Hiromitsu Ezure

Morphology of the lateral ligament in the human temporomandibular joint

The morphology of the lateral ligament of the human temporomandibular joint is of two types: ligamentous and without distinct structure. Under the scanning electron microscope, a sheath-like structure that contained bundles of collagen was mainly found in the posterior region of the lateral ligament. Analysis of macromolecular components revealed that type III collagen was mainly present on the collagenous framework of the sheath-like structure. Type I collagen, laminin, and tenascin were found in the framework of the sheath-like structure. Supported collagenous bundles and the distribution of macromolecular components might be related to the stability of the temporomandibular joint. The sheath-like structure and other components of the lateral ligaments store energy and protect the capsule from stress and tension during movements of the jaw.

Development of the human lateral cuneate nucleus: a morphometric evaluation

The morphometric development of the human lateral cuneate nucleus was examined in nine fetuses and neonates at 18-40 weeks of gestation, a 2-month-old infant and a 63-year-old adult. The authors observed serial sections of the brain containing lateral cuneate nucleus and measured the volume of nuclear column and the number, cell body area and perimeter of neurons using a microscope with a drawing tube and an image-analyzing computer system. A morphometric evaluation revealed that a turning point in the development of the human lateral cuneate nucleus occurring at 30 WG, as this marks the beginning of a gradual increase in the average area and average perimeter; And it is the point at which the neuropil index suddenly increases sharply, to fall back down to lower levels afterwards. The establishment of a neuronal connection between the lateral cuneate nucleus and the cerebellum, which is necessary for proper performance of movements in the upper part of the body.

Presynaptic protein Synaptotagmin1 regulates the neuronal polarity and axon differentiation in cultured hippocampal neurons

BackgroundHippocampal neurons in the brain polarize to form multiple dendrites and one long axon. The formation of central synapses remains poorly understood. Although several of the intracellular proteins involved in the clustering of central neurotransmitter receptors and ion channels have been identified, the signals involved in pre- and postsynaptic differentiation remain elusive. Synaptotagmin1 is an abundant and important presynaptic vesicle protein that binds Ca2+ (J Biol Chem 277:7629–7632, 2002) in regulation of synaptic vesicle exocytosis at the synapse. Synapse consists of the formation of synaptic connections and requires precise coordination of Synaptotagmin1. It was reported Synaptotagmin1 plays an important roles in the formation of axonal filopodia and branches in chicken forebrain neurons (Dev Neurobiol 73:27–44, 2013). To determine if Synaptotagmin1 could have a role in formation of axon in hippocampal neurons, we investigated the effects of Synaptotagmin1 overexpression and knockdown using the shRNA on the growth and branching of the axons of primary hippocampal neurons. We showed that overexpression of Synaptotagmin1 leads to abnormal multiple axon formation in cultured rat hippocampal neurons.ResultsWe first examined the effects of Synaptotagmin1 on the numbers of axon and dendrites. We found that the overexpression of Synaptotagmin1 led to the formation of multiple axons and induced an increase in the number of endogenous postsynaptic protein Homer1c clusters in cultured hippocampal neurons. Endogenous initial segment of axon was detected with anti-sodium channel (anti-NaCh) antibody and with anti-Tau1 (J Neurosci 24: 4605–4613, 2004). The endogenous initial segment of axon was stained with anti-NaCh antibodies and with anti-Tau1 antibodies. Then the numbers of prominence dyed positive were counted as axon. We attempted to specifically knockdown the endogenous Synaptotagmin1 with small hairpin RNAs (shRNAs). To further dissect the functions of endogenous Synaptotagmin1 in neuronal polarity, we used the shRNA of Synaptotagmin1 that specifically blocks the existence of endogenous Synaptotagmin1. When the shRNA of Synaptotagmin1 was introduced to the cells, the number of axons and dendrites did not change.ConclusionsThese results indicate that the accumulation of Synaptotagmin1 may play an important role in axon/dendrite differentiation.

Morphometric and quantitative evaluation of the gastroepiploic artery

BACKGROUND The gastroepiploic artery (GEA) has been described in various ways by anatomical texts and surgical manuals. Currently, there are no studies that have investigated the thickness and length of GEA using gross anatomical methods. In the present study, we measured the length, circumference, area, and major axis of GEA, and quantitatively evaluated the differences between right and left GEA (RGEA and LGEA), using gross anatomical and morphometric methods for the first time. MATERIALS AND METHOD Seventeen cadavers were selected. The median age of the cadavers was 82 years. We observed and evaluated GEA with naked eyes, as well as under a stereoscopic microscope. RESULTS RGEA was significantly longer than LGEA (p < 0.0001). The mean length of RGEA and LGEA were 26.51 ± 5.15 cm and 14.05 ± 3.12 cm, respectively. The mean area of RGEA, LGEA, and the anastomotic point were 3.31 ± 1.71 mm(2), 1.33 ± 1.01 mm(2), and 0.51 ± 0.28 mm(2) respectively. CONCLUSION RGEA was significantly longer and thicker than LGEA. The results also showed that in almost all of the cases RGEA and LGEA anastomosed with each other and grew thinner as they approached the middle of the greater curvature of the stomach.

Intracranial Bony Canal of the Middle Meningeal Artery - Morphological and Histological Analysis.

The middle meningeal artery (MMA) can play an important role in the surgical revascularization. However, the MMA can be easily injured if it passes through a bony canal. We investigated the morphological and histological features of the bony canal to improve surgical results. MATERIALS AND METHODS Fifty adult dry skulls were investigated. The length of the bony canal and the distance from the orbital rim to the bony canal were measured. Additionally, 28 cadaveric heads were examined histologically. RESULTS Sixty-three bony canals were found in 43 skulls. The mean length of bony canals was 9.2 mm, and the mean distance from the orbital rim was 24.0 mm. The bony canal ran mainly from the sphenoid bone (69.8%) to the parietal bone (73.0%). Histologically, both sides of the meningeal grooves gradually closed the distance, and formed the bony canal. The MMA inside the bony canal was enveloped with collagen tissues, divided into branches, and was accompanied by the vein. CONCLUSIONS The bony canal is located around the pterion and is formed during bone growth. The MMA is covered with collagen tissues inside the bony canal. It is possible to safely expose and preserve the MMA during craniotomy with careful drilling.

Anatomical and surgical evaluation of gastroepiploic artery

OBJECTIVE Knowledge of the anatomy of the stomach and its surrounding structures is essential for lymph node dissection. This is the first gross anatomical investigation of anastomosis variations in the gastroepiploic arteries (GEA). The aim of this study is to examine the anastomosis pattern of the right and left GEA (RGEA and LGEA, respectively). METHODS Seventeen cadavers were dissected, and the anastomotic patterns of RGEA and LGEA were observed macroscopically. RESULTS The anastomotic patterns were classified into two groups. Type 1 had direct anastomosis (n = 16; 94.1%), whereas Type 2 had no anastomosis (n = 1; 5.9%). Formation of an arterial arch along the greater curvature was observed in twelve cases (70.6%), whereas four cases (23.5%) exhibited mesh-like anastomosis or narrow anastomotic branches. CONCLUSIONS Direct anastomoses were observed in almost all the cases. These results are significant, and may be useful in the classification of lymph nodes or speculation of cancer metastases.

The impact of aging on the course of the azygos vein

INTRODUCTION The human azygos vein (AV) generally runs on the right side of the vertebral column. However, a shift in its course to the middle/left side of the vertebral column, potentially as a result of aging, has been reported. The aim of this study was to understand the relationship between AV displacement and aging. MATERIALS AND METHODS Forty-seven adult cadavers were dissected. When an AV left shift was observed, long axis AV length was measured by calculating the number of vertebral bodies under the vein. We also investigated whether a crossover vein existed between AV and hemiazygos vein at the extreme left shifting point, and whether osteophytes existed along the vertebral column. RESULTS Forty-four cadavers (94%) had left-shifted AVs. A weak positive correlation between age and the length of the left shift was observed (r = 0.3061, P = 0.0364). Thirty cadavers (64%) had crossover veins at the extreme left shifting point, and 24 cadavers (51%) had osteophytes along the vertebral column. There was no significant relationship between the length of left-shifted AVs and the existence of crossover veins or osteophytes. CONCLUSION The possibility of AV displacement to the left as part of the aging process is suggested.