Impact of pyrethroid-impregnated curtains on Phlebotomus papatasi sandflies indoors at Khartoum, Sudan

Laboratory and field investigations were made in an endemic focus of cutaneous leishmaniasis in Khartoum State, Sudan, to evaluate the effects of permethrin-impregnated curtains on the human-biting activity, nocturnal activity and resting behaviour of the vector sandfly Phlebotomus papatasi (Diptera: Psychodidae) indoors. Laboratory bioassays showed that curtains impregnated with 0.5, 1.0 or 1.5 g/m2 permethrin all gave 100% mortality within 24h of exposure of P. papatasi for 3 min. Under natural field conditions, the biting activity indoors and the resting density of P. papatasi were significantly reduced (P<0.001 and P=0.036, respectively) in rooms provided with permethrin-impregnated curtains as compared to control rooms left without curtains or fitted with unimpregnated curtains. No significant difference was found between the numbers of nocturnally active P. papatasi collected in rooms provided with impregnated curtains and rooms left without curtains or provided with unimpregnated curtains (P=0.377). Evidently P. papatasi was not repelled by these doses of permethrin on curtains, but the survival rate of sandflies collected from test rooms provided with permethrin-impregnated curtains was significantly reduced (P=0.036). We conclude that use of permethrin-impregnated curtains may provide a good control method for P. papatasi and other endophilic and/or endophagic sandfly vectors of leishmaniasis.     

Modification of ornithine decarboxylase activity by adrenergic stimulation in cultured chicken spleen cells

1. In vivo, adrenergic agonists promote an increase of ornithine decarboxylase activity (ODC) in chicken spleen, as opposed to a decrease in thymus and bursa of Fabricius. The increase is not due to the cell fraction separated on Lymphoprep, i.e. the spleen cells, but it could be due to the macrophages. 2. With spleen cells in culture, a marked increase of ODC activity is observed during the first 3 hr, followed by a decrease. 3. cAMP drastically decreases after 10 min in culture. 4. Adrenergic agonists promote a decrease of activity, both alpha and beta receptors being involved in these modifications. TPA promotes partial desensitization. 5. Selenite, which in vivo has the same effect as epinephrine, enhances ODC activity in culture. Propranolol partially counteracts this effect, while prazosin has a synergistic effect. TPA partially desensitizes spleen cells to selenite.     

Changes in receptor status after treatment with tamoxifen in endometrial cancer

Estrogen (ER) and progesterone receptor (PgR) status was determined in 41 women with operable endometrial cancer before and after administration of tamoxifen (TAM). The first sample was obtained by hysteroscopy to ensure a precise biopsy of neoplastic tissue; the second was done on the surgical specimen. PgR content was significantly increased after TAM treatment and this data was compared with the degree of tumor differentiation.     

Ultrastructural and immunocytochemical evidences of core-particle formation in the methylotrophic Pichia pastoris yeast when expressing HCV structural proteins (core-E1).

Particulate antigens of the Hepatitis C virus (HCV) are reported for the first time by transmission electron microscopy in Pichia pastoris. The yeast was cloned to express the first 339 NH2-terminal amino acids of the HCV polyprotein (C-E1.339 polypeptide). The C-E1.339 polypeptide covers the putative 191 aa of the core protein (aa 1-191) and 148 aa of the E1 envelope antigen (aa 192-339). Virus-like particles (VLP) with diameters ranging from 20 nm to 30 nm were specifically observed in those cells expressing the HCV polyprotein. The VLP appeared along the membrane of the endoplasmic reticulum, but were fundamentally localized in vacuoles, either free or inside autophagic bodies. Clustered particles, chains of particles, high-density reticular structures, and crystalloid bodies were also detected, the last one being an orderly arrangement of particles with 20 nm diameters. The crystal-associated particles are well differentiated from the intracellular VLP because of their uniform size and shape. We argue that membrane components are retained in the architecture of the VLP, conferring to this particle certain heterogeneity. Both kinds of particles, the VLP formed after treatment with NP-40 and the crystal-associated particles, were core protein-positives. Whether they reflect mature HCV nucleocapsid or intermediary states in the viral nucleocapsid morphogenesis remains unknown. We conclude that, like mammalian cell lines, the P. pastoris yeast could be an appropriate host for the analysis of HCV polyprotein processing and, eventually, virus assembly.