Reactive oxygen production against malaria--a potential cancer risk factor.

In response to malaria infection, phagocytes, such as macro-phages and neutrophils, produce superoxide and thence the other reactive oxygen species (ROS) with which to kill the parasites. Excess ROS is normally eliminated by the body's natural scavenger molecules; however, in the event of a vast excess of ROS, as may be the case in acute as well as chronic malaria patients, the natural scavengers may be overwhelmed. We hypothesize that unscavenged ROS in malaria patients causes DNA damage in normal host cells which, if unrepaired or incorrectly repaired, could result in oncogene activation and eventually lead to cancer. An epidemiologic study may be warranted in malaria-endemic regions to investigate the possible relationship between malaria infection and cancer risk.

An oxytocic extractive from a West African cucurbit. Studies on west African medicinal plants. 8.

PIP: In south-east Nigeria the plant Mormordica cabrei, of the Cucurbitac eae family, is believed to be an abortifacient. A crude methanol-soluble extractive of the fruit, branches, and roots of the plant caused an intense spasm when administered to pregnant and non-pregnant uterine tissue, in vitro. The physiologically active principle appears to be cucurbit glycosides.^ieng

Acetylation polymorphism and leprosy.

The sulfones are the drug of choice in the treatment of leprosy, with dapsone as the clear favorite. The major route for dapsone metabolism leading to its inactivation and excretion is via acetylation by hepatic N-acetyl transferase (NAT), as is the case with isoniazid (INH) and sulfamethazine (SMZ). The enzyme is known to exhibit genetic polymorphism. The object of the present study is mainly to determine the incidence of acetylator phenotype in a population of leprosy patients with a view to evaluating the degree of association, if any, between phenotype and the disease. Obviously a knowledge of the incidence of the phenotypes may provide a valuable contribution to the institution of more rational and successful therapy. In the normal or control subjects, as well as in the leprosy patients, the frequency distribution histograms of the percentage acetylsulfamethazine in urine and serum samples are bimodal, and this indicates the existence of a genetic polymorphism. Based on the bimodality, individuals were classified as either "rapid" or "slow" acetylators, and the incidence of the slow acetylator phenotype of about 51% was observed in the leprosy population. This gives a relatively high incidence of the allele controlling the slow acetylator (q = 0.73). Although there is evidence that the mean percentage of SMZ acetylated in leprosy patients of the slow acetylator phenotype is significantly higher than that observed for the same phenotype in the controls (t = 4.86, P less than 0.02), statistical analyses show that there is no association between the slow acetylator phenotype and the disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of oxygen free radical scavengers on the membrane myoinositol dehydrogenase of Bacillus pumilus strain 5.

Micromolar amounts of superoxide dismutase (SOD) or parabenzoquinone (PBQ) inhibit the membrane-bound myoinositol dehydrogenase of Bacillus pumilus strain 5 in the mode of this enzyme transferring electrons to 2,6-dichlorophenol indophenol (DCPIP). The inhibition trends are similar to those reported earlier by us for the inhibition by mannitol and benzoate. We postulate that the transfer of electrons from the enzyme to DCPIP involves in its rate-limiting step, a catalytic intermediate in the nature of superoxide (O2-) and/or hydroyl free radical (OH.). Scavenging of any one or both of these radicals, therefore, inhibits the electron transfer reaction. PBQ serves as an electron sink in the reaction preventing the reduction of DCPIP.

Erythrocyte membrane enzymes in sickle cell anemia. 2. Acetylcholinesterase and ATPase activities.

The activity level of acetylcholinesterase in the erythrocytes of 32 patients homozygous for sickle cell anemia was determined and compared with that of normal AA controls as well as with that of AS individuals. Acetylcholinesterase activity was markedly higher in erythrocyte membrane from SS individuals than in those from AS individuals or AA controls. Additionally, ATPase activities were also significantly higher in sickle cell erythrocytes as compared to normal cells. These higher values of acetylcholinesterase and ATPase activities in SS erythrocytes may be explained as a consequence of the abnormally high cation levels in sickle cell erythrocytes.