[Experimental and clinical studies of an ampicillin suppository (KS-R1) in pediatrics]

Blood levels of ampicillin (ABPC) were measured in 10 childish patients with heart disease after the rectal administration of KS-R1 at doses of 125 mg and 250 mg. Average blood levels of ABPC at 15, 30 minutes, 1, 2 hours and 4 hours after the administration of KS-R1 were 6.8, 6.9, 3.1, 1.1 mcg/ml and 0.1 mcg/ml with half-life of 0.64 hours in patients of age from 1 year to 4 years 7 months old (dose level 8.9 approximately 13.9 mg/kg, average 10.5 mg/kg), and 5.2, 6.1, 3.4, 1.0 mcg/ml and 0.1 mcg/ml with half-life of 0.65 hours in patients of age from 7 years 10 months to 10 years 7 months old (dose level 8.3 approximately 13.9 mg/kg, average 9.8 mg/kg), respectively. Clinical effective rate (excellent and good) was 87% in 55 childish patients with infections. Bacteriologically, 13 strains (74%) out of 18 strains which were isolated from the patients were eradicated. No severe side effects were observed. Diarrhea was observed in 3 cases.

Effect of regional ischemia on the left ventricular end-systolic pressure-volume relationship of isolated canine hearts

We studied the effects of regional ischemia on the left ventricular isovolumic end-systolic pressure-volume relationship (ESPVR) in six excised, blood-perfused canine ventricles. We created different extents of regional ischemia by ligating various branches of the coronary arteries while keeping the coronary arterial pressure constant (80 mm Hg). The extent of regional ischemia (Rm) relative to the total mass of the left ventricular myocardium was determined by regional myocardial blood flow measured by the radioactive microsphere technique. With regional ischemia, the ESPVR shifted rightward without significant change in slope in the physiologic end-systolic pressure range. In the subphysiological end-systolic pressure range, however, its slope became lower than control. In order to quantify the degree of the rightward shift, we measured the extrapolated volume axis intercept (Vo) by fitting a straight line to the ESPVR in the physiological range under control and ischemic conditions. The shift in Vo (delta Vo) associated with ischemia was linearly correlated with Rm (delta Vo = 50.7Rm-0.6, n = 28, r = 0.944, P less than 0.001). We conclude that the major effect of acute regional ischemia on the ESPVR in the physiological pressure range is a parallel rightward shift. This forms a striking contrast to the effect of global ischemia (under which only the slope is affected without a substantial change in Vo).

[The experimental and clinical studies on cefsulodin in the pediatric field]

A new cephalosporin cefsulodin (CFS) was studied basically and clinically and the following results were obtained. 1. The serum levels of 25 mg/kg of CFS administered intravenously were 39.5 mcg/ml after 30 minutes, 22.6 mcg/ml after 1 hour, 11.6 mcg/ml after 2 hours, 6.0 mcg/ml after 4 hours and 2.1 mcg/ml after 6 hours. The half life from serum was 84 minutes. 2. Clinical response on 4 cases of Pseudomonas aeruginosa infections were all good. 3. The slight elevations of GOT, GPT were observed by the drug administrations in 1 case. From the above results, CFS was effective drug to P. aeruginosa infections by intravenous administration of 25 mg/kg of CFS.

Impedance loading servo pump system for excised canine ventricle

To investigate ventricular-arterial system interaction, we have developed a hybrid-computer-controlled impedance loading servo pump system that enables us to impose a simulated arterial hydraulic impedance on an excised canine ventricle. An analog computer programmed to simulate a three-element Windkessel model of the arterial system computes instantaneous aortic flow from the instantaneous ventricular pressure. The time integral of this flow is used to command a volume servo pump system that controls the instantaneous ventricular volume. All parameter values in the loading system are controlled by a digital computer. The actual impedance spectrum generated by the system was reasonably close to that expected from the arterial model. The unique features of this system are the following. 1) The instantaneous volume of the ventricle, which is crucial information, can be measured. 2) If needed, the arterial impedance model can easily be reprogrammed to generate more complex impedance spectra. 3) The vascular parameters can be made nonlinear or time varying through the digital computer control.

Microprocessor control of a ventricular volume servo-pump

Measurement of the instantaneous pressure-volume relationship of the left ventricle is fundamental to the study of ventricular mechanics. In order to effectively investigate this relationship, it is necessary to vary and control the time course of ventricular volume change in a variety of prescribed manners. In the past, we used an analog circuit to generate command signals for a servo-pump system which controlled ventricular volume. The use of analog control limited the variety of volume waveforms which could be generated. To overcome this limitation, we developed a new system in which the servo-pump is controlled by an inexpensive microprocessor based computer, capable of generating an unlimited repertoire of volume waveforms. The computer system also made possible the use of adaptive control to increase the system fidelity. Finally, such a system provides for ease of adjustment to new hardware, should future research require it.

Effects of coronary arterial pressure on left ventricular end-systolic pressure-volume relation of isolated canine heart

In the excised canine left ventricle, the end-systolic pressure-volume relationship (ESPVR) has been shown to be approximately linear over the working range of loading conditions when coronary arterial pressure (CAP) is maintained constant, independent of loading conditions. To investigate the ESPVR under the more intact physiological condition in which the CAP varies with loading on the left ventricle, we studied the effect of changes in CAP on the ESPVR in 10 excised cross-circulated canine ventricles which were contracting isovolumically. The ESPVR, determined from isovolumic contractions at four different volumes, was reasonably independent of CAP as long as CAP remained above a critical pressure (67.0 +/- 22.1 mm Hg). Below this pressure, the slope of ESPVR decreased although the volume axis intercept (V0) remained unaltered. These findings indicate that under physiological conditions, where there is a close coupling of CAP to systolic left ventricular pressure, the ESPVR should become nonlinear in the low preload or afterload regions. When CAP was varied with the left ventricular pressure in five ventricles, the ESPVR indeed became nonlinear in the low-load region. We conclude that the ESPVR in intact conditions is reasonably linear in the physiological load range, but it can be nonlinear in the low-load range.

Left atrial ball thrombus diagnosed by two-dimensional echocardiography

The diagnosis of the ball thrombus in the left atrium has been very difficult by conventional clinical techniques. In the present case, two-dimensional echocardiography successfully demonstrated a spherical tumor moving in unpredictable directions in the left atrium. M-mode echocardiography did not clearly identify the tumor because of the limited visual width and spatial orientation of the technique; however, simultaneous recordings of the M-mode echocardiogram with phonocardiogram, carotid pulse wave, and electrocardiogram provided some diagnostic clues to the occlusive left atrial tumor. In the absence mitral valve occlusion by the tumor, a logarithmic correlation between the ejection time and the preceding R-R interval, and a negative lines correlation between Q to the first sound interval and the preceding R-R interval were found. In the beat following the appearance of the tumor in the mitral orifice, the sudden shortening of the ejection time and the prolongation of Q to the first sound interval were noted. Both of these findings are indirect evidence of decreased left ventricular filling associated with an elevated left atrial pressure resulting from the sudden mitral orifice obstruction by the tumor. Detailed analysis of the data obtained by the conventional noninvasive techniques could provide critical clues for the diagnosis of the occlusive left atrial tumor.

[Experience with cefuroxime in pediatric field (author's transl)]

Having resistance to beta-lactamase-producing strains and showing resistance to not only cephalosporin resistant strains of E. coli and Klebsiella but also to Citrobacter, Proteus and Enterobacter, Cefuroxime (CXM) was used in pediatric field for both fundamental and clinical studies. CXM was found to be a useful antibiotic in views of high clinical efficacy rate obtained and no side effect noted. As for the dose, the single dose of 25 mg/kg achieved sufficient blood levels. Also in view of good clinical effect, the dose of 25 mg/kg three or four times daily seems appropriate for treatment of children.

[Study of S-6437 in pediatrics regarding clinical efficacy, blood levels and urinary excretion (author's transl)]

S-6437 was orally given to 29 patients of 3 months to 12 years and 6 months of age who had respiratory or urinary tract infections. The daily dose used was 25 to 60 mg/kg divided in two doses. The following is the results of this study: 1. With 25 approximately 60 mg/kg/day, satisfactory results were obtained for upper respiratory tract infections. In lower respiratory tract infections, however, the effectiveness seemed not to be so good as that in upper respiratory tract infections. 2. Side effects such as diarrhea, loose stool, abdominal pain and eruption were observed but they were temporary. Therefore, the administration of S-6437 was not discontinued due to such side effects. 3. S-6437 was acceptable to elder children but some of children of 2 approximately 4 years of age disliked this preparation because it was not smooth in their mouths. Therefore, the preparation of S-6437 should be further improved. 4. Since it has been recognized that blood levels of cephalexin following the administration of S-6437 last for a longer period of time than regular cephalexin, S-6437 is considered to be a useful preparation. 5. B.I.D. and T.I.D. regimens of S-6437 will give clinical satisfaction to children over 6 years and ones under 6 years, respectively.