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PubMed1977

[Study of distribution of 203Hg-chlormerodrin, 203Hg-nitrate and 99mTc-DMSA in kidney by macroautoradiography (author's transl)].

Serial macroautoradiograms were obtained to determine the distribution of 203Hg-chlormerodrin, 203Hg-nigrate and 99mTc-DMSA in kidney. In the study, normal rats were used and these three radiopharmaceuticals were injected intravenously. Initial images of 203Hg-chlormerodrin showed the accumulation in the outer cortex, but no significant radioactivity in the medullary. On the other hand, delayed images revealed radioactivity shifting in concentration from the outer cortex to the inner cortex. Distribution pattern of 203Hg-nitrate was similar to that of 203Hg-chlormerodrin. In contrast to 203Hg-chlormerodrin and 203Hg-nitrate, 99mTc-DMSA was retained in the outer cortex without temporal changes in the distribution.

Animals↗
PubMed1979

Antimicrobial activity of chlormerodrin.

A radiochemical study for antimicrobial activity of chlormerodrin was performed using some commonly occurring nonpathogenic and pathogenic microorganisms. Chlormerodrin concentrations of 15-35 and 20-45 microgram/ml of the culture medium were microbiostatic and microbicidal, respectively. The microbiostatic effect was reversible in the presence of cysteine, an amino acid containing a sulfhydryl group.

Anti-Infective Agents↗
PubMed1977

Determination of extraction fraction by a double-tracer method.

A relatively simple dual-tracer method for measuring renal extraction fraction was compared with the direct method. In the dual-tracer method an extracted and nonextracted tracer are mixed together and administered into the arterial circuit and samples of venous blood are obtained. The ratio of recovered to injected tracer then determines the extraction fraction. In the direct method tracer is administered directly into the renal artery and the total venous effluent is collected. Extraction fraction is then calculated as arteriovenous difference divided by the quantity injected. In our experiments the extraction for 201Tl and 203Hg-chlormerodrin were determined. The extraction fraction for 201Tl averaged 81 +/- 5% by the direct method and 81 +/- 6% by the dual-tracer technique (r = 0.94). The extraction fraction for 203Hg-chlormerodrin was found to change as a function of the renal blood flow. At normal flow the extraction fraction averaged 48% by the direct method and 45% by the dual-tracer technique. At reduced flow, in contrast, it averaged 78% by the direct method and 71% by the dual-tracer technique.

Animals↗
PubMed1976

Triple isotope scintiphotography for differentiating between renal cysts and renal tumors.

As a routine diagnostic approach to patients who present hematuria or abnormal findings in X-ray films such as intravenous pyelograms, the cases are submitted to serial scintiphotography every two minutes after the intravenous administration of 250 muCi of 131I-Hippuran and to renography with PHO/GAMMA Scintillation Camera (Nuclear-Chicago). When scintiphotography with 131I-Hippuran reveals filling defect in the kidney region, scintiphotography with 150 muCi of 203Hg-chlormerodrin and renal blood flow scintiphotography after antecubital intravenous injection of 10 mCi of 99mTc are carried out. The present report concerns 8 cases of renal tumor and 5 cases of renal cyst confirmed by X-ray examination and surgical operation. The scintiphotography revealed decreased uptake of 131I-Hippuran and 203Hg-chlormerodrin in both tumor and cyst sites, exhibiting round or band-shaped filling defects. On the other hand, renal blood flow scintiphotography with 99mTc demonstrated the cyst as a filling defect but failed to visualize most of tumors. Accordingly, these techniques are available for differential diagnosis of the two lesions.

Adult↗
PubMed1977

Renal tubular handling of drugs.

The renal excretion of drugs is a vectorial quantity, the resultant of physiologic mechanisms that have directional orientation and magnitude. Magnitude is limited by a variety of extrarenal factors including plasma protein binding and the volume of the total body water. The contributions of the glomeruli and tubules to excretion varies with age. This fact has clinical relevance, especially in newborn children and older patients. Although protein binding reduces the amount of a drug that can be filtered, it usually does not alter the rate of proximal tubular secretion of charged organic molecules. Reabsorption of the filtered fluid from tubular lumens creates concentration gradients favoring the reabsorption of drugs, but the movement of drug molecules out of luminal fluid is hindered by the formation of polar drug metabolites in the liver. Although there are only a few examples in the literature, it is probable that many drugs are reabsorbed by a carrier-mediated process located in the proximal tubules. A major difference exists between the renal handling of chlormerodrin, a neutral mercurial, and of mersalyl, an acidic mercurial. Chlormerodrin is reabsorbed (as a complex with cysteine) by a carrier-mediated process; mersalyl is secreted by one of the organic anion transport systems.

Absorption↗
PubMed1975

Effect of diuretics on oxidative phosphorylation of dog kidney mitochondria.

An effect of diuretics on cellular metabolism has been shown. In order to examine further the direct effect of diuretics on renal mitochondria, their effect on isolated cortical (C) and outer medullary (OM) mitochondrial respiration was examined. Oxygen consumption rate (QO2) was measured in a Gilson oxygraph utilizing either glutamate-malate or succinate as substrate. QO2, expressed in nanoatoms of O2 per milligram of protein per minute, was always higher in C than OM: 140.7 +/- 2.8 VS. 121.2 +/- 2.4 (P less than 0.001) with glutamate-malate and 181.1 +/- 6.3 vs. 129.7 +/- 5.2 (P less than 0.001) with succinate. A dose-response curve was constructed for each of the following: sodium ethacrynate, furosemide, chlorothiazide, acetazolamide and chlormerodrin. All diuretics inhibited C and OM equally. The 50% inhibitory molar concentration for EA was 6.2 times 10(-4); for furosemide 1.5 times 10(-3); for chlorothiazide 8.1 times 10(-3); for acetazolamide 10.8 times 10(-3); and for chlomerodrin 3.1 times 10(-5). Neither cysteine nor dithiothreitol inhibited the effect of EA. The effect of chlormerodrin was abolished by cysteine. These results demonstrate that while a difference exists between C and OM mitochondria during control studies, each of the diuretics examined exerted an equal inhibitory effect on mitochondrial respiration from both C and OM. Mercurials are the most potent inhibitors and presumably exert their effect by reacting with sulfhydryl groups. They are followed in potency by ethacrynic acid, furosemide, chlorothiazide and acetazolamide.

Animals↗
PubMed1975

Tumour imaging radiopharmaceuticals.

32P, 131I-labeleed human serum albumin, 75Se-seleno-methionine, 107Hg-chlormerodrin, 67Ga-citrate and labelled bleomycin compounds, among others are discussed with particular respect to their observed clinical characteristics and suggested mechanisms of uptake. It is shown that there are striking similarities in the kinds of tumours demonstrable by these agents and that all of them may be taken up into inflammatory exudates. It is suggested that, while differences in the metabolism of each agent clearly exist, their mechanism of tumour uptake may be predominantly non-specific. It is concluded that radionuclide tumour imaging is of potential value mainly from the point of view of ease of whole body scanning for follow-up purposes and whereas other diagnostic methods may be more accurate in specific areas, ease of whole body screening is rarely a feature of these techniques. Methods for studying human cancer are necessarily restricted and the tumour imaging technique provides a unique, dynamic means of tumour observation. From the clinical point of view, the questions of why some tumours image well and others do not, what is the effect of treatment on uptake and how specific is the technique, are of most importance. In order to improve tumour imanging, more emphasis must be given to improving the lesion: background radioactivity ratio of the agents rather than attempting to improve detection equipment.

Animals↗
PubMed1975

Comparison of 99mTc complexes for renal imaging.

The distribution of 17 different agents for renal imaging was compared in the rabbit by organ radioassay at 1 hr. Similarly, 99mTc complexes of iron-ascorbate, glucoheptonate (GHA) and 2,3-dimercaptosuccinic acid (DMS), and 203Hg-chlormerodrin were compared in the dog. The distribution of 99mTc-GHA and DMS was assessed in the human by blood and urinary clearance, external renal measurements, and scintillation camera imaging, and compared with older renal radiopharmaceuticals. Radiation dose estimates, based chiefly on human data, were calculated. Technetium-99m-DMS reaches a high concentration in the renal cortex and its urinary excretion rate and blood clearance are slow. It is excellent for imaging the renal parenchyma without activity in pelvocalyceal collecting system. However, it readily oxidizes and must be used within 30 min of preparation. The biologic distribution of 99mTc-GHA is similar to gluconate and iron-ascorbate complex. Its renal concentration is not as great as that of DMS but its blood and urinary clearances are much faster, resulting in lower radiation doses to most organs. Early camera images with this agent usually demonstrate both the renal parenchyma and collecting system. In later images, ther is excellent demonstration of the parenchyma alone, superior to that obtained with 99mTc-Sn-DTPA. It is a very stable complex and may be used for at least 5 hr after preparation. All radioactive renal agents examined to date have a significant concentration in the liver, making an accurate quantitative comparison between the two kidneys difficult.

Albumins↗
PubMed1975

[Experimental investigations on the accumulation of radioactive compounds in autochtonal tumors in the rat (author's transl)].

For the first time results of investigations on rats with radioactive compounds in autochtonal tumors of the central nervous system, induced via placenta by Ethyl-Nitrose-Urea (ENU), are reported. In contrast to transplantation tumors the tumors induced by ENU are comparable in regard to the szintigrafic results with human brain tumors. The radiopharmaceuticals 131I-HSA, 99mTc-Pertechnetate, 203Hg-Chlormerodrin and 113m/111In-DTPA are similar to human brain tumors taken up by the ENU-tumors. For these findings it may be important, that the ENU-tumors are of neurogenic origin and do not differ histologically from the human brain tumors. The accumulation of the radioactive substances in ENU-tumors can be explained with the lesion at the blood-brain-barrier and at the blood-nerv-barrier. Therefore, it is discussed that the mechanism of the uptake is similar in human brain neoplasms and in ENU-tumors of the brain. The ENU-tumor model is suitable for testing new radiopharmaceuticals before their application in men.

Animals↗
PubMed1979

Computer-assisted static/dynamic renal imaging: a screening test for renovascular hypertension?

Computer-assisted static/dynamic renal imaging with [197Hg] chlormerodrin and [99mTc]pertechnetate was evaluated prospectively as a screening test for renovascular hypertension. Results are reported for 51 patients: 33 with benign essential hypertension and 18 with renovascular hypertension, and for 21 normal controls. All patients underwent renal arteriography. Patients with significant obesity, renal insufficiency, or renoparenchymal disease were excluded from this study. Independent visual analyses of renal gamma images and time-activity transit curves identified 17 of the 18 patients with renovascular hypertension; one study was equivocal. There were five equivocal and three false-positive results in the essential hypertension and normal controls groups. The sensitivity of the method was 94% and the specificity 85%. Since the prevalence of the renovascular subset of hypertension is approximately 5%, the predictive value is only 25%. Inclusion of computer-generated data did not improve this result. Accordingly, this method is not recommended as a primary screening test for renovascular hypertension.

Adult↗