Arthroscopic gel-type autologous chondrocyte implantation presents histologic evidence of regenerating hyaline-like cartilage in the knee with articular cartilage defect.

PURPOSE: To investigate the clinical, radiological, and histological results of arthroscopic gel-type autologous chondrocyte implantation (GACI) in treating chondral defects of the knee. METHODS: This study prospectively examined five males and five females with a mean age of 40.3 ± 10.3 years who underwent arthroscopic GACI between March 2012 and February 2013. The gel comprised a mixture of 1 ml of fibrinogen plus 0.1-0.2 ml of thrombin. The mean size of chondral defect was 2.9 ± 1.2 cm2 (range 1.2-5.4 cm2). International knee documentation committee (IKDC) subjective score, knee injury and osteoarthritis outcome score (KOOS), knee society score, and visual analog scale (VAS) for pain were assessed preoperatively and during regular follow-up examinations performed for up to 5 years postoperatively. Serial magnetic resonance imaging was performed for up to 2 years after the surgery to observe healing, using the modified magnetic resonance observation of cartilage repair tissue (MOCART) score. In eight patients, second-look arthroscopy was performed at 1 year after the implantation to assess the status of treated cartilage, and a portion of regenerated cartilage was harvested for histologic evaluation. RESULTS: The mean VAS score (p = 0.045), IKDC subjective score (p = 0.041), KOOS pain (p = 0.025), KOOS activities of daily living (p = 0.048), and KOOS quality of life (p = 0.029) showed significant improvement at 5 years after the surgery. The modified MOCART evaluation showed that the scores were 59.5 ± 29.4 and 85.0 ± 8.0 at 12 weeks and 2 years after the operation, respectively. Histologic examination demonstrated a mean regenerated cartilage thickness of 3.5 ± 0.8 mm and a mean Oswestry score of 8.2 ± 1.8. Immunohistochemistry analysis showed that the expression of collagen type II was more evident and more evenly distributed than collagen type I in regenerated cartilage. There was a significant correlation between Oswestry score and change in VAS scale from postoperative 2-5 years. CONCLUSIONS: Arthroscopic GACI produces satisfactory clinical and radiologic outcomes, and histologic evaluation confirms sufficient regeneration of hyaline-like cartilage that correlates with improved symptoms. Therefore, it is an acceptable, minimally invasive, and technically simple option for the restoration of cartilage defects of the knee. LEVEL OF EVIDENCE: IV.

Histological analysis of hyalinised keloidal collagen formation in earlobe keloids over time: collagen hyalinisation starts in the perivascular area.

Keloids grow and do not regress. They are characterised histologically by hyalinised keloidal collagen (HKC). HKC amounts vary, and the mechanism by which they form is unclear. To clarify how HKCs form and whether their formation associates with specific clinical features, we studied the histological findings of earlobe keloids and compared them with respective clinical features. A total of 50 earlobe keloids from 43 patients were used for histological analysis of keloid size (mm2 ), HKC area (mm2 ) and HKC area ratio (%). As a result, keloid durations ranged from 3 months to >13 years. Early-stage keloids exhibited little HKC and a tendency for the HKCs to locate in perivascular regions. In later-stage keloids, the HKCs were extremely interconnected and formed a thick bitten donut-shaped region. HKC area ratios correlated positively with keloid duration (r2 = 0·58, P<0·05). HKC area ratios and keloid durations did not correlate with keloid sizes. These patterns of HKC formation and growth may explain why local therapies, which effectively remove fibroblasts and accumulated collagen but not HKCs, are ineffective in older keloids. Keloids should be promptly treated after diagnosis, and older keloids with extensive HKCs may require surgical excision followed by radiotherapy.

Effect of Enoxaparin Sodium on Experimentally-Induced Myringosclerosis in Rats.

OBJECTIVE: To evaluate the effectiveness of enoxaparin sodium (ES) on experimentally-induced myringosclerosis in rats. MATERIALS AND METHODS: Twenty Wistar albino-type rats weighing up to 250-300 g each were randomized into four groups containing five rats each and were then bilaterally myringotomized. The control group (n=5) received intratympanic serum physiologic injections, whereas ES2 (n=5), ES4 (n=5), and ES6 groups (n=5) received intratympanic ES of 2000 IU, 4000 IU, and 6000 IU, respectively, for 10 days after myringotomy. Rats were sacrificed at 60 days after intratympanic application and were then prepared for histopathologic evaluation. RESULTS: As for tympanic membrane hyaline degeneration, there were statistically significant differences among the control, ES2, ES4, and ES6 groups (p<0.05). As for fibrosis formation on tympanic membranes, a statistically significant difference was observed among the control and study groups; however, although not statistically significant, the formation of fibrosis was slowed down in the ES2 and ES4 groups compared with the control group. The control and study groups did not show any significant difference for calcification, hyperemia, and tympanic membrane thickening (p>0.05). CONCLUSION: Although our study and control groups comprised limited number of animals, and only one parameter demonstrated a statistically significant difference between the groups, ES may have an ameliorating effect on myringosclerosis induced by myringotomy in the tympanic membranes of rats. ES proved to be effective in the prevention of hyaline disc formation. Further studies should be conducted for better understanding of the effects of low-molecular-weight heparin (LMWH) (i.e., enoxaparin) on myringosclerosis.

Force distribution is more important than its intensity!

A common question about root resorption is raised in orthodontic practice: What is more important, the intensity of force or its distribution along the root, periodontal and alveolar structures? Diffuse distribution of forces applied to periodontal tissues during tooth movement tends not to promote neither extensive areas of cell matrix hyalinization nor significant death of cementoblasts that lead to root resorption. However, focal distribution or concentration of forces within a restricted area - as it occurs in tipping movements, even with forces of lower intensity - tend to induce extensive areas of hyalinization and focal death of cementoblasts, which is commonly associated with root resorption. In tipping movements, the apical regions tend to concentrate more forces in addition to wounding the cementoblasts due to the smaller dimension of their root structure as well as their cone shape. For this reason, there is an increase in root resorption. In the cervical region, on the other hand, the large area resulting from a large diameter and bone crown deflection tends to reduce the effects of forces, even when they are more concentrated, thus rarely inducing death of cementoblasts and root resorption.

Um questionamento comum sobre as reabsorções radiculares na prática ortodôntica: "O que é mais importante? A intensidade das forças aplicadas ou sua distribuição ao longo das estruturas radiculares, periodontais e alveolares?" A distribuição difusa das forças aplicadas sobre os tecidos periodontais durante o movimento dentário de corpo tende a não promover extensas áreas de hialinização da matriz extracelular, nem morte significativa de cementoblastos que levariam à reabsorção radicular. Porém, a distribuição focal ou concentração de forças - como nas inclinações, mesmo nas de menor intensidade - em uma área restrita tende a induzir áreas extensas de hialinização e morte focal de cementoblastos, associando-se mais comumente à reabsorção radicular. Nos movimentos de inclinação, as áreas apicais, por sua menor dimensão da estrutura radicular e sua forma cônica, tendem a concentrar mais ainda as forças e lesar cementoblastos, aumentando a frequência das reabsorções radiculares. Na região cervical, a maior área decorrente do maior diâmetro e a deflexão óssea da crista óssea tendem a reduzir os efeitos das forças, mesmo quando mais concentradas, muito raramente induzindo a morte de cementoblastos e reabsorções radiculares.

Compressive force induces VEGF production in periodontal tissues.

During orthodontic tooth movement, the activation of the vascular system in the compressed periodontal ligament (PDL) is an indispensable process in tissue remodeling. We hypothesized that compressive force would induce angiogenesis of PDL through the production of vascular endothelial growth factor (VEGF). We examined the localization of VEGF in rat periodontal tissues during experimental tooth movement in vivo, and the effects of continuous compressive force on VEGF production and angiogenic activity in human PDL cells in vitro. PDL cells adjacent to hyalinized tissue and alveolar bone on the compressive side showed marked VEGF immunoreactivity. VEGF mRNA expression and production in PDL cells increased, and conditioned medium stimulated tube formation. These results indicate that continuous compressive force enhances VEGF production and angiogenic activity in PDL cells, which may contribute to periodontal remodeling, including angiogenesis, during orthodontic tooth movement.

Histopathology of nonotosclerotic stapes fixations.

HYPOTHESIS: Different diseases without exact histopathologic classification can cause stapes ankylosis. BACKGROUND: Otosclerosis is a complex bone remodeling disorder of the otic capsule due to persisting measles virus infection and consecutive inflammatory reaction. In fact, clinical and demographic features of otosclerosis have reference to stapes ankylosis. In the clinical practice, otosclerosis and stapes ankylosis are incorrect synonyms. METHODS: Nonotosclerotic stapes footplates (n = 284) removed during stapedectomy were analyzed histologically. Otosclerosis was excluded during the histologic preselection (n = 437). Total RNA was extracted, and measles virus-specific reverse-transcriptase-polymerase chain reaction was performed. RESULTS: Nonotosclerotic stapes ankylosis was associated with total absence of measles virus RNA. Six main types of nonotosclerotic stapes fixations could be distinguished histologically: annular calcification (n = 152; 53.5%), globular fibrosis (n = 49; 17.25%), lymphocytic infiltration (n = 31; 10.9%), hemosiderosis (n = 22; 7.75%), granulomas (n = 17; 6%) and amyloidosis (n = 13; 4.6%). Fragmentation of nonotosclerotic stapes footplates was infrequent (7%) during stapes surgery. Only 1 floating footplate (0.35%) was reported. CONCLUSION: Two thirds of nonotosclerotic stapes footplates represented complete pathologic bone remodeling. Unlike otosclerosis, nonotosclerotic stapes fixations were characterized by basic histopathologic findings without organ specificity that can also be identified in case of different diseases. Prevalence of nonotosclerotic stapes ankylosis is approximately 30 to 40% among stapes fixation cases. The long-term prognosis and surgical considerations theoretically differ from those of otosclerosis.

Triple-phase dynamic MRI of intratumoral vessel density and hyalinization grade in uterine leiomyomas.

OBJECTIVE: Our purpose was to clarify the relationship between the tissue vascularity shown on triple-phase dynamic MRI and the number of intratumoral vessels and degree of hyalinization, which are two histopathologic changes in leiomyoma. SUBJECTS AND METHODS. The subjects were 10 premenopausal patients with 20 leiomyomas who had undergone surgery without preoperative gonadotropin-releasing hormone analogue treatment. Intratumoral vessel density was determined by the mean number of intratumoral vessels with at least one smooth-muscle layer in the optic fields magnified 100 times. Hyalinization grade was determined by the severity of hyalinization, histopathologically classified in three grades. The enhancement index (EI) of the leiomyoma was calculated using the formula EI(t) = [S(t) - S(0)] / S(0), where S(0) is the signal intensity on pre-enhanced T1-weighted images and S(t) is the signal intensity on each dynamic phase image (t = 20, 60, and 180 sec) [corrected]. The histopathologic parameters of intratumoral vessel density and hyalinization grade were compared with the enhancement indexes obtained from the triple-phase dynamic MRI. RESULTS: We found positive correlations between intratumoral vessel density and EI(60) and between intratumoral vessel density and EI(180) (in both cases, p = 0.0028 and r = 0.69). We found significant differences among the mean enhancement indexes for each hyalinization grade at all dynamic phases (p < 0.01). The leiomyomas with lower intratumoral vessel densities tended to show greater hyalinization. CONCLUSION: Our results showed that leiomyomas with only slight hyalinization or with abundant vessels were well enhanced, but the leiomyomas with severe hyalinization enhanced poorly.

Subchondral bone and cartilage disease: a rediscovered functional unit.

The role of subchondral bone in the pathogenesis of cartilage damage has likely been underestimated. Subchondral bone is not only an important shock absorber, but it may also be important for cartilage metabolism. Contrary to many drawings and published reports, the subchondral region is highly vascularized and vulnerable. Its terminal vessels have, in part, direct contact with the deepest hyaline cartilage layer. The perfusion of these vessels accounts for more than 50% of the glucose, oxygen, and water requirements of cartilage. Bony structure, local metabolism, hemodynamics, and vascularization of the subchondral region differ within a single joint and from one joint to another. Owing to these differences, repetitive, chronic overloading or perfusion abnormalities may result in no pathological reaction at all in one joint, while in another joint, these same conditions may lead to osteonecrosis, osteochondritis dissecans, or degenerative changes. According to this common etiological root, similar pathological reactions beginning with marrow edema and necrosis and followed by bone and cartilage fractures, joint deformity, and insufficient healing processes are found in osteonecrosis, osteochondritis dissecans, and degenerative disease as well.

The role of epithelium in the development, structure and function of the tissues of tooth support.

The roles of epithelium in the development, structure and function of the tissues of tooth support are reviewed. Epithelium is involved in initiating odontogenesis which includes the tissues of tooth support and this role is discussed. Particular attention is paid to Hertwig's epithelial root sheath and its participation in the formation of the hyaline layer on the root surface as well as its possible role in initiating the differentiation of cementoblasts. The possible functions of the epithelial cell rests are reviewed and it is concluded that as yet no function can be ascribed to them. Evidence for an increasing role for dental epithelium in tooth eruption is presented and the role of dental epithelium in establishing the dentogingival junction is discussed, with the conclusion drawn that this role temporary.

Deployment of extracellular matrix proteins in sea urchin embryogenesis.

The apical extracellular matrix of the sea urchin embryo, known as the hyaline layer (HL), is a multi-laminate organelle composed of at least 10 polypeptides. Although integrated into one ECM, HL proteins exhibit individual temporal and spatial dynamics throughout development. These molecules are stockpiled in the oocyte during vitellogenesis in at least four distinct vesicle populations. They are released onto the cell surface at fertilization in a specific order, and interact differentially with embryonic cells as development proceeds. Many experiments have suggested that the HL is vital for embryogenesis, but relatively little is known about the functions and interactions of its constituent molecules. The purpose of the present review has been to gather information on the basic characteristics of the known HL proteins together with data on their expression in the embryo, and where possible, their biological activities. Compiled, these observations may provide some insight into the workings of a uniquely embryonic organelle.

Protein-protein interactions and structural entities within the sea urchin extraembryonic matrix, the hyaline layer.

We have investigated the effects of a variety of experimental conditions on the structural integrity of the sea urchin extraembryonic matrix, the hyaline layer. Removal of Ca2+ resulted in the quantitative release of hyalin from isolated layers. Protein gel blot analyses indicated that, in the absence of Ca2+, hyalin was also quantitatively released from the layers surrounding 1-h-old embryos. However, no other polypeptides of the hyaline layer were released in significant amounts. The layers remaining after removal of hyalin were refractory to digestion with proteinase K and dissociated only in the presence of chaotropes. These results provide insights into the structural organization within the hyaline layer as well as the role of the embryonic cell surface in maintaining the structural integrity of this extraembryonic matrix.

Storage, ultrastructural targeting and function of toposomes and hyalin in sea urchin embryogenesis.

This study compares by immunogold labeling the ultrastructural localization of a hexameric 22S glycoprotein, called toposome, with that of hyalin in unfertilized eggs and cells of hatched sea urchin blastulae. Nearly all hyalin is present in the electron translucent compartment of the cortical granules and in the translucent non-cortical pigment granules. In the blastula both of these intracellular stores have vanished and hyalin now forms a broad band below the apical lamina. By contrast, in the egg toposomes are present on the surface, as well as stored in yolk granules and in the electron dense lamellar compartment of the cortical granules. In the hatched blastula, toposomes that have been modified by limited proteolysis in the yolk granules, are associated with the plasma membranes of all newly formed cells, while the toposomes originating from the cortical granules have been incorporated as unmodified 160 kDa polypeptides into an extracellular double layer enveloping the embryo on the outside of the hyaline layer. From evidence discussed in detail, we conclude that the extracellular toposomes rivet the apical lamina to the surface and underlying cytoskeleton of the microvilli, while the modified toposomes from the yolk granules are responsible for position specific intercellular adhesion as they are released to the surface of newly formed cells. We propose that all the material stored in yolk granules is utilized for the assembly of new membranes.

Distribution of elastic cartilage in the arytenoids and its physiologic significance.

An investigation of the distribution of the elastic cartilage in the arytenoids was performed on excised human adult and newborn larynges. The distribution of elastic cartilage in the arytenoids was investigated histologically in two serial sections: horizontal and coronal. The behavior of the elastic cartilage portion of the arytenoids was investigated histologically under the conditions of adduction and abduction. The results are summarized as follows. 1) Elastic cartilage is found not only at the tip of the vocal process but at the superior portion of the arytenoid cartilage from the vocal process to the apex. 2) This phenomenon is observed at birth. 3) The vocal process bends at the elastic cartilage portion during adduction and abduction. The sides of the arytenoids come into contact mainly at the elastic cartilage portion. 4) Elastic cartilage appears to play an important role in the physiologic functioning of the arytenoid.

Evidence for a dentin-derived inhibitor of macrophage spreading.

The ability of macrophages to spread in vitro on mineralized and non-mineralized tissues extracted with guanidium hydrochloride (GuHCl) was studied in order to establish morphologic evidence for an extractable inhibitor of macrophage spreading present within dentin. Macrophages were seeded onto dentin, demineralized dentin, predentin and hyaline cartilage extracted with different concentrations of GuHCl. Macrophages were also seeded onto unextracted tissues. The results were evaluated with scanning electron microscopy after varying incubation periods. Macrophages readily attached and spread on extracted and unextracted dentin, extracted demineralized dentin, predentin, and hyaline cartilage. Cells seeded onto unextracted demineralized dentin, predentin, and hyaline cartilage attached, but showed no signs of spreading. It was concluded that an extractable inhibitor of macrophage spreading is present in the organic, non-collagenous component of dentin. This inhibitor may be responsible for the resistance of predentin and dentin to resorption.

Activation of the vascular system: a main mediator of periodontal fiber remodeling in orthodontic tooth movement.

The behavior and role of blood vessels and blood-borne cells in the process of the remodeling of the periodontal ligament (PDL) incident to experimental tooth movement was studied in rats. Particular interest was focused on areas of tension and of pressure with frontal bone resorption but without overt hyalinization. An increase of vascular activity occurred in the above mentioned situations. Extensive breakdown of collagen was observed in pressure areas with frontal resorption and in areas of tension concomitant with vascular invasion. Two patterns of fiber and bone remodeling were seen in areas of tension: intense vascular activity within the periodontal membrane and intense vascular activity inside the alveolar bone. Macrophages occurred consistently near blood vessels both in areas of tension and in areas of resorption. These are multipotent cells that obviously influence the remodeling process.