Upregulation of Fas and FasL expression in nicotine-induced apoptosis of endothelial cells.

Although smoking-related coronary vascular disease is well documented, the effects of nicotine have not been fully investigated. There is controversy over reports about the effect of nicotine on apoptosis. The effect of nicotine on apoptosis of human umbilical vein endothelial cells (HUVECs) and the expressions of Fas/Fas ligand (FasL) and caspase-3 were evaluated in this study. Annexin V fluorescein isothiocyanate and propidium iodide double staining demonstrated that nicotine (0.2 microM, 0.5 microM and 1 microM) could induce apoptosis of HUVECs; reverse transcription (RT)-PCR and Western blotting analysis demonstrated that levels of Fas and FasL expression were increased in nicotine-treated HUVECs. Moreover, caspase-3 expression was also increased. These data indicate that nicotine induces the apoptosis of HUVECs, and that the Fas/FasL pathway may play an important role. This provides evidence that nicotine may have an important role in cardiovascular pathology and atherogenesis.

[Analysis of Leishmania species and strains from China by RAPD technique].

OBJECTIVE: To analyze genetic relationship of Leishmania species and strains from China by RAPD technique. METHODS: DNAs from Leishmania strains, including L. donovani (L. d.) isolates from patients, dogs and sandflies of three different foci in China and international reference strains, were amplified by seven random primers. The DNA polymorphic bands detected were analyzed by clustering analysis with SPSS software. RESULTS: 1. L. d. isolates from hill and plain foci in China were divided into two groups. The genetic distance of L. d. isolates is distant between them. 2. L. d. XJ771, L. d. XJ901, L. d. XJ801 from desert, vicinity of desert, and plain regions in Xinjiang were in the same group. It indicated that the genetic distance among L. d. isolates from the three regions is close. 3. L. d. isolated from VL patients and dogs in hill foci could not be discriminated distintly, showing high homology between them. 4. L. d. DD8 from India, the reference strain of plain type, was clustered with L. d. isolates from plain foci in China. It provided scientific basis for the viewpoint "Kala Azar from east area of China is similar to that from India". 5. L. infantum and L. d. isolates from hill foci in China were clustered into different groups. 6. The genetic distance is close between L. d. isolates from plain foci in China and L. d. Jed; 7. L. infantum and L. tropica showed the closest genetic distance. CONCLUSION: Differences at genetic level exist in Leishmania isolates from different foci in China.

Beta-amyloid peptide fragment 31-35 induces apoptosis in cultured cortical neurons.

A synthetic fragment 31-35 of beta-amyloid peptide was used in cultured cortical neurons to examine whether this smaller sequence could trigger apoptotic degeneration in vitro by using morphological, biochemical and flow-cytometric examinations. The results showed that: (i) neurons treated with fragment 31-35 of beta-amyloid peptide exhibited membrane blebbing, compaction of nuclear chromatin, nuclear shrinkage and nuclear fragmentation; (ii) a typical DNA ladder was revealed by agarose gel electrophoresis following fragment 31-35 of beta-amyloid peptide exposure; (iii) the internucleosome DNA fragmentation was also detected by flow-cytometric examination following fragment 31-35 of beta-amyloid peptide exposure; and (iv) the DNA fragmentation induced by fragment 31-35 of beta-amyloid peptide in the above two examinations could be blocked by co-treatment with aurintricarboxylic acid or actinomycin D. It is suggested that fragment 31-35 of the beta-amyloid peptide may be a shorter sequence of beta-amyloid peptide responsible for triggering an apoptotic process in cultured neurons.