QUANTITATIVE HEPATOBILIARY SCINTIGRAPHY IN NORMAL CATS AND IN CATS WITH EXPERIMENTAL CHOLANGIOHEPATITIS

Quantitative hepatobiliary scintigraphy using 99mTc-mebrofenin was performed on eight normal cats and on the same cats after induction of experimental cholangiohepatitis by infection with the liver fluke Platynosomum concinnum. Hepatobiliary scintigraphy was performed 3 times at 10 weeks, 4 months and 6 months after infection. In addition, routine biochemical tests, hepatic ultrasound and ultrasound guided hepatic biopsy samples were obtained at the same time points, and the results compared with hepatobiliary scintigraphy. The normal hepatic extraction fraction was determined to be 85%, and the normal hepatic excretion half time (T 1/2) was 14 minutes. There was no significant change in scintigraphic parameters compared to pre-infection values at any time following infection with the liver fluke. No correlation between scintigraphic parameters and histologic scores was found; however, significant correlation was identified between parasite burden and histologic scores 6 months following infection. Despite the presence of severe multifocal histologic abnormalities, minimal clinical, biochemical and scintigraphic derangements were identified using this model of cholangiohepatitis. Based on this study, hepatobiliary scintigraphy appears to be an insensitive test for structural hepatobiliary abnormalities. The role of hepatobiliary scintigraphy in functional hepatobiliary abnormalities of the feline liver has not been determined.     

Evaluation of accumulation and concentration of heavy metals in different urban roadside soil types in Miranda Park,Sydney

Purpose

The overall objectives of this study were to examine the relationship between the concentrations of heavy metals such as Pb, Zn, Cu, and Cd in roadside soil derived from three different geological parent materials, Hawkesbury Sandstone, Wianamatta Shale, and Mittagong Formation and also to examine the influence of rainfall events on heavy metal concentrations in both the topsoil and the subsoil in all three soil types. In this paper, the focus is on lead and zinc.

Materials and methods

The results obtained from the samples taken from an initial transect were used to select the location of the study sites. Soil samples were collected using a stainless steel auger at distances of 1, 5, and 10 m from the edge of two major roads of similar traffic volumes bordering a suburban park. At each of five study sites, samples were collected at depths of 0–10 and 10–30 cm, three times pre-rainfall (after extended periods of no rain) and three times post-rainfall (after intensive rainfall periods). The modified aqua regia digestion method was applied for heavy metal concentrations measurement. To determine the temporal dynamics of trace elements in the soils, sequential extractions were applied to all the topsoil samples according to the modified three-step sequential extraction procedure.

Results and discussion

The corresponding concentrations of Pb and Zn were different for the soil derived from Hawkesbury Sandstone and Wianamatta Shale and also Mittagong Formation. The highest concentration of Pb was in the soil from Wianamatta Shale, 159.32 mg/kg and the highest concentration of Zn was in the soil from the Mittagong Formation, 254.12 mg/kg, all at a distance of 1 m from the roadside. From the sequential chemical extraction results, the rainfall substantially influenced the exchangeable fraction (F1) of Pb at a distance from the road of 1 m. A significant reduction of F1 was found for the soil derived from Mittagong Formation which also had the most significant reduction of total Zn concentration.

Conclusions

The interpretation of the results showed that there was a clear correlation between the concentration of Pb and Zn with the distance from the roadside and depth in all soil types. However, the results also showed that there are variable concentrations between the soil types. The heavy metal concentrations at the same distance for the three soil types are different. The rainfall events do influence the heavy metal concentration differently in both topsoil and subsoil of the three soil types at the same distance from the roadside.

     

Flunixin residues in milk after intravenous treatment of dairy cattle with (14)C-flunixin

Flunixin meglumine is used in veterinary medicine as an alternative to narcotic analgesics and as an antiinflammatory agent. Eight Holstein dairy cows were dosed intravenously once daily on three consecutive days with (14)C-flunixin meglumine at approximately 2.2 mg of flunixin free acid/kg of body weight. Milk was collected twice daily to determine the decline of the total radioactive residues (TRR) in milk and to identify or characterize residue components. TRR in milk declined rapidly and averaged 66, 20, and 14 ppb, respectively, for the first, second, and third milkings after administration of the last dose. Milk was extracted, and the extracts were examined for radioactive residues. Mean extractability of milk TRR was always greater than 80%. Flunixin and 5-hydroxyflunixin were identified by coelution with analytical standards using reverse phase HPLC. These two residues were the main radioactive residues found in milk and together accounted for 64, 37, and 44% of the extractable residues, for the first, second, and third milkings, respectively, after administration of the last dose. The presence of 5-OH flunixin in milk was confirmed by HPLC/MS/MS.     

A study of airborne metals in Calcasieu Parish,Louisiana using the lichens,Parmelia praesorediosa and Ramalina stenospora

Two common species of lichens from southwestern Louisiana, Parmelia praesorediosa and Ramalina stenospora, were analyzed thrice over a period of 9 mo. Samples were analyzed for Th, Cs, Se, Hg, Cr, Ir, Ce, Sc, Rb, Fe, Zn, Co, Ta, Eu, K, and Sb. No statistical differences in concentration over the time interval studied were seen. However, discriminant analysis showed a significant (>90%) difference between elemental content and species. The data could be separated into two geographical areas that were statistically different. Highest concentrations were observed within a 10.8-km radius of the industrial/urban zone.     

Nematode communities of grazed and ungrazed semi-natural steppe grasslands in Eastern Austria

Soil nematode communities were investigated at eight semi-natural steppe grasslands in the National Park Seewinkel, eastern Austria. Four sites were moderately grazed by horses, cattle and donkeys, four were ungrazed. Nematodes were sampled on four occasions from mineral soil, and their total abundance, diversity of genera, trophic structure and functional guilds were determined. Altogether 58 nematode genera inhabited the grasslands, with Acrobeloides, Anaplectus, Heterocephalobus, Prismatolaimus, Aphelenchoides, Aphelenchus, Tylenchus and Pratylenchus dominating. Mean total abundance at sites was 185–590 individuals per 100 g soil. Diversity indices did not separate communities well, but cluster analysis showed distinct site effects on nematode generic structure. Within feeding groups the relative proportion of bacterial-feeding nematodes was the highest, followed by the fungal- and plant-feeding group. Omnivores and predators occurred in low abundance. The maturity indices and plant parasite indices were characteristic for temperate grasslands, but the abundance of early colonizers (c-p 1 nematodes) was low. A high density of fungal-feeding c-p 2 families (Aphelenchoidae, Aphelenchoididae) resulted in remarkably high channel index values, suggesting that decomposition pathways are driven by fungi. Nematode community indices of all sites pointed towards a structured, non-enriched soil food web. At most sites, grazing showed little or no effect on nematode community parameters, but total abundance was higher at ungrazed areas. Significant differences in the percentage of omnivorous nematodes, the sum of the maturity index, the number of genera and Simpson's index of diversity were found at one long-term grazed pasture, and this site was also separated by multi-dimensional scaling (MDS).     

Mercury methylation by sulphate-reducing bacteria from sediments of an acid stressed lake

The role of freshwater sulphate-reducing bacteria in McHg production was examined by adding specific microbial inhibitors to anoxic lake sediments spiked with ²⁰³HgCl₂ and measuring net methylation. The effect of increased sulphate (such as would arise from acid deposition in the area) on the activity of sulphate-reducing bacteria both in terms of sulphate reduction rate and methylation of Hg was examined by adding sulphate to ²⁰³HgCl₂ spiked sediments. Sodium molybdate (10 mM), a specific inhibitor for sulphate-reducing bacteria, reduced the amount of MeHg produced from anoxic lake sediments by 75% compared with controls over a 7 d period. In contrast, 2-bromoethane sulfonic acid (15 mM), a specific inhibitor for methanogenic bacteria, did not alter the amount of McHg produced. Additions of sulphate that were “realistic” in terms of the normal range of the area (5 to 30 mg.L^?), increased the sulphate reduction rate of sediment slurries. However, in the experimental system, these additions did not stimulate McHg production. In our study, methylation of Hg in sediments was primarily due to the activity of sulphate-reducing bacteria. However, the methylation rate does not appear to be sensitive to the concentration of sulphate over the range typical of softwater, Precambrian Shield lakes. This could be due to reduced availability of Hg due to the formation of insoluble HgS or to the fact that the overall activity of sulphate reducers not being stimulated even if sulphate reduction rate is, or both.     

A preliminary study of the growth of fungi and bacteria from temperate and antarctic soils in relation to temperature

The growth of fungi isolated from a lowland temperate site (Roudsea Wood National Nature Reserve), an upland temperate moorland (Moor House National Nature Reserve) and an oceanic Antarctic island (Signy, S. Orkneys) was compared at 1, 14 and 25°C. This showed that low temperatures caused greatest retardation of growth in fungi from the warmest site (Roudsea) and least from the coldest site (Signy Island). At Moor House, fungi which were isolated most frequently in winter were able to grow better at 1°C than summer forms. The fungal flora of Signy Island was restricted and consists of cold tolerant cosmopolitan species which have been selected by or become adapted to the prevailing low temperatures. Of fungi isolated from any two of the sites, Mortierella alpina and Mucor hiemalis showed temperature adaptation correlated with prevailing site temperature, while Trichoderma viride, Penicillium thomii, and P. frequentans showed no adaptation.     

Effect of soil properties on the degradation of isoxaflutole and the sorption-desorption of isoxaflutole and its diketonitrile degradate

The transformation of isoxaflutole (ISOX) to its herbicidally active diketonitrile degradate (DKN) was significantly enhanced in the presence of soil and occurred more rapidly in systems containing soil with a greater soil pH. Sorption-desorption of ISOX and DKN in five soils collected within a field revealed both ISOX and DKN were more readily sorbed to soils with greater organic matter, clay content, and lower soil pH. Sorption of ISOX residues occurred within 2 h, and extracts contained similar concentrations of ISOX and DKN at 24 h, suggesting the 24-h sorption coefficients for ISOX-treated systems were actually for mixed ISOX residues. Freundlich sorption coefficients were 3 and 4 times greater for ISOX than for DKN. On the basis of the Freundlich organic carbon sorption constants, ISOX and DKN can be categorized in the very high and high mobility classes, suggesting their potential to leach in the soils needs to be evaluated.