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Biomedical subjects

N Watanabe

Publications and source records attributed to N Watanabe.

At least 1,135 records · Page 63Linked to original sources
PubMed1984

Amperometric detection of muramic acid in high-performance liquid chromatography with a post-column reaction.

Highly sensitive detection of muramic acid has been developed by using an amperiometric detector in high-performance liquid chromatography. The reducing ability of muramic acid was coupled with the redox reaction of bis(1,10-phenanthroline)copper(II), CBP, as mediator. CBP, reduced by muramic acid in a post-column reaction, was reoxidized with the amperometric detector, resulting in a highly sensitive and selective detection. A doublet peak was obtained, due to the alpha- and beta-anomers of muramic acid. This was merged into a single peak by adding phosphoric acid to the sample solution. Addition of phosphoric acid to serum, spiked with muramic acid, also clarified the chromatogram. The detection limit was 0.05 ppm (4 pmol of muramic acid injected) in serum samples.

Carbohydrate Metabolism↗
PubMed1984

Receptor-binding kinetics of A-14 and A-19 125I-labelled insulin.

Receptor-binding kinetics and degradation of tyrosine A-14 and A-19 125I-labelled insulin was studied using cultured human lymphocytes. Receptor-binding ability of A-14 insulin was 1.5-times as high as that of A-19 insulin. Dissociation from receptors on lymphocytes showed no difference between these two labelled insulins. In association studies percent bound of A-14 insulin was 1.5-times as high as that of A-19 insulin at any time after incubation. These results suggested that lower binding affinity of A-19 insulin was due to decreased association rate, but not due to increased dissociation rate. Degradation of A-14 insulin by incubation media of lymphocytes was also 1.5-times as high as that of A-19 insulin.

Humans↗
PubMed1984

Determination of trace amounts of siloxanes in water, sediments and fish tissues by inductively coupled plasma emission spectrometry.

A simple and rapid method is described for the separation and determination of organosilicones in water, sediment and samples of fish tissues, using inductively coupled plasma emission spectrometry. Organosilicone extract with petroleum ether is evaporated to dryness. The damp residue is dissolved in methyl isobutyl ketone, aspirated into the plasma. Optimisation of gas (plasma support, coolant and carrier) flow-rates and plasma height are discussed. Detection limit (2 delta) is 0.01 microgram ml-1 for organosilicone and is adequate for environmental samples. Precision of the proposed method is 4.7% for river water, 10.8% for river sediment, 1.2% for sewage sludge and 13.3% for fish tissue.

Animals↗
PubMed1984

Receptor binding and biological activity of [SerB24]-insulin, an abnormal mutant insulin.

[SerB24]-insulin, the second structurally abnormal mutant insulin, and [SerB25]-insulin were semisynthesized and were studied for receptor binding and biological activity. Receptor binding and biological activity determined by its ability to increase 2-deoxy-glucose uptake in rat adipocytes were 0.7-3% of native insulin for [SerB24]-insulin and 3-8% for [SerB25]-insulin. Negative cooperative effect of these analogues was also markedly decreased. Immunoreactivity of [SerB24]-insulin was decreased whereas that of [SerB25]-insulin was normal. Markedly decreased receptor binding of [SerB24]-insulin appeared to be due to substitution of hydrophobic amino acid, Phe, with a polar amino acid, Ser, at B24.

Adipose Tissue↗
PubMed1984

Relation of the extra-sequence of the precursor form of chicken liver delta-aminolevulinate synthase to its quaternary structure and catalytic properties.

Precursor and mature forms of delta-aminolevulinate (ALA) synthase were purified to near homogeneity from chicken liver mitochondria and cytosol, respectively, and their properties were compared. The enzyme purified from mitochondria had apparently the same subunit molecular weight (65,000) as that of the native mitochondrial enzyme. The enzyme purified from the cytosol fraction, however, showed a subunit molecular weight of about 71,000 which was somewhat smaller than that estimated for the native cytosolic enzyme (73,000). The enzyme purified from liver cytosol seems to have been partially degraded by some endogenous protease during the purification, but may have the major part of the signal sequence. On sucrose density gradient centrifugation, the purified mitochondrial and cytosolic ALA synthases showed an apparent molecular weight of about 140,000, indicating that both enzymes exist in a dimeric form. The ALA synthase synthesized in vitro was also shown to exist as a dimer. Apparently the extra-sequence does not interfere with the formation of dimeric form of the enzyme. The purified cytosolic ALA synthase had a specific activity comparable to that of the purified mitochondrial enzyme. Kinetic properties of the two enzymes, such as the pH optimum and the apparent Km values for glycine and succinyl-CoA, were quite similar. The extra-sequence does not appear to affect the catalytic properties of ALA synthase. The isoelectric point of the cytosolic ALA synthase was 7.5, whereas that of the mitochondrial enzyme was 7.1. This suggests that the extra-sequence in the cytosolic enzyme may be relatively rich in basic amino acids.

5-Aminolevulinate Synthetase↗
PubMed1984

Bioconcentration potential of polydimethylsiloxane (PDMS) fluids by fish.

The water solubilities (S), octanol/water partition coefficients (KOW) and bioconcentration factors (BCF) of four polydimethylsiloxane (PDMS) fluids covering a wide range of molecular weight were measured. It is shown that a previously described correlation between S and KOW for organic chemicals may be invalid for PDMS fluids; an alternative correlation is proposed. Some PDMS fluids tend to have a bioconcentration potential in silver carp.

Animals↗
PubMed1984

A therapeutic trial of caerulein to a long-term heavy marihuana user with amotivational syndrome.

A male marihuana user with amotivational syndrome who responded poorly to neuroleptic therapy was treated four times with weekly intramuscular injection of caerulein in a dose of 0.6 micrograms/kg. He was maintained on his previous neuroleptic medication during the study period. The BPRS was used to rate the patient's symptoms. There were remarkable improvements in the total scores and the psychosis subscale score, which consists of the following symptoms that do not respond well to neuroleptic therapy in chronic schizophrenia: emotional withdrawal, mannerisms and posturing, uncooperativeness, and blunted affect. These improvements persisted for two weeks after cessation of caerulein administration, after which the patient's condition gradually worsened. Nevertheless, the improvement recurred upon reinjection of caerulein. These findings indicate that the improvement observed seems to be due to caerulein, and suggest that caerulein may be a useful and effective therapeutic drug for marihuana user with amotivational syndrome.

Adult↗
PubMed1984

In vitro effects of glucocorticoid on glucose transport in rat adipocytes: evidence of a post-receptor coupling defect in insulin action.

The in vitro effect of glucocorticoid on insulin binding and glucose transport was studied with rat adipocytes. Isolated rat adipocytes were incubated with or without 0.70 microgram/ml (1.9 mumol) of hydrocortisone in TCM 199 medium at 37 degrees C, 5% CO2/95% air (v/v), pH 7.4, for 2, 4, and 8 h, and then fat cell insulin binding and insulin-stimulated 3-O-methylglucose transport were measured. Hydrocortisone did not affect insulin binding in terms of affinity or receptor number. Glucose transport in the absence of insulin was significantly decreased at the incubation time of 2 h and continued to decrease up to 8 h of incubation with hydrocortisone. Decreased insulin sensitivity of glucose transport (i.e., a right-ward shift of the dose response curve) was also demonstrated after 2 h incubation with hydrocortisone, and the ED50 of insulin was maximally increased at 4 h of incubation (0.53 ng/ml for treated vs. 0.22 ng/ml for control cells). Maximal insulin responsiveness was also significantly decreased in treated cells after 8 h incubation with hydrocortisone. When percent maximum glucose transport was expressed relative to receptor-bound insulin, the ED50 values of treated and control cells were 10.5 and 7.2 pg of bound insulin, per 2 X 10(5) cells, respectively. Thus, it was evident that glucocorticoid induced a post-receptor coupling defect in the signal transmission of insulin-receptor complex.

3-O-Methylglucose↗
PubMed1984

Adjuvant effects of aluminum silicate on IgE and IgG1 antibody production in mice.

The adjuvant effects of aluminum silicate on IgE and IgG1 antibody production were investigated. BALB/c mice were immunized intraperitoneally with 10 micrograms ovalbumin (OA) adsorbed on 0.2, 2, or 20 mg aluminum silicate. The enhancement of anti-OA IgE antibody production was observed in the mice injected with aluminum silicate and antigen compared with the mice injected with antigen alone. Anti-OA IgE antibody production with 2 and 20 mg aluminum silicate was greater than that with aluminum hydroxide (alum) as an adjuvant. Similar adjuvant effects with 2 mg aluminum silicate or alum were observed in AKR and C57BL/6 mice using 10 micrograms OA, and in BALB/c mice using 2 micrograms DNP-KLH (dinitrophenyl keyhole limpet hemocyanin): IgE antibody production induced by aluminum silicate adjuvant persisted for weeks in these experiments. The enhancement of IgG1 antibody production to OA mixed with aluminum silicate was also demonstrated. However, no difference between aluminum silicate and alum was observed on the IgG1 antibody production.

Adjuvants, Immunologic↗
PubMed1984

Receptor-mediated degradation by rat adipocytes: comparison of A-14 with A-19 125I-labelled insulin.

We compared A-14 and A-19 125I-labelled insulin in receptor-binding and degradation. Percent receptor-binding of A-14 and A-19 125I-labelled insulin to 2.4 X 10(9)/ml erythrocytes after 210 min incubation at 15 degrees C was 7.8 and 4.9%, respectively. Percent insulin-receptor binding of A-14 insulin was 1.6 times greater than that of A-19 insulin. A similar result was obtained in an adipocytes insulin binding study. Percent receptor-binding of A-14 and A-19 insulin to 2 X 10(5)/ml fat cells after 30 min incubation in the above buffer was 3.9 and 2.4%, respectively. Degradation of A-14 and A-19 insulin in rat adipocytes was also studied by molecular sieve column chromatography. Isolated rat adipocytes were allowed to associate with A-14 and A-19 125I-insulin for 60 min at 37 degrees C, pH 8.0 in a HEPES-phosphate buffer, and then cells were separated from the buffer by centrifugation. After solubilization with triton X-100, both the solubilized cells and the incubation medium were applied to the Bio-Gel P-30 column to assess the insulin degradation. Degradation of A-14 125I-insulin by the isolated rat adipocytes was 1.6 times greater than that of A-19 125I-insulin. Furthermore, the peak which was thought to be intermediate degradation products of insulin was obtained between the peak of intact insulin and that of 125I-tyrosine. Such a peak of intermediates was much smaller in the incubation media than in the cell-associated materials.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗