Advances in medical revascularisation treatments in acute ischemic stroke

Urgent reperfusion of the ischaemic brain is the aim of stroke treatment and there has been ongoing research to find a drug that can promote vessel recanalisation more completely and with less side effects. In this review article, the major studies which have validated the use and safety of tPA are discussed. The safety and efficacy of other thrombolytic and anticoagulative agents such as tenecteplase, desmoteplase, ancrod, tirofiban, abciximab, eptifibatide, and argatroban are also reviewed. Tenecteplase and desmoteplase are both plasminogen activators with higher fibrin affinity and longer half-life compared to alteplase. They have shown greater reperfusion rates and improved functional outcomes in preliminary studies. Argatroban is a direct thrombin inhibitor used as an adjunct to intravenous tPA and showed higher rates of complete recanalisation in the ARTTS study with further studies which are now ongoing. Adjuvant thrombolysis techniques using transcranial ultrasound are also being investigated and have shown higher rates of complete recanalisation, for example, in the CLOTBUST study. Overall, development in medical therapies for stroke is important due to the ease of administration compared to endovascular treatments, and the new treatments such as tenecteplase, desmoteplase, and adjuvant sonothrombolysis are showing promising results and await further large-scale clinical trials.

Ischemia-reperfusion injury in an aortic dissection patient

Aortic dissection is a life-threatening emergency. Well-established risk factors include systemic hypertension, hereditary connective tissue diseases (Marfan syndrome and Ehlers-Danlos syndrome), coarctation of the aorta, bicuspid aortic valve, aortitis, and arch hypoplasia. Ischemia of the viscera, the kidneys, the spinal cord, or the lower extremities due to malperfusion constitutes life-threatening complications that have to be considered in the treatment strategy.We report a rare case of symptomatic ischemia of the lower extremities due to aortic dissection. This case demonstrates that the treating physician needs to be vigilant for ischemia reperfusion injuries such as osteofascial compartment syndrome and acute renal failure in aortic dissection.

[Antibody persistence following booster vaccination with three doses of hepatitis B vaccines among low-response adults in Zhangqiu county of Shandong province: 24-month of follow-up from 2009]

OBJECTIVE

To assess the 24-month efficacy after booster vaccination with 3 doses of hepatitis B vaccine among low-response adults in Zhangqiu county of Shandong province.

METHODS

A total of 24 237 adults aged 18-49 years old, never received HepB vaccination, without HBV infection history, and had been living at 3 towns of Zhangqiu county in Shandong province for more than half a year in september, 2009, were collected blood samples of 3-5 ml. A total of 11 590 adults who were negative for hepatitis B virus (HBV) surface antigen (HBsAg) , antibody to HBsAg (Anti-HBs) and antibody to HBV core antigen (Anti-HBc), were divided into four groups randomly and were vaccinated following the schedule of 0-1-6 with 20 µg hepatitis B vaccine made by recombinant deoxyribonucleic acid techniques in Saccharomyces cerevisiae (HepB-SC), 20 µg hepatitis B vaccine made by Chinese hamster ovary cell (HepB-CHO), 10 µg HepB-SC and 10 µg hepatitis B vaccine made by recombinant deoxyribonucleic acid techniques in Hansenula Polymorpha (HepB-HP), respectively. The adults who were low-response to the primary hepatitis B vaccination (10 mU/ml ≤ anti-HBs<100 mU/ml) were divided into four groups by cluster random sampling. These groups were revaccinated with 3-dose of above-mentioned four kinds of HepB respectively. Blood samples were drawn from 1 month (T1) and 24 month (T24) after the 3 dose revaccination, respectively. Anti-HBs and anti-HBc was detected by Chemiluminescence Microparticle Imunoassay (CMIA).

RESULTS

Out of the 8 592 adults who have accepted the primary vaccination of hepatitis B and been collected the blood samples, 1 306 subjects showed low-response. A total of 718 low-response subjects were collected blood samples after T1 and T24 following 3 doses of booster vaccination. The proportion of the four groups was 32.3% (232/718), 25.8% (185/718) , 19.3% (139/718) , 22.6% (162/718) , respectively. The average proportion of anti-HBs ≥ 100 mIU/ml were decreased from 77.58% after T1 to 35.63% after T24 (χ² = 256.87, P < 0.01). The proportion of anti-HBs ≥ 100 mIU/ml in T24 were 38.8% (90/177), 39.5% (73/185), 25.2% (35/139) and 35.8% (58/162) in four groups, respectively. The proportion of anti-HBs>100 mIU/ml in T24 was significantly different among groups (χ² = 8.81, P = 0.032). The average geometric mean concentration (GMC) was significantly reduced from 443.53 mIU/ml after T1 to 48.98 mIU/ml after T24 (F = 439.41, P < 0.01). The GMC was 60.26 (45.71-77.62), 1.29 (38.90-69.18) , 35.48 (25.70-48.98) and 46.77 (33.88-6.07) mIU/ml in four groups, respectively (F = 1.97, P = 0.117) . Compared with vaccinated 20 µg HepB-SC, the proportion of anti-HBs ≥ 100 mIU/ml and GMC was 0.56 (0.35-0.91) and -0.20 (-0.39--0.02) times. The positive of HBsAg was not found and the positive rate of anti-HBc was 2.6% (18/692) in T24.

CONCLUSION

Protective antibody following booster vaccination with three doses of hepatitis B vaccines among low-response adults after 2 years fade faster. Antibody level of anti-HBs in T24 was corrected with the booster vaccine type and age. 20 µgHepB-SC seemed better than 10 µg HepB-SC.

Perinatal hepatitis B prevention program in Shandong Province, China. Evaluation and progress

Post-exposure prophylaxis with hepatitis B vaccine (HepB) alone is highly effective in preventing perinatal hepatitis B virus (HBV) transmission and the World Health Organization recommends administering HepB to all infants within 24 h after delivery. Maternal screening for HBsAg and administration of hepatitis B immune globulin (HBIG) in addition to HepB for infants born to HBsAg-positive pregnant women can increase the effectiveness of post-exposure prophylaxis for perinatal HBV transmission. In Shangdong Province, China which has a high prevalence of chronic HBV infection, HepB birth dose and HBIG were integrated into the routine childhood immunization program in 2002 and July 2011 respectively. We assessed progress toward implementation of these measures. Hospital-based reporting demonstrated an increase in maternal screening from 70.7% to 96.9% from 2004-2012; HepB birth dose coverage (within 24 h) remained high (96.3-97.1%) during this period. For infants with known HBsAg-positive mothers, the coverage of HBIG increased from 85.0% (before July 2011) to 92.1% (after July 2011). However, HBIG coverage in western areas of Shandong Province remained at 81.1% among infants with known HBsAg-positive mothers. Preterm/low-birth-weight and illness after birth were the most commonly reported reasons for delay in the first dose of HepB to >24 h of birth. Additional education on the safety and immune protection from HepB and HBIG might help to correct delays in administering the HepB birth dose and low HBIG coverage in the western areas of the Shandong Province.

A new subtype of crossed fused ectopia of the kidneys

Crossed fused renal ectopia is a rare congenital anomaly; here, we report a new subtype of crossed fused renal ectopia associated with the retroiliac megaureter and thoracic scoliosis deformity. It is beyond the traditional classification of crossed fused renal ectopia. There are 2 kidneys in the left and hydronephrosis of the upper kidney, the right kidney crossed over and fused with the lower kidney of the left. It is never seen in previous reports. Recurrent infection was cured by resecting the hydronephrosis of the upper kidney and retroiliac megaureter.

[Matching study on immune response between single anti-HBc positivity and healthy adults after primary immunization and revaccination of hepatitis B vaccine]

OBJECTIVE

To compare the antibody response between adults with hepatitis B virus (HBV) core antibody (anti-HBc) single positivity and healthy adults after primary immunization and revaccination of hepatitis B vaccine(HepB).

METHODS

Adults aged from 18 to 49 who were both negative for HBV surface antigen (HBsAg) and antibody to HBsAg (anti-HBs), but positive for anti-HBc and narrated no history of HepB immunization by themselves, were selected as single anti-HBc positive group ('anti-HBc alone'). Adults who were negative for HBsAg, anti-HBs and anti-HBc, with age differences within 2 years, and same gender under the 1 : 1 matching program, were selected to form the control group. Both groups were vaccinated on 0-1-6 schedule with the same HepB. Those who were non-response to HepB at primary immunization were revaccination on 0-1-6 schedule. Response rates and geometric mean concentrations (GMC) between the two groups were compared.

RESULTS

In total, the number of anticipants were 228 pairs. Rates on non-response, low-response, normal-response and high-response after the primary immunization were 8.77% , 11.84%, 31.14% and 48.25% in the control group respectively. The corresponding rates were 8.33%, 30.70%, 35.96% and 25.00% in the 'anti-HBc alone'. The rate of low-response in the control group was lower than that in the 'anti-HBc alone' (χ(2) = 22.28, P < 0.01), while the rate of high-response was higher than that in the control group (χ(2) = 24.43, P < 0.01). GMC of anti-HBs in the control group (534.07 mIU/ml) was higher than that in the 'anti-HBc alone' (183.99 mIU/ml) (u = 4.42, P < 0.01). The anti-HBs conversion rates were 82.35% and 41.18% in the control group and in the 'anti-HBc alone' respectively after the first-dose revaccination, but increased to 90.00% and 82.35% after the third-dose revaccination. The anti-HBs conversion rates in the control group were higher than that in the 'anti-HBc alone' after the first-dose revaccination (P < 0.05), while there was no difference seen between the two groups after the third-dose revaccination (P > 0.05).

CONCLUSION

Immune response in the anti-HBc positive adults after primary immunization was weaker than that in common adults. However, immune response induced by HepB was enough to prevent them from infecting HBV. The rates of response showed an obvious increase after revaccination, hence the same HepB immunization strategy could be used.

Bosentan protects the spinal cord from ischemia reperfusion injury in rats through vascular endothelial growth factor receptors

STUDY DESIGN

Experimental study.

OBJECTIVES

To investigate whether Bosentan, an endothelin-A/-B dual receptor antagonist, could protect neurons after spinal cord ischemia reperfusion (SCIR) injury in rats and its underlying signaling pathway.

SETTING

Department of Neurosurgery, the Second Affiliated Hospital, Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi Province, China.

METHODS

Sprague-Dawley rats were randomly divided into two groups, saline group (IRS, n=48) and Bosentan group (IRB, 5 mg kg(-1), n=48). After ischemia for 1 h with occlusion of the infrarenal aorta, spinal cord were reperfused for 6h, 12h, 24h, 3d, 5d, and 7d separately. Enzyme-linked immunosorbent assay was used to detect vascular endothelial growth factor (VEGF) in serum. Immunohistochemistry was performed to detect protein expression of VEGF, VEGF receptor 1 (FLT-1) and VEGF receptor 2 (FLK-1). Gene expressions of VEGF and its receptors were evaluated using the quantitative reverse transcription polymerase chain reaction.

RESULTS

Compared with the IRS group, gene and protein expressions of VEGF, FLT-1 and FLK-1 were significantly increased (P<0.05), so was the concentration of VEGF in plasma (P<0.05). FLK-1 was expressed on spinal cord neurons.

Minimising time to treatment: targeted strategies to minimise time to thrombolysis for acute ischaemic stroke

Time to thrombolysis is a critical determinant of favourable outcomes in acute ischaemic stroke. It is not infrequent that patient outcomes are compromised due to out-of-hospital and in-hospital time delays. On the other hand, time delays could be minimised through the identification of barriers and the implementation of targeted solutions. This review outlines the different strategies in minimising treatment delays and offers recommendations. Literature search in PubMed, Medline and EBSCO Host was conducted to identify studies that are relevant to reduction of time to treatment from January 1995 to December 2012. Strategies to reduce time to thrombolysis are categorised into pre-hospital strategies, in-hospital strategies and post-treatment decision strategies. Proposed pre-hospital strategies include public education on stroke symptoms awareness, prioritising stroke by emergency medical services, increasing ease of access to medical records, pre-hospital notification, and mobile computed tomography scanning. In-hospital strategies include a streamlined code stroke system, computed tomography scanner co-location with emergency department, 24/7 availability of stroke physicians, point-of-care laboratory testing and access to expert neuroimaging interpretation. Post-decision strategies include increasing availability of intravenous thrombolysis and simplification of informed consent procurement. Time to thrombolysis delays is multifactorial. Effective reduction of time delays for acute ischaemic stroke requires the correct identification of and targeted strategies to overcome time barriers.

Chromosome 12p13 variants predict recurrence of ischaemic stroke in a Chinese population

BACKGROUND AND PURPOSE

A recent genome-wide association study identified two genetic variants (rs12425791 and rs11833579) on chromosome 12p13 that confer risk of ischaemic stroke. The purpose of this study was to examine whether these two polymorphisms are associated with stroke onset and prognosis in a Chinese population.

METHODS

rs12425791 and rs11833579 were genotyped using the improved multiple ligase detection reaction in 913 patients with ischaemic stroke. Analyses of genotype association with onset and prognosis outcomes were evaluated by the Kaplan-Meier method, the log-rank test and Cox proportional hazards models.

RESULTS

rs12425791 and rs11833579 were not associated with age of stroke onset (P = 0.786 and 0.340, respectively). However, these two polymorphisms were significantly associated with risk of stroke recurrence, especially for the large-artery atherosclerosis (LAA) subtype, in recessive models [hazard ratio (HR) 2.52; 95% confidence interval (CI) 1.04-6.12 for rs12425791; HR 2.13; 95% CI 1.03-4.40 for rs11833579]. The combined genotype of these two single-nucleotide polymorphisms showed a locus-dosage effect on recurrence of LAA subtype and was an independent prognostic factor for LAA subtype in the final multivariate Cox regression model.

CONCLUSIONS

These findings indicated that rs12425791 and rs11833579 on chromosome 12p13 may be useful biomarkers for predicting the prognosis of patients with the LAA subtype of ischaemic stroke.

Relative filling time delay based on CT perfusion source imaging: a simple method to predict outcome in acute ischemic stroke

BACKGROUND AND PURPOSE

Collateral vessel status is strongly associated with clinical outcome in ischemic stroke but can be challenging to assess. The aim of this study was to develop a tomography perfusion source imaging-based assessment of collateral vessel status.

MATERIALS AND METHODS

Consecutive patients with ischemic stroke who received intravenous thrombolysis or intra-arterial reperfusion therapy after CTP were retrospectively analyzed. In those with middle cerebral artery or internal carotid artery occlusion, CT perfusion source imaging was used to identify the relative filling time delay between the normal MCA Sylvian branches and those in the affected hemisphere. Receiver operating characteristic analysis and logistic regression were used to assess the association of the relative filling time delay with the 24-hour Alberta Stroke Program Early CT Score based on noncontrast CT and the 90-day modified Rankin Scale score.

RESULTS

There were 217 patients treated in 2009-2011 who had CTP data, of whom 60 had MCA or ICA occlusion and 55 had 90-day mRS data. The intraclass correlation coefficient for relative filling time delay was 0.95. Relative filling time delay was correlated with 24-hour ASPECTS (Spearman ρ=-0.674; P<.001) and 90-day mRS score (ρ=0.516, P<.01). Increased relative filling time delay was associated with poor radiologic outcome (ASPECTS, 0-7) (area under the curve=0.79, P<.001) and poor functional outcome (mRS score, 3-6) (area under the curve=0.77, P=.001). In multivariate logistic regression, the association of longer relative filling time delay with poor outcome remained significant, independent of age, sex, and baseline National Institutes of Health Stroke Scale score.

CONCLUSIONS

Relative filling time delay is a useful independent predictor of clinical outcome after ischemic stroke.

The impact of arterial collateralization on outcome after intra-arterial therapy for acute ischemic stroke

BACKGROUND AND PURPOSE

Although intra-arterial therapy for acute ischemic stroke is associated with superior recanalization rates, improved clinical outcomes are inconsistently observed following successful recanalization. There is emerging concern that unfavorable arterial collateralization, though unproven, predetermines poor outcome. We hypothesized that poor leptomeningeal collateralization, assessed by preprocedural CTA, is associated with poor outcome in patients with acute ischemic stroke undergoing intra-arterial therapy.

MATERIALS AND METHODS

We retrospectively analyzed patients with acute ischemic stroke with intracranial ICA and/or MCA occlusions who received intra-arterial therapy. The collaterals were graded on CTA. Univariate and multivariate analyses were used to investigate the association between the dichotomized leptomeningeal collateral score and functional outcomes at 3-months mRS ≤2, mortality, and intracranial hemorrhages.

RESULTS

Eighty-seven patients were included. The median age was 66 years (interquartile range, 54-76 years) and the median NIHSS score at admission was 18 (interquartile range, 14-20). The leptomeningeal collateral score 3 was found to have significant association with the good functional outcome at 3 months: OR = 3.13; 95% CI, 1.25-7.825; P = .016. This association remained significant when adjusted for the use of IV tissue plasminogen activator: alone, OR = 2.998; 95% CI, 1.154-7.786; P = .024; and for IV tissue plasminogen activator and other confounders (age, baseline NIHSS score, and Thrombolysis in Cerebral Infarction grades), OR = 2.985; 95% CI, 1.027-8.673; P = .045.

CONCLUSIONS

We found that poor arterial collateralization, defined as a collateral score of <3, was associated with poor outcome, after adjustment for recanalization success. We recommend that future studies include collateral scores as one of the predictors of functional outcome.

Modelling and predicting the biological effects of nanomaterials

The commercial applications of nanoparticles are growing rapidly, but we know relatively little about how nanoparticles interact with biological systems. Their value--but also their risk--is related to their nanophase properties being markedly different to those of the same material in bulk. Experiments to determine how nanoparticles are taken up, distributed, modified, and elicit any adverse effects are essential. However, cost and time considerations mean that predictive models would also be extremely valuable, particularly assisting regulators to minimize health and environmental risks. We used novel sparse machine learning methods that employ Bayesian neural networks to model three nanoparticle data sets using both linear and nonlinear machine learning methods. The first data comprised iron oxide nanoparticles decorated with 108 different molecules tested against five cell lines, HUVEC, pancreatic cancer, and three macrophage or macrophage-like lines. The second data set comprised 52 nanoparticles with various core compositions, coatings, and surface attachments. The nanoparticles were characterized using four descriptors (size, relaxivities, and zeta potential), and their biological effects on four cells lines assessed using four biological assays per cell line and four concentrations per assay. The third data set involved the biological responses to gold nanoparticles functionalized by 80 different small molecules. Nonspecific binding and binding to AChE were the biological endpoints modelled. The biological effects of nanoparticles were modelled using molecular descriptors for the molecules that decorated the nanoparticle surface. Models with good statistical quality were constructed for most biological endpoints. These proof-of-concept models show that modelling biological effects of nanomaterials is possible using modern modelling methods.

Suppressing the loss of ultracold molecules via the continuous quantum Zeno effect

We investigate theoretically the suppression of two-body losses when the on-site loss rate is larger than all other energy scales in a lattice. This work quantitatively explains the recently observed suppression of chemical reactions between two rotational states of fermionic KRb molecules confined in one-dimensional tubes with a weak lattice along the tubes [Yan et al., Nature (London) 501, 521 (2013)]. New loss rate measurements performed for different lattice parameters but under controlled initial conditions allow us to show that the loss suppression is a consequence of the combined effects of lattice confinement and the continuous quantum Zeno effect. A key finding, relevant for generic strongly reactive systems, is that while a single-band theory can qualitatively describe the data, a quantitative analysis must include multiband effects. Accounting for these effects reduces the inferred molecule filling fraction by a factor of 5. A rate equation can describe much of the data, but to properly reproduce the loss dynamics with a fixed fillingfraction for all lattice parameters we develop a mean-field model and benchmark it with numerically exacttime-dependent density matrix renormalization group calculations.

Ultrasmall and monodisperse colloidal amorphous Nd–Fe–B–Na magnetic nanoparticles with high TC

Ultrasmall and monodisperse air-stable colloidal Nd–Fe–B nanoparticles have been synthesized by the solution phase colloidal method and characterized by TEM and SQUID. Their size can be controlled in the sub-5 nm regime. The critical temperature (T_C) of Nd–Fe–B nanoparticles with 3 nm diameter is surprisingly high, higher than 650 K.

Novel photofunctional hybrid materials (alumina and titania) functionalized with both MOF and lanthanide complexes through coordination bonds

Multi-component sol–gel derived alumina and titania hybrid materials are assembled by the functionalization of both lanthanide complexes and a special metal organic framework compound: Al-MIL-53-COOH through coordination bonds. Multi-color luminescence and white colored light can be tuned by controlling the different units in the hybrid system.

Genetic analysis of the TBX2 gene promoter in indirect inguinal hernia

PURPOSE

Inguinal hernia is a common disease, majority of which are indirect inguinal hernia (IIH). A positive family history indicates that genetic factors play important roles in the IIH development. To date, genetic causes for IIH remain unknown. T-box transcription factor 2 (TBX2) is a major regulator in the morphogenesis and organogenesis. The human TBX2 gene is widely expressed in fetal and adult tissues, including muscle and connective tissues. Therefore, we speculated that altered TBX2 gene expression may be involved in the IIH formation.

METHODS

IIH patients (n = 129) and ethnic-matched healthy subjects (n = 198) were recruited for this study. The human TBX2 gene promoters were generated with PCR and directly sequenced to identify DNA sequence variants (DSVs). Furthermore, biological functions of the DSVs were examined with reporter gene constructs in cultured cells.

RESULTS

Total six DSVs within the TBX2 gene promoter were identified. A heterozygous DSV (g.59476307G>C) was identified in an IIH patient, but in none of controls, which significantly decreased the TBX2 gene promoter activities. Another heterozygous DSV (g.59476704G>C) was only found in one control, which did not affect TBX2 gene promoter activities. Four DSVs, g.59476316C>A (rs73991913), g.59476415T>C (rs1476781), g.59476510G>C (rs4455026) and g.59476892C>T (rs2286524), all of which were single nucleotide polymorphisms, were found in both IIH patients and controls with similar frequencies.

CONCLUSIONS

Our data suggested that the DSV within the TBX2 gene promoter was implicated in the IIH development as a rare cause.

A genome-wide association study identifies polymorphisms in the HLA-DR region associated with non-response to hepatitis B vaccination in Chinese Han populations

Vaccination against hepatitis B virus is an effective and routine practice that can prevent infection. However, 5-10% of healthy adults fail to produce protective levels of antibody against the hepatitis B vaccination. It has been reported that host genetic variants might affect the immune response to hepatitis B vaccination. Here, we reported a genome-wide association study in a Chinese Han population consisting of 108 primary high-responders and 77 booster non-responders to hepatitis B vaccination using the Illumina HumanOmniExpress Beadchip. We identified 21 SNPs at 6p21.32 were significantly associated with non-response to booster hepatitis B vaccination (P-value <1 × 10(-6)). The most significant SNP in the region was rs477515, located ∼12 kb upstream of the HLA-DRB1 gene. Its P-value (4.81 × 10(-8)) exceeded the Bonferroni-corrected genome-wide significance threshold. Four tagging SNPs (rs477515, rs28366298, rs3763316 and rs13204672) that capture genetic information of these 21 SNPs were validated in three additional Chinese Han populations, consisting of 1336 primary high-responders and 420 primary non-responders. The four SNPs continued to show significant associations with non-response to hepatitis B vaccination (P-combined = 3.98 × 10(-13)- 1.42 × 10(-8)). Further analysis showed that the rs477515 was independently associated with non-response to hepatitis B vaccination with correction for other three SNPs in our GWAS and the known hepatitis B vaccine immunity associated SNP in previous GWAS. Our findings suggest that the rs477515 was an independent marker associated with non-response to hepatitis B vaccination and HLA-DR region might be a critical susceptibility locus of hepatitis B vaccine-induced immunity.