Endothelial cell protection by dextran sulfate: a novel strategy to prevent acute vascular rejection in xenotransplantation

We showed recently that low molecular weight dextran sulfate (DXS) acts as an endothelial cell (EC) protectant and prevents human complement- and NK cell-mediated cytotoxicity towards porcine cells in vitro. We therefore hypothesized that DXS, combined with cyclosporine A (CyA), could prevent acute vascular rejection (AVR) in the hamster-to-rat cardiac xenotransplantation model. Untreated, CyA-only, and DXS-only treated rats rejected their grafts within 4-5 days. Of the hearts grafted into rats receiving DXS in combination with CyA, 28% survived more than 30 days. Deposition of anti-hamster antibodies and complement was detected in long-term surviving grafts. Combined with the expression of hemoxygenase 1 (HO-1) on graft EC, these results indicate that accommodation had occurred. Complement activity was normal in rat sera after DXS injection, and while systemic inhibition of the coagulation cascade was observed 1 h after DXS injection, it was absent after 24 h. Moreover, using a fluorescein-labeled DXS (DXS-Fluo) injected 1 day after surgery, we observed a specific binding of DXS-Fluo to the xenograft endothelium. In conclusion, we show here that DXS + CyA induces long-term xenograft survival and we provide evidence that DXS might act as a local EC protectant also in vivo.

Antigens of the type-three secretion system of Aeromonas salmonicida subsp. salmonicida prevent protective immunity in rainbow trout

Aeromonas salmonicida subsp. salmonicida is the etiologic agent of furunculosis, a frequent and significant disease of fisheries worldwide. The disease is largely controlled by commercial oil adjuvanted vaccines containing bacterins. However, the mechanisms leading to a protective immune response remain poorly understood. The type-three secretion system (T3SS) plays a central role in virulence of A. salmonicida subsp. salmonicida and thus may have an influence on the immune response of the host. The aim of this study was to evaluate the role of the T3SS antigens in mounting a protective immune response against furunculosis. Rainbow trout were intraperitoneally vaccinated in two independent experiments with bacterins prepared from a wild-type A. salmonicida strain and an isogenic strain carrying a deletion in the T3SS (ΔascV). Fish were challenged with the wt strain eight weeks after vaccination. In both trials, the survival rate of trout vaccinated with the ΔascV strain was significantly higher (23-28%) in comparison to the group vaccinated with the wt strain. High-throughput proteomics analysis of whole bacteria showed the ascV deletion in the mutant strain resulted in lower expression of all the components of the T3SS, several of which have a potential immunosuppressive activity. In a third experiment, fish were vaccinated with recombinant AcrV (homologous to the protective antigen LcrV of Yersinia) or S-layer protein VapA (control). AcrV vaccinated fish were not protected against a challenge while fish vaccinated with VapA were partially protected. The presence of T3SS proteins in the vaccine preparations decreased the level of protection against A. salmonicida infection and that AcrV was not a protective antigen. These results challenge the hypothesis that mounting specific antibodies against T3SS proteins should bring better protection to fish and demonstrate that further investigations are needed to better understand the mechanisms underlying effective immune responses against A. salmonicida infection.

Antibodies trap tissue migrating helminth larvae and prevent tissue damage by driving IL-4Rα-independent alternative differentiation of macrophages

Approximately one-third of the world's population suffers from chronic helminth infections with no effective vaccines currently available. Antibodies and alternatively activated macrophages (AAM) form crucial components of protective immunity against challenge infections with intestinal helminths. However, the mechanisms by which antibodies target these large multi-cellular parasites remain obscure. Alternative activation of macrophages during helminth infection has been linked to signaling through the IL-4 receptor alpha chain (IL-4Rα), but the potential effects of antibodies on macrophage differentiation have not been explored. We demonstrate that helminth-specific antibodies induce the rapid trapping of tissue migrating helminth larvae and prevent tissue necrosis following challenge infection with the natural murine parasite Heligmosomoides polygyrus bakeri (Hp). Mice lacking antibodies (JH (-/-)) or activating Fc receptors (FcRγ(-/-)) harbored highly motile larvae, developed extensive tissue damage and accumulated less Arginase-1 expressing macrophages around the larvae. Moreover, Hp-specific antibodies induced FcRγ- and complement-dependent adherence of macrophages to larvae in vitro, resulting in complete larval immobilization. Antibodies together with helminth larvae reprogrammed macrophages to express wound-healing associated genes, including Arginase-1, and the Arginase-1 product L-ornithine directly impaired larval motility. Antibody-induced expression of Arginase-1 in vitro and in vivo occurred independently of IL-4Rα signaling. In summary, we present a novel IL-4Rα-independent mechanism of alternative macrophage activation that is antibody-dependent and which both mediates anti-helminth immunity and prevents tissue disruption caused by migrating larvae.

Prioritizing Healthy Child Development Could Prevent Child Prostitution

The CHILDREN AT RISK documentaries “Domestic Minor Sex Trafficking” and “International Human Trafficking” draw attention to the dire consequences of our failure as a society to ensure that all children are raised with healthy experiences in safe and loving environments. It is our collective responsibility to put policies and services into place to prevent child prostitution from happening in the first place, while also providing treatment and care for the victims of prostitution. We must embed the prevention of child prostitution into a broader vision for healthy child development and encourage our national, state, and local policymakers to prioritize the development and implementation of a comprehensive and coordinated strategy for children.

Does Immediate Access to Birth Control Help Prevent Pregnancy? A Comparison of Onsite Provision Versus Off Campus Referral for Contraception at Two School-Based Clinics

PURPOSE: The purpose of this study was to assess the impact of different policies on access to hormonal contraception and pregnancy rates at two high school-based clinics. METHODS: Two clinics in high schools (Schools A and B), located in a large urban district in the southwest US, provide primary medical care to enrolled students with parental consent; the majority of whom have no health insurance coverage. The hormonal contraceptive dispensing policy of at School clinic A involves providing barrier, hormonal and emergency contraceptive services on site. School clinic B uses a referral policy that directs students to obtain contraception at an off-campus affiliated family planning clinic. Baseline data (age, race and history of prior pregnancy) on female students seeking hormonal contraception at the two clinics between 9/2008-12/2009 were extracted from an electronic administrative database (AHLERS Integrated System). Data on birth control use and pregnancy tests for each student was then tracked electronically through 3/31/2010. The outcomes measures were accessing hormonal contraception and positive pregnancy tests at any point during or after birth control use were started through 12/2009. The appointment keeping rate for contraceptive services and the overall pregnancy rates were compared between the two schools. In addition the pregnancy rates were compared between the two schools for students with and without a prior history of pregnancy. RESULTS: School clinic A: 79 students sought hormonal contraception; mean age 17.5 years; 68% were > 18 years; 77% were Hispanic; and 20% reported prior pregnancy. The mean duration of the observation period was 13 months (4-19 months). All 79 students received hormonal contraception (65% pill and 35% long acting progestin injection) onsite. During the observation period, the overall pregnancy rate was 6% (5/79); 4.7% (3/63) among students with no prior pregnancy. School clinic B: 40 students sought hormonal contraception; mean age 17.5 years; 52% > 18 years; 88 % were Hispanic; and 7.5% reported prior pregnancy. All 40 students were referred to the affiliated clinic. The mean duration of the observation period was 11.9 months (4-19 months). 50% (20) kept their appointment. Pills were dispensed to 85% (17/20) and 15% (3/20) received long acting progestin injection. The overall pregnancy rate was 20% (8/40); 21.6% (8/37) among students with no prior pregnancy. A significantly higher frequency of students seeking hormonal contraception kept their initial appointment for birth control at the school dispensing onsite contraception compared to the school with a referral policy for contraception (p<0.05). The pregnancy rate was significantly higher for the school with a referral policy for contraception compared to the school with onsite contraceptive services (p< 0.05). The pregnancy rate was also significantly higher for students without a prior history of pregnancy in the school with a referral policy for contraception (21.6%) versus the school with onsite contraceptive services (4.7%) (p< 0.05). CONCLUSION: This preliminary study showed that School clinic B with a referral policy had a lower appointment keeping rate for contraceptive services and a higher pregnancy rate than School clinic A with on-site contraceptive services. An on-site dispensing policy for hormonal contraceptives at high school-based health clinics may be a convenient and effective approach to prevent unintended first and repeat pregnancies among adolescents who seek hormonal contraception. This study has strong implications for reproductive health policy, especially as directed toward high-risk teenage populations.

Introduction to “A Compendium of Strategies to Prevent Healthcare-Associated Infections in Acute Care Hospitals: 2014 Updates”

Abstract Since the publication of "A Compendium of Strategies to Prevent Healthcare-Associated Infections in Acute Care Hospitals" in 2008, prevention of healthcare-associated infections (HAIs) has become a national priority. Despite improvements, preventable HAIs continue to occur. The 2014 updates to the Compendium were created to provide acute care hospitals with up-to-date, practical, expert guidance to assist in prioritizing and implementing their HAI prevention efforts. It is the product of a highly collaborative effort led by the Society for Healthcare Epidemiology of America (SHEA), the Infectious Diseases Society of America (IDSA), the American Hospital Association (AHA), the Association for Professionals in Infection Control and Epidemiology (APIC), and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise, including the Centers for Disease Control and Prevention (CDC), the Institute for Healthcare Improvement (IHI), the Pediatric Infectious Diseases Society (PIDS), the Society for Critical Care Medicine (SCCM), the Society for Hospital Medicine (SHM), and the Surgical Infection Society (SIS).

Can non-selective beta-blockers prevent hepatocellular carcinoma in patients with cirrhosis?

Hepatocellular carcinoma is the main liver-related cause of death in patients with compensated cirrhosis. The early phases are asymptomatic and the prognosis is poor, which makes prevention essential. We propose that non-selective beta-blockers decrease the incidence and growth of hepatocellular carcinoma via a reduction of the inflammatory load from the gut to the liver and inhibition of angiogenesis. Due to their effect on the portal pressure, non-selective beta-blockers are used for prevention of esophageal variceal bleeding. Recently, non-hemodynamic effects of beta-blockers have received increasing attention. Blockage of β-adrenoceptors in the intestinal mucosa and gut lymphatic tissue together with changes in type and virulence of the intestinal microbiota lead to reduced bacterial translocation and a subsequent decrease in the portal load of pathogen-associated molecular patterns. This may reduce hepatic inflammation. Blockage of β-adrenoceptors also decrease angiogenesis by inhibition of vascular endothelial growth factors. Because gut-derived inflammation and neo-angiogenesis are important in hepatic carcinogenesis, non-selective beta-blockers can potentially reduce the development and growth of hepatocellular carcinoma. Rodent and in vitro studies support the hypothesis, but clinical verification is needed. Different study designs may be considered. The feasibility of a randomized controlled trial is limited due to the necessary large number of patients and long follow-up. Observational studies carry a high risk of bias. The meta-analytic approach may be used if the incidence and mortality of hepatocellular carcinoma can be extracted from trials on variceal bleeding and if the combined sample size and follow up is sufficient.

Comparative effectiveness of long term drug treatment strategies to prevent asthma exacerbations: network meta-analysis

Objective To determine the comparative effectiveness and safety of current maintenance strategies in preventing exacerbations of asthma. Design Systematic review and network meta-analysis using Bayesian statistics. Data sources Cochrane systematic reviews on chronic asthma, complemented by an updated search when appropriate. Eligibility criteria Trials of adults with asthma randomised to maintenance treatments of at least 24 weeks duration and that reported on asthma exacerbations in full text. Low dose inhaled corticosteroid treatment was the comparator strategy. The primary effectiveness outcome was the rate of severe exacerbations. The secondary outcome was the composite of moderate or severe exacerbations. The rate of withdrawal was analysed as a safety outcome. Results 64 trials with 59 622 patient years of follow-up comparing 15 strategies and placebo were included. For prevention of severe exacerbations, combined inhaled corticosteroids and long acting β agonists as maintenance and reliever treatment and combined inhaled corticosteroids and long acting β agonists in a fixed daily dose performed equally well and were ranked first for effectiveness. The rate ratios compared with low dose inhaled corticosteroids were 0.44 (95% credible interval 0.29 to 0.66) and 0.51 (0.35 to 0.77), respectively. Other combined strategies were not superior to inhaled corticosteroids and all single drug treatments were inferior to single low dose inhaled corticosteroids. Safety was best for conventional best (guideline based) practice and combined maintenance and reliever therapy. Conclusions Strategies with combined inhaled corticosteroids and long acting β agonists are most effective and safe in preventing severe exacerbations of asthma, although some heterogeneity was observed in this network meta-analysis of full text reports.

The number needed to treat to prevent mortality and cirrhosis-related complications among patients with cirrhosis and HCV genotype 1 infection

Cirrhotic patients with chronic hepatitis C virus (HCV) infection remain at risk for complications following sustained virological response (SVR). Therefore, we aimed to evaluate treatment efficacy with the number needed to treat (NNT) to prevent clinical endpoints. Mortality and cirrhosis-related morbidity were assessed in an international multicentre cohort of consecutively treated patients with HCV genotype 1 infection and cirrhosis. The NNT to prevent death or clinical disease progression (any cirrhosis-related event or death) in one patient was determined with the adjusted (event-free) survival among patients without SVR and adjusted hazard ratio of SVR. Overall, 248 patients were followed for a median of 8.3 (IQR 6.2-11.1) years. Fifty-nine (24%) patients attained SVR. Among patients without SVR, the adjusted 5-year survival and event-free survival were 94.4% and 80.0%, respectively. SVR was associated with reduced all-cause mortality (HR 0.15, 95% CI 0.05-0.48, P = 0.002) and clinical disease progression (HR 0.16, 95% CI 0.07-0.36, P < 0.001). The NNT to prevent one death in 5 years declined from 1052 (95% CI 937-1755) at 2% SVR (interferon monotherapy) to 61 (95% CI 54-101) at 35% SVR (peginterferon and ribavirin). At 50% SVR, which might be expected with triple therapy, the estimated NNT was 43 (95% CI 38-71). The NNT to prevent clinical disease progression in one patient in 5 years was 302 (95% CI 271-407), 18 (95% CI 16-24) and 13 (95% CI 11-17) at 2%, 35% and 50% SVR, respectively. In conclusion, the NNT to prevent clinical endpoints among cirrhotic patients with HCV genotype 1 has declined enormously with the improvement of antiviral therapy.

A compendium of strategies to prevent healthcare-associated infections in acute care hospitals: 2014 updates

Since the publication of "A Compendium of Strategies to Prevent Healthcare-Associated Infections in Acute Care Hospitals" in 2008, prevention of healthcare-associated infections (HAIs) has become a national priority. Despite improvements, preventable HAIs continue to occur. The 2014 updates to the Compendium were created to provide acute care hospitals with up-to-date, practical, expert guidance to assist in prioritizing and implementing their HAI prevention efforts. They are the product of a highly collaborative effort led by the Society for Healthcare Epidemiology of America (SHEA), the Infectious Diseases Society of America (IDSA), the American Hospital Association (AHA), the Association for Professionals in Infection Control and Epidemiology (APIC), and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise, including the Centers for Disease Control and Prevention (CDC), the Institute for Healthcare Improvement (IHI), the Pediatric Infectious Diseases Society (PIDS), the Society for Critical Care Medicine (SCCM), the Society for Hospital Medicine (SHM), and the Surgical Infection Society (SIS).