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Food spoilage is mainly caused by microorganisms, such as bacteria. In this study, we measure the autofluorescence in meat samples longitudinally over a week in an attempt to develop a method to rapidly detect meat spoilage using fluorescence spectroscopy. Meat food is a biological tissue, which contains intrinsic fluorophores, such as tryptophan, collagen, nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) etc. As meat spoils, it undergoes various morphological and chemical changes. The concentrations of the native fluorophores present in a sample may change. In particular, the changes in NADH and FAD are associated with microbial metabolism, which is the most important process of the bacteria in food spoilage. Such changes may be revealed by fluorescence spectroscopy and used to indicate the status of meat spoilage. Therefore, such native fluorophores may be unique, reliable and non-subjective indicators for detection of spoiled meat. The results of the study show that the relative concentrations of all above fluorophores change as the meat samples kept in room temperature (~19°C) spoil. The changes become more rapidly after about two days. For the meat samples kept in a freezer (~ -12°C), the changes are much less or even unnoticeable over a-week-long storage.

In this study, we evaluated the synergistic effect of ginger and nifedipine on anti-platelet aggregation in normal human volunteers and hypertensive patients. The results showed that the percentage of platelet aggregation induced by collagen, ADP and epinephrine in hypertensive patients was larger than that in normal volunteers. Either aspirin or ginger could potentiate the anti-platelet aggregation effect of nifedipine in normal volunteer and hypertensive patients. These results suggested that ginger and nifedipine possessed synergistic effect on anti-platelet aggregation. A combination of 1 g ginger with 10 mg nifedipine per day could be valuable for cardiovascular and cerebrovascular complication due to platelet aggregation.

Wound healing is a complex process orchestrated by the regeneration of the epithelium and the remodeling of the extracellular matrix through processes like collagen deposition. Galla Rhois has been widely used in traditional Korean medicine for its various pharmacological effects, including an anticoccidial effect, however, little is known about its healing activity. The purpose of this study was to determine the effects of Galla Rhois ethanol extract (GRE) on wound healing activities, including H₂O₂-induced oxidative stress, cell migration, and lactate dehydrogenase (LDH) release assays using human keratinocyte (HaCaT) and dermal fibroblasts (CCD-986SK). In addition, total soluble collagen deposition and collagen gene expression for Type I and III collagen were evaluated in CCD-986SK. Total tannin and flavonoid contents for GRE were measured. GRE induced a significant increase in the number and migration of cells, along with a decrease in cell death and LDH release. In addition, it also induced the over-expression of collagen Type I and III mRNA and caused increased synthesis of total soluble collagen. The contents of total tannin and flavonoid for GRE were 55.7% ($556.99\pm 2.60$mg/g) and 62.9% ($62.89\pm 1.35$mg/g), respectively. The results suggest that GRE can cause accelerated wound healing by increasing cell survival, proliferation, migration, and collagen synthesis along with a potential anti-oxidant property. This evidence provides novel insight into natural therapy for tissue injury.

Many kinds of materials are currently used as artificial bone substitutes. Hydroxyapatite (HA), the same as the main inorganic component of bone, is one of commonly used bio-ceramics and has excellent bioactivity and biocompatibility with hard tissues. However, it has problems as the bone filler or bone tissue-engineering scaffold due to low fracture toughness and low degradation rate. Recently, biodegradable materials for bone tissue have been developed to respond the requirement. Collagen, the same as the main organic component of bone, is biocompatible, biodegradable and promotes cell adhesion. A composites associated with HA is expected to have early osteoconduction and bone replacement ability. The present study was to fabricate bone-like composites consist of HA and collagen. Besides the ossiferous ability of the material in vivo is evaluated by using rabbits. Bone-like composites were successfully fabricated in this study, associating the collagen with HA. And the composites presented good osteoconductive and bone replacement potential.

We have here an insight into the features of molecular structures of bio-polymers with α-helix structure using infrared spectrum and elucidated theoretically, its relationship with bio-functions. In this case, we analyzed first the features of molecular structure of collagen and collected further the infrared spectrum of absorption of collagen and bovine serum albumin containing α-helix conformation in 400–4000 cm^-1 as well as their changes of strength of infrared absorption with varying temperatures using Fourier Transform–Infrared (FT-IR) spectrometers in the region of 15–95°C. The results show that there is a new band of 1650 cm^-1 close to the amide-I band of 1666 cm^-1 or 1670 cm^-1 in these bio-polymers, its strength decreases exponentially with increasing temperature of the systems, which can be expressed by exp[-(0.437 + 8.987 × 10^-6 T²)], but 1666 cm^-1 band increases linearly with increasing temperature. We calculated the energy spectrum of the protein molecules with α-helix conformation using the Soliton Theory of bio-energy transport, which are basically same with the experimental results measured by us. From these results and soliton theory we can conclude that the nonlinear soliton excitation, corresponding to 1650 cm^-1 band and the exciton excitation, is related to 1666 cm^-1 band, exists in the collagen and bovine serum albumin. In the meanwhile, these results also verified that the soliton theory of bio-energy transport along α-helix bio-polymers is appropriate to the protein molecules with α-helix conformation. Therefore, the studied results are helpful to elucidate the relationship between the molecular structure and bio-function of these bio-polymers.

Hypertrophic scar and keloids have affected patients and frustrated physicians for centuries. Hypertrophic scar (HSc) and keloids are a major problem for patients who survive extensive thermal and traumatic skin injuries. HSc and other fibroproliferative disorders are associated with excessive accumulation of collagen and extracellular matrix proteins due to an imbalance between synthesis and degradation. The therapeutic management of hypertrophic scars and keloids include occlusive dressings, compression therapy, intralesional corticosteroid injections, cryosurgery, excision, radiation therapy, laser therapy, interferon therapy and other promising lesser known therapies directed at collagen synthesis. In this study we investigated the effect of phenergan (promethazine hydrochloride) as one of the most potent histamine antagonists on cell proliferation, DNA synthesis and collagen production in fibroblast isolated from human post burn hypertrophic scar, keloids and normal skin. The proliferation of normal skin fibroblast was slightly decreased but hypertrophic scar and keloids showed significant (p<0.001) level of decrease after 72 hours of phenergan (750 μM) treatment. The results of DNA synthesis also significantly (p<0.001) decreased in hypertrophic scar and keloid fibroblasts. Phenergan (1.5 mM) decreased the collagen synthesis upto 61% and 66% in HSc and keloids in comparison to normal skin fibroblast, which showed reduction of 38% after 72 hours. Improved understanding of such regulatory mechanisms may eventually be of therapeutic significance in the control of hypertrophic scar and keloids.

The development of shape and form is intrinsic to the structure and function of many biological macromolecules including tubulin, actin and collagen. Type I collagen is a major structural protein in the body, providing mechanical strength for tissues such as bone and skin. It is present in the form of fibrils which display a regular banding pattern known as D-periodicity (where D = 67 nm). Type I collagen is a long rod-like molecule (300 nm ×1.5 nm) consisting of a triple helix formed from three polypeptide chains. In vivo and in vitro studies have shown that collagen molecules self-assemble in a regular D-staggered array to form striated fibrils. Further studies have shown that the process, termed fibrillogenesis, is entropy driven. A model based on diffusion limited aggregation was used to investigate the properties of rod self-assembly. This simple model reproduced several experimentally observed features of collagen fibril morphology including a linear mass/unit length profile and a preference for tip growth.

Nineteen fresh frozen adult human flexor digitorum profundus (FDP) tendons in Zone II were studied to compare the differences in material properties between the dorsal (dFDP) and palmar (pFDP) side of each tendon biomechanically, biochemically and histologically. We have found that tissue from the dorsal side of each flexor tendon has (1) greater strength; (2) less collagen crosslinking (hydroxypyridinium); and (3) a larger single bundle cross-sectional area than tissue from the palmar side of the same tendon. These data clearly demonstrate that the dorsal and palmar sides of the adult human (FDP) tendon in Zone II differ materially. These differences suggest that there may be biomechanical advantages in placing core sutures dorsally when repairing flexor tendons, a technique that we have previously described.

Rotator cuff repair (RCR) is a crucial surgical procedure, but has unacceptable mechanical failure rates between 25–60%. Examining supplemental synergistic interventions, such as biological augmentations (ex: growth factors) to improve fibrocartilage formation rather than scar tissue formation, would make tears more amenable to surgical repair. Due to the large number of agents and application methods (and times), improved techniques are needed for assessing RCR in animals. In particular, high-resolution real-time imaging is needed to guide tissue engineering in animal models. Optical coherence tomography (OCT) is well suited for this role, with resolutions 25 × greater than any clinical imaging modality and an ability to identify organized collagen with polarization sensitive techniques. For example, it can determine severe collagen depletion in visually normal tendons. The images here show the first OCT and PS-OCT of the rotator cuff in male Wistar rats. The structure of the supraspinatus tendon, enthesis, and humerus are well defined. For histological comparison, this sample was stained with both Masson's Trichrome, to expose any structural abnormalities, and Picrosirius Red, to determine collagen content using a polarization filter. OCT studies offer the potential of understanding RCR failure mechanisms and potential tissue altering agents, substantially impacting outcomes.

Cartilage can redistribute human body’s daily loads and decrease the friction force in the diarthrodial joints. However, it may be injured due to trauma, sports injury, biomechanical imbalance, and genetic disease. Microfracture (MF), osteochondral autograft transplantation (OAT), and autologous chondrocyte implantation (ACI) are the most common treatment procedures in the hospital. Recently, the concept of tissue engineering involving the combination of cells, scaffolds, and bioactive signals has inspired researchers. Our team of researchers synthesized a tri-copolymer from biological polymer by using gelatin, chondroitin-6-sulfate, and hyaluronic acid through cross-linking reaction. Lacuna formation could be seen in the tri-copolymer surrounding the chondrocytes, and some newly formed glycosaminoglycan was found in the engineered cartilage. Considering the dedifferentiation possibility of chondrocyte, bone marrow mesenchymal stem cells (BMSCs) become an ideal cell source for cartilage tissue regeneration, since they can be easily harvested from adult tissue, and be expanded in vitro. In an in-vivo porcine pilot study, the results showed that the defect site could be regenerated by BMSCs/collagen gel, and is formed with fibro/hyaline mixed cartilage tissue after implantation for six months. Several clinical studies using BMSCs for cartilage defect treatment were also conducted recently; clinical outcomes such as IKDC, Lysholm, and Tegner scores improved when the cartilage defects were repaired by several millions of mesenchymal stem cells, and there is no tumor formation after being treated with BMSCs during the 10-year follow-up. Moreover, recently a commercial BMSCs/collagen gel composite for cartilage repair was developed in Taiwan and clinical trial was conducted in 2008; the results showed that there is an improvement in IKDC and MRI scores during the nine-year follow-up. It seems that using an engineered cartilage made from BMSCs/collagen gel for cartilage defect treatment is a promising method.

The chemical reactions and physical effects involved in the cessation of bone formation with age, the formation of blood and other cells in bone marrow plus the development of osteoporosis and the link of the latter to anaemia and diabetes are reconsidered with respect to the physical and biochemical conditions present in the human body.

The present study was performed to establish whether intact human tendons exhibit time-dependent tensile properties, as they do in the in vitro state. Measurements were taken in seven men and involved ultrasound-based recording of the gastrocnemius tendon elongation during three sets of five repeated isometric plantarflexion contractions elicited by tetanic electrical stimulation. The plantarflexion moment corresponding to the tendon elongation in the fifth contraction presented a pattern dependent on the voltage applied: it was approximately constant when applying 50% of maximal voltage, but it decreased curvilinearly as a function of contraction number when applying 70 and 100% of maximal voltage, reaching in the fifth contraction 84% of the plantarflexion moment corresponding to the elongation examined in the first contraction. These results suggest that, once a threshold tendon elongation is undergone, in vivo tendons may exhibit substantial viscoelasticity. The present findings have implications for muscle and joint function and need to be accounted for by musculoskeletal models.

There have been no previous reports of tendon tissue engineering using mesenchymal stem cells (MSCs) with regard to quantitative evaluation of protein expression levels and observation of derived extracellular matrix (ECM) state. Therefore, we approached tendon tissue engineering from both perspectives. Human bone marrow MSCs (hBMSCs) were subjected to 8% or 10% cyclic stretching at 1 Hz to promote differentiation into tenocytes and ECM production. The type I collagen (Col I) and Tenascin-C (Tnc) protein expression levels were evaluated quantitatively by enzyme-linked immunosorbent assay (ELISA). Confocal fluorescence microscopy was employed to observe the derived ECM state. Col I state derived from 10%-stretched cells as ECM was elongated like actual tendon ECM, although the quantitative protein expression levels were slightly higher in 8%-stretched cells. The results suggested that the optimal uniaxial stretching ratio was different between protein expression levels and derived ECM state. Therefore, it is important to pay attention to both protein expression levels and ECM state in tendon tissue engineering.

Bone is a multiscale combination of collagen molecules merged with mineral crystals. Its high rigidity and stability stem amply from its polymeric organic matrix and secondly from the connections established between interdifferent and intradifferent scale components through cross-links. Several studies have shown that the cross-links inhibition results in a reduction in strength of bone but they do not quantify the degree to which these connections contribute to the bone rigidity and toughness. This report is classified among the few works that measure the cross-links multiscale impact on the ultrastructure bone mechanical behavior.

This work aims firstly to study the effect of cross-links at the molecule scale and secondly to gather from literature studies results handling with cross-links effects on the other bone ultrastructure scales in order to reveal the multiscale effect of cross-links. This study proves that cross-links increasing number improves the mechanical performance of each scale of bone ultrastructure. On the other hand, cross-links have a multiscale contribution that depends on its rank related to existing cross-links connecting the same geometries and it depends on mechanical characteristics of geometries connected.

Pathological analysis as well as biomechanical methods are powerful approaches for collagen assessment, which plays an important role in understanding the wound healing process and choosing a treatment method in clinical situations. Due to the limitations of preparing and evaluating pathological images, this study was designed to establish a machine learning technique to predict the wound collagen content through its biomechanical parameters. For this purpose, the artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) were compared. The wound was created with an incision on the back of 30 male BALB/c mice. On the 7th and 14th days, animals were sacrificed and 60 wound tissue samples were evaluated using histopathological and biomechanical methods to quantify the amount of collagen and wound tensile strength to feed the ANN and ANFIS developed models. Based on the results, both models have appropriate performance to predict the wound collagen content. However, the comparison of coefficient of determination ($R^2$) and root mean square error (RMSE) for testing dataset revealed that ANN ($R^2=0.95$, $\mathrm{\text{RMSE}}=0.29$) had more prediction capability than ANFIS ($R^2=0.84$, $\mathrm{\text{RMSE}}=0.87$). As a decision support system, ANN model could assist in the evaluation of wound healing process with collagen values prediction.

Theoretical calculations have been carried out to investigate the effect of the 4(R)-substituents (OH, F, NH₂, and ) in proline on the stability of the collagen triple helix. A series of substituted proline models were studied first with density functional (B3LYP/6-31+G*) calculations. The solvent effect was studied using the SCIPCM method. While the F, OH and NH₂ groups increase the stability of the trans-up conformation with respect to the trans-down conformation, appears to favor the trans-down conformation in an aqueous solution. Second, the triple helices of the tripeptide models, Ac–Pro–Pro(X)–Gly–H with the two proline residues in the down/down and down/up puckering conformations, were optimized with a repeating unit approach using the HF/6-31G* method. For the Ac–Pro–Pro–Gly–H model peptide, the calculated binding energies of the two triple helices with the different puckering modes are similar. All four substituents, F, OH, NH₂, and , considerably increased the binding energy of the down/up helix, but only stabilizes the down/down triple helix. Our calculations indicate that the inter-chain electrostatic interactions involving the 4(R)-substituents play an important role in stabilizing triple helical collagen models and allow the rationalization of all available experimental observations. Further model studies indicate that the substituent effects by the F, OH and NH₂ substituents are local while the effect of is long-range in nature.

This discussion about diagnostic tests for cancer incorporates a powerful branch of Physics namely X-ray diffraction. Although this technique was used to solve the DNA structure using the X-ray diffraction pictures of Rosalind Franklin,¹ and the structure of vitamin B12 by Dorothy Hodgkin² and hosts of other medical related structures, it is poorly understood by the general medical profession and the community at large. To the nonphysicist the patterns appear to have no relation to the results produced. It might as well be written in Greek. The well-known quote of Poincaré, the famous French mathematician and scientist, in 1885 comes to mind: "Science is built up with facts as a house is with stones. But a collection of facts is no more a science than a heap of stones is a house."

In order therefore to build a true understanding of this powerful technique it is necessary to build a firm understanding of the basic facts about this technique, so that the final results will be clear to all, as they will be held up by a firm house of knowledge. So let us take up the first stone.

Type I collagen fibrils have circular cross sections with radii mostly distributed in between 50 and 100 nm and are characterized by an axial banding pattern with a period of 67 nm. The constituent long molecules of those fibrils, the so-called triple helices, are densely packed but their nature is such that their assembly must conciliate two conflicting requirements. One is a double-twist around the axis of the fibril induced by their chirality and the other is a periodic layered organization, corresponding to the axial banding, built by specific lateral interactions. We examine here how such a conflict could contribute to the control of the radius of a fibril. We develop our analysis with the help of two geometrical archetypes: the Hopf fibration and the algorithm of phyllotaxis. The first one provides an ideal template for a twisted bundle of fibres and the second ensures the best homogeneity and local isotropy possible for a twisted dense packing with circular symmetry. This approach shows that, as the radius of a fibril with constant double-twist increases, the periodic layered organization can not be preserved without moving from planar to helicoidal configurations. Such changes of configurations are indeed made possible by the edge dislocations naturally present in the phyllotactic pattern. The distribution of those defects is such that the lateral growth of a fibril should stay limited in the observed range. Because of our limited knowledge about the elastic constants involved, this purely geometrical development stays at a quite conjectural level.

Tumor invasion, the process by which tumor cells break away from their primary tumor and gain access to vascular systems, is an important step in cancer metastasis. Most current 3D tumor invasion assays consisted of a single tumor cell embedded within an extracellular matrix (ECM). These assays taught us much of what we know today on how key biophysical (e.g., ECM stiffness) and biochemical (e.g., cytokine gradients) parameters within the tumor microenvironment guided and regulated tumor invasion. One limitation of the single tumor cell invasion assays was that it did not account for cell–cell adhesion within the tumor. In this paper, we developed a micrometer scale 3D co-culture spheroid invasion assay that recapitulated physiologically realistic tumor microenvironment and was compatible with microscopic imaging. Micrometer scale co-culture spheroids (1:1 ratio of metastatic breast cancer MDA-MB-231 and non-tumorigenic epithelial MCF-10A cells) were made using an array of microwells, and then were embedded within a collagen matrix in a microfluidic platform. Real time imaging of tumor spheroid invasion revealed that the spatial distribution of the two cell types within the tumor spheroid critically regulated tumor invasion. This work linked tumor architecture with tumor invasion and highlighted the importance of the biophysical cues within the bulk of the tumor in tumor invasion.

Collagen is an endogenous fluorophore that accounts for about 70% of all proteins of human skin, so it can be an optical marker for structural abnormalities in tissues registered by laser fluorescent diagnostics in vivo. Using the examples of such abnormalities as scars, scleroderma and basal cell carcinoma, this study shows the differences between coefficients of fluorescent contrast k_f(λ) of abnormalities from the ones for healthy tissues at fluorescent excitation wavelength 360–380 nm. It is shown that scars and dysplasia are characterized by reduced values of k_f(λ) for collagen. Due to high turbidity and phase heterogeneousness as well as variation of parameters of blood microcirculation and concentrations of other related chromophores, there is no mathematical model that precisely calculates the concentration of collagen in tissues only with the use of the value of fluorescent signal intensity. So, probably, the best marker of the pathological process is a comprehensive representation of k_f(λ) for all endogenous fluorophores, i.e., for all used visible wavelengths. In this case identification of abnormal tissues is quite possible by detecting some deviations of coefficients k_f(λ) for the optically identical and symmetrical regions of the human body.