Naphthylisoquinoline alkaloids exhibit strong growth-inhibiting activities against Plasmodium falciparum and P. berghei in vitro--structure-activity relationships of dioncophylline C.

The growth-inhibiting activities of naturally occurring naphthylisoquinoline alkaloids against asexual blood stages of Plasmodium falciparum (NF 54, clone A1A9) and P. berghei (Anka) were studied in vitro. Three of the alkaloids [7-epi-dioncophylline A (8b), dioncolactone A (4), and 5'-O-demethyl-8-O-methyl-7-epidioncophylline A (11)] displayed good activities against both parasites, with median inhibitory concentrations (IC50) of 1-5 micrograms/ml. Dioncophylline C (2), however, was even better, with IC50 of 0.014 microgram/ml (P. falciparum) and 0.015 microgram/ml (P. berghei) and therefore regarded as a promising lead for studies of structure-activity relationships. The free N- and 8-OH-functions were shown to be prerequisites for the outstanding activity of this molecule against P. falciparum, the presence of at least one free phenolic OH-function appearing to be essential for any activity. Initial experiments with derivatives of ancistrocladine (1) show that, in contrast to 2, N-derivatization of this alkaloid leads to increased activity against P. falciparum.

Making a presumptive diagnosis of urinary tract infection by using a urinalysis performed in an on-site laboratory.

The purpose of our study was to characterize the utility of certain elements of urinalysis, singly or in combination, in identifying children with urinary tract infections (i.e., positive findings on urine culture). Laboratory results for urine specimens subjected to both urinalysis and culture in an on-site outpatient clinic (office) laboratory during a 36-month period were reviewed. All specimens were collected by one of three methods (the midstream void technique, urethral catheterization, or suprapubic aspiration of urine) from children with symptoms to assist in documenting a possible urinary tract infection. Specimen processing by certified technologists was initiated within 10 minutes of collection. Sensitivity, specificity, and positive and negative predictive values were determined for each test or combination of tests. Of 689 specimens, 102 (14.8%) had positive culture results. The combination of dipstick analysis (leukocyte esterase and nitrite tests) and of microscopic examination for bacteria had a sensitivity of 100% and a negative predictive value of 100%. The nitrite test had a specificity of 100% and a positive predictive value of 100%. We conclude that, when properly collected specimens are evaluated promptly by certified technologists, the rate of accuracy in detecting or ruling out a urinary tract infection (i.e., positive findings on urine culture) with certain elements of the urinalysis is high.