Selective trace level analysis of phenolic compounds in water by flow injection analysis--membrane introduction mass spectrometry.

Flow injection analysis coupled with membrane introduction mass spectrometry (FIA-MIMS) with on-line derivatization is shown to allow fast, accurate, nearly interference-free, and sensitive (low microgram/L) quantitation of phenolic compounds in water. On-line FIA derivatization of the phenolic compounds is performed by acetic anhydride acetylation in a K2CO3-buffered alkaline medium. The phenol acetates so formed efficiently permeate a silicone membrane and are directly transferred to the mass spectrometer, in which they are analyzed with selectivity and high sensitivity via selected ion monitoring. FIA-MIMS analysis was performed for aqueous solutions of phenol, 2-methylphenol, 4-chlorophenol, 4-chloro-3-methylphenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol, and detection limits in the 0.5-20 micrograms/L (ppb) range were observed for an analytical frequency of six samples/h. FIA-MIMS for phenolic compound analysis is considerably less time-consuming and labor intensive than most chromatographic methods based on liquid-liquid extraction and preconcentration procedures and is therefore applicable for on-line and in-situ monitoring of phenols in wastewaters and in the environment. FIA-MIMS employing acetic anhydride derivatization is also virtually free of interferences since it combines chemical, membrane, and enhanced MS selectivity; hence quantitation of phenolic compounds can be performed in the presence of congeners.

Potential operator exposure to procymidone in greenhouses.

Recent legislation in the European Union requires regulators of member states to carry out risk assessments using data for actual or potential operator exposure, or estimates of exposure from models. However, the existing models have few datasets from studies carried out on greenhouse or indoor crops, particularly in southern Europe. In this study potential dermal and inhalatory exposures were measured in two trials in Italian greenhouses. The total potential dermal operator exposure of the applicator, measured with a whole-body passive dosimetry method, was 15.4 and 37.1 mL/h of the diluted pesticide mixture. The majority of the contamination was on the hands and on the lower part of the coverall. Approximately 0. 003% of the active ingredient (ai) applied to the crop area contaminated the coverall worn by the operator. The potential dermal exposure during the mixing and loading phase accounted for 6-8% of the total potential dermal exposure during the whole process. Inhalation exposure accounted for only 0.05-0.07% of the total potential operator exposure. Model predictions of the potential operator exposure using a modified version of the German model overestimate the mixing-loading exposure while underestimating the application exposure. These data are evidence that the estimation coefficient set for hand-held application to ornamental and horticultural crops may be inadequate for the agronomic conditions of southern Europe.

All-trans retinoic acid (ATRA)-induced apoptosis is preceded by G1 arrest in human MCF-7 breast cancer cells.

In this study the effects of all-trans retinoic acid (ATRA) on cell cycle and apoptosis of MCF-7 human breast cancer cells were investigated to elucidate the mechanisms underlying the antineoplastic potential of this retinoid in breast cancer. The antiproliferative effect of ATRA was evaluated by DNA content measurements and dual-parameter flow cytometry of bromodeoxyuridine (BrdU) incorporation and of the expression of cell cycle-related proteins (Ki-67 as proliferation marker and statin as quiescence marker) vs DNA content. Apoptosis was also studied by flow cytometry of either DNA content or Annexin V labelling. After 10(-6) M ATRA treatment, the fraction of S-phase cells decreased significantly, and cells accumulated in the G0/G1 range of DNA contents. Dual-parameter flow cytograms showed a decrease in the percentage of Ki-67-labelled cells (after 10 days, only 20% of the cells were still positive for Ki-67 compared with 95% in controls), while the fraction of statin-positive cells increased slightly. From 3 days of treatment onwards, apoptosis was found to occur. These results show that ATRA-induced inhibition of MCF-7 cell growth is related to two mechanisms, i.e. the block of cell proliferation, mostly in a pre-S phase, and the induction of apoptosis. These results should be taken into account when attempting to design treatment programmes that associate ATRA with antineoplastic compounds of different cell cycle specificity.

Cell proliferation in developing human dental pulp. A combined flow cytometric and immunohistochemical study.

Information concerning cell proliferation and differentiation in dental pulp may be important to understand tooth response to exogenous stimuli. Since few data concerning human dental pulp are available, we have investigated the growth fraction and the localization of proliferating cells in pulp tissue of third molars of young adult human males and females, using flow cytometry and immunohistochemistry. Flow cytometric analysis demonstrates a low proliferative activity of pulp tissue that appears to be confined to radicular pulp, as revealed by immunohistochemical detection of proliferating cells. No polyploid or aneuploid cell populations could be identified, and G2-blocked cells, if any, represented a negligible cell population. Odontoblasts, cells of the sub-odontoblastic layer, and cells of coronal pulp were found to be not proliferating under normal conditions. These data provide the basis for future investigations on proliferative activity and regenerative potentiality of human pulp cells in experimental and clinical situations.

Sequential administration of interleukin-3 and granulocyte-macrophage colony-stimulating factor following intensified, accelerated CEE (cyclophosphamide, epirubicin, etoposide) chemotherapy in patients with solid tumors.

The biological mechanisms by which the association of interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) is expected to effectively reduce the hematological toxicity associated with chemotherapy (CT) are not completely elucidated. We exploited the cell kinetic changes of the bone marrow CD34(+) cell subset after CT followed by the IL-3+GM-CSF together with the clinical effects of this association. Eighteen patients with advanced cancers and normal hematopoiesis were treated with an intensified CT course (mg/m(2): CTX 1100, epirubicin 100, VP-16 200; iv day 1). Six cycles were planned at 14-day intervals with the support of IL-3 (5 mu g/kg/day; from day 2 to 6) sequenced with GM-CSF (same dose; from day 7 to 11). DNA content and bromodeoxyuridine incorporation were evaluated using flow cytometry on immunomagnetically-sorted bone marrow CD34(+) cells, at baseline and at different times (days 5, 6, 7, 8, 11 and 14) after CT followed by IL-3+GM-CSF. Treatment with IL-3 induced a marked increase in the % of myeloid precursors with respect to the baseline and in the % of CD34(+) cells in S-phase. However, while the first parameter remained elevated until day 14, the enhanced proliferative activity of the CD34(+) cell subset decreased after IL-3 was stopped and remained significantly low during GM-CSF administration. These data suggest a negative rebound effect on CD34(+) cell proliferation after IL-3 discontinuation which is maintained during GMCSF, that led to kinetic refractoriness of the hyperplastic marrow. In the 99 courses completed a rapid neutrophil and platelet recovery was obtained without cumulative multilineage toxicity. The modifications of CD34(+) cell cycling after CT followed by IL-3+GM-CSF could provide additional myeloprotection during multicyclic, dose-intensive programs.