Adsorbents, for direct hemoperfusion, 1: Resin (XAD-4, XAD-8, XAD-12, XE-284), 2: coconut broken charcoal, 3: bead-shaped activated carbon were examined to use as a material of artificial kidney.
XE-284 effectively cleared urea from its solution, H⁺ release was however recognized during urea clearance. Coconut broken charcoal (CB-812A) was encapsulated with collodion and coated by albumin for direct hemoperfusion. After one hour direct hemoperf usion in acute uremic dogs of bilateral ureters ligation, serum creatinine level was efficiently lowered, but platelets and white blood cells were reduced. A few emboli were seen in alveolar capillary of the lungs.
Bead-shaped activated carbon is fairly hard and uniformly spherical. Serum creatinine was removed effectively after two hours hemoperfusion with this doubly coated charcoal and HFK in series. Histological examination of sacrificed dogs after hemoperfusion could not detect any embolus in alveolar capillary of the lungs.
Bead-shaped activated carbon which can adsorb many substances over the wide molecular range, is now considered not harmful material for clinical use, because of no troublesome fine particle release and less platelets depletion.

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The effects of left ventricular bypass between LA and AO, on right ventricular contraction were studied. Using straingauge arch, attached on each ventricular wall pararell to fibers of superficial bulbospiral muscle, changes of contraction displacement of left and right ventricular walls were measured. Bypass pump, utilized in this study was pneumatic driven type and made of polyurethane, bearing Björk-Shiley prosthetic valves as inflow and outflow valves. No significant decrease of left ventricular end-diastolic and peak pressure and no significant change of each ventricular contraction displacement were observed when bypass ratio was less than 50% of total cardiac output. Significant decrease in left ventricular peak pressure, left ventricular end-diastolic pressure, left ventricular contraction and right ventricular contraction displacement were observed when bypass ratio was increased from 60 to 90% of total cardiac output.
During LA to AO left heart bypass, with high bypass ratio, end-diastolic left ventricular volume decreased with resulting decrease in left ventricular contraction force. Right ventricular contraction, which is dependent on left ventricular contraction to the considerable degree, would be secondarily decreased according to decrease in left ventricular contraction. Consequently, in clinical use of this type of left heart bypass for the patients who are also associated with right ventricular failure, LA-AO left heart bypass with too high bypass ratio should be avoided to prevent right ventricular dysfunction.

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An accurate measurement of the stimulation rate of the implanted cardiac pacemaker (PM) is prime importance to increase its longevity or to find its battery exhuastion. Accordingly, we developed two types (I and II) of interval counter and one type (III) of rate counter. Both counters were specially designed for PM. All were equipped with quartz control for accuracy and with digital desplay for easiness.
First of all, to design the sensitivity of the counters, skin surface voltage of the PM impulse was measured and mapped in each of 25 patients (20 of monopolar and 5 of bipolar electrodes in use).
The sensitivity characteristic of type I counter is similar to ECG. It responds well to QRS or muscular potential other than PM impulse. It has often electrical interference from the outside. Then type II counter was developed and which is more selectively sensitive to the PM imulse. It responds well to PM but less to interference.
Type III is battery powered counter. It is much smaller than previous types and is 13.0×7.0×2.3cm in size. The sensitivity function is similar to type II. The counter has only an on-off push button switch. It does not require any complicated procedure. Upon clinical use, the counter electrodes are placed on skin where the PM generator is implanted. The PM rate is immediately displayed on digital. The counter is so simply designed that patient can use it without any difficulty.

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