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Biomedical subjects

S J Gibbs

Publications and source records attributed to S J Gibbs.

At least 55 records · Page 3Linked to original sources

Antidotes for gold (sodium bis[thiosulfato]gold[I]) intoxication in mice.

Eight compounds were examined to determine their relative efficacy as antidotes in acute gold intoxication in mice after the intraperitoneal injection of 200 mg/kg of Na3 [Au(S2O3)2] X 2H2O. Of the compounds examined, 2,3 dimercaptosuccinic acid was the most effective antidote. It was noted that with D-penicillamine those animals which did not survive died sooner (in a matter of hours) than the corresponding control animals which had received no antidote (about 3 days). In subsequent experiments in which Na3 [Au(S2O3)2] X 2H2O was administered at the lower level of 140 mg/kg, 2,3 dimercaptosuccinic acid showed itself to be capable of reducing kidney gold levels by a factor of about 5 and liver gold levels by a factor of approximately 2.

Animals↗

Patient risk from interproximal radiography.

Computer simulation methods for determining patient dose from dental radiography have demonstrated that patient risk from a two-film interproximal examination ranges from 1.1 X 10(-8) to 3.4 X 10(-7) using 90-kVp beams, depending on film speed, projection technique, and age and sex of the patient. Further, changing from a short-cone round-beam to a long-cone technique with rectangular collimation reduces risk by a factor of 2.9, independent of other factors.

Adolescent↗

Intravascular contrast agents suitable for magnetic resonance imaging.

Two paramagnetic chelates, chromium EDTA and gadolinium DTPA, were evaluated as potential intravenous contrast agents for magnetic resonance imaging (MR) using a 0.5-T superconducting scanner. After evaluating both agents in vitro, in vivo studies were conducted in dogs to document changes in renal appearance produced by contrast injection. Acute splenic and renal infarction were diagnosed with contrast-enhanced MR and confirmed by gamma camera imaging following administration of Tc-99m-labeled DMSA and sulfur colloid. The authors conclude that intravenous paramagnetic contrast agents presently offer the best mechanism for assessment of tissue function and changes in perfusion with MR.

Animals↗

Ethylenediaminetetra(methylenephosphonic) acid (EDTPO) as a therapeutic chelating agent.

Ethylenediaminetetra(methylenephosphonic) acid (EDTPO), when administered as its calcium salt, is an effective antidote for acute intoxication by a number of metal ions. Significant antidotal action was found for the following cations: Cd2+, Ni2+, Zn2+, Pb2+, Be2+ and UO2+(2). Because EDTPO is capable of chelating more than one calcium ion, better results were obtained when the Ca2EDTPO complex was administered.

Animals↗

Radiographic techniques to evaluate paintings.

Radiographic techniques may be helpful in evaluation of the condition of paintings for their restoration, preservation, and occasionally to determine their authenticity. On the basis of experience with several of these procedures, the utility of each method is described in reference to specific "diagnoses" regarding paintings. Radiographic techniques have several advantages over other methods; they are nondestructive, they may be used to survey the entire painting, and they are subject to quantitative and serial analysis.

Art↗

Biological effects of radiation from dental radiography. Council on Dental Materials, Instruments, and Equipment.

Clearly, there is ample evidence of adverse effects of radiation in sufficient doses. There is at present no proof of such effects from doses commonly employed in dental practice; however, it has not been possible to prove the absence of such effects. Most experts now agree that there may be a small, difficult to quantify risk of cancer or genetic mutation from diagnostic exposure in patients and in personnel exposed during work. Prudence dictates acceptance of this position until proof to the contrary is available. This report has presented recent attempts to quantify the risk to patients based on speculative calculations and extrapolations. Indices of population risks indicate that medical radiology is the largest source of human-made genetic and leukemogenic radiation burden to the American public. Dental radiology contributes a small-but not necessarily insignificant-portion. Of major concern is the increasing use of radiation for diagnostic purposes in both medicine and dentistry. Technological advances have reduced exposure per examination; presumably this trend will continue so that total exposure of populations to radiation in the healing arts will not increase. Recent analyses suggest that the cancer risk to a patient from a dental radiographic examination is of the order of one in a million; the genetic risk is substantially less, about one in a billion. The risks appear to be essentially equal for full-mouth intraoral and for panoramic examinations. These estimates are numerically quite small, but the effects are severe. Thus, these risks cannot be ignored. However, we currently accept risks of similar magnitude in our daily lives [Table 9]50,51 In addition, the risk of failure to make an accurate diagnosis may be greater than the risk from exposure to the radiation from a justified and properly conducted radiographic examination. It therefore appears reasonable that the information gained from a justified and properly conducted radiographic examination outweighs the risk.

Adult↗

A comparison of diethyldithiocarbamate and EDTA as antidotes for acute cadmium intoxication.

For mice which have been given the cadmium equivalent of CdCl2 X 2 1/2H2O at a level of 10 mg/kg, diethyldithiocarbamate (DDTC) administration at 500 mg/kg leads to a higher survival rate than is found with Na2CaEDTA under identical conditions. This occurs when the interval between administration of the cadmium salt and the antidote is either one or two hours. The surviving animals, however, are found to have appreciable levels of cadmium in their brain, liver and kidney when they were treated with DDTC, though their behavior appeared to be normal. The use of 50 mg/kg of DDTC after 2 hr in such cadmium poisoned mice also leads to a higher survival rate and reduced amounts of cadmium retained in the brain, liver and kidney. Unlike the other chelating agents which have been reported as useful in acute cadmium intoxication, DDTC appears to act by forming a lipid soluble complex which is largely immobilized in lipid containing tissues of the animal's body.

Acute Disease↗