Differential induction responses of delta-aminolevulinate synthase mRNAs during erythroid differentiation: use of nonradioactive in situ hybridization.

Expression of mRNAs encoding the erythroid-specific delta-aminolevulinate synthase (ALAS-E) and the nonspecific delta-aminolevulinate synthase (ALAS-N) were examined in murine Friend virus-transformed erythroleukemia (MEL) cells using nonradioactive in situ hybridization. Following dimethyl sulfoxide (DMSO) treatment, ALAS-E mRNA increased markedly, while ALAS-N mRNA did not increase in wild-type MEL cells. In contrast, in a DMSO-resistant clone of MEL cells, ALAS-E was not detectable before and after DMSO treatment. These findings suggest that ALAS-E and ALAS-N mRNAs are under separate controls and that the expression of ALAS-E mRNA is a critical event in erythroid differentiation.     

Introduction of a methoxymethyl side chain into p-phenylenediamine attenuates its sensitizing potency and reduces the risk of allergy induction

The strong sensitizing potencies of the most important primary intermediates of oxidative hair dyes, p-phenylenediamine (PPD) and p-toluylenediamine (PTD, i.e. 2-methyl-PPD) are well established. They are considered as the key sensitizers in hair dye allergic contact dermatitis. While modification of their molecular structure is expected to alter their sensitizing properties, it may also impair their color performance. With introduction of a methoxymethyl side chain we found the primary intermediate 2-methoxymethyl-p-phenylenediamine (ME-PPD) with excellent hair coloring performance but significantly reduced sensitizing properties compared to PPD and PTD: In vitro, ME-PPD showed an attenuated innate immune response when analyzed for its protein reactivity and dendritic cell activation potential. In vivo, the effective concentration of ME-PPD necessary to induce an immune response 3-fold above vehicle control (EC3 value) in the local lymph node assay (LLNA) was 4.3%, indicating a moderate skin sensitizing potency compared to values of 0.1 and 0.17% for PPD and PTD, respectively. Finally, assessing the skin sensitizing potency of ME-PPD under consumer hair dye usage conditions through a quantitative risk assessment (QRA) indicated an allergy induction risk negligible compared to PPD or PTD.     

PREDOMINANT EXPRESSION OF HUMAN Aγ-INCONTRAST WITH β-GLOBIN GENE IN MEL CELLS TRANSFECTED WITH THE CONSTRUCT μLCRAγψβδβ

A cosmid construct μLCRAγψβδβ were induced into mouse erythroleukemia cell lines 585 that expresses murine adult globin only and MEL GM-979 that expresses both murine embryonic and adult globins.Similar patterns of human globin gene expression were displayed in the two MEL cell lines transfected with the construct.Inducible expression of the Aγ-and β-gene was observed during induced cell differentiation.However,the expression level of the Aγ-globin gene is much higher than that of the β-globin gene in either uninduced or induced MEL transformants.No γ to β switching happened in the stable MEL transformants following a continuous culture.The much more effective enhance of the μLCR on the Aγ-globin gene than that on the β-globin gene is resulted probably from the fact that the distance between the LCR and the β-globin gene is much longer than that between the LCR and the Aγ-globin gene in the construct,in comparison with other constructs containing HS2 or μLCR linked to both of γ- and β-globin genes in different order.Two suggestions can be derived from these results:1) A competition between the γ- and β-globin gene for interaction with the LCR may indeed present,but only an enough long distance difference between the LCR to the γ-and to the β-gene can effectively influence the competition;2) Unlike transgenic mice,MEL cells are incapable of reconstructing the regulatory information involved in developmental control when it is provided by a fragment of the β-globin gene cluster with limited length.     

Gene expression of biomarkers of nephrotoxicity in F344 rats co-exposed to melamine and cyanuric acid for seven days

A number of studies have demonstrated that co-exposure to low levels of melamine and cyanuric acid elicits renal toxicity due to the formation of melamine cyanurate crystals in the kidney nephrons. In this work, we investigated if co-exposure of rats to these compounds leads to alterations in the expression of the genes encoding kidney injury molecule 1 (KIM-1), metallopeptidase inhibitor 1 (TIMP1), clusterin, osteopontin, and neutrophil gelatinase-associated lipocalin/lipocalin 2 (NGAL), which have been proposed as urinary biomarkers for nephrotoxicity. Six-week-old male and female F344 rats were fed ad libitum a diet fortified with 0 (control), 7, 23, 69, 229, or 694 ppm melamine and cyanuric acid (co-exposure groups), 1388 ppm melamine, or 1388 ppm cyanuric acid for seven days. Histopathology and clinical chemistry examination indicated marked toxicity only in the animals exposed to the two highest combined doses of melamine and cyanuric acid. Consistent with these observations, quantitative real-time polymerase chain reaction analysis of kidney tissue indicated increased expression of all genes analyzed relative to the control in both male and female rats fed daily with 229 or 694 ppm melamine and cyanuric acid. Exposure to lower levels of both compounds or to the individual compounds did not induce gene expression changes. These data indicate that quantifying the expression levels of the selected biomarker genes constitutes a useful endpoint to assess the combined toxicity of melamine and cyanuric acid in both male and female rats.     

Exogenous wild-type p53 gene improved survival of nude mice injected with murine erythroleukemia cell line through amelioration of hemorheological changes

OBJECTIVES: Previous investigations have shown that human wild-type p53 gene (WTp53) inhibits the growth of leukemia and tumor cells in vitro. In the present study, the authors used nude mice and examined the therapeutic role of p53 gene for erythroleukemia in vivo in the absence of MHC effects. METHODS: The nude mice were injected with murine erythroleukemia cells (MEL), MEL cells transfected with wild-type p53 gene (MEL-W), and MEL cells transfected with mutated p53 gene (MEL-M). Abnormalities were found in the hemorheological and biophysical properties of red blood cells in all 3 groups of animals, but the abnormalities were lesser in degree and later in appearance in MEL-W group than in MEL and MEL-M groups. Furthermore, the nude mice in MEL-W group lived longer than those in MEL and MEL-M groups. RESULTS: The results showed that WTp53 restrained the growth of erythroleukemia cells in vivo and reduced the erythroleukemia tumorigenesis in the microcirculation by improving the hemorheological and biophysical properties of MEL cells, which helped to prolong the life span of nude mice suffering from erythroleukemia. CONCLUSION: These results contribute to our knowledge on the use of wild-type p53 gene for the treatment of erythroleukemia disease.     

308nm单频准分子光治疗寻常性银屑病和掌跖银屑病临床疗效观察

目的:评估308nm单频准分子光局部照射治疗寻常性银屑病和掌跖银屑病的临床疗效及安全性。方法:采用单频准分子光局部照射治疗35例寻常性银屑病和15例掌跖银屑病患者皮损,每周照射1次或2次,每2周评估疗效1次,并记录不良反应。结果:30例寻常性银屑病患者经16次照射,有效率达70%,慢性斑块型疗效较好。15例掌跖银屑病患者经25次照射,有效率为53.3%。单频准分子光局部照射主要不良反应为瘙痒,局部出现红斑,偶有水疱。结论:308nm单频准分子光局部照射治疗寻常性银屑病和掌跖银屑病见效快,疗程短,且不良反应少。