Why Self-Induced Pain Feels Less Painful than Externally Generated Pain: Distinct Brain Activation Patterns in Self- and Externally Generated Pain

Voluntary movement generally inhibits sensory systems. However, it is not clear how such movement influences pain. In the present study, subjects actively or passively experienced mechanical pain or pressure during functional MRI scanning. Pain and pressure were induced using two modified grip strengthener rings, each twined with four crystal bead strings, with polyhedral beads to induce pain, or spherical beads to induce pressure. Subjects held one ring in the left hand and were either asked to squeeze their left hand with their right hand (i.e., active pain or pressure), or to have their left hand squeezed by the experimenter (i.e., passive pain or pressure). Subjects rated the intensity and unpleasantness of the pain sensation lower in the active procedure than in the passive one. Correspondingly, pain-related brain areas were inhibited in the case of self-generated pain, including the primary somatosensory cortex (SI), anterior cingulate cortex (ACC), and the thalamus. These results suggest that active movement behaviorally inhibits concomitant mechanical pain, accompanied by an inhibition of pain response in pain-related brain areas such as the SI cortex. This might be part of the mechanisms underlying the kinesitherapy for pain treatment

The Origin of Intraspecific Variation of Virulence in an Eukaryotic Immune Suppressive Parasite

Occurrence of intraspecific variation in parasite virulence, a prerequisite for coevolution of hosts and parasites, has largely been reported. However, surprisingly little is known of the molecular bases of this variation in eukaryotic parasites, with the exception of the antigenic variation used by immune-evading parasites of mammals. The present work aims to address this question in immune suppressive eukaryotic parasites. In Leptopilina boulardi, a parasitic wasp of Drosophila melanogaster, well-defined virulent and avirulent strains have been characterized. The success of virulent females is due to a major immune suppressive factor, LbGAP, a RacGAP protein present in the venom and injected into the host at oviposition. Here, we show that an homologous protein, named LbGAPy, is present in the venom of the avirulent strain. We then question whether the difference in virulence between strains originates from qualitative or quantitative differences in LbGAP and LbGAPy proteins. Results show that the recombinant LbGAPy protein has an in vitro GAP activity equivalent to that of recombinant LbGAP and similarly targets Drosophila Rac1 and Rac2 GTPases. In contrast, a much higher level of both mRNA and protein is found in venom-producing tissues of virulent parasitoids. The F1 offspring between virulent and avirulent strains show an intermediate level of LbGAP in their venom but a full success of parasitism. Interestingly, they express almost exclusively the virulent LbGAP allele in venom-producing tissues. Altogether, our results demonstrate that the major virulence factor in the wasp L. boulardi differs only quantitatively between virulent and avirulent strains, and suggest the existence of a threshold effect of this molecule on parasitoid virulence. We propose that regulation of gene expression might be a major mechanism at the origin of intraspecific variation of virulence in immune suppressive eukaryotic parasites. Understanding this variation would improve our knowledge of the mechanisms of transcriptional evolution currently under active investigation

Residual Disease in B-Cell Chronic Lymphocytic-Leukemia Patients and Prognostic Value

Twenty-two B-cell chronic lymphocytic leukemia (CLL) patients were investigated to evaluate residual disease in clinico-hematological remission. Residual disease was determined by monotypy of surface light chain expression and by dual-color staining with CD5 and CD19 markers. Samples were analyzed on flow cytometer. Total CD19+ cells above 25%, the CD5+CD19+/total CD19+ cells ratio above 0.25, clonal excess above 0.4 were considered positive for residual disease. According to these immunological criteria, only four cases achieved phenotypic remission. Our data confirm that dual marker analysis is more sensitive than clonal excess and may predict an early relapse. Ig gene rearrangements were studied by Southern blot analysis using IGHJ and IGKC probes in fifteen cases. All 12 cases that retained a detectable rearrangement displayed a phenotypic residual disease. Conversely, in two cases, DNA analysis failed to detect the residual disease characterized by flow cytometry. In conclusion, this study suggests that in B-CLL, dual marker analysis is sensitive in predicting an early relapse in sequential evaluations of residual disease, whereas rearranged bands are undetectable when the proportion of malignant cells is low

Residual Disease in B-Cell Chronic Lymphocytic-Leukemia Patients and Prognostic Value

Twenty-two B-cell chronic lymphocytic leukemia (CLL) patients were investigated to evaluate residual disease in clinico-hematological remission. Residual disease was determined by monotypy of surface light chain expression and by dual-color staining with CD5 and CD19 markers. Samples were analyzed on flow cytometer. Total CD19+ cells above 25%, the CD5+CD19+/total CD19+ cells ratio above 0.25, clonal excess above 0.4 were considered positive for residual disease. According to these immunological criteria, only four cases achieved phenotypic remission. Our data confirm that dual marker analysis is more sensitive than clonal excess and may predict an early relapse. Ig gene rearrangements were studied by Southern blot analysis using IGHJ and IGKC probes in fifteen cases. All 12 cases that retained a detectable rearrangement displayed a phenotypic residual disease. Conversely, in two cases, DNA analysis failed to detect the residual disease characterized by flow cytometry. In conclusion, this study suggests that in B-CLL, dual marker analysis is sensitive in predicting an early relapse in sequential evaluations of residual disease, whereas rearranged bands are undetectable when the proportion of malignant cells is low

Residual Disease in B-Cell Chronic Lymphocytic-Leukemia Patients and Prognostic Value

Twenty-two B-cell chronic lymphocytic leukemia (CLL) patients were investigated to evaluate residual disease in clinico-hematological remission. Residual disease was determined by monotypy of surface light chain expression and by dual-color staining with CD5 and CD19 markers. Samples were analyzed on flow cytometer. Total CD19+ cells above 25%, the CD5+CD19+/total CD19+ cells ratio above 0.25, clonal excess above 0.4 were considered positive for residual disease. According to these immunological criteria, only four cases achieved phenotypic remission. Our data confirm that dual marker analysis is more sensitive than clonal excess and may predict an early relapse. Ig gene rearrangements were studied by Southern blot analysis using IGHJ and IGKC probes in fifteen cases. All 12 cases that retained a detectable rearrangement displayed a phenotypic residual disease. Conversely, in two cases, DNA analysis failed to detect the residual disease characterized by flow cytometry. In conclusion, this study suggests that in B-CLL, dual marker analysis is sensitive in predicting an early relapse in sequential evaluations of residual disease, whereas rearranged bands are undetectable when the proportion of malignant cells is low