Cosmic voids::a novel probe to shed light on our Universe

Cosmic voids, the less dense patches of the Universe, are promising laboratories to extract cosmological information. Thanks to their unique low density character, voids are extremely sensitive to diffuse components such as neutrinos and dark energy, and represent ideal environments to study modifications of gravity, where the effects of such modifications are expected to be more prominent. Robust void-related observables, including for example redshift-space distortions (RSD) and weak lensing around voids, are a promising way to chase and test new physics. Cosmological analysis of the large-scale structure of the Universe predominantly relies on the high density regions. Current and upcoming surveys are designed to optimize the extraction of cosmological information from these zones, but leave voids under-exploited. A dense, large area spectroscopic survey with imaging capabilities is ideal to exploit the power of voids fully. Besides helping illuminate the nature of dark energy, modified gravity, and neutrinos, this survey will give access to a detailed map of under-dense regions, providing an unprecedented opportunity to observe and study a so far under-explored galaxy population

Valutazione dell'impatto della mucoadesività di nanoparticelle polimeriche sulla biodisponibilità orale di un farmaco proteico modello

Scopo tesi: Confronto tra nanoparticelle polimeriche mucoadesive contenenti il farmaco proteico modello Fluoresceina isotiocianato destrano (FD4) con lo scopo di valutare l’influenza della mucoadesività sulla biodisponibilità orale di FD4. Metodi: Sono stati utilizzati come polimeri i derivati del chitosano a basso peso molecolare caratterizzati da piccole catene laterali contenenti gruppi ammonici quaternari adiacenti (QA-Ch). In seguito, su questi derivati, sono stati introdotti gruppi tiolici (QA-Ch-SH) mediante la formazione di legami ammidici con acido tioglicolico. A partire dai derivati QA-Ch-SH sono stati sintetizzati i derivati chitosano S-protetti (QA-Ch-S-protetti) mediante l’addizione ai gruppi tiolici liberi del ligando aromatico 6-mercaptonicotinammide. Con i derivati QA-Ch e QA-Ch-S-protetti sono state preparate nanoparticelle (Np) contenenti FD4 mediante reticolazione ionotropica con acido ialuronico depolimerizzato. Dopo preparazione, le Np sono state purificate mediante centrifugazione, allontanamento del surnatante, ridispersione del pellet e liofilizzazione e sono state caratterizzate per dimensioni, indice di polidispersione (PI), efficienza di incapsulamento (EI) e potenziale zeta (ZP). Il rilascio di FD4 dalle Np è stato studiato sottoponendo a dialisi le dispersioni, interrompendo le dialisi dopo 1, 3, 5, 15 e 24h e determinando a ciascuno di tali tempi la % di FD4 passata nella fase ricevente (FFR), quella presente nella fase donatrice ma esterna alle Np (FFD) e quella ancora associata alle Np (FNP). Le Np sono state sottoposte a dialisi anche al fine di determinare il binding tra FD4 e la superficie delle Np. La permeazione di FD4 in vitro è stata studiata utilizzando celle di tipo Ussing e le proprietà mucoadesive delle Np sono state studiate ex-vivo utilizzando intestino isolato di ratto. Inoltre, utilizzando un esperimento messo a punto nel nostro laboratorio, è stata valutata la capacità delle Np di permeare attraverso il muco isolato dall’intestino del maiale. Infine sono stati effettuati in vivo su ratti studi di biodisponibilità orale. Risultati: Le dimensioni medie delle Np e i valori di PI (370-390 nm, 0.3-0.4 range) non sono significativamente diversi tra i due tipi di Np. I valori di ZP (13.4, 11.9) sono positivi grazie alla presenza di ioni ammonio quaternari sulla loro superficie. L’EI è circa il 20 % e dopo 5h di dialisi l’80 % circa della quantità incapsulata rimane intrappolata nelle Np. Dallo studio di permeazione è emerso che il fattore di promozione della permeazione è circa 2 in entrambi i tipi di Np. Lo studio in vitro del trasporto acqua-assistito attraverso il muco ha dimostrato che entrambi i tipi di Np sono in grado di attraversare il muco e il trasporto è più lento nel caso delle Np preparate a partire da QA-Ch-S-protetto (Np QA-Ch-S-protetto) che dagli studi di mucoadesione ex-vivo erano risultate più mucoadesive di quelle preparate a partire da QA-Ch (Np QA-Ch). Gli studi in vivo hanno dimostrato che entrambi i due tipi di Np riescono ad aumentare significativamente la biodisponibilità orale di FD4. In particolare la biodisponibilità di FD4 è risultata significativamente più altra nel caso di Np a base di QA-Ch-S-protetto, indicando che Np più mucoadesive, sebbene vengano rallentate maggiormente nel trasporto attraverso il muco intestinale, risultano più efficaci nell’aumentare la biodisponibilità di farmaci in esse incapsulati rispetto a Np meno mucoadesive. Conclusioni: Nanoparticelle preparate a partire da QA-Ch e QA-Ch-S-protetto e caricate con FD4 riescono a oltrepassare la barriera mucosale grazie al flusso intestinale di acqua e la loro mucoadesività prolunga il tempo di contatto con il sito di assorbimento favorendo un aumento della biodisponibiltà orale

Placental Tumor Necrosis Factor Alpha but Not Gamma Interferon Is Associated with Placental Malaria and Low Birth Weight in Malawian Women

Malaria in pregnancy predisposes to maternal anemia and low birth weight (LBW). We examined the possible roles of the cytokines tumor necrosis factor alpha (TNF-α) and gamma interferon (IFN-γ) in these adverse outcomes. We measured cytokine concentrations in placental, peripheral, and cord blood plasma in relation to malaria parasitemia and placental monocyte accumulation in 276 Malawian women. Maternal hemoglobin concentration, human immunodeficiency virus status, and infant birth weight were determined. Concentrations of TNF-α in placental blood were correlated with densities of Plasmodium falciparum-infected erythrocytes (P < 0.0001) and of intervillous monocyte infiltrates (P < 0.0001) on placental histology. Peripheral blood TNF-α concentrations were relatively low and were weakly associated with malaria. TNF-α concentrations were higher in placental blood, where they were strongly associated with malaria. Placental plasma TNF-α levels were higher in women who had LBW babies (P = 0.0027), women with febrile symptoms (P < 0.0001), and teenage mothers (P = 0.04) than in other women. The presence of TNF-α in cord blood was not associated with malaria infection. IFN-γ levels were infrequently elevated, and elevated IFN-γ levels were not associated with poor pregnancy outcomes. Placental production of TNF-α, but not of IFN-γ, may be implicated in impaired fetal growth in Malawian women

Use of zebrafish embryos as avatar of patients with pancreatic cancer: A new xenotransplantation model towards personalized medicine

BACKGROUND The response to chemotherapy treatment of patients with pancreatic ductal adenocarcinoma (PDAC) is difficult to predict and the identification of patients who most likely will benefit from aggressive chemotherapy approaches is crucial. The concept of personalized medicine has emerged in the last years with the objective to tailor the medical treatment to the individual characteristics of each patient, and particularly to the tumor biology of each patient. The need for in-vivo xenotransplantation models for cancer patients has increased exponentially, and for this reason zebrafish avatars have gained popularity. Preliminary studies were conducted also with PDAC tissue. AIM To develop a simple, not expensive, diffusible zebrafish embryo model as avatar for patients affected by PDAC. METHODS Tumor tissue was taken from the surgical specimen by the histopathologist. After its fragmentation into small pieces, they are stained with CM-Dil. Small pieces of stained tissue were transplanted into the yolk of wt AB zebrafish embryos with a glass capillary needle. Embryos were incubated at 35 °C in E3 medium supplemented with 1% Pen/Strep in the presence or absence of drugs for the following days in respect of the treatment plan (Gemcitabine; Gemcitabine and Oxaliplatin; Gemcitabine and nab-Paclitaxel; 5-Fluorouracil and Folinic acid and Oxaliplatin and Irinotecan). The response of zebrafish xenografts to the chemotherapy options has been analyzed by monitoring the fluorescent stained area at 2 h post injection (hpi), 1 d and 2 d post injection (dpi). In each time point, the mean size of the stained area was measured by ImageJ and it was normalized with respect to the 1 dpi time point mean relative tumor area (RTA). We evaluated the effect of the chemotherapy exposition comparing the mean RTA of each treated subgroup and the control group and evaluating the percentage reduction of the mean RTA by comparing each treated subgroup with the control group. RESULTS Between July 2018 and October 2019, a total of 15 patients with pancreatic cancer were prospectively enrolled. In all cases, it was possible to take a fragment of the tumor from the surgical specimen for the xenotransplantation in the zebrafish embryos. The histological examination confirmed the presence of a PDAC in all cases. In absence of chemotherapy (control group), over time the Dil-stained area showed a statistically significant increase in all cases. A statistically significant reduction of the mean RTA in the treated subgroups for at least one chemotherapy scheme was reported in 6/15 (40%) cases. The analysis of the percentage reduction of the RTA in treated subgroups in comparison to the control group revealed the presence of a linear relationship in each subgroup between the percentage reduction of the RTA and the number of cases reporting each percentage threshold considered for the analysis. CONCLUSION Our model seems to be effective for the xenotransplantation of PDAC tissue and evaluation of the effect of each chemotherapy scheme on the xenotransplanted tumor tissue

H3K4me3 Breadth Is Linked to Cell Identity and Transcriptional Consistency.

Trimethylation of histone H3 at lysine 4 (H3K4me3) is a chromatin modification known to mark the transcription start sites of active genes. Here, we show that H3K4me3 domains that spread more broadly over genes in a given cell type preferentially mark genes that are essential for the identity and function of that cell type. Using the broadest H3K4me3 domains as a discovery tool in neural progenitor cells, we identify novel regulators of these cells. Machine learning models reveal that the broadest H3K4me3 domains represent a distinct entity, characterized by increased marks of elongation. The broadest H3K4me3 domains also have more paused polymerase at their promoters, suggesting a unique transcriptional output. Indeed, genes marked by the broadest H3K4me3 domains exhibit enhanced transcriptional consistency rather than increased transcriptional levels, and perturbation of H3K4me3 breadth leads to changes in transcriptional consistency. Thus, H3K4me3 breadth contains information that could ensure transcriptional precision at key cell identity/function genes. Cell 2014 Jul 31; 158(3):673-88