The Effect of Antigen Stimulation on the Migration of Mature T Cells from the Peripheral Lymphoid Tissues to the Thymus

Although the maturation and export of T cells from the thymus has been extensively studied, the movement of cells in the opposite direction has been less well documented. In particular, the question of whether T cells which have been activated by antigen in the periphery are more likely to return to the thymus had been raised but not clearly answered. We examined this issue by activating T cells present in the periphery with their cognate antigen, and assessing migration to the thymus. TCR-transgenic cells from OT-I mice (Thy1.2+), which recognise the ovalbumin peptide OVA257–264 in the context of H-2Kb, were transferred into otherwise unmanipulated Thy1.1+ C57BL/6 mice. Recipient mice were injected i.v. with 5 μg peptide (SIINFEKL) approximately 24 hours later. The numbers of donor-derived (Thy1.2+) cells in the thymus and peripheral lymphoid tissue were determined. The results clearly show increased numbers of transgenic cells in the thymus 3 days after antigenic stimulation. However, since numbers of transgenic cells increased in the spleen and LN in about the same proportion, the data do not support the notion that there is highly increased selective migration of activated T cells to the thymus. Rather, they suggest that a sample of peripheral cells enters the thymus each day, and that the mature immigrants detected in the thymus merely reflect the contents of the peripheral T cell pool

Crop Quality Issues from the Drought of 2012

As we approach harvest, the impact of the drought on grain quality is becoming clearer. Corn in many areas to the west and east of Iowa reached maturity earlier. Most of Iowa\u27s corn will be past black layer by Labor Day weekend. Soybeans have stopped and started with late rains, but expect pod count and seed size to be pretty well set by Labor Day as well. Regardless of crop and quality issue, please talk to your crop insurance company before harvest. Some quality issues are covered; others are not. Quality issues are resolved in crop insurance by deducting an additional percentage of actual production before calculating the settlement

Comprehensive Synthesis of Monohydroxy-Cucurbit[n]urils (n=5, 6, 7, 8): High Purity and High Conversions

We describe a photochemical method to introduce a single alcohol function directly on cucurbit[n]urils (n = 5, 6, 7, 8) with conversions of the order 95-100% using hydrogen peroxide and UV light. The reaction was easily scaled up to 1 g for CB[6] and CB[7]. Spin trapping of cucurbituril radicals combined with MS experiments allowed us to get insights about the reaction mechanism and characterize CB [5], CB[6], CB[7], and C13[8] monofunctional compounds. Experiments involving O-18 isotopically labeled water indicated that the mechanism was complex and showed signs of both radical and ionic intermediates. DFT calculations allowed estimating the Bond Dissociation Energies (BDEs) of each hydrogen atom type in the CB series, providing an explanation of the higher reactivity of the "equatorial" C-H position of CB[n] compounds. These results also showed that, for CB [8], direct functionalization on the cucurbituril skeleton is more difficult because one of the methylene hydrogen atoms (H-b) has its BDE lowering within the series and coming close to that of H-c, thus opening the way to other types of free radicals generated on the CB[8] skeleton leading to several side products. Yet CB[5]-(OH)(1) and CB[8]-(OH)(1), the first CB[8] derivative, were obtained in excellent yields thanks to the soft method presented here

Calibration of NIRS Whole Grain Analyzers for Amino Acid Measurement in Corn

In food and feed products, near infrared spectroscopy (NIRS) is used to measure an increasing number of chemical parameters that have traditionally been measured by analytical chemistry. The use of NIRS is driven by its speed and relative low cost, thereby allowing users to accurately measure nutrient components and other factors of interest in a matter of seconds versus several hours or days for traditional lab results. Calibration of NIRS analyzers relies on good representative sample sets and consistent reference chemistry; calibration is, in itself, a painstaking process but, once done, accurate calibrations provide rapid, reliable measurements in daily operations

Update on Local Processing in Iowa: Ethanol and Soybean Processing

Local processing of corn and soybeans in Iowa continues to expand production of food, feed, and fuel products. Opportunities for farmers to sell crops locally to processing plants as well as grain handling facilities are expanding. Iowa farmers are expected to produce in 2007 2,511,000 bu of corn and 443,000 bu of soybeans. With the rapid expansion ofbiofuels production, Iowa has become the national leader in both ethanol and biodiesel production. These two products alone offer markets for 43% of Iowa\u27s corn production and the oil from 42% of Iowa\u27s soybeans. Biodiesel differs from ethanol in that biodiesel uses one of two primary soybean crush products rather than raw grain

Increased Thymic B Cells but Maintenance of Thymic Structure, T Cell Differentiation and Negative Selection in Lymphotoxin-α and TNF Gene-Targeted Mice

TNF, lymphotoxin (LT) and their receptors are expressed constitutively in the thymus. It remains unclear whether these cytokines play a role in normal thymic structure or function. We have investigated thymocyte differentiation, selection and thymic organogenesis in gene targeted mice lacking LTα, TNF, or both (TNF/LTα-/-). The thymus was normal in TNF/LTα-/- mice with regard to cell yields and stromal architecture. Detailed analysis of αβ and γδ T cell-lineage thymocyte subsets revealed no abnormalities, implying that neither TNF nor LT play an essential role in T cell differentiation or positive selection. The number and distribution of thymic CD11c+ dendritic cells was also normal in the absence of both TNF and LTα. A three-fold increase in B cell numbers was observed consistently in the TNF/LTα-/- thymus. This phenotype was due entirely to the LTα deficiency and associated with changes in the hemopoietic compartment, rather than the thymic stromal compartment of LTα-/- mice. Finally, specific Vβ8+ T cell deletion within the thymus following intrathymic injection of staphylococcal enterotoxin B (SEB) was TNF/LT independent. Thus, despite the presence of these cytokines and their receptors in the normal thymus, there appears no essential role for either TNF or LT in development of organ structure or for those processes associated with T cell repertoire selection

Dosing pole recommendations for lymphatic filariasis elimination: A height-weight quantile regression modeling approach

BACKGROUND: The World Health Organization (WHO) currently recommends height or age-based dosing as alternatives to weight-based dosing for mass drug administration lymphatic filariasis (LF) elimination programs. The goals of our study were to compare these alternative dosing strategies to weight-based dosing and to develop and evaluate new height-based dosing pole scenarios. METHODOLOGY/PRINCIPAL FINDINGS: Age, height and weight data were collected from \u3e26,000 individuals in five countries during a cluster randomized LF clinical trial. Weight-based dosing for diethylcarbamazine (DEC; 6 mg/kg) and ivermectin (IVM; 200 ug/kg) with tablet numbers derived from a table of weight intervals was treated as the gold standard for this study. Following WHO recommended age-based dosing of DEC and height-based dosing of IVM would have resulted in 32% and 27% of individuals receiving treatment doses below those recommended by weight-based dosing for DEC and IVM, respectively. Underdosing would have been especially common in adult males, who tend to have the highest LF prevalence in many endemic areas. We used a 3-step modeling approach to develop and evaluate new dosing pole cutoffs. First, we analyzed the clinical trial data using quantile regression to predict weight from height. We then used weight predictions to develop new dosing pole cutoff values. Finally, we compared different dosing pole cutoffs and age and height-based WHO dosing recommendations to weight-based dosing. We considered hundreds of scenarios including country- and sex-specific dosing poles. A simple dosing pole with a 6-tablet maximum for both DEC and IVM reduced the underdosing rate by 30% and 21%, respectively, and was nearly as effective as more complex pole combinations for reducing underdosing. CONCLUSIONS/SIGNIFICANCE: Using a novel modeling approach, we developed a simple dosing pole that would markedly reduce underdosing for DEC and IVM in MDA programs compared to current WHO recommended height or age-based dosing

Superconductivity and Spin Fluctuations in the Electron-Doped Infinitely-Layered High Tc Superconductor Sr0.9_0.9La0.1_0.1CuO2_2 (Tc=42K)

This paper describes the first 63-Cu NMR study of an electron-doped infinitely-layered high Tc superconductor Sr$_0.9$La$_0.1$CuO$_2$ (Tc=42K). The spin dynamics in the normal state above Tc exhibits qualitatively the same behavior as some hole-doped materials with significantly enhanced spin fluctuations. Below Tc, we observed no signature of a Hebel-Slichter coherence peak, suggesting an unconventional nature of the symmetry of the superconducting order parameter.Comment: Invited Paper to SNS-95 Conference (Spectroscopies on Novel Superconductors 1995 at Stanford). Also presented at Aspen Winter Conference on Superconductivity and Grenoble M^2S-HTSC in 199