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C D Russell

Publications and source records attributed to C D Russell.

At least 73 records · Page 4Linked to original sources
PubMed1985

Measurement of glomerular filtration rate using 99mTc-DTPA and the gamma camera: a comparison of methods.

A variety of methods have been proposed to estimate the glomerular filtration rate (GFR) from the renal uptake of technetium Tc 99m-DTPA using a gamma camera. To compare alternative methods, we calculated the GFR in several different ways from measurements in 33 patients and compared the results with an independent GFR measurement based on eight-point plasma clearance of ytterbium Yb 169-DTPA. The best agreement was obtained using an algorithm that has not been described previously, in which correction was made for overlap of the kidneys by the liver and spleen. The correlation coefficient was 0.958, and the residual standard deviation was 12.1 ml/min. This method required a single 20-min blood sample as well as the camera data. The best method not requiring a blood sample was significantly less accurate, with a correlation coefficient of 0.837 and a residual standard deviation of 23.1 ml/min. The accuracy of these methods was comparable to that reported for creatinine clearance, the most commonly used estimate of the GFR in current clinical practice.

Glomerular Filtration Rate↗
PubMed1985

Measurement of glomerular filtration rate: single injection plasma clearance method without urine collection.

Glomerular filtration rate (GFR) can be calculated from the plasma clearance of any of several radiopharmaceuticals that are excreted by glomerular filtration. Simplified methods have been proposed that require only one or two plasma samples in lieu of a more complete clearance curve. We examined the error introduced by this simplification. Forty patients were studied using a dual-isotope technique employing [99mTc]DTPA and [169Yb]DTPA, obtaining eight plasma samples for each clearance curve at intervals from 10 to 240 min after injection. Data were fit to several empirical or semiempirical formulae and also to a two-compartment computer model that permitted GFR estimation from only one or two data points. The computer model gave good fit, but so did several simpler methods. The error that results from replacing the complete clearance curve by a single 3-hr sample was about 8 ml/min (residual s.d.). By using two samples (at 1 and 3 hr), the error could be reduced to 4 ml/min. Recommended one- and two-sample methods are presented.

Glomerular Filtration Rate↗
PubMed1984

Mean ionic charge on two components of technetium pyrophosphate prepared using stannous chloride.

Ionic charge, complexation equilibria, and acid-base equilibria can be measured at tracer concentrations by ion-exchange chromatography. To characterize better the principal components found in [99mTc]pyrophosphate preparations used for diagnostic bone and heart scanning, these were studied in two ion-exchange chromatographic systems: (A) DEAE-cellulose in pyrophosphate form at pH 6.0-7.5, and (B) DEAE-cellulose in perchlorate form at pH 3.7-4.8. The chromatographic retention times were measured as a function of pH and electrolyte concentration, and compared with those of trisoxalatochromium(III) complex, which was chosen as reference ion because of its similarity in charge and retention to the Tc-pyrophosphate complexes. The pyrophosphate complexes were even more sensitive to electrolyte concentration than was the triply negative reference ion: the calculated mean net charge in the mobile phase for the two principal Tc-pyrophosphate species were -4.5 +/- 0.5 and -4.9 +/- 0.5 at pH 4.3, and -11.2 +/- 1.3 and -10.1 +/- 1.0 at pH 7.0. It can be concluded that the two principal radioactive components in clinical Tc-pyrophosphate preparations both bear a high, pH-dependent negative charge.

Chromatography, Ion Exchange↗
PubMed1983

Quality control of Tc-99m DTPA for measurement of glomerular filtration: concise communication.

When technetium-99m DTPA is used to measure glomerular filtration rate (GFR), the accuracy depends on the supplier of the radiopharmaceutical. The error in GFR is due to protein binding, as we have shown by direct measurement. In 19 patients, GFR measured with Tc-DTPA and corrected for protein binding agreed with that measured simultaneously using Yb-169 DTPA (correlation coefficient 0.991). Without correction, Tc-DTPA gave falsely low values in patients having good renal function, in whom unbound activity cleared rapidly while bound activity remained in the circulation. When Tc-DTPA is used to measure GFR, the in vivo protein binding should be measured and used to correct the data.

Animals↗
PubMed1982

Iminodiacetate complexes of technetium: an electrochemical study.

Iminodiacetate complexes of technetium are used extensively in diagnostic medical imaging, but their chemical structure and properties are yet uncertain. We studied formation of technetium-99 complexes with diethylenetetraminepentaacetate (DPTA), ethylenediaminetetraacetate (EDTA), N-(2-acetamido)iminodiacetate (ADA), and N-(2,6-dimethylphenylcarbomoylmethyl)iminodiacetate (HIDA) by tast (sampled DC) polarography, reverse-pulse polarography, controlled-potential coulometry, and amperometric titration. The products, often mixtures, varied with reaction conditions and ligand; this can explain apparent contradictions in previous studies.

Edetic Acid↗
PubMed1982

Quantitation of renal function with glomerular and tubular agents.

Quantitative methods to measure the glomerular and tubular function of the kidneys with radionuclides have been available for many years. They have not been widely used because the techniques and the calculations exceeded the scope of routine nuclear medicine practice. Validation of simplified methods and the introduction of computer technology have made measurement of the effective renal plasma flow (ERPF) and the glomerular filtration rate (GFR) simple enough so that they can be performed reproducibly in most nuclear medicine departments. The estimation of ERPF with radioiodinated OIH and GFR with 99mTcDTPA can be achieved in many ways, all of which yield clinically useful results. How to get the best results using the simplest methods is still unclear. The required accuracy depends on the intended clinical use. Our preference at the present time is to use a single or double plasma sample to calculate global ERPF or GFR, and to use the 1-2 min OIH or 1-3 min Tc-DTPA uptake to calculate relative function of the two kidneys (split function ERPF or GFR). The choice of method will be influenced by local factors, such as the nature of the patient population, the case volume, and the resources available. A desirable goal for future studies is to document carefully the capabilities and limitations of each alternative method, so that the choice can be rational.

Computers↗
PubMed1980

Determination of net ionic charge on Tc-99m DTPA and Tc-99m EDTA by a column ion-exchange method.

The net charge on a stable complex ion is conveniently measured at tracer levels by studies of ion-exchange equilibrium. Previous applications to radiopharmaceuticals have used a batch equilibrium method, but such measurements are affected by any radiochemical impurities present. Since technetium pharmaceuticals are often heterogeneous, it is of value to have a technique that is directly applicable to a mixture of different species. Such a method is presented here: a column method to determine the net charge on the technetium-99m complex of diethylenetriaminepenta-acetic acid (DTPA), and also on the principal component in a mixture of species formed by reducing pertechnetate in the presence of ethylenediaminetetra-acetic acid (EDTA). The net charge was calculated from the effect of eluent concentration on retention time. The net charge on Tc-DTPA was found to be -2 at both pH 4.6 and 7.0. The net charge on the Tc-EDTA complex, measured at pH 7.0 only, was also -2.

Chemical Phenomena↗
PubMed1980

Complexes of technetium with hydroxycarboxylic acids: gluconic, glucoheptonic, tartaric, and citric.

Technetium complexes of several hydroxycarboxylic acids are used for medical imaging. To determine the oxidation state of technetium in these agents, we studied the reduction of pertechnetate (Tc-99) in 0.1 M solutions of four hydroxycarboxylic acids, using polarography and amperometric titration with Sn(II). In D-gluconate below pH 6, Tc(III) and Tc(V) complexes were identified with certainty, Tc(IV) questionably; at pH 6 to 10, Tc(IV) and Tc(V) were formed; above pH 10, Tc(III), Tc(IV), and Tc(V). In D-glucoheptonate below pH 6, Tc(III) and Tc(V) were formed, and questionably Tc(IV); at pH 6 to 10, Tc(V); above pH 10, Tc(III), Tc(V), and probably Tc(IV). In L-tartrate below pH 6, Tc(III), Tc(IV), and Tc(V) were formed; above pH 6, Tc(IV) and Tc(V). In citrate below pH 10, Tc(III), Tc(IV), and Tc(V) were formed; above pH 10, Tc(IV) and Tc(V). For all four ligands the initial product of reduction by Sn(II) at pH 3 to 9 was Tc(V). In freshly prepared tin-labeled imaging agents of this class, the oxidation state is probably Tc(V). Lower stable oxidation states exist, attainable by using reducing agents stronger than tin; these may show altered imaging properties.

Carboxylic Acids↗
PubMed1979

Complexes of technetium with pyrophosphate, etidronate, and medronate.

The reduction of [99Tc]pertechnetate was studied as a function of pH in complexing media of pyrophosphate, methylene diphosphonate (MDP), and ethane-1, hydroxy-1, and 1-diphosphonate (HEDP). Tast (sampled d-c) and normal-pulse polarography were used to study the reduction of pertechnetate, and normal-pulse polarography (sweeping in the anodic direction) to study the reoxidation of the products. Below pH 6 TcO4-was reduced to Tc(III), which could be reoxidized to Tc(IV). Above pH 10, TcO4-was reduced in two steps to Tc(V) and Tc(IV), each of which could be reoxidized to TcO4-. Between pH 6 and 10 the results differed according to the ligand present. In pyrophosphate and MDP, TcO4- was reduced in two steps to Tc(IV) and Tc(III); Tc(III) could be reoxidized in two steps to Tc(IV) and TcO4-. In HEDP, on the other hand, TcO4- was reduced in two steps to Tc(V) and Tc(III), and could be reoxidized to Tc(IV) and TcO4-. Additional waves were observed; they apparently led to unstable products.

Diphosphates↗
PubMed1978

Acute response to acid-base stress.

A method previously established in the experimental animal for predicting the acute response to either metabolic stress (bicarbonate administration) or respiratory stress(manipulation of oxygenator gas during cardiopulmonary bypass) has been extended to man. The method is based on a single nomogram. The accuracy of the nomogram is demonstrated using data from 13 patients on cardiopulmonary bypass. Similar agreement obtains between the nomogram and data reported by others. The nomogram can be used to estimate the therapeutically required dose of bicarbonate.

Acid-Base Imbalance↗
PubMed1978

Technique of scanning for Meckel's diverticulum.

99mTc-pertechnetate scanning is now recognized as a useful means of detecting Meckel's diverticula. When these contain gastric mucosa and present with ulceration and bleeding, the ectopic gastric mucosa can be identified by its secretion of 99mTc-pertechnetate. However, the secretions of normal gastric and salivary glands can pool in the gut and simulate a Meckel's diverticulum. We believe the diagnostic procedure of choice to include both continuous nasogastric suction and continuous sequential gamma camera images. To support this view, we present cases illustrating 1) that 99mTc-pertechnetate can appear in the bowel within the first few minutes of administering 99mTc-pertechnetate, even in the absence of a Meckel's diverticulum; 2) that rapid sequential camera views are helpful but not definitive in distinguishing such bowel activity from a Meckel's diverticulum; and 3) that continuous nasogastric suction most successfully eliminates this interference.

Adult↗