Canine insulinomas appear hyperintense on MRI T2‐weighted images and isointense on T1‐weighted images

Clinical and imaging diagnosis of canine insulinomas has proven difficult due to nonspecific clinical signs and the small size of these tumors. The aim of this retrospective case series study was to describe MRI findings in a group of dogs with pancreatic insulinomas. Included dogs were presented for suspected pancreatic insulinoma, MRI was used to assist with localization of the primary lesion, and the diagnosis was confirmed with surgical exploratory laparotomy and histopathology. The MRI studies for each dog were retrieved and the following data were recorded: T1‐weighted and T2‐weighted signal intensities, type of contrast enhancement, size and location of the primary lesion, and characteristics of metastatic lesions (if present). A total of four dogs were sampled. In all patients, the insulinoma displayed high‐intensity signal on T2‐weighted fat saturation images, similar to human studies. On postcontrast T1‐weighted fat saturation images, the tumors were primarily isointense to normal pancreatic tissue, in contrast to human studies where a low‐intensity signal is typically identified. Abnormal islet tissue was detected with MRI in all four dogs and metastases were identified in three dogs. Variations in the MRI appearance of primary and metastatic lesions were identified and could have been related to the variation of tissue composition, including the presence of neoplastic cells, hemorrhage, and fibrovascular stroma, and to the transformation of this tissue throughout the disease process.     

Appearance and migration of the horse-chestnut leafminer Cameraria ohridella in relation to city size and leaf-raking, using the example of two cities in Western Poland

Possible differences in the size and dynamics of the appearance of particular generations of Cameraria ohridella were studied at two city sites of different size and character. The differences in the degree of infestation of Aesculus hippocastanum by the horse chestnut leafminer in the two towns are interpreted as a result of the differences in the size of food resources. The greater degree of infestation of trees in Mosina relative to trees in Pozna is most probably a result of the difficulty of aerial dispersion and thereby much stronger competition for food. This conclusion confirms a positive correlation of the distance between localities with the degree of tree infestation in a small town and the lack of such a correlation in a big city. The presence of refuges in the city outskirts at which no raking and removal of leaves is performed does not seem to have a significant effect on the degree of horse chestnut infestation in the centre.     

Comparison of the Transport of Tetracycline-Resistant and Tetracycline-Susceptible Escherichia coli Isolated from Lake Michigan

It was recently reported that tetracycline could enhance the mobility of manure-derived Escherichia coli within saturated porous media (Walczak et al. (Water Research 45:1681-1690, 2011)). It was also shown, however, that E. coli from various sources could display marked variation in their mobility (Bolster et al. (Journal of Environmental Quality 35:1018-1025, 2009)). The focus of this research was to examine if the observed difference in the mobility of manure-derived tetracycline-resistant (tet(R)) and tetracycline-susceptible (tet(S)) E. coli strains was source-dependent. Specifically, E. coli were isolated from Lake Michigan, and the influence of tetracycline resistance on Lake Michigan-derived E. coli was investigated through column transport experiments. Additionally, a variety of cell morphology and surface properties were determined and related to the observed bacterial transport behavior. Our experimental results showed that, consistent with previous observations, the deposition rate coefficients of the tet(R)E. coli strain was ~20-100% higher than those of the tet(S)E. coli strain. The zeta potential of the tet(R)E. coli cells was ~25 mV more negative than the tet(S)E. coli cells. Because the surfaces of the E. coli cells and the quartz sands were negatively charged, the repulsive electrostatic double-layer interaction between the tet(R)E. coli cells and the quartz sands was stronger, and the mobility of the tet(R)E. coli cells in the sand packs was thus higher. The tet(R)E. coli cells were also more hydrophilic than the tet(S)E. coli cells. Results from migration to hydrocarbon phase (MATH) tests showed that about ~35% more tet(S)E. coli cells partitioned to the hydrocarbon phase. As it was previously shown that cell hydrophobicity could enhance the attachment of bacterial cells to quartz sand, the difference in cell hydrophobicity could also have contributed to the observed higher mobility of the tet(R)E. coli cells. The size of the tet(R) and tet(S)E. coli cells were similar, suggesting that the observed difference in their mobility was not size-related. Characterization of cell surface properties also showed that tet(R) and tetS E. coli cells differed slightly in cell-bound lipopolysaccharide contents and had distinct outer membrane protein profiles. Such difference could alter cell surface properties which in turn led to changes in cell mobility.     

Manure as a Source of Antibiotic-Resistant Escherichia coli and Enterococci: a Case Study of a Wisconsin, USA Family Dairy Farm

The spread of antibiotic-resistant bacteria in the environment is raising serious public health concerns, and manure is being increasingly recognized as a major source of antibiotic-resistant bacteria. In this research, we isolated Escherichia coli and enterococci from manure produced in a Wisconsin, USA family dairy farm to determine their resistance to six representative antibiotics. The average densities for E. coli and enterococci were 6.37(±4.38)?×?10⁷ colony formation units (CFU)?g^?1 and 1.60(±1.57)?×?10⁴ CFU g^?1, respectively. The E. coli isolates were found to be resistant to cephalothin, ampicillin, tetracycline, and erythromycin. In addition to these four antibiotics, the Enterococcus isolates were also resistant to gentamicin and ciprofloxacin. Additionally, we examined the survival and growth of E. coli and enterococci in dairy manure over a period of ~3 days. While the densities of enterococci remained stable over the study period, the concentrations of E. coli on average increased by 1.5 log10 units. Further tests of the bacterial antibiotic resistance over time showed no significant changes in the prevalence of antibiotic resistance. This result indicated that slightly aged manure could represent a larger source of antibiotic-resistant E. coli than fresh manure and the accumulation of antibiotic-resistant E. coli and enterococci in the agricultural fields must be accounted for in the modeling of the spread of antibiotic-resistant bacteria in the environment.     

Influence of Desiccation on the Transport of <Emphasis Type="Italic">Escherichia coli</Emphasis> through Saturated Sand Packs

Bacterial cells that enter the groundwater system commonly experience desiccation stresses (i.e., bacterial cells are directly exposed to air) when traveling through the unsaturated layer of soil. Little is known about the effects of desiccation on the transport of bacterial cells in the groundwater system. In this research, we investigated the transport of desiccated and non-desiccated Escherichia coli K12 (ATCC 10798) cells through saturated sand packs using laboratory column transport experiments. Cell desiccation was performed at 25°C under relative humidity (RH) levels of 22%, 53%, 75%, and 97%, respectively, and the desiccation duration was 22 h. Our results showed that desiccation reduced the viability of E. coli cells under all RH levels and increased the transport of E. coli cells under ≥75% RH levels. The increase in the transport of the desiccated E. coli cells was not related to changes in cell size or cell zeta potential. Desiccation under high (i.e., ≥75%) RH levels, however, led to lower cell hydrophobicity, which was found to be positively correlated with cell transport.     

Radiography and ultrasonography of pneumatosis intestinalis in a cat

An adult cat was presented for acute history of vomiting and collapse. Radiographs showed the presence of air within small intestinal walls and arborizing gas patterns within the liver, compatible with pneumatosis intestinalis and presumed portal venous gas, respectively. An abdominal ultrasound the following day was suggestive of gas within the intestinal wall, however, gas within the hepatic vasculature, parenchyma, or biliary tree was not evident. Due to progressive clinical deterioration of the patient, the owners elected humane euthanasia. Necropsy revealed severe necrotizing hemorrhagic enterotyphlocolitis secondary to Clostridium difficile toxin.     

Evaluating soil salinity status from bulk electrical conductivity and permittivity

In the range of volumetric water content, θ, from about 0.12 cm³ cm^–3 to saturation the relation between bulk electrical conductivity, C_b, and bulk electrical permittivity, ε, of mineral soils was observed to be linear. The partial derivative ?C_b/?ε appeared independent of the moisture content and directly proportional to soil salinity. We found that the variable X_s = ?C_b/?ε determined from in situ measurements of C_b(θ > 0.2) and ε(θ > 0.2) can be considered as an index of soil salinity, and we call it the ‘salinity index’. Knowing the index and sand content for a given soil we could calculate the electrical conductivity of the soil water, C_w, which is a widely accepted measure of soil salinity. The two variables from which the salinity index can be calculated, i.e. C_b and ε, can be read simultaneously from the same sensor by time-domain reflectometry. Quantities and symbols a constant /dS m^–1 b constant c constant /dS m^–1 C _b electrical conductivity of bulk soil /dS m^–1 C _b′ constant equal to 0.08 dS m^–1 C _s electrical conductivity of a solution used to moisten soil samples /dS m^–1 C _w electrical conductivity of soil water defined as the soil salinity /dS m^–1 C _wref reference salinity (that truly existing) resulting from the procedure of moistening samples, expressed as C_s + C_r/dS m^–1 C _r baseline value of C_s due to residual soluble salts present in the soil /dS m^–1 d constant D dry soil bulk density /g cm^–3 l slope r ratio S sand content /% by weight t time /s X _s salinity index /dS m^–1 X _si initial salinity index when distilled water is used to moisten soil samples /dS m^–1 Y a moisture-independent salinity-dependent variable /dS m^–1 z coordinate along direction of flow of the soil solution ε′ constant equal to 6.2 ε relative bulk electrical permittivity (dielectric constant) of the soil θ volumetric water content determined thermogravimetrically using oven-drying /cm³ cm^–3     

Application of time-domain reflectometry (TDR) soil moisture miniprobe for the determination of unsaturated soil water characteristics from undisturbed soil cores

Summary Construction and operating characteristics of a TDR soil moisture miniprobe, that can be inserted through the wall of a metal cylinder, are shown. A laboratory stand for monitoring unsaturated water flow in undisturbed soil cores, involving a set of TDR miniprobes in combination with a set of minitensiometers, is described. This stand was used for frequent readings of instantaneous profiles of moisture and matric potential during transition from saturated to air dry state, in order to compute the unsaturated soil water characteristics. Some methodical aspects of the applied data processing algorithm are outlined.     

Ein Vergleich und eine Bewertung von Dränformeln für die Drändistanz von geschichteten Grund- und Stauwasserböden

A comparison and an evaluation of drain spacing equations for layered soils Drain spacings, calculated with different steady-state tile drainage formulas for layered soils, were compared. The formulas under consideration were those of Ernst, van Beers and of Toksöz and Kirkham. It was found that, for certain ranges of the drainage parameters, the drain spacings compare well. For other conditions, differences of over 100 percent did occur. Especially, results obtained with the Ernst equation may deviate considerably from those of the other authors. However, also drain spacings calculated with the van Beers equation do occasionally differ from those of Toksöz and Kirkham. For practical use the equation of Toksöz and Kirkham is recommended.