A defined mechanistic correlate of protection against Plasmodium falciparum malaria in non-human primates.

Malaria vaccine design and prioritization has been hindered by the lack of a mechanistic correlate of protection. We previously demonstrated a strong association between protection and merozoite-neutralizing antibody responses following vaccination of non-human primates against Plasmodium falciparum reticulocyte binding protein homolog 5 (PfRH5). Here, we test the mechanism of protection. Using mutant human IgG1 Fc regions engineered not to engage complement or FcR-dependent effector mechanisms, we produce merozoite-neutralizing and non-neutralizing anti-PfRH5 chimeric monoclonal antibodies (mAbs) and perform a passive transfer-P. falciparum challenge study in Aotus nancymaae monkeys. At the highest dose tested, 6/6 animals given the neutralizing PfRH5-binding mAb c2AC7 survive the challenge without treatment, compared to 0/6 animals given non-neutralizing PfRH5-binding mAb c4BA7 and 0/6 animals given an isotype control mAb. Our results address the controversy regarding whether merozoite-neutralizing antibody can cause protection against P. falciparum blood-stage infections, and highlight the quantitative challenge of achieving such protection.

Seroepidemiologic survey for Coxiella burnetii among US military personnel deployed to Southwest and Central Asia in 2005.

We used a seroepidemiologic study to estimate Q fever (Coxiella burnetii) seroprevalence, seroincidence, and risk factors for seroconversion in two deployed military populations in 2005. The first study group resided in an area with a known Q fever outbreak history (Al Asad, Iraq). Of this population, 7.2% seroconverted for an incidence rate of 10.6 seroconversions per 1,000 person-months. The second population included personnel transiting through Qatar on mid-deployment leave from southwest/central Asia. In this group, we found 2.1% prevalence with 0.92 seroconversions per 1,000 person-months. However, no significant risk factors for Q fever seroconversion were found in either population.

Assessment of postoperative analgesia after application of ultrasound-guided regional anesthesia for surgery in a swine femoral fracture model.

Management of pain in research swine used for studies involving painful procedures is a considerable challenge. Here we assessed whether a regional anesthesia method is effective for pain control of hindlimb injuries in pigs used for research in bone fracture healing. For this randomized controlled study, we administered regional anesthesia before an experimental femoral injury was produced. Using ultrasound guidance, we placed sterile infusion catheters near the sciatic and femoral nerves and administered local anesthetic (bupivacaine) for the first 24 h after surgery. We evaluated various behavioral and physiologic parameters to test the hypothesis that this regional anesthesia would provide superior analgesia compared with systemic analgesia alone. We also collected blood samples to evaluate serum levels of cortisol and fentanyl postoperatively. At the end of the study period, we collected sciatic and femoral nerves and surrounding soft tissues for histopathologic evaluation. Treatment pigs had lower subjective pain scores than did control animals. Control pigs had a longer time to first feed consumption and required additional analgesia earlier in the postoperative period than did treatment pigs. Ultrasound-guided regional anesthesia is a viable and effective adjunct to systemic analgesics for providing pain control in swine with experimental femoral fractures.

Multimodal noninvasive monitoring of soft tissue wound healing.

Here we report results of non-invasive measurements of indirect markers of soft tissue healing of traumatic wounds in an observational swine study and describe the quantification of analog physiological signals. The primary purpose of the study was to measure bone healing of fractures with four different wound treatments. A second purpose was to quantify soft tissue wound healing by measuring the following indirect markers: (1) tissue oxygenation, (2) fluid content, and (3) blood flow, which were all measured by non-invasive modalities, measured with available devices. Tissue oxygenation was measured by near infrared spectroscopy; fluid content was measured by bipolar bio-impedance; and blood flow was measured by Doppler ultrasound. Immediately after comminuted femur fractures were produced in the right hind legs of thirty anesthetized female Yorkshire swine, one of four wound treatments was instilled into each wound. The four wound treatments were as follows: salmon fibrinogen/thrombin-n = 8; commercial bone filler matrix-n = 7; bovine collagen-n = 8; porcine fibrinogen/thrombin-n = 7. Fractures were stabilized with an external fixation device. Immediately following wound treatments, measurements were made of tissue oxygenation, fluid content and blood flow; these measurements were repeated weekly for 3 weeks after surgery. Analog signals of each modality were recorded on both the wounded (right) hind leg and the healthy (left) hind leg, for comparison purposes. Data were processed off-line. The mean values of 10-s periods were calculated for right-left leg comparison. ANOVA was applied for statistical analysis. Results of the bone healing studies are published separately (Rothwell et al. in J Spec Oper Med 13:7-18, 2013). For soft tissue wounds, healing did not differ significantly among the four wound treatments; however, regional oxygenation of wounds treated with salmon fibrinogen/thrombin showed slightly different time trends. Further studies are needed to establish standards for healthy wound healing and for detection of pathological alterations such as infection. Non-invasive measurement and quantification of indirect markers of soft tissue wound healing support the goals and principles of evidence-based medicine and show potential as easy to administer tools for clinicians and battlefield medical personnel to apply when procedures such as the PET scan are not available or affordable. The method we developed for storing analog physiological signals could be used for maintaining electronic health records, by incorporating vital signs such as ECG and EEG, etc.

Comparison of fibrinogen- and collagen-based treatments for penetrating wounds with comminuted femur fractures in a Swine model.

INTRODUCTION: Military servicemembers in combat operations often sustain injuries to the extremities from highspeed projectiles, resulting in bleeding and comminuted open fractures. Severe injury with bone fragmentation can result in limb amputation. Surgical treatment options include materials that promote osteogenesis and bone proliferation, such as growth hormones, stem cells, or mineralized matrix adjuncts. However, none of these are amenable to use by the first responder, nor do they address the question of hemorrhage control, which is a common problem in traumatic injuries. HYPOTHESIS: Our hypothesis was that treatment with a fibrinogen-based protein mixture at the time of the bone injury will provide both hemostasis and a supportive environment for preservation of injured bone. METHODS: A comminuted femur fracture was produced in 28 female Yorkshire swine, and one of four treatments was instilled into the wound immediately after injury. Each animal was evaluated for the following parameters: inflammation, new bone growth, osteoclast proliferation, callus formation, and femur wound cavity fill, using post-mortem computed tomography and analysis of histological sections. RESULTS: Overall, salmon fibrinogen?thrombin and porcine fibrinogen?thrombin showed a trend for improved healing based on bone filling and calcification. However, statistically significant differences could not be established between treatment groups. CONCLUSIONS: These findings indicate that a fibrinogen?thrombin matrix may be a useful as an immediate response product to enhance fracture healing. Salmon fibrinogen?thrombin has the advantages of cost and a pathogen profile compared to mammalian fibrinogens.

Planning and operational considerations for units utilizing military working dogs.

Military working dogs are rapidly becoming integral to military operations. While they bring many valuable capabilities to the battlefield, it is important that Special Operations leaders consider canine team capabilities and requirements when planning missions. Careful logistical and operational planning can optimize the health, performance, and readiness of the working dog while protecting the safety and well-being of the team members working with them. We also offer recommendations for medical treatment of dog bites.

Functional genomics of chicken, mouse, and human titin supports splice diversity as an important mechanism for regulating biomechanics of striated muscle.

Titin is a giant filamentous elastic protein that spans from the Z-disk to M-band regions of the sarcomere. The I-band region of titin is extensible and develops passive force in stretched sarcomeres. This force has been implicated as a factor involved in regulating cardiac contraction. To better understand the adaptation in the extensible region of titin, we report the sequence and annotation of the chicken and mouse titin genes and compare them to the human titin gene. Our results reveal a high degree of conservation within the genomic region encoding the A-band segment of titin, consistent with the structural similarity of vertebrate A-bands. In contrast, the genomic region encoding the Z-disk and I-band segments is highly divergent. This is most prominent within the central I-band segment, where chicken titin has fewer but larger PEVK exons (up to 1,992 bp). Furthermore, in mouse titin we found two LINE repeats that are inserted in the Z-disk and I-band regions, the regions that account for most of the splice isoform diversity. Transcript studies show that a group of 55 I-band exons is differentially expressed in chicken titin. Consistent with a large degree of titin isoform plasticity and variation in PEVK content, chicken skeletal titins range in size from approximately 3,000 to approximately 3,700 kDa and vary greatly in passive mechanical properties. Low-angle X-ray diffraction experiments reveal significant differences in myofilament lattice spacing that correlate with titin isoform expression. We conclude that titin splice diversity regulates structure and biomechanics of the sarcomere.