Metallothionein induction in rat liver by dietary restriction or exercise and reduction of exercise-induced hepatic lipid peroxidation.

Metallothioneins (MTs) occur throughout the animal kingdom and they are induced in vivo by metals, hormones, cytotoxic agents, and some kind of stress. It is well known that various stresses such as starvation and immobilization can induce MT synthesis in animal tissues, but the influence of dietary restriction is unknown. The MT levels in the liver increased by food-deprivation and then decreased by refeeding, and a long period of starvation down-alters hepatic MT levels. When the stress is intensified, the induced quantity of hepatic MT is reduced. It became clear that hepatic MT concentrations are controlled within a two fold limit when stressed by dietary restriction. MT was also induced in rat liver at recovery stage following an exhaustive running exercise, and thionein was synthesized first and then zinc bound to the protein. The half-life of hepatic MT induced by exercise (which is a nonmetallic inducer) was estimated at 5.2 h. Preinduced MT markedly suppressed exercise-induced lipid peroxidation in rat liver.

Anomaly in atmospheric radon concentration: a possible precursor of the 1995 Kobe, Japan, earthquake.

Clear seismic-related anomalies in the radon (222Rn) concentration of the atmosphere were observed prior to the Kobe earthquake (magnitude 7.2) on 17 January 1995. The radon anomalies were observed at a monitoring station in Kobe, which is located about 20 km away from the epicenter. The means of radon concentration in the atmosphere for each day were calculated using the data observed between April 1984 and March 1994, in order to obtain the normal radon variation. The difference between the smoothed radon concentration and the smoothed mean radon concentration is the residual value. Using the weekly averages of residual values in the historical period, the weekly residual value in the validation period were predicted. The historical period was from April 1984 to March 1994. The validation period was from April 1994 to January 1996. The seismic-related radon anomaly higher than the 99% confidence limit of the residual value of radon concentration in the atmosphere was observed beginning about 2 mo before the earthquake.

Measurement of metallothionein in rat tissues by a chromatographic method using the fluorometry of thiol groups.

The estimation of metallothionein (MT) levels in a biological sample is required to study the physiological role or the induction of MT, which is a multifunctional protein. MT contains 61 amino acids with 20 homologous cysteines. The high selectivity, sensitivity and stability of N-[4-(dimethylamino-2-benzofuranyl)phenyl]maleimide (DBPM) for the determination of SH groups was very useful for the determination of MT. The detection limit of MT by this method was 10 ng/0.5 ml. This method made it possible to measure MT levels in normal tissues in combination with gel filtration chromatography. The age-dependent change in MT levels in normal rat tissues was also investigated by the present method. MT levels in normal rat tissues vary with age. It is thought that this fact is correlated with the biological roles of MT.

Effect of preinduction of metallothionein on tissue distribution of silver and hepatic lipid peroxidation.

Silver ion causes a number of toxic effects, it decreases the activities of lactate dehydrogenase and glutathione peroxidase, and the peroxidation of membrane lipids. Silver ions complex strongly to sulfhydryl groups and the effects of preinduction of metallothionein, a sulfur-rich protein, on silver administration in rats were examined. The preinduction of metallothionein decreased the mortality of mice following silver administration. A major portion of the incorporated silver in the liver was bound to the basal membrane and cellular components, and the distribution of silver into cytosol was small. The preinduction of metallothionein decreased the amount of bound silver in the membrane and increased the distribution of silver in the cytosol; in addition, it depressed silver-induced lipid peroxidation in liver.

Inhibitory effects of hyaluronan on [14C]arachidonic acid release from labeled human synovial fibroblasts.

The effects of hyaluronan (HA) on the release of arachidonic acid (AA) from phospholipids induced by bradykinin in synovial fibroblasts of osteoarthritic patients were examined. HA inhibited [14C]AA release from prelabeled synovial cells stimulated with and without bradykinin 1 hr after incubation with HA and thereafter. The inhibitory effects of HA on [14C]AA release were dependent on the concentration and molecular weight of HA. However, inhibition of [14C]AA release by HA was not merely due to the viscosity of HA. The [14C]AA release induced by calcium-ionophore A23187 was also inhibited by HA with a high molecular weight. In addition, HA did not affect [14C]AA uptake by the cells. Our results suggest that HA with a high molecular weight elicits anti-inflammatory effects, at least in part, by inhibiting AA release in inflamed joints.

Determination and biokinetics of germanium in mouse tissues by atomic absorption spectrometry with electrothermal atomization.

There are few papers on the analysis of Ge in biomaterials. A highly sensitive method is required for such determination of Ge because its concentration is very low. We developed a sensitive analytical method for determining Ge in biomaterials by using 0.05 mol/l Co (NO3)2 media as a matrix modifier with flameless atomic absorption spectrometry. This method was applied to the determination of Ge in mouse tissues, and the biokinetic parameters of Ge in mouse tissues were evaluated using the data of uptake and retention after a single peroral administration of GeO2 solution. Ge was not detectable in the blood or tissues of normal mice. The uptake of Ge into kidney is much larger than that into other tissues after injection of GeO2 solution. The disappearance of Ge from blood and the tissues is very fast. It could hardly be detected in any of the tissues 24 h after injection. The biological half-life of Ge in brain is 6.3 h, but in other tissues--1.2 h (in blood) to 4.5 h (in pancreas)--it is shorter than in brain. By the fact that Ge is rapidly excreted from all tissues, it can be understood that Ge is not detected in normal mouse tissues and its toxicity is weaker than that of other metals.

[The study of polyamine levels and enzyme activities in metabolic pathway of polyamine in spleen of mice inoculated tumor cells].

Polyamine concentrations, ornithine decarboxylase (ODC) activity and S-adenosyl-L-methionine decarboxylase activity in the spleen of ICR mice after s.c. inoculation of 2 X 10(6) Sarcoma-180 ascites tumor cells were studied. ODC activity and putrescine concentration in spleen were markedly elevated at 1 and 5 d after inoculation of tumor cells, and spleen weight increased from 3 to 7 d after the inoculation. The elevations at 5 d after inoculation corresponded to the enlargement of spleen. By s.c. inoculation of 2 X 10(6) METH-A ascites tumor cells into BALB/c mice, ODC activity and putrescine concentration in the spleen were also elevated at about 1 d after inoculation. On the other hand, when normal cells (spleen cells) were inoculated into ICR mice, those variations were not observed. From these facts, it was thought that elevations of ODC activity and putrescine concentration in the spleen at 1 d after inoculation of tumor cells were related to the immune response. Further, those were elevated according to the number of inoculated cells, and when cell membranes of 2 X 10(6) Sarcoma-180 ascites tumor cells were inoculated, those were also elevated at about 1 d after the inoculation. From the above facts, it was proved that elevations of ODC activity and putrescine concentration in the spleen at 1 d after the inoculation of tumor cells were due to antigenicity of tumor cell membranes and those were dependent on the number of inoculated tumor cells.

Peptidyl carbamates incorporating amino acid isosteres as novel elastase inhibitors.

The design and synthesis of 13 novel peptidyl carbamates are described. When tested for inhibitory activity toward porcine pancreatic elastase, trypsin, and chymotrypsin, six compounds were found to specifically inhibit elastase without affecting the other two serine proteases. All the active inhibitors had an amino acid isostere at the P1 position. Kinetic studies indicated that the inhibition was competitive with Ki values ranging from 4.23 X 10(-5) to 2.4 X 10(-6) M. The degree of inhibition was found to be dependent on the specificity of the peptide chain for the extended subsites on the enzyme as well as on the nature of P1'. Preliminary work on one inhibitor indicates that the inhibition is reversible and proceeds via the rapid formation of a strong enzyme-inhibitor complex, followed by slow acylation of the serine residue on the active site of the enzyme. Peptidyl carbamates represent a novel class of elastase inhibitors.

Assessment of antiprotease activity of some carbamate derivatives.

Six carbamate derivatives were tested for inhibitory activity towards porcine pancreatic elastase, trypsin, and chymotrypsin. Only three esters that are isatoic anhydride derivatives were found to inhibit elastase competitively but nonspecifically. KI values for the best two inhibitors were determined from Dixon plots.

Peptidyl carbamate esters: a new class of specific elastase inhibitors.

A series of tripeptide carbamate esters were synthesized and tested for inhibitory activity towards porcine pancreatic elastase, trypsin and chymotrypsin. Two of these compounds specifically inhibited elastase [Ki = 4.25 x 10(-5)M and 3.00 x 10(-5)M], and exhibited no effect toward the other two serine proteases. These active tripeptidyl carbamates represent a novel class of specific elastase inhibitors.

G6PD Sendagi: a new glucose-6-phosphate dehydrogenase variant associated with congenital hemolytic anemia.

A new glucose-6-phosphate dehydrogenase (G6PD) variant associated with chronic nonspherocytic hemolytic anemia was discovered. It was found in a 2-year-old male who had a hemolytic crisis after an upper respiratory tract infection. The enzyme activity of the variant was 8.4% of that of the normal enzyme. The enzymatic characteristics were slower than normal anodal electrophoretic mobility, low Km G6P, normal Km NADP, increased utilization of substrate analogues, high Ki NADPH, decreased heat stability, and an alkaline pH optimum. From these results, this was considered to be a new variant and was designated G6PD Sendagi.

Binding metal elements in metallothionein fraction from liver of rat injected various metals.

Six elements, Cd, Co, Cu, Mn, Se and Zn, in the metallothionein fractions from liver of rat injected various metals (Cd, Co, Cu, Hg, Se and Zn) were analyzed by neutron activation analysis and were investigated metal binding of it. The concentrations of Cd and Zn were increased by administration of Cd and those of Co and Se were also increased by administration of the each element. On the contrary, the concentration of Cd and Cu were decreased by administration of Se. It may be considered that Co and Se are attached to metallothionein, if its protein is present and the presence of Se influence the binding of Cu and Cd to metallothionein, further it also influence Cd-thionein production.

Neutron activation analysis of normal and cadmium injected rat liver using ammonium pyrrolidinedithiocarbamate extraction.

A radiochemical group separation using APDC extraction was applied to the neutron activation analysis of normal and cadmium injected rat liver. In order to optimize determinations of induced radionuclides with various half lives, the gamma-ray spectra were obtained after various decay times. Eight elements, Cd, Co, Cu, Fe, Mn, Mo, Se and Zn, were determined from rat liver samples within 12 day after irradiation. Although Cd, Cu and Mo in normal rat liver could not be detected by nondestructive method, they could be determined after the extraction. The tendency was seen that the concentration of all the elements as mentioned above are increased by cadmium injection. In particular, zinc and copper exhibited high values.

Neutron activation analysis of biological materials by the monostandard method.

Instrumental neutron activation analysis by the monostandard method has been applied to the analyses of biological NBS standard reference materials; 1571 Orchard Leaves and 1577 Bovine Liver. Aluminum foils containing 0.100% gold or 2.00% cobalt were used as the monostandards. The gamma-ray spectral data were recorded on punched paper tape and were analyzed by a computer assisted data processing. The following 25 elements were determined: Al, Ca, Cl Cu, Mg, Mn, V (by short period irradiation), As, Ba, Br, Co, Cr, Cs, Eu, Fe, Hg, K, La, Na, Rb, Sb, Sc, Se, Sm and Zn (by long period irradiation). The results were compared with the certified values by NBS and the reported values in literatures to prove the reliability and accuracy of the monostandard method.