Neutrophil-dependent acute lung injury. Requirement for P-selectin (GMP-140).

Rapid translocation of P-selectin (GMP-140) from cytoplasmic granules to the cell membrane of endothelial cells promotes adhesive interactions with neutrophils which, when activated, damage the endothelium. The role of P-selectin in lung vascular endothelial injury in rats after systemic activation of complement by intravenous infusion of cobra venom factor has been assessed. Within 5-10 min after cobra venom factor infusion, the pulmonary vasculature demonstrated immunohistochemical expression of an epitope that reacts with anti-human P-selectin. Monoclonal antibody to human P-selectin blocked in vitro adherence of rat or human platelets (activated with thrombin) to neutrophils and was demonstrated to react with thrombin-activated rat platelets. The antibody did not react with rat neutrophils. In vivo, the antibody had strongly protective effects against cobra venom factor-induced pulmonary vascular injury as determined by permeability changes and hemorrhage. In parallel, lung myeloperoxidase content was greatly reduced and, by transmission electron microscopy, there was markedly diminished adherence of neutrophils to the pulmonary vascular endothelium and much diminished injury of endothelial cells, as defined by hemorrhage. These data indicate that anti-human P-selectin reacts with a pulmonary vascular antigen in rats and that this antigen is essential for the full expression of lung injury.     

Analgesia and effectiveness of levobupivacaine compared with ropivacaine in patients undergoing an axillary brachial plexus block

A common anesthetic technique for the upper extremity is local brachial plexus anesthesia using levobupivacaine and ropivacaine. To our knowledge, no study has been performed measuring differences in analgesic efficacy and latency when these local anesthetics are used for brachial plexus anesthesia. We enrolled 54 adults, assessed as ASA class I or II, into this double-blind, prospective investigation to receive 40 mL of 0.5% ropivacaine or levobupivacaine with 1:200,000 epinephrine. Pain was assessed using a 0 to 10 verbal numeric rating scale (VNRS). Motor blockade was determined using a modified Bromage scale. Variables included analgesic duration, latency, and overall patient satisfaction. The ropivacaine group had significantly higher VNRS scores at the 8th (P= .001) and 10th (P = .003) postoperative hours. The duration of sensory analgesia was significantly longer in the levobupivacaine group (831 minutes) than in the ropivacaine group (642 minutes, P = .013). Return of motor activity was significantly faster in the ropivacaine group (778 minutes) than in the levobupivacaine group (1,047 minutes; P = .001). No other significant differences were noted between the groups. When considering levobupivacaine and ropivacaine for brachial plexus anesthesia, levobupivacaine should be considered when postoperative analgesia is a concern but not when an early return of motor activity is required.     

Association of familial and sporadic rheumatoid arthritis with a single corticotropin-releasing hormone genomic region (8q12.3) haplotype

OBJECTIVE: Rheumatoid arthritis (RA) is a common disabling autoimmune disease with a complex genetic component. We have previously described linkage of a region of chromosome 8q12.3 with RA and association of the microsatellite marker CRHRA1 with RA in 295 affected sibling-pair families. In the current study we aimed to physically link the RA-associated marker with the corticotropin-releasing hormone (CRH) candidate gene, and to examine the genomic region for additional short tandem repeat (STR) genetic markers in order to clarify the association with RA. METHODS: We examined the association of 2 STR markers with disease in the original 295 multicase families and in a cohort of 131 simplex families to refine our understanding of this genetic region in disease susceptibility in sporadic and familial RA. Genomic library screening and sequencing were used to generate physical sequences in the CRH genomic region. Bioinformatic analysis of the sequence flanking the CRH structural gene was used to screen for additional STRs and other genetic features. Genotyping was carried out using a standard fluorescence approach. Estimations of haplotype frequencies were performed to assess linkage disequilibrium. The transmission disequilibrium test was performed using TRANSMIT. RESULTS: Physical cloning and sequencing analyses identified the genomic region linking the CRHRA1 marker and the CRH structural locus. Moreover, we identified a further STR, CRHRA2, which was in strong linkage disequilibrium with CRHRA1 (P = 4.0 x 10(-14)). A haplotype, CRHRA1*10;CRHRA2*14, was preferentially carried by unaffected parents at a frequency of 8.6% compared with the expected frequency of 3.1%. This haplotype was overtransmitted in the multiply affected families (P = 0.0077) and, similarly, in the simplex families (P = 0.024). Combined analysis of both family cohorts confirmed significant evidence for linkage (P = 4.9 x 10(-4)) and association (P = 5.5 x 10(-3)) for this haplotype with RA. CONCLUSION: In demonstrating significant linkage disequilibrium between these 2 markers, we have refined the disease-associated region to a single haplotype and confirmed the significance of this region in our understanding of the genetics of RA.     

Functional and biophysical analyses of the class XIV Toxoplasma gondii Myosin D

Summary The obligate intracellular parasite Toxoplasma gondii uses gliding motility to migrate across the biological barriers of the host and to invade cells. This unique form of locomotion requires an intact actin cytoskeleton and involves at least one motor protein (TgMyoA) that belongs to the class XIV of the myosin superfamily. TgMyoA is anchored in the inner membrane complex and is essential for the gliding motion, host cell invasion and egress of T. gondii tachyzoites. TgMyoD is the smallest T. gondii myosin and is structurally very closely related to TgMyoA. We show here that TgMyoD exhibits similar transient kinetic properties as the fast single-headed TgMyoA. To determine if TgMyoD also contributes to parasite gliding motility, the TgMyoD gene was disrupted by double homologous recombination. In contrast to TgMyoA, TgMyoD gene is dispensable for tachyzoite propagation and motility. Parasites lacking TgMyoD glide normally and their virulence is not compromised in mice. The fact that TgMyoD is predominantly expressed in bradyzoites explains the absence of a phenotype observed with myodko in tachyzoites and does not exclude a role of this motor in gliding that would be restricted to the cyst forming but nevertheless motile stage of the parasite.Both authors contributed equally to the work.     

Contrasting signatures of selection on the Plasmodium falciparum erythrocyte binding antigen gene family

Erythrocyte binding antigens of Plasmodium falciparum are involved in erythrocyte invasion, and may be targets of acquired immunity. Of the five eba genes, protein products have been detected for eba-175, eba-181 and eba-140, but not for psieba-165 or ebl-1, providing opportunity for comparative analysis of genetic variation to identify selection. Region II of each of these genes was sequenced from a cross-sectional sample of parasites in an endemic Kenyan population, and the frequency distributions of polymorphisms analysed. A positive value of Tajima's D was observed for eba-175 (D=1.13) indicating an excess of intermediate frequency polymorphisms, while all other genes had negative values, the most negative being ebl-1 (D=-2.35) followed by psieba-165 (D=-1.79). The eba-175 and ebl-1 genes were then studied in a sample of parasites from Thailand, for which a positive Tajima's D value was again observed for eba-175 (D=1.79), and a negative value for ebl-1 (D=-1.85). This indicates that eba-175 is under balancing selection in each population, in strong contrast to the other members of the gene family, particularly ebl-1 and psieba-165 that may have been under recent directional selection. Population expansion simulations were performed under a neutral model, further supporting the departures from neutrality of these genes.     

Micro-computed tomography evaluation of the glenoid fossa and mandibular condyle bone after bilateral vertical ramus mandibular distraction in a canine model

The aim of this study was to quantify bone microarchitecture within the glenoid fossa and mandibular condyle following mandibular distraction osteogenesis. Eight 6- to 9-month-old male beagle dogs underwent bilateral vertical mandibular distraction with semiburied distractors (12 days of distraction at 1 mm per day). One unoperated animal served as control. After distraction the animals were divided into two groups (N = 4) and killed after 1 or 2 months of consolidation. Three-dimensional trabecular architecture was analyzed by micro-computed tomography (microCT). At both sites the overall trends were similar. In the glenoid fossa, there was decreased bone volume, trabecular number, and connectivity density and increased trabecular separation at 1 month and decreased trabecular thickness and increased structure model index compared with the control (P < 0.05). In the mandibular condyle, there was decreased bone volume, trabecular number, and connectivity density at both 1 and 2 months, with decreased trabecular thickness and increased structure model index at 2 months only compared with the control (P < 0.05). The bone became less dense and more rodlike. These bone changes are similar to those seen by the effects of aging or impaired normal function. Thus, in the short term, changes occur in the bone microstructure of the glenoid fossa and mandibular condyle after vertical mandibular ramus distraction in the canine model.     

Naturally acquired antibodies to polymorphic and conserved epitopes of Plasmodium falciparum merozoite surface protein 3

Many studies on the role of merozoite surface protein 3 (MSP3) in immunity against malaria have focused on a conserved section of MSP3. New evidence suggests that polymorphic sequences within MSP3 are under immune selection. We report a detailed analysis of naturally-acquired antibodies to allele-specific and conserved parts of MSP3 in a Kenyan cohort. Indirect and competition ELISA to heterologous recombinant MSP3 proteins were used for antibody assays, and parasites were genotyped for msp3 alleles. Antibody reactivity to allele-specific and conserved epitopes of MSP3 was heterogeneous between individuals. Overall, the prevalence of allele-specific antibody reactivity was significantly higher (3D7-specific 54%, K1-specific 41%) than that to a recombinant protein representing a conserved portion of C-terminal MSP3 (24%, P < 0.01). The most abundant IgG subclass was IgG3, followed by IgG1. Allele-specific reactivity to the K1-type of MSP3 was associated with a lower risk of clinical malaria episodes during a 6-month follow-up in individuals who were parasitized at the start of the malaria transmission season (Relative risk 0.41 with 95% confidence interval 0.20-0.81, P = 0.011). The potential importance of allele-specific immunity to MSP3 should be considered in addition to immunity to conserved epitopes, in the development of an MSP3 malaria vaccine.     

Differential Contribution of ASPECTS Regions to Clinical Outcome after Thrombectomy for Acute Ischemic Stroke

BACKGROUND AND PURPOSE:Ischemic stroke is the leading cause of long-term disability in adults, but our ability to prognosticate from baseline imaging data is limited. The ASPECTS measures ischemic change in the middle cerebral artery territory on noncontrast CT based on 10 anatomic regions. Here, we investigated whether infarction in particular regions was associated with worse long-term outcome.MATERIALS AND METHODS:We identified consecutive patients receiving mechanical thrombectomy for ICA/MCA occlusion at 2 comprehensive stroke centers. Pretreatment ASPECTS was assessed by 2 blinded reviewers. Clinical data including demographics, baseline NIHSS score, and 90-day mRS were collected. The relationship between individual ASPECTS regions and the mRS score (0–2 versus 3–6) was assessed using multivariable logistic regression.RESULTS:Three hundred fifty-three patients were included (mean age, 70 years; 46% men), of whom 214 had poor outcome (mRS = 3–6). Caudate (OR = 3.26; 95% CI, 1.33–8.82), M4 region (OR = 2.94; 95% CI, 1.09–9.46), and insula (OR = 1.75; 95% CI, 1.08–2.85) infarcts were associated with significantly greater odds of poor outcome, whereas M1 region infarction reduced the odds of poor outcome (OR = 0.38; 95% CI, 0.14–0.99). This finding remained unchanged when restricted to only patients with good recanalization. No significant associations were found by laterality. Similarly, no region was predictive of neurologic improvement during the first 24 hours or of symptomatic intracerebral hemorrhage.CONCLUSIONS:Our results indicate that ASPECTS regions are not equal in their contribution to functional outcome. This finding suggests that patient selection based on total ASPECTS alone might be insufficient, and infarct topography should be considered when deciding eligibility for thrombectomy.

Recent advances in the field of endovascular thrombectomy have led to a sea change in the management of large-vessel-occlusion acute ischemic stroke, with several initial trials showing benefit with new-generation endovascular approaches.^1-6 The time window for thrombectomy has subsequently expanded to up to 24 hours from onset.^7,8 In all these trials, imaging was crucial to identify patients likely to benefit. Most trials in 2015 used lesion size on CT as part of their selection criteria, quantified as the ASPECTS. ASPECTS was first described in 2000 and separates the middle cerebral artery territory into 10 regions (6 superficial, 4 deep; Figure). These are then assigned a value of 0 if there are early ischemic changes—parenchymal hypoattenuation, loss of gray-white differentiation, and focal swelling—and a value of 2 if the region is normal in appearance.⁹ Correspondingly, lower scores imply more extensive ischemia and intuitively suggest that the outcome is more likely to be poor; indeed, the ASPECTS is known to have value in long-term prognostication after stroke,¹⁰ and has previously been shown to correlate with functional independence in intra-arterial thrombolysis.¹¹ Thus, low ASPECTS values continue to be used as an exclusion criterion for thrombectomy because these patients are assumed to have a low likelihood of meaningful improvement.Open in a separate windowFIGURE.Illustration of ASPECTS, showing 10 regions in 1 hemisphere. C indicates caudate; IC, internal capsule; L, lentiform; I, insula. Reproduced from Neuhaus et al²⁵ with permission from BMJ Publishing Group Ltd.However, there are a number of disadvantages in using ASPECTS. First, although it significantly correlates with long-term function on a group level, individual outcomes are discriminated less accurately, particularly when the ASPECTS is moderate to high (eg, 6–10, implying limited ischemic change).¹² Second, it is known that involvement of specific regions leads to particular functional deficits, eg, the angular gyrus in language¹³ and multiple cortical and subcortical areas in motor function.¹⁴ The ASPECTS treats all 10 areas equally; therefore, a composite ASPECTS of 7 may reflect very different lesion patterns, and there is no a priori reason to think these would be equivalent in terms of functional consequences. Third, the volumes of ASPECTS regions are not equal, and the loss of a single point can reflect a wide range of ischemic volumes, depending on which areas are affected. Indeed, it has been previously reported that some regions confer a greater risk of poor long-term outcome.¹⁵ Variation in outcome based on the affected area has also been described with ASPECTS regions from baseline CT,^15-18 though with inconsistent findings.The implication of this finding is that a significant number of patients with a poor composite ASPECTS might, in fact, have a greater likelihood of good outcome than the total score would suggest, which may influence treatment decisions. In this study, we sought to estimate regional contributions to long-term function using pretreatment ASPECTS data in a thrombectomy cohort.