Etiology and Antimicrobial Susceptibility of Middle Ear Fluid Pathogens in Costa Rican Children With Otitis Media Before and After the Introduction of the 7-Valent Pneumococcal Conjugate Vaccine in the National Immunization Program: Acute otitis media microbiology in Costa Rican children

Acute otitis media (AOM) microbiology was evaluated in children after 7-valent pneumococcal conjugate vaccine (PCV7) introduction in Costa Rica (private sector, 2004; National Immunization Program, 2009).This was a combined prospective and retrospective study conducted in a routine clinical setting in San José, Costa Rica. In the prospective part of the study, which was conducted post-PCV7 introduction (2010–2012), standard bacteriological procedures were used to evaluate the etiology and serotype distribution of middle ear fluid samples collected by tympanocentesis or otorrhea from children aged 3–59 months diagnosed with AOM. E-tests were used to evaluate antimicrobial susceptibility in culture-positive samples. Retrospective data recorded between 1999 and 2004 were used for comparison of bacterial etiology and serotype distribution before and after PCV7 introduction. Statistical significance was evaluated in bivariate analyses at the P-value < 0.05 level (without multiplicity correction).Post-PCV7 introduction, Haemophilus influenzae was detected in 118/456 and Streptococcus pneumoniae in 87/456 AOM episodes. Most H. influenzae isolates (113/118) were non-typeable. H. influenzae was more (27.4% vs 20.8%) and S. pneumoniae less (17.1% vs 25.5%) frequently observed in vaccinated (≥2 PCV7 doses or ≥1 PCV7 dose at >1 year of age) versus unvaccinated children. S. pneumoniae non-susceptibility rates were 1.1%, 34.5%, 31.7%, and 50.6% for penicillin, erythromycin, azithromycin, and trimethoprim/sulfamethoxazole (TMP-SMX), respectively. H. influenzae non-susceptibility rate was 66.9% for TMP-SMX. Between pre- and post-PCV7 introduction, H. influenzae became more (20.5% vs 25.9%; P-value < 0.001) and S. pneumoniae less (27.7% vs 19.1%; P-value = 0.002) prevalent, and PCV7 serotype proportions decreased among pneumococcal isolates (65.8% vs 43.7%; P-value = 0.0005). Frequently identified pneumococcal serotypes were 19F (34.2%), 3 (9.7%), 6B (9.7%), and 14 (9.7%) pre-PCV7 introduction, and 19F (27.6%), 14 (8.0%), and 35B (8.0%) post-PCV7 introduction.Following PCV7 introduction, a change in the distribution of AOM episodes caused by H. influenzae and pneumococcal serotypes included in PCV7 was observed in Costa Rican children. Pneumococcal vaccines impact should be further evaluated following broader vaccination coverage.     

Site-specific association between distal aortic pulse wave velocity and peripheral arterial stenosis severity: a prospective cardiovascular magnetic resonance study

Background

Vascular disease expression in one location may not be representative for disease severity in other vascular territories, however, strong correlation between disease expression and severity within the same vascular segment may be expected. Therefore, we hypothesized that aortic stiffening is more strongly associated with disease expression in a vascular territory directly linked to that aortic segment rather than in a more remote segment. We prospectively compared the association between aortic wall stiffness, expressed by pulse wave velocity (PWV), sampled in the distal aorta, with the severity of peripheral arterial occlusive disease (PAOD) as compared to atherosclerotic markers sampled in remote vascular territories such as PWV in the proximal aorta and the normalized wall index (NWI), representing the vessel wall thickness, of the left common carotid artery.

Methods

Forty-two patients (23 men; mean age 64±10 years) underwent velocity-encoded cardiovascular magnetic resonance (CMR) in the proximal and distal aorta, whole-body contrast-enhanced MR angiography (CE-MRA) and carotid vessel wall imaging with black-blood CMR in the work-up for PAOD. Strength of associations between aortic stiffness, carotid NWI and peripheral vascular stenosis grade were assessed and evaluated with multiple linear regression.

Results

Stenosis severity correlated well with PWV in the distal aorta (Pearson r_P=0.64, p<0.001, Spearman r_S=0.65, p<0.001) but to a lesser extent with PWV in the proximal aorta (r_P=0.48, p=0.002, r_S=0.22, p=0.18). Carotid NWI was not associated with peripheral stenosis severity (r_P=0.17, p=0.28, r_S=0.14, p=0.37) nor with PWV in the proximal aorta (r_P=0.22, p=0.17) nor in the distal aorta (r_P=0.21, p=0.18). Correlation between stenosis severity and distal aortic PWV remained statistically significant after correction for age and gender.

Conclusions

Distal aortic wall stiffness is more directly related to peripheral arterial stenosis severity than markers from more remote vascular territories such as proximal aortic wall stiffness or carotid arterial wall thickness. Site-specific evaluation of vascular disease may be required for full vascular risk estimation.     

Angiographic and clinical outcomes of late total occlusion versus treatment failure without late total occlusion in patients after intracoronary radiation therapy for in-stent restenosis

This study aimed to compare the outcomes of patients with late total occlusion (LTO) versus patients with recurrence in the absence of LTO after intracoronary radiation therapy for in-stent restenosis. LTO, especially in the context of acute myocardial infarction, after intracoronary radiation therapy for in-stent restenosis, is associated with negative clinical outcomes after 6 and 12 months compared with in-stent restenosis without LTO.     

Clinical, angiographic, and intravascular ultrasound characteristics of early saphenous vein graft failure

OBJECTIVES: We sought to examine saphenous vein graft (SVG) lesions that fail within the first year after operation. BACKGROUND: Saphenous vein grafts remain patent for approximately 10 years; however, up to 15% to 20% of SVGs become occluded within the first year. METHODS: We studied 100 patients who underwent percutaneous coronary intervention (PCI) for early (<1 year post-implantation) SVG failure lesions and compared them with a diabetes- and hypercholesterolemia-matched cohort of late SVG failures (>1 year). Coronary angiography and intravascular ultrasound images were analyzed. RESULTS: The majority of patients in both groups were males who presented with unstable angina; 36% were diabetic. Graft ages were 6.0 +/- 2.9 months and 105.4 +/- 50.8 months, respectively. The early SVG failure lesion location was more often ostial or proximal (62% vs. 42%, respectively). Early SVG failures were angiographically smaller than late failures (reference: 2.47 +/- 0.86 mm vs. 3.26 +/- 0.83 mm, p < 0.001) but had similar lesion lengths. Intravascular ultrasound showed that early failure lesions had smaller proximal and distal reference lumen areas (7.3 +/- 6.8 mm2 vs. 10.6 +/- 3.8 mm2, p = 0.026) and greater reference plaque burden than late failures (52.3% vs. 36.1%, p < 0.001). After PCI, 20.6% of early and 30.6% of late failure lesions had creatine kinase-myocardial band (CK-MB) greater than twice normal. CONCLUSIONS: Early SVG failure is mostly proximal or ostial, lesions appear focal, and early SVGs appear smaller than late SVGs. Intravascular ultrasound shows significant reference segment plaque burden, suggesting more severe, diffuse SVG disease.     

Human pluripotent stem cell-derived neural constructs for predicting neural toxicity

Human pluripotent stem cell-based in vitro models that reflect human physiology have the potential to reduce the number of drug failures in clinical trials and offer a cost-effective approach for assessing chemical safety. Here, human embryonic stem (ES) cell-derived neural progenitor cells, endothelial cells, mesenchymal stem cells, and microglia/macrophage precursors were combined on chemically defined polyethylene glycol hydrogels and cultured in serum-free medium to model cellular interactions within the developing brain. The precursors self-assembled into 3D neural constructs with diverse neuronal and glial populations, interconnected vascular networks, and ramified microglia. Replicate constructs were reproducible by RNA sequencing (RNA-Seq) and expressed neurogenesis, vasculature development, and microglia genes. Linear support vector machines were used to construct a predictive model from RNA-Seq data for 240 neural constructs treated with 34 toxic and 26 nontoxic chemicals. The predictive model was evaluated using two standard hold-out testing methods: a nearly unbiased leave-one-out cross-validation for the 60 training compounds and an unbiased blinded trial using a single hold-out set of 10 additional chemicals. The linear support vector produced an estimate for future data of 0.91 in the cross-validation experiment and correctly classified 9 of 10 chemicals in the blinded trial.There is a pressing need for improved methods to assess the safety of drugs and other compounds (1–5). Success rates for drug approval are declining despite higher research and development spending (6), and clinical trials often fail due to toxicities that were not identified through animal testing (7). In addition, most of the chemicals in commerce have not been rigorously assessed for safety despite growing concerns over the potential impact of industrial and environmental exposures on human health (2–5). Animal models are costly, time consuming, and fail to recapitulate many aspects of human physiology, which has motivated agencies such as the National Institutes of Health (NIH) and the US Environmental Protection Agency (EPA) to initiate programs that emphasize human cellular approaches for assessing the safety of drugs (1) and environmental chemicals (2, 3). In vitro cellular models that accurately reflect human physiology have the potential to improve the prediction of drug toxicity early in the development pipeline (1) and would provide a cost-effective approach for testing other sources of chemical exposure, including food additives, cosmetics, pesticides, and industrial chemicals (2–5).The human brain is particularly sensitive to toxic insults during development and early childhood (8), and there is growing concern that exposure to environmental chemicals may be linked to the rising incidence of neurodevelopmental disorders worldwide (4). Human brain development is mediated by highly coordinated cellular interactions between functionally distinct cell types that include neurons, glia, blood vessels, and microglia (9–15), each of which may be involved in neurotoxicity mechanisms (16–18). The cellular diversity of the developing brain complicates efforts to assess developmental neurotoxicity in vitro, because toxins might target numerous distinct cell types or cellular interactions and the underlying toxicity mechanisms are often unknown (3–5). Neurotoxicity has been evaluated using brain-derived cells in aggregate culture or coculture, neural stem cells, and other in vitro platforms, and these studies suggest that complex neurotoxic effects can be mimicked by incorporating cellular diversity into the model system (16, 18–20). However, many of these studies rely on animal cells that poorly reflect human physiology or primary human cells that are not scalable and introduce batch variability.Although in vitro human cellular models have historically been hampered by inadequate access to cellular components of the human brain, human embryonic stem (ES) cells (21) and induced pluripotent stem (iPS) cells (22, 23) now offer a scalable source for tissue-specific cell types. Here, reproducible 3D neural constructs that incorporated vascular and microglial components were fabricated for developmental neurotoxicity screening by culturing precursor cells derived from the H1 human ES cell line on synthetic hydrogels under defined conditions. Machine learning was used to build a predictive model from RNA sequencing (RNA-Seq) data for neural constructs exposed to a training set of 60 toxic and nontoxic chemicals and then to make predictions in a blinded trial using a set of 10 additional compounds.     

Characterization of Brown Adipose Tissue in a Diabetic Mouse Model with Spiral Volumetric Optoacoustic Tomography

Purpose

Diabetes is associated with a deterioration of the microvasculature in brown adipose tissue (BAT) and with a decrease in its metabolic activity. Multispectral optoacoustic tomography has been recently proposed as a new tool capable of differentiating healthy and diabetic BAT by observing hemoglobin gradients and microvasculature density in cross-sectional (2D) views. We report on the use of spiral volumetric optoacoustic tomography (SVOT) for an improved characterization of BAT.

Procedures

A streptozotocin-induced diabetes model and control mice were scanned with SVOT. Volumetric oxygen saturation (sO₂) as well as total blood volume (TBV) in the subcutaneous interscapular BAT (iBAT) was quantified. Segmentation further enabled separating feeding and draining vessels from the BAT anatomical structure.

Results

Scanning revealed a 46 % decrease in TBV and a 25 % decrease in sO₂ in the diabetic iBAT with respect to the healthy control.

Conclusions

These results suggest that SVOT may serve as an effective tool for studying the effects of diabetes on BAT. The volumetric optoacoustic imaging probe used for the SVOT scans can be operated in a handheld mode, thus potentially providing a clinical translation route for BAT-related studies with this imaging technology.

     

Treatment of severe osteochondral defects of the knee by combined autologous bone grafting and autologous chondrocyte implantation using fibrin gel

Purpose

Severe symptomatic and unstable osteochondral defects of the knee are difficult to treat. A variety of surgical techniques have been developed. However, the optimal surgical technique is still controversial. We present a novel technique in which autologous bone grafting is combined with gel-type autologous chondrocyte implantation (GACI).

Methods

Isolated severe osteochondral defects of the medial or lateral femoral condyle were treated by a two-step procedure. Firstly, chondrocytes were harvested during arthroscopy and cultured for 6?weeks. Secondly, a full thickness corticospongious autologuos bone graft, harvested from the medial or lateral femur condyle, is impacted in the defect and covered by GACI. The fibrin gel fills up to the exact shape of the chondral lesion and polymerizes within 3?min after application.

Results

From 2009 to 2011, 9 patients, median age 35?years (range 23–47), were treated by the combined autologous bone grafting and GACI technique. Median defect size was 7.1?cm² (range 2.5–12.0), and median depth of the lesion was 0.9?cm (range 0.8–1.2). Median follow-up was 9?months (range 6–12?months). Six patients were available for 12-month follow-up. The mean IKDC score showed a 6-month improvement from 35 (SD?±?16) to 51 (SD?±?18) (n?=?9; p?=?0.01), and a 1-year improvement from 35 (SD?±?16) to 57 (SD?±?20) (n?=?6; p?=?0.03). The mean KOOS improved from 44 (SD?±?16) to 62 (SD?±?19) (n?=?9; p?=?0.07) at 6-month follow-up and from 44 (SD?±?16) to 65 (SD?±?24) (n?=?6; p?=?0.1) at 12-month follow-up. There was one failure that needed conversion to a unicompartmental knee arthroplasty.

Conclusion

Combined autologous bone grafting and GACI may offer an alternative surgical option for severe and unstable osteochondral defects of the knee.

Level of evidence

IV.