CLINICAL APPLICATION OF PATLAK PLOT CT‐GFR IN ANIMALS WITH UPPER URINARY TRACT DISEASE

Glomerular filtration rate (GFR), an important parameter of renal function, is difficult to assess clinically. Serum creatinine and blood urea nitrogen measurements lack sensitivity, whereas radionuclide determination of GFR is not always available and requires postinjection patient isolation. GFR can be determined using computed tomography (CT), most commonly via Patlak plot analysis. Four adult cats, two adult dogs, and a foal underwent abdominal CT under general anesthesia for various diseases of the upper urinary tract. CT‐GFR was measured with a single‐slice dynamic acquisition and Patlak plot analysis. In five animals, the total CT‐GFR appeared to be below normal, corresponding with mild (two animals) and moderate (two animals) increases of serum creatinine in four. In the two animals with normal or increased CT‐GFR, serum creatinine was within the reference values. A significant negative logarithmic relationship was found between CT‐GFR and serum creatinine values (P=0.008; r²=0.75). No complications occurred during or following CT‐GFR. CT examination provided clinically relevant information in 3/5 patients with possible ureteral obstruction and in 3/3 patients with suspected ureteral calculi. Single‐slice dynamic CT‐GFR was practical and provided clinically useful information in this small series of patients undergoing CT of the upper urinary tract. There was a significant relationship between CT‐GFR and serum creatinine values, which supports the clinical potential of CT‐GFR and justifies further investigation of this technique.     

Short‐scale distribution of copper fractions in a vineyard acid soil

We studied short‐scale variation in the total concentration of copper and its fractions in a soil vineyard. Soil samples were collected at a depth of 0–20 cm between plant rows (1), between individual plants (2) and at their base (3) in a vine‐grown plot in NW Spain. The mean total content in Cu (Cu_t) in the soil was found to be 97 mg kg⁻¹ and that of potentially available Cu (Cu_EDTA) 34 mg kg⁻¹. Copper bound to organic matter (Cu_OM) and to non‐crystalline inorganic soil components (Cu_IA) were the dominant fractions and accounted for 34% of total copper each. The contents in exchangeable (Cu_e), pyrophosphate‐extractable (Cu_p), oxalic/oxalate‐extractable (Cu_o) and total copper (Cu_t) exhibited statistically significant correlations with pH, sum of base cations (S), cation‐exchange capacity (CEC) and exchangeable calcium (Ca_e). Both total and fractional copper contents were higher in plant rows than between them, particularly in the centre of the plot. Also, Cu_OM and Cu_IA were higher in planting rows than between rows. These copper results may have been influenced by the vine‐growing practices of the area and also by the distribution of plants and their pruning. This variability pattern for Cu distribution is crucial with a view to minimising potential adverse effects of fungicides and optimising any reclamation treatments needed. Copyright © 2007 John Wiley & Sons, Ltd.     

Ultrastructural Study of the Early Development of the Sheep Embryo

An ultrastructural study of the different stages of pre-implantation in sheep was carried out, analysing the changes brought about mainly in the morula and blastocyst stages. The analysis of the embryos obtained showed a series of common characteristics in all stages, most noticeable being the presence of a high number of vesicles distributed in a uniform way in the cytoplasm, and also the presence of numerous electron-dense mitochondria in many varied forms. The most important ultrastructural modifications took place at the 16-cell stage and affected, principally, the nucleus, which presented numerous condensations of chromatin distributed along the nucleoplasm. The nucleoli adopted a reticular morphology, abandoning the compact aspects presented in the previous stage. These changes might be involved in the synthesis of embryonic RNA, and, accordingly, in the activation of the genome of this species. These data indicate that this stage is critical to the embryonic development and might be related to the blockage produced in the development of cultivated sheep embryos at the point of transition from 8 to 16 cells. Nevertheless, it should be pointed out that the first signs of modifications in the aspect of the nucleus are observed at the four-cell stage, being characterized by the appearance of vacuolated areas in the nucleolus, indicating the first signs of embryonic nucleic activity, which would anticipate the main change in the control of the protein synthesis.     

Comparison of worm control strategies in grazing sheep in Denmark.

Control of nematode parasites with reduced reliance on the use of anthelmintics was studied in 16 ewes with suckling twin lambs on contaminated pasture in Denmark. Ewes and lambs were treated with albendazole at turn-out 3 May. Ewes were removed from the groups on 26 July, and lambs were slaughtered on 11 October. The animals were allocated to 4 groups of 8 lambs and their 4 ewes. Group TS was treated with albendazole at weeks 3, 6 and 8 after turnout and set-stocked; group TM was similarly treated but moved to clean pasture in conjunction with the last drenching; group US was untreated and set-stocked, and group UM was left untreated but moved to clean pasture week 8 after turn-out. Supplementary feed was offered in June and August due to scarcity of pasture. Strategic treatments of ewes and lambs weeks 3, 6 and 8 after turn-out, with or without a move to clean pasture, were highly effective in controlling nematode infections for most of the season. This was reflected in better weight gains and carcass characteristics in the treated compared to untreated lambs, resulting in an average increase in the value of the product by 36%. The effect of moving without treatment (UM) on faecal egg counts was limited but peak pasture infectivity was reduced to less than 10% compared to the set-stocked group and weight gains of lambs were significantly better despite poor feed availability in late season. The study showed that under set-stocked conditions repeated anthelmintic treatments of both ewes and lambs in early season may ensure sufficient nematode control whereas moving animals to clean pasture without dosing was less efficient. The latter may, however, still be a viable option in organic and other production systems where routine use of anthelmintics is banned, particularly if weaning and moving are combined or a second move is performed.     

Pseudomonas Fluorescens UP61 Isolated From Birdsfoot Trefoil Rhizosphere Produces Multiple Antibiotics and Exerts a Broad Spectrum of Biocontrol Activity

The efficient use of rhizospheric microorganisms to control plant pathogens has been reported worldwide in different plants. Pseudomonas fluorescens UP61 is a biocontrol strain isolated from the rhizosphere of Lotus corniculatus(birdsfoot trefoil) from Uruguayan soils. This strain exhibited in vitro antagonistic activity against a broad spectrum of fungal and bacterial phytopathogens. It was an effective biocontrol agent in different hosts, reducing the disease incidence caused by Sclerotium rolfsii in beans and Rhizoctonia solani in tomato. P. fluorescens UP61 produced three antibiotics possibly involved in its biocontrol activity: 2,4-diacetylphloroglucinol, pyrrolnitrin and pyoluteorin. Molecular techniques such as 16S rDNA RFLP, RAPD and rep-PCR, and partial sequence of the phlD gene, revealed the similarity of UP61 with other biocontrol strains isolated worldwide that are able to produce these antibiotics.     

Flavobacterium columnare genomovar influences mortality in channel catfish (Ictalurus punctatus)

Flavobacterium columnare, causal agent of columnaris disease, is pathogenic to many species of freshwater fish throughout the world. The United States channel catfish (Ictalurus punctatus) aquaculture industry is severely impacted by columnaris disease. The majority of the F. columnare isolates recovered from diseased channel catfish belonged to either genomovars I or II. The objective of the present study was to determine if differences existed in the ability of these genomovars to induce mortality in channel catfish. Single strand conformation polymorphism analysis (SSCP) was used to ascribe the isolates used in this study to the appropriate genomovar. Immersion challenge experiments (15min immersion exposure to approximately 5x10(5) to 1x10(6) CFU/mL) were carried out to assess virulence of genomovar I and II isolates to channel catfish. The results demonstrated that genomovar II (n=4) isolates were significantly (P<0.05) more virulent to channel catfish fry (92-100% mortality) than genomovar I (n=3) isolates (0-46% mortality). In vivo adhesion of the genetically characterized F. columnare also correlated (r2=0.73) to increased mortality in the challenged fry. In fingerling channel catfish, significantly higher mortality (P<0.05) resulted with genomovar II isolates ALM-05-182 and ALG-00-530 as compared to all the genomovar I isolates (n=3). Mortality of genomovar II isolate BGFS-27 with similar to genomovar II isolate (ALG-00-530) and two genomovar I isolates (ALM-05-53 and 140). The results suggest that although both genomovars are present in the aquatic environment, genomovar II appears to be more pathogenic for channel catfish.