Prognostic impact of B-cell density in cutaneous melanoma

Studies on the prognostic importance of tumor-infiltrating lymphocytes have mainly focused on T cells, while little is known about the role of tumor-infiltrating B lymphocytes. We investigated the prevalence of CD20⁺ B cells by immunohistochemistry in primary melanoma samples of 106 patients and analyzed in relation to clinicopathological parameters and patients’ survival. The majority of samples contained a significant amount of B lymphocytes, predominantly dispersed in the stroma surrounding tumor deposits (mean peritumoral and intratumoral densities: 178.7 ± 156.1 vs. 4.9 ± 6.9 cells/mm², respectively). B cells organized in follicle-like aggregates were also observed in 26% of the samples. B-cell density correlated with that of activated (CD25⁺ or OX40⁺) T lymphocytes. Infiltration by CD20⁺ lymphocytes did not correlate with tumor thickness, while the presence of B-cell aggregates was observed more frequently in thick melanomas. On the other hand, B-cell infiltration was more pronounced in nonmetastatic or lymph node metastatic tumors, compared to visceral metastatic ones. Accordingly, high number of these cells provided significant survival advantage (P = 0.0391 and P = 0.0136 for intra- and peritumoral infiltration, respectively). Furthermore, combination of peritumoral B-cell density with the number of activated T lymphocytes identified patient subgroups with different disease outcome, which was most favorable in the case of high density, while very poor in the case of low density of both cell types. Multivariate survival analysis identified tumor thickness and CD20⁺/OX40⁺ cell density combination as significant independent prognostic factors. Taken together, our results show correlation between low number of CD20⁺ B lymphocytes and melanoma progression, indicating a possible role of tumor-infiltrating B cells in antitumoral immune response. It was also reflected in better outcome of the disease since the density of B lymphocytes alone as well as in combination with that of activated T cells proved of prognostic importance in patients with malignant melanoma.     

How does hydroxyl introduction influence the double helical structure: the stabilization of an altritol nucleic acid:ribonucleic acid duplex

Altritol nucleic acids (ANAs) are a promising new tool in the development of artificial small interfering ribonucleic acids (siRNAs) for therapeutical applications. To mimic the siRNA:messenger RNA (mRNA) interactions, the crystal structure of the ANA:RNA construct a(CCGUAAUGCC-P):r(GGCAUUACGG) was determined to 1.96?? resolution which revealed the hybrid to form an A-type helix. As this A-form is a major requirement in the RNAi process, this crystal structure confirms the potential of altritol-modified siRNAs. Moreover, in the ANA strands, a new type of intrastrand interactions was found between the O2' hydroxyl group of one residue and the sugar ring O4' atom of the next residue. These interactions were further investigated by quantum chemical methods. Besides hydration effects, these intrastrand hydrogen bonds may also contribute to the stability of ANA:RNA duplexes.     

Ligand chirality effects on the dynamics of human 3-phosphoglycerate kinase: comparison between D- and L-nucleotides

l-nucleoside analogues are now largely used as antiviral drugs for the treatment of viral infections like HBV, HCV and HIV. However, in order to be fully active, they need to be phosphorylated by cellular or viral kinases. Human 3-phosphogycerate kinase (hPGK) was shown to catalyze the last step of activation of l-enantiomers and thus constitutes an attractive target for theoretical predictions of its phosphorylation efficiency. Molecular dynamics simulations were carried out with four different nucleotides (d-/l-ADP and d-/l-CDP) in complex with hPGK and 1,3-bisphospho-d-glycerate (bPG). The binding affinities of CDPs (both enantiomers) for hPGK were found very weak while d- and l-ADP were better substrates. Interestingly, the binding affinity of the bPG substrate was found to be lower in presence of d-ADP than l-ADP which indicates a potential antagonistic effect on one substrate to the other. A detailed analysis of the simulations unravels important dynamic conditions for efficient phosphorylation. Indeed, as previously described for the natural substrate, the hinge bending motion of the domains upon substrates binding should be more correlated and directional. Interestingly, the unforeseen finding was the larger dynamics freedoms observed for the substrates that was favored by the protein atoms flexibility around the nucleobase binding site.     

Selective perturbation of the myosin recovery stroke by point mutations at the base of the lever arm affects ATP hydrolysis and phosphate release

After ATP binding the myosin head undergoes a large structural rearrangement called the recovery stroke. This transition brings catalytic residues into place to enable ATP hydrolysis, and at the same time it causes a swing of the myosin lever arm into a primed state, which is a prerequisite for the power stroke. By introducing point mutations into a subdomain interface at the base of the myosin lever arm at positions Lys(84) and Arg(704), we caused modulatory changes in the equilibrium constant of the recovery stroke, which we could accurately resolve using the fluorescence signal of single tryptophan Dictyostelium myosin II constructs. Our results shed light on a novel role of the recovery stroke: fine-tuning of this reversible equilibrium influences the functional properties of myosin through controlling the effective rates of ATP hydrolysis and phosphate release.     

Cariprazine (RGH-188), a potent D3/D2 dopamine receptor partial agonist, binds to dopamine D3 receptors in vivo and shows antipsychotic-like and procognitive effects in rodents

We investigated the in vivo effects of orally administered cariprazine (RGH-188; trans-N-{4-[2-[4-(2,3-dichlorophenyl)-piperazin-1-yl]-ethyl]-cyclohexyl}-N′,N′-dimethyl-urea), a D₃/D₂ dopamine receptor partial agonist with ∼10-fold preference for the D₃ receptor. Oral bioavailability of cariprazine at a dose of 1 mg/kg in rats was 52% with peak plasma concentrations of 91 ng/mL. Cariprazine 10 mg/kg had good blood-brain barrier penetration, with a brain/plasma AUC ratio of 7.6:1. In rats, cariprazine showed dose-dependent in vivo displacement of [³H](+)-PHNO, a dopamine D₃ receptor-preferring radiotracer, in the D₃ receptor-rich region of cerebellar lobules 9 and 10. Its potent inhibition of apomorphine-induced climbing in mice (ED₅₀ = 0.27 mg/kg) was sustained for 8 h. Cariprazine blocked amphetamine-induced hyperactivity (ED₅₀ = 0.12 mg/kg) and conditioned avoidance response (CAR) (ED₅₀ = 0.84 mg/kg) in rats, and inhibited the locomotor-stimulating effects of the noncompetitive NMDA antagonists MK-801 (ED₅₀ = 0.049 mg/kg) and phencyclidine (ED₅₀ = 0.09 mg/kg) in mice and rats, respectively. It reduced novelty-induced motor activity of mice (ED₅₀ = 0.11 mg/kg) and rats (ED₅₀ = 0.18 mg/kg) with a maximal effect of 70% in both species. Cariprazine produced no catalepsy in rats at up to 100-fold dose of its CAR inhibitory ED₅₀ value. Cariprazine 0.02-0.08 mg/kg significantly improved the learning performance of scopolamine-treated rats in a water-labyrinth learning paradigm. Though risperidone, olanzapine, and aripiprazole showed antipsychotic-like activity in many of these assays, they were less active against phencyclidine and more cataleptogenic than cariprazine, and had no significant effect in the learning task. The distinct in vivo profile of cariprazine may be due to its higher affinity and in vivo binding to D₃ receptors versus currently marketed typical and atypical antipsychotics.     

Research blogs and the discussion of scholarly information

The research blog has become a popular mechanism for the quick discussion of scholarly information. However, unlike peer-reviewed journals, the characteristics of this form of scientific discourse are not well understood, for example in terms of the spread of blogger levels of education, gender and institutional affiliations. In this paper we fill this gap by analyzing a sample of blog posts discussing science via an aggregator called ResearchBlogging.org (RB). ResearchBlogging.org aggregates posts based on peer-reviewed research and allows bloggers to cite their sources in a scholarly manner. We studied the bloggers, blog posts and referenced journals of bloggers who posted at least 20 items. We found that RB bloggers show a preference for papers from high-impact journals and blog mostly about research in the life and behavioral sciences. The most frequently referenced journal sources in the sample were: Science, Nature, PNAS and PLoS One. Most of the bloggers in our sample had active Twitter accounts connected with their blogs, and at least 90% of these accounts connect to at least one other RB-related Twitter account. The average RB blogger in our sample is male, either a graduate student or has been awarded a PhD and blogs under his own name.     

Circulating anti-heat-shock-protein antibodies in normal pregnancy and preeclampsia

It has been previously reported that circulating anti-heat-shock-protein (Hsp) antibody levels are elevated in cardiovascular disorders. The aim of the present study was to determine circulating antihuman Hsp60, antimycobacterial Hsp65, and antihuman Hsp70 antibody levels in healthy pregnant women and preeclamptic patients and to investigate their relationship to the clinical characteristics of the study subjects, as well as to the markers of inflammation (C-reactive protein (CRP)), endothelial activation (von Willebrand factor antigen), or endothelial injury (fibronectin), oxidative stress (malondialdehyde) and to serum Hsp70 levels. Ninety-three preeclamptic patients and 127 normotensive healthy pregnant women were involved in this case control study. Serum anti-Hsp60, anti-Hsp65, anti-Hsp70, and Hsp70 levels were measured with enzyme-linked immunosorbent assay (ELISA). Serum CRP levels were determined by an autoanalyzer using the manufacturer’s kit. Plasma von Willebrand factor antigen levels were quantified by ELISA, while plasma fibronectin concentration by nephelometry. Plasma malondialdehyde levels were measured by the thiobarbituric-acid-based colorimetric assay. For statistical analyses, nonparametric methods were applied. Anti-Hsp60, anti-Hsp65, and anti-Hsp70 antibodies were detected in all of our serum samples. There were no significant differences in serum anti-Hsp60, anti-Hsp65, and anti-Hsp70 antibody levels between the control and preeclamptic groups. Serum levels of Hsp70 and CRP, as well as plasma levels of VWF antigen, fibronectin, and malondialdehyde, were significantly higher in preeclamptic patients than in normotensive healthy pregnant women. Serum anti-Hsp60 antibody levels showed significant correlations with serum anti-Hsp65 antibody levels both in the control and the preeclamptic groups (Spearman R = 0.55 and 0.59; p < 0.001, respectively). However, no other relationship was found between clinical features (maternal age, smoking status, parity, body mass index, gestational age at blood draw, systolic and diastolic blood pressure, gestational age at delivery, and fetal birth weight) and measured laboratory parameters of the study subjects and serum anti-Hsp antibody levels in either study group. In conclusion, anti-Hsp60 and anti-Hsp70 antibodies as naturally occurring autoantibodies are present in the peripheral circulation of healthy pregnant women. Nevertheless, humoral immunity against heat shock proteins was not associated with preeclampsia. Further studies are warranted to explore the role of heat shock proteins and immune reactivity to them in the immunobiology of normal pregnancy and preeclampsia.     

Phloroglucinol in plant tissue culture

In plant tissue culture research, there is a constant need to search for novel substances that could result in better or more efficient growth in vitro. A relatively unknown compound, phloroglucinol (1,3,5-trihydroxybenzene), which is a degradation product of phloridzin, has growth-promoting properties. Phloroglucinol increases shoot formation and somatic embryogenesis in several horticultural and grain crops. When added to rooting media together with auxin, phloroglucinol further stimulates rooting, most likely because phloroglucinol and its homologues act as auxin synergists or auxin protectors. Of particular interest is the ability of phloroglucinol—a precursor in the lignin biosynthesis pathway—to effectively control hyperhydricity through the process of lignification, thus maximizing the multiplication rate of woody species and other species that are difficult to propagate. Phloroglucinol has also been used to improve the recovery of cryopreserved Dendrobium protocorms, increasing the potential of cryopreservation for application in ornamental biotechnology. Phloroglucinol demonstrates both cytokinin-like and auxin-like activity, much like thidiazuron, and thus has considerable potential for application in a wide range of plant tissue culture studies.