In vivo cellular tropism of human T-cell leukemia virus type 1.

To establish the phenotype of human T-cell leukemia virus type 1 (HTLV-1)-infected cells in peripheral blood, the polymerase chain reaction was used to detect and quantitate viral DNA in subpopulations of leukocytes obtained from patients with tropical spastic paraparesis and asymptomatic carriers. HTLV-1 could not be detected in peripheral blood mononuclear cells thoroughly depleted of T lymphocytes (E- CD3-), nor could it be detected in highly enriched populations of B lymphocytes (E- CD19+), monocytes (E- CD14+), or natural killer cells (E- CD16+). T lymphocytes were strongly positive for HTLV-1, and fractionation of this population revealed that 90 to 99% of the HTLV-1 DNA segregated with the CD4+ CD8- and CD45RO+ subsets. No difference between the cell type distribution of HTLV-1 in the asymptomatic carrier and the subjects with tropical spastic paraparesis was evident. Southern hybridization of genomic DNA prepared from the peripheral blood of HTLV-1 carriers indicated that up to 10% of circulating leukocytes may carry the HTLV-1 provirus.     

The Influences of Epicuticular Wax Disruption and Cutinase Resistance on Penetration of Tomatoes by Colletotrichum gloeosporioides

Conidia of Colletotrichum gloeosporioides germinated on green and ripe tomato fruit with intact epicuticular wax, and formed penetration pegs below melanized appressoria. If the delicate layer of epicuticular wax was distupted by abrasion or removed by solvents before inoculation, apparent increased diffusion of fruit substances into the inoculum stimulated fungal growth, hyphal anastomosis and the production of penetration pegs from hyaline appressoria. This was followed by cutlcle erosion centred on the penetration pegs in green fruit allowing sec-ondary growth of infection hyphae. Due to the development of cutinase resistance when the cuticle became yellow at ripening, no cuticle erosion occurred at penetrations on ripe fruit Since cuticle erosion followed penetration of the cutinase-susceptible cuticle and since penetration peg formation was not hindered by the cutinase cuticle, the process of primary penetration is regarded as mechanical.     

Once-daily dosing with Atenolol in patients with mild or moderate hypertension.

Because of the difficulties patients have in adhering to their drug regimens a trial was performed in which patients with essential hypertension were given, in random order and for four weeks each, three different doses of atenolol to be taken once daily. Atenolol effectively decreased lying and standing blood pressures, and there was no difference between the effects of the three doses. The simplicity of the regimen, as well as atenolol''s freedom from troublesome side effects, should be valuable in helping patients adhere to long-term treatment.