Tunica Adventitia Research Articles

A histological study of vessel wall reaction after endovenous ultrasound ablation in an animal model

Introduction. Along with the generally accepted thermal methods of saphenous varicose veins ablation, the use of non-thermal and combined methods becomes attractive. Due to the variety of mechanisms of action, low-frequency ultrasound is a promising technology for performing a wide range of minimally invasive intravascular operations, including the treatment of varicose veins. Aim. To elucidate the mechanism of action of a novel endovenous ultrasound ablation method and evaluate its effect on vein wall injury and lumen occlusion in an animal model. Materials and methods. A total of 34 central ear vein (CEV) medial ramus were treated in 17 rabbits according to the follow-up protocol. Six femoral veins from three rabbits enrolled into the acute experiment were harvested 45 min after the procedure. All treated CEV medial ramus in the follow-up experiment were divided into four treatment groups with an observation time of: (0) 30 days, control procedure; (1) 60 days, ultrasound ablation; (2) 95 days, ultrasound ablation; (3) 138 days, ultrasound ablation. Results. Occlusion was achieved in all but one CEV medial ramus (29/30; 97%) treated with ultrasound. Histologic examination of treated veins showed heat- and mechanical-induced changes in the vein wall, such as abrasion of the endothelium and fibrotic lesions in the tunica media and tunica adventitia. The occluded segments consisted mainly of cellular fibrotic material. In the acute group, histological evidence of damage to all vessel wall layers was found. Discussion. Ultrasound ablation results in homogeneous and uniform damage to the venous wall. The results of this study suggest that the ultrasound treatment leads to venous occlusion by the additive thermomechanical mechanism of damage to the vessel wall. Conclusions. Endovenous ultrasound ablation showed a similar pattern of thermal damage as endovenous laser (EVLA) and radiofrequency ablation (RFA) and damage to the endothelium as mechanochemical ablation (MOCA). Four months after ultrasound ablation, the occlusion rate was 90%.

On table Ruptured of Brachiocephalic Artery Pseudoaneurysm.

Pseudoaneurysms are abnormal outpouching or dilatation of arteries bound only by the tunica adventitia, the outermost layer of the arterial wall. The presence of a pseudoaneurysm is like a ticking bomb that can rupture anytime causing dire consequences for the patient. The brachiocephalic trunk is an uncommon location for such pseudoaneurysms. We present a patient with this uncommon pseudoaneurysm, which ruptured on the table during stent deployment. We will discuss the diagnosis and management plan for this situation as well as the literature review.

A study on the congruence and proximity of the sling and clasp fibres at the cardio-esophageal junction of the stomach.

The cardio-oesophageal sphincter that is located in close longitudinal proximity to the origin of the lesser curvature of the stomach has a unique pattern of external muscle fibres whose inner oblique layer would normally form an elongated sling and the middle partially circular layer would form a projecting clasp into the already existing muscular sling of the former congruently, which would result in the formation of an anatomical sphincter in that area that would normally be devoid of the external longitudinal muscle layer coat. Certain authors have disagreed with the notion of this standard literature and have proposed that the clasp and sling fibres need not necessarily be congruent and may even remain independent of each other with partial contributions from the longitudinal muscle layers as well that may arise tangentially in different populations, which may in turn contribute to reflux oesophagitis in that population. Hence, the clasp and sling fibre muscular patterns were observed in six formalin-embalmed cadavers at the department of anatomy in a tertiary care institute as part of routine dissections in series, and the findings were then reported. At the junction of the lesser curvature of the stomach with the oesophagus, all six cadavers showed a longitudinal sling pattern as opposed to the conventional oblique sling. The circular muscle layer was found to be merged with the outer longitudinal muscle layer to form the sling that pulled away from the clasp, resulting in a loss of congruency for the same. The clasp fibres, however, were found to be contributed by the inner oblique muscle layer. The conventional perpendicular or tangential merging of the clasp with the sling was not observed; instead, an obtuse, blunt angular merging of the clasp with the sling was observed. The deviation of the sling from the clasp could indicate a lack of a proper fit between them at the cardio-oesophageal sphincter. The lack of robustness in the attachment of the clasp to the sling may possibly contribute to the diminished taut pull of the clasp in this subset of the population. These would be significant determinants for a predisposition to reflux oesophagitis and Barrett's oesophagus.

Adipose-derived stem cells significantly increases collagen level and fiber maturity in patient-specific biological engineered blood vessels.

Tissue engineering has driven significant research in the strive to create a supply of tissues for patient treatment. Cell integration into engineered tissues maximizes functional capabilities, however, issues of rejection remain. Autologous cell sources able to solve this issue are difficult to identify for tissue engineering purposes. Here, we present the efficacy of patient-sourced cells derived from adipose (adipose-derived stem cells, ASCs) and skin tissue (dermal fibroblasts, PtFibs) to build a combined engineered tunica media and adventitia graft, respectively. Patient cells were integrated into our lab's vascular tissue engineering technique of forming vascular rings that are stacked into a tubular structure to create the vascular graft. For the media layer, ASCs were successfully differentiated into the smooth muscle phenotype using angiotensin II followed by culture in smooth muscle growth factors, evidenced by significantly increased expression of αSMA and myosin light chain kinase. Engineered media vessels composed of differentiated ASCs (ASC-SMCs) exhibited an elastic modulus (45.2 ± 18.9 kPa) between that of vessels of undifferentiated ASCs (71.8 ± 35.3 kPa) and control human aortic smooth muscle cells (HASMCs; 18.7 ± 5.49 kPa) (p<0.5). Tensile strength of vessels composed of ASCs (41.3 ± 15.7 kPa) and ASC-SMCs (37.3 ± 17.0 kPa) were higher compared to vessels of HASMCs (28.4 ± 11.2 kPa). ASC-based tissues exhibited a significant increase in collagen content and fiber maturity- both factors contribute to tissue strength and stability. Furthermore, vessels gained stability and a more-uniform single-tubular shape with longer-term 1-month culture. This work demonstrates efficacy of ASCs and PtFibs to create patient-specific vessels.

Comparative Anatomical and Histological study of gall bladder in Mallard (Anas platyrhynchos) and Broiler fowl (Gallus gallus )

The current study was investigated anatomical and histological description of gall bladder of two specious which different in nutrition and life habitat Mallard (Anas platyrhnchos) aquatic life bird, and broiler fowl (Gallus gallus) wild life bird ,used ten bird of each specious ,anatomical result founded the gall bladder is located at the visceral surface right lobe of liver at right side of abdominal cavity, and composed of three parts head, neck and body, gall bladder in both specious appeared with dark green color. Gall bladder of mallard has balloon shape more elongated organ while in Gallus gallus is pear shape, the mean weight of gall bladder in mallard (1.91±0.56 g) , length (3.07±0.505 cm) and width (3.07±0.5 cm ) while broiler fowl weight of gall bladder (8.24±2.88 g), length (3.31±0.8 cm)and width (3.56±1.32 cm ) .Histologically; Gall bladder in mallard has three main layers: tunica mucosa, tunica muscularis and tunica adventitia ,tunica mucosa which lined by simple columnar epithelium non-ciliated with goblet cells and the lamina propria-submucosa composed of loos connective tissue , tunica muscularis was a thick layer of muscles (smooth muscles) and adventitia made of loos connective tissue , while gall bladder of Gallus gallus domesticus has three layer; tunica mucosa, lamina propria -submucosa, tunica muscularis and adventitia , tunica mucosa which lined by simple columnar epithelia non- ciliated without goblet cells , with present lamina propria -submucosa fused with lamina propria ,and thin layer of tunica muscularis and adventitia made of loos connective tissue .

Evaluation of renovation strategies for existing residential districts in Shanghai based on coupling calculation of microclimate and energy consumption

This study aims to analyze the impact of renovation strategies on the air-conditioning load in existing residential districts in Shanghai by using the Grasshopper platform coupled with ENVI-met and EnergyPlus. These strategies include increasing the greening rate (G), improving pavement reflectivity and permeability (P), increasing the reflectivity of external wall coatings (C), increasing roof material reflectivity or applying green roofs (R), and improving the thermal performance of windows (W). The results show that microclimate and weather station data cause a 13.9% maximum deviation in energy consumption simulations. W and R4 significantly reduce the air-conditioning load throughout the year. W contributes to a decrease of 34.8 kWh in the cooling load and 110.4 kWh in the heating load. When the application level of P is low, and that of other strategies is high, the cooling load of the target building reaches its minimum. The minimum cooling load scenario is 302 kWh (25.1%) lower than the maximum. When the application level of G and C is low, other strategies have a high application level, and green roofs are used, the heating load of the target building is minimal. The minimum heating scenario is 386 kWh (29.3%) lower than the maximum.

Abstract P307: What A Difference Hypertension Makes: The Adventitia Hands Off To PVAT For Extracellular Matrix Remodeling As Blood Pressure Rises In The High Fat Fed Dahl SS Rat.

Tunica media extracellular matrix remodeling is well understood to occur in response to elevation of blood pressure, considered a protective response. Remodeling of other tunicas is not well known. We have a long-term hypothesis that perivascular adipose tissue (PVAT) is responsive to hypertension and likely remodels to assist the blood vessel in protection against higher pressures. Here, we used the tunica adventitia and PVAT of the thoracic aorta in measuring extracellular matrix genes from 5 pairs of Dahl SS male rats on 8 or 24 weeks of feeding from weaning on a control (10% fat) or high fat (HF; 60%) diet. These times were picked given relative increases mean arterial blood pressure (mm Hg) in the HF vs control (mmHg increase; 8 week: 14±5; 24 week = 35±8; p&lt;0.05). The adventitia and PVAT were dissected apart, RNA isolated, cDNA synthesized and run on RT2 profiler array kits for ECM and Cell Adhesion genes. Differentially expressed genes (HF 2 fold &gt; Con) were determined in Cytoscape, followed by identification of Hub Genes and construction of a Gene Regulatory network. At 8 weeks on HF diet, the adventitia had 29 upregulated genes (vs Con diet) while the PVAT had none. By contrast, at 24 weeks on diet, the HF adventitia had 3 upregulated genes while PVAT had 47. The top two genes elevated at 8 weeks in adventitia where thrombospondin 1 and collagen 8a1. Surprisingly, at 24 weeks, thrombospondin 1 was one of the three top genes upregulated in PVAT. The following transcription factors were identified as regulators of those genes upregulated in the 8 week adventitia: Adarb1, Fos, Gm10323, Smad3 and Mapk1 . By contrast, the key transcription factors for DEGS in the 24 week PVAT were Stat1, Bcl6B, Tsnax, Pax8, and Jun. Adarb1 (Adenosine deaminase RNA specific B1) was also determined to be a key regulator in PVAT remodeling. These data support that the PVAT responds biologically once blood pressure is elevated.

Cystic adventitial disease van de arteria poplitea: casus en literatuuroverzicht

Cystic adventitial disease of the arteria poplitea: case report and literature review Cystic adventitial disease (CAD) is a relatively rare condition (responsible for 1 in 1,200 cases of calf claudication) with the formation of a mucinous cyst in the tunica adventitia. The arterial, rather than the venous, vascular structures are affected in a relatively young, predominantly male population. Several locations have been described, most of them in the popliteal artery (80-85%). Etiologically, several hypotheses have been put forward, without clear consensus, although the synovial and developmental theories are currently considered the most plausible. The patient’s history generally involves complaints of claudication without the presence of important cardiovascular risk factors. Typically, a spasmodic feeling in the calf with varying degrees of exertion is described, with spontaneous recovery after some period of rest. Of paramount importance is the consideration of CAD in a story of intermittent claudication. A Doppler ultrasound, as well as a CT scan and/or an MRI with associated angiography can all be used for the diagnosis. Surgery with complete excision and interposition of a venous graft is the treatment of choice. The cyst can also be drained by means of a percutaneous ultrasound-assisted needle aspiration, but this is associated with a high need of revision. Percutaneous endovascular treatment with a balloon angioplasty (and possibly stenting) does not show favorable results. Recurrence of CAD after surgical resection is minimal. Recently, several cases have been described with spontaneous resolution of claudication after conservative management without surgical resection need and/or aspiration.

Tracheal tunica adventitia invasion after lobectomy in patients with non-small cell lung cancer

BackgroundFor patients with non-small cell lung cancer, a negative margin status is required for radical pulmonary surgery. Residual disease of the margin has been thoroughly studied in the past few decades. However, the prognostic significance of tracheal tunica adventitia invasion after lobectomy remains unclear. In this study, we aimed to investigate the clinical influence of tracheal tunica adventitia invasion after lobectomy. MethodsWe retrospectively collected the clinical data of 591 patients who consecutively underwent pulmonary lobectomy, including sleeve lobectomy, between 2012 and 2018 at Shanghai Chest Hospital. According to the tracheal tunica adventitia invasion status, we allocated the patients into 2 groups (tracheal tunica adventitia invasion and non-tracheal tunica adventitia). Disease-free and overall survival were evaluated, and we discussed the necessity of radiotherapy in patients with tracheal tunica adventitia. ResultsAfter propensity score matching to balance baseline characteristics, there were 167 individuals in the tracheal tunica adventitia invasion and non-tracheal tunica adventitia groups. In the hazard analysis, we found that tracheal tunica adventitia increased the risk of recurrence (hazard ratio: 0.652; P = .002) and impaired long-term survival (P < .001). Subgroup analysis revealed that tracheal tunica adventitia was an important risk factor, especially when the hilar lymph nodes were positive. In addition, tracheal tunica adventitia invasion promoted extra-thoracic lymph node metastasis. We discovered that radiotherapy did not improve the prognosis of patients in the tracheal tunica adventitia invasion group. ConclusionsAfter lobectomy, tracheal tunica adventitia invasion is a risk factor for non-small cell lung cancer and potentially increases extra-thoracic lymph node metastasis. Moreover, tracheal tunica adventitia invasion is not sensitive to postoperative radiotherapy.

Vaşak (Lynx lynx)’ta Larynx Kıkırdakları, Trachea ve Akciğerler Üzerine Makroanatomik ve Histolojik Bir Çalışma

In this study the larynx, trachea, and lungs of one 1.5-year-old adult female lynx (Lynx lynx) were examined. The macro anatomical and histological structure of the larynx cartilages, trachea, and lungs were tried to be revealed by dissection and measurements. It was determined that the trachea had 48 cartilage rings (cartilago trachealis) up to the bifurcatio trachealis, the diameters of which narrow as they approach the lungs. The total tracheal length was 172.36 mm. It was seen that the cross-section of the lynx trachea resembled a circle. The hyaline cartilage structure surrounding the trachea was determined. A muscle structure called musculus transversus trachea, which closes the open ends of this cartilage and surrounds the cartilage from the outside, was detected. It was determined that the trachea consisted of tunica mucosa, submucosa, and tunica adventitia layers. The pulmo sinister in the lynx lung consisted of two main lobes, lobus cranialis, and lobus caudalis. Lobus cranialis was also divided among itself as pars cranialis and pars caudalis. Pulmo dexter was divided into four main lobes as lobus cranialis, lobus medius, lobus caudalis, and lobus accessorius. It was determined that there was connective tissue capsule surrounding the lung, respiratory bronchioles, alveoli, intraalveolar septum, and abundant blood vessels. In intraalveolar septum; capillaries, erythrocytes were determined. Type I and type II pneumocytes were seen covering the alveolar surface. In addition, it was determined that there were macrophages in the alveolar sacs.

Histologic changes of porcine portal vein anastomosis after electrochemotherapy with bleomycin

Electrochemotherapy (ECT11Electrochemotherapy.) is used for treatment of unresectable abdominal malignancies. This study aims to show that ECT of porcine portal vein anastomosis is safe and feasible in order to extend the indications for margin attenuation after resection of locally advanced pancreatic carcinoma. No marked differences were found between the control group and ECT treated groups. Electroporation thus caused irreversible damage to the vascular smooth muscle cells in tunica media that could bedue to the narrow irreversible electroporation zone that may occur near the electrodes, or due to vasa vasorum thrombosis in the tunica externa. Based on the absence of vascular complications, and similar histological changes in lienal veinanastomosis, we can conclude that ECT of portal vein anastomosis is safe and feasible.

Ultraviolet-induced mechanical augmentation of the degraded porcine aortic adventitia: Its significance for preventing aneurysmal rupture

In the previous studies, we have shown that the tunica adventitia of porcine abdominal aorta could be mechanically reinforced by irradiating it with ultraviolet A (UV-A) rays to promote the photocrosslinking of constitutive collagen, and we have proposed the method as a procedure to prevent or delay abdominal aortic aneurysm (AAA) ruptures. We have also demonstrated that UV irradiation-induced mechanical augmentation despite the degradation of the adventitia through collagenolysis in vitro. Considering that elastolysis is equally a relevant event in the pathogenesis of AAA, the degradation of elastin was also investigated in the present study. A total of 50 porcine aortas were used in the study. All processed samples were evaluated in a mechanical tester before and after degradation and/or irradiation. The adventitial layer was isolated and subjected to elastase for either 1 – 48 h. We found that both elastin and collagen were digested by elastase, with the former being completely digested after 48 h. The samples degraded for 1 h were subsequently irradiated with UV-A (365 nm) in the presence of riboflavin as a photoinitiator, a process that induced an enhancement of the strength and stiffness of the tissue. This is an indication that a partly degenerated aortic wall, like that in an aneurysmal region, can be reinforced mechanically by UV irradiation, possibly to the extent of delaying, or preventing altogether, the wall’s rupture. It appears important to irradiate the wall as early as possible.

The Effect of Products Released from the Structural Materials of a Spacecraft on the Optical Properties of Its Thermal Control Coatings

In this paper, we report on our experimental findings regarding the release of easily condensing substances from certain structural materials utilized in spacecraft, and we evaluate the impact of thin condensate films on the integral optical coefficients of external thermal control coatings (TCCs) of spacecraft. To simulate the space environment and solar radiation, the experiments were conducted in a vacuum. We found that the flux densities of the components released from the materials’ surfaces reach 5.4 × 10–7 g cm–2 s–1 and exhibit an exponential decrease over time. Furthermore, thin condensate films with a thickness of 100 Å can significantly degrade the integral optical coefficients of TCCs by tens of percent. These effects can alter the heat balance of the spacecraft. The experimental research methods used in this study can be applied to a broad range of materials, and the results have implications for the design and construction of various types of spacecraft.

Gross and histological examination of Wharton's Jelly in the equine umbilical cord

Wharton's jelly (WJ) is fundamental for the well-being of the fetus, binding to the umbilical vessels and protecting them from twisting and compression. Gross and microscopic studies have been undertaken on the umbilical cord (UC) of human placentae in both normal and high-risk pregnancies, however there is limited research on equine UC. The aim of this study was to describe microscopically and immunohistochemically the equine UC in normal pregnancies, with particular attention to WJ. Forty-seven healthy mares, with no complications during pregnancy, admitted to the hospital for attending delivery were enrolled. Clinical data was collected at foaling on foal health and placental characteristics. UC samples were collected from three sites (amniotic, allantoic and in the region of vein anastomosis) for histology. The thickness of different layers of arteries and veins and WJ in different UC portions were measured (μm). Wharton's Jelly was weighted (g) and its sections were stained with Masson's trichrome, orcein technique and silver impregnation. Immunohistochemistry was undertaken using antibodies raised-against collagen type I, V, VI and fibrillin. Forty-seven UCs, from 19 colt and 28 filly foals, were analyzed for WJ weight and 8/47 UCs were examined histologically. Warton's jelly was only found in the amniotic portion of the UC closest to the foal's abdomen. The weight of WJ (4.0 ± 3.3 g) did not vary between colts and fillies and it was not correlated with any of the clinical or UC parameters measured. The tunica media of arteries and veins was thicker in the amniotic portion of the UC, as described in human UCs in late pregnancy. This finding could be an adaptation to aid in resisting compression because of fetal movements and UC twisting. The umbilical vein was thicker than the umbilical arteries in the tunica media and tunica adventitia in the sections examined throughout the length of the cord. This preliminary study describes gross and histological WJ's structure in the equine species. However, further studies are required to better characterize UC's changes throughout pregnancy and in the presence of mare's or fetal disease.

Hydrogel Coating Optimization to Augment Engineered Soft Tissue Mechanics in Tissue-Engineered Blood Vessels.

Tissue engineering has the advantage of replicating soft tissue mechanics to better simulate and integrate into native soft tissue. However, soft tissue engineering has been fraught with issues of insufficient tissue strength to withstand physiological mechanical requirements. This factor is due to the lack of strength inherent in cell-only constructs and in the biomaterials used for soft tissue engineering and limited extracellular matrix (ECM) production possible in cell culture. To address this issue, we explored the use of an ECM-based hydrogel coating to serve as an adhesive tool, as demonstrated in vascular tissue engineering. The efficacy of cells to supplement mechanical strength in the coating was explored. Specifically, selected coatings were applied to an engineered artery tunica adventitia to accurately test their properties in a natural tissue support structure. Multiple iterations of three primary hydrogels with and without cells were tested: fibrin, collagen, and gelatin hydrogels with and without fibroblasts. The effectiveness of a natural crosslinker to further stabilize and strengthen the hydrogels was investigated, namely genipin extracted from the gardenia fruit. We found that gelatin crosslinked with genipin alone exhibited the highest tensile strength; however, fibrin gel supported cell viability the most. Overall, fibrin gel coating without genipin was deemed optimal for its balance in increasing mechanical strength while still supporting cell viability and was used in the final mechanical and hydrodynamic testing assessments. Engineered vessels coated in fibrin hydrogel with cells resulted in the highest tensile strength of all hydrogel-coated groups after 14 d in culture, demonstrating a tensile strength of 11.9 ± 2.91 kPa, compared to 5.67 ± 1.37 kPa for the next highest collagen hydrogel group. The effect of the fibrin hydrogel coating on burst pressure was tested on our strongest vessels composed of human aortic smooth muscle cells. A significant increase from our previously reported burst pressure of 51.3 ± 2.19 mmHg to 229 ± 23.8 mmHg was observed; however, more work is needed to render these vessels compliant with mechanical and biological criteria for blood vessel substitutes.

Building a Scaffold for Arteriovenous Fistula Maturation: Unravelling the Role of the Extracellular Matrix

Vascular access is the lifeline for patients receiving haemodialysis as kidney replacement therapy. As a surgically created arteriovenous fistula (AVF) provides a high-flow conduit suitable for cannulation, it remains the vascular access of choice. In order to use an AVF successfully, the luminal diameter and the vessel wall of the venous outflow tract have to increase. This process is referred to as AVF maturation. AVF non-maturation is an important limitation of AVFs that contributes to their poor primary patency rates. To date, there is no clear overview of the overall role of the extracellular matrix (ECM) in AVF maturation. The ECM is essential for vascular functioning, as it provides structural and mechanical strength and communicates with vascular cells to regulate their differentiation and proliferation. Thus, the ECM is involved in multiple processes that regulate AVF maturation, and it is essential to study its anatomy and vascular response to AVF surgery to define therapeutic targets to improve AVF maturation. In this review, we discuss the composition of both the arterial and venous ECM and its incorporation in the three vessel layers: the tunica intima, media, and adventitia. Furthermore, we examine the effect of chronic kidney failure on the vasculature, the timing of ECM remodelling post-AVF surgery, and current ECM interventions to improve AVF maturation. Lastly, the suitability of ECM interventions as a therapeutic target for AVF maturation will be discussed.

A Dual-Core Surface Plasmon Resonance-Based Photonic Crystal Fiber Sensor for Simultaneously Measuring the Refractive Index and Temperature

In this correspondence, a new photonic crystal fiber biosensor structure on the basis of surface plasmon resonance is proposed for the measurement of the refractive index (RI) and TSM temperature simultaneously. In this design, the central and external surface of the biosensor structure are coated with thin gold film. A hole adjacent to the inner gold film is filled with temperature-sensitive material (TSM). With the implementation of internal and external gold coatings along with TSM, the biosensor achieves the measurement of the RI and temperature with two disjoint wavelength coverage. Numerical simulations and calculation results illustrate that the average wavelength sensitivity of the biosensor structure, respectively, achieves 7080 nm/RIU and 3.36 nm/°C with RI coverage from 1.36 to 1.41 and temperature coverage from 0 to 60 °C. Moreover, benefiting from realization of different wavelength regions in RI and temperature sensing, it is believed that the proposed biosensor structure for the measurement of the RI and temperature will have range applications in the fields of medical diagnostics and environmental assessments.

#3197 A NOVEL INVESTIGATION OF AVF WITH A SECOND HARMONIC GENERATION MICROSCOPY IN PATIENTS WITH END STAGE RENAL DISEASE

Abstract Background and Aims The population of patients with end-stage renal disease is rapidly growing and hemodialysis (HD) remains the most common treatment option. In clinical practice, the formation of arteriovenous fistulas (AVFs) is considered a priority in order to ensure optimal vascular access for HD patients. One of the complications in the formation of AVF is the hyperplasia of the neointimal layer of the vein, which leads to the failure of the fistula. The impact of the arrangement of collagen fibers in the veins of AVFs is little studied and opens wide opportunities for investigations. The structural tissue can be imaged with polarimetric nonlinear microscopy. Collagen fibers have a non-centrosymmetric structure, so they can be effectively imaged by second harmonic generation (SHG) microscopy [1]. The polarimetric nonlinear microscopy, exploiting the multidimentional tensor nature of light-matter interactions, is emerging as a valuable research tool in biomedical investigations and applications to digital pathology, and is only now becoming technically feasible for potential clinical translation [2,3]. This proposal represents a novel application of multimodal polarimetric nonlinear microscopy in histopathology, and biomedical imaging. The aim of this study is to determine the influence of the arrangement of collagen fibers in veins on the formation efficiency of AVFs by using the innovative method of nonlinear SHG microscopy. Method In this prospective study, we first used a novel SHG microscopy method to investigate AVFs venous intima hyperplasia. V. Cephalica segment is being obtained during arteriovenous fistula formation surgery from patients with end stage renal disease and after the removal of aneurysmatic or fibrotic AVF. Cross-sections of venous specimens are being fixed in 10% buffered formalin and stained with hematoxylin and eosin (H&amp;E). Further, sample investigation is being performed in Laser Research Centre, Vilnius University using a home-built multiphoton laser-scanning microscope. The investigation is being performed with the permission of Lithuanian Biomedical Research Ethics Committee. Results We determined the arrangement of collagen fibers in veins before AVF formation and after the removal of aneurysmatic AVFs. It was observed that tunica intima of V. Cephalica is dominated both by endothelial cells and connective tissue made up of high-density collagen fibers. Whereas tunica adventitia consists mainly of collagen fibers. Collagen in tunica intima and adventitia are found to be highly noncentrosymmetric. Thus a strong SHG signal, resulting in high-contrast structural visualization of the V. Cephalica segment is generated. Conclusion Our initial investigations of AVF show clearly visible collagen fibers. The future work will focus on the structural changes of collagen fibers in the vein intimal hyperplasia. Further investigations need to be done to create artificial intelligence-based identification of new predictive collagen markers.

Aldehyde Dehydrogenase, a Marker of Normal and Malignant Stem Cells, Typifies Mesenchymal Progenitors in Perivascular Niches.

Innate mesenchymal stem cells exhibiting multilineage differentiation and tissue (re)generative-or pathogenic-properties reside in perivascular niches. Subsets of these progenitors are committed to either osteo-, adipo-, or fibrogenesis, suggesting the existence of a developmental organization in blood vessel walls. We evaluated herein the activity of aldehyde dehydrogenase, a family of enzymes catalyzing the oxidation of aldehydes into carboxylic acids and a reported biomarker of normal and malignant stem cells, within human adipose tissue perivascular areas. A progression of ALDHLow to ALDHHigh CD34+ cells was identified in the tunica adventitia. Mesenchymal stem cell potential was confined to ALDHHigh cells, as assessed by proliferation and multilineage differentiation in vitro of cells sorted by flow cytometry with a fluorescent ALDH substrate. RNA sequencing confirmed and validated that ALDHHigh cells have a progenitor cell phenotype and provided evidence that the main isoform in this fraction is ALDH1A1, which was confirmed by immunohistochemistry. This demonstrates that ALDH activity, which marks hematopoietic progenitors and stem cells in diverse malignant tumors, also typifies native, blood vessel resident mesenchymal stem cells.

Failure analysis in buried ductile iron pipelines: A study of leakage in drinking water distribution systems

Severely external corrosion has occurred on the ductile iron pipelines tube, which caused leakage and affected the drinking water supply of numerous people. The tube was made up of QT400 ductile iron with external and internal protective coatings. The service environment was the underground of a riverbed close to residential areas. In this study, this failure and its mechanism were studied through field investigations and laboratory experiments. The penetration rate of the localized corrosion is twice higher than that of uniform corrosion. It is perceived that DC stray current causes the localized corrosion, which results in smooth and black-deposits-covered morphology. Microorganisms, especially sulfate-reducing bacteria (SRB) in the soil plays an auxiliary role in the failure process. Additionally, the micro-galvanic corrosion between graphite and matrix promotes the failure. This study shows that an in-depth investigation on the stray-current corrosion in buried cast iron pipes is critical, although sacrificial anodes have been adopted.