Effect of orthophosphate on the transaldolase reaction.

In previous studies' with a dialyzed supernatant fraction from rat liver it was observed that the formation of heptulose phosphate from fructose g-phosphate was significantly inhibited by inorganic phosphate. It has since been shown (1, 2) that the activity of the dialyzed liver fraction can be related to its content of transketolase and transaldolase and it became of interest to determine whether the inhibition of the over-all process by phosphate was due to its effect on one or both of the enzymes involved in this process. Preliminary experiments indicated that both transketolase and transaldolase were inhibited by inorganic phosphate when the enzymes were tested in the usual assay procedures. The effect of phosphate on transaldolase is reported in the present paper

Extracellular release of the ‘differentiation enhancing factor’, a HMG1 protein type, is an early step in murine erythroleukemia cell differentiation

AbstractDifferentiation enhancing factor (DEF) is a 29 kDa protein expressed in murine erythroleukemia (MEL) cells and active in promoting a significant increase in the rate of hexamethylenebisacetamide induced differentiation of these cells. The factor was recently shown to possess an amino acid sequence identical to that reported for one of the HMG1 proteins, designated as ‘amphoterin’ on the basis of its highly dipolar sequence. In the present study, we have expressed DEF cDNA in an E. coli strain and found that the recombinant protein has functional properties identical to those observed with native DEF. Furthermore, we demonstrate that, following MEL cell stimulation with the chemical inducer, DEF is secreted in large amounts in the extracellular medium. In fact, the N-terminal sequence and the partial amino acid sequence of tryptic peptides from the secreted protein correspond to those of DEF isolated from the soluble fraction of resting MEL cells. These results are indicative for an extracellular localization as the site of action of DEF and suggest a novel function for proteins belonging to the HMG1 family. Finally, the early decay of DEF mRNA, in chemical induced MEL cells, support the hypothesis that the involvement of the enhancing factor occurs and is completed in the early phases of cell differentiation

Polyelectrolyte-coated mesoporous bioactive glasses via layer-by-layer deposition for sustained co-delivery of therapeutic ions and drugs

In the field of bone regeneration, considerable attention has been addressed towards the use of mesoporous bioactive glasses (MBGs), as multifunctional therapeutic platforms for advanced medical devices. In fact, their extremely high exposed surface area and pore volume allow to load and the release of several drugs, while their framework can be enriched with specific therapeutic ions allowing to boost the tissue regeneration. However, due to the open and easily accessible mesopore structure of MBG, the release of the incorporated therapeutic molecules shows an initial burst effect leading to unsuitable release kinetics. Hence, a still open challenge in the design of drug delivery systems based on MBGs is the control of their release behavior. In this work, Layer-by-layer (LbL) deposition of polyelectrolyte multi-layers was exploited as a powerful and versatile technique for coating the surface of Cu-substituted MBG nanoparticles with innovative multifunctional drug delivery systems for co-releasing of therapeutic copper ions (exerting pro-angiogenic and anti-bacterial effects) and an anti-inflammatory drug (ibuprofen). Two different routes were investigated: in the first strategy, chitosan and alginate were assembled by forming the multi-layered surface, and, successively, ibuprofen was loaded by incipient wetness impregnation, while in the second approach, alginate was replaced by ibuprofen, introduced as polyelectrolyte layer. Zeta-potential, TGA and FT-IR spectroscopy were measured after the addition of each polyelectrolyte layer, confirming the occurrence of the stepwise deposition. In addition, the in vitro bioactivity and the ability to modulate the release of the cargo were evaluated. The polyelectrolyte coated-MBGs were proved to retain the peculiar ability to induce hydroxyapatite formation after 7 days of soaking in Simulated Body Fluid. Both copper ions and ibuprofen were co-released over time, showing a sustained release profile up to 14 days and 24 h, respectively, with a significantly lower burst release compared to the bare MBG particles

Phosphorylation of rat brain calpastatins by protein kinase C

AbstractCalpastatin, the natural inhibitor of calpain, is present in rat brain in multiple forms, having different molecular masses, due to the presence of one (low Mr form) or four (high Mr form) repetitive inhibitory domains. Recombinant and native calpastatin forms are substrates of protein kinase C, which phosphorylates a single serine residue at their N-terminus. Furthermore, both low and high Mr calpastatins are phosphorylated by protein kinase C at the same site. These calpastatin forms are phosphorylated also by protein kinase A, although with a lower efficiency. The incorporation of a phosphate group determines an increase in the concentration of Ca2+ required to induce the formation of the calpain-calpastatin complex. This effect results in a large decrease of the inhibitory efficiency of calpastatins. We suggest that phosphorylation of calpastatin represents a mechanism capable to balance the actual amount of active calpastatin to the level of calpain to be activated

Trattamento dell’iperuricemia nel paziente nefropatico: è giunto il momento di agire?

Numerosi studi epidemiologici condotti nella popolazione generale indicano che l\u2019iperuricemia si associa ad un incremento del rischio di sviluppare insufficienza renale. Inoltre, tra i soggetti che sono gi\ue0 affetti da una malattia renale cronica (MRC), l\u2019iperuricemia si associa sia ad una pi\uf9 rapida progressione di malattia sia ad un significativo incremento della mortalit\ue0 e degli eventi cardiovascolari. Tuttavia, ad oggi il ruolo causale dell\u2019iperuricemia nel determinare l\u2019insorgenza e la progressione del danno renale e cardiovascolare non \ue8 ancora completamente accertato, per cui le indicazioni al trattamento farmacologico dell\u2019iperuricemia asintomatica nei pazienti con MRC sono ancora affidate all\u2019orientamento personale del singolo medico. Al fine di stabilire se sia possibile esprimere un orientamento clinico basato sull\u2019evidenza abbiamo eseguito un\u2019analisi comparativa degli studi prospettici che hanno valutato l\u2019impatto della terapia ipouricemizzante con inibitori della xantino ossidasi (IXAO) rispetto all\u2019insorgenza e alla progressione del danno renale. Inoltre, dal momento che in passato nei soggetti con funzionalit\ue0 renale ridotta il trattamento con IXAO \ue8 stato associato ad un elevato rischio di tossicit\ue0, abbiamo analizzato la tossicit\ue0 di questi farmaci per vari gradi compromissione della funzione renale riassumendo indicazioni, controindicazioni e dosi consigliate nei pazienti affetti da MRC. In fine, a conclusione della nostra analisi abbiamo elaborato un algoritmo finalizzato ad orientare le decisioni cliniche in merito al trattamento dell\u2019iperuricemia nei soggetti affetti da MRC.Numerous epidemiological studies conducted in the general population indicate that hyperuricemia is associated with an increased risk of developing renal failure. Moreover, among those subjects who are already suffering from chronic kidney disease (CKD), hyperuricemia is associated with a more rapid progression of disease besides with an increased risk of mortality and cardiovascular events. However, to date, the causal role of hyperuricaemia in determining the onset and progression of cardiovascular and renal damage is not yet fully established. Therefore the indications for pharmacological treatment of hyperuricemia (and particulary of asymptomatic hyperuricemia) in patients with CKD are still assigned to the personal orientation of the physician. In order to produce an evidence-based clinical appraisal on this topic, we performed a comparative analysis that included all the prospective studies that have evaluated the impact of treatment with xanthine oxidase inhibithors (XOI) with respect to the onset and progression of CKD. Moreover, since in the past the treatment with XOI was associated with a high risk of toxicity in patients with impaired renal function, we analyzed the toxicity of these drugs for various degrees of renal function impairment summarizing indications, contraindications and recommended doses in patients affected by CKD. In the end, as conclusion of our analysis, we propose an algorithm aimed at guiding the clinical decisions about the treatment of hyperuricemia in patients with CKD

Natural history and risk factors for diabetic kidney disease in patients with T2D: lessons from the AMD-annals

The Associazione Medici Diabetologi (AMD) annals initiative is an ongoing observational survey promoted by AMD. It is based on a public network of about 700 Italian diabetes clinics, run by specialists who provide diagnostic confirmation and prevention and treatment of diabetes and its complications. Over the last few years, analysis of the AMD annals dataset has contributed several important insights on the clinical features of type-2 diabetes kidney disease and their prognostic and therapeutic implications. First, non-albuminuric renal impairment is the predominant clinical phenotype. Even though associated to a lower risk of progression compared to overt albuminuria, it contributes significantly to the burden of end-stage renal disease morbidity. Second, optimal blood pressure control provides significant but incomplete renal protection. It reduces albuminuria but there may be a J curve phenomenon with eGFR at very low blood pressure values. Third, hyperuricemia and diabetic hyperlipidemia, namely elevated triglycerides and low HDL cholesterol, are strong independent predictors of chronic kidney disease (CKD) onset in diabetes, although the pathogenetic mechanisms underlying these associations remain uncertain. Fourth, the long-term intra-individual variability in HbA1c, lipid parameters, uric acid and blood pressure plays a greater role in the appearance and progression of CKD than the absolute value of each single variable. These data help clarify the natural history of CKD in patients with type 2 diabetes and provide important clues for designing future interventional studies

Hybrid injectable platforms for the in situ delivery of therapeutic ions from mesoporous glasses

Copper-containing bioactive glasses (Cu-MBGs) are attracting increasing interest as multifunctional agents for hard and soft tissue healing due to the ability of released copper ions to stimulate osteogenesis as well as angiogenesis and to impart anti-bacterial properties. The conjugation of these nanomaterials with a vehicle phase based on thermosensitive hydrogels represents an effective strategy to design non-invasive injectable devices for the in situ delivery of therapeutic ions from MBGs. In this contribution, Cu-containing MBGs were prepared by an aerosol-assisted spray-drying method (MBG_Cu 2%_SD) in the form of microspheres (surface area of ca 220m2 g−1) and through a sol-gel synthesis (MBG_Cu 2% _SG) in the form of spheroidal nanoparticles (surface area above 700m2 g−1). Both Cu-containing samples were able to release copper ions, although with different rates and percentage release. MBG_Cu 2%_SG released the total incorporated amount of Cu ions with a faster kinetics compared to MBG_Cu 2%_SD, that released approximately the 60% of copper. Cu-MBGs were incorporated with a final concentration of 20 mg/mL into a thermosensitive sol-gel system consisting of a novel amphiphilic poly(ether urethane) based on a commercialy available Poloxamer 407 (P407), with improved gelation ability, mechanical strength and stability in aqueous solution with respect to native P407. Cu-MBG-loaded hydrogels were characterised in terms of sol-to-gel transition temperature and time, injectability and stability in aqueous environment at 37 °C. The hybrid formulations showed fast gelation in physiological conditions (1 mL underwent complete sol-to-gel transition within 3–5 min at 37 °C) and injectability in a wide range of temperatures (5–37 °C) through different needles (inner diameter in the range 0.6–1.6 mm)