Cascaded multicore fiber interferometers for enhanced bending sensing based on the Vernier effect.

In this paper, cascaded modal interferometers constructed by strongly-coupled seven-core fiber (SC-SCF) with different lengths are demonstrated for enhanced bending sensing based on Vernier effect. The free spectral range (FSR) of a single SC-SCF interferometer is determined by the length of SC-SCF. Two SC-SCF interferometers with different FSRs are cascaded, in which, one functions as the sensor while the other functions as the reference. The wavelength shift of the envelope of the output spectrum is much larger than that of a single SC-SCF interferometer due to the Vernier effect. Therefore, enhanced sensing can be achieved. Experimental results show that the bending sensitivity of the proposed sensor is improved from -2.20 nm/m-1 (single SC-SCF interferometer) to 42.32 nm/m-1 (cascaded SC-SCF interferometers). The temperature response of the sensor is also investigated. Our proposed cascaded SC-SCF sensor has advantages of high sensitivity, ease of fabrication, and low cost. It is attractive for high precision bending sensing applications.

Investigating Oxidative Stress Associated with Myocardial Fibrosis by High-Fidelity Visualization and Accurate Evaluation of Mitochondrial GSH Levels.

Myocardial fibrosis is frequently accompanied by elevated levels of oxidative stress. Mitochondrial glutathione (mGSH), an essential biomolecule for maintaining redox homeostasis in mitochondria, could serve as an effective indicator for investigating the oxidative stress associated with myocardial fibrosis. In this study, a ratiometric fluorescent probe named Mito-NS6, capable of being anchored in mitochondria and reversibly responding to GSH with an appropriate dissociation equilibrium constant, was rationally designed and utilized to visualize and evaluate the changes of mGSH levels caused by oxidative stress in myocardial fibrosis. Benefiting from the good performance of Mito-NS6, we successfully achieved the quantification of mGSH in cardiac fibroblasts using a confocal laser-scanning microscope, revealing that salvianolic acid B (SalB) can act as an effective drug to alleviate myocardial fibrosis through depressing oxidative stress. Moreover, we employed ratio fluorescence imaging to track the fluctuation in GSH levels within a mice model of myocardial fibrosis induced by isoproterenol and found that myocardial fibrosis caused a higher oxidative stress level in myocardial tissue as well as heart organs. These results provide a novel point of view for the diagnosis and treatment of myocardial fibrosis.

Accurate Detection of Hcy in Human Serum and Two-Photon Visualization of Atherosclerosis Using a Highly Specific Fluorescent Probe.

As an important metabolic intermediate of sulfur-containing amino acids in human body, homocysteine (Hcy) is regarded as an independent risk factor for atherosclerotic cardiovascular disease. Therefore, real-time monitoring of the fluctuation of Hcy level is of great importance for the early diagnosis as well as the treatment of atherosclerosis. Herein, a new two-photon (TP) fluorescent probe (RH-2) was developed via a hydrogen bond-assisted strategy, which had a high specificity for detecting Hcy over cysteine (Cys) and glutathione (GSH) in solution, cells, and tissue. Probe RH-2 was applied to the quantitative determination of Hcy in human serum successfully. Moreover, the two-photon fluorescence (TPF) imaging of abnormal expression of Hcy in aortic vessels and liver of atherosclerotic model mice were fulfilled by RH-2. Therefore, probe RH-2 can be served as a potential tool to understand the function of Hcy in atherosclerosis, supplying a clinical promise for the early diagnosis of atherosclerosis (AS).

A dual-salt fluorescent probe for specific recognition of mitochondrial NADH and potential cancer diagnosis.

Reduced nicotinamide adenine dinucleotide (NADH) is a kind of coenzyme and widely works as a biomarker in cancer cells. It plays a crucial role in many cellular metabolic processes, especially NADH in mitochondria is indispensable for the mitochondrial respiration chain that produces ATP. Herein, we designed a fluorescent probe Mito-FCC based on an ethylene-bridging dual-salt structure, in which benzo[e]indolium fluorophore was used as the mitochondria-targeting group and 1-methylquinolinium moiety as the NADH recognition unit. Mito-FCC exhibited high sensitivity and selectivity for NADH with a rapid "turn-on" fluorescence signal. The dual-salt structure endowed the probe with a reliable mitochondria-targeted ability even after the recognition unit was reduced by NADH. With the help of the probe, the fluctuations of endogenous NADH induced by glucose or pyruvate were imaged. Besides, Mito-FCC had a capability to make a distinction between cancer cells and normal cells due that the content of NADH in cancer cells was distinctly higher than that in normal ones. Notably, the visualization of tumor in vivo through monitoring NADH using Mito-FCC was realized successfully. These experimental results showed that Mito-FCC hold a great perspective in study of mitochondrial function and potential diagnosis of cancer diseases.

Supermode Bragg grating inscribed in a strongly coupled seven-core fiber and its responses to temperature and curvature.

A Bragg grating is successfully inscribed in a piece of strongly coupled seven-core fiber (SCF). There are two separate Bragg resonance notches observed in the transmission spectrum, corresponding to backward coupling of HE11-like and HE12-like supermodes of the SCF. The mode coupling mechanism of the Bragg grating is theoretically investigated via modeling and analyzing modal properties of the SCF. The theoretical results agree well with the experimental results. Since the SCF is spliced between two standard single mode fibers with central alignments at both ends, the transmission spectrum of the device also contains a set of interference fringe due to modal interference between the supermodes. The device's responses to temperature and curvature are experimentally measured, respectively. The obtained temperature sensitivities and curvature sensitivities of the supermode Bragg grating notches are 9.55 pm/°C and 9.55 pm/°C, -1.8 pm/m-1 and -112.3 pm/m-1, respectively. The obtained temperature sensitivity and curvature sensitivity of one of the interference spectrum dips are 11.8 pm/°C and -3909.8 pm/m-1, respectively. This device is potentially useful for simultaneous measurement of temperature and curvature.

An Oligopeptide-Protected Ultrasmall Gold Nanocluster with Peroxidase-Mimicking and Cellular-Imaging Capacities.

Recent decades have witnessed the rapid progress of nanozymes and their high promising applications in catalysis and bioclinics. However, the comprehensive synthetic procedures and harsh synthetic conditions represent significant challenges for nanozymes. In this study, monodisperse, ultrasmall gold clusters with peroxidase-like activity were prepared via a simple and robust one-pot method. The reaction of clusters with H2O2 and 3,3',5,5'-tetramethylbenzidine (TMB) followed the Michaelis-Menton kinetics. In addition, in vitro experiments showed that the prepared clusters had good biocompatibility and cell imaging ability, indicating their future potential as multi-functional materials.

Splenic Artery Pseudoaneurysm in Chronic Pancreatitis Causing Obstructive Jaundice: Endovascular Management.

BACKGROUND: Splenic artery pseudoaneurysm (SAP) around the pancreatic head causing obstructive jaundice is an extremely rare complication but can be life threatening once occurs. This case report is to raise awareness of this catastrophic complication and share our experience of successful endovascular management. METHODS: A 47-year-old male with a history of chronic pancreatitis clinically presented with epigastric pain and jaundice. Proximal SAP complicated with obstructive jaundice was confirmed by laboratory and imaging investigations. The SAP was successfully treated by transarterial coil embolization, and the jaundice subsequently improved. RESULTS: Abdominal contrast-enhanced computed tomography 11 months after embolization showed complete occlusion and reduction in the volume of the SAP as well as normal biliary tract. CONCLUSIONS: SAP complicated with obstructive jaundice should be managed timeously and aggressively once diagnosed, given its potential adverse consequences. Transarterial embolization using the isolation technique may be a safe and effective strategy for treating this disease.

Morphologic Features of Symptomatic and Ruptured Abdominal Aortic Aneurysm in Asian Patients.

BACKGROUND: To evaluate morphologic features of symptomatic and ruptured abdominal aortic aneurysms in Asian patients. METHODS: Two hundred sixty four continuous candidates with an abdominal aortic aneurysm (AAA) were retrospectively identified from a tertiary hospital database between January 2017 and May 2019. The patients meeting inclusion criteria were divided into symptomatic or ruptured AAA (srAAA) and asymptomatic AAA (asAAA) groups. Their computed tomography angiographies were reconstructed using centerline technique and the geometric features of AAAs between the 2 groups were compared. RESULTS: One hundred two patients fulfilled selection criteria (mean age 71 years, 80 men), comprising 35 srAAAs and 67 asAAAs. There was no essential association between gender, smoking or hypertension, and AAA-associated symptoms or rupture. The maximum diameter (5.8 ± 1.4 cm vs. 5.0 ± 0.9 cm; P = 0.001), length (8.8 ± 0.6 cm vs. 7.0 ± 0.3 cm; P = 0.002), and intraluminal thrombus (ILT) thickness (1.7 ± 0.2 cm vs. 1.3 ± 0.1 cm; P = 0.039) of AAAs were independent risk factors for AAA-associated symptoms or rupture (binary logistic regression, P < 0.05), but AAA length and ILT were strongly correlated with the AAA diameter (Pearson correlation coefficient value of 0.591 and 0.444) whereas other factors such as aneurysmal tortuosity, aneurysmal neck anatomy, or common iliac artery geometry were nonsignificant. CONCLUSIONS: AAA diameter, length, and intraluminal thrombus thickness were identified as risk factors for AAA-associated symptoms in Asian patients. While the diameter is regarded as the most important predictor for symptoms and rupture, AAA length and ILT thickness should also be taken into consideration when contemplating intervention, particularly for borderline and smaller aneurysms.

Endovascular Management of Isolated Superior Mesenteric Artery Dissecting Aneurysm by Retrograde Catheterization Via Collaterals from the Celiac Artery.

Isolated superior mesenteric artery (SMA) dissecting aneurysm is frequently symptomatic and potentially catastrophic; thus, it usually requires endovascular treatment. The endovascular management can be challenging in certain cases as catheterization of the collapsed true lumen is often very difficult. This case report is to describe a new approach for catheterization of the true lumen of the SMA in a case of isolated SMA dissecting aneurysm. A 63-year-old male with an SMA dissecting aneurysm underwent stent-graft placement for treatment. Catheterization of the true lumen via the anterograde approach was unsuccessful because of angulation and collapse of the SMA true lumen as a result of the dissecting aneurysm. A guidewire was passed through the collaterals from the celiac artery and retrogradely passed across the collapsed SMA true lumen into the aorta. We then used a snare that had been delivered through the contralateral femoral access to capture and retrieve the guidewire. A delivery system was advanced into the SMA, and a stent graft was successfully deployed to occlude the dissecting aneurysm. This report introduces a new feasible retrograde approach that provides access to the SMA true lumen via celiac collaterals in cases of difficult antegrade catheterization of an SMA dissecting aneurysm.

A modified endovascular technique for treating spontaneous isolated superior mesenteric artery dissection and the early to medium-term outcomes.

PURPOSE: The spontaneous isolated dissection of superior mesenteric artery (SIDSMA) is a rare medical condition and the treatment remains controversial. This study is to present our refined technique with a Flexor introducer to facilitate stent advancement and its early to medium-term outcomes. METHODS: A total of 16 patients diagnosed with SIDSMA and repaired with endovascular stenting from January 2012 to December 2017 were retrospectively identified. All patients were male, and the average age was 56 years old (range from 48 to 72 years old). Diagnosis was preoperatively confirmed using computed tomography angiography and their morphologic features were measured. A long Flexor introducer was delivered to the true lumen of dissected superior mesenteric artery prior to coaxially advancing a stent. Patient demographics, endovascular procedures and postoperative outcomes were collected for analysis. RESULTS: Total technical success was 87.5%. Endovascular attempt was unsuccessful in two patients with extensive thrombus, and the guidewire failed to pass through the true lumen. The remaining 14 SMA dissections were successfully repaired with the modified method. Four patients were repaired using bare stents and 10 with covered stents. The average operative duration was 44 ± 18 minutes. Abdominal pain was relieved postoperatively in all cases except one patient with no identified reasons. The median follow-up duration was 17 months (2-63 months). No procedure- or dissection-related symptoms was present during follow up, and postoperative computed tomography angiography showed all stented SMAs were patent. CONCLUSIONS: Coaxial delivery of stents within the introducer can yield high technical success and good clinical outcomes in early to medium term. Extensive thrombus inside SIDSMA is the exclusive cause for endovascular failure with this technique.

Geometric Alteration of Renal Arteries After Fenestrated Grafting and the Impact on Renal Function.

BACKGROUND: This study aims to investigate the degree of geometric change on renal arteries and its impact on renal function after fenestrated endovascular aortic repair (fEVAR). METHODS: Twenty-five patients with fEVAR were included. There were 47 renal arteries target vessels, and 43 of these (22 left and 21 right vessels) stented successfully. Their preoperative and first postoperative follow-up computed tomography (CT) images were reconstructed using the Aquarius workstation (TeraRecon, San Mateo, CA, USA). The superior mesenteric artery (SMA) or celiac axis (if SMA was stented) was appointed as reference origin. The longitudinal orientation of a renal artery or a stent was represented by a takeoff angle (ToA) between the renal artery or stent and the distal abdominal aorta. The postoperative stent ToAs were compared with those of preoperative renal arteries. Preoperative and short-term postoperative serum creatinine levels were measured. Renal function impairment was indicated as a >30% or >2.0 mg/dL rise in serum creatinine compared to the preoperative level. The relationship between postoperative renal function impairment and the stent orientation or geometric changes in renal arteries was correlated. RESULTS: The patency rate of renal arteries was 100% at the first postoperative CT review. The average ToAs of both renal arteries were significantly enlarged after stenting (P < 0.05). Seven stent deformations (16.3%) in four patients (16.0%) were observed. They were attributed to caudal misalignment of the fenestrated stent graft (n = 6) or inaccurate graft sizing (n = 1). There was no stent fracture or target vessel loss. Postoperatively, nine patients (36.0%) at day 1 and 10 patients (41.7%) after 3 months suffered the renal function impairment. This was found not to be associated with the stent angulation or angular change of the renal arteries (both P > 0.05). The three patients with stent deformation due to misalignment suffered postoperative renal function impairment and continuing deterioration in renal function. CONCLUSIONS: Implanted renal stents could angulate renal arteries more cephalad after fenestrated stenting. Postoperative renal function impairment was not associated with the stent orientation and changes in vessel orientation. Accurate fenestrated alignment is important to maintain stent performance and preserve renal function.

A Systematic Review of Fenestrated Endovascular Repair for Juxtarenal and Short-Neck Aortic Aneurysm: Evidence So Far.

BACKGROUND: Fenestrated endovascular repair is an alternative to open repair in the management of juxtarenal aortic aneurysms and short-neck abdominal aortic aneurysms (AAAs). The aim of this article is to examine the evidence in published literature on the use of fenestrated endovascular stent grafts in the treatment of juxtarenal and short-neck AAAs. METHODS: Systematic review was formulated under the instruction of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Articles published from January 1996 to October 2014 in English language were included. Published studies on fenestrated endovascular stent grafts in treating juxtarenal and short-neck AAAs were systematically searched and reviewed through a computerized search of PubMed and Ovid MEDLINE and cross-referenced. Title key words include "fenestrated", "juxtarenal", and "short neck". All relevant published articles up to first October 2014 were reviewed. RESULTS: A total of 529 nonduplicated publications were identified but only 15 articles were eligible for our qualitative analysis, with 763 patients and 2,040 target vessels. Twelve studies were included in cohort studies with a short or medium follow-up period (median range, 6-67 months). The mean 30-day and late follow-up mortality were 1.7% (range, 0-4%) and 20.1% (range, 4-50%), respectively, with 5.3% aneurysm-related late deaths. A total of 74 target vessels (3.6%) were lost in all the studies with 65 of them (87.8%) lost postoperatively. Overall, 28.8% patients endured renal dysfunction postoperatively, whereas 2.5% of patients required dialysis. Target vessel events and endoleaks were the 2 major indications for reintervention, accounting for 63.8%. Fourteen aneurysm sacs (1.8%) were enlarged continuously during follow-up and a half were due to type II endoleaks. Migration of the proximal fenestration component was reported with 3.0%. One registry study reported 4.1% of early mortality, higher than any cohort studies, whereas the target vessel loss was relatively low (1.6%). Freedom of late secondary intervention decreased from 90% at year 1 to 70% at year 3. Two nonrandom controlled comparative studies showed no definitive superiority of fenestrated repair over the open surgery. CONCLUSIONS: Contemporary published literature does not produce a high enough level of evidence that leads to a change in treatment guidelines for juxtarenal or short-neck aneurysm. Fenestrated endovascular repair is a safe and efficacious treatment, particularly for those deemed surgically high risk. Growing experience and innovation of stent graft are essential for the advancement of fenestrated grafting.

The compatibility of p-branch "off-the-shelf" fenestrated endovascular graft in Asian patients with juxtarenal aortic aneurysm.

OBJECTIVE: The Zenith pivot branch (p-branch) fenestrated endovascular graft (Cook Medical, Bloomington, Ind) is a new "off-the-shelf" device to treat patients with juxtarenal aortic aneurysms (JRAs). Two options are currently available, which appear to suit >70% of white patients. This study investigates the anatomic applicability of the p-branch fenestrated graft in a cohort of Asian patients with JRA. METHODS: Computed tomography images of 51 consecutive Asian patients with JRA (43 men; mean age, 76.8 years) were analyzed on an Aquarius workstation (TeraRecon, San Mateo, Calif) and matched to two current configurations of the p-branch (options A and B: single superior mesenteric artery [SMA] and two renal fenestrations, and a celiac axis scallop). With use of the SMA as reference, the anatomic positions of both renal arteries and the celiac axis were figured together with their diameters on a template generated on MATLAB (MathWorks, Natick, Mass), and then they were matched with two graft configurations. The renal artery origins were assessed for three classes of "closeness of fit" based on diameter: perfect match, marginal match, and mismatch, respectively, defined as the renal artery origins being located entirely inside, partially inside, and completely outside their corresponding fenestrations. The suitability of the p-branch graft design to the aneurysms was then evaluated. RESULTS: A total of 31 JRA patients (60.8%) were regarded as suitable candidates for one or both p-branch stent grafts (20 with option A, 22 with option B, and 11 with both options). In 35 patients (68.6%), both renal arteries could be aligned with the fenestrations. Among them, 16 patients (31.4%) were perfectly matched, whereas 19 patients (37.2%) were only marginally suitable. The major reason for exclusion was the misalignment of the renal fenestrations. In 16 patients with unsuitable renal fenestrations, 8 were attributed to the right renal origins being located too distally compared with their corresponding fenestrations. Another reason for exclusion was the position of the celiac axis scallop in four patients (7.84%), and insufficient aortic length for the graft was encountered in another four. If the right renal fenestration of option B was adjusted to 20 mm caudal to the SMA fenestration (level with the left fenestration), the match of renal fenestration could reach 78.4% (40 of 51). CONCLUSIONS: The present design of the p-branch off-the-shelf fenestrated graft is feasible for a good proportion of JRA patients in Asia. Further refinement of design may improve the anatomic match, especially a lower right renal artery origin.