Masayoshi Sakuda

Cemento-osseous dysplasia of the jaws in 54 Japanese patients: A radiographic study

OBJECTIVE The aim of this study was to describe the radiographic patterns of cemento-osseous dysplasia. STUDY DESIGN Fifty-four patients affected with benign fibro-osseous jaw lesions that showed periapical radiopacities and/or radiolucencies in a focal or a multiplex form were studied. The clinical, radiographic, and histopathologic features of the patients with cemento-osseous dysplasia were retrospectively studied. Radiographic features of the cemento-osseous dysplasia lesions were classified according to the appearance of calcified bodies. Radiographic visibility of periodontal ligament spaces of related teeth was assessed. RESULTS Forty-nine (91 %) of the 54 patients were women. The mean age of the total group was 50.8 years, and that of the male group was 64.6 years. The cemento-osseous dysplasia lesions could be classified into 6 types radiographically. Eighteen patients had at least 2 or more types of cemento-osseous dysplasia lesions. Of 147 related teeth, 142 had periodontal ligament spaces clearly visible. Six of 9 patients who had a total of 25 teeth with active hypercementosis showed concomitant occurrence of other types of cemento-osseous dysplasia lesions. Biopsy specimens showed various amounts of bonelike and cementumlike tissues. CONCLUSIONS It is likely that cemento-osseous dysplasia consists of 3 variations of a single entity, all with the same unknown cause. In one variation, the entity originates from the periodontium; in another, it is of medullary bone origin; and in the third it results from the simultaneous involvement of both tissues.

Regeneration of periodontal primary afferents of the rat incisor following injury of the inferior alveolar nerve with special reference to neuropeptide Y-like immunoreactive primary afferents.

Regeneration of primary afferents and the expression of neuropeptide Y (NPY) in the lingual periodontal ligament of the rat incisor were examined following different types of injury (resection or crush) of the inferior alveolar nerve (IAN) combined with superior cervical ganglionectomy. In normal animals, protein gene product 9.5 (PGP 9.5)-like immunoreactivity (-LI) was localized in the middle areas of the alveolus-related part of lingual periodontal ligament; some of these nerve fibers showed terminal ramification and morphologies resembling those of the periodontal Ruffini endings, and very few thin varicose NPY-like immunoreactive (-IR) nerve fibers were detected around the blood vessels. Three days following crush injury of the IAN, the number of PGP 9.5-IR nerve fibers decreased, then increased to the normal levels around 10-15 days following injury. NPY-IR primary afferents first appeared around 5 days following crush injury, increased in number gradually, reaching a peak around 14 days, and then decreased. No NPY-IR primary afferents were detected 56 days following crush injury of the IAN. The terminal morphology of NPY-IR primary afferents observed around 10-14 days following injury was similar to that of PGP 9.5-IR nerve fibers in the normal animals, but less expanded. The changes in distribution of PGP 9.5-IR and NPY-IR nerve fibers following resection were similar to those observed following crush injury but regeneration was slightly delayed. The present results suggest that injury-evoked NPY is closely associated with the regeneration process of mechanoreceptors in the periodontal ligament following injury of the IAN.

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.

Three-Dimensional Comparison Between the Palatal Forms in Complete Unilateral Cleft Lip and Palate with and without Hotz Plate from Cheiloplasty to Palatoplasty

The palatal forms in 20 infants with a complete unilateral cleft lip, and palate (12 with a Hotz palate and 8 without, selected at random) were studied from birth until 18 months of age. Using techniques developed previously, the degree of curvature in the palate and the magnitude of migration of the maxillary segments were measured three-dimensionally. Furthermore, using a newly developed method to approximate a set of the points on the alveolar ridge to a circle in a plane, the form of the alveolar arch was evaluated. Results from the group with a Hotz plate revealed that the plate possesses four effects not seen in the group without a Hotz plate. The size of the palate was larger, and the sagittal gap between the two segments of the maxilla was smaller. These results suggest that the appliance could stimulate the growth of the segments and could prevent collapse of the maxillary arch from the force of lip closure. Third, the steepness of the segments toward the nasal cavity was smaller, possibly occurring because the appliance prevents tongue intrusion into the cleft. Fourth, the magnitude of migration of the lesser segment toward the cleft edge of the major segment was larger. This result suggests that the appliance could guide the growth of the maxillary segments to narrow the cleft width until 18 months of age.

Three-Dimensional Comparison between the Palatal Forms in Infants with Complete Unilateral Cleft Lip, Alveolus, and Palate (UCLP) with and without Hotz's Plate

A three-dimensional measuring system was developed to analyze changes in palatal forms of UCLP infants. This system quantified the change of the curved surface on a palate by automatically superimposing two wireframe models obtained from casts at different stages of growth. It also analyzed the curvature of the palatal surface. This system was used to study the palates of 20 infants with unilateral cleft lip and palate (UCLP), from the first to fourth months after birth (12 with Hotzs plate and 8 without, selected at random). Both major and lesser maxillary segments without Hotzs plate remained anterior and lateral although those with Hotzs plate moved mesially during the fourth month after birth. In addition, the degrees of curvature on the palatal surfaces with Hotzs plate were less than those without Hotzs plate.

Morphine prevents peroxynitrite-induced death of human neuroblastoma SH-SY5Y cells through a direct scavenging action

N-ethyl-2-(1-ethyl-2-hydroxy-2-nitrosohydrazino)-ethanamine (NOC12), a nitric oxide donor, 3-morpholinosydnonimine (SIN-1), a generator of peroxynitrite (ONOO-), and peroxynitrite induced cell death accompanied by DNA fragmentation in human neuroblastoma SH-SY5Y cell cultures. Morphine prevented the cell death induced by SIN-1 or peroxynitrite, but not that induced by NOC12. The protective effect of morphine was concentration-dependent (10-100 microM), but was not antagonized by naloxone. The selective ligands for opioid receptor subtypes, [D-Ala2, N-Me-Phe4, Gly-ol5]enkephalin (DAMGO, micro-opioid receptor agonist), [D-Pen2,5]enkephalin (DPDPE, delta-opioid receptor agonist) and trans-(+/-)-3,4-dichloro-N-methyl-N-(2-[1-pyrrolidinyl]-cyclohexyl)benze neacetamide (U-50488, kappa-opioid receptor agonist) even at the concentration of 100 microM did not prevent the cell death induced by SIN-1. From measurement of the absorbance spectrum of peroxynitrite, the decomposition of peroxynitrite in 0.25 M potassium phosphate buffer (pH 7.4) was very rapid and complete within seconds. However, the absorbance was very stable in the presence of morphine. In addition, morphine inhibited peroxynitrite-induced nitration of tyrosine in a concentration-dependent manner. These results indicate that morphine rapidly reacts with peroxynitrite. The present study showed that morphine prevented peroxynitrite-induced cell death through its direct scavenging action, suggesting that morphine can protect cells against damage caused by peroxynitrite.

Comparison Between Palatal Configurations in UCLP Infants with and without a Hotz Plate Until Four Years of Age

OBJECTIVE To evaluate the efficacy of presurgical orthopedic treatment three dimensionally, we previously developed a novel measuring system and described the efficacy of the treatment until 18 months of age. The aim of this study was to compare palatal configuration in complete unilateral cleft lip and palate (UCLP) infants fitted with a Hotz plate to those without it until four years of age using the same measuring system. PATIENTS Twenty complete UCLP infants were divided into two groups. A Hotz plate was used with 12 patients who first visited our clinic from January 1990 to March 1992 and was not used with an additional eight patients who first visited from April 1992 to July 1993. MAIN OUTCOME MEASURES Palatal casts taken from birth until four years of age were measured three dimensionally and were compared between the two groups. RESULTS AND CONCLUSIONS The width of the palate was larger in the group with a Hotz plate than in the group without it at four years of age. No difference was observed between the anteroposterior distance of the palate in the two groups at four years of age. Similarly, the alveolar arch form did not differ between the two groups. The degree of curvature of the palatal surface was smaller in the group with a Hotz plate than in the group without it. These data were similar to data obtained at 18 months of age.

Changes in [3H]Nitrendipine Binding and γ-Aminobutyric Acid Release in Rat Hippocampus Following Repeated Morphine Administration

Abstract: An antagonistic effect of calcium on the action of morphine was studied in rat hippocampal slices. The effect of repeated administration of morphine on γ‐aminobutyric acid (GABA) release and binding of [3H]nitrendipine, a cal‐cium antagonist, was also examined. (1) In rat brain hippocampal slices, morphine enlarged the amplitude of the field potentials evoked in pyramidal neurons, disinhibiting them through basket cells. When the calcium concentration was elevated, potentiation of the field potentials by morphine was reduced. Decrease of the calcium concentration, on the other hand, enhanced the potentiating effect of morphine. Following repeated administration of morphine, its enhancing effect on the field potentials in slices was not observed. (2) In hippocampal membrane fractions obtained from rats repeatedly treated with morphine, enhancement of [3H]nitrendipine binding was observed. (3) In hippocampal slice preparations from rats receiving morphine repeatedly, K+ (45 mM)‐stim‐ulated [3H]GABA efflux was enhanced. The above results indicate that morphine antagonizes calcium, thereby reducing the release of transmitters. Furthermore, increase in calcium channels following repeated treatment of rats with morphine may explain the mechanism underlying development of tolerance.

Gigantic dense bone island of the jaw

The clinical and radiographic features of gigantic dense bone islands of the jaw were reviewed in 21 subjects to better determine the pathogenesis of this condition. Most of the islands were asymptomatic. They showed a striking predilection for occurrence in the premolar to molar region of the mandible. The greatest dimension of gigantic dense bone islands measured on panoramic radiographs ranged from 2.5 to 7.0 cm, and they were most commonly structureless radiopaque areas. None showed bony expansion buccolingually, nor did they displace adjacent teeth or bony anatomic structures. It is concluded that gigantic dense bone island is not a benign bone neoplasm and is perhaps merely a large counterpart of smaller dense bone islands or idiopathic osteosclerosis.

Decrease in analgesic effect of nifedipine following chronic morphine administration

The analgesic effect of nifedipine, a calcium antagonist, was compared in the acetic acid-induced writhing test with control and morphine-tolerant mice. Nifedipine inhibited the writhing syndrome less effectively in mice made tolerant to morphine. The results support the notion that inhibition of the calcium influx is one of the causes of the analgesic action of morphine and that its chronic administration causes an increase of calcium entry.