THE EFFECT OF PATIENT POSITIONING ON MURAL FILLING DEFECTS DURING DOUBLE CONTRAST CYSTOGRAPHY

Different radiographic findings may be observed during double contrast cystography due to patient positioning affecting the distribution of positive and negative contrast media. A mass lesion was created in the urinary bladder of a canine cadaver to allow evaluation of the effect of patient positioning on the appearance of a mass during double contrast cystography. The mass appeared as a filling defect only on those views where positive contrast medium surrounded the mass. Otherwise, the mass appeared as a summation. Additionally, a patient is described illustrating the effect of patient positioning on detecting mural filling defects during double contrast cystography.     

Biotest— and chemistry-based hazard assessment of soils,sediments and solid wastes

Background and Objectives  The current environmental legislation regulating pollution issues is based on total levels of pollutants. This approach is not taking into account the bioavailability of pollutants (that is especially important for an analysis of soils and sediments as heavy metals and hydrophobic organic toxicants tend to sorb to solid matrix) and effects of toxicants in mixtures. Thus, toxicity-based criteria should be added to the currently existing chemical ones for the meaningful evaluation of the environmental hazard. The aim of the current study was 1) to compare the ecotoxicity and chemistry-based environmental evaluations for 27 solid-phase environmental samples (soils, sediments, solid wastes); 2) to suggest the battery of biotests for the screening of water-extracted toxicity. Methods  14 soils, 9 sediments and 4 oil-shale industry solid waste samples from Estonia and Lithuania were analyzed for the concentration of total PAHs, heavy metals, oil products and water-extracted phenols. The pollution level was evaluated by comparison of measured concentrations with Estonian permitted limit values in residential (PLV_r) and industrial (PLV_i) areas for each key pollutant A battery of 8 aquatic toxicity tests was applied for the analysis of aqueous extracts (L/S=3) of samples: tests with microalgaeSelenastrum capricornutum, macroalgaeNitellopsis obtusa, protozoaTetrahymena thermophila, crustaceansDaphnia magna andThamnocephalus platyurus, rotifersBrachionus calyciflorus and photobacteriaVibrio fiscberi. Particle-bound bioavailable toxicity was evaluated using a kinetic photobacterial assay withVibrio fiscberi (Solid-Phase Flash-Assay). The toxicity data were evaluated by MaxTox index (highest toxic signal of the battery). Results  Chemical evaluation and toxicological evaluation pointed to the same direction in half of the cases (13/27): 5 samples (including 2 presumably clean control soils) proved harmless and 8 hazardous to environment in case of both evaluations. However, there was a disagreement between chemical and toxicological evaluations for the rest of the samples (14/27). In two mismatching cases (soils from the territory of former gasoline stations) the level of oil products exceeded the PLV_r, but no toxicity was detected, most probably due to the low bioavailability of aged pollutants. It must be taken as a warning that a majority of mismatching cases (12/14) of the samples proved to be toxic or even very toxic despite the fact that the measured hazardous key pollutant levels were below the PLVr. Within these 12 samples were 2 soils from municipal dumping sites, 2 soils from the territory of military airport, 6 sediments from Curonian lagoon (Lithuania) and 2 oil-shale industry solid wastes (Estonia). Conclusions  The results of this study show the necessity of biotesting in environmental risk assessment to avoid the falsenegative results that may result in harmful effects for the ecosystems and also to human health. The following, reduced test battery was proposed for the ecotoxicological hazard assessment of water-extractable toxicity of solid-phase samples:Tetrahymena thermophila growth inhibition assay,Daphnia magna mortality assay andSelenastrum capricornutum growth inhibition assay. Also, the Microtox test (Vibrio fiscberi luminescence inhibition assay) could be valuable for screening purposes. For the evaluation of particle-bound, bioavailable toxicity of soil suspensions, Solid-Phase Flash-Assay (test organismVibrio fiscberi) is suggested. Compared to the results obtained with the initial battery of 8 tests, the reduced battery detected the toxicity in 85% of the cases.     

Properties of humic substances from the baltic sea and lake ermistu mud

Scope and Goal  Humic substances (HSs) are the product of microbial degradation, chemical polymerisation and oxidation of organic matter. HSs can be divided into different fractions: humic acid (HA), hymatomelanic acid (HMA), fulvic acid (FA) and humin. HSs play a fundamental role in accumulation and exchange processes of chemical compounds (metals and organic pollutants) in the environment. HSs can form soluble complexes that migrate long distances or precipitate, carrying bound cations with them. The migration/precipitation abilities depend on the metal ion, the ion charge, the degree of ionisation of the organic molecule, the ionic strength of the media, and the location of the metal ion. Objective  Estonia is rich in the Baltic Sea and lake sediments. Historically, mud has been used in human treatment as a curative mud. High-molecular HSs are an important part of curative mud and they have a strong effect on its properties. The curative mud which is used in human therapy may not be polluted with different organic and inorganic contaminants. The aim of this work is to characterise and compare HSs isolated from the Baltic Sea mud (Haapsalu Bay) and from the sediments of Lake Ermistu (Estonia). Results and Conclusions  We determined the yield of basic extraction of different HSs components from mud in the course of separation. We found that acid pre-treatment of mud increased the amount of extracted HSs more in the sea mud than in the lake mud. These results show that HSs are bound to the inorganic/organic structure of mud and are released during prolonged treatment with an acid. We performed elemental analysis of the different fractions of HS extracts. HMA fractions had the highest carbon content and the lowest nitrogen content. HMA contains more polysaccharides than amino acid residues. These subunits may cause a better solubility of HMA in water as compared to HA. Acid pre-treatment of the natural sea and the lake mud diminished the content of carbon in most of the HS fractions. The content of nitrogen in the sea and in lake FA diminished by about two times. We determined the metal content in the mud and its HS fractions. We found that the concentration of heavy metals Pb and Cr is lower than <0.08 mg/kg. As expected, the total metal concentration is considerably lower in the lake than in the sea mud. Acid pre-treatment of mud shows that the sea HA forms more stable Fe and Mg complexes, while the sea HMA contains more stable Zn and Cu complexes. The lake HSs result in more stable Mg complexes with HA and HMA fractions. Sea FA binds Cu and Mg better, but lake FA is more effective in binding Zn. To compare the amount of metals extracted from HA, HMA, FA (with that, remains in HS fractions), the metal concentration in the alkaline full extract of the sea mud was determined. Alkaline treatment removed 0.8% Mg, 7.9% Cu, 5.2% Zn and 3.8% Fe together with HSs from the sea mud, the rest remained in humin and in the mineral part of the mud. The following work-up was additionally carried out for most of the metals. So, we found that there was only 1.7% of Fe, 2.1 % of Mg, 23.2% of Zn and 45.2% of Cu left in HA, HMA and the FA fraction (as a sum) from the total amount of those metals in HSs. This means that Cu is the metal most strongly bound to HSs. On the bases of HS separation data we found that the order of stability of the metal-humate complexes is Cu>Zn>Mg>Fe. The ultraviolet spectra of HA, HMA and FA revealed that HMA had the biggest molar absorption and calculated aromaticity. Recommendations and Outlook. The characteristics of HSs, isolated from the Baltic Sea and Lake Ermistu mud reveal the difference of HSs from the sea and the lake mud. Also, different properties of HS fractions are observed. Metals are concentrated variously in different HS fractions. In all cases the content of Pb and Cr was low, meaning that the mud preparations are nontoxic in respect to these metals. The order of stability of metal-humate complexes is Cu>Zn>Mg>Fe. The order of affinity of metals to HS fractions obtained have to be extended to other metals of environmental interest. The ability of HSs to bind metals may make them a candidate for natural, environmentally safe substances to concentrate hazardous metals and to remove them from natural water reservoirs.     

SUBDURAL INJECTION OF CONTRAST MEDIUM DURING CERVICAL MYELOGRAPHY

Three patients (1 dog, 2 horses) ae described where myelography was complicated, purportedly by injection of contrast medium into the meninges superficial to the subarachnoid space. Contrast medium injected in this locationin a cadaver tended ot accoumulate dorsally within the vertebarel canal, deep to the dura mate but superficial to the subarachnoid space. The ventral marginof the pooled contrast medium had a wavy or undulating margin and the dorsal margin was smooth. Pooled contrast medium was believed to be sequestered within the structurally weak dural border cell layer between the dura mater and arachnoid membrane, or so-called subdural space.