Depletion of Host-Derived Cyanide in the Gut of the Eastern Tent Caterpillar, Malacosoma americanum

Using a colorimetric procedure, we assessed the HCN-p of black cherry leaves (Prunus serotina) ingested by the eastern tent caterpillar, Malacosoma americanum, and the cyanide content of the bolus as it passed thorough the caterpillar's digestive tract and into the detritus pool. The mean HCN-p of leaves in our study area was 1902 ± 174 (SE) ppm. Young leaves found at the tips of growing branches, which the caterpillars preferred, had a significantly higher HCN-p (3032 ± 258 ppm) than older leaves found at the middle (1542 ± 243 ppm) or base of the shoot (1131 ± 159 ppm). Following a bout of overnight feeding on young leaves, the cyanide content of the foregut and midgut boluses of early sixth-instar caterpillars averaged 631 ± 161 ppm, and 14 ± 3 ppm, respectively, indicating that host-derived cyanide is rapidly depleted as the bolus transits the gut. Some cyanide, however, remains. In three studies, the mean cyanide content of fresh fecal pellets ranged from approximately 20 to 38 ppm, while the dried, compacted pellets ranged from 63 to 85 ppm. Food in the foreguts of mature caterpillars dispersing over the ground in search of pupation sites had 417 ± 99 ppm cyanide. The potential impact of this egested and caterpillar-transported cyanide on the consumer and detritivore communities is discussed.     

Real-time diode laser measurements of vapor-phase benzene

An absorption spectrometer equipped with a IV-VI semiconductor tunable mid-IR diode laser was used to make sensitive measurements of benzene (C(6)H(6)) gas in the 5.1-microm spectral range. Wavelength modulation coupled with second-harmonic detection achieved accurate real-time quantification of benzene concentrations down to a minimum detection limit of 1 ppmv with an integration time of 4 s. A variety of calibrated benzene-sensing measurements were made, including the determination of the benzene concentrations in vehicle exhaust and headspace vapors from unleaded gasoline and other liquids. Kinetic phenomena, including the monitoring of benzene evaporation and absorption/desorption by granulated activated carbon were observed with the instrument. Measurements were performed that allowed experimental determination of the activation energy for desorption of benzene from activated carbon, which was found to be 198 meV/molecule (19.0 kJ/mol).     

Phase I and pharmacokinetic study of oral UFT, a combination of the 5-fluorouracil prodrug tegafur and uracil

UFT is an oral preparation combining the 5-fluorouracil (FU) prodrug tegafur (FT) and uracil (U) in a 1:4 ratio, which is commercially available in Japan for the treatment of breast and gastrointestinal cancers. We sought to determine the tolerance of daily oral UFT and to relate this tolerance to the pharmacokinetics of FT and/or the derived FU, while exploring the possibility of circadian FU kinetics contributing to the results. A 28-day schedule followed by 2 weeks rest was began at the initial level of 300 mg/m2/day administered either at 8 a.m. or at 6 p.m. At the following level, 400 mg/m2/day patients were randomly assigned to a split-dose administration or to the above single, timed dose administration. Intolerance to single dosing was clearly demonstrated, and only the split dosing was advanced to 500 mg/m2/day. When this level proved too toxic, 400 mg/m2 was studied further on a 7 a.m., 3 p.m., and 11 p.m. (every 8 h) schedule. Pharmacology was determined on selected patients. In the single dose administration, areas under the curves of FU were higher following p.m. dosing, although substantial interpatient variation was present. Toxicities (diarrhea and neutropenia) were more severe in patients receiving the drug in single daily doses. We conclude that the kinetics of FT are saturable, with disproportionate increases in area under the curve (and toxicities) as dose levels are increased. With divided dosing, tolerance improves. UFT at a dose of 400 mg/m2/day administered as three divided doses (every 8 h) is suitable for Phase II studies, although toxicity requiring cessation of drug administration prior to completion of 28-day cycles will occur in some patients.     

Angiotensin-converting enzyme gene polymorphism in non-insulin dependent diabetes mellitus and its relationship with diabetic nephropathy

The effects of prolactin (PRL) on proliferation of cultured human uterine leiomyoma-derived smooth muscle cells (SMC) and its mechanism of action were investigated. PRL stimulated DNA synthesis and the expression of PRL receptor was identified by ribonuclease protection assay. Moreover, the regulation of mitogen-activated protein (MAP) kinase by PRL in leiomyoma-derived SMC was investigated. PRL stimulated MAP kinase activity, as detected by 32P incorporation into MAP-2, in a dose-dependent manner. PRL also rapidly stimulated MAP kinase phosphorylation as detected by in vivo phosphorylation using 32P labeling and phosphotyrosine immunoblotting. These results suggest that PRL stimulates the proliferation of human leiomyoma cells via the MAP kinase cascade.     

Laparoscopic evaluation of liver disease in chronic renal failure prior to renal transplantation

It is not rare that controversial indications about the presence or the expression level of multidrug-resistant (MDR) proteins come out from different laboratories upon examination of identical tumor specimens. Distinct aspects, including the use of weakly discriminating monoclonal antibodies (MAbs) and/or unsuitable techniques and procedures, contribute in generating differences in the MDR phenotype evaluation of cancer cells. In this regard we describe here an innovative immunohistochemical approach for the determination of P-glycoprotein expression in cells and tissues. The method is based on the ability of phage-displayed peptides to mimic antibody epitopes. For this purpose we utilized the phage clone #55, which was affinity-purified from a phage-displayed random-peptide library using the MAb MM4.17 (specific for MDR1-P-glycoprotein) as previously described. This clone has been chosen since it clearly and undoubtedly reacts with its cognate MAb, as was determined by ELISA and dot blot tests. Inhibition of the MAb MM4.17 binding to MDR1-P-glycoprotein-expressing cells could be performed by adding a calibrated concentration of phage clone #55 particles, which mimic MDR1-P-glycoprotein antigen. This methodology can eliminate misleading interpretations concerning the presence and expression level of MDR1-P-glycoprotein and might well contribute in routine clinical determinations of MDR in tumor specimens, thus contributing to our understanding of the basis of the mechanisms of tumor cell resistance to drugs.     

Interference and the lossless lossy beam splitter

Abstract

By directing the input into a particular mode it is possible to obtain as output all of the input light for a beam splitter which is 50% absorbing. This effect is also responsible for nonlinear quantum interference when two photons are incident on the beam splitter.     

Transmission lines, EMF and population mixing

Draper et al. found that the incidence of childhood leukaemia was slightly elevated for children living at distances of 200-600 m from high-voltage transmission lines. This elevation cannot be explained by EMF exposure and it is suggested that it may be due to population mixing in housing developments which followed the construction of the lines.     

Development of a model of the feedback process within executive coaching.

Recent literature concerning executive coaching consistently points out the need for a better conceptual understanding of the process of coaching. The current paper addresses this need with an emphasis on the role of feedback in executive coaching. Several existing models of the coaching process mention feedback as an important element, but none expand on the role and function of feedback in executive coaching relationships. This paper builds on several existing models of executive coaching and integrates London and Smither's (2002) model of the feedback process to create a model of feedback in executive coaching. (PsycINFO Database Record (c) 2010 APA, all rights reserved)