How does measurement of platelet P-selectin compare with other methods of measuring platelet function as a means of determining the effectiveness of antiplatelet therapy?

Measurement of P-selectin on activated platelets as a means of measuring platelet function utilizing the technology described here has the advantage of not requiring immediate access to specialist equipment and expertise. Blood samples are activated, fixed, stored, and transported to a central laboratory for flow cytometric analysis. Here we have compared P-selectin with other more traditional approaches to measuring platelet function in blood and/or platelet-rich plasma (PRP) from patients with acute coronary syndromes on treatment for at least 1 month with either aspirin and clopidogrel or aspirin with prasugrel. The comparators were light transmission aggregometry (LTA), VerifyNow and Multiplate aggregometry (for determining the effects of aspirin) and LTA, VerifyNow and Multiplate together with the BioCytex VASP phosphorylation assay (for the P2Y₁₂ antagonists). The P-selectin Aspirin Test revealed substantial inhibition of platelet function in all but three of 96 patients receiving aspirin with clopidogrel and in none of 51 patients receiving aspirin and prasugrel. The results were very similar to those obtained using LTA. There was only one patient with high residual platelet aggregation and low P-selectin expression. The same patients identified as “non-responders” to aspirin also presented with the highest residual platelet activity as measured using the VerifyNow system, although not quite as well separated from the other values. With the Multiplate test only one of these patients clearly stood out from the others. The results obtained using the P-selectin P2Y₁₂ Test in 102 patients taking aspirin and clopidogrel were similar to the more traditional approaches in that a wide scatter of results was obtained. Generally, high values seen with the P-selectin P2Y₁₂ Test were also high with the LTA, VerifyNow, Multiplate, and BioCytex VASP P2Y₁₂ Tests. Similarly, low residual platelet function using the P2Y₁₂ test was seen irrespective of the testing procedure used. However, there were differences in some patients. Prasugrel was always more effective than clopidogrel in inhibiting platelet function with none of 56 patients (P-selectin and VerifyNow), only 2 of 56 patients (Multiplate) and only 3 of 56 patients (Biocytex VASP) demonstrating high on-treatment residual platelet reactivity (HRPR) defined using previously published cut-off values. The exception was LTA where there were 11 of 56 patients with HRPR. It remains to be seen which experimental approach provides the most useful information regarding outcomes after adjusting therapies in treated patients.     

Dexamethasone 8 mg in combination with ondansetron 4 mg appears to be the optimal dose for the prevention of nausea and vomiting after laparoscopic cholecystectomy

PURPOSE: The combination of antiemetic drugs could be a solution to prevent severe postoperative nausea and vomiting (PONV). The aim of this randomized double blind, dose-ranging study was to determine the minimum single effective dose of dexamethasone combined with ondansetron for the prevention of PONV in patients undergoing laparoscopic cholecystectomy. METHODS: One hundred eighty patients were allocated randomly to one of six groups to receive saline (P group), ondansetron 4 mg (O group), or ondansetron 4 mg and dexamethasone at doses of 2 mg (OD2 group), 4 mg (OD4 group), 8 mg (OD8 group), and 16 mg (OD16 group). A standardized general anesthetic was used. All episodes of PONV during the intervals of zero to six hours, 6-12 hr and 12-24 hr after surgery were evaluated using a numeric scoring system. Mean visual analogue scale pain scores at rest and on movement, the time to first demand of analgesia, total analgesic consumption in 12 hr epochs, duration of hospital stay, and side effects were recorded. RESULTS: The incidence of PONV in the OD8 (16%) and OD16 (16%) groups was lower than in the 83% (P < 0.001) and O groups (50%) at the 12-24 hr epoch (P < 0.05). There were no differences in antiemetic effect between the O, OD2 and OD4 groups and between the OD8 and OD16 groups. Pain scores, total analgesic consumption, duration of hospital stay and side effects were similar among groups. CONCLUSION: Our results suggest that 8 mg is the minimum dose of dexamethasone that, combined with ondansetron 4 mg will effectively prevent PONV in patients undergoing laparoscopic cholecystectomy.     

Benign osteoblastoma of the parietal bone

A 5-year-old girl presented with a 1-year history of a subcutaneous swelling in the right parietal region. There were no cerebral symptoms or signs. Plain X-ray of the skull showed a lytic bony lesion with sclerotic margin. Computed tomography showed a hypodense, osteolytic lesion with thinned and bulged inner and outer skull tables with intact continuity. There was no intracranial lesion. At operation, the mass was found to be pink and granular, and was totally enucleated. Histology revealed it to be a benign osteoblastoma.