2D Raman-THz Spectroscopy of Binary CHBr3-MeOH Solvent Mixture.

Hybrid 2D Raman-terahertz (THz) spectroscopy is used to measure the interactions between two solvents paired in the binary CHBr3-MeOH mixture in the frequency range of 1-7 THz. Changes in the cross peak signature are monitored, originating from the coupling of an intramolecular bending mode of CHBr3 to the collective intermolecular degrees of freedom of the mixture. The appearance of a new cross peak in the 2D spectrum measured for solvent mixture with MeOH molar fraction of 0.3 indicates a coupling to a new set of low-frequency modes formed due to the hydrogen bond interactions between the two solvents. This interpretation is supported by the measurement of the CHBr3-CS2 binary solvent mixture as well as by 1D absorption measurements of neat MeOH.

Glabridin triggers over-expression of MCA1 and NUC1 genes in Candida glabrata: Is it an apoptosis inducer?

The growing trends of emergence of antifungal-resistant Candida strains has recently been inspired the researchers to design new antifungal agents with novel mechanisms of action. Glabridin is an originally natural substrate with multiple biological activities which propose it as a novel anticancer, antimicrobial and antifungal agent. In the present study, the antifungal effect of glabridin against Candida glabrata isolates and its possible mechanism of action were investigated. The minimum inhibitory concentrations (MIC) for glabridin against fluconazole-resistant and fluconazole-SDD strains of C. glabrata were investigated using the Clinical and laboratory standards institute document M27-A3 and M27-S4 as a guideline. Possible alternations in the expression of two critical genes involved in yeast apoptosis, MCA1 and NUC1, were assayed by real-time PCR. DNA damage and chromatin condensation was investigated using DAPI staining. Although glabridin led to a significant decrease in MICs against fluconazole-resistant C. glabrata (MIC50: 8µg/mL), no significant decreased was shown for fluconazole-SDD strains. Therefore, a distinct azole-independent mechanism could be responsible for the inhibitory activity of glabridin. Overexpression of MCA1 and NUC1 genes in addition to DNA damage and chromatin condensation suggesting the involvement of apoptosis signaling in C. glabrata stains exposed to glabridin. This study suggests that glabridin might be considered as a novel naturally originated agent to fight against fluconazole-resistance C. glabrata strains.

The role of transforming growth factor beta 1 in communicating and non-communicating hydrocele.

PURPOSE: Repair of inguinal hernia and hydrocele are one of the most common operations performed by surgeons. However, the exact biological mechanism responsible for the closure of processus vaginalis (PV) is not completely understood. Transforming growth factor beta 1 (TGF-ß1) is a potent fibrogenic agent and probably stimulate fibrosis and disappearing of PV. METHODS: From September 2012 to December 2014, all boys from 1 to 5 years who were referred for surgery of hydrocele were divided into two groups of communicating (HC) or non-communicating hydrocele (HNC). During surgery, the fluid in the sac was aspirated and sent for biochemical evaluation including calcium, phosphorus, total protein, and TGF-ß1. Finally, a biopsy of the sac was sent to the pathology. The results obtained were considered statistically significant (P < 0.05). RESULTS: The patients were categorized into two groups of non-communicating hydrocele, including 43 patients and communicating, including 33. The patients studied were aged 1-5 years (mean 33.6 months). Biochemical tests on hydrocele fluid showed no significant difference in the levels of calcium, phosphorus, total protein, and bilirubin between two groups. However, mean TGF-ß1 in NHC was found to be 53.45-114.28 pg/ml in HC group. A statistically significant difference (P = 0.04) was obtained. Furthermore, the study showed higher amounts of muscles in NHC (P < 0.001). CONCLUSION: The amount of TGF-ß1 was higher in HC fluid than in non-communicating. To investigate the role of cytokine in the closure of PV, further studies will be required.

Burn wound healing with injection of adipose-derived stem cells: a mouse model study.

Stem cells have shown promise with regard to the healing process of burn wounds. However, donor sites for these cells are still under investigation. The aim of this study is to review the efficacy of adipose tissue-derived stem cells (ADSCs) in accelerating wound healing of third degree burns in a mouse model. To this end, forty healthy male inbred Balb/c mice were selected and set up as an experimental model for third degree burn wounds. They were randomly divided into 3 equally sized groups: the ADSCs group, the mechanically prepared adipose tissue group, and the control group. The wounds were examined daily until the mice were sacrificed for tissue sampling in the 3(rd) week. Our results showed that wound surface area and eschar thickness were smaller in the ADSCs group throughout the study period, although there was no significant difference between the groups for decreasing values of wound area characteristics. In terms of wound healing parameters, lymphocyte and macrophage cell counts were larger in the ADSCs group compared to the other groups. Fibroplasia, collagen synthesis and remodeling were more aberrant in this group. However, there was no statistically significant difference in either of these observed differences (p>0.05). Although enzymatically prepared ADSCs seem a potential treatment in wound healing, our study of a mouse model burn wound revealed no significant improvement in using this option.

Les cellules souches se sont révélées prometteuses en ce qui concerne le processus de cicatrisation des plaies de brûlures. Cependant, les sites donneurs de ces cellules sont encore sous enquête. L'objectif de cette étude est d'examiner l'efficacité des tissus adipeux de cellules souches dérivées pour accélérer la cicatrisation des plaies de brûlures du troisième degré dans un modèle de souris. À cette fin, quarante souris mâles consanguines sains de la race Balb/c ont été sélectionnées et mis en place comme un modèle expérimental. Elles ont été réparties au hasard en trois groupes de taille égale : le groupe de tissu adipeux de cellules souches dérivées, le groupe de tissu adipeux mécaniquement préparé, et le groupe de contrôle. Les plaies ont été examinées tous les jours jusqu'à ce que les souris ont été sacrifiées pour prélever des tissus dans la troisième semaine. Nos résultats ont montré que la zone de surface de la plaie et l'épaisseur de l'escarre étaient moins dans le groupe de tissu adipeux de cellules souches dérivées tout au long de la période de l'étude, mais il n'y avait pas de différence significative entre les groupes pour diminuer les valeurs des caractéristiques de la surface de la plaie. En termes de paramètres de la cicatrisation, de lymphocytes et de macrophages comptages de cellules sont plus grandes dans le groupe de tissu adipeux de cellules souches dérivées par rapport aux deux autres groupes. La fibroplasie, la synthèse du collagène et le remodelage étaient plus aberrant dans ce groupe. Cependant, il n'y avait pas de différence statistiquement significative dans les différences observées (p> 0,05). Bien que le tissu adipeux de cellules souches dérivées et cela préparé enzymatiquement semblent un traitement potentiel dans la cicatrisation des plaies, notre étude d'un modèle de souris n'a révélé aucune amélioration significative dans l'utilisation de cette option.

Computational modelling and analysis of mechanical conditions on cell locomotion and cell-cell interaction.

Between other parameters, cell migration is partially guided by the mechanical properties of its substrate. Although many experimental works have been developed to understand the effect of substrate mechanical properties on cell migration, accurate 3D cell locomotion models have not been presented yet. In this paper, we present a novel 3D model for cells migration. In the presented model, we assume that a cell follows two main processes: in the first process, it senses its interface with the substrate to determine the migration direction and in the second process, it exerts subsequent forces to move. In the presented model, cell traction forces are considered to depend on cell internal deformation during the sensing step. A random protrusion force is also considered which may change cell migration direction and/or speed. The presented model was applied for many cases of migration of the cells. The obtained results show high agreement with the available experimental and numerical data.

Cell migration and cell-cell interaction in the presence of mechano-chemo-thermotaxis.

Although there are several computational models that explain the trajectory that cells take during migration, till now little attention has been paid to the integration of the cell migration in a multi-signaling system. With that aim, a generalized model of cell migration and cell-cell interaction under multisignal environments is presented herein. In this work we investigate the spatio-temporal cell-cell interaction problem induced by mechano-chemo-thermotactic cues. It is assumed that formation of a new focal adhesion generates traction forces proportional to the stresses transmitted by the cell to the extracellular matrix. The cell velocity and polarization direction are calculated based on the equilibrium of the effective forces associated to cell motility. It is also assumed that, in addition to mechanotaxis signals, chemotactic and thermotactic cues control the direction of the resultant traction force. This model enables predicting the trajectory of migrating cells as well as the spatial and temporal distributions of the net traction force and cell velocity. Results indicate that the tendency of the cells is firstly to reach each other and then migrate towards an imaginary equilibrium plane located near the source of the signal. The position of this plane is sensitive to the gradient slope and the corresponding efficient factors. The cells come into contact and separate several times during migration. Adding other cues to the substrate (such as chemotaxis and/or thermotaxis) delays that primary contact. Moreover, in all states, the average local velocity and the net traction force of the cells decrease while the cells approach the cues source. Our findings are qualitatively consistent with experimental observations reported in the related literature.

Dynamic iso-resistive trunk extension simulation: contributions of the intrinsic and reflexive mechanisms to spinal stability.

The effects of external resistance on the recruitment of trunk muscles and the role of intrinsic and reflexive mechanisms to ensure the spinal stability are significant issues in spinal biomechanics. A computational model of spine under the control of 48 anatomically oriented muscle actions was used to simulate iso-resistive trunk movements. Neural excitation of muscles was attained based on inverse dynamics approach along with the stability-based optimization. The effect of muscle spindle reflex response on the trunk movement stability was evaluated upon the application of a perturbation moment. In this study, the trunk extension movement at various resistance levels while extending from 60 degrees flexion to the upright posture was investigated. Incorporation of the stability condition as an additional constraint in the optimization algorithm increased antagonistic activities for all resistance levels demonstrating that the co-activation caused an increase in the intrinsic stiffness of the spine and its stability in a feed-forward manner. During the acceleration phase of the movement, extensors activity increased while flexors activity decreased in response to the higher resistance. The co-activation ratio noticed in the braking phase of the movement increased with higher resistance. In presence of a 30 Nm flexion perturbation moment, reflexive feed-back noticeably decreased the induced deviation of the velocity and position profiles from the desired ones at all resistance levels. The stability-generated co-activation decreased the reflexive response of muscle spindles to the perturbation demonstrating that both intrinsic and reflexive mechanisms contribute to the trunk stability. The rise in muscle co-activation can ameliorate the corruption of afferent neural sensory system at the expense of higher loading of the spine.