Superficial keratectomy and cryosurgery as therapy for limbal neoplasms in 13 horses

Objective To determine the usefulness and clinical outcome of a combined procedure of superficial keratectomy and cryosurgery as a treatment for limbal neoplasms in horses. Study design Retrospective study. Animals Thirteen horses with 14 limbal tumors. Methods Medical records of all patients with limbal tumors, referred to the Department of Equine Sciences of Utrecht University between 1995 and 2002, were retrieved. Patient data were analyzed with respect to signalment, tumor surface area and histologic diagnosis. Surgery, performed under general anesthesia, included surgical debulking of the tumor followed by cryosurgery. Long‐term follow‐up information was obtained by re‐evaluation in the clinic, by the referring veterinarian, and/or by telephone enquiry. Results Therapy was successful in 9 out of 14 eyes after the first attempt (64%); one eye needed retreatment (7%), and four eyes were eventually enucleated (29%). The mean follow‐up period was 4.8 years. The initial surface area of the tumor significantly influenced outcome (P < 0.01). Squamous cell carcinoma was the most predominant tumor type (79%). Haflinger horses accounted for 69% of the cases whereas their occurrence in the overall hospital population is approximately 5%. Conclusions and clinical relevance The described technique of superficial keratectomy and cryosurgery is a simple procedure for the treatment of limbal tumors in equine patients that does not require sophisticated equipment. Nor is it tampered by legal restriction, and appears to be effective in tumors with a small surface area (< 2 cm²). Haflinger horses seem to be predisposed for the development of ocular squamous cell carcinoma.     

Pig producer attitude towards surgical castration of piglets without anaesthesia versus alternative strategies

A group of 160 Flemish pig farmers (n=160) were surveyed about their attitude towards surgical castration with anaesthesia (SCA) and without (SCN), immunocastration (IC), sperm sexing (SS) and the production of entire males (EM). The farmers' general preference was recorded as SCN>SS>SCA=IC>EM. The farmers' self-reported knowledge of the strategies was associated with their preference for SCA (negatively) and SS (positively). Herd size was correlated with farmers' preference for SCA (negatively) and SS (positively). Farmers perceived surgical castration without anaesthesia as the most favourable strategy in terms of farm profitability, animal performance and effectiveness against boar taint, but they expected the lowest consumer acceptance for this strategy. Surgical castration with anaesthesia was ranked the least favourable in terms of labour conditions. Production of entire males was viewed as the least profitable and the least effective strategy. Sperm sexing was positively perceived, particularly in terms of labour conditions, animal welfare, effectiveness and expected consumer acceptance. The farmers' opinion was quite homogeneous, especially regarding surgical castration without anaesthesia and production of entire males. Increasing our understanding of the farmers' perceptions will hopefully facilitate communication about this intricate issue.     

Nutritional support for patients

A good intake of fluids and essential nutrients in the first fourteen days is of vital importance to recuperating animals. Moreover, it is important to encourage cats and dogs to eat after illness or surgery, in order to promote optimal functioning of the gut and the immune system. Enteral nutrition is to be preferred to nasogastric feeding or parenteral nutrition. In the first stage of recovery, during the first 24 to 48 hours, it is important to feed the gut' with nutrients, and thereafter, in the second stage of recovery (after day 3), the calorie intake can be increased. Timely nutritional support with nutraceuticals, such as arginine, glutamine, taurine, long-chain polyunsaturated omega-3 fatty acids, and prebiotic fibres, can considerably shorten the recovery period of cats and dogs after illness or surgery     

Characterisation of the first wheat (Triticum aestivum L.) nucleotide pyrophosphatase/phosphodiesterase resembling mammalian counterparts

A formerly unknown nucleotide pyrophosphatase/phosphodiesterase (NPP) of wheat (Triticum aestivum L.) (TaNPP) was recombinantly produced in Pichia pastoris (TaNPPr) following assembly of the sequence out of wheat ESTs using sequences of known NPPs. Simultaneously, a phosphodiesterase was purified to homogeneity from wheat germs, characterised and identified as TaNPP. TaNPP contains the highly conserved catalytic substrate and metal binding residues and displays properties [high pH optimum, glycosylation, high thermostability and inhibition by EDTA and adenosine 5′-monophosphate (AMP)] similar to those of mammalian enzymes characterised earlier. The sequence of TaNPP includes that of a putative transmembrane domain, a characteristic of most NPPs. Both recombinant and native TaNPP partially occur as oligomeric proteins on SDS PAGE. Upon addition of DTT, both migrate as monomeric proteins. Part of the native wheat protein even occurs in its truncated form, thus lacking the transmembrane region. Out of a range of tested natural substrates, TaNPP had the highest affinity towards adenine containing nucleotides. While Michaelis-Menten kinetics were valid in the low substrate concentration range, at higher concentrations, they were no longer applicable. TaNPP shows no similarity to the recently characterised rice and barley enzymes and, is hence, one of the first characterised plant NPPs resembling mammalian NPPs.     

Haloperoxidase Mediated Quorum Quenching by Nitzschia cf pellucida: Study of the Metabolization of N-Acyl Homoserine Lactones by a Benthic Diatom

Diatoms are known to produce a variety of halogenated compounds, which were recently shown to have a role in allelopathic interactions between competing species. The production of these compounds is linked to haloperoxidase activity. This research, has shown that this system may also be involved in diatom-bacteria interactions via the H₂O₂ dependent inactivation of a type of quorum sensing (QS) molecule, i.e., N-β-ketoacylated homoserine lactones (AHLs), by a natural haloperoxidase system from the benthic diatom Nitzschia cf pellucida. The AHL degradation pathway towards corresponding halogenated derivatives was elucidated via HPLC-MS analysis and the synthesis of a broad series of novel halogenated AHL analogues as reference compounds. Furthermore, their biological activity as quorum sensing modulators was directly compared and evaluated against a series of naturally occurring β-keto-AHLs. It has been demonstrated that the loss of the QS activity results from the final cleavage of the halogenated N-acyl chain of the signal molecules.     

Computed leaching of pesticides from soil under field conditions

With a computer model, pesticide behavior in soil after spring application to a sandy loam field with a potato crop, was simulated. Special attention was paid to the risk of leaching through the upper meter of soil in catchment areas. Unsaturated water flow resulting from rainfall was modeled in some detail. Uptake of water and solute by the developing root system of the annual crop was included in the model. The computations were carried out for hypothetical pesticides with first-order decomposition rate constants in soil of 0.03, 0.01, 0.003, and 0.001 day^–1 at 20°C. Adsorption decreased with increasing soil depth and the adsorption coefficient for the top layer ranged from 0.0 to 10.0. For 20 combinations of decomposition rates and adsorption strengths, the extent of leaching from a top layer 1 m thick was computed. With a decomposition rate constant at 20°C of 0.03 day^–1 or higher, leaching was extremely low; with 0.01 days^–1 leaching was 1.7% of the dosage or lower. For compounds with a high persistence and mobility, leaching from the soil ranged up to about 10% of the dosage or more. Besides decomposition, uptake by plants was an important factor in reducing leaching, particularly for the weakly adsorbed and comparatively persistent compounds.     

Novel Alkaloids from Marine Actinobacteria: Discovery and Characterization

The marine environment is an excellent resource for natural products with therapeutic potential. Its microbial inhabitants, often associated with other marine organisms, are specialized in the synthesis of bioactive secondary metabolites. Similar to their terrestrial counterparts, marine Actinobacteria are a prevalent source of these natural products. Here, we discuss 77 newly discovered alkaloids produced by such marine Actinobacteria between 2017 and mid-2021, as well as the strategies employed in their elucidation. While 12 different classes of alkaloids were unraveled, indoles, diketopiperazines, glutarimides, indolizidines, and pyrroles were most dominant. Discoveries were mainly based on experimental approaches where microbial extracts were analyzed in relation to novel compounds. Although such experimental procedures have proven useful in the past, the methodologies need adaptations to limit the chance of compound rediscovery. On the other hand, genome mining provides a different angle for natural product discovery. While the technology is still relatively young compared to experimental screening, significant improvement has been made in recent years. Together with synthetic biology tools, both genome mining and extract screening provide excellent opportunities for continued drug discovery from marine Actinobacteria.     

Analysis of return flows in a tank cascade system in Sri Lanka

In Sri Lanka, irrigation reservoirs (tanks) are usually connected sequentially and form cascades along the landscape. A study was carried out in the Anuradhapura District in the dry zone of Sri Lanka to understand the role of return flows in such tank cascade systems. The water balance of a tank cascade system was estimated using hydrological data collected over a one-year period. The system was extended about 25 km along a river composed of three small reservoirs having the command area of 31, 55, and 55 ha, respectively. In this system, about 46% of seepage water from tanks entered the paddy fields of the command area. The crop consumed part of the water and the rest returned to the downstream tank through the drainage canals. Percolation loss in the command areas was low (3.6 mm/day) since a considerable portion of the percolation returned to the downstream tank. These results showed that return flows, which are generally disregarded in the water budget, contributed considerably to the water supply of the tank cascade system.     

Comparison of measured and simulated changes in base cation amounts using a one-layer and a multi-layer soil acidification model

Biogeochemical processes describing nutrient cycling strongly affect the development of different soil horizons and soil acidification. However, in many soil acidification models these processes are not directly simulated, and spatially distributed soil properties are lumped into average values. This paper describes the extension of a one-layer soil acidification model (SMART) to a multi-layer model (SMARTEX) by including nutrient cycling, and the performance of both models regarding their ability for the assessment of the effects of acid deposition on forest soil. This was done by comparing simulation results of the two models with respect to changes in base cation amounts to historical data from sites in south Sweden. The results showed that the multi-layer model gives better results for the top soil, whereas the one-layer model gives better results for the rootzone and the total profile. Since the top soil is most important, the extended model is more suited to relate acid deposition to forest growth than the more general results of the one-layer model. However, the sensitivity of the multi-layer model to some parameters is large. A change in these parameters had strong effects on the separate layers, whereas the effects were cancelled out over the total profile. This sensitivity requires a careful parameterization of the model which might be troublesome to lack of data.