Collagen

The epithelium of the secondary palate from embryonic mice (12-14 days of gestation) was enzymatically separated from the palatal mesenchyme and was cultured in association with mesenchyme from the embryonic tongue, incisor, and salivary gland. The histological differentiation of the epithelium in each type of heterotypic recombination was always palatal. Tongue mesenchyme supported full histodifferentiation of the palatal epithelium, whereas incisor mesenchyme supported only a limited histodifferentiation in the epithelium. Salivary gland mesenchyme in direct combination with palatal epithelium influenced the epithelium to become organized into a system of ducts and acini typical of glandular morphogenesis; histodifferentiation of the epithelium, however, was palatal. Salivary gland mesenchyme grown in isolation did not undergo glandular morphogenesis.

For musculoskeletal tissues that transmit loads during movement, the interfaces between tissues are essential to minimizing injury. Therefore, the reproduction of functional interfaces within engineered musculoskeletal tissues is critical to the successful transfer of the technology to the clinic. The goal of this work was to rapidly engineer ligament equivalents in vitro that contained both the soft tissue sinew and a hard tissue bone mimetic. This goal was achieved using cast brushite (CaHPO 4 Á2H 2 O) anchors to mimic bone and a fibrin gel embedded with fibroblasts to create the sinew. The constructs formed within 7 days. Fourteen days after seeding, the interface between the brushite and sinew could withstand a stress of 9.51 AE 1.7 kPa before failure and the sinew reached a Young's modulus value of 0.16 AE 0.03 MPa. Treatment with ascorbic acid and proline increased the collagen content of the sinew (from 1.34% AE 0.2% to 8.34% AE 0.37%), strength of the interface (29.24 AE 6 kPa), and modulus of the sinew (2.69 AE 0.25 MPa). Adding transforming growth factor-b resulted in a further increase in collagen (11.25% AE 0.39%), interface strength (42 AE 8 kPa), and sinew modulus (5.46 AE 0.68 MPa). Both scanning electron and Raman microscopy suggested that the interface between the brushite and sinew mimics the in vivo tidemark at the enthesis. This work describes a major step toward the development of tissue-engineered ligaments for the repair of ligament ruptures in humans.

Nanotechnology has made great strides forward in the creation of new surfaces, new materials and new forms which also find application in the biomedical field. Traditional biomedical applications started benefiting from the use nanotechnology in an array of areas, such as biosensors, tissue engineering, controlled release systems, intelligent systems and nanocomposites used in implant design. In this manuscript a review of developments in these areas will be provided along with some applications from our laboratories.

Idiopathic pulmonary fibrosis (IPF) is thought to involve inflammatory infiltration of leukocytes, lung injury induced by reactive oxygen species (ROS), in particular superoxide anion, and fibrosis (collagen deposition). No treatment has been shown to improve definitively the prognosis for IPF patients. Superoxide dismutase (SOD) catalyzes the dismutation of superoxide anion to hydrogen peroxide, which is subsequently detoxified by catalase. Lecithinized SOD (PC-SOD) has overcome clinical limitations of SOD, including low tissue affinity and low stability in plasma. In this study, we examined the effect of PC-SOD on bleomycin-induced pulmonary fibrosis. Severity of the bleomycin-induced fibrosis in mice was assessed by various methods, including determination of hydroxyproline levels in lung tissue. Intravenous administration of PC-SOD suppressed the bleomycin-induced increase in the number of leukocytes in bronchoalveolar lavage fluid. Bleomycin-induced collagen deposition and incr...

Uninephrectomized rats drinking 1% sodium chloride were given aldosterone (Aldo, 0.75 gg/h, subcutaneous Is.c.I infusion), deoxycorticosterone (DOC, 20 mg/wk, s.c.), corticosterone (B, 2 mg/d, s.c.), or the antiglucocorticoid-antiprogestin RU486 (2 mg/d, s.c.) for 8 wk, and hemodynamic and tissue responses were compared with a non-steroid-treated control group. Aldo and DOC markedly increased systolic BP and caused considerable (40-50%) cardiac hypertrophy; B and RU486 caused neither hypertension nor cardiac hypertrophy. Measurements of ventricular cross-sectional areas showed hypertrophy due to an increase in mass of the left ventricle only. Cardiac hydroxyproline concentration was increased considerably by Aldo and DOC, to a lesser degree by RU486, and not by B. Aldo markedly elevated left ventricular interstitial collagen (2.5-fold vs control, P < 0.01 vs all groups); other steroid treatments also increased interstitial collagen over control (DOC X 1.8-, RU486 X 1.6-, B X 13-fold), with identical responses for right and left ventricles (r = 0.94). A different pattern of perivascular fibrosis was noted; DOC elevated perivascular collagen (2.1-fold vs control, P < 0.01 vs all other groups); RU486 raised levels 1.4-fold vs control, but neither Aldo nor B significantly affected perivascular collagen. These data are consistent with interstitial cardiac fibrosis reflecting type I (mineralocorticoid) receptor occupancy by administered Aldo or DOC, or by elevated endogenous B after type II (glucocorticoid) receptor blockade after RU486 administration; perivascular fibrosis may reflect a composite response after type I receptor agonist/type II glucocorticoid receptor antagonist occupancy. (J. Clin. Invest. 1994.93:2578-2583

Instability of the glenohumeral joint can be associated with anteroinferior capsulolabral rupture. To understand its static stabilizing effect better, the collagen fiber orientation of the inferior glenohumeral ligament (IGHL), a component of the anteroinferior capsulolabrum, was studied with a small angle light scattering technique. Three rectangular samples (approximately 11 ϫ 6 mm) were excised from the axillary pouch, one from the anterior band (AB) of the IGHL and one control sample from the long head of the biceps tendon of 7 cadaveric shoulders. The small angle light scattering technique scans the tissue with a heliumneon laser beam and quantifies the fiber alignment based on the resultant scattering pattern. The fiber orientation was quantified by an orientation index, defined as the angle within which 50% of the fibers lie. The axillary pouch had a random orientation, whereas the AB-IGHL was random with some regions of localized alignment. The percentage of tissue with an orientation index range of 25°to 45°was 23.2% Ϯ 8.5% and 29.0% Ϯ 13.1% for the axillary pouch and the AB-IGHL, respectively, whereas that for the long head of the biceps tendon was 61.6% Ϯ 15.2%. This suggests that the collagen fibers in the IGHL are not highly aligned and the anteroinferior capsulolabrum can be modeled as a continuous sheet. Moreover, a biomechanical evaluation of the anteroinferior capsulolabrum that investigates the possibility that the mechanical properties may be directionally independent should be conducted. (J Shoulder Elbow Surg 2003; 12:247-52.) The glenohumeral joint is the most commonly dislocated diarthroidal joint in the body, and after the initial episode, 85% to 90% of young persons have subsequent dislocation. 12 Whereas surgical repair lowers recurrence, redislocation rates are as high as 12% and 23% after open and arthroscopic surgical procedures, respectively. 29 Acute dislocation in human beings was often found to result in a Bankart lesion, 3,4,21 which includes rupture of the anteroinferior capsulolabrum. This is now known to include a lesion of the glenoid insertion site of the inferior glenohumeral ligament (IGHL), 14,18,25 the primary static restraint to anterior translation of the humeral head on the glenoid. Given that surgical repairs have focused on restoration of the anteroinferior capsulolabrum, 1,24 its anatomy has been meticulously studied. The collagen cross-links, collagen fibril diameter and density, amino acid composition, and elastic fibers have also been examined. 23 When compared with the capsule from unstable shoulders, the normal capsule consists of a greater number of cross-links and smaller fibril diameters. Further research has demonstrated that the anterior capsule is composed of areolar (loose connective) tissue. The anterior band (AB), axillary pouch, and posterior band (PB) of the IGHL have been identified, 20 and the ability of each component to resist forces along its long axes in the medial-tolateral direction was studied. 5,6,30 The AB-IGHL exhibits an increased thickness and superior mechanical properties compared with the other components of the capsule. 5 Recent research also demonstrated the importance of the capsular tissue between the AB-IGHL and PB-IGHL, the axillary pouch. 8,17 Significant forces were transmitted in the direction perpendicular to the long axis of the AB-IGHL. In an effort to understand the role of the anteroinferior capsulolabrum in resisting dislocation better, the orientation of the collagen fibers within each of the three regions of the IGHL has been qualitatively examined with polarized light microscopy. 10,20 O'Brien et al 20 found the axillary pouch to be less organized than either the AB-IGHL or the PB-IGHL and demonstrated a great deal of intermingling of the fibers. This finding indicated that the axillary pouch could resist forces other than those in the medial-to-

Quantitative ultrasound (QUS) of bone is a valuable tool in the assessment of postmenopausal osteoporosis. QUS and new markers of bone turnover have been poorly assessed in Cushing's syndrome, however. Twenty-five patients with Cushing's syndrome (20 women, 3 men; mean age + SEM: 38 + 2 years) were studied and compared with 35 age-and sexmatched control patients (mean age + SEM: 38 + 2 years). The following variables were measured in both groups: QUS parameters at the heel (BUA; SOS; Stiffness Index, SI); bone mineral density (BMD) at both the lumbar spine (LS) and femoral neck (FN) by dual-energy X-ray absorptiometry; and serum markers of bone turnover (osteocalcin, procollagen type I N-and Cterminal propeptides (PINP and PICP), bone alkaline phosphatase (BAP), procollagen type I C-terminal telopeptide (ICTP) and urinary type I collagen Ctelopepetide breakdown products (CTX)). Both BUA and SI were decreased in patients with Cushing's syndrome (p<0.01) but not SOS (p=0.08). BMD was also strongly decreased in Cushing's syndrome, at both the LS and FN (p<0.005). The two markers of bone turnover statistically significantly different between the two groups were osteocalcin (mean + SEM: 3.5 + 0.7 ng/ml (Cushing's syndrome) vs 6.4 + 0.5 ng/ml (controls, p<0.01)) and CTX (mean + SEM: 148.7 + 17.1 mg/mmol Cr (Cushing's syndrome) vs 220.8 + 22.9 mg/mmol Cr (controls), p<0.05). The areas under the receiver operating characteristic curve (AUC) were 0.72 (BUA), 0.73 (SI), 0.90 (BMD LS ), 0.81 (BMD FN ), 0.83 (osteocalcin) and 0.64 (CTX) respectively. AUC was significantly higher for BMD LS than for both BUA and SI (p<0.05). Conversely AUC was not statistically significantly different for BMD FN as compared with either BUA or SI. AUC was also higher for osteocalcin than for other markers of bone turnover. In conclusion, QUS of bone seems to be a relevant tool for assessing bone involvement in Cushing's syndrome. QUS does have a lower sensitivity compared with DXA, however, and the relevance of QUS cannot be ascertained until some longitudinal data are forthcoming. Except for CTX, the other new markers of bone turnover assessed in this study (PINP, PICP, BAP and ICTP) do not seem of interest in Cushing's syndrome.

Vocal fold paralysis (VFP) is the second most common congenital abnormality that affects the larynx. Unilateral cases may be asymptomatic or feature symptoms related to laryngeal incompetence, such as aspiration and dysphonia. Management has traditionally been conservative as a high percentage of these paralyses recover spontaneously. The literature is scant on the acute or chronic management of unilateral vocal fold paralysis related symptoms in children. We present a series of four children (age 21 days, 5 years, 5 years, and 18 years) with unilateral VFP paralysis treated with collagen (Cymmtera) augmentation for control of symptoms related to laryngeal incompetence. Two children (age 21 days and 5 years) were managed in the acute setting. Follow-up has ranged from 4 to 12 months, and all have maintained excellent outcomes. Vocal fold augmentation with collagen is an effective therapeutic option in the management of symptoms related to unilateral VFP and laryngeal incompetence. It decreases the risk of aspiration and improves vocal quality. Collagen augmentation can be used in the acute setting to decrease aspiration, possibly avoiding a tracheotomy or gastrostomy tube placement, or to augment patients with a tracheotomy who are still severely aspirating.

The antitumor efficacy as well as hematologic and pulmonary toxicity of Liblomycin, a new lipophilic analog of bleomycin, was evaluated in BDF1 mice. In comparison to bleomycin which was without any antitumor efficacy against P388 leukemia, a dose of 10 mg/kg Liblomycin administered on a daily schedule for 10 consecutive days resulted in a significant increase in animal survival (~ T/C of 190). This therapeutic dose and schedule of drug administration did not produce any evidence of pulmonary histopathologic injury; at a similar dose and schedule bleomycin resulted in greater than 40% consolidation of alveolar lung space. Mouse lung collagen synthesis measured as rate of [3H]hydroxyproline formation was increased almost 4-fold by bleomycin 7 days following a single maximally tolerated i.v. injection (133 mg/kg); in contrast, Liblomycin (60 mg/kg) did not significantly alter the rate of lung collagen synthesis compared to saline injected control animals. Lung function was assessed by whole body plethysmography. Bleomycin produced an increase in breathing rates above control values by day 15 following administration of drug at 10 mg/kg (dl -10). Mice treated with Liblomycin did not exhibit an increased rate of breathing. Liblomycin, in contrast to bleomycin, produced mild and transient leukopenia and thrombocytopenia suggesting that this toxicity will be a limiting one in future clinical trials. The only other toxicity noted in this study was the appearance after repeated intraperitoneal administration of Liblomycin of a hepatic collagenous fibrous capsule. The capsule formation resulted in an abnormal and grossly lobulated liver which was believed to have affected animal survival. Intravenous administration of Liblomycin, however, was not associated with any detectable hepatic injury.

The propeptides PICP and PINP are derived from the synthesis of type I collagen, a major matrix protein of bone and soft tissues. The aim of this cross-sectional study was to investigate their value as indicators of the aggressivity of breast cancer. Serum PINP, PICP, and total alkaline phosphatase were determined from 89 breast cancer patients. Forty had major bone and/or soft tissue metastases with an aggressive disease course: the progressive disease (PD) group. Forty-nine had either none or minor bone and/or soft tissue metastases with a stable clinical course: the stable disease group (SD). The mean value of PINP in the PD group was 7.2 times higher than that in the SD group (276 +/- 79 microg/l versus 38 +/- 3 microg/l, respectively; P = 0.005), whereas PICP mean value was only 1.7 times higher in the PD group (174 +/- 20 microg/l versus 100 +/- 5 microg/l; P = 0.001). The ratio of PICP to PINP was 1.02 +/- 0.07 in the PD group and 3.07 +/- 0.18 in the SD group (P &lt; 0.001)....

The effect of gamma irradiation therapy on the ultimate tensile strength (UTS) of enamel and dentin in relation to prism orientation, dentin tubule orientation, and location is unknown. It was hypothesized that tubule and prism orientation, location, and irradiation have an effect on the UTS of dental structures. Forty human third molars were used, half of which were subjected to 60 Gy of gamma irradiation, in daily increments of 2 Gy. The specimens were evaluated by microtensile testing. Results showed that irradiation treatment significantly decreased the UTS of coronal and radicular dentin and of enamel, regardless of tubule or prism orientation. With or without irradiation, enamel was significantly stronger when tested parallel to its prismatic orientation. Coronal and radicular dentin of non-irradiated specimens presented significantly higher UTS when tested perpendicularly to tubule orientation. However, when the teeth were irradiated, the influence of tubule orientation disappeared, demonstrating that irradiation is more harmful to organic components.

Background. Cell implantation into ischemic regions has recently been introduced as a novel strategy for therapeutic angiogenesis. Little is known, however, about the process of blood vessel regeneration, particularly that of the inferior vena cava (IVC). The indicators of normal angiogenesis are also unestablished.

In the present study, we tested the hypothesis of the indirect (via the sympathetic nervous system (SNS)) and direct (via AT1 receptors) contributions of Angiotensin II (Ang II) on the synthesis of collagen types I and III in the left ventricle (LV) in vivo. Sympathectomy and blockade of the Ang II receptor AT1 were performed alone or in combination in normotensive rats. The mRNA and protein synthesis of collagen types I and III were examined by Q-RT-PCR and immunoblotting in the LV. Collagen types I and III mRNA were decreased respectively by 53% and 22% after sympathectomy and only collagen type I mRNA was increased by 52% after AT1 receptor blockade. mRNA was not changed for collagen type I but was decreased by 25% for collagen type III after double treatment. Only collagen protein type III was decreased after sympathectomy by 12%, but collagen proteins were increased respectively for types I and III by 145% and 52% after AT1 receptor blockade and by 45% and 60% after double treatment. Deducted interpretations from our experimental approach suggest that Ang II stimulates indirectly (via SNS) and inhibits directly (via AT1 receptors) the collagen type I at transcriptional and protein levels. For collagen type III, it stimulates indirectly the transcription and inhibited directly the protein level. Therefore, the Ang II regulates collagen synthesis differently through indirect and direct pathways.

Determining arterial mechanical properties is important for understanding the work done by the heart and how it changes with cardiovascular disease. Ex vivo tests are necessary to apply various loads to the artery and obtain data to model and predict the behavior under any load. Most ex vivo tests are performed within 24 hours of dissection, so the tissue is still "alive". For large elastic arteries, however, the passive mechanical behavior is attributed mostly to the very stable proteins, elastin and collagen. If the testing equipment fails, is in use, or is located at another facility, it would be useful to store the vessels and postpone the tests until the equipment is available. The goal of this study is to determine the effects of storage time on the mechanical behavior of the common carotid artery from adult mice. Each artery was tested after storage for 1-28 days in physiologic saline at 4°C. There were no significant effects of storage time on the arterial diameter or force at each pressure, but there were significant effects on the stretch ratio and stress at each pressure. The significant effects on the stretch ratio and stress were due to decreases in the unloaded dimensions with storage time, when measured from cut arterial rings. When the unloaded dimensions were measured instead from histology sections, there were no significant changes with storage time. We conclude that histology sections yield a more consistent measurement of the unloaded dimensions and that there are no significant changes in the mechanical behavior of mouse carotid artery with storage up to 28 days.

The mouse antithrombotic assay represents a model of fatal pulmonary thromboembolism induced by intravenous injection of collagen and epinephrine. Mice were protected by low doses of two disintegrins, albolabrin (10 l.@/mouse) and eristostatin (0.6 pg/mouse), whereas high doses of a thrombin inhibitor and an inhibitor of von Willebrand Factor binding to glycoprotein Ib were not effective. Injection of collagen and epinephrine resulted in the drop of platelet count and accumulation of platelet aggregates in 'the lung that appears to be the immediate cause of death. Albolabrin or eristostatin administration did not prevent the decrease of platelet count. Injection of albolabrin resulted in the formation of smaller and reversible platelet aggregates in the lungs and decreased accumulation of SlCr-labeled platelets in the lung suggesting that this disintegrin decreases formation of platelet aggregates in viva We compared the effects of allbolabrin and eristostatin on platelet aggregation, tail bleeding time, and survival of challenged animals. Eristostatin was about 5 times more potent in inhibiting platelet aggregation in vitro than albolabrin and 38 times more potent than albolabrin in protecting animals from sudden death. Both disintegrins, at the same doses (0.6-5 ltglmouse), caused similar dose-dependent prolongation of the bleeding time; however, only eristostatin exerted a protective effect. In conclusion, a) the mouse antithrombotic assay is a suitable model to screen and to evaluate the potency of platelet fibrinogen receptor antagonists in vivo; b) the results of the antithrombotic assay correlate better with the inhibition of platelet aggregation in vitro than with the prolongation of bleeding time.

We report a study of the substratum and medium requirements for attachment and neurite outgrowth by cells of the pheochromocytoma-derived PC12 line. In attachment medium containing both Ca2+ and Mg2+, more than 50% of cells attached within 1 hr to petri dishes coated with native collagen Types I/III or II, native or denatured collagen Type IV, laminin, wheat germ agglutinin (WGA), or poly-L-lysine; attachment to dishes coated with nerve growth factor (NGF) was only about 20% and attachment to uncoated dishes or to dishes coated with fibronectin or gelatin was almost nil. Neither prior culturing in the presence of NGF nor addition of NGF to the attachment medium significantly affected the extent of attachment to collagen or laminin. With Ca2+ (1 mM) as the sole divalent cation, cells attached normally to WGA, polylysine, and NGF, but failed to attach to collagen or laminin. With Mg2+ (1 mM) as the only divalent cation, attachment to all substrata was about the same as in medium with ...

The vertebrate inner ear has been extensively studied as a model system of morphogenesis and differentiation. The interactions between epithelium and surrounding mesenchyme have not previously been studied directly, because an appropriate experimental system had not been established. Here we describe a mesenchyme-free culture system of E11.5 mouse otic vesicle which retains the ability for (1) formation of the cochlear loop, (2) emigration of ganglion cells from the epithelium and (3) invagination of semicircular canal epithelium. E10.5 otic vesicle was maintained using the same method, but morphogenesis was less successful. Culture of the E11.5 cochlear region alone resulted in regeneration of a structure with semicircular canal character from the cut end, indicating that region-specific cell fate within the otic vesicle is not irreversibly determined at this stage. Co-culturing otic vesicle with cochleovestibular ganglion (CVG) resulted in enhanced looping or ectopic diverticulum formation of the cochlear region, suggesting that the CVG provides a morphogenetic signal for cochlear looping. Cochlear looping was specifically blocked by inhibiting actin polymerization by cytochalasin D, while morphogenesis of the semicircular canal region remained intact. Hyaluronidase treatment inhibited semicircular canal morphogenesis, resulting in a cystic form of the otic vesicle. These data validate this culture system as a tool for elucidating the mechanism of morphogenesis of the otic vesicle.

A cross-linking reagent is required to improve mechanical strength and degradation properties of biopolymers for tissue engineering. To find the optimal preparative method, we prepared diverse genipin-cross-linked chitosan/collagen scaffolds using different genipin concentrations and various cross-linking temperatures and cross-linking times. The compressive strength increased with the increasing of genipin concentration from 0.1 to 1.0%, but when concentration exceeded 1.0%, the compressive strength decreased. Similarly, the compressive strength increased with the increasing of temperature from 4 to 20°C, but when temperature reached 37°C, the compressive strength decreased. Showing a different trend from the above two factors, the effect of cross-linking time on the compressive strength had a single increasing tendency. The other results also demonstrated that the pore size, degradation rate and swelling ratio changed significantly with different cross-linking conditions. Based on our study, 1.0% genipin concentration, 20°C cross-linking temperature and longer cross-linking time are recommended. Long Bi and Zheng Cao contributed equally to this work.

Objective: The damage to cartilage collagen is a central event in the pathogenesis of cartilage aging and osteoarthritis (OA). We have previously developed an in vitro model of cartilage degradation which shows that chondrocyte-dependent lipid peroxidation mediates cartilage collagen degradation. The goal of our study was to investigate the role of vitamin C in this degradation model and to investigate effect of chondrocyte-dependent lipid peroxidation in the oxidation of cartilage collagen. Methods: We studied primary articular chondrocytes. Effect of vitamin C was investigated in the previously described model. Serum-free stimulated and unstimulated chondrocyte-matrix extracts were subjected to SDS-PAGE and immunoblot analysis. Malondialdehyde (MDA)-protein oxidation of cartilage proteins was demonstrated by the reactivity of chondrocyte extracts to a monoclonal antibody, MDA2, which detects MDA-lysine adducts. Results: Vitamin C treatment of chondrocyte cultures resulted in significant enhanced incorporation of 3H-proline label in cell-matrix. Cells treated with vitamin C, as compared to control untreated cells showed decreased spontaneous release of labeled matrix. Vitamin C treated or not treated chondrocytes responded comparably to stimulation with the agonist calcium ionophore A23187. The serum-free in vitro culture of chondrocytes resulted in MDA-protein oxidation. The treatment of chondrocytes with A23187 resulted in the enhancement of MDA-protein oxidation. The immunoblot reactivity pattern of extracts to MDA2 antibody and to polyclonal anti-type II collagen antibody was somewhat similar, which suggests that these two different types of antisera exibit a crossreaction to chondrocyte proteins. Chondrocyte extracts were pretreated both with and without pure collagenase, and then subjected to immunoblot analysis. Only collagenase treated extracts showed a disappearence, or significant reduction, of larger than 60 kDa size MDA2 immunoreactive proteins. This suggests that the proteins that disappeared after the enzyme treatment were collagen proteins and which had also been modified by MDA oxidation. Conclusions: These observations suggest that collagen hydroxylation of matrix by vitamin C does not play a role in this model of chondrocyte-dependent collagen degradation. Also, this study demonstrates that chondrocyte-derived lipid peroxidation product MDA mediates oxidation of cartilage collagens. Oxidative modification of cartilage collagen in vivo could result in alteration of biochemical and biophysical properties of cartilage collagen fibrils, making them prone to degradation, thus initiating the changes observed in aging and OA.

Tubulointerstitial nephritis (TIN) antigen has been recently identified as a novel basement membrane macromolecule. It consists of a single chain of 58 kDa and exhibits a restricted distribution. The interaction between TIN antigen and laminin or type IV collagen has been studied using solid-phase binding assays and found to be for both macromolecules specific, saturable, and with an affinity in the low micromolar range. In similar assays, TIN antigen did not interact with heparin. In turbidimetry assays, it was found that the presence of TIN antigen did not affect the polymerization of type IV collagen but had a concentration-dependent inhibitory effect on laminin polymerization and on preformed laminin polymers. TIN antigen was able to promote adhesion of epithelial cells derived from kidney tubules and of endothelial cells derived from aorta. The data suggest that TIN antigen may be a macromolecule of importance both for basement membrane ultrastructure and cellular adhesion.

Aim Numerous materials have been used to replace defects in the dura mater as result of neurosurgical and spinal procedures. Tissudura is a biomatrix made of cross-linked equine collagen fibrils, mainly of the interstitial type I. The specially engineered dura-like layered structure provides a non porous primary water tight structure, is transparent and allows verification of the efficacy of cerebral hemostasis. Methods A consecutive series of patients between 18 years and 75 years of age were prospectively enrolled from three separate European institutions between May 2007 and February 2008. All patients underwent elective cranial or spinal surgery and required implantation of a dural substitute. We assessed the efficacy and safety of the collagen biomatrix as a dural substitute, intraoperatively and postoperatively, with a median follow-up 4.3 months. Results Fifty-six patients had cranial surgery, four patients underwent a spinal operation. Surgical cranial approaches included supratentorial procedures in 45 patients and posterior cranial fossa exploration in 11.

Background. This research was aimed to study the biochemical changes in cervical mucus after application of laminaria tent. Marerial and methods. Cervical mucus was collected before and after insertion of laminaria tent from 20 normal pregnant women in the first and second trimesters. Interleukin-1 p, IL-8, collagenase activity, elastase activity, PGE? and PGF2a were measured in the collected samples. Laminaria tent was also inserted in one vaginal cervix of five non-pregnant rabbits and the clinical and histological changes were compared with five non-treated rabbits. Collagen contents were assessed histologically and Leukocyte number was counted. Results. IL-Ip and IL-8 and elastase activity were significantly increased after insertion of laminaria @<O.OOOl, 0.001 and 0.001 respectively). Collagenase activity was not significantly changed. Whereas concentration of PGE, and PGF,a in the mucus were markedly increased @<0.0001 and 0.001 respectively). Collagen contents were significantly decreased in laminaria and opposite side cervices @<0.0001). No significant changes in leukocyte count could be observed in treated and non treated cervices.

Chronic leg wounds are characterized by defective remodeling of the extracellular matrix, failure of reepithelialization, and prolonged inflammation. The hypothesis that this defective extracellular matrix remodeling is associated with phenotypic differences in the activity of the matrix ...

IntroductionObtaining hemostasis in the surgical crypt during periradicular surgery is essential. It allows for improved visibility and contributes to a dry environment suitable for the placement of moisture-sensitive root-end filling material. Although current materials may not be moisture sensitive during setting, hemostasis is important for proper placement of root-end filling materials during apical surgery. A new hemostatic agent, HemCon dental

The present study was designed to analyze the regulation of the levels of the polyamines and their biosynthetic enzymes during embryonic development of Xenopus laet:is. The activity of omithine decarboxylase (ODC), a rate-controlling enzyme in polyamine biosynthesis, is elevated until, during gastrulation, there is a precipitous drop in activity. This is not attributable to a decrease in ODC mRNA content and polysome profiles reveal no apparent decrease in ODC message associated with polysomes. ODC synthesis seems to be maintained at a low, relatively constant rate until neurulation whereupon ribosome loading of ODC mRNA increases. During gastrulation the rate of ODC degradation increases dramatically, which can account for the decrease in ODC. S-Adenosylmethionine decarboxylase (AdoMetDC), another rate-controlling enzyme in polyamine biosynthesis, shows a low and constant activity from cleavage to neurulation. Subsequently, the AdoMetDC activity increases dramatically. The changes in AdoMetDC activity parallel the changes in AdoMetDC mRNA levels, suggesting a transcriptional control of AdoMetDC expression during this developmental period. The activities of ODC and AdoMetDC produce a steady increase in putrescine and spermidine content of the embryo. The spermine content also increases until gastrulation, but then decreases until the tailbud stage. . Fax: + 46 90 16669 I. 0167-4781/95/$09.50 © 1995 Elsevier Science B.V. All rights reserved SSDI 01 67-4781 (95)001 36-0

Genomic and cDNA clones of a mcol gene encoding mini-collagen (MCOL), a nematocyst capsule protein, have been isolated from a reef-building coral, Acropora donei (Anthozoa). The gene and its flanking regions, comprising 5382 bp and covering three exons and two introns, were sequenced. Exons 2 and 3 together have an open reading frame which can encode a MCOL of 176 amino acids (aa). The coral MCOL has all the characteristic regions present in the four hydra MCOL specified by the four mcol cDNA clones previously isolated from Hydra magnipapillata (Hydrozoa) by Kurz et al. I-J. Cell Biol. 115 (1991) 1159-1169, including a central Gly-Xaa-Yaa region and flanking Pro-rich and Cys-repeat regions. This observation suggests that a mcol family is highly conserved in Anthozoa and Hydrozoa, and also that the characteristic regions present in MCOL are essential for the structure and function of these peptides.

Background: The effect of vasopressors on the healing of gastrointestinal anastomoses is still controversial. The purpose of our study was to research the relationship between dose of dopamine, which is used generally as a vasopressor in shock status, and anastomotic leak in colonic surgery. Methods: Forty-two male New Zealand rabbits were included in the study. Under general anesthesia, the right colon was identified, incised, and divided 5 cm distal to the ileocecal valve. Colonic integrity was then established with end-to-end anastomosis in all animals. The animals were randomized into 6 groups. While group 1 was not given any vasopressors, groups 2, 3, 4, 5, and 6 were administered 5, 10, 15, 20, and 25 mg kg À1 h À1 dopamine infusions, respectively, for 2 h. On the 4th postoperative day, relaparotomy was performed under general anesthesia. The bursting pressures of anastomoses (BPA) were measured in situ, and then the lines of anastomoses were excised. The levels of hydroxyproline and collagen were measured in this tissue. Results: When compared with the control group (140 AE 39 mmHg), BPA were found to be statistically increased only in group 5 (238 AE 91 mmHg) (p ¼ 0.03) and group 6 (277 AE 64 mmHg) (p ¼ 0.002). There were no differences between groups in terms of the hydroxyproline and collagen levels in the tissue (p > 0.05). Conclusions: Although vasopressors appeared to increase the risk of anastomotic leakage as a result of splanchnic vasoconstriction, deterioration of microcirculation, and local hypoxia, we found that BPA were increased with high doses of vasopressor. We speculated that the use of vasopressors without shock might increase blood supply to the anastomotic line by increasing cardiac output.

La peau et la cornée sont deux tissus de revêtement constitués d'un épithélium fermement ancré à un tissu conjonctif, le derme pour la peau et le stroma pour la cornée. Les cellules souches de la peau ont pu être amplifiées grâce à la technique de Rheinwald et Green en 1975 et utilisées dès 1981 sous forme de feuillets épidermiques pour le traitement des grands brûlés. Plus tard, cette technique de culture a été reprise pour amplifier les cellules épithéliales limbiques. La couche basale de l'épithélium limbique se situe dans la zone transitionnelle entre la cornée et la conjonctive et contient les cellules souches de l'épithélium cornéen [J Cell Biol 1 (1986) 49-52 et Cell 57 (1989) 201-209] appelées cellules souches limbiques (CSL). Elles assurent le renouvellement de l'épithélium cornéen en générant des cellules d'amplifications transitoires qui migrent de façon centripète à partir de la couche basale limbique vers la couche basale de la cornée. Le génie tissulaire permet de reconstruire des tissus en trois dimensions (3D), associant l'épithélium à son tissu conjonctif sous-jacent. Pour reconstruire le tissu conjonctif, notre modèle associe des cellules et un polymère biodégradable et naturel à base de collagène. Ce substrat poreux sert d'échafaudage à la culture de fibroblastes pour donner un derme/ stroma équivalent vivant, qui secondairement épithélialisé aboutit à une peau/hémicornée reconstruite. Nous présentons ici : la reconstruction des épithélia dans les pathologies de surface de la peau et de la cornée et le développement de nos modèles tridimensionnels de peau et de cornées à base de collagène-GAG-chitosane et leurs applications.

A significant amount of new bone was formed by 6 months postoperatively in each group. The mean change in bone height in the rhBMP-2/ACS subjects was 7.83 ± 3.52 mm versus 9.46 ± 4.11 mm for the bone graft subjects. At 6 months after dental restoration, the induced ...

Chronic pancreatitis is a severe inflammation of the pancreas associated with destruction of the parenchyma, fibrosis, and persistent abdominal pain. Cyclooxygenase-2 (COX-2) and COX-2-derived prostaglandins, key mediators of the inflammatory response, are elevated in patients with chronic pancreatitis. Previous studies investigated COX-2 as a therapeutic target. These reports showed a reduced pathology in COX-2-deficient mice with a better outcome. Here we compared the role of COX-2 in acute and chronic pancreatic inflammation using the same COX-2−/− mouse model of cerulein-induced pancreatitis. In a setting of acute pancreatitis, juvenile COX-2−/− mice exhibited a reduced histopathological score compared with wild-type littermates; on the contrary, adult mice did not show any difference in the development of the disease. Similarly, in a setting of chronic pancreatitis induced over a period of 4 wk, adult mice of the two strains showed comparable histological score and collagen dep...

Osteotome techniques are used as a less invasive alternative to the lateral window osteotomy to increase the volume of bone in the posterior maxilla. Implants may be placed simultaneously for four to six months after performing osteotome-mediated sinus floor elevation, depending upon the residual crestal bone remaining beneath the sinus floor. This article describes the clinical indications and techniques for localized internal sinus elevation using osteotomes. The incorporation of this minimally invasive crestal approach to sinus augmentation into the clinical practice results in increased case acceptance with reduced treatment duration, trauma and cost.

Cartilage injury remains a major challenge in orthopedic surgery due to the fact that articular cartilage has only a limited capacity for intrinsic healing. Cartilage impaction is followed by a post-traumatic inflammatory response. Chondrocytes and synoviocytes are activated to produce inflammatory mediators and degradative enzymes which can induce a progradient cartilage self-destruction finally leading to secondary osteoarthritis (OA). However, an anti-inflammatory compensatory response is also detectable in cartilage by up-regulation of anti-inflammatory cytokines, probably a temporary attempt by chondrocytes to restore cartilage homeostasis. Matrix-assisted autologous chondrocyte transplantation (MACT) is a suitable technique for improving the rate of repair of larger articular cartilage defects. For MACT, autologous chondrocytes were isolated from a cartilage biopsy of a non-load bearing joint area. This technique requires sufficient expansion of differentiated autologous chondrocytes, which were then seeded on suitable biodegradable threedimensional (3D) matrices to preform an extracellular cartilage matrix (ECM) before implantation into the defect. Cell expansion is accompanied by chondrocyte dedifferentiation, whereby substantial changes occur at multiple levels of chondrocyte synthetic profiles: including the ECM, cell surface receptors and cytoskeletal proteins. Since these dedifferentiated chondrocytes produce a non-specific mechanically inferior ECM, they are not suitable for MACT. 3D cultures are means of inducing and maintaining chondrocyte (re)differentiation and to preform ECM. The combination of MACT with anabolic growth factors and anti-inflammatory strategies using anti-inflammatory mediators might be useful for stabilizing the differentiated chondrocyte phenotype, to support neocartilage formation and

Upon stimulation with agonists, platelets express CD40 ligand (CD40L), a transmembrane protein implicated in the initiation and progression of atherosclerotic disease. We have recently discovered that oxidative stress plays a major role in platelet CD40L expression. In this study, we sought to determine whether vitamin C, a known antioxidant, is able to influence platelet CD40L expression. In vitro experiments were done by stimulating platelets with collagen in the presence or absence of vitamin C (50-100 AM) or vehicle as control. An in vivo study was done in 10 healthy subjects who were randomized to intravenous infusion of placebo or 1 g vitamin C for 45 min in a crossover design. At the end of infusion platelet CD40L and O 2-were measured. The in vitro study demonstrated that vitamin C dose dependently inhibited platelet CD40L expression without affecting agonist-induced platelet aggregation. In subjects treated with placebo no changes of platelet CD40L and O 2-were observed; conversely, vitamin C infusion caused a significant and parallel decrease of platelet O 2-(À70%, P b 0.001) and CD40L (À68%, P b 0.001). Platelet aggregation was not modified by either treatment. This study suggests that water-soluble antioxidants, which scavenge superoxide radicals, may reduce platelet CD40L expression.

cal evaluation. Stressed animals had higher adrenal weights compared to non-stressed groups, which were reduced by 1400W treatment. Behavioural stress in sensitised animals amplified the resistance and elastance responses after antigen challenge, numbers of eosinophils and iNOS+ cells, actin content and 8-iso-PGF2 ␣ density in the distal lung compared to the OVA group. 1400W treatment in ovalbumin-exposed and stressed animals reduced lung mechanics, iNOS+ cell numbers and 8-iso-PGF2 ␣ density compared to sensitised and stressed animals that received vehicle treatment. We concluded that stress amplifies the distal lung constriction, eosinophilic inflammation, iNOS expression, actin content and oxidative stress previously induced by chronic lung inflammation. iNOS-derived NO contributes to stress-augmented lung tissue functional alterations in this animal model and is at least partially due to activation of the oxidative stress pathway.

Collagens of most connective tissues are subject to continuous remodelling and turnover, a phenomenon which occurs under both physiological and pathological conditions. Degradation of these proteins involves participation of a variety of proteolytic enzymes including members of the following proteinase classes: matrix metalloproteinases (e.g. collagenase, gelatinase and stromelysin), cysteine proteinases (e.g. cathepsin B and L) and serine proteinases (e.g. plasmin and plasminogen activator). Convincing evidence is available indicating a pivotal role for matrix metalloproteinases, in particular collagenase, in the degradation of collagen under conditions of rapid remodelling, e.g. inflammation and involution of the uterus. Under steady state conditions, such as during turnover of soft connective tissues, involvement of collagenase has yet to be demonstrated. Under these circumstances collagen degradation is likely to take place particularly within the lysosomal apparatus after phagocytosis of the fibrils. We propose that this process involves the following steps: (i) recognition of the fibril by membranebound receptors (integrins?), (ii) segregation of the fibril, (iii) partial digestion of the fibril and/or its surrounding noncollagenous proteins by matrix metalloproteinases (possibly gelatinase), and finally (iv) lysosomal digestion by cysteine proteinases, such as cathepsin B and/or L. Modulation of this pathway is carried out under the influence of growth factors and cytokines, including transforming growth factor [~ and interleukin lct.

To evaluate in vivo collagen fiber behavior around two different dental implant necks placed in the mandibular bone of adult pigs. Scanning electron microscopic (SEM) and profilometric analyses were performed on both types of implant necks to evaluate the different surface morphology. Ten dental implants with machined titanium necks and 20 implants with zirconia necks were inserted into the mandibles of five adult pigs. Three months later, the animals were sacrificed; samples from the peri-implant mucosa were obtained and prepared for histologic analysis. Evaluation of collagen fiber orientation in the connective tissue surrounding the implant necks was performed by polarized light microscopy. Inflammation in the peri-implant soft tissues was also measured via the Gingival Index. Postoperative healing was uneventful; all implants, except for one of each type, were osseointegrated after 3 months. SEM and profilometric analyses confirmed that zirconia necks showed Ra, Rq, and Rz value...