A prototype system of automated reticulocyte counting has been developed. The count is performed on a separated slide on which cells are stained supravitally in the new methylene blue solution. The reticulocyte counting system consists of an optical microscope with high-speed stage, stage controller, autofocusing unit, image input unit with color TV camera, A/D converter, special purpose image processor and a minicomputer. It is important in reticulocyte counting that the number of reticulocyte be few, and, therefore, that no normal red blood cells be erroneously taken as reticulocytes. For reticulocyte detection, we found some useful and simple feature parameters of substantia granulofilamentosa of reticulocyte. Experiments yielded good results using 11 sample slides including about 2 000 red blood cells consisting of normal red blood cells, reticulocytes, cells with defect and other cells. Discriminating rate of normal red blood cells has been better than 99. 9%, and discriminating rate of reticulocytes has been better than 90%. This system performs not only reticulocyte counting but also Heilmeyer's classification of reticulocytes.

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The transition process from the resting state to the state of spontaneous repetitive firing, in squid giant axons has numerically been analysed by the use of modified Hodgkin-Huxley equations. The experimentally observed behavior of the membrane potentials in this process was well simulated by the numerical solutions of the modified Hodgkin-Huxley equations.
It has been concluded by this analysis that the resting state and the state of spontaneous repetitive firing in squid giant axons correspond thermodynamically to a thermodynamical branch and a dissipative structure in the non-equilibrium system and mathematically to an equilibrium point and a limit cycle in the nonlinear system.

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A rapid and automated method for detecting bacteria is described. This method stands on simultaneous measurement of the changes in electrical impedance and turbidity of culture medium. The system is composed of the culture cell, detecting electrical circuit, A/D converter and microcomputer. The impedance change is measured by means of four-electrode technique and the turbidity change-is monitored using a pair of light emission diodes (LED) and CdS photo-conductive elements. The differential curves (the rate curves), which show the characteristic patterns specifying each type of bacteria and good reproducibility, are computed from the changes of impedance and turbidity. The standard differential patterns (the standard rate patterns) are calculated for each type of bacteria by averaging the rate curves several times. Identification is carried out by comparing the rate curves of unknown bacteria with the standard rate patterns. 102 samples of ten bacteria species (coliform bacteria) have been tested. 101 samples (99 percent) have been identified within 2-5 hours. 100 percent of test samples have been correctly identified within 5-8 hours. This experimental apparatus is rather simple compared with other automatic systems, such as the light scattering system or the radiometric method, and this method can be made available in biological routine test.

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It was well known that there was good correlation between the cardiac output (CO) calculated by impedance plethysmography (IMP) and CO measured by other methods such as Fick's method and dye dilution method, but CO calculated by the former method including pulmonary circulation has proved larger than that measured by the latter method.
This study is aimed at recording IMP more easily to save aluminized tape electrodes and to avoid overestimating CO by IMP.
After measuring CO by IMP utilizing 4 aluminized tapes surrounding the thorax, the 4 tapes were cut at bilateral axillary lines and CO contents were measured by 4 kinds of half-taped methods : both upper halves at the neck and abdomen (Up-Up), both lower halves at the neck and the abdomen (Down-Down), upper half at the neck and lower half at the abdomen (Up-Down) and lower half at the neck and upper half at the abdomen (Down-Up).
CO volumes calculated in 22 patients by Up-Down method were correlated best (r=0.89), among the 4 kinds of half-taped methods, with Kubicek's method and they had the best equality (y=-0.02+1.03x). In 14 patients without shunt and regurgitant heart diseases, CO volumes were measured simultaneously both by Up-Down half-taped method and by Fick's method. The results were correlated well (r=0.91) but CO by Up-Down half-taped method was smaller than by Fick's method (y=0.11+1.39x), as some of subjects (60±11 years old) had pulmonary emphy-seme and increased the transthoracic impedance Z₀ (Z₀=31+5Ω).
From this study, it has been concluded that IMP using an Up-Down half-taped method could be recorded more easily than the usual method as there was a harmless influence of female breasts and long cut hair and that CO by this convenient half-taped method was correlated well not only with CO by IMP according to Kubicek's method but also with CO obtained from Fick's method. These conclusions showed usefulness of this convenient half-taped method of IMP.

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The four-electrode method has many advantages in monitoring the impedance change in the solution of growing bacteria. To examine the reason for good reproducibility, the characteristics of impedance change are measured by changing the material of metal electrodes, the length between electrodes, source frequency and amplitude of applied constant current, as well as the magnitude of the series resistance R₀. The R₀ is inserted to obtain constant amplitude of current. The results are summarized as follows :
(1) To monitor the rate of impedance change in the solution, the constant current method is convenient.
(2) The four-electrode method used together with constant current can give stable impedance change for any metal wire electrodes with 0.7 mmφ.
(3) Cheap stainless steel wire is favorable for metal electrodes.

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The simple reaction time (RT) is studied for two groups of schizophrenic and normal subjects in order to clarify their “adaptability” to the simple task. The visual stimulation of constant interval (2 sec or 3 sec) is continuously imposed on the subject for about 10 minutes. The measurement of RT and the calculation of statistical quantities are carried out by using a measuring system made up of a microcomputer and some electronic circuits. Significant differences could be found between these two groups in the average value <RT>, standard deviation SD, serial correlation coefficient R₁, and abnormal RTs far-off <RT>. The reason of the difference is examined by other experiments including anticipation or preparation. As a result, the above difference can be understood to have arisen from the fact that schizophrenics have lower adaptability than normal subjects.

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The intravital microscope-television system already reported by the authors (JJBME 17, 1979), in which a two-channel sample hold scanner has been used to measure the microvascular blood flow velocity, was modified by introducing a one-bit correlator. The accuracy of velocity measurements by a new system and its applicability to blood flowmetry in microvessels have been examined by in-vitro and in-vivo experiments.
The correlator installed in the system made it possible to measure the real blood flow velocity automatically with inputs of the time-course signals from the two-channel sample hold scanner. Calibration experiments were performed by the rotating disk method and also by the in-vivo measurement of blood velocity in the rat mesentery with excellent results which follow : First, the peripheral speeds of a rotating disk marked by white radial lines were measured on the monitor TV screen. The measured velocity was found to agree well with the calculated one with a correlation coefficient of 1.0. Secondly, the flow velocity in the microvessels of rats obtained by correlation technique gave a good coincidence with that obtained by the previous method based on the visual measurement of delay time of blood flow signals.

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