Determination of the dry mass of nervous and glial cell nuclei by interference microscopy

Riassunto In questo lavoro si descrive una nuova metodica per la determinazione della massa secca dei nuclei delle cellule nervose o gliali mediante il microscopio ad interferenza. Sono riferiti i valori della massa secca, dei volumi e della concentrazione dei nuclei isolati sia da tessuto liofilizzato che da tessuto fresco.

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This investigation was supported by a grant to this Department from the Consiglio Nazionale delle Ricerche (No. 04/76/4/3482).     

The reaction of arylthionylhydrazines with sodium

Riassunto Trattando le tionil-idrazine opportunamente sostituite, con sodio polvere in toluolo anidro, si ottengono i corrispondenti tiofenoli. Tale reazione è inibita da sostituenti fortemente elettron-attrattori.     

Cavity solitons as pixels in semiconductor microcavities

Cavity solitons are localized intensity peaks that can form in a homogeneous background of radiation. They are generated by shining laser pulses into optical cavities that contain a nonlinear medium driven by a coherent field (holding beam). The ability to switch cavity solitons on and off and to control their location and motion by applying laser pulses makes them interesting as potential 'pixels' for reconfigurable arrays or all-optical processing units. Theoretical work on cavity solitons has stimulated a variety of experiments in macroscopic cavities and in systems with optical feedback. But for practical devices, it is desirable to generate cavity solitons in semiconductor structures, which would allow fast response and miniaturization. The existence of cavity solitons in semiconductor microcavities has been predicted theoretically, and precursors of cavity solitons have been observed, but clear experimental realization has been hindered by boundary-dependence of the resulting optical patterns-cavity solitons should be self-confined. Here we demonstrate the generation of cavity solitons in vertical cavity semiconductor microresonators that are electrically pumped above transparency but slightly below lasing threshold. We show that the generated optical spots can be written, erased and manipulated as objects independent of each other and of the boundary. Numerical simulations allow for a clearer interpretation of experimental results.     

Thromboplastic and fibrinolytic activity in valves of the pig heart

Zusammenfassung Herzklappen vom Schwein wurden auf ihre thromboplastische und fibrinolytische Aktivität untersucht. Die Konzentration von Gewebsthromboplastin war in allen Herzklappen (Segel- und Taschenklappen) gering und stimmt mit der in menschlichen Herzklappen gemessenen überein. Im Gegensatz dazu weisen Schweineherzklappen eine höhere fibrinolytische Aktivität als menschliche Herzklappen auf, wahrscheinlich als Folge der reicheren Vaskularisierung.     

(Z)-9-tetradecen-1-ol and (Z)-9-tetradecenyl acetate: A potent attractant system for maleSesamia cretica Led. (Lep., Noctuidae)

Summary Field studies have shown that a combination of (Z)-9-tetradecenol with (Z)-9-tetradecenyl acetate is an effective attractant for maleSesamia cretica Led., a pest of sorghum crops. These studies also indicated that the most effective composition is 7525 (alcohol:acetate).We thank Dr E. Berio for the insect determination.     

Resetting epigenetic signatures to induce somatic cell reprogramming

Somatic cell reprogramming consists of the induction of a complex sequence of events that results in the modification of the developmental state of the cell. It is now routinely possible to reprogram fully differentiated cells back to pluripotent cells, and to transdifferentiate cells of a given type in cells of a totally different lineage origin. However, whether there are key initiating factors that are distinct from those that control stem-cell renewal and that can initiate the reprogramming process remains unknown. In contrast, what is clear is that, by modifying the epigenetic status of a cell, its reprogramming can be initiated. Here, we review the current literature that shows how the plasticity of a cell can be modulated by modifying its epigenetic status, and we discuss how epigenetic barriers can be removed, to induce an efficient reprogramming process.     

Frequent mutation of histone-modifying genes in non-Hodgkin lymphoma

Follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL) are the two most common non-Hodgkin lymphomas (NHLs). Here we sequenced tumour and matched normal DNA from 13 DLBCL cases and one FL case to identify genes with mutations in B-cell NHL. We analysed RNA-seq data from these and another 113 NHLs to identify genes with candidate mutations, and then re-sequenced tumour and matched normal DNA from these cases to confirm 109 genes with multiple somatic mutations. Genes with roles in histone modification were frequent targets of somatic mutation. For example, 32% of DLBCL and 89% of FL cases had somatic mutations in MLL2, which encodes a histone methyltransferase, and 11.4% and 13.4% of DLBCL and FL cases, respectively, had mutations in MEF2B, a calcium-regulated gene that cooperates with CREBBP and EP300 in acetylating histones. Our analysis suggests a previously unappreciated disruption of chromatin biology in lymphomagenesis.     

Nonsense-mediated decay microarray analysis identifies mutations of EPHB2 in human prostate cancer

The identification of tumor-suppressor genes in solid tumors by classical cancer genetics methods is difficult and slow. We combined nonsense-mediated RNA decay microarrays and array-based comparative genomic hybridization for the genome-wide identification of genes with biallelic inactivation involving nonsense mutations and loss of the wild-type allele. This approach enabled us to identify previously unknown mutations in the receptor tyrosine kinase gene EPHB2. The DU 145 prostate cancer cell line, originating from a brain metastasis, carries a truncating mutation of EPHB2 and a deletion of the remaining allele. Additional frameshift, splice site, missense and nonsense mutations are present in clinical prostate cancer samples. Transfection of DU 145 cells, which lack functional EphB2, with wild-type EPHB2 suppresses clonogenic growth. Taken together with studies indicating that EphB2 may have an essential role in cell migration and maintenance of normal tissue architecture, our findings suggest that mutational inactivation of EPHB2 may be important in the progression and metastasis of prostate cancer.