618 research outputs found
Catalytic Activity of Myoglobin Immobilized on Zirconium Phosphonates.
The adsorption and catalytic activity of myoglobin (Mb) on zirconium phosphonates (R-zirconium
benzenephosphonate (R-ZrBP), R-zirconium carboxyethanephosphonate (R-ZrCEP), and a novel layered
zirconium fluoride aminooctyl-N,N-bis(methylphosphonate) (ZrC8)) were investigated. The maximum
adsorption was reached after 16 h of contact and was greater on hydrophobic supports such as R-ZrBP
and ZrC8 compared to hydrophilic supports such as R-ZrCEP. The equilibrium adsorption isotherms fitted
the Langmuir equation, suggesting the presence of a monolayer of protein molecules on the support surfaces.
The catalytic activities of free Mb and of the obtained biocomposites were studied in terms of the oxidation
of two aromatic substrates, o-phenylenediamine and 2-methoxyphenol (guaiacol), by hydrogen peroxide.
The oxidation catalyzed by immobilized myoglobin followed the Michaelis-Menten kinetics, similar to
oxidation by free Mb. The kinetic parameters, kcat and KM, were significantly affected by the adsorption
process. Mb/R-ZrCEP was the most efficient biocatalyst obtained, probably because of the hydrophilic
nature of the support. The effect of immobilization on the stability of Mb toward inactivation by hydrogen
peroxide was also investigated, and an increased resistance was found. The biocomposites obtained can
be stored at 4 °C for months without a significant loss of catalytic activity
Angiogenic gene expression and vascular density are reflected in ultrasonographic features of synovitis in early Rheumatoid Arthritis: an observational study.
INTRODUCTION: Neovascularization contributes to the development of sustained synovial inflammation in the early stages of Rheumatoid Arthritis. Ultrasound (US) provides an indirect method of assessing synovial blood flow and has been shown to correlate with clinical disease activity in patients with Rheumatoid Arthritis. This study examines the relationship of US determined synovitis with synovial vascularity, angiogenic/lymphangiogenic factors and cellular mediators of inflammation in a cohort of patients with early Rheumatoid Arthritis (RA) patients prior to therapeutic intervention with disease modifying therapy or corticosteroids. METHODS: An ultrasound guided synovial biopsy of the supra-patella pouch was performed in 12 patients with early RA prior to treatment. Clinical, US and biochemical assessments were undertaken prior to the procedure. Ultrasound images and histological samples were obtained from the supra-patella pouch. Histological samples were stained for Factor VIII and a-SMA (a-smooth muscle actin). Using digital imaging analysis a vascular area score was recorded. QT-PCR (quantitative-PCR) of samples provided quantification of angiogenic and lymphangiogenic gene expression and immunohistochemistry stained tissue was scored for macrophage, T cell and B cell infiltration using an existing semi-quantitative score. RESULTS: Power Doppler showed a good correlation with histological vascular area (Spearman r--0.73) and angiogenic factors such as vascular endothelial growth factor-A (VEGF-A), Angiopoietin 2 and Tie-2. In addition, lymphangiogenic factors such as VEGF-C and VEGF-R3 correlated well with US assessment of synovitis. A significant correlation was also found between power Doppler and synovial thickness, pro-inflammatory cytokines and sub-lining macrophage infiltrate. Within the supra-patella pouch there was no significant difference in US findings, gene expression or inflammatory cell infiltrate between any regions of synovium biopsied. CONCLUSION: Ultrasound assessment of synovial tissue faithfully reflects synovial vascularity. Both grey scale and power Doppler synovitis in early RA patients correlate with a pro-angiogenic and lymphangiogenic gene expression profile. In early RA both grey scale and power Doppler synovitis are associated with a pro-inflammatory cellular and cytokine profile providing considerable validity in its use as an objective assessment of synovial inflammation in clinical practice
Increased serum OPG in atrophic nonunion shaft fractures
Background Bone repair alteration is hypothesized for nonunion fracture pathogenesis. Since it is involved in osteoclast regulation, the RANK/RANKL/OPG system (receptor activator of nuclear factor kB/its ligand/osteoprotegerin) may play a role.
Materials and methods Serum OPG, free RANKL, bone alkaline phosphatase (BAP), osteocalcin (OC), and urinary deoxypyridinoline (DPD) were determined in 16 male patients (20\u201339 years) with long bone atrophic nonunion fractures. Serum markers were also measured in 18 agematched male controls who healed from the same type of fractures within six months, and in 14 age-matched male controls who were healing from the same fractures one month after injury. One-way ANOVA and Bonferroni\u2019s test were used for statistical analysis.
Results Only OPG was significantly higher (0.56 sd 0.11 ng/ml) in the patients compared to healed (0.26 sd 0.04 ng/ml; P\0.001) and healing (0.29 sd 0.09 ng/ml; P\0.001) controls. The patients\u2019 DPD levels were normal. No correlations were found between bone markers and the characteristics of the subjects in all groups.
Conclusions A normal steady state of bone metabolism seems to be present in patients with atrophic nonunion fractures, despite the high serum OPG. The reason for the inability of the patients\u2019 OPG to inhibit osteoclastic activity is unknown. Osteoblast activity also appears normal, so another cellular source of OPG can be hypothesized
Ultrafast optical generation of coherent phonons in CdTe1-xSex quantum dots
We report on the impulsive generation of coherent optical phonons in
CdTe0.68Se0.32 nanocrystallites embedded in a glass matrix. Pump probe
experiments using femtosecond laser pulses were performed by tuning the laser
central energy to resonate with the absorption edge of the nanocrystals. We
identify two longitudinal optical phonons, one longitudinal acoustic phonon and
a fourth mode of a mixed longitudinal-transverse nature. The amplitude of the
optical phonons as a function of the laser central energy exhibits a resonance
that is well described by a model based on impulsive stimulated Raman
scattering. The phases of the coherent phonons reveal coupling between
different modes. At low power density excitations, the frequency of the optical
coherent phonons deviates from values obtained from spontaneous Raman
scattering. This behavior is ascribed to the presence of electronic impurity
states which modify the nanocrystal dielectric function and, thereby, the
frequency of the infrared-active phonons
Evaluating the contribution of the gene TARDBP in Italian patients with amyotrophic lateral sclerosis
Background and objectives: Genetic variants in the gene TARDBP, encoding TDP-43 protein, are associated with amyotrophic lateral sclerosis (ALS) in familial (fALS) and sporadic (sALS) cases. Objectives of this study were to assess the contribution of TARDBP in a large cohort of Italian ALS patients, to determine the TARDBP-associated clinical features and to look for genotype-phenotype correlation and penetrance of the mutations.Methods: A total of 1992 Italian ALS patients (193 fALS and 1799 sALS) were enrolled in this study. Sanger sequencing of TARDBP gene was performed in patients and, when available, in patients' relatives.Results: In total, 13 different rare variants were identified in 43 index cases (10 fALS and 33 sALS) with a cumulative mutational frequency of 2.2% (5.2% of fALS, 1.8% of sALS). The most prevalent variant was the p.A382T followed by the p.G294V. Cognitive impairment was detected in almost 30% of patients. While some variants, including the p.G294V and the p.G376D, were associated with restricted phenotypes, the p.A382T showed a marked clinical heterogeneity regarding age of onset, survival and association with cognitive impairment. Investigations in parents, when possible, showed that the variants were inherited from healthy carriers and never occurred de novo.Conclusions: In our cohort, TARDBP variants have a relevant frequency in Italian ALS patients and they are significantly associated with cognitive impairment. Clinical presentation is heterogeneous. Consistent genotype-phenotype correlations are limited to some mutations. A marked phenotypic variability characterizes the p.A382T variant, suggesting a multifactorial/oligogenic pathogenic mechanism
Dense transcript profiling in single cells by image correlation decoding
Sequential barcoded fluorescent in situ hybridization (seqFISH) allows large numbers of molecular species to be accurately detected in single cells, but multiplexing is limited by the density of barcoded objects. We present correlation FISH (corrFISH), a method to resolve dense temporal barcodes in sequential hybridization experiments. Using corrFISH, we quantified highly expressed ribosomal protein genes in single cultured cells and mouse thymus sections, revealing cell-type-specific gene expression
Il Modello ACASA per la stima degli scambi di carbonio negli ecosistemi mediterranei
L’attività di ricerca finalizzata allo sviluppo e alla validazione di modellistica avanzata per
la contabilizzazione del bilancio del carbonio nei sistemi agrari e forestali nasce da una intensa
collaborazione con l’Università della California. In particolare è in fase di studio il modello
ACASA (Advanced Canopy-Atmosphere-Soil Algorithm), che è attualmente uno dei modelli del
tipo soil-vegetation-atmosphere transfer (SVAT) più sofisticati. ACASA contiene equazioni
differenziali di terzo ordine per simulare i flussi di energia e materia nella canopy (10 strati
atmosferici all’interno e 10 al di sopra), mentre il suolo è suddiviso in 15 strati. Una combinazione
delle equazioni di Ball-Berry e Farquhar è utilizzata per stimare il flusso di CO2. Il modello
considera gli effetti dello stress idrico sulla traspirazione e sull’assimilazione della vegetazione
Advanced-Canopy-Atmosphere-Soil Algorithm (ACASA model) for estimating mass and energy fluxes
There is a recognized need to improve land surface models that simulate mass and energy fluxes
between terrestrial ecosystems and atmosphere. In particular, long-term land planning strategies at local
and regional scales require better understanding of agricultural ecosystem capacity to exchange CO2
and water. One of the more elaborate models for flux modelling is the Advanced Canopy-Atmosphere-Soil
Algorithm (ACASA) model (Pyles et al., 2000), which provides micro-scale and regional-scale
fluxes. The ACASA model allows for characterization of energy and carbon fluxes. It is a higher-order
closure model used to estimate fluxes and profiles of heat, water vapor, carbon and momentum within
and above canopy using third-order closure equations. It also estimates turbulent profiles of velocity,
temperature, humidity within and above canopy. The ACASA model estimates CO2 fluxes using a
combination of Ball-Berry and Farquhar equations. In addition, the effects of water stress on stomata,
transpiration and CO2 assimilation are considered. The model was mainly used over dense canopies
(Pyles et al. 2000, 2003) in the past, so the aim of this work was to test the ACASA model over a
sparse canopy for estimating mass and energy fluxes, comparing model output with field measurements
taken over a vineyard located in Montalcino, Tuscany, Italy
Intranasal administration of acetylcholinesterase inhibitors
This short review outlines the rationale, challenges, and opportunities for intranasal acetylcholinesterases, in particular galantamine. An in vitro screening model facilitated the development of a therapeutically viable formulation. In vivo testing confirmed achievement of therapeutically relevant drug levels that matched or exceeded those for oral dosing, with a dramatic reduction in undesired emetic responses. Intranasal drug delivery is an effective option for the treatment of Alzheimer's disease and other central nervous system disorders
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