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Notes: Abstract. The purpose of this study was to investigate the effect of 2 growth factors, platelet-derived growth factor-BB (PDGF-BB) and insulin-like growth factor-1 (IGF-1) alone or in combination, on the adherence of human periodontal ligament fibroblast (PDL) to tetracycline HCI (TTC) conditioned and non-conditioned periodontally involved root surfaces. There were 80 root dentine chips from 80 patients, ranging from 35 to 70 years of age, each with one periodontally involved tooth requiring extraction. A root dentine chip was obtained from the subgingival surface opposite to the periodontal pocket of each extracted tooth. The dentine chips were randomly distributed into one of 8 groups. In group 1, PDL Fibroblasts were cultured and allowed to attach on the dentine surface. In group 2, PDL fibroblasts were cultured on a PDGF-BB pre-treated dentine surface and in group 3, they were cultured on a IGF-1 pre-treated dentine surface. In group 4, PDL fibroblasts were cultured on a dentine surface pretreated with a combination of PDGF-BB and IGF-1. In group 5, PDL fibroblasts were cultured and allowed to attach on the TTC conditioned dentine surfaces. In groups 6 and 7, surface of dentine chips were conditioned with TTC and then were treated with PDGF-BB or IGF-1 respectively, followed by placement of PDL fibroblast and cultured. In group 8, dentine surfaces were conditioned with TTC and then pre-treated with a combination of PDGF-BB and IGF-1 before the fibroblasts were cultured. After 24 h of incubation, the media was removed and samples were fixed and processed for SEM at magnifications of ×34, ×750, ×2000. Photographing and evaluation of samples was performed at ×750 in which fibroblast adherence was measured by counting cells within a standard test area. The results of the non-TTC conditioned root surfaces demonstrated a significant increase in fibroblasts adherence in the PDGF-BB and combination PDGF-BB/IGF-1 treatment groups (groups 2, 4) when compared to the control (group 1) as well as the TTC control (group 5). The combination of PDGF-BB/IGF-1 (group 4) did not significantly improve the adhesion of cells compared to PDGF-BB alone (group 2), but did significantly improve adhesion when compared to IGF-1 alone (group 3). There were no significant differences in cell morphology between the growth factor groups (groups 2, 3, 4) and control (group 1). In general, the cells demonstrated a fiat, stellate-shaped morphology. The results of the TTC conditioned root surfaces, showed a statistically significant increase of cellular adherence in the PDGF-BB group (group 6) when compared to the TTC control (group 5), similar to the non-TTC group (group 2). However, the morphology of the cells in groups 5, 6, 7, and 8 demonstrated generally a rounded or oval shape with only an occasional cell exhibiting a flat form, in the experimental system of this study, the inclusion of PDGF-BB on the surface of dentine chips increased the number of adhering PDL cells, and the addition of TTC conditioning had little effect except to change the morphology of adhering cells.

Notes: The purpose of this study was to determine the effect of surgical induction of anterior disk displacement (ADD) on type-Ill. VI and IX collagens of the rabbit craniomandibular joint (CMJ) tissues using an immunohistochemical technique. The right joint was exposed surgically, all discal attachments were severed except for the posterior discal attachment (bilaminar zone). The disk was then repositioned anteriorly and sutured to the zygomatic arch. The left joint served as a sham-operated control. Ten additional joints were used as non-operated controls. Deeply anesthetized rabbits were perfused with 2% buffered formalin 2 weeks (10 rabbits) or 6 weeks (10 rabbits) following surgery. The articular disk, bilaminar zone, mandibular condyle and articular eminence were excised. The last two were decalcified in EDTA. All tissues were then sectioned at 10 um in a cryostat. Sections were incubated with monoclonal antibodies directed against type-Ill. VI or IX collagens. Following incubation in the appropriate FITC-fabelled secondary antibodies, all sections were studied under the fluorescence microscope. The results showed a reduction in immunostaining for type-VI and IX collagens in the condylar cartilage, disk and articular eminence at 2 weeks, followed by an increase in their immunostaining at 6 weeks and the appearance of a de novo type-Ill collagen in the condylar cartilage and the articular eminence. It is concluded that surgical induction of ADD in the rabbit CMJ leads to alterations in its type-III. VI and IX collagens.

Notes: Several studies have shown that anterior disk displacement (ADD) of human temporomandibular joint (TMJ) can lead to cellular and extracellular alterations in the disk proper, bilaminar zone (BZ), condyle, articular eminence and synovial membrane. Due to lack of an animal model for this disease, it is not known whether the mechanical displacement of the disk could lead to the observed histopathological changes. The purpose of this experiment was to investigate the histopathological changes that occur in the rabbit craniomandibular joint (CMJ) following surgical induction of ADD. The right CMJ was exposed surgically and the discal attachments were severed except for the BZ attachments. Then the disk was displaced anteriorly and sutured to the zygomatic arch. The left joint served as surgical control. The CMJs were removed after 24 h, 1 week, 2 weeks or 6 weeks and stained with H&E or modified Masson stain. The results showed neovascularization, cell clustering and fibrillation of the displaced disk. The BZ showed marked fibrosis. The condyle showed subchondral hemorrhage and fibrosis followed by osteoarthritic changes in the articular cartilage. The articular eminence showed chondrocytic clustering and an increase in the amount of chon-droid bone. Synovial membrane exhibited marked hyperplasia. We concluded that surgical induction of ADD in the rabbit CMJ leads to cellular and extracellular alterations in the disk proper, BZ, condyle, articular eminence and synovial membrane similar to those described previously in human ADD. It appears that the mechanical trauma resulting from ADD could lead to a cascade of reparative and degenerative changes of the affected joints similar to those described for osteoarthritis.

Notes: Background:  Results from our previous studies suggest that surgical induction of anterior disk displacement (ADD) in the rabbit craniomandibular joint (CMJ) leads to histopathological alterations consistent with osteoarthritis. In addition, molecular changes in collagens and glycosaminoglycans (GAGs) were observed using immunohistochemistry. The purpose of the present study was to further characterize those molecular changes in collagens and GAGs using immuno-electron microscopy.Methods:  The right joint of 15 rabbits was exposed surgically and all discal attachments were cut except for the posterior attachment (the bilaminar zone). The disc was then repositioned anteriorly and sutured to the zygomatic arch. The left joint was used as a sham-operated control. Ten additional joints were used as non-operated controls. Mandibular condyles were removed 2 weeks following surgery and processed for light and immuno-electron microscopy using colloidal gold-labeled antibodies against collagen type I, II, VI and IX and against keratan sulfate, chondroitin-4 and -6-sulfate, and link protein.Results:  Light microscopic results showed osteoarthritic changes. Immuno-electron microscopy of osteoarthritic cartilage demonstrated a decline in type II collagen, the abnormal presence of type I collagen and loss of type VI and IX collagens. Quantitative colloidal gold immuno-electron microscopy confirmed the depletion of keratan sulfate, chondroitin-4 and -6-sulfate, and link protein in osteoarthritic cartilage.Conclusion : Anterior disk displacement leads to molecular alterations in both the collagen and the proteoglycans of rabbit condylar cartilage characteristic of osteoarthritis in other synovial joints. These alterations are consistent with loss of the shock absorber function of the cartilage and injury of the underlying bone.

Notes: Summary A cholinesterase localization method and a monoamine histofluorescence technique were used to locate nerve fibres in regenerating rat submandibular gland autografts. Experimental rats had a portion of one submandibular gland excised and cut into small fragments which were autografted immediately into the middle one-thrid of the tongue. Control rats had a portion of one submandibular gland removed and discarded, and their tongues were sham-operated. Seven to ten weeks later, the rats were killed and the tongues were removed, frozen and sectioned in a cryostat. A light microscopical study of the tongue sections subjected to the cholinesterase technique showed that the submandibular gland autografts contained many nerve fibres that exhibited cholinesterase activity. These cholinesterase-positive nerve fibres were distributed throughout the autografts. The fibres were associated with the numerous duct-like structures and the less numerous acini. In addition, ultraviolet illumination of tongue sections after treatment with a glyoxylic acid mixture revealed histofluorescent monoaminergic nerves within the autografts. These fibres were less prominent than the cholinesterase-positive fibres and appeared to run primarily along blood vessels within the autografts. The results suggest that autonomic nerves are present within regenerating submandibular gland autografts.

Notes: Scanning electron microscopy (SEM) of the surface tubercles of a specialized mechanoreceptor found within the head of Elaphe obsoleta lindheimeri indicates that the tubercle consists of a craterlike structure with a peg emerging from its center. After removal of the outer keratinized layers of the epidermis, the SEM discloses a replicate tubercle on the underlying alpha keratin layer. Over 6000 tubercles were found within a single snake. The mechanoreceptors were more densely concentrated on anterior scales, and their number appears to be species specific so that they are more concentrated in snakes with smaller heads than in those with larger ones.

Notes: Summary In concert with studies of the effects of various pharmacologic inhibitors of corticosteroidogenesis on adrenocortical morphology, U-8113, an analog of amphenone B, was administered daily to Sprague-Dawley rats for 7, 14, 21 or 30 days. The primary morphological responses involved increases in adrenal weight, width of zona fasciculata, width of zona reticularis, intracellular lipids, mitochondrial size, mitochondrial vacuolation and crystalline-like inclusions, small coated vesicles, lysosomes, autophagic vacuoles and cholesterol ester clefts. In particular, the increases in lysosomes, coated vesicles and autophagic vacuoles containing morphologically altered mitochondria were considered reflective of mechanisms designed to maintain cellular integrity amidst functional impairment. Lipid analysis revealed marked increases in cholesterol esters and phospholipids, supportive of morphological observations. When permitted a 14 day recovery period following either 14 or 30 days of inhibitor therapy, most fine structural alterations and lipid derangements were diminished, and the cells approximated normal parameters.

Notes: This morphologic study compares the regenerative response in submandibular gland (SMG) autografts placed in the tongues of previously sympathectomized rats to autografts placed in tongues of sham-sympathectomized rats. We hypothesized that sympathectomy would alter the process of cellular proliferation and inhibit cytodifferentiation in regenerating SMG autografts. Either 1 week, or 8 to 11 weeks following the SMG autografting procedure, the rats were sacrificed and their tongues were removed and sectioned in a cryostat. Frozen tissue sections containing the SMG autografts were either reacted for cholinesterase activity, treated with a glyoxylic acid mixture to induce histofluorescence, or stained for histologic examination. In addition, 3H-thymidine labeled and unlabeled cells were counted in autoradiographs of 1-week autografts, and these counts were used to calculate labeling indices. The 1-week SMG autografts from both the sympathectomized and the sham-sympathectomized rats were similar in histologic appearance, and neither group of autografts contained cholinesterase-positive or monoaminergic nerve fibers. The 8- to 11-week autografts from sympathectomized and sham-sympathectomized rats contained cholinesterase-positive fibers, but monoaminergic fibers were present in the autografts only from the sham-operated rats. Acinar cells were observed in one-third of the 8- to 11-week autografts of both the sympathectomized and the shamsympathectomized rats. This finding suggests that sympathectomy did not preclude cytodifferentiation in the autografts. The autoradiographic data revealed no statistically significant difference between the mean labeling indices of the 1-week autografts from the sympathectomized and sham-sympathectomized rats, which suggests that sympathectomy also did not alter the level of cellular proliferation in the autografts.

Notes: The lacunar cell layer in rat snake epidermis contains many characteristic intracellular vacuoles. The lipid nature of these large round vacuoles was demonstrated by histochemical and ultrastructural investigations. Rhomboid-shaped clefts, similar to cholesterol ester clefts, were observed in proximity to the vacuoles.

Notes: Autologous SMG fragments were implanted in tongues of male rats which were sacrificed 15-20 min, 24 hr, 72 hr, 1 week, or 8 weeks after implantation. The tongues were excised, fixed, and processed for light and electron microscopy. In addition, some rats were injected with [3H]-thymidine 1 hr before sacrifice and the labeling indices (L.I.) of the salivary epithelial and interstitial cells were calculated. Twenty-four hours after implantation, SMG autografts showed massive central necrosis with some acini and ducts surviving at the periphery of the lobules. There was marked infiltration of the autografts with neutrophils and macrophages. Also the basal laminae surrounding the necrotic acini and ducts remained intact. The morphology of the autografts after 72 hr was similar to that after 24 hr except that there was additional necrosis and acini and ducts could no longer be identified in the autografts. By 1 week after implantation, the autografts showed lobular morphogenesis, ductal branching, and revascularization. At this time, the regenerating salivary epithelium appeared undifferentiated with no evidence of secretory granules. The L.I. of interstitial and ductlike structures showed significant increases over control values at 1 week after implantation, and then declined toward control levels by 3 weeks after implantation. By 8 weeks after implantation, there was evidence of acinar and striated ductal cytodifferentiation in two autografts. The results emphasize the potential of SMG autografts to regenerate subsequent to severe tissue necrosis.