The G protein-coupled receptor P2RY8 and follicular dendritic cells promote germinal center confinement of B cells, whereas S1PR3 can contribute to their dissemination.

The orphan Gα13-coupled receptor P2RY8 is mutated in human germinal center (GC)-derived lymphomas and was recently found to promote B cell association with GCs in a mouse model. Here we establish that P2RY8 promotes clustering of activated B cells within follicles in a follicular dendritic cell (FDC)-dependent manner. Although mice lack a P2RY8 orthologue, we show that mouse GC B cell clustering is also dependent on FDCs acting to support the function of a Gα13-coupled receptor. Mutations in GNA13 and its downstream effector ARHGEF1 are associated with the development of disseminated GC-derived lymphomas. We find that egress of Gna13 mutant GC B cells from lymph nodes in the mouse depends on sphingosine-1-phosphate receptor-3. These findings provide evidence that FDCs promote GC confinement of both human and mouse GC B cells via Gα13-dependent pathways, and they show that dissemination of Gα13-deficient GC B cells additionally requires an egress-promoting receptor

S-Geranylgeranyl-L-glutathione is a ligand for human B cell-confinement receptor P2RY8.

Germinal centres are important sites for antibody diversification and affinity maturation, and are also a common origin of B cell malignancies. Despite being made up of motile cells, germinal centres are tightly confined within B cell follicles. The cues that promote this confinement are incompletely understood. P2RY8 is a Gα13-coupled receptor that mediates the inhibition of migration and regulates the growth of B cells in lymphoid tissues1,2. P2RY8 is frequently mutated in germinal-centre B cell-like diffuse large B cell lymphoma (GCB-DLBCL) and Burkitt lymphoma1,3-6, and the ligand for this receptor has not yet been identified. Here we perform a search for P2RY8 ligands and find P2RY8 bioactivity in bile and in culture supernatants of several mouse and human cell lines. Using a seven-step biochemical fractionation procedure and a drop-out mass spectrometry approach, we show that a previously undescribed biomolecule, S-geranylgeranyl-L-glutathione (GGG), is a potent P2RY8 ligand that is detectable in lymphoid tissues at the nanomolar level. GGG inhibited the chemokine-mediated migration of human germinal-centre B cells and T follicular helper cells, and antagonized the induction of phosphorylated AKT in germinal-centre B cells. We also found that the enzyme gamma-glutamyltransferase-5 (GGT5), which was highly expressed by follicular dendritic cells, metabolized GGG to a form that did not activate the receptor. Overexpression of GGT5 disrupted the ability of P2RY8 to promote B cell confinement to germinal centres, which indicates that GGT5 establishes a GGG gradient in lymphoid tissues. This work defines GGG as an intercellular signalling molecule that is involved in organizing and controlling germinal-centre responses. As the P2RY8 locus is modified in several other types of cancer in addition to GCB-DLBCL and Burkitt lymphoma, we speculate that GGG might have organizing and growth-regulatory roles in multiple human tissues

Patients with epilepsy and psychogenic non-epileptic seizures: An inpatient video-EEG monitoring study

AbstractSeizure and EEG characteristics of patients with epilepsy and concomitant psychogenic non-epileptic seizures (PNES) were compared to age and sex matched controls with epilepsy alone in a retrospective case control study. 39 patients with clearly documented epileptic and non-epileptic events were compared to 78 age and sex matched controls, sequentially admitted for video-EEG monitoring with documentation of epilepsy alone. Frontal seizures were higher in prevalence in patients with PNES who had concomitant epilepsy (P<0.001), while temporal seizures were higher in prevalence in patients with epilepsy alone (P<0.04). On regression analysis, the odds of having a frontal seizure was found to be significantly lower in the epilepsy alone group compared to the epilepsy+PNES group (odds ratio 0.13, 95% CI, 0.033–0.51). This significant association between frontal lobe epilepsy and PNES may be related to misattribution of frontal seizures for PNES events, or may reflect frontal lobe cortical dysfunction in this subgroup

Hydrofocusing Bioreactor Produces Anti-Cancer Alkaloids

A methodology for growing three-dimensional plant tissue models in a hydrodynamic focusing bioreactor (HFB) has been developed. The methodology is expected to be widely applicable, both on Earth and in outer space, as a means of growing plant cells and aggregates thereof under controlled conditions for diverse purposes, including research on effects of gravitation and other environmental factors upon plant growth and utilization of plant tissue cultures to produce drugs in quantities greater and at costs lower than those of conventional methodologies. The HFB was described in Hydro focus - ing Bioreactor for Three-Dimensional Cell Culture (MSC-22358), NASA Tech Briefs, Vol. 27, No. 3 (March 2003), page 66. To recapitulate: The HFB offers a unique hydrofocusing capability that enables the creation of a low-shear liquid culture environment simultaneously with the herding of suspended cells and tissue assemblies and removal of unwanted air bubbles. The HFB includes a rotating cell-culture vessel with a centrally located sampling port and an internal rotating viscous spinner attached to a rotating base. The vessel and viscous spinner can be made to rotate at the same speed and direction or different speeds and directions to tailor the flow field and the associated hydrodynamic forces in the vessel in order to obtain low-shear suspension of cells and control of the locations of cells and air bubbles. For research and pharmaceutical-production applications, the HFB offers two major benefits: low shear stress, which promotes the assembly of cells into tissue-like three-dimensional constructs; and randomization of gravitational vectors relative to cells, which affects production of medicinal compounds. Presumably, apposition of plant cells in the absence of shear forces promotes cell-cell contacts, cell aggregation, and cell differentiation. Only gentle mixing is necessary for distributing nutrients and oxygen. It has been postulated that inasmuch as cells in the simulated microgravitation of an HFB do not need to maintain the same surface forces as in normal Earth gravitation, they can divert more energy sources to growth and differentiation and, perhaps, to biosynthesis of greater quantities of desired medicinal compounds. Because one can adjust the HFB to vary effective gravitation, one can also test the effects of intermediate levels of gravitation on biosynthesis of various products. The potential utility of this methodology for producing drugs was demonstrated in experiments in which sandalwood and Madagascar periwinkle cells were grown in an HFB. The conditions in the HFB were chosen to induce the cells to form into aggregate cultures that produced anti-cancer indole alkaloids in amounts greater than do comparable numbers of cells of the same species cultured according to previously known methodologies. The observations made in these experiments were interpreted as suggesting that the aggregation of the cells might be responsible for the enhancement of production of alkaloids

Experimental Study of Selective Laser Sintering of Parmax

Selective Laser Sintering (SLS) has been used to successfully process crystalline polymers, ceramics and metals. However, wide range of materials available and their applications have acted as an impetus to expand the applications of SLS to different material systems. This paper presents one such experimental study undertaken to explore the application of SLS to process Parmax® polymers – a family of high performance amorphous poly pphenylenes. As a part of the collaborative study, various process parameters and material formulations were tried out to ascertain the feasibility of the process and the initial results obtained look promising. This paper lists the material formulations tested and process parameters controlled. Also, analysis of the results of the experimental study and the outline of the next phase of research to be undertaken have been described. This study was motivated by the numerous applications of Parmax® in the electronics, defense and aerospace industries as well as the goal to expand the applications and utility of SLS.Mechanical Engineerin

Fractional difference inequalities of Gronwall-Bellman type

Discrete inequalities, in particular the discrete analogues of the Gronwall–Bellman inequality, have been extensively used in the analysis of nite difference equations. The aim of the present paper is to establish some fractional difference inequalities of Gronwall–Bellman type which provide explicit bounds for the solutions of fractional difference equations

Effect of silymarin on N-nitrosodiethylamine induced hepatocarcinogenesis in rats

Aim: To study the effect of silymarin on the levels of tumor markers and MDA (malondialdehyde) – DNA adduct formation during N-nitrosodiethylamine induced hepatocellular carcinoma in male Wistar albino rats. Methods: The levels of AFP, CEA and activities of liver marker enzymes in serum, MDA-DNA immunohistochemistry were done according to standard procedures in the control and experimental groups of rats. Results: Hepatocellular carcinoma was evidenced from significant (p < 0.05) increases of alpha-fetoprotein, carcinoembryonic antigen, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, acid phosphatase, lactate dehydrogenase, gamma-glutamyltransferase and 5?-nucleotidase in serum and increased MDA-DNA adducts were also observed in the tissue sections of hepatocellular carcinoma. Silymarin treatment significantly attenuated the alteration of these markers and decreased the levels of MDA-DNA adduct formation. Conclusion: Silymarin could be developed as a promising chemotherapeutic adjuvant for the treatment of liver cancer.Цель: изучить влияние силимарина на уровень экспрессии опухолевых и биохимических маркеров и формирование аддуктов малонового диальдегида с ДНК (MDA-DNA) при развитии гепатокариномы у крыс линии истар. Методы: стандартными биохимическими методами определяли активность ферментов в сыворотке крови и проводили иммуногистохимическое определение MDA-DNA в ткани печени крыс. Результаты: показано, что при развитии злокачественной гепатокарциномы в сыворотке крови животных значительно увеличивается количество альфа-фетопротеина, раковоэмбрионального антигена, активность аспартат- и аланинаминотрансферазы, щелочной и кислой фосфатазы, лактатдегидрогеназы, гаммаглутамилтрансферазы и 5-нуклеотидазы. При проведении иммуногистохимического исследования отмечали повышенное образование аддуктов MDA-DNA в ткани печени крыс со злокачественной гепатокариномой. При введении силимарина значительно снижался уровень указанных ферментов в сыворотке крови и формирование аддуктов MDA-DNA в ткани печени. Заключение: применение силимарина может быть эффективно для предупреждения развития злокачественной гепатокарциномы, индуцированной N-нитрозодиэтиламином у крыс, и этот препарат может быть многообещающим химиотерапевтическим адъювантом для лечения рака печени

Improving the Caenorhabditis elegans Genome Annotation Using Machine Learning

For modern biology, precise genome annotations are of prime importance, as they allow the accurate definition of genic regions. We employ state-of-the-art machine learning methods to assay and improve the accuracy of the genome annotation of the nematode Caenorhabditis elegans. The proposed machine learning system is trained to recognize exons and introns on the unspliced mRNA, utilizing recent advances in support vector machines and label sequence learning. In 87% (coding and untranslated regions) and 95% (coding regions only) of all genes tested in several out-of-sample evaluations, our method correctly identified all exons and introns. Notably, only 37% and 50%, respectively, of the presently unconfirmed genes in the C. elegans genome annotation agree with our predictions, thus we hypothesize that a sizable fraction of those genes are not correctly annotated. A retrospective evaluation of the Wormbase WS120 annotation [1] of C. elegans reveals that splice form predictions on unconfirmed genes in WS120 are inaccurate in about 18% of the considered cases, while our predictions deviate from the truth only in 10%–13%. We experimentally analyzed 20 controversial genes on which our system and the annotation disagree, confirming the superiority of our predictions. While our method correctly predicted 75% of those cases, the standard annotation was never completely correct. The accuracy of our system is further corroborated by a comparison with two other recently proposed systems that can be used for splice form prediction: SNAP and ExonHunter. We conclude that the genome annotation of C. elegans and other organisms can be greatly enhanced using modern machine learning technology