Quantification of the Hardened Cement Paste Content in Fine Recycled Concrete Aggregates by Means of Salicylic Acid Dissolution

Adherent hardened cement paste attached to recycled concrete aggregates (RCA) generally presents a higher porosity than natural aggregates, which induces a lower porosity in the properties of RCA. The characterization of the adherent hardened cement paste content (HCPC) in the fine RCA would promote better applications of RCA in concrete, but the determination of HCPC in fine RCA is not well established. A simple method based on salicylic acid dissolution was specifically developed to quantify the HCPC in RCA, especially for RCA containing limestone aggregates. The results demonstrated that the soluble fraction in salicylic acid (SFSA) was equal to the HCPC for white cement and slightly lower for grey Portland cement, which was also confirmed by a theoretical approach using modelling the hydration of cement paste with the chemical equations and the stoichiometric ratios. The physical and mechanical properties of RCA (e.g., water absorption) were strongly correlated to the SFSA. For industrial RCA, SFSA did not give the exact value of HCPC, but it was sufficient to correlate HCPC with the other properties of RCA. The water absorption could be estimated with good accuracy for very fine RCA (laboratory-manufactured RCA or industrial RCA) by extrapolating the relationship between water absorption and HCPC, which is very important for concrete formulation.     

Aneurysms of the Internal Iliac Artery: Management Strategy

With the widespread use of CT scans, detection and treatment of internal iliac artery aneurysms (IIA) have become more frequent. In the last few years, endovascular repair has been added to the therapeutic arsenal. We reviewed the records of 38 patients treated for 44 IIA between 1987 and 1997 to assess immediate and long-term outcome using various therapeutic methods. Aneurysms were divided into three groups according to the circumstances of treatment. Group I included 25 IIA treated at the same time as abdominal aortic aneurysm (AAA). The morbidity/mortality rate in this group was comparable to that in patients who underwent isolated AAA repair. Group II included 14 IIA treated during follow-up of AAA repair. Most complications in this group were intraoperative. Group III included five isolated IIA not associated with AAA repair. Complications were similar to those in group I. On the basis of this retrospective analysis, we propose a management strategy in which open surgery, endovascular repair, or both are used, depending on the circumstances of treatment.     

Pharmacometabonomic association of cyclophosphamide 4‐hydroxylation in hematopoietic cell transplant recipients

The widely used alkylating agent cyclophosphamide (CY) has substantive interpatient variability in the area under the curve (AUC) of it and its metabolites. Numerous factors may influence the drug‐metabolizing enzymes that metabolize CY to 4‐hydroxycyclophosphamide (4HCY), the principal precursor to CY’s cytotoxic metabolite. We sought to identify endogenous metabolomics compounds (EMCs) associated with 4HCY formation clearance (ratio of 4HCY/CY AUC) using global metabolomics. Patients who undergo hematopoietic cell transplantation receiving post‐transplant CY (PT‐CY) were enrolled, cohort 1 (n = 26) and cohort 2 (n = 25) donating longitudinal blood samples before they started HCT (pre‐HCT), before infusion of the donor allograft (pre‐graft), before the first dose of PT‐CY (pre‐CY), and 24 h after the first dose of PT‐CY (24‐h post‐CY), which is also immediately before the second dose of CY. A total of 512 and 498 EMCs were quantitated in two cohorts, respectively. Both univariate linear regression with false discovery rate (FDR), and pathway enrichment analyses using a global association test were performed. At the pre‐CY time point, no EMCs were associated at FDR less than 0.1. At pre‐HCT, cohort 1 had one EMC (levoglucosan) survive the FDR threshold. At pre‐graft, cohort 1 and cohort 2 had 20 and 13 EMCs, respectively, exhibiting unadjusted p values less than 0.05, with the only EMCs having an FDR less than 0.1 being two unknown EMCs. At 24‐h post‐CY, there were three EMCs, two ketones, and threitol, at FDR less than 0.1 in cohort 2. These results demonstrate the potential of pharmacometabonomics, but future studies in larger samples are needed to optimize CY.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

We report the first pharmacometabonomic study of the association of plasma EMCs with cyclophosphamide pharmacokinetics, specifically the ratio of 4HCY/CY AUC.

• WHAT QUESTION DID THIS STUDY ADDRESS?

This study addresses the question regarding if EMCs in the plasma before PT‐CY administration are associated with the ratio of 4HCY/CY AUC.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

This study adds to our knowledge that longitudinal collection of plasma EMC samples is feasible in HCT patients receiving PT‐CY. In addition, the plasma EMC changes over the ~21‐day time period that starts pre‐HCT to 24‐hr after the first PT‐CY dose.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

This study demonstrates the possibility of pharmacometabolomic research to evaluate the pharmacokinetics of a drug – in this case, cyclophosphamide – with a complex pharmacokinetic disposition.     

High risk for sleep apnea in the Berlin questionnaire and coronary artery disease

Introduction  

Obstructive sleep apnea (OSA) affects up to 30% of the adult population and is a risk factor for coronary artery disease (CAD). The diagnostic process, involving polysomnography, may be complex. Berlin questionnaire (BQ) is a validated and economical screening tool.