SATE (aryl) phosphotriester series. I. Synthesis and biological evaluation

Synthesis and biological activities of several phosphotriester derivatives of 3'-azido-2',3'-dideoxythymidine (AZT) bearing a S-pivaloyl-2-thioethyl (tBuSATE) group and aryl residues derived from L-tyrosine are reported. All compounds showed marked anti-HIV activity in thymidine kinase-deficient CEM cells demonstrating their ability to deliver intracellularly the parent 5'-mononucleotide.     

SATE (aryl) phosphotriester series. II. Stability studies and physicochemical parameters

The stability of phosphotriester derivatives of 3'-azido-2',3'-dideoxythymidine (AZT) bearing a S-pivaloyl-2-thioethyl (tBuSATE) group and various aryl residues derived from L-tyrosine was evaluated in biological media. The results demonstrate that such compounds give rise to intracellular delivery of the parent mononucleotide through esterase and phosphodiesterase hydrolytic steps, successively.     

A taxonomic review of Iris L. series Unguiculares (Diels) Lawrence

DAVIS, A. P. & JURY, S. L., 1990. A review of Iris L. series Unguiculares (Diels) Lawrence (Iridaceae) . The morphology, pollen, chromosomes and distribution of these plants are discussed and a new systematic account of the series is given.     

Hydroporphyrins of the meso-tetra(hydroxyphenyl)porphyrin series as tumour photosensitizers.

Although folate deficiency and increased requirements for folate are observed in most alcoholics, the possibility that acetaldehyde generated from ethanol metabolism may increase folate catabolism has not been previously demonstrated. Folate cleavage was studied in vitro during the metabolism of acetaldehyde by xanthine oxidase, measured as the production of p-aminobenzoylglutamate from folate using h.p.l.c. Acetaldehyde/xanthine oxidase generated superoxide, which cleaved folates (5-methyltetrahydrofolate greater than folinic acid greater than folate) and was inhibited by superoxide dismutase. Cleavage was increased by addition of ferritin and inhibited by desferrioxamine (a tight chelator of iron), suggesting the importance of catalytic iron. Superoxide generated from the metabolism of ethanol to acetaldehyde in the presence of xanthine oxidase in vivo may contribute to the severity of folate deficiency in the alcoholic.     

Descriptions of Lutzomyia (Evandromyia) georgii n. sp. and a synopsis of the series infraspinosa (Diptera: Psychodidae)

Lutzomyia georgii n. sp. and the female of L. tarapacaensis in the Series infraspinosa of the subgenus Evandromyia are described, from specimens collected in rainforest in the north of the State of Pará, Brazil. The new species was taken together with five other Evandromyia species including L. infraspinosa (sensu strictu) in the same locality. L. georgii has previously been confused with both L. begonae and L. infraspinosa, whereas L. tarapacaensis would run to L. infraspinosa in recent taxonomic keys. The fact that both L. georgii and L. tarapacaensis are locally sympatric with L. infraspinosa helps to clarify the taxonomic limits of the latter species. New keys to the subgenus Evandromyia are provided.     

On the cuticular structure of Araucaria (Araucarites) cutchensis (Feistmantel) comb. nov. from the Jabalpur series, India

The cuticular structure of seed scales referable to Araucaria cutchensis Feistmantel is described and compared with that of seed scales of modern Araucaria columnaris (Forster) Hooker. Since no significant differences were noticeable between the external form or cuticular structure of the fossil and living scales, Araucarites cutchensis Feistmantel has been renamed Araucaria cutchensis (Feistmantel) comb. nov.     

A revision of Centella series Capenses (Apiaceae)

Centella capensis (L.) Domin and related species form a distinct but poorly known group within the genus. The most conspicuous diagnostic feature is the unique inflorescence structure. Each umbel comprises a central umbellule reduced to a single, sessile, functionally female flower and four lateral, functionally male, pedicellate umbellules each reduced to a single flower. The umbel is surrounded by four large, foliaceous bracts. Another unusual character is the habit. Most of the species are annuals or short-lived perennials, while all other species of the genus are perennial shrublets. A taxonomic revision of the four species and three varieties recognized, is presented.     

Three new species of Centella series Glabratae (Apiaceae)

Three new species of Centella series Glabratae are described in this paper: C. brachycarpa, C. dolichocarpa and C. pilosa. These species are similar to C. difformis , and in order to clarify species limits the latter is also described and illustrated. The fruit shape and the bulging commissure of the new species show that the sectional limits of the series Glabratae will have to be revised to include C. difformis and related species, previously associated with the series Montanae.     

A double (series) pump model for transporting epithelia

This paper considers the behaviour of an epithelial structure in which the opposite faces of the tissue are able to actively transport sodium ions in the same direction, thus affecting a net transfer of sodium across the tissue. The short circuit current of an electrical equivalent circuit under steady-state and transient conditions is considered. This latter condition represents the behaviour of an epithelium when sodium is removed from the side from which it is transported. The behaviour of the electrical model is compared to that of actual epithelia under experimental conditions.     

Relative efficiencies of a series of square-planar plantinum(II) compounds on Salmonella mutagenesis.

Twelve Pt(II) compounds have been tested for mutagenicity on Salmonella typhimurium (strain TA 100). Very high mutagenic activities were found for the cis derivatives. A correlation is suggested between these results and a formerly described model of chemical reactivity towards DNA, according to which cis derivatives from intra-strand chelates with guanine. A smaller activity was found with monodentate complexes with DNA.     

Additional Ecuadorian species in Calathea series Comosae (Marantaceae)

Three new species in Calathea series Comosae (Petersen) Schumann are described from Ecuador: Calathea pallidicosta, C. attenuata and C. lagoagriana. Calathea pallidicosta is currently known only from Ecuador, C. lagoagriana occurs in both Colombia and Ecuador while C. attenuata is more widespread, occurring in Colombia, Ecuador, Perú and Brasil. Calathea attenuata and C. pallidicosta are in the monomorphic-bracted group of C. series Comosae while C. lagoagriana is in the dimorphic-bracted group. Calathea lagoagriana possibly hybridizes with C. loeseneri Macbride.     

omega-(Imidazol-4-yl)alkane-1-sulfonamides: a new series of potent histamine H(3) receptor antagonists.

omega-(1H-Imidazol-4-yl)alkane-1-sulfonamides were prepared and found to be potent histamine H(3) receptor antagonists. High receptor affinity and a low difference in the data between the bioassays were achieved with 5-(1H-imidazol-4-yl)pentane-1-sulfonic acid 4-chlorobenzylamide (16). Good in vitro profiles were also obtained for 2-hydroxysulfonamide and vinylsulfonamide analogues. This complements and completes the existing set of imidazole-based sulfonamides and sulfamides.