Studies on the association of NIDDM in Japanese patients with hyperthyroid Graves' disease.

We attempted to analyze the association of hyperthyroid Graves' disease with non-insulin-dependent diabetes mellitus (NIDDM). Forty-nine patients (23 males and 26 females; 7.6%) of a total of 647 patients with hyperthyroid Graves' disease had NIDDM, several years before or after Graves' disease was diagnosed. Only 1 patient had insulin-dependent diabetes mellitus. Compared with the general Japanese population (n = 9,133), the incidence of NIDDM (n = 348; 3.9%) in patients with Graves' disease was higher in all age groups. Only 4 patients (8.2%) of the 49 hyperthyroid patients with NIDDM had a history of being overweight (body mass index > 25). In contrast, 276 (79.9%) of the 348 diabetic patients were currently or previously overweight. Moreover, the incidence of a family history of diabetes (13 of the 49 hyperthyroid Graves' patients with NIDDM; 26.5%) was also lower in the patients with NIDDM in the general Japanese population (50% incidence). The male:female ration in patients with Graves' disease and NIDDM was 1:1.1; much different from that in the total Graves' disease population (1:4.1). Analysis of the HLA loci A, B, C, DR and DQ (35 determinations) in 35 hyperthyroid patients with NIDDM and in 386 subjects from the general population revealed a highly significant difference between them in the incidence of HLA-Cw4, -DR2, -DQw1, -DQw3 and -DQw4. This study suggests that there was an association of Graves' disease with NIDDM. A significant association of HLA-DR and -DQ loci was observed in hyperthyroid Graves' patients with NIDDM.     

Optimal seasonal timing of univoltine and bivoltine insects

This study examines the optimal seasonal timing of the life cycle for univoltine and bivoltine insects, assuming that resource availability has a peak in the middle of a year and is symmetric around it. Results show that if the growth rate increases in proporrion to the bodyweight, bivoltine life cannot be optimal. If the growth rate is a power function of the bodyweight with a power smaller than unity, a symmetric bivoltine solution can be the optimal provided that the resource availability has a plateau in the middle of the season. If the resource availability has a sharp peak, the optimal pattern is an asymmetric bivoltine solution in which the larval periods of two generations differ in length. The bivoltine life cycle is more likely to be superior to the univoltine one if: growth is fast, suitable growing season is long, biomass loss during nonlarval stages is small, and egg size is small.     

A new immobilization technique of whole cells and enzymes with colloidal silica and alginate

A mixed gel composed of colloidal silica and alginate (As gel) was prepared for the immobilization of enzymes or microorganisms. The physical strength of AS gel increased with the amount of colloidal silica. The ethanol production rate of Saccharomyces cerevisiae (IFO 0224) immobilized in AS gel was higher than in alginate gel (Al gel) in the early phase of growth. At a concentration of glucose of more than 10%, the ethanol production of immobilized yeast in AS gel was higher than in Al gel. Any difference was not recognized in the diffusion coefficient of glucose between AS and Al gels. The AS gel had an ability to retain proteins such as bovine serum albumin and gamma-globulin. The alkaline protease and beta-galactosidase in AS gel continued their function for a long time, but those immobilized in Al gel did not. Immobilized beta-galactosidase in AS gel had a higher thermal stability than in Al gel or free enzymes.     

Interaction of surfactants with bilayer of negatively charged lipid: effect on gel-to-liquid-crystalline phase transition of dilauroylphosphatidic acid vesicle membrane

The interaction of surfactants with the vesicle membrane of the negatively charged lipid, dilauroylphosphatidic acid, was investigated through their effect on the gel-to-liquid-crystalline phase transition of the lipid bilayer. Three types of surfactants (anionic, cationic and non-ionic) with different hydrocarbon chain length were examined. (i) Anionic sodium alkylsulfates affected the phase transition temperature, Tm, only weakly. (ii) Non-ionic alkanoyl-N-methylglucamides decreased Tm monotonously with increasing concentration. The depression of Tm induced by these surfactants was analyzed by applying the van't Hoff model for the freezing-point depression, and the partition coefficients of the surfactants between bulk water and lipid membrane were estimated. (iii) Cationic alkyltrimethylammonium bromides affected Tm in a complex manner depending on the hydrocarbon chain length of the surfactants. Octyl-/tetradecyl-trimethylammonium bromide depressed/elevated Tm monotonously with increasing concentration, whereas the change in Tm induced by decyl- and dodecyltrimethylammonium bromides was not monotonous but biphasic. This complex behavior of the phase transition temperature was well explained, based on the statistical mechanical theory presented by Suezaki et al. (Biochim. Biophys. Acta, 818 (1985) 31-37), which takes into account the interaction between surfactant molecules incorporated in the lipid membrane.     

delta 12-Prostaglandin J2, an ultimate metabolite of prostaglandin D2 exerting cell growth inhibition

L-1210 murine leukemia cells were exposed to prostaglandin D2 (PGD2), 10 micrograms/ml, in culture medium for various time, and subsequent cell growth was observed. More than 24 h exposure to PGD2 was required to inhibit cell growth almost completely. During this period, PGD2 degraded time-dependently into several products. The major product was identified as delta 12-PGJ2 by TLC, UV and mass spectra. When delta 12-PGJ2 was added to cells instead of PGD2, it evoked growth inhibition with much shorter contact time than PGD2. In addition, when the medium containing PGD2 was preincubated at 37 degrees C for 24 h, it elicited growth inhibition with only 6 h contact with cells. Furthermore, when the medium containing PGD2 was changed every 6 h during 24 h exposure time to cells, no significant growth inhibition was observed. These results suggested that PGD2 per se has little, if any, growth inhibitory activity, and delta 12-PGJ2 is an ultimate metabolite exerting growth inhibition. This action appears to be independent of cAMP, since delta 12-PGJ2 was virtually inactive in raising intracellular cAMP levels.     

Structural organization of the human kininogen gene and a model for its evolution

The entire human kininogen gene has been isolated as a set of overlapping genomic DNA fragments, and the 11 exons encompassing approximately 27 kilobase pairs have been mapped by restriction enzyme analysis and nucleotide sequence determination. The nine 5'-terminal exons encode the 5'-untranslated region and the protein-coding region for the signal peptide and the heavy chain, which are common for high molecular weight (HMW) and low molecular weight (LMW) prekininogen mRNAs. Exon 10 consists of the common sequence for bradykinin and the immediately following unique sequence for HMW prekininogen mRNA. Exon 11 is then located following a 90-nucleotide sequence downstream from exon 10 and precisely specifies the sequence unique to LMW prekininogen mRNA. This, together with the hybridization analysis of total human cellular DNA, leads us to conclude that human HMW and LMW prekininogen mRNAs are produced from a single gene as a consequence of alternative RNA processing events. The structural analysis of the kininogen gene also shows that each of the nine 5'-terminal exons discretely specifies the nine protein domains observed in the amino-terminal portion of the kininogens. Furthermore, these nine genetic domains can be characterized by a thrice repeated pattern of three genetic segments, and two sets of these three domains, encompassing exons 3-5 and exons 6-8, are most closely related to each other. Therefore, we have proposed two successive duplication mechanisms as a model for the generation of the structure of the kininogen gene.     

Methyl cinnamate derivatives enhance UV-induced mutagenesis due to the inhibition of DNA excision repair in Escherichia coli B/r

UV-induced mutagenesis in Escherichia coli B/r WP2 was enhanced by certain derivatives of methyl cinnamate which themselves were not mutagenic. Methyl ferulate, methyl isoferulate and methyl sinapate showed this effect markedly. Such an enhancement effect was absent with the derivatives of cinnamic acid and ethyl cinnamate and was not observed in Escherichia coli WP2s uvrA. Methyl sinapate also enhanced 4NQO-induced mutation and suppressed liquid-holding recovery in the above repair-proficient strain. The presence of methyl sinapate in plating agar medium decreased the survival of UV-irradiated cells of a recombination-repair-deficient strain, CM571 recA. However, the effect was not observed with those of WP2s uvrA. In an in vitro experiment in which the removal rate of thymine dimers was measured, methyl sinapate clearly inhibited this repair event. From these results, we conclude that methyl sinapate inhibits DNA excision repair, thus enhancing UV mutagenicity.     

Purification and characterization of thermostable leucine dehydrogenase from Bacillus stearothermophilus

Leucine dehydrogenase (l-leucine: NAD⁺ oxidoreductase, deaminating, EC 1.4.1.9) has been purified to homogeneity from a moderate thermophilic bacterium, Bacillus stearothermophilus. Am improved method of preparative slab gel electrophoresis was used effectively to purify it. The enzyme has a molecular mass of about 300,000 and consists of six subunits with identical molecular mass (Mr, 49,000). The enzyme does not lose its activity by heat treatment at 70° C for 20 min, and incubation in the pH range of 5.5–10.0 at 55° C for 5 min. It is stable in 10 mM phosphate buffer (pH 7.2) containing 0.01% 2-mercaptoethanol at over 1 month, and is resistant to detergent and ethanol treatment. The enzyme catalyzes the oxidative deamination of branched-chain l-amino acids and the reductive amination of their keto analogs in the presence of NAD⁺ and NADH, respectively, as the coenzymes. The pH optima are 11 for the deamination of l-leucine, and 9.7 and 8.8 for the amination of -ketoisocaproate and -ketoisovalerate, respectively. The Michaelis constants were determined: 4.4 mM for l-leucine, 3.3 mM for l-valine, 1.4 mM for l-isoleucine and 0.49 mM for NAD⁺ in the oxidative deamination. The B. stearothermophilus enzyme shows similar catalytic properties, but higher activities than that from Bacillus sphaericus.Dedicated to Prof. Dr. G. Drews on the occasion of his 60th birthday     

Receptive field mechanisms of ganglion cells in the cat retina

On the basis of anatomical and physiological results of the vertebrate retina, a method is proposed for analysing the respective fields of ganglion cells in the cat retina. In the model, we assume the following: (a) Ganglion cells receive their input from bipolar and/or amacrine cells. (b) The nonlinearity of ganglion cell responses is due to the activities of transient type amacrine cells. The method has been proved to be effective. According to the results of this investigation, the receptive field properties of X type and Y type ganglion cells are heterogeneous. Thus, it may be considered that their receptive fields consist of center and surround mechanisms. The receptive field properties of X-cells are almost linear and the X-cells seem to receive most of their input from bipolar cells. On the other hand, the ones of Y-cells are highly nonlinear. Consequently, it is conceivable that the Y-cells receive their input mainly from transient type amacrine cells.     

False positive reaction for carcinoembryonic antigen in paget cells

Virchows Archiv B Cell Pathology - Paget cells from cases of mammary and extramammary Paget’s disease were examined for carcinoembryonic antigen (CEA) and CEA-related antigens by the...