Clinical implications of β-lactam-aminoglycoside synergism: systematic review of randomised trials

β-Lactam-aminoglycoside combinations are commonly used despite lack of evidence of a clinical benefit. In this study, all randomised controlled trials (RCTs) assessing directly the clinical implications of synergism by comparing a β-lactam with the same β-lactam in combination with an aminoglycoside as empirical or definitive therapy for any type of infection and clinical scenario were compiled. A systematic search was undertaken to identify all trials regardless of language, date or publication status. The primary outcomes assessed were all-cause mortality and clinical failure regardless of antibiotic modifications. Risk of bias was evaluated and its effect was assessed through sensitivity analyses. Two reviewers applied inclusion criteria and extracted the data independently. A fixed-effect meta-analysis was performed. Fifty-two RCTs were identified assessing patients with febrile neutropenia, pneumonia, abdominal infections, bacteraemia, endocarditis or cystic fibrosis. Only five trials were double-blinded. All-cause mortality was similar with monotherapy versus combination therapy [risk ratio (RR)=0.96, 95% confidence interval (CI) 0.78-1.18, 28 trials, 3756 episodes]. Clinical failure regardless of antibiotic modifications was not significantly different (RR=0.88, 95% CI 0.74-1.05, 27 trials, 2500 episodes). Treatment failure including antibiotic addition/modification occurred more frequently with monotherapy (RR=1.20, 95% CI 1.12-1.28, 48 trials, 6643 episodes). There were no significant differences with regard to bacterial or fungal superinfections or development of antibiotic-resistant strains. Combination therapy resulted in a significantly higher incidence of adverse events, mainly nephrotoxicity. Overall, no clinical benefit was found for the use of a β-lactam with an aminoglycoside compared with a β-lactam alone. Treatment with β-lactams as monotherapy entailed more antibiotic regimen modifications in open trials.     

A bioactive self-assembled membrane to promote angiogenesis

We report here on a bioactive hierarchically structured membrane formed by self-assembly. The membrane is formed with hyaluronic acid and peptide amphiphiles with binding affinity for heparin, and its hierarchical structure contains both an amorphous zone and a layer of fibrils oriented perpendicular to the membrane plane. The design of bioactivity is based on the potential ability to bind and slowly release heparin-binding growth factors. Human mesenchymal stem cells (hMSCs) seeded on these membranes attached and remained viable. Basic fibroblast growth factor (FGF2) and vascular endothelial growth factor (VEGF) were incorporated within the membrane structure prior to self-assembly and released into media over a prolonged period of time (14 days). Using the chicken chorioallantoic membrane (CAM) assay, we also found that these membranes induced a significant and rapid enhancement of angiogenesis relative to controls.     

Neonatal stress modulates sickness behavior

The quality of the early environment, especially during the neonatal period, influences the development of individual differences in resistance to stress and illness in adulthood. A previous study demonstrated that neonatal stress augmented proinflammatory cytokine expression and viral replication in influenza virus-infected adult mice. The goal of the following study was to examine the lifelong effects of neonatal stress on the behavioral response to an immune challenge. Neonatal stress consisted of separating mouse pups from their dams (maternal separation, MSP) at critical points of their development. In the first study, pups were separated from the dam daily for 6 h between postnatal day 1 and 14. As adults, these mice were infected with influenza A/PR8 virus. In a second study, a similar paradigm of MSP was employed, and as adults mice were injected with lipopolysaccharide (LPS) (ip). In a third study pups were separated from the dam for 24 h on postnatal day 4 or 9. As adults, these mice received ip injections of LPS. In all three studies, changes in body weight, food and sweet solution consumption were examined following immune challenge. As previously described, activation of the immune system using influenza virus infection or LPS administration resulted in sickness behavior that consisted of body weight loss, anorexia and reduced consumption of a sweet solution. Furthermore, neonatal stress induced more rapid kinetics of sickness behavior and augmented several aspects of these symptoms. Together with previous studies, these findings suggest that neonatal stress disrupted the regulation of innate resistance to an immune challenge resulting in enhanced immunological and behavioral responses to immune activation. Thus, long lasting effects of early stress events may be the basis for individual differences in health and susceptibility to disease.     

Monotherapy of lamotrigine versus carbamazepine in patients with poststroke seizure

OBJECTIVES: The incidence of seizures is known to be high in the elderly. The most common cause of an unprovoked seizure in the elderly population is stroke. These patients require effective and well-tolerated antiepileptic treatment because they frequently experience other medical conditions and use other medications that can interact with the antiepileptic treatment. The aim of the study was to analyze the tolerability and efficacy of lamotrigine (LTG) versus sustained-release carbamazepine (CBZ) treatment in newly diagnosed symptomatic poststroke seizure. METHODS: Sixty-four patients with a first post episode of seizures were randomized in a 1:1 ratio to either LTG or CBZ treatment and were followed up prospectively for up to 12 months for efficacy and tolerability of the drugs. RESULTS: More patients in the LTG group were seizure-free (72%) versus those in the CBZ group (44%; P = 0.06), but the numbers did not reach statistical significance because of a relative small number of study patients. The number of patients who withdraw from the study because of adverse events was statistically significantly less in the LTG group (3%) compared with the CBZ group (31%; P = 0.02). CONCLUSIONS: The LTG treatment in poststroke seizures versus CBZ treatment is a relatively better-tolerated drug and can be acceptable as initial treatment in this specific group of patients.     

Effect of scanner type on the reproducibility of extracoronary measures of calcification: the multi-ethnic study of atherosclerosis

RATIONALE AND OBJECTIVES: Cardiac computed tomography (CT) has been used extensively to measure coronary artery calcification. However, extracoronary calcifications, such as aortic valve calcification (AVC), may have independent clinical significance as well. The ability to track calcification is dependent on the reproducibility of the original measurement, and the variability of extracoronary calcification measurements still is unknown. Accurate quantification of calcification of the aortic valve, mitral annulus (MAC), and thoracic aortic (TAC) may be possible by using cardiac CT. METHODS: A total of 1,729 randomly chosen participants (ages 45-84, 53% female, 28% African-American, 36% Caucasian, 11% Chinese, 25% Hispanic) of the Multi-Ethnic Study of Atherosclerosis underwent dual scanning by electron beam CT (EBT) or multidetector CT (MDCT) to assess coronary and extra-coronary calcifications. Two calcium measurement methods--Agatston score (AS) and volume score (VS)--were measured for each scan. Concordance for calcium positivity was assessed among all scans. Mean absolute and relative differences between calcium measures on scans 1 and 2, excluding cases for which both scans had a measure of zero, was modeled by using linear regression to compare variability between scanner types. A repeated measures analysis of variance test was used to compare variability across calcium measures, with mean percentage absolute difference as the outcome measure. RESULTS: Concordances for the presence of calcium between duplicate scans were high and similar for both EBT and MDCT. Concordance was high for all three extracoronary measures, with a kappa statistic of kappa = 0.94-0.96. For all three extracoronary sites, Bland-Altman plots demonstrated excellent agreement, with almost all measures falling within the boundaries of the 95% confidence limits of reproducibility. AVC interscan variability was approximately 8% for both AS and VS, with improved variability for EBT as compared with MDCT. Mitral annular calcification demonstrated slightly lower variability than AVC for both scanner types (approximately 6%), with no significant differences between MDCT and EBT. Of the three extracoronary sites, TAC had the highest variability (10%), with MDCT variability slightly lower than EBT variability (9.3 vs. 10.2%, respectively, P = NS). Agatson and volume scores for each of the three extracoronary sites were similar. CONCLUSIONS: Overall rescan measurement variabilities for extracoronary calcification are low and should not be an impediment to the use of this test for studying progression of extracoronary calcification over time.