Persistence profile of polyaromatic hydrocarbons in shallow and deep Gulf waters and sediments: effect of water temperature and sediment-water partitioning characteristics

Persistence profiles of selected polyaromatic hydrocarbons (PAHs) were analyzed depending on temperature variations in the water column and water-sediment interactions in the Gulf of Mexico. The PAHs studied include anthracene, fluoranthene, pyrene, and chrysene. The half-lives of PAHs in the deep waters (over 1000 m) are about twice as long as those in the shallow areas (100-150 m), and almost 2.5 times as long as those in the top layer (0-10 m) of the water column. The half-lives of the PAHs in the sediments are significantly longer. Among the PAHs studied, chrysene is the most persistent in the water column, and pyrene is the most persistent in the sediments. The half-life of chrysene in the shallow and deep waters is over 2.5 and about 5 years, respectively. For pyrene, the half-life in the shallow and deep sediments is about 9 and 16 years, respectively.

Biomechanical wall properties of human intracranial aneurysms resected following surgical clipping (IRRAs Project)

BACKGROUND AND PURPOSE

Individual rupture risk assessment of intracranial aneurysms is a major issue in the clinical management of asymptomatic aneurysms. Aneurysm rupture occurs when wall tension exceeds the strength limit of the wall tissue. At present, aneurysmal wall mechanics are poorly understood and thus, risk assessment involving mechanical properties is inexistent. Aneurysm computational hemodynamics studies make the assumption of rigid walls, an arguable simplification. We therefore aim to assess mechanical properties of ruptured and unruptured intracranial aneurysms in order to provide the foundation for future patient-specific aneurysmal risk assessment. This work also challenges some of the currently held hypotheses in computational flow hemodynamics research.

METHODS

A specific conservation protocol was applied to aneurysmal tissues following clipping and resection in order to preserve their mechanical properties. Sixteen intracranial aneurysms (11 female, 5 male) underwent mechanical uniaxial stress tests under physiological conditions, temperature, and saline isotonic solution. These represented 11 unruptured and 5 ruptured aneurysms. Stress/strain curves were then obtained for each sample, and a fitting algorithm was applied following a 3-parameter (C(10), C(01), C(11)) Mooney-Rivlin hyperelastic model. Each aneurysm was classified according to its biomechanical properties and (un)rupture status.

RESULTS

Tissue testing demonstrated three main tissue classes: Soft, Rigid, and Intermediate. All unruptured aneurysms presented a more Rigid tissue than ruptured or pre-ruptured aneurysms within each gender subgroup. Wall thickness was not correlated to aneurysmal status (ruptured/unruptured). An Intermediate subgroup of unruptured aneurysms with softer tissue characteristic was identified and correlated with multiple documented risk factors of rupture.

CONCLUSION

There is a significant modification in biomechanical properties between ruptured aneurysm, presenting a soft tissue and unruptured aneurysms, presenting a rigid material. This finding strongly supports the idea that a biomechanical risk factor based assessment should be utilized in the to improve the therapeutic decision making.

Prevalence and risk factors for quinolone resistance among Escherichia coli strains isolated from males with community febrile urinary tract infection

The purpose of this study was to evaluate the prevalence and clinical risk factors for quinolone resistance (QR) in E. coli strains from males with febrile urinary tract infection (FUTI). An ambispective cross-sectional study was performed in which we evaluated 153 males with a community FUTI caused by E. coli. Among the 153 FUTI episodes, 101 (66%) were due to quinolone susceptible E. coli strains while 52 (34%) were caused by QR E. coli strains. In the univariate analysis QR was associated with older age, higher Charlson scores, dementia, past UTI, urinary tract abnormalities, previous antibiotic use, particularly with fluoroquinolones (FQ), a healthcare-associated (HA)-UTI (HA-UTI) and to four of the components included in the definition of HA-UTI: hospital admission, nursing home residence, indwelling urethral catheter and invasive urinary instrumentation. In the multivariate analysis, HA-UTI (OR 3.82, 95% CI 1.3-11.24; P 0.015) and use of antimicrobials in the previous month (OR 5.82, 95% CI 2.3-14.88; P < 0.001) mainly with FQ (OR 13.97, 95% CI 2.73-71.53; P 0.002) were associated with QR. To have a HA-UTI and a previous use of FQ in the preceding month were strong risk factors for QR E. coli, and thus empirical antimicrobial treatment with quinolones should be avoided in these patients.

Detection of new respiratory viruses in hospitalized infants with bronchiolitis: a three-year prospective study

AIM

We have designed a study with the objective of describing the clinical impact of other viruses different from the respiratory syncytial virus (RSV) in hospitalized infants with bronchiolitis.

METHODS

A 3 year prospective study was conducted on infants admitted to the Paediatrics Department of the Severo Ochoa Hospital (Spain). We studied the frequency of 16 respiratory viruses. Clinical characteristics of RSV-only infections were compared with other single agent viral infections.

RESULTS

Positive results were confirmed in 275 (86.5%) of the 318 children studied. A single virus was detected in 196 patients and 79 were dual or multiple viral infections. RSV was detected in 61.3% of total bronchiolitis. Rhinovirus (RV) was 17.4% of the identified virus, followed by human bocavirus (HBoV), adenovirus and metapneumovirus (hMPV). Only RV, HBoV and hMPV were significant as single infections. RSV patients were younger than HBoV (p > 0.0001) and hMPV (p = 0.025). Seasonality was clearly different between them. Children with RSV infection needed treatment in the intensive care unit more frequently than others.

CONCLUSIONS

In hospitalized infants, RSV was the most frequent agent in bronchiolitis in winter, but other viruses were present in 47% of the patients. RV, HBoV and hMPV had a significant proportion of single infections. Clinical characteristics were similar amongst them, but seasonality was clearly different.

IFN-alpha amplifies human naive B cell TLR-9-mediated activation and Ig production

TLRs are a family of molecules that function as sensors for the detection of pathogens. TLR-9, expressed on B cells and pDCs, recognizes CpG motifs of unmethylated bacterial DNA and plays a role in the development of autoimmunity. The present study was designed to investigate the effects of IFN-alpha in combination with CpG ODN on the activation of CD27(-) naïve B cells and on Ig production. We provide evidence that CpG ODN not only induces a total and T-dependent, specific IgM response by naïve B cells but also their phenotypic differentiation in plasma cells, as demonstrated by the up-regulation of CD38 expression. We found that TLR-9 stimulation with CpG ODN induces IL-1beta, TNF-alpha, IL-10, and IL-6 production. Interestingly, we also found that CpG ODN induces naïve B cell maturation into memory cells, as demonstrated by the induction of CD27, AID mRNA expression, and IgG production. More importantly, our results demonstrate that IFN-alpha amplifies the inductive effect of CpG ODN on naïve B activation and on Ig production through a mechanism involving TLR-9/MyD88-dependent signaling. Moreover, we found that IFN-alpha enhances the frequency of CpG ODN-induced memory B cells. Our results may contribute to clarify the events promoting IFN-alpha-induced amplification of naïve B cell activation via TLR-9 for a better understanding of the pathogenesis of autoimmune disorders and may guide treatments targeting this pathway within B cells.