Cerebral perfusion in corresponding blood supply areas of transient ischemic attack patients with intracranial stenosis Seven cases of diamox-perfusion verified by magnetic resonance-perfusion-weighted imaging

BACKGROUND： Due to collateral circulation and cerebrovascular reserve, arterial stenosis and reduced cerebral blood flow may not necessarily indicate impaired cerebral peffusion. Therefore, according to degree of stenosis and clinical symptoms, interventional surgery to relieve arterial stenosis in transient ischemic attack （TIA） patients with major intracranial stenosis is imprudent. Rather, cerebral perfusion and reserve capacity are direct indicators for the assessment of degree and presence of cerebral ischemia. OBJECTIVE： To evaluate cerebral perfusion and reserve in TIA patients with major intracranial stenosis or occlusion using magnetic resonance-perfusion-weighted imaging （MR-PWl） data prior to and following diamox administration. DESIGN, TIME AND SETTING： A self-comparative, neuroimaging observation was performed at the Neurological Department and Radiological Center of the First Affiliated Hospital of Jinan University between December 2007 and April 2009. PARTICIPANTS： Seven acute TIA patients, who were admitted to the Neurological Department of the First Affiliated Hospital of Jinan University between December 2007 and April 2009, were enrolled in the present study. Magnetic resonance imaging confirmed that no acute cerebral infarction happened, nor did bleeding exist. Magnetic resonance angiography, transcranial Doppler ultrasound, and/or digital subtraction angiography confirmed the presence of major intracranial arterial stenosis. Clinical symptoms corresponded to blood supplying regions of the arterial stenosis. METHODS： Baseline MR-PWI was performed on seven patients with intracranial stenosis or occlusion. Two grams of acetazolamide （diamox） were orally administered after 2 days. A second PWl was performed after 2 hours to compare cerebral perfusion parameters prior to and following diamox administration. MAIN OUTCOME MEASURES： PWI results of cerebral perfusion prior to and following diamox administration. RESULTS： The baseline PWl from five patients indicated decreased cerebral perfusion areas. Following oral administration of diamox, cerebral perfusion significantly decreased in those areas. Moreover, new areas of decreased cerebral perfusion were observed in two out of the five patients. In one patient, no significant decrease in cerebral perfusion was found. In another patient, baseline PWl indicated decreased cerebral perfusion in the left hemisphere. However, normal perfusion was observed in both cerebral lobes following diamox administration. CONCLUSION： TIA patients with intracranial stenosis, who are diagnosed by PWI and exhibited decreased cerebral perfusion and reserve, might require further treatment such as intervention by angioptasty.

Cobalt‐N_(4) macrocyclic complexes for heterogeneous electrocatalysis of the CO_(2) reduction reaction

Metal-N_(4)(M-N_(4))macrocyclic complexes are interesting electrocatalysts due to their well-defined structures and rich molecular tuning.Among them,metal phthalocyanines have been widely studied for the carbon dioxide reduction reaction(CO_(2)RR)in heterogeneous systems and demonstrated good electrocatalytic performance.However,other complexes like metal corroles and metal porphyrins are much less explored,and often show inferior performances.In this study,three cobalt macrocyclic complexes,cobalt phthalocyanine,cobalt meso-tetraphenylporphyrin,and cobalt meso-triphenylcorrole(CoPc,CoTPP and CoTPC)are investigated in heterogeneous electrocatalysis of CO_(2)RR.Although CoPc/carbon nanotube(CNT)hybrid exhibits high electrocatalytic activity,CNT hybridization does not work for CoTPC and CoTPP that hold weak interactions with CNTs.By the drop-dry method with a high molecular loading of 5.4×10^(–7) mol cm^(–2),CoTPC and CoTPP could deliver appreciable electrode activities.Poly(4-vinylpyridine)(PVP)introduction is further demonstrated as a facile method to afford enhanced activities for CoTPP at low molecular loadings through enhancing molecule-substrate interactions.The partial current density of carbon monoxide for CoTPP+CNT/PVP is around 8 times higher than the sample without PVP at–0.67 V versus reversible hydrogen electrode.This work provides solutions to enhance the electrode activities of molecular electrocatalysts with weak substrate interactions in heterogeneous systems.

Main Components and Antioxidant Activity of Callisia repens Extracts

To study the main active components and antioxidant activity in vitro of extracts from Callisia repens , the contents of main active components such as total flavonoids, total anthocyanin and total sugar in the extracts were studied by spectrophotometry. The components and content of 18 kinds of metals were determined by ICP-MS mass spectrometry. Finally, the oxidative activity of the extract was evaluated by spectrophotometry. Results showed that the content of flavonoids, the total protein, the total sugar and the total anthocyanin in C. repens extract powder were 2.04%, 1.83%, 55.2% and 7.2%, respectively. Beneficial trace elements such as Ca, Mn, Mg in C. repens extracts were higher, while harmful heavy metals such as Pb, Hg, Ag, Co, Ge were very tiny or not detected at all. The IC 50 of C. repens was 0.265 mg/mL for scavenging DPPH·, and 1.16 mg/mL for scavenging ·OH free radical, the total reducing power of 1 mg extract was equivalent to that of 39 μg of Vc, and the extract showed no regular chelating power to ferrous ions. In conclusion, C. repens extracts have high content of natural active components, but extremely low content of the harmful heavy metals, and C. repens extract has good antioxidant capacity. Its antioxidant activity is realized by a variety of active factors through a synergistic mechanism. Thus, C. repens extract has great potential for developing into functional foods.