Research communications in molecular pathology and pharmacology最新文献

To elucidate physiological relevance of the skipping of exon 11 in muscle-type phosphofructokinase (PFK-M) transcripts, we partially cloned and analyzed the cDNA and the genomic fragment of mouse PFK-M. In RT-PCR analysis using a pair of primers which carry the region corresponding to human exon 11 in between, any minor transcript without exon 11 was not detected. Partial sequencing analysis of mouse PFK-M gene revealed that the junctions of intron 10 of human gene were both less identical to the consensus sequences than those of mouse gene, but that there was no appreciable difference in the junctions in intron 11 between mouse and human. These results suggest that the skipping of exon 11 in PFK-M gene transcripts would be found mainly in human. Although further investigation would be required to understand the mechanisms and physiological significance of exon-skipping, the exon-skipping in PFK-M transcripts would be unlikely to have the physiological significance.

The FasL-Fas system has been recognized as one of the apoptosis-inducing systems in the body. We studied the association between the serum levels of sFas, sFasL and TNF-alpha and the severity of the pathophysiological condition in 20 patients with multiple organ dysfunction syndrome (MODS) complicating generalized peritonitis. The serum levels of sFas and TNF-alpha were significantly higher in the patients who died than in those who survived. On the other hand, the sFasL level was significantly higher in the patients who survived than in those who died. A significant correlation was observed between the serum TNF-alpha level and the serum sFas level. These findings suggest that changes in the FasL-Fas system may be involved in the pathogenesis of MODS.

It has been reported that the total body clearance (CL) of 2-(allylthio)pyrazine (2-AP) was significantly faster after intravenous administration of 2-AP to rats pretreated with 3-methylcholanthrene, phenobarbital, and dexamethasone (main inducers of CYP1A1/2, CYP2B1/2, and CYP3A1/2, respectively, in rats) than those in respective control rats. It has also been reported that expression of CYP2E1 and CYP3A1(23) increased 2.3 and 4 times, respectively, in rats with acute renal failure induced by uranyl nitrate (U-ARF) compared with those in control rats. However, CYP1A2 and CYP2B1/2 expression was not changed. Therefore, it could be expected that the pharmacokinetics of 2-AP could be changed in rats with U-ARF due to increase in expression of CYP3A23 in the rats. After intravenous administration of 2-AP at a dose of 50 mg/kg to rats with U-ARF, the area under the plasma concentration-time curve from time zero to time infinity of 2-AP was significantly smaller (1030 versus 1360 microg min/ml) due to significantly faster CL of 2-AP (48.4 versus 36.8 ml/min/kg). This could be due to increased expression of CYP3A23 in rats with U-ARF.

Evidence has shown that N-acetyltransferase (NAT) acetylated 2-aminofluorene (AF) to form N-acetyl-2-aminofluorene (AAF). Then it was metabolized by cytochrome P450 (CYP) enzyme to form ring or N-hydroxylated metabolites. Sulfotransferase and other enzymes participated to form the ultimate metabolites which bind to DNA to form DNA-AF adducts which may have led to cancer development. The aim of the present study is to demonstrate whether paclitaxel (taxol) can inhibit the NAT activity, NAT gene expression and DNA-AF adduct formation in human stomach tumor cell line (SC-M1). The activity of NAT was determined by high performance liquid chromatography (HPLC) assaying for the amounts of acetylated AF (AAF) or p-aminobenzoic acid (N-Ac-PABA) and nonacetylated AF or PABA. While SC-M1 cell cytosols were used for examining NAT activity, intacts cells were used for examining all three: NAT activity, gene expression and DNA-AF adduct formation. As compared with the control group, the paclitaxel- treated group showed decreased NAT activity and DNA-AF adduct formation in SC-M1 cells and the decrease was dose-dependent. The results also indicated that paclitaxel decreased the apparent values of K(m) and V(max) from SC-M1 cells in both cytosol and intact cells. Palitaxel did significantly affect NAT gene expression (NAT1 mRNA) in SC-M1 cells.

The investigations concerning the activity of antimycotic drugs on pathogenic fungi, revealed a decrease of sensitivity of fungi, especially of the Candida species. In other investigations we have stated that strains isolated from patients have other than standard enzymatic activity. So it seems to be interesting to have evaluated the model for analysis in vitro the influence of antimycotic drug for egzoenzyme of fungi. The aims of the study were: 1. estimation of the influence in vitro ketoconazole, which was added everyday for 3 weeks on curves of activity of the drug, on strains isolated from patients; 2. estimation of asparagine protease activity on strains before, during and after the added drug to the culture. During the study we evaluated the model in vitro to obtain strains with lower sensitivity for a antimycotic drug. Everyday during a 3 week period we added to the culture ketoconazole in the concentration of about 2, 4 and 6 times higher than the minimal inhibitory concentration (MIC). Before, 1, 2 and 3 weeks after we investigated the activity of asparaginee protease. We obtained the following results: 1. Ketoconazole added to the culture of Candida strains during 3 weeks had influenced the response curves, which was observed as statistical significant changes between MIC values. 2. Ketoconazole after 1 week of administration decreased and after 2 and 3 weeks increased of asparagine protease activity.

Human immunodeficiency virus-associated nephropathy (HIVAN) is a major complication of HIV infection with distinct pathological features, which may lead to end-stage renal disease. We describe a 32-year-old African man with HIVAN, to whom protease inhibitor-containing antiretroviral therapy was introduced and in whom stability of serum creatinine levels was observed for 60 weeks after the introduction. This report suggests useful application of highly active antiretroviral therapy into the patients with HIVAN to avoid the rapid progression of renal function, although the long-term effect of this therapy needs to be prospectively evaluated in a large number of cases.

Tamoxifen was used to determine the effects of N-acetyltransferase(NAT) activity and 2-aminofluorene (2-AF)-DNA adduct formation in human breast cancer cells. Breast cancer cells were categorized into two groups based on the status of estrogen receptor, ER (+) and ER (-). 2-AF-DNA adduct formations in breast cancer cells are 2.58 +/- 0.39 pmol adduct/mg DNA for ER (+) and 2.74 +/- 0.46 pmol adduct/mg DNA for ER (-), respectively. Co-treatment with 1 microM tamoxifen inhibited DNA-adduct formations up to 65% in ER (+) and 61% in ER (-), respectively. The inhibition of Tamoxifen on DNA adduct formation between ER (+) and ER (-) cell was not significantly different. The results of the N-acetyltransferase activity in human breast cancer cells were inhibited by tamoxifen in a dose dependent manner. Tamoxifen inhibited 50.0% and 42.8% of Km in ER (+) and ER (-), 58.2% and 35.6% of Vmax, respectively. Based on the kinetic study of N-acetyltransferase activity, tamoxifen plays a non-competitive role in the acetylation reaction. This study demonstrates that tamoxifen inhibited not only NAT activity but also DNA-adduct formation in human breast cancer cells, regardless of the status of estrogen receptor. These findings could provide a clue that tamoxifen has chemoprevention effects in breast cancer.

Recent studies suggest the critical role of inflammatory mediators in the genesis and healing of gastric ulcers. Ketoconazole a commonly used anti-fungal agent has a potent immunomodulatory action. The present investigation was undertaken to study the effect of ketoconazole on chemically and stress induced gastric ulcers in rats. Experimental gastric lesions in rats were induced by water immersion restraint stress, indomethacin and ethanol. Acid secretion studies were undertaken in pylorus ligated rats with and without ketoconazole. The level of myeloperoxidase (marker of neutrophil activity) non-protein sulfhydryl compounds and gastric wall mucus were measured after ethanol induced gastric lesions. Ketoconazole treatment resulted in significant protection against stress; indomethacin and ethanol induced gastric lesions in rats. Ketoconazole also dose dependently attenuated ethanol induced increase in myeloperoxidase activity and protected gastric mucosa against ethanol-induced depletion of non-protein sulfhydryl. These findings point towards the mediation of neutrophils and sulfhydryl compounds in ketoconazole induced cytoprotection. In conclusion, this study clearly shows anti-acid secretory, anti-ulcer and cytoprotective activity of ketoconazole.

In this study, we analyzed high expression of protein phosphatase (PP) 2A in Alzheimer's disease brain compared to that of the control brain, which result from hyperphosphorylation of histone H1. PP1alpha and PP1gamma1 were slightly expressed in all cases, but there was no relation to the levels of the phosphate in histone H1.