Safety and success of transvenous lead extraction using excimer laser sheaths: a meta-analysis of over 1700 patients.

AIMS: While numerous studies have demonstrated favourable safety and efficacy of the excimer laser sheath for transvenous lead extraction (TLE) in smaller cohorts, comprehensive large-scale investigations with contemporary data remain scarce. This study aims to evaluate the safety and performance of laser-assisted TLE through a meta-analysis of contemporary data. METHODS AND RESULTS: A systematic literature search was conducted to identify articles that assessed the safety and performance of the spectranetics laser sheath (SLS) II and GlideLight Excimer laser sheaths in TLE procedures between 1 April 2016 and 31 March 2021. Safety outcomes included procedure-related death and major/minor complications. Performance outcomes included procedural and clinical success rates. A random-effects, inverse-variance-weighting meta-analysis was performed to obtain the weighted average of the evaluated outcomes. In total, 17 articles were identified and evaluated, including 1729 patients with 2887 leads. Each patient, on average, had 2.3 ± 0.3 leads with a dwell time of 7.9 ± 3.0 years. The TLE procedural successes rate was 96.8% [1440/1505; 95% CI: (94.9-98.2%)] per patient and 96.3% [1447/1501; 95% CI: (94.8-97.4%)] per lead, and the clinical success rate per patient was 98.3% [989/1010, 95% CI: (97.4-99.0%)]. The procedure-related death rate was 0.08% [7/1729, 95% CI: (0.00%, 0.34%)], with major and minor complication rates of 1.9% [41/1729; 95% CI: (1.2-2.8%)] and 1.9% [58/1729; 95% CI: (0.8-3.6%)], respectively. CONCLUSION: This meta-analysis demonstrated that excimer laser sheath-assisted TLE has high success and low procedural mortality rates. It provides clinicians with a reliable and valuable resource for extracting indwelling cardiac leads which require advanced extraction techniques.

Safety and Success Rates of Excimer Laser Sheath-Assisted Retrieval of Embedded Inferior Vena Cava Filters.

Importance: Despite historically high rates of use, most inferior vena cava (IVC) filters are not retrieved. The US Food and Drug Administration safety communications recommended retrieval when the IVC filter is no longer indicated out of concern for filter-related complications. However, failure rates are high when using standard techniques for retrieval of long-dwelling filters, and until recently, there have been no devices approved for retrieval of embedded IVC filters. Objective: To evaluate the safety and success of excimer laser sheath-assisted retrieval of embedded IVC filters. Design, Setting, and Participants: A retrospective, multicenter, clinical cohort study of excimer laser sheath-assisted IVC filter retrievals from 7 US sites was conducted between March 1, 2012, and February 28, 2021, among 265 patients who underwent IVC filter retrieval using the laser. Patients were substratified between a high-volume single center and a multicenter data set. A blinded physician committee adjudicated reported complications and their association with use of the laser. Exposures: Retrieval of IVC filters using excimer laser sheath. Main Outcomes and Measures: The primary safety end point was device-related major complication rate (Society of Interventional Radiology categories C to F, which included any adverse event associated with morbidity or disability that increases the level of care, results in hospital admission, or substantially lengthens the hospital stay). The primary success end point was technical success of IVC filter retrieval. The primary end points were compared with literature-derived, meta-analysis-suggested target performance goals. Results: The single-center experience included 139 participants (mean [SD] age, 52 [16] years; 78 female participants [56.1%]), and the multicenter experience included 126 participants (mean [SD] age, 52 [16] years; 75 female participants [59.5%]). The device-related major complication rate was 2.9% (4 of 139; 95% CI, 0.8%-7.2%; P = .001) for the single-center experience and 4.0% (5 of 126; 95% CI, 1.3%-9.0%; P = .01) for the multicenter experience, both of which were significantly lower than the primary safety performance goal (10%). No major complications were considered to be definitively associated with use of the laser. The technical success rate was 95.7% (133 of 139; 95% CI, 90.8%-98.4%; P = .007) for the single-center experience and 95.2% (120 of 126; 95% CI, 89.9%-98.2%; P = .02) for the multicenter experience, both of which were significantly higher than the primary performance goal (89.4%). Conclusions and Relevance: This cohort study demonstrated high technical success and low complication rates of excimer laser sheath-assisted retrieval of embedded IVC filters in centers with variable case volume and experience, which suggests a wide applicability of the technique with proper training. The excimer laser sheath offers physicians a valuable tool for retrieval of challenging embedded IVC filters.

Connexin 43 mediated the angiogenesis of buyang huanwu decoction via vascular endothelial growth factor and angiopoietin-1 after ischemic stroke.

Buyang Huanwu decoction (BYHWD), a classical prescription for ischemic stroke, has been reported to promote angiogenesis after focal ischemia. However, the mechanisms of the contribution of BYHWD on angiogenesis are still unclear. Connexin 43 (Cx43) played important roles in the functions of neurogliovascular unit. Therefore, the aim of this study was to explore the potential role of Cx43 in angiogenesis of the ischemic brain after BYHWD treatment. Middle cerebral artery occlusion (MCAO) was used to establish the model of focal ischemia. BYHWD was administrated intragastrically twice a day after MCAO with or without Gap26 (a specific Cx43 inhibitor). Western blot, neurological deficits, immunofluorescent staining, and Evans blue dye were used to confirm the role of Cx43 in angiogenesis after BYHWD treatment. The expression levels of total Cx43 and phosphorylated Cx43 were upregulated by BYHWD and peaked at 7 days post MCAO. Inhibition of Cx43 with Gap26 significantly attenuated the protective role of BYHWD in neurological behavior. BYHWD treatment promoted angiogenesis demonstrated by increased microvascular density, upregulated vascular endothelial growth factor (VEGF), and angiopoietin-1 (Ang-1), while inhibition of Cx43 with Gap26 attenuated these effects of BYHWD. In addition, Gap26 inhibited the beneficial effect of BYHWD on blood-brain barrier (BBB) integrity. These results suggested that Cx43 mediated the angiogenesis of BYHWD via VEGF and Ang-1 after focal ischemic stroke.

CXCL10+ peripheral activation niches couple preferred sites of Th1 entry with optimal APC encounter.

Correct positioning of T cells within infected tissues is critical for T cell activation and pathogen control. Upon tissue entry, effector T cells must efficiently locate antigen-presenting cells (APC) for peripheral activation. We reveal that tissue entry and initial peripheral activation of Th1 effector T cells are tightly linked to perivascular positioning of chemokine-expressing APCs. Dermal inflammation induces tissue-wide de novo generation of discrete perivascular CXCL10+ cell clusters, enriched for CD11c+MHC-II+ monocyte-derived dendritic cells. These chemokine clusters are "hotspots" for both Th1 extravasation and activation in the inflamed skin. CXCR3-dependent Th1 localization to the cluster micro-environment prolongs T-APC interactions and boosts function. Both the frequency and range of these clusters are enhanced via a T helper 1 (Th1)-intrinsic, interferon-gamma (IFNγ)-dependent positive-feedback loop. Thus, the perivascular CXCL10+ clusters act as initial peripheral activation niches, optimizing controlled activation broadly throughout the tissue by coupling Th1 tissue entry with enhanced opportunities for Th1-APC encounter.

Longitudinal neural and vascular structural dynamics produced by chronic microelectrode implantation.

Implanted microelectrode arrays sense local neuronal activity, signals which are used as control commands for brain computer interface (BCI) technology. Patients with tetraplegia have used BCI technology to achieve an extraordinary degree of interaction with their local environment. However, current microelectrode arrays for BCIs lose the ability to record high-quality neural signals in the months-to-years following implantation. Very little is known regarding the dynamic response of neurons and vasculature in the months following electrode array implantation, but loss of structural integrity near the electrode may contribute to the degradation of recording signals. Here, we use in-vivo dual-modality imaging to characterize neuronal and vasculature structures in the same animal for 3 months following electrode insertion. We find ongoing neuronal atrophy, but relative vascular stability, in close proximity to the electrode, along with evidence suggesting links between rare, abrupt hypoxic events and neuronal process atrophy.

Longitudinal multimodal assessment of neurodegeneration and vascular remodeling correlated with signal degradation in chronic cortical silicon microelectrodes.

Significance: Cortically implanted microelectrode arrays provide a direct interface with neuronal populations and are used to restore movement capabilities and provide sensory feedback to patients with paralysis or amputation. Penetrating electrodes experience high rates of signal degradation within the first year that limit effectiveness and lead to eventual device failure. Aim: To assess vascular and neuronal changes over time in mice with implanted electrodes and examine the contribution of the brain tissue response to electrode performance. Approach: We used a multimodal approach combining in vivo electrophysiology and subcellular-level optical imaging. Results: At acute timescales, we observed structural damage from the mechanical trauma of electrode insertion, evidenced by severed dendrites in the electrode path and local hypofluorescence. Superficial vessel growth and remodeling occurred within the first few weeks in both electrode-implanted and window-only animals, but the deeper capillary growth evident in window-only animals was suppressed in electrode-implanted animals. After longer implantation periods, there was evidence of degeneration of transected dendrites superficial to the electrode path and localized neuronal cell body loss, along with deep vascular velocity changes near the electrode. Total spike rate (SR) across all animals reached a peak between 3 and 9 months postimplantation, then decreased. The local field potential signal remained relatively constant for up to 6 months, particularly in the high-gamma band, indicating long-term electrode viability and neuronal functioning at further distances from the electrode, but it showed a reduction in some animals at later time points. Most importantly, we found that progressive high-gamma and SR reductions both correlate positively with localized cell loss and decreasing capillary density within 100 µ m of the electrode. Conclusions: This multifaceted approach provided a more comprehensive picture of the ongoing biological response at the brain-electrode interface than can be achieved with postmortem histology alone and established a real-time relationship between electrophysiology and tissue damage.

Robust blind spectral unmixing for fluorescence microscopy using unsupervised learning.

Due to the overlapping emission spectra of fluorophores, fluorescence microscopy images often have bleed-through problems, leading to a false positive detection. This problem is almost unavoidable when the samples are labeled with three or more fluorophores, and the situation is complicated even further when imaged under a multiphoton microscope. Several methods have been developed and commonly used by biologists for fluorescence microscopy spectral unmixing, such as linear unmixing, non-negative matrix factorization, deconvolution, and principal component analysis. However, they either require pre-knowledge of emission spectra or restrict the number of fluorophores to be the same as detection channels, which highly limits the real-world applications of those spectral unmixing methods. In this paper, we developed a robust and flexible spectral unmixing method: Learning Unsupervised Means of Spectra (LUMoS), which uses an unsupervised machine learning clustering method to learn individual fluorophores' spectral signatures from mixed images, and blindly separate channels without restrictions on the number of fluorophores that can be imaged. This method highly expands the hardware capability of two-photon microscopy to simultaneously image more fluorophores than is possible with instrumentation alone. Experimental and simulated results demonstrated the robustness of LUMoS in multi-channel separations of two-photon microscopy images. We also extended the application of this method to background/autofluorescence removal and colocalization analysis. Lastly, we integrated this tool into ImageJ to offer an easy to use spectral unmixing tool for fluorescence imaging. LUMoS allows us to gain a higher spectral resolution and obtain a cleaner image without the need to upgrade the imaging hardware capabilities.

The cytological basis of powdery mildew resistance in wild Chinese Vitis species.

The wild Chinese grapevines (Vitis spp.) show varying levels of resistance to powdery mildew caused by Erysiphe necator that is an economically important disease of cultivated grapevines (Vitis vinifera). However, little information is available regarding the cytological mechanisms of powdery mildew resistance in these wild relatives. Here, we studied the cytological responses of three wild Chinese grapevine accessions after they were infected with E. necator (En) NAFU1 in comparison to the susceptible V. vinifera cv. 'Thompson Seedless' grape. The hyphal growth and sporulation of En NAFU1 were significantly restricted in wild species compared to 'Thompson Seedless', which appears to be associated with early cell wall deposition at the attempt sites, encasement of haustoria, and hypersensitive response-like cell death of penetrated epidermal cells. Moreover, endogenous free salicylic acid (SA) was more abundant in wild Chinese Vitis species than in 'Thompson Seedless' under pathogen-free condition. During En NAFU1 colonization, SA conjugates accumulated higher in wild grapevines than in 'Thompson Seedless'. In addition, the species-specific expression patterns of defense-associated genes during En NAFU1 colonization indicated that mechanisms underlying powdery mildew resistance are divergent among different wild Chinese Vitis species. These results contribute to understanding of mechanisms underlying defense responses of wild Chinese Vitis species against powdery mildew.

Time to wake up: Studying neurovascular coupling and brain-wide circuit function in the un-anesthetized animal.

Functional magnetic resonance imaging (fMRI) has allowed the noninvasive study of task-based and resting-state brain dynamics in humans by inferring neural activity from blood-oxygenation-level dependent (BOLD) signal changes. An accurate interpretation of the hemodynamic changes that underlie fMRI signals depends on the understanding of the quantitative relationship between changes in neural activity and changes in cerebral blood flow, oxygenation and volume. While there has been extensive study of neurovascular coupling in anesthetized animal models, anesthesia causes large disruptions of brain metabolism, neural responsiveness and cardiovascular function. Here, we review work showing that neurovascular coupling and brain circuit function in the awake animal are profoundly different from those in the anesthetized state. We argue that the time is right to study neurovascular coupling and brain circuit function in the awake animal to bridge the physiological mechanisms that underlie animal and human neuroimaging signals, and to interpret them in light of underlying neural mechanisms. Lastly, we discuss recent experimental innovations that have enabled the study of neurovascular coupling and brain-wide circuit function in un-anesthetized and behaving animal models.

Effects of Voluntary Locomotion and Calcitonin Gene-Related Peptide on the Dynamics of Single Dural Vessels in Awake Mice.

The dura mater is a vascularized membrane surrounding the brain and is heavily innervated by sensory nerves. Our knowledge of the dural vasculature has been limited to pathological conditions, such as headaches, but little is known about the dural blood flow regulation during behavior. To better understand the dynamics of dural vessels during behavior, we used two-photon laser scanning microscopy (2PLSM) to measure the diameter changes of single dural and pial vessels in the awake mouse during voluntary locomotion. Surprisingly, we found that voluntary locomotion drove the constriction of dural vessels, and the dynamics of these constrictions could be captured with a linear convolution model. Dural vessel constrictions did not mirror the large increases in intracranial pressure (ICP) during locomotion, indicating that dural vessel constriction was not caused passively by compression. To study how behaviorally driven dynamics of dural vessels might be altered in pathological states, we injected the vasodilator calcitonin gene-related peptide (CGRP), which induces headache in humans. CGRP dilated dural, but not pial, vessels and significantly reduced spontaneous locomotion but did not block locomotion-induced constrictions in dural vessels. Sumatriptan, a drug commonly used to treat headaches, blocked the vascular and behavioral the effects of CGRP. These findings suggest that, in the awake animal, the diameters of dural vessels are regulated dynamically during behavior and during drug-induced pathological states.

Identification and utilization of a new Erysiphe necator isolate NAFU1 to quickly evaluate powdery mildew resistance in wild Chinese grapevine species using detached leaves.

The most economically important disease of cultivated grapevines worldwide is powdery mildew caused by the biotrophic fungal pathogen Erysiphe necator. To integrate effective genetic resistance into cultivated grapevines, numerous disease resistance screens of diverse Vitis germplasm, including wild species, have been conducted to identify powdery mildew resistance, but the results have been inconsistent. Here, a new powdery mildew isolate that is infectious on grapevines, designated Erysiphe necator NAFU1 (En. NAFU1), was identified and characterized by phylogeny inferred from the internal transcribed spacer (ITS) of pathogen ribosomal DNA sequences. Three classical methods were compared for the maintenance of En. NAFU1, and the most convenient method was maintenance on detached leaves and propagation by contact with infected leaves. Furthermore, controlled inoculations of En. NAFU1 were performed using detached leaves from 57 wild Chinese grapevine accessions to quickly evaluate powdery mildew resistance based on trypan blue staining of leaf sections. The results were compared with previous natural epidemics in the field. Among the screened accessions inoculated with En. NAFU1, 22.8% were resistant, 33.3% were moderately resistant, and 43.9% were susceptible. None of the accessions assessed herein were immune from infection. These results support previous findings documenting the presence of race-specific resistance to E. necator in wild Chinese grapevine. The resistance of wild Chinese grapevine to En. NAFU1 could be due to programmed cell death. The present results suggest that En. NAFU1 isolate could be used for future large-scale screens of resistance to powdery mildew in diverse Vitis germplasms and investigations of the interaction between grapevines and pathogens.

Identification, isolation, and expression analysis of heat shock transcription factors in the diploid woodland strawberry Fragaria vesca.

Heat shock transcription factors (Hsfs) are known to play dominant roles in plant responses to heat, as well as other abiotic or biotic stress stimuli. While the strawberry is an economically important fruit plant, little is known about the Hsf family in the strawberry. To explore the functions of strawberry Hsfs in abiotic and biotic stress responses, this study identified 17 Hsf genes (FvHsfs) in a wild diploid woodland strawberry (Fragaria vesca, 2n = 2x = 14) and isolated 14 of these genes. Phylogenetic analysis divided the strawberry FvHsfs genes into three main groups. The evolutionary and structural analyses revealed that the FvHsf family is conserved. The promoter sequences of the FvHsf genes contain upstream regulatory elements corresponding to different stress stimuli. In addition, 14 FvHsf-GFP fusion proteins showed differential subcellular localization in Arabidopsis mesophyll protoplasts. Furthermore, we examined the expression of the 17 FvHsf genes in wild diploid woodland strawberries under various conditions, including abiotic stresses (heat, cold, drought, and salt), biotic stress (powdery mildew infection), and hormone treatments (abscisic acid, ethephon, methyl jasmonate, and salicylic acid). Fifteen of the seventeen FvHsf genes exhibited distinct changes on the transcriptional level during heat treatment. Of these 15 FvHsfs, 8 FvHsfs also exhibited distinct responses to other stimuli on the transcriptional level, indicating versatile roles in the response to abiotic and biotic stresses. Taken together, the present work may provide the basis for further studies to dissect FvHsf function in response to stress stimuli.

Genome-wide Identification and Expression Analysis of the CDPK Gene Family in Grape, Vitis spp.

BACKGROUND: Calcium-dependent protein kinases (CDPKs) play vital roles in plant growth and development, biotic and abiotic stress responses, and hormone signaling. Little is known about the CDPK gene family in grapevine. RESULTS: In this study, we performed a genome-wide analysis of the 12X grape genome (Vitis vinifera) and identified nineteen CDPK genes. Comparison of the structures of grape CDPK genes allowed us to examine their functional conservation and differentiation. Segmentally duplicated grape CDPK genes showed high structural conservation and contributed to gene family expansion. Additional comparisons between grape and Arabidopsis thaliana demonstrated that several grape CDPK genes occured in the corresponding syntenic blocks of Arabidopsis, suggesting that these genes arose before the divergence of grapevine and Arabidopsis. Phylogenetic analysis divided the grape CDPK genes into four groups. Furthermore, we examined the expression of the corresponding nineteen homologous CDPK genes in the Chinese wild grape (Vitis pseudoreticulata) under various conditions, including biotic stress, abiotic stress, and hormone treatments. The expression profiles derived from reverse transcription and quantitative PCR suggested that a large number of VpCDPKs responded to various stimuli on the transcriptional level, indicating their versatile roles in the responses to biotic and abiotic stresses. Moreover, we examined the subcellular localization of VpCDPKs by transiently expressing six VpCDPK-GFP fusion proteins in Arabidopsis mesophyll protoplasts; this revealed high variability consistent with potential functional differences. CONCLUSIONS: Taken as a whole, our data provide significant insights into the evolution and function of grape CDPKs and a framework for future investigation of grape CDPK genes.

Mechanical restriction of intracortical vessel dilation by brain tissue sculpts the hemodynamic response.

Understanding the spatial dynamics of dilation in the cerebral vasculature is essential for deciphering the vascular basis of hemodynamic signals in the brain. We used two-photon microscopy to image neural activity and vascular dynamics in the somatosensory cortex of awake behaving mice during voluntary locomotion. Arterial dilations within the histologically-defined forelimb/hindlimb (FL/HL) representation were larger than arterial dilations in the somatosensory cortex immediately outside the FL/HL representation, demonstrating that the vascular response during natural behaviors was spatially localized. Surprisingly, we found that locomotion drove dilations in surface vessels that were nearly three times the amplitude of intracortical vessel dilations. The smaller dilations of the intracortical arterioles were not due to saturation of dilation. Anatomical imaging revealed that, unlike surface vessels, intracortical vessels were tightly enclosed by brain tissue. A mathematical model showed that mechanical restriction by the brain tissue surrounding intracortical vessels could account for the reduced amplitude of intracortical vessel dilation relative to surface vessels. Thus, under normal conditions, the mechanical properties of the brain may play an important role in sculpting the laminar differences of hemodynamic responses.

Quantitative separation of arterial and venous cerebral blood volume increases during voluntary locomotion.

Voluntary locomotion is accompanied by large increases in cortical activity and localized increases in cerebral blood volume (CBV). We sought to quantitatively determine the spatial and temporal dynamics of voluntary locomotion-evoked cerebral hemodynamic changes. We measured single vessel dilations using two-photon microscopy and cortex-wide changes in CBV-related signal using intrinsic optical signal (IOS) imaging in head-fixed mice freely locomoting on a spherical treadmill. During bouts of locomotion, arteries dilated rapidly, while veins distended slightly and recovered slowly. The dynamics of diameter changes of both vessel types could be captured using a simple linear convolution model. Using these single vessel measurements, we developed a novel analysis approach to separate out spatially and temporally distinct arterial and venous components of the location-specific hemodynamic response functions (HRF) for IOS. The HRF of each pixel of was well fit by a sum of a fast arterial and a slow venous component. The HRFs of pixels in the limb representations of somatosensory cortex had a large arterial contribution, while in the frontal cortex the arterial contribution to the HRF was negligible. The venous contribution was much less localized, and was substantial in the frontal cortex. The spatial pattern and amplitude of these HRFs in response to locomotion in the cortex were robust across imaging sessions. Separating the more localized arterial component from the diffuse venous signals will be useful for dealing with the dynamic signals generated by naturalistic stimuli.

Determination of vessel cross-sectional area by thresholding in Radon space.

The cross-sectional area of a blood vessel determines its resistance, and thus is a regulator of local blood flow. However, the cross-sections of penetrating vessels in the cortex can be non-circular, and dilation and constriction can change the shape of the vessels. We show that observed vessel shape changes can introduce large errors in flux calculations when using a single diameter measurement. Because of these shape changes, typical diameter measurement approaches, such as the full-width at half-maximum (FWHM) that depend on a single diameter axis will generate erroneous results, especially when calculating flux. Here, we present an automated method--thresholding in Radon space (TiRS)--for determining the cross-sectional area of a convex object, such as a penetrating vessel observed with two-photon laser scanning microscopy (2PLSM). The thresholded image is transformed back to image space and contiguous pixels are segmented. The TiRS method is analogous to taking the FWHM across multiple axes and is more robust to noise and shape changes than FWHM and thresholding methods. We demonstrate the superior precision of the TiRS method with in vivo 2PLSM measurements of vessel diameter.