Ryoichi Mori

Comparative Histology of the Laminar Bone between Young Calves and Foals

Laminar bone or primary plexiform tissue, not Haversian bone, shows an alternative concentric pattern of laminar-bone units or plates around the bone marrow periphery of long bones, although the laminar bone is gradually replaced by osteons during the growth period. One laminar-bone unit is constructed with a hypercalcified line in the center, woven bone on both sides of the line, and lamellar bone with laminated appositional lines. Such a laminar bone showing a homogeneous calcification has been reported in young calves and some young large animals, but it has not been reported in foals although a previous report proposed that the bone structure was distinguishable from plexiform tissue. In this study, we compared young calves with foals by backscattered electron imaging mainly of transverse ground sections of mid-diaphysis. Foals had many hypercalcified lines arranged concentrically around the bone marrow periphery, which were similar to those of young calves. However, rows of cylindrical osteon-like structures with Haversian canal-like canals running along the long-bone axis were arranged between the concentric hypercalcified lines. Each Haversian canal-like structure was enclosed with laminated appositional rings of lamellar bone deposited on the woven bone. In the developing period, the bone units containing the concentric hypercalcified lines were basically equal to the laminar-bone units. The osteon-like structures or ‘pseudo-osteons’ were gradually replaced by ‘true osteons’ during the growth period. The blood vessels in the Haversian canal-like canals of foals ran along the long-bone axis, whereas the blood vessels in the concentrically prolonged bone cavities of young calves ran transversely to obliquely against the long-bone axis. Thus, the long-bone cortex of foals showing an alternative concentric pattern of a row of the osteon-like structures arranged between the hypercalcified lines will be histologically classified into a variety of laminar bone caused by the different arrangement of blood vessels. Such a laminar bone may have a biomechanical structure against physical stress, especially the modified laminar bone of foals with osteon-like structures, when compared with the typical concentric laminar bone of young calves and also Haversian bone possessing variously calcified numerous osteons caused by bone remodeling.

Structural and analytical comparison of gallbladder stones collected from a single patient : studies of five cases

We observed the gross and fine structure of gallbladder stones collected from five adult patients (cases I–V) by optical photography, radiography, scanning electron microscopy, and backscattered electron microscopy, and then measured the components by energy-dispersive X-ray microanalysis and infrared spectroscopy. From the stones, calcium (Ca) phosphate, Ca bilirubinate, and Ca palmitate or fatty acid Ca were identified. The 3 cholesterol stones (case I) and the 2 brown pigment stones (case II) showed macroscopic homogeneity, respectively. In addition, their fine structure and components were also similar to each other. The black pigment stones (case III) showed macroscopic homogeneity, but they were divided into radiopaque (∼30 stones) and radiolucent types (∼60 stones). The former had Ca phosphate in the center surrounded with Ca bilirubinate, and the latter was dotted with minute deposits of Ca bilirubinate. The 6 cholesterol stones (case IV) were divided into two types in size. The 5 large stones, of macroscopic homogeneity, had a core region of Ca palmitate and clear concentric rings of Ca phosphate, whereas the smaller stone was almost filled with Ca phosphate deposits in the center. From the different distributions of Ca phosphate, the smaller stone may have been formed later than the 5 large stones. Case V contained 4 stones. The 3 large cholesterol stones, of more or less macroscopic homogeneity, had a core region and concentric rings of Ca phosphate, but 1 smaller stone was dotted with minute deposits mainly containing iron (Fe) and/or silicon elements (rare type). Therefore, the stones of cases III, IV, and V showed considerable heterogeneity, respectively. In many stones, the initial precipitation of Ca salts will have become the nidus, and the concentric rings and dotted deposits of Ca salts may have accelerated cholesterol stone growth. In addition, the dotted deposits of Ca bilirubinate in the black pigment stones and the dotted deposits containing Fe in the rare stone may have become also the nidi.

Fine structure and mineral components of fibrous stonelike masses obtained from the human mesenteries.

We investigated the fine structure and mineral components of 29 stonelike masses obtained from the mesenteries of four adult cadavers, using optical microscopy, backscattered electron imaging, scanning electron microscopy, energy-dispersive X-ray microanalysis, and X-ray diffraction. Although the overall appearance of the stonelike masses measuring about 5–20 mm in diameter and 0.06–3.1 g in dry weight was roughly grouped into smooth bulb- and uneven bulk-shaped types, all the calcified masses basically consisted of core and mantle regions. The smooth bulb-shaped masses had a broad mantle with many concentric rings, whereas the uneven bulk-shaped masses contained a large core. In their core regions, spherulitic and short bundle-shaped deposits composed of needle-shaped apatite crystals were mainly found among loose collagen fibers. Their mantle regions, on the other hand, showed the concentric structures of dense collagen fibers in the intra- and/or extrafibrous calcification with fine sandy grain-shaped deposits. The mineral elements were mainly Ca and P, and the major crystals were hydroxyapatite. Hexahedral whitlockite containing Mg was a minor component. The fiber-rich mantle regions showed lower calcification and lesser crystallization than the fiber-poor core region. When necrotic or some tumor adipose tissues and necrotic lymphoid tissues that might have been caused by some digestive diseases are recognized as foreign matter, their tissues occasionally will be calcified and grow into stonelike masses. These stonelike masses tend to occur more often in women than in men.

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.