Olfactory bulb plasticity ensures proper olfaction after severe impairment in postnatal neurogenesis.

The olfactory bulb (OB) neurons establish a complex network that ensures the correct processing of the olfactory inputs. Moreover, the OB presents a lifelong addition of new neurons into its existing circuitry. This neurogenesis is considered essential for the OB function. However, its functional impact on physiology and behavior is still unclear. Here, we investigate the mechanisms of OB plasticity that underlie bulbar physiology in relation to severe damage of neurogenesis. The neurogenesis of young mice was altered by ionizing radiation. Afterwards, both multi-channel olfactometry and electrophysiological studies were performed. Furthermore, neurogenesis and differentiation of the newly formed cells were assessed using bromodeoxyuridine labeling combined with a wide battery of neuronal markers. Our results demonstrate a reduction in both neurogenesis and volume of the OB in irradiated animals. The number of neuroblasts reaching the OB was reduced and their differentiation rate into interneurons selectively changed; some populations were noticeably affected whereas others remained preserved. Surprisingly, both olfactory detection and discrimination as well as electrophysiology presented almost no alterations in irradiated mice. Our findings suggest that after damaging postnatal neurogenesis, the neurochemical fate of some interneurons changes within a new biological scenario, while maintaining homeostasis and olfaction.

Evaluation of a CD61 MoAb method for enumeration of platelets in thrombocytopenic patients and its impact on the transfusion decision-making process.

BACKGROUND: Almost all automated hematology cell analyzers use methods based on either the impedance (PLTi) or the optical (PLTo) properties of the cells for performing platelet counts. To improve the accuracy of platelet counts in peripheral blood (PB), the use of CD61 (GPIIIa) MoAbs (ImmunoPLT method) has recently been introduced in an automated hematology blood-analyzer system (Cell-Dyn 4000, Abbott Diagnostics). STUDY DESIGN AND METHODS: A comparative evaluation was made of the accuracy and precision of the three methods currently available in the Cell-Dyn 4000 automated hematology cell analyzer for counting the number of platelets per microliter of PB in a total of 47 patients with chemotherapy-induced thrombocytopenia. A flow cytometric PB platelet count was also performed in parallel and used as an external reference. RESULTS: PB platelet counts showed a good correlation among the PLTo, CD61-ImmunoPLT, and flow cytometric methods. In contrast, the PLTi procedure usually provided an overestimation of the number of platelets per microliter. Although a good correlation was observed between the flow cytometric reference method and both the ImmunoPLT and PLTo methods, the highest degree of agreement was found for the ImmunoPLT techniques (94% vs. 67%). A comparative analysis of the PLTo and CD61-ImmunoPLT methods with regard to their value for predicting platelet transfusion needs on the basis of specific flow cytometric platelet count thresholds showed a good correlation when the cutoff level of 10,000 platelets per microL was used. In contrast, at the threshold of 20,000 platelets per microL, slight differences were observed between the PLTo and CD61-ImmunoPLT procedures for predicting transfusion needs. CONCLUSION: Such results indicate that, if the CD61-ImmunoPLT method is used in the platelet transfusion decision-making process, unnecessary platelet transfusions could be avoided in up to 17.5 percent of persons with a PLTo count of <20,000 platelets per microL.