CONTROL AND EVALUATION OF BLOOD SERUM ASSAYS FOR PENICILLIN

A method for adequate control and evaluation of blood serum assays for penicillin is given and the effectiveness of the method for controlling the several types of penicillin is shown.     

Chloride in the pore water and water column of Onondaga Lake,N.Y., U.S.A.

The vertical distributions of Cl in the pore waters of the sediments and in the water column of Onondaga Lake, New York, are documented and used to estimate the diffusion flux of Cl across the sediment-water interface, and establish the reduction in lake concentrations that has occurred as a result of the closure of an industrial source of Cl. Despite the industrial enrichment of the water column with Cl over the last 100 yr, gradients within the upper sediments toward the overlying water of 6.9 to 8.5 × 10^?2 mg cm^?3 cm^?1 exist in the deep basins of the lake. These upwards gradients are apparently a manifestation of the salt deposits that underlie the region. The estimated diffusion flux from the sediments to the water column, 3.2 × 106 kg yr^?1, represents a small percentage of the external load during the operation of the industry (0.4%) and after its closure (1.6%). The Cl concentration has decreased approximately 70% in response to an approximately equal percent reduction in external loading, as a result of closure of the industry. This supports the position that the lake's concentrations largely reflect external loading and lake flushing associated with surface inputs.     

Estimating landscape resistance to dispersal

Dispersal is an inherently spatial process that can be affected by habitat conditions in sites encountered by dispersers. Understanding landscape resistance to dispersal is important in connectivity studies and reserve design, but most existing methods use resistance functions with cost parameters that are subjectively chosen by the investigator. We develop an analytic approach allowing for direct estimation of resistance parameters that folds least cost path methods typically used in simulation approaches into a formal statistical model of dispersal distributions. The core of our model is a frequency distribution of dispersal distances expressed as least cost distance rather than Euclidean distance, and which includes terms for feature-specific costs to dispersal and sex (or other traits) of the disperser. The model requires only origin and settlement locations for multiple individuals, such as might be obtained from mark–recapture studies or parentage analyses, and maps of the relevant habitat features. To evaluate whether the model can estimate parameters correctly, we fit our model to data from simulated dispersers in three kinds of landscapes (in which resistance of environmental variables was categorical, continuous with a patchy configuration, or continuous in a trend pattern). We found maximum likelihood estimators of resistance and individual trait parameters to be approximately unbiased with moderate sample sizes. We applied the model to a small grizzly bear dataset to demonstrate how this approach could be used when the primary interest is in the prediction of costs and found that estimates were consistent with expectations based on bear ecology. Our method has important practical applications for testing hypotheses about dispersal ecology and can be used to inform connectivity planning efforts, via the resistance estimates and confidence intervals, which can be used to create a data-driven resistance surface.     

The association between Chiari-like malformation,ventriculomegaly and seizures in cavalier King Charles spaniels

Cavalier King Charles spaniels (CKCSs) with Chiari-like malformation (CM) and associated seizures are frequently diagnosed with idiopathic epilepsy. There could be an association between ventriculomegaly (V) or caudal fossa overcrowding (CCFP) and seizures. A retrospective case-control study was performed using MRI to investigate the possible association between these morphological abnormalities and seizures. Seizure semiology and, where possible, electroencephalographic (EEG) abnormalities were documented. Eighty-five CKCS with CM were included, 27 with seizures. There was no association between V or CCFP and seizures (P = 0.10 and 0.71, respectively). Seizures were classified as having partial onset in 61% of individuals in the study population (95% CI 42.41–76.43%). Another cause of recurrent seizures in CKCS (such as familial epilepsy) is suspected, as previously reported.     

Imazethapyr aqueous photolysis, reaction quantum yield, and hydroxyl radical rate constant

The recent introduction of imidazolinone-tolerant rice varieties allow imazethapyr to be used in commercial rice. Little is known about imazethapyr photodegradation in the rice field. Laboratory studies were conducted to determine the direct and indirect photolysis rates for imazethapyr and to evaluate the photolysis of imazethapyr in three rice paddy waters. The reaction quantum yield (phi I) for imazethapyr was determined to be 0.023 +/- 0.002, while the hydroxyl radical rate constant (K(I)*OH) was 2.8 x 10(13) M(-1) h(-1). These results show that imazethapyr is susceptible to both direct and indirect photolysis reactions in water. The results also show that imazethapyr photolysis in paddy water will be affected by turbidity because of its impact on the availability of sunlight to drive direct and indirect photolysis reactions.     

Prospective evaluation of a peripherally administered three-in-one parenteral nutrition product in dogs

OBJECTIVES: Peripheral parenteral nutrition is an option for short-term nutritional support in dogs which cannot be supported with enteral nutrition. The objective of this study was to examine the use of a three-in-one, 840 mOsmol/l peripheral parenteral nutrition product containing amino acids, lipids and glucose in separate compartments in dogs. METHODS: Nine dogs were administered the three-in-one product, and two dogs were administered the amino acid part of the product, via a peripheral vein. Dogs were monitored for mechanical and metabolic complications. RESULTS: Mechanical complications (apparent thrombus or thrombophlebitis) caused failure of infusion at a median of 36 hours. None of the dogs appeared to develop catheter-related sepsis. Using a 10-hour infusion period appeared to decrease the incidence of line failure. Mild and clinically non-significant hyperglycaemia was the only metabolic complication. In four of the dogs, serum folate, cobalamin and homocysteine concentrations were determined before and after peripheral parenteral nutrition administration. Oral and parenteral administration of methionine has been previously associated with lowered serum folate concentrations. Low serum folates and the subsequent hyperhomocysteinaemia have been associated with venous endothelial damage and venous thrombus in other species. Serum cobalamin also affects homocysteine metabolism. Median serum folate, cobalamin and homocysteine concentrations were not affected by the short-term administration of this three-in-one product. CLINICAL SIGNIFICANCE: Using the product for 24 hours/day may require catheter replacement due to line failure. Other than line failure, which may be improved by 10- to 12-hour infusion times, this product was found to be safe and practical for short-term peripheral parenteral nutrition in dogs.     

Estimating Plant-Available Water in the Ap Horizon Using Geospatial Analysis of Field and SSURGO Data

Soil provides many of the requirements needed for terrestrial plant growth, including an adequate supply of water. Because the proportion of plant roots is usually greatest in the top 10 to 15 cm of soil, the soil moisture content in the Ap horizon is particularly important for plant growth and crop yields. Uncertainties in estimates of plant available water in the Ap horizon (AW_Ap) often arise from variabilities in field, laboratory and geospatial data at a farm scale. The objectives of this study were to quantify and compare AW_Ap estimates across the 147-ha Cornell University Willsboro research farm using four different approaches: a) AW_Ap calculated from values reported in the SSURGO database for available water capacity (AWC) and Ap thickness for the soil map units (SMUs) present on the farm, b) AW_Ap estimated from soil texture data reported for the SSURGO SMUs, c) AW_Ap estimated from soil texture data determined from soil cores taken across the farm that were then averaged within each SMU, and d) spatially interpolating the AW_Ap values predicted from soil cores across the entire farm irrespective of SMU boundaries. Available water in the Ap horizon varied with soil order in the general trend of Alfisols > Inceptisols > Entisols regardless of the estimation approach used. Field measurement-based estimates of AW_Ap were lower, in general than the reported SSURGO values and estimates based on reported texture in the SSURGO database. The higher abundance of coarse fragments in the Ap horizon of the soil cores collected on the farm partially explains the lower field measurement-based AW_Ap estimates. In the SSURGO database, values reported for AWC are frequently obtained from a selected pedon from a “type location” and not from the actual study location. These “type locations” can be located far from study sites and even in different states. Although collecting detailed field data may not always be possible due to the high costs of field and laboratory measurements, it is important to understand the potential benefits and limitations of making field-scale and regional AW estimates using the SSURGO database.     

Antimicrobial Resistance Impacts Clinical Outcome of Granulomatous Colitis in Boxer Dogs

Background: Escherichia coli have recently been identified within the colonic mucosa of Boxer dogs with granulomatous colitis (GC). Eradication of invasive E. coli is associated with clinical and histological remission. Objectives: To determine antimicrobial susceptibility profiles of E. coli strains from GC and healthy dogs, and the association of antimicrobial resistance with clinical outcome. Animals: Fourteen Boxer dogs with GC and 17 healthy pet dogs. Methods: Prospective study: E. coli was cultured from GC biopsies and rectal mucosal swabs of healthy dogs. Individual strains were selected by phylogroup and overall genotype, determined by triplex‐ and random amplified polymorphic DNA‐polymerase chain reaction respectively. Antimicrobial susceptibility was determined by broth microdilution minimal inhibitory concentration. Results: Culture yielded 23 E. coli strains from GC (1–3/dog, median 2) and 34 strains from healthy (1–3/dog, median 2). E. coli phylogroups were similar (P= .18) in GC (5A, 7B1, 5B2, 6D) and healthy (2A, 10B1, 15B2, 7D). Resistance to ampicillin, amoxicillin‐clavulanate, cefoxitin, tetracycline, trimethoprim‐sulfa (TMS), ciprofloxacin, and chloramphenicol was greater (P < .05) in GC (21–64%) than healthy (0–24%). Enrofloxacin resistant E. coli were isolated from 6/14 GC versus 0/17 healthy (P= .004). Of the enrofloxacin resistant cases, 4/6 were also resistant to macrophage‐penetrating antimicrobials such as chloramphenicol, rifampicin, and TMS. Enrofloxacin treatment before definitive diagnosis was associated with antimicrobial resistance (P < .01) and poor clinical outcome (P < .01). Conclusions and Clinical Importance: Antimicrobial resistance is common among GC‐associated E. coli and impacts clinical response. Antimicrobial therapy should be guided by mucosal culture and antimicrobial susceptibility testing rather than empirical wisdom.