Corticosteroid Therapy in Acute and Subacute Arachnoiditis - A Case Series.

Arachnoiditis is difficult to treat. Patients are often left frustrated after many failed trials of conservative therapies without symptom resolution. Surgery may provide symptom relief for a short period of time, but their pain often returned. Herein, we present three cases of acute arachnoiditis following three different pain procedures: epidural blood patch, IDDS implant, and epidural steroid injection. The patients were diagnosed and treated with corticosteroids within 10 days of the procedure. Two patients were treated with the same oral steroid regiment, while the third patient was treated with both oral and IV steroid. All three patients had good outcomes at the completion of their steroid therapy. This case series may provide insight into treating acute and subacute arachnoiditis from pain interventions.

Aerodynamics of saccate pollen and its implications for wind pollination.

Pollen grains of many wind-pollinated plants contain 1-3 air-filled bladders, or sacci. Sacci are thought to help orient the pollen grain in the pollination droplet. Sacci also increase surface area of the pollen grain, yet add minimal mass, thereby increasing dispersal distance; however, this aerodynamic hypothesis has not been tested in a published study. Using scanning electron and transmission electron microscopy, mathematical modeling, and the saccate pollen of three extant conifers with structurally different pollen grains (Pinus, Falcatifolium, Dacrydium), we developed a computational model to investigate pollen flight. The model calculates terminal settling velocity based on structural characters of the pollen grain, including lengths, widths, and depths of the main body and sacci; angle of saccus rotation; and thicknesses of the saccus wall, endoreticulations, intine, and exine. The settling speeds predicted by the model were empirically validated by stroboscopic photography. This study is the first to quantitatively demonstrate the adaptive significance of sacci for the aerodynamics of wind pollination. Modeling pollen both with and without sacci indicated that sacci can reduce pollen settling speeds, thereby increasing dispersal distance, with the exception of pollen grains having robust endoreticulations and those with thick saccus walls. Furthermore, because the mathematical model is based on structural characters and error propagation methods show that the model yields valid results when sample sizes are small, the flight dynamics of fossil pollen can be investigated. Several fossils were studied, including bisaccate (Pinus, Pteruchus, Caytonanthus), monosaccate (Gothania), and nonsaccate (Monoletes) pollen types.