Insect glutathione S-transferase: Separation of transferases from fat bodies of American cockroaches active on organophosphorus triesters

Several glutathione S-transferases which catalyze the conjugation of reduced glutathione with organophosphorus triesters were separated from fat bodies of adult female American cockroaches, Periplaneta americana (L.). Two transferases (I, V) were active on diazinon and three transferases (II, III, IV) were active on methyl parathion. The transferase (I) active on the pyrimidinyl moiety of diazinon was distinguishable from the other transferases on the O-methyl portion of methyl parathion, as shown by chromatographic properties, and additionally it was almost inactive or less active on 3,4-dichloronitrobenzene, methyl iodide, p-nitrobenzyl chloride, trans-cinnamaldehyde, and 1,2-epoxy-3-(p-nitrophenoxy)propane. Transferase II had high activities with “aryl” and “aralkyl” compounds, transferase III with “epoxide” and “alkene,” and transferase IV with “alkyl,” “aryl,” and “aralkyl” compounds. This indicated that the transferases had overlapping substrate specificities. The molecular weight was 35,000–37,000 for both of the enzymes active on methyl parathion and diazinon. The pH optima with methyl parathion and diazinon were about 8.5 and 6.5, respectively. At a glutathione concentration of 5 mM, Michaelis constants were 0.28 and 0.13 mM for methyl parathion and diazinon, respectively.     

Hepatic morphology and effects of intravenous injection of sodium propionate on plasma propionate and glucose in fed and fasted dairy cattle

Sodium propionate (3 mmol/kg) was injected IV into 8 nonlactating dairy cows before and after 6 days (144 hours) of fasting. During fasting, long-chain fatty acids in plasma increased from 0.30 +/- 0.05 (SE) mM to 1.09 +/- 0.15 mM (P less than 0.05). Liver fat increased from 0.5 +/- 0.3% to 9.3 +/- 1.7% (P less than 0.05). Half-life of injected sodium propionate increased significantly (P less than 0.05) from 7.6 +/- 0.5 minutes to 10.1 +/- 1.0 minutes during fasting. Sulfobromophthalein half-life did not change significantly (3.8 +/- 0.79 minutes to 5.3 +/- 1.3 minutes). Increases in plasma glucose concentrations after propionate loading were significantly less during fasting than during feeding. Thus, the change in glucose concentration served as an indicator of hepatic conversion of propionate to glucose. Increases in glucose concentration of less than 2 mM at 30 minutes after propionate loading indicated that liver function was altered in nonlactating dairy cows.     

The clinical administration of the opioid antagonist naloxone in dogs

The short introduction gives a review on the complex of exogen and endogen opioids and their receptors as well as on their pharmacodynamics, pharmacokinetics and toxicity of naloxone. The clinical efficacy of naloxone as an opioid antagonist is described. Applications of naloxone for the dog are specified: antagonisation of etorphine, morphine, levomethadone and fentanyl, antagonisation of exogen and endogen opioids in puppies and treatment of lactomania in the bitch. The mean effective dose to antagonize morphines is 0.003 mg/kg bodyweight. If persisting analgesia is indicated the dose of naloxone in titrating steps in 0.001 mg/kg bw. To antagonize postpartal hypoxia in puppies 0.02 mg per animal naloxone have to be injected. For treatment of lactomania a dose of 0.01 mg/kg bodyweight twice a day for a couple of days is recommended. The clinical effectivity of naloxone is proved doubtlessly. Compatibility and safety are very high.