Proof-of-concept study: Evaluation of plasma and urinary electrolytes as markers of response to L-asparaginase therapy in dogs with high-grade lymphoma

Response to chemotherapy is one of the most important prognostic factors in dogs with lymphoma. The objective of this feasibility study was to evaluate if clinical responses to a specific cytotoxic agent (L-asparaginase) could be anticipated by measuring analyte concentrations in plasma and urine concentrations of lymphoma-bearing dogs. We hypothesized that potassium and phosphate concentrations in plasma and urine would be higher in dogs that completely responded to therapy. Plasma and urine samples of dogs with lymphoma were obtained before 12 and 24 hours after intramuscular L-asparaginase injections. Peripheral lymph node volumes were evaluated according to the Veterinary Cooperative Oncology Group standardized criteria. Plasma and urine electrolyte, calcium, phosphate, creatinine, urea, total protein, and albumin concentrations were measured, and the fractional excretions of each electrolyte were calculated. Statistical analyses compared complete vs partial responders using a linear regression model. Contrast analyses were also performed to differentiate the mean of each group, with adjustments made with the Benjamini-Hochberg procedure. Fourteen dogs were included, eight with complete responses, and six with partial responses. Plasma phosphate concentrations were significantly higher at 12 hours (P = .0003) and 24 hours (P = .009) after complete responses to therapy. This study demonstrates the potential use of plasma and urine analyte monitoring after chemotherapy induction. Plasma phosphate measurements represent a potential indicator of early responses to L-asparaginase therapy. Larger population studies are warranted to confirm these preliminary results.     

环保型可重复利用的海棉无土栽培基质的应用研究

用后处理和高成本是基质栽培的两大主要问题。岩棉已被公认为适用基质，但其主要问题是使用寿命短（最多2－3年）和每年产生大量的不可降解的废物。环境学家和政府部门调查研究显示，急需应用环保型可重复利用的无土栽培基质。本试验对新岩棉，椰子壳和已使用5年的海棉基质作了比较研究，旨在了解不同基质对温室番茄根限际环境、生长、发育和产量的影响，为海绵是否可作为番茄无土栽培适用于基质和提出有效的栽培管理措施提供理论依据。研究表明，海棉基质根际环境中EC和PH值比岩棉基质更稳定，每棉采果数，平均单果重，果实总重和和果实质量，海棉基质和岩棉基质无明显差异，但低于椰子壳基质，相对基传统的岩棉基质，已使用多年的海绵基质对番茄产量和质量无不良影响。海绵可作为温室番茄经济环保型基质。     

Apolipoprotein L-I promotes trypanosome lysis by forming pores in lysosomal membranes

Apolipoprotein L-I is the trypanolytic factor of human serum. Here we show that this protein contains a membrane pore-forming domain functionally similar to that of bacterial colicins, flanked by a membrane-addressing domain. In lipid bilayer membranes, apolipoprotein L-I formed anion channels. In Trypanosoma brucei, apolipoprotein L-I was targeted to the lysosomal membrane and triggered depolarization of this membrane, continuous influx of chloride, and subsequent osmotic swelling of the lysosome until the trypanosome lysed.     

FATE AND TRANSPORT OF CONTAMINANT LEAD IN SPODOSOLS: A SIMPLE BOX MODEL ANALYSIS

A dynamic simulation based on a simple box model was made to predict Pb transport in spodosols of the Hubbard Brook Experimental Forest. Simulated results suggest that labile Pb in the forest floor may be undergoing a rapid loss, and that Pb content may reach an equilibrium within ～100 years with a steady-state level of approximately 0.2 kg ha^-1 (concentration = 1.3 μg g^-1). The predicted Pb loss from the forest floor is much higher than the observed Pb export based on zero-tension lysimeters, which are designed to optimize measurement of dissolved substances. It is suspected that lysimeters might have failed to effectively collect particles and colloids. The dissolved Pb²⁺ loss from the forest floor, which is governed by nonlinear retardation, is insignificant relative to total Pb losses, so linear rate removal of particles and colloids from the forest floor is an adequate approximation of Pb transport. The mineral soil is currently acting as a net sink for the Pb released from the forest floor. The model suggests that Pb content in and Pb output from the mineral soil has been increasing since the 1970s. This increase should continue until a steady-state is reached in about 100 years. Unlike the forest floor, the mineral soil loses its Pb via dissolved forms that are regulated by nonlinear adsorption/desorption retardation.     

Plant water deficit effects on Aroostook County potato yields over 30 years 1

We estimated potential irrigation requirements for potato production in Aroostook County, Maine. These requirements were computed from a Plant Water Deficit (PWD) index based on readily available streamflow and climatic parameters. Actual evapotranspiration (AET) figures for specified time periods were assumed to equal the differences between rainfall and runoff. Runoff was computed from differences between streamflow and baseflow for the Aroostook River. Potential evapotranspiration (PET) was computed by the Thomthwaite method. The PWD was established as the difference between PET and AET. The yearly PWD index was then equal to the accumulation of 5-day average values for the PET-AET for each of 30 years of data. Similar computations were made for 10-and 20-day intervals. A yearly temperature index based on Growing Degree Day (GDD) units was also computed. Potato yields were then compared to PWD and GDD values. Results show PWD figures ranging from 11.74 cm to 25.78 cm. There was a highly significant negative correlation existing between PWD and potato yield.     

Fibrous mini-collagens in hydra nematocysts

Nematocysts (cnidocysts) are exocytotic organelles found in all cnidarians. Here, atomic force microscopy and field emission scanning electron microscopy reveal the structure of the nematocyst capsule wall. The outer wall consists of globular proteins of unknown function. The inner wall consists of bundles of collagen-like fibrils having a spacing of 50 to 100 nanometers and cross-striations at intervals of 32 nanometers. The fibrils consist of polymers of "mini-collagens," which are abundant in the nematocysts of Hydra. The distinct pattern of mini-collagen fibers in the inner wall can provide the tensile strength necessary to withstand the high osmotic pressure (15 megapascals) in the capsules.     

Usefulness of AFLP markers to estimate varietal homogeneity of rapeseed inbred line varieties in the context of plant registration and protection

The ability of AFLP markers to assess the uniformity of rapeseed inbred line varieties was investigated in the context of plant registration. Three candidate varieties were chosen on a scale of morphological heterogeneity in the field. Thirty rows per variety were characterized with 4 primer combinations (173 markers). Principal component analysis and distribution of pairwise Rogers' distances between rows revealed exactly the same off types as those observed in the fields. The Nei's genetic diversity computed from the binary data matrix revealed the same diversity level as the one observed with morphological traits: the Nei's diversity value for the most homogeneous variety, a microspore-derived doubled haploid line, was 0.0011, whereas the value for the most heterogeneous variety was 0.0706. The similarity between the results with AFLP markers and morphological traits showed that AFLP markers associated with adapted data analysis tools (PCA, Nei's diversity index, genetic distance distribution) are very useful to assess the uniformity of candidate varieties in the context of plant registration. This revised version was published online in July 2006 with corrections to the Cover Date.     

Transformation and binding of 13C and 14C-labelled atrazine in relation to straw decomposition in soil

As a source of organic matter, crop residues affect the behaviour of pesticides in agricultural soils. The fate of [U‐ring‐¹³C] and [U‐ring‐¹⁴C] atrazine (6‐chloro‐N‐ethyl‐N‐isopropyl‐1,3,5‐triazine‐2,4‐diamine) was investigated during laboratory incubation under controlled conditions in a loamy soil amended with wheat straw at two different states of decomposition: no preliminary decomposition or 6 months’ preliminary decomposition. After 3 months, non‐extractable, so‐called ‘bound’, ¹³C‐atrazine residues were recovered in three particle‐size fractions (> 200, 50–200 and < 50 μm), and investigated with solid‐state ¹³C‐NMR spectroscopy. Parallel incubations with [U‐ring‐¹⁴C] atrazine were carried out to quantify the bound residues as well as the extractable and mineralized fractions. The effect of straw residues on atrazine behaviour depended on whether they had been previously decomposed or not. When straw was decomposed for 6 months prior to incubation, atrazine mineralization was enhanced to 50% of the initial ¹⁴C in contrast to 15% of the initial ¹⁴C in soil alone and soil amended with fresh straw. In parallel, atrazine bound residues were formed in greater amount representing up to 20% of the initial ¹⁴C. CP/MAS ¹³C‐NMR on soil size fractions of soil–straw mixtures after incubation with ¹³C‐atrazine showed that bound residues contained mostly triazinic C, corresponding to atrazine or primary metabolites. Non‐humified organic materials recovered in size fractions > 200 and 50–200 μm contained significant amounts of bound residues, especially when straw was added to the soil. CP/MAS ¹³C‐NMR analysis of humic acids obtained from < 50‐μm fractions was difficult due to overlapping of the native carboxyl ¹³C signal with the ¹³C‐atrazine signal.     

Effect of Planting Date on Time and Rate of Nitrogen Accumulation by Maize (Zea mays L.)1

Effects of environment on time and rate of nutrient accumulation by crops affects fertilizer nutrient use efficiency. The effect of planting date on rate, time and amount of nitrogen (N) accumulated by maize from a Hamerly cl soil (Aeric Calciaquoll) was examined with and without supplemental irrigation. Maize was planted on three dates spaced at 2-to 3-week, intervals; the earliest planting date was 1 May in 1984 and 1985. N accumulation was examined as uni- and diphasic tanh[k(time)] functions and solved for total N accumulation at harvest, time of maximum N accumulation rate and the time coefficient of N accumulation. A diphasic function, which indicates two periods of intense N accumulation, provided the closest agreement with observed N accumulation. As planting was delayed, time required to reach maximum N accumulation rates, τ (uniphasic) or τ₁ and τ₂ (diphasic), decreased from an average of nearly 75 to 42 days (uniphasic) and from nearly 65 to 35 days and 100 to 75 days after planting for τ₁ and τ₂, respectively. Maximum N accumulation rates increase from about 59 to 75 mg N plant^?1 day^?1 (uniphasic) or 35 to 65 mg N plant^?1 day^?1 and 20 to 70 mg N plant^?1 day^?1 for the first and second maxima in the diphasic model, respectively. Average maximum total N accumulation ranged from 2.85 g N plant^?1 for early plantings to 1.5 g N plant^?1 for plantings made on 25 June. The time coefficient, k (uniphasic) or k₁ (diphasic), tended to increase from average values of about 0.04 to > 0.09 day^?1 for k and from about 0.04 to > 0.105 day^?1 for k₁. The second time coefficient, k₂, of the diphasic function varied widely between about 0.075 to > 0.12 day^?1 and showed complex relationships with planting date. Periods of N accumulation shortened and intensity of N accumulation increased as the time coefficient increased.