Modulatory influence of sodium 2-propenyl thiosulfate from garlic on cyclooxygenase activity in canine platelets: possible mechanism for the anti-aggregatory effect.

We previously found that sodium 2-propenyl thiosulfate (2PTS) has an anti-aggregatory effect in vitro on both canine and human platelets at relatively low concentrations, but the extent of aggregation tends to return to the control level at high concentrations. To clarify the mechanism of this modulatory influence of 2PTS on the aggregation of platelets, we investigated the effects of 2PTS on cyclooxygenase (COX) activity and the reduced glutathione (GSH) concentration in canine platelets. Platelet COX activity was inhibited by 2PTS in a dose-dependent manner up to 0.1 mM, but tended to return to the control level at 1 mM. In contrast, the platelet GSH concentration decreased in a dose-dependent manner after treatment with 2PTS and a significant decrease was observed at 0.1 mM (P<0.05) and 1 mM (P<0.001). Furthermore, the activity of purified COX-1 was directly inhibited by addition of GSH in a dose-dependent manner. From these results, we conclude that the 2PTS-induced inhibition of platelet aggregation occurs as a result of inhibition of COX activity. Additionally, 2PTS may have a modulatory effect on platelet aggregation by affecting the platelet GSH concentration.

Acceleration of superoxide generation in polymorphonuclear leukocytes and inhibition of platelet aggregation by alk(en)yl thiosulfates derived from onion and garlic in dogs and humans.

We recently identified sodium n-propyl thiosulfate (NPTS) and sodium 2-propenyl thiosulfate (2PTS) from boiled onion and garlic, respectively, as causative agents of hemolytic anemia in dogs. We present here data concerning the effects of these alk(en)yl thiosulfates on superoxide (O(2)(-)) generation in peripheral polymorphonuclear leukocytes (PMNs) and on adenosine 5'-diphosphate (ADP)-induced platelet aggregation in dogs and humans in vitro. Both NPTS and 2PTS increased O(2)(-) generation significantly (P<0.05 at 1mM NPTS, P<0.005 at 0.1 and 1mM 2PTS) and reduced its reaction time significantly (P<0.05 between 0.01 and 1mM NPTS and at 1mM 2PTS) in canine PMNs stimulated by phorbol 12-myristate 13-acetate, compared with the control without alk(en)yl thiosulfates. However, a tendency to return to the control level was observed at 10mM of the alk(en)yl thiosulfates in both O(2)(-) generation and its reaction time. Although NPTS and 2PTS did not exert any significant effect on the O(2)(-) generation in human PMNs, 2PTS reduced its reaction time significantly (P<0.05) at 1 and 10mM compared with the control, showing that 2PTS accelerated O(2)(-) generation in human PMNs. The difference in effects on O(2)(-) generation may be due to that in susceptibility to alk(en)yl thiosulfates between canine and human PMNs. On the other hand, NPTS and 2PTS were shown to significantly inhibit ADP-induced platelet aggregation at 0.01mM (P<0.01) in canine platelets and at 0.001-0.1mM (P<0.05) in human platelets. In contrast, the maximal aggregation percentage returned to the control level at 1mM of alk(en)yl thiosulfates in both canine and human platelets. From these results, we conclude that NPTS and 2PTS have the potential to promote immune functions and prevent cardiovascular diseases.

Hematologic changes associated with the appearance of eccentrocytes after intragastric administration of garlic extract to dogs.

OBJECTIVE: To determine whether dogs given garlic extract developed hemolytic anemia and to establish the hematologic characteristics induced experimentally by intragastric administration of garlic extract. ANIMALS: 8 healthy adult mixed-breed dogs. PROCEDURE: 4 dogs were given 1.25 ml of garlic extract/kg of body weight (5 g of whole garlic/kg) intragastrically once a day for 7 days. The remaining 4 control dogs received water instead of garlic extract. Complete blood counts were performed, and methemoglobin and erythrocyte-reduced glutathione concentrations, percentage of erythrocytes with Heinz bodies, and percentage of eccentrocytes were determined before and for 30 days after administration of the first dose of garlic extract. Ultrastructural analysis of eccentrocytes was performed. RESULTS: Compared with initial values, erythrocyte count, Hct, and hemoglobin concentration decreased to a minimum value on days 9 to 11 in dogs given garlic extract. Heinz body formation, an increase in erythrocyte-reduced glutathione concentration, and eccentrocytes were also detected in these dogs. However, no dog developed hemolytic anemia. CONCLUSIONS AND CLINICAL RELEVANCE: The constituents of garlic have the potential to oxidize erythrocyte membranes and hemoglobin, inducing hemolysis associated with the appearance of eccentrocytes in dogs. Thus, foods containing garlic should not be fed to dogs. Eccentrocytosis appears to be a major diagnostic feature of garlic-induced hemolysis in dogs.

The cause of the predilection of Babesia gibsoni for reticulocytes.

This study was conducted to determine why Babesia gibsoni replicates well in reticulocytes. First, B. gibsoni was cultivated in resealed erythrocyte ghosts loaded with either erythrocyte or reticulocyte lysate, and in reticulocyte ghosts loaded with either erythrocyte or reticulocyte lysate. The parasites multiplied well in the erythrocyte or reticulocyte ghosts loaded with reticulocyte lysate compared to the other resealed cells loaded with erythrocyte lysate. Second, the parasites were cultivated in erythrocytes in culture medium supplemented with either erythrocyte or reticulocyte lysate. The parasites multiplied better in reticulocyte lysate-containing cultures than in erythrocyte lysate-containing cultures. Finally, the parasites were cultivated in erythrocytes in culture medium supplemented with glutamate, aspartate, asparagine, glycine, isoleucine, proline, taurine or GSH, which were present in higher concentrations in reticulocytes than in erythrocytes. Supplementation of the culture medium with glutamate and GSH resulted in enhancement of the multiplication of the parasites, while the other amino acids did not enhance the multiplication. These results indicated that the high levels of the multiplication of B. gibsoni in reticulocytes are partly due to the high concentrations of glutamate and GSH in reticulocytes.

Rumen bacteria are involved in the onset of onion-induced hemolytic anemia in sheep.

The mechanism of onion-induced hemolytic anemia in ruminants was investigated. The ether-extract obtained from the mixture of rumen fluid and onion juice incubated at 38.5 degrees C for 9 hr induced oxidative damage in sheep erythrocytes in vitro, indicating the production of certain oxidants in the mixture. The increase of the oxidative effect in the mixture was inhibited completely by the removal of rumen microorganisms and partly by treatment with antibiotics and by oxygen gas. The sheep fed onions (50 g/kg body weight/day) for 15 days developed more severe Heinz body hemolytic anemia than did the sheep fed the equivalent amount of onions with 5 g/day ampicillin sodium salt. The results indicated that certain rumen bacteria appear to be involved in the onset of onion-induced hemolytic anemia in sheep.

Reduced glutathione accelerates the oxidative damage produced by sodium n-propylthiosulfate, one of the causative agents of onion-induced hemolytic anemia in dogs.

The oxidative effects of sodium n-propylthiosulfate, one of the causative agents of onion-induced hemolytic anemia in dogs, were investigated in vitro using three types of canine erythrocytes, which are differentiated by the concentration of reduced glutathione and the composition of intracellular cations. After incubation with sodium n-propylthiosulfate, the methemoglobin concentration and Heinz body count in all three types of erythrocytes increased and a decrease in the erythrocyte reduced glutathione concentration was then observed. The erythrocytes containing high concentrations of potassium and reduced glutathione (approximately five times the normal values) were more susceptible to oxidative damage by sodium n-propylthiosulfate than were the normal canine erythrocytes. The susceptibility of the erythrocytes containing high potassium and normal reduced glutathione concentrations was intermediate between those of erythrocytes containing high concentrations of potassium and reduced glutathione and normal canine erythrocytes. In addition, the depletion of erythrocyte reduced glutathione by 1-chloro-2, 4-dinitrobenzene resulted in a marked decrease in the oxidative injury induced by sodium n-propylthiosulfate in erythrocytes containing high concentrations of potassium and reduced glutathione. The generation of superoxide in erythrocytes containing high concentrations of potassium and reduced glutathione was 4.1 times higher than that in normal canine erythrocytes when the cells were incubated with sodium n-propylthiosulfate. These observations indicate that erythrocyte reduced glutathione, which is known as an antioxidant, accelerates the oxidative damage produced by sodium n-propylthiosulfate.

Induction of onion-induced haemolytic anaemia in dogs with sodium n-propylthiosulphate.

The haemolytic effect of sodium n-propylthiosulphate, which had been isolated from boiled onions, was studied to determine whether it could be one of the agents responsible for induced haemolytic anaemia in dogs. The oral administration of 500 mumol/kg bodyweight of the compound to dogs resulted in a haemolytic anaemia associated with an increase of Heinz body formation in erythrocytes, which was more severe in dogs with the hereditary condition which results in erythrocytes with high concentrations of reduced glutathione and potassium than in normal dogs. In the affected dogs there was a 10-fold increase in the concentration of oxidised glutathione in their erythrocytes 12 hours after the administration of the compound, whereas in normal dogs there was almost no change.

Hemolytic anemia in wild seaducks caused by marine oil pollution.

Clinico-pathological examinations were conducted on wild white-winged scoters (Melanitta fusca) contaminated with fuel oil (Bunker C oil) from a capsized cargo ship in February 1993 in Japan. The erythrocyte count, hemoglobin concentration and hematocrit value in the oiled seaducks all were decreased and numerous immature erythrocytes were observed in blood smears. In addition, hemosiderosis was observed in the liver, kidney, and lung of some birds. We propose that the sea-ducks suffered from hemolytic anemia induced by ingestion of oil, which occurs when the birds preen their oiled plumage.

Erythrocyte ALA-d activity in experimentally lead-poisoned ducks and its change during treatment with disodium calcium EDTA.

To determine useful procedures for the diagnosis and prognosis of lead poisoning in waterfowl caused by ingestion of lead pellets, erythrocyte delta-aminolevulinic acid dehydratase (ALA-d) was investigated in experimentally lead-poisoned ducks. A highly positive correlation was observed between the concentration of blood lead and the ALA-d activity ratio (the ratio of activated:non-activated enzyme activity) in those birds given seven lead pellets (3 mm diameter). The ALA-d activity ratio rapidly increased after the administration of lead pellets, but began to fall immediately after the initiation of disodium calcium ethylenediamine tetra-acetate (CaEDTA) therapy which resulted in a rapid decrease in the concentration of lead in the blood of these birds. In contrast, the ALA-d activity remained inhibited even after blood lead levels began to decrease following treatment. These results demonstrated that the ALA-d activity ratio is a very useful and sensitive indicator for the diagnosis and evaluation of therapeutic effects after lead poisoning in waterfowl.

Treatment of lead poisoning in wild geese.

Twenty-seven wild geese (Anser albifrons) suffering from lead poisoning caused by ingestion of lead shot were treated with disodium calcium ethylenediaminetetraacetate. The concentration of lead in blood ranged from 0.4 to 23.0 micrograms/ml, with a mean concentration of 5.6 micrograms/ml. In 22 of the birds, 1 to 48 lead pellets (mean, 10.5 pellets/bird) were seen on radiographs of their gizzards. Eleven of 27 birds recovered 3 to 8 weeks after the initiation of treatment. In the birds that recovered, the lead pellets were rapidly eroded as the birds recovered their appetites in response to treatment, and disappeared radiographically between treatment days 17 and 52. The birds that did not survive died within 4 weeks, despite decreased concentrations of lead in blood. Of these 16 birds, 15 had radiographic evidence of impaction of the proventriculus at the first examination and no evidence of resolution of the impaction at the time of death. In contrast, only 2 of the 11 geese that recovered had impaction of the proventriculus at the time of admission. Thus, the condition of the proventriculus seems to be the first consideration to evaluate in the prognosis of lead poisoning in geese.