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Transforming growth factor alpha (TGF-alpha) is a polypeptide regulator of cell growth produced by many malignant tumors. It stimulates osteoclastic resorption in bone organ culture and osteoclast-like cell formation in marrow culture. To determine whether tumor production of TGF-alpha can cause hypercalcemia in vivo, we used Chinese hamster ovarian (CHO) cells transfected with the human TGF-alpha gene (TCHO), which stably express and secrete TGF-alpha. We used nontransfected CHO cells as controls (CCHO). TCHO and CCHO were inoculated intramuscularly into one hindlimb of nude mice and grew as local solid tumors. After 4 weeks of TCHO tumor growth, plasma ionized calcium (Ca2+) increased to reach 1.48 +/- 0.03 mM (mean +/- SEM), whereas mice bearing similarly sized CCHO tumors and non-tumor-bearing mice (NTB) remained normocalcemic (normal range for Ca2+, 1.15-1.30 mM). Plasma TGF-alpha was undetectable by an ELIFA assay in all NTB mice, was markedly increased in all TCHO mice (5.75 +/- 0.78 ng/ml), and was slightly increased in CCHO mice (0.50 +/- 0.22 ng/ml). Quantitative bone histomorphometry showed a prominent increase in osteoclastic bone resorption in TCHO mice. These data suggest that TGF-alpha is a mediator of hypercalcemia and increased osteoclastic bone resorption in tumors that produce it in sufficient quantity.

A single application of recombinant human transforming growth factor beta 1 (rhTGF-beta 1) adjacent to cartilage was found to induce bone formation in rabbit ear full-thickness skin wounds. At doses that optimally promote soft tissue healing, 25-100 ng rhTGF-beta 1 per wound caused osseous tissue formation starting 21 days after wounding to reach a peak incidence and area of bone formation at day 42. Bone formation was followed by active remodeling, resulting in lower incidence and area of bone formation at days 56 and 70. The early phase of bone formation was located overlying the cartilage and involved perichondrial cells that appeared to differentiate directly into osteoblasts forming bone matrix without a cartilage precursor. Cartilage was replaced with bone at later time points. rhTGF-beta 1 was able to increase the ratio of osteoblasts to osteoclasts lining the trabecular surface of bone and thus increase the net amount of bone formation. The present studies suggest a potential therapeutic role for rhTGF-beta 1 in hard tissue repair.

Aseptic loosening of glenoid components is a common problem associated with total shoulder arthroplasty. A new glenoid design aimed at improving fixation outcomes was compared with conventional keeled glenoids in weight-bearing canine shoulders. Radiographic, histologic, and mechanical tests were performed at 3 postoperative intervals (0, 3, and 6 months). The uncemented pegged glenoid achieved bone ingrowth around the peg flanges in each case. This result was confirmed histologically and radiographically. Mechanical results indicated that mean fixation strength increases significantly between 0 and 3 months after surgery and remains strong through 6 months. In contrast, conventional keeled glenoids were found to have partial or complete radiolucent lines around the keel in each instance, and mechanical testing demonstrated that mean fixation strength weakens significantly between 0 and 3 months after surgery and remains weak through 6 months. These results show that stem design changes can improve implant fixation. A cementless fluted peg stem was superior to a conventional cemented keel design in achieving osseous integration and fixation in a weight-bearing animal model. (J Shoulder Elbow Surg 2001;10:140-8.)

We investigated the migration of rat calvaria osteoblast populations on poly(α-hydroxy ester) films for up to 14 days to determine effects of substrate composition and culture conditions on the migratory characteristics of osteoblasts. Initial osteoblast culture conditions included cell colonies formed by seeding a high (84,000 cells/cm2) or low (42,000 cells/cm2) density of isolated osteoblasts on the polymer films, and bone tissue cultures formed by plating bone chips directly on the substrates. High density osteoblast colonies cultured and allowed to migrate and proliferate radially on 85:15 poly(DL-lactic-co-glycolic acid) (PLGA) films, 75:25 PLGA films, and tissue culture polystyrene controls demonstrated that the copolymer ratio in the polymer films did not affect the rate of increase in substrate surface area (or culture area) covered by the growing cell colony. However, the rate of increase in culture area was dependent on the initial osteoblast seeding density. Initial cell colonies formed with a lower osteoblast seeding density on 75:25 PLGA resulted in a lower rate of increase in culture area, specifically 4.9 ± 0.3 mm2/day, versus 14.1 ± 0.7 mm2/day for colonies seeded with a higher density of cells on the same polymer films. The proliferation rate for osteoblasts in the high and low density seeded osteoblast colonies did not differ, whereas the proliferation rate for the osteoblasts arising from the bone chips was lower than either of these isolated cell colonies. Confocal and light microscopy revealed that the osteoblast migration occurred as a monolayer of individual osteoblasts and not a calcified tissue front. These results demonstrated that cell seeding conditions strongly affect the rates of osteoblast migration and proliferation on biodegradable poly(α-hydroxy esters). © 1996 John Wiley & Sons, Inc.

Background: The purpose of the present study was to create an effective bone-graft substitute for the treatment of a diaphyseal nonunion. Methods: A standardized nonunion was established in the midportion of the radial diaphysis in thirty mongrel dogs by creating a three-millimeter segmental bone defect (at least 2 percent of the total length of the bone). The nonunion was treated with implantation of a carrier comprised of poly(DL-lactic acid) and polyglycolic acid copolymer (50:50 polylactic acid-polyglycolic acid [PLG50]) containing canine purified bone morphogenetic protein (BMP) or recombinant human transforming growth factor-β (TGF-β1), or both, or the carrier without BMP or TGF-β1. Five groups, consisting of six dogs each, were treated with implantation of the carrier alone, implantation of the carrier with fifteen milligrams of BMP, implantation of the carrier with 1.5 milligrams of BMP, implantation of the carrier with fifteen milligrams of BMP and ten nanograms of TGF-β1, or implantation of the carrier with ten nanograms of TGF-β1. At twelve weeks after implantation, the radii were examined radiographically and the sites of nonunion were examined histomorphometrically. Results: We found that implantation of the polylactic acid-polyglycolic acid carrier alone or in combination with ten nanograms of TGF-β1 failed to induce significant radiographic or histomorphometric evidence of healing at the site of the nonunion. The radii treated with the carrier enriched with either 1.5 or fifteen milligrams of BMP showed significantly increased periosteal and endosteal bone formation on histomorphometric (p < 0.05) and radiographic (p < 0.02) analysis. Conclusions: Bone formation in a persistent osseous defect that is similar to an ununited diaphyseal fracture is increased when species-specific BMP incorporated into a polylactic acid-polyglycolic acid carrier is implanted at the site of the nonunion. TGF-β1 at a dose of ten nanograms per implant did not induce a similar degree of bone formation or potentiate the effect of BMP in this model. Clinical Relevance: The biodegradable implant containing BMP that was used in the present study to treat diaphyseal nonunion is an effective bone-graft substitute.

A successful tissue engineering method for bone replacement would imitate natural bone graft by providing the essential elements for new bone formation using synthetic scaffolds, osteogenic cell populations, and bone induction factors. This is a study of the suitability of various formulations of poly(DL-lactic-co-glycolic acid) (PLGA) foams to provide a tissue conducting scaffold in an ovine model for bone flap fabrication. Three formulations were used of different copolymer ratio and molecular weight. Porous wafers of PLGA were stacked into rectangular chambers (volume 4 cm3) enclosed on five sides. Some chambers also contained autologous morcellized bone graft (MBG). The chambers were inserted with the open face adjacent to the cambium layer of the periosteum in rib beds of seven sheep and harvested after 8 weeks in vivo. Gross and histologic examination of the resulting tissue specimens demonstrated molded units of vascularized tissue generally conforming to the shape of the chambers and firmly attached to the periosteum. Polymer degradation appeared to occur by varying degrees based on polymer formulation. New bone formation was observed only in areas containing MBG. There was no evidence of significant inflammatory reaction or local tissue damage at 8 weeks. We conclude that a PLGA foam scaffold is (1) an efficient conductor of new tissue growth but not osteoinductive, (2) contributes to the shape of molded tissue, and (3) biocompatible when used in this model. Further studies are warranted to develop practical methods to deliver bone induction factors to the system to promote osseous tissue generation throughout the synthetic scaffold.

Recent advances in understanding the biology of fracture healing and the availability of specific macromolecules has resulted in the development of novel treatments for injuries to bone. Fibroblast growth factor-2 or basic fibroblast growth factor (4 mg/ml), a potent mitogen, and hyaluronan (20 mg/ml), an extracellular matrix component, were combined into a viscous gel formulation intended for direct, percutaneous injection into fresh fractures. In an experimental primate fracture model, a bilateral 1-mm-gap osteotomy was surgically created in the fibulae of baboons. A single direct administration of this hyaluronan/fibroblast growth factor-2 formulation to the defect site significantly promoted local fracture healing as evidenced by increased callus formation and mechanical strength. Radiographic analysis showed that the callus area was statistically significantly larger at the treated sites than at the untreated sites. Specimens treated with 0.1, 0.25, and 0.75 ml hyaluronan/fibroblast growth factor-2 demonstrated a 48, 50, and 34% greater average load at failure and an 82, 104, and 66% greater energy to failure than the untreated controls, respectively. By histologic analysis, the callus size, periosteal reaction, vascularity, and cellularity were consistently more pronounced in the treated osteotomies than in the untreated controls. These results suggest that hyaluronan/fibroblast growth factor-2 may provide a significant advance in the treatment of fractures.

Advances in periodontics with respect to disease activity, microbiology and immunology have demonstrated the multifactorial nature of periodontal diseases. This serves to underscore the need for an ideal animal model for periodontal research. Non-human primates are most similar to man in comparison to other animal models. The baboon is an Old World monkey that has infrequently been used in periodontal research. Periodontal exams were accomplished on 116 baboons (Papio anubis, P. cynocephalus) ages 5 to 30 years with one baboon year being roughly equivalent to 3 to 4 human years. The study population consisted of 29 males and 87 females. Clinical parameters including probing depth, attachment level, mobility, plaque index and gingival index were collected. Radiographs were taken on 25 animals and correlated to clinical findings. Results showed a significant increase in mean probing depth and mean attachment level with age (p = 0.0001). Disease prevalence and severity were not significantly different between genders. Mobility was uncommon; however, the prevalence and severity of furcation involvement increased with age. Radiographs suggested horizontal and isolated vertical bone loss. Plaque and gingival indices were at sustained high levels for all age groups and showed a statistically significant increase with age. Some baboons were found to develop a naturally-occurring periodontitis that increased in severity with age. This primate may be a suitable model for studies in human periodontal disease.

Cytokines play a major role in tissue destruction caused by autoimmune dysregulation. In Sjögren's syndrome (SS) patients, salivary glands are the target organs for autoimmune tissue damage. In the present study, reverse transcriptase-polymerase chain reaction (RT-PCR) was used to look for cytokine mRNA expressed in SS salivary glands. Focus score was used to determine the severity of the lesions. Cytokine production in supernatants of the salivary gland cell culture was measured by enzyme-linked immunosorbent assay (ELISA). Immunohistochemical staining was used to identify the local presence of transforming growth factor beta (TGF-beta). Interleukin (IL)-2, IL-6, and IL-10 mRNA were expressed in moderate to severe SS salivary gland lesions. TGF-beta mRNA was constitutively expressed in normal and SS salivary glands. In SS salivary gland cell cultures, IL-6 and IL-10 proteins were produced. TGF-beta production was reduced in high focus score SS glands. Normal and minimally involved SS salivary gland ductal epithelium and acinar cells were found to produce TGF-beta by immunostaining. In conclusion, an excess production of IL-2, IL-6, and IL-10 and a reduced production of the immunosuppressive cytokine, TGF-beta, may be responsible for the progression of the salivary gland lesion in SS. Specific immunotherapy can now be designed based on mechanisms to correct this cytokine imbalance and benefit patients with autoimmune diseases, such as SS.

This study tested the efficacy of alendronate, a bisphosphonate, in reducing alveolar bone loss caused by experimental periodontitis in cynomolgus monkeys. Periodontitis was initiated in adult monkeys by ligating mandibular molar teeth at the cementoenamel junction (CEJ) and subsequently inoculating the ligature with Porphyromonas (Bacteroides) gingivalis. Controlateral, homologous non-ligated teeth served as controls. Animals received, intravenously, either saline (placebo) or alendronate at 0.05 or 0.25 mg/kg every 2 weeks for 16 weeks. After the animals were sacrificed, coronal sections through mandibular molars were subjected to histomorphometrical analysis. No overt side-effects were observed in any of the animals participating in this study. In placebo-treated animals, ligation and inoculation resulted in significant bone loss both at the CEJ and at the furcation. Alendronate at 0.05 mg/kg significantly reduced bone loss associated with the experimental periodontitis at both sites. In contrast, the dose of 0.25 mg/kg was ineffective in attenuating alveolar bone loss in the furcation area and only slightly effective in preventing it at the CEJ area. The results of the histomorphometric analysis correlate closely with those of the radiographic analysis of the same experiment. These data indicate that alendronate could reduce the loss of alveolar support associated with periodontitis and suggest that bisphosphonates, by virtue of their significant inhibitory action on osteoclasts, may become a treatment modality in the battle against alveolar bone destruction during periodontal disease.

The proximal poles of five patients with presumed avascular necrosis of the scaphoid, mostly the result of nonunion, were analyzed histologically for true, pathologically confirmed avascular necrosis of bone. Each specimen was reviewed both qualitatively by an experienced bone pathologist and quantitatively with the use of a computerized image analysis system. Avascular necrosis was found to be variable from one specimen to another as well as within each specimen. Midcentral levels showed a statistically significant greater degree of avascular necrosis than either adjacent palmar or dorsal zones. Both viable and nonviable areas of avascular bone were found in an unpredictable, irregular (patchy) distribution, often in direct apposition to one another. It is apparent from this study that random biopsy alone cannot accurately predict the histologic status of the entire specimen; the clinician must rely on other methods to determine scaphoid viability.

This report describes a case of subpontic osseous hyperplasia that occurred in the posterior mandible of a healthy 67-year-old woman. The two hard masses, which were removed from beneath a fixed partial denture that was placed 35 years ago and spanned the lower left first premolar and the first and second molars, consisted of normal viable dense cortical bone. Only 30 cases of this phenomenon defined as a slow-growing, benign osseous proliferation occurring on the crest of the alveolar ridge beneath the pontic of a fixed partial denture have been described in the literature. Possible causes, including genetic programming, functional stimulus, and mild chronic irritation are discussed, as well as rationale for treatment of this anomaly.

Osteoporosis is a morbid clinical condition of ill-defined pathogenesis in which there is progressive and inexorable loss of skeletal mass rendering bone increasingly vulnerable to fracture after minimal trauma. In addition to osteoporosis, loss of bone from the oral skeleton or the maxillofacial complex also significantly impacts the health and quality of life of patients, most often the elderly. Oral bone loss most commonly results from periodontal disease, resorption of alveolar ridges following tooth extraction, or combinations of both. Periodontal disease is caused in part by bacterial pathogens adherent to the dentition and other oral surfaces. There is now significant interest in the interrelationship of systemic osteoporosis to both periodontal disease and other forms of oral bone loss. This is in part because both diseases, while extracting significant morbidity and mortality, are often studied in isolation, thus their relationship is unknown. This paper will focus on the development of an animal model which is uniquely suited for the study of both osteoporosis and oral bone loss. Malluche et al., 1992, have conducted and reviewed many of the most widely used animal models for research in osteoporosis, along with their associated advantages and disadvantages. Data from their studies and those of Roach et al., 1989, and others have shown, however, a need for animals which develop both systemic and oral bone loss and thus can serve as models to expand our knowledge of the relationship of both diseases. In this paper we report data from studies of the baboon which show the development of ovarian dysfunction with advancing age, along with loss of systemic and oral bone mass similar to the osteoporosis syndrome of humans. These data support the utility of the baboon as a model of age related systemic and oral bone loss.

Bisphosphonates have been shown to increase bone mass in estrogen-deficient patients by inhibiting osteoclast activity. The purpose of this study was to measure clinical and radiographic effects of a bisphosphonate on periodontitis development in monkeys. Twenty-seven (27) adult cynomolgus monkeys were studied. After quarantine, baseline data were obtained including plaque index, gingival index, clinical probing depth measurements, and intraoral radiographs. Standardized radiographs were analyzed for quantitative changes in bone density using a computer assisted densitometric (CADIA) system. Animals were divided into 3 groups to receive 1 of the 3 treatment agents; these agents consisted of two levels of the test drug (alendronate) and a saline placebo. Agents were injected in the saphenous vein of the lower leg every 2 weeks for 16 weeks. One week after the initiation of treatment agent injections, mandibular right molars and premolars were ligated with 3-0 silk sutures to induce periodontitis. Ligated teeth were also inoculated with Porphyromonas gingivalis to insure a significant etiologic challenge. Nonligated homologous teeth served as controls. Clinical measurements and radiographs were repeated at 8 and 16 weeks after ligation. The bisphosphonate at a concentration of 0.05 mg/kg significantly retarded the progression of periodontitis as measured by bone density changes. The higher level dose of the test drug did not differ from placebo with respect to loss of bone density. Clinical indices were not affected significantly by the test drugs. Drugs that alter bone metabolism may offer a new approach to the treatment of periodontal disease.

A novel implantable device, the analytic bone implant, was used in order to establish a model for studies of bone-healing and the evaluation of factors that augment the process, such as transforming growth-factor beta (TGF-beta). This device was implanted into the tibiae of four baboons. After healing, bone was removed from the center chamber. Recombinant human TGF beta-1 was then delivered to the core of the device. After twenty-two days of healing, the device was disassembled and the newly formed bone was removed from the core of the implant for histomorphometric analysis. An analysis of the bone revealed a substantial effect of TGF-beta on osteoblastic activity and proliferation compared with that seen in control and placebo groups. However, despite increased osteoblastic activity, trabecular bone volumes at twenty-two days were equivalent among the groups. The number of osteoclasts and the erosion of the surface were also increased, although not significantly so. Substantial endochondral formation of bone was seen in the supraperiosteal tissues directly over the implants that contained TGF-beta but not over the implants in the control and placebo groups. These data demonstrate the utility of this bone-implant model for studies of bone-healing with minimally invasive methods. In addition, use of the device provided the first in vivo data on the effects of TGF-beta at an intermediate (twenty-two-day) time-point in the healing process in a non-human primate.

Trabecular bone deficiency causes a dilemma at surgery in a variety of clinical situations, including trauma, tumor resection, and reconstruction. A synthetic material to replace trabecular bone would be biocompatible, provide temporary mechanical strength to the reconstructed region, and serve as a scaffold upon which new bone could grow (i.e., osteoconduction). In addition, it should serve as a carrier for osteoinductive biomolecules, degrade into nontoxic materials that the body can excrete via normal metabolic pathways, and allow the new bone to remodel along lines of local stress. A particulate filled composite based on an unsaturated linear polyester was designed as a candidate material for this application. The components are mixed with a monomer that cross links the double bonds of the unsaturated polyester. Degradation occurs via hydrolytic degradation of the backbone polymer's ester linkages. This strategy of prepolymer synthesis via condensation polymerization in the laboratory followed by cross linking the unsaturated prepolymer via radical polymerization at surgery offers design flexibility. The radical polymerization allows curing during surgery to facilitate reconstruction of various shaped defects. The laboratory synthesis of the prepolymer allows alterations of its composition and physical properties to effect desired properties in the resulting composite. This study investigates the effect of several composite material formulations on the in vitro mechanical properties and the associated in vivo histologic characteristics of the resulting material. The prepolymer molecular weight, presence of a leachable salt, and amount of cross linking monomer had strong effects on the resulting strength and modulus of the composite. These strengths were on the order of 5 MPa, a magnitude appropriate for consideration of the material as a temporary trabecular bone substitute. The in vivo studies in a rat proximal tibia model demonstrated progressive growth of new bone against the receding surface of the degrading material, and ingrowth of new bone trabeculae into the interior of the degrading specimen. The specimen was also well integrated with the surrounding bone, with no internal fibrosis. There was an absence of a foreign body inflammatory response to the presence of this material over a 5-week time span. This material may thus be an attractive candidate for temporary replacement of trabecular bone, facilitating both osteoconduction and osteoinduction.

A non-union model was established in the mid-part of the radial diaphysis in dogs. The non-union was treated with operative implantation of a carrier (guanidine-extracted, demineralized bovine bone or a polylactic acid polymer), alone or in combination with fractions that had been enriched in bone morphogenetic protein. All sites of treatment were examined radiographically and histomorphometrically at twelve weeks after implantation. Guanidine-extracted, demineralized bovine bone, alone or combined with fifteen milligrams of canine bone morphogenetic protein, failed to induce any healing of the non-union. When polylactic acid alone had been implanted, a small amount of reparative new bone was found in the defect at three months. When polylactic acid combined with fifteen milligrams of canine bone morphogenetic protein had been implanted, a significant increase in new bone formation was seen (p less than 0.03), compared with that seen in control animals. Trabecular bone bridged the gap between the proximal and distal fragments in all four specimens from the dogs that had received that treatment. In contrast, when polylactic acid combined with bovine bone morphogenetic protein had been implanted, significant reparative new bone was not found in the defect at three months.

Osseous hemangiomas of the facial bones are rare lesions, with most cases occurring in the maxilla and mandible. Reported cases in the zygoma are sparse. Two cases of zygomatic hemangiomas with widely differing presentations are reported. One case in a neonate required surgery to prevent fatal hemorrhage, and the other in an adult required correction of a cosmetic deformity. Each patient presented with a second congenital anomaly. Therapeutic problems associated with these lesions and their management are discussed.

static renal cell carcinoma: A case report and literature review. J Urol 135:1005, 1986 24. Miyamoto R, Helmus C: Hypernephroma metastatic to the head and neck. Laryngoscope 83:898, 1973 25. Flocks RH, Kadesky MC: Malignant neoplasms of the kidney: An analysis of 353 patients followed five years or more. J Urol 79:196, 1958 26. Kent SE, Majumdar B: Metastatic tumours in the maxillary sinus: A report of two cases and a review of the literature. J Laryngol Otol 99:459, 1985 27. Talley RW, Moorhead EL, Tucker WG, et al: Treatment of Metastatic Hypernephroma. JAMA 207:322, 1969 28. Fujita T, Asano H, Naido Y, et al: Anti-tumor effects of human lymphoblastoid interferon on renal cell carcinoma. J Urol 139:256, 1988 29. Von Roemeling R, Rabatin JT, Fraley EE, et al: Progressive metastatic renal carcinoma controlled by continuous 5-ftnoro2-deoxyuridine infusion. J Urol 139:259, 1988 30. Meyer I, Shklar G: Malignant tumors metastatic to mouth and jaws. Oral Surg 20:350, 1965 31. Braun-Falco O, Lukas I: Hypernephrommetastasen der Haut und Ihre Behandlungsmoglichkeiten. Jautarzt 22:452, 1971 32. Debain JJ, Poulain H: Les metastases ethmoidales des cancers du rein. Nouv Presse Med 25:1716, 1972 33. Levine H: The sphenoid sinus: The neglected nasal sinus. Arch Otolaryngol 104:585, 1978 34. Barrs DM, McDonald TJ, Whisnant JP: Metastatic tumors to the sphenoid sinus. Laryngoscope 89:1239, 1979 35. Ferlito A, Recher G, Polidoro F: Nasal metastasis from primary cancer of the kidney. J Laryngol Otol 93:1115, 1979 36. Kathuria S, Molnar Z, Reyes CV: Renal cell carcinoma presenting as epistaxis. J Surg Oncol 14:153, 1980 37. Akdas A, Kirkali Z, Ruacan S, et al: Unusual metastases of renal cell carcinoma. Urol Int 42:316, 1987 38. Som PM, Norton KI, Shugar JMA, et al: Metastatic hypernephroma to the head and neck. AJNR 8:l 103, 1987 39. Seijas Rosales T, Estelles Ferriol E, Dalmau Galofre J: Maxilar superior como localizacion de metastasis tumoral: A proposito de un caso. Anales ORL Iber Am 16:357, 1989 40. Old RA, Malins T, Ward-Booth PR: Vascular metastatic renal carcinoma of the maxilla: Report of two cases. Int J Oral Maxillofac Surg 19:106, 1990 41. Kennel P, Piller P, Herman D, et al: Metastases orl des tumeurs de Grawitz. Ann Otolaryngol 108:126, 1991 42. Fandella A, Anselmo G, Maccatrozzo L, et al: Epistaxis in renal carcinoma. Scand J Urol Nephrol 26:89, 1992

Bone sialoprotein (BSP) is a major non-collagenous extracellular matrix protein in bone and other mineralized connective tissues. BSP is synthesized and secreted by bone-, dentin- and cementum-forming cells. In this study we hypothesized that BSP may be also involved in enamel formation through its postulated role in matrix mineralization. In situ hybridization with cRNA probes for rat and hamster BSP, respectively, showed strong mRNA signals in ameloblasts actively synthesizing enamel matrix in developing incisors. However, no hybridization signals were observed at an earlier developmental stage when bell-shaped molar tooth germs were being formed. Immunohistochemical analysis of tooth tissues from transgenic mice harboring a 2.7 kb rat BSP promoter ligated to a luciferase reporter gene revealed strong staining for luciferase in the enamel epithelium of the developing tooth germ. Interestingly, BSP expression was also observed in epithelial cells of an ameloblastoma. The neoplastic epithelial nests and cords demonstrated strong mRNA signals to the human BSP probe while the connective tissue stroma showed only a background level of silver grains. Immunostaining also showed deposition of BSP by the odontogenic cells of the tumor. These results demonstrate that BSP is expressed by the enamel-forming epithelium of developing teeth, suggesting a possible role for BSP in enamel formation and its subsequent mineralization. Expression of the BSP gene in ameloblastomas is consistent with the expression of BSP by the enamel epithelium and also with the expression of BSP by neoplastic tissues, suggesting a possible role in tumorigenesis.

The medial collateral ligaments of 1 8 New Zealand rabbits were surgically detached from bone. In one knee, the ligament was repaired using a biodegradable suture anchor composed of a co-polymer of lactic and glycolic acid. The contralateral medial collateral ligament was not repaired. Animals were sacrificed at 4, 8, and 1 2 weeks after the operation, and the knee that had the ligament repair was compared with the contralateral control knee. All knees were tested manually tested for stability to valgus stress and then prepared for histologic examination. Medial collateral ligaments repaired using the biodegradable suture anchor demonstrated stability to valgus stress and anatomic healing at the bone-tendon junction. Resorption of the implant was virtually complete by 1 2 weeks. All specimens demonstrated less inflammatory reaction to the suture anchor than to the attached Vicryl suture. This contrasts with the control group, which was grossly unstable and demonstrated scarring in this nonanatomic position. These results demonstrate efficacy of this particular material of biodegradable implant and justify further investigative efforts.

Purpose Giant cell lesions of the oral cavity are a well recognized entity. However, the histogenesis of these lesions is still the subject of controversy, with support for both histiocyte/macrophage and osteoclast origins being found in the literature. This study evaluated a set of peripheral giant cell lesions (PGCLs) and central giant cell lesions (CGCLs) for characteristics of both cell types to address this dilemma. Materials and Methods Detection of histiocyte/macrophage characteristics was accomplished immunohistochemically by evaluating for markers specific for this cell type, namely α-1-antichymotrypsin (1-ACT) and factor XIIIa antibodies. Detection of osteoclast characteristics made use of the fact that osteoclasts possess a unique enzyme, tartrate-resistant acid phosphatase, which can be appreciated by histochemical procedures. Results A large percentage of the multinucleated cells stained with the 1-ACT (38.08% in PGCLs and 15.84% in CGCLs), while only isolated cells stained for factor XIIIa (1.20% PGCLs, 0.99% CGCLs). Isolated stromal cells also were stained. Virtually all multinucleated cells reacted with the tartrate-resistant acid phosphatase stain (99.26% PGCLs, 98.34% CGCLs), as did a number of the mononuclear stromal cells. Conclusions This study supports the contention that GCLs of the oral cavity may arise from precursor cells related to the granulocyte/macrophage line, and may originate from mononuclear cells that express markers for both macrophages and osteoclasts.

Objective— This study evaluates the efficacy of the Palmaz balloon expandable intraluminal stent in the trachea and mainstem bronchi of normal dogs. Study Design— Effects of the stent were evaluated by physical examination, thoracic radiography, respiratory tract fluoroscopy and endoscopy, tracheal diameter measurement, postmortem examination, and airway histomorphometry. Animals or Sample Population— Ten normal beagle dogs. Methods— Stent size was estimated from thoracic radiographs in awake dogs. Group I dogs (n = 4) had two stents placed: one in the thoracic trachea (TT) plus a randomly chosen mainstem bronchus (MB). Group II dogs (n = 3) had stents placed in the MB (one stent), TT (one stent), and mid- or proximal cervical trachea (CT) (one or two stents). Three dogs were used as sham-operated controls (group III). Temperature, pulse, respiration, and cough were measured twice daily. Dogs were evaluated at 21 and 49 to 56 days after stent placement, euthanatized, and tissues were collected for histomorphometric analysis of stent integration and epithelial pathology. Results— Mean tracheal diameters of awake (10.5 ±1.7 mm) and anesthetized dogs before stent implantation (13.9 ± 2.0 mm) were significantly different (P

This study was done to determine the histologic etiology for the linear black signal seen on magnetic resonance imaging at the site of proximal femoral fractures. No previous satisfactory explanation for this black line exists in the literature. To determine the pathologic etiology of this linear black signal, the magnetic resonance imaging appearances of osteotomies and fractures of proximal femora were correlated with gross and histologic appearances in 12 freshly frozen porcine hips. In phase 1, a unilateral femoral neck osteotomy was performed in 1 hip, and a sham operation was performed on the contralateral hip. The radiologist was able to easily determine the site and side of the osteotomy using magnetic resonance imaging. In phase 2, the remaining 8 femoral specimens were stressed using the 1125 Instron Materials Testing Machine in a compression mode. In the 8 specimens, 4 fractures were created that were visible on magnetic resonance imaging and plain radiographs; 2 fractures were apparent only on magnetic resonance images, and 2 specimens did not have fractures identified by plain radiographs or magnetic resonance images. Gross and microscopic analysis of the specimens confirmed the magnetic resonance imaging findings in all 8 cases (6 fractures and 2 nonfractures). Histologic evaluation showed trabecular impaction at the 6 fracture sites corresponding to the linear black signal on magnetic resonance images. No edema or hemorrhage was present in these postmortem specimens. The authors conclude that the low signal band seen with proximal femoral fractures is produced by impaction of the trabecular bone and is not the result of perifracture edema or hemorrhage.

Acquired cholesteatoma is associated with an intense inflammatory reaction with resultant tissue and bone destruction. Cytokines are molecules released by inflammatory cells at the site of infection and are potent mediators of inflammation and the immune response. Five cytokines, tumor necrosis factor-alpha, transforming growth factor-beta 1 and 2, and interleukin-1 and 6, were immunolocalized in human cholesteatoma epithelium and subepithelial stroma, with greater intensity of staining compared with noninflamed external auditory canal skin. Increased interleukin-6 activity in cholesteatoma epithelium and stroma correlated significantly with the presence of ossicular and bony erosion and granulation tissue noted intraoperatively. Transforming growth factor-beta 2 activity in cholesteatoma epithelium correlated significantly with bony erosion at surgery. Additionally, transforming growth factor-beta 1 activity in cholesteatoma epithelium correlated significantly with increased length of disease. Tumor necrosis factor-alpha, interleukin-1, and interleukin-6 appear to be involved in the inflammation and resultant remodeling associated with cholesteatoma. We hypothesized a protective function of transforming growth factor-beta 1 and 2 in the presence of cholesteatoma. The antiinflammatory and osteoclast and keratinocyte inhibitory actions of the transforming growth factor-beta s could potentially slow the proliferation and resultant tissue destructiveness associated with cholesteatoma.

Clinical situations that require techniques to fill defects of bone are common in the surgical care of Orthopaedic patients. The options currently available to the surgeon are autograft bone (bone from the same person), allograft bone (bone from a deceased donor), and bone cement. Each of these options has a mix of desirable and undesirable properties, and the choice of one of them necessarily involves some degree of compromise. We have been developing a novel, degradable, polymeric composite biomaterial to function as an alternative to the currently available options. The design goals for this biomaterial are that the material be sterilizable without loss of its mechanical and biological properties, available to the surgeon in the sterile operating field on short notice, moldable such that it can fill irregularly shaped defects, harden over a time span of ten to fifteen minutes, provide the reconstructed skeletal region with mechanical properties of the same order of magnitude as those of the bone it replaces, degrade over a period of weeks to months, be replaced by new bone, and maintain a specified minimum mechanical strength during the period of degradation and new bone growth. In this study we asked two questions. First, would the material maintain a minimum compressive strength greater than 5 Megapascals (MPa) and a minimum compressive modulus greater than 100 MPa over a twelve week period in a simulated body fluid environment? Second, would the material degrade in vivo in a rat proximal tibia model?

Recent data have suggested that there may be a relationship between osteoporosis and oral bone loss. Both diseases are major public health problems of enormous magnitude, but their relationship is poorly understood. This is due to their complex pathogenesis and the fact that coexisting periodontal disease, loss of the dentition, site-specific variability in anatomy and bone density, as well as aging and many other factors complicate the development and progression of bone loss relative to each. The focus of this article is to review the characteristics of animals that are suited for studies of the relationship of osteoporosis and oral bone loss to better understand their relationship.

Three cases of chondrosarcoma involving the jaws are presented, one in the maxilla and two in the mandible. The salient points of clinical presentation elucidated by this series of cases are that a widened periodontal ligament space is present in chondrosarcomas as well as in osteosarcomas, and that a slowly increasing diastema may be the earliest clinical sign. The most important lesson to be learned from the histopathology is that one should not accept a diagnosis of a benign cartilaginous tumor of the jaws. Treatment of these lesions should consist of wide surgical excision and consideration of adjunctive or palliative radiotherapy, especially in the maxilla. It should also be noted that recurrences may develop 10 to 20 years later, and follow-up should be lifelong.

Bone biopsy is an established diagnostic and investigative procedure that allows direct visualization of bone cells and structure and provides an indirect measure of bone turnover. It is widely used in management of metabolic bone disease and to explain any unclear biochemical abnormality affecting bone metabolism; it should become more widely used as its availability increases. Bone biopsy defines a variety of mineralization defects caused by fluoride, diphosphonates, and aluminum, and it provides unique insight into bone loss with age and with osteoporosis. It is necessary for evaluating rapidly progressive osteoporosis and it can be particularly useful for differentiating osteoporosis from osteomalacia. Although osteomalacia is often the result of decreased dietary vitamin D, there are recognized risk factors, such as previous gastric surgery or chronic renal disease. Nonetheless, clinical findings in osteomalacia are often rather subtle, and there may be few biochemical findings. Hence, if the patient is an elderly woman, and therefore also at risk for osteoporosis, the distinction can be difficult. Imaging studies are not likely to be helpful, since both disorders lead to decreased bone mass, usually at the same sites. The diagnostic criteria for osteomalacia are increased extent of osteoid surfaces, increased osteoid thickness, and thickened osteoid seams, in conjunction with a decreased calcification rate (as calculated by tetracycline labeling) and decreased calcification fronts. Osteoid volume alone is not an adequate diagnostic criterion, because it may also be increased in Paget's disease and hyperparathyroidism. Finally, biopsy is a valuable means to assess the effect of potential therapeutic agents on bone and bone cells.(ABSTRACT TRUNCATED AT 250 WORDS)

We have developed an improved model for studying in vivo nonsurgical treatment of head and neck cancer. In situ oral cavity implantation has been documented, but its natural history is not defined. In light of this, an improved model is described. Forty-two nude mice had tumor cells from one of two established laryngeal squamous cell carcinoma cell lines implanted into the floor of the mouth. The tumor mass was measured and followed. When the tumor burden was great enough to cause cachexia, the animals were killed and submitted for microscopic examination. Pulmonary metastases were noted in 44%, bone invasion in 80%, angioinvasion in 76%, and soft tissue invasion in 96% of the animals. Growth characteristics in the head and neck have not been documented in previous models. Our model not only exhibits the locally invasive activity typically associated with malignant neoplasms, but also closely parallels the results of clinical studies examining the percent of end stage patients and autopsies with pulmonary metastases. Therefore, this model should open the way for more meaningful in vivo studies of nonsurgical treatment modalities for both local and metastatic tumor foci in head and neck cancer.

The purpose of this study was to determine if antibiotic-supplemented bone allografts (ASBA) would enhance healing and reduce infection in chronic osteomyelitis. Intramedullary injection of Staphylococcus aureus was used to create osteomyelitis in the tibia of New Zealand white rabbits. Twenty-one days postinoculation, the animals were randomly assigned to one of the following six treatment groups: 1. debridement of the infected tibia; 2. debridement + bone graft; 3. debridement + bone graft + gelatin powder; 4. debridement + bone graft + gelatin powder supplemented with antibiotics; 5. debridement + gelatin powder supplemented with antibiotics; and 6. no surgical intervention. The debrided material was cultured for identification of microorganisms. All groups received cephalothin sodium, 100 micrograms/kg subcutaneously every 12 hours for 21-days. At time of death the tibia were assessed to determine the degree of healing. Radiographs, bacterial cultures and specimens for histologic study were obtained. Qualitative grading demonstrated a significant difference between groups (P less than .001). Groups (4 and 5) receiving local antibiotic supplementation demonstrated improved healing compared with the remaining groups. However, there was no difference between groups 4 and 5. Bacteriologic culturing indicated the greatest reduction in colony-forming units of S aureus in the postsacrifice graft sites to be in groups 4 and 5. Histologic findings paralleled qualitative assessment of healing of the gross specimens. The results of this study suggest that local antibiotic supplementation of graft preparations may be useful for treatment of chronic osseous infection.

Using autoradiographic techniques, tritiated estrogen-receptor complex intranuclear labeling was identified in certain laryngeal tissues of four aged female baboons; no complex labeling was found in the control animal. Three significant findings were felt to be derived from this study. One, surface epithelium of the larynx had essentially no estrogen-receptor activity. Two, all tissues of mesenchymal origin, especially lamina propria, muscle, dense connective tissue, and fat had consistently high levels of nuclear localization of the labeled estrogen. The binding affinity seemed to be the highest at the anterior commissure and the immediate anterior subglottic space. Three, there was a high level of receptor binding in laryngeal cartilage and perichondrium. Since the activated hormone-receptor complex modulates gene expression to alter the amount of mRNA, sex steroids have a direct regulatory effect upon the target cell and, perhaps through an induction process, can exert an indirect effect upon adjacent tissues. It is postulated that since the larynx is a sexually dimorphic organ, the sex steroids and their receptors may play a role in altered phonation during aging and possibly in the development of laryngeal neoplasms and other diseases. Therefore, hormonal manipulation may play a future role in the therapy of laryngeal diseases. This study represents the first demonstration of estrogen receptors by specific anatomic location in the primate larynx with significant localization in the mesenchymal tissues but not in the epithelial tissues.

A modified approach to the treatment of two patients with oral mucous membrane pemphigoid, using an adaptation of a custom fluoride carrier, is described. The method provided for occlusive topical steroid therapy, overcoming many of the obstacles to such treatment for oral lesions. Response was excellent, with no adverse local or systemic effects. Further clinical trials to determine the applicability of this form of therapy in the treatment of patients with a number of infectious, ulcerative, and vesiculobullous oral diseases appear warranted.

A quantitative autoradiographic immunocytochemical study was performed in which the nuclear uptake and retention of 3H-estradiol (3H-E2) by luteinizing hormone (LH) and prolactin (PRL) cells was examined in 19-21-year-old baboons. 3H-E2 concentrating cells were found in all of the three lobes of the pituitary in varying percentages (38.7%, pars distalis; 17.1%, pars intermedia; 6.3%, pars nervosa). Approximately 80% of PRL cells and nearly 100% of LH cells were labeled. A count of the number of silver grains over nuclei revealed a marked variation of the accumulation of 3H-E2 by LH cells and to a lesser extent in PRL cells. These results suggest functional heterogeneity among LH and PRL cells. The present results are discussed in relation to the physiological state of old animals.

Two patients with Sjögren's syndrome (SS) who subsequently developed malignant B-cell lymphomas are reported in detail. The first patient had both benign- and malignant-appearing lymphoid infiltrates on the same submandibular gland specimen and was successfully treated with combined chemotherapy and irradiation. The second patient developed cutaneous lymphoid infiltrates difficult to diagnose by light microscopy but containing a monoclonal IgM-Kappa population revealed by immunoperoxidase staining and immunoglobulin gene rearrangement studies. Her lesions resolved rapidly and completely on cyclophosphamide, recurred rapidly when this drug was discontinued, and resolved again on a second course of cyclophosphamide which is currently maintained at 50 mg daily. Both patients are doing well without recurrence two and three years after initial treatment. This clinical experience is presented to emphasize: (1) the clinical use of molecular biologic techniques to define the earliest appearance of malignant transformation in Sjögren's syndrome, and (2) the successful outcome that can be achieved with prompt institution of appropriate treatment. The phenomenon of lymphoma development in SS is discussed with regard to immunoregulatory abnormalities predisposing to malignancy in the setting of autoimmune disease.

An in-depth review of the literature on Garre's osteomyelitis has been presented, along with an additional case, in a 7-year-old Caucasian boy with an unusual presentation. In most instances, the periosteal proliferation is in response to an attenuated infection associated with a periapical inflammation, a recent extraction, or an infected or traumatized operculum. In this case the diagnosis was complicated by an absence of clinical signs, indicating the presence of an attenuated infection. While the appearance of the lesion on occlusal and periapical radiographs was consistent with a clinical diagnosis of Garre's osteomyelitis, conditions such as Ewing's sarcoma and others could not be eliminated on the basis of the clinical and radiographic findings alone. In this instance a definitive diagnosis could be made only after biopsy.

Eight patients with previously placed silicone temporomandibular joint (TMJ) implants were operated on again. Excised tissues from in and around the joint were histologically evaluated. In one case, a parotid lymph node was also examined. All specimens revealed fragmented, amorphous, refractile, but nonbirefringent, irregularly spherical foreign material consistent with fragmented silicone. Granulomatous inflammation and multinucleated giant cells were associated with the silicone material. These findings demonstrated that silicone may not be a totally inert material and that its biomechanical properties are not ideal for use in the TMJ.

Curvularia lunata is a saprobic dematiaceous mould that resides primarily in soil (Ellis, 1966). Reports of human disease caused by this organism are rare but include: endocarditis, brain abscess, skin infections, onychomycosis, keratitis, pneumonia, disseminated disease, mycetoma, allergic bronchopulmonary disease, and one case of sinusitis. Since 1983, we have encountered five cases of paranasal sinusitis due to C. lunata. None of the patients suffered from known immunologic disorders or underlying debilitating diseases. These five cases are presented and the literature of human phaeohyphomycosis caused by Curvularia spp. is reviewed.

Intravascular angiomatosis, also known as Massons' lesion, is a relatively uncommon, although important, tumor because it clinically mimics such benign lesions as mucocele, pyogenic granuloma, and hemangioma, as well as malignant neoplasms such as angiosarcoma and Kaposi's sarcoma. More important is the potential for misdiagnosis at the histological level that poses a significant problem to those unfamiliar with this lesion. This article reviews the literature on perioral intravascular angiomatosis and presents five additional cases.

Clinical observations for 5 ½ years and a postmortem examination, including radiographic and microscopic evaluation, showed a mandibular staple bone plate functioned well for a 78-year-old patient in compromised health.

Young adult, white New Zealand rabbits underwent either sham surgical procedures or discectomy. In the animals that underwent discectomy, either reinforced silicone or polytetrafluoroethylene-aluminum oxide (PTFE-Al2O3) implants were placed in the glenoid fossa. During gross sectioning, the silicone implants could be easily displaced from the specimen, while the PTFE-Al2O3 implants were firmly anchored. Histologically, fragmentation of the implants was seen in the silicone group; 21.4% of the implants placed were torn. Foreign body giant cell reactions reached a peak after eight weeks. Associated fibrosis and foreign body giant cell reactions were seen, resulting in a thickened capsule and resorption of the condyle and articular fossa. In the PTFE-Al2O3 group there was marked osteoclastic activity, with resorption and severe degenerative changes in both the condyle and glenoid fossa. The foreign body giant cell reaction was severe at all time intervals and increased with time. Tearing of the implant was observed in 46.2% of the joints. These results indicate a need for further evaluation of these materials as disc replacements in humans.

A soft agar cloning assay was used to culture 158 specimens of head and neck tumors. Fifty-seven (36%) tumors were successfully cloned, 56 (35%) specimens failed to grow, and 45 (29%) were contaminated. There was no correlation of growth or cloning efficiency with the age of the patient, stage of the disease, degree of histologic differentiation, previous exposure to radiation therapy or chemotherapy, or subsequent survival. Sufficient cells were available to perform one to six (median, 2) chemosensitivity tests (total of 81) on specimens from 31 patients. Using 30% or less in vitro survival as the criterion for chemosensitivity, four patients were sensitive to one or more drugs. Only one of these patients received the same drug tested in vitro, and this tumor proved to be resistant. The cloning assay has not yet proved useful in predicting chemosensitivity in individual patients because of technical difficulties (low percentage of successful growth and high contamination rates).

A 55-year-old male patient with no significant medical history or systemic physical findings was found, on routine dental examination, to have an oral Candida albicans infection. The condition failed to clear completely after 21 days of nystatin therapy. A 5-day course of clotrimazole was then initiated. Complete clearing of all signs of candida infection occurred in 48 hours, but the infection recurred by the twentieth day of follow-up. A 14-day regimen was then prescribed. Again, the condition cleared in 48 hours, and at the 6-month follow-up all signs of candida involvement, including cultures and smears, remained negative. As no reports of the use of clotrimazole vaginal tablets in oral candidiasis clinically refractory to nystatin therapy were found in the literature of the last 11 years, it was thought that this case was of significant interest.

The immune cell products interleukins 1 alpha and -beta, which stimulate osteoclast activity in vitro, are among the most potent bone resorbing factors so far described. Although it appears likely that these cytokines are involved in regulation of trabecular bone turnover, nothing is known of their effects on extracellular fluid calcium concentration. In this report, we show the effects of 72-hr subcutaneous infusions of interleukins 1 alpha and -beta on plasma calcium and bone morphology in mice. Both interleukins 1 caused a marked dose-dependent increase in the plasma calcium. In higher doses, which cause the animals to die, the plasma calcium fell preterminally. Quantitative histomorphometry of bone sections showed evidence of increased numbers of osteoclasts and bone resorption surfaces. The effects were similar to those obtained with infusions of parathyroid hormone. These data suggest that in addition to its potential influence on trabecular bone volume, interleukin 1 may also modulate extracellular fluid calcium homeostasis under conditions in which it is produced excessively.

Certain uncommon systemic infections may be present with head and neck manifestations either initially or during the course of the disease. A high index of suspicion is required on the part of the otolaryngologist with the subsequent procedures leading to the appropriate diagnosis. The manifestations of infectious diseases such as erysipelas, histoplasmosis, rabies, tetanus, botulism, and cysticercosis must be understood by the head and neck specialist. For successful management, many of the infections require prompt identification and initiation of therapy. Airway maintenance, ventilatory support, and medical chemotherapy may be required.

A retrospective analysis of 18 cases of extramedulary plasma-cytoma (EMP) was done to characterize the type of immuno-globulin being synthesized by the neoplastic cells. The immunoperoxidase stain can be performed on previously fixed tissue and offers a means of predicting the likelihood of progression to multiple myeloma (MM). Tumors producing lgG make up the majority of cases of EMP in the literature and only 9% have progressed to MM. Smaller numbers of tumors producing other immunoglobulin classes have been studied, but it is clear that their prognosis is much more grave.