Three concurrent variations of the aberrant right subclavian artery, the non-recurrent laryngeal nerve and the right thoracic duct.

We herein report a case showing three anatomical variations including the aberrant right subclavian artery (ARSA), the non-recurrent laryngeal nerve (NRLN) and the right thoracic duct in a 59-year-old male cadaver. The right subclavian artery (RSA) arose from the descending aorta next to the left subclavian artery and coursed in between the oesophagus and the thoracic vertebrae. The recurrent laryngeal nerve did not coil around the RSA but directly entered the larynx. Lastly the thoracic duct terminated into the right brachiocephalic vein. This study makes an embryological assumption that the abnormal development of the RSA had happened first and subsequently caused NRLN and the thoracic duct drainage variation. As to our knowledge, only two reports have been made previously concerning such concurrent variations. Therefore, this case report alerts anatomists and clinicians to the possibility of simultaneous occurrence of ARSA, NRLN and the right thoracic duct.

CCR5-CCL Axis in PDL during Orthodontic Biophysical Force Application.

Tooth movement by application of orthodontic biophysical force primarily reflects the role of soluble molecules released from the periodontal ligament (PDL). Thus far, many factors have been reported to be involved in orthodontic tooth movement (OTM), but key molecules that orchestrate responses of periodontal tissues to biophysical force are still enigmatic. In this in vivo study, in which the upper first molars in rats were moved, differential display-polymerase chain reaction revealed that CC chemokine receptor 5 (CCR5) level was differentially increased during OTM. Strong immunoreactivity for CCR5 was found in the PDL undergoing force application. Moreover, the in vitro compression or tension force application to primary cultured human PDL cells increased the expression of CCR5 and CCR5 ligands. In vitro tension force on human PDL cells did not induce RANKL, an osteoclastogenesis-inducing factor, but did induce the upregulation of IL12, an osteoclast inhibitory factor, and osteoblast differentiation factors, including Runx2, which was attenuated under tension by CCR5 gene silencing whereas augmented with CCR5 ligands. In contrast, in vitro compression force did not induce the expression of osteoprotegerin, a decoy receptor for RANKL and Runx2, but did induce the upregulation of RANKL, which was attenuated under compression by CCR5 gene silencing. These results suggest that the CCR5-CCR5 ligands axis in PDL cells may play a crucial role in the remodeling of periodontal tissues and can be a therapeutic target for achieving efficient OTM.

Upregulation of relaxin receptors in the PDL by biophysical force.

OBJECTIVES: We have previously reported that relaxin (Rln) expression from the ovary is upregulated by orthodontic tooth movement. This study was performed to test the hypothesis that Rln family peptides (Rxfps), the G-protein-coupled Rln receptor, is induced in periodontal ligament (PDL) cells to modulate the molecules involved in periodontal tissue remodeling while applying biophysical force. MATERIALS AND METHODS: Rats were implanted with orthodontic appliances to investigate changes to Rxfps in vivo. An in vitro biophysical force analysis was performed to measure the level of Rxfp 1 messenger RNA (mRNA) in primary human PDL cells. RESULTS: The levels of Rxfp 2 transcription and translation increased in a time-dependent manner during tooth movement. Rxfp 2 was localized in the PDL by immunofluorescence. In vitro analyses revealed that the level of Rxfp 1 mRNA in PDL cells increased significantly with both compression and tension force. The levels of matrix metalloproteinase (MMP)-1, MMP-2, interleukin-6, and vascular endothelial growth factor mRNA, which are important for periodontal tissue remodeling, also changed under force application and Rln treatment. CONCLUSIONS: PDL cells responded to Rln to modulate effector molecules for periodontal tissue remodeling by upregulating Rxfps expression under a biophysical force. CLINICAL RELEVANCE: Rln and Rxfps may serve as a PDL turnover molecule complex to control orthodontic tooth movement.

Osteoprotegerin expressed by osteoclasts: an autoregulator of osteoclastogenesis.

Osteoprotegerin (OPG) is secreted by stromal and osteoblastic lineage cells and inhibits osteoclastogenesis by preventing the interaction of receptor activator of nuclear factor-κB ligand (RANKL) with receptor activator of nuclear factor-κB (RANK). In this study, the expression of OPG in osteoclasts themselves and its biological functions during osteoclastogenesis were investigated for the first time. OPG expression in vivo in the developing rat maxilla was examined by immunofluorescence analysis. OPG expression in osteoclasts during in vitro osteoclastogenesis was determined by reverse-transcription polymerase chain-reaction (RT-PCR), Western blot, and immunofluorescence staining. We determined the function of OPG produced by osteoclasts during osteoclastogenesis by silencing the OPG gene. The effects of OPG on bone-resorbing activity and apoptosis of mature osteoclasts were examined by the assay of resorptive pit formation on calcium-phosphate-coated plate and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining, respectively. In the immunofluorescence findings, strong immunoreactivities were unexpectedly seen in multinucleated tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts around the growing and erupting tooth germs in the rat alveolar bone. In vitro, OPG expression was significantly increased during the differentiation of osteoclasts from mouse bone-marrow-derived cells treated with a combination of macrophage colony-stimulating factor (M-CSF) and RANKL. Interestingly, it was found that OPG small interfering (si)RNA treatment during osteoclastogenesis enhanced the sizes of osteoclasts, but attenuated their bone-resorbing activity. Also, the increased chromosomal DNA fragmentation and caspase-3 activity in the late phase of osteoclastogenesis were found to be decreased by treatment with OPG siRNA. Furthermore, effects of OPG siRNA treatment on osteoclastogenesis and bone-resorbing activity were recovered by the treatment of exogenous OPG. These results suggest that OPG, expressed by the osteoclasts themselves, may play an auto-regulatory role in the late phase of osteoclastogenesis through the induction of apoptosis.

PrPc is temporospatially expressed in molar development of rats.

Odontogenesis, tooth development, is derived from two tissue components: ectoderm and neural crest-derived mesenchyme. Cyto-differentiation of odontogenic cells during development involves time-dependent and sequential regulation of genetic programs. This study was conducted to detect molecules implicated in cyto-differentiation of developing molar germs of rats. Differential display-PCR revealed that PrP(c) was differentially expressed between cap/early bell-staged germs (maxillary 3rd molar germs) and root formation-staged germs (maxillary 2nd molar germs) at postnatal day 9. Both levels of PrP(c) mRNA and protein expression were higher in the root formation stage than the cap/early bell stage and increased in a time-dependent manner. Immunofluorescence revealed for the first time that PrP(c) was not localized in the enamel organ, but localized in dental follicular cells for the development of the periodontal ligament and cementum as well as odontoblasts, both of which are of neural crest origin. These results suggest that the physiological functions of the PrP(c) in tooth development may be implicated in the differentiation of neural crest-derived mesenchyme including the periodontal tissues for root formation rather than epithelial tissue.

A false presence of bifid mandibular canals in panoramic radiographs.

OBJECTIVES: This study was performed in order to verify bifid mandibular canals revealed from panoramic radiographic results. METHODS: 1000 panoramic radiographs from dental patients and the panorama, cone beam CT (CBCT) and micro-CT from 40 dry mandibles were examined for bifid mandibular canals. The results were confirmed by a stereoscopic and histological examination of the cross-sectioned mandibles. RESULTS: The prevalence of bifid canals detected from the panoramic radiographs was 0.038. The panoramic radiographs from one dry mandible showed two separate radiolucent mandibular canal-like structures delineated by radio-opaque lines. However, a stereoscopic and histological examination of a cross-section of the mandible showed that only one canal was a true canal containing neurovascular bundles: the other was false, reflecting merely a bony trabecular pattern. CONCLUSIONS: The presence of bifid mandibular canals determined by panoramic radiography should be judged with great caution in relation to dental surgery.

Differential expression of cxcl-14 during eruptive movement of rat molar germs.

Tooth eruption at the early postnatal period is strictly controlled by the molecules secreted mainly from follicular tissues, which recruit monocytes for osteoclast formation. In this study, it was hypothesized that different molecules can be expressed according to the stages of tooth eruption. Rat molar germs together with follicles were extracted and DD-PCR was performed from the root formation stage 2nd molars germs (after eruptive movement) and cap stage 3rd molar germs (before movement) at postnatal day 9. Cxcl-14, a potent chemoattractant, was detected as one of the differentially expressed molecules from DD-PCR. Its expression increased significantly at the root formation stage, compared with the cap or crown formation stage at both transcription and translation levels. The expression patterns of cxcl-14 were consistent with those of MCP-1 and CSF-1, and opposite to OPG. Immunofluorescence showed that cxcl-14 was localized in the dental follicular tissues only at the root formation stage overlaying the proximo-occlusal region of the molar germs. Many osteoclasts appeared on the surface of the alveolar bone which overlayed the occlusal region of the root formation stage 2nd molar germs and underwent resorption. Cxcl-14 expression was reduced considerably at both the translation and transcription levels by an alendronate treatment. These results suggest that cxcl-14 may be implicated in the formation of the eruptive pathway of tooth germs via osteoclastogenesis.

Electrical and optical characterization of undoped BaTiO(3) in the quenched state.

On undoped polycrystalline BaTiO(3-delta) (99.9% nominal purity), that had been equilibrated and quenched at 1000 degrees C under different oxygen activities in the range of -19.4 < or = log a(O(2)) < 0.1, were measured optical reflectance spectra at 298 K and ac conductivity at 473, 523 and 573 K, respectively. It was observed that all specimens quenched at log a(O(2)) > -17 are electrically insulating and white in color, once powdered, and show optical absorption only at the absorption edge at approximately 3 eV. In contrast, those quenched at log a(O(2)) < -17 are electronically conducting and dark and exhibit a significant absorption in the IR region. This demarcating oxygen activity for the conductivity transition is ca. 13 orders of magnitude lower than that for the n-to-p type transition (delta = 0) in the equilibrium state, contrary to expectation. It is, thus, suggested that contrary to the textbook knowledge, the hole traps responsible for the conductivity transition in undoped BaTiO(3) may be variable-valent acceptor defects like Mn(Ti). The strong IR absorption in the semiconducting state is ascribed to small-polaron (Ti'(Ti)) hopping processes.

Hole-trapping effect on thermoelectric power of mixed ionic electronic conductor BaTiO3.

The effect of hole-trapping on the thermopower of a mixed ionic electronic conductor, e.g., BaTiO3, is analyzed in terms of irreversible thermodynamics by taking trapped holes as a fourth kind of electronic charge carrier in addition to free electrons, free holes and mobile oxide ions. It is found that the effect manifests itself in two ways: thermostatically in the ionic thermopower via the thermodynamic factor and dynamically in the electronic thermopower via the electrical conductivity contribution of the trapped holes. The thermopowers of both 99.995% pure, undoped and 1.8 m/o Al-doped BaTiO3, that were measured against oxygen activity in the range of -18 < log aO2 < or = 0 at elevated temperatures of 800 degrees to 1100 degrees C [H.-I. Yoo and C. R. Song, J. Electroceram., 2001, 6, 61, ref. 6], are reanalyzed by taking into account the hole-trapping for the doped case. It is found that while the reduced heats-of-transport of free electrons and holes are, respectively, close to their thermal energy k(B)T (k(B) being the Boltzmann constant), that of trapped holes is close to their migration energy that is essentially the same as the trapping energy onto the acceptors doped, 1.04 eV.

Psychiatric morbidity of second and third grade primary school children in Korea.

This study was undertaken to identify psychiatric morbidity among Korean second and third elementary school children using an objective diagnostic interview tool. Data from 5,118 (2,723 boys, 2,395 girls; mean age = 8.41 years (SD = 0.66)) second and third grade schoolchildren were drawn from 28 elementary schools. After initial screening assessments using the 28-item Child Problem-Behavior Screening Test for parents, 672 primary caregivers were subjected to secondary screening using the Korean version of the CBCL. Two hundred and seventy-one high-risk children selected according to the K-CBCL results, 138 (50.9%) children and their primary caregivers were interviewed using the Korean version of K-SADS-PL for objective DSM-IV psychiatric diagnoses. Sixty-four (46.4%) of the hundred and thirty eight children were determined to have at least one psychiatric disorder. More boys were diagnosed as psychiatric patients than girls (46 males, 18 females; OR = 2.21). The most frequently diagnosed disorder was ADHD (46/64; 71.9%), followed by tic disorder, anxiety disorders, mental retardation, oppositional defiant disorder, and separation anxiety disorder. Two or more comorbid psychiatric disorders were found in 22 (34.4%) of the 64 patients. The computed crude percentage of psychiatric patients in this study was 4.12%, which is similar to previously published data.

Effect of hole-trapping on mass/charge transport properties in acceptor-doped BaTiO3.

The equilibrium conductivity and chemical diffusivity of Al-doped, single-crystalline BaTiO3 [C. R. Song and H. I. Yoo, J. Am. Ceram. Soc., 2000, 83, 773] have been re-analyzed by taking account of possible hole-trapping by acceptor-dopants (Al) with reference to the data on undoped BaTiO3 [C. R. Song and H. I. Yoo, Phys. Rev. B, 2000, 61, 3975]. The trapping effect is accounted for by the effective mobility of free holes involving the weighted mobility of trapped holes and by the modified thermodynamic factor due to the shift of the stoichiometric composition of the acceptor-doped system. The equilibrium constant of the trapping reaction Al(Ti)x = Al(Ti)' + h* is evaluated as Ka = 1.9 x 10(23) exp(-1.04 eV/kT) cm(-3) and the mobility of trapped holes (Al(Ti)x) as u(x) approximately = 720 exp(-1.04 eV/kT) cm2 V(-1) s(-1) as the upper bound while those of free electrons and holes as un = 0.044 + 0.010 cm2 V(-1) s(-1) and up approximately = 0.024 +/- 0.007 cm2 V(-1) s(-1), respectively, in the temperature range of 800 degrees C to 1100 degres C. The effect of hole-trapping on DC conductivity, chemical diffusivity and oxygen nonstoichiometry is exhaustively analyzed and further experiments are proposed that allow one to determine the trapping energy of acceptor impurities.