Dissymmetric calix[4]arenes: Optical resolution of some conformationally fixed derivatives

Various possibilities to obtain intrinsically chiral calix[4]arenes are discussed. The enantiomers of three 1,3-dietheresters and one monoether compound derived from dissymmetric calix[4]arenes with C₄ symmetry were separated by HPLC using chiral stationary phases and characterized by their CD spectra. © 1993 Wiley-Liss, Inc.     

Enflurane depresses activity of the medullary inspiratory neurons in the cat

The effect of enflurane on the firing activity (spikes/sec) of the inspiratory neurons of the dorsal respiratory group (DRG) of the medulla oblongata was studied in decerebrate, paralyzed, mechanically ventilated cats before and after bilateral cervical vagotomy. Inspiratory neuronal activity, phrenic neurogram, arterial blood pressure, tracheal pressure, and end tidal CO2 concentration were recorded. Cells whose firing activity was in phase with that of the phrenic nerve were considered inspiratory neurons. Administration of 1 and 2% enflurane in oxygen produced gradual, significant, and dose-dependent depression of the cell activity with cervical vagi either intact or severed. Recovery of the cell activity occurred after termination of enflurane administration. In cats with intact vagi, 10 min after introduction of 1 and 2% enflurane, the cell activity (mean +/- SE) expressed as percentage of the control was 70 +/- 6% (P less than 0.05) and 48 +/- 5% (P less than 0.01), respectively. Bilateral cervical vagotomy did not affect the degree of cell depression due to enflurane. Hypercarbia induced by inhalation of 5% CO2 increased cell activity, but it did not block enflurane-induced cell depression, although it reduced it. It may be concluded that enflurane depresses the activity of the inspiratory neurons of the DRG. The results also suggest that the respiratory depressant effect of enflurane has a central component and that the DRG region may serve as a site to mediate the enflurane-induced respiratory depression.     

Mammalian metallothionein in toxicology,cancer, and cancer chemotherapy

The present paper centers on mammalian metallothionein 1 and 2 in relationship to cell and tissue injury beginning with its reaction with Cd²⁺ and then considering its role in the toxicology and chemotherapy of both metals and non-metal electrophiles and oxidants. Intertwined is a consideration of MTs role in tumor cell Zn²⁺ metabolism. The paper updates and expands on our recent review by Petering et al. (Met Ions Life Sci 5:353–398, 2009).     

Hydrolysis of polyphosphates by corn roots

Summary The hydrolysis of seven linear oligomers (P₂, P₃, P₅, P₁₅, P₂₅, P₃₅ and P₆₅) and one cyclic polyphosphate, trimetaphosphate (TMP), by corn (Zea mays) roots was investigated. In these experiments, corn-root homogenate or intact roots were incubated in a polyphosphate solution containing 1 mM polyphosphate or 50 mg P/L, respectively, and the amount of orthophosphate produced was determined. Results showed that the optimal pH value for hydrolysis of P₃, P₅, and TMP by corn-root homogenate was 5.0, whereas for the hydrolysis of P₂, P₁₅, P₂₅, P₃₅ and P₆₅, it was 6.0. The rate of polyphosphate hydrolysis by cornroot homogenate was temperature dependent up to the point of enzyme inactivation (>50°C). Nonsterile intact roots showed higher rates of hydrolysis than sterile roots, especially with P₂. The hydrolysis of all oligomers by sterile and nonsterile intact roots was very slow during the first 18h at 30°C, but increased rapidly after 18h with the oligomers P≦25. The oligomers P₃₅ and P₆₅ were quite resistant to hydrolysis by sterile and nonsterile roots after 48h incubation at 30°C. An experiment with sterile intact roots in pyrophosphate solution suggested that pyrophosphatase was induced in corn roots in the presence of its substrate. The order of hydrolysis rates of the oligomers by intact sterile corn roots was: P₂>P₃>P₅> TMP>P₁₅>P₂₅>P₃₅>P₆₅.     

miRNA Expression Analyses in Prostate Cancer Clinical Tissues

A critical challenge in prostate cancer (PCa) clinical management is posed by the inadequacy of currently used biomarkers for disease screening, diagnosis, prognosis and treatment. In recent years, microRNAs (miRNAs) have emerged as promising alternate biomarkers for prostate cancer diagnosis and prognosis. However, the development of miRNAs as effective biomarkers for prostate cancer heavily relies on their accurate detection in clinical tissues. miRNA analyses in prostate cancer clinical specimens is often challenging owing to tumor heterogeneity, sampling errors, stromal contamination etc. The goal of this article is to describe a simplified workflow for miRNA analyses in archived FFPE or fresh frozen prostate cancer clinical specimens using a combination of quantitative real-time PCR (RT-PCR) and in situ hybridization (ISH). Within this workflow, we optimize the existing methodologies for miRNA extraction from FFPE and frozen prostate tissues and expression analyses by Taqman-probe based miRNA RT-PCR. In addition, we describe an optimized method for ISH analyses formiRNA detection in prostate tissues using locked nucleic acid (LNA)- based probes. Our optimized miRNA ISH protocol can be applied to prostate cancer tissue slides or prostate cancer tissue microarrays (TMA).     

Some Monte Carlo Studies on the Comparison of Several Means Under Heteroscedasticity and Robustness with Respect to Departure from Normality

By using Monte Carlo studies, this paper compares the Welch test, the James test and the Brown-Forsythe test for comparing several means under heteroscedasticity. It appears that all the tests are quite robust with respect to departure from normality. The Brown-Forsythe test is at least as good as the James test and the Welch test; but the differences are so small that the choice is immaterial for practical purposes.     

Probing the interaction of new and biologically active Pd(II) complex with DNA/BSA via joint experimental and computational studies along with thermodynamic,NLO, FMO and NBO analysis

BioMetals - Treatment with transition metal complexes is an efficient method to fight with cancer. Therefore, a new transition metal complex formulated as [Pd(1, 3-pn)(acac)]Cl (pn and acac stand...