PubMed Health⌕ Search

Biomedical subjects

R Sarper

Publications and source records attributed to R Sarper.

12 recordsLinked to original sources
PubMed1993

Assessment of splanchnic blood flow in alcohol and drug abuse using radionuclide angiography.

Computerized radionuclide angiography (RA) is a noninvasive, quantitative, reproducible, and cost-effective method for measuring the portal venous fraction of total hepatic blood flow (represented by the Hepatic Perfusion Index, HPI), and also can be utilized to detect hemodynamic abnormalities in the spleen. A group of 105 men (aged 20-56) were evaluated at the time of admission to the Substance Abuse Program at the Department of Veterans Affairs Medical Center. These patients were classified into three groups: (a) alcohol dependence or abuse (Group A, n = 54); (b) polysubstance abuse without alcohol (Group B, n = 9); and (c) polysubstance abuse with alcohol (Group C, n = 42). Of the respective groups, 69%, 100%, and 79% had abnormal splanchnic flow (liver and/or spleen), whereas only 43%, 78%, and 48% had abnormal liver function tests. This method may be a sensitive, noninvasive detector of early pathophysiological changes in the splanchnic organs of alcohol and drug abusers.

Adult↗
PubMed1988

Treatment of tyramine-induced brain edema with anion transport inhibitor L-644,711.

Tyramine induces coma in phenelzine-treated dogs. Development of coma in these animals is associated with brain edema, abnormal brain scans of Tc-99m-diethylene-triamine-penta-acetic acid (Tc-99m-DTPA), and elevated levels of CSF catecholamines. We found that the intravenous administration of 6-7 mg/kg of a single dose of L-644,711 given fifteen minutes after the oral administration of tyramine to phenelzine-pretreated animals followed by an infusion of normal saline containing 6-7 mg/kg of the drug given over a period of 2 hr caused reversal of brain injury. This was accompanied by full recovery within a period of 24 hr of all the animals tested. A follow-up study revealed that 24 hr after treatment with L-644,711 CSF levels of catecholamines and brain images of Tc-99m-DTPA were indistinguishable from normal controls. Animals that received no drug died from unresolved coma within 4 to 24 hr. Animals that had recovered due to therapy with L-644,711 were given 10-14 days rest followed by a repetition of the phenelzine and tyramine treatment but denied L-644,711 therapy. These animals also died of unresolved coma within 24 hr. This preliminary study suggest that the use of L-644,711 may constitute an important advance in treatment of brain edema of a wide range of neurological disorders.

Animals↗
PubMed1987

Quantitative evaluation of brain edema by radionuclide imaging technique.

The objective of the present investigation was to quantify metabolic cerebral edema in dogs with impaired monoamine oxidase (MAO) function and liver disease using dynamic imaging of the brain with 99mTc-diethylenetriamine pentacetic acid (99mTc DTPA). Data acquisition was started following a rapid intracarotid injection of 99mTc DTPA (5 mCi), and sixty 0.5-s images of the left or right hemisphere were taken. First-pass time-activity curves were obtained by selecting regions of interest for the appropriate brain hemisphere. The results of this study demonstrated that in phenelzine-treated animals there was a 6 to 38% reduction in brain washout slopes of 99mTc DTPA (24.0 +/- 11.5% reduction). These washout slopes were further reduced (range 24.0-86.0; 50.6 +/- 18.5% reduction) following the oral administration of tyramine (1 mg/kg). A significant correlation was noted between changes in washout slopes and the development of coma in these animals.

Animals↗
PubMed1987

Tyramine neurotoxicity and first-pass brain technetium-99m-diethylenetriamine penta-acetic acid.

Tyramine induces coma in phenelzine-treated dogs with liver disease. The objective of the present investigation was to examine the influence of tyramine in these monoamine oxidase-inhibited dogs on the kinetics of Tc-99m-diethylenetriamine penta-acetic acid (Tc-99m-DTPA) during its first passage through the brain by nuclear imaging techniques. The study began with anesthetized mongrel dogs (n = 10) in a supine position over the camera detector. Data acquisition was started simultaneously after the rapid intracarotid injection of Tc-99m-DTPA (5 mCi) and 60 0.5-sec images of the brain were taken. Tyramine induced increased uptake with a concomitant impairment in the elimination of Tc-99m-DTPA from the brain of these phenelzine-treated animals with hepatic injury (n = 5) as compared to pretreated animals serving as a control group or phenelzine-treated animals without liver disease. This was accompanied by an appreciable reduction in hemispheric cerebral blood flow (50.5 +/- 19.3 vs. 110 +/- 16 ml/100 g/min), respectively. Increased cerebrovascular permeability of Tc-99m-DTPA and decreased cerebral blood flow occurred concomitantly with increased cerebrospinal fluid pressure and elevation in cerebrospinal fluid catecholamines of monoamine oxidase-inhibited animals with hepatic injury.

Animals↗
PubMed1984

Preparation and biodistribution of 99mTc-labeled tyramine iminodiacetic acid.

The synthesis and biodistribution properties of 99mTc-labeled N-substituted tyramine, [N-(4-hydroxyphenethyl)iminodiacetic acid] are described. Tissue distribution studies in rats were indicative of high hepatic and kidney extraction, accompanied by rapid plasma and urinary clearance and minimal biliary excretion. These findings were substantiated by organ image analysis. The preliminary data indicate that this labeled material may represent a new class of radiopharmaceuticals for the evaluation of hepatic and renal functions.

Animals↗
PubMed1983

An improved method of estimating the portal venous fraction of total hepatic blood flow from computerized radionuclide angiography.

The measurement of portal venous flow to the liver is important in the evaluation of patients for shunt surgery. A previous report described a method using slope analysis of hepatic radionuclide angiograms to generate an index of relative portal flow, which correlated well with angiographic grades of portal perfusion. The present report describes a refinement in bolus administration and a modification in technique that appear to reflect true portal venous flow more accurately. A total of 109 studies was performed, including seven normal and 80 cirrhotic patients. The method was reproducible (r = 0.998) and showed good correlation with the angiographic grades of perfusion (r = -0.906).

Humans↗
PubMed1982

Multiimage formatting: effect on scintillation image quality.

Multiimage formatters designed for use with scintillation cameras allow convenient presentation of as many as 90 images on a single film. Three different multiimagers (Searle Microdot 3132, Toshiba Gamma Imager GMI-04A, and Matrix Multi-imager 4) were evaluated with phantoms. Image quality was not equivalent in all positions on the resultant film, and was unacceptable in some cases. Individual laboratories should be aware of the potential loss of diagnostic information when using multiimage formatters and should evaluate their devices for this potential problem.

Image Enhancement↗
PubMed1981

Radionuclide angiography of the liver and spleen. Noninvasive method for assessing the ratio of portal venous to total hepatic blood flow and portasystemic shunt patency.

Radioactivity verus time curves were generated for the first pass of technetium-99m pertechnetate through the left ventricle, kidneys, spleen and liver, after a 20 mCi peripheral intravenous bolus injection. The rate of change of radioactivity in these organs before recirculation is proportional to blood flow through the organ. The hepatic perfusion index, defined as the ratio of portal flow to total hepatic blood flow, was correlated with the angiographic grade of portal perfusion. The hepatic perfusion index in seven normal subjects was 66.0 +/- 3.4 percent (mean +/- standard error of the mean), and in 22 cirrhotic patients with decreasing angiographic perfusion of grades 1 to 4 the index was 54 +/- 4.6, 37 +/- 2.6, 17 +/- 4.7 and 3 +/- 1.1 percent, respectively. The correlation between the calculated perfusion index and the angiographic grade of portal flow was highly significant (p less than 0.001). The passage of radionuclide through the spleen differed before and after shunt surgery in patients with portal hypertension. The slope to height ratio, based on the downslope of the splenic curve, was significantly greater (p less than 0.01) in the shunted patients and provided a simple index for assessing shunt patency.

Adult↗
PubMed1981

A noninvasive method for measuring portal venous/total hepatic blood flow by hepatosplenic radionuclide angiography.

Radionuclide angiography was used to generate first-pass radioactivity vs. time curves for the left heart, right hepatic lobe, right lung, spleen, and both kidneys following rapid intravenous injection of 20 mCi (740 MBq) of 99mTc-pertechnetate. Seven normal subjects were examined as well as 57 cirrhotic patients, who also underwent angiographic grading of portal venous perfusion. For analysis, two time points were identified: (a) t0, when 99mTc first entered the liver (the initial rise of either curve); and (b)tc, when 99mTc was maximal in abdominal organs (the renal peak). Analysis was based on the slopes of the two phases of the hepatic curves t0 + 7 seconds and Tc + 7 seconds; this time selection permitted analysis of all curves. The hepatic perfusion index (HPI) = slope (tc + 7 secs)/slope (t0 + 7 secs) + slope (tc + 7 secs). The mean HPI for the normal subjects was 66% +/- 7; for the cirrhotic patients with angiographic Grades I, II, III, and IV, the HPI was 52% +/- 9, 37% +/- 6, 15% +/- 7, and 3% +/- 4, respectively. Correlation between HPI and angiography was significant (p less than 0.001). This method offers a readily available, rapid, relatively inexpensive, and quantitative method of grading the ratio of portal venous to total hepatic blood flow.

Adult↗
PubMed1981

Enhanced detection of metastatic liver disease by computerized flow scintigrams: concise communication.

The purpose of this study was to develop a method by which the sensitivity of radionuclide liver imaging for the detection of hepatic metastasis could be enhanced. Routine flow studies were performed before imaging by injecting the usual 2-3 mCl dose of Tc-99m sulfur colloid as a bolus and storing 30 2-sec images in a computer. With regions selected by light pen, curves were generated from the right lobe of the liver, the right kidney, and the descending aorta. The peak of the kidney curve was chosen as a marker to separate the arterial and venous phases on the liver curve. The average slopes of four points on the liver curve before this marker, and four after, were calculated and the ratio of the first slope to that of the second was defined as the arterialization index. In this study with 228 patients, the inclusion of this index raised the sensitivity from 85 to 100%.

Aorta↗