Technologies of care and the engineering imaginary: Two approaches to assistive device design for the Global South.

Assistive devices serve as vectors for the ideals, judgments, and goals that their society of origin has towards people with disabilities. For some Ugandan inventors and prosthetists, familiarity with sociocultural norms and consistent feedback allow them to design prosthetic limbs as technologies of care that specifically meet the needs of Ugandans using these devices. In contrast, many biomedical engineers living in the United States rely on what I call the "engineering imaginary" to produce universalized forms of assistive technology intended for people living in an essentialized Global South. Drawing on research with engineers, prosthetists, and people living with limb loss in Uganda and the United States, I investigate the social and cultural aspects of prosthetic limb design and argue that there is a cross-cultural mismatch about what a prosthetic device does and what kinds of limbs it should fit. This mismatch becomes inscribed in the prosthetic device itself.

The role of CD1d-restricted NKT cells in the clearance of Pseudomonas aeruginosa from the lung is dependent on the host genetic background.

Pseudomonas aeruginosa is an important human opportunistic pathogen, accounting for a significant fraction of hospital-acquired lung infections. CD1d-restricted NKT cells comprise an unusual innate-like T cell subset that plays important roles in both bacterial and viral infections. Previous reports have differed in their conclusions regarding the role of NKT cells in clearance of P. aeruginosa from the lung. Since there is significant strain-dependent variation in NKT cell number and function among different inbred strains of mice, we investigated whether the role of NKT cells was dependent on the host genetic background. We found that NKT cells did indeed play a critical role in the clearance of P. aeruginosa from the lungs of BALB/c mice but that they played no discernible role in clearance from the lungs of C57BL/6 mice. We found that the strain-dependent role of NKT cells was associated with significant strain-dependent differences in cytokine production by lung NKT cells and that impaired clearance of P. aeruginosa in BALB/c CD1d(-/-) mice was associated with an increase in neutrophil influx to the lung and increased levels of proinflammatory cytokines and chemokines after infection. Finally, we found that the role of alveolar macrophages was also dependent on the genetic background. These data provide further support for a model in which the unusually high level of variability in NKT cell number and function among different genetic backgrounds may be an important contributor to infectious-disease susceptibility and pathology.

Evaluation of simulation-based training model on vascular anastomotic skills for surgical residents.

INTRODUCTION: Reduced work hours and concerns over patient safety have encouraged surgical educators to find methods to advance resident skills more efficiently. Simulation provides the opportunity to improve technical surgical skills outside the operating room. We hypothesized that practice on surgical task simulators would improve residents' technical performance of vascular anastomotic technique. METHODS: Senior general surgery residents at an academic medical center completed pretests and posttests on 3 vascular surgery simulators: femoral-popliteal bypass, carotid endarterectomy, and abdominal aortic aneurysm repair. The initial training sessions began with a 15-minute instructional video on how to perform the procedures, followed by supervised sessions in anastomotic technique with attending vascular surgeons. Initial individual sessions were videotaped as a pretest, and the final attempt was videotaped as the posttest. Each test was evaluated by a single experienced attending vascular surgeon blinded to the examinees. Anastomoses were graded using a performance rating and a modified objective structured assessment of technical skill rating. Results were analyzed using mixed model P values. RESULTS: The residents showed statistically significant improvement between the pretest and the posttest in both their performance rating (1.9 vs. 2.4, P = 0.02) and the objective structured assessment of technical skill (2.6 vs. 3.1, P = 0.01), as well as in most subsets of each assessment scale. CONCLUSIONS: We conclude that practice using simulated anastomotic models leads to measurable improvement in vascular anastomotic technique in senior general surgery residents.

Plasma coagulation markers in patients with solid tumors and venous thromboembolic disease receiving oral anticoagulation therapy.

PURPOSE: To correlate the concentration of plasma coagulation markers at baseline and during follow-up in patients with solid tumors and venous thromboembolic disease with the risk of recurrence and death. EXPERIMENTAL DESIGN: Patients (N = 223) with first episode of venous thromboembolic disease received oral anticoagulation with warfarin for a target international normalized ratio of 2 to 3. Plasma coagulation markers were measured before instituting warfarin and at 3 monthly intervals, thereafter. RESULTS: The median duration of oral anticoagulation was 6.7 months (range 2 weeks to 11 months). Major bleeding episodes occurred in 18 patients (8%), and minor hemorrhagic events occurred in 15 (6.7%) patients. Patients with advanced malignancy (P = 0.032), history of surgery (P = 0.057), and those with poor performance status (P = 0.001) were more likely to encounter major bleeding episodes. Recurrence of venous thromboembolic disease was diagnosed in 31 patients (14%). At univariate analysis, advanced stage of cancer (P = 0.03), performance status > 1 (P = 0.001), treatment with chemotherapy (P = 0.01), the presence of metastatic liver disease (P = 0.03), higher d-dimer (P = 0.001), and thrombin antithrombin complex levels (P = 0.01) were features predictive of recurrent venous thromboembolic disease. At multivariate analysis, poor performance status (P = 0.01) and d-dimer levels (P = 0.001) were predictors of recurrent venous thromboembolic disease. Persistent activation of coagulation as indicated by an upward trend in d-dimer (P = 0.001) and antithrombin (P = 0.001) was observed in patients who developed recurrent thrombosis. Similar upward trends in d-dimer (P = 0.001), antithrombin (P = 0.001), and prothrombin fragment F1 + 2 (P = 0.001) was observed in the 76 patients who died during the study period and in the patients who received chemotherapy. CONCLUSIONS: Successful oral anticoagulation with warfarin in patients with cancer and venous thromboembolic disease is more likely to be achieved in patients with early stage tumors and good performance status. The persistence of activation of hemostasis as shown by plasma coagulation markers is a strong predictor of recurrence and poor outcome.

Erythropoietin modulates the anticancer activity of chemotherapeutic drugs in a murine lung cancer model.

In this study, we assessed the ability of erythropoietin (EPO) to synergize with various chemotherapeutic agents and suppress the growth and metastasis of solid tumors. Animals were inoculated with Lewis lung carcinoma (LLC) cells and treated with EPO alone, the designated chemotherapeutic drug (cisplatin, mitomycin C or cyclophoshamide) alone, or EPO and the drug. Tumor volume was monitored daily. Thirteen days following cell injection, tumor mass was determined. In addition, the number of the metastatic foci in the lungs was determined. Cisplatin alone was capable of inducing a 7-fold decrease in final tumor volume compared to tumor-bearing animals injected with saline. However, when EPO was combined with cisplatin, the animals experienced an 11-fold reduction in final tumor volume compared to saline-injected animals (P<0.001). A 2.5-fold reduction in tumor mass was observed in animals treated with cisplatin, compared to the saline-injected groups. Furthermore, injections of EPO and cisplatin induced a 4-fold reduction in tumor mass (P<0.001). Blood analysis indicated that a significant increase of more than 30% in WBC was found in animals injected concurrently with cisplatin and EPO, as compared to saline-injected mice (P<0.03). When EPO and mitomycin C were injected together, tumor mass was further reduced by 14% compared to that seen in mice treated with mitomycin C alone. However, this difference was not statistically significant. We conclude from this study that EPO can synergize with chemotherapeutic agents to further suppress the growth of tumors. The level of synergism is drug related.