Combustion Synthesis of Porous TiC/Ti Composite by a Self-Propagating Mode

Porous titanium carbide (TiC) and TiC/Ti composites were synthesized by self-propagating high-temperature synthesis (SHS). Titanium and carbon powders were blended by various Ti/C blending ratios. The heat of reaction between titanium and carbon was high enough to induce the self-sustaining reaction of TiC formation on condition that some processing parameters (Ti/C ratio and porosity of the precursor) were appropriately selected. When the Ti/C blending ratio was high, the excess amount of titanium absorbed the heat of reaction. Consequently, the heated zone was not heated up to the ignition temperature. On the other hand, when the Ti/C ratio was low, high thermal conductivity of the precursor prevented an ignition of the heated side of precursors. The pore morphology was controlled by changing the Ti/C ratio and the preheat temperature.     

Biological activity of extracellular matrix‐associated BMP‐2

The critical requirement for matrix‐associated bone morphogenetic proteins (BMPs) during induction of bone formation in vivo has long been recognized. However, the role of extracellular matrix (ECM) physisorbed BMPs in inducing the differentiation of resident mesenchymal stem cells into osteoblasts has been ill‐defined. We therefore used BMP‐responsive C2C12s to study the biological activity of collagen type I physisorbed BMP‐2. Fibrillar collagen type I scaffolds were loaded with 75 ng BMP‐2/µg collagen. Under cell culture conditions, 40% of loaded ¹²⁵I‐labelled BMP‐2 was released within 24 h, whereas the remaining BMP‐2 was stably physisorbed for > 7 days. Using these systems suggested that physisorbed BMP‐2 is more active than diffusible BMP‐2. Thus, the current clinical practice of immobilizing BMPs on collagen type I scaffolds not only prolongs local delivery of the morphogen but could also enhance biological activity at the cellular level. Copyright © 2009 John Wiley & Sons, Ltd.     

Restoring axonal localization and transport of transmembrane receptors to promote repair within the injured CNS:a critical step in CNS regeneration

Each neuronal subtype is distinct in how it develops, responds to environmental cues, and whether it is capable of mounting a regenerative response following injury. Although the adult central nervous system (CNS) does not regenerate, several experimental interventions have been trialled with successful albeit lim-ited instances of axonal repair. We highlight here some of these approaches including extracellular matrix (ECM) modiifcation, cellular gratfing, gene therapy-induced replacement of proteins, as well as application of biomaterials. We also review the recent report demonstrating the failure of axonal localization and trans-port of growth-promoting receptors within certain classes of mature neurons. More speciifcally, we discuss an inability of integrin receptors to localize within the axonal compartment of mature motor neurons such as in the corticospinal and rubrospinal tracts, whereas in immature neurons of those pathways and in mature sensory tracts such as in the optic nerve and dorsal column pathways these receptors readily local-ize within axons. Furthermore we assert that this failure of axonal localization contributes to the intrinsic inability of axonal regeneration. We conclude by highlighting the necessity for both combined therapies as well as a targeted approach speciifc to both age and neuronal subtype will be required to induce substantial CNS repair.     

Short-Term Highly Intense Physiological Stress Causes an Increase in the Expression of Heat Shock Protein in Human Leukocytes

Extracellular heat shock protein with molecular weight of 70 kDa is a signal molecule of the immune system. It is secreted by the peripheral blood, liver and muscle cells in response to physiological, thermal, and mental stresses. The main goal of our study was to compare the levels of expression of heat shock protein (70 kDa) matrix ribonucleic acid in leukocytes and serum concentrations of the protein before and after physiological stress. In order to solve this problem, we developed enzyme immunoassay of serum heat shock (70 kDa) protein concentration and a method for evaluating the expression of matrix ribonucleic acid of this protein in leukocytes by the real time PCR. The concentration of 70 kDa heat shock protein in the serum increased 1.7 times as a result of even a short-term highly intense physiological stress, while the expression of its matrix ribonucleic acid in leukocytes increased 1.5 times. The individual features determine the response to physiological stress. Probable sources of 70 kDa heat shock protein are discussed. Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 147, No. 3, pp. 335–340, March, 2009     

Oleic acid modulation of the immune response in wound healing: A new approach for skin repair

Injury triggers inflammatory responses and tissue repair. Several treatments are currently in use to accelerate healing; however, more efficient formulations are still needed for specific injuries. Since unsaturated fatty acids modulate immune responses, we aimed to evaluate their therapeutic effects on wound healing. Skin wounds were induced in BALB/c mice and treated for 5 days with n-3, n-9 fatty acids or vehicle (control). n-9 treated mice presented smaller wounds than control and n-3 at 120 h post-surgery (p.s.). Collagen III mRNA, TIMP1 and MMP9 were significantly elevated in n-9 group compared to n-3 or vehicle at 120 h p.s. Among the inflammatory mediators studied we found that IL-10, TNF-α and IL-17 were also higher in n-9 treated group compared to n-3 or vehicle at 120 h p.s. Interestingly, COX2 had decreased expression on wound tissue treated with n-9. Inflammatory infiltrate analysis revealed diminished frequency of CD4⁺, CD8⁺ and CD11b⁺ cells in n-9 wounds at 24 and 120 h p.s., which was not related to cell death, since in vitro apoptosis experiments did not show any cell damage after fatty acids administration. These results suggested that unsaturated fatty acids, specifically n-9, modulate the inflammation in the wound and enhance reparative response in vivo. n-9 may be a useful tool in the treatment of cutaneous wounds.     

Association between the – 1562 C/T MMP-9 polymorphism and cerebrovascular disease in a Polish population

Background and purposeMatrix metalloproteinase 9 (MMP-9) is an endopeptidase degrading extracellular matrix. There is growing evidence that changes in extracellular matrix play an important role in vascular pathology, especially in cardiovascular and cerebrovascular disease. Previous studies have demonstrated that MMP-9 activity is controlled by –1562 C/T polymorphism. Genotypes with T allele (CT, TT) have higher enzymatic activity. Thus, this polymorphism could be responsible for the higher risk for cerebrovascular disease and death. The aim of this study was to assess the significance of MMP-9 polymorphism as a risk factor for cerebrovascular disease in a Polish population.Material and methodsA total of 775 consecutive patients with a diagnosis of cerebrovascular disease (ischaemic stroke, intracerebral haemorrhage, subarachnoid haemorrhage) admitted to the Stroke Unit, Jagiellonian University, Krakow, Poland between 2000 and 2004 were studied and compared with 766 matched controls. The polymorphism was studied by polymerase chain reaction (PCR) and restricted enzyme digestion.ResultsAmong 418 patients with ischaemic stroke of various aetiologies and among 146 patients with primary intracerebral haemorrhage and 211 patients with subarachnoid haemorrhage due to ruptured intracranial aneurysm, statistical analysis did not show a significant difference between occurrence of CC, CT, TT genotypes or C and T alleles in patients with stroke of various aetiology compared with controls.ConclusionsWe found no association between the –1562 C/T MMP-9 polymorphism and ischaemic stroke, subarachnoid haemorrhage or spontaneous intracerebral haemorrhage in the studied Polish population.     

Functional morphology of the sound-generating labia in the syrinx of two songbird species

In songbirds, two sound sources inside the syrinx are used to produce the primary sound. Laterally positioned labia are passively set into vibration, thus interrupting a passing air stream. Together with subsyringeal pressure, the size and tension of the labia determine the spectral characteristics of the primary sound. Very little is known about how the histological composition and morphology of the labia affect their function as sound generators. Here we related the size and microstructure of the labia to their acoustic function in two songbird species with different acoustic characteristics, the white-crowned sparrow and zebra finch. Histological serial sections of the syrinx and different staining techniques were used to identify collagen, elastin and hyaluronan as extracellular matrix components. The distribution and orientation of elastic fibers indicated that the labia in white-crowned sparrows are multi-layered structures, whereas they are more uniformly structured in the zebra finch. Collagen and hyaluronan were evenly distributed in both species. A multi-layered composition could give rise to complex viscoelastic properties of each sound source. We also measured labia size. Variability was found along the dorso-ventral axis in both species. Lateral asymmetry was identified in some individuals but not consistently at the species level. Different size between the left and right sound sources could provide a morphological basis for the acoustic specialization of each sound generator, but only in some individuals. The inconsistency of its presence requires the investigation of alternative explanations, e.g. differences in viscoelastic properties of the labia of the left and right syrinx. Furthermore, we identified attachments of syringeal muscles to the labia as well as to bronchial half rings and suggest a mechanism for their biomechanical function.     

The effects of enamel matrix derivative on the proliferation and differentiation of human mesenchymal stem cells

Purpose: This study was designed to investigate the effect of enamel derivative matrix (EMD) on the proliferation, mineralization, and differentiation of human mesenchymal stem cells (hMSCs). Material and methods: For the proliferation assay, water‐soluble tetrazolium salt‐8 tests were carried out after culturing for 24 and 48 h. For the evaluation of mineralization, Alizarin red S (ARS) tests were performed after 21 days of culturing in an osteogenic medium. In order to investigate some of the bone‐related proteins, namely type I collagen (Col I A2), bone sialoprotein (BSP), and bone γ‐carboxyglutamate (Gla) protein (BGLAP, osteocalcin), real‐time polymerase chain reaction (RT‐PCR) tests were carried out after 2, 3, and 4 weeks of culturing, respectively. Results: The activity of proliferation and mineralization increased significantly depending on the concentration of EMD (P<0.05). In the control group, the expression of Col I A2 decreased, but EMD enhanced its expression over time and was correlated to the concentration. The amount of expression of BSP in this group increased over time, but EMD strikingly suppressed its expression in the fourth week. As well, the amount of expression of BGLAP increased as the culture duration lengthened in the control group. However, the expression of BGLAP was suppressed in the experimental group with EMD. Conclusion: Within the limits of this study, EMD enhanced the proliferation of hMSCs. After evaluation with ARS staining, EMD seemed to enhance mineralization, and the RT‐PCR test revealed that EMD promoted early‐stage osteoblast differentiation by enhancing Col I A2 expression, but exerted an inhibitory effect on the mineralization by lowering the gene expression of BSP and BGLAP. Mineralized nodules formed with EMD may be composed of substances other than normal bone. Because most of the organic matrix of bone is type I collagen, which acts as the mineralization site, bone or bone‐like mineralized mass might have been formed in spite of the different components of the non‐collagenous proteins. To cite this article:
Jue S‐S, Lee WY, Kwon Y‐D, Kim Y‐R, Pae A, Lee B. The effects of enamel matrix derivative on the proliferation and differentiation of human mesenchymal stem cells.
Clin. Oral Impl. Res. 21 , 2010; 741–746.
doi: 10.1111/j.1600‐0501.2009.01901.x     

CT volume/density ratio as the marker of ischaemic brain injury

Kurzepa J, Bielewicz J, Czekajska‐Chehab E, Kurzepa J, Bartosik‐Psujek H, Grabarska A, Stelmasiak Z. CT volume/density ratio as the marker of ischaemic brain injury.
Acta Neurol Scand: 2011: 123: 310–315.
© 2010 John Wiley & Sons A/S. Objectives – We believe that the CT volume/density ratio (VDR) of infarcted area reflects the degree of brain tissue damage during ischaemic stroke (IS). Patients and methods – Forty six patients with IS were prospectively enrolled into the study. CT scan was performed on days 1 and 10 of hospitalization. S100BB serum level, gelatinase activities (MMP‐2 and MMP‐9) and neurological examination (NIHSS) were performed on days 1, 5 and 10 of IS. After 3 months, 42 patients were examined by functional disability scales: Barthel index (BI) and modified Rankin scale (mRS). Results – The VDR of ischaemic focus correlated well with the average S100BB serum level, MMP‐9 serum activity and NIHSS score. The weak but statistically significant relationships were noticed between the VDR vs BI and mRS estimated 3 months after stroke. Conclusion – VDR reflects well the damage ratio of brain tissue during IS. In addition, the study underlines the relationship between VDR vs patients’ neurological status and disability after IS.