Cytotoxic action of alpha-methylene lactones towards HeLa cells in culture

Possible targets to account for the qtotoxic activity of the a-methylene containing sesquiterpenes elephantopin and vernoleph, and an a-methylene-lactone steroidal derivative, 3-methoxy-16-methylene-17-oxo-17a-D homoestra-1,3,5,(10)-triene, have been studied. The compounds reduced surface and intracellular thiol levels in HeLa S3 ceb, caused an inhibition of Na+/K+-ATPase and an inhibition of the incorporation of [³H]thymidine into macromolecules. In addition, the steroidal compound, but not the sesquiterpene elephantopin, released lysosomal enzymes and caused marked changes in the structural integrity of the cells. Observed effects of α-methylene lactones on cellular respiration and [³H]thymidine uptake were not a consequence of alkylation. The results support the concept of the cell membrane and in particular Na⁺/K⁺-ATPase as a target for sesquiterpene lactone alkylation.     

Quantitation of CD62, soluble CD62, and lysosome-associated membrane proteins 1 and 2 for evaluation of the quality of stored platelet concentrates

BACKGROUND: Platelets become activated during storage, which results in secretion of granules, vesiculation of microparticles, secretion of protein, and a number of other biochemical and morphologic processes that decrease the utility of platelet concentrates stored for transfusion. STUDY DESIGN AND METHODS: To evaluate the quality of stored platelet concentrates, the cell surface expression of specific activation-dependent antigens (CD62 and lysosome-associated membrane proteins 1 and 2 [LAMP-1, LAMP-2]) on platelets stored in a hospital blood bank over a 7-day period was examined. Relative microparticle counts and the expression of CD62 by microparticles, as well as platelet concentrate supernatant levels of soluble CD62, were determined. RESULTS: The percentage of platelets expressing CD62 increased significantly from Day 1 to Day 5 (p < 0.05) of storage; the mean fluorescence values for CD62 did not. In contrast, the mean fluorescence values of LAMP-1 and LAMP-2 rose significantly (p < 0.01 and p < 0.05, respectively) between Days 1 and 5. Significant declines in CD62, LAMP-1, and LAMP-2 percent expression and mean fluorescence were seen on Day 6 of storage (p < 0.001). Microparticle numbers increased significantly during storage and correlated with levels of CD62 protein (free and membrane-bound) (r = 0.95 vs. Day 2, p < 0.05; r = 0.88 vs. Day 5, p < 0.05). CONCLUSION: Flow cytometric evaluations of the expression of cell surface CD62, LAMP-1, and LAMP-2 are complementary tests that, especially when used in conjunction with the quantitation of CD62 protein, provided a simple and effective means of evaluating the quality of platelet concentrates stored for transfusion.     

Antiretroviral agents inhibit infection of human cells by porcine endogenous retroviruses

The efficacy of antiretroviral drugs against porcine endogenous retroviruses (PERV) that may be harbored in pig organs intended for transplantation was examined in human cells in vitro. The nucleoside analogs zidovudine and dideoxyinosine were found to effectively inhibit PERV replication.     

Advanced life support cardiac arrest scenario test evaluation

BACKGROUND: The cardiac arrest scenario test (CASTest) is a central component of the assessment strategy on the Advanced Life Support Course. The aim of this study was to establish equivalence between the four different CASTest scenarios and investigate the impact of profession, candidate order and course centre on the pass rate. MATERIALS AND METHODS: This was a cluster randomised study. CASTest scenarios were randomly allocated to candidates stratified by course centre. Candidate demographics and performance were recorded on the criterion referenced check list along with the final assessment outcome (pass/fail). Differences in pass rates according scenario; profession, course centre and candidate order were examined by Chi-squared and multiple logistic regression. RESULTS: Two thousand, four hundred and forty-nine assessments from 65 course centres were evaluated. There was no difference in pass rate between scenarios (average pass rate 74.4%). Pass rates according to course centre varied widely (40-93%, P<0.0001) as did professional group (42-100%, P<0.0001). The order that candidates took the test did not influence the pass rate. CONCLUSION: The CASTest assessment scenarios used during ALS testing appear equivalent in terms of difficulty. In contrast, the professional background of the candidate and centre at which the assessment is performed do significantly influence the likelihood of passing the assessment. Further evaluation of the reasons for differences between course centres is required.     

Lipopolysaccharide produces dose-dependent reductions of the acoustic startle response without impairing prepulse inhibition in male rats

This study examined the dose-dependent effects of Lipopolysaccharide (LPS) on the acoustic startle response and prepulse inhibition (PPI) in male Long-Evans rats. LPS is known to stimulate the innate immune system and result in behavior modifications referred to as "sickness behaviors". The purpose of this study was to assess the ability of LPS to modulate sensorimotor reflexes (Startle-Only trials) and/or sensory processing (PPI trials). Rats were injected intraperitoneally with LPS (50, 100 or 200 microg/kg LPS, n=9/group) or saline vehicle (n=14) on 2 test days 72 h apart. Subjects were placed in a familiar startle box apparatus where startle response magnitudes were recorded following 115 dB Startle-Only trials and PPI trials (with prepulses at +3, +6 and +12 dB above background noise). Analysis of Startle-Only trials indicated a significant dose-dependent effect of LPS on Test Day 1. The 200 microg/kg LPS group exhibited significantly reduced startle response magnitude relative to all other treatments. On the PPI trials no LPS groups displayed significantly different performance from vehicle controls. Also, DayxDrug interactions for both Startle-Only and PPI trial types indicated behavioral tolerance to LPS. LPS reduced the acoustic startle response in a dose-dependent manner on Test Day 1. From the PPI data, it is evident that all treatment groups elicited near-normal inhibition levels indicating adequate sensory function. In combination, the results suggest that the range of sickness behaviors following LPS-administration to adult rats includes decreased non-voluntary motor activity as reflected by reduced startle magnitude.