Anatomical features (shape, weight and myofibrous composition) of skeletal muscles reflect the muscular functions. In this study, we histologically analyzed the myofibrous composition of corresponding muscles and compared their functions in man and the macaque. Among the intrinsic hand and foot muscles, the hand muscles for gripping and pinching movements were well developed in humans and those for hanging were well developed in the hands and feet of the macaque. Of the spinohumeral muscles, morphological differences (thickness of muscle layer and muscle fiber size) were observed in different regions. In the muscles in the upper and lower extremities, the relative weight and myofibrous composition were correlated with the characteristics of their respective motions. There were differences in myofibrous composition among those muscle groups due to bipedal or quadrupedal walking by man and the macaque. The differences in the myofibrous composition of the muscles for vocalization (laryngeal muscles), and the innervation ratios of the muscle fibers reflected vocal ability.

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A photographic technique was used to measure the angle between the longitudinal axis of the ear and the bridge of the nose of 619 young adult Thai women, aged 15 to 25 years, from all 6 regions of Thailand, and that of beautiful Thai women subjects to determine the most desireable angle. This was done to test the validity of the hypothesis which postulates that the longitudinal axis of the ear should be parallel to the bridge of the nose, and to compare this angle with those determined from studies in other countries to determine national differences. It was also desired to determine the angle that looks best and appears to be most aesthetically pleasing from evaluation of questionnaires. It was found that the longitudinal axis of the ear is not parallel to the bridge of the nose and that the angle in Thai women should be 19.3±5.5 degrees to provide both proper and aesthetic placement of the reconstructed ear. There is no statistically significant difference in this angle among the populations of all regions of Thailand and the beautiful women subjects. However, Thais, Japanese and Americans have different angles, so it appears that each nationality has its own normal value for this angle.

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Characteristics of the rhythm-generating neural network model proposed by Amari (Proc IEEE 59: 1971) are analyzed and interpreted as the respiratory center. It is a mathematical model consisting of two networks that project to each other. One network contains a large number of excitatory mathematical neurons which connect randomly, and the other contains inhibitory neurons. The proportion of mathematical neurons that will fire has been shown to oscillate in the presence of tonic excitatory inputs from the environment. It has been demonstrated by physiological experiments that excitatory and inhibitory respiratory neurons are distributed in the caudal and rostral medulla, respectively. By assuming that the caudal excitatory respiratory neuorns connect to the rostral inhibitory respiratory neurons, this model can be applied to the respiratory neurons in the medulla, although such connections are not yet proved. However, long period oscillations, which correspond to respiratory rhythm, can be obtained over limited ranges in the wide area of parameters in which oscillations can occur. Therefore, other mechanisms at the neural network level and/or the individual neuron level must also contribute to respiratory rhythmogenesis, even if this assumption is established.

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The structural and functional properties of molar periodontal ligament (PDL) fibroblasts from aged rats (12 to 18 months old) were investigated by light and electron microscopic morphometry, enzyme cytochemistry and autoradiography. The PDL fibroblasts of aged rats were extremely flattened and irregular in cell profile. Most of these cells were also devoid of the cytoplasmic organelles involved in protein synthesis. However, they did have phagolysosomes, containing intact collagen fibers, in which intense acid trimeta-phosphatase activity was detected. Characteristically, multinucleated fibroblastic cells (MFC) were frequently found throughout the ligament. These MFCs also contained many phagosomes, but as was demonstrated by autoradiography of ³H-proline, some MFCs still had the capacity for procollagen synthesis and secretion. In general, these mononuclear PDL fibroblasts and MFCs contained few procollagen secretion granules and had very weak or no alkaline phosphatase activity. In contrast, this enzymatic activity was intense in the PDL fibroblasts of young rats. Although phagocytosis of collagen fibers in the matrix was especially prominent in MFCs at the site of osteoclastic bone resorption, it also occurred in most fibroblasts throughout the ligament. This resulted in the presence of pericellular matrix-free spaces, which were much wider than those in young rats. These results suggest that PDL fibroblast metabolic activities, such as reduced procollagen synthesis and increased phagocytic activity of collagen fibers in the matrix, are unbalanced in aged animals.

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A method of enzyme-linked immunosorbent assay (ELISA) for measuring primary bile acid (cholic acid: CA) and secondary bile acid (deoxycholic acid: DCA) excreted in human feces has been developed. By this method, bile acids were measured in feces of healthy individuals and colon cancer patients, and the DCA/CA ratios were calculated from the measured values. We then evaluated the clinical applicability of this method. The study clearly demonstrated a significant difference between normal subjects and colon cancer patients. The DCA/CA ratios of pre-operative colon cancer patients were higher than those of healthy subjects, but post-operatively the ratio approximated the level of healthy subjects in every case. The mechanism in which fecal bile acids promote the pathogenesis of colon cancer is not well understood, but the fecal DCA/CA ratio can be usefully applied to the diagnosis of colon cancer and to screening those at high risk. Similarly, if this test is used as a prognostic marker, it is possible to recommend improved dietary habits for the high-risk individual. Hence, the test should become an effective preventive measure against colon cancer.

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The serotonergic Innervation of neurons containing vasopressin (VP) was examined by electron microscopy using a method of pre-embedding peroxidase-antiperoxidase (PAP) to show serotonin with post-embedding immunocolloidal gold staining (IGS) to show VP in the same tissue sections. Serotonin-like immunoreactive (serotonin-LI) terminals were found to make direct contact with VP-like immunoreactive (VP-LI) neurons at the light microscopic level. Ultrastructural observation revealed that serotonin-LI axon terminals, containing immunoreactive granular vesicles (70-80 nm in diameter), formed synapses with magnocellular neurosecretory neurons in the supraoptic nucleus (SON) and the paraventricular nucleus (PVN) . In the combined PAG-IGS preparations, PAP-labeled serotonergic axon terminals appeared at times making synaptic contacts with IGS-labeled VP-LI cell bodies and dendritic processes. These findings provide morphological evidence of direct synaptic influence of serotonergic elements on the secretory activity of VP-containing neurons in the rat hypothalamic SON and PVN.

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Intraperitoneally applied ACTH produced either hyperalgesia or analgesia depending upon dose; 60 μg/kg ACTH produced hyperalgesia, and 250 μg/kg ACTH produced analgesia. Analgesia was abolished by hypophy-sectomy or mesencephalic lesion leaving the hyperalgesia unchanged. Maximum hyperalgesia was produced by 0.6 μg/rat intrathecal ACTH. The maximum was reached in 30 minutes, and then reduced to the control level 75 minutes after application. The effect was competitively antagonized by intraperitoneal 0.6 mg/kg dexamethasone. It was strongly suggested that hyperalgesia might be produced by activation of ACTH sensitive sites in the spinal cord, and analgesia might be produced by such sites at the supraspinal level.

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The effects of fibrous hydroxyapatite on the process of bone formation was studied in histological and biomechanical animal experiments. First, fibrous hydroxyapatite was implanted in a hole made in the midfemur of a white rabbit. Second, after midf emoral transverse osteotomies were performed on mongrel canines, fibrous hydroxyapatite was implanted in the osteotomized site, and then fixed with a dynamic axial fixation system. At 3 weeks after osteotomy, axial dynamization, histological observations, and bone histomorphometric analysis were performed in some animals. Third, after a window was made in the lateral midfemur of a canine, fibrous hydroxyapatite was implanted, and a three-point bending test was performed. In the hydroxyapatite group, osteoprogenitor cells gathered soon after surgery showing active osteoid hyperplasia. Trabecular bone specific volume (tVsp) and fractional formation surface (FrFS) remained higher throughout the entire process. In the dynamization group, features of mature bone accompanied by a decrease in the number of osteoids were evident in the early stage. In a three-point bending test, the stiffness and maximum load increased sharply, particularly after 4 weeks. These findings suggest that, in the process of bone formation, fibrous hydroxyapatite acts as an osteoconduction material, which accelerates bone maturation under the influence of axial dynamization. It also provides mechanical stability from an early stage.
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Endogenous hydrogen peroxide (H₂O₂), which is generated invariably in normal cells, serves as a precursor for highly reactive oxygen intermediates. Although cellular function is equipped with an effective defense mechanism against the action of H₂O₂, the activity of the defense mechanism has been reported to decrease during Ischemia-reperfusion. Though H₂O₂ is cataiytically reduced to H₂O by either catalase or glutathione peroxidase, the amount of catalase activity in the heart tissue is much lower than in another organs and its role is still uncertain. In the present study we investigated the role of catalase as a defense mechanism against reperfusion injury. Catalase was inhibited by intraperitoneal injection of 3-amino-1, 2, 4-triazole (ATZ) 30 min before the excision of the rat heart. After 20 min of reperfusion following 10 min of global Ischemia, the sarcoplasmic reticulum (SR) was extracted by centrifuga-tion. We found that ATZ treatment significantly affected recovery of the contractile function during reperfusion. Ca²⁺-ATPase activity and the content of the major ATPase protein of the SR after reperfusion were significantly decreased by ATZ, indicating degradation of the SR. The results indicate that catalase is an important cellular defense mechanism that alleviates the toxic effect of endogenous H₂O₂ in the myocardium during ischemia-reperfusion.

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Aneurysm of the splenic artery was thought to be an infrequent lesion in Japan, however with the availability of CT examination the number of reports of this lesion has increased. We report here, a splenic artery aneurysm with gastric carcinoma. A 64-year-old woman with epigastralgia and nausea was admitted for surgical treatment of gastric carcinoma. During the pre-operative examination, abdominal plain X-ray showed a small rounded calcifica-tion in the left upper quadrant, endoscopic examination indicated a small elevated lesion-like submucosal tumor on the posterior wall of the upper gastric body, and CT scan showed a round 2 cm calcification of the splenic hilus as a splenic artery aneurysm. Total gastrectomy with splenectomy was performed. On the resected specimen, a hard calcified round mass of the splenic hilus was detected as, coexisting gastric carcinoma. Microscopically, a section from the aneurysmal firm nodule had an extensively dilated hyalinized thickened arterial wall with fibrosis. The clinical circumstance of the calcification as revealed by plain X-ray, the typical finding of the CT scan, and the elevated lesion-like submucosal tumor of the stomach added special interest to the diagnosis of splenic artery aneurysm.

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