The unique role of dietary l-arginine in the acceleration of peritoneal macrophage sensitivity to bacterial endotoxin

It is known that cells and organisms can indirectly “sense” changes in l-arginine availability via changes in the activity of various metabolic pathways. However, the mechanism(s) by which genes can be directly regulated by l-arginine in mammalian cells have not yet been elucidated. We investigated the effect of l-arginine in the in vivo model of peritoneal inflammation in mice and in vitro in RAW 264.7 macrophages. A detailed analysis of basic physiological functions and selected intracellular signaling cascades revealed that l-arginine is crucial for the acceleration of macrophage activation by bacterial lipopolysaccharide. l-arginine increased the production of reactive oxygen species, nitric oxide, release of Ca²⁺, as well as inducible nitric oxide synthase expression. Interestingly, the effect of l-arginine on macrophage activation was dependent on the phosphorylation of mitogen-activated protein kinases and activity of phospholipase C. In RAW 264.7 cells, l-arginine was shown to modulate the response of macrophages toward lipopolysaccharide via the activation of G-protein-coupled receptors. According to our data, we concluded that l-arginine availability plays a key role in the initiation of intracellular signaling pathways that trigger the lipopolysaccharide-induced inflammatory responses in murine macrophages. Although macrophages are partially stimulated in the absence of extracellular l-arginine, the presence of this amino acid significantly accelerates the sensitivity of macrophages to bacterial endotoxin.     

Acute leukemias of ambiguous lineage in adults: molecular and clinical characterization

Acute leukemias of ambiguous lineage represent a heterogeneous group of rare, poorly characterized leukemias with adverse outcome. No larger studies have yet performed a combined approach of molecular and clinical characterization of acute undifferentiated leukemia (AUL) and biphenotypic acute leukemia (BAL) in adults. Here we describe 16 adults with AUL and 26 with BAL and performed mutational as well as expression studies of genes with prognostic impact in acute leukemia (BAALC, ERG, MN1, WT1, and IGFBP7). AUL showed overexpression of these genes compared to T-lymphoblastic leukemia (T-ALL), B-precursor ALL, and to acute myeloid leukemia (AML). Genotype alterations were not detectable in AUL. BAL samples were characterized by frequent WT1 mutations (18 %) and BCR-ABL translocations (30 %). ALL-based treatment protocols induced complete remissions in 40 % and AML-like therapies in 22 % of AUL/BAL patients. The outcome in both groups was very poor; a long-term survival was only observed in patients undergoing allogeneic stem cell transplantation (SCT). Our findings indicate that AUL and BAL share important molecular and high-risk features of both myeloid and lymphoid leukemias. BAL patients exhibited genetic alterations, which can be targeted therapeutically. Importantly, ALL therapy might be more effective than AML protocols and AUL/BAL patients should be considered for allogeneic SCT.     

Comparative evaluation of the prognostic value of MUC1, MUC2, sialyl-Lewis(a) and sialyl-Lewis(x) antigens in colorectal adenocarcinoma

AIMS: The significance of MUC1, MUC2 and sialylated Lewis blood group antigens as prognostic markers in colorectal adenocarcinoma was investigated in a large series of patients because previous investigations revealed inconsistent results due to unrelated tumour samples from different patient groups and methodological differences. METHODS AND RESULTS: Tissues from 243 patients with colorectal adenocarcinoma were stained immunohistochemically. MUC1 showed a strong immunoreactivity (in more than 35% of the tumour area) in 32.5%, MUC2 in 51.0%, sialyl-Lewis(x) in 67.9% and sialyl-Lewis(a) in 73.7% of the cases, respectively. MUC1 immunoreactivity displayed a significant correlation with tumour progression as reflected by advancing pTNM staging and poor differentiation. MUC2 expression was significantly stronger in mucinous adenocarcinomas. Sialyl-Lewis(x) immunostaining correlated with the extent of lymph node metastasis as well as low cytological differentiation. According to univariate and multivariate analysis (P < 0.0001) only MUC1 reactivity represented a marker of worse survival probability, opposed to the sialylated Lewis antigens that did not exert a predictive value. CONCLUSIONS: According to our data, MUC1 and sialyl-Lewis(x) immunoreactivity exhibit statistically significant correlations with established markers of tumour progression. However, only MUC1 presents as an independent prognostic factor of colorectal adenocarcinoma.     

Estimation of aneuploidy for chromosomes 3, 7, 16, X and Y in spermatozoa from 10 normospermic men using fluorescence in-situ hybridization

Fluorescence in-situ hybridization (FISH) is a fast and efficient method of estimating aneuploidy in human spermatozoa. In this study, we have estimated baseline disomy frequencies in spermatozoa from a group of 10 normospermic men, using stringent scoring criteria. A triple- probe FISH procedure was used for chromosomes 3, X and Y, while a double-probe FISH method was used for chromosomes 7 and 16. A total of 101273 spermatozoa were scored for chromosomes 3, X and Y, resulting in 97.83% haploidy (3X or 3Y), 0.39% disomy (33X, 33Y, 3XX, 3YY or 3XY) and 0.35% diploidy (33XX, 33YY or 33XY). A total of 100760 spermatozoa were scored for chromosomes 7 and 16, giving 98.9% haploidy (716), 0.11% disomy (7716 or 71616) and 0.27% diploidy (771616). Disomy frequencies for individual chromosomes differed (chromosome 3, 0.20%; chromosome 7, 0.05%, chromosome 16, 0.06%; X + Y, 0.19%). The frequency of disomy 3 was significantly higher than disomy 7 (P = 0.019) and disomy 16 (P = 0.022), while the frequency of sex chromosome disomy was significantly higher than disomy 7 (P = 0.0058) and disomy 16 (P = 0.0067), but not disomy 3 (P = 0.73). The disomy and diploidy (0.27- 0.35%) estimates obtained for this normospermic population were generally low and were similar to other recent reports.