The technological imperative in tuberculosis care and prevention in Vietnam

ABSTRACT

A monocausal bacteriological understanding of infectious disease orients tuberculosis control efforts towards antimicrobial interventions. A bias towards technological solutions can leave multistranded public health and social interventions largely neglected. In the context of globalising biomedical approaches to infectious disease control, this ethnography-inspired review article reflects upon the implementation of rapid diagnostic technology in low- and middle-income countries. Fieldwork observations in Vietnam provided a stimulus for a critical review of the global rollout of tuberculosis diagnostic technology. To address local needs in tuberculosis control, health managers in resource-poor settings are readily cooperating with international donors to deploy novel diagnostic technologies throughout national tuberculosis programme facilities. Increasing investment in new diagnostic technologies is predicated on the supposition that these interventions will ameliorate disease outcomes. However, suboptimal treatment control persists even when accurate diagnostic technologies are available, suggesting that promotion of singular technological solutions can distract from addressing systemic change, without which disease susceptibility, propagation of infection, detection gaps, diagnostic delays, and treatment shortfalls persist.     

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.     

Effect of a patellar realignment brace on patellofemoral relationships: Evaluation with kinematic MR imaging

The effect of a newly developed patellar realignment brace was evaluated in 21 patellofemoral joints (19 patients) with patellar subluxation (13 joints with lateral subluxation and eight with medial subluxation) by using active-movement, loaded kinematic magnetic resonance (MR) imaging. Sixteen patellofemoral joints (76%) demonstrated a qualitative correction of or improvement in patellar subluxation (ie, centralization of the patella or a decrease in the displacement of the patella) after application of the brace. Four of the five “failures” occurred in patellofemoral joints that had patella alta and/or dysplastic bone anatomy. These results indicate that the patellar realignment brace was able to counteract patellar subluxation in the majority of patellofemoral joints studied, as shown by active-movement, loaded kinematic MR imaging. This brace appears to be useful for conservative treatment of patients with patellofemoral joint pain secondary to patellar malalignment and maltracking.     

Lesser metatarsophalangeal joint implants

A double-stemmed MTP joint silastic implant has been described that acts as a flexible spacer for a number of pathologic conditions that affect the lesser metatarsophalangeal joints. Preliminary results suggest that this is a feasible alternative to joint destructive procedures with advantages over previously described implants.