Excessive apoptosis is implicated in the pathogenesis of myelodysplastic syndromes (MDS). We assessed by flow cytometry the expression of several members of the Bcl‐2 family in bone marrow mononuclear cells (BMMNC) of 168 MDS samples at diagnosis. The proteins studied were Bcl‐2, Bcl‐xL (anti‐apoptotic), Bax, Bad, Bak, and Bcl‐xS (pro‐apoptotic). The percentage of BMMNC expressing Bcl‐2 and Bcl‐xL was higher in refractory anemia with excess of blasts (RAEB), RAEB in transformation (RAEB‐T), and chronic myelomonocytic leukemia (CMML) than in refractory anemia (RA) and RA with ringed sideroblasts (RAS). Conversely pro‐apoptotic proteins Bad, Bak, and Bcl‐xS were detected in a higher percentage of cells in RA and RAS. RA and RAS were associated with an increased Bcl‐xS/Bcl‐xL ratio. The expression of anti‐apoptotic proteins was also correlated with that of CD34 and P170 and with the percentage of blast cells. Two‐color analyses demonstrated that CD34 and Bcl‐2 were usually expressed in the same cells. No significant correlation was found with cytogenetic abnormalities. Higher expression of pro‐apoptotic Bcl‐2‐family proteins (Bak, Bad, Bcl‐xS) and higher Bcl‐xS/Bcl‐xL ratio were associated with longer survival and decreased risk of leukemic transformation in univariate analysis, whereas expression of anti‐apoptotic proteins was associated with decreased survival. Consequently Bcl‐2 proteins expression was well correlated with the International Prognostic Scoring System (IPSS). Our data confirm that the control of apoptosis is deregulated in MDS cells. Moreover, the study of markers such as CD34 (or Bcl‐2), Bcl‐xL, and Bcl‐xS provides additional prognostic information. Am. J. Hematol. 70:115–125, 2002.

The real impact of nanoparticles on male fertility is evaluated after a careful analysis of the available literature. The first part reviews animal models to understand the testicular biodistribution and biopersistence of nanoparticles, while the second part evaluates their in vitro and in vivo biotoxicity. Our main findings suggest that nanoparticles are generally able to reach the testicle in small quantities where they persist for several months, regardless of the route of exposure. However, there is not enough evidence that they can cross the blood–testis barrier. Of note, the majority of nanoparticles have low direct toxicity to the testis, but there are indications that some might act as endocrine disruptors. Overall, the impact on spermatogenesis in adults is generally weak and reversible, but exceptions exist and merit increased attention. Finally, we comment on several methodological or analytical biases which have led some studies to exaggerate the reprotoxicity of nanoparticles. In the future, rigorous clinical studies in tandem with mechanistic studies are needed to elucidate the real risk posed by nanoparticles on male fertility.

Conventional nanotoxicological assays are subjected to various interferences with nanoparticles and especially carbon nanotubes. A multiparametric flow cytometry (FCM) methodology was developed here as an alternative to quantify oxidative stress, mitochondrial impairment, and later cytotoxic and genotoxic events. The experiments were conducted on RAW264.7 macrophages, exposed for 90 min or 24 h-exposure with three types of multiwalled carbon nanotubes (MWCNTs): pristine (Nanocyl™ CNT), acid functionalized (CNTf), or annealed treatment (CNTa). An original combination of reactive oxygen species (ROS) probes allowed the simultaneous quantifications of broad-spectrum ROS, superoxide anion (O₂^•−), and hydroxyl radical (•OH). All MWCNTs types induced a slight increase of broad ROS levels regardless of earlier antioxidant catalase activity. CNTf strongly stimulated the O₂^•− production. The •OH production was downregulated for all MWCNTs due to their scavenging capacity. The latter was quantified in a cell-free system by electron paramagnetic resonance spectroscopy (EPR). Further FCM-based assessment revealed early biological damages with a mitochondrial membrane potential collapse, followed by late cytotoxicity with chromatin decondensation. The combined evaluation by FCM analysis and cell-free techniques led to a better understanding of the impacts of MWCNTs surface treatments on the oxidative stress and related biological response.