It is commonly known that a certain amount of blood flow is required in the dental pulp to keep the teeth healthy. The amount of the blood flow in the dental pulp is an important factor in the growth of the jaw and teeth. The author studied the changes in the blood flow in dental pulp by applying the dentist's ordinary drugs, alcohol and cigarettes, which often directly touch the dental pulp when it is exposed. The untreated teeth opposite the treated ones were examined for comparison. The follwing results were obtained:
1. Application of disinfectants such as Oxydol, Neocleaner and Rusnon caused a momentary decrease in the blood flow which lasted about twenty to thirty minutes before the flow was restored.
2. Xylocaine, a local anaesthetic, caused a slight increase or a strong momentary decrease in the blood flow. When epinephrine was added to Xylocaine, the effect became apparent, that is, the blood flow clearly decreased.
3. Calvital, a drug made of calcium hydroxide, and a solution of calcium hydroxide, both of which are used as preservatives for teeth, caused a strong momentary or lasting decrease in the blood flow. In cases where the effect lasted, the flow was not restored for more than three hours after the treatment. Two weeks afterwards, however, the blood flow was definitely greater than it had been before the application of these drugs.
4. Acidulated fluoride solution, used for preventing dental caries, definitely decreased the blood flow on the treated side.
5. Liquid detifrice, used as a dental hygienic drug, induced a momentary increase or decrease or no change in the blood flow. The color tester, plaque disclosing solution, had almost no effect on the blood flow.
6. A solution of 20% Etyl alcohol caused a slight a momentary increase or a distinct momentary decrease in the blood flow. Aqueous extract solution of cigarettes brought about a very slight momentary increase or decrease in the blood flow.

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In a previous study, the author confirmed the preservative effect of Calvital through the observation of the blood flow in the dental pulp. In this study, the action of Vitapex (V. drug, hydroxide to which iodoform is added), a root canal filling material which is similar to Calvital, is examined. Dentists usually use V. drug after pulling out the dental pulp in order to plug the cavity. For the purpose of studying the effectiveness of the preservative effect of V. drug, the author measured the blood flow in the dental pulp of the canine teeth of dogs in vivo by the hydrogen gas clearance method after making a small canal reaching the pulp cavity and plugging it with V. drug. The measurement was carried out for thirty weeks at two week intervals.
1. The blood flow is measurable for a long term relative to control, from 14 weeks to 30 weeks or more even in the exposed dental pulp when the pulp has been treated with V. drug. In 10 of 14 cases of untreated canine teeth it was possible to measure the blood flow in dental pulp for from two to four weeks. In three of the remaining four cases the respective periods of measurement were 6 weeks, 22 weeks and 28 weeks. In the final case, the blood flow was measurable for more than 28 weeks.
2. The dental pulp where measurable blood flow is observed owing to the V. drug treatment clearly shows in the field of the microscope the tissues maintaining their functions, that is, the author can clearly distinguish that it is vital pulp. In contrast, the tissue of the dental pulp which has no measurable blood flood does not maintain the form of tissue and it can be definitely determined that the dental pulp is dead.
3. It is important for maintaining the normal function of dental pulp to keep a certain amount of blood flow volume. It is considered that V. drug is effective in maintaining this flow in the vital pulp.
4. It is clearly recognizable that blood flow is histologically maintained in the examined pulp which has blood flow measurable by the hydrogen gas clearancee method. If blood flow in the dental pulp is unmeasurable by this method, the blood vessels in the dental pulp can't be recognized histologically. It is apparent from this agreement that the hydrogen gas clearance method is useful for observing the movement of the local blood flow.

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悪性新生物と共に死亡率の高い脳血管・虚血性心疾患および高血圧性疾患の46都道府県別の性・年齢階級別死亡率を目的変数とし社会生活統計指標(20指標)を説明変数とする重回帰分析(逐次変数選択法)を5年間隔で2回(1970,75年)実施した。これらの説明変数は以前の我々の解析(因子分析)により8群の地域生態学的因子に分類されている。
以下の3因子が2年次とも特定の性・年齢階級別の各疾患の死亡率(カッコ内)に有意な正の影響を与えたファクターとして抽出された。1)地方居住(中高年男女および若年男子の脳血管疾患と中年男女の虚血性心疾患)。2)低所得(高年男女と中年女子の高血圧性疾患)。3)都市居住(中年男子の脳血管疾患)。逆に,高齢人口と高年男女の虚血性心疾患および中年男子の脳血管疾患との負の関係が推定された。
これら3疾患の性・年齢階級別の死亡率は高年女子の虚血性心疾患でのみ5年間に有意な上昇がみられた。

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The thermal diffusion method is based on a linear relationship between thermal conductivity of tissue and the tissue blood flow. Therefore, thermal diffusion is very sensitive to changes in tissue blood flow. However, it has been impossible to assess tissue blood flow quantitatively by this method. For the quantitative dynamic assessment of body surface circulation, a thermal diffusion flow probe incorporating a Peltier stack was used. In order to modify the apparatus using this probe for measuring body surface circulation continuously, fundamental studies about the measurement of human skin blood flow were carried out in the finger using the thermal diffusion method. The results obtained were as follow.
1) The voltage difference of the thermocouples (V) of a probe placed on plates of various materials similar in the thermal conductivity to human skin was measured. A highly positive correlation between the thermal conductivity of the material and the reciprocal number of the voltage difference of the thermocouples (1/V) (r=0.973, p<0.001) could be observed. The use of this probe enabled us to assess the thermal conductivity of materials and tissues quantitatively.
2) V gradually increased in parallel with the finger ischemia induced by inflation of a touniquet, suggesting that V varied with the change of finger blood flow and that its baseline was steady.
3) A highly significant positive correlation was obtained between finger blood flow measured by the inhaled hydrogen clearance method (Hydrogen_i FBF) and 1/V (r=0.949, p<0.001). V with no flow (V₀) and constant Φ was estimated, and a calibrating line based on the following equation was determined.
F=Φ(1/V-1/V₀)
Finger blood flow measured by the thermal diffusion method (Thermal FBF) was obtained. A highly significant positive correlation was obtained between Hydrogen_i FBF and Thermal FBF (r=0.949, p<0.001).
4) A highly significant positive correlation was obtained between finger blood flow measured by an electrochemically generated hydrogen clearance method (Hydrogen_e FBF) and 1/V (r=0.953, p<0.001). Calibration by this method was carried out taking account of the apparent flow by diffusion of hydrogen gas to the surrounding area (Diffusion Flow). A highly significant positive correlation was obtained between Hydrogen_e FBF subtracted Diffusion Flow and Thermal FBF (r=0.953, p<0.001).
5) Thermal FBF calibrated by the electrochemically generated hydrogen clearance method almost agreed with that determined by the inhaled hydrogen clearance method in terms of the absolute value of the finger blood flow.
Using the thermal diffusion method calibrated previously by the hydrogen clearance method in normal human subjects, the absolute value of skin blood flow can be measured continuously and noninvasively in humans. It was concluded that the apparatus for measuring skin blood flow continuously by the thermal diffusion method could be utilized as a monitor of the body surface circulation and was thus useful for diagnosis and research in various medical fields.

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The present study aimed to clarify the mechanism and conditions for carcinogenic N-nitrosopyrrolidine (NPYR) formation in bacon during the cooking process, analyzing the precursors of N-nitrosamines in various materials, including raw pork and spices. Results obtained are summarized as follows:
1. When bacon samples were brought to 100°-200°C within 10 minutes, the amounts of NPYR formed from free proline via pyrrolidine (Pyr) were almost the same levels as those formed via N-nitrosoproline (NPRO). In contrast, when samples were heated at 225°C, the yield of NPYR via Pyr was apparently greater than that formed via NPRO.
2. Concerning the precursors of N-nitrosamines in fresh pork samples, spermine, a polyamine, was found to range from 50-100mg/kg, while levels of other polyamines were less than 1/10 of the spermine level.
3. With regard to the precursors of nitrosamines in spices used for preparing commercial bacon, it was found that only pepper contained such compounds among the various spices so far tested, viz., pyrroperine and Pyr were detected, and both compounds are precursors of NPYR. In addition, piperine and piperidine which form N-nitrosopiperidine after a nitrosation reaction were isolated. The rates of nitrosation of the aforementioned compounds under acidic conditions at 37°C and 100°C were also studied.

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The Blackpool table was used in Hong Kong subway construction work where we did medical consultation on how to prevent decompression sickness. Between 1975 and 1984 there were 260 bends patients out of 28, 554 workers who were exposed to pressures of between 1.2 and 2.8kg/cm², and the incidence of decompression sickness (bends) was 0.91%. This percentage of bends is considered quite acceptable.
The Blackpool table has been recognized as one of the safest decompression schedules experimentally but it became clear that its schedule for the prevention of decompression sickness could be improved upon through observation and evaluation by a bubble counting technique using an agarose gel model.
The Model One table, which was developed by us, was applied to the Blackpool table to decrease the incidence of bends. These two decompression schedules were checked by a bubble counting technique. The special feature of the Model One table is that it utilizes the initial decompression ratio between the bottom pressure and the first stop of decompression; i. e., the slow decompression ratio of 0.1kg/cm²/min, in contrast with the Blackpool table.
The extension of the total decompression time is less in Model One than in the Blackpool schedule, however, the number of bubbles formed in the agarose gel model decreased significantly and the incidence of bends was also decreased by nearly one half.
This demonstrates that the initial decompression ratio is another key for decreasing the incidence of bends.

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Decompression sickness (bends) is generally considered to be due to the effects of bubbles which originate from supersaturated gas dissolved in the blood and other tissues.
The bubbles in the tissues are formed from pre-exisiting gas nuclei. The gas initially diffused into the gas nuclei in the tissue and is then forced out by decompression, depending on the difference between the inside tension of the gas nuclei and the surrounding tension of the tissue.
Mammalian gelatin samples were first used according to this theory by LeMessurier in 1972 as a model in the etiology of bends, and further careful research has been carried out by Beckman, Yount, Mano and their co-workers. Mano et al. have evaluated the relative effectiveness of standard decompression tables in reducing bubble formation using the agarose gel bubble technique under rigorously controlled conditions.
Bubble formation is mainly due to the decompression ratio, accompanied by hyperbaric exposure; however, the variation of exposure temperatures also influences the formed bubbles even though there are no decompression steps.
Therefore, to understand the relation between the temperature and bubble formation, research was undertaken. This bubble work is composed of two groups of experiments. One involved saturation experiments, and the relation between the number of bubbles and different saturation pressures was obtained as a regression line. The temperature was controlled at 20.0±1.0°C.
In the other experiments, the environmental temperature was changed between 5 and 30°C. Agarose gel samples, with 15 cells in a set, were exposed to the same bottom pressure but the environmental temperature was varied in each set of conditions.
The number of bubbles was counted in each sample and the cells were heated to 30°C for 30min and bubble counting was then done. The exposure time at the bottom pressure was 30, 60, or 120min in the non-saturation experiments and 6 hours in the saturation experiments. The phenomena of bubble formation according to the variations of the temperature were investigated in detail, and, eventually, significant regression equations could be obtained with good relations in all defferent conditions of hyperbaric exposure.
This result gives us much information on bubble formation phenomena, which can aid us in carrying out our basic research on decompression sickness, especially as concerns the influence of environmenal temperature, although there are differences between in vitro and in vivo phenomena. Moreover, the standard decompression table by the Ministry of Labour could be evaluated by this bubble counting technique. The safety of the table was questionable, and it was recognized that the table was not necessarily correct. This research will be applied to various fields of diving or compressed air work in the future.

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病院からの廃水処理を指向して,表面改質活性炭(含窒素活性炭,低温酸素プラズマ照射処理活性炭)を調整し,消毒薬成分であるフェノールおよびクレゾールの吸着除去実験を試みた。
活性炭に対するフェノールおよびクレゾール吸着量と吸着剤の細孔構造との間には有意な相関関係は認められなかった。吸着量の差は,活性炭表面の荷電状態と吸着質のフェノール性アニオンとの相互作用に起因することが示唆された。
吸着速度に関して,表面改質活性炭へのフェノールおよびクレゾールの粒内拡散係数は,各吸着率において,原活性炭に対するよりも大きな値を示した。含窒素活性炭およびプラズマ照射処理活性炭において大きな粒内拡散係数を示した理由は,それぞれ吸着質であるフェノールおよびクレゾールと吸着剤表面の荷電状態との相互作用,プラズマ照射処理による活性炭のトランジショナル孔容積が増大したことに基づくものであると考えられる。
病院からの廃水を処理する際,含窒素活性炭が至適であることが判明した。

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In mouse spleen cells, the effects of chloroplatinic acid and zirconium oxychloride on IgM antibody production against sheep red blood cells (SRBC) were studied in vitro. The following conclusion were drawn from this study:
1. Chloroplatinic acid suppressed direct plaque formation against SRBC in mouse spleen cells in vitro.
2. The viability of mouse spleen cells, to which chloroplatinic acid was added was higher than that of control when they were cultuerd in a CO₂ incubator for 4 days.
3. Zirconium oxychloride enhanced direct plaque formation against SRBC in mouse spleen cells in vitro.
4. Direct plaque formation in mouse spleen cells blended with macrophages obtained from mice intraperitoneally injected with zirconium oxychloride for a week showed a larger increase in response than when there was no addition of Zr-sensitized macrophages.
From these results, it is suggested that the suppressed IgM immune response resulting from the addition of chloroplatinic acid may due to activated suppressor T cells, and that the enhanced response brought about by adding zirconium oxychloride may depend upon activated macrophages.

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本報は青年期女子の脂肪と体実質との身体組成の正確な判定方法究明を目的としたものである。身体組成の判定指標としての人体比重は,この研究分野では絶対的コンセンサスが得られている。本研究では人体比重を女子大学生81人を対象として水泳プール利用した水中体重測定法により計測した。しかし,人体比重測定は水中体重測定,残気量測定という複雑な手順と手技に加えて特殊な機器が必要であるため,簡便に測定できる身体諸計測値からより正確に人体比重を推定するための予測式を作成した。方法としては,実測された人体比重を従属変数とし,同時に並行して測定した身長,体重,周囲径,皮厚ならびに年齢と運動歴を独立変数として重回帰分析と因子分析を行った。得られた主なる所見は以下のようである。
1.本測定法によって得た対象集団の人体比重の平均値と標準偏差は,1.0480±0.0126(X±S.D.)である。これは,同年齢者を対象とした既報文献成績と比較して若干高値である。しかしながら,本報の非運動群(N=23)のみの対象者の成績では,1.0433±0.0120と既報文献と同様な成績である。すなわち,全体としての平均値を高値にしているのは現運動群(N=19)の1.0569±0.0126および,旧運動群(N=39)の1.0465±0.0113の影響のためである。
2.年齢,運動歴,身長,体重,上腕囲,胸囲,腹囲,腰囲,大腿囲,上腕部皮厚,肩甲骨下部皮厚,側腹部皮厚,大腿前中部皮厚および人体比重を変数とした因子分析により4個の因子(累積説明率は77.7%)が得られた。第1因子は体重と周囲径すなわち身体の幅厚,第2因子は全身の脂肪量,第3因子は躯幹の皮下脂肪量,第4因子は身長に関する因子と解釈された。人体比重は第2因子に含まれていた。運動歴を除いての同様な分析では3個の因子が得られた。3個の因子による累積説明率は67.3%である。第1因子は体型,第2因子は体脂肪量,第3因子は体格に関する因子と解釈された。人体比重は第2因子に含まれていた。
3.人体比重を従属変数とした重回帰分析により,第1編入説明変数は上腕部皮厚,第2編入説明変数は運動歴,第3編入説明変数以下は側腹部皮厚,大腿前中部皮厚,身長,肩甲骨下部皮厚,体重,腹囲,胸囲,腰囲,上腕囲,年齢の順序であった。
4.スクリーニングなど現場で利用する場合の人体比重予測式としては,運動歴が明確に判別できる場合Yc=1.062221-0.001166・X₁+0.005512・X₂〔X₁:上腕部皮厚,X₂:運動歴(現;2,旧;1,非;0)〕R=0.619(p<0.001)が得られた。また,運動歴が明確に判別できない場合Yc=0.994044-0.000979・X₁-0.000755・X₂+0.000693・X₃〔X₁:上腕部皮厚,X₂:体重,X₃:身長〕R=0.590(p<0.001)が得られた。なお,この予測式は既報文献のものと比べて相関係数では高値とは言えない。しかしながら,人体比重予測式は身体組成の体実質と体脂肪のそれぞれの因子に関連する変数を使用すること,ならびに,使用する測定項目は上腕部皮厚と運動歴(現,旧,非),または,身長と体重と上腕部皮厚であり,容易に測定ないし聴取できるため実際面での簡便さにおいても優れている。

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