Porcine Costal Cartilage Research Articles

Novel "Z" Technique to Overcome Warping of Costal Cartilage.

Dorsal augmentation with costal cartilage is generally used for aesthetic rhinoplasty. However, the tendency of costal cartilage to warp may jeopardize the aesthetic outcome. The aim of this study was to describe a new "Z" technique to overcome the warping of costal cartilage after implantation and to evaluate the efficacy of this technique in vitro. A total of 31 pairs of porcine costal cartilage grafts (40 mm × 10 mm × 5 mm) were obtained and kept in Dulbecco's Modified Eagle Medium (Sigma-Aldrich, St. Louis, MO) to maintain cell viability. Paired grafts were obtained and randomly allocated for preparation by the accordion technique and the "Z" technique. Standardized photographs (obtained immediately after operation and at 4 weeks) were used for warping analysis. Biomechanical testing was performed to measure the graft's capacity to resist deformation by an external force. Cell viability of the grafts at 4 weeks was comparably good in the accordion group and the Z group (61.88% ± 4.47% vs 67.48% ± 7.03%, P = 0.55). Warping angle was comparable between the 2 groups (P > 0.01). The capacity to resist external force was significantly better in the Z group; the force needed to cause deformation was 3.98 ± 1.04 N in the Z group vs 1.61 ± 0.47 N in the accordion group in lateral view (P < 0.0001), and 1.33 ± 0.41 N vs 0.96 ± 0.24 N, respectively, in frontal view (P = 0.0013). The "Z" technique appears to be a simple and effective method to minimize the tendency of costal cartilage to warp after implantation.

Flaw sensitivity and tensile fatigue of a high-strength hydrogel

This work describes mechanical behavior of a high-strength hydrogel composite relative to costal cartilage. The materials are analyzed for monotonic ultimate tensile strength (UTS) with differing flaws that represent extreme differences in local stress concentration and distribution. Selected hydrogel and cartilage samples are investigated for fatigue analysis via cyclic loading. Synthetic hydrogel samples are more sensitive toward sharp cracks, while cartilage samples are more sensitive toward cylindrical holes in fatigue. This work represents a unique tensile fatigue approach in studying a high-strength soft material and porcine costal cartilage with and without extreme defects.

A Two-Stage Training Program for Auricular Framework Fabrication Practicing Using Three-Dimensional Printing Silicone Ribs and Porcine Costal Cartilage.

Background:The manufacture of cartilage framework is a key element in the success of total ear reconstruction. Appropriate training can improve cartilage curving and fabricating skills, which is especially helpful for the novice clinicians. Based on threedimensional printing silicone model and porcine rib cartilage, the authors have designed a 2-stage training program to improve skills and cosmetic cognition for ear reconstruction.Methods:The training program includes 2 successive stages. In the first stage, trainees completed observation of framework fabrication, design and sculpturing practice on silicone rib models. Porcine costal cartilages are used for fabrication in the second stage. After that, the framework was put in a latex glove connected with a suction to simulate the skin cover procedure in operation.Results:At the end of the training program, all trainees could fabricate an ear-shaped cartilage framework successfully. Their cosmetic cognitions of the ear have also improved.Conclusions:Based on three-dimensional printing silicone model and porcine rib cartilage, the authors have designed a 2-stage training program to improve trainee’s carving techniques and cosmetic cognition for ear reconstruction. The authors believe that this training program is helpful in training, practicing and teaching activities of framework fabrication in total ear reconstruction.

Ex Vivo Electromechanical Reshaping of Costal Cartilage in the New Zealand White Rabbit Model

Determine the effective electromechanical reshaping (EMR) parameters for shape change and cell viability in the ex vivo rabbit costal cartilage model. Ex vivo animal study combined with computer modeling to guide electrode placement and polarity selection. Rabbit costal cartilages were secured in a jig that approximated the shape of the rabbit auricle framework. Finite element modeling was used to select the initial electrode geometry, polarity, spacing, and estimate dosimetry parameters. Porcine costal cartilage was utilized to refine the selection of dosing parameters. Parametric analysis was performed to determine the effect of voltage and application time on tissue shape change. Next, rabbit rib cartilage was reshaped, varying voltage and application time to identify the lowest parameters to produce acceptable shape change mimicking native auricular cartilage. Acceptable qualitative shape change was determined on a five-point Likert scale analyzed using one-way general linear analysis of variance. Confocal microscopy with live/dead cell viability analysis determined the degree of injury and the distribution of live and dead cells. The minimum acceptable deformation of rabbit costal cartilage was found at 4 V-3 minutes. Viability analysis of cartilage reshaped at 4 V-3 minutes demonstrates cell injury extending 2 mm away from each electrode with viable cells found between the electrodes. The EMR parameters of 4 V-3 minutes demonstrates appropriate shape change producing grafts that resemble the native auricle and contains the viable cells adequate for clinical evaluation. The rabbit auricular reconstruction model using EMR is a feasible one.

Electromechanical reshaping of costal cartilage grafts: A new surgical treatment modality

Needle electrode-based electromechanical reshaping (EMR) is a novel, ultra-low-cost nascent surgical technology to reshape cartilage with low morbidity. EMR uses direct current to induce mechanical relaxation in cartilage that is first deformed into a required geometry, which in turn leads to permanent shape change. The objective of this study was to determine the effect of EMR voltage and time on the shape change of costal cartilage grafts. EMR of ex vivo porcine costal cartilage. Graft specimens obtained from the central core of porcine costal cartilage were bent at a 90-degree angle with a custom jig and then reshaped via EMR. The effects of voltage (3-7 V) and application time (1-5 minutes) on the amount of shape change were systematically examined. Bend angles were analyzed using analysis of variance and paired t tests to determine significant reshaping times at each voltage setting. There is a threshold for voltage and time above which the retention of bend angle is statistically significant in treated specimens compared to the control (P < .05). Above the threshold of 3 V, shape retention initially increased with application time for all voltages tested and was then observed to reach a plateau. Shape retention was noted to be greatest at 6 V without a rise in temperature. EMR provides a novel method to bend and shape costal cartilage grafts for use in facial plastic surgery. A low voltage can reshape cartilage grafts within several minutes and without the heat generation. This study demonstrates the feasibility of EMR and brings this minimally invasive procedure closer to clinical implementation.

Laser reshaping of costal cartilage for transplantation

Laser reshaping of cartilage is a new effective and safe technique for correction of nasal septum and ear deformities. Costal cartilage is a most suitable natural material for transplantation. The problem is to obtain stable proper shape of cartilage implants. The objective of this article is to study reshaping of porcine costal cartilage for larynx stenosis surgery using Erbium glass fiber laser. Porcine cartilage plates 3 mm in thickness were mechanically curved and irradiated (1) on one side (stretched or compressed) and (2) on both sides with different sequence. Irradiation was performed using a 1.56 µm laser with power varied from 1 to 2.5 W, exposure time from 5 to 20 seconds, spot diameter of 2.5 mm, pulse duration of 500 milliseconds, pulse repetition rate of 1.4 Hz. For each laser setting, stable curvature radius was measured during 24 hours after the experiment. Irradiated samples were analyzed by means of differential scanning calorimerty (DSC) to reveal the collagen denaturation degree. The optimum laser setting for stable reshaping of costal cartilage without visual thermal damage of cartilage matrix was established: laser power of 2.2 W, exposure time of 6 seconds. Nonlinear thermomechanical behavior of cartilage in the course of its laser reshaping is experimentally revealed. The influence of irradiation sequence on the curvature radius of cartilage implant is found for the first time. It is shown that (1) it is possible to use laser reshaping technique for making stable proper shape of costal cartilage, and (2) primary irradiation of compressed side followed with an irradiation of stretched side is more effective than reverse sequence of laser treatment. DSC analysis showed that thermal effect of irradiated specimens (2.58-3.79 J/g) was slightly lower that that for intact cartilage specimens and considerably lower than that for denaturation of collagen (65 ± 5 J/g). It is possible to use laser reshaping technique for preparation of stable cartilage implants. Nonlinear thermomechanical behavior of cartilage is experimentally revealed. The influence of irradiation sequence on curvature radius of cartilage grafts is established for the first time.

Stabilization of Costal Cartilage Graft Warping Using Infrared Laser Irradiation in a Porcine Model

To develop a method to rapidly stabilize the shape change process in peripheral slices of costal cartilage by using infrared laser irradiation in a porcine model. Forty peripheral porcine costal cartilage specimens (40 × 10 × 2 mm) were harvested. Thirty of these specimens were immediately irradiated with an Nd:YAG laser (λ = 1.32 μm; spot size, 2-mm diameter) using 1 of 3 exposure treatments: 6 W, 2 seconds, and 4 spots; 8 W, 3 seconds, and 4 spots; or 6 W, 2 seconds, and 8 spots. Ten control specimens were only immersed in 0.9% saline solution. Angle of curvature was measured from photographs taken at 0 minutes, immediately after irradiation, and at 30 minutes, 1 hour, 5 hours, and 24 hours. Infrared imaging was used to measure surface temperatures during irradiation. Cell viability after irradiation was determined using a live/dead assay in conjunction with fluorescent confocal microscopy. Compared with the untreated controls, the irradiated grafts underwent accelerated shape change within the first 30 minutes to reach a stable geometry. Thereafter, irradiated grafts underwent little or no shape change, whereas the control group exhibited significant change in curvature from 30 minutes to 24 hours (P < .001). The average peak irradiated spot temperatures ranged from 76°C to 82°C. Cell viability measurements at the laser spot sites demonstrated a hemispherically shaped region of dead cells with a depth of 0.8 to 1.2 mm and a surface diameter of 1.9 to 2.7 mm. Laser irradiation of peripheral costal cartilage slices provides an effective method for rapidly stabilizing acute shape change by accelerating the warping process. The temperature elevations necessary to achieve this are spatially limited and well within the limits of tolerable tissue injury.

Numerical analysis of costal cartilage warping after laser modification

Grafts obtained from peripheral regions of costal cartilage have an inherent tendency to warp over time. Laser irradiation provides a potential method to control the warping process, thus yielding stable grafts for facial reconstructive surgery. In our current study, we propose a simple and well-fitting model that numerically describes the degree of warping of laser irradiated costal cartilage grafts. Using a Nd:YAG laser (λ=1.32μm) at various exposure settings, grafts harvested from the peripheral regions of porcine costal cartilage were irradiated. The resulting graft geometry was objectively fitted to a curve using a quadratic regression model. The coefficient of determination (R 2 ) demonstrated a very strong fit for all grafts modeled. A quadratic regression is simple to perform and results in a single numerical value that appropriately describes the degree of cartilage warping. Our proposed model is valuable in assessing the effect of laser irradiation on the warping process of costal cartilage.

A fiber reinforced poroelastic model of nanoindentation of porcine costal cartilage: A combined experimental and finite element approach

Nanoindentation has shown promise as a mechanical characterization tool for orthopaedic biomaterials since it can probe the properties of small, heterogeneous, irregularly shaped tissue volumes in physiological environments. However, the majority of nanoindentation analyses have been limited to the determination of linear elastic and viscoelastic properties. Since biomaterials possess complex nonlinear, hydrated, time-dependent constitutive behavior, the objective of the present study is to explore the ability of nanoindentation to determine physiologically relevant material properties using a fibril reinforced poroelastic (FRPE) model. A further goal is to ascertain the sensitivity of nanoindentation load–displacement curves to different FRPE parameters, including the elastic properties of the nonfibrillar matrix, the composition and distribution of fibers, and nonlinearity in the fluid permeability. Porcine costal cartilage specimens are experimentally tested with nanoindentation load relaxation experiments at two different loading depths and loading rates. The FRPE material properties are extracted from comparisons to finite element simulations. The study demonstrates the behavior of the model in nanoindentation is distinct from bulk indentation; the static response of the nanoindentation is determined almost exclusively by the elastic properties of the nonfibrillar matrix and the volume fraction of fibers, while the transient response is dominated by the fluid permeability of the tissue. The FRPE model can accurately describe the time-dependent mechanical behavior of costal cartilage in nanoindentation, with good agreement between experimental and numerical curve fits ( R 2 = 0.98 ± 0.01 ) at multiple indentation depths and indentation rates.

Effect of different solvents and crosslinkers on cytocompatibility of Type II collagen scaffolds for chondrocyte seeding.

Type II collagen extracted from porcine costal cartilage was evaluated as scaffolds for cartilage tissue engineering. Chemical crosslinkers were employed to improve the mechanical properties and the resistance toward degradation. Films and porous scaffolds were prepared from collagen solutions dissolved in 3% acetic acid (designated A) or in deionized water (designated W) and crosslinked by an epoxy (designated E) or by a carbodiimide (designated C). Immortalized rat chondrocytes and rabbit chondrocytes were used to assess cytocompatibility of crosslinked collagen matrices. Cell adhesion rate onto the films made by different preparations ranked in the order of WE > or = WC > AC > or = AE. Cell proliferation ranked in the order of AC > WC > AE > or = WE. Cells maintained round morphology only on AC and WC films. In 3-D seeding, AC scaffolds also were found to be the most cytocompatible. WC scaffolds, however, had better dimensional stability. It was concluded that Type II collagen scaffolds, when prepared by using deionized water as the solvent and carbodiimide as the crosslinker, could promote chondrocyte growth and matrix production.

Raised Somatomedin Activity in the Serum of Young Boys with Perthes?? Disease Revealed by Bioassay

This paper reports a study of the serum somatomedin activity in 67 boys with Perthes' disease and in 43 control boys aged three to 11 years. It was undertaken to evaluate some abnormalities of growth in children with Perthes' disease that have been previously reported. A brief account is given of knowledge relating to somatomedins in postnatal and fetal life. Serum somatomedin activity was measured using a bioassay based on the principle that somatomedins stimulate the synthesis of both DNA and proteoglycans in porcine costal cartilage. In control boys, the serum somatomedin activity increased with age, which is consistent with previous reports for normal children. In affected boys, the normal increase in serum somatomedin activity with age did not occur. The somatomedin activity in affected boys is higher than in control boys at three to five years but not at six to 11 years of age. Findings support the hypothesis that some children with Perthes' disease have an abnormality of the growth hormone-dependent somatomedins. The serum findings together with those of both skeletal age delay and impaired skeletal growth distally in the limbs are consistent with the view that the general disorder of some children with Perthes' disease results from an imbalance in mechanisms that determine the postnatal transition from the "fetal" to the "basic" component of the normal human growth curve.

Isolation and partial characterization of six somatomedin-like peptides from human plasma Cohn fraction IV.

Six somatomedin-like peptides were purified from human plasma Cohn fraction IV by a six-step procedure which included ethanol precipitation, reversed-phase extraction, gel filtration, chromatofocusing and reversed-phase high pressure liquid chromatography (HPLC). Purification was monitored with a competitive protein binding assay using a crude preparations of somatomedin carrier protein. The peptides isolated were homogeneous by reversed-phase HPLC and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Their apparent isoelectric points determined by chromatofocusing were 9.2 (Sm I), (Sm II), 8.2 (Sm III), 6.7 (Sm IV), 6.3 (Sm V), and 6.15 (Sm VI). SDS-PAGE under reducing conditions revealed that they are composed of a single peptide chain with apparent molecular weights of 6800 for Sm I, II and IV and 6400 for Sm III, V, and VI. They were equally potent in the porcine costal cartilage in vitro bioassay. The basic peptides (Sm I-III) were significantly more active in radioimmunoassays for somatomedin C (SmC) and insulin-like growth factor I C-peptide (IGF-I (30 - 41], while only the slightly acidic peptides were active in a radioimmunoassay for insulin-like growth factor II C-peptide (IGF-II (33-40]. When receptor binding was tested with human placental cell membranes and Sm III as tracer, the basic peptides were significantly more potent than Sm IV-VI. With rat liver cell membranes and Sm V as tracer the slightly acidic peptides were more potent. These findings suggest 1) that human plasma may contain other somatomedin-like peptides besides the major components IGF-I/SmC and IGF-II, and 2) that the basic peptides are structurally related to IGF-I/SmC and the slightly acidic peptides are related to IGF-II.

Changes in the concentration of somatomedin-like activity in amniotic fluid and maternal plasma from rhesus monkeys during the last third of gestation.

Somatomedin-like activity (SLA) was measured in serial samples of amniotic fluid and maternal plasma from Rhesus monkeys (Macaca mulatta) using the porcine costal cartilage disc bioassay. Samples of both amniotic fluid and maternal plasma gave dose response curves which were parallel to the human plasma standard. Concentrations of SLA were consistently lower in amniotic fluid (0.42 +/- 0.02, mean +/- S.E.M., units/ml, n = 33) than in maternal plasma (0.60 +/- 0.03 units/ml, n = 31). No significant changes in concentrations of SLA with gestational age were found during the period studied (90-170 days of pregnancy). The presence of SLA in amniotic fluid is consistent with the possibility that somatomedin plays a role in the control of foetal or placental growth in the primate.

Somatomedin-like activity in cattle: the effect of breed, lactation and time of day.

Somatomedin-like activity (SLA) was measured in plasma samples from cattle using the porcine costal cartilage disk bioassay. In 40-day-old pre-ruminant bull calves, SLA was highest in the plasma of eight Friesians (mean potency 0.97 +/- 0.06 (S.E.M.) units/ml), lowest in five Aberdeen Angus x Friesians (0.78 +/- P < 0.05) and intermediate in six Hereford x Friesians (9.89 +/- 0.09). Plasma levels of SLA were significantly (P < 0.01) lower in eight lactating Friesian (high-yielding) cows (0.53 +/- 0.04) than in five dry cows (0.76 +/- 0.06). Levels of SLA in the plasma of a further eight lactating Hereford x Friesian (low-yielding) cows (0.76 +/- 0.07) were similar to the levels in the plasma of the five dry dairy cows. Large diurnal changes in plasma SLA occurred in lactating Hereford x Friesian and Friesian heifers. In three Hereford x Friesian heifers plasma levels of SLA were lowest at 19.00 h (0.39 +/- 0.07) and highest at 03.00 h (0.77 +/- 0.08). A similar pattern was present in plasma samples from three Friesian heifers; the lowest levels of SLA being at 21.00 h (0.37 +/- 0.07) and the highest at 05.00 h (0.61 +/- 0.13). Throughout the period of 24 h the overall mean levels of SLA were significantly (P < 0.01) higher in the plasma samples from the three Hereford x Friesian heifers (0.6 +/- 0.01) than in the samples from the three Friesian heifers (0.49 +/- 0.02 units/ml).

Somatomedin activity in synovial fluid from patients with joint diseases.

The somatomedin activity in synovial fluids from 50 patients with a variety of joint diseases has been studied and compared with the activity in each of the patient's own serum and a standard reference serum (SRS). The porcine costal cartilage bioassay of Van den Brande and Du Caju (1974a) has been used with the isotopes 3H-thymidine and 35S-sulphate. Synovial fluids from most patients with post-traumatic and post-operative effusions, osteoarthritis and arthritis associated with psoriasis, Reiter's disease, and ankylosing spondylitis stimulated the synthesis of DNA and proteoglycans in cartilage. Synovial fluids from patients with rheumatoid arthritis either had impaired capacity to stimulate DNA synthesis, or they inhibited it; a similar, but less evident pattern was observed for proteoglycan synthesis. Some synovial fluids from patients with miscellaneous synovitides stimulated, while others inhibited cartilage metabolism. It is concluded that the synovial fluid from patients with rheumatoid arthritis and from some patients with miscellaneous synovitides contained an inhibitor(s) to DNA and possibly proteoglycan synthesis. The sera from nearly all the patients stimulated both DNA and proteoglycan synthesis, but the somatomedin potency ratios for serum in terms of SRS were generally less than 1.0. There was a significant inverse correlation between the serum somatomedin potency ratio and the age of the patient.

A rapid simplified bioassay for somatomedin.

A simplified, more rapid bioassay for the estimation of somatomedin activity, based on the porcine costal cartilage bioassay, is described. A micro-scale system based on the porcine costal cartilage assay is also described. These assay systems showed no decrease in sensitivity or precision, compared with other methods, as a result of the modifications. The assays have been used for routine hospital laboratory determinations, for the estimation of somatomedin activity in normal adolescent children of both sexes and in clinical studies of scoliotic, acromegalic and hypopituitary patients.

Somatomedin activity in synovial fluid.

Abnormalities of synovial fluid, as a lubricant and nutrient, may have relevance to the causation of certain articular diseases. The somatomedin activity in normal synovial fluid obtained from the knee joint of the ox has been studied and compared with the activity in serum from the same animal. The porcine costal cartilage bioassay of Van den Brande and Du Caju (1974) has been used with the isotopes 35S-sulphate and 3H-thymidine. The mean potency ratio of ox synovial fluid in terms of ox serum for 35S-sulphate incorporation was 0-28 (range 0-19-0-47) and for 3H-thymidine incorporation 0-35 (range 0-21-0-63). A significant correlation was found between the somatomedin activity (as measured by 35S-sulphate incorporation) and the total protein and albumin concentrations in the ox synovial fluids and the ox sera, but there was no significant relationship between the somatomedin potency ratios and the globulin concentrations. The possible relevance of these findings to injury and disease in synovial joint is discussed.

OBSERVATIONS ON A SOMATOMEDIN (SM) INHIBITOR IN SEVERELY MALNOURISHED CHILDREN

In 13 patients with marasmus or kwashiorkor, plasma SM was measured using the porcine costal cartilage assay. Non-parallelism (N.P.) due to a shallow slope prevented quantitation in many samples. Results: SM-distriSution: on admission ≤ .20:5; .20 < x < .50:3; .50 < x < .80:2, N.P.:3. After 4-6 weeks of treatment: low : 6, normal: 1, N.P. : 3 (3 had died, all with initial SM < .20). After 8-10 weeks: low: 3, normal or high : 3, N.P. : 3 (one more child had died). Mixing plasma from 3 untreated patients with the standard lowered its apparent potency with 35, 67 and 0% resp. Heating plasma after acidification increased its potency relative to a standard control from < .12 to .65. Concl.: In severe and chronic malnutrition heat-labile SM-inhibiting material is present in plasma, initially persisting during treatment. This may contribute to the problems in reverting these children from a katabolic to an anabolic state.

Somatomedin stimulation of sulfate incorporation in porcine costal cartilage discs.

Uniform discs punched from slices of porcine costal cartilage were used to measure somatomedin stimulation of sulfate incorporation under various experimental conditions. Basal incorporation of sulfate was relatively constant in discs from different locations along a cartilage segment and stimulation (40% normal serum compared to buffer) was comparable in discs from different positions within the cartilage slices. A simple Tris-amino acid buffer allowed greater stimulation than the more highly supplemented Ham's F-10 or Dulbecco Eagle's buffers. Porcine cartilage from younger animals was more sensitive to serum stimulation (fetal > 6–9 months old > mature). Increased disc weight was significantly correlated with decreased serum stimulation using cartilage from marketable animals (6–9 months old). A maximum dry weight of 1.8 mg/disc (1 × 2.5 mm) allowed consistently good somatomedin assays. Incorporation of sulfate by discs obtained from 6–9-month-old pigs fell with increasing incubation time. The fall was...

An improved technique for measuring somatomedin activity in vitro.

ABSTRACT A method for measuring somatomedin activity in vitro is described. Porcine costal cartilage fragments are prepared and incubated using a special dissection and incubation apparatus. The schedule consists of a 24 h pre-incubation, 46 h of incubation with the test substance and 3 h of post-incubation in a medium containing both 35S-Na2SO4 and 3H-thymidine. The average index of precision is 0.15 for 35S-uptake and 0.19 for 3H-thymidine. Although the assay is less sensitive than the hypophysectomized rat assay, it yields a considerable increase in precision, it is far less laborious to perform and is not so expensive.