Biomedical subjects

Keiichi Akita

Publications and source records attributed to Keiichi Akita.

At least 19 recordsLinked to original sources

PubMed2007

Bony eminence on the middle cranial fossa corresponding to the temporomandibular joint.

We report a nameless bony eminence over the temporomandibular joint (TMJ) and its possible clinical significance. Forty-two half heads of 21 UK Caucasian cadavers (61-95 years old, mean 84.3 +/- 8.2 years, male:female = 11:10) were used to investigate the surface of the middle cranial fossa (MCF) over the TMJ. The thickness of the bony roof of the glenoid fossa was also measured. A bony eminence over the glenoid fossa was observed in half of the specimens. Some showed a complete oval bulge, which completely reflected the contour of the glenoid fossa. The others showed a bony bulge, which partially reflected that contour. The mean (+/-SD) thickness of the bone in the roof of glenoid fossa was 1.5 +/- 1.2 mm. The mean bony thickness of specimens showing the eminence was 0.8 +/- 0.5 mm, whereas it was 2.3 +/- 1.2 mm in specimens without an eminence. These differences were statistically significant (P < 0.01). The osteological features we describe may be relevant to certain clinical problems. Traumatic dislocation of mandibular condyle, for example, might relate to a weakness of the glenoid fossa.

Aged↗

PubMed2006

Developmental expression of the chick four-jointed homologue.

Four-jointed is a type II transmembrane protein that is thought to be cleaved to give rise to a secreted protein. In Drosophila, four-jointed controls outgrowth, vein patterning, and bristle polarity in the developing limb together with the polarity of the ommatidia in the developing eye. In Drosophila and mice, Fj is regulated by notch signaling. Here, we have determined the expression of the chick four-jointed (fjx) homologue during embryonic development. We show that fjx is expressed in the limb bud; facial primordia; the proliferating zone of the lens, feather buds, the neural tube; and neural crest derivatives such as the dorsal root ganglia. Analysis of the fjx expression in the developing limb bud showed that initially fjx is expressed throughout the limb bud, but as the limb develops, highest levels of fjx transcripts are found distally. However, by stage 27, fjx expression is predominantly found in the central core of the limb bud. Finally, fjx expression becomes confined to the developing tendons, ligaments, articular cartilage, and arteries but not the veins. Comparison with scleraxis (scx), a marker of tendons and ligaments, revealed that they are coexpressed in the majority of tendons but that fjx is expressed after scx, when the tendons have begun to differentiate. These data suggest that fjx has two roles during limb development: the first controlling outgrowth and the second tissue differentiation.

Amino Acid Sequence↗

PubMed2005

Expression and function of Bapx1 during chick limb development.

The homeobox-containing transcription factor Bapx1 (also known as Nkx3.2) is crucial for development of the axial skeleton and parts of the chondrocranium. Here we describe the detailed expression of Bapx1 during chick limb development and show that in contrast to its expression in the axial skeleton, Bapx1 is expressed after the commitment to chondrogenesis. Bapx1 is initially expressed throughout the developing skeletal elements prior to the overt differentiation of the distinct chondrogenic layers. Once distinct layers (proliferating, prehypertrophic and hypertrophic) have formed, Bapx1 expression is restricted to the proliferating chondrocytes. Bapx1 transcripts are excluded from the articular cartilage. A second homeobox-containing transcription factor, Barx1, is expressed in a complementary fashion in the developing joint and articular cartilage. Interestingly, in vitro functional analyses showed that Bapx1 overexpression in micromass cultures increased both matrix production and nodule number suggesting that Bapx1 is sufficient to promote chondrogenesis in the limb. In contrast, Barx1 had the opposite effect on nodule number suggesting that it has an inhibitory effect on chondrogenic initiation consistent with its expression in the developing joint. A slight increase in matrix levels was also observed consistent with its expression in the articular chondrocytes. Finally, we show that Bapx1 is also expressed in the soft tissues such as the developing tendons, muscle sheaths and surrounding mesenchyme, and therefore may have additional as yet uncharacterized roles in limb morphogenesis.

Amino Acid Sequence↗

PubMed2005

Comparative anatomical study of the autonomic cardiac nervous system in macaque monkeys.

The main aim of this study was to clarify the general morphology of the autonomic cardiac nervous system in macaque monkeys. A submacroscopic comparative anatomical study of the autonomic cardiac nervous system was performed by examining 22 sides of 11 bodies of four species of macaque monkeys, including some previously unreported species (pig-tailed and stump-tailed monkeys), under a surgical stereomicroscope. The following results were obtained. 1) The basic arrangement of the autonomic cardiac nervous system is constant in all examined macaques. 2) A superior cardiac nerve originating from the superior cervical ganglion was not observed, whereas the thoracic cardiac nerve originating from the sympathetic trunk/ganglia under the cervicothoracic ganglion was rarely observed in all the examined macaques. 3) The main cardiac nerve is the middle cardiac nerve originating from the middle cervical ganglion, similar to the situation in humans. 4) Although the superior, inferior, and thoracic cardiac branches of the vagus nerve were consistently observed, the left thoracic cardiac branch is rarely absent because of its lower origin to the heart. 5) The cranial autonomic nerves tend to distribute into the heart medially (arterial porta), and the caudal autonomic nerves tend to distribute into the heart laterally (venous porta). To comprehend the comparative morphological and evolutionary changes more completely, these results were compared with our previous studies and some references. Consequently, differences in the sympathetic cardiac nerves of macaques and humans are recognized, in spite of the similar morphologies of the vagal cardiac branches. These differences include the composition of the cervicothoracic ganglion, the lower positions of the middle cervical and cervicothoracic ganglia, and the narrow range for the origin of the cardiac nerves in macaques compared to that in humans.

Anatomy, Comparative↗

PubMed2005

Purification and characterization of an esterase hydrolyzing monoalkyl phthalates from Micrococcus sp. YGJ1.

An esterase that specifically hydrolyzes medium-chain (C(3)-C(5)) monoalkyl phthalates was purified from phthalate-grown Micrococcus sp. YGJ1. The enzyme activity was split into two fractions by hydrophobic chromatography on Phenyl Sepharose, and the enzymes were purified to homogeneity from each fraction. The purified enzymes showed similar properties with respect to molecular mass (60 kDa), subunit molecular mass (27 kDa), N-terminal amino acid sequence, optimal pH (about 7.5), temperature-dependence, substrate specificity, and inhibitor susceptibility. The enzymes showed no activity toward various dialkyl phthalates or aliphatic carboxyl esters. 2-Mercaptoethanol effectively protected the enzymes from spontaneous inactivation. Diethylpyrocarbonate, p-chloromercuribenzoate, Hg(2+), and Cu(2+) strongly inhibited the enzymes, while phenylmethylsulfonyl fluoride produced weak inhibition, and various metal chelating reagents were ineffective. These findings show that the enzymes bear a close resemblance to the putative phthalate ester hydrolase (PehA) of Arthrobacter keyseri 12B.

Carboxylic Ester Hydrolases↗

PubMed2005

Surgical anatomy of the innervation of the major duodenal papilla in human and Suncus murinus, from the perspective of preserving innervation in organ-saving procedures.

OBJECTIVES: Few studies have focused on the detailed surgical anatomy of the innervation of the major duodenal papillary region, especially in relation to duodenum-preserving pancreatic head resection (DPPHR) and its modified procedures, which is crucial to preserving the innervation of the papillary region. The aim of this study is to clarify the neural distribution of the major duodenal papilla in humans. METHODS: The pancreas, duodenum, and surrounding structures were dissected in 10 cadavers and immersed in a 0.001% solution of alizarin red S in ethanol to stain the peripheral nerves. The details of the innervation in the above areas were confirmed using a binocular microscope. Similarly, the distribution in 10 Suncus murinus was examined by whole mount immunohistochemistry method with antineurofilament protein antibody. RESULTS: The innervation of the papillary region in humans involved 2 systems. One arose from the celiac plexus, which through the anterior hepatic plexus running along the arcades of the superior pancreaticoduodenal arteries and through the posterior hepatic plexus running along or accompanying the common bile duct (CBD) or Wirsung's duct, innervated the papillary region. The other arose from the superior mesenteric plexus wound around the arcades of the inferior pancreaticoduodenal arteries innervating the papillary region. The results in S. murinus supported those in humans. CONCLUSIONS: We emphasize the importance of the nervus-preserving of the major duodenal papilla and CBD by a suitable pancreatic head remnant, preserving the pancreaticoduodenal arterial arcades and avoiding kocherization of the CBD in DPPHR and its modified procedures.

Aged↗

PubMed2004

Premature regression of the leg apical ectodermal ridge in the Japanese chick wingless mutant.

The autosomal dominant Japanese wingless mutant has varying degrees of wing and leg truncations. The wing defects range from complete loss to negligible defects, whereas leg abnormalities are usually restricted to loss of the phalanges. Further analyses of the mutant focusing on the leg, which has been relatively uncharacterized, were performed. The expression pattern of Fgf8, a marker gene for the apical ectodermal ridge (AER) that controls outgrowth of the limbs, revealed premature regression at stage 28. Electron microscopy study showed abnormalities in the basement membrane all through the AER in the same stage. In the mutant, cell death was observed in the mesenchyme underlying AER between stages 31 and 32, although in the wild-type leg, AER regression and cell death occurred almost simultaneously at stages 33-34. To know if the cell death and cessation of the outgrowth are common mechanisms of wild-type and the mutant, we removed the AER in wild-type embryos at stage 28 and followed the fate of the limb. This also resulted in premature cell death 48 h after AER removal (equivalent to stage 32) and limb truncations similar to those observed in mutant limbs. To confirm whether either AER or underlying mesenchyme is responsible for the truncation, transplantation of the AER between the wild-type and the mutant was performed. This revealed that AER is the defective tissue in this mutant.

Animals↗

PubMed2004

Spatiotemporal distribution of apoptosis during normal cloacal development in mice.

To understand normal cloacal developmental processes, serial sagittal sections of mouse embryos were made every 6 hrs from embryonic day 11.5 (E11.5) to E13.5. During cloacal development to form the urogenital sinus and anorectal canal, fusion of the urorectal septum with the cloacal membrane was not observed, and the ventral and dorsal parts of the cloaca were continuously connected by the canal until disappearance of the cloacal membrane to open the vestibule formed by the urogenital sinus and anorectal canal to the outside at E13.5. Ventral shifting of the dorsal part of the cloaca was observed until E12.5. The dorsal part was transformed in accordance with ventral shifting. In addition, apoptosis was seen to occur around the dorsal part. However, from E12.25, apoptotic cells are observed in a linear arrangement in the urorectal septum just ventral to the peritoneal cavity. Interestingly, extension of this line reaches the area of the cloacal membrane disintegrated by apoptosis. The present findings suggest that in the early stages (until E12.0), distribution of apoptosis in mesenchyme around the dorsal part of the cloaca might be strongly related to the transformation and ventral shifting of this part. Conversely, the apoptosis pattern in urorectal septum mesenchyme in later stages (from E12.0) might be involved in transformation of the urorectal septum and disintegration of the cloacal membrane.

Aging↗

PubMed2004

Pes anserinus: layered supportive structure on the medial side of the knee.

The pes anserinus is composed of a combination of tendinous insertions of the sartorius, gracilis and semitendinosus muscles. Precise knowledge of the structures on the medial side of the knee and the relationships between fascia and tendons is critical for diagnosis, surgery, and the development of improved operative procedures of the knee. To obtain precise data on the layered structures associated with the fascia cruris on the medial side of the knee and the fibrous bundles attached to them, we dissected nine legs of five adult cadavers. We observed a superficial longitudinal fibrous bundle on the superficial surface of the sartorius and a deep longitudinal fibrous bundle on the aponeurotic membrane covering the tendon of the gracilis muscle. The distal parts of the tendons of the gracilis and semitendinosus were found to have aponeurotic membranes, and these membranes were fused with the fascia cruris. These two longitudinal fibrous bundles and the aponeurotic membranes from the gracilis and semitendinosus tendons fused with the fascia cruris, and a small tendinous expansion from the semimembranosus muscle fused with the aponeurotic membrane from the semitendinosus tendon and tibial collateral ligament as well as the fascia covering the medial head of the gastrocnemius and fascia cruris. Based on the considerable tension from the sartorius, gracilis, semitendinosus, semimembranosus and gastrocnemius muscles, these bundles, membranes, and muscles may act as a complex tensor fasciae cruris muscle and play a significant role as stabilizers of the medial side of the knee joint in the upright posture.

Cadaver↗

PubMed2004

Penetration of muscles by branches of the mandibular nerve: a possible cause of neuropathy.

We carried out detailed dissections of the branches of the mandibular nerve and muscles innervated by these branches to investigate their positional relationships. We made the following observations: 1) small branch of the auriculotemporal nerve penetrated the lateral pterygoid muscle; 2) the entire lingual nerve penetrated the medial pterygoid muscle; and 3) branch of the mylohyoid nerve penetrated the mylohyoid muscle and communicated with the submandibular ganglion. No detailed descriptions of these nerve branches have been reported previously. The existence of these nerve branches that penetrate muscles might result in the neuralgic pain in the trigeminal region when such pain is of unknown origin.

Cadaver↗

PubMed2004

Contributions of the hypoglossal nerve to the innervations of the recti capiti lateralis and anterior.

We dissected five Japanese cadavers (three males, two females) to investigate the innervations of the anterior vertebral muscles. According to our observations, it could be considered that the hypoglossal nerve would participates in the innervations of the recti capiti lateralis and anterior. In addition, we observed the small muscle bundle spanning between the recti capiti lateralis and anterior, which was not reported in previous studies as far as we know. This bundle received a branch of the hypoglossal nerve or the first cervical nerve. Based on the morphology and the innervation pattern, this bundle was considered to have close relationships with the recti capiti lateralis and anterior, especially with the former muscle.

Cadaver↗

PubMed2004

Cellular localization of endocrine cells in the adult pancreas of the house musk shrew, Suncus murinus: a comparative immunocytochemical study.

The right and left lobes of the pancreas in the house musk shrew, Suncus murinus, were found to be completely separated. A morphologic study of the pancreas in S. murinus in terms of the blood supplies and innervation of the right and left lobes was performed in our previous study. It revealed clearly different blood supply and innervation patterns in the right and left lobes, suggesting that the right lobe of the pancreas corresponded to the ventral pancreas, and the left lobe related to the dorsal pancreas. To test this perspective from the histology, in this study, we investigated the immunolocalization of the cells of Langerhans islets in the pancreas of the animal. The distribution of insulin-, glucagon-, somatostatin-, and pancreatic polypeptide (PP)-secreting cells of the right and left lobes of the pancreas was examined in 10 animals. The glucagon-immunoreactive cells were distributed in both the right and left lobes. The PP-immunoreactive cells were extremely abundant in the right lobe and distributed throughout almost all the islets of Langerhans in the right lobe. By contrast, in the left lobe, immunoreactive PP cells were absent in the islets of Langerhans, and only very few immunoreactive PP cells were scattered in the exocrine parenchyma in part of the specimens. Therefore, these findings support our previous studies, and showed that the right and left lobes of the S. murinus pancreas could be related to an embryological origin from the ventral and dorsal pancreatic primordium, respectively, and that the S. murinus pancreas is suitable as a new experimental model to study the development of the human pancreas.

Animals↗

PubMed2004

Interactions between FGF and Wnt signals and Tbx3 gene expression in mammary gland initiation in mouse embryos.

Interactions between Wnts, Fgfs and Tbx genes are involved in limb initiation and the same gene families have been implicated in mammary gland development. Here we explore how these genes act together in mammary gland initiation. We compared expression of Tbx3, the gene associated with the human condition ulnar-mammary syndrome, expression of the gene encoding the dual-specificity MAPK phosphatase Pyst1/MKP3, which is an early response to FGFR1 signalling (as judged by sensitivity to the SU5402 inhibitor), and expression of Lef1, encoding a transcription factor mediating Wnt signalling and the earliest gene so far known to be expressed in mammary gland development. We found that Tbx3 is expressed earlier than Lef1 and that Pyst1 is also expressed early but only transiently. Patterns of expression of Tbx3, Pyst1 and Lef1 in different glands suggest that the order of mammary gland initiation is 3, 4, 1, 2 and 5. Consistent with expression of Pyst1 in the mammary gland, we detected expression of Fgfr1b, Fgf8 and Fgf9 in both surface ectoderm and mammary bud epithelium, and Fgf4 and Fgf17 in mammary bud epithelium. Beads soaked in FGF-8 applied to the flank of mouse embryos, at a stage just prior to mammary bud initiation, induce expression of Pyst1 and Lef1 and maintain Tbx3 expression in flank tissue surrounding the bead. Grafting beads soaked in the FGFR1 inhibitor, SU5402, abolishes Tbx3, Pyst1 and Lef1 expression, supporting the idea that FGFR1 signalling is required for early mammary gland initiation. We also showed that blocking Wnt signalling abolishes Tbx3 expression but not Pyst1 expression. These data, taken together with previous findings, suggest a model in which Tbx3 expression is induced and maintained in early gland initiation by both Wnt and Fgf signalling through FGFR1.

Animals↗

PubMed2004

Spacing patterns on tongue surface-gustatory papilla.

The dorsal surface of the mammalian tongue is covered with four kinds of papillae, fungiform, circumvallate, foliate and filiform papillae. With the exception of the filiform papillae, these types of papillae contain taste buds and are known as the gustatory papillae. The gustatory papillae are distributed over the tongue surface in a distinct spatial pattern. The circumvallate and foliate papillae are positioned in the central and lateral regions respectively and the fungiform papillae are distributed on the anterior part of the tongue in a stereotyped array. The patterned distribution and developmental processes of the fungiform papillae indicate some similarity between the fungiform papillae and the other epithelial appendages, including the teeth, feathers and hair. This is because 1) prior to the morphological changes, the signaling molecules are expressed in the fungiform papillae forming area with a stereotyped pattern; 2) the morphogenesis of the fungiform papillae showed specific structures in early development, such as epithelial thickening and mesenchymal condensation and 3) the fungiform papillae develop through reciprocal interactions between the epithelium and mesenchymal tissue. These results led us to examine whether or not the early organogenesis of the fungiform papillae is a good model system for understanding both the spacing pattern and the epithelial-mesenchymal interaction during embryogenesis.

Animals↗

PubMed2003

Morphological evidence of the importance of epithelial tissue during mouse tongue development.

The morphogenesis of fungiform papillae occurs in a stereotyped pattern on the dorsal surface of the tongue in mice from embryonic day 12 (E12) to E17. The histological results and ultrastructural observations showed the development of specific structures in the epithelium into fungiform papillae. Prior to the morphological changes, the Bmp-4 and Shh transcripts are expressed in a restricted area on the dorsal surface. These results suggest that the development of fungiform papillae requires an epithelium and mesenchyme interaction during morphogenesis. In order to obtain direct evidence of the epithelium and mesenchyme interaction during tongue papillae morphogenesis, the formation of fungiform papillae was examined after a recombination assay. In order to confirm the epithelium and mesenchyme interactions during the early development of the mouse tongue, a recombination assay was conducted after the recombination assay at E12.5 and E13.5 for 2 days using an in vitro organ culture. From the recombination assay results, the E13.5 epithelial portion of the fungiform papillae could determine the position of the newly formed fungiform papillae with the epithelial signaling molecules. E13.5 was a critical stage for fungiform papillae morphogenesis. Fungiform papillae can be considered to be small epithelial appendages, which are formed via the epithelium and mesenchyme interactions.

Animals↗

PubMed2003

Anatomical study of the pancreas in the house musk shrew (Suncus murinus), with special reference to the blood supply and innervation.

To examine the macroscopic structure, blood supply, and innervation of the pancreas in the house musk shrew (Suncus murinus), we performed gross anatomical dissection and whole-mount immunostaining of the autonomic nerve of Suncus pancreases based on neurofilament protein (NFP) immunoreactivity. The adult Suncus pancreas is clearly separated into right and left lobes that are not fused. The right lobe of the Suncus pancreas is located in the dorsum of the duodenum and to the right of the common bile duct independently. The right lobe is supplied by branches of the superior mesenteric artery, and is innervated by branches that originate from the superior mesenteric plexus and run along the arterial branches of the superior mesenteric artery. The left lobe occupies 9/10 of the entire pancreas and is located to the left of the common bile duct. It is supplied mainly by branches of the splenic and common hepatic arteries, and is innervated by branches that originate from the celiac plexus and run along the splenic and common hepatic arteries. According to previous studies on the blood supply and innervation of the human pancreas, the right and left lobes of the Suncus pancreas correspond to the pancreatic parts derived from the ventral and dorsal pancreatic buds. The current results suggest that the Suncus pancreas is a suitable experimental model for studying the development of the human pancreas.

Animals↗

PubMed2003

Topographic anatomy of the male perineal structures with special reference to perineal approaches for radical prostatectomy.

AIM: Although perineal approaches for radical prostatectomy have recently gained renewed attention as excellent methods for minimally invasive surgery, the most commonly used techniques, Belt's and Young's approaches, have inadequacies regarding the topographical relationship between the rectourethral and levator ani muscles. METHODS: Using macroscopic observations of sagittal slices of 27 male pelvises and smooth muscle immunohistochemical staining of semiserial sections of another eight pelvises, we investigated the topographical anatomy of the perineal structures and their interindividual variations in elderly Japanese men. RESULTS: The inferomedial edge of the levator ani was located 5-15 mm lateral to the midsagittal plane in an area between the urethra and the rectum. The rectourethral smooth muscle had a superoinferior thickness of 5-10 mm and occupied a space between the right and left levator slings. The levator was adjacent to, or continuous with, the striated anal sphincters. A thick connective tissue septum, composed of smooth muscle, was evident between the rectal smooth muscle and the anal sphincter-levator ani complex. CONCLUSION: Because the connective tissue septum guides the surgeon's finger upwards towards the rectoprostatic space, Belt's approach appears relatively easy; however, rectal injury can sometimes occur if the surgeon loses this guidance. In contrast, if the levator edge is identified as the first step in Young's approach, the rectourethral muscle can be precisely divided, leaving a 3-5-mm margin from the rectum and sphincter-levator complex. Clinical investigations are now required to modify Young's approach based on the present results.

Aged↗

PubMed2003

Estimation of the endolymphatic sac and vestibular aqueduct using magnetic resonance imaging.

OBJECTIVE: To evaluate the diagnostic accuracy of magnetic resonance imaging for assessment of the endolymphatic sac and vestibular aqueduct. STUDY DESIGN: Imaging and histological study of the cadaver. METHODS: Five cadavers were studied by a 1.5-T magnetic resonance imaging system with a 3-inch-diameter surface coil. Magnetic resonance imaging scans were obtained with proton density-weighted and T2-weighted fast spin-echo sequences. Histological sections were made with an epoxy resin-embedding method and were compared with magnetic resonance imaging scans. RESULTS: The visibility of the endolymphatic sac on both sequences corresponded well to the presence of the endolymphatic sac on histological sections. On the histological sections, the width of the external aperture of vestibular aqueduct (endolymphatic sac including surrounding connective tissue) was 0.96 +/- 0.18 mm (mean +/- SD) and the width of lumen of endolymphatic sac at the same point was 0.47 +/- 0.17 mm. The width of the endolymphatic sac was 1.02 +/- 0.19 mm on proton density-weighted images and was 0.81 +/- 0.15 mm on T2-weighted images. The widths of endolymphatic sac measured on proton density-weighted image and those of vestibular aqueduct on histological section did not show statistically significant differences (P >.05). On the other hand, the endolymphatic sac as measured on T2-weighted image tended to be smaller than the vestibular aqueduct (P <.05) and tended to be larger than the lumen of the endolymphatic sac (P <.0005). CONCLUSION: Both sequences can precisely depict the endolymphatic sac; however, the proton density-weighted image is a more appropriate indicator of the actual anatomical configuration of the endolymphatic sac with surrounding connective tissue and vestibular aqueduct.

Aged↗