Comparison of laser surface scanning and fiducial marker-based registration in frameless stereotaxy. Technical note

The authors compared the accuracy of laser surface scanning patient registration using the commercially available Fazer (Medtronic, Inc.) with the conventional registration procedure based on fiducial markers (FMs) in computer-assisted surgery. Four anatomical head specimens were prepared with 10 titanium microscrews placed at defined locations and scanned with a 16-slice spiral computed tomography unit. To compare the two registration methods, each method was applied five times for each cadaveric specimen; thus data were obtained from 40 registrations. Five microscrews (selected following a randomization protocol) were used for each FM-based registration; the other five FMs were selected for coordinate measurements by touching with a point measurement stylus. Coordinates of these points were also measured manually on the screen of the navigation computer. Coordinates were measured in the same manner after laser surface registration. The root mean square error as calculated by the navigation system ranged from 1.3 to 3.2 mm (mean 1.8 mm) with the Fazer and from 0.3 to 1.8 mm (mean 1.0 mm) with FM-based registration. The overall mean deviations (the arithmetic mean of the mean deviations of measurements on the four specimens) were 3.0 mm (standard deviation [SD] range 1.4-2.6 mm) with the Fazer and 1.4 mm (SD range 0.4-0.9 mm) with the FMs. The Fazer registration scans 300 surface points. Statistical tests showed the difference in the accuracy of these methods to be highly significant. In accordance with the findings of other groups, the authors concluded that the inclusion of a larger number of registration points might improve the accuracy of Fazer registration.     

Thick Slices from Tomosynthesis Data Sets: Phantom Study for the Evaluation of Different Algorithms

PURPOSE  

Tomosynthesis is a 3-dimensional mammography technique that generates thin slices separated one to the other by typically 1 mm from source data sets. The relatively high image noise in these thin slices raises the value of 1-cm thick slices computed from the set of reconstructed slices for image interpretation. In an initial evaluation, we investigated the potential of different algorithms for generating thick slices from tomosynthesis source data (maximum intensity projection—MIP; average algorithm—AV, and image generation by means of a new algorithm, so-called softMip). The three postprocessing techniques were evaluated using a homogeneous phantom with one textured slab with a total thickness of about 5 cm in which two 0.5-cm-thick slabs contained objects to simulate microcalcifications, spiculated masses, and round masses. The phantom was examined by tomosynthesis (GE Healthcare). Microcalcifications were simulated by inclusion of calcium particles of four different sizes. The slabs containing the inclusions were examined in two different configurations: adjacent to each other and close to the detector and with the two slabs separated by two 1-cm thick breast equivalent material slabs. The reconstructed tomosynthesis slices were postprocessed using MIP, AV, and softMip to generate 1-cm thick slices with a lower noise level. The three postprocessing algorithms were assessed by calculating the resulting contrast versus background for the simulated microcalcifications and contrast-to-noise ratios (CNR) for the other objects. The CNRs of the simulated round and spiculated masses were most favorable for the thick slices generated with the average algorithm, followed by softMip and MIP. Contrast of the simulated microcalcifications was best for MIP, followed by softMip and average projections. Our results suggest that the additional generation of thick slices may improve the visualization of objects in tomosynthesis. This improvement differs from the different algorithms for microcalcifications, speculated objects, and round masses. SoftMip is a new approach combining features of MIP and average showing image properties in between MIP and AV.     

Accessory-Cell-Mediated Activation of Porcine NK Cells by Toll-Like Receptor 7 (TLR7) and TLR8 Agonists

The induction of innate immune responses by toll-like receptor (TLR) agonists is the subject of intense investigation. In large part, this reflects the potential of such compounds to be effective vaccine adjuvants. For that reason, we analyzed the activation of innate cells in swine by TLR7 and TLR8 agonists. These agonists activated porcine NK cells by increasing gamma interferon (IFN-γ) expression and perforin storage. The activation of porcine NK cells was mediated by accessory cells, since their depletion resulted in reduced cytotoxicity toward target cells. Accessory cells were stimulated to produce interleukin 12 (IL-12), IL-15, IL-18, and IFN-α after treatment with TLR7 or TLR8 agonists. Neutralization of these cytokines reduced but did not completely inhibit the induction of NK cell cytotoxicity. Direct stimulation of NK cells with TLR7 or TLR8 agonists resulted in minimal cytotoxicity but levels of IFN-γ equivalent to those detected in the presence of accessory cells. Porcine NK cells express both TLR7 and TLR8 mRNAs, and treatment with these TLR agonists induced higher mRNA expression levels of TRAIL and IL-15Rα, which may contribute to the activity of NK cells. These data indicate that TLR7 and TLR8 agonists indirectly or directly activate porcine NK cells but that optimum levels of activation require cytokine secretion by accessory cells activated by these compounds. Interestingly, NK cells activated by TLR7 or TLR8 agonists were cytotoxic against foot-and-mouth disease virus (FMDV)-infected cells in vitro, indicating that these TLR agonists may be beneficial as adjuvants to stimulate the innate immunity against FMDV.Toll-like receptors (TLRs) are pathogen-associated molecular pattern recognition receptors responsible for signaling intrusion by pathogens. These receptors are expressed by cells mediating innate responses. Pathogens are recognized directly by the binding of pathogen-associated molecules. For example, TLR3 recognizes double-stranded RNA during virus replication; TLR5 binds bacterial flagellin; TLR9 detects nonmethylated, CG-rich prokaryotic DNA, i.e., CpG; and TLR7 and TLR8 recognize single-stranded RNA (44), although recognition by TLR8 may be species specific, as demonstrated recently by Forsbach et al. (11). The consequence of engaging TLRs is the induction of signals that lead to the expression of proinflammatory cytokines, antimicrobial and antiviral effector molecules, and costimulatory molecules on macrophages (Mφ) and dendritic cells (DCs) (25, 39). Overall, such events affect the activation and functional status of innate immune cells, such as natural killer (NK) cells and DCs, and further influence the organization of adaptive immune responses.NK cells perform a critical role in innate immunity, leading to protection against various pathogens well before the adaptive immune responses develop. NK cells are lymphocyte-derived cells that engage nonspecific target recognition mechanisms to eliminate malignant or virus-infected cells (10). However, it has recently been shown that some receptors on NK cells engage viral gene products. For example, Ly49H recognizes m157 of murine cytomegalovirus in mice, while NKp44 and NKp46 bind influenza virus hemagglutinin (4, 27). Moreover, NK cells express both inhibitory and activating receptors, which directly influence the outcome of NK cell activation. Besides the expression of such receptors (22), NK cells have other mechanisms that enhance their function as natural spontaneous effector cells (24). Such mechanisms include the expression of TLRs, which possibly allow NK cells to respond to the presence of pathogens by direct activation via these receptors.NK cells express TLR9 in mice (26) and TLR1 to TLR10 in humans (12, 17, 23). However, not much information is currently available on the expression of these receptors on immune cells of domestic livestock species, such as porcine or bovine species. Direct stimulation of human NK cells through TLR2, TLR3, TLR7, and TLR8 leads to the upregulation of gamma interferon (IFN-γ) secretion, although in some instances this response requires the presence of interleukin 12 (IL-12) (6, 12, 17). Furthermore, activation via TLR5 is reported to stimulate NK cell proliferation but not IFN-γ production (45). Additionally, stimulation via TLR2 or TLR7 induces chemokines such as CCL3, CCL4, and CCL5 (36). Although TLR9 is expressed in NK cells, it does not induce IFN-γ production directly unless the NK cells are presented with antibody-coated target cells or are cultured on plates with an immobilized antibody against immunoglobulin G (35). Therefore, TLR expression in NK cells may be involved in the differential regulation of these vital cells of the innate response. However, not much is known about the direct effect of TLR stimulation on the expression of NK cell effector molecules, such as perforin, granzymes, and cytokines.Using this class of molecules, it is now possible to formulate vaccine adjuvants that prime cell-mediated immunity. Engaging TLR receptors with specific synthetic agonists introduces a new way of inducing early innate responses as well as increasing the potency of adaptive immunity. The importance of such an approach is exemplified by several clinical studies currently under way. TLR9 and TLR4 agonist are being tested as vaccine adjuvants, and a TLR7 agonist is being tested in the treatment of genital warts caused by herpes simplex virus (28). In addition, TLR4 is being tested for the treatment of allergies, endotoxemia, and liver disease, TLR7 for cancer treatment, and TLR9 as a treatment for melanoma (reviewed by Ulevitch [46]).Foot-and-mouth disease virus (FMDV) infects cloven-hoofed animals, leading to devastating economic consequences (16). This is a highly contagious viral infection that causes a very acute disease. Clinical symptoms are detected within 1 or 2 days of exposure and resolve within a week to 10 days. Viral clearance may be mediated in part by antibodies, but under controlled experimental conditions, viremia is gone by day 3 or 4 after infection when anti-FMDV immunoglobulin M is barely detectable (2, 13). These results strongly suggest that other antiviral mechanisms contribute to the elimination of the virus in vivo. Innate responses, including the activation of DCs and NK cells, are likely involved.Therapeutic approaches involving TLR stimulation via synthetic agonists can augment innate responses, indicating that such therapeutics have the potential to induce early protection against foot-and-mouth disease (29, 30). Therefore, we have studied the effects of TLR agonists on porcine NK cells in vitro. We report that TLR7 and TLR8 agonists and a combined TLR7/8 agonist activate porcine CD2⁺ CD8⁺ CD3⁻ NK cells through accessory-cell-mediated mechanisms, such as the secretion of cytokines, including IFN-α, IL-12, IL-15, and IL-18. In addition, porcine NK cells are partially activated by the direct interaction of TLR7 and TLR8 agonists through these receptors expressed by NK cells. Activated cells show enhanced secretion of IFN-γ and storage of perforin granules and can effectively lyse tumor or FMDV-infected targets. These results are discussed in the context of rational approaches to antiviral measures against FMDV.     

Presence of corrosion products and hypersensitivity-associated reactions in periprosthetic tissue after aseptic loosening of total hip replacements with metal bearing surfaces

Aseptic loosening of articular implants is frequently associated with tissue reactions to wear particles. Some patients, who had received metal-on-metal articulations, present early symptoms including persistent pain and implant failure. These symptoms raise the suspicion about the development of an immunological response. Furthermore, the generation of rare corrosion products in association with metallic implants has been observed. Corrosion products are known to enhance third-body wear and contribute to the loss of the implant. The purpose of this study was to investigate periprosthetic tissue containing solid corrosion products after aseptic loosening of second-generation metal-on-metal total hip replacements made of low-carbon cobalt-chromium-molybdenum alloy for the presence of immunologically determined tissue changes. Periprosthetic tissue of 11 cases containing uncommon solid deposits was investigated by light microscopy. In order to confirm the presence of corrosion products, additional methods including scanning electron microscopy (SEM) investigation, energy dispersive X-ray (EDX) and Fourier transform infrared microspectroscopy (FTIR) analysis were used. All investigated cases revealed solid chromium orthophosphate corrosion products as well as metallic wear particles to a various extent. Moreover, various intense tissue reactions characteristic of immune response were observed in all cases. The simultaneous presence of corrosion products and hypersensitivity-associated tissue reaction indicates that a relationship between corrosion development and implant-related hypersensitivity may exist.     

Induction of adaptive immunity by flagellin does not require robust activation of innate immunity

The ability of TLR agonists to promote adaptive immune responses is attributed to their ability to robustly activate innate immunity. However, it has been observed that, for adjuvants in actual use in research and vaccination, TLR signaling is dispensable for generating humoral immunity. Here, we examined the role of TLR5 and MyD88 in promoting innate and humoral immunity to flagellin using a prime/boost immunization regimen. We observed that eliminating TLR5 greatly reduced flagellin‐induced cytokine production, except for IL‐18, and ablated DC maturation but did not significantly impact flagellin's ability to promote humoral immunity. Elimination of MyD88, which will ablate signaling through TLR and IL‐1β/IL‐18 generated by Nod‐like receptors, reduced, but did not eliminate flagellin's promotion of humoral immunity. In contrast, loss of the innate immune receptor for profilin‐like protein (PLP), TLR11, greatly reduced the ability of PLP to elicit humoral immunity. Together, these results indicate that, firstly, the degree of innate immune activation induced by TLR agonists may be in great excess of that needed to promote humoral immunity and, secondly, there is considerable redundancy in mechanisms that promote the humoral immune response upon innate immune recognition of flagellin. Thus, it should be possible to design innate immune activators that are highly effective vaccine adjuvants yet avoid the adverse events associated with systemic TLR activation.     

Hemostatic properties of a venomic protein in rat organ trauma

Previous in vitro work characterized the protease Q8009 isolated from the venom of the Australian brown snake Pseudonaja textilis textilis with Factor Xa-like activity and hemostatic properties. The purpose of the work described here characterizes the in vivo hemostatic properties in a rat model of parenchymatous organ injury. The key parameters of activity included reduction in time-to-hemostasis and total volume of blood loss in spleen, liver and kidney wound models in rats. The surgical protocols involved exposure of the organs via a midline abdominal laparotomy. Using a clean metal template with 6, 6.5, 9 mm holes for spleen, liver and kidney, respectively, a predetermined volume of the organ was gently extruded through the template hole and excised with a razor blade. About 50 to 75 μL of collagen matrix with the different test solutions was applied to the wounds. Blood was collected and at the end of the procedure animals were humanely sacrificed with an anesthetic overdose. Determination of blood was performed using the hematin assay using a standard curve. Blood loss per minute and total blood loss were calculated. Results from the studies demonstrated that the application of Q8009 and collagen matrix to surgical wounds significantly reduced the total amount of blood loss and the time-to-hemostasis. In the spleen wound model, Q8009 at 100, 250 and 1000 μg/ml significantly reduced (p < 0.001) the total volume of blood lost relative to thrombin and reduced the time-to-hemostasis by 25-50%, as compared to 7% by thrombin. In the liver wound model, Q8009 at 250 and 1000 μg/ml significantly reduced (p < 0.001) the total volume of blood lost relative to thrombin and reduced the time-to-hemostasis from 10.5 min by thrombin to 5.6 min with Q8009. In the kidney wound model, Q8009 at 250 μg/ml significantly reduced (p < 0.05) the total volume of blood lost and reduced the time-to-hemostasis by 25% when compared to thrombin. The hemostasis levels were consistent with previous findings in skin wound rat models where Q8009 consistently reduced the total volume of blood lost and shortened time-to-hemostasis. Application of Q8009 plus collagen matrix significantly reduced the volume of total blood loss and time-to-hemostasis in rat surgical organ wound models induced bleeding, as compared to a commercially available hemostat device. The protein Q8009 has greater capacity to reduce blood loss and shorten time-to-hemostasis; highly desirable properties where rapid hemostasis is needed in surgical wounds in parenchymatous organs.     

Adjunctive lacosamide for partial-onset seizures: Efficacy and safety results from a randomized controlled trial

Purpose:   To evaluate the efficacy and safety of lacosamide (200 and 400 mg/day) when added to one to three concomitant antiepileptic drugs (AEDs) in patients with uncontrolled partial-onset seizures.
Methods:   This multicenter, double-blind, placebo-controlled trial randomized patients (age 16–70 years) with partial-onset seizures with or without secondary generalization to placebo, lacosamide 200, or lacosamide 400 mg/day. The trial consisted of an 8-week baseline, a 4-week titration, and a 12-week maintenance period.
Results:   Four hundred eighty-five patients were randomized and received trial medication. Among these, 87% were taking two or more concomitant AEDs. Median percent reduction in seizure frequency per 28 days from baseline to maintenance period (intent-to-treat, ITT) was 20.5% for placebo, 35.3% for lacosamide 200 mg/day (p   =   0.02), and 36.4% for 400 mg/day (p   =   0.03). In the per protocol population, the reductions were 35.3% for lacosamide 200 mg/day (p   =   0.04) and 44.9% for 400 mg/day (p   =   0.01) compared to placebo (25.4%). The 50% responder rate for lacosamide 400 mg/day (40.5%) was significant (p   =   0.01) over placebo (25.8%), but was not for 200 mg/day (35.0%). In the per protocol population, the 50% responder rate for lacosamide 400 mg/day (46.3%) was significant (p   <   0.01) compared with the placebo responder rate (27.5%). Dose-related adverse events (AEs) included dizziness, nausea, and vomiting. Clinically relevant changes in the mean plasma concentrations of commonly used AEDs were not observed.
Discussion:   Results of this trial demonstrated the efficacy and tolerability of adjunctive lacosamide 200 and 400 mg/day and support that lacosamide may be an advantageous option for the treatment of partial-onset seizures in patients with epilepsy.