RELEVANCE OF SONOGRAPHIC ARTIFACTS OBSERVED DURING IN VITRO CHARACTERIZATION OF UROCYSTOLITH MINERAL COMPOSITION

Nine pure mineral type canine uroliths (bladder or urethral origin only) were imaged ultrasonographically using 3.5 MHz, 5.0 MHz, and 7.5 MHz fixed focus, mechanical sector transducers in a urinary bladder phantom. The uroliths studied were those composed of 100% magnesium ammonium phosphate, calcium oxalate monohydrate, calcium oxalate dihydrate, calcium phosphate appatite, and calcium hydrogen phosphate dihydrate (brushite), ammonium acid urate, sodium acid urate, cystine, and silica. The occurrence of both reverberation/streak and acoustic shadowing artifacts were compared to urocystolith mineral type (classified by effective atomic number), urocystolith width, urocystolith height (thickness), and ultrasonographic imaging frequency. No predictable relationship was found between either of the artifacts seen beyond the urocystolith (reverberation/streak or the acoustic shadowing) and urocystolith mineral type. There was no statistical relationship between the occurrence of reverberation/streak artifact and the size (width or height) of the urocystolith or the ultrasonographic frequency. There was, however, a statistically relevant relationship between ultrasonographic imaging frequency and the occurrence of acoustic shadowing and between urocystolith height (thickness) and the occurrence of acoustic shadowing. However, regardless of ultrasound frequency, acoustic shadowing was observed less than 35% of the time in any of the urocystolith mineral types examined. Based on the imaging of the bladder phantom supporting apparatus (7.0 mm bolts covered by plastic), the accurate characterization of a curved object surface directly facing the transducer was found to be directly related to the frequency of sound used for imaging and at best predictably limited to curved vs flat. Accurate measurement of the maximum transverse dimension of an echogenic curved object or accurate characterization of the lateral borders of such an object was considered unlikely with general ultrasonographic equipment of the frequencies studied. Therefore, detailed architectural characterization of urocystoliths suitable for mineral composition prediction is considered highly unlikely with general pulse-echo ultrasonographic techniques.     

Evaluation of the possibilities of using humic acids obtained from lignite in the production of commercial fertilizers

Purpose

Technological progress and high market demand contributed to a significant interest in the production of fertilizers based on humic acids. The aim of this study was to evaluate the possibilities of using humic acids obtained from lignite in the production of new commercial products. For this purpose, it is necessary to determine the quality standard requirements for such material. Properties of humic acids depend on source of origin as well as method of its extraction.

Materials and methods

The humic acids were extracted from polish deposit of lignite–Sieniawa Lubuska by alkaline extraction using for this purpose six kinds of extractants: 0.1 M NaOH and 0.25 M NaOH, 0.1 M KOH and 0.25 M KOH, and 0.1 M Na₄P₂O₇ and 0.25 M Na₄P₂O₇. The humic samples were used in solid powder form and characterized by UV-Vis spectroscopy, ¹³C NMR spectroscopy, fluorescence spectroscopy, and thermal analysis.

Results and discussion

The determining factor influencing a degree of humic acids extraction from lignite and their structure is type of extractant. The largest efficiency of extraction (about 50%) was obtained with the use of NaOH solutions. All examined humic acids were generally characterized by simple and heterogeneous molecularly structure with low molecular weight and low aromatic polycondensation. Therefore, it can be concluded that humic acids extracted with NaOH and KOH solutions are less condensed than those extracted with Na₄P₂O₇ solutions. It can suggest that humic acids obtained from lignite using solutions of Na₄P₂O₇ are characterized by a low transformation degree and greater amount of carboxyl groups.

Conclusions

Low rank coal can be successfully used in agriculture as a rich source of humic acids. Reagent used in their extraction, apart from high efficiency should have a neutral impact on their structure. Studies on the physicochemical properties of humic acids can be helpful in predicting behaviors of such fertilizer components in the environment and in inventing new products taking the principles of sustainable development into consideration.

     

The energy metabolism of growing swine in the body weight range of 10-50 kg. 2. Nitrogen and energy metabolism

Investigations were carried out about nitrogen and energy metabolism feeding rations with 17-24 and 44-47% crude protein content on maintenance and growing level to castrated male hybrid pigs of line 150. In growing periods the N deposition amounted to 10 g/animal.d (15 kg live weight), 18 g/animal.d (30 kg LW) and 21 g/animal.d (greater than 40 kg LW) on lower protein feeding level. In experiments with higher protein feeding level the corresponding results were 17, 22 and 22 g N deposition/animal.d. The partial utilization of metabolizable energy for deposition amounted to 70% for the rations with 17-24% protein content and to 59% for the rations with 44-47% protein content, without correlation to the animals development and the alternation in the protein feeding level. The results of regression analysis about maintenance requirement were 814, 775 and 806 kJ metabolizable energy/kg LW0.62.d in trials feeding rations with 17-24% crude protein content as well as 764, 846 and 818 kJ metabolizable energy/kg LW0,62.d in trials feeding rations with 44-47% crude protein content. 1,5-1,8 MJ metabolizable energy were used per MJ protein energy deposition and 1,3-1,4 MJ per MJ fat energy deposition respectively. The energy deposition per kg live weight gain amounted to values between 9 (10 kg LW) and 18 MJ (60 kg LW).     

Diversity and structure of regenerating tropical dry forests in Costa Rica: Geographic patterns and environmental drivers

Much of the dry tropical forest biome has been converted to agricultural land uses over the past several centuries. However, in conservation areas such as those in the Guanacaste and Tempisque regions of Costa Rica, tropical dry forests are regenerating due to management practices including fire suppression. To better understand the patterns of secondary succession occurring in Costa Rican tropical dry forest, we established 60 20 × 50 m plots in mature and regenerating forests in the Sector Santa Rosa (formerly known as Parque Nacional Santa Rosa) and Palo Verde National Park. Plots were stratified into three plant communities: tropical dry oak forest (Quercus oleoides) (SROAK), Santa Rosa tropical dry forest (SRTDF), and Palo Verde tropical dry forest (PVTDF). In these plots we measured and identified and all individuals >10 cm DBH, measured but did not identify stems <10 cm but taller than 1.3 m, counted woody seedlings (<1.3 m height) and analyzed soil chemical and physical properties.     

Pathogenesis of chicken-passaged Newcastle disease viruses isolated from chickens and wild and exotic birds

The pathogenesis of six Newcastle disease virus (NDV) isolates recovered from chickens (Ckn-LBM and Ckn-Australia) and wild (Anhinga) and exotic (YN parrot, pheasant, and dove) birds was examined after the isolates had been passaged four times in domestic chickens. Groups of 10 4-wk-old specific-pathogen-free white leghorn chickens were inoculated intraconjunctivally with each one of the isolates. The infected birds were observed for clinical disease and were euthanatized and sampled at selected times from 12 hr to 14 days postinoculation or at death. Tissues were examined by histopathology, by immunohistochemistry (IHC) to detect viral nucleoprotein (IHC/NP), and by in situ hybridization to detect viral mRNA and were double labeled for apoptosis (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling ([TUNEL] or IHC/caspase-3) and viral nucleoprorein (IHC/NP). Birds infected with the three low virulence viruses (Ckn-LBM, YN parrot, and Ckn-Australia) did not develop clinical disease. Microscopic lesions were observed only at the inoculation site and in organs of the respiratory system. The detection of viral nucleoprotein (N) was restricted to the inoculation site. The pheasant and dove isolates were highly virulent for chickens with marked tropism for lymphoid tissues, confirmed by the presence of large numbers of cells positive for viral N protein and viral mRNA. Viral N protein was detected early in the cytoplasm of cells in the center of the splenic ellipsoids. The apoptosis assays (TUNEL and IHC/caspase-3) showed increased apoptosis in the splenic ellipsoids as well. Apparently, apoptosis is an important mechanism in lymphoid depletion during NDV infection.     

Wet sieving versus dry crushing: Soil microaggregates reveal different physical structure,bacterial diversity and organic matter composition in a clay gradient

Soil microaggregates contain particles of different sizes, which may affect their potential to store organic carbon (OC). A variety of methods can be used to isolate microaggregates from the larger soil structures, among which wet sieving approaches are widely employed. We developed a novel dry crushing method that isolates microaggregates along failure planes due to mechanical stresses rather than hydraulic pressures and compared the mechanical stability, OC contents and microbial community composition between dry-crushed and wet-sieved samples with contrasting clay contents. Dry-crushed samples exhibited a higher stability and bacterial diversity compared to wet-sieved samples. As a result, the dry-crushed microaggregates had different size distributions when analysed dry and after wetting. In the dry state, dry-crushed microaggregates were larger and contained more sand-sized primary particles within the aggregate structures. The wetting of dry-crushed aggregates caused a disintegration of larger microaggregates and sand-sized primary particles into smaller microaggregates that contained finer particles. In the soils with lower clay contents, the diameter of dry-crushed microaggregates was 40 μm larger due to more sand-sized primary particles remaining within the aggregates. Depending on how much volume in microaggregates is occupied by large primary particles, the OC concentration increased in the soil with higher clay content. Wet-sieved size fractions also showed a similar pattern of OC distribution, whereas more primary particles were observed outside of aggregates. Wet sieving approaches disperse the soil into OC-rich aggregates and might be preferable if OC dynamics are investigated. Differences in bacterial community composition in dependence on clay content were more pronounced in dry-crushed microaggregates. If intact aggregate architectures are of interest for the isolation of soil structural units, the presented dry crushing method might provide an advantageous alternative that also better preserves bacterial diversity.     

Open versus closed bilateral anal sacculectomy for treatment of non-neoplastic anal sac disease in dogs: 95 cases (1969-1994)

OBJECTIVE: To determine complications associated with anal sacculectomy in dogs with non-neoplastic anal sac disease and compare complication rates for open versus closed techniques. DESIGN: Retrospective study. ANIMALS: 95 dogs. PROCEDURE: Medical records were reviewed for information on signalment, history, physical examination findings, type of anal sac disease, surgical technique (closed, standard open [surgery performed prior to 19801, or modified open [surgery performed after 19801), and postoperative complications. RESULTS: In 57 dogs, a closed technique was used, and in 38, an open technique was used. Only 3 dogs developed short-term complications (excessive drainage, scooting and inflammation, and seroma formation), and 14 developed long-term complications (continued licking of the surgery site, fecal incontinence, fistulation, and stricture formation). Development of postoperative complications was significantly associated with surgical technique. Dogs that underwent standard open sacculectomy prior to 1980 were 13.67 times as likely to have a long-term complication as were dogs that underwent closed sacculectomy. Weight of the dog, type of anal sac disease, age at the time of surgery, and whether the wound was closed surgically were not significantly associated with whether dogs developed postoperative complications. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that anal sacculectomy is a safe and effective treatment for non-neoplastic anal sac disease in dogs and is associated with a low rate of complications. The standard open technique was associated with the greatest number of complications, whereas complication rates for the closed and modified open techniques were similar to each other.     

Comparison of effects of dexamethasone and the leukotriene D4 receptor antagonist L-708,738 on lung function and airway cytologic findings in horses with recurrent airway obstruction

OBJECTIVE: To evaluate whether the leukotriene (LT) D4 receptor antagonist L-708,738 is therapeutically beneficial in treating horses with recurrent airway obstruction (heaves). ANIMALS: 12 adult horses with heaves and healthy lung lobes from 20 slaughtered horses. PROCEDURE: Lung lobes were used for smooth muscle tension and radioligand binding studies. Horses with heaves were given a placebo for 14 days and administered L-708,738 (n = 6; 2.5 mg/kg PO, q 12 h) or dexamethasone (6; 0.04 mg/kg, IV, q 24 h) from days 14 to 28. Pulmonary function was measured weekly for 36 days, and bronchoalveolar cells were collected on days 0,14, and 29 for cytologic examination. RESULTS: Nanomolar concentrations of L-708,738 were effective at antagonizing LTD4-induced bronchoconstriction and LTD4-receptor binding in lung lobes. Mean peak and trough L708,738 plasma concentrations during the treatment period were 1.54 and 0.28 microM, respectively. On days 21 and 29, lung mechanics were significantly improved in the dexamethasone-treated horses but not in the L-708,738-treated horses. Neither dexamethasone nor L-708,738 had a significant effect on cytologic findings. CONCLUSIONS AND CLINICAL RELEVANCE: L-708,738 was bioavailable after oral administration and sustained concentrations in plasma during the dosing period that exceeded in vitro efficacy values. However, airway function did not improve, suggesting that either drug concentrations in the lungs were subtherapeutic or that cysteinyl LT may not be important mediators of airway inflammation in heaves. Results provide the first evidence of cysteinyl LT1 receptors in airways of horses.