Use of naloxone in schizophrenic psychoses and manic syndromes

Since 1975, different morphinomimetic peptides have been isolated from hypophyseal-hypothalamic extracts: the pentapeptides methionine-enkephalin and leucine-enkephalin, and the longer peptides alpha-, beta- and gamma-endorphin. The primary structure of most of these peptides is also present in that of beta-lipotropin. The morphinomimetic properties of endorphins can be blocked with opiate-antagonists. In rats, moreover, the endorphins influence behavior which cannot be blocked with opiate antagonists. On the basis of the hypothesis that hyperactivity of endorphin systems may be involved in the pathogenesis of schizophrenia and manic syndromes, the effect of opiate antagonists on psychotic and manic symptoms has been examined in a number of clinical studies in the past few years. A transient therapeutic effect has been demonstrated in about 30% of the patients so treated. Our own double-blind controlled study of 5 schizophrenic and 5 manic patients in the context of a World Health Organization project failed to reveal any therapeutic effect after subcutaneous injection of 20 mg naloxone. The possible reasons of the negative results are discussed.     

In vitro activities of novel antifolate drug combinations against Plasmodium falciparum and human granulocyte CFUs

The potency of antimalarial dihydrofolate reductase inhibitors, alone and in synergistic combination with dihydropteroate synthetase inhibitors, against the Kenyan K39 strain of Plasmodium falciparum (pyrimethamine resistant) and against normal replicating human bone marrow cells in in vitro culture has been studied. Therapeutic indices and rank order of synergistic potency were derived. Trimethoprim, pyrimethamine, and the quinazolines WR159412 and WR158122 had the smallest therapeutic indices (1.39, 4.38, 2.56, and 90.0, respectively), while the three triazines clociguanil, WR99210, and chlorcycloguanil had the largest (3,562, 3,000, and 2,000, respectively). In rank order of decreasing activity against P. falciparum, the six most potent drug combinations were WR99210-dapsone, chlorcycloguanil-dapsone, WR158122-dapsone, WR159412-dapsone, WR159412-sulfamethoxazole, and chlorcycloguanil-sulfamethoxazole; pyrimethamine-sulfadoxine was the least potent combination. These experiments form a basis for the selection of rapidly eliminated antifolate combinations for further clinical testing.     

A simulated insect diet as a water source for quail: effects on body mass and reproduction

Compared with control birds receiving ad libitum free-water, the total water intake of male and female northern bobwhite declined when only mealworms were available as a source of water. Male northern bobwhite sustained tissue mass and reproductive function with mealworms as their only source of water. Female northern bobwhite could not sustain body, ovary, and oviduct mass, and rate of egg production with mealworms as their only source of water. We suggest that, without free-water, breeding females require a diet with a water:dry matter ratio of greater than 1:1.29 (> 44% water).     

Hepatotoxicity of anticholesterol, cardiovascular, and endocrine drugs and hormonal agents

Drugs in these categories may have effects on several organs in addition to the liver. For example, amiodarone may produce thyroid and corneal injury apart from or in addition to the phospholipidosis seen in the liver. Oral contraceptive steroids remain a rare but important concern for developing hepatic adenomas and possibly hepatocellular carcinoma, as well as a risk factor for developing Budd-Chiari syndrome in long-term users. Among the antihyperlipidemic agents, nicotinic acid, especially the sustained release formulations, may produce severe of even fatal hepatic injury. Increasing numbers of reports of hepatotoxicity from newer beta blockers and angiotensin-converting enzyme inhibitors require ongoing vigilance in patients receiving these medications.