Washed red cells: theory and practice

Washing of red cells is sometimes performed to reduce allergic reactions due to contaminating plasma proteins or to reduce the concentration of potassium accumulating in the supernatant of red cells during storage as an alternative to transfusion of fresher red cells in patients at risk of hyperkalaemia. There are a variety of methods for washing red cells, and the laboratory data suggest that variables such as age of red cell before washing, washing method and solution, storage medium and length of storage time after washing can all effect the final red cell quality. Studies suggest that washing removes 90–95% plasma, but the proportion of units below 0·05 mg/dl IgA (equivalent to IgA deficient) is variable dependent upon methods used. Although potassium levels are reduced immediately following washing, the rate of leakage following subsequent storage is method-dependent, requiring careful consideration of shelf life if potassium reduction is the goal. Other markers of red cell quality such as haemolysis are negatively impacted by washing so a reduced shelf life compared to standard red cells is appropriate, especially following irradiation. Data from animal models and clinical studies on possible additional benefits of washing, such as reduced lung or kidney injury, are mixed, ranging from some benefit to some harm, and further studies are warranted.     

Traditional Cardiovascular Risk Factors and the Presence of Obstructive Coronary Artery Disease in Men and Women

Background

Extensive research has demonstrated the importance of traditional cardiovascular risk factors in predicting acute coronary events. Our main objective was to evaluate the relationship between traditional risk factors and the presence of obstructive coronary artery disease (CAD), and to explore potential differences in men vs women.

Methods

An observational study was conducted in a population-based cohort of stable patients who underwent cardiac catheterization in Ontario, Canada. We examined the relationship of diabetes, hypertension, hyperlipidemia, and smoking with the presence of obstructive CAD in men and women using multivariable logistic regression models.

Results

Of the 46,490 patients who were included in our study, 61.2% were men and 38.8% were women. We found that 97% of patients with obstructive CAD had at least 1 conventional cardiovascular risk factor. The adjusted odds ratios (ORs) for obstructive CAD in women with diabetes (OR, 1.51), hypertension (OR, 1.38), and smoking (OR, 1.39) were statistically significantly greater than in men (OR, 1.20 for diabetes; OR, 1.08 for hypertension; OR, 1.14 for smoking; P < 0.001). The sex difference was even greater for patients with multiple risk factors. For example, the association with obstructive CAD in women with 4 cardiac risk factors (OR, 4.30; 95% confidence interval, 3.49-5.28) was almost doubled compared with men (OR, 2.26; 95%confidence interval, 1.99-2.57; P < 0.001).

Conclusions

Almost all patients with stable CAD undergoing cardiac catheterization had at least 1 traditional cardiac risk factor. Importantly, the association between multiple cardiac risk factors and the presence of obstructive CAD is substantially stronger in women than men.     

Haplotype-based study of the association of alcohol and acetaldehyde-metabolising genes with alcohol dependence (with or without comorbid anxiety symptoms) in a Cape Mixed Ancestry population

Alcohol dependence (AD) has a large heritable component. Genetic variation in genes involved in the absorption and elimination of ethanol have been associated with AD. However, some of these polymorphisms are not present in an African population. Previous studies have reported that a type of AD which is characterized by anxious behaviour may be a genetically specific subtype of AD. We investigated whether variation in genes encoding cytochrome P450 2E1 (CYP2E1) or acetaldehyde-metabolising enzymes (ALDH1A1, ALDH2) might alter the risk of AD, with and without symptoms of anxiety, in a Cape population with mixed ancestry. Eighty case control pairs (one with AD, one without AD) were recruited and individually matched for potential confounders. Genotype data were available for 29 single-nucleotide polymorphisms (SNPs) across the three genes. Linkage disequilibrium D′ values were evaluated for all pairwise comparisons. Allele and haplotype frequencies were compared between cases and controls using a χ ² test. The ACAG haplotype in block 4 of the ALDH1A1 gene provided evidence of an association with AD (p?=?0.03) and weak evidence of an association with AD without symptoms of anxiety (p?=?0.06). When a genetic score was constructed using SNPs showing nominal evidence of association with AD, every extra risk allele increased the odds of AD by 35 % (OR 1.35, 95%CI 1.08, 1.68, p?=?0.008) and the odds of having AD with anxiety symptoms increased by 53 % (OR 1.53, 95%CI 1.14, 2.05, p?=?0.004). Although our results are supported by previous studies in other populations, they must be interpreted with caution due to the small sample size and the potential influence of population stratification.     

Caspase Inhibition Via A3 Adenosine Receptors: A New Cardioprotective Mechanism Against Myocardial Infarction

Purpose

2-CL-IB-MECA, (A₃ adenosine receptor agonist)(A₃AR) mediated cardioprotection is well documented although the associated intracellular signalling pathways remain unclear. Here we demonstrate a role of the pro-survival signalling pathways MEK1/2-ERK1/2 and PI3K/AKT and their effect on modifying Caspase-3 activity in A₃AR mediated cardioprotection.

Methods

Isolated perfused rat hearts or primary adult rat cardiac myocytes were subjected to ischaemia/hypoxia and reperfusion/reoxygenation, respectively. 2-CL-IB-MECA (1 nM) was administered at the onset of reperfusion/reoxygenation in the presence and absence of either the PI3K inhibitor Wortmannin (5 nM) or MEK1/2 inhibitor UO126 (10 μM). Heart tissues were harvested for assessment of p-ERK1/2(Thr202/Tyr204) or p-AKT (Ser-473) status or underwent infarct size assessment. Cardiac myocytes underwent flow-cytometric analysis for apoptosis, necrosis, cleaved-caspase 3/p-BAD (Ser-112 and Ser-136) activity post-reoxygenation.

Results

2-CL-IB-MECA significantly reduced infarct size compared to non-treated controls, where co-administration with either of the kinase inhibitors abolished the infarct sparing effects. Administration of 2-CL-IB-MECA at reperfusion significantly upregulated the status of p-ERK1/2 and p-AKT compared to time matched controls in a UO126 and Wortmannin sensitive manner respectively. 2-CL-IB-MECA when administered throughout reoxygenation significantly reduced apoptosis, necrosis, cleaved-caspase 3 activity and increased p-BAD (Ser-112) and p-BAD (Ser-136) activity in myocytes subjected to hypoxia/reoxygenation injury. The cytoprotective effect was abolished by co-administration with the kinase inhibitors Wortmannin and/or UO126.

Conclusions

We have described the molecular mechanisms associated with A₃AR mediated cardioprotection indicating a role for the pro-survival signalling pathways that decrease caspase-3 activity. These observations provide novel insight into the pharmacological effects of A₃ARs in ameliorating myocardial ischaemia/reperfusion injury.     

The CSD Drug Subset: The Changing Chemistry and Crystallography of Small Molecule Pharmaceuticals

We report the generation and statistical analysis of the CSD drug subset: a subset of the Cambridge Structural Database (CSD) consisting of every published small-molecule crystal structure containing an approved drug molecule. By making use of InChI matching, a CSD Python API workflow to link CSD entries to the online database Drugbank.ca has been produced. This has resulted in a subset of 8632 crystal structures, representing all published solid forms of 785 unique drug molecules. We hope that this new resource will lead to improvements in targeted cheminformatics and statistical model building in a pharmaceutical setting. In addition to this, as part of the Advanced Digital Design of Pharmaceutical Therapeutics collaboration between academia and industry, we have been given the unique opportunity to run comparative analysis on the internal crystal structure databases of AstraZeneca and Pfizer, alongside comparison to the CSD as a whole.     

Impact of Method of Preparation of Amorphous Solid Dispersions on Mechanical Properties: Comparison of Coprecipitation and Spray Drying

Usage of the amorphous phase of compounds has become the method of choice to overcome oral bioavailability problems related to poor solubility. Due to the unstable nature of glasses, it is clear that the method of preparation of the amorphous glass will have an impact on physical/chemical stability and in turn in vivo performance. The method of preparation can also have a profound impact on the mechanical properties of the amorphous phase. We have explored the impact of preparation method on the mechanical properties of an amorphous solid dispersion using a development compound, GDC-0810. Three methods were used to generate amorphous solid dispersions (ASDs) of 50% GDC-0810 with hydroxypropyl methylcellulose acetate succinate: (1) spray drying, (2) coprecipitation using overhead mixing, and (3) coprecipitation using resonant acoustic mixing. All 3 methods were found to generate ASDs with good phase mixing and similar glass transition temperatures. Coprecipitated ASD powders (overhead mixing and resonant acoustic mixing) demonstrated superior tabletability and flow properties when compared to the spray drying powder. Careful choice of manufacturing process can be used to tune material properties of ASDs to make them more amenable for downstream operations like tableting. Acoustic mixing has been demonstrated as a scalable new method to make ASDs through coprecipitation.