CT perfusion for response evaluation after interventional ablation of hepatocellular carcinoma: a prospective study

Background Computed tomography (CT) perfusion was found to be useful in assessing treatment response in a variety of cancers through the evaluation in the arterial perfusion changes. We investigated the performance of CT perfusion parameters for assessment of hepatocellular carcinoma (HCC) response to radiofrequency ablation (RFA) and trans-arterial chemoembolization (TACE). We conducted a prospective diagnostic test accuracy study that recruited 70 HCC patients who were scheduled to undergo TACE or RFA. For each dynamic CT scan acquisition, four single perfusion CT image maps were generated, including functional maps of blood flow (BF), blood volume (BV), mean transit time (MTT), and permeability surface (PS). Results In TACE-treated lesions, the BV achieved a sensitivity and specific of 100% and 83.3%, at a cutoff level of ≤ 122 ml/min/100 gm, for responders. Likewise, at a cutoff level of > 10 s, transit time had a sensitivity of 90.5% and specificity of 100%. At a cutoff level of ≤ 14 ml/min/100 gm, the PS had a sensitivity of 100% and specificity of 83.33% for responders. In RFA-treated lesions, at a cutoff level of ≤ 170 ml/min/100 gm and ≤ 11 ml/100 gm, the BF and BV had a sensitivity of 100% and specificity 100%, respectively, for responders. At a cutoff level of ≤ 11 ml/min/100 gm, PS had a sensitivity 77.27% and specificity 80%. Conclusions The present study confirms the feasibility of CT perfusion for assessment of response to TACE and RFA among patients with HCC.

The Influence of Hollow Carbon Sphere in Heterogeneous Catalysis

Hollow carbon spheres (HCSs) are hollow structured carbon particles of sizes ranging between micron and nanometre sizes with thin outer shells. They are of importance for their unique properties such as encapsulation ability, controllable permeability, surface functionality, high surface-to-volume ratios, and excellent chemical and thermal stabilities. In this communication, a precise description is presented of the synthesis, characterization, and applications of HCSs. Synthesis of HCSs is normally carried out in two ways, namely, hard-templating and soft-templating methods. These materials are characterized by modern techniques to investigate their structural and textural properties to get an insight into the material. Finally, the recent progress made in the applications of HCSs has been reported in the area of catalysis as a support material and energy storage device.

Research of the process of thermal processing of milk in a cylindrical pasteurizer

Cylindrical coaxial heaters are increasingly used in agricultural production. However, their widespread use is restrained by the fact that it is still necessary to supplement the calculation methodology, which would make it possible to take into account its geometric dimensions, dielectric and magnetic permeability, surface effect and proximity effect, uneven distribution of electric and magnetic fields along the heater, and a number of other factors when choosing the parameters of the heater. Such a task is relevant in the design of electric heaters for the production needs of dairy farms, taking into account what the methodology presented below has been developed. This technique gave a positive effect in relation to the development of an experimental electric pasteurizer.

Blood-brain barrier permeability in survivors of immune-mediated thrombotic thrombocytopenic purpura: a pilot study

Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a rare, life-threatening disorder of systemic microthrombosis and organ ischemia. The etiology of chronic cerebrovascular outcomes in iTTP survivors is largely unknown. In this pilot study, we measured blood-brain barrier (BBB) permeability in iTTP patients at the start of remission and 6 months later. This prospective pilot study included 7 adult patients with incident iTTP. Eligibility criteria included ADAMTS13 activity <10% and detectable inhibitor at diagnosis. Patients were recruited from London Health Sciences Centre in Canada (2017-2019) within 3 days of hospital admission and followed for 6 months after remission (defined as normalization of platelet count and lactate dehydrogenase with no clinical signs or symptoms of microvascular injury for more than 30 days after the last plasma exchange). All patients had cerebral CT perfusion scans with BBB permeability surface product measurements. Patients (5 women, 2 men) had a mean age of 48 years (range 21-77). At diagnosis, patients had a mean platelet count of 22 (standard deviation [SD] 25) x109/L. At the start of remission, mean BBB permeability surface product was 0.91 (0.30) mL/min/100g. Six months later, the mean permeability surface product was 0.56 (0.22) mL/min/100g, with mean difference: -0.312 mL/min/100g (95% confidence interval: -0.4729 to -0.1510; p=0.0032). In this pilot study of iTTP patients, pathologically increased BBB permeability was evident and, though there was some improvement, this persisted 6 months after remission. Future work will explore the chronicity of these findings and their clinical implications.

Prognostic Value of a New Integrated Parameter—Both Collateral Circulation and Permeability Surface—in Hemorrhagic Transformation of Middle Cerebral Artery Occlusion Acute Ischemic Stroke: Retrospective Cohort Study

BackgroundMultimodal CT, including CT angiography (CTA) and CT perfusion (CTP), was increasingly used in stroke triage. This study was to determine the relationship between a new integrated parameter—both collateral circulation and relative permeability surface (PS)—and the hemorrhagic transformation (HT) in acute ischemic stroke (AIS) with middle cerebral artery occlusion (MCAO).MethodsWe retrospectively reviewed consecutive AIS patients with MCAO who underwent baseline CTA/CTP within 4 h of symptom onset and follow-up susceptibility-weighted imaging (SWI) within 3 weeks. Collateral circulation was assessed on the baseline CTA. Baseline CTP data were postprocessed to generate PS parameter. The patients with poor collateral circulation and at the same time with high relative PS were classified as the group of both poor collateral circulation and high relative PS. HT was defined according to European Cooperative Acute Stroke Study II criteria on follow-up SWI imaging. Multivariate logistic regression analysis was performed using HT as an outcome variable.ResultsThe group of patients with both poor collateral circulation and high relative PS was thirteen and thirty-three (52%) developed HT of the final cohort sixty-three AIS patients with MCAO. Multivariate logistic analysis revealed the new integrated parameter—both collateral circulation and relative PS (odds ratio, 16.59; 95% confidence interval, 13.09–19.10; P < 0.001) was independent predictor of HT. The area under the curve was 0.85 (95% confidence interval, 0.81–0.89). The sensitivity was 57%, specificity 97% and positive predictive value 92%, negative predictive value 58%.ConclusionsFor AIS patients with MCAO, these with poor collateral circulation on CTA and at the same time with high relative PS on CTP were at high risk for HT.

A rapid dynamic in vivo near-infrared fluorescence imaging assay to track lung vascular permeability after acute radiation injury

Purpose: Develop an in vivo near-infrared (NIR) fluorescence imaging assay to quantify sequential changes in lung vascular permeability-surface area product (PS) in rodents. Methods: Dynamic NIR imaging methods for determining lung vascular permeability-surface area product were developed and tested on non-irradiated and 13 Gy irradiated rats with/without treatment with lisinopril. A physiologically-based pharmacokinetic (PBPK) model of Indocyanine Green (ICG) pulmonary disposition was applied to in vivo imaging data and PS was estimated. In vivo results were validated by five accepted assays: ex vivo perfused lung imaging, endothelial filtration coefficient (Kf) measurement, pulmonary vascular resistance measurement, Evan's blue dye uptake and histopathology. Results: PBPK modeled lung PS increased from 2.60±0.40 [CL: 2.42-2.78] mL/min in the non-irradiated group to 6.94±8.25 [CL: 3.56-10.31] mL/min in 13 Gy group after 42 days. Lisinopril treatment lowered PS in the 13Gy group to 4.76±6.17 [CL: 2.12-7.40] mL/min. A higher 5X change in PS was observed in rats exhibiting severe radiation injury. Ex vivo Kf (mL/min/cm H2O/g dry lung weight), a measure of pulmonary vascular permeability, showed similar trends in lungs of irradiated rats (0.164±0.081 [CL: 0.11-0.22]) compared to non-irradiated controls (0.022±0.003 [CL: 0.019-0.025]), with reduction to 0.070±0.035 [CL: 0.045-0.096] for irradiated rats treated with lisinopril. Similar trends were observed for ex vivo pulmonary vascular resistance, Evan's blue uptake, and histopathology. Conclusion: Our results suggest that dynamic in vivo NIR fluorescence imaging can replace current terminal assays. In vivo imaging accurately tracks changes in PS and lung interstitial transport in response to radiation injury.

Increased microvascular permeability and low level of low-density lipoprotein cholesterol predict symptomatic intracerebral hemorrhage in acute ischemic stroke

Symptomatic intracerebral hemorrhage is a serious potential complication of recombinant tissue-type plasminogen activator thrombolysis in acute ischemic stroke. We investigated the optimal imaging and clinical parameters to predict symptomatic intracerebral hemorrhage in acute ischemic stroke patients after recombinant tissue-type plasminogen activator therapy. We retrospectively reviewed 151 acute ischemic stroke patients with thrombolytic therapy, who were dichotomized into symptomatic intracerebral hemorrhage group and non–symptomatic intracerebral hemorrhage group. They underwent multimodal computed tomography, including the measurement of permeability surface. We compared the clinical and radiological characteristics between symptomatic intracerebral hemorrhage group and non–symptomatic intracerebral hemorrhage group, using univariate analysis. Receiver operating characteristic analysis and multivariate logistic regression analyses were then used to determine symptomatic intracerebral hemorrhage predictors. Of 151 patients, 14 patients (9.27%) developed symptomatic intracerebral hemorrhage on follow-up imaging. Relative permeability surface (infarct permeability surface/contralateral normal permeability surface) ( p < 0.05) and baseline low-density lipoprotein cholesterol level ( p < 0.05) were both predictors of symptomatic intracerebral hemorrhage. Receiver operating characteristic analysis of relative permeability surface revealed an optimal relative permeability surface threshold of 2.239, with an area under the curve of 0.87 (95% confidence interval, 0.732–1.0). The relative permeability surface was 2.239, the sensitivity for symptomatic intracerebral hemorrhage was 85.7%, the specificity was 94.9%, the positive predictive value was 70.6%, and the negative predictive value was 95.5%. For low-density lipoprotein cholesterol, the optimal threshold was 2.45, with an area under the curve of 0.726 (95% confidence interval, 0.586–0.867), the sensitivity for symptomatic intracerebral hemorrhage was 73.0%, the specificity was 64.3%, the positive predictive value was 67.16%, and the negative predictive value was 79.09%. Our study demonstrated that increased infarct permeability surface and low level of low-density lipoprotein cholesterol can be two predictors of symptomatic intracerebral hemorrhage. Detection of relative permeability surface and low-density lipoprotein cholesterol may help clinicians to identify acute ischemic stroke patients with the higher risk of symptomatic intracerebral hemorrhage; intravenous thrombolytic therapy should be carefully performed for patients with high relative permeability surface and low low-density lipoprotein cholesterol. We may take relative permeability surface and low-density lipoprotein cholesterol into account to refine therapeutic decision-making in acute ischemic stroke.

Antibacterial Activity and Mode of Action of β-caryophyllene on Bacillus cereus

Natural products such as essential oils (EOs) are secondary metabolites that can be obtained from either plant or animal sources or produced by microorganisms. Much attention has been given to exploring the use of secondary metabolites as natural antibacterial agents. This study investigates the antibacterial activity and mechanism of β-caryophyllene, a compound that can be found in various EOs, against Bacillus cereus. The minimum inhibitory concentration of β-caryophyllene against B. cereus was 2.5% (v/v), whereas killing kinetics of β-caryophyllene at minimum inhibitory concentration recorded complete bactericidal activity within 2 hours. Zeta-potential measurement in the cells treated with half the minimum inhibitory concentration of β-caryophyllene at 1.25% (v/v) showed an increase in the membrane permeability surface charge to –3.98 mV, compared to untreated cells (–5.46 mV). Intracellular contents leakage of UV-absorbing materials was detected in the cells treated with β-caryophyllene. Additionally, β-caryophyllene does not interfere with the efflux activity of B. cereus via the ethidium bromide influx/efflux activity. The results revealed that β-caryophyllene was able to alter membrane permeability and integrity of B. cereus, leading to membrane damage and intracellular content leakage, which eventually caused cell death.

Are transient changes in capillary surface area required to explain peritoneal transport in renal failure patients?

Background: Waniewski postulated a transient increase in peritoneal capillary surface area to fit their model predictions to experimental data of Heimburger measured in renal failure (RF) patients undergoing peritoneal dialysis (PD) but with only a 3.86% glucose dialysis fluid. The present aim is to propose a new mathematical model of the patient PD procedure that could closely fit the complete Heimburger measurement set without this postulate. Methods: The three-pore model of Rippe was used to describe transient changes in peritoneal volume and solute concentrations during a PD dwell. The predialysis, RF patient, plasma solute concentrations were assumed to remain constant during the dwell. The model was validated using the 3.86% glucose Heimburger measurements. Permeability surface area product parameters were chosen to match only the end-dwell peritoneal fluid glucose concentration and the end-dwell amounts of urea, creatinine, and Na+ removed from this simulated patient group. Then, this model was used to predict additional measurements by Heimburger on two other patient groups dialyzed with glucose concentrations of 2.27% and 1.36%, respectively. Parameters were unchanged when simulating these other patient groups. Results: To match the shape of the transient changes in drained volume and dialysis fluid glucose concentration for the 3.86% glucose group, it was necessary for only one parameter, the effective radius of glucose, to vary linearly in proportion to the dialysis fluid glucose concentration. This description was unchanged in the other two groups. Conclusion: Postulated transient increases in peritoneal capillary surface area were unnecessary to predict the entire Heimburger measurements.

Permeability-surface area product of the penumbra as a predictor of outcome after endovascular treatment of anterior circulation acute ischemic stroke

Background Permeability-surface product is a predictor of blood–brain barrier disruption, a condition that may be related to higher likelihoods of hemorrhagic transformations in acute stroke. Purpose To investigate whether permeability-surface product can be used as a parameter for predicting outcome after mechanical thrombectomy in patients with anterior circulation acute ischemic stroke. Material and Methods We retrospectively identified patients with acute middle cerebral artery stroke who underwent successful mechanical thrombectomy between November 2009 and July 2015. Multiple parameters (including age) and CT perfusion-related parameters (including permeability-surface product) were compared between patients with favorable (modified Rankin Scale [mRS] = 0–2) and unfavorable (mRS > 2) outcome. Results Thirty patients were included, 50% having favorable and 50% having unfavorable outcome. Younger age was significantly associated with favorable outcome ( P < 0.03). Other baseline characteristics, such as size of CT perfusion core infarction, perfusion abnormality, and presentation of subcortical infarction were not significantly different between groups. No significant difference was observed between groups for permeability-surface product in the ipsilateral penumbra or for the ratio between permeability-surface product penumbra value and contralateral normal brain (permeability-surface product ratio). Conclusions No significant difference was observed between patients with and without favorable outcome after mechanical thrombectomy for either permeability-surface product value or permeability-surface product ratio. Although permeability-surface product is a good predictor of blood–brain barrier disruption, this study revealed no evidence that either permeability-surface product value or permeability-surface product ratio is associated with future change in the penumbra.