization. In this work, we evaluated microbial contamination of in-use lubricant and its prevention. Between September and December, 1996, microbial contamination and water activity of in-use lubricants in sheathed and lubricated non-touch catheters connected to a tube used by 46 outpatients at our hospital was examined. Microbial contamination was detected at 5 to 2.6 x 10(8) colony-forming units (CFU)/ml in 14 (30.4%) of 46 samples. With higher water activity of the lubricant (a higher dilution rate of the lubricant with water), a higher concentration of microbial contamination was observed. In 3 (21.4%) of the 14 patients using contaminated lubricant, urine samples showed the same microbial species as those detected in the lubricant. To prevent microbial contamination of the lubricant, dilution of the lubricant with water, as a result of repeated use, should be avoided.

Bacteria↗

PubMed2000

[The effective smoking corner in an office].

We installed an effective, practical and low-cost smoking corner in an office to protect against passive smoking. The smoking corner was separated from the non-smoking area with transparent, nonflammable screens. Four exhaust fans were installed in the smoking corner so that there was no leakage of environmental tobacco smoke. The required exhaust air rate in the smoking corner was pre-calculated from the volume of the smoking corner and the rate of consumption of cigarettes. The suspended airborne particle concentration definitely decreased in the non-smoking area after installation of the smoking corner. The result of a questionnaire survey also revealed the improvement in the air quality in this office.

Air Pollutants, Occupational↗

PubMed2000

[A long-term survivor of extensive-stage small cell lung cancer].

A 53-year-old man was admitted for evaluation of multiple hepatic tumors. A thoracic CT scan revealed a mass lesion in the right middle lobe. Transcutaneous needle aspiration cytology from the lung tumor and transcutaneous hepatic tumor biopsy were performed, from which the cytohistological diagnosis was small cell lung cancer with liver metastasis. The patient was treated with 3 courses of high dose cisplatin with vindesine and mitomycin and 5 courses of carboplatin with etoposide, and achieved a complete response. We herein report a long-term survivor of extensive-stage small cell lung cancer.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2000

[Depression of serum pyridoxal levels in theophylline-related seizures].

In order to study whether a theophylline-related seizure is caused by a decrease in serum vitamin B6, serum pyridoxal (PAL) levels were measured in children with bronchial asthma treated with theophylline. The serum PAL levels of asthmatic children (n = 31) treated with theophylline were significantly lower than those of control subjects (n = 21). Moreover, we evaluated PAL levels in four subjects within twenty-four hours after a seizure with or without fever. The level was low in three of the four. These results suggest that the decrease in PAL levels caused by theophylline may lower the seizure threshold.

Adolescent↗

PubMed1999

Relationship between urinary cadmium and mortality among inhabitants living in a cadmium polluted area in Japan.

A 15 year follow-up study of 3119 inhabitants living in a cadmium polluted area was conducted to investigate the influence of environmental cadmium exposure on the mortality. The cumulative survival curves of the subjects with urinary cadmium concentration > or = 10 microg/g creatinine was lower than that of the subjects with < 10 microg/g creatinine in the men aged 50-59 and 60-69 years and in the women aged 60-69 and 70-79 years. In the men aged 50-69 years and the all aged women, the cumulative survival curves became lower in proportion to the increase of urinary cadmium concentration, when the subjects were divided into four groups according to the amount of urinary cadmium concentration (< 5, 5-9.9, 10.1-19.9, > or = 20 microg/g creatinine). These results suggested a dose response relationship between cadmium exposure and mortality.

Aged↗

PubMed1999

Platelet membrane fluidity individuals at risk for Alzheimer's disease: a comparison of results from fluorescence spectroscopy and electron spin resonance spectroscopy.

RATIONALE: Previous fluorescence studies employing 1,6-diphenyl-1,3,5-hexatriene (DPH) have revealed an increase in the fluidity of platelet membranes from individuals with Alzheimer's disease (AD) and their first-degree relatives. This biophysical alteration has been reported to be relatively specific for the hydrocarbon core of platelet membranes, where DPH preferentially localizes; this effect is not reflected by the fluorescent reporter triethylamino-DPH, which labels membranes at the lipid-aqueous interface. OBJECTIVE: The goal of this study was to explore the validity and reproducibility of these findings using an independent biophysical technique, electron spin resonance (ESR) spectroscopy. METHODS: Platelet membranes prepared from first-degree relatives of patients with AD were labeled with DPH, or the spin-labeled fatty acid probes 5-doxylstearate (5-DS) and 12-doxylstearate (12-DS). These spin labeled probes provide an index of structural order at the respective depths of their nitroxide moieties in the membrane. The resulting preparations were examined by fluorescence and ESR spectroscopy. RESULTS: Increased platelet membrane fluidity (PMF), as determined by the fluorescence anisotropy of DPH, was associated with only a modest reduction in the order parameter derived for 5-DS labeled membranes. In contrast, the mean order parameters derived from the paired samples labeled with 12-DS differed substantially from each other, and revealed decreased order (increased fluidity) in the hydrocarbon 12-C region where DPH preferentially localizes. CONCLUSIONS: These results provide an independent validation of the biophysical alterations of platelet membranes that are manifested by a subgroup of patients with AD and their first-degree relatives.

Adult↗

PubMed1999

Sequential MRI, SPECT and PET in respiratory syncytial virus encephalitis.

We report on a 3-year-old girl with respiratory syncytial virus (RSV) encephalitis manifested by disturbance of consciousness, conjugate eye deviation, anuria, truncal ataxia and intention tremor. T2-weighted magnetic resonance imaging (MRI) showed hyperintense areas in the cerebellar cortex. No lesion was detected in the cerebral cortex, pons or spinal cord. The hyperintense areas in the cerebellar cortex diminished with recovery from the clinical manifestations and had resolved 2 months after onset. The MRI lesions in the cerebellum were considered to be due to oedema. SPECT and positron emission tomography (PET), performed 3 months after onset, disclosed areas of hypoperfusion and hypometabolism at the same sites. One year after onset, MRI showed mild atrophy of the cerebellum. Hypoperfusion on SPECT and hypometabolism on PET remained. Neuroimaging showed that ataxia and tremor in this case were the result of cerebellitis. The patient has no neurological deficit except for mild truncal ataxia. This patient is a rare example of RSV encephalitis.

Brain↗

PubMed1999

Suppressive effects of Hochu-ekki-to, a traditional Chinese medicine, on IgE production and histamine release in mice immunized with ovalbumin.

We examined the effects of Bu-Zhong-Yi-Qi-Tang (Japanese name: Hochu-ekki-to, HET), a traditional Chinese medicine, on IgE production and histamine release in mice immunized intraperitoneally with a mixture of ovalbumin (OA) and aluminum hydroxide (alum adjuvant). Three groups of mice were orally administered 0, 1.7 or 17 mg of HET on day 13 after the first immunization with a mixture of 1 microg OA and 1 mg alum adjuvant. They were again immunized with the same dose of OA plus alum adjuvant on day 14. The immunological changes in mice treated with OA alone or OA plus HET were examined, and the following findings were obtained. In the HET-treated mice, the elevation of anti-OA IgE in serum, and histamine release from basophils in blood, were significantly suppressed. A significant suppression of interleukin-4 (IL-4) secretion and proliferation of splenic lymphocytes in primary culture was also observed. A tendency to suppress the elevation of anti-OA IgG1 in serum and interleukin-2 (IL-2) secretion from splenic lymphocytes was observed in the HET-treated mice. These findings suggest that oral administration of HET suppresses IgE antibody production and histamine release in type I allergic reaction in mice immunized with OA plus alum adjuvant; this shows the efficacy of HET in treating type I allergic diseases, such as asthma.

Animals↗

PubMed1999

[Determination of sennoside A and sennoside B in formulation using capillary electrophoresis].

The determination of sennoside A (SA) and sennoside B (SB) by capillary zone electrophoresis was developed. The separation of SA and SB was performed in 100 mM of the 3-[cyclohexylamino]-1-propanesulfonic acid (CAPS) buffer (pH 10.0), and the migration time of SA and SB was found to be both less than 7 min. This method was applied to the analyses of seven commercial formulations containing SA and SB without previous treatment. The statistical comparison of the results obtained from both capillary electrophoresis and HPLC methods revealed an absolute correlation.

Anthraquinones↗

PubMed1999

In vitro system for immunoglobulin class switching using BHK cells transfected with murine recombinant CD40 ligand.

To develop an in vitro system for mouse immunoglobulin (Ig) class switching, the expression vector of murine CD40 ligand (CD40L) which is expressed on T cells was transfected to BHK cells. By using culture plates coated with the BHK cells expressing the recombinant CD40L, Ig class switching of splenic B cells was examined. The CD40L mRNA was cloned from splenic T cells of BALB/mice activated with anti-CD3 antibody in vitro. As the No.593 base in the open reading frame sequence of the CD40L from BALB/c spleen differed from T to G, when compared with the known sequence from C57BL/6, one of the BALB/c-derived clones was reconstructed to the known CD40L by site-directed mutagenesis. Splenic B cells from BALB/c were induced secretion of Ig isotypes, IgM, IgG1 and IgE when cultured on two types of BHK cells, the transfected BHK cells with a CD40L clone from BALB/c and the transfected BHK cells with the reconstructed CD40L clone, in the presence of IL-4. However, when splenic B cells from C57BL/6 were cultured on the same systems, the B cells produced Ig isotypes, IgM, IgG1, IgG2a, IgG2b, IgG3 and IgE. In the similar experiments using the transfected BHK cells with a empty vector and the normal BHK cells, none of B cells produced any Ig isotypes other than IgM. These results indicate that Ig class switching of murine B cells can be induced by using these two types of CD40L-expressing BHK cells in vitro.

Animals↗

PubMed1999

Different transcriptional expression of the matrix gene of the two sibling viruses of the subacute sclerosing panencephalitis virus (Osaka-2 strain) isolated from a biopsy specimen of patient brain.

Two sibling viruses of the subacute sclerosing panencephalitis (SSPE) virus Osaka-2 strain were isolated from a small biopsy specimen of the brain of an SSPE patient just before intraventricular interferon treatment by cocultivation with two different cell lines, Vero cells or B95a cells (Ogura et al, 1997). Both the virus-infected cells were found to be indistinguishable from each other in defective production of cell-free virus and in defective expression of the matrix (M) protein. The sequence analysis of the M genes predicted that they were translatable due to a lack of alteration of the translational start and stop codons for the proteins. A different pattern of the M monocistronic transcripts, however, was observed in a Northern blot analysis of the infected cells. This different pattern was confirmed further by a primer extension analysis. The undetectable expressions of the M proteins in the sibling virus-infected cells are most probably different in their molecular mechanisms. All these results indicate the possibility that the two different, replicable variants existed at Jabbour stage III of the disease's progression in a very small portion of the brain, where no lesion had yet been recognized by a magnetic resonance imaging.

Amino Acid Sequence↗

PubMed1999

[Primary pulmonary cryptococcosis diagnosed by medical examinations in 12 patients].

Primary pulmonary cryptococcosis is thought to be relatively less common than other lung mycoses, but recently there has been an increase in reports of patients with this disease. Our report covers 12 cases of primary pulmonary cryptococcosis in which the diagnosis was based on medical examinations. The patients consisted of 11 men and 1 woman, aged 27 to 58 years. Only 3 exhibited subjective symptoms. Roentgenograms showed cavitating tumor shadows in the lungs of 2 of the patients with subjective symptoms, and nodular shadows with diameters of 1.0 to 2.8 cm in all patients without subjective symptoms, indicating the possibility of lung cancer. The disease was diagnosed in 3 patients on the basis of transbronchial biopsy findings, and in 9 on the basis of needle aspiration biopsy findings. One patient was diabetic, but the others did not exhibit malignancies or other immunocompromised states. Antifungal drugs significantly reduced or eliminated the nodular shadows in 10 patients. Because patients with primary pulmonary cryptococcosis frequently lack subjective symptoms, prompt diagnosis is critical, particularly in view of the need to distinguish the disease from lung cancer.

Adult↗

PubMed1998

Natural killer cell activity reduced by microwave exposure during pregnancy is mediated by opioid systems.

We have previously demonstrated immunosuppression including reduced splenic natural killer cell activity (NKCA) in pregnant rats exposed to microwaves produced mainly by their thermal action. To examine the involvement of opioid systems in reduced NKCA in pregnant rats exposed to microwaves at a relatively low level (2 mW/cm2 incident power density at 2450 MHz for 90 min), we assayed beta-endorphin (betaEP) in blood, pituitary lobes, and placenta as well as splenic NKCA in virgin and/or pregnant rats. Although microwaves elevated colonic temperatures by 0.8 degreesC for virgin and 0.9 degreesC for pregnant rats, and betaEP in blood and anterior pituitary lobes (AP) significantly, it did not change blood corticosterone as an index of hypothalamic-pituitary adrenal axis. There were significant interactions between pregnancy and microwave exposure on splenic NKCA, betaEP in both blood and AP, and blood progesterone. Intra-peritoneal administration of opioid receptor antagonist naloxone prior to microwave exposure increased NKCA, blood, and placental betaEP in pregnant rats. Alterations in splenic NKCA, betaEP and progesterone in pregnant rats exposed to microwaves may be due to both thermal and nonthermal actions. These results suggest that NKCA reduced by microwaves during pregnancy is mediated by the pituitary opioid system.

Animals↗

PubMed1998

Nucleotide sequences of the matrix protein gene of subacute sclerosing panencephalitis viruses compared with local contemporary isolates from patients with acute measles.

Measles viruses isolated from brain cells of patients with subacute sclerosing panencephalitis (SSPE) have numerous mutations, especially in the matrix protein (M) gene. To find whether the M genes of these SSPE viruses were mutated randomly or in a pattern, we sequenced this gene from three strains of defective measles virus isolated in Osaka, Japan. We could deduce the sequence of the possible progenitor measles virus for each patient by comparison of the isolate with measles viruses prevailing at roughly the same time and place as the primary infection. Biased hypermutation affected the M genes of all three SSPE viruses, although the molecular mechanisms for the mutations might be various. Replacements of U with C in the plus strand accounted for 76% of all mutations in two of the strains, but in the other strain, replacements of A with G accounted for 52% of the mutations, and the U residues were unchanged.

Acute Disease↗

PubMed1998

Central administration of interleukin-1 beta reduces natural killer cell activity in non-pregnant rats, but not in pregnant rats.

To examine responses of natural killer cell activity (NKCA) to interleukin-1 beta (IL-1 beta) during pregnancy, we determined splenic NKCA as well as blood and brain indicators in virgin and pregnant rats (14 or 21 days gestation) with intracerebroventricular (i.c.v.) administration of IL-1 beta. NKCA was reduced and blood beta-endorphin (beta EP) was increased with the progress of pregnancy. I.c.v. administration of IL-1 beta reduced NKCA and corticotropin-releasing hormone (CRH) in the median eminence (ME), and increased beta EP in virgin rats, but did not change any parameters in pregnant rats with 21 days gestation. These data suggest that the immunosuppressive effect of central administration of IL-1 beta is blocked by pregnancy. CRH in the ME and opioid system seem to be involved in the inhibitory effect of pregnancy on IL-1 beta-induced immunosuppression.

Animals↗

PubMed1998

The matrix gene expression of subacute sclerosing panencephalitis (SSPE) virus (Osaka-1 strain): a comparison of two sibling viruses isolated from different lobes of an SSPE brain.

The Fr/V and Oc/V sibling viruses of the Osaka-1 strain of the subacute sclerosing panencephalitis (SSPE) virus were defective in cell-free virus production. By radioimmunoprecipitation assay, the matrix (M) protein was not detected in cells persistently infected with the Osaka-1 strain. This undetectable expression was consistent with the selective reduction of antibody response to the M protein in the patient from whom the Osaka-1 strain was isolated. The sequence of the M gene, however, predicted that the protein could be synthesized because the translational start and stop codons for the protein were not altered. Northern blot hybridization demonstrated the selective defect of the monocistronic mRNAs for the M protein and the phosphoprotein (P) together with the dominant presence of the P-M bicistronic mRNA. This absence of the M mRNA was further confirmed by primer extension analysis. Therefore, the undetectable expression of the M protein in the infected cells was proved to be caused by a transcriptional defect. The two sibling viruses, isolated from remote portions of an SSPE brain, were indistinguishable in their viral characters, including the M gene sequences, which indicates the possibility of clonal expansion of the strain in the brain.

Animals↗

PubMed1998

Opioid peptides mediate heat stress-induced immunosuppression during pregnancy.

To clarify the involvement of the opioid system in enhanced immunosuppression induced by heat stress during pregnancy, we examined the effects of heat exposure and intraperitoneal administration of opioid receptor antagonist naloxone on beta-endorphin (beta-EP) in blood, pituitary lobes, and placenta as well as splenic natural killer cell activity (NKCA) and placental steroids in pregnant rats at 15-16 days gestation. Two-way analysis of variance revealed significant increases in blood beta-EP induced by heat and naloxone and a significant interaction between heat and naloxone on blood beta-EP and progesterone (P). Whereas heat reduced NKCA, intraperitoneal administration of naloxone reversed it. Significant increases in blood and placental beta-EP induced by both heat and naloxone administration and a significant interaction on blood and placental beta-EP was observed. These results suggest that immunosuppression produced by heat stress during pregnancy is mediated by the opioid system. A positive correlation between beta-EP in blood and placenta during heat and naloxone administration suggests that increased placental beta-EP during heat results in hypersecretion of beta-EP into blood. P increased by heat during pregnancy may be involved in the immunosuppression.

Animals↗