Dense Regular Connective Tissue Research Articles

Carbon Nanotube/MXene Composite with a Dense Regular Connective Tissue Structure and Its Application in Lithium-Ion Batteries

Carbon Nanotube/MXene Composite with a Dense Regular Connective Tissue Structure and Its Application in Lithium-Ion Batteries

Morphological description of the temporomandibular joint ligaments in domestic pigs.

The temporomandibular joint (TMJ) ligaments play crucial roles in its function or dysfunction. The objective of this study was to describe the macro and microscopic morphology of these ligaments in domestic pigs, aiming to: (1) expand knowledge about the species; (2) provide anatomical references for advancing veterinary therapy and utilizing pigs as animal models in craniofacial research. Heads of young Sus scrofa domesticus were dissected to identify TMJ ligaments. Fragments of these ligaments were collected and processed for subsequent histological analysis with Haematoxylin and eosin staining. The results were qualitatively described. Pigs exhibited a TMJ reinforced by three individualized capsular ligaments: a lateral ligament, attaching to the ventral margin of the zygomatic process of the temporal bone and the lateral margin of the mandibular neck; a caudomedial ligament, attaching to the retroarticular process of the squamous part of the temporal bone and the caudomedial margin of the mandibular neck and a caudolateral ligament, attaching to the ventral margin of the base of the zygomatic process of the temporal bone and the caudal margin of the mandibular neck. The lateral ligament exhibited a greater constitution of dense irregular connective tissue, while the caudomedial and caudolateral ligaments showed a greater constitution of dense regular connective tissue. It is concluded that the TMJ of pigs presents one more ligament than horses, cattle, dogs, cats and what has been described for pigs themselves. We believe these results may contribute to the improvement of veterinary clinical and surgical therapy overall, as well as provide essential morphological information for a better interpretation and application of interspecies results in craniofacial research using pigs as an experimental model, as in the case of humans.

Decellularization of Dense Regular Connective Tissue-Cellular and Molecular Modification with Applications in Regenerative Medicine.

Healing of dense regular connective tissue, due to a high fiber-to-cell ratio and low metabolic activity and regeneration potential, frequently requires surgical implantation or reconstruction with high risk of reinjury. An alternative to synthetic implants is using bioscaffolds obtained through decellularization, a process where the aim is to extract cells from the tissue while preserving the tissue-specific native molecular structure of the ECM. Proteins, lipids, nucleic acids and other various extracellular molecules are largely involved in differentiation, proliferation, vascularization and collagen fibers deposit, making them the crucial processes in tissue regeneration. Because of the multiple possible forms of cell extraction, there is no standardized protocol in dense regular connective tissue (DRCT). Many modifications of the structure, shape and composition of the bioscaffold have also been described to improve the therapeutic result following the implantation of decellularized connective tissue. The available data provide a valuable source of crucial information. However, the wide spectrum of decellularization makes it important to understand the key aspects of bioscaffolds relative to their potential use in tissue regeneration.

Histo-morphological features of the efferent ductules of the African straw-coloured fruit bat (Eidolon helium)

Introduction: The African straw-coloured fruit bat plays important roles as pollinators, seed dispersers and important carrier of zoonotic diseases. It is a non-hibernating seasonal breeder whose reproductive biology had received little attention. The aim was to study the histomorphology of the efferent ductules of Eidolon helvum using 10 adult male bats. Methods: The efferent ductules were obtained from the adult bats, fixed by immersion in neutral-buffered formalin and prepared for histology and histochemistry. Results: The result showed that the entire epididymis was enclosed by the thick dense regular connective tissue, tunica albuginea. Within the connective tissue, tubules of efferent ductules occurred in lobules. These lobules were separated from each other by connective tissue trabeculae. The efferent ductules are tiny tubules that connect the rete testis to the initial segments of the epididymis. Each efferent ductule was lined by a simple columnar epithelium of two cell types, containing the ciliated and the non-ciliated cells. The non-ciliated cells were more numerous exhibiting oval shapes, basally located euchromatic nuclei with prominent nucleoli. The ciliated cells were fewer and appeared as dark cells with oval to elongated, centrally or apically located heterochromatic nuclei. Cilia projected from the apical surfaces of the ciliated cells into the lumen. PAS/Alcian blue staining showed presence of PAS positive secretions in the apical cytoplasm of the non-ciliated cells. Significance: These findings indicate that the morphology of efferent ductules of the African straw-coloured fruit bat have similar morphology with most mammals but differ from those of insectivorous bats.

Comparative Analysis of Connective Tissue Responses to Implantation of Biodegradable Material and Polypropylene in Experimental Animals.

We compared qualitative characteristics of the connective tissue at the site of implantation of polypropylene or a biodegradable polymer synthesized by electrospinning and consisting of 65% polycaprolactone and 35% polytrimethylene carbonate. Synthetic materials were implanted into the interfascial space of the muscles on the back of Wistar rats. The parameters of cellular and non-cellular structures of the forming connective tissue were studied in 1, 2, 3, 6, 9, and 12 months after implantation. It was found that the number of fibrocytes and fibroblasts around biopolymer and polypropylene increased during the period from 1 to 9 months, with a significant lag in case of biopolymer implantation; by 12 months, the number of fibrocytic cells did not significantly differ. The fibroplastic and angioplastic processes developed in the thickness of both materials, but with a one-month lag in case of biopolymer implantation due to degradation properties and nonporous structure of this polymer. Collagen fibers were actively synthesized around both materials, but in case of polypropylene, this process was more pronounced. In 6 months after implantation of polypropylene, dense regular connective tissue was formed; in 12 months after implantation of the biopolymer, the formation of dense irregular connective tissue was observed at the site of implantation. The biopolymer can be used to strengthen the core muscles.

Fibrocartilaginous metaplasia and neovascularization of the anterior cruciate ligament in patients with osteoarthritis.

The anterior cruciate ligament (ACL) prevents the anterior translocation and medial rotation of the tibia against the femur. It is typically composed of dense regular connective tissue (DRCT), small amount of loose connective tissue, little vasculature, and few nerve endings. The objective of the current study was to evaluate the details of histological changes in ACLs of patients with clinically diagnosed osteoarthritis (OA). The ACLs of six patients undergoing total knee replacement because of OA (OA group) were compared with 16 normal ACLs from cadavers (control). The ACLs were analyzed for tissue composition and number of blood vessels across the full length and thickness of the ligament. Percentages for areas of DRCT, fibrocartilage, degenerative tissue, and vasculature were calculated. Tissue composition and relative number of blood vessels were compared between groups. The proportion of DRCT to non-DRCT was significantly smaller in the OA group than the control group (p < .001); non-DRCT included degenerative connective tissue and fibrocartilage. The number of blood vessels to area was greater in the OA group than the control group (p = .002). Six of control (37.5%) and five of OA ACLs (83%) showed areas of calcification. These results indicate that inflammatory processes contributing to OA in the knee cause changes in the composition of the ACL that lead to destruction of collagen bundles, increased vascularization, calcification, and formation of fibrocartilage-like tissue inside the ligament. These changes make ligament-retaining total knee arthroplasty a less beneficial option for knee repair.

Histological Study of the Anterior Cruciate Ligament in Patients with Osteoarthritis

The anterior cruciate ligament (ACL) plays a crucial role in preventing the anterior translocation and medial rotation of the tibia against the femur. The normal histological composition of the ACL has been described as 99% dense regular connective tissue (DRCT), 0.9% loose connective tissue, and 0.1% vasculature with no nerves or adipose tissue present. Previous data on ACL structure in patients with knee osteoarthritis (OA) indicate that the ligament undergoes degenerative changes in OA patients. The objective of the current study was to evaluate the details of histological changes in the ACLs of patients with clinically diagnosed OA. The study was approved by the local institutional review board. The ACLs from six patients undergoing total knee replacement because of OA (OA group) and eleven normal ACLs from the Kirksville College of Osteopathic Medicine anatomy lab (control group) were collected. Demographic data, medical history, and Outerbridge scores were also collected. The average Outerbridge score in the OA group was 3.6 on a scale of 0–4. Nonconsecutive 10 μm longitudinal tissue slices of ACLs stained with hematoxylin and eosin were analyzed for tissue composition and amount of blood vessels. To account for possible differences in tissue composition across the ligament, the full length and full thickness of each ACL were analyzed using nine sections from each ACL, from which the data were averaged. ImageJ software was used to calculate percentages for total area and areas of DRCT, degenerative tissue, and vasculature. Generalized linear mixed models were used to compare tissue composition and relative amount of blood vessels in the OA and control groups. There was no significant difference in tissue composition or vasculature between age groups (both P&gt;.37). The major difference in the histological structure of the ACL between the two groups was the proportion of DRCT to non‐DRCT, which was significantly smaller in the OA group than the control group (OA, 50%; control, 96%; P&lt;.001). The non‐DRCT included degenerative connective tissue and fibrocartilage. The ratio of blood vessels to area was greater in the OA group than the control group (OA, 0.12 vessels/mm2; control, 0.02 vessels/mm2; P=.01). These results indicate that the inflammatory processes in the knee contributing to OA lesions cause changes in the composition of the ACL that lead to destruction of collagen bundles, increased vascularization, edema, and formation of fibrocartilage‐like tissue inside the ligament. Thus, the ACLs from patients with severe OA undergo marked histological changes, making them less suitable for ligament‐retaining total knee arthroplasty.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The biomechanical and morphological characteristics of the ligamentum mucosum and its potential role in anterior knee pain

BackgroundThe ligamentum mucosum is composed of dense regular connective tissue and traverses from the distal femur to the infrapatellar fat pad. While the gross and histologic morphology has been studied, there is currently no evidence concerning the biomechanical properties of the ligamentum mucosum and the potential of anterior knee pain.The purpose of this study was to determine the anatomical, mechanical and histological properties of the ligamentum mucosum. MethodsDissections were performed on cadaveric knee specimens (N = 18) and histological analysis (n = 6) was performed to define the anatomical characteristics of the ligamentum mucosum using standard hematoxylin and eosin (H&E), Masson's trichrome, and immunohistochemical methods. Biomechanical testing (n = 5) was conducted to determine the tensile properties of the ligamentum mucosum. The peak load at failure, stiffness, and strain were analyzed. ResultsSixty-four percent of the knees had a ligamentum mucosum and the histological analysis confirmed it to be composed of dense regular connective tissue. Small peripheral nerves were identified in the junction between the ligamentum mucosum and the fat pad. The average (SD) peak force of failure, stiffness, and strain were 31.9 N (19.0), 5.1 N/mm (3.59), and 0.83 (0.14), respectively. ConclusionsThe tensile strength and stiffness of the ligamentum mucosum is considerably less than the primary stabilizers of the knee joint. Based on these findings, it is improbable that the ligamentum mucosum has a meaningful effect on the kinematics of the extensor mechanism; perturbations of the tissue and the connected infrapatellar fat pad could potentially play a role in the pathogenesis of anterior knee pain.

Morphological peculiarities of three-dimensional structure of tendinous cords of antrioventricular heart valves in human newborns

Objective — the aim of the study was to examine features of the structure of tendinous cords of atrioventricular valves in newborns by using optic lighting and reconstruction methods of investigation.Material and methods. Tendinous cords of the mitral and tricuspid valves were examined on 52 specimens atrioventricular heart valves, taken from 26 newborns who had died due to the causes which were not associated with pathology of the cardio-vascular system. During the study we used optical method, three-dimensional reconstruction and statistical analysis.Results. Results of microscopic studies have shown that tendinous cords consist of dense regular connective tissue, where between bundles of collagen fibers cells of fibroblastic range can be found. However, in thickness of 28% tendinous cords, except bundles of collagen fibers, bundles of cardiac muscle have been also found. With the help of three dimensional tendinous cords reconstructions, it was established that the subendothelial layer is a loose collagenous-elastic periphery with blood vessels inside. The central part is formed by collagen core.Conclusion. Therefore, the results of morphological studies have shown that 72% tendinous cords of atrioventricular heart valves in newborns belong to the fibrous, and 28% belong to fibro-muscular type of tendinous cords.

Absence of bony patella in the white-eared opossum (Didelphis albiventris): Morphology and diagnostic imaging.

Patella, the kneecap, is the best known and largest of the sesamoid bones and is present in the quadriceps femoris tendon. Typical patella appears in all extant mammals, with the exception of some marsupials and bats. No description about the white-eared opossum stifle was found in the available literature up to now. Thus, the knee joints of 16 Didelphis albiventris were examined by gross anatomy, histology, radiography and computed tomography images to determine the presence or absence of ossified patella in this animal. The most remarkable observation in white-eared opossum is the absence of a bony patella. The femoral trochlea is shallow, and the lateral gastrocnemius sesamoids are shown up in all opossums. The quadriceps femoris tendon is composed mainly of dense regular connective tissue with a classic fibrocartilage pad on the superficial surface of the tendon. The absence of a true patella seems to be typical for marsupials.

Morphological Studies on Penis of Rabbit

Rabbits characterized by their suitability as a laboratory animal and to their renowned reproductive efficiency. The present work was to understand the normal penile morphology to improve the basic scientific knowledge of the organization of the penile structures. The current study revealed that, the penile fibrous skeleton consisted of the thick lamellated tunica albuginea and the penile trabecular system was nearly parallel and vertical. It was observed to be composed of collagen fibers. The tunica albuginea that surrounds the corpora cavernosa penis was made up of dense regular connective tissue consisted of inner concentric lamellae and an outer longitudinal layer permeated with smooth muscle cells. At the tip of the penis the number of trabecular is greatly diminished. No distinct tunica albuginea surrounded the corpus spongiosum penis, the penile erectile tissues were made up of cavernae lined by endothelium and surrounded by smooth muscles and dense irregular mainly collagenic fibers. The smooth muscle was the most abundant component of the penile erectile tissue. The penile urethra in the rabbit was lined varies in different regions, in the greatest part of the penile urethra it is lined by stratified cuboidal to columnar epithelium. In conclusion: the penis of the rabbit was of musculo-cavernous type. The os-penis and the glans penis were absent. However, the glans penis was replaced by the pars libra

The Morphological &amp; Biomechanical Characteristics of the Ligamentum Mucosum and its Potential Role in Anterior Knee Pain

IntroductionThe ligamentum mucosum (LM), or infrapatellar plica, is a non‐isometric structure of the knee joint that traverses from the intercondylar notch of the femur to the infrapatellar fat pad. The LM is composed of dense regular connective tissue, of which four different morphologies have been identified: separate, vertical septum, split, and fenestrated. Microscopically, pathological LM appears fibrotic and calcified, which can lead to impingement, and ultimately may be implicated in the pathogenesis of anterior knee pain. The specific aims of this study are to investigate the anatomical relationship of the LM to neighboring structures, determine whether the histological characteristics of the LM further define its function and its potential role in proprioception, and lastly to perform an in vitro biomechanical analysis of the LM under normal physiological loading.MethodologyFresh‐frozen cadaveric knee specimens (n=14) were dissected to reveal the structures of the joint capsule and to identify the morphology of the ligamentum mucosum. With the knee at 90° flexion, four measurements were recorded in order to examine the important relationships within the joint capsule. The intraclass correlation coefficient was calculated to determine the consistency and reproducibility of the measurements recorded. Maintaining the proximal and distal attachments, two specimens were harvested for histological analysis using standard hematoxylin and eosin, Masson's trichrome for collagen, and mono‐clonal mouse anti‐human neurofilament protein to identify neurons and peripheral nerve endings.ResultsOverall, 64% of the knees had a LM present. With respect to morphology, 50% of the 14 specimens had a separate type, 14% had a vertical septum type, and the remaining specimens had no LM present, which is consistent with known classification systems. The histological analysis confirmed the LM to be ligamentous, thus being composed of dense regular connective tissue. Preliminary immunohistochemistry results are inconclusive at this time for evidence of peripheral nerves and nerve endings, and the biomechanical properties of LM have yet to be determined.DiscussionThe role of LM in anterior knee pain is not well documented; however, studies have shown that excising the LM can relieve idiopathic anterior knee pain. With a decrease in elasticity, pathological LM may result in patellar maltracking and instability, ultimately triggering anterior knee pain. Future biomechanical testing will utilize an Instron materials testing machine to load the ligaments under tension at a constant velocity in order to determine the force at which the specimen fails. Thus, the findings from this study can be implemented in models of anterior knee pain, more specifically models of patellar instability and maltracking, to determine the proprioceptive and pathogenic mechanisms of the ligamentum mucosum.

On the connection between the tympanic membrane and the malleus

BackgroundThe tympano-mallear connection (TMC) is the soft-tissue connection between the tympanic membrane (TM) and the manubrium of the malleus. Some studies suggest that its mechanical properties may have a substantial influence on the mechanics and transfer function of the middle ear. However, relatively little is known about the dimensions of the TMC and its variability among individuals. MethodThirteen samples were collected from human temporal bones, consisting of only the malleus and the TM. They were imaged using μCT without contrast enhancing agent. From the μCT images, the TMC dimensions were measured in both anterior–posterior direction (TMC width) and medial-lateral direction (TMC thickness). Three selected samples were examined using histological microscopy. ResultsBoth TMC width and thickness featured a large variability among individuals. The minimal TMC width along the manubrium for different individuals covered a range between 83 and 840 μm. The minimal thickness ranged from 48 to 249 μm and the maximal thickness from 236 to 691 μm. Histological sections showed that the TMC consists of a narrow core of dense regular connective tissue, surrounded by loose connective tissue. In some samples, either of these two components was absent in the TMC at some manubrium locations. The configuration of these components varied among the samples as well. ConclusionOur data confirm that a large inter-individual variability exists in the properties of the TM-malleus connection in humans in terms of its dimensions, tissue composition and configuration. Average data and their variability margins will be useful input for testing the importance of the TMC in finite element models.

Anatomical, light and scanning electron microscopical study of ostrich (Struthio camelus) integument

The current study dealt with the gross and microscopic anatomy of the integument of male ostrich in addition to the histological features of different areas of skin. The ostrich skin is characterized by prominent feather follicles and bristles. The number of feather follicles was determined per cm2 in different regions. The integument of ostrich had many modifica- tions, which appeared as callosities and scales, nail and toe pads. They were sternal, pubic and Achilles tendon callosities. The vacuolated epidermal cells were seen mainly in the skin of legs and to a lesser extent in the skin of back and Achilles areas. Higher lipogenic potential was ex- pressed by epidermis from glabrous areas of ostrich skin. The dermal papillae were found in the skin of feathered area of neck and back and this was not a common finding in bird's skin, which may give resistance against shearing forces in these regions of ostrich skin. The thickness of the keratin layer of ostrich varied, being thick and characteristically loose in the skin at legs, very thin and wavy at neck, while at Achilles skin area, scales and toe pad were thick and more compact, with the thickest very dense and wavy keratin layer at the nail. The dermis consisted of superficial layer of dense irregular connective tissue characterized by presence of many vacuoles of different sizes just under the basal lamina of the epithelium of epidermis and deep layer of dense regular connective tissue. This result suggested the presence of fat droplets in this layer which may be to overcome the lack of good barrier of cutaneous water loss in epidermis.

Lip Histology of the Adult Farmed African Catfish (&lt;i&gt;Clarias gariepinus&lt;/i&gt;)

The lip histology of the adult farmed African catfish was investigated to fill the knowledge gap in available literature especially those from commercial concrete tanks. This microanatomy is important as the lip is the principal organ involved in prehension. The lip epidermis was lined by stratified squamous epithelium containing PAS and AB positive mucous cells, and occasional eosinophilic club cells. Some melanocytes were seen at the basal epithelial layer and subepithelium. Pectinate ligament of dense regular connective tissue was seen attaching the epithelium to the deep dermal dense regular connective tissue. This deep dense regular connective tissue was seen ventral to the subepithelial loose areolar connective tissue. In the lower lip, the core contained skeletal muscle fibres in varying directions, elastic cartilage, and bone. This core provides anchorage for the horny pad teeth. Abundant nerve fibres were observed in the deep connective tissue layers. No taste bud was observed. This microanatomical observation suggests an organ involved in prehension and tearing of feed; protractibility and protection but no gustatory function. Keywords : Clarias gariepinus , Pectinate ligament, mucous cells, club cells, Histology, lip function

Ligamentous Hyperlaxity and Dorsal Wrist Ganglions

To determine whether symptomatic dorsal wrist ganglions are associated with generalized ligamentous hyperlaxity. Ninety-six patients (61 females) presenting to hand surgeons for a symptomatic dorsal wrist ganglions were prospectively enrolled in this case-control investigation. Beighton scores were calculated to quantify generalized ligamentous laxity in each patient, and a scaphoid shift test (scapholunate capsuloligamentous laxity evaluation) was performed. Apositive scaphoid shift test was defined by both pain and a palpable clunk. Ninety-six individuals without ganglions were then enrolled to form an age and sex frequency-matched control cohort. The control group was similarly assessed for Beighton score and scaphoid shift test. Binary logistical regression was performed to assess the association of ganglions with generalized ligamentous hyperlaxity (Beighton score ≥ 4) while accounting for effects of age and sex. Patients with symptomatic dorsal wrist ganglions demonstrated significantly increased rates of generalized ligamentous hyperlaxity. Among those with ganglions, 27 of 96 (28%) patients exhibited generalized ligamentous hyperlaxity, compared with 12 of the 96 (13%) age- and sex-matched individuals in the control group. Patients with symptomatic dorsal wrist ganglions were also significantly more likely to demonstrate localized scapholunate hyperlaxity with a positive scaphoid shift test (25% positive scaphoid shift test with ganglions vs 1% in controls). In logistical modeling, patients with dorsal wrist ganglions had 2.9 (95% confidence interval [CI] 1.3-6.2) times greater odds of generalized ligamentous hyperlaxity compared with patients without a dorsal wrist ganglion after accounting for patient age and sex. Symptomatic dorsal wrist ganglions were associated with both generalized ligamentous hyperlaxity and a positive scaphoid shift test. Although an association between wrist ganglions and ligamentous hyperlaxity does not prove causation, the possibility of the same underlying pathological entity causing both can be envisioned (ie, abnormal formation or organization of dense regular connective tissue). Prognostic III.

The transverse occipital ligament: an anatomic, histologic, and radiographic study

The craniocervical region is an osteoligamentous complex that provides structural stability and movement by means of numerous ligaments. Fundamental knowledge of these ligaments is important for physicians who treat patients with disorders of this region to reduce morbidity and mortality. There is a paucity of data in the literature regarding the morphology, function, and classification of the transverse occipital ligament (TOL). The purpose of this study was to investigate the prevalence, morphology, and variations of the TOL in a large number of adult human cadavers using dissection, histology, and digital radiography. Cadaveric laboratory study. Thirty-two formalin-fixed human adult cadavers were dissected in the study. Fourteen cadavers were found to have a TOL. Measurements using a digital caliper, high-resolution digital photography, histologic staining with bright-field microscopy, and digital radiography. The posterior musculature and related soft tissues were dissected and underlying bony elements removed. The TOL was identified, isolated, measured, and then removed for histologic preparation with hematoxylin and eosin staining. Anteroposterior open-mouth digital radiographs of the upper cervical spine with monofilament attached to the TOL were used to demonstrate its relations to the occiput, atlas, and axis. The TOL was present in 14 of 32 (44%) of the dissected cadavers (six male and eight female). Three types of TOLs were identified. Type 1 had bilateral connections to the alar ligaments and had fibers inserting onto the dens. Type 2 also had bilateral connections to the alar ligaments but did not have fibers inserting onto the dens. Type 3 neither had any connections to the alar ligaments nor had fibers that connected to the dens. Male cadavers always had a Type 1 TOL compared with 3 of 8 (38%) female cadavers and this difference was significant (p=.031). The TOL consisted of dense regular connective tissue with parallel arrangements of collagen fibers and interposed fibroblasts. Our data suggest that the TOL is not an anatomic variant and can be classified into three types. Future biomechanical studies can be designed to investigate the function of the TOL, although we hypothesize that it may act as a fulcrum during flexion and extension of the head because it is located between the apical ligament and superior crus of the cruciform ligament. Anteroposterior open-mouth digital radiographs revealed the location of the TOL with respect to the upper two cervical vertebrae. Future research should investigate the radiologic characteristics of the TOL using magnetic resonance imaging.

A new technique for seeding chondrocytes onto solvent-preserved human meniscus using the chemokinetic effect of recombinant human bone morphogenetic protein-2

Many investigators are currently studying the use of decellularized tissue allografts from human cadavers as scaffolds onto which patients’ cells could be seeded, or as carriers for genetically engineered cells to aid cell transplantation. However, it is difficult to seed cells onto very dense regular connective tissue which has few interstitial spaces. Here, we discuss the development of a chemotactic cell seeding technique using solvent-preserved human meniscus. A chemokinetic response to recombinant human bone morphogenetic protein-2 (rhBMP-2) was observed in a monolayer culture of primary chondrocytes derived from femoral epiphyseal cartilage of 2-day-old rats. The rhBMP-2 significantly increased their migration upto 10 ng/ml in a dose-dependent manner. When tested with solvent-preserved human meniscus as a scaffold, which has few interstitial spaces, rhBMP-2 was able to induce chondrocytes to migrate into the meniscus. After a 3-week incubation, newly-formed cartilaginous extracellular matrix was synthesized by migrated chondrocytes throughout the meniscus, down to a depth of 3 mm. These findings demonstrate that rhBMP-2 may be a natural chemokinetic factor in vivo, which induces migration of proliferative chondrocytes into the narrow interfibrous spaces. Our results suggest a potential application of rhBMP-2 for the designed distribution of chondrocytes into a scaffold to be used for tissue engineering.

Keloids Show Regional Distribution of Proliferative and Degenerate Connective Tissue Elements

Keloids, formed by the deposition of excessive scar tissue, are characterised by the presence of thick hyalinised collagen bundles. Contradictory reports about keloid morphology include: hyperproliferation of dermal fibroblasts versus few fibroblasts; rich as opposed to poor vascularisation; dilated against occluded microvessels; distinct collagen nodules versus their absence, and elevated levels of types I and III collagen as opposed to no change when compared with normal dermis. This study attempted to clarify the controversies concerning keloid morphology by examining entire keloids and establishing baseline histological characteristics. Keloidal specimens from 32 patients were processed and comprehensively examined using light microscopy. The results of the study showed that keloids comprise many distinct regions, categorized as the zone of hyalinising collagen bundles, fine fibrous areas, area of inflammation, zone of dense regular connective tissue, nodular fibrous area and area of angiogenesis. The microvascular supply to each of these regions was impaired and features of degeneration and necrosis of keloid fibroblastic cells and microvessels were ubiquitous. Impairment of the healing stage of chronic inflammation, inefficient healing by fibrosis, multiple and exaggerated phases of vascular and fibrous granulation and remodelling stages manifest in keloid formation. The uneven distribution of cells may be due to the generation of traction forces by keloid cells. These forces also modify DNA and protein synthesis, leading to an overproduction of extracellular matrix components. This study provides a structured basis for future ultrastructural and immunocytochemical research of keloids and other fibroproliferative disorders.

Entwicklung des Ligamentum capitis femoris und der gleichnamigen Arterie

A morphological study concerning the development of the ligamentum teres and its artery was performed by investigating 300-600 microns thick epoxy resin impregnated sections through the hip joints of human fetuses and newborn children. In addition, the hip joints were macroscopically studied in three fetuses and in two newborn children. After photographical documentation the ligamenta teretes of these hips were processed into paraffin section. Within the ligamentum teres areas of different structures can clearly be distinguished during fetal development. The subsynovial layer consists of dense connective tissue containing numerous large cells. The major central portion of the ligament is formed by dense regular connective tissue. The blood vessels of the ligament are always surrounded by a layer of loose connective tissue. Adipose tissue firstly starts to spread in the postnatal period mainly occurring around the vessels. In the newborn child dense connective tissue is most abundant within the ligamentum teres. Thus it is considered to be especially strong. The femoral capitis artery is already present in 9 week-old fetuses. In 13 week-old fetuses branches of the femoral capitis artery enter the femoral head through cartilaginous channels and continuously maintain within the femoral head during further development. With the growing age of the fetuses the number of branches of the femoral capitis artery increases. Anastomoses between the cartilaginous channels of the femoral capitis artery and the medial and lateral circumflexal femoral artery can be found neither prenatally nor postnatally.