Hyperattenuating lesions after mechanical thrombectomy in acute ischaemic stroke: factors predicting symptomatic haemorrhage and clinical outcomes.

AIM: To evaluate the clinical significance of hyperattenuating lesions on CT after mechanical thrombectomy for acute ischaemic stroke, and to identify imaging factors that predict symptomatic haemorrhage and unfavourable outcomes. MATERIALS AND METHODS: Seventy-eight patients with acute ischaemic stroke in the anterior circulation who underwent mechanical thrombectomy were evaluated. All patients underwent post-interventional unenhanced computed tomography (CT) within 24 h and follow-up CT or magnetic resonance imaging (MRI) within 7 days. Baseline characteristics and clinical outcomes were compared between patients with and without hyperattenuating lesions. In patients with hyperattenuating lesions, clinical and imaging factors that predict symptomatic haemorrhage and unfavourable outcomes were determined. RESULTS: Fifty-six of 78 patients (71.8%) demonstrated hyperattenuating lesions on post-interventional CT. Patients with hyperattenuating lesions showed lower Alberta Stroke Program Early CT score (ASPECTS), persistent/symptomatic haemorrhage, and unfavourable outcomes than those without. In patients with hyperattenuating lesions, larger hyperattenuating lesion volume (>21.3 ml; OR, 55.60, p<0.001) and perilesional oedema (OR, 46.04, p=0.015) were independent factors predicting symptomatic haemorrhage. Older age (OR, 1.2, p=0.006) and lower ASPECTS (OR, 0.45, p=0.046) were independent factors predicting unfavourable outcomes in patients with hyperattenuating lesions. Adding the volume of the hyperattenuating lesion to age and ASPECTS increased the predictive performance of unfavourable outcomes (area under the curve 0.874 versus 0.934, p=0.043). CONCLUSIONS: Hyperattenuating lesions on post-interventional CT are associated with increased risk of symptomatic haemorrhage and unfavourable outcomes. Larger hyperattenuating lesion volume is an independent factor of symptomatic haemorrhage and it has added predictive value for unfavourable outcomes.

Therapeutic advantage of genetically engineered Salmonella typhimurium carrying short hairpin RNA against inhibin alpha subunit in cancer treatment.

Background: In contrast to its well-known endocrine function, the role of inhibin in cancer development and therapeutic response is unclear. Salmonella, particularly less toxic attenuated Salmonella strains, are used to treat cancer in two ways. First, Salmonella accumulate around tumors, penetrate the cell barrier, and replicate inside the tumors. Second, Salmonella can act as a vehicle for delivering anticancer agents or proapoptotic genes to attack tumors. In this study, we aimed to develop a suitable cancer therapeutic strategy by genetically modifying attenuated Salmonella typhimurium to harbor short hairpin RNA (shRNA) expression plasmids targeting alpha subunit of inhibin (sh-INHA). Methods: We analyzed the expression of human INHA in normal and cancer cells and tissues. We developed genetically engineered attenuated S. typhimurium harboring sh-INHA (S. typhimurium/sh-INHA) and assessed its cancer therapeutic effects by using cell culture models and syngeneic mouse tumor models. Results: INHA expression levels were markedly higher in colon cancer and melanoma cells and tissues than in their normal counterparts. Suppression of INHA expression mildly reduced cancer cell survival and induced caspase activation and downregulation of anti-apoptotic Bcl-2 and Bcl-xL expressions. Although the genetically engineered S. typhimurium mildly interfered with the invasion of S. typhimurium into host colon cancer and melanoma cells, S. typhimurium/sh-INHA caused remarkable cytotoxicity in cancer compared with unmodified S. typhimurium or S. typhimurium expressing a control scrambled shRNA (S. typhimurium/sh-Cont). Salmonella typhimurium/sh-INHA-treated mice also showed a significantly inhibited growth of colon cancers and melanomas, with a survival advantage. Conclusion: Our results suggest that tumor-targeted therapy using S. typhimurium/sh-INHA may provide a novel cancer treatment option.

Development of a stiffness-angle law for simplifying the measurement of human hair stiffness.

OBJECTIVE: This research examines the benefits of caffeine absorption on hair stiffness. To test hair stiffness, we have developed an evaluation method that is not only accurate, but also inexpensive. Our evaluation method for measuring hair stiffness culminated in a model, called the Stiffness-Angle Law, which describes the elastic properties of hair and can be widely applied to the development of hair care products. METHODS: Small molecules (≤500 g mol-1 ) such as caffeine can be absorbed into hair. A common shampoo containing 4% caffeine was formulated and applied to hair 10 times, after which the hair stiffness was measured. The caffeine absorption of the treated hair was observed using Fourier-transform infrared spectroscopy (FTIR) with a focal plane array (FPA) detector. Our evaluation method for measuring hair stiffness consists of a regular camera and a support for single strands of hair. After attaching the hair to the support, the bending angle of the hair was observed with a camera and measured. Then, the hair strand was weighed. The stiffness of the hair was calculated based on our proposed Stiffness-Angle Law using three variables: angle, weight of hair and the distance the hair was pulled across the support. RESULTS: The caffeine absorption was confirmed by FTIR analysis. The concentration of amide bond in the hair certainly increased due to caffeine absorption. After caffeine was absorbed into the hair, the bending angle and weight of the hair changed. Applying these measured changes to the Stiffness-Angle Law, it was confirmed that the hair stiffness increased by 13.2% due to caffeine absorption. CONCLUSION: The theoretical results using the Stiffness-Angle Law agree with the visual examinations of hair exposed to caffeine and also the known results of hair stiffness from a previous report. Our evaluation method combined with our proposed Stiffness-Angle Law effectively provides an accurate and inexpensive evaluation technique for measuring bending stiffness of human hair.

The analysis of scalp irritation by coacervates produced in hair shampoo via FTIR with focal plane array detector, X-ray photoelectron microscopy and HaCaT cells.

OBJECTIVE: Coacervates are inevitably formed on scalp on using hair washing products. Our goal was to analyse the coacervates in detail to identify the part responsible for scalp stimulation. METHODS: Shampoo that increases coacervate formation was applied to in vitro skin and was washed. The residue was then analysed using Fourier transform infrared spectroscopy-focal plane array (FTIR-FPA) and X-ray photoelectron microscopy (XPS). And HaCaT cells were used for irritant test of coacervate. RESULTS: Through this research, it was confirmed that the coacervate was a macromolecule structurally similar to a cationic polymer and contains an anionic surfactant. Its anionic surfactant was structurally semi-stable so that it released onto scalp when it absorbs moisture. CONCLUSION: Coacervate releases sulphate bonding into the matrix when it is exposed to water. Thus, the scalp stimulation would be expected.

Conservation of Hox gene clusters in the self-fertilizing fish Kryptolebias marmoratus (Cyprinodontiformes; Rivulidae).

In this study, whole Hox gene clusters in the self-fertilizing mangrove killifish Kryptolebias marmoratus (Cyprinodontiformes; Rivulidae), a unique hermaphroditic vertebrate in which both sex organs are functional at the same time, were identified from whole genome and transcriptome sequences. The aim was to increase the understanding of the evolutionary status of conservation of this Hox gene cluster across fish species.

Comparison of stent retriever and intra-arterial fibrinolysis in patients with acute ischaemic stroke.

BACKGROUND AND PURPOSE: Although the stent retriever (SR) has shown a better reperfusion rate and clinical outcome than the older generation mechanical clot retrieval device, it is uncertain whether the SR is superior to intra-arterial fibrinolysis (IAF). METHODS: Ischaemic stroke patients who were treated with SR or IAF as initial endovascular treatment modality for unilateral arterial occlusion in the anterior circulation were included. Successful reperfusion was defined as Thrombolysis in Cerebral Infarction grade ≥2b. A favourable clinical outcome was defined as a modified Rankin Score ≤2 at 3 months. RESULTS: Between January 2009 and May 2012, 55 patients were treated with SR and 50 patients were treated with IAF. The baseline characteristics were similar between the two groups except for the occlusion site and rescue treatment. In binary logistic regression analysis adjusted for the occlusion site and rescue treatment, SR was independently associated with increased successful reperfusion [82.0% vs. 47.3%; odds ratio (OR) 5.21; 95% confidence interval (CI) 1.92-14.14) and a more favourable clinical outcome at 3 months (54.0% vs. 43.6%; OR 3.40; 95% CI 1.31-8.84). The frequency of symptomatic intracranial haemorrhage and mortality at 3 months was not different between the two groups. CONCLUSIONS: Stent retriever was as safe as and more effective than IAF. Our findings suggest that SR may be considered as an initial modality rather than IAF in acute stroke patients who undergo endovascular treatment.

Genome-wide association analysis identifies quantitative trait loci for growth in a Landrace purebred population.

Growth-related traits are complex and economically important in the livestock industry. The aim of this study was to identify quantitative trait loci (QTL) and the associated positional candidate genes affecting growth in pigs. A genome-wide association study (GWAS) was performed using the porcine single-nucleotide polymorphism (SNP) 60K bead chip. A mixed-effects model and linear regression approach were used for the GWAS. The data used in the study included 490 purebred Landrace pigs. All experimental animals were genotyped with 39 438 SNPs located throughout the pig autosomes. We identified a strong association between a SNP marker on chromosome 16 and body weight at 71 days of age (ALGA0092396, P = 5.35 × 10(-9) , Bonferroni adjusted P < 0.05). The SNP marker was located near the genomic region containing IRX4, which encodes iroquois homeobox 4. This SNP marker could be useful in the selective breeding program after validating its effect on other populations.

Genome-wide association study identifies quantitative trait loci affecting hematological traits in an F2 intercross between Landrace and Korean native pigs.

Changes affecting the status of health and robustness can bring about physiological alterations including hematological parameters in swine. To identify quantitative trait loci (QTL) associated with eight hematological traits (one leukocyte trait, six erythrocyte traits and one platelet trait), we conducted a genome-wide association study using the PorcineSNP60K BeadChip in a resource population derived from an intercross between Landrace and Korean native pigs. A total of 36 740 SNPs from 816 F2 progeny were analyzed for each blood-related trait after filtering for quality control. Data were analyzed by the genome-wide rapid association using mixed model and regression (GRAMMAR) approach. A total of 257 significant SNPs (P < 1.36 × 10(-6) ) on SSC3, 6, 8, 13 and 17 were identified for blood-related traits in this study. Interestingly, the genomic region between 17.9 and 130 Mb on SSC8 was found to be significantly associated with red blood cell, mean corpuscular volume and mean corpuscular hemoglobin. Our results include the identification of five significant SNPs within five candidate genes (KIT, IL15, TXK, ARAP2 and ERG) for hematopoiesis. Further validation of these identified SNPs could give valuable information for understanding the variation of hematological traits in pigs.

QTL analysis of body weight and carcass body length traits in an F2 intercross between Landrace and Korean native pigs.

Growth traits, such as body weight and carcass body length, directly affect productivity and economic efficiency in the livestock industry. We performed a genome-wide linkage analysis to detect the quantitative trait loci (QTL) that affect body weight, growth curve parameters and carcass body length in an F2 intercross between Landrace and Korean native pigs. Eight phenotypes related to growth were measured in approximately 1000 F2 progeny. All experimental animals were subjected to genotypic analysis using 173 microsatellite markers located throughout the pig genome. The least squares regression approach was used to conduct the QTL analysis. For body weight traits, we mapped 16 genome-wide significant QTL on SSC1, 3, 5, 6, 8, 9 and 12 as well as 22 suggestive QTL on SSC2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 16 and 17. On SSC12, we identified a major QTL affecting body weight at 140 days of age that accounted for 4.3% of the phenotypic variance, which was the highest test statistic (F-ratio = 45.6 under the additive model, nominal P = 2.4 × 10(-11) ) observed in this study. We also showed that there were significant QTL on SSC2, 5, 7, 8, 9 and 12 affecting carcass body length and growth curve parameters. Interestingly, the QTL on SSC2, 3, 5, 6, 8, 9, 10, 12 and 17 influencing the growth-related traits showed an obvious trend for co-localization. In conclusion, the identified QTL may play an important role in investigating the genetic structure underlying the phenotypic variation of growth in pigs.

The use of collagen content as determined by spectral domain polarization-sensitive optical coherence tomography to assess colon anastomosis healing in a rat model.

BACKGROUND/PURPOSE: Many studies have been undertaken to prevent anastomosis leakage of the colon, and several methods have been used to assess anastomosis healing, such as measurement of bursting pressure or hydroxyproline (a marker of collagen) content at the anastomosis site. However, these methods are inappropriate for comparing anastomosis healing at two time points in the same animals. In the present study, we measured the collagen level by spectral domain polarization-sensitive optical coherence tomography (SD-PS-OCT) to assess anastomosis healing. METHODS: Sprague-Dawley rats were divided into groups C (saline-administered controls; study group) and M [a 5-fluorouracil (5-FU)-administered experimental group]. Immediately after end-to-end anastomosis of the colon, SD-PS-OCT images of anastomoses were taken (baseline). Animals were administered saline or 5-FU for 7 days. On the 7th postoperative day, SD-PS-OCT images were acquired, a histopathologic exam was performed, and hydroxyproline levels as well as mRNA expressions of collagen-1 and collagen-3 were measured at the anastomosis site. RESULTS: Fibroblast proliferation and inflammatory cell infiltration were greater in group C than in group M. The mRNA expressions of collagen-1 and collagen-3 were substantially higher in group C. Hydroxyproline levels were higher in group M than in group C. Though collagen levels measured by SD-PS-OCT at 7 days were elevated compared with baseline in group C, no such changes were observed for group M. CONCLUSION: Collagen levels at the colon anastomosis site, measured with SD-PS-OCT, were not increased at 7 days postoperatively versus baseline when 5-FU was injected, but were increased in saline-treated controls. The measurement of collagen content by SD-PS-OCT was found to provide a good means of assessing anastomosis healing, because it allows in situ assessment of collagen contents at baseline and during the postoperative period.

The Possibility of TBC1D21 as a Candidate Gene for Teat Numbers in Pigs.

Based on a quantitative traits locus (QTL) study using a F2 intercross between Landrace and Korean native pigs, a significant QTL affecting teat numbers in SSC7 was identified. The strong positional candidate gene, TBC1D21, was selected due to its biological function for epithelial mesenchymal cell development. Sequence analysis revealed six single nucleotide polymorphisms (SNPs) in the TBC1D21 gene. Among these, two SNP markers, one silent mutation (SNP01) for g.13,050A>G and one missense mutation (SNP04) for c.829A>T (S277C), were genotyped and they showed significant associations with teat number traits (p value = 6.38E-05 for SNP01 and p value = 1.06E-07 for SNP04 with total teat numbers). Further functional validation of these SNPs could give valuable information for understanding the teat number variation in pigs.

In Vitro Analysis of the Efficacy of Endovascular Thrombectomy Techniques according to the Vascular Tortuosity Using 3D Printed Models.

BACKGROUND AND PURPOSE: Achieving complete recanalization with the front-line endovascular thrombectomy device improves the outcome of acute stroke. The aim of this study was to evaluate whether various thrombectomy techniques including contact aspiration, stent retriever thrombectomy, and combination therapy differ in first-pass effect and distal emboli in acute large-vessel occlusion simulated using 3D printed nontortuous and tortuous cerebrovascular anatomy models. MATERIALS AND METHODS: 3D printed flow models were manufactured using angiographic data of nontortuous and acutely angulated tortuous vascular anatomy from real patients. Three thrombectomy techniques, contact aspiration, stent retriever, and combined methods, were tested under proximal protection with the balloon-guiding catheter. The first-pass effect and distal emboli rates were analyzed in addition to the thrombectomy-failure mechanisms of the respective techniques. RESULTS: A total of 30 thrombectomy experiments were performed. The overall incidence of first-pass effect in the nontortuous and tortuous anatomy was 80.0% versus 46.7%. The overall incidence of distal emboli in the nontortuous and tortuous anatomy was 26.7% versus 46.7%. The contact aspiration technique showed better first-pass effect (80.0%) and distal emboli rates (20%) in the tortuous model compared with other techniques. The combined technique did not show remarkable superiority of the first-pass effect and distal emboli in either the nontortuous or tortuous anatomy. Shearing off of the thrombus was the main mechanism of thrombectomy failure in the combined group. CONCLUSIONS: The tortuous vascular anatomy may worsen the first-pass effect and distal emboli rates. The combined techniques failed to show improvement in outcome due to the shearing-off phenomenon of the thrombus during retrieval.

Clot Meniscus Sign: An Angiographic Clue for Choosing between Stent Retriever and Contact Aspiration in Acute Basilar Artery Occlusion.

BACKGROUND AND PURPOSE: The efficacy of mechanical thrombectomy methods may differ depending on the characteristics of the occlusion. The purpose of this study was to compare the recanalization efficacy and treatment outcome of a stent retriever versus contact aspiration in patients with acute basilar artery occlusion according to the angiographic characteristics of the occlusion. MATERIALS AND METHODS: One hundred sixty-one patients with acute basilar artery occlusion who underwent mechanical thrombectomy were retrospectively analyzed. A stent retriever was compared with contact aspiration thrombectomy according to the clot meniscus sign, defined as a meniscoid/tram-track-like sidewall contrast opacification of the thrombus. A propensity score matching analysis was performed. Clinical/angiographic characteristics and treatment and clinical outcomes were compared. RESULTS: Overall, a stent retriever (n = 118) and contact aspiration (n = 43) did not show significant differences in the successful recanalization (82.2% versus 86.0%) and good clinical outcome rates (32.2% versus 39.5%). In patients with the positive meniscus sign, contact aspiration was associated with shorter procedural time (44 versus 26 minutes, P = .018), a lower number of passes (2 versus 1, P = .041), a higher complete recanalization rate (58.8% versus 85.7%, P = .021), and a higher rate of first-pass effect (27.9% versus 53.6%, P = .031) compared with a stent retriever. After propensity score matching, contact aspiration was associated with higher complete recanalization rates (59.3% versus 85.7%, P = .033). No significant differences in the outcomes were noted between a stent retriever and contact aspiration in patients negative for the meniscus sign. CONCLUSIONS: The efficacy of the mechanical thrombectomy techniques may differ according to the angiographic characteristics of occlusion in patients with basilar artery occlusion. Contact aspiration may be more effective in terms of recanalization compared with a stent retriever in patients with the clot meniscus sign.

Efficacy and Safety of Flow-Diverter Therapy for Recurrent Aneurysms after Stent-Assisted Coiling.

BACKGROUND AND PURPOSE: Flow-diverter treatment for previously stented aneurysms has been reported to be less effective and prone to complications. In this study, we evaluated the effectiveness and safety of flow diverters for recurrent aneurysms after stent-assisted coiling. MATERIALS AND METHODS: Patients who underwent flow-diverter placement for recurrent aneurysms after stent-assisted coiling between March 2015 and March 2019 were recruited. Clinical and radiographic characteristics and clinical and angiographic outcomes were retrospectively evaluated. RESULTS: Among 133 patients who underwent flow-diverter insertion, 17 (male/female ratio = 5:12; mean age, 53.8 years) were treated for recurrent aneurysms after stent placement with (n = 16) or without (n = 1) coiling. Eight patients initially presented with subarachnoid hemorrhage; 7, with headache; and 2, with visual field defects. Angiographic morphology included large/giant saccular in 12 patients, dissecting in 2, fusiform in 1, traumatic pseudoaneurysm in 1, and ruptured blood blister-like aneurysm in 1. The duration between the first treatment and flow-diverter placement ranged from 2 weeks to 15 months (median, 6 months). Flow-diverter placement was successful in all cases without any complications. All patients had favorable outcomes (mRS, 0-2), without any newly appearing symptoms. Aneurysms were followed up with conventional angiography at least once in 6-18 months. Sixteen aneurysms showed complete occlusion, and 1 aneurysm was enlarged. CONCLUSIONS: Results from this case series investigating flow-diverter placement for recurrent aneurysms after stent-assisted coiling suggested that the procedure is safe and effective. Further study in a larger population may be warranted.

Incidence of rhegmatogenous retinal detachment after bag-in-the-lens IOL implantation: extended follow-up in a larger cohort of patients.

PURPOSE: To report the incidence of rhegmatogenous retinal detachment (RRD) and associated risk factors after cataract surgery using the bag-in-the-lens (BIL) intraocular lens (IOL) implantation technique. SETTING: Department of Ophthalmology, Antwerp University Hospital, Belgium. DESIGN: Prospective cohort study. METHODS: All consecutive BIL IOL surgeries performed between January 2001 and December 2010 were included, with the exclusion of combined procedures and IOL exchanges. The incidence of RRD was reported first in the total cohort, then in a subgroup of patients with 1 year to 5 years of follow-up, and finally in the group remaining after exclusion of all risk factors, except gender. Risk factors associated with RRD were examined using multiple Cox regression analysis with a random intercept. RESULTS: Rhegmatogenous RD was diagnosed in 36 eyes (1.06%) of 3385 BIL cases, with a mean follow-up of 48.28 ± 40.05 months (range 0 to 195 months). The 2-year cumulative RRD incidence rate was 0.66% (17 cases in 1024 eyes; 0.00% in patients without risk factors). The 5-year cumulative RRD incidence rate was 1.17% (26 cases in 931 eyes; 0.15% without risk factors). Five risk factors were confirmed: male sex, age less than 60 years at the time of surgery, axial length 25.0 mm or greater, a history of contralateral RD, and intraoperative surgical complications. CONCLUSIONS: The incidence of RRD after BIL IOL implantation is comparable with that of lens-in-the-bag (LIB) implantation. This larger study provided a longer follow-up and suggested that RRD incidence is even lower than that previously reported. This study also confirmed intraoperative surgical complications as an additional risk factor for RRD development, as already described with LIB implantation.

Expression of the atf1+ gene is upregulated in fission yeast under nitrosative and nutritional stresses.

This work was designed to assess regulation of the atf1+ gene in the fission yeast Schizosaccharomyces pombe under nitrosative and nutritional stresses, using the atf1+-lacZ fusion gene and RT-PCR. Nitric oxide (NO)-generating sodium nitroprusside (SNP; 10 micromol/L) and nitrogen depletion significantly enhanced synthesis of beta-galactosidase from the atf1+-lacZ fusion gene in S. pombe Pap1-positive KP1 cells, but not in S. pombe Pap1-negative TP108-3C cells. SNP (10 micromol/L) and nitrogen depletion also caused a significant increase in atf1+ mRNA levels in Pap1-positive cells, but not in Pap1-negative cells. Depletion of glucose marginally increased synthesis of beta-galactosidase from the fusion gene in S. pombe Pap1-positive cells. Taken together, the S. pombe atf1+ gene is upregulated by nitrosative and nutritional stresses on a transcriptional level, possibly via the mediation of Pap1.

Stress distribution of three NiTi rotary files under bending and torsional conditions using a mathematic analysis.

AIM: To compare and evaluate the stress distribution of three NiTi instruments of various cross-sectional configurations under bending or torsional condition using a finite-element analysis model. METHODOLOGY: Three NiTi files (ProFile, ProTaper and ProTaper Universal) were scanned using Micro-CT to produce a three-dimensional digital model. The behaviour of the instrument under bending or torsional loads was analysed mathematically in software (ABAQUS V6.5-1), taking into consideration the nonlinear mechanical characteristic of NiTi material. RESULTS: ProFile showed the greatest flexibility, followed by ProTaper Universal and ProTaper. The highest stress was observed at the surface near the cutting edge and the base of (opposing) flutes during cantilever bending. Concentration of stresses was observed at the bottom of the flutes in ProFile and ProTaper Universal instruments in torsion. The stress was more evenly distributed over the surface of ProTaper initially, which then concentrated at the middle of the convex sides when the amount of angular deflection was increased. CONCLUSION: Incorporating a U-shaped groove in the middle of each side of the convex-triangular design lowers the flexural rigidity of the origin ProTaper design. Bending leads to the highest surface stress at or near the cutting edge of the instrument. Stress concentration occurs at the bottom of the flute when the instrument is subjected to torsion.

Mechanical response of nickel-titanium instruments with different cross-sectional designs during shaping of simulated curved canals.

AIM: To evaluate how different cross-sectional designs affect stress distribution in nickel-titanium (NiTi) instruments during bending, torsion and simulated shaping of a curved canal. METHODOLOGY: Four NiTi rotary instruments with different cross-sectional geometries were selected: ProFile and HeroShaper systems with a common triangle-based cross section, Mtwo with an S-shaped rectangle-based design and NRT with a modified rectangle-based design. The geometries of the selected files were scanned in a micro-CT and three-dimensional finite-element models were created for each system. Stiffness characteristics for each file system were determined in a series of bending and torsional conditions. Canal shaping was simulated by inserting models of the rotating file into a 45 degrees curved canal model. Stress distribution in the instruments was recorded during simulated shaping. After the instruments were retracted from the canal, residual stresses and permanent bending of their tips due to plastic deformation were determined. RESULTS: The greatest bending and torsional stiffness occurred in the NRT file. During simulated shaping, the instruments with triangle-based cross-sectional geometry had more even stress distributions along their length and had lower stress concentrations than the instruments with rectangle-based cross sections. Higher residual stresses and plastic deformations were found in the Mtwo and NRT with rectangle-based cross-sectional geometries. CONCLUSIONS: Nickel-titanium instruments with rectangle-based cross-sectional designs created higher stress differentials during simulated canal shaping and may encounter higher residual stress and plastic deformation than instruments with triangle-based cross sections.

Impact of Balloon-Guiding Catheter Location on Recanalization in Patients with Acute Stroke Treated by Mechanical Thrombectomy.

BACKGROUND AND PURPOSE: Mechanical thrombectomy with proximal flow control and forced aspiration may improve the outcome of endovascular revascularization therapy for patients with acute stroke. The purpose of this study was to compare the impact of balloon-guiding catheter locations in patients treated for anterior circulation acute ischemic stroke using mechanical thrombectomy. MATERIALS AND METHODS: The influence of the balloon-guiding catheter location (proximal, balloon-guiding catheter tip proximal to C1 vertebral body; distal, between the skull base and the C1 vertebral body) was analyzed in patients with acute anterior circulation stroke treated with stent-retriever thrombectomy. The baseline angiographic/clinical characteristics, time intervals, recanalization rates, and clinical outcomes were compared. RESULTS: The clinical analysis included 102 patients (mean age, 69.5 ± 12.8 years; male/female ratio = 52:50). The balloon-guiding catheter was located distally in 49 patients and proximally in 53 patients for flow control and forced aspiration during stent retrieval. The puncture-to-recanalization time was shorter in the distal group than in the proximal group (40 versus 56 minutes, P = .02). Successful and complete recanalizations were more frequently achieved in the distal group compared with the proximal group (98.0% versus 75.5%. P = .003; 67.3% versus 45.3%, P = .04, respectively). Multivariate analysis showed that the distal catheterization location was independently associated with successful recanalization (adjusted OR, 13.4; 95% CI, 2.4-254.8; P = .02). CONCLUSIONS: Location of the balloon-guiding catheter has a significant impact on recanalization in patients with acute stroke. The balloon-guiding catheter should be positioned as distally as safely possible in the cervical ICA for maximally effective thrombectomy.

Maximum expiratory flow rates in induced bronchoconstriction in man.

We evaluated changes of maximum expiratory flow-volume (MEFV) curves and of partial expiratory flow-volume (PEFV) curves caused by bronchoconstrictor drugs and dust, and compared these to the reverse changes induced by a bronchodilator drug in previously bronchoconstricted subjects. Measurements of maximum flow at constant lung inflation (i.e. liters thoracic gas volume) showed larger changes, both after constriction and after dilation, than measurements of peak expiratory flow rate, 1 sec forced expiratory volume and the slope of the effort-independent portion of MEFV curves. Changes of flow rates on PEFV curves (made after inspiration to mid-vital capacity) were usually larger than those of flow rates on MEFV curves (made after inspiration to total lung capacity). The decreased maximum flow rates after constrictor agents are not caused by changes in lung static recoil force and are attributed to narrowing of small airways, i.e., airways which are uncompressed during forced expirations. Changes of maximum expiratory flow rates at constant lung inflation (e.g. 60% of the control total lung capacity) provide an objective and sensitive measurement of changes in airway caliber which remains valid if total lung capacity is altered during treatment.