Identification of a receptor type guanylyl cyclase in the antennal lobe and antennal sensory neurons of the silkmoth, Bombyx mori.

Sensory neuron-specific guanylyl cyclases (GC), which were recently identified in rodents and nematodes, are thought to be a new family of odorant/pheromone receptors. In the antennae of the male silkmoth Bombyx mori, receptor type GC are supposed to mediate signaling of pheromone. Structure of receptor type GC expressed in insect sensory neurons has remained unidentified. Here we report the isolation of cDNA of the receptor type GC, designated BmGC-I, from the male silkmoth antennae. The deduced amino acid sequence indicates that BmGC-I appears to consist of four domains: an extracellular, single transmembrane, kinase-like and a guanylyl cyclase domain. BmGC-I is most closely related to the mammalian natriuretic peptide hormone receptor A (GC-A) and retains all the cysteine residues that are conserved within the extracellular domain of the mammalian GC-As. Transcripts of the BmGC-I gene were detected in various tissues; the flight muscles, midgut, legs, ganglion, Malpighian tubules, testis and the head. Immunohistochemical study revealed that the BmGC-I protein localizes in the antennal-lobe glomerulus and in the soma and axon of sensory neurons. We thus suggest that BmGC-I plays functional roles in the odorant information processing and the modulation of excitability in the antennal sensory neurons.

Fourteen-year survival in a case of ventricular septal perforation after myocardial infarction.

We treated a case of ventricular septal perforation (VSP) who survived for 14 years after myocardial infarction. Nine years after the onset of myocardial infarction, an apparent cardiac murmur was discovered by chance, and following further examination, the patient was diagnosed as having VSP. The patient is still in the NYHA functional class I, and requiring no surgical treatment. In general, the prognosis of myocardial infarction complicated with VSP is so poor that there have only been 14 reported cases of long survival without surgical treatment. Among these patients, only 2 survived for more than 10 years. The present case is extremely rare, and evidently is the longest living survivor with this condition yet reported.

Lipid peroxidation induced by adriamycin in linolenic acid-loaded cultured hepatocytes.

Addition of more than 10 microM of adriamycin to cultured rat hepatocytes loaded with alpha-linolenic acid (linolenic acid-loaded hepatocytes) caused marked lipid peroxidation as measured by an accumulation of malondialdehyde during a 9 hr incubation. After addition of 50 microM of adriamycin to linolenic acid-loaded hepatocytes, malondialdehyde accumulation significantly increased at 3 hr, followed by cellular reduced glutathione decrease and lactate dehydrogenase leakage after 6 hr. Inhibition of adriamycin-induced lipid peroxidation by addition of N,N'-diphenyl-p-phenylenediamine or alpha-tocopherol, both lipid radical scavengers, or deferoxamine, which is a Fe ion chelator, prevented both glutathione decrease and lactate dehydrogenase leakage, indicating that lipid peroxidation caused cellular damage to linolenic acid-loaded hepatocytes exposed to adriamycin. The effect of SKF 525-A, which is a cytochrome P450 inhibitor, on adriamycin-induced lipid peroxidation and on 7-ethoxycoumarin O-deethylase activity was determined by 6 hr incubation of linolenic acid-loaded cells. Addition of SKF 525-A suppressed adriamycin-induced lipid peroxidation comparably with its 7-ethoxy-coumarin 0-deethylase inhibitory activity. These results suggest that cytochrome P450 contributes to the one-electron bioreduction of adriamycin into its semiquinone radical in rat hepatocytes.

Difference in the mechanism of balancing-side disclusion between 1st and 2nd molars.

This study investigates the cusp angle and movement variables related to balancing-side disclusion and compares the characteristics between the 1st and 2nd molar regions. Fifty-six normal young adults were divided into two groups according to balancing-side contact: a disclusion group consisting of 40 subjects (80 excursions), and a non-disclusion group consisting of 16 subjects (20 excursions). Lateral excursions were measured in six-degrees of freedom, and the inclinations of the frontal paths were calculated on the working-side canine, balancing-side 1st and 2nd molars and balancing-side condylar point. The cusp angle was measured using a three-dimensional digitizer. While there were no differences between disclusion and non-disclusion groups in the inclination of the balancing-side condylar path, significant differences were found in the cusp angle and the inclination of the working-side canine path. In the non-disclusion group, the cusp angle of the 2nd molar was markedly greater than that of the 1st molar. It was concluded that the inclination of the anterior guidance and the cusp angle of related teeth have a great effect on the occurrence of balancing-side disclusion and that the mechanism of high frequent balancing-side contacts at the 2nd molar was characterized by its greater cusp angle compared to the 1st molar.

Effect of altered canine guidance on condylar movement during laterotrusion.

PURPOSE: The purpose of this study was to investigate the effect of an altered inclination of the canine guidance on the pattern of the condylar movements during laterotrusion. MATERIALS AND METHODS: The inclination of the canine guidance was steepened approximately 10 degrees by attaching a metal overlay to the lingual surface of the maxillary working-side canine. The laterotrusive movements of 20 young adults were measured using a three-dimensional mandibular movement analyzing system before and after alteration of the canine guidance. The difference between anterior, lateral, and inferior components of the working- and nonworking-side condylar movements, the Bennett angle, and the sagittal inclination of the nonworking-side condylar path before and after steepening of the canine guidance was evaluated by a paired t test. RESULTS: After the canine guidance was steepened, the working-side condyle moved even more anteriorly and inferiorly. In contrast, little change was found in the direction and the amount of the nonworking-side condylar movement. CONCLUSION: The results of this study suggest that there is a relationship between the steepness of canine guidance and the pattern of the working-side condylar movement. but not between the steepness of the canine guidance and the pattern of the nonworking-side condylar movement.

An immunoelectron microscopic localization of noncollagenous bone proteins (osteocalcin and osteopontin) at the bone-titanium interface of rat tibiae.

This study was designed to investigate by postembedding immunogold method the localization and distribution of osteocalcin (Ocl) and osteopontin (Opn) at the bone-titanium interface in rat tibiae 14 and 28 days postimplantation to determine which bone proteins are present at this interface. Both proteins were widely distributed on the newly formed bone and accumulated predominantly in the region of bone close to the titanium, in electron-dense patches in the bone, and at the osteocytic lacunae. Collagenous osteoid showed little or no labeling for either Ocl or Opn. An amorphous zone (20-50 nm) was interposed between the titanium and interfacial slender cells, osteoid, or bone, and was labeled strongly for Ocl but only weakly for Opn. Furthermore, a second electron-dense layer, the lamina limitans, which faces the titanium, was labeled strongly for Opn but weakly for Ocl. Ocl as a marker protein of osteoblasts was sometimes found in the granules and vesicles of the interfacial cells and extracellularly in their intercellular spaces, close to the titanium. However, Opn was not detected in any granules. This is the first report to show that the amorphous zone contains large amounts of Ocl and small amounts of Opn, and that bone contacts titanium through this Ocl-rich amorphous zone. Furthermore, it is suggested that the interfacial cells seem to be osteoblasts, and that Ocl in the amorphous zone is produced and secreted by these cells and functions with Opn as a regulator of the mineralization front close to the titanium, and as a mediator of cell-matrix and matrix-matrix/mineral adhesion along the titanium.

Uncontrolled diabetes hinders bone formation around titanium implants in rat tibiae. A light and fluorescence microscopy, and image processing study.

This study examined the influence of diabetes mellitus on bone formation around cylindrical titanium (Ti) implants (1.0 mm in diameter and 1.5 mm in length) inserted transcortically and extending into the medullary canal of rat tibiae using light and fluorescence microscopies and image processing. Forty-eight male Wistar King A rats (age 5 weeks) were used in this experiment. Streptozotocin was injected intraperitoneally to induce diabetes and the serum glucose concentration was checked to ensure the induction of diabetes prior to implant placement and at the time of sacrifice. The animals were sacrificed 7, 28, 56, or 84 days after placement. Toluidine blue-stained undecalcified sections were prepared for histological observation and image analysis. The Ti implants in the control group became increasingly encapsulated with a bone layer. The implants in the diabetes-induced (DI) group were also surrounded with a thin bone layer. Abundant adipocytes were observed in the DI group as compared with the control group. Quantitative evaluation indicated that the control group showed a significantly higher percent of bone contact, and thickness of surrounding bone and area than the DI group. Consequently, the present study suggests that uncontrolled diabetes would hinder bone formation around Ti implants in rats.

An immunocytochemical study for lysosomal cathepsins B and D related to the intracellular degradation of titanium at the bone-titanium interface.

The morphological relationship between titanium and lysosomal proteinases, cathepsins B and D, at the bone-titanium interface using titanium-coated plastic implants placed for 28 days in the tibiae of 6-week-old rats was immunocytochemically investigated by the colloidal immunogold-silver method. Under light microscopy the titanium layer appeared to make direct contact with the bone and one or a few layers of slender cells were interposed between the bone and titanium. Ultrastructurally, the titanium came in contact with the bone or the slender cell layer through a 20 to 40 nm thin amorphous zone. The slender cells at the bone-titanium interface consisted of two types; one was an osteoblast type with glycogen granules which was found along the newly-formed bone facing titanium layer. The other was a fibroblast type which came in contact with the titanium layer and occasionally endocytosed the detached titanium fragments. In addition, some of the slender cells also showed degenerative changes. Immunocytochemically, cathepsins B and/or D were sometimes colocalized in some phagolysosomes with titanium fragments. These findings suggested that the fibroblast types at the bone-titanium interface may act as scavengers to remove both cell debris and titanium by means of some endocytotic ability, and lysosomal cathepsins also developed in response to the endocytosed titanium. The osteoblast type also appears to show a high degree of osteogenic activity around the titanium-coated plastic implants.

Correlation between inclination of occlusal plane and masticatory movement.

OBJECTIVES: The purpose of this study was to investigate the relationship between the inclination of the occlusal plane and masticatory movement. METHODS: Masticatory movements of 41 young adults were measured using the three-dimensional Mandibular Movement Analyzing System. The inclination of the occlusal plane was measured in the sagittal plane using a three-dimensional digitizer. RESULTS: In the sagittal plane, the masticatory closing path and the occlusal plane were consistent in maintaining a perpendicular relation with each other regardless of the inter-individual variation of the inclination of the occlusal plane. Subjects with an anteriorly inclined occlusal plane showed a vertical closing path, and subjects with a posteriorly inclined occlusal plane showed a flat closing path in the frontal plane. These characteristics were explained by the variation of the timing on the balancing-side condylar return correlated with the inclination of the occlusal plane. CONCLUSIONS: There is a significant correlation between the inclination of the occlusal plane and the direction of the closing path during mastication.

Long-term evaluation of bone-titanium interface in rat tibiae using light microscopy, transmission electron microscopy, and image processing.

We conducted a 2-year histologic and histometric evaluation of the tibial bone-titanium (Ti) implant interface in male rats. Thirty male 6-week-old rats were used in this study. They were divided into two groups: 15 for day 28 and 15 for day 730. Microscopic observation at day 28 revealed that the newly formed bone around the implant almost surrounded the implant, but fibroblastlike cells were interposed in some histologic sections. At day 730, in contrast, such cells were rarely seen, and the bone around the implant presented a lamellar structure. Transmission electron microscopic observation at day 28 disclosed mature or poorly mineralized bone near the implant; however, an electron-dense amorphous zone about 50 nm in thickness was interposed between the bone and Ti. In places slender cells were interposed between the bone and Ti. The amorphous zone was also observed at the cell-Ti interface. At day 730, a poorly mineralized layer remained in some areas between the mature bone and the titanium, and the interposed amorphous zone was still observed. Occasionally, a 200-nm-thick layer, thought to be cell remnant, was seen. As calculated in an image-processing, system analysis, the percent bone contact and the thickness and area of the surrounding bone for the Ti implant at day 28 were 43.6%, 30.4 microns, and 0.10 mm2, respectively, and those at day 730 were 89.9%, 53.5 microns, and 0.19 mm2, respectively. In summary, although the passage of time may affect bone maturity, interfacial cells remain at the bone-Ti interface as a uniform layer together with unmineralized bone.

Histological comparison of early wound healing following dense hydroxyapatite granule grafting and barrier placement in surgically-created bone defects neighboring implants.

The purpose of this study was to examine early wound healing following grafting of dense hydroxyapatite granules (HA granules) and barrier placement in surgically-created bone defects surrounding implants. Eight healthy adult dogs with an average weight of 15 kg were used in this study. Thirty-two bone defects measuring 4 mm x 4 mm were removed with a surgical bur to form continuous bucco-lingual bone defects and 32 implants (16 titanium [Ti]) and 16 hydroxyapatite-coated [HA]) were then placed into the defects. Four implant groups were created: 1) grafting HA; 2) covering with an expanded polytetrafluoroethylene (ePTFE) membrane; 3) grafting HA and covering with ePTFE membrane; and 4) control (no treatment). Animals were sacrificed 28 days after surgery. Histological sections revealed large amounts of newly-formed bone in all bone defects surrounding the implants treated with ePTFE membranes alone. Fibrous encapsulation of HA granules was observed in the defects of the HA granules grafting group. In the group with grafting of HA granules and covering with ePTFE membranes, small amounts of bone tissue were observed among HA granules, but most HA granules were surrounded with fibrous tissue. Bone defects were completely filled with connective tissue in the control group. There were no differences in the histological findings between Ti and HA-coated implants in all cases. Histomorphometric data disclosed that the presence of HA granules in the bone defects significantly arrested bone formation. Our study suggests that the grafting of dense HA into bone defects surrounding implants will result in fibrous healing during the early healing stage.

Characteristics of masticatory movement in relation to inclination of occlusal plane.

The relationship between masticatory movement and the inclination of the occlusal plane in sagittal plane was analysed in 41 young adults. It was found that the occlusal plane and the masticatory closing path were consistent in maintaining an almost perpendicular relationship with each other, regardless of the variation in inclination of the occlusal plane. This finding can be explained by the observation that the timing of the balancing-side condylar translation during closure correlated with the inclination of the occlusal plane. The inclination of the occlusal plane also influenced the masticatory closing pattern in the sagittal plane. Anterior convex closure patterns dominated when the occlusal plane inclined in the anterior direction. In contrast, the majority of posterior convex closure patterns were induced by the posteriorly inclined occlusal plane. The appearance of these types seems to reflect a harmonious relationship between the inclination of the occlusal plane, tooth guidance, and other central and peripheral control. The correlation between the inclination of the occlusal plane and masticatory closing movement could serve as the functional background for the significance of the occlusal plane.

The influence of anterior guidance and condylar guidance on mandibular protrusive movement.

This study reveals the influence of the incisal and condylar guidance on mandibular protrusive movement. The protrusive movements were measured on 54 young adults (27 females, 27 males) using a three-dimensional mandibular movement analysing system. The inclinations of the sagittal paths on the incisor, canine, 1st molar, 2nd molar and condylar points were calculated, and multiple regression analysis was performed to evaluate the influence of the incisal and condylar paths on the path of each tooth quantitatively. The influence of the incisal path on any tooth path was consistently greater than that of the condylar path. The condylar path had a greater influence on the paths of posterior teeth than on the paths of anterior teeth, especially in the female subjects. The influence of the condylar path on the molar paths was twice as great in the female than that in the male subjects. It was concluded that the influence of the incisal and condylar guidance on the protrusive movement path varies according to the kind of tooth and the gender of the subject. These guiding system characteristics were confirmed by morphological analysis.

Effect of occlusal splint on masticatory movement in healthy individuals.

To investigate the effects of wearing an occlusal splint on masticatory movements in healthy individuals, twelve healthy individuals were examined. A full maxillary stabilization splint made of heat-cured acrylic resin was fabricated for, and worn by, each individual for 24 hours. Masticatory movement was measured before and after the 24-hour period using a 3-D mandibular movement analyzing system. While the duration of a masticatory cycle+ did not change, the occlusal time significantly decreased after use of the splint. The lateral displacement of the opening phase to the balancing-side area also decreased after use of the splint, showing a vertical pattern of the opening path. Measurement in more healthy individuals and patients should help clarify the therapeutic mechanism of the splint in the treatment of temporomandibular disorders.

Failing hollow implants examined by light microscopy and image processing.

The purpose of this study was to evaluate the radiologic, histologic, and histometric findings of three failing hollow implants. On periapical radiographs, these implants showed vertical bone loss up to the hollow portion around the implant. Examination of the histologic sections disclosed that the hollow portions of all the implants were almost filled with bone tissue, although slight bone resorption and presence of granulation tissue infiltrated with inflammatory cells was observed coronal to the hollow portion. Histometric analysis disclosed that the average percent bone contact was 93.1% in case 1, 90.9% in case 2, and 84.3% in case 3 and the average percent bone filling was 42.1%, 50.5%, and 33.8%, respectively. Consequently, there seems to be some potential for successful treatment of these implants because the destructive changes were limited to the coronal aspects of the implant.

Abscess formation around a hydroxyapatite-coated implant placed into the extraction socket with autogenous bone graft. A histological study using light microscopy, image processing, and confocal laser scanning microscopy.

The purpose of this study was to evaluate the radiologic, histologic, and histometric findings for a retrieved hydroxyapatite (HA)-coated implant which had been placed into a fresh extraction socket with autogenous bone graft 3 months previously. A periapical radiography disclosed a vertical bone loss around the implant cervix. Examination of histologic section disclosed that granulation tissue including bone chips around the cervix, and newly-formed bone tissue around the grafted bone tissue on the HA coated surface. In the confocal laser scanning microscopic findings toluidine blue-negative bone tissue showed autofluorescence. Histometric analysis indicated that the average percent bone contact was 29.2% (ranged 26.4% to 34.1%). Suspected reasons for failure were an early exposure of the barrier membrane, its early removal, the implant placement into an infected site, inadequate antibiotic premedication, and/or poor control of infections around teeth prior to implant surgery and around implants before and after placement of barrier membrane.

The effects of diabetes on the interface between hydroxyapatite implants and bone in rat tibia.

We examined the influence of diabetes on the implant-bone interface of hydroxyapatite (HA) implants inserted transcortically and extending into the medullary canal of rat tibiae, and quantitatively assessed the differences in bone reaction using an image processing system. Forty male Wistar King A rats (aged 5 weeks) were used in this experiment; they were sacrificed 84 days after implant placement. Toluidine blue-stained undecalcified sections were prepared for histological observation and image analysis, and the labeled sections were observed by confocal laser scanning microscopy. The HA implants in the bone marrow area in the control group were completely encapsulated with a bone layer, and there were some osteoblast-like cells in the bone lacunae apposing the implant surface. The HA implants in the diabetes-induced (DI) group were partially surrounded with a thin bone layer, and there were some fibroblasts running parallel to the implant surface at areas of no bone contact. Quantitative evaluation indicated that the control group showed significantly higher bone contact rate, bone contact thickness, and bone contact area than the DI group. The DI group showed approximately 30% reduction in the percentage of bone contact and 50% reduction in the thickness and the area of surrounding bone tissue.

Study of bone formation around dense hydroxyapatite implants using light microscopy, image processing and confocal laser scanning microscopy.

The bone reaction to hydroxyapatite (HA) implants inserted transcortically and extending into the medullary canal of rat tibiae was quantitatively assessed using light microscopy, confocal laser scanning microscopy and an image processing system. Sixty-five male rats (6 weeks old) were divided into two groups, 60 for histological observation and image analysis and five for time-labelling. In the histological observation, control sections of 168 days showed a few bone trabeculae in the fatty bone marrow, and Ti implants had become gradually encapsulated with a thick bone tissue layer; however, HA implants became almost completely encapsulated with a thin bone tissue layer during the 168 day experimental period. Histometrical analysis of the percent bone contact revealed that Ti implants showed a continuous increasing curve, and HA implants showed rapid increase in the initial healing period up to 14 days, with 96% bone contact reaching a plateau at 84 days after operation. There was a significant difference in the percent of bone contact between Ti and HA implants throughout the experimental period. Confocal laser scanning microscopic observations revealed the presence of calcein at the 14th day and only slight alizarin colour layer in the bone tissue at the 28th day, both indicating bone formation. These findings suggest that the activity of bone formation was higher at the 14th day than at the 28th day. Also, the percentage of bone contact of HA is superior to titanium throughout the experimental period, and the ascending patterns of both implants are quite different to each other.

Various designs of ceramometal crown for implant restorations.

The posterior design of the implant superstructure (the ceramometal crown) was classified into four categories: a ceramometal crown with an access hole on top; a cemented ceramometal crown; a ceramometal crown retained with a lingual screw; and a telescopic ceramometal crown. Cemented ceramometal crowns and telescopic ceramometal crowns are considered simpler, more esthetic, and more resistant to fracture among the four models.