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Biomedical subjects

T Nagata

Publications and source records attributed to T Nagata.

At least 505 records · Page 28Linked to original sources
PubMed1988

Effects of zinc and EDTA on tissue cadmium in various smooth muscles in rabbit and guinea-pig.

1. The effects of zinc (Zn2+) and ethylenediaminetetra-acetic acid (EDTA) on tissue cadmium (Cd2+) were investigated in the smooth muscles of rabbit trachea, taenia coli, aorta and guinea-pig taenia coli. 2. After an Cd uptake in high-K2+ solution, samples were rinsed with cold high-K2+, cold Zn2+ or cold EDTA solution without Cd2+ and the results were quantitatively different from each other. 3. Concentration-response curves were obtained with each treatment of cold solution. 4. It is suggested that tissue Cd2+ can be divided into 3 fractions in the surface membrane and there is another fraction in cellular space.

Animals↗
PubMed1988

Toxicological analysis of thiamylal in biological materials by gas chromatography/mass spectrometry.

A reliable and sensitive method to analyze thiamylal in biological materials was developed, using gas chromatography/mass spectrometry (GC/MS). A quantitative determination was made by use of mass fragmentography with the lower detection limit of 0.01 microgram/g. Thiopental was used as the internal standard. Distribution of the drug in the blood and body tissues of rats was examined. The method was then used to detect thiamylal in tissues from an autopsied patient and concentration of this drug in the body materials was evaluated, from medico-legal aspects.

Adipose Tissue↗
PubMed1988

N-methylation: potential mechanism for metabolic activation of carcinogenic primary arylamines.

Two amine N-methyltransferases isolated from rabbit liver catalyze S-adenosylmethionine-dependent N-methylation of benzidine and 4-aminobiphenyl but not of 4-aminoazobenzene or 2-aminobiphenyl. The enzymatic reaction products were analyzed and found to be identical to synthetic N-methylbenzidine and N-methyl-4-aminobiphenyl. N-Methylation may be a critical step in the metabolic activation of primary arylamines because N-methylarylamines, unlike primary arylamines, are readily N-oxygenated by the NADPH- and oxygen-dependent microsomal flavin-containing monooxygenase. Kinetic studies carried out with the purified porcine liver monooxygenase demonstrate that, while activity with primary arylamines could not be detected, N-methyl derivatives of benzidine, 4-aminoazobenzene, and 4-aminobiphenyl are substrates. Products formed from N-methyl-4-aminobiphenyl had the properties of the hydroxylamine and/or nitrone in that the enzyme- and time-dependent incubation product(s) reduced Fe3+ to Fe2+, and formaldehyde was formed during the course of the reaction. These data suggest that N-methyl-4-aminobiphenyl is oxidized to N-hydroxy-N-methyl-4-aminobiphenyl, which can undergo further oxidation to a nitrone that hydrolyzes to formaldehyde and N-hydroxy-4-aminobiphenyl.

Aniline Compounds↗
PubMed1988

Gonadotropin response to LH-RH in anorexia nervosa and bulimia.

Serum LH and FSH levels before and after stimulation with LH-RH were measured in 9 patients with bulimia, 7 with a restricting subtype and 6 with a bulimic subtype of anorexia nervosa. All patients with anorexia nervosa and 5 (56%) patients with bulimia showed amenorrhea for at least 5 months, while 4 (44%) of the bulimic patients showed oligomenorrhea. Mean basal levels of LH and FSH were low in patients with restricting and bulimic anorexia nervosa, but were normal in patients with bulimia. The response of LH and FSH to LH-RH was impaired in approximately half of the patients with the two subtypes of anorexia nervosa, whereas it was normal in all but one patient with bulimia. These results suggest that bulimic patients with amenorrhea or oligomenorrhea have hypothalamic dysfunctions, which do not appear to be due solely to low weight or to metabolic changes resulting from binge eating, vomiting or purgative use.

Adolescent↗
PubMed1988

Relationship between forced expiratory flow and tracheal sounds. Possible effect of vortices on flow.

We measured both tracheal sounds and forced expiratory flows simultaneously in 20 normal subjects and 4 patients with stenosis of the main bronchus. Spectral analysis of the tracheal sounds revealed development of discrete line spectra, the frequencies of which ranged between 488 and 942 Hz. There was a positive correlation between these frequencies and the peak flows (r = 0.601). We speculate that the origin of these line spectra are vortices rather than the vibrations of the wall. It is postulated that the pressure drops caused by vortices make the airways more susceptible to collapse and may lead to flow limitation.

Adult↗
PubMed1988

Gasoline and kerosene components in blood--a forensic analysis.

A reliable method to analyse small amounts of fuel components in biological materials, using two simultaneous procedures, head space and solvent extraction methods has been developed. Gas chromatography/mass spectrometry (GC/MS) was used for qualitative and quantitative determinations. The aliphatic hydrocarbons with carbon numbers of 5 to 8 and aromatics such as benzene, toluene and xylenes were detected in laboratory animals, following exposure to gasoline vapour, using the head space method. Aliphatic hydrocarbons with carbon numbers over 9 as well as the aromatics with carbon number 9 group including cumene, mesitylene, pseudocumene and 1,2,3-trimethylbenzene were determined by the solvent extraction method following exposure to kerosene vapour. The lower limits of detection were 0.01 micrograms and 50 pg in gasoline and kerosene components, respectively. The methods were found to be applicable in confirming the cause of human deaths.

Adult↗
PubMed1988

Detection of H-2K mRNA in mouse 8-cell embryo by cDNA cloning.

Mouse MHC class I gene expression in 8-cell embryo was examined by cDNA cloning. We constructed a cDNA library from 8-cell embryos of ICR mice and isolated a class I cDNA from 3.0 x 10(5) phage clones of the library. Sequencing analysis of this clone revealed it to include the cDNA fragment extending from the exon 6 of the cytoplasmic portion to 3' untranslated region 1 of H-2K gene. Qa, Tla or other embryonic class I cDNA have not been isolated in the library.

Animals↗
PubMed1988

Immunohistochemical studies on the localization of fibronectin in human thyroid neoplastic tissues.

Fibronectin (FN) has been considered to be involved in the malignant transformation of cells. It was thus of interest to morphologically study the cell surface distribution of FN in various types of thyroid neoplasms employing immunohistochemical techniques. Immunohistochemical staining using the specific anti-human FN antibody was performed by the avidin-biotin-peroxidase complex procedure. Compared to the staining pattern of normal thyroid tissues (control), differences in staining in malignant thyroid lesions and even in fetal and embryonal adenomas were evident, often on the lateral and basal aspects of the cell membrane. Colloid adenomas, however, showed FN staining on the basement membrane, basically similar to the controls. Moreover, in thyroid carcinoma, different staining patterns relating to each of the histological types were observed. The present investigation demonstrates the heterogeneity of the thyroid neoplasms in terms of FN binding.

Adenocarcinoma↗
PubMed1988

[Pulmonary tuberculosis in patients with oral cancer].

During an 11 year period, from 1976 to 1986, 33 (10.1%) out of 328 patients with oral cancer treated at our clinic had either a scarred pulmonary tuberculosis (TB) or active TB. Four of these 33 patients developed active TB. In two of these cases TB occurred before the therapy of oral cancer commenced and in the other two, after the operation for oral cancer. In one of the 4 cases, a recrudescence of the TB was suspected. Five cases that were suspected of having TB on analysis of their chest X-rays were administered prophylactic anti-tuberculous chemotherapy, after which no recrudescence or onset of TB.

Adult↗
PubMed1988

Immunohistochemical studies on local antitumor effects of streptococcal immunopotentiator, OK-432, in human solid malignant tumors.

Immunocytochemical techniques were used to clarify the local inhibitory effects of a streptococcal immunopotentiator, OK-432, against solid malignant tumor growth. Natural killer (NK) cells and fibronectin were chosen as immunostaining markers to demonstrate the antitumor effects. Immunocytochemical staining was performed by the avidin-biotin-peroxidase complex method. These investigations demonstrated that (1) local administration of OK-432 seems to promote a marked induction of NK cells and fibroblasts around or entering into the cancerous lesions and (2) the cancer cell-killing effect of NK cells and the fibronectin-enriched stromal reaction augmented by the injection of OK-432 suggest at least the possibility of protection against neoplastic growth with invasion and the spread of distant or nodal metastases of solid carcinomas.

Adenocarcinoma↗
PubMed1988

Extractive alkylation and gas chromatographic analysis of sulfide.

A sensitive analysis of sulfide in blood was established, using an extractive alkylation technique. Pentafluorobenzyl bromide was used as the alkylating agent, tetradecyldimethylbenzylammonium chloride as the phase-transfer catalyst, and potassium dihydrogenphosphate as the buffer to suppress the formation of sulfide. Mass fragmentography was used to identify the sulfide derivative and gas chromatography with an electron capture detector was used for quantitative determination, with the lowest limit of detection being about 0.01 microgram/g. The blood level of rats exposed to hydrogen sulfide was also determined.

Alkylation↗
PubMed1987

Screening of volatile compounds present in human blood using retention indices in gas chromatography.

The retention index in gas chromatography was introduced to screen volatile compounds in blood. Sixty-one organic compounds with high volatility were determined using a gas chromatograph with a flame ionization detector and a packed column system with 10% OV-17. Porapak P was used as a supplementary column for determining alcohol. Detection limits were determined for several substances. This method was used to analyse blood samples obtained at autopsy from patients suspected of solvent abuse. This approach proved to be superior to conventional gas chromatography in that mixed unknown volatiles in the blood could be identified simply and rapidly.

Adult↗
PubMed1987

Nucleotide sequences required for a ColE1-type plasmid to replicate in Escherichia coli cells with or without RNase H.

To elucidate the replication mechanism of a ColE1-type plasmid in RNase H-deficient (rnh-) strains of Escherichia coli, we constructed plasmid derivatives that deleted the whole, or a part, of the 5'-AAAAA-3' sequence (positions -3 to +2) that acts as the origin of replication in vivo and in vitro in the presence of RNase H. The activity of plasmid replication in rnh+ cells was found to be reduced by alterations of the AAAAA sequence. The activity could be restored when the derivatives, retaining the upstream sequence down to -8, regained a sequence containing at least two A residues in the region from -3 to +2. By contrast, replication in rnh- cells was maintained at high levels even when the deletion included the AAAAA sequence and extended up to position -7. The activity in rnh- cells decreased as deletions proceeded to -8 and further up to -17, and was abolished completely by further upward deletions. We concluded that in rnh- cells the plasmid replicates by a mechanism that operates only when RNase H is inactive. This RNase H-sensitive replication in rnh- cells seems to require the RNA-DNA hybrid formation that is also required for RNase H-dependent replication in rnh+ cells. The hybrid formation probably contributes by unwinding a portion of DNA from which replication can be initiated.

Base Sequence↗