Modeling sound generation in stenosed coronary arteries

Acoustic measurements obtained from sensitive microphones placed on the chest are being used in a procedure to noninvasively diagnose coronary artery disease. Utilizing specially developed signal processing techniques, the spectral content of isolated diastolic heart sounds has been estimated and usually shows an increase in high-frequency components in patients with occlusive coronary arteries. In order to establish a theory for the origin of these spectral features, a sound source model has been developed which combines an incremental network model of the left coronary artery tree with a transfer function model describing arterial chamber resonant characteristics. The network model predicts flow in both normal and stenosed coronary arteries. From this flow information, the arterial chamber transfer function model predicts the development of acoustic signals from the chamber resonant characteristics. The transfer function of a segment of coronary artery demonstrates two resonance frequencies. These resonance frequencies depend upon the length and diameter of the chamber segment, as well as upon the distal hydraulic impedance loading the segment. The lower resonance frequency can be excited by the usual flow fluctuations (low frequency) in the coronary artery. In cases of stenosis, the wideband spectral characteristics of the turbulence produced by the stenosis excites both the low and high resonance frequencies. In a small sample of patients, the spectra obtained from isolated diastolic acoustic signals recorded by a chest microphone agree well with those predicted by this theory.

Antitumor effect of a new organic selenium compound, 6-phenyl-7 (6H)-isoselenazolo [4,3-d] pyrimidone (ISP), on the growth of P388 mouse leukemia

The organic selenium compound, ISP [6-phenyl-7(6H)-isoselenazolo [4,3-d] pyrimidone] markedly inhibited the growth of P388 mouse leukemia at dose of 100 micrograms/mouse per day x 10 with no sign of toxicity. The antitumor activity of 4,5-dihydro-4-methyl-6-oxo-5-phenyl-6H-pyrazolo [4,5-c] isoselenazole (PIS) was weaker than that of ISP. The total lipid and phospholipid contents in the leukemic cells treated with ISP were significantly decreased. The fatty acid pattern of cholesterol esters, phosphatidyl choline and phosphatidyl ethanolamine from the ISP-treated P388 leukemic cells differed markedly from that of the corresponding lipids from the control leukemic cells. In addition, the synthesis of DNA or RNA was depressed in the ISP-treated leukemic cells. The present results indicate that ISP may open new perspectives in cancer chemotherapy.

MRI evaluation of left ventricular hypertrophy in a canine model of aortic stenosis

The progression of ventricular myocardial mass in nine puppies with experimental left ventricular hypertrophy and three controls was observed over a period of 7 months using magnetic resonance imaging (MRI). Left ventricular hypertrophy was created by surgically induced aortic stenosis when the puppies were 1 month old. Quantification of the progression of the left ventricular mass due to aortic stenosis as compared to the controls of similar age was then performed during the subsequent 7 months. Cardiac gated spin-echo technique was used for the imaging of the heart. Novel edge detection techniques were applied for automated identification of the border of the myocardium for measurement. Methods for correction of partial volume effect were applied in the analysis of the data. Clear-cut differences in myocardial mass (P less than .001) and in radius-to-wall thickness ratio (r/h, P less than .02) between puppies with aortic stenosis and controls were observed. The differences in end-diastolic volume between the two groups, however, were significant during the initial phase of hypertrophic compensation (P less than .001) and insignificant (P greater than .05) during the long-term phase of hypertrophic compensation. The results demonstrated that MRI is applicable in serial assessment of myocardial hypertrophy.

[Influence of septohippocampal lesion on the levels of some neurotransmitters and enzymes in the rat hippocampus]

Partial deafferentation of the hippocampus was obtained by transection of unilateral partial fimbria-fornix. On the seventh postoperational day, there appeared in the lesioned hippocampus respectively a 72.5%, 45.7% and 52.2% reduction in acetylcholine content, choline acetyltransferase and cholinesterase activity. A concomitant 16.3%, 31.1% and 30.3% reduction in noradrenaline, dopamine and serotonin content respectively was also observed, while amino acids content did not show any change. The results indicate that the cholinergic and monoaminergic afferents of the hippocampal formation in the rat reach their target regions via the fimbria-fornix.

Image processing on Macintosh II: a practical boundary finding algorithm for biomedical measurement

With increasing research interest in displaying and analyzing biomedical images, a practical personal computer based off-line image processing software would be useful. This paper describes the implementation of an image processing work station on a Macintosh II which features a novel edge detection capability useful for biomedical measurement. The boundary finding algorithm is coded in Turbo Pascal, and operates at a speed comfortable for interactive operation. Depending on the complexity of the problem, it usually takes less than a minute for the measurement of an image. The edge detection algorithm has an built-in edge detector with decision-making capability, and can be efficiently controlled by a mouse. In this way, the local accuracy of an automatic edge detection operator, and the global accuracy of the human eye (through manual control of a mouse) are combined.

Double-stranded RNA and male sterility in rice

Double-stranded RNA (dsRNA) was isolated from rice Oryza sativa ssp. japonica, but not from other subspecies. The dsRNA has been found in all of the examined cytoplasmic male-sterile (CMS) lines of BT (Chinsurah Boro II)-type rice, but was not detected in their companionate maintainer lines. It is uniquely and positivley correlated with the CMS trait in BT-type rice. Recently, the dsRNA was also found in a nuclear malesterile (NMS) rice, Nongken 58s, but was not found in its normal Nongken 58. The molecular weight of this dsRNA was estimated to be about 18 kb. Electron microscopic analysis reveals that it is linear snapped. The double strandedness of the RNA molecules was characterized by CF-11 cellulose column chromatography and nuclease treatments. It bound to CF-11 cellulose in the presence of 15% ethanol. It was sensitive to RNase A at low salt concentrations, but insensitive to DNase I, SI nuclease, and RNase A at high salt concentrations. The dsRNA was detected in both mitochondrial and cytoplasmic fractions. Dot-blot hybridization reveals that there is no sequence homology between this dsRNA and mtDNA, but there is homology between this dsRNA and nuclear genomic DNA. We have not been able to transmit this dsRNA to fertile rice.

The use of the ALOPEX process in extracting normal and abnormal visual evoked potentials

The ALOPEX method, a multiparameter stochastic optimization technique, is used for the optimal extraction of parameters in fitting randomly chosen action potentials to normal and abnormal visual evoked potential (VEP) waveforms. It is assumed that conformational changes in the abnormal VEPs can be attributed to an asynchrony in the arrival of action potentials at an integration point in the visual cortex. The results indicate that the assumption is valid in all five of the five records processed, of which two were normal and three abnormal. Further experimentation is needed to see if the method can be used as a diagnostic tool.

Lipogenesis stimulatory and inhibitory activities of the insulin mediators

Incubating plasma membranes prepared from pig liver with varying concentrations of insulin (50-1000 microU/ml) resulted in the release of at least two insulin chemical mediators. One of them was fraction 1 of insulin mediator (M. W. 3700-4000 daltons) which had a significant lipogenesis-stimulating activity. The other was fraction 2 of insulin mediator (M. W. about 1000 daltons) which exhibited a lipogenesis-inhibitory activity. The ratio of yield between the two mediators produced from the membranes was not only dependent on the concentration but also on the potency of insulin and its analogs added. The result showed that there was more production of fraction 2 than fraction 1 with the inducer at low concentration (100 microU/ml), while the production of fraction 1 from the plasma membranes incubated with high concentration of insulin (300 microU/ml) was higher than fraction 2. On the other hand, insulin and its analogs which have different biological activities and receptor binding activities have been used to induce the insulin mediators. The results obtained were similar to those mentioned above. This suggested that the generation of the mediators was dependent on the biological potences but not the binding activities.

[Podophyllic acid piperidyl hydrazone nitroxide radical and etoposide on nucleic acids and protein metabolism of leukemia L7712 cells in vitro]

Podophyllic acid piperidyl hydrazone nitroxide radical (GP-1) and etoposide (VP-16), derivatives of podophyllotoxin, inhibited DNA, RNA, protein and ATP synthesis of leukemia L7712 cells at a concentration of 5 micrograms/ml. Inhibitory extents were dependent on the exposure time from 3 to 24 h. The inhibitory rates of both drugs were about 15-66%. ID50 of GP-1 and VP-16 on the synthesis of L7712 cells at 24 h were 0.16 and 0.38 micrograms/ml, respectively. The dose-response curve of GP-1 was a parabolic one, while that of VP-16 was a straight line. The inhibition of GP-1 or VP-16 on DNA synthesis existed also after cells washing. It is suggested that the antitumor effects of GP-1 and VP-16 seem to be related to the damage of DNA template.

Incremental network analogue model of the coronary artery

From Newton's equation and the continuity equation, an equivalent analogue circuit model can be derived for each small segment of the coronary arteries. Sapoznikov divided the coronary artery tree into 116 segments. By replacing each segment with its analogue circuit model, a final incremental network model was derived. The model was tested using typical physical parameters under normal conditions, as well as in the presence of coronary artery stenosis. In the case of stenosis, the arteriolar flow with and without autoregulation were compared. The model shows good agreement with the reported effects of stenoses and heart rate on coronary blood flow.

[Paroxysmal kinesigenic choreoathetosis]

20 cases of paroxysmal kinesigenic choreoathetosis were reported. In this series, 90% cases were sporadic and the male predominated with a sex ratio of 5.7:1. The mean age of onset was 15 years old. The striking feature was the frequent brief tonic, dystonic or choreoathetoid attacks that were triggered by sudden movement, lasting no longer than 3 minutes. The paroxysms reached their climax during puberty with a frequency as much as 30-100 times per day. Spontaneous remissions came about at the age of 20 or so and the paroxysms seldom occurred after 30 years old. The attacks responded to Dilantin and L-dopa. In this series, not only were the attacks triggered by sudden initiation of movements followed a period of inactivity, but also triggered by sudden increase in speed, amplitude, force strength and a sudden addition of new actions during steady movements were in progress. It first called attention to the effect of alcohol on the attacks of the disease. It furnished PKC with a circumstantial evidence of a functional disorder of basal ganglia.

Variation of lateral ventricular volume during the cardiac cycle observed by MR imaging

CSF pulsation suggests variation in the size of the cerebral ventricles during the cardiac cycle. The arterial blood flow and venous outflow are two major components that contribute to the variation. High-resolution MR imaging with cardiac gating provides sharp delineation of the cerebral ventricles with clear boundaries. Subtle changes in the size of the ventricles during the cardiac cycle are measurable with high precision and accuracy by using a sophisticated automated edge-detection algorithm. In 12 normal individuals, the cerebral ventricles were examined, and the size of the lateral ventricles showed a 10-20% change during the cardiac cycle. The pattern is complex but similar in appearance to the intracranial pressure pulse waveform. The variation suggests that the choroid plexus may play a greater role as a source of CSF pulsation that currently acknowledged. The ability to measure the variations in ventricular volume has clinical implication as a noninvasive method for the diagnosis of diseases with abnormal brain elasticity.

A new DNA immune adsorbent for hemoperfusion in SLE therapy: a clinical trial

This investigation studied the preparation and clinical trial of DNA immunoadsorbent for hemoperfusion in systemic lupus erythematosus (SLE) therapy. DNA was complexed with blue tetrazolium (BT), then mixed with collodion, and finally adsorbed on macroporous spherical polymeric adsorbent. The percentage of DNA thus immobilized was 98-98.5%, and no release was detected during hemoperfusion. A patient with severe SLE was treated with the above adsorbent in hemoperfusion. The patient was in coma, with high anti-DNA antibody and abnormal immune complex levels, which fell sharply from 56.34% to 0.8% after 2.5 h of whole-blood hemo perfusion. There were no major clinical complications, and 2 weeks later, her proteinuria level became normal and immune complex levels were sustained. She was then discharged from the hospital and has been in good health for more than 1 year.

The role of insulin mediators in regulation of cAMP and lipogenesis as well as in diabetes

Plasma membranes prepared from pig, mouse and rat liver incubated with insulin resulted in the release of at least two insulin chemical mediators. These mediators, identified as fractions 1 and 3, were found to inhibit cAMP level in response to lipolytic hormone and forskolin and to enhance lipogenesis in adipocytes of rat. Fractions 1 and 3 have been estimated to have molecular weights of 3700-4000 and 1000-1500 dalton, respectively. This initial report will focus on fraction 1. Interestingly, liver membranes from diabetic animals were found not to release mediators in the presence of insulin. However, following in vivo treatment of diabetic animals with insulin, the liver membranes appeared to restore its ability in generating chemical mediators in response to insulin.