Assessment of Liver Fibrosis with Diffusion-Weighted Magnetic Resonance Imaging Using Different b-values in Chronic Viral Hepatitis

Objective

To examine the effectiveness of apparent diffusion coefficient (ADC) values and to compare the reliability of different b-values in detecting and identifying significant liver fibrosis.

Subjects and Methods

There were 44 patients with chronic viral hepatitis (CVH) in the study group and 30 healthy participants in the control group. Diffusion-weighted magnetic resonance imaging (DWI) was performed before the liver biopsy in patients with CVH. The values of ADC were measured with 3 different b-values (100, 600, 1,000 s/mm²). In addition, liver fibrosis was classified using the modified Ishak scoring system. Liver fibrosis stages and ADC values were compared using areas under the receiver-operating characteristic (ROC) curve.

Results

The study group''s mean ADC value was not statistically significantly different from the control group''s mean ADC value at b = 100 s/mm² (3.69 ± 0.5 × 10⁻³ vs. 3.7 ± 0.3 × 10⁻³ mm²/s) and b = 600 s/mm² (2.40 ± 0.3 × 10⁻³ vs. 2.5 ± 0.5 × 10⁻³ mm²/s). However, the study group''s mean ADC value (0.99 ± 0.3 × 10⁻³ mm²/s) was significantly lower than that of the control group (1.2 ± 0.1 × 10⁻³ mm²/s) at b = 1,000 s/mm². With b = 1,000 s/mm² and the cutoff ADC value of 0.0011 mm²/s for the diagnosis of liver fibrosis, the mean area under the ROC curve was 0.702 ± 0.07 (p = 0.0015). For b = 1,000 s/mm² and the cutoff ADC value of 0.0011 mm²/s to diagnose significant liver fibrosis (Ishak score = 3), the mean area under the ROC curve was 0.759 ± 0.07 (p = 0.0001).

Conclusion

Measurement of ADC values by DWI was effective in detecting liver fibrosis and accurately identifying significant liver fibrosis when a b-value of 1,000 s/mm² was used.Key Words: Diffusion-weighted imaging, Hepatitis, Fibrosis, Liver     

Deep learning-based image analysis for automated measurement of eyelid morphology before and after blepharoptosis surgery

Background and aimEyelid position and contour abnormality could lead to various diseases, such as blepharoptosis, which is a common eyelid disease. Accurate assessment of eyelid morphology is important in the management of blepharoptosis. We aimed to proposed a novel deep learning-based image analysis to automatically measure eyelid morphological properties before and after blepharoptosis surgery.MethodsThis study included 135 ptotic eyes of 103 patients who underwent blepharoptosis surgery. Facial photographs were taken preoperatively and postoperatively. Margin reflex distance (MRD) 1 and 2 of the operated eyes were manually measured by a senior surgeon. Multiple eyelid morphological parameters, such as MRD1, MRD2, upper eyelid length and corneal area, were automatically measured by our deep learning-based image analysis. Agreement between manual and automated measurements, as well as two repeated automated measurements of MRDs were analysed. Preoperative and postoperative eyelid morphological parameters were compared. Postoperative eyelid contour symmetry was evaluated using multiple mid-pupil lid distances (MPLDs).ResultsThe intraclass correlation coefficients (ICCs) between manual and automated measurements of MRDs ranged from 0.934 to 0.971 (p < .001), and the bias ranged from 0.09 mm to 0.15 mm. The ICCs between two repeated automated measurements were up to 0.999 (p < .001), and the bias was no more than 0.002 mm. After surgery, MRD1 increased significantly from 0.31 ± 1.17 mm to 2.89 ± 1.06 mm, upper eyelid length from 19.94 ± 3.61 mm to 21.40 ± 2.40 mm, and corneal area from 52.72 ± 15.97 mm² to 76.31 ± 11.31mm² (all p < .001). Postoperative binocular MPLDs at different angles (from 0° to 180°) showed no significant differences in the patients.ConclusionThis technique had high accuracy and repeatability for automatically measuring eyelid morphology, which allows objective assessment of blepharoptosis surgical outcomes. Using only patients’ photographs, this technique has great potential in diagnosis and management of other eyelid-related diseases.     

Automated assessment of the remineralization of artificial enamel lesions with polarization-sensitive optical coherence tomography

Accurate measurement of the highly mineralized transparent surface layer that forms on caries lesions is important for diagnosis of the lesion activity because chemical intervention can slow or reverse the caries process via remineralization. Previous in-vitro and in-vivo studies have demonstrated that polarization-sensitive optical coherence tomography (PS-OCT) can nondestructively image the subsurface lesion structure and the highly mineralized transparent surface zone of caries lesions. The purpose of this study was to develop an approach to automatically process 3-dimensional PS-OCT images and to accurately assess the remineralization process in simulated enamel lesions. Artificial enamel lesions were prepared on twenty bovine enamel blocks using two models to produce varying degree of demineralization and remineralization. The thickness of the transparent surface layer and the integrated reflectivity of the subsurface lesion were measured using PS-OCT. The automated transparent surface layer detection algorithm was able to successfully detect the transparent surface layers with high sensitivity ( = 0.92) and high specificity ( = 0.97). The estimated thickness of the transparent surface layer showed a strong correlation with polarized light microscopy (PLM) measurements of all regions (R² = 0.90). The integrated reflectivity, ΔR, and the integrated mineral loss, ΔZ, showed a moderate correlation (R² = 0.32). This study demonstrates that PS-OCT can automatically measure the changes in artificial enamel lesion structure and severity upon exposure to remineralization solutions.OCIS codes: (170.4500) Optical coherence tomography, (170.1850) Dentistry, (170.0110) Imaging systems     

Chemopreventive Effect of Ardisia crispa Hexane Fraction on the Peri-Initiation Phase of Mouse Skin Tumorigenesis

Objective

To investigate the chemopreventive effect of the hexane extract of Ardisia crispa during the peri-initiation phase of mouse skin tumorigenesis.

Materials and Methods

This study was conducted for 12 weeks on two-stage 7,12-dimethylbenz(α)-anthracene (DMBA)-induced tumor initiation followed by croton-oil-induced tumor promotion in mice. A. crispa root hexane extract (ACRH) was applied at various doses (30, 100, 300 mg/kg) 7 days prior to and after DMBA treatment. Throughout the study, morphological observations, i.e., tumor incidence, tumor volume and tumor burden were measured for each of the treated groups. At the end of the experiment, the mice were sacrificed and their skin tissues were examined histopathologically.

Results

The highest dose of ACRH (300 mg/kg) significantly delayed tumor formation (week 9, p < 0.05) and exhibited the lowest tumor volume (0.71 ± 0.00 mm³, p < 0.05), tumor burden (2.00 ± 0.00, p < 0.05), and tumor incidence (16.67s%, p < 0.05) compared to other doses of ACRH. A 100-mg/kg dose produced tumor latency at week 7, tumor volume of 2.44 ± 0.88 mm³ (p < 0.05), tumor burden of 1.60 ± 0.60 (p < 0.05), and tumor incidence of 50s%; 30 mg/kg produced tumor latency at week 8, tumor volume of 2.04 ± 0.45 mm³ (p < 0.05), tumor burden of 2.17 ± 0.54, tumor incidence of 60s% and carcinogen control (tumor latency at week 7; tumor volume, 3.56 mm³; tumor incidence of 66.67s%).

Conclusion

The highest dose of A. crispa hexane extract delayed tumor development, thus showing a chemopreventive effect on mouse skin tumorigenesis.Key Words: Ardisia crispa, 7,12-Dimethylbenz(α)-anthracene, Tumor burden, Tumor volume     

Intercentre reproducibility of cardiac apparent diffusion coefficient and fractional anisotropy in healthy volunteers

Background

Diffusion tensor cardiac magnetic resonance (DT-CMR) enables probing of the microarchitecture of the myocardium, but the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) reported in healthy volunteers have been inconsistent. The aim of this study was to validate a stimulated-echo diffusion sequence using phantoms, and to assess the intercentre reproducibility of in-vivo diffusion measures using the sequence.

Methods and results

A stimulated-echo, cardiac-gated DT-CMR sequence with a reduced-field-of-view, single-shot EPI readout was used at two centres with 3 T MRI scanners. Four alkane phantoms with known diffusivities were scanned at a single centre using a stimulated echo sequence and a spin-echo Stejskal-Tanner diffusion sequence. The median (maximum, minimum) difference between the DT-CMR sequence and Stejskal-Tanner sequence was 0.01 (0.04, 0.0006) × 10^-3 mm²/s (2%), and between the DT-CMR sequence and literature diffusivities was 0.02 (0.05, 0.006) × 10^-3 mm²/s (4%).The same ten healthy volunteers were scanned using the DT-CMR sequence at the two centres less than seven days apart. Average ADC and FA were calculated in a single mid-ventricular, short axis slice. Intercentre differences were tested for statistical significance at the p < 0.05 level using paired t-tests. The mean ADC ± standard deviation for all subjects averaged over both centres was 1.10 ± 0.06 × 10^-3 mm²/s in systole and 1.20 ± 0.09 × 10^-3 mm²/s in diastole; FA was 0.41 ± 0.04 in systole and 0.54 ± 0.03 in diastole. With similarly-drawn regions-of-interest, systolic ADC (difference 0.05 × 10^-3 mm²/s), systolic FA (difference 0.003) and diastolic FA (difference 0.01) were not statistically significantly different between centres (p > 0.05), and only the diastolic ADC showed a statistically significant, but numerically small, difference of 0.07 × 10^-3 mm²/s (p = 0.047). The intercentre, intrasubject coefficients of variance were: systolic ADC 7%, FA 6%; diastolic ADC 7%, FA 3%.

Conclusions

This is the first study to demonstrate the accuracy of a stimulated-echo DT-CMR sequence in phantoms, and demonstrates the feasibility of obtaining reproducible ADC and FA in healthy volunteers at separate centres with well-matched sequences and processing.     

In vivo PS-OCT needle probe scan of human skeletal muscle

Polarization-sensitive optical coherence tomography (PS-OCT) derived birefringence values effectively identify skeletal muscle structural disruption due to muscular dystrophy and exercise-related muscle damage in animal models in ex vivo tissue. The purpose of this investigation was to determine if a PS-OCT needle probe inserted into the leg of a human subject could accurately identify various anatomical structures with implications for use as a diagnostic tool for the determination of skeletal muscle pathology. A healthy middle-aged subject participated in this study. A custom-built PS-OCT system was interfaced with a side-viewing fiber-optic needle probe inserted into the subject’s vastus lateralis muscle via a motorized stage for 3D data acquisition via rotation and stepwise pullback. The deepest recorded PS-OCT images correspond to a depth of 6 mm beneath the dermis with structural images showing uniform, striated muscle tissue. Multiple highly birefringent band-like structures with definite orientation representing connective tissue of the superficial aponeurosis appeared as the depth of the needle decreased. Superficial to these structures the dominating appearance was that of adipose tissue and low birefringent but homogeneous scattering tissue. The data indicate that a PS-OCT needle probe can be inserted into live human skeletal muscle for the identification of relevant anatomical structures that could be utilized to diagnose significant skeletal muscle pathology.     

Alanine aminotransferase and spleno-portal dynamics affect spleen stiffness measured by point shear-wave elastography in patients with chronic hepatitis C in the absence of significant liver fibrosis

BackgroundSpleen stiffness (SS) has gained a lot of interest in the context of liver cirrhosis and portal hypertension stratification. However, there is a paucity of data on confounding factors that may alter SS values.MethodsBetween January 2018 and October 2019, we enrolled 120 healthy subjects and 117 patients with hepatitis C virus (HCV) infection who did not have significant liver fibrosis (i.e., F0–1). Abdominal ultrasound evaluation was performed on each individual to measure portal vein diameter, portal flow velocity, spleen bipolar diameter, and splenic area. We also performed liver and spleen elastography.ResultsHCV patients had higher SS (p < 0.001), portal vein diameter (p = 0.031), portal flow velocity (p = 0.035), spleen bipolar diameter (p = 0.042) and area (p = 0.025), and ALT levels (p < 0.001). Linear regression models showed that SS increased by 3.220 kPa for each mm of portal vein diameter, by 0.7 kPa for each cm/s of portal flow velocity, by 2.239 kPa for each cm of spleen bipolar diameter, and by 0.233 kPa for each cm² of spleen area. Patients with HCV infection were stratified according to median ALT levels (i.e. 32 IU/L). SS and spleno-portal axis parameters were significantly higher in patients with an ALT level > 32 IU/L. Besides, the relationship between SS and ALT was described by cubic polynomial regression according to the following equation: 11.735 + 0.404 (ALT)¹ − 0.002 (ALT)² + 4.26 × 10^–6 (ALT)³.ConclusionsOur results bring new light to the role of inflammation as a confounding factor for SS measurement. Therefore, particular attention should be paid to serum transaminase for a correct evaluation of spleen elastography.     

Differences in carotid arterial morphology and composition between individuals with and without obstructive coronary artery disease: A cardiovascular magnetic resonance study

Objective

We sought to determine differences with cardiovascular magnetic resonance (CMR) in the morphology and composition of the carotid arteries between individuals with angiographically-defined obstructive coronary artery disease (CAD, ≥ 50% stenosis, cases) and those with angiographically normal coronaries (no lumen irregularities, controls).

Methods and results

191 participants (50.3% female; 50.8% CAD cases) were imaged with a multi-sequence, carotid CMR protocol at 1.5T. For each segment of the carotid, lumen area, wall area, total vessel area (lumen area + wall area), mean wall thickness and the presence or absence of calcification and lipid-rich necrotic core were recorded bilaterally. In male CAD cases compared to male controls, the distal bulb had a significantly smaller lumen area (60.0 ± 3.1 vs. 79.7 ± 3.2 mm², p < 0.001) and total vessel area (99.6 ± 4.0 vs. 119.8 ± 4.1 mm²; p < 0.001), and larger mean wall thickness (1.25 ± 0.03 vs. 1.11 ± 0.03 mm; p = 0.002). Similarly, the internal carotid had a smaller lumen area (37.5 ± 1.8 vs. 44.6 ± 1.8 mm²; p = 0.006) and smaller total vessel area (64.0 ± 2.3 vs. 70.9 ± 2.4 mm²; p = 0.04). These metrics were not significantly different between female groups in the distal bulb and internal carotid or for either gender in the common carotid. Male CAD cases had an increased prevalence of lipid-rich necrotic core (49.0% vs. 19.6%; p = 0.003), while calcification was more prevalent in both male (46.9% vs. 17.4%; p = 0.002) and female (33.3% vs. 14.6%; p = 0.031) CAD cases compared to controls.

Conclusion

Males with obstructive CAD compared to male controls had carotid bulbs and internal carotid arteries with smaller total vessel and lumen areas, and an increased prevalence of lipid-rich necrotic core. Carotid calcification was related to CAD status in both males and females. Carotid CMR identifies distinct morphological and compositional differences in the carotid arteries between individuals with and without angiographically-defined obstructive CAD.     

Aortic arch shape is not associated with hypertensive response to exercise in patients with repaired congenital heart diseases

Background

Aortic arch geometry is linked to abnormal blood pressure (BP) response to maximum exercise. This study aims to quantitatively assess whether aortic arch geometry plays a role in blood pressure (BP) response to exercise.

Methods

60 age- and BSA-matched subjects – 20 post-aortic coarctation (CoA) repair, 20 transposition of great arteries post arterial switch operation (ASO) and 20 healthy controls – had a three-dimensional (3D), whole heart magnetic resonance angiography (MRA) at 1.5 Tesla, 3D geometric reconstructions created from the MRA. All subjects underwent cardiopulmonary exercise test on the same day as MRA using an ergometer cycle with manual BP measurements. Geometric analysis and their correlation with BP at peak exercise were assessed.

Results

Arch curvature was similarly acute in both the post-CoA and ASO cases [0.05 ± 0.01 vs. 0.05 ± 0.01 (1/mm/m²); p = 1.0] and significantly different to that of normal healthy controls [0.05 ± 0.01 vs. 0.03 ± 0.01 (1/mm/m²), p < 0.001]. Indexed transverse arch cross sectional area were significantly abnormal in the post-CoA cases compared to the ASO cases (117.8 ± 47.7 vs. 221.3 ± 44.6; p < 0.001) and controls (117.8 ± 47.7 vs. 157.5 ± 27.2 mm²; p = 0.003). BP response to peak exercise did not correlate with arch curvature (r = 0.203, p = 0.120), but showed inverse correlation with indexed minimum cross sectional area of transverse arch and isthmus (r = -0.364, p = 0.004), and ratios of minimum arch area/ descending diameter (r = -0.491, p < 0.001).

Conclusion

Transverse arch and isthmus hypoplasia, rather than acute arch angulation plays a role in the pathophysiology of BP response to peak exercise following CoA repair.     

High resolution 3D diffusion cardiovascular magnetic resonance of carotid vessel wall to detect lipid core without contrast media

Background

Without the need of contrast media, diffusion-weighted imaging (DWI) has shown great promise for accurate detection of lipid-rich necrotic core (LRNC), a well-known feature of vulnerable plaques. However, limited resolution and poor image quality in vivo with conventional single-shot diffusion-weighted echo planar imaging (SS-DWEPI) has hindered its clinical application. The aim of this work is to develop a diffusion-prepared turbo-spin-echo (DP-TSE) technique for carotid plaque characterization with 3D high resolution and improved image quality.

Methods

Unlike SS-DWEPI where the diffusion encoding is integrated in the EPI framework, DP-TSE uses a diffusion encoding module separated from the TSE framework, allowing for segmented acquisition without the sensitivity to phase errors. The interleaved, motion-compensated sequence was designed to enable 3D black-blood DWI of carotid arteries with sub-millimeter resolution. The sequence was tested on 12 healthy subjects and compared with SS-DWEPI for image quality, vessel wall visibility, and vessel wall thickness measurements. A pilot study was performed on 6 patients with carotid plaques using this sequence and compared with conventional contrast-enhanced multi-contrast 2D TSE as the reference.

Results

DP-TSE demonstrated advantages over SS-DWEPI for resolution and image quality. In the healthy subjects, vessel wall visibility was significantly higher with diffusion-prepared TSE (p < 0.001). Vessel wall thicknesses measured from diffusion-prepared TSE were on average 35% thinner than those from the EPI images due to less distortion and partial volume effect (p < 0.001). ADC measurements of healthy carotid vessel wall are 1.53 ± 0.23 × 10⁻³ mm²/s. In patients the mean ADC measurements in the LRNC area were significantly lower (0.60 ± 0.16 × 10⁻³ mm²/s) than those of the fibrous plaque tissue (1.27 ± 0.29 × 10⁻³ mm²/s, p < 0.01).

Conclusions

Diffusion-prepared CMR allows, for the first time, 3D DWI of the carotid arterial wall in vivo with high spatial resolution and improved image quality over SS-DWEPI. It can potentially detect LRNC without the use of contrast agents, allowing plaque characterization in patients with renal insufficiency.

Electronic supplementary material

The online version of this article (doi:10.1186/s12968-014-0067-z) contains supplementary material, which is available to authorized users.     

Leveraging high-resolution 7-tesla MRI to derive quantitative metrics for the trigeminal nerve and subnuclei of limbic structures in trigeminal neuralgia

BackgroundTrigeminal Neuralgia (TN) is a chronic neurological disease that is strongly associated with neurovascular compression (NVC) of the trigeminal nerve near its root entry zone. The trigeminal nerve at the site of NVC has been extensively studied but limbic structures that are potentially involved in TN have not been adequately characterized. Specifically, the hippocampus is a stress-sensitive region which may be structurally impacted by chronic TN pain. As the center of the emotion-related network, the amygdala is closely related to stress regulation and may be associated with TN pain as well. The thalamus, which is involved in the trigeminal sensory pathway and nociception, may play a role in pain processing of TN. The objective of this study was to assess structural alterations in the trigeminal nerve and subregions of the hippocampus, amygdala, and thalamus in TN patients using ultra-high field MRI and examine quantitative differences in these structures compared with healthy controls.MethodsThirteen TN patients and 13 matched controls were scanned at 7-Tesla MRI with high resolution, T1-weighted imaging. Nerve cross sectional area (CSA) was measured and an automated algorithm was used to segment hippocampal, amygdaloid, and thalamic subregions. Nerve CSA and limbic structure subnuclei volumes were compared between TN patients and controls.ResultsCSA of the posterior cisternal nerve on the symptomatic side was smaller in patients (3.75 mm²) compared with side-matched controls (5.77 mm², p = 0.006). In TN patients, basal subnucleus amygdala volume (0.347 mm³) was reduced on the symptomatic side compared with controls (0.401 mm³, p = 0.025) and the paralaminar subnucleus volume (0.04 mm³) was also reduced on the symptomatic side compared with controls (0.05 mm³, p = 0.009). The central lateral thalamic subnucleus was larger in TN patients on both the symptomatic side (0.033 mm³) and asymptomatic side (0.035 mm³), compared with the corresponding sides in controls (0.025 mm³ on both sides, p = 0.048 and p = 0.003 respectively). The inferior and lateral pulvinar thalamic subnuclei were both reduced in TN patients on the symptomatic side (0.2 mm³ and 0.17 mm³ respectively) compared to controls (0.23 mm³, p = 0.04 and 0.18 mm³, p = 0.04 respectively). No significant findings were found in the hippocampal subfields analyzed.ConclusionsThese findings, generated through a highly sensitive 7 T MRI protocol, provide compelling support for the theory that TN neurobiology is a complex amalgamation of local structural changes within the trigeminal nerve and structural alterations in subnuclei of limbic structures directly and indirectly involved in nociception and pain processing.Supplementary InformationThe online version contains supplementary material available at 10.1186/s10194-021-01325-4.     

Epoxy-α-Lapachone Has In Vitro and In Vivo Anti-Leishmania (Leishmania) amazonensis Effects and Inhibits Serine Proteinase Activity in This Parasite

Leishmania (Leishmania) amazonensis is a protozoan that causes infections with a broad spectrum of clinical manifestations. The currently available chemotherapeutic treatments present many problems, such as several adverse side effects and the development of resistant strains. Natural compounds have been investigated as potential antileishmanial agents, and the effects of epoxy-α-lapachone on L. (L.) amazonensis were analyzed in the present study. This compound was able to cause measurable effects on promastigote and amastigote forms of the parasite, affecting plasma membrane organization and leading to death after 3 h of exposure. This compound also had an effect in experimentally infected BALB/c mice, causing reductions in paw lesions 6 weeks after treatment with 0.44 mM epoxy-α-lapachone (mean lesion area, 24.9 ± 2.0 mm²), compared to untreated animals (mean lesion area, 30.8 ± 2.6 mm²) or animals treated with Glucantime (mean lesion area, 28.3 ± 1.5 mm²). In addition, the effects of this compound on the serine proteinase activities of the parasite were evaluated. Serine proteinase-enriched fractions were extracted from both promastigotes and amastigotes and were shown to act on specific serine proteinase substrates and to be sensitive to classic serine proteinase inhibitors (phenylmethylsulfonyl fluoride, aprotinin, and antipain). These fractions were also affected by epoxy-α-lapachone. Furthermore, in silico simulations indicated that epoxy-α-lapachone can bind to oligopeptidase B (OPB) of L. (L.) amazonensis, a serine proteinase, in a manner similar to that of antipain, interacting with an S1 binding site. This evidence suggests that OPB may be a potential target for epoxy-α-lapachone and, as such, may be related to the compound''s effects on the parasite.     

Ultrafast laser surgery probe with a calcium fluoride miniaturized objective for bone ablation

We present a miniaturized ultrafast laser surgery probe with improved miniaturized optics to deliver higher peak powers and enable higher surgical speeds than previously possible. A custom-built miniaturized CaF₂ objective showed no evidence of the strong multiphoton absorption observed in our previous ZnS-based probe, enabling higher laser power delivery to the tissue surface for ablation. A Kagome fiber delivered ultrashort pulses from a high repetition rate fiber laser to the objective, producing a focal beam radius of 1.96 μm and covering a 90×90 μm² scan area. The probe delivered the maximum available fiber laser power, providing fluences >6 J/cm² at the tissue surface at 53% transmission efficiency. We characterized the probe’s performance through a parametric ablation study on bovine cortical bone and defined optimal operating parameters for surgery using an experimental- and simulation-based approach. The entire opto-mechanical system, enclosed within a 5-mm diameter housing with a 2.6-mm diameter probe tip, achieved material removal rates >0.1 mm³/min, however removal rates were ultimately limited by the available laser power. Towards a next generation surgery probe, we simulated maximum material removal rates when using a higher power fiber laser and found that removal rates >2 mm³/min could be attained through appropriate selection of laser surgery parameters. With future development, the device presented here can serve as a precise surgical tool with clinically viable speeds for delicate applications such as spinal decompression surgeries.     

An aqueous phase TEMPO mediated electrooxidation of 2-thiophenemethanol using MnO2–Pi dispersed nanocarbon spheres on a carbon fiber paper electrode

An environmentally benign and economic method was developed for the electrocatalytic oxidation of 2-thiophenemethanol in an aqueous acidic medium. Nanocarbon spheres (NCS) coated on carbon fiber paper (CFP) were used as a host matrix to disperse manganese dioxide nanoparticles from phosphate buffer solution through electrochemical deposition. The developed electrode (MnO₂–Pi–NCS/CFP) was used as a working electrode for electrochemical oxidation of 2-thiophenemethanol in the presence of a mediator TEMPO in 0.01 M H₂SO₄ medium. Different analytical methods were used to characterize the modified electrodes. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to study the electrochemical properties of the modified electrodes. The electrochemically active surface area values calculated for bare CFP, NCS coated CFP and MnO₂–Pi–NCS/CFP electrodes were found to be 1.43 cm², 2.86 cm², and 6.72 cm² respectively for the geometric area of 0.7 cm² of the electrodes. Coating of NCS and MnO₂–Pi resulted in porosity and roughness of the CFP electrode which enhances the surface area. MnO₂–Pi–NCS/CFP demonstrated higher electrocatalytic activity for oxidation of 2-thiophenemethanol to 2-thiophenemethanal in aqueous acidic media with a TEMPO mediator compared to unmodified electrodes.

An environmentally benign and economic method was developed for the electrocatalytic oxidation of 2-thiophenemethanol in an aqueous acidic medium.     

The value of sonographic quantitative parameters in the diagnosis of carpal tunnel syndrome in the Vietnamese population

ObjectiveTo examine the value of ultrasound (US) in the diagnosis of carpal tunnel syndrome (CTS) in the Vietnamese population.MethodsThis prospective cross-sectional study involved 42 wrists of 25 patients with idiopathic CTS evaluated by US. In addition, 38 wrists of 22 healthy volunteers were included as the control group.ResultsSignificant differences in the median nerve cross-sectional area (CSA) at different levels were found between patients with CTS and controls. Using a cut-off value of 9.5 mm² for the median nerve CSA at the pisiform (p-CSA), US had a sensitivity and specificity of 95.2% and 97.4%, respectively, for the diagnosis of CTS. Area under the curve analysis revealed a sensitivity and specificity of 100% and 95.4%, respectively, for the prediction of severe CTS using a p-CSA of >15.5 mm².ConclusionsThe median nerve CSA is a highly accurate parameter in the diagnosis of CTS. We recommend using a p-CSA of >9.5 mm² as a diagnostic criterion for CTS and a p-CSA of >15.5 mm² as a marker for severe CTS in the Vietnamese population.Research Registry number: 7261     

Delivering stem cells to the healthy heart on biological sutures: effects on regional mechanical function

Current cardiac cell therapies cannot effectively target and retain cells in a specific area of the heart. Cell‐seeded biological sutures were previously developed to overcome this limitation, demonstrating targeted delivery with > 60% cell retention. In this study, both cell‐seeded and non‐seeded fibrin‐based biological sutures were implanted into normal functioning rat hearts to determine the effects on mechanical function and fibrotic response. Human mesenchymal stem cells (hMSCs) were used based on previous work and established cardioprotective effects. Non‐seeded or hMSC‐seeded sutures were implanted into healthy athymic rat hearts. Before cell seeding, hMSCs were passively loaded with quantum dot nanoparticles. One week after implantation, regional stroke work index and systolic area of contraction (SAC) were evaluated on the epicardial surface above the suture. Cell delivery and retention were confirmed by quantum dot tracking, and the fibrotic tissue area was evaluated. Non‐seeded biological sutures decreased SAC near the suture from 0.20 ± 0.01 measured in sham hearts to 0.08 ± 0.02, whereas hMSC‐seeded biological sutures dampened the decrease in SAC (0.15 ± 0.02). Non‐seeded sutures also displayed a small amount of fibrosis around the sutures (1.0 ± 0.1 mm²). Sutures seeded with hMSCs displayed a significant reduction in fibrosis (0.5 ± 0.1 mm², p < 0.001), with quantum dot‐labelled hMSCs found along the suture track. These results show that the addition of hMSCs attenuates the fibrotic response observed with non‐seeded sutures, leading to improved regional mechanics of the implantation region. Copyright © 2014 John Wiley & Sons, Ltd.     

Comparison of symptomatic and asymptomatic atherosclerotic carotid plaques using parallel imaging and 3?T black-blood in vivo CMR

Background

To determine if black-blood 3 T cardiovascular magnetic resonance (bb-CMR) can depict differences between symptomatic and asymptomatic carotid atherosclerotic plaques in acute ischemic stroke patients.

Methods

In this prospective monocentric observational study 34 patients (24 males; 70 ±9.3 years) with symptomatic carotid disease defined as ischemic brain lesions in one internal carotid artery territory on diffusion weighted images underwent a carotid bb-CMR at 3 T with fat-saturated pre- and post-contrast T1w-, PDw-, T2w- and TOF images using surface coils and Parallel Imaging techniques (PAT factor = 2) within 10 days after symptom onset. All patients underwent extensive clinical workup (lab, brain MR, duplex sonography, 24-hour ECG, transesophageal echocardiography) to exclude other causes of ischemic stroke. Prevalence of American Heart Association lesion type VI (AHA-LT6), status of the fibrous cap, presence of hemorrhage/thrombus and area measurements of calcification, necrotic core and hemorrhage were determined in both carotid arteries in consensus by two reviewers who were blinded to clinical information. McNemar and Wilcoxon''s signed rank tests were use for statistical comparison. A p-value <0.05 was considered statistically significant.

Results

Symptomatic plaques showed a higher prevalence of AHA-LT6 (67.7% vs. 11.8%; p < 0.001; odds ratio = 12.5), ruptured fibrous caps (44.1% vs. 2.9%; p < 0.001; odds ratio = 15.0), juxtaluminal thrombus (26.5 vs. 0%; p < 0.01; odds ratio = 7.3) and intraplaque hemorrhage (58.6% vs. 11.8%; p = 0.01; odds ratio = 3.8). Necrotic core and hemorrhage areas were greater in symptomatic plaques (14.1 mm² vs. 5.5 mm² and 13.6 mm² vs. 5.3 mm²; p < 0.01, respectively).

Conclusion

3 T bb-CMR is able to differentiate between symptomatic and asymptomatic carotid plaques, demonstrating the potential of bb-CMR to differentiate between stable and vulnerable lesions and ultimately to identify patients with low versus high risk for cardiovascular complications. Best predictors of the symptomatic side were a ruptured fibrous cap, AHA-LT 6, juxtaluminal hemorrhage/thrombus, and intraplaque hemorrhage.     

Cardiovascular magnetic resonance for the assessment of patients undergoing transcatheter aortic valve implantation: a pilot study

Background

Before trans-catheter aortic valve implantation (TAVI), assessment of cardiac function and accurate measurement of the aortic root are key to determine the correct size and type of the prosthesis. The aim of this study was to compare cardiovascular magnetic resonance (CMR) and trans-thoracic echocardiography (TTE) for the assessment of aortic valve measurements and left ventricular function in high-risk elderly patients submitted to TAVI.

Methods

Consecutive patients with severe aortic stenosis and contraindications for surgical aortic valve replacement were screened from April 2009 to January 2011 and imaged with TTE and CMR.

Results

Patients who underwent both TTE and CMR (n = 49) had a mean age of 80.8 ± 4.8 years and a mean logistic EuroSCORE of 14.9 ± 9.3%. There was a good correlation between TTE and CMR in terms of annulus size (R² = 0.48, p < 0.001), left ventricular outflow tract (LVOT) diameter (R² = 0.62, p < 0.001) and left ventricular ejection fraction (LVEF) (R² = 0.47, p < 0.001) and a moderate correlation in terms of aortic valve area (AVA) (R² = 0.24, p < 0.001). CMR generally tended to report larger values than TTE for all measurements. The Bland-Altman test indicated that the 95% limits of agreement between TTE and CMR ranged from -5.6 mm to + 1.0 mm for annulus size, from -0.45 mm to + 0.25 mm for LVOT, from -0.45 mm² to + 0.25 mm² for AVA and from -29.2% to 13.2% for LVEF.

Conclusions

In elderly patients candidates to TAVI, CMR represents a viable complement to transthoracic echocardiography.     

Effects of experimental heart failure on the capacity of glucagon to augment myocardial contractility and activate adenyl cyclase

Although glucagon exerts positive inotropic effects in patients with no or mild impairment of cardiac function, similar effects are not consistently observed in patients with chronic heart failure. Accordingly, the inotropic effects of glucagon on papillary muscles from normal cats and cats in which right ventricular failure had been produced for 4-145 days by pulmonary artery banding were compared. At the peak of the concentration-response curve, glucagon increased peak isometric tension (T) in normal muscles from 4.4±0.4 to 6.6±0.5 g/mm² (P <0.001), and maximum rate of tension development (dT/dt) from 16.9±0.9 to 25.1±1.6 g/sec per mm² (P < 0.001). In contrast, glucagon produced no significant increases in T or dT/dt in failure muscles. The percentage increases in T and dT/dt caused by norepinephrine were the same in muscles from normal and failing hearts. Since the cardiac effects of glucagon and norepinephrine may be mediated by adenyl cyclase, responsiveness of adenyl cyclase was determined in particulate fractions of the right ventricle. Glucagon activated adenyl cyclase in normal, but had no effect in failure preparations. Norepinephrine-induced activation of adenyl cyclase, however, was unaltered by failure. Thus, in contrast to norepinephrine, glucagon loses the capacity to augment myocardial contractility and activate adenyl cyclase in hearts derived from cats in chronic failure.     

Mesenchymal stem cells administered in the early phase of tumorigenesis inhibit colorectal tumor development in rats

To investigate the differences between the effects of mesenchymal stem cells (MSCs) administered in the early and late phases of tumorigenesis, MSCs were isolated from bone marrow and colorectal tumors were produced by exposing 7-week-old F344 rats to 1,2-dimethylhydrazine and dextran sulfate sodium. We evaluated tumor number and volume (week 25), MSC localization, number of aberrant crypt foci (ACF), transforming growth factor (TGF)-β1 protein levels in the rectum after administration of MSCs (week 5 or 15), and the effects of MSC-conditioned medium on ACL15 cell proliferation. Administered MSCs labeled with PKH26 were observed in the rectum. Administered MSCs in the early phase (week 5) before tumor occurrence (week 12) significantly decreased tumor number and volume (1.5 vs 4 and 21 mm³ vs 170 mm³; p<0.01), but not administered MSCs in the late phase (week 15). Administered MSCs in the early phase reduced ACF number on days 14 and 35 (1.9 vs 4.1 and 3.7 vs 7.3; p<0.01). Rectal TGF-β1 increased 1.3 fold on day 3, and MSC-conditioned medium containing TGF-β1 abundantly inhibited ACL15 cell proliferation. MSCs administered in the early phase but not late phase inhibited colorectal tumor development in a rat model.