Hemorrhagic Stroke Induces a Time-Dependent Upregulation of miR-150-5p and miR-181b-5p in the Bloodstream

To date, the only effective pharmacological treatment for ischemic stroke is limited to the clinical use of recombinant tissue plasminogen activator (rtPA), although endovascular therapy has also emerged as an effective treatment for acute ischemic stroke. Unfortunately, the benefit of this treatment is limited to a 4.5-h time window. Most importantly, the use of rtPA is contraindicated in the case of hemorrhagic stroke. Therefore, the identification of a reliable biomarker to distinguish hemorrhagic from ischemic stroke could provide several advantages, including an earlier diagnosis, a better treatment, and a faster decision on ruling out hemorrhage so that tPA may be administered earlier. microRNAs (miRNAs) are stable non-coding RNAs crucially involved in the downregulation of gene expression via mRNA cleavage or translational repression. In the present paper, taking advantage of three preclinical animal models of stroke, we compared the miRNA blood levels of animals subjected to permanent or transient middle cerebral artery occlusion (MCAO) or to collagenase-induced hemorrhagic stroke. Preliminarily, we examined the rat miRNome in the brain tissue of ischemic and sham-operated rats; then, we selected those miRNAs whose expression was significantly modulated after stroke to create a list of miRNAs potentially involved in stroke damage. These selected miRNAs were then evaluated at different time intervals in the blood of rats subjected to permanent or transient focal ischemia or to hemorrhagic stroke. We found that four miRNAs-miR-16-5p, miR-101a-3p, miR-218-5p, and miR-27b-3p-were significantly upregulated in the plasma of rats 3 h after permanent MCAO, whereas four other different miRNAs-miR-150-5p, let-7b-5p, let-7c-5p, and miR-181b-5p-were selectively upregulated by collagenase-induced hemorrhagic stroke. Collectively, our study identified some selective miRNAs expressed in the plasma of hemorrhagic rats and pointed out the importance of a precise time point measurement to render more reliable the use of miRNAs as stroke biomarkers.

pH-Driven Conformational Switching of Quinoxaline Cavitands in Polymer Matrices

While pH-driven interconversion of tetraquinoxaline cavitands (QxCav) from vase to kite conformation has been extensively studied both in solution and at interfaces, cavitands behavior in solid matrices is still unexplored. Therefore, the synthesis of a new class of quinoxaline cavitand based copolymers is here reported; a soluble linear poly(butyl methacrylate) (PBMA) and an insoluble cross-linked polydimethylsiloxane (PDMS), ensuring a convenient incorporation of the switchable unit, were chosen as polymer matrices. Conformational studies, performed both in solution and at the solid state, confirmed the retention of vase → kite switching behavior when moving from monomeric units to polymeric structures.

Unconventional metallic magnetism in LaCrSb3

Neutron-diffraction measurements in LaCrSb3 show a coexistence of ferromagnetic and antiferromagnetic sublattices below T(C)=126 K, with ordered moments of 1.65(4) and 0.49(4)mu(B)/formula unit, respectively (T=10 K), and a spin-reorientation transition at approximately 95 K. No clear peak or step was observed in the specific heat at T(C). Coexisting localized and itinerant spins are suggested.

Urinary calcium excretion in healthy school children

Two hundred and twenty Argentinian primary school children (122 boys, 98 girls, aged 6-13 years) were studied to establish reference values of 24-h urinary calcium excretion (UCa) and calcium/creatinine ratio (Ca/Cr) in 24-h urine collections and in first-morning urine samples. Mean UCa excretion was 2.05 +/- 1.40 mg/kg per day and the 95th percentile was 4.74 mg/kg per day. UCa excretion was higher in boys than girls (2.33 +/- 1.47 and 1.70 +/- 1.24 mg/kg per day respectively, P < 0.001). Statistically significant differences were found between the 6- to 9-year and the 10- to 13-year age groups (2.37 +/- 1.49 vs. 1.73 +/- 1.25 mg/kg per day, P < 0.001). Mean Ca/Cr ratios in 24-h collections and in first-morning urine samples were 0.129 +/- 0.086 and 0.105 +/- 0.079 for the group overall (P < 0.001). The Ca/Cr ratio in the first-morning urine sample correlated poorly with the 24-h calcium excretion, suggesting that the Ca/Cr ratio in first-morning urine samples cannot replace the 24-h measurement.