Evaluation of biomechanical and histological properties of corrosive chemical burns

This study was aimed to prepare a standard experimental chemical burns and evaluate biomechanical and histological properties. As a model corrosive acid burns, sulfuric acid burns were made on the peritoneal part of the rabbit ear with diameter 8?mm by varing sulfuric acid concentrations (1, 2, 18.8?M) and inflicted time (20, 40, 60 and 120?s). The progress of the chemical injury was evaluated for 3?weeks by macroscopic and microscopic observation. Degree of regeneration of damaged epidermis and dermis and presence of infected cells and arrangements of collagen were investigated. Histology of 18.8?M sulfuric acid for 20?s burns showed epidermal necrosis, diffuse vascular infiltrate and collagen degeneration at the level of the papillary dermis, which is a characteristic of a deep dermal burn. The stress?Cstrain curves of normal skin, 18.8?M sulfuric acid treated wound, 6?mm surgical biopsy punch wound and at 21?days post wound were evaluated. As tensile strength measures the ability of matrix to withstand rupture, as the damage from corrosive acid chemical involved wider and deep skin area with permanent damage, the healing could not be processed complete and showed less than 16?% of tensile strength (0.05?±?0.01?N/mm²) as compared with those of normal skin (0.31?±?0.08?N/mm²). The sulfuric acid inflicted wound showed flatter, reflecting the small magnitude of their moduli of elasticity. The elasticity constant for sulfuric acid treated skin (1.46?±?0.17?N/mm) is only 25?% of those of normal skin (5.87?±?2.14?N/mm). Surgical punch wound showed higher tensile strength (0.10?±?0.02?N/mm²) and elasticity constant (4.19?±?0.47?N/mm) than those of corrosive chemical acid burns. In conclusion, the proposed sulfuric acid burn condition (18.8?M, 20?s) could be employed as a useful corrosive chemical wound model. The degree of damage induced by corrosive acid chemicals is more significant than surgical full thickness wound and was dependent on the concentration and treatment time. By controlling the burn condition, the extent of damage could be designed. Biomechanical and histological study demonstrated that the corrosive acid burns induced full thickness permanent dermal injury and significant losses in tensile strength and elasticity modulus.     

Practical Application of Iterative Decomposition of Water and Fat with Echo Asymmetry and Least-Squares Estimation (IDEAL) Imaging in Minimizing Metallic Artifacts

Iterative decomposition of water and fat with echo asymmetry and the least-squares estimation (IDEAL) is a recently developed method for robust separation of fat and water with very high signal-to-noise-ratio (SNR) efficiency. In contrast to conventional fat-saturation methods, IDEAL is insensitive to magnetic field (B0 and B1) inhomogeneity. The aim of this study was to illustrate the practical application of the IDEAL technique in reducing metallic artifacts in postoperative patients with metallic hardware. The IDEAL technique can help musculoskeletal radiologists make an accurate diagnosis particularly in musculoskeletal imaging by reducing metallic artifacts, enabling the use of contrast enhancement, improving SNR performance, and providing various modes of MR images with one scan parameter.     

(−)-Epigallocatechin-3-gallate inhibits voltage-gated proton currents in BV2 microglial cells

(?)-Epigallocatechin-3-gallate (EGCG), the principal constituent of green tea, protects neurons from toxic insults by suppressing the microglial secretion of neurotoxic inflammatory mediators. Voltage-gated proton channels are expressed in microglia, and are required for NADPH oxidase-dependent reactive oxygen species generation. Brain damage after ischemic stroke is dependent on proton channel activity. Accordingly, we examined whether EGCG could inhibit proton channel function in the murine microglial BV2 cells. EGCG potently inhibited proton currents with an IC₅₀ of 3.7 μM. Other tea catechins, (?)-epigallocatechin, (?)-epicatechin and (?)-epicatechin-3-gallate, were far less potent than EGCG. EGCG did not change the kinetics of proton currents such as the activation and the deactivation time constants, the reversal potential and the activation voltage, suggesting that the gating process of proton channels were not altered by EGCG. EGCG is known to disturb lipid rafts by sequestering cholesterol. However, neither extraction of cholesterol with methyl-β-cyclodextrin or cholesterol supplementation could reverse the EGCG inhibition of proton currents. In addition, the EGCG effect was preserved in the presence of the cytoskeletal stabilizers paclitaxel and phalloidin, phosphatase inhibitors, the antioxidant Trolox, superoxide dismutase or catalase. The proton channel inhibition can be a substantial mechanism for EGCG to suppress microglial activation and subsequent neurotoxic events.     

Surgical Outcomes of Canalicular Trephination Combined with Endoscopic Dacryocystorhinostomy in Patients with Distal or Common Canalicular Obstruction

PurposeThis study investigated the surgical outcomes of canalicular trephination combined with endoscopic dacryocystorhinostomy (DCR) in patients with a distal or common canalicular obstruction. It also identified the factors affecting surgical success rates associated with this technique.MethodsWe retrospectively reviewed the medical records of 57 patients (59 eyes) in whom a canalicular obstruction was encountered during endoscopic DCR. All patients were treated with endoscopic DCR, followed by canalicular trephination and silicone tube placement. The surgical outcome was categorized as a functional success according to the patient''s subjective assessment of symptoms, including epiphora, and as an anatomical success according to a postoperative nasolacrimal duct irrigation test. Surgical success rates were compared based on age, sex, location of the obstruction, number of silicone tubes, and experience of the surgeon.ResultsFunctional success was achieved in 55 of 59 eyes (93%) at one month, 50 eyes (84%) at three months, and 46 eyes (78%) at six months. Anatomical success was achieved in 58 of 59 eyes (98%) at one month, 52 eyes (88%) at three months, and 50 eyes (84%) at six months. There was a statistically significant difference in surgical outcome according to the experience of the surgeon. The anatomical success rate at the six-month follow-up exam was 95.4% in the >5 years of experience group, and 53.3% in the <5 years of experience group (p = 0.008, Pearson chi-square test).ConclusionsThe success rate of canalicular trephination combined with endoscopic DCR in patients with a distal or common canalicular obstruction decreased gradually during the six-month follow-up period. In particular, patients undergoing procedures with experienced surgeons tended to show excellent surgical outcomes at the six-month follow-up exam.     

Evaluation of the angiographic outcomes after clipping of intracranial aneurysms: determination of predisposing factors for occurrence of aneurysm remnants

ABSTRACT

Objectives: Aneurysm remnants after microsurgical clipping have a risk of regrowth and rupture and have not been validated in the era of three-dimensional angiography. Therefore, this study aimed to evaluate the angiographic outcome using three-dimensional rotational images and determine the predictors for remnants after microsurgical clipping.

Methods: Between January 2014 and May 2017, 139 aneurysms in 106 patients who were treated with microsurgical clipping, were eligible for this study. For the determination of aneurysm remnants after microsurgical clipping, the angiographic outcomes were evaluated using follow-up digital subtraction angiography within 7 days for unruptured aneurysms or within 2 weeks for ruptured aneurysms. According to the Sindou classification, the aneurysm remnants were dichotomized, and subgroup analysis was performed to identify the predictors of aneurysm remnants after clipping with various imaging parameters and clinical information.

Results: The overall rate of aneurysm remnants was 29.5% (41/139), in which retreatments were needed in 6.5% (9/139). The neck size and maximum diameter of aneurysms were independent predisposing factors for the aneurysm remnants that need retreatment (OR: 2.30; p < 0.001; OR: 1.38; p < 0.001, respectively).

Conclusions: This study demonstrated a low incidence of aneurysm remnants after microsurgical clipping which need to retreatment. However, selective postoperative angiography could provide us clear information of surgical result and evidence for long-term follow-up for some aneurysms with larger neck size (>5.7 mm) and maximum diameter (>7.1 mm).     

Automated MRI-based classification of primary progressive aphasia variants

Degeneration of language regions in the dominant hemisphere can result in primary progressive aphasia (PPA), a clinical syndrome characterized by progressive deficits in speech and/or language function. Recent studies have identified three variants of PPA: progressive non-fluent aphasia (PNFA), semantic dementia (SD) and logopenic progressive aphasia (LPA). Each variant is associated with characteristic linguistic features, distinct patterns of brain atrophy, and different likelihoods of particular underlying pathogenic processes, which makes correct differential diagnosis highly clinically relevant. Evaluation of linguistic behavior can be challenging for non-specialists, and neuroimaging findings in single subjects are often difficult to evaluate by eye. We investigated the utility of automated structural MR image analysis to discriminate PPA variants (N = 86) from each other and from normal controls (N = 115). T1 images were preprocessed to obtain modulated grey matter (GM) images. Feature selection was performed with principal components analysis (PCA) on GM images as well as images of lateralized atrophy. PC coefficients were classified with linear support vector machines, and a cross-validation scheme was used to obtain accuracy rates for generalization to novel cases. The overall mean accuracy in discriminating between pairs of groups was 92.2%. For one pair of groups, PNFA and SD, we also investigated the utility of including several linguistic variables as features. Models with both imaging and linguistic features performed better than models with only imaging or only linguistic features. These results suggest that automated methods could assist in the differential diagnosis of PPA variants, enabling therapies to be targeted to likely underlying etiologies.     

Family history of diabetes and risk of atherosclerotic cardiovascular disease in Korean men and women

The importance of family history of type 2 diabetes (FHD) as a risk factor for atherosclerotic cardiovascular disease (ASCVD) remains controversial. A report of diabetes in parents and siblings was used to establish FHD in a cohort of 1,005,230 Koreans aged 30-95 years insured by the National Health Insurance Corporation who had a biennial medical evaluation during 1992-1995. ASCVD morbidity and mortality from 1993 to 2005 were examined in relation to FHD and other ASCVD risk factors. The risk of ischemic heart disease (IHD) increased significantly (19%) in men with FHD but not in women. A strong interaction was observed between FHD and personal history of diabetes for the occurrence of ASCVD; men with both diabetes and FHD were at significantly increased risk of developing IHD, cerebrovascular disease and ASCVD with hazard ratios (HR) of 2.28, 2.07, and 2.12, respectively, compared to those who had neither FHD nor type 2 diabetes. Corresponding risks were 2.64, 2.03, and 2.10 in women, respectively. This study demonstrates that risk of ASCVD is increased among those with diabetes and a family history of diabetes; suggesting that genetic factors associated with occurrence of familial diabetes may increase risk of ASCVD beyond the risk among people without FHD.