Hajime Fuchihata

Histopathologic and radiographic findings of the simple bone cyst

OBJECTIVE The purpose of this study is to examine the correlation between histopathologic and radiographic findings and to discuss the cause of the simple bone cyst. STUDY DESIGN Histopathologically, we classified 53 simple bone cysts into two types. Type A has a connective tissue membrane and type B has a partially thickened wall with dysplastic bone formation. Radiographically, we evaluated the following: margin, radiolucency, or radiopacity, relationship with tooth apices, bucco-lingual bone expansion, and displacement of the mandibular canal. RESULTS Bone expansion and radiopacity were closely related to histopathologic findings although there was no correlation between the histopathologic findings and radiographic margin, relationship with tooth apices, and displacement of mandibular canal. Local recurrence was more likely to be observed in patients diagnosed as having type B than type A lesions. CONCLUSIONS Type A and type B bone cysts may have different causes. Cysts determined radiographically to be radiopaque, those diagnosed as type B histopathologically, and cysts that have been treated surgically should all be followed by radiographic examinations.

EFFECTS OF INTERLEUKIN-6 ON PROLIFERATION AND PROTEOGLYCAN METABOLISM IN ARTICULAR CHONDROCYTE CULTURES

Interleukin‐6 (IL‐6) levels are markedly increased in the synovial fluid of patients with rheumatoid arthritis or osteoarthritis. However, the effects of IL‐6 on proliferation and proteoglycan metabolism in articular cartilage are not known. We demonstrated here the effects of human recombinant (hr) IL‐6 on proliferation and proteoglycan metabolism in rabbit articular chondrocyte cultures. In vitro, these cells proliferated and produced abundant extracellular matrices. We found that 1–10ng/ml of hrIL‐6 inhibited proliferation to approximately 65% of control levels and suppressed colony formation induced by bFGF in soft agarose. The same concentration of hrIL‐6 depressed proteoglycan synthesis to approximately 60% of control levels. Moreover, hrIL‐6 significantly enhanced proteoglycan degradation induced by hrIL‐1β, although hrIL‐6 alone did not affect proteoglycan degradation. These findings suggest that IL‐6 is a negative regulator for chondrocyte proliferation and articular cartilage metabolism.

EFFECT OF X-RAY IRRADIATION ON PROLIFERATION AND DIFFERENTIATION OF OSTEOBLAST

Summary We exposed the osteoblast-like cell line, MC3T3-E1, to 1-to 10-Gy X-ray. Irradiation at doses of 5-Gy dose or more decreased the DNA content of cells at the proliferation stage, confluence, and post-proliferation stages. The alkaline phosphatase activity, conversely, was increased by irradiation, and the calcium content of irradiated cells was greater than that of nonirradiated. These findings suggest that irradiation induces terminal differentiation and calcification of osteoblasts.

Radiographic interpretation of so-called developmental defect of mandible

Ten cases of so-called development defect were detected on panoramic radiograms. One of them was bilocular, two were round, three were ovoid, and four were half-ovoid. Eight were in men and two were in women. These cystlike lesions are sometimes misdiagnosed as epithelium-lined cysts or benign tumors, such as ameloblastoma. For the detection of this kind of defect, panoramic radiography is available, and the lesion is differentiated from many cysts and tumors in the jaws by posteroanterior projection and occlusal films. From the published literature, some tendencies of age distribution and sex incidence were reviewed.

Inhibition of Chondrocyte Terminal Differentiation and Matrix Calcification by Soluble Factors Released by Articular Chondrocytes

Abstract. Chondrocytes do not undergo terminal differentiation in normal articular cartilage, whereas growth plate chondrocytes synthesize ALPase and induce matrix calcification terminally. Articular chondrocytes in osteoarthritic joints have been reported to express the terminal differentiation phenotypes, suggesting that terminal differentiation of articular chondrocytes is inhibited in normal joints. In the present study, we investigated the underlying inhibitory mechanism of the terminal differentiation in articular cartilage using a culture on type II collagen-coated dishes or a novel culture model on Millipore filters. ALPase activity increased from day 7 to day 8 in growth plate chondrocyte cultures on the collagen-coated dishes, but not in articular chondrocyte cultures. The ALPase expression of growth plate chondrocytes on the collagen-coated dish was completely inhibited when the same number of articular chondrocytes was mixed in the growth plate chondrocyte cultures. When articular chondrocytes or growth plate chondrocytes were maintained on Millipore filters held in 16-mm dishes, they started to synthesize ALPase. The ALPase expression of the chondrocytes on Millipore filters was inhibited by the presence of articular chondrocytes maintained on the bottom collagen-coated substratum in the same dishes. These results indicate that factors that diffused into the medium through the Millipore filters are involved in the inhibition of terminal differentiation. Since the conditioned medium from articular chondrocyte cultures did not affect the ALPase expression, it is considered that the soluble factors, which are continuously released from articular chondrocytes, are responsible for the inhibition of terminal differentiation.

Diagnostic imaging for a case of maxillary myxoma with a review of the magnetic resonance images of myxoid lesions

The findings of conventional radiography, computed tomography, and magnetic resonance imaging are reported for an odontogenic myxoma arising in the left anterior maxilla of a 50-year-old man. The magnetic resonance imaging characteristics of an intraosseous myxoma are described for the first time. The initial conventional radiographic examination disclosed a unilocular radiolucency with poorly delineated margins as typically seen in malignant tumors. Subsequently, acquired computed tomography scans displayed bony expansion and thinning of cortices on the labial aspect of the lesion. Magnetic resonance imaging revealed a well-defined, well-enhanced mass lesion with homogeneous signal intensity on every pulse sequence. The lesion showed intermediate signal intensity on the T1- and T2-weighted images. Magnetic resonance imaging of the present maxillary myxoma revealed a higher signal intensity on T1-weighted and a lower signal intensity on T2-weighted images than for previously reported myxomas of the soft tissues. This discrepancy might be related to the viscosity of the mucoid substance or the protein density of the tumor.

Regulation of colony formation of differentiated chondrocytes in soft agar by transforming growth factor-beta

Fibroblast growth factor (FGF) induces colony formation by chondrocytes in soft agar (Y. Kato et al., J. Cell. Physiol., 1987), and the present study revealed that transforming growth factor-beta(TGF-beta) does not induce the same effect. TGF-beta did, however, increase the efficiency of colony formation by chondrocytes 3- to 4-fold in the presence of a maximal dose of FGF. Furthermore, TGF-beta decreased the concentrations of FGF needed for the induction of cell growth in soft agar by 40- to 100-fold. These results suggest that TGF-beta is involved in the control of cartilage growth possibly by increasing the responsiveness of chondrocytes to FGF.

A study of the late effects of radiotherapy and operation on patients with maxillary cancer: A survey more than 10 years after initial treatment

One hundred seventy‐one maxillary carcinoma patients who survived more than 10 years after initial treatment were surveyed. Performance status was unrestricted in 35.1% of the patients, slightly restricted in 34.5%, moderately restricted in 21.1%, restricted in 7.0%, and very restricted in 2.3%. Radiation‐induced cataracts on the affected side occurred in 100% of the patients treated with radiation. Good visual acuity was maintained in only 65.8% of the patients, even on the contralateral side. Fifty‐five percent of the patients retained symmetric facial animation due to our policy of conservative therapy. Restricted mouth opening occurred in 32.2% of the patients, taking liquid diet in 21.1%, and middle ear effusion in 26.3%, which were closely linked to maxillectomy operation. This study suggests that avoiding excess radiation dosage, strict control of radiation field, adaption of two portals with 60 grades wedge pair filter, use of appropriate protectors, limiting removal at the maxillactomy, and postoperative care for trismus or tympanic effusion are necessary.

Treatment Policy for Maxillary Sinus Carcinoma

Some 908 cases of malignant tumors of the nose and paranasal sinuses treated from 1957 through 1974 were statistically analysed. The most common tumor site was the maxillary sinus (91.4%) and the most common histological figure was carcinoma (92.4%). The crude and relative survival rates for each treatment mode were calculated in January 1975. The number of cases and the 5 year relative survival rates of the main groups were as follows: I. Primary cases of malignant tumors (761 cases) 29.2% A. Carcinoma (709 cases) 29.3% B. Sarcoma (45 cases) 27.4% II. Primary cases of maxillary sinus carcinoma (561 cases) 26.1% A. Period 1957-66 (282 cases) 22.8% 1. Combination of irradiation and surgery (114 cases) 36.9% 2. Irradiation alone (168 cases) 12.7% B. Period 1967-69 (130 cases) 34.5% 1. Irradiation with 5-FU intra-arterial infusion (25 cases) 36.1% 2. Irradiation with intra-arterial infusion of other radiosensitizers (35 cases) 35.7% 3. Irradiation only without infusion (45 cases) 35.2% C. Period 1970-71, Linac X-ray irradiation (61 cases) 15.9% D. Period 1972-73, Irradiation with 5-FU infusion (80 cases), 3 year relative survival rate 39.3% The stage-grouping of maxillary sinus carcinoma based on the classification of tumor spread in the TNM system was recommended for the comparison of survival rates. The best mode of treatment in our experience is the combination of Co-60 gamma-ray irradiation and continuous intrarterial infusion of 5-FU. A curettage during irradiation is recommended. A maxillectomy should be performed only for irradiation failure cases.

Radiographic investigation ofidiopathic osteosclerosis of the jaws in Japanese dental outpatients

Panoramic radiographs of 1203 Japanese patients were examined to detect idiopathic radiopaque foci of dense bone. One hundred seventeen patients (9.7%) exhibited 134 such lesions. The majority (97%) of the opacities were found in the mandible, especially in the mandibular first premolar to second molar region (85.4%). The lesion was most prevalent in the first three decades of life.