Cytoplasmic Microtubules and Radial‐Segmented Nuclei (Rieder Cells)

Abstract

The radial segmentation (RS) of nuclei of human lymphocytes and monocytes was inhibited by vinblastine. Sulfhydryl reagents did not inhibit the formation of RS nuclei. The yield of RS nuclei after incubation in heparinized blood is probably due to the temperature during incubation and not to heparin, as evidenced by comparison with blood samples held fluid by defibrination with streptokinase. In the concentration range that potentiates muscle cell contraction caffeine had no significant influence on the formation of RS nuclei. These findings are discussed in relation to the hypothesis that microtubule shrinkage due to their slow decomposition is instrumental in the formation of RS nuclei.

Botryoid nuclei in the peripheral blood of a dog with heatstroke

“…Although botryoid nuclei appear to be radially segmented, from a strict point of view “radial segmentation” is a phenomenon observed in human mononuclear cells cultured or stored with sodium oxalate and in certain human leukemias of mononuclear cells, which were first described by Rieder in 1893 and named “Rieder cells.” Radial segmentation develops during an aberrant mitotic division because of perinuclear contraction of the mitotic spindle, which on light microscopy is seen as bright cytoplasmic areas of “less stainable matter” between the nuclear segments . Although it has been reported that botryoid nuclei result from radial segmentation, cytoplasmic brightening is not present in botryoid cells and, in the authors' opinion, botryoid cells are not undergoing mitosis, but are more likely to have been damaged by high temperature.…”

Hypersegmented Neutrophils in an Adolescent Male With Heatstroke

“…6 In addition, microtubular decomposition may play a role. 7 In vitro experiments have shown that radially segmented neutrophils are induced by applying heat. 8 Botryoid changes in >50% of neutrophils on a peripheral blood smear may be sufficient to diagnose heatstroke.…”