5,497 research outputs found

    Preparation and characterization of 5-fu loaded microspheres of eudragit and ethylcellulose

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    En la presente investigación, se han preparado microesferas de Eudragit (RS 100, RL 100 y RSPO) y etilcelulosa cargadas con 5-fluorouracilo. Se ha utilizado la técnica de “evaporación del disolvente o/o” para preparar las microesferas utilizando el sistema de (metanol + acetona)/ parafina líquida. Se ha utilizado estearato de magnesio como estabilizador de gotículas y se ha añadido n-hexano para endurecer las microesferas. Las microesferas preparadas se caracterizan por sus propiedades micromeríticas y su eficaz compresión, así como a través de la espectroscopia infrarroja transformada de Fourier (FTIR, por sus siglas en inglés) y la cromatografía en capa fina. Se han tomado microfotografías para estudiar la forma de las microesferas. La mejor cinética de liberación se ha alcanzado con el modelo de Higuchi. El tamaño de la partícula principal, la eficacia de compresión y los rendimientos de producción han sido fuertemente influenciados por el tipo de polímero y su concentración. Tras la presente investigación, se ha determinado que el Eudragit y la Etilcelulosa tienen carreras muy prometedoras en la liberación controlada para el 5-FUIn the present investigation, 5-fluorouracil loaded microspheres of Eudragit (RS 100, RL 100 and RSPO) and ethylcellulose were prepared. “O/O solvent evaporation” technique was used for preparation of microspheres using (methanol + acetone)/liquid paraffin system. Magnesium stearate was used as the droplet stabilizer and n-hexane was added to harden the microspheres. The prepared microspheres were characterized for their micromeretic properties and entrapment efficiency; as well by Fourier transform infrared spectroscopy (FTIR) and thin layer chromatography (TLC). Photomicrographs were taken to study the shape of microspheres. The best fit release kinetics was achieved with Higuchi plot. Mean particle size, entrapment efficiency and production yields were highly influenced by the type of polymer and polymer concentration. It is concluded from the present investigation that various Eudragit and Ethylcellulose are promising controlled release carriers for 5-FU

    Can the quality of social research on ethnicity be improved through the introduction of guidance? Findings from a research commissioning pilot exercise

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    As the volume of UK social research addressing ethnicity grows, so too do concerns regarding the ethical and scientific rigour of this research domain and its potential to do more harm than good. The establishment of standards and principles and the introduction of guidance documents at critical points within the research cycle might be one way to enhance the quality of such research. This article reports the findings from the piloting of a guidance document within the research commissioning process of a major funder of UK social research. The guidance document was positively received by researchers, the majority of whom reported it to be comprehensible, relevant and potentially useful in improving the quality of research proposals. However, a review of the submitted proposals suggested the guidance had had little impact on practice. While guidance may have a role to play, it will need to be strongly promoted by commissioners and other gatekeepers. Findings also suggest the possibility that guidance may discourage some researchers from engaging with ethnicity if it raises problems without solutions; highlighting the need for complementary investments in research capacity development in this area

    Radial Velocity Survey for Planets around Young stars (RVSPY) A transiting warm super-Jovian planet around HD 114082, a young star with a debris disk

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    Aiming to detect planetary companions to young stars with debris disks via the radial velocity method, we observed HD114082 during April 2018 - August 2022 as one of the targets of our RVSPY program (Radial Velocity Survey for Planets around Young stars). We used the FEROS spectrograph, mounted to the MPG/ESO 2.2 m telescope in Chile, to obtain high signal-to-noise spectra and time series of precise radial velocities (RVs). Additionally, we analyzed archival HARPS spectra and TESS photometric data. We used the CERES, CERES++ and SERVAL pipelines to derive RVs and activity indicators and ExoStriker for the independent and combined analysis of the RVs and TESS photometry. We report the discovery of a warm super-Jovian companion around HD114082 based on a 109.8±\pm0.4 day signal in the combined RV data from FEROS and HARPS, and on one transit event in the TESS photometry. The best-fit model indicates a 8.0±\pm1.0 Mjup companion with a radius of 1.00±\pm0.03 Rjup in an orbit with a semi-major axis of 0.51±\pm0.01 au and an eccentricity of 0.4±\pm0.04. The companions orbit is in agreement with the known near edge-on debris disk located at about 28 au. HD114082b is possibly the youngest (15±\pm6 Myr), and one of only three younger than 100 Myr giant planetary companions for which both their mass and radius have been determined observationally. It is probably the first properly model-constraining giant planet that allows distinguishing between hot and cold-start models. It is significantly more compatible with the cold-start model.Comment: 10 pages, 9 figures, 5 tables; Accepted for publication in A&A Letter

    Monocyte dysfunction in decompensated cirrhosis is mediated by the prostaglandin E2-EP4 pathway

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    Background & Aims: Infection is a major problem in advanced liver disease secondary to monocyte dysfunction. Elevated prostaglandin (PG)E2 is a mediator of monocyte dysfunction in cirrhosis; thus, we examined PGE2 signalling in outpatients with ascites and in patients hospitalised with acute decompensation to identify potential therapeutic targets aimed at improving monocyte dysfunction. Methods: Using samples from 11 outpatients with ascites and 28 patients hospitalised with decompensated cirrhosis, we assayed plasma levels of PGE2 and lipopolysaccharide (LPS); performed quantitative real-time PCR on monocytes; and examined peripheral blood monocyte function. We performed western blotting and immunohistochemistry for PG biosynthetic machinery expression in liver tissue. Finally, we investigated the effect of PGE2 antagonists in whole blood using polychromatic flow cytometry and cytokine production. Results: We show that hepatic production of PGE2 via the cyclo-oxygenase 1–microsomal PGE synthase 1 pathway, and circulating monocytes contributes to increased plasma PGE2 in decompensated cirrhosis. Transjugular intrahepatic sampling did not reveal whether hepatic or monocytic production was larger. Blood monocyte numbers increased, whereas individual monocyte function decreased as patients progressed from outpatients with ascites to patients hospitalised with acute decompensation, as assessed by Human Leukocyte Antigen (HLA)–DR isotype expression and tumour necrosis factor alpha and IL6 production. PGE2 mediated this dysfunction via its EP4 receptor. Conclusions: PGE2 mediates monocyte dysfunction in decompensated cirrhosis via its EP4 receptor and dysfunction was worse in hospitalised patients compared with outpatients with ascites. Our study identifies a potential drug target and therapeutic opportunity in these outpatients with ascites to reverse this process to prevent infection and hospital admission. Lay summary: Patients with decompensated cirrhosis (jaundice, fluid build-up, confusion, and vomiting blood) have high infection rates that lead to high mortality rates. A white blood cell subset, monocytes, function poorly in these patients, which is a key factor underlying their sensitivity to infection. We show that monocyte dysfunction in decompensated cirrhosis is mediated by a lipid hormone in the blood, prostaglandin E2, which is present at elevated levels, via its EP4 pathway. This dysfunction worsens when patients are hospitalised with complications of cirrhosis compared with those in the outpatients setting, which supports the EP4 pathway as a potential therapeutic target for patients to prevent infection and hospitalisation

    Risk factors for high anti-HHV-8 antibody titers (≥1:51,200) in black, HIV-1 negative South African cancer patients: a case control study

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    Background: Infection with human herpesvirus 8 (HHV-8) is the necessary causal agent in the development of Kaposi's sarcoma (KS). Infection with HIV-1, male gender and older age all increase risk for KS. However, the geographic distribution of HHV-8 and KS both prior to the HIV/AIDS epidemic and with HIV/AIDS suggest the presence of an additional co-factor in the development of KS. Methods: Between January 1994 and October 1997, we interviewed 2576 black in-patients with cancer in Johannesburg and Soweto, South Africa. Blood was tested for antibodies against HIV-1 and HHV-8 and the study was restricted to 2191 HIV-1 negative patients. Antibodies against the latent nuclear antigen of HHV-8 encoded by orf73 were detected with an indirect immunofluorescence assay. We examined the relationship between high anti-HHV-8 antibody titers (≥1:51,200) and sociodemographic and behavioral factors using unconditional logistic regression models. Variables that were significant at p = 0.10 were included in multivariate analysis. Results: Of the 2191 HIV-1 negative patients who did not have Kaposi's sarcoma, 854 (39.0%) were positive for antibodies against HHV-8 according to the immunofluorescent assay. Among those seropositive for HHV-8, 530 (62.1%) had low titers (1:200), 227 (26.6%) had medium titers (1:51,200) and 97 (11.4%) had highest titers (1:204,800). Among the 2191 HIV-1 negative patients, the prevalence of high anti-HHV-8 antibody titers (≥1:51,200) was independently associated with increasing age (ptrend = 0.04), having a marital status of separated or divorced (p = 0.003), using wood, coal or charcoal as fuel for cooking 20 years ago instead of electricity (p = 0.02) and consuming traditional maize beer more than one time a week (p = 0.02; p-trend for increasing consumption = 0.05) although this may be due to chance given the large number of predictors considered in this analysis. Conclusions: Among HIV-negative subjects, patients with high anti-HHV-8 antibody titers are characterized by older age. Other associations that may be factors in the development of high anti- HHV-8 titers include exposure to poverty or a low socioeconomic status environment and consumption of traditional maize beer. The relationship between these variables and high anti- HHV-8 titers requires further, prospective study

    Three dimensional porous scaffolds derived from collagen, elastin and fibrin proteins orchestrate adipose tissue regeneration

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    Current gold standard to treat soft tissue injuries caused by trauma and pathological condition are autografts and off the shelf fillers, but they have inherent weaknesses like donor site morbidity, immuno-compatibility and graft failure. To overcome these limitations, tissue-engineered polymers are seeded with stem cells to improve the potential to restore tissue function. However, their interaction with native tissue is poorly understood so far. To study these interactions and improve outcomes, we have fabricated scaffolds from natural polymers (collagen, fibrin and elastin) by custom-designed processes and their material properties such as surface morphology, swelling, wettability and chemical cross-linking ability were characterised. By using 3D scaffolds, we comprehensive assessed survival, proliferation and phenotype of adipose-derived stem cells in vitro. In vivo, scaffolds were seeded with adipose-derived stem cells and implanted in a rodent model, with X-ray microtomography, histology and immunohistochemistry as read-outs. Collagen-based materials showed higher cell adhesion and proliferation in vitro as well as higher adipogenic properties in vivo. In contrast, fibrin demonstrated poor cellular and adipogenesis properties but higher angiogenesis. Elastin formed the most porous scaffold, with cells displaying a non-aggregated morphology in vitro while in vivo elastin was the most degraded scaffold. These findings of how polymers present in the natural polymers mimicking ECM and seeded with stem cells affect adipogenesis in vitro and in vivo can open avenues to design 3D grafts for soft tissue repair

    RVSPY -- Radial Velocity Survey for Planets around Young Stars. Target characterization and high-cadence survey

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    We introduce our Radial Velocity Survey for Planets around Young stars (RVSPY), characterise our target stars, and search for substellar companions at orbital separations smaller than a few au from the host star. We use the FEROS spectrograph to obtain high signal-to-noise spectra and time series of precise radial velocities (RVs) of 111 stars most of which are surrounded by debris discs. Our target stars have spectral types between early F and late K, a median age of 400 Myr, and a median distance of 45 pc. We determine for all target stars their basic stellar parameters and present the results of the high-cadence RV survey and activity characterization. We achieve a median single-measurement RV precision of 6 m/s and derive the short-term intrinsic RV scatter of our targets (median 22 m/s), which is mostly caused by stellar activity and decays with age from >100 m/s at 500 Myr. We discover six previously unknown close companions with orbital periods between 10 and 100 days, three of which are low-mass stars, and three are in the brown dwarf mass regime. We detect no hot companion with an orbital period <10 days down to a median mass limit of ~1 M_Jup for stars younger than 500 Myr, which is still compatible with the established occurrence rate of such companions around main-sequence stars. We find significant RV periodicities between 1.3 and 4.5 days for 14 stars, which are, however, all caused by rotational modulation due to starspots. We also analyse the TESS photometric time series data and find significant periodicities for most of the stars. For 11 stars, the photometric periods are also clearly detected in the RV data. We also derive stellar rotation periods ranging from 1 to 10 days for 91 stars, mostly from TESS data. From the intrinsic activity-related short-term RV jitter, we derive the expected mass-detection thresholds for longer-period companions.Comment: 24 pages, 14 figures, 4 tables; Accepted for publication in A&

    Phenotypic covariance of longevity, immunity and stress resistance in the Caenorhabditis nematodes

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    Background \ud Ageing, immunity and stresstolerance are inherent characteristics of all organisms. In animals, these traits are regulated, at least in part, by forkhead transcription factors in response to upstream signals from the Insulin/Insulin– like growth factor signalling (IIS) pathway. In the nematode Caenorhabditis elegans, these phenotypes are molecularly linked such that activation of the forkhead transcription factor DAF-16 both extends lifespan and simultaneously increases immunity and stress resistance. It is known that lifespan varies significantly among the Caenorhabditis species but, although DAF-16 signalling is highly conserved, it is unclear whether this phenotypic linkage occurs in other species. Here we investigate this phenotypic covariance by comparing longevity, stress resistance and immunity in four \ud Caenorhabditis species. \ud \ud Methodology/Principal Findings \ud We show using phenotypic analysis of DAF-16 influenced phenotypes that among four closely related Caenorhabditis nematodes, the gonochoristic species (Caenorhabditis remanei and Caenorhabditis brenneri) have diverged \ud significantly with a longer lifespan, improved stress resistance and higher immunity than the hermaphroditic species (C. elegans and Caenorhabditis briggsae). Interestingly, we also observe significant differences in expression levels between the daf-16 homologues in these species using Real-Time PCR, which positively correlate with the observed phenotypes. Finally, we provide additional evidence in support of a role for DAF-16 in regulating phenotypic coupling by using a combination of wildtype isolates, constitutively active daf-16 mutants and bioinformatic analysis. \ud \ud Conclusions \ud The gonochoristic species display a significantly longer lifespan (p < 0.0001)and more robust immune and stress response (p<0.0001, thermal stress; p<0.01, heavy metal stress; p<0.0001, pathogenic stress) than the hermaphroditic species. Our data suggests that divergence in DAF-16 mediated phenotypes may underlie many of the differences observed between these four species of Caenorhabditis nematodes. These findings are further supported by the correlative higher daf-16 expression levels among the gonochoristic species and significantly higher lifespan, immunity and stress tolerance in the constitutively active daf-16 hermaphroditic mutants

    Imaging-guided chest biopsies: techniques and clinical results

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    Background This article aims to comprehensively describe indications, contraindications, technical aspects, diagnostic accuracy and complications of percutaneous lung biopsy. Methods Imaging-guided biopsy currently represents one of the predominant methods for obtaining tissue specimens in patients with lung nodules; in many cases treatment protocols are based on histological information; thus, biopsy is frequently performed, when technically feasible, or in case other techniques (such as bronchoscopy with lavage) are inconclusive. Results Although a coaxial system is suitable in any case, two categories of needles can be used: fine-needle aspiration biopsy (FNAB) and core-needle biopsy (CNB), with the latter demonstrated to have a slightly higher overall sensitivity, specificity and accuracy. Conclusion Percutaneous lung biopsy is a safe procedure even though a few complications are possible: pneumothorax, pulmonary haemorrhage and haemoptysis are common complications, while air embolism and seeding are rare, but potentially fatal complications
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