Endotoxin Induces Severe Inflammatory Reactions with Necrosis at Sites Primed with Delayed-Type Hypersensitivity Reactions in Guinea Pigs

Guinea pigs immunized with Freund's complete adjuvant received challenge injection of the purified protein derivative of Mycobacterium tuberculosis in the flanks and the corneas to prepare delayed-type hypersensitivity (DTH) reactions. The animals were injected subcutaneously with lipopolysaccharide (LPS) or a synthetic lipid A (LA-15-PP). At the skin site primed with DTH reaction, increased swelling and hemorrhagic reaction followed by a definite necrotic reaction occurred. Severe corneal reactions were also observed in the animals. These findings indicate that bacterial endotoxin modulates DTH reactions and induces severe inflammatory reactions.     

The periodic loss of metabolically unstable DNA during replication of chromosomal DNA of CHO cells

The fate of ³H-thymidine incorporated into newly synthesized DNA of CHO cells was analyzed by either the estimation of the incorporated radioactivity per cell or sedimentation in alkaline sucrose gradient. Under conditions in which DNA synthesis proceeded continuously, of incorporated radioactivity was periodically lost and regained during a 90 min chase, corresponding to a cyclic change in the sedimentation profiles. When DNA synthesis was inhibited by hydroxyurea no cyclic change of the incorporated radioactivity was observed. The cyclic changes were regarded as the result of an actual metabolic change in³H-labelled DNA probaly joining to one of the newly formed sister strands of DNA and the loss of radioactivity seems to require active continued DNA synthesis.     

Cell-Free Synthesis of a Putative Precursor of Polygalacturonase in Tomato Fruits

By using a monospecific anti-polygalacturonase-2 antibody, a54K-dalton polypeptide was detected in in vitro translationproducts by a wheat germ cell-free translation system programmedwith polyadenylated RNA from ripe tomato pericarp tissue. Thisputative precursor of polygalacturonase was about 9K daltonslarger in molecular weight than polygalacturonase-2. (Received December 12, 1983; Accepted May 17, 1984)     

Sulfite suppresses the mutagenic property of coffee

The mutagenicity of instant and freshly brewed coffee on Salmonella typhimurium TA100 and TA98 without S9 mix was inactivated by sodium sulfite. Sulfite ion at a dose of 200 ppm almost completely inactivated the mutagenicity of coffee made in the ordinary way (5-15 mg dry weight/ml). Sodium bisulfite and potassium metabisulfite had similar effects. On the contrary, L-ascorbic acid enhanced the mutagenicity of coffee. Sodium sulfite also inactivated the phage-inducing activity of coffee in inductest III. Sodium sulfite completely suppressed the mutagenicities of 1,2-dicarbonyls, namely diacetyl and glyoxal. Diacetyl is present in coffee, beer, butter and other foods and drinks. Because sodium sulfite, sodium bisulfite and potassium metabisulfite are widely used as food additives, they should be useful in reducing the levels of mutagens in foods.     

Fluctuations in pulmonary fibrin decomposing activities (plasmin and non-plasmin activities) in an endotoxin DIC model in rats

Non-plasmin fibrinolysis enzyme was extracted from the lung and spleen of conventional rats (Thrombos. Haemostas., 1979), although the enzyme was not found in germfree rats, suggesting the possibility that the enzyme may participate in the defence mechanism of the body. The present study was made in an attempt to determine the behavior of non-plasmin fibrinolysis enzyme of the lung tissue in the DIC model of conventional rats induced by a single injection of bacterial endotoxin. The plasminogen-activator activity of the lung tissue, and the fibrinogen level, platelet count, urea nitrogen and plasminogen-activator activity in the blood were also measured. Examination of the lung tissue in the DIC rats indicated a remarkable increase in non-plasmin fibrinolysis activity and a disappearance of plasminogen-activator activity. Inhibitor studies using t-AMCHA and DFP demonstrated that the increased non-plasmin fibrinolysis activity was not derived from activated plasmin, but from serine protease. The disappearance of plasminogen-activator activity in the lung and increase of plasminogen-activator activity in the blood suggested a release of the activator from the lung into the blood due to the endotoxin injection.     

Strain difference in expression of the adult-type polycystic kidney disease gene, pcy, in the mouse

DBA/2FG-pcy and C57BL/6FG-pcy congenic strains were established by transferring the polycystic kidney disease gene, pcy, to DBA/2 and C57BL/6 mice. We carried out pathological and hematological examinations of these strains at 4, 8, 16 and 30 weeks of age. In DBA/2FG-pcy mice more than 8 weeks of age, macroscopic renal cysts were observed on the surface of both kidneys. Their kidneys weight was significantly greater than in DBA/2 mice at all ages examined. Microscopic renal cysts were evenly distributed at 4, 8 and 16 weeks of age. At 30 weeks of age, the kidneys were filled with numerous polycysts. In C57BL/6FG-pcy mice, no macroscopic renal cysts were found until the animals were 30 weeks old, and the weight of their kidneys was greater than in B6 mice of the same age. From 8 weeks of age on, a limited number of microscopic renal cysts was observed, and many renal cysts were found adjacent to the enlarged Bowman's capsules. With age, the red blood cell count and hematocrit level decreased while the platelet count increased in both strains, with greater changes occurring in DBA/2FG-pcy mice than in C57 BL/6FG-pcy mice. These findings demonstrate that polycystic kidney disease exhibits strain differences in animals with a DBA/2 and C57BL/6 background. Our results suggest that phenotypic expression of the pcy gene in the mouse depends on genetic background, and that variations in the severity of human polycystic kidney disease may be explained, at least in part, by individual differences in genetic background.     

Prostaglandin E2 Activates Ca2+ Channels in Bovine Adrenal Chromaffin Cells

We have demonstrated that prostaglandin E2 (PGE2) treatment of bovine adrenal chromaffin cells results in a sustained elevation of intracellular Ca2+ concentration ([Ca2+]i) in these cells. Because the continued elevation of [Ca2+]i was dependent on extracellular Ca2+ concentration, it can be assumed that the PGE2-induced [Ca2+]i increase is due, at least in part, to an opening of membrane Ca2+ channels. In this study, we used electrophysiological methods to examine the mechanism of the PGE2-induced [Ca2+]i increase directly. Puff application of PGE2 to the external medium resulted in a prolonged depolarization in about half of the chromaffin cells examined. In whole-cell voltage-clamp recordings, an increase in inward current was observed over a 6-7 min period following bath application of PGE2 (greater than or equal to 10 microM), even in the absence of external Na+. This inward current was abolished when the recordings were made with the cells in a Ca2(+)-free medium, but it was not inhibited by Mn2+, a blocker of voltage-dependent Ca2+ channels. In cell-attached patch-clamp configuration, PGE2 produced an increase in the opening frequency of inward currents. The reversal potential of the PGE2-induced currents was about +40 mV, which is close to the reversal potential of the Ca2+ channel. The opening frequency was not affected by membrane potential changes. In inside-out patch-clamp configuration, inositol 1,4,5-trisphosphate (2 microM) added to the cytoplasmic side activated the Ca2(+)-channel currents, but PGE2 was ineffective when applied to the cytoplasmic side. These results suggest that PGE2 activates voltage-independent Ca2+ channels in chromaffin cells through a diffusible second messenger, possibly inositol 1,4,5-trisphosphate.