Fibrous Tissue Structures Research Articles

Polarization enhancement mechanism from tissue staining in multispectral Mueller matrix microscopy.

Mueller matrix microscopy can provide comprehensive polarization-related optical and structural information of biomedical samples label-freely. Thus, it is regarded as an emerging powerful tool for pathological diagnosis. However, the staining dyes have different optical properties and staining mechanisms, which can put influence on Mueller matrix microscopic measurement. In this Letter, we quantitatively analyze the polarization enhancement mechanism from hematoxylin and eosin (H&E) staining in multispectral Mueller matrix microscopy. We examine the influence of hematoxylin and eosin dyes on Mueller matrix-derived polarization characteristics of fibrous tissue structures. Combined with Monte Carlo simulations, we explain how the dyes enhance diattenuation and linear retardance as the illumination wavelength changed. In addition, it is demonstrated that by choosing an appropriate incident wavelength, more visual Mueller matrix polarimetric information can be observed of the H&E stained tissue sample. The findings can lay the foundation for the future Mueller matrix-assisted digital pathology.

Influence of hematoxylin and eosin staining on linear birefringence measurement of fibrous tissue structures in polarization microscopy.

For microscopic polarization imaging of tissue slices, two types of samples are often prepared: one unstained tissue section for polarization imaging to avoid possible influence from staining dyes quantitatively and one hematoxylin-eosin (H&E) stained adjacent tissue section for histological diagnosis and structural feature identification. However, this sample preparation strategy requires high-quality adjacent tissue sections, and labeling the structural features on unstained tissue sections is impossible. With the fast development of data driven-based polarimetric analysis, which requires a large amount of pixel labeled images, a possible method is to directly use H&E stained slices, which are standard samples archived in clinical hospitals for polarization measurement. We aim to study the influence of hematoxylin and eosin staining on the linear birefringence measurement of fibrous tissue structures. We examine the linear birefringence properties of four pieces of adjacent bone tissue slices with abundant collagen fibers that are unstained, H&E stained, hematoxylin (H) stained, and eosin (E) stained. After obtaining the spatial maps of linear retardance values for the four tissue samples, we carry out a comparative study using a frequency distribution histogram and similarity analysis based on the Bhattacharyya coefficient to investigate how H&E staining affects the linear birefringence measurement of bone tissues. Linear retardance increased after H&E, H, or E staining (41.7%, 40.8%, and 72.5% increase, respectively). However, there is no significant change in the imaging contrast of linear retardance in bone tissues. The linear retardance values induced by birefringent collagen fibers can be enhanced after H&E, H, or E staining. However, the structural imaging contrasts based on linear retardance did not change significantly or the staining did not generate linear birefringence on the sample area without collagen. Therefore, it can be acceptable to prepare H&E stained slices for clinical applications of polarimetry based on such a mapping relationship.

Preparation of Teakwood Bending Components with Excellent Softening Properties by Vacuum Impregnation with Triethanolamine Compounding Solution

To study the softening bending properties and mechanism of teakwood, it was extractively pretreated by using superheated steam, the triethanolamine compound was used as a softening solution, which was infiltrated into the wood by vacuum impregnation and synergistically softened through saturated steam to improve the bending properties of teakwood. Analysis by Fourier transform infrared spectroscopy (FTIR), Carbon 13 nuclear magnetic resonance (13C NMR), and X-ray photoelectron spectroscopy (XPS) showed that the synergistic softening treatment elevated the content of O and N elements in the softening solution and together with the C elements in the wood, formed C-NH2 and C-N bonds, which increased the molecular activity and improved the softening properties of teakwood. Scanning electron microscope (SEM) observations revealed that the outer conduits, cell walls, and fibrous tissue structures of the teakwood were stretched after softening and bending, and even microcracks of different degrees were formed between the cell walls. According to the load–deformation relationship of teakwood softening bending, the stress–strain relationship was theoretically derived and the bifold constitutive model of teakwood bending was constructed after fitting the constitutive relationship data, the integrated correlation coefficient R2 was 96.25%, which proved that the present model can better simulate the constitutive relationship of teakwood in bending.

The comprehensive performance and strengthening mechanism of the columnar crystal Cu-Ni-Si alloy after two large deformation rates of cryogenic rolling-aging

In order to improve the strength and electrical conductivity of Cu-Ni-Si alloy, the columnar crystalline C70250 copper alloy strip suffer from two deep cryogenic rolling-aging treatments with large deformation, and the relationship between the cryogenic rolling-aging process and microscopic structure, mechanical, conductive properties is studied, and the precipitation behavior is analyzed. The research findings show that the columnar crystalline C70250 copper alloy produced by continuous directional solidification can be directly processed by two cryogenic rolling-aging treatment with large deformation, eliminating the traditional solution treatment process and obtaining a fibrous tissue structures containing high-density dislocations and multi-scale precipitates, the yield strength, tensile strength and electrical conductivity of the alloy reached 879 MPa, 923 MPa and 38.7 % IACS respectively, combination of strength and electrical conductivity is excellent. Two deep cryogenic rolling with large deformation can force the matrix to change to amorphous, favorable to atomic diffusion. Solute atoms are continuously transformed into Ni2Si phase and Cu atoms are continuously expelled, forming large-sized pure Ni2Si precipitated phase and small-sized NiSi cluster phase containing Cu atoms, which together impede dislocation movement and reinforce alloy. With the uniform precipitation of multi-scale nano-precipitation phases and reduction of grain boundary density, the electrical conductivity along the rolling direction is significantly reduced.

FIBROSIS: POLYETIOLOGIC COMPLICATION WITH COMMON DENOMINATOR

State of the problem. The growth of fibrous connective tissue is a common complication of various pathological processes, which significantly complicates recovery and is one of the leading causes of death. Despite many years of research, the process of fibrosis development remains insufficiently studied and contains a large number of “white spots”. Fibrosis is characterized by unpredictability, propensity to grow and low level of the replacement by normal connective tissue. The structure of fibrous tissue, its differences from normal and the reasons for the formation of these differences deserve no less attention. The formation of fibrous tissue is preceded by the process of endogenous intoxication – the formation and accumulation of various abnormal metabolites. Among the latter, the leading place belongs to proteins and peptides, whose structure is disrupted and destabilized. It is known that destabilized proteins are prone to aggregation. This process, contrary to popular belief, is not chaotic, but is subject to certain laws and is aimed at minimizing of free energy. With regard of the latter circumstance a definite favorite is the formation of β-structured fibrils, which occupy almost the lowest energy level among protein conformational states. Such fibrils are characterized by insolubility, resistance to proteolysis, immunogenicity and the ability to autochthonous growth due to sorption and conformational rearrangement of soluble proteins. A classic example of such aggregation is amyloid formation, but there are good reasons to assume similar processes in the formation of other pathological tissues. The aim of the work was to verify experimentally the presence of β-structured protein aggregates in fibrous tissues, which differ in etiology. The methodical part included the selection of surgical material, its fixation in 10 % formaldehyde solution, preparation of Congo-stained red histological specimens and microscopic examination in light, polarization and fluorescence modes. Results. The presence of β-structured protein aggregates in fibrous tissues formed due to local chronic inflammation, viral infection and side effects of drugs has been proven experimentally. The identified phenomenon allows us to approach the understanding of the mechanisms of fibrosis development and to postulate a key role of regular aggregation of destabilized proteins. Conclusions. The obtained data testifies to a general and integral participation of β-structured protein aggregates in the formation of fibrous tissues of different etiologies. The presence of these deposits in fibrous tissues formed due to local chronic inflammation, viral infection and side effects of the cytostatic doxorubicin has been shown. The leading role of violation of protein homeostasis and local accumulation of structurally damaged proteins as a prerequisite for autochthonous aggregation process is discussed. The expediency of fluorescence microscopy has been shown, which significantly expands the possibilities of detecting with the help of the Congo red of nanosized β-structured protein aggregates, which are invisible due to Abbe's limitations in light and polarization microscopy. Key words: fibrosis, keloidosis, Peyronie’s disease, Covid-19, cytostatics, nanoparticles.

Optical scatter imaging of resected breast tumor structures matches the patterns of micro-computed tomography

In patients undergoing breast-conserving surgery (BCS), the rate of re-excision procedures to remove residual tumor left behind after initial resection can be high. Projection radiography, and recently, volumetric x-ray imaging are used to assess margin adequacy, but x-ray imaging lacks contrast between healthy, abnormal benign, and malignant fibrous tissues important for surgical decision making. The purpose of this study was to compare micro-CT and optical scatter imagery of surgical breast specimens and to demonstrate enhanced contrast-to intra-tumoral morphologies and tumor boundary features revealed by optical scatter imaging. A total of 57 breast tumor slices from 57 patients were imaged ex vivo by spatially co-registered micro-CT and optical scatter scanning. Optical scatter exhibited greater similarity with micro-CT in 89% (51/57) of specimens versus diffuse white light (DWL) luminance using mutual information (mean ± standard deviation of 0.48 ± 0.21 versus 0.24 ± 0.12; p < 0.001) and in 81% (46/57) of specimens using the Sørensen–Dice coefficient (0.48 ± 0.21 versus 0.33 ± 0.18; p < 0.001). The coefficient of variation (CV) quantified the feature content in each image. Optical scatter exhibited the highest CV in every specimen (optical scatter: 0.70 ± 0.17; diffuse luminance: 0.24 ± 01; micro-CT: 0.15 ± 0.03 for micro-CT; p < 0.001). Optical scatter also exhibited the highest contrast ratios across representative tumor boundaries with adjacent healthy/benign fibrous tissues (1.5–3.7 for optical scatter; 1.0–1.1 for diffuse luminance; 1.0–1.1 for micro-CT). The two main findings from this study were: first, optical scatter contrast was in general similar to the radiological view of the tissue relative to DWL imaging; and second, optical scatter revealed additional features associated with fibrous tissue structures of similar radiodensity that may be relevant to diagnosis. The value of micro-CT lies in its rapid three-dimensional scanning of specimen morphology, and combined with optical scatter imaging with sensitivity to fibrous surface tissues, may be an attractive solution for margin assessment during BCS.

Noise reduction and quantification of fiber orientations in greyscale images.

Quantification of the angular orientation distribution of fibrous tissue structures in scientific images benefits from the Fourier image analysis to obtain quantitative information. Measurement uncertainties represent a major challenge and need to be considered by propagating them in order to determine an adaptive anisotropic Fourier filter. Our adaptive filter method (AF) is based on the maximum relative uncertainty δcut of the power spectrum as well as a weighted radial sum with weighting factor α. We use a Monte-Carlo simulation to obtain realistic greyscale images that include defined variations in fiber thickness, length, and angular dispersion as well as variations in noise. From this simulation the best agreement between predefined and derived angular orientation distribution is found for evaluation parameters δcut = 2.1% and α = 1.5. The resulting cumulative orientation distribution was modeled by a sigmoid function to obtain the mean angle and the fiber dispersion. A comparison to a state-of-the-art band-pass method revealed that the AF method is more suitable for the application on greyscale fiber images, since the error of the fiber dispersion significantly decreased from (33.9 ± 26.5)% to (13.2 ± 12.7)%. Both methods were found to accurately quantify the mean fiber orientation with an error of (1.9 ± 1.5)° and (2.3 ± 2.1)° in case of the AF and the band-pass method, respectively. We demonstrate that the AF method is able to accurately quantify the fiber orientation distribution in in vivo second-harmonic generation images of dermal collagen with a mean fiber orientation error of (6.0 ± 4.0)° and a dispersion error of (9.3 ± 12.1)%.

Illustrative uncertainty visualization of DTI fiber pathways

Diffusion Tensor Imaging (DTI) and fiber tracking provide unique insight into the 3D structure of fibrous tissues in the brain. However, the output of fiber tracking contains a significant amount of uncertainty accumulated in the various steps of the processing pipeline. Existing DTI visualization methods do not present these uncertainties to the end-user. This creates a false impression of precision and accuracy that can have serious consequences in applications that rely heavily on risk assessment and decision-making, such as neurosurgery. On the other hand, adding uncertainty to an already complex visualization can easily lead to information overload and visual clutter. In this work, we propose Illustrative Confidence Intervals to reduce the complexity of the visualization and present only those aspects of uncertainty that are of interest to the user. We look specifically at the uncertainty in fiber shape due to noise and modeling errors. To demonstrate the flexibility of our framework, we compute this uncertainty in two different ways, based on (1) fiber distance and (2) the probability of a fiber connection between two brain regions. We provide the user with interactive tools to define multiple confidence intervals, specify visual styles and explore the uncertainty with a Focus+Context approach. Finally, we have conducted a user evaluation with three neurosurgeons to evaluate the added value of our visualization.

Strength and Structure of Fibrous Tissues under Mechanical Stimuli(Micro- and Nano-biomechanics)

Strength and Structure of Fibrous Tissues under Mechanical Stimuli(Micro- and Nano-biomechanics)

The role of mechanics in biological and biologically inspired materials

In the development of new materials, researchers have recently turned to nature for inspiration and assistance. A special emphasis has been placed on understanding the development of biological materials from the traditional correlation of structure to property, as well as correlating structure to functionality. The natural evolution of structure in biological materials is guided by the interaction between these materials and their environment. What is most notable about natural materials is the way in which the structure is able to adapt at a wide range of length scales. Much of the interaction that biological materials experience occurs through mechanical contact. Therefore, to develop biologically inspired materials it is necessary to quantify the mechanical behavior of and mechanical influences on biological structures with the intention of defining the natural structure-property-functionality relationship for these materials. In particular, the role mechanics has assumed in understanding biological materials, and the biologically inspired materials developed from this knowledge, will be clarified. The following will serve to elucidate on this role: the helical structure of fibrous tissue, the multi-scale structure of wood, and the biologically inspired optimal structure of functionally graded materials.

Skeletal structural adaptations to mechanical usage (SATMU): 4. Mechanical influences on intact fibrous tissues

This paper proposes that the growth in length of living fibrous tissue structures (tendon, ligament, fascia) responds primarily to circulating systemic rather than mechanical factors. However, growth of the thickness of those structures responds primarily to their mechanical tension loads in the special sense that, when the tissue's typical peak mechanical strains exceed a threshold value, its cells begin to add new collagen to increase its thickness, strength, and tension stiffness. When subsequent peak strains reduce to the threshold value, then further additions of collagen stop. That process defines mechanically controlled modeling of fibrous tissues. The collagen in these tissues can also develop mechanical microdamage (MDx) under repeated tension load-deload cycles. Special maintenance mechanisms normally repair that MDx to prevent accumulations that would threaten structural integrity. As a result, spontaneous complete ruptures of these structures can happen when MDx production exceeds its repair. These maintenance mechanisms also prevent gradual stretching under continuous tension loads, a process the author suggests calling creep compensation. When the creep compensation mechanism becomes incompetent, structures can stretch under continuous loads; when it becomes overactive, contractures can occur. The above meld of fact and inference provides the kernel of a general theory for the responses of the architecture and mechanical competence of intact fibrous tissues to mechanical usage.

Osteogenesis Irnperfecta

The minimum effective strain (MES) constitutes a threshold that separates biomechanically acceptable from unacceptable strains on growing bone and fibrous tissues. Strains above that threshold affect modeling and remodeling activities in ways that change the size and configuration of growing bones, tendons, ligaments, and fascia to fit their new mechanical usage and return their strains to the threshold level. Were that threshold set too high from birth, the effects of normal function on remodeling and modeling should lead to thin fibrous tissue structures, to slender, osteopenic diaphyses and spongiosa, and to increased fragility. Those and other predictable set point effects fit so precisely many of the known hard and soft tissue abnormalities of osteogenesis imperfecta patients, that an elevated MES set point may be a heretofore unrecognized basic pathogenetic factor in that disease.

Some observations on the surface structure of collagen in hypertrophic scars.

The structure of the interface between epidermis and dermis was examined in normal skin and in hypertrophic scars using the scanning electron microscope. The hypertrophic scar was found to show a completely different structure of fibrous tissue (collagen) at this surface when compared to normal skin. As the hypertrophic scar matured this surface was remodelled to resemble more closely the surface observed in normal skin. The study suggests that the attachment of epidermal cells to the surface of the fibrous tissue developing in the burn wound may be an important aspect of the pathogenesis of hypertrophic scarring.

NEWER ASPECTS OF BENIGN TUMORS OF THE BREAST

BENIGN tumefactions of breast tissue and its integument may be divided into: A. Mammary dysplasia, resulting from abnormalities in the secretion of the ovarian hormones. This is exemplified by: (1) Mastodynia—painful mammary tissue of increased density. (2) Adenosis—nodosities from epithelial hyperplasia with small cysts. (3) Cystic disease—one or more cysts of appreciable size resulting from secretory changes. B. Benign neoplasia, characterized by true benign tumor formations. Examples of this are: (1) Benign fibroadenoma with a structure of fibrous tissue and ducts. (2) Benign intracystic papillomas, which include (1) papillary invaginations of larger ducts, (2) intracystic papillomas and (3) papillary hyperplasia which occurs in adenosis of the breast. (3) Benign nonindigenous tumors of the breast, involving (a) fat (lipoma and xanthoma), (b) lymphatic vessels (angioma, lymphangioma and lymphoma), (c) muscles (leiomyoma and myoblastoma), (d) skeletal mesenchyme (chondroma and osteoma) and (e) skin

Effect of Absolute and Partial Vitamin C Deficiency on Healing of Wounds.

It is now well established that the intercellular substances in general, and the collagen of all fibrous tissue structures in particular require ascorbic acid for their production and maintenance. Aschoff and Koch1 made thorough postmortem studies of World War soldiers who had died of scurvy, and demonstrated constant pathological changes in the supporting tissues of the body. Hojer2 found a general atrophy of the connective tissue in scorbutic guinea pigs, and pointed out for the first time a general deficiency in the formation of collagen. In a series of more recent communications Wolbach345 and his collaborators confirmed the observations of Hojer, and conclusively showed that ascorbic acid is intimately concerned with the synthesis and maintenance of intercellular supporting materials. Jeney and Toro,6 when they added ascorbic acid to the nutrient medium of a culture of fibroblasts in vitro, found a marked increase in the number of collagen fibrils that were produced.Since the repair and tensile stren...