Ischemic Stroke in Patients With Intracranial Dural Arteriovenous Fistulas

Background/PurposeIntracranial dural arteriovenous fistulas (DAVFs) can be complicated by ischemic stroke. This study investigated the frequency and determinants of ischemic stroke in patients with intracranial DAVF.MethodsWe conducted a retrospective study of consecutive patients with intracranial DAVF. Patients with pure hemorrhagic stroke or without available brain imaging for clarifying stroke type were excluded. DAVF was diagnosed by cerebral catheter angiography. Cognard classification and location of DAVFs were ascertained. The clinical characteristics, outcome, and radiographic findings were recorded. Factors associated with occurrence of ischemic stroke in the patients with DAVFs were determined.ResultsA total of 134 patients were enrolled. Six patients (4.5%) had ischemic stroke (mean age: 53.8 ± 13.4 years) and 128 patients were free from stroke (mean age: 55.4 ± 15.2 years). Men accounted for 83% in the ischemic stroke group and 34% in the non-stroke group. Chemosis, exophthalmos and tinnitus were more frequent in the non-stroke group, whereas seizure and mental decline were more frequent in the ischemic stroke group. DAVF was associated with highest risk of ischemic stroke at locations other than the cavernous sinus or large sinuses. Ischemic stroke also correlated with types of DAVF involving cortical venous drainage, including type IIb (18%), III (15%), and IV (100%). No patient with DAVF type I and IIa had ischemic stroke. The rate of ischemic stroke in patients with concomitant DAVF and cerebral sinus thrombosis was higher than in DAVF patients without cerebral sinus thrombosis. Venous infarct was the major subtype of ischemic stroke in five DAVF patients. Endovascular therapy was the most common choice in both groups, and fewer patients in the ischemic stroke group did not receive any treatment for DAVFs.ConclusionLocation and type of DAVF were two important factors related to the occurrence of ischemic stroke in DAVF patients

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

The Impact and The Adaptive Strategies of Global Climate Change on Agricultural Production

氣候變遷對農業生產已知會造成相當大的衝擊，唯目前國內與此有關之研究仍十分有限。一般說來，溫度提昇對C4型之作物有正面的影響。而二氧化碳濃度之增加則有利於對C3型之作物之生產。對花卉、蔬菜等短期作物而言，氣候變遷對其影響較小。對果樹而言，高二氧化碳濃度、高溫也有利於生長。為了因應未來對糧食的需求，仍有必要推動有關氣候變遷方面的研究。 Agricultural production is known to be affected by climate change. However only limited studies are conducted in Taiwan. In general, higher temperature has positive impact on C4 crop species. Elevated CO2 may also be beneficiary to C3 crop species. Shorter-season flowers and vegetable crops are some what climate change-independent. Tropical fruit trees seem to be more responsive to elevated temperature and CO2. However, for meeting the demand in food need in the future researches related to climate change are needed

Color Doppler ultrasonography as an alternative tool for postoperative evaluation of collaterals after indirect revascularization surgery in Moyamoya disease

<div><p>The cerebral hypoperfusion caused by chronic progressive stenosis or occlusion of intracranial arteries in moyamoya disease can be treated by direct bypass or indirect revascularization procedures. The extent of collaterals from the external carotid artery (ECA) after indirect revascularization surgery is the key point of angiographic follow-up, and the invasiveness of angiography impelled us to investigate the role of ultrasonography in the evaluation of collaterals. We hypothesized that the collaterals shown on angiography might produce corresponding hemodynamic changes in color Doppler ultrasonography. We prospectively recruited moyamoya patients who underwent indirect revascularization surgery and received both preoperative and postoperative angiography and color Doppler ultrasound studies. The collaterals on angiography were graded according to Matsushima method. A total of 21 patients (age, 17 ± 10.2 years) with 24 operated hemispheres were enrolled. Patients who showed better collateral establishment by angiography had higher end-diastolic velocity (EDV), lower resistance index (RI), and larger flow volume in the superficial temporal artery (STA) and ECA (all p < 0.05). In STA, increase of EDV greater than 13.5 cm/sec or reduction of RI greater than 0.19 after operation corresponded to 94% of Matsushima grade A+B. In ECA, post-operative EDV greater than 22 cm/sec or increase of EDV greater than 6.4 cm/sec also corresponded to 94% of Matsushima grade A+B. Our findings revealed potential roles of color Doppler ultrasonography in identifying patients with poor collaterals after indirect revascularization procedures.</p></div

Relationship between Matsushima grades and postoperative ultrasonographic parameters of the ipsilateral intracranial arteries.

<p>Matsushima grades were correlated with the postoperative velocities of ipsilateral ACA, MCA and PCA. (ACA, anterior cerebral artery; MCA, middle cerebral artery; PCA, posterior cerebral artery; PSV, peak-systolic velocity; mean V, mean velocity; PI, pulsatility index; *, <0.05; **, <0.01.).</p

Prediction effect of the ultrasonic hemodynamic parameters of STA and ECA to Matsushima grades A+B.

<p>Prediction effect of the ultrasonic hemodynamic parameters of STA and ECA to Matsushima grades A+B.</p

ROC analysis for prediction of Matsushima grade A+B by the ultrasonographic parameters of STA and ECA.

<p>The area under the curve of ROC (AUC) of each parameter was also shown, ranging from 0.75–0.87.</p

Relationship between Matsushima grades and postoperative ultrasonographic changes of the contralateral extracranial arteries.

<p>Matsushima grades were not correlated with the post-operative changes in all of the parameters of the contralateral STA, ECA, and ICA.</p

Relationship between Matsushima grades and postoperative ultrasonographic changes of the ipsilateral extracranial arteries.

<p>Matsushima grades were correlated with the post-operative changes in EDV, RI, PI, and FV of ipsilateral STA and ECA. (STA, superficial temporal artery; ECA, external carotid artery; ICA, internal carotid artery; ΔPSV, post-operative change of peak-systolic velocity; ΔEDV, post-operative change of end-diastolic velocity; ΔRI, post-operative change of resistance index; ΔPI, post-operative change of pulsatility index; ΔFV, post-operative change of flow volume; *, <0.05; **, <0.01).</p

Relationship between Matsushima grades and postoperative changes of the ipsilateral intracranial arteries.

<p>Matsushima grades were not correlated with all the postoperative changes in the intracranial arteries.</p