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At least 1,045 records · Page 58Linked to original sources
PubMed2000

Associations between the eustachian tube and craniofacial skeleton.

OBJECTIVE: Growth and development of the anatomic region where the Eustachian tube (ET) is located are associated with the parameters related to other parts of the craniofacial skeleton (CFS). It has been suggested that ET dysfunction is as an important factor in pathogenesis of otitis media in childhood which is associated with its postnatal growth and development process. The purpose of this study was to evaluate associations of length of the ET with various craniofacial parameters. METHODS: On lateral cephalometric radiographs of 50 Japanese adult (25 male and 25 female), the dimension of the region where the ET is located ('length of the ET') and 22 (15 linear and seven angular) craniofacial parameters were measured by using a digitiser and computer. Correlation and regression analyses were performed between this dimension and other craniofacial parameters. RESULTS: It was found that the dimension of the region in which the ET is located ('length of the ET') was associated with many craniofacial parameters belonging to different subunits of the CFS. However, the stepwise regression analysis showed that total cranial base length, posterior upper face height and maxillary depth had determinative effects on this dimension. CONCLUSION: Development of the ET was associated with development of the cranial base and nasomaxillary complex. Therefore, it could be hypothesised that any cessation or aberration in these parts of the CFS cause corresponding imbalances in the ET, which may predispose to otitis media.

Adult↗
PubMed1996

The eustachian tube caliber and craniofacial skeleton in guinea pigs.

The temporal bone and eustachian tube (ET) keep developing up to adulthood in conjunction with facial growth, and the researchers considered that insufficient tubal function in childhood might be related to size, shape and position of the ET. In this study, we performed correlation and stepwise regression analyses between craniofacial skeletal parameters and diameter of the cartilaginous ET in 90 guinea pigs. Data showed that, not the potency of the lumen at the superior part of the cartilaginous ET, but the configuration of the cartilage surrounding the superior part of the ET, and position of the lateral lamina appeared to be significantly associated with the balance of the growth potentials between the naso-premaxillary unit, maxillo-zygomatic unit and the anterior cranial base. Therefore, we may hypothesize that the balance between these subunits of the developing craniofacial skeleton has determinative effect on tensor veli palatini muscle (TVPM).

Animals↗
PubMed1997

Scheduled activity reorganizes circadian phase of Syrian hamsters under full and skeleton photoperiods.

Circadian rhythms can be shifted or entrained by light and by arousing nonphotic stimuli. Interactions between photic and nonphotic stimuli were examined by subjecting hamsters to a daily 3 h bout of induced running under full (FPP) or skeleton (two daily light pulses; SPP) photoperiods. Activity scheduled in mid-day of a FPP induced large phase delays (260 +/- 63 min) in hamsters that ran more than 4000 rev/3 h. Split rhythms were not evident in constant dark (DD) tests. Activity scheduled in mid-subjective day of a SPP induced 180 degrees inversions of circadian phase, apparently achieved by oscillator splitting in some cases. Activity scheduled late-day and early-night induced a mix of phase delays, advances and no responses. Activity scheduled at two phase ranges late in the night had no effect, but scheduled 1 h later (beginning the last hour of darkness) induced large phase delays (238 +/- 30 min). There was no evidence of oscillator splitting during DD tests, but free-running period was significantly longer in groups that showed large phase delays. Induced running schedules have powerful effects on the phase of photic entrainment and can alter intrinsic pacemaker properties, including internal oscillator coupling and period.

Animals↗
PubMed2001

Using skeleton-based tracking to increase the reliability of optical motion capture.

Optical motion capture provides an impressive ability to replicate gestures. However, even with a highly professional system there are many instances where crucial markers are occluded or when the algorithm confuses the trajectory of one marker with that of another. This requires much editing work on the user's part before the complete animation is ready for use. In this paper, we present an approach to increasing the robustness of a motion capture system by using an anatomical human model. It includes a reasonably precise description of the skeleton's mobility and an approximated envelope. It allows us to accurately predict the 3-D location and visibility of markers, thus significantly increasing the robustness of the marker tracking and assignment, and drastically reducing--or even eliminating--the need for human intervention during the 3-D reconstruction process.

Algorithms↗
PubMed2002

Differential expressions of mPer1 and mPer2 mRNAs under a skeleton photoperiod and a complete light-dark cycle.

To investigate the molecular mechanisms in photo-entrainment of circadian rhythms, expression patterns of mouse period1 (mPer1) and mPer2 mRNAs were examined in the suprachiasmatic nucleus (SCN) and skin under a complete light-dark (LD) cycle and a corresponding skeleton photoperiod (SPP). Under the SPP, the robust daily expressions of mPer1 and mPer2 were maintained in the SCN and in the skin. A slower rise time for mPer1 mRNA expression was observed in the SPP compared with that in the LD condition both in the SCN and in the skin, although the expression pattern of mPer2 was not significantly different between the two lighting conditions. The results suggest that the expressions of mPer1 and mPer2 mRNAs are differentially regulated not only in the SCN but also in peripheral tissues. Furthermore, we propose that the persistent expression of mPer2 mRNA is required for the entrainment to the SPP.

Animals↗
PubMed1991

Central arteriovenous malformations of the maxillofacial skeleton: case report.

Central arteriovenous malformation of the maxillofacial skeleton, though rare, is a well-documented entity. Past treatments have usually included some form of surgical intervention. Surgical resection as an attempt to cure has been effective but costly, ie, in relationship to patient morbidity and hospital expenditures. A case of vascular malformation is presented in which selective angiography and embolization as a primary treatment were used rather than ablative surgery. The patient tolerated the procedures well, with complete resolution of bleeding.

Adult↗
PubMed1975

Changes of the facial skeleton in cases of neurofibromatosis.

In 12 patients with neurofibromatosis of the maxillofacial region distinct changes of the facial skeleton were found, which in localisation and extent largely conformed to the more or less wide soft tissue hyperplasias. In pronounced cases, a combined maxillo-zygomatico-temporo-mandibular hypoplasia was present radiographically. These skeletal changes hardly can be interpreted as pressure atrophy caused by the adjacent neurofibromatous tumours; more likely they are the result of complex developmental disorders. A more detailed explanation possibly will be obtained, when development and skeletal changes are controlled radiographically over a long period of time.

Adult↗
PubMed1983

Fractures of the facial skeleton in Greece. A retrospective study covering 1791 cases in 10 years.

1791 fractures of the facial skeleton covering 10 years are reviewed. There was a 3:1 male/female relationship and the majority of the cases involved the 11 to 30 years old group. Road traffic accidents by far (58%) outnumber any other cause for the injury. 56.03% of the cases arrived from the greater Athens area, which is inhabited by 40% of the population of the country. There were 1.5 fractures per patient and in the majority of the cases (78%) the mandible was involved.

Adolescent↗
PubMed2004

Effects of cessation of immunosuppression on skeleton reconstructed by vascularized bone allograft in rats.

In the present study, we investigated the effects of cessation of immunosuppression on skeleton reconstructed by vascularized allogenic bone transplantation in a rat tibio-fibula graft model. Twelve-week-old male 25 Dark Agouti rats with the major histocompatibility antigen (MHC) RT1a were used as donors and age-matched male 25 Lewis rats with MHC RT1l were used as recipients. Among them, 20 rats were randomly allocated to 8-week cyclosporine A (CsA) followed by 8-week CsA vehicle group or continuous 16-week CsA group. The remaining 5 rats received CsA for 8 weeks followed by no further treatment for next 40 weeks (long-term observation group). In the CsA followed by vehicle group as well as the continuous CsA group, the structure of the reconstructed bones was maintained, though the transplanted bones in former group were found to be partly non-vital. The CsA followed by vehicle group had higher bone mineral density of the transplanted bones and stronger strength of the reconstructed bones than the continuous CsA group. In the long-term observation group, the structure of the reconstructed bones was still maintained and the transplanted bones were almost vital. These results suggest that long-term strong immunosuppression may not be necessary for successful reconstruction of large bone defect by vascularized bone allograft.

Absorptiometry, Photon↗
PubMed1998

[Paleogenetic analysis of the skeletons from the sepulchral cave of Elzarreko Karbia (Bronze Age, Basque Country)].

Through paleogenetic studies we have characterised the sampling of a sepulchral cave named Elzarreko Karbia, in the Basque Country (France). Four people had been buried in this cave in the Ancient Bronze Age, three men, including an adolescent, and a woman, dating from 3,700 BP. In addition to a confirmation of the anatomical sex determination through amelogenin first intron amplification, we obtained a mitochondrial second hypervariable region (HVR II) sequence for each individual, and thus, we excluded maternal relationship between some of the skeletons.

Adolescent↗
PubMed2002

Activation of the bone-related Runx2/Cbfa1 promoter in mesenchymal condensations and developing chondrocytes of the axial skeleton.

The Runx2/Cbfa1 transcription factor regulates a program of gene expression necessary for skeletal development. To understand signals mediating skeletal formation, we examined the in vivo spatio-temporal activity of the Runx2 P1 promoter which controls expression of the bone-related Type II isoform. Transgenic mice carrying 3 kb of Runx2 promoter fused to the lacZ gene exhibit localized promoter activity in early mesenchymal condensations shortly after the embryonic turning event. Expression in developing mesenchyme continues throughout chondrogenesis and is restricted to the axial skeleton. Our data support a function for Runx2 in establishment of the prechondrocytic skeletal primordium.

Animals↗
PubMed1992

Influence of asymmetric occlusal relationships and decreased maxillary width on the growth of the facial skeleton in the guinea pig.

The purpose of this study was to evaluate the effect of muscle function and occlusal form on mandibular growth in guinea pigs. We hypothesized that restriction of maxillary width and asymmetric function of the mandible would lead to mandibular asymmetry. The hard palate of 12 animals was exposed at the age of ten days, and cyanocrylate was used to close the midpalatal suture in order to restrict transverse maxillary growth. The right incisors and right molars were ground obliquely at the time of surgery and every two weeks thereafter until the animals were sacrificed 4, 8 and 12 weeks later (four animals in each time group). Six age-matched animals served as controls. Dorsoversal x-rays were taken at sacrifice, followed by the removal of small biopsies from six different sites of the maxillomandibular skeleton for biochemical studies, which will be reported separately. Relative to controls, the treated animals exhibited a narrow maxilla and asymmetry in the height of the ramus and in the length of the mandible from the mental foramen to the angular process. The maximum width between the angular processes of the mandible was extremely narrow, as was the condylar neck especially on the right side. It was concluded that abnormal masticatory muscle function caused by occlusal deviation led to a narrowing and a slight asymmetry of the mandible in the growing guinea pig.

Aging↗
PubMed1999

Morphological character of the shoulder and leg skeleton in Przewalski's horse (Equus przewalskii).

The skeletal feature was observed in Przewalski's horse (Equus przewalskii) and the domestic horse (E. caballus). As results of the observations, remarkable differences were found in the scapula. The caudal border of the scapula in Przewalski's horse is curved in the caudal direction more than that of the domestic horse. Moreover, in the domestic horse, the sharp caudal border is formed by the shift of the outer muscular line (Linea muscularis) to the border. In Przewalski's horse, however, the caudal border is rounded because the outer muscular line does not shift to the border but lies beside it. We suggest that the morphological difference observed between the scapulae of these horses may lead to changes in the shoulder movement with the various attachments of the long head of the triceps muscle (Caput longum musculi tricipitis). The skeletal measurement and the measurement ratio show that the leg skeleton of Przewalski's horse is shorter and thicker than that of the domestic horse. These results show that the center of gravity of Przewalski's horse is low in position and that it has a short stride.

Animals↗
PubMed1996

Cell surface organization by the membrane skeleton.

Single-particle tracking and laser tweezers have facilitated the observation of the mechanics of molecular interactions in the plasma membrane of living cells at the level of single (or a few) molecules at nanometer/piconewton precision. These techniques have recently revealed that the membrane skeleton provides both confining and binding effects on the movement of membrane proteins, and that it can play a pivotal role in the molecular organization of the plasma membrane, especially in the formation of special membrane domains.

Biomechanical Phenomena↗
PubMed1998

Genetic control of cell differentiation in the skeleton.

The mechanisms of cell differentiation in the skeleton are just beginning to be unraveled. In the past year classical gene expression studies, genetic manipulation in mice and human genetic approaches have led to the identification of Osf2/Cbfa1 as a major regulator of osteoblast differentiation. Important progress was also made in the understanding of the control of osteoclast differentiation through the identification of osteoprotegerin and its ligand. These studies, as well as others of chondrocyte differentiation, provide a better understanding of skeletogenesis.

Animals↗
PubMed2000

Novel alpha-glucosidase inhibitors with a tetrachlorophthalimide skeleton.

Novel alpha-glucosidase inhibitors with a tetrachlorophthalimide skeleton were prepared and their structure-activity relationships were analyzed. Among them, N-phenyl-4,5,6,7-tetrachlorophthalimide (CPOP: 2) and N-(4-phenylbutyl)-4,5,6,7-tetrachlorophthalimide (CP4P: 6) showed very potent inhibitory activity, being more potent than 1-deoxynojirimycin (dNM: 1). Mechanistic studies revealed that CPOP (2) and CP4P (6) inhibit alpha-glucosidase non-competitively and competitively, respectively.

1-Deoxynojirimycin↗
PubMed2001

Specific inhibitor of puromycin-sensitive aminopeptidase with a homophthalimide skeleton: identification of the target molecule and a structure-activity relationship study.

2-(2,6-Diethylphenyl)-1,2,3,4-tetrahydroisoquinoline-1,3-dione (2: PIQ-22) was found to be a potent and specific inhibitor of puromycin-sensitive aminopeptidase (PSA). Lineweaver-Burk plot analysis showed that PSA is inhibited by PIQ-22 in a non-competitive manner. Structure -activity relationship studies indicated that tautomerism of the imidobenzoylketone group in the cyclic imide moiety of the PIQ-22 skeleton is important for the inhibitory activity.

Aminopeptidases↗