Neurotransmission, Vasculogenesis, and Osteogenesis Activities are Altered in the Aging Temporomandibular Joint of the Senescence-Accelerated Prone 8 Mouse Model.

BACKGROUND: Alterations in neurotransmission, vasculogenesis, and osteogenesis pathways that may play pivotal roles in age-related changes in the temporomandibular joint (TMJ) are poorly understood. PURPOSE: This study aimed to measure the associations between gene and protein profiles in senescence-accelerated prone 8 (SAMP8) mice. STUDY DESIGN: The investigators designed and used 3 groups of 2 mouse models: 1) early aging SAMP8 at 24 weeks of age and control SAMR1 at 12 and 24 weeks (each stage n = 12). PREDICTOR/EXPOSURE/INDEPENDENT VARIABLE: The independent variable was investigated using 3 mouse models: an early aging mouse model and a control mouse model (12 and 24 weeks). MAIN OUTCOME VARIABLE(S): The primary outcome variables were CGRP, VEGF-A, CD31, LYVE-1, osteocalcin, osteopontin, type I and II collagen, and MMP-2. The secondary outcome variables were histological characteristics. COVARIATES: Not applicable. ANALYSES: The gene and protein expression profiles of neurotransmitters, vasculogenesis, and osteogenesis were identified by quantitative real-time polymerase chain reaction and dot blot analysis, respectively. The cellular localization of these events was verified by in situ hybridization and immunohistochemistry. Bivariate statistics were computed for each of the outcome variables. Statistical significance was set to a P value < .05. RESULTS: The expression of CGRP mRNA in the bony mandibular condyle (BMC) of SAMP8 mice (SAMP8, 3.3 ± 0.39 vs SAMR1, 0.001 ± 0.0001) was high at 24 weeks of age (24 weeks) (P < .001). Higher numbers of cells positive percentage for CGRP (MF, SAMP8, 28.67 ± 1.60 vs SAMR 1, 6.36 ± 1.10; CMC, 27.5 ± 2.12 vs 9.00 ± 1.21; BMC, 31.31 ± 2.81 vs 7.85 ± 1.14) and VEGF-A (MF, 34.43 ± 2.45 vs 14.01 ± 1.28; MD, 32.69 ± 1.86 vs 8.00 ± 0.91; CMC, 36.60 ± 2.05 vs 14.19 ± 1.25 BMC 36.49 vs 12.59 ± 1.41) antibodies were found in the 24 weeks TMJ (P < .01). CONCLUSIONS AND RELEVANCE: The neurotransmitter, vasculogenesis, and osteogenesis pathways are associated with TMJ aging in the SAMP8 mouse model. In the future, the SAMP8 mouse model may prove to be a robust model for identifying molecular and biochemical events underlying the effects of feeding, occlusal changes, and tooth loss in the aging TMJ.

Expression of neurotransmitters, vasculogenesis markers and myosin heavy chain isoforms in the masseter muscle of senescence-accelerated mouse prone 8 mice.

BACKGROUND: Learning and memory deficits and pathologic changes in the hippocampus caused by toothlessness and soft diet feeding are related to reduced masseter muscle (MM) function. OBJECTIVE: Myosin heavy chain (MyHC) isoform expression in the MM also changes under different chewing conditions. The neurotransmitter calcitonin gene-related peptide (CGRP) and vascular endothelial growth factor A (VEGF-A) are involved in MM formation. However, the relationship between CGRP, VEGF-A and MyHC isoforms in the MM in the senescence-accelerated mouse prone 8 (SAMP8) strain, a model of learning and memory deficits, remains unclear. METHODS: Changes in CGRP, VEGF-A, vasculogenesis marker and MyHC isoform mRNA expression in the MMs of ageing SAMP8 and senescence-accelerated mouse resistant 1 (SAMR1) mice was investigated through quantitative real-time polymerase chain reaction (qRT-PCR) and in situ hybridization. RESULTS: qRT-PCR revealed obviously high CGRP levels in the SAMP8 mouse MM (p < .001). MyHC-IId/x mRNA expression in the MM was higher in 24-week-old SAMP8 mice than 24-week-old SAMR1 mice (p < .001) but lower in slow-MyHC SAMP8 mice than SAMR1 mice (p < .001). CGRP mRNA was observed on the muscle fibres of the SAMP8 mouse MM but not the SAMR1 mouse MM through in situ hybridization. Principal component analysis (PCA) revealed strong positive contributions of SAMP8-MyHC-IId/x, SAMP8-CGRP, SAMR1-MyHC-emb, SAMR1-CGRP, SAMR1-VEGF-A, SAMR1-CD31, SAMP8-VEGF-A, and SAMP8-CD31 in the MM at 12 and 24 weeks. CONCLUSION: Calcitonin gene-related peptide is also key for the MyHC-IId/x and slow-MyHC patterns in the MMs of SAMP8 mice.

Structural and CBCT analysis of mandibular canal microvessels expressing neurotransmitters in human cadavers.

PURPOSE: This study focused on the detailed structure of microvessels of the neurotransmitter-positive vasa nervorum of the inferior alveolar nerve, vein, and artery in the mandibular canal (MC) to obtain information for improved safety in dental treatments. We also observed the detailed structure of the MC from the mental foramen to the mandibular foramen using cone-beam computed tomography (CBCT). METHODS: In this study, mandibles from 45 sides of 23 human cadavers aged 76-104 years were examined by microscopy, immunohistochemistry, and CBCT analysis. These data were further evaluated by principal component analysis (PCA). RESULTS: The microvessels of the vasa nervorum with calcitonin gene-related peptide- and neuropeptide Y-positive reactions were classified into 5 types: large (4.19%, 28/667); irregular large (7.35%, 49/667), numerous intermediate (29.23%, 195/667), irregular intermediate (29.23%, 195/667), and scattered fine (30.0%, 200/667) microvessels. The MC showed various structures from the 3rd molar to the premolars and was also classified into three types, including complete (57.0%, 228/400), partial (33.8%, 135/400), and unclear (9.2%, 37/400), from the mandibular foramen to the mental foramen. PCA results revealed that developed capillaries were mainly localized in the molar region. CONCLUSIONS: Fine microvessels of the vasa nervorum expressing neurotransmitters are present from the molar to premolar region, which is key information for mandibular dental treatments. The different microvessel structures also indicate differences in specific characteristics between dentulous and edentulous cadavers regarding oral surgical and implant treatments.

Three-dimensional structure of the facial canal and related blood vessels and nerves in the temporal bone.

PURPOSE: There are only limited anatomical data on nerves, veins, and arteries in the temporal bone. More detailed anatomical data are required to improve planning of treatments targeting the temporal bone region. Herein, we performed a detailed analysis of the facial canal (FC) and the related carotid artery and vein. METHODS: We examined the bony structure of the middle ear and FC, jugular foramen, and carotid canal in 30 Japanese elderly donor cadavers. Three-dimensional reconstruction of the canal structure was achieved using cone beam computed tomography, while macroscopic and histological analyses were also performed. RESULTS: The FC form was classified as either straight (28%) or bent (72%). There were significant differences in the diameter of the FC and the distance between the internal jugular vein, other FC branches, and the FC. Principal component analysis (PCA) was performed for the FC using 29 factors. Two principal components significantly explained 30.9% (component 1, 18.6%; component 2, 12.3%) of the FC. Histological observation showed numerous ganglion cells and shrunken neurons in the geniculate ganglion of the facial nerve of elderly samples. CONCLUSION: FC diameter is an important contributor to the relationship between the FC and the jugular foramen. The FC and the internal jugular vein are located close to each other, which is useful information for the trans-canal surgery of the otology. Furthermore, the geniculate ganglion contains numerous ganglion cells and shrunken neurons, which may affect the FC structure during bone matrix remodeling with aging.

Clinical anatomy of the anterior and posterior hepatic plexuses, including relations with the pancreatic plexus: A cadaver study.

The poor prognosis after surgery for pancreatic cancer or extrahepatic bile duct cancer has mainly been attributed to early lymph node metastasis, as well as a high frequency of perineural invasion along the peripancreatic neural plexuses or extrahepatic bile duct plexus. However, there has been no detailed morphological description of the anterior and posterior hepatic plexuses (AHP and PHP). In addition, the concepts of the pancreatic plexus and PHP are confused by surgeons. To assess the relations of the pancreatic plexus and hepatic plexuses from the morphological, developmental, and clinical perspectives, these plexuses were dissected in 24 cadavers. The PHP was found to be completely independent of the AHP. The PHP ran behind the portal vein, with most nerve fibers ascending along the bile duct to the gallbladder and the liver or descending to the distal common bile duct and duodenal papilla. Some branches of the PHP contributed to the pancreatic plexus, corresponding to pancreatic head plexus I as defined by the Japan Pancreas Society. The differences between the PHP and pancreatic head plexus I should be understood, even though liver function is not obviously affected after PHP excision for pancreatic head cancer. Further study is needed to determine whether there are functional differences between the AHP and PHP. Clin. Anat., 33:630-636, 2020. © 2019 Wiley Periodicals, Inc.

Analysis of the development of human foetal nasal turbinates using CBCT imaging.

PURPOSE: The morphological structure of the nasal cavity (NC) is important for endoscopic surgical treatment. The location of nasal turbinates, including the superior turbinate (ST), middle turbinate (MT) and inferior turbinate (IT), are well presented during the formation of the human NC in cone beam CT (CBCT) images. There is a complex relationship between the nasal sinuses, the maxillary sinus (MS), ethmoidal sinus and sphenoid sinus, during formation of the NC structure at the morphological level. There is a need to clearly define the relationships of these nasal elements at the ossification level, during development. METHODS: We investigated the three-dimensional construction of human foetal NC elements, including ST, MT, IT and vomer, using CBCT images from 16 weeks gestation (E16) to E31 (25 foetuses) and compared it to histochemical observations (E25). RESULTS: At the stage of ossification, the studied elements are elongated in the posterior region near the sphenoidal bone, showing that the locations of the ST, MT, and IT are important during formation of the NC. CBCT analysis revealed that the horizontal and vertical directions of nasal turbinates affect the formation of the human NC. CONCLUSION: The location and elongated development of the MT is one of the most important elements for NC formation. The relationship between the nasal sinus and nasal turbine at the level of ossification may provide useful information in clinical treatment of children.

Comparison of the expression of neurotransmitter and muscular genesis markers in the postnatal male mouse masseter and trigeminal ganglion during development.

Calcitonin gene-related peptide (CGRP) is released by motor neurons and affects skeletal muscle fiber and transient receptor potential cation channel subfamily V member 1 (TRPV1), an important marker of pain modulation. However, the expression of CGRP and TRPV1 in the trigeminal ganglion (TG) during changes and in feeding patterns has not been described. We used real-time reverse transcription polymerase chain reaction and in situ hybridization to investigate the mRNA expression levels of CGRP and TRPV1 in the TG. The expression of myosin heavy-chain (MyHC) isoforms was also investigated in the masseter muscle (MM) during the transition from sucking to mastication, an important functional trigger for muscle. The mRNA and protein levels of CGRP increased in the MM and TG from postnatal day 10 (P10) to P20 in male mice. The protein levels of TRPV1 were almost constant in the TG from P10 to P20, in contrast to increases in the MM. The mRNA abundance of TRPV1 in the TG and MM was increased from P10 to P20. The localization of an antisense probe was used to count CGRP cell numbers and found to differentiate the ophthalmic, maxillary, and mandibular nerve divisions of the TG. In particular, the number of CGRP+ cells per 10,000 µm2 in the maxillary and mandibular divisions of the TG gradually changed from P10 to P20. The expression of CGRP and TRPV1 in the TG and MM and the patterns of expression of different MyHC isoforms were affected by changes in feeding during male mouse development.

Morphological observation and CBCT of the bony canal structure of the groove and the location of blood vessels and nerves in the palatine of elderly human cadavers.

PURPOSE: The greater and lesser palatine nerves and vessels supply the hard and soft palates, and the roots of these vessels and nerves run through a bony structure. However, the arrangement of blood vessels in the maxilla requires attention during clinical treatments, but detailed morphological information about changes in the greater and lesser palatine arteries and nerves during aging is unavailable. We therefore need detailed investigations of the morphology of the donor cadaver palatine using cone-beam computed tomography (CBCT) and macroscopic observations. METHODS: We investigated 72 donor cadavers using macroscopic segmentation and CBCT. The results' analysis examined differences in skull measurement parameters and differences between dentate and edentulous cases. RESULTS: The greater palatine artery and nerve showed different macroscopic arrangements in dentate and edentulous cadavers. We also classified three types of bony structures of the nerve and vessel roots in the molar regions of the palatine using CBCT images: the shallow groove, deep groove, and flat groove. The deep groove is the deepest of the three and is remarkable in edentulous elderly cadavers. CONCLUSION: This study of macroscopic and CBCT data provides information useful for planning dental implant surgeries and autogenous bone harvesting.

Promoter motifs required for c-mpl gene expression induced by thrombopoietin in CMK cells.

Thrombopoietin (TPO) and its receptor, c-Mpl, are the central regulators of megakaryocyte development and platelet production and are also crucial to regulate megakaryocytopoiesis. TPO remarkably elevated c-mpl promoter activity, while the protein kinase C (PKC) inhibitors, GF109203, H7 and Calphostin C, clearly reduced the steady level of its promoter activity.  In the present study, motifs crucial for c-mpl promoter activity induced by TPO treatment have been analyzed using a human megakaryoblastic cell line, CMK. Destruction of the -107Sp1 and the -57Sp1 sites in the c-mpl promoter enhancer region resulted in decrease of the promoter activity by 53.1% and 64.4%, respectively, and destruction of -69Ets and -28Ets elements dramatically decreased the promoter activity by 96.4% and 87.8%, respectively, while mutation of -77GATA moderately reduced the activity by 31.4%. The result was in agreement with our previous report that showed the crucial motifs in the c-mpl promoter for the promoter activity induced by PMA-treatment. This indicates that TPO-induced activation of the c-mpl promoter activity is fully modulated by transcription through a PKC-dependent pathway and the two Sp1 and two Ets motifs are crucial for the activation of the c-mpl promoter activity rather than a GATA motif in the c-mpl promoter of CMK cells.

Distribution of substance P and the calcitonin gene-related peptide in the human tensor tympani muscle.

Substance P-immunoreactive nerve fiber (SP-IR NF) and calcitonin gene-related peptide-immunoreactive nerve fiber (CGRP-IR NF) are important mediators of neurogenic inflammation and blood supply. SP-IR and CGRP-IR NFs in the tensor tympani muscle (TTM) of the human middle ear have yet to be described. In this study, the TTM, tympanic membrane, malleus in the middle ear and tensor veli palatini muscle (TVPM) were examined by whole-mount immunohistochemistry in tissue from Japanese subjects. Thirteen human cadavers (ranging in age from 46 to 90 years) were used in this study. SP-IR and CGRP-IR NFs were primarily found on vessels at the origin, insertion and belly of the surface of the TTM and on the internal surface of the tympanic membrane. These neural factors were also detected on the surface of the malleus and the insertion of the TVPM. Therefore, our results indicate that existence of the SP-IR and CGRP-IR NFs of the TTM and the TVPM may reflect muscle properties involved in pain or inflammation of the middle ear.

A new histopathological phenomenon: Pancreatic islet cell loss in the elderly population.

BACKGROUND: We observed the phenomenon of pancreatic islet cell loss (ICL) in our previous histopathological study. Multiple studies have reported that a decrease in ß-cells is correlated with diabetes or chronic pancreatitis. Few studies have reported ICL in a healthy population. METHODS: Thirty-three pancreatic tissue samples were obtained from cadavers (age: 65-104 years) who had never been diagnosed with any pancreatic diseases before death. The pancreatic body sections were used for an immunohistochemical study of pancreatic islet cells, and area calculations were performed using ImageJ to determine the degree of ICL and islet cell proportions. RESULTS: The proportion of ß-cells showed a downward trend as the degree of ICL increased (r=-0.414, P = 0.011), and the proportion of women with severe ICL was significantly higher than that of men with severe ICL (P = 0.016). The probability of severe ICL decreased with age in the population over 70 years of age (P = 0.069, linear correlation). Severe ICL may be associated with higher pancreatic intraepithelial neoplasia lesions (P = 0.059). CONCLUSION: The phenomenon of ICL in the elderly population was mainly due to pancreatic ß-cell reduction. It may be one of the direct causes of age-related diabetes.

Characteristic expression of CGRP and osteogenic and vasculogenic markers in the proximal and distal regions of the rib during male mouse development.

BACKGROUND: Neuropeptide calcitonin gene-related peptide (CGRP) is a neurotransmitter related to vasculogenesis and osteogenesis during bone formation and organ development. From the foetal period to the postnatal period, the thorax, which is necessary for lung respiration, forms. The thorax exhibits the same cartilage ossification as the bones of the extremities, but a specific system within the thorax exists as costal cartilage after birth. The relationship among CGRP, osteogenesis and vasculogenic markers in the two rib locations during thorax formation is not fully understood. MATERIALS AND METHODS: In our study, male mice were used to provide ribs under different development conditions on various embryonic days (E12. 5, E14.5, and E17.5) and postnatal days (P1 and P5). The mRNA expression levels of CGRP, vascular endothelial growth factor (VEGF-A), type 1 collagen (Col1a-1), type 2 collagen (Col2a1), neuropeptide Y (NPY), osteocalcin (OCN) and osteopontin (OPN) were analysed by qRT-PCR. We also analysed the mRNA expression of CGRP, VEGF-A and OPN by in situ hybridization. Multivariate modelling with principal component analysis (PCA) was performed to estimate the interactions among the quantitative real-time RT-PCR data. RESULTS: The mRNA expression levels of CGRP, VEGF-A, Col2a, Col1a-1, OCN, and NPY in the male mouse rib gradually increased during development. An antisense probe for CGRP mRNA was strongly detected in the central region of the mouse rib at E12.5 and the hypertrophic and ossification zones at E17.5 by in situ hybridization. VEGF-A was also located in the same region as CGRP at E12.5 and E17.5. OPN was strongly detected at the rib formation stage from E14.5 to E17.5. The expression of CGRP also differed between the proximal and distal regions of the rib at E17.5. As demonstrated by in situ hybridization, CGRP continuously participates in cartilage formation in the distal regions of the rib after birth. The PCA revealed that the mRNA expression of CGRP was related to that of Col1a-1 and VEGF-A during rib formation. CONCLUSION: This study shows that CGRP is involved in vascular and bone formation during rib development and may also be involved in cartilage formation after birth. The findings suggest that CGRP may temporarily participate in bone formation and continuously participate in cartilage formation in the rib, which may also be related to the formation of the anterior thoracic wall after birth.

Anatomical study of the human discomallear ligament using cone beam computed tomography imaging and morphological observations.

In the present study, the human discomallear ligament (DML) was observed in structures at both macroscopic and cone beam computed tomography levels. Assessments were made regarding the distribution of calcitonin-gene-related peptide (CGRP), protein gene-product (PGP) 9.5, and substance P (SP) of the DML based on immunohistochemical analyses of the anatomical properties of jaw movements using 27 Japanese human cadavers (mean, 79.3 +/- 8.6 years; male, 74.9 +/- 8.0; female, 82.8 +/- 7.5). The DML of the anterior region was connected to the TMJ disc. The DML of the posterior region was attached to both the head and the anterior process of the malleus through the petrotympanic fissure, which formed a narrow channel. The structure of the petrotympanic fissure through the DML was attached to the malleus, and this structure was associated with the mobility of the malleus. In the anterior and posterior parts of the disc-associated connective tissue of the DML, CGRP-, PGP9.5- and SP-positive nerve fibers were located around numerous blood vessels, a condition which may be correlated with chronic pain syndrines disorders and the auditory system.

Analysis of vascular distribution and growth factors in human gingival tissue associated with periodontal probing depth.

SUMMARY: Vascular endothelial growth factor (VEGF) is a key regulator of blood vessel endothelium. Tissue levels of this angiogenesis marker are unknown in human gingival tissue, as is the correlation between vascular growth factors and hypoxia-inducible factor. We examined the expression of VEGF, type III tyrosine kinase receptors (VEGF-R2), platelet-endothelial cell adhesion molecule (CD31) and hypoxia-inducible factor (HIF) mRNA from human gingival tissue of the oral cavity. Tissue samples were from a small quantity of gingival sample biopsy with gingival sulcular depth (GSD) < 2 mm (Group 1), 2 to 4 mm (Group 2), and > 4 mm (Group 3). We found that the levels of VEGF-R2, CD31 and HIF mRNA were higher in the gingival tissue of Group 2 than that of Group 1, and VEGF in the Group 3 was also higher than that of Group 1. The different mRNA levels of these markers may reflect the mRNA levels reflect the vasculature state of gingival tissue based on GSD. VEGF-R2 and HIF also indicate the presence of an elongated blood vessel in the gingival tissue. In the early stage of angiogenesis, VEGF-R2 leads to expression of VEGF, and HIF-1 mediates increased VEGF expression in response to hypoxia in swollen tissues or during the expansion of periodontal tissues, which is useful in the early diagnosis of periodontal diseases.

A morphological study of the blood vessels associated with periodontal probing depth in human gingival tissue.

Gingival tissues in human cadavers were examined the blood vessel diameter in the depths of the gingival pockets such as three groups: gingiva adjacent to a sulcus of 2 mm (Group 1); gingiva adjacent to a 2-4-mm sulcus (Group 2); and gingiva adjacent to a sulcus of > 4 mm (Group 3). A meaningful significant difference was seen observed in gingival pocket side, intermediate and outer layer side regions of the gingiva. A meaningful significant difference was seen found in intermediate part and the outer layer of the gingiva in Group 3. Other gingival biopsies were performed on a human body donation specimen to examine CD-31 positive endothelial cells of blood vessels by an immnohistochemical method. Our results suggest that the periodontal probing depth reflect the blood vessel organization of human gingival tissue.

Analysis of the mylohyoid nerve in elderly Japanese cadavers for dental implant surgery.

OBJECTIVES: Injury to the mandibular nerve (MN) branches may cause pain and irregular occlusal movement during mastication after mandibular dental treatments. Growing evidence indicates that the calcitonin gene-related peptide (CGRP) plays a key role in the development of peripheral sensitization and the associated enhanced pain, suggesting it may be a sign to ensure a safe and reliable dental implant treatment. Our focus was on the distribution of the MN branches and their communication with the lingual nerve (LN), the localized expression of CGRP, and the identification of a pain area related to the mylohyoid muscle (MM) fascia in the mandibular floor. MATERIAL AND METHODS: In this study, MM samples from 440 sides of 303 human cadavers aged 61-103 years were examined microscopically and immunohistochemically. These data were further evaluated by the use of principal component analysis. RESULTS: A complex but weak attachment site was identified for the fascia of the MM. CGRP expression was mainly located in small vessels and was scattered throughout the whole fascia of the MM. Communication between the MN and LN was found in 62.5% (275/440) of the samples. The results from the principal component analysis showed that the positive contributions were from the descending branch in the premolar region (correlation coefficient value R = 0.665), the ascending branch in the molar region (R = 0.709) and the intermediate branch of the digastric branch (R = 0.720) in component 1. In the fascia off the MM, strongly labeled CGRP-positive cells were also found around the blood vessels and the nerve. CONCLUSIONS: The findings reported in this study indicate that there is a risk of damage when pulling the fascia off the MM at the border of the molar and premolar regions during dental implant surgery.

Comparison of CGRP distributions in the maxillary sinus and trigeminal ganglion between elderly dentulous and edentulous humans.

Thickening of the Schneiderian membrane (SM, mucosa of the maxillary sinus) appears in the paranasal sinus. Information on SM thickening is available for patients receiving sinus lift treatments, which is a risk factor for SM excretory dysfunction. However, more information is needed on the structure of the SM and the relationship between the maxilla sinus and palatine with the alveolar bone and the SM for dental implant treatment in the human maxilla. One hundred twenty-six sides of the maxilla from 71 cadavers were subjected to cone-beam CT (CBCT) analysis and macroscopic and immunohistochemical observations in this study. A thickened SM was mainly observed in the middle region of the basal layer of the maxillary sinus (MS). Strong calcitonin gene-related peptide (CGRP)-positive reactions were observed in the alveolar bone, oral mucosa, mucosa of the maxillary sinus, and trigeminal ganglion (TG) cells in dentulous samples compared with edentulous samples. TG cells play important roles in delivering CGRP through axons to the mucosal gland and in regulating the maxilla-related thickening of the SM. These data could help determine CGRP functions in the mucosal gland and bone formation between dentulous and edentulous samples and indicate that CGRP may pass from the TG to the maxillary sinus glands.

A new APE1/Ref-1-dependent pathway leading to reduction of NF-kappaB and AP-1, and activation of their DNA-binding activity.

APE1/Ref-1 is thought to be a multifunctional protein involved in reduction-oxidation (redox) regulation and base excision DNA repair, and is required for early embryonic development in mice. APE1/Ref-1 has redox activity and AP endonuclease activity, and is able to enhance DNA-binding activity of several transcription factors, including NF-kappaB, AP-1 and p53, through reduction of their critical cysteine residues. However, it remains elusive exactly how APE1/Ref-1 carries out its essential functions in vivo. Here, we show that APE1/Ref-1 not only reduces target transcription factors directly but also facilitates their reduction by other reducing molecules such as glutathione or thioredoxin. The new activity of APE1/Ref-1, termed redox chaperone activity, is exerted at concentration significantly lower than that required for its redox activity and is neither dependent on its redox activity nor on its AP endonuclease activity. We also show evidence that redox chaperone activity of APE1/Ref-1 is critical to NF-kappaB-mediated gene expression in human cells and is mediated through its physical association with target transcription factors. Thus, APE1/Ref-1 may play multiple roles in an antioxidative stress response pathway through its different biochemical activities. These findings also provide new insight into the mechanism of intracellular redox regulation.

Understanding the formation of maxillary sinus in Japanese human foetuses using cone beam CT.

The formation of the maxillary sinus (MS) is tied to the maturation of the craniofacial bones during development. The MS and surrounding bone matrices in Japanese foetal specimens were inspected using cone beam computed tomography relative to the nasal cavity (NC) and the surrounding bones, including the palatine bone, maxillary process, inferior nasal concha and lacrimal bone. The human foetuses analysed were 223.2 ± 25.9 mm in crown-rump length (CRL) and ranged in estimated age from 20 to 30 weeks of gestation. The amount of bone in the maxilla surrounding the MS increased gradually between 20 and 30 weeks of gestation. Various calcified structures that formed the bone matrix were found in the cortical bone of the maxilla, and these calcified structures specifically surrounded the deciduous tooth germs. By 30 weeks of gestation, the uncinate process of the ethmoid bone formed a border with the maxilla. The distance from the midline to the maximum lateral surface border of the MS combined with the width from the midline to the maximum lateral surface border of the inferior nasal concha showed a high positive correlation with CRL in Japanese foetuses. There appears to be a complex correlation between the MS and NC formation during development in the Japanese foetus. Examination of the surrounding bone indicated that MS formation influences maturation of the maxilla and the uncinate process of the ethmoid bone during craniofacial bone development.

PKC plays a crucial roles in c-mpl gene expression in megakaryoblastic cells.

Thrombopoietin is the cytokine involved in megakaryopoiesis and its receptor (c-Mpl) is considered to regulate development of megakaryocyte. In this research, to elucidate the underlying mechanisms of c-mpl gene expression in megakaryoblastic cells, we investigated the effect of a protein kinase C (PKC) on c-mpl promoter activity in a time-dependent manner. PKC is a member of a family of serine/threonine protein kinases in the cytosol involved in cell growth and differentiation. Phorbol 12-myristate 13-acetate (PMA) is known as PKC activator, significantly enhanced the c-mpl promoter activity and PKC inhibitor, 2-methylpiperazine dihydrochloride (H-7) suppressed the up-regulation of PMA-induced promoter activity and this effect decreased in a time-dependent manner. These results clearly suggest that in megakaryoblastic cells, PKC plays the crucial role in the initiation of up-regulation of PMA-induced c-mpl promoter activity.