Correlation between the occurrence of 1H-MRS lipid signal, necrosis and lipid droplets during C6 rat glioma development

The aim of this study was to investigate the possible correlation between the 1H MRS mobile lipid signal, necrosis and lipid droplets in C6 rat glioma. First, the occurrence of necrosis and lipid droplets was determined during tumor development, by a histological analysis performed on 34 rats. Neither necrosis nor lipid droplets were observed before 18 days post-implantation. At later stages of development, both necrosis and lipid droplets were apparent, the lipid droplets being mainly located within the necrotic areas. Using a second group of eight rats, a temporal correlation was evidenced between mobile lipid signal detected by in vivo single-voxel one- (136 ms echo time) and two-dimensional J-resolved 1H MR spectroscopy, and the presence of necrosis and lipid droplets on the histological sections obtained from the brains of the same rats. Finally, spatial distribution of the mobile lipid signal was analyzed by chemical-shift imaging performed on a third group of eight animals, at the end of the tumor growth. The spectroscopic image corresponding to the resonance of mobile lipids had its maximum intensity in the center of the tumor where necrotic regions were observed on the histological sections. These necrotic areas contained large amounts of lipid droplets. All these results suggest that mobile lipids detected in vivo by 1H MRS (136 ms echo time) in C6 rat brain glioma arise mainly from lipid droplets located in necrosis.     

Interference with CD28, CD80, CD86 or CD152 in collagen-induced arthritis. Limited role of IFN-gamma in anti-B7-mediated suppression of disease

We have investigated interference with co-stimulation by administering mAbs towards CD28, CD80, CD86, and CD152 in mice immunized for the development of collagen-induced arthritis (CIA). Anti-CD80 and anti-CD86 treatment inhibited disease score and incidence, whereas anti-CD28 treatment led only to a delayed disease onset. Administration of anti-CD152 had no effect. The CII-specific Ab-response was suppressed by the co-stimulatory blockade, with a stronger effect on IgG1 than on IgG2a. The CII-driven T cell proliferation, on the other hand, was not affected. Furthermore, T cells primed in the presence of either anti-B7 or anti-CD28 produced markedly increased amounts of IFN-gamma in response to CII. To investigate whether this increase in IFN-gamma was related to disease suppression, IFN-gamma-deficient mice were immunized with CII, treated with anti-B7 and followed for the development of arthritis. As in the wild-type mice, administration of anti-B7 to IFN-gamma-deficient mice led to a reduced disease incidence and severity as well as reduced anti-CII IgG titers. Collectively, these data stress the importance of co-stimulation for the delivery of B cell help rather than for production of Th1 cytokines. We also demonstrate that the enhanced production of IFN-gamma observed after B7-blockade is not accountable for the anti-B7 mediated inhibition of CIA.     

Increased Immunostaining of Fibulin-1, an Estrogen-Regulated Protein in the Stroma of Human Ovarian Epithelial Tumors

Fibulin-1, an extracellular matrix protein, is secreted by human ovarian metastatic cancer cell lines under estrogen stimulation. Fibulin-1 expression was quantified by immunohistochemistry and computer-aided image analysis in 44 human ovarian epithelial tumors and 14 normal ovaries. The fibulin-1 staining intensity in proximal stroma, close to the surface of epithelial cells and tumor cells, progressively increased from normal ovaries to serous carcinomas. In all lesions, excluding cystadenomas, fibulin-1 accumulation was higher in proximal stroma than in distant stroma. In situ hybridization demonstrated strong fibulin-1 gene expression in epithelial cells of serous ovarian carcinomas and some cysts. The weak expression of fibulin-1 RNA in some stromal cells of these tumors could not explain the strong fibulin-1 protein accumulation in tumor stroma, which was therefore mostly produced by tumor epithelial cells. In carcinomas, fibulin-1 staining was not correlated with the percentage of estrogen receptor-α (ERα)-stained nuclei but was inversely correlated with the progesterone receptor. However, in cystadenomas and borderline tumors, both fibulin-1 and ERα protein levels increased, in comparison with normal ovaries, suggesting an effect of estrogens in the early steps of tumorigenesis. This fibulin-1 overexpression, demonstrated in vivo in ovarian carcinomas, might be a useful indicator for predicting cancer risk and/or aggressiveness.     

A founder truncating variant in GDF1 causes autosomal‐recessive right isomerism and associated congenital heart defects in multiplex Arab kindreds

The genetic basis of congenital heart malformations associated with disruption of left–right (L–R) asymmetry is broad and heterogenous, with variants in over 25 genes implicated thus far. Of these, deleterious variants in the Growth/Differentiation Factor 1 (GDF1) gene have been shown to cause heterotaxy with varied complex heart malformations of left–right patterning, in 23 individuals reported to date, either in monoallelic or biallelic state. We report three unrelated individuals exhibiting right isomerism with congenital heart defects, each originating from a consanguineous kindred of Arab‐Muslim descent. Using whole exome sequencing, a shared novel homozygous truncating c.608G > A (p.W203*) variant in the GDF1 gene was revealed as the molecular basis of their disease. Subsequently, targeted sequencing of this variant showed full segregation with the disease in these families, with a total of over 15 reportedly affected individuals, enabling genetic counseling, prenatal diagnosis, and planning of future pregnancies. Our findings further confirm the association of biallelic GDF1 variants, heterotaxy and congenital heart defects of left–right patterning, and expand the previously described phenotypic spectrum and mutational profile. Moreover, we suggest targeted screening for the p.W203* variant in relevant clinical circumstances.     

Virus overrides the propensity of human CD40L-activated plasmacytoid dendritic cells to produce Th2 mediators through synergistic induction of IFN-{gamma} and Th1 chemokine production

Depending on the activation status, plasmacytoid dendritic cells (PDC) and myeloid DC have the ability to induce CD4 T cell development toward T helper cell type 1 (Th1) or Th2 pathways. Thus, we tested whether different activation signals could also have an impact on the profile of chemokines produced by human PDC. Signals that induce human PDC to promote a type 1 response (i.e., viruses) and a type 2 response [i.e., CD40 ligand (CD40L)] also induced PDC isolated from tonsils to secrete chemokines preferentially attracting Th1 cells [such as interferon-gamma (IFN-gamma)-inducible protein (IP)-10/CXC chemokine ligand 10 (CXCL10) and macrophage inflammatory protein-1beta/CC chemokine ligand 4 (CCL4)] or Th2 cells (such as thymus and activation-regulated chemokine/CCL17 and monocyte-derived chemokine/CCL22), respectively. Activated natural killer cells were preferentially recruited by supernatants of virus-activated PDC, and supernatants of CD40L-activated PDC attracted memory CD4(+) T cells, particularly the CD4(+)CD45RO(+)CD25(+) T cells described for their regulatory activities. It is striking that CD40L and virus synergized to trigger the production of IFN-gamma by PDC, which induces another Th1-attracting chemokine monokine-induced by IFN-gamma/CXCL9 and cooperates with endogenous type I IFN for IP-10/CXCL10 production. In conclusion, our studies reveal that PDC participate in the selective recruitment of effector cells of innate and adaptive immune responses and that virus converts the CD40L-induced Th2 chemokine patterns of PDC into a potent Th1 mediator profile through an autocrine loop of IFN-gamma.     

Diagnostic utility of a p63/alpha-methyl-CoA-racemase (p504s) cocktail in atypical foci in the prostate.

Prostatic needle biopsy is the preferred method for diagnosing early prostate cancer, providing specific information. In cases of histological cancer mimics, a diagnosis of atypical small acinar proliferation suspected of but not diagnosed as malignancy can be made. In such cases, and in small focus carcinomas, pathologists use 34betaE12, cytokeratin (CK) 5/6 or p63 immunostaining to label basal cells, and alpha-methylacyl-CoA racemase (AMACR/p504s) immunostaining as a positive prostate cancer marker on two distinct slides. However, in cases of small foci, ambiguous lesions might disappear. The purpose of our study was to improve the sensitivity of a cocktail of two antibodies (p63/p504s) with a sample incubation on 260 prostatic specimens, in order to help make a decision in conjunction with standard histology and CK 5/6 immunostaining. We tested 101 small focus prostatic cancers, 104 atypical small acinar proliferation, 19 high-grade prostatic intraepithelial neoplasia, two atypical adenomatous hyperplasia and 34 benign mimics of cancer. After p63/p504s immunostaining, the final diagnoses retained were as follows: 154 prostatic cancers, 14 atypical small acinar proliferation, 30 high-grade prostatic intraepithelial neoplasia, three atypical adenomatous hyperplasia and 62 benign mimics of cancer. To differentiate malignant from benign lesions, we used the criteria of greater sensitivity to p504s/p63 (95%) than to CK 5/6 (57%) or p63 (86%), and higher specificity for p504s/p63 (95%) than for CK 5/6 (88%) or p63 (81%). With the p504s/p63 cocktail, 89% of the ambiguous lesions were classified vs 53% for CK 5/6. Combined use of the two antibodies, one (p504s) as a positive marker and the other (p63) as a negative marker, with a simple immunostaining procedure, may improve diagnostic performance, sensitivity and specificity, leading to a reduction in the risk of false negatives; this technique in cases of atypical small acinar proliferation should reduce the percentage of residual ambiguous lesions and the need for additional biopsies.