Innate Immune Activation After Transfusion of Stored Red Blood Cells

The transfusion of red blood cells (RBCs), although necessary for treatment of anemia and blood loss, has also been linked to increased morbidity and mortality. RBCs stored for longer durations and transfused in larger volumes are often cited as contributory to adverse outcomes. The potential mechanisms underlying deleterious effects of RBC transfusion are just beginning to be elucidated. In this narrative review, we explore the hypothesis that prolonged RBC storage results in elaboration of substances which may function as danger associated molecular pattern molecules that activate the innate immune system with consequences unfavorable to healthy homeostasis. The nature of these chemical mediators and the biological responses to them offers insight into the mechanisms of these pathological responses. Three major areas of activation of the innate immune apparatus by stored RBCs have been tentatively identified: RBC hemolysis, recipient neutrophil priming, and reactive oxygen species production. The possible mechanisms by which each might perturb the innate immune response are reviewed in a search for potential novel pathways through which transfusion can lead to an altered inflammatory response.     

Using handheld computers for daily alcohol assessment: Results from a pilot study

Aims: The purpose of this pilot study was to determine the feasibility and usability of daily retrospective assessments of alcohol use using handheld computers and to explore their comparability to Timeline Followback (TLFB) assessments.

Methods: College student participants received a Handheld Assessment Tool (HAT) at enrolment, which surveyed alcohol consumption and contextual factors for the previous day. After 1 week of daily monitoring, participants completed a paper‐and‐pencil TLFB assessment and HAT usability scale.

Results: Of the 1,800 matched data points on the HAT and TLFB, the overall level of agreement was very good (kappa = 0.80, p<0.001). The mean difference between the number of drinks per drinking days recorded using both methods was 0.19 (SD = 0.56). Participants completed HAT surveys on 87 out of 91 total possible survey days (95.6%). The HAT recorded 34 drinking days and the TLFB recorded 37 out the 91 possible days; the HAT was reported to be highly usable by all participants.

Conclusion: Overall, the HAT was found to be usable and feasible and produced high adherence. Further research should validate this alcohol assessment approach and apply it to representative populations.     

Techniques for high-resolution MR imaging of atherosclerotic plaque

Atherosclerotic cardiovascular disease is the most common cause of death in the United States. Investigation of atherosclerotic plaque morphology and composition is important because the findings may be useful in predicting prognosis or response to therapy. This study presents high-resolution magnetic resonance (MR) imaging techniques developed on a 1.5-T whole-body imager with a custom-built surface coil, for characterizing the composition and morphology of plaque removed at carotid endarterectomy. The initial comparison of MR imaging and histologic results showed good correlation. In conjunction with MR angiography, these techniques could be used in in vivo imaging to define the size, location, and contents of atherosclerotic plaque at the carotid bifurcation.     

Reduction of flow-related signal loss in flow-compensated 3D TOF MR angiography, using variable echo time (3D TOF-VTE).

High-resolution MRA with phase/frequency flow compensation may require very long echo times (TEs). Variable TE (VTE) was implemented into flow-compensated 3D TOF to minimize the effective TE and reduce the flow-related signal void. The k-space of the 3D TOF was divided into segment groups ranging from two to 32 segments with different TEs. The TEs were minimized and the flow-compensation gradient lobes were calculated to null the total first moment at the peak of the echo for each segment. Possible artifacts and off-resonance effects were evaluated, with respect to the number of TE segments, using the point spread function (PSF) and corresponding experiments. The optimal number of TE segments for the least artifact was determined to be one-half of the number of slices. Two types of artifacts caused by VTE were predicted and subsequently observed. The developed pulse sequence 3D TOF-VTE was tested on clinical MRI systems, by performing scans of the cervical carotid artery and intracranial carotid artery at the carotid siphon. The signal distribution near the bifurcation and the siphon was much more uniform with VTE, and the flow-related signal loss was greatly reduced. The resultant MR angiograms provided improved vessel detail. The results show that VTE improved the quality of flow-compensated 3D TOF MRA.     

A prospective randomized comparison of patellar tendon versus semitendinosus and gracilis tendon autografts for anterior cruciate ligament reconstruction

Seventy patients with patellar tendon or hamstring tendon autografts for single-incision anterior cruciate ligament reconstruction were evaluated at least 2 years after surgery. All reconstructions were performed by the same surgeon, and metal interference screws were used for fixation of all grafts. No significant differences were noted between groups for Lysholm score, reduction in activity, KT-1000 arthrometer findings, quadriceps muscle size, return to sports, or ability to jump and do hard cuts and pivots. Significantly more patients in the patellar tendon group had patellofemoral pain at 6 months after surgery than did the hamstring tendon patients (48% versus 20%), and at last follow-up the incidence of patellofemoral pain was 42% and 20%, respectively. Fourteen patients in the patellar tendon group and seven in the hamstring tendon group had loss of motion (approximately 5 degrees ). Four patients (two in each group) had treatment failures and their results were not included in the clinical examination data. At 2 years' follow-up, 97% of patients with patellar tendon grafts and 100% of patients with hamstring tendon grafts rated their results as good or excellent. We found that hamstring tendon grafts performed similarly to patellar tendon grafts, although fewer patients in the hamstring tendon group had patellofemoral pain and loss of motion.