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At least 19 recordsLinked to original sources
PubMed1979

Discriminant--analytical investigation on the structural dependence of hyperglycemic and hypoglycemic activity in a series of substituted o-toluenesulfonylthioureas and o-toluenesulfonylureas.

The influence of a series of substituted o-toluenesulfonylthioureas and o-toluenesulfonylureas on the level of blood sugar was investigated in rats. According to the observed response the compounds were divided into three classes corresponding to hypoglycemic, hyperglycemic, and no activity. The distribution of the compounds over these classes can be described by discriminant functions using substituent constants, RM values, and indicator variables. Most important for the separation of classes are hydrophobic and/or steric properties as well as the presence or absence of the thiomide group. The results indicate that two different mechanisms of action with opposite effect overlap in the case of the series studied.

Animals↗
PubMed1975

Combination effect of bis(3-methylsulfonyloxypropyl)amide and 6-mercaptopurine on AH-60C and AH-109A.

Survival period of rats bearing ascites hepatoma, AH-60C, which was less sensitive to bis (3-methylsulfonyloxypropyl)amine (864-T) and 6-mercaptopurine each alone, was prolonged by the combined treatment with these two agents. Two or 3 rats in groups of 12 animals each survived over 60 days by this combined therapy beginning from day 0. In AH-109A, which was insensitive to 6-mercaptopurine, the group treated with this combination did not survive longer than that with 864-T alone.

Animals↗
PubMed1977

Antitumor effect of 1,1'-polymethylene-bis (1-nitrosourea) and related compounds.

Polymethylene-bis(1-nitrosourea), polymethylene-bis(1-nitroso-3-nitroguanidine), and polymethylene-bis(1-nitroso-p-toluenesulfonamide) derivatives were tested for antitumor effect against rat ascites hepatoma AH-13 and mouse leukemia L-1210. Bisnitrosoureas were effective against AH-13 and L-1210, bisnitrosoguanidines were effective against AH-13 alone, and bisnitrosotoluene-sulfonamides were ineffective against both tumor lines. Of all these compounds, 1,1'-ethylene-bis(1-nitrosourea) (EBNU) was the most effective. The antitumor effect of EBNU was compared with that of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). Intraperitoneal administration of EBNU according to the schedule, day 1, days 1 and 5, and days 1, 5, and 9 after intraperitoneal inoculation of L-1210 showed marked prolongation of host survival, although the effective doses used were a few times higher than those used in BCNU to obtain a similar effect. The minimum effective dose (MED) of EBNU on AH-13 cells was estimated as 1 mg/kg, which was 10 times less than that of BCNU, suggesting that EBNU was more effective than BCNU against AH-13.

Animals↗
PubMed1976

Beta-glucuronidase activity of Yoshida ascites hepatomas of different drug-sensitivity and its change after treatment of host rats with various anticancer agents.

Change in beta-glucuronidase activity of six Yoshida ascites hepatomas was examined after treatment of host rats with one of 12 anticancer agents. The hepatomas, AH-66F, AH-130, AH-109A, AH-60C, and AH-44, in decreasing order showed more or less distinct increase in beta-glucuronidase activity after treatment of the rats with Nitromin, Endoxan, 864-T, Carbazilquinone, Mitomycin-C, Toyomycin, Daunomycin, Neocarzinostatin, vincristine sulfate, 5-fluorouracil, or cytosine arabinoside only when the cytological effect was positive. Moreover, degree of the increase was generally correlated with that of cytological effect. Bleomycin was ineffective either enzymically or cytologically. AH-66 was insensitive to any of the agents tested in increasing beta-glucuronidase activity and showed only a very slight cytological response to some of the agents. Acid deoxyribonuclease behaved like beta-glucuronidase but to a lesser extent. The above order of drug sensitivity of the hepatomas was not in parallel with that of normal beta-glucuronidase level, which also did not correlate with the life span of host rats.

Animals↗
PubMed1976

Bovine spleen cathepsin B1 and collagenolytic cathepsin. A comparative study of the properties of the two enzymes in the degradation of native collagen.

Bovine spleen cathepsin B1 and collagenolytic cathepsin were separated by chromatography on Amberlite IRC-50 and collagenolytic cathepsin was partially purified by chromatography on DEAE-Sephadex (A-50). 2. Collagenolytic cathepsin degraded insoluble tendon collagen maximally at pH 3.5 and 28 degrees C; mainly alpha-chain components were released into solution. At 28 degrees C the telopeptides in soluble skin collagen were also cleaved to yield alpha-chain components. Collagenolytic cathepsin was thus similar to cathepsin B1 in its action against native collagen, but mixtures of these two enzymes exhibited a synergistic effect. 3. The addition of thiol-blocking compounds produced similar inhibition of collagenolytic cathepsin and cathepsin B1. The enzyme responded similarly to all other compounds tested except to 6-aminohexanoic acid, when collagenolytic cathepsin was slightly activated and cathepsin B1 was almost unaffected. 4. Leupeptin, which is a structural analogue of arginine-containing synthetic substrates, inhibited collagenolytic cathepsin as effectively as cathepsin B1. Collagenolytic cathepsin was shown to retain a low residual activity against alpha-N-benzoyl-DL-arginine p-nitroanilide during purification which was equivalent to 0.2% of the activity of cathepsin B1. 5. Cathepsin B1 and collagenolytic cathepsin could not be separated by affinity chromatography on organomercurial-Sepharose 4B. The two enzymes could be resolved on DEAE-Sephadex (A-50) and by isoelectric focusing in an Ampholine pH gradient. The pI of the major cathepsin B1 isoenzyme was 4.9 and the pI of collagenolytic cathepsin was 6.4. 6. From chromatography on Sephadex G-75 (superfine grade) the molecular weights were calculated to be 26000 for cathepsin B1 and 20000 for collagenolytic cathepsin. The difference in molecular weight was confirmed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis.

2,2'-Dipyridyl↗
PubMed1976

Chemical modification of two tryptophan residues abolishes the catalytic activity of aminoacylase.

1) The reaction of 1 H-diazotetrazole and N-bromosuccinimide with aminoacylase was studied under different conditions. A tenfold molar excess of 1 H-diazotetrazole (2 X 10(-4) M) at pH 5.5 abolishes the catalytic activity of the enzyme while modifying only two tryptophan residues. No other amino acid reacted under these conditions as tested by amino acid analysis. 2) With a 40-fold molar excess of N-bromosuccinimide (8 X 10(-4)M) at pH 5.0, two tryptophan residues of the enzyme were oxidized with complete loss of activity. Under these conditions no significant cleavage of the polypeptide chain was observed. Neither tyrosine nor histidine was modified by this reagent, up to a 100-fold molar excess. 3) Substrates and reversible (N-tosylalanine) and irreversible (TosPheCH2Cl) inhibitors of the enzyme do not protect the two reactive tryptophans against the modification reagents. Under more drastic conditions, lysine, tyrosine and histidine residues are also modified by the reagents.

Alanine↗
PubMed1978

Intestinal secretion of sulphanilic acid by the isolated mucosa of guinea pig jejunum.

Tissue uptake and transepithelial permeation of 35S-sulphanilic acid were studied in the isolated guinea pig jejunal mucosa. Methoxy-3H-inulin added simultaneously served as a marker for the extracellular space and permeability of paracellular shunt pathways in the preparation. The uptake of sulphanilic acid from the blood side exceeded that from the luminal side 4--7 fold. The permeation of the acid was strongly correlated to the permeation of inulin. At 5 micrometer and 2.5 mM sulphanilic acid under aerobic conditions, the regression lines for the permeation from lumen to blood pass almost through the origin, while the regression lines for the permeation from blood to lumen intersect the ordinate at a positive Y-value. In anaerobiosis, at 25 mM sulphanilic acid, or with addition of p-toluene sulphonic acid only one regression line is obtained for the permeation in both directions. It is concluded that besides a permeation of sulphanilic acid across inulinpermeable shunt pathways an active transport system exists, which transfers the acid from the blood to the luminal side. This system is saturable, depends on aerobic energy and exhibits mutual inhibition by a structurally related compound. The results are comparable to those previously obtained with cardiac glycosides and quaternary ammonium compounds, in the same preparation. Thus, the intestinal mucosa is able to secrete the same classes of compounds which are secreted by the liver and the kidney.

Aerobiosis↗