Investigation has been made to develop a new method of assay for heavy metal detoxicants by utilizing the deposition pattern of heavy metal salts in the incisal dentin of rabbits. The results obtained are as follows. 1) Under a subcutaneous injection of 500 mg/kg of the lead (II) salt of Amberlite IRC-50 (Pb-A) suspended in 5% gum arabic, measurements were carried out of lead concentration in the blood in all of and its content in the urine in some of animals by the dithizone method. Single injection of this suspension brought about a continuous release of lead ions into the blood for a long period of time. The duration and amount of the release of the ions differed according to the sort of resin in the formation of the lead compound. 2) Lead ions released from Pb-A into the blood were deposited as lead salt in the incisal dentin which showed a continuous appositional growth. 3) The pattern of the deposition of lead salt in the dentin depended upon the time course of lead ion concentration in the blood. 4) The subcutaneous injection of Pb-A had almost no effect on the body weight. 5) From the foregoing results the possibilities were concluded that the assay of heavy metal detoxicants are performed without inducing the death of animals, and that, several detoxicants are assayed simultaneously with the use of one and the same animal, and moreover that, by administrating lead acetate at a certain interval, there are determined, as to the action of detoxicants, the potency, the duration and the time required for appearance.

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Investigation was made of the effects of hypophysectomy on the growth of rats, by using bone, teeth and hair. To measure the rate of growth, the lead acetate method was used for bone and tooth growth and the thallium acetate method for hair growth. The results obtained are as follow. 1) The sham-operation did not affect the bone growth of proximal tibia. But 9 days after hypophysectomy the cartilage became obviously narrow, and metaphyseal bone almost stopped growing. 2) After hypophysectomy the longitudinal growth of incisal dentin was inhibited by about 60%. Calcification was also inhibited, but one month after hypophysectomy, teeth, though extremely inhibited, still continued growing. 3) After hypophysectomy, the longitudinal growth of incisal dentin was much more inhibited than its appositional growth. The ratio, longitudinal growth/appositional growth, was smaller after operation than in control or before operation. 4) Hypophysectomy had almost no effect on the hair growth, although it showed a slight retardation in the hair eruption. The conclusion thus attained was that, under hypophysectomy, tissues differ in the rate of growth according to their embryological origin.

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This study was carried out to know the relationship between the energy expenditure and the walking mode (stride length, stride frequency) and to find out the optimum mode and speed in the grade walking at determined gradients of the slope. Experiments were carried out on four healthy adult males aged 24 years, walking or walking up on a motor-driven treadmill with aimed speeds at 35 m/min (realized values: 36.32±0.80), 45 m/min (44.65±0.51), 55 m/min (54.22 ±0.95), and 65 m/min (63.06±1.48) and gradients at 0, 5, 10, and 15 degrees. Stride lengths were 45, 50, 55, 60, and 65 cm for each combination of the speed and the gradient. In each determination of energy expenditure, the expired air was collected in a Douglas bag and analyzed by gas-chromatography. From data obtained oxygen consumption was calculated and converted into energy expenditure, and the following results were obtained. 1)Various values of energy expenditure in level or grade walking were obtained according to the variation of walking mode, though the walking speed and the slope gradient were constant. 2)A contact correlation was recognized between the ratio, stride length/ length of the leg, and the energy expenditure (cal/kg·m) under the constant walking speed and gradient. The relation may be shown in general by equations of parabola, in which the minimum energy expenditure is obtainable in the range of 0.60-0.70 of the ratio, stride length/length of the leg. 3)With the optimum speed in grade walking, the relation between the energy expenditure and the ratio, stride length/length of the leg, showed an upward concave curve with wider bottom than those with the other speeds. This fact indicates a less influence of the variation of the ratio, stride length/length of the leg, upon the energy expenditure. 4)The optimum value of stride length/ length of the leg in the grade walking at each gradient showed the maximum value at the optimum speed. 5)The optimum speed in the grade walking shifted to the slower side according to the increase of the slope gradient. 6)A contact correlation was recognized between the energy expenditure and the gradient in each grade walking speed. Energy expenditure (cal/kg·m) may approximately be presented as an exponential function of the gradient. Though all other authors discussed this problem from the viewpoint of energy expenditure under some grade walking conditions (speed, slope gradient), the present author attempted to analyze this problem from the standpoint of the optimum speed or the optimum mode of grade walking.

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The lung histamine contents of air-control and O3-, SO2-, NO2- exposed guinea pigs were compared, and the water content of the lungs was estimated in each group. It was noted that the mean histamine content of the lungs of animals exposed to low and high concentrations of ozone was below the mean of the control group. Lung edema was produced by both low and high concentrations of ozone exposure. Massive lung edema was also produced in the lungs of guinea pigs exposed to a high concentration of NO2, while there was no significant change in the mean histamine content of the lungs. Using an apparatus for perfusion of isolated lungs of guinea pigs, a large amount of histamine was found to be contained in the perfusion out-flow collected during 0 to 90 minutes from O3-ventilated lungs.

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For the purpose of studying the hormonal effect on the growth pattern of the dentofacial complex, fifteen young Wistar strain rats were given a daily dose of 0.5mg of growth hormone (NIH-GH-B-12) at 21 to 30 days of age. Roentgenographic cephalograms, which were taken every 10 clays, were analyzed by the coordinates method and linear measurement. In the normal (control) rats, the retrognathic facial pattern changed into the prognathic type at about 20 days of age due to the forward growth of the anterior part of the viscerocranium and the downward growth of the anterior part of the mandible (1967). In the experimental group, the prognathic growth pattern of the dentofacial complex was stimulated by the injections of growth hormone for 10 days. The viscerocranium showed a response to growth hormone, while the neurocranium showed the same growth pattern as that of the control group. The prominence of the nasal and gonial parts and the descent of the anterior part of the mandible were marked.

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The range of jaw movements at the incisor point was recorded and analyzed three dimensionally. It was found, as the result, that 1) the range of movements was shown as a rhomboidal figure, and the angle of Gothic arch in the horizontal plane was approximately 120 degrees from the centric occlusion to the vertical dimension of 20 mm, 2) the posterior border opening and closing pathways were present a little forward to the apex of Gothic arch, and 3) the hinge movement was impossible in few cases.

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A man aged 22 years had congenital partial anodontia. His dentition was as follows: Of these the deciduous teeth had to be removed because of caries and imminent exfoliation. His occlusion indicated prognathic position of the lower teeth, and the lower anterior teeth extended considerably above the gingival line of the upper anteriors. The cephalometric analysis revealed that the maxilla was retracted in relation to the cranium, while the mandible was protracted. In the functional analysis, the freeway space was 10.2mm, and at the physiological rest position the mandible swung downward and backward to approach the edge-to-edge bite. Initially, in order to correct the acute prognathic relation two kinds of bite planes were worn by the patient for a year and a half to increase the vertical dimension by 8mm. The permanent restorations were constructed at the established vertical position. The maxillary reconstruction was completed utilizing splinted full gold cast crowns on the molars, splinted bounded porcelain veneer crowns on the incisors and a removable partial denture replacing the absent teeth. The mandibular rehabilitation was accomplished utilizing splinted full gold cast crowns on the molars as well as a fixed partial denture that extended from the right second premolar to the left. After treatment, the anteroposterior relationship of the maxillary and mandibular teeth has been corrected, and with a concave face the position with respect to the cranium is not necessarily abnormal for the maxillomandibular base bone.

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The responses of the whole glossopharyngeal nerve of the toad to inorganic and organic acids were markedly enhanced by the addition of univalent chloride and calcium chloride. The ratios of response of mixtures to the sum of respective responses of M/512 acids and M/4 chlorides were 1.2-2.7. The facilitatory effect of sodium chloride on responses to M/512 hydrochloric acid and acetic acid was observed in concentration of M/16 and the facilitation appeared in the concentration of the salt.

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An attempt was made to study the role of the cartilaginous nasal septum in the growth of the upper face, which is related to one of the most important problems in orthodontics. The cartilaginous nasal septum of 25 growing rats was resected with an electric knife at 20 days of age. The control group consisted of nine rats. Measurements were taken on the serial roentgenographic cephalograms and dry skulls of both groups were prepared. Findings were as follows: l. The nasal, frontal, premaxillary and maxillary bones of the experimental group were shorter than those of the control, especially in the anteroposterior dimension. The width at the orbital and frontomaxillary regions was broader in the experimental group. 2. In the experimental group, the growth in the anterior part of the upper face (the orbital, nasal, alveolar and incisal parts) was dominantly inhibited and the change in the growth direction was downward, showing a downward deflection of the snout. 3. The mandible shifted backward and downward, caused by the change in the maxillary growth direction. A slight mesiocclusion of the molars was observed in the experimental group.

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