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Biomedical subjects

M Tabata

Publications and source records attributed to M Tabata.

At least 181 records · Page 10Linked to original sources
PubMed1992

Separation and sensitive determination of i-urobilin and 1-stercobilin by high-performance liquid chromatography with fluorimetric detection.

i-Urobilin and 1-stercobilin were separated by high-performance liquid chromatography on a reversed-phase octadecylsilane-bonded column and detected fluorimetrically through formation of phosphor with zinc ions in the eluent. The separation and the intensity of the fluorescence response were affected by concentrations of zinc acetate and sodium borate buffer, pH and methanol content in the eluent. The optimal eluent used consisted of 0.1% zinc acetate in 75 mM boric acid buffer (pH 6.0)-methanol (25:75). The detection limit was 0.2 microgram/l for both i-urobilin and 1-stercobilin (signal-to-noise ratio 2), which makes the method 250-2500 times more sensitive than conventional methods.

Bile Pigments↗
PubMed1992

Specific nickel(II)-transfer process between the native sequence peptide representing the nickel(II)-transport site of human serum albumin and L-histidine.

The kinetics and mechanism for Ni(II)-transfer of the native sequence tripeptide, L-aspartyl-L-alanyl-L-histidine-N-methylamide (AAHNMA), representing the Ni(II)-transport site of human serum albumin (HSA) and L-histidine (L-His) was studied in forward and reverse reactions in the pH range 6.5 to 9.0 at I = 0.2 and 25 degrees C. For the Ni(II)-transfer from Ni(II)-(L-His)2 to native sequence peptide, the rate-determining step is the formation of a mixed-ligand complex of NiH-1AB by deprotonation of peptide nitrogen from NiAB where A and B denote the anionic forms of AAHNMA and L-His, respectively. For the Ni(II)-transfer from Ni(II)-peptide to L-His, the rate-determining step is a bond breaking between Ni(II) and peptide nitrogen to form NiH-1A by protonation to a peptide nitrogen of NiH-2A. The equilibrium constants for the metal-transfer reaction of MH-2A + 2HB in equilibrium MB2 + A (A = Ni(II), Cu(II] were 10(3.29) and 10(0.78) for Ni(II) and Cu(II), respectively. NiB2 is 324 times as stable as CuB2. Furthermore, the ratio of Ni(II)/Cu(II) in the rate constants for the reaction of MB2 with A was found to be 2.8 x 10(-4). Thus, despite the similarities of Cu(II) and Ni(II) in the metal-binding sites of HSA and in reaction mechanism, Ni(II)-(L-His)2 complex is so stable thermodynamically and kinetically, compared to the Cu(II)-(L-His)2 complex, that Ni(II) is hardly transferred from Ni(II)-(L-His)2 to native sequence peptide. These findings may support specificities in the Ni(II)-transfer, its organ distribution, and its excretion through urine in vivo.

Amino Acid Sequence↗
PubMed1992

Localization of the biosynthesis and accumulation of monoterpenoids in glandular trichomes of thyme.

Quantitative analyses of the essential oils in intact glandular trichomes isolated from thyme cotyledons by the use of an adhesive tape and a glass capillary tube showed that the content of thymol per cotyledon was approximately equal to the sum total of thymol in peltate glandular trichomes (PGTs) and capitate glandular trichomes (CGTs). The amounts of thymol and gamma-terpinene in PGTs increased with time until 9 days after germination, when these monoterpenes were exclusively found in PGTs. The radioactivity of [U- (14)C]-sucrose administered to cotyledonal segments was incorporated into gamma-terpinene and thymol most actively by the peripheral part abundant in PGTs, whereas the incorporation was markedly decreased by a partial removal of PGTs from cotyledons. The cell-free extract of isolated PGTs was capable of cyclizing [ (14)C]-geranyl pyrophosphate into gamma-terpinene, but this enzymatic reaction failed when PGTs were removed from cotyledons. These results indicate that the biosynthesis and accumulation of monoterpenes in thyme seedlings take place primarily in PGTs.

Journal Article↗
PubMed1992

Genetic Control of Peltate Glandular Trichome Formation in Perilla frutescens.

The inheritance of peltate glandular trichome (PGT) formation in PERILLA FRUTESCENS leaves was investigated by crossing a normal strain with a variant strain with sparse PGT formation. The F (1) and F (2) data suggested that the sparse trichome is a dominant character that is controlled by a major gene and a few modifying genes which specifically inhibit the development of trichomes of the peltate type. Tracer experiments using [ (14)C]-sucrose showed that the quantity of essential oil components synthesized in the leaf was positively correlated with the number of PGTs, suggesting that the PGT is the main site for the biosynthesis of essential oil.

Journal Article↗
PubMed1992

Developmental changes in gastric mucus gel thickness: responsiveness to 16,16-dimethyl prostaglandin E2 and mucosal protection in the rat.

The gastric mucosa of newborn rats is sensitive to the damaging effects of acid and ethanol. We measured gastric mucus gel thickness in newborn, suckling, and weaned rats by inversion microscopic observation. The thickness in newborn rats was 52.2 +/- 6.7 microns and increased with age, reaching 96.8 +/- 5.6 microns in 8-wk-old rats (p less than 0.001). Oral administration of 16,16-dimethyl prostaglandin E2 at concentrations of 10 and 100 micrograms/kg body weight increased mucus thickness in 8-wk-old rats but had no effect in 1-wk-old rats. We also assessed the effect of 16,16-dimethyl prostaglandin E2 on the prevention of gastric mucosal damage induced by ethanol. Oral 16,16-dimethyl prostaglandin E2 reduced damage in 8-wk-old rats, but there was no effect in 1-wk-old rats. These data suggest that the susceptibility of newborn rats to gastric mucosal injury may be related to the relative thinness of the gastric mucus gel layer and the failure of prostaglandins to increase the mucus gel layer thickness.

16,16-Dimethylprostaglandin E2↗
PubMed1992

[Study of an outbreak of itai-itai disease].

We studied an outbreak of itai-itai disease in the Jinzu River basin, in Toyama, Japan. One hundred and fifty females recognized as itai-itai disease patients till by 1990 were studied for the ages and years of onset and residence in the cadmium-polluted area. 1. Cases were recognized from as early as 1929, increased gradually to the peak of 1955-1959 and rapidly decreased up to the 1970s. 2. It was found that the later the patients was born, the younger the age of onset, though there was no difference of ages of onset between the cases born in the 1910s and the cases born from 1920. 3. The onset of itai-itai disease was most frequently seen at 50-59 years of residence in the cadmium-polluted area. It was found that the later a person started to inhabit the cadmium-polluted area, the shorter the period of residence in the cadmium-polluted area up to onset of itai-itai disease. 4. Comparing the patients who inhabited the cadmium-polluted area from birth and those who had moved there from non-polluted areas, the age of onset was higher in the latter, but there were no significant differences in the period of residence up to onset. From these findings, it appeared that itai-itai disease was not caused by aging, but by cadmium exposure starting from the 1910s.

Cadmium Poisoning↗
PubMed1992

[[Comparison of mortality rates of elderly people in China and Japan]].

"The mortality rates and causes of death among elderly people aged sixty five and over were compared between China and Japan. The data used for comparison was China's 1990 and Japan's 1990 vital statistics. It appears that the mortality rate in China was higher than Japan. Comparing the causes of death, it was found that the death rates involving cerebrovascular diseases, malignant neoplasms and heart diseases in urban districts of China [were] higher than those in Japan. Also the death rate of people with bronchitis in rural districts was significantly higher in China.... The differences in the medical systems and life styles in China and Japan were suspected as the reasons for the differences of death rates and causes of death...." (SUMMARY IN ENG)

Adult↗
PubMed1992

An adriamycin-resistant subline is more sensitive than the parent human small cell lung cancer cell line to lonidamine.

Lonidamine, a unique new type of anticancer agent, has been shown to exert marginal activity in patients with resistant small cell lung cancer. We have assessed cytotoxic activity using seven human small cell lung cancer cell lines and the drug resistant small cell lung cancer sublines, Adriamycin-resistant SBC-3/ADM100, etoposide-resistant SBC-3/ETP and cisplatin-resistant SBC-3/CDDP. Although lonidamine had only a minimal activity in seven human small cell lung cancer cell lines, SBC-3/ADM100 cells were more sensitive to lonidamine than the parent SBC-3 cells to a 1.6-fold extent in terms of IC50. SBC-3/CDDP and SBC-3/ETP had no cross-resistance to lonidamine at all. These observations may be of potential clinical significance in treating small cell lung cancer.

Antineoplastic Agents↗
PubMed1992

[Immunohistochemical detection of carcinoembryonic antigen and P-glycoprotein in small cell lung cancer at diagnosis and relapse, with special reference to the tissue expression of CEA and response to chemotherapy].

Small cell lung cancer (SCLC) is one of the most sensitive tumors to drug therapy; however, the majority of patients eventually relapse within a few years. Emergence of drug resistance is thought to play a major role in the dismal course of this disease. However, the mechanism of drug resistance in SCLC still remains obscure. Based on the clinical observation that a significant proportion of patients with relapsing tumor show an elevated serum carcinoembryonic antigen (CEA) concentration while serum neuron-specific enolase (NSE) concentration remains normal, we attempted to determine whether the tissue of CEA is indicative of a clonal change in SCLC, in contrast with the tissue expression of NSE and P-glycoprotein (P-gp). We examined 22 SCLC patients with tumor specimens available both at diagnosis and at relapse. Of the 22 patients, two had CEA expression at diagnosis, and a further three patients showed CEA expression at relapse. It is of note that there were two patients whose tumors expressed NSE alone at diagnosis but expressed CEA alone at relapse. Serum CEA concentration was concordant with the tissue expression of CEA; however, serum NSE concentration was not concordant with the tissue expression of NSE. Tumors with CEA expression at relapse were generally resistant to salvage chemotherapy, while there was no close relationship between the tissue expression of P-gp and refractoriness to drugs at relapse. These findings indicate that the tissue expression of CEA in SCLC is a marker of a clonal change during chemotherapy, and such a clonal change would play a role in the emergence of drug resistance in SCLC.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1992

[A case of locally advanced esophageal cancer effectively treated with concurrent chemotherapy and radiotherapy].

A case of a 69-year-old man with locally advanced esophageal cancer was reported. The patient received five courses of chemotherapy consisting of cisplatin (30 mg i.v. days 1-5), 5-fluorouracil (500 mg i.v. days 1-5) and bleomycin (5 mg i.m. days 1-5) every four weeks with a split course irradiation at a dose of 50 Gy, which was concurrently given at the second, third and fourth course of the chemotherapy. Treatment was effectively carried out without severe toxicities. The patient achieved a histologically-confirmed complete remission after completion of the treatment. The patient is disease-free and fully active 28 months after the beginning of chemotherapy. The treatment modality appears to be useful for advanced esophageal cancer.

Aged↗
PubMed1992

[Lung injury associated with bucillamine therapy].

We have reported previously a first case of interstitial pneumonitis in rheumatoid arthritis treated with bucillamine in 1989. Thereafter, a dozen cases with lung injury associated with bucillamine therapy have been reported. To explore the similarities among these patients, we tried to carry out a survey concerning the lung injuries in these cases in the present study. We obtained the following results. (1) Patients with lung injury consisted of 7 females and 3 males, aged 65 years on average (59-72). (2) The total amount of bucillamine used was 20-40 g on average (5.1-144 g) during approximately 100 days. (3) Serum rheumatoid factor was positive in 9 of 10 cases. (4) HLA-DR4 was significantly (p less than 0.01) detected in all cases of lung injury associated with bucillamine. (5) Interestingly the effect of bucillamine on rheumatoid disease activity was excellent in most cases. (6) Drug lymphocyte stimulation test (DLST) using bucillamine was performed in 6 cases. Positive DLST was found in 3 of 6 cases. These results suggest that cell-mediated hypersensitivity reaction (Coombs & Gell type IV) may contribute to the development of lung injury associated with bucillamine therapy.

Aged↗
PubMed1991

Determinations of lactate and lactate dehydrogenase activity in serum with the flow injection analysis system involving immobilized enzyme column and chemiluminescence.

The methods for the highly sensitive flow injection analysis of lactate and lactate dehydrogenase (LDH) activity in serum using immobilized enzymes in column form and chemiluminescence detection which does not require a blank correction are described. The methods were based on the determination of chemiluminescence formed by the reaction of a luminol-ferricyanide mixture with hydrogen peroxide. This hydrogen peroxide was produced by the lactate oxidase (LOD) reaction from lactate, which was in serum or was produced by the action of LDH in serum. The action of LDH in a flow injection analysis system was performed for 2 min in an incubation coil placed parallel to the substrate-buffer line between the LOD column and the LOD/catalase column. Endogenous lactate in serum was removed by an immobilized LOD/catalase column prior to the action of LDH. The present method gave perfect linearity of the data up to 5.6 mmol/liter for lactate and 1840 IU/liter for LDH activity with satisfactory precision, reproducibility, and accurate reaction recoveries. The results from the lactate and LDH activity correlated satisfactorily with those obtained by other well-established methods.

Autoanalysis↗
PubMed1991

Anti-allergic effect of bryonolic acid from Luffa cylindrica cell suspension cultures.

The anti-allergic activity of bryonolic acid (1) isolated from the cultured cells of Luffa cylindrica L. (Cucurbitaceae) was compared with that of glycyrrhetinic acid (2), the aglycone of glycyrrhizin from licorice. Compound 1, when administered to rats intraperitoneally at a dose of 600 mg/kg, inhibited homologous passive cutaneous anaphylaxis more strongly than 2 at the same dose. Compound 1 also significantly inhibited delayed hypersensitivity in mice which could not be inhibited by 2. In contrast to 2, 1 showed not only little toxicity but no visible side effects on mice, without impairing the activity of the hepatic enzyme (4,5 beta-dihydrocortisone:NADP+ delta 4-oxidoreductase) involved in steroid catabolism.

Animals↗
PubMed1991

Transport and secretion of natural products in plant cell cultures.

Using the example of berberine in cell cultures of THALICTRUM and BERBERIS species, the transport and secretion of natural products in plant cell cultures is reviewed. Topics discussed are the subcellular localization of berberine biosynthesis, transport of berberine to vacuoles, extracellular release of berberine, mechanism of berberine secretion, uptake and transport of exogenous berberine, and the release of berberine by immobilized cells.

Journal Article↗