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Trace-element analysis has been suggested as a tool for the study of migratory connectivity because (1) trace-element abundance varies spatially in the environment, (2) trace elements are assimilated into animals tissues through the diet, and (3) current technology permits the analysis of multiple trace elements in a small tissue sample, allowing the simultaneous exploration of several elements. We explored the potential of trace elements (B, Na, Mg, Al, Si, P, S, K, Ca, Ti, Cr, Mn, Ni, Cu, Zn, As, Sr, Cs, Hg, Tl, Pb, Bi, Th, and U) to clarify the migratory connectivity of shorebirds that breed in North America and winter in southern South America. We collected 66 recently replaced secondary feathers from Red Knots (Calidris canutus) at three sites in Patagonia and 76 from White-rumped Sandpipers (C. fuscicollis) at nine sites across Argentina. There were significant differences in trace-element abundance in shorebird feathers grown at different nonbreeding sites, and annual variability within a...

Motivation: Transcriptional profiling using microarrays can reveal important information about cellular and tissue expression phenotypes, but these measurements are costly and time consuming. Additionally, tissue sample availability poses further constraints on the number of arrays that can be analyzed in connection with a particular disease or state of interest. It is therefore important to provide a method for the determination of the minimum number of microarrays required to separate, with statistical reliability, distinct disease states or other physiological differences. Results: Power analysis was applied to estimate the minimum sample size required for two-class and multi-class discrimination. The power analysis algorithm calculates the appropriate sample size for discrimination of phenotypic subtypes in a reduced dimensional space obtained by Fisher discriminant analysis (FDA). This approach was tested by applying the algorithm to existing data sets for estimation of the minimum sample size required for drawing certain conclusions on multi-class distinction with statistical reliability. It was confirmed that when the minimum number of samples estimated from power analysis is used, group means in the FDA discrimination space are statistically different. Contact: gregstep@mit.edu * To whom correspondence should be addressed.

A method was developed and validated for determination and quantitation of tilmicosin residues in swine, cattle, and sheep edible tissues, as well as chicken fat, skin, and muscle over a concentration range of 0.025 μg/g–20 μg/g. For chicken kidney and liver, the method was validated over a range of 0.060 μg/g–20 μg/g. The tissue sample was extracted with methanol and a C18 cartridge was used for solid-phase extraction cleanup. A reversed phase gradient liquid chromatographic method with detection at 280 nm was used to separate the tilmicosin from matrix components in 30 min run time. The limit of quantitation (LOQ) of the method was 0.025 μg/g for all tested tissues except chicken kidney and liver, for which the LOQ was 0.06 μg/g. Average recoveries for tissue samples ranged from 73 to 98%. Relative standard deviation values ranged from 0.6 to 14.7%.

INTRODUCTION: Patients diagnosed with WHO Grade III Gliomas experience huge variations in overall survival and treatment response. In general, Grade II and Grade IV gliomas behave more predictably. We have attempted to identify factors within grade III gliomas that may better inform clinicians about the prognosis of this heterogeneous group of tumours. METHOD: Retrospective (1988-2013) case note, database, cytogenetic and tissue sample review of patients histologically diagnosed with WHO Grade III Gliomas. Demographics, molecular data (1p19q co-deletion, IDH mutation, Ki67/MIB), percentage of Grade II features and overall survival (OS) was analysed. Mortality was defined as any cause of death within 12, 18, 24, 36, 48 and 60 months of diagnosis. Results were statistically analysed by Kaplan-Meier and Log Rank (Cox Proportional Regression Hazard) Testing (p < 0.05). RESULTS: Patients (n = 158) had a mean age of 46 years (range 6 days-77 years) with 54% male and 46% female. Mean OS was 25.2 months (range 0-125 months). Diagnoses were 78.5% astrocytoma, 9.5% oligoastrocytoma, 10.1% oligodendroglioma and 1.9% other. Debulking (versus biopsy), adjuvant therapy, age 48 months) was better for females. Tissue analysis for percentage Grade II features is ongoing. CONCLUSION: Debulking surgery, adjuvant therapy and age are well-established prognostic indicators. Molecular factors are possibly more weighted factors in predicting tumour behaviour and outcome. Routine availability of molecular genetics and the percentage of Grade II features will likely redefine this group of tumours into subcategories.

A procedure is provided for the determination of mercury in animal tissue using a single unit stationary cold-vapor generator utilizing atomic absorption spectrophotometry. The entire reduction-absorption cell is fitted to the burner mount on the instrument. Sample digests are introduced into the sample compartment along with reductant, and background corrected absorbance is measured after three minutes of sample-reductant mixing. The method is sensitive to 2 ng Hg (0.50 ng/mL Hg at 0.0044 absorbance units), which corresponds to 25 ng Hg per gram wet tissue using the prescribed digestion procedure. Reproducibility and accuracy are comparable to conventional cold-vapor techniques and the fact that relatively small sample aliquots (4.0 mL) are used for analysis provides for multideterminations of Hg in a single tissue digest; this is not ordinarily possible using conventional cold-vapor methods. A total of 15 digested tissue sample can be analyzed per hour. The method is proposed as an alterative to presently used cold-vapor Hg techniques.

Four young (23 kg body weight) and two mature wethers (52 and 92 kg body weight) were subcutaneously injected with hexestrol (HX) or HX dicaprylate (HX-D) and killed 41 d later. The HX residues, comprising free, glucuronide and KOH hydrolyzable forms plus metabolites were determined by gas chromatography after liquid-liquid extraction and silica gel chromatographic purification of tissue sample. The HX residues were observed to be at concentrations of .1 to 1.0 ppb in most of the tissues examined. Maturity of the animals and the two hormonal formulations resulted in little difference in residues. The KOH hydrolyzable fraction was hardly detected in the tissues examined. Free HX was a major residue in muscle, representing about 70% of HX residues. Glucuronide HX represented 70 to 80% of HX residues in liver and kidney. In lung, glucuronide and free HX were present in similar amounts. This study showed that the gross metabolic patterns of HX and its esters are similar to other estrogens and steroids.

A gas-liquid chromatographic assay has been developed to determine major residues of morantel in bovine liver, a target tissue, at levels of 0.2-0.8 ppm. The method is based on hydrolysis of the N-methyltetrahydropyrimidine portion of morantel and its metabolites to N-methyl-l,3-propanediamine, and conversion of the diamine to an N,N'-bis-(2-nitro-4-trifluoromethylphenyl) derivative. The addition of an internal standard, N-ethyl-l,3-propanediamine, to the tissue sample circumvents any potential problem that could arise from variable reaction yields, and eliminates the true recovery as a factor affecting the accuracy and precision of the procedure. The concentrations of the, derivatives are determined by pulsed electron capture gas-liquid chromatography over a linear dynamic range equivalent to 0.2-0.8 ppm morantel. The method has been evaluated at 0, 0.2,0.4, and 0.8 ppm levels in fortified bovine liver, and in a withdrawal sample containing physiologically incurred morantel residues. Mean values of 0.22 ± 0.015,0.40 ± 0.033, and 0.79 ± 0.045 ppm were found for fortified samples, 0.02 ppm for control liver, and 0.56 ± 0.050 ppm for the withdrawal sample.

Five dairy cows were fed Rabon® insecticide (2-chloro-1-(2,4,5-trichlorophenyl) vinyl dimethyl phosphate) at levels ranging between 36-252 ppm of an air-dry ration (during an entire gestation period. One of the cows was carried through an additional gestation period. Milk residues were generally nondetectable (