Comparing concurrent in situ and batch‐extracted trace element concentrations

Different procedures to investigate dissolved trace element concentration at the transition from unsaturated to saturated zone in soils were compared by concurrent sampling of soil solution and solid soil material in this zone. The in situ sampled soil solution from the percolated water was used to measure in situ concentrations, while solid soil material was used to measure concentrations at two liquid–solid ratios using batch experiments on 250 sample pairs. The liquid–solid ratios were 2 L kg^–1 and 5 L kg^–1. At 5 L kg^–1, the ionic strength was adjusted with Ca(NO₃)₂ to a sample‐specific value similar to in situ, while at 2 L kg^–1, the ionic strength was not adjusted. The extracted concentrations of most trace elements exhibited a statistically significant but weak correlation (p value < 0.01) to the corresponding in situ concentrations. In the liquid–solid ratio of 2 L kg^–1 extracts, Pb and Cr showed very poor comparability with the in situ equivalent. A likely cause was the enhanced dissolved‐organic‐C release in the extract due to the lower ionic strength compared to in situ conditions in combination with effects from drying and moistening soil samples. For the other elements, correlation increased in the order As < Cu, Zn, Sb, Mo, V < Cd, Ni, Co where adjustment of the ionic strength led to slightly better results. In addition to the element‐specific shortcomings, it appeared that low concentration levels of in situ concentrations were generally underestimated by batch extraction methods. The liquid–solid ratio of 2 L kg^–1 extracts could only be used as a method to predict exceedance of thresholds if a safety margin of approximately one order of magnitude higher than the thresholds was adopted. The ability of the batch‐extraction methods to estimate in situ concentrations was equally limited.     

The effect of UV-blocking contact lenses as a therapy for canine chronic superficial keratitis

Objective To evaluate the effect of UV‐blocking soft contact lenses in treatment for chronic superficial keratitus (CSK). Methods Twenty six dogs with CSK were treated continuously with UV‐blocking contact lenses for 6 months. A contact lens was placed on one eye of each dog; the other eye remained without a lens as a control eye. After this primary study, five of the dogs were further treated and they wore then contact lenses in both eyes. Continuously, all patients were concurrently treated topically with cyclosporine. The contact lenses were changed every 4 weeks and an ophthalmic examination performed. Evaluation criteria included corneal alterations as pigmentation, edema, pannus and vascularization. To determine the transmittance characteristics of the contact lenses before and after use, 32 contact lenses were measured with a UV‐vis‐NIR spectrophotometer. Results Pigmentation increased in eyes wearing lenses and in control eyes over the evaluation period of 6 months. Corneal edema increased in the eyes wearing lenses, but remained unaffected in the control eyes. A significant difference in the incidence of pannus and the extent of corneal vascularisation could not be evaluated. Adverse effects were noted in six cases (corneal edema and vascularisation, conjunctivitis, blepharospasm). All new lenses studied reduced UV‐radiation to a safe level, whereas used lenses did not maintain their transmittance characteristics. Conclusions No positive effect of UV‐blocking contact lenses could be proven with the study design used.     

Can the mammalian organoid technology be applied to the insect gut?

Mammalian intestinal organoids are multicellular structures that closely resemble the structure of the intestinal epithelium and can be generated in vitro from intestinal stem cells under appropriate culture conditions. This technology has transformed pharmaceutical research and drug development in human medicine. For the insect gut, no biotechnological platform equivalent to organoid cultures has been described yet. Comparison of the regulation of intestinal homeostasis and growth between insects and mammals has revealed significant similarities but also important differences. In contrast to mammals, the differentiation potential of available insect cell lines is limited and can not be exploited for in vitro permeability assays to measure the uptake of insecticides. The successful development of in vitro models could be a result of the emergence of molecular mechanisms of self‐organization and signaling in the intestine that are unique to mammals. It is nevertheless considered that the technology gap is a consequence of vast differences in knowledge, particularly with respect to culture conditions that maintain the differentation potential of insect midgut cells. From the viewpoint of pest control, advanced in vitro models of the insect midgut would be very desirable because of its key barrier function for orally ingested insecticides with hemolymphatic target and its role in insecticide resistance. © 2020 Society of Chemical Industry     

Carbon flow into microbial and fungal biomass as a basis for the belowground food web of agroecosystems

The origin and quantity of plant inputs to soil are primary factors controlling the size and structure of the soil microbial community. The present study aimed to elucidate and quantify the carbon (C) flow from both root and shoot litter residues into soil organic, extractable, microbial and fungal C pools. Using the shift in C stable isotope values associated with replacing C3 by C4 plants we followed root- vs. shoot litter-derived C resources into different soil C pools. We established the following treatments: Corn Maize (CM), Fodder Maize (FM), Wheat + maize Litter (WL) and Wheat (W) as reference. The Corn Maize treatment provided root- as well as shoot litter-derived C (without corn cobs) whereas Fodder Maize (FM) provided only root-derived C (aboveground shoot material was removed). Maize shoot litter was applied on the Wheat + maize Litter (WL) plots to trace the incorporation of C4 litter C into soil microorganisms. Soil samples were taken three times per year (summer, autumn, winter) over two growing seasons. Maize-derived C signal was detectable after three to six months in the following pools: soil organic C (C_org), extractable organic C (EOC), microbial biomass (C_mic) and fungal biomass (ergosterol). In spite of the lower amounts of root- than of shoot litter-derived C inputs, similar amounts were incorporated into each of the C pools in the FM and WL treatments, indicating greater importance of the root- than shoot litter-derived resources for the soil microorganisms as a basis for the belowground food web. In the CM plots twice as much maize-derived C was incorporated into the pools. After two years, maize-derived C in the CM treatment contributed 14.1, 24.7, 46.6 and 76.2% to C_org, EOC, C_mic and ergosterol pools, respectively. Fungi incorporated maize-derived C to a greater extent than did total soil microbial biomass.     

EFFECT OF SEVOFLURANE ANESTHESIA AND BLOOD DONATION ON THE SONOGRAPHIC APPEARANCE OF THE SPLEEN IN 60 HEALTHY CATS

The aims of this prospective study were to describe the normal sonographic size and appearance of the feline spleen, and to test effects of sevoflurane anesthesia and blood collection on sonographic characteristics. Sonographic evaluations were performed in 60 healthy blood donor cats prior to anesthesia and blood collection (baseline), after anesthesia induction, after completion of blood collection while under anesthesia, and 7–10 days after blood collection. Transverse sonographic images of the splenic mid‐body were made. Splenic height, width, cross‐sectional area, echogenicity relative to the left renal cortex, and echotexture were recorded. Height, width, and cross‐sectional area were compared across time periods using linear‐mixed effects models. Holm's method was applied to adjust for multiplicity and control the overall Type 1 error rate at α = 0.05. Normal transverse sonographic splenic measurements (mean ± standard deviation) at baseline were: height 8.2 ± 1.4 mm; width 26.7 ± 4.4 mm; and CSA 1.6 ± 0.5 cm². While there were statistically significant differences in splenic height, width, and cross‐sectional area after sevoflurane anesthesia and/or blood collection, differences were of low magnitude. The spleen was diffusely homogenous and subjectively isoechoic or mildly hyperechoic relative to the left renal cortex. In 77% of castrated male cats, the spleen was isoechoic to the left renal cortex. We conclude that sevoflurane anesthesia and blood donation do not subjectively alter splenic dimensions, echogenicity and echotexture in normal cats.     

RADIOGRAPHIC CHARACTERIZATION OF PRESUMED PLATE‐LIKE ATELECTASIS IN 75 NONANESTHETIZED DOGS AND 15 CATS

Discrete discoid or linear areas of increased soft opacity have been observed within the pulmonary parenchyma in thoracic radiographs of dogs and cats. Similar radiographic findings have been described in humans and termed plate‐like atelectasis. The purpose of this retrospective study was to describe locations and characteristics of presumed plate‐like atelectasis, presence of concurrent thoracic disease(s), and presence of persistent pulmonary changes on recheck thoracic radiographic studies in a cohort of dogs and cats. Hospital records between 2004 and 2011 were searched and a total of 90 cases were included (75 dogs and 15 cats, 2–17 years of age). Plate‐like atelectasis was most commonly found in left lateral radiographs. Plate‐like atelectasis was observed in the cranial thorax and was oriented in a dorsocranial to ventrocaudal direction in 68 (75%) patients. Plate‐like atelectasis averaged 29.6 ± 14.4 mm in length and 2.6 ± 1.3 mm in width. In 57 of the 90 patients (63%), plate‐like atelectasis was the only abnormality found. Plate‐like atelectasis was present in 7 of 22 cases where follow‐up radiographs were available. Findings from the current study indicated that, while the etiology of plate‐like atelectasis remains unknown, anatomic variations in sublobar pulmonary anatomy might account for pleural areas of atelectasis. The authors propose that the presence of plate‐like atelectasis may represent areas of atelectasis that track along sublobar lung lobe separations, an area of hypoventilation or decreased collateral ventilation, and/or area of decreased localized surfactant deficiency.     

Semen parameters and testicular dimensions in small breed dogs below ten‐kilogram bodyweight

Because of few available data on semen parameters in small breed dogs, the study aimed to analyse semen and measure testes of dogs ≤10.0 kg bodyweight. Semen was collected from 41 fertile stud dogs, which were divided based on bodyweight: group 1 ≤ 5.0 kg and group 2 between 5.1 and 10.0 kg. Median values for ejaculate volume (group 1: 1.2 ml; group 2: 2.2 ml), total sperm output (group 1: 110.7 × 10⁶; group 2: 215.1 × 10⁶) and testicular volume (group 1: left testicle 2.8 ml, right testicle 2.7 ml; group 2: left testicle 5.5 ml, right testicle 5.0 ml) were lower in group 1 compared to dogs of group 2 (p = .001; p = .001; both testes: p < .001). There was no difference in sperm concentration (p = .985). Based on these results, introduction of an additional weight group to the commonly used reference values is recommended, since values for ejaculate volume, total sperm output and testicular dimensions for dogs ≤5.0 kg bodyweight differed significantly from values of dogs with a bodyweight from 5.1 to 10.0 kg.     

Comparison of field methods in vegetation monitoring

For the purpose of vegetation monitoring, three methods for estimating plant cover, namely visual-estimate (VE), point-frequency (PF) and subplot-frequency (SF), were compared with regard to accuracy, precision, sensitivity and time consumption. The cover estimates by the three methods were compared with ‘true’ values measured on photographs using an image analysis technique. VE had the highest accuracy, precision and sensitivity. PF systematically overestimated cover. The greatest drawback of PF was the low sensitivity to species detection. It failed to detect 22–30% of the species in two forests and a bog. SF has high precision and sensitivity but low accuracy. Time consumption on one quadrat was about 6 min for VE and SF, 8.5 min for PF. Inter- and intra-person error with the three methods depends on plants. Inter-person error with VE was slightly greater for small and wide-spread plants, especially mosses, than for other life-forms. For wide-spread plants, intra-person error was slightly greater with PF than with the other methods. VE and PF are strongly correlated and convertible, but SF is neither correlated nor convertible with the other methods.