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Biomedical subjects

S I Saffer

Publications and source records attributed to S I Saffer.

6 recordsLinked to original sources
PubMed1983

Three-dimensional echoventriculography.

A method of generating a three-dimensional image of the human left ventricle by computer techniques is described. The volume of each image was estimated by a modification of Simpson's rule. The method was applied to nine suitable patients and estimations of end-diastolic and end-systolic volumes were compared to volumes determined by cineangiography. Significant linear correlation coefficients of 0.95 and 0.94 were obtained for end-diastolic and end-systolic volumes, respectively. The standard errors of estimate were 9 ml for end-diastolic volumes and 7 ml for end-systolic volumes. The value of this methodology lies in the ability to estimate left ventricular volumes with accuracy, using an imaging technique of little inconvenience and no risk to the patient and computer hardware that is readily available at most clinical institutions.

Adult↗
PubMed1981

Effects of severe dopamine depletion on dopamine neuronal impulse flow and on tyrosine hydroxylase regulation.

Reserpine depletes dopamine (DA) levels and increases tyrosine hydroxylase (TH) activity in the rat corpus striatum. TH is activated not only by enhancement of DA neuronal impulse flow, but also by cessation of impulse flow. To assist in the understanding of the relative contribution of impulse flow to the regulation of TH activity in the DA depleted neuron, we examined the consequences of severe DA depletion on substantia nigra DA neuronal impulse flow and on in vivo TH activity in the rat corpus striatum. One day after reserpine or 30 min after the reversible reserpine-like compound, Ro4-1284, striatal DA levels were severely depleted and in vivo TH activity was enhanced about three-fold. DA depletion was found to significantly increase DA neuronal impulse flow. Although the DA neuron is firing faster than normal in the DA depleted rat, because there is no DA being released it is still not clear whether the elevation in TH activity is due to the enhancement of impulse flow or to the lack of DA at presynaptic receptor sites, or both. gamma-Butyrolactone (GBL), causes a cessation of DA neuronal impulse flow and activates TH by a presynaptic autoreceptor mechanism. GBL inhibited by over 50 percent the elevation in TH activity produced by severe DA depletion. This finding suggests that the enhanced TH activation after DA depletion in in large part due to increased DA impulse flow. Furthermore, the TH activity seen with GBL in DA depleted rats was significantly less than that seen after GBL administration in normal rats. This finding is consistent with the hypothesis that the DA storage granule also plays a role in TH regulation.

4-Butyrolactone↗
PubMed1980

A computer-based scintigraphic method for sizing acute inferior myocardial infarcts.

A modeling procedure, employing multiple 99mTc-PYP myocardial scintigrams, was applied to acute inferoposterior myocardial infarcts in 12 dogs. Four modeling schemes were developed, and the model volume predictions were correlated with morphometrically determined infarct masses. Correlation values ranged from r = 0.66 (p less than 0.02) to r = 0.80 (p less than 0.005), suggesting that the method may enable noninvasive quantitative sizing of acute inferoposterior myocardial infarcts.

Animals↗
PubMed1979

A comparison of mathematical models for estimating right ventricular volumes in animals and man.

Volume of 19 right ventricular canine casts and 11 right ventricular human casts were obtained by water displacement and compared to three different mathematical models for estimating right ventricular volumes by biplane cineangiography. In the canine studies, significant linear correlation coefficients were obtained using the longest measured length method (r = 0.92), the triangular modification of Simpson's rule (r = 0.93), and the elliptical modification of Simpson's rule (r = 0.93). The human studies resulted in similar significant correlation coefficients of 0.96, 0.97, and 0.97, respectively. Although the highest correlation with the lowest standard error of estimate was obtained using the triangular model, all three mathematical models produced volume estimations that feel within acceptabe biological limits of accuracy.

Animals↗
PubMed1976

Simple method for computer-aided analysis of echocardiograms.

The use of echocardiography in the diagnosis and assessment of heart disease is increasing as greater familiarity is obtained with this noninvasive procedure. Quantitative evaluation of echocardiographic studies has heretofore required time-consuming manipulation of mathematical formulas. A simple method utilizing a sonic digitizing tablet has been developed for computer-aided analysis of M-mode echocardiograms. This device can convert a point located manually with a digitizing pen into X and Y coordinates and with use of the standard telephone network can communicate on a time-shared basis with a DECSYSTEM-10 computer. A program has been written to compute and type the results of standard calculations involving mitral valve motion and left ventricular function. The information can also be stored on disk by the computer for future use. This simple, relatively inexpensive system is valuable because of the ease with which it permits usually laboriously obtained information to be extracted from the standard echocardiogram.

Diagnosis, Computer-Assisted↗