Mixture interaction analysis: a polynomial model for multiple-receptor systems which incorporates the Beidler equation

A multiple-receptor model for analysis of mixture interactionsis proposed. This model is polynomial, removing the possibilityof predicted responses exceeding the maximum response of a system.The Beidler equation for the kinetics of response to singlecomponents was incorporated into the polynomial model, providinga model for multiple-receptor systems using the same parametersas for the Beidler single-receptor mixture model. The predictionsof the polynomial and the conventional multiple-receptor modelsare similar only at lower response levels. A mixed model isalso proposed which provides for responses to mixtures in whichsome components compete for the same receptor and other componentseach bind to independent receptors.     

Wound healing in tadpole tailfin pieces in vitro.

Explants of tail fins from R. catesbeiana tadpoles undergo reepithelialization of their cut surfaces (healing) when cultured in vitro in Hanks' balanced salt solution at 22 degrees C. Healing is initiated early and closure of the wound is complete by 12 to 24 hours. Morphogenesis continues for several days as further reorganization and migration of epidermal cells from the regions adjacent to the wound margins take place. The addition of serum to the culture media improves the general appearance of these tissues and promotes healing. The rate of healing is affected by temperature. Tail fins maintained at 10 degrees C do not heal while fins maintained at 30 degrees and 37 degrees, although healing more rapidly than at 22 degrees, undergo progressive degeneration in culture. Epidermal cell movements were also studied in explants consisting of a combination of intact tail fin plus tail fin deprived of its epithelium. Rapid and extensive migration of epidermal cells from the intact tail fin across the collagen lamella of the stripped fin is observed.     

Identification of pathogenic fungi in surgical and autopsy specimens by immunofluorescence

Summary A method is presented for the preparation of immune sera and detection by immunofluorescence ofC. immitis, S. schenckii, B. dermatitidis, C. neoformans, andC. albicans in surgical and autopsy material. Formalin fixation does not affect the antigens of the mycotic agents. There are no cross reactions except withC. immitis andC. neoformans, which can be differentiated by the site of the specific fluorescence in each organism.     

EDC3 phosphorylation regulates growth and invasion through controlling P‐body formation and dynamics

Regulation of mRNA stability and translation plays a critical role in determining protein abundance within cells. Processing bodies (P‐bodies) are critical regulators of these processes. Here, we report that the Pim1 and 3 protein kinases bind to the P‐body protein enhancer of mRNA decapping 3 (EDC3) and phosphorylate EDC3 on serine (S)161, thereby modifying P‐body assembly. EDC3 phosphorylation is highly elevated in many tumor types, is reduced upon treatment of cells with kinase inhibitors, and blocks the localization of EDC3 to P‐bodies. Prostate cancer cells harboring an EDC3 S161A mutation show markedly decreased growth, migration, and invasion in tissue culture and in xenograft models. Consistent with these phenotypic changes, the expression of integrin β1 and α6 mRNA and protein is reduced in these mutated cells. These results demonstrate that EDC3 phosphorylation regulates multiple cancer‐relevant functions and suggest that modulation of P‐body activity may represent a new paradigm for cancer treatment.     

Quantitative analysis of lidocaine hydrochloride delivery by diffusion across tissue expander membranes.

Permeability of Silastic tissue expander shells to lidocaine was studied to investigate the feasibility of intraluminal lidocaine injection for pain relief during soft-tissue expansion. Both intact expanders and an apparatus using isolated Silastic membrane segments were used to partition solutions of various lidocaine concentrations, and the rate of diffusion was quantitatively measured using a fluorescence polarization immunoassay. Lidocaine flux was found to follow Fick's law of passive diffusion with respect to time, surface area, and concentration gradient for the first 9 hours, with a permeability coefficient of 10.3 +/- 2.6 micrograms (h.cm2.percent)-1 (mean +/- SD) and diffusion coefficient of 7.5 x 10(-7) cm2/min for an average membrane thickness of 473 +/- 23 microns. After 9 hours, the lidocaine flux decreased exponentially, although the concentration gradient across the membrane remained essentially the same order of magnitude. Plasma proteins in the outer bathing solution and methylparaben used as a preservative in the standard lidocaine formulation had no influence on the change in transport flux with time. At the end of the linear portion of the diffusion curve, less than 2 percent of the total intraluminal lidocaine had crossed the membrane. Potential toxicity in the event of implant rupture limits the maximum total lidocaine dose to approximately 500 mg within an expander at any one time. Within these limits, the capacity for lidocaine delivery of 500 mg lidocaine by a 640-cc tissue expander would be only 6 mg during the first 9 hours after administration.(ABSTRACT TRUNCATED AT 250 WORDS)     

Vegetation and hydrology stratification as proxies to estimate methane emission from tidal marshes

Biogeochemistry - Direct measurement of methane emissions is cost-prohibitive for greenhouse gas offset projects, necessitating the development of alternative accounting methods such as proxies....