Biochemical and Histological Differences Between Costal and Articular Cartilages

Biologically, costal cartilage is an understudied tissue type and much is yet to be learned regarding underlying mechanisms related to form and function, and how these relate to disease states, specifically chest wall deformity. Chest wall deformities have a component of inheritance, implying underlying genetic causes; however the complexity of inheritance suggests multiple genetic components. At our Centre investigations were performed on gene expression of key select genes from costal cartilage removed at surgery of patients with chest wall deformity to show high expression of decorin, a key player in collagen fiber formation and growth. Also, the degree of tissue differentiation was investigated that was different to that of articular cartilage as measured by gene ratio. Ultrastructural aspects of costal cartilage were determined by scanning and atomic force microscopy to show the presence of ‘nanostraws’ and preliminary data of nanostraw strength by measuring Young’s modulus of individual nanostraws. Protein deposition of collagen type II, decorin, and biglycan suggest orchestration of fiber formation in the interterritorial matrix. Although no specific biological markers related to chest wall deformity have currently been identified, work from our Centre has identified potential areas of interest

Simulation and energy partition of the flow through Paso Galvarino, Chile

Paso Galvarino is a constriction in Seno Ventisquero, a tidally-energetic Chilean fjord. The pass is about 1500 m long and constricts in width by about 90 % near its sill, which has a depth of about 8 m. A laterally-averaged numerical model is compared to ADCP and backscatter observations of the hydraulic flow near the sill, during maximum flood, the slack tide after the flood, maximum ebb, and the slack tide after the ebb. The model is also used to examine how the energy flux into the fjord is partitioned in the region of the constriction. Energy is removed from the surface tide near the sill and is largely dissipated near the sill. The model predicts that the internal tide is unimportant and that energy transport by advection is much more important than that due to radiation. Advection is significant only near the sill, however, and a counteracting surface flux develops that suppresses the influence of the advection

Effects of Nanosecond Pulse Electric Fields on Cellular Elasticity

We investigated the effects of a single 60 nanosecond pulsed electric field (nsPEF) of low (15 kV/cm) and high (60 kV/cm) field strengths on cellular morphology and membrane elasticity in Jurkat cells using fluorescent microscopy and atomic force microscopy (AFM). We performed force displacement measurements on cells using AFM and calculated the Young\u27s modulus for membrane elasticity. Differential effects were observed depending upon pulsing conditions. We found that a single nsPEF of low field strength did not induce any apparent cytoskeletal breakdown and had minor morphological changes. Interestingly, force measurements and calculation of Young\u27s modulus showed a significant decrease in membrane elasticity. A single nsPEF of high field strength induced stark morphological changes due to disruption of the actin cytoskeleton and a marked decrease in elasticity likely caused by irreversible membrane damage. We suggest that the cellular morphology is mainly dependent on stabilization by the actin cytoskeleton, while the elasticity changes are partially dependent on the cytoskeletal integrity

Dielectric Characterization of Coastal Cartilage Chondrocytes

BACKGROUND: Chondrocytes respond to biomechanical and bioelectrochemical stimuli by secreting appropriate extracellular matrix proteins that enable the tissue to withstand the large forces it experiences. Although biomechanical aspects of cartilage are well described, little is known of the bioelectrochemical responses. The focus of this study is to identify bioelectrical characteristics of human costal cartilage cells using dielectric spectroscopy. METHODS: Dielectric spectroscopy allows non-invasive probing of biological cells. An in house computer program is developed to extract dielectric properties of human costal cartilage cells from raw cell suspension impedance data measured by a microfluidic device. The dielectric properties of chondrocytes are compared with other cell types in order to comparatively assess the electrical nature of chondrocytes. RESULTS: The results suggest that electrical cell membrane characteristics of chondrocyte cells are close to cardiomyoblast cells, cells known to possess an array of active ion channels. The blocking effect of the non-specific ion channel blocker gadolinium is tested on chondrocytes with a significant reduction in both membrane capacitance and conductance. CONCLUSIONS: We have utilized a microfluidic chamber to mimic biomechanical events through changes in bioelectrochemistry and described the dielectric properties of chondrocytes to be closer to cells derived from electrically excitably tissues. GENERAL SIGNIFICANCE: The study describes dielectric characterization of human costal chondrocyte cells using physical tools, where results and methodology can be used to identify potential anomalies in bioelectrochemical responses that may lead to cartilage disorders

Nanosecond Pulsed Electric Field Induced Cytoskeleton, Nuclear Membrane and Telomere Damage Adversely Impact Cell Survival

We investigated the effects of nanosecond pulsed electric fields (nsPEF) on three human cell lines and demonstrated cell shrinkage, breakdown of the cytoskeleton, nuclear membrane and chromosomal telomere damage. There was a differential response between cell types coinciding with cell survival. Jurkat cells showed cytoskeleton, nuclear membrane and telomere damage that severely impacted cell survival compared to two adherent cell lines. Interestingly, disruption of the actin cytoskeleton in adherent cells prior to nsPEF exposure significantly reduced cell survival. We conclude that nsPEF applications are able to induce damage to the cytoskeleton and nuclear membrane. Telomere sequences, regions that tether and stabilize DNA to the nuclear membrane, are severely compromised as measured by a pan-telomere probe. Internal pore formation following nsPEF applications has been described as a factor in induced cell death. Here we suggest that nsPEF induced physical changes to the cell in addition to pore formation need to be considered as an alternative method of cell death. We suggest nsPEF electrochemical induced depolymerization of actin filaments may account for cytoskeleton and nuclear membrane anomalies leading to sensitization

Presence and Localization of Pro-and Mature Forms of Biglycan and Decorin in Human Costal Cartilage Derived from Chest Wall Deformities

Costal cartilage is a type of hyaline cartilage that forms rod-like structures that connect the ribs to the sternum. The most common chest wall deformities, pectus excavatum and pectus carinatum involved efective costal cartilage resulting in sternal displacement. Costal cartilage is not widely studied leaving little insight into possible factors involved in the pathogenesis of these pectus deformities. This study focused on the presence and distribution of two important regulators of collagen fibrillogenesis and organization, biglycan and decorin. Immunohistochemical analysis of transverse cross sections of normal and deformed costal cartilage revealed that biglycan and decorin mainly localized in the territorial matrix except for prodecorin which was only found within chondrocytes. Western blot analysis of whole protein extracts demonstrated the presence of both pro and mature forms of biglycan and mature decorin in patients and controls. In normal costal cartilage of different ages, the mature form of decorin was absent in a fetal sample whereas mature biglycan was weakly expressed, suggestive that mature biglycan may play a role in early costal cartilage development. Further studies are needed to determine the functional differences between the pro- and mature forms of biglycan and decorin both in age and disease

Enhanced Killing Effect of Nanosecond Pulse Electric Fields on PANC1 and Jurkat Cell Lines in the Presence of Tween 80

We investigated the effects of nanosecond pulse electric fields (nsPEFs) on Jurkat and PANC1 cells, which are human carcinoma cell lines, in the presence of Tween 80 (T80) at a concentration of 0.18% and demonstarted an enhanced killing effect. We used two biological assays to determine cell viability after exposing cells to nsPEFs in the presence of T80 and observed a significant increase in the killing effect of nsPEFs. We did not see a toxic effect of T80 when cells were exposed to surfactant alone. However, we saw a synergistic effect when cells exposed to T80 were combined with the nsPEFs. Increasing the time of exposure for up to 8 h in T80 led to a significant decrease in cell viability when nsPEFs were applied to cells compared to control cells. We also observed cell type-specific swelling in the presence of T80. We suggest that T80 acts as an adjuvant in facilitating the effects of nsPEFs on the cell membrane; however, the limitations of the viability assays were addressed. We conclude that T80 may increase the fragility of the cell membrane, which makes it more susceptible to nsPEF-mediated killing