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This article defines immunophenotypes of stromal inflammatory and endothelial cells and fibroblasts 3 months after augmentation of the peri-implant soft tissue using a porcine cross-linked collagen matrix (VCMX). Peri-implant soft tissue samples were obtained from 12 patients at the lining mucosa (LM)-masticatory mucosa (MM) junction before (1) and 3 months after (2) augmentation. Immu-nohistochemical stains were performed to identify inflammatory cells (T [CD3] and B [CD20] lymphocytes, plasma cells [CD138]), macrophages (CD68-proinflammatory, CD163-anti-inflammatory/ reparative), endothelial cells (CD31, CD34), and fibroblasts (CD90, TE-7). Differences in the mean positively stained cells pre- and postaugmentation were analyzed by Wilcoxon signed-rank test. CD31+ endothelial cells showed increased mean numbers in MM2 compared to MM1 (P = .025) and in LM2 compared to LM1 (P = .047). CD163+ anti-inflammatory macrophages showed higher mean numbers in MM2 than in MM1 (P = .021) and in LM2 than in LM1 (P = .012). All other cell phenotypes showed nonsignificant changes between pre- and postaugmentation. This molecular study provides novel insight on the frequency of stromal cell phenotypes in the wound healing process at 3 months postaugmentation with VCMX, with anti-inflammatory CD163+ macrophages being predominant. This should be further investigated to help find novel therapeutic approaches to modulate and promote the VCMX-related healing process. [ABSTRACT FROM AUTHOR]

When developing, the mandible presents great plasticity and contains condensed mesenchymal cells that develops into Meckel's cartilage, of which the anterior part forms the mandibular symphysis. Mandible human development studies focus on investigating whether the beginning of mandibular fusion in fetal period is related to symphysis ossification and the tensions imposed on it, considering that tongue movements, mouth opening, and closing can be seen in fetuses. This research analyses tissue modifications during human mandibular symphysis growth using light and scanning electron microscopy to relate them to its functional structure. The study sample consisted of 12 human fetuses distributed into two groups: Group I (GI) of 10–14 weeks old and Group II (GII) of 20–24 weeks old. Fragments of mandibular symphysis were removed en bloc together with the surrounding tissues to preserve the relation with adjacent structures. Decalcified specimens were prepared in semi‐serial coronal sections 5‐μm‐thick and stained with hematoxylin and eosin, Masson՚s trichrome, Verhoeff, and Sirius red for histological analysis with light microscopy. Collagen fibers Type I or III and elastic fibers were quantified by volume fraction (Vv). Coronal sections of the GI and GII symphyseal region were submitted to scanning electron microscopy. Comparison between groups used independent t‐test. Our study presents the different endochondral ossification stages in the anterior part of Meckel's cartilage in GI. Both groups showed abundantly vascularized mesenchymal tissue with intense cellular activity forming the mandibular symphysis, such as a source of new osteoblasts adjacent to the newly deposited bone matrix. Scanning electron microscopy analysis revealed an invasion of the bony trabecula in the transverse direction from the hemimandible, rectilinear in GI and sinuous in GII due to interdigitating bone process, promoting its ossification. In collagen Vv analysis was verified a prevalence of type I in GII and type III in GI, indicating a proportional relation between maturation and tissue arrangement. Functionally, the collagen and elastic fibers in the mandibular symphysis were arranged in a pantographic network, and the fibrillar interconnectivity clearly contributes to resilience capacity and efficiency of the force transfer. This study inferred the functional significance of the knowledge about the tissue composition of mandibular symphysis, and the importance of this tissue for surrounding structures. The mesenchymal tissue of mandibular symphysis participates in bone growth process, revealing an adaptation mechanism of mandibular symphysis in the fetal period investigated. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of the estrogen depression during orthodontic tooth movement on alveolar bone microarchitecture and periodontal ligament. Female Wistar rats were divided into two groups, one consisting of non‐ovariectomized animals subjected to orthodontic tooth movement, and one comprising ovariectomized animals subjected to orthodontic tooth movement. Micro‐CT assessment of bone volume to total volume (BV/TV), total porosity, trabecular thickness (Tb.Th), trabecular number (Tb.N), and trabecular separation (Tb.Sp) in the alveolar bone of the orthodontically moved tooth was performed. Histomorphometric analyses were made in the periodontal ligament, and immunoexpression of RANK, RANKL, OPG, and TUNEL were quantified. Orthodontic tooth movement in the group of ovariectomized rats was faster than in non‐ovariectomized animals. The alveolar bone area showed lower values of BV/TV and trabecular thickness, and higher bone porosity and trabeculae numbers in the ovariectomized rats. Histological analyses in the ovariectomized group revealed an increase in collagen fibers in the periodontal ligament. The apoptotic cell counts in the periodontal ligament were higher in the group of ovariectomized rats than in the sham‐operated rats. Ovariectomy resulted in an increase in tooth movement and alteration of the alveolar bone microstructure in the first 7 day of orthodontic tooth movement, and in the presence of apoptotic cells in the periodontal ligament. [ABSTRACT FROM AUTHOR]

The present study was executed at Department of Veterinary Anatomy, College of Veterinary Science, Sri Venkateswara Veterinary University, Tirupati, Andhra Pradesh, India during the period of July, 2020 to October, 2021 to find the possible differences in histology of teat among domestic animals. The study was conducted on teat of domestic animals i.e., 6 adult buffalo, 6 cattle, 15 sheep, 15 goats, 6 dogs and 6 pigs. The wall of the teat consisted of three layers in buffalo, cattle, sheep, goat and pig i.e., outer skin, middle muscular and inner connective tissue layer. But in dog only two layers were present i.e., outer skin and inner fibromuscular layer. Each teat consisted of single teat sinus in buffalo, cattle, sheep and goat, whereas in pig each teat showed two teat sinuses and eleven sinuses in dog. In buffalo and cattle, isolated clusters of glandular structures were seen between the smooth muscle fibers which were absent in sheep, pig and dog. Further, in sheep and goat, accessory glands were noted in the dermis and in middle layer. Sweat glands were noticed only in sheep and goat. In cattle and pig, hair follicles were not distinct and they were surrounded by numerous sebaceous glands. The number of collagen fibers in dermis of teat were more dense in cattle than other domestic animals. Elastic fibers were numerous in dog and moderate in the dermis of teat in buffalo, cattle, sheep and very few in goat. [ABSTRACT FROM AUTHOR]

[Display omitted] Advanced numerical simulations of the mechanical behavior of human skin require thorough calibration of the material's constitutive models based on experimental ex vivo mechanical tests along with images of tissue microstructure for a variety of biomedical applications. In this work, a total of 14 human healthy skin samples and 4 additional scarred skin samples were experimentally analyzed to gain deep insights into the biomechanics of human skin. In particular, second harmonic generation (SHG) microscopy was used to extract detailed images of the distribution of collagen fibers, which were subsequently processed using a three-dimensional Fourier transform-based method recently proposed by the authors to quantify the distribution of fiber orientations. Mechanical tests under both biaxial and uniaxial loading were performed to calibrate the relevant mechanical parameters of two widely used constitutive models of soft fiber-reinforced biological tissues that account for non-symmetrical fiber dispersion. The calibration of the models allowed us to identify correlations between the mechanical parameters of the constitutive models considered. Constitutive models for soft collagenous tissues can accurately reproduce the complex nonlinear and anisotropic mechanical behavior of skin. However, a comprehensive analysis of both microstructural and mechanical parameters is still missing for human skin. In this study, these parameters are determined by combining biaxial mechanical tests and SHG stacks of collagen fibers on ex vivo healthy human skin samples. The constitutive parameters are provided for two widely used hyperelastic models and enable accurate characterization of skin mechanical behavior for advanced numerical simulations. [ABSTRACT FROM AUTHOR]

Allogeneic tendon grafts are seriously demand in knee joint plastic surgery. The novel method of tendon cryopreservation, including sterilization with supercritical carbon dioxide, was developed in N.V. Sklifosovsky Research Institute for Emergency Cryopreserved tendons retain their normal fiber structure without significant loss of mechanical properties. At the next stage it was necessary to evaluate cryopreserved tendons′ integration inside bone canal in experimental animals.The aim of study. To evaluate morphologic changes of autologous and allogeneic tendons inside the femur in rats and to determine the effect of tendon transplantation on the physical activity.Material and methods. The study was conducted on white inbreed male rats. Three groups of animals were formed: the control group (animals without tendon transplantation), the 1st experimental group – animals with autologous tendon transplantation, the 2nd experimental group – animals with allogeneic tendon transplantation. In animals of the experimental groups the through channel was formed in the distal metaepiphysis of the femur and a tail tendon graft 0.5 x 0.1 cm was placed there. To assess the physical activity of the animals, we studied maximum distance that the animals could run 3 and 6 weeks after transplantation was determined, using treadmill test. The graft structure was evaluated on histological preparations in transmitted light, stained with hematoxylin-eosin and Van Gieson′s stain. To assess the preservation of collagen fibers we checked the autofluorescence intensity of collagen.Results. According to the treadmill test, the distance run by the animals of both experimental groups did not significantly differ from the values in the control group. Histological analysis after 3 weeks in both experimental groups revealed signs of fibers′ decomposition in the absence of inflammatory infiltration and maintaining close contact with bone trabeculae. The autofluorescence intensity of the collagen fibers in grafts corresponded to normal or was close to normal. After 6 weeks, the animals of both experimental groups revealed areas of graft fusion with their own bone, Sharpe fibers were actively formed. In both groups, numerous small vessels with diameters up to 10 microns were detected in the area of tendon-bone contact. Infiltration of grafts by inflammatory cells was absent or very insignificant, active migration of fibroblasts to the tendon area was also not observed. In both groups, tendon grafts had areas where fiber decompactization was observed. In the area of contact with the bone, the autofluorescence of tendon fibers was sharply increased, which indicates the chemical cleavage of collagen. At 3 and 6 weeks after transplantation the effect of fixation (integration) of the tendon with bone tissue was observed in both experimental groups.Conclusions. Allogeneic tendon grafts did not cause a pronounced inflammatory or immune reaction in experimental animals. 6 weeks after transplantation of autologous and allogeneic tendons, the integration of grafts inside the femoral canal was observed. Cryopreserved allogeneic tendons were able to integrate into the body's own tissues without pronounced structural and functional disorders. According to the treadmill test, the distance covered by the animals of both experimental groups did not differ statistically significantly from the values in the control group (without tendon transplantation) after 3 and 6 weeks

Background: The negative effects of skin aging are primarily related to the destruction of dermal architectural structure. More specifically, this includes changes in the spatial arrangement of collagen, elastin fibers, mucopolysaccharides, proteoglycans, and ground substances. Aims: The purpose of this study is to investigate the histologic effects of dermal and subdermal tissue after a controlled single treatment with radiofrequency (RF) macroneedling. This therapy provides a controlled, localized, thermal effect on the dermis whereby triggering the body's own healing processes of extracellular matrix remodeling. Clinically benefits include skin tightening. Methods: Biopsies were obtained for histologic evaluation from four patients (n = 4), 4 weeks after completing a single RF macroneedling facial treatment. Results: Age‐related changes of the dermal and subdermal architecture were observed at baseline. After treatment, all biopsies demonstrated an increase in epidermal cells, collagen, elastin, fibroblasts, vasculature, and a decrease in inflammatory cells. Conclusions: The results of this histologic study confirm a significant "subsurfacing" thermal effect from the noncoagulative ascendant thermal injury. The obtained results characterize RF macroneedling therapy as an effective method for correcting age‐related changes in facial skin. [ABSTRACT FROM AUTHOR]

The intact and healthy skin forms a barrier to the outside world and protects the body from mechanical impact. The skin is a complex structure with unique mechano-elastic properties. To better direct the design of biomimetic materials and induce skin regeneration in wounds with optimal outcome, more insight is required in how the mechano-elastic properties emerge from the skin's main constituents, collagen and elastin fibers. Here, we employed two-photon excited autofluorescence and second harmonic generation microscopy to characterize collagen and elastin fibers in 3D in 24 human dermis skin samples. Through uniaxial stretching experiments, we derive uni-directional mechanical properties from resultant stress-strain curves, including the initial Young's modulus, elastic Young's modulus, maximal stress, and maximal and mid-strain values. The stress-strain curves show a large variation, with an average Young's modules in the toe and linear regions of 0.1 MPa and 21 MPa. We performed a comprehensive analysis of the correlation between the key mechanical properties with age and with microstructural parameters, e.g., fiber density, thickness, and orientation. Age was found to correlate negatively with Young's modulus and collagen density. Moreover, real-time monitoring during uniaxial stretching allowed us to observe changes in collagen and elastin alignment. Elastin fibers aligned significantly in both the heel and linear regions, and the collagen bundles engaged and oriented mainly in the linear region. This research advances our understanding of skin biomechanics and yields input for future first principles full modeling of skin tissue. [ABSTRACT FROM AUTHOR]

Relevance. The structural features of the collagen skeleton, including constitutional ones, suggest the ability of the menisci to withstand excessive mechanical stress and injury.Purpose – to study the differences in the collagen skeleton of the knee menisci in male corpses of different types of sexual dimorphism according to J. Tanner.Materials and methods. The menisci of the knee joints (medial and lateral) from the corpses of 84 men aged 22–74 years of different types of sexual dimorphism according to J. Tanner were studied. Microslides of the menisci at the level of the body, anterior and posterior horns, stained according to the method of K. Masson, were made. The location is described and the percentage of collagen fibers of the fibrous cartilage of the menisci of the knee joints with surrounding formations per unit area of unchanged cartilage tissue at the level of the horns and body of the menisci is calculated.Results. The collagen fibers of the body of both menisci of men are located in parallel, forming the central, upper and lower middle and superficial layers. In the horns, collagen fibers are located chaotically, which leads to “smoothing” of the boundaries. A minimal amount of collagen was found in the central layer of both horns and the body of the meniscus compared to the superficial layers. The maximum values of the percentage of collagen in the central layer are characteristic of the body, the minimum – for the posterior horn of the menisci. Low percentages of collagen in the dorsal horn are due to the andromorphic type.Conclusion. The andromorphic type of sexual dimorphism according to J. Tanner in men is a predisposition factor to damage to the menisci of the knee joints.

Despite recent improvements in medical imaging, the final diagnosis and biopathologic characterization of breast cancers currently still requires biopsies. Ultrasound is commonly used for clinical examination of breast masses. B-Mode and shear wave elastography (SWE) are already widely used to detect suspicious masses and differentiate benign lesions from cancers. But additional ultrasound modalities such as backscatter tensor imaging (BTI) could provide relevant biomarkers related to tissue organization. Here we describe a 3-D multiparametric ultrasound approach applied to breast carcinomas in the aims of (i) validating the ability of BTI to reveal the underlying organization of collagen fibers and (ii) assessing the complementarity of SWE and BTI to reveal biopathologic features of diagnostic interest. Three-dimensional SWE and BTI were performed ex vivo on 64 human breast carcinoma samples using a linear ultrasound probe moved by a set of motors. Here we describe a 3-D multiparametric representation of the breast masses and quantitative measurements combining B-mode, SWE and BTI. Our results reveal for the first time that BTI can capture the orientation of the collagen fibers around tumors. BTI was found to be a relevant marker for assessing cancer stages, revealing a more tangent tissue orientation for in situ carcinomas than for invasive cancers. In invasive cases, the combination of BTI and SWE parameters allowed for classification of invasive tumors with respect to their grade with an accuracy of 95.7%. Our results highlight the potential of 3-D multiparametric ultrasound imaging for biopathologic characterization of breast tumors. [ABSTRACT FROM AUTHOR]

The relationship between the small intestine's muscular membrane structure of chickens and the autonomous regulation type was investigated. Based on electrocardiographic and variational pulsometric studies, adult laying hens of the Isa-Brown breed were divided into two groups: sympathotonic (ST) and sympathonormotonic (ST-NT). The volume of individual layers and the entire muscle membrane, as well as the volume of connective tissue fibers located in it, was determined in the small intestine of the hens. In general, the relationship between morphological parameters and the autonomous regulation type is similar throughout the whole intestine, but it has certain peculiarities in different intestine parts. An increase in the volume of both the circumferential and longitudinal layers of the intestinal muscular membrane accompanies an increase in sympathetic tonus. This pattern is typical for both groups. The ratio between these layers varies along the intestinal wall: the share of the longitudinal layer increases while that of the circumferential layer decreases. Accordingly, the average volume of the entire small intestine's muscular membrane in ST and ST-NT chickens differs by 590.6 mm3, and the total volume by 1771.7 mm3 . Increased sympathetic tonus also contributes to a more significant number of collagen fibers in the circular layer of the muscle membrane. In the average values of the small intestine, its superiority over the longitudinal layer is 5.6 % in ST chickens and 3.4 % in ST-NT chickens. Regarding absolute values of elastic fiber volume, no group of birds has a complete advantage along the small intestine. However, the average values of this section are still dominated by ST chickens, which outnumber the other group by 15.3 mm3 in the circumferential layer and by 11.7 mm3 in the longitudinal layer of the muscle membrane. Birds with persistent sympathotonia also have more collagen fibers per 1 mm3 muscle membrane. Regarding average small intestine parameters, ST-NT chickens demonstrate a lower value (0.005 mm3 ). However, regarding the number of elastic fibers alone, ST-NT chickens already occupy a dominant position, and the difference between the two groups decreases to 0.004 mm3 . The established muscle membrane's morphological features indicate its plasticity in adapting the intestinal wall to the autonomous regulation peculiarities. [ABSTRACT FROM AUTHOR]

Objective: We investigated the potential of dual-energy computed tomography (DECT) radiomics in assessing cancer-associated fibroblasts in clear cell renal carcinoma (ccRCC). Methods: A retrospective analysis was conducted on 132 patients with ccRCC. The arterial and venous phase iodine-based material decomposition images (IMDIs), virtual non-contrast images, 70 keV, 100 keV, and 150 keV virtual monoenergetic images, and mixed energy images (MEIs) were obtained from the DECT datasets. On the Radcloud platform, radiomics feature extraction, feature selection, and model establishment were performed. Seven radiomics models were established using the support vector machine. The predictive performance was evaluated by utilizing receiver operating characteristic and the area under the curve (AUC) was calculated. Nomograms were constructed. Results: The combined model demonstrated high efficiency in evaluating pseudocapsule thickness with AUC, specificity, and sensitivity of 0.833, 0.870, and 0.750, respectively in the validation set, surpassing those of other models. The precision, F1-score, and Youden index were also higher for the combined model. For evaluating the number of collagen fibers, the combined model exhibited the highest AUC (0.741) among all models, with a specificity of 0.830 and a sensitivity of 0.330. The AUC in the 150 kv model and IMDI model were slightly lower than those in the combined model (0.728 and 0.710, respectively), with corresponding sensitivity and specificity of 0.560/0.780 and 0.670/0.830. The nomogram exhibited that Rad-score had good prediction efficiency. Conclusion: DECT radiomics features have significant value in evaluating the interstitial fibers of ccRCC. The combined model of IMDI + MEI exhibits superior performance in assessing the thickness of the pseudocapsule, while the combined, 150 keV, and IMDI models demonstrate higher efficacy in evaluating collagen fiber number. Radiomics, combined with imaging features and clinical features, has excellent predictive performance. These findings offer crucial support for the clinical diagnosis, treatment, and prognosis of ccRCC and provide valuable insights into the application of DECT. [ABSTRACT FROM AUTHOR]

Abstract Background and purpose Renal cell carcinoma (RCC) is a heterogeneous group of cancers. The collagen fiber content in the tumor microenvironment of renal cancer has an important role in tumor progression and prognosis. A radiomics model was developed from dual-energy CT iodine maps to assess collagen fiber content in the tumor microenvironment of ccRCC. Methods A total of 87 patients with ccRCC admitted to our hospital were included in this retrospective study. Among them, 59 cases contained large amounts of collagen fibers and 28 cases contained a small amount of collagen fibers. We established a radiomics model using preoperative dual-energy CT scan Iodine map (IV) imaging to distinguish patients with multiple collagen fibers from those with few collagen fibers in the tumor microenvironment of ccRCC. We extracted features from dual-energy CT Iodine map images to evaluate the effects of six classifiers, namely k-nearest neighbor (KNN), support vector machine (SVM), extreme gradient boosting (XGBoost), random forest (RF), logistic regression (LR), and decision tree (DT). The effects of the models built based on the dynamic and venous phases are also compared. Model performance was evaluated using quintuple cross-validation and area under the receiver operating characteristic curve (AUC). In addition, a clinical model was developed to assess the clinical factors affecting collagen fiber content. Results Compared to KNN, SVM, and LR classifiers, RF, DT, and XGBoost classifiers trained with higher AUC values, with training sets of 0.997, 1.0, and 1.0, respectively. In the validation set, the highest AUC was found in the SVM classifier with a size of 0.722. In the comparative test of the active and intravenous phase models, the SVM classifier had the best effect with its validation set AUC of 0.698 and 0.741. In addition, there was a statistically significant effect of patient age and maximum tumor diameter on the collagen fiber content in the tumor microenvironment of kidney cancer. Conclusion Radionics features based on preoperative dual-energy CT IV can be used to predict the amount of collagen fibers in the tumor microenvironment of renal cancer. This study better informs clinical prognosis and patient management. Iodograms may add additional value to dual-energy CTs.

Flexible electric heaters with softness, comfort and heating performance have application prospects in the fields of life and health, medical security and so on. In this study, by taking advantage of the soft and comfortable properties of leather itself, collagen fibers and carbon nanotubes (CNTs) are composited through zirconium ion (Zr4+) coordination and complexation. The composition, microstructure and Joule heating performance of the prepared flexible conductive leather (CNTs@Zr@OTL) are investigated in detail. The characterisation results prove the (Zr4+) coordination effect and the successful preparation of CNTs@Zr@OTL. At the same time, it has a resistance of about 250 Ω, a shrinkage temperature (Ts) of about 75°C, mechanical property of about 8 MPa, 60 h strong biodegradability and Joule heating of about 65°C under 15 V DC voltage. The obtained product can be further designed as a flexible Joule heating heater (Jhh) with softness, comfort as well as conductivity, and excellent Joule heating performance, and its practical application effect in heating wrists, fingers, joints and car seats is explored, as well as the heating effect under the actual movement of human body such as squatting, sitting and walking. This work provides an idea and method for the intelligent interaction of flexible heaters. [ABSTRACT FROM AUTHOR]

Ovarian tissue transplantation makes it possible to restore fertility; however, the success of this technique depends on the transplant region used. Therefore, this study aimed to evaluate the effect of two subcutaneous regions on canine ovarian transplantation, pinna (Pi) and neck (Ne), for 7 and 15 days. Ovaries collected by ovariosalpingohysterectomy were fragmented using a punch device. Fresh fragments were fixed, and the others were immediately grafted onto the animal itself in the Pi and Ne regions for 7 and 15 days. Recovered fragments were evaluated for histology (morphology, development and stromal density), picrosirius (collagen fibers), and immunohistochemistry (fibrosis and cell proliferation). The results showed that follicular normality rates were lower in Pi-7 (78%) vs. control (90%) and Pi-15 (86%), similar in Ne-7 (92%) and superior in Ne-15 (97%) compared to the control, with the effect of the region Ne (94%) superior (P < 0.05) to Pi (82%). Stromal density reduced in both regions vs. control but was similar within 15 days. Fragments from both regions showed higher fibronectin labeling and deposition of type I and lower type III collagen fibers (P < 0.05) vs. control. Proliferation rates in Ne-7 were higher (P < 0.05) than in control, and Pi-15 was higher (P < 0.05) than Ne-15. In conclusion, the pinna may be a region with greater potential than the neck after a 15-day autotransplantation of canine ovarian tissue. [ABSTRACT FROM AUTHOR]

Background and purpose: Renal cell carcinoma (RCC) is a heterogeneous group of cancers. The collagen fiber content in the tumor microenvironment of renal cancer has an important role in tumor progression and prognosis. A radiomics model was developed from dual-energy CT iodine maps to assess collagen fiber content in the tumor microenvironment of ccRCC. Methods: A total of 87 patients with ccRCC admitted to our hospital were included in this retrospective study. Among them, 59 cases contained large amounts of collagen fibers and 28 cases contained a small amount of collagen fibers. We established a radiomics model using preoperative dual-energy CT scan Iodine map (IV) imaging to distinguish patients with multiple collagen fibers from those with few collagen fibers in the tumor microenvironment of ccRCC. We extracted features from dual-energy CT Iodine map images to evaluate the effects of six classifiers, namely k-nearest neighbor (KNN), support vector machine (SVM), extreme gradient boosting (XGBoost), random forest (RF), logistic regression (LR), and decision tree (DT). The effects of the models built based on the dynamic and venous phases are also compared. Model performance was evaluated using quintuple cross-validation and area under the receiver operating characteristic curve (AUC). In addition, a clinical model was developed to assess the clinical factors affecting collagen fiber content. Results: Compared to KNN, SVM, and LR classifiers, RF, DT, and XGBoost classifiers trained with higher AUC values, with training sets of 0.997, 1.0, and 1.0, respectively. In the validation set, the highest AUC was found in the SVM classifier with a size of 0.722. In the comparative test of the active and intravenous phase models, the SVM classifier had the best effect with its validation set AUC of 0.698 and 0.741. In addition, there was a statistically significant effect of patient age and maximum tumor diameter on the collagen fiber content in the tumor microenvironment of kidney cancer. Conclusion: Radionics features based on preoperative dual-energy CT IV can be used to predict the amount of collagen fibers in the tumor microenvironment of renal cancer. This study better informs clinical prognosis and patient management. Iodograms may add additional value to dual-energy CTs. [ABSTRACT FROM AUTHOR]

Abstract Biomass-based membranes have attracted increasing attentions due to their cheap and sustainable advantages. In this work, a novel thin-film composite (TFC) nanofiltration (NF) membrane was fabricated through a facial interfacial polymerization (IP) process by initiate the crosslinking reaction between collagen fibers (CFs) and tannic acid (TA). The increased TA concentrations endowed the TFC membrane with a higher crosslinking degree, a thicker active layer and a rougher top surface. At optimized condition with 0.60 mg TA decoration, the TFC-3 membrane exhibited a high water permeability of 23.49 L m−2 h−1 bar−1 with high rejections above 98.0% for congo red, reactive blue 19, coomassie blue G-250, and methyl blue. Furthermore, the membrane preserved remarkable salt retentions (93.3% for Na2SO4, 83.4% for MgSO4, 36.2% for MgCl2, and 26.4% for NaCl) and satisfying operation stability. This facial fabrication method offered a new insight to employ biomass for molecular precise separation. Graphical abstract

Background. Cold injury is one of the most significant problems for the northern regions of the Russian Federation. Frostbite is defined as a complex of changes caused by the action of low temperatures, which lead to morphological changes in damaged tissue structures. As a result, the skin with underlying tissues and the intercellular matrix, the components of which are collagen fibers, are damaged, which eventually leads to remodeling and a protracted course of the wound process. Morphometric studies in combination with quantitative analysis of microphotographs (histological specimens) using GIS technologies make it possible to distinguish altered collagen fibers under the influence of low temperatures from relatively healthy tissues. The aim of the study. To assess the possibility of using computer analysis of microphotographs in a complex of morphometric studies of collagen fibers in local cold injury. Materials and methods. The study included 84 patients with III and IV degree frostbite of the lower extremities. Morphological study of tissues and microphotography were performed using Leica DM2500 microscope (Leica, Germany). The thickness of collagen fibers was measured based on visual measurements of characteristic areas of the microphotograph. Computer analysis of tissue microphotographs of the zone of cryoinjury was performed using the ArcINFO software (Esri, USA). Statistical processing of the study results was carried out using the SPSS Statistics software package (IBM Corp., USA). Graphs and diagrams were constructed using MS Office Excel (Microsoft Corp., USA). Results. With frostbite, severe tissue damage occurs, accompanied by the destructive processes of the extracellular matrix components. Low temperatures contribute to changes in the width and orientation of collagen fibers in the damaged area. In this regard, a change in the texture of the histological specimen image leads to achange in the numerical characteristics of the standard deviation of the curvature coefficient in the studied area of the microphotograph. Thus, in the late reactive period, the described complex of morphometric studies makes it possible to classify particular microphotograph as having pathological signs or as a sample of healthy tissue.

Abstract Background It is well established that nanotopography and wettability of implant surfaces contribute to osseointegration and long-term implant success. However, the effects of a hydrogenated surface with nanotubular and superhydrophilic properties on peri-implant soft tissue remain unclear. This study was designed to study the impact of a modified abutment surface on early soft tissue integration compared with a machined surface. Methods Thirty-six implants were placed at the bone level in the bilateral mandible of six beagles, followed by healing abutments belonging to the standard machined Ti-6Al-4V alloy abutments (TC4-M), anodized abutments with nanotubes (TC4-Nano), and hydrogenated abutments (TC4-H/Nano) groups, which were randomly screwed to the implants. After two and four weeks of wound healing, the animals were euthanized for histological evaluation. Results A superhydrophilic nanotubular surface developed on the hydrogenated abutment. Histological and histometric analyses revealed similar peri-implant soft tissue healing and dimensions for the three types of abutments at two and four weeks. Connective tissue (CT) length was longer around TC4-H/Nano abutments compared with standard abutments; however, the differences were not statistically significant. Moreover, collagen fibers in the TC4-H/Nano group extended and were attached perpendicularly to the superhydrophilic surface. Conclusions Our results revealed that the soft tissue interface adjacent to the hydrogenated abutment is comparable to that of the machined abutment. A tendency of increased CT length and perpendicular collagen fibers was observed around the modified abutment. This study suggests that nanotubular/superhydrophilic surfaces could be a promising modification to enhance soft tissue sealing. However, comprehensive studies should be conducted to evaluate the peri-implant soft tissue around the modified abutment immunohistochemically, histopathologically, and clinically.

The article presents the results of ultrastructural research on fibroblastic sarcoid, which is one of the most aggressive types of sarcoid in horses. A retrospective study on the prevalence of sarcoids in horses in Ukraine’s western regions was conducted in 2019–2023. It was found that during the period of 2022–2023, the number of horses with sarcoids increased sharply by 15.6% compared to the period 2020–2021. This was associated with the mass movement of animals from eastern regions due to the onset of the war in Ukraine. The fibroblastic type of sarcoid was predominantly localized in the abdominal wall and groin area. To study the ultrastructure of sarcoids, they were surgically removed by excising undamaged skin portions under general anesthesia, adhering to all requirements of the European Convention for the Protection of Animals used for Experimental and Other Scientific Purposes. Electronograms revealed that the tumour formation mainly consisted of fibroblasts of varying differentiation degrees: significant number of vesicles, markedly expanded endoplasmic reticulum cisterns, and irregularly shaped nuclei with numerous invaginations. Open nuclear pores were observed in most nuclei. Active formation of a large number of capillaries was noted between the collagen matrix, fibroblasts, and fibrocytes, indicated by the increased number of endotheliocytes with pseudopodia on the cytoplasm’s marginal part and the basal surface. This suggests their embryonic type. Endotheliocytes contained large round nuclei and a significant number of mitochondria in the cytoplasm. There were both bright and dark endotheliocytes in the blood capillaries’ venous section. The cytoplasm of bright endotheliocytes contained myofilaments, individual mitochondria, free ribosomes, peroxisomes, and vesicles of various sizes. The plasmalemma formed small pseudopodia. The capillary lumen showed moderate electron density. Additionally, high platelet activity was observed, manifested by cell adhesion to the marginal part of the endotheliocyte cytoplasm. It should be noted that most capillaries were of the venous type, as indicated by the endotheliocytes’ height, the presence of an increased number of mitochondria and vesicles. The entire cellular pool was localized among the massive framework consisting of collagen fibers. Elastic fibers could not be detected in the fibrillar component.

The digestive organs are highly sensitive to the influence of orbital flight factors and can limit the professional activities of crew members aboard the International Space Station. Connective tissue, as a system-forming matrix of the integrative-buffer metabolic environment, is of particular relevance in space biomedicine, ensuring the functioning of internal organs under an altered gravitational stimulus. However, the adaptive mechanisms of the fibrous extracellular matrix of the gastric and intestinal connective tissue have not been fully investigated under prolonged microgravity weightlessness. Using histochemical techniques, we experimentally studied the state of collagen fibers in the specific tissue microenvironment of the gastric and intestinal membranes in C57BL/6 N mice after a 30-day space flight, subsequent 7-day ground readaptation, and in animals of the relevant control groups. The 30-day stay of laboratory animals aboard the Bion-M 1 biosatellite resulted in a reduction in the fibrous extracellular matrix of connective tissue in the studied digestive organs, excepting the gastric lamina propria. Increased fibrillogenesis was revealed in the gastrointestinal mucous membranes of animals 7 days after biosatellite landing compared with the parameters of animals in the space flight group. During the experiment with ground simulated orbital flight conditions, changes in collagen fibers were not significant compared to the vivarium control group. Thus, the results obtained evidence gravisensitivity of the fibrous extracellular matrix of the intraorgan connective tissue. This fact also highlights the necessity to further improve gastrointestinal tract-related preventive measures for astronauts during orbital flight.

Biomass-based membranes have attracted increasing attentions due to their cheap and sustainable advantages. In this work, a novel thin-film composite (TFC) nanofiltration (NF) membrane was fabricated through a facial interfacial polymerization (IP) process by initiate the crosslinking reaction between collagen fibers (CFs) and tannic acid (TA). The increased TA concentrations endowed the TFC membrane with a higher crosslinking degree, a thicker active layer and a rougher top surface. At optimized condition with 0.60 mg TA decoration, the TFC-3 membrane exhibited a high water permeability of 23.49 L m−2 h−1 bar−1 with high rejections above 98.0% for congo red, reactive blue 19, coomassie blue G-250, and methyl blue. Furthermore, the membrane preserved remarkable salt retentions (93.3% for Na2SO4, 83.4% for MgSO4, 36.2% for MgCl2, and 26.4% for NaCl) and satisfying operation stability. This facial fabrication method offered a new insight to employ biomass for molecular precise separation. [ABSTRACT FROM AUTHOR]

Tendons are collagen-based connective tissues where the composition, structure and mechanics respond and adapt to the local mechanical environment. Adaptation to prolonged inactivity can result in stiffer tendons that are more prone to injury. However, the complex relation between reduced loading, structure, and mechanical performance is still not fully understood. This study combines mechanical testing with high-resolution synchrotron X-ray imaging, scattering techniques and histology to elucidate how reduced loading affects the structural properties and mechanical response of rat Achilles tendons on multiple length scales. The results show that reduced in vivo loading leads to more crimped and less organized fibers and this structural inhomogeneity could be the reason for the altered mechanical response. Unloading also seems to change the fibril response, possibly by altering the strain partitioning between hierarchical levels, and to reduce cell density. This study elucidates the relation between in vivo loading, the Achilles tendon nano-, meso‑structure and mechanical response. The results provide fundamental insights into the mechanoregulatory mechanisms guiding the intricate biomechanics, tissue structural organization, and performance of complex collagen-based tissues. Achilles tendon properties allow a dynamic interaction between muscles and tendon and influence force transmission during locomotion. Lack of physiological loading can have dramatic effects on tendon structure and mechanical properties. We have combined the use of cutting-edge high-resolution synchrotron techniques with mechanical testing to show how reduced loading affects the tendon on multiple hierarchical levels (from nanoscale up to whole organ) clarifying the relation between structural changes and mechanical performance. Our findings set the first step to address a significant healthcare challenge, such as the design of tailored rehabilitations that take into consideration structural changes after tendon immobilization. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: It is well established that nanotopography and wettability of implant surfaces contribute to osseointegration and long-term implant success. However, the effects of a hydrogenated surface with nanotubular and superhydrophilic properties on peri-implant soft tissue remain unclear. This study was designed to study the impact of a modified abutment surface on early soft tissue integration compared with a machined surface. Methods: Thirty-six implants were placed at the bone level in the bilateral mandible of six beagles, followed by healing abutments belonging to the standard machined Ti-6Al-4V alloy abutments (TC4-M), anodized abutments with nanotubes (TC4-Nano), and hydrogenated abutments (TC4-H/Nano) groups, which were randomly screwed to the implants. After two and four weeks of wound healing, the animals were euthanized for histological evaluation. Results: A superhydrophilic nanotubular surface developed on the hydrogenated abutment. Histological and histometric analyses revealed similar peri-implant soft tissue healing and dimensions for the three types of abutments at two and four weeks. Connective tissue (CT) length was longer around TC4-H/Nano abutments compared with standard abutments; however, the differences were not statistically significant. Moreover, collagen fibers in the TC4-H/Nano group extended and were attached perpendicularly to the superhydrophilic surface. Conclusions: Our results revealed that the soft tissue interface adjacent to the hydrogenated abutment is comparable to that of the machined abutment. A tendency of increased CT length and perpendicular collagen fibers was observed around the modified abutment. This study suggests that nanotubular/superhydrophilic surfaces could be a promising modification to enhance soft tissue sealing. However, comprehensive studies should be conducted to evaluate the peri-implant soft tissue around the modified abutment immunohistochemically, histopathologically, and clinically. [ABSTRACT FROM AUTHOR]

Collagen provides tissue strength and structural integrity. Quantification of the orientated dispersion of collagen fibers is an important factor when studying the mechanical properties of the cervix. In this study, for the first time, a new method for rapid characterization of the collagen fiber orientations of the cervix using linearly polarized light colposcopy is presented. A total of 24 colposcopic images were captured using a cross-polarized imaging system with white LED light sources. In the preprocessing stage, the Red channel of the RGB image was chosen, which contains no information of the blood vessels because of the low-absorption of blood cells in the red region. OrientationJ, which is an ImageJ plug-in, was used to estimate the local orientation of the collagen fibers. The result shows that in the nonpregnant cervix, the middle zone (Zone 2) has circumferentially aligned collagen fibers while the inner zone (Zone 1) has randomly arranged. The collagen fiber dispersion in Zone 2 is much smaller than that in Zone 1 at all four quadrants region (anterior, posterior, left, and right quadrant). This new analysis technique could potentially combine with diagnostic tools to provide a quantitative platform of collagen fibers in the clinic. [ABSTRACT FROM AUTHOR]

The design of the implant prosthesis–abutment complex appears crucial for shaping healthy and stable peri-implant soft tissues. The aim of the present animal study was to compare two implants with different healing abutment geometries: a concave design (TEST) and a straight one (CTRL). Transmission electron microscopy (TEM) was used to quantify the three-dimensional topography and morphological properties of collagen at nanoscale resolution. 2 swine were included in the experiment and 6 implants per animal were randomly placed in the left or right hemimandible in either the physiologically mature bone present between the lower canine and first premolar or in the mandibular premolar area, within tooth extraction sites. Each CTRL implant was positioned across from its respective TEST implant on the other side of the jaw. After 12 weeks of healing, 8 specimens (4 CTRL and 4 TEST) were retrieved and prepared for histological and TEM analysis. The results showed a significantly higher percentage of area covered by collagen bundles and average bundle size in TEST implants, as well as a significant decrease in the number of longitudinally oriented bundles with respect to CTRL implants, which is potentially due to the larger size of TEST bundles. These data suggest that a concave transmucosal abutment design serves as a scaffold, favoring the deposition and growth of a well-organized peri-implant collagen structure over the implant platform in the early healing phase, also promoting the convergence of collagen fibers toward the abutment collar. [ABSTRACT FROM AUTHOR]

Objectives: By comparing with the control group, we evaluated the usefulness of contrast‐enhanced ultrasound (CEUS) combined with elastography for the assessment of muscle invasion by bladder cancer (MIBC) in a Sprague–Dawley (SD) rat model. Methods: In the experimental group, 40 SD rats developed in situ bladder cancer (BLCA) in response to N‐methyl‐N‐nitrosourea treatment, whereas 40 SD rats were included in the control group for comparison. We compared PI, Emean, microvessel density (MVD), and collagen fiber content (CFC) between the two groups. In the experimental group, Bland–Altman test was used to assess the relationships between various parameters. The largest Youden value was used as the cut‐off point, and binomial logistic regression analysis was performed to analyze the PI and Emean. Receiver operating characteristic (ROC) curve analysis was performed to determine the diagnostic power of parameters, individually and in combination. Results: The PI, Emean, MVD, and CFC were significantly lower in the control group than in the experimental group (P <.05). The PI, Emean, MVD, and CFC were significantly higher for MIBC than for non‐muscle‐invasive bladder cancer (P <.05). There were significant correlations between PI and MVD, and between Emean and CFC. The diagnostic efficiency analysis showed PI had the highest sensitivity, CFC had the highest specificity, and PI + Emean had the highest diagnostic efficacy. Conclusion: CEUS and elastography can distinguish lesions from normal tissue. PI, MVD, Emean, and CFC were useful for the detection of BLCA myometrial invasion. The comprehensive utilization of PI and Emean improved diagnostic accuracy and have clinical application. [ABSTRACT FROM AUTHOR]

Doxorubicin is associated with cardiotoxicity, and physical exercise seeks to minimize the toxic effects of doxorubicin through physiological cardiac remodeling, as well as the reduction of oxidative stress, evidenced by previous studies. This study aimed to analyze whether running training before treatment with doxorubicin influences tolerance to physical exertion and cardiotoxicity. Thirty-nine male Wistar rats, aged 90 days and weighing between 250 and 300 g, were divided into 4 groups: Control (C), Doxorubicin (D), Trained (T), and Trained + Doxorubicin (TD). Animals in groups T and DT were submitted to treadmill running for 3 weeks, 5 times a week at 18 m/min for 20–30 min before treatment with doxorubicin. Animals in groups D and DT received intraperitoneal injections of doxorubicin hydrochloride three times a week for two weeks, reaching a total cumulative dose of 7.50 mg/kg. Our results show an increase in total collagen fibers in the D group (p = 0.01), but no increase in the TD group, in addition to the attenuation of the number of cardiac mast cells in the animals in the TD group (p = 0.05). The animals in the TD group showed maintenance of tolerance to exertion compared to group D. Therefore, running training attenuated the cardiac damage caused by the treatment with doxorubicin, in addition to maintaining the tolerance to exertion in the rats. [ABSTRACT FROM AUTHOR]

Atrioventricular heart valves (AHVs) regulate the unidirectional flow of blood through the heart by opening and closing of the leaflets, which are supported in their functions by the chordae tendineae (CT). The leaflets and CT are primarily composed of collagen fibers that act as the load-bearing component of the tissue microstructures. At the CT-leaflet insertion, the collagen fiber architecture is complex, and has been of increasing focus in the previous literature. However, these previous studies have not been able to quantify the load-dependent changes in the tissues collagen fiber orientations and alignments. In the present study, we address this gap in knowledge by quantifying the changes in the collagen fiber architecture of the mitral and tricuspid valves strut CT-leaflet insertions in response to the applied loads by using a unique approach, which combines polarized spatial frequency domain imaging with uniaxial mechanical testing. Additionally, we characterized these microstructural changes across the same specimen without the need for tissue fixatives. We observed increases in the collagen fiber alignments in the CT-leaflet insertion with increased loading, as described through the degree of optical anisotropy. Furthermore, we used a leaflet-CT-papillary muscle entity method during uniaxial testing to quantify the chordae tendineae mechanics, including the derivation of the Ogden-type constitutive modeling parameters. The results from this study provide a valuable insight into the load-dependent behaviors of the strut CT-leaflet insertion, offering a research avenue to better understand the relationship between tissue mechanics and the microstructure, which will contribute to a deeper understanding of AHV biomechanics.

Collagen provides tissue strength and structural integrity. Quantification of the orientated dispersion of collagen fibers is an important factor when studying the mechanical properties of the cervix. In this study, for the first time, a new method for rapid characterization of the collagen fiber orientations of the cervix using linearly polarized light colposcopy is presented. A total of 24 colposcopic images were captured using a cross-polarized imaging system with white LED light sources. In the preprocessing stage, the Red channel of the RGB image was chosen, which contains no information of the blood vessels because of the low-absorption of blood cells in the red region. OrientationJ, which is an ImageJ plug-in, was used to estimate the local orientation of the collagen fibers. The result shows that in the nonpregnant cervix, the middle zone (Zone 2) has circumferentially aligned collagen fibers while the inner zone (Zone 1) has randomly arranged. The collagen fiber dispersion in Zone 2 is much smaller than that in Zone 1 at all four quadrants region (anterior, posterior, left, and right quadrant). This new analysis technique could potentially combine with diagnostic tools to provide a quantitative platform of collagen fibers in the clinic.

Background: Liver fibrosis is a global health problem, and studying its development provides important information to address its treatment. Here, we characterized the effects of an adenosine compound (IFC-305) on preventing fibrosis and liver inflammation. Methods: We studied the impact of IFC-305 on a carbon tetrachloride-induced liver fibrosis model in Wistar male rats at 4, 6, and 8 weeks. The effects were characterized by liver tissue histology, macrophages identification by flow cytometry with CD163+/CD11b/c+ antibodies, hepatic and plasmatic cytokine levels employing MILLIPLEX MAP and ELISA, Col1a1 and Il6 gene expression by RTqPCR, lipoperoxidation by TBARS reaction, and reactive oxygen species using 2'−7'dichlorofluorescin diacetate. Results: CCl4-induced liver fibrosis and inflammation were significantly reduced in rats treated with IFC-305 at 6 and 8 weeks. In addition, we observed diminished expression of Col1a1; a decrease in the inflammatory cytokines IL-1β, IL-6, MCP-1, TNF-α, and IL-4 a; reduction in inflammatory macrophages; inhibition of lipoperoxidation; and ROS production in Kupffer cells. Conclusion: This study showed that IFC-305 can inhibit liver fibrosis establishment by regulating the immune response during CCl4-induced damage. The immunomodulatory action of IFC-305 supports its use as a potential therapeutic strategy for preventing liver fibrosis.

The article presents the results of ultrastructural research on fibroblastic sarcoid, which is one of the most aggressive types of sarcoid in horses. A retrospective study on the prevalence of sarcoids in horses in Ukraine’s western regions was conducted in 2019–2023. It was found that during the period of 2022–2023, the number of horses with sarcoids increased sharply by 15.6% compared to the period 2020–2021. This was associated with the mass movement of animals from eastern regions due to the onset of the war in Ukraine. The fibroblastic type of sarcoid was predominantly localized in the abdominal wall and groin area. To study the ultrastructure of sarcoids, they were surgically removed by excising undamaged skin portions under general anesthesia, adhering to all requirements of the European Convention for the Protection of Animals used for Experimental and Other Scientific Purposes. Electronograms revealed that the tumour formation mainly consisted of fibroblasts of varying differentiation degrees: significant number of vesicles, markedly expanded endoplasmic reticulum cisterns, and irregularly shaped nuclei with numerous invaginations. Open nuclear pores were observed in most nuclei. Active formation of a large number of capillaries was noted between the collagen matrix, fibroblasts, and fibrocytes, indicated by the increased number of endotheliocytes with pseudopodia on the cytoplasm’s marginal part and the basal surface. This suggests their embryonic type. Endotheliocytes contained large round nuclei and a significant number of mitochondria in the cytoplasm. There were both bright and dark endotheliocytes in the blood capillaries’ venous section. The cytoplasm of bright endotheliocytes contained myofilaments, individual mitochondria, free ribosomes, peroxisomes, and vesicles of various sizes. The plasmalemma formed small pseudopodia. The capillary lumen showed moderate electron density. Additionally, high platelet activity was observed, manifested by cell adhesion to the marginal part of the endotheliocyte cytoplasm. It should be noted that most capillaries were of the venous type, as indicated by the endotheliocytes’ height, the presence of an increased number of mitochondria and vesicles. The entire cellular pool was localized among the massive framework consisting of collagen fibers. Elastic fibers could not be detected in the fibrillar component. [ABSTRACT FROM AUTHOR]

Introduction: Tartrazine is a broadly used food additive. It can induce several adverse effects on different body organs. Omega-3 fatty acids have a documented antioxidant, anti-apoptotic and anti-inflammatory effects. Aim of the work: To study the induced histological changes by tartrazine in the parotid gland and to investigate the protective action of omega-3-fatty acids against these changes. Material and Methods: Twenty-one adult male albino rats were divided into 3 groups; Group I (control group), Group II (tartrazine treated group) received tartrazine daily at a dose of 320 mg/kg body weight orally and Group III (tartrazine and omega-3 treated group) received omega3 daily at a dose of 300 mg/kg body weight orally in addition to tartrazine in the same dose in group II. The treatment continued for four weeks. Parotid gland specimens were processed for light microscopic examination using Hematoxylin and Eosin, Sirius red stains and caspase-3 immunostaining in addition to electron microscopic examination. Results: Parotid acini in tartrazine-treated group showed a histological deterioration in the form of darkly stained nuclei and cytoplasmic vacuolations. Statistically, area % of both collagen fibers staining and caspase-3 immunostaining increased significantly in comparison to the control group. Ultra-structurally, irregular nuclei, electron-lucent granules dominance and dilated rough endoplasmic reticulum were detected in the acinar cells of tartrazine-treated group in addition to degenerative changes in ductal epithelium. Treatment with omega-3 improved the structure of the parotid gland as detected by both histological and morphometric studies. Conclusion Omega-3 treatment ameliorated the structural effects of tartrazine on the parotid gland. [ABSTRACT FROM AUTHOR]

In this paper, a structural analysis of the rarely encountered hydrozoan medusa Limnocnida indica Annandale is discussed. This diploblastic, radially symmetrical organism has a body plan typical of hydrozoan medusae. In this study more emphasis was given to observation of the supporting components of its anatomical structures. Detailed observation on the distribution of supportive components including chitin, collagen, and noncellular fibers within the tissue organization has been carried out with the application of different types of staining methods. The neuromuscular arrangement at the rim of the umbrella and basal part of the gastrovascular cavity and the distribution of the neurons in the sub epithelial region of ectoderm have been analyzed both by staining and by scanning electron microscopy studies. Supporting blocks of chitin at the base of tentacles, along with statocysts, and ring-like deposition of chitin and collagen on the tentacles are documented. Distribution of collagen around radial canals in the mesoglea was found to be unique to this species. The mesoglea seems to be a storehouse for the macromolecules chitin and collagen. [ABSTRACT FROM AUTHOR]

Simple Summary: Sea cucumbers are very sensitive to the influence of environmental factors, and will vomit their intestines and undergo tissue degradation under certain stimuli. In order to determine the effect of endogenous enzymes in the sea cucumber intestine on the body wall during body wall softening, intestine extracts and crude collagen fibers were prepared, respectively. The endogenous enzymes belonging to serine proteases were identified by gelatin zymography. The rheological property results showed that the addition of sea cucumber intestinal extracts reduced the viscosity of crude collagen fibers from 32.7 Pa·s to 5.3 Pa·s. The serine protease inhibitor phenylmethylsulfonyl fluoride inhibited the activity of intestinal extracts, and maintained the viscoelasticity of crude collagen fibers. In this paper, endogenous enzymes in sea cucumber intestinal extracts were identified as serine endopeptidases, which caused softening of the body wall. Sea cucumbers Apostichopus japonicus will vomit their intestines during certain stimulations, and the collagen of the body wall will then be degraded. To define the effect of the sea cucumber intestine extracts on the body wall, the intestinal extracts and crude collagen fibers (CCF) of sea cucumber A. japonicus were prepared. According to the gelatin zymography, the type of endogenous enzymes in intestinal extracts were mainly serine endopeptidases with optimal activities at pH 9.0 and 40 °C. According to the rheology results, the viscosity of 3% CCF decreased from 32.7 Pa·s to 5.3 Pa·s by adding intestine extracts. The serine protease inhibitor phenylmethanesulfonyl fluoride inhibited the activity of intestinal extracts and increased the viscosity of collagen fibers to 25.7 Pa·s. The results proved that serine protease in the intestinal extracts participated in the process of body wall softening in sea cucumbers. [ABSTRACT FROM AUTHOR]

Cartilage cracks disrupt tissue mechanics, alter cell mechanobiology, and often trigger tissue degeneration. Yet, some tissue cracks heal spontaneously. A primary factor determining the fate of tissue cracks is the compression-induced mechanics, specifically whether a crack opens or closes when loaded. Crack deformation is thought to be affected by tissue structure, which can be probed by quantitative polarized light microscopy (PLM). It is unclear how the PLM measures are related to deformed crack morphology. Here, we investigated the relationship between PLM-derived cartilage structure and mechanical behavior of tissue cracks by testing if PLM-derived structural measures correlated with crack morphology in mechanically indented cartilages. Methods: Knee joint cartilages harvested from mature and immature animals were used for their distinct collagenous fibrous structure and composition. The cartilages were cut through thickness, indented over the cracked region, and processed histologically. Sample-specific birefringence was quantified as two-dimensional (2D) maps of azimuth and retardance, two measures related to local orientation and degree of alignment of the collagen fibers, respectively. The shape of mechanically indented tissue cracks, measured as depth-dependent crack opening, were compared with azimuth, retardance, or "PLM index," a new parameter derived by combining azimuth and retardance. Results: Of the three parameters, only the PLM index consistently correlated with the crack shape in immature and mature tissues. Conclusion: In conclusion, we identified the relative roles of azimuth and retardance on the deformation of tissue cracks, with azimuth playing the dominant role. The applicability of the PLM index should be tested in future studies using naturally-occurring tissue cracks. [ABSTRACT FROM AUTHOR]

IntroductionThe orientation of collagen fibers in native tissues plays an important role in cell signaling and mediates the progression of tumor cells in breast cancer by a contact guidance mechanism. Understanding how migration of epithelial cells is directed by the alignment of collagen fibers requires in vitro assays with standardized orientations of collagen fibers.MethodsTo address this issue, we produced micro-stripes with aligned collagen fibers using an easy-to-use and versatile approach based on the aspiration of a collagen solution within a microchannel. Glass coverslips were functionalized with a (3-aminopropyl)triethoxysilane/glutaraldehyde linkage to covalently anchor micro-stripes of aligned collagen fibers, whereas microchannels were functionalized with a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) nonionic triblock polymer to prevent adhesion of the collagen micro-stripes.ResultsUsing this strategy, microchannels can be peeled off to expose micro-stripes of aligned collagen fibers without affecting their mechanical integrity. We used time-lapse confocal reflection microscopy to characterize the polymerization kinetics of collagen networks for different concentrations and the orientation of collagen fibers as a function of the microchannel width. Our results indicate a non-linear concentration dependence of the area of fluorescence, suggesting that the architecture of collagen networks is sensitive to small changes in concentration. We show the possibility to influence the collagen fibril coverage by adjusting the concentration of the collagen solution.ConclusionWe applied this novel approach to study the migration of epithelial cells, demonstrating that collagen micro-stripes with aligned fibers represent a valuable in-vitro assay for studying cell contact guidance mechanisms.

Background: Development of the human fetal stomach starts at the 4th week of intrauterine life. The knowledge of histogenesis of the musculature of the stomach is important for understanding, diagnosis, and treatment of gastric adenomyoma, congenital anomalies like congenital hypertrophic pyloric stenosis, and abnormalities in the development of the enteric nervous system. The aim of this study was to find out the histogenesis of the submucosa (SM), muscularis mucosa (MM), and muscularis externa (ME) in the human fetal stomach. Methodology: Sixty-three freshly aborted fetuses which were free from any gross abnormality were collected from the obstetrics and gynecology department and studied for 2 years. The fetuses were dissected, the stomach was removed, and the tissue was processed for a histological study. Staining was done by hematoxylin and eosin, Masson's trichrome, and Van Gieson's stain. Slides were studied under Zeiss branded light microscope using ×10 and ×40 objectives. Results: MM was discontinuous initially and became well defined by 21 weeks in the fundus and body and by the 23rd week in the pyloric region. The density of collagen fibers increased gradually in SM and was seen in bundles from the 23rd week onward. The thickness of SM was more than ME till 22 weeks, and after 27 weeks, it was less than that of ME. In the fundus and body of the stomach, till 18 weeks, ME consisted of two layers, with the inner oblique layer being thicker than the circular layer. The circular layer thickened gradually, and the longitudinal layer appeared by the 25th week. In the pyloric region, initially, there was only a circular layer. The oblique and longitudinal muscle layers appeared at 17–18 weeks and 25th week, respectively. The thickness of the circular layer was found to be more than that of the body from the 21st week onward and became much thicker at around the 27th week. The histological feature of MM, ME, and SM of the stomach resembled an adult pattern by the 28th week of gestational age. Conclusion: The findings of the present study about the time of appearance and further development of MM and ME and the thickness and formation of SM of the human fetal stomach are quite comprehensive. These findings are expected to aid in the knowledge of histogenesis of the stomach in the human fetuses and help in the diagnosis and treatment of various congenital anomalies and clinical conditions involving gastric connective tissue and musculature.

An arterial vessel has three layers, namely, the intima, the media and the adventitia. Each of these layers is modeled to have two families of strain-stiffening collagen fibers that are transversely helical. In an unloaded configuration, these fibers are coiled up. In the case of a pressurized lumen, these fibers stretch and start to resist further outward expansion. As the fibers elongate, they stiffen, affecting the mechanical response. Having a mathematical model of vessel expansion is crucial in cardiovascular applications such as predicting stenosis and simulating hemodynamics. Thus, to study the mechanics of the vessel wall under loading, it is important to calculate the fiber configurations in the unloaded configuration. The aim of this paper is to introduce a new technique of using conformal maps to numerically calculate the fiber field in a general arterial cross-section. The technique relies on finding a rational approximation of the conformal map. First, points on the physical cross section are mapped to points on a reference annulus using a rational approximation of the forward conformal map. Next, we find the angular unit vectors at the mapped points, and finally a rational approximation of the inverse conformal map is used to map the angular unit vectors back to vectors on the physical cross section. We have used MATLAB software packages to achieve these goals.

Background: The recent increase in hostilities throughout the globe is one of the main factors that damage both the skin and peripheral nerves (PN), mainly of the upper and lower extremities. The duration of treatment of the injured limb and the rate of recovery of its functions are directly related to the structural integrity of the connective tissue (CT) sheath apparatus of the PN, which further actualizes the study of its micromorphological components. The structural integrity of the peripheral nerve includes not only the preservation of its conductive component but also the membranes surrounding it, providing complete morphofunctional unity. Thus, the study of the features of their tissue organization, vascularization and innervation, with the obligatory comparison of data with homologous tissue of different topography and possible extrapolation of data, determined the purpose of this work. The aim of this study was to analyze the dynamics of changes in the fibrous components of the paraneurium and dermis in onto- and phylogenesis under the influence of various factors and to compare the data obtained for their further extrapolation. Methods and Results: The study was conducted on mature male Wistar rats under standard vivarium conditions. The material for the study was the CT sheaths of the PN of the extremities and skin areas, 1x1 cm in size, to the depth of the subcutaneous fascia of animals. The cadaver material was taken on Days 1, 3, 7, 10, and 28 of ontogeny. The resulting biomaterial was fixed in a 10% buffered neutral formalin solution and embedded in paraffin, according to the standard method. Microtomized, the resulting histological sections were stained with hematoxylin and eosin, according to the method of Mallory and Van Gieson. A comprehensive morphological study was performed using light and electron microscopy. The study revealed the presence of two stages in the ontogeny of the CT, forming the dermis of the skin and paraneural CT structures of PN. In the first stage, structural elements are formed, considering the topography of the CT; in the second, they are differentiated, leading to a qualitative-quantitative transformation due to the appearance of a number of additional functions, an active period of body growth, and taking into account the action of various environmental factors. At earlier stages of ontogenesis, thin, flattened fibrous structures without a clear organization are observed in the field of view in the dermis of the skin. In the paraneurium, the components that form it are not sufficiently expressed. At later periods, the shape and architectonics of the fibrous component change, structurization and an increase in the thickness of the fibers occur and pronounced heterogeneity of the cellular component is observed.

Sarcoid is one of the most common skin tumours, which is diagnosed in various breeds of horses at any age regardless of the animal’s sex. Such fibroblastic neoplasm manifests itself in several clinical ways with its specific morphological features. As a rule, it metastasizes rarely but can be locally invasive. The disease’setiology is multifactorial and includes the confirmed role of the bovine papillomavirus and genetic and environmental factors. The article introduces the results of a retrospective study of horses of the Ukrainian riding breed with a fibroblastic sarcoid type, which was localized mainly in the area of the external thoracic vein. Neoplasms were represented by two types. The first one included broad base neoplasms without a pronounced pedicle but with signs of hyperkeratosis. Massive rounded dense formations with an ulcerated surface refer to the second type. To verify the studied types of sarcoid, wide surgical excision of the lesion’svisible parts was performed, followed by the selection of fragments for the pathohistological diagnosis. Also, additional staining methods were used to detect the connective and muscle tissue (Van Gieson’s staining) and elastic fibers (Weigert’s resorcin-fuchsin staining). Microscopically, the neoplasm without a visible pedicle showed signs of hyperkeratosis and acanthosis in the peritumoral epidermal layer. Epidermis desquamation with a significant amount of oxyphilic detritus, diapedesis hemorrhages, and dilated vessels was also detected in some areas. Chaotic placement of fibroblasts and fibrocytes was noted, to a greater extent, subdermally. Anisocytosis and anisokaryosis were expressed moderately. Sarcoids, macroscopically presented in the form of massive dense formations with an ulcerated surface, were histologically characterized by the replacement of the epidermis with cellular elements, subdermal hemorrhages, and the characteristic perpendicular orientation of coarse collagen fibers towards the basement membrane. Closely spaced spindle-shaped cells with fibers forming moiré structures were visualized in the deep dermis layers. Nuclei were hyperchromic and elongated in shape, no atypical mitoses were noted. Pathohistological examination during the identification of a sarcoid type for diagnostic purposes can cause rapid growth and formation of an ulcer. The final diagnosis regarding equine sarcoid can be made based on a combination of clinical signs, histopathological examination, and molecular genetic testing with the isolation of BPV DNA.

Aim – to conduct a comparative analysis of the structure and thickness of the dura mater between men and women in the first period of adulthood and in old age. Material and methods. We analysed the results of the complex morphological study of the dura mater in 91 deceased (49 male and 42 female) aged of 22 to 32 and 75 to 88 years. The deceased were divided into two groups according to their age. Group I included 49 cases of the first period of adulthood: 26 men and 23 women who died at the age of 22 to 32. Group II consisted of 42 cases of senile age: 23 men and 19 women who died at the age of 75 to 88. The autopsy material was collected around the parietal bones, in the projection of the sagittal suture. Results. The dura mater was represented by dense unformed connective tissue. The collagen fibers in the first period of adulthood are compactly organized, have a clear direction and structure. In the old age there is a pronounced disorder of the fibers. The walls of blood vessels in senile patients are usually thickened. The dura mater thickens with age by 29.2% in men and by 28.2% in women.

Abstract The effect of hydrophobic modification on the performances of collagen fibers (CFs) was investigated by using silane coupling agents with different alkyl chains as hydrophobic modifiers. It was found silane could be easily grafted onto CF surface through covalent bonds under 5% water content. This modification led to the transformation of surface wettability of CF from hydrophilic to hydrophobic. Interestingly, the change of surface wettability resulted in substantial improvement of the modified CF properties, presenting well dispersity of collagen fibers, higher thermal stability and enhanced mechanical properties in comparison with natural CF. The degree of improvement mainly depended on the length of alkyl chain in silane. Longer alkyl chain produced strong hydrophobicity and subsequently more superior performances of the modified CF. When the length of alkyl chain increased to 18 carbon atoms, the modified CF possessed durable superhydrophobicity even exposed to aqueous solutions of different pH, UV, and organic solvents, and had excellent thermal and mechanical properties like leather fibers. In general, this work clearly revealed that the properties of CF are closely and positively related to the hydrophobicity, which is suggestive in developing new leather making technology. Graphical Abstract

Researchers are looking for ways to protect the bones of people with diabetes and high blood pressure. The focus of this research was on hepatocyte growth factor (HGF), which is a natural molecule in the body that regulates the growth process. Also, this molecule plays a role in bone reproduction, changing its shape and creating a balance between osteoblast and osteoclast. But what was unknown about this molecule until now is that the HGF molecule also affects the chemical structure of bones. In order to investigate these effects, HGF molecules were injected into diabetic rats with high blood pressure and then, using a spectroscopic technique, they analyzed the chemical structure of the bones of these rats. As a result, it was found that soluble phosphate in bones increases with HGF intake. This important change shows that HGF molecules can stimulate the process of bone regeneration in response to diabetes, high blood pressure and drugs used to treat these diseases. In osteoporosis, the bones become porous. The microscopic structure of bones is honeycomb. Pores and houses in cancellous bone are much larger than healthy bone. In this case, the bones gradually lose their mass and density and become very sensitive and fragile. Bones are composed of collagen fibers and minerals. From birth to early 20s, bone cells grow and thicken by absorbing nutrients and minerals. Usually, the peak of bone density is at the age of 20. Bone growth and development continues until about 25 years of age and rarely slows down thereafter. After the age of 45 and with increasing age, the bone density gradually decreases and the calcium required for the body is supplied from the bones. Decrease in bone density with age is completely normal; But some factors accelerate this process. Inactivity, reduction of vitamin D in the body, suffering from certain diseases such as cancer, premature menopause, reduction of estrogen in the body and certain medical conditions such as hyperthyroidism, celiac disease, chronic kidney failure, rheumatoid arthritis, chronic liver diseases and type one diabetes are the most important are the risk factors of the disease. The use of special drugs such as steroid, hormonal, anticonvulsant and antidepressant drugs are among the most important drugs that reduce bone density. [ABSTRACT FROM AUTHOR]

The extracellular matrix (ECM) scaffolds are considered a gold standard for the engineering of appropriate grafts used in regenerative medicine for tissue repair, and decellularization of myocardial tissue is one of the most studied processes for obtaining natural ECM to date. Decellularization methods, agents used, or treatment durations can be varied to optimize cardiac tissue decellularization parameters. In this work we performed a morphological and morphometric analysis of cardiac tissue subjected to decellularization protocols based on Sodium Deoxycholate (SD) or Sodium Lauryl Sulfate (SLS) to identify factors that allow optimization of single-detergent based protocols for cardiac ECM manufacturing. For this, Wistar rat hearts (n=10) were subjected to 5 different decellularization protocols (n=2) and then histologically processed to achieve H&E or Azan trichrome stained sections for the morphological and morphometric analysis of the obtained ECM. The results of this study showed that SLS alters the spatial distribution of cardiac ECM collagen fibers, and SD can be successfully used in tailoring single-based detergent decellularization protocols by appropriately adjusting the application times of hypo/hyperosmotic shocks, which increases the lytic action of the detergent, and the washing times for the efficient elimination of cellular residues. [ABSTRACT FROM AUTHOR]

Constructing proper in vitro tumor immune microenvironment (TIME) is important for cancer immune‐therapy studies, while the selection of biomaterials is critical. As innate immune cells, macrophages can target and kill cancer cells in vivo at the early stage of tumor development. However, this targeting phenomenon has not been observed in vitro. Herein, a quasi‐3D in vitro cell culture model is constructed to mimic TIME by integrating hydrogel collagen as extracellular matrix for cells. In the collagen‐based quasi‐3D in vitro system, for the first time, it is found that macrophages can be attracted toward cancer cells along the dynamically reconstructed collagen fibers. By combining traction force microscopy and customized micro‐manipulator system, it is revealed that the collagen matrix‐transmitted tensile force signaling precisely guides the migration of macrophages toward cancer cells. The mechano‐responsiveness mechanism is related to the activation of mechanosensitive ion channels, and the induced local increase of calcium signal, which is proved to enhance the F‐actin assembly and to guide the cell migration. This novel mechanism advances the understanding of the role of collagen fibers in mechanotaxis of macrophages. Taken together, it has great potential for assisting biomaterial designs in developing new drug‐screening models and clinical strategies for cancer immune‐therapy. [ABSTRACT FROM AUTHOR]

Mechanisms of adaptive rearrangements of the fibrous extracellular matrix of connective tissues under microgravity practically remain unexplored, despite the most essential functions of the stroma existing to ensure the physiological activity of internal organs. Here we analyzed the biomaterial (the skin dermis) of C57BL/6J mice from the Rodent Research-4 experiment after a long stay in space flight. The biomaterial was fixed onboard the International Space Station. It was found that weightlessness resulted in a relative increase in type III collagen-rich fibers compared to other fibrous collagens in the skin. The number of mast cells in the skin did not change, but their secretory activity increased. At the same time, co-localization of mast cells with fibroblasts, as well as impregnated fibers, was reduced. Potential molecular–cellular causes of changes in the activity of fibrillogenesis under zero-gravity conditions and the slowdown of the polymerization of tropocollagen molecules into supramolecular fibrous structures, as well as a relative decrease in the number of fibrous structures with a predominant content of type-I collagen, are discussed. The data obtained evidence of the different sensitivity levels of the fibrous and cellular components of a specific tissue microenvironment of the skin to zero-gravity conditions. The obtained data should be taken into account in the systematic planning of long-term space missions in order to improve the prevention of undesirable effects of weightlessness. [ABSTRACT FROM AUTHOR]