Dietary polyamines promote the growth of azoxymethane-induced aberrant crypt foci in rat colon

We have examined whether dietary polyamines influence the formation and initial growth of azoxymethane (AOM)-induced aberrant crypt foci (ACF) in rat colon. Effects of a combination of dietary polyamines at three dose levels (putrescine: 50, 280, 740 nmol/g; spermidine: 10, 261, 763 nmol/g; spermine: 1, 31, 91 nmol/g) in the polyamine-poor AIN-76A diet were studied in animals in two different experimental situations: animals treated with AOM alone and animals treated with AOM + difluoromethylornithine (DFMO), a specific inhibitor of endogenous polyamine synthesis. In both experimental situations, dietary polyamines enhanced the growth of ACF, expressed as the number of large ACF (foci with three or more aberrant crypts, ACF > or = 3), whereas the formation of ACF, expressed as the number of ACF, was apparently not altered. In animals treated with AOM alone, maximal growth enhancing effect on ACF was nearly obtained with the median level of dietary polyamine. In rats fed a low polyamine diet, basic AIN-76A, DFMO reduced the growth of AOM-induced ACF by 83%. This inhibitory effect of DFMO was counteracted by dietary polyamines in a dose- dependent manner, and it was abolished at the highest level of polyamines. In conclusion, it was demonstrated that dietary polyamines are able to enhance the growth of AOM-induced ACF. Further, dietary polyamines reversed the DFMO-caused inhibition of ACF growth, probably by compensating for the DFMO-reduced endogenous polyamine synthesis.      

Evasin‐3‐like anti‐chemokine activity in salivary gland extracts of ixodid ticks during blood‐feeding: a new target for tick control

Ticks exploit many evasion mechanisms to circumvent the immune control of their hosts including subversion of the communication language between cells of the immune system provided by chemokines and other cytokines. One subversive molecule secreted in the saliva of Rhipicephalus sanguineus is Evasin‐3, a structurally unique 7 kDa protein that selectively binds the neutrophil chemoattractants, CXCL8 and (with lower affinity) CXCL1. We compared anti‐human CXCL8 and anti‐mouse CXCL1/KC activities in salivary gland extracts prepared from adult Amblyomma variegatum, Rhipicephalus appendiculatus and Dermacentor reticulatus ticks during blood‐feeding. Both anti‐CXCL8 activity and anti‐CXCL1 activity were detected in all species and in both adult females and males, with consistently higher activity levels against CXCL8. These results suggest that Evasin‐3‐like activity is common amongst metastriate ixodid tick species, and provide further evidence of the importance to ticks in controlling neutrophils during blood‐feeding. As such, Evasin‐3 offers a new target for anti‐tick vaccine development.     

β地贫CD41-42突变杂合子复合缺失型α地贫双重杂合子的基因检测与血液学分析

目的了解β地中海贫血(地贫)CD41-42(-TCTT)杂合子(β41-42杂合子)复合缺失型α地贫双重杂合子在本地区β41-42杂合子个体中的检出情况及其临床血液学表现.方法分别采用单管多重PCR与反向点杂交法检测缺失型α地贫与β地贫基因,常规进行血细胞分析及其它地贫筛查试验.结果 144例β41-42杂合子有8例同时复合缺失型α地贫杂合子,其中7例(4.9%)携带有α地贫1基因(αα/--SEA),1例(0.69%)携带有缺失型HbH基因(-α3.7/--SEA).7例复合α地贫1患者的MCV均都高于另外136例单纯的β41-42杂合子的MCV平均值(63.53fl); 而对携带有HbH基因的样本进行pH8.6与6.5的血红蛋白电泳时都无法找到HbH区带.结论诊断β41-42杂合子复合α地贫双重杂合子的患者时,如只依赖其临床表现和常规的实验室检查结果作为筛查诊断的指标,容易会出现有病患的α或β地贫基因漏诊的情况.     

SOFFCO, Montpellier 31 mai–2 juin 2012

Index

SOFFCO, Montpellier 31 mai–2 juin 2012 Index des auteurs     

Cation-osmotic Haemolysis in Patients with Retinal Vein Occlusion

The purpose of this work was to use a new technique to assess erythrocyte deformability in patients with retinal vein occlusion. Erythrocyte microrheology changes were measured by cation-osmotic haemolysis (COH) in healthy donors and in patients with both central (n= 6) and branch (n= 16) retinal vein occlusion up to 12 months after the occlusion. The patient group consisted of five patients with ischaemic and 17 with oedematous vein occlusion. The control group consisted of the same number of age-, sex- and risk factor (hypertension)-matched donors. In patients with retinal vein occlusion, COH was significantly decreased compared to the control group. The decrease was most marked at low and high concentrations of incubating media where the differences reached high statistical significance (p<0.01–0.001). In our previous experiments we showed that COH and erythrocyte deformability (ED) are closely related and that COH reflects basic information about erythrocyte deformability. Thus, decreased COH in patients with retinal vein occlusion points to reduced ED in comparison with the control group. We, therefore, assume that impairment in ED together with other microrheological abnormalities contributes to the pathophysiology of changes in patients with retinal vein occlusion.     

Sequence Similarities and Evolutionary Relationships of Influenza Virus A Hemagglutinins

This study brings the analysis of amino acid sequences of hemagglutinin (HA) from the influenza virus A that can infect a wide variety of birds and mammals. 191 sequences belonging to all known 15 HA subtypes were compared. The emphasis was given on functional sites (receptor-binding cavity with its right and left edges) and degree of their conservation in each subtype. Three evolutionary trees of 15 avian HA representatives were constructed: one tree based on the alignment of the entire HA sequences and two trees based on the alignment of HA1 and HA2 chains, respectively. The results have shown that, despite low degree of sequence similarity among the 191 sequences of HA1 subunit, the active site is well conserved, and that there are only marginal differences in the clustering of the individual HA subtypes between the two subunit trees. In this respect, the subtype H9 seems to be the most fluctuating example. The proposals of the probable avian HAs that could be the closest relatives to human (mammalian) HAs were also provided for several HA subtypes.