Amifostine improves the antileukemic therapeutic index of mafosfamide: implications for bone marrow purging

One of the principal challenges of cancer chemotherapy is the relative inability of most anticancer drugs to distinguish between normal and neoplastic tissues. Consequently, a broad range of toxicities are experienced by patients, especially myelosuppression. Amifostine, a phosphorylated aminothiol, increases the selectivity of specific anticancer drugs for neoplastic cells by protecting normal tissues. One potential application of this protector is during bone marrow purging to selectively remove contaminating cancer cells. This study took normal or leukemic marrow from human subjects and evaluated the ability of amifostine to selectively protect normal bone marrow progenitor cells versus leukemic progenitor cells from the cytotoxic effect of mafosfamide. The dose response of mafosfamide amifostine on leukemia colony-forming units or normal marrow progenitor cells was determined and the LD95 was calculated. Amifostine pretreatment resulted in a statistically significant protection of granulocyte-macrophage colony- forming units and erythroid blast-forming units from the toxicity of mafosfamide (P = .031). Thus, amifostine protection of normal marrow progenitor cells allows a higher LD95 concentration of mafosfamide to be used in ex vivo purging. In contrast, amifostine pretreatment increased the cytotoxicity of mafosfamide on the fresh human leukemia progenitor cells (P = .006). The dual effect of amifostine protection of normal marrow progenitor cells coupled with amifostine-induced sensitization of the leukemia cells increases the possible cell-kill of leukemic stem cells. With amifostine pretreatment, at the LD95 concentrations of mafosfamide for marrow progenitor cells, there was an estimated 6 log increase in cell-kill of the leukemia cells. This selective cell-kill offers the potential for lowering the incidence of leukemic relapse, while preserving more normal stem cells for autologous transplantation.     

Cytometric detection of DNA amplified with fluorescent primers: applications to analysis of clonal bcl-2 and IgH gene rearrangements in malignant lymphomas

Follicular lymphomas comprise almost two thirds of the US adult non- Hodgkin's lymphomas (NHL) and are the most common malignancy of B- lineage lymphocytes. Polymerase chain reaction (PCR) protocols have been developed to detect the t(14;18) translocation, which juxtaposes the bcl-2 proto-oncogene to the Ig heavy-chain (IgH) gene in 85% of follicular lymphomas and monoclonal rearrangements of the IgH gene in B- cell NHL that lack bcl-2 rearrangements. We used PCR to amplify bcl-2 and IgH rearrangements in DNA from patients with lymphoproliferative disorders and analyzed the products in parallel by gel electrophoresis and flow cytometry, which detected PCR products incorporating fluoresceinated oligonucleotide primers by sequence-specific capture to oligonucleotide-coated magnetic beads. Overall, flow cytometry was superior to electrophoresis of ethidium-bromide-stained agarose gels for detection of products of nested PCR to detect intergenic rearrangements involving bcl-2 and single primer-pair amplification of clonal rearrangement of IgH. Flow cytometric analysis detected bcl-2 translocations in 12 of 13 CD10+ B-cell lymphomas and clonal IgH rearrangements in 14 of 17 monoclonal B-cell populations. In contrast, analysis by gel electrophoresis detected bcl-2 translocations in only 10 of 13 CD10+ and clonal IgH gene rearrangements in only 9 of 17 monoclonal B-cell populations. Flow cytometric analysis was more sensitive than gel electrophoresis and could detect a 16-fold greater dilution of a bcl-2-amplified product than gel electrophoresis. Similarly, flow cytometry could detect an amplification product when template DNA was diluted 10,000-fold, whereas gel electrophoresis only detected amplification products when template was subjected to dilution between 100- and 1,000-fold. This shows the utility of flow cytometry for the analysis of DNA amplification products incorporating fluorochrome-labeled primers as a rapid, objective alternative to conventional strategies. Because current-generation clinical laboratories emphasize automation, flow cytometric analysis of PCR- amplified products shows increased analytic sensitivity and offers a vehicle for automation of DNA amplification tests.     

Impact of Typical Rather than Nutrient-Dense Food Choices in the US Department of Agriculture Food Patterns

BackgroundThe US Department of Agriculture (USDA) Food Patterns, released as part of the 2010 Dietary Guidelines for Americans, are designed to meet nutrient needs without exceeding energy requirements. They identify amounts to consume from each food group and recommend that nutrient-dense forms—lean or low-fat, without added sugars or salt—be consumed. Americans fall short of most food group intake targets and do not consume foods in nutrient-dense forms. Intake of calories from solid fats and added sugars exceed maximum limits by large margins.ObjectiveOur aim was to determine the potential effect on meeting USDA Food Pattern nutrient adequacy and moderation goals if Americans consumed the recommended quantities from each food group, but did not implement the advice to select nutrient-dense forms of food and instead made more typical food choices.DesignFood-pattern modeling analysis using the USDA Food Patterns, which are structured to allow modifications in one or more aspects of the patterns, was used. Nutrient profiles for each food group were modified by replacing each nutrient-dense representative food with a similar but typical choice. Typical nutrient profiles were used to determine the energy and nutrient content of the food patterns.ResultsModeration goals are not met when amounts of food in the USDA Food Patterns are followed and typical rather than nutrient-dense food choices are made. Energy, total fat, saturated fat, and sodium exceed limits in all patterns, often by substantial margins. With typical choices, calories were 15% to 30% (ie, 350 to 450 kcal) above the target calorie level for each pattern. Adequacy goals were not substantially affected by the use of typical food choices.ConclusionsIf consumers consume the recommended quantities from each food group and subgroup, but fail to choose foods in low-fat, no-added-sugars, and low-sodium forms, they will not meet the USDA Food Patterns moderation goals or the 2010 Dietary Guidelines for Americans.     

石斛类叶鞘的显微鉴定研究

商品石斛的植物来源复杂,规格繁多,外形鉴定较困难。为了准确鉴定石斛的品种,对常作为药用的16种石斛属(Dendrobium Sw)植物的叶鞘进行了显微观察,发现其表皮细胞的形状,大小,所含草酸钙结晶的形状、大小、分布等种间区别较明显,可作为鉴别石斛种类的科学依据之一。本文对金钗石斛D.nobile Lindl。等16种石斛的叶鞘表面特征加以描述,并附主要特征图和检索表。     

5-取代-1-正丁基-3-吡唑烷酮类化合物的合成及抗惊作用的构效关系

1-正癸基-3-吡唑烷酮是一种新的抗惊活性物质。杜明慧、雷小平等相继合成了一系列3-吡唑烷酮类化合物,结果,1-正丙基-5-对氟苯基-3-吡唑烷酮的抗惊作用最强(EP_(50)=14.7 mg/kg)。为了继续研究1位和5位取代基对抗惊活性的影响,我们将前人合成的35个化合物(表1中化合物1～35)进行了Hansch分析得到以下方程: