Viral nano-hybrids for innovative energy conversion and storage schemes

Typical rod-like viruses (the Tobacco Mosaic Virus (TMV) and the Bacteriophage M13) are biological nanostructures that couple a 1D mono-dispersed morphology with a precisely defined topology of surface spaced and orthogonal reactive domains. These biogenic scaffolds offer a unique alternative to synthetic nano-platforms for the assembly of functional molecules and materials. Spatially resolved 1D arrays of inorganic-organic hybrid domains can thus be obtained on viral nano-templates resulting in the functional arrangement of photo-triggers and catalytic sites with applications in light energy conversion and storage. Different synthetic strategies are herein highlighted depending on the building blocks and with a particular emphasis on the molecular design of viral-templated nano-interfaces holding great potential for the dream-goal of artificial photosynthesis.

Catalytic oxygen production mediated by smart capsules to modulate elastic turbulence under a laminar flow regime

Liquid flow in microchannels is completely laminar and uniaxial, with a very low Reynolds number regime and long mixing lengths. To increase fluid mixing and solubility of reactants, as well as to reduce reaction time, complex three-dimensional networks inducing chaotic advection have to be designed. Alternatively, turbulence in the liquid can be generated by active mixing methods (magnetic, acoustic waves, etc.) or adding small quantities of elastic materials to the working liquid. Here, polyelectrolyte multilayer capsules embodying a catalytic polyoxometalate complex have been suspended in an aqueous solution and used to create elastic turbulence and to propel fluids inside microchannels as an alternative to viscoelastic polymers. The overall effect is enhanced and controlled by feeding the polyoxometalate-modified capsules with hydrogen peroxide, H2O2, thus triggering an on-demand propulsion due to oxygen evolution resulting from H2O2 decomposition. The quantification of the process is done by analysing some structural parameters of motion such as speed, pressure, viscosity, and Reynolds and Weissenberg numbers, directly obtained from the capillary dynamics of the aqueous mixtures with different concentrations of H2O2. The increases in fluid speed as well as the capsule-induced turbulence effects are proportional to the H2O2 added and therefore dependent on the kinetics of H2O2 dismutation.

Prescriptions of NSAIDs to patients undergoing third molar surgery : an observational, prospective, multicentre survey

BACKGROUND AND OBJECTIVES

Surgical extraction of an impacted third molar is generally followed by acute post-operative pain that has been shown to be primarily inflammatory. Thus, use of NSAIDs in this context is appropriate and has been shown to be effective. Several drugs are employed for this purpose, but no information exists on the reasons why preference is given to one rather than another. The principal objective of this study was to evaluate the pattern of administration of NSAIDs in patients undergoing surgery for impacted third molar extraction. The study also aimed to collect information on the efficacy, onset and duration of the analgesic effect of routinely prescribed NSAIDs and to assess the duration of treatment with these drugs and their tolerability.

METHODS

This was an observational, multicentre, prospective survey. A total of 616 patients (38% male and 62% female) from the Italian Stomatology Clinics of the Universities of Bologna, Brescia, Cagliari, Chieti, Pavia, Pisa, Siena and Varese and from the Department of Oral and Maxillo-Facial Surgery of Semmelweis University, Budapest, were eligible for the study. Patients were evaluated over the 7 days following surgical extraction. NSAIDs were prescribed according to the normal prescribing habits of the centre and physician involved. The main outcomes of interest in the survey were the efficacy, onset and duration of analgesic effect, duration of therapy, and tolerability of the NSAIDs prescribed.

RESULTS

Nimesulide was the most prescribed NSAID (68%), followed by diclofenac, ketoprofen and ibuprofen. Because of the low proportion of patients receiving other NSAIDs, these patients were considered a single treatment group for evaluation purposes. Nimesulide, especially when given before patients started experiencing pain after surgery, was more effective than other NSAIDs in reducing the severity of pain on the day of surgery, in delaying the time to maximum intensity of pain, in providing complete pain relief and in prolonging the duration of analgesic effect on the day of surgery. These results are consistent with the known anti-inflammatory and analgesic actions of nimesulide and with the important role of inflammation in the onset of pain after this type of surgery.

CONCLUSION

These results confirm nimesulide as an effective reference drug for the treatment of post-operative dental pain and show that it has a positive benefit/risk profile in this setting.

[Kidney diseases with chronic renal failure in the Italian renal biopsy registries]

The prevalence of chronic renal failure (CRF) at the time of kidney biopsy ranges between 5% and 37% in different renal biopsy registries. This wide variability is mainly dependent on the different definitions of CRF. In the period 1998-2006, the Triveneto Renal Biopsy Registry recorded 816 cases with CRF (defined as serum creatinine persistently > or =1.5 mg/dL), accounting for a prevalence of 27%. At the time of biopsy, the average age and glomerular filtration rate were 54 years and 41 mL/min, respectively; 70% of CRF patients are men and the prevalence of CRF increases with age. IgA nephropathy (IgAN) is the main histological form of glomerulonephritis, accounting for 23% of all cases of CRF. However, in subjects older than 65 years, membranous glomerulonephritis (MG) exceeds IgAN, thus becoming the main diagnosis in elderly patients with renal impairment. With a cutoff value for proteinuria of 3 g/day, the main diagnoses in cases with proteinuria below and above the cutoff are IgAN and MG, respectively. IgAN remains the main histological form of nephropathy throughout all levels of renal failure. These data confirm the findings of the Italian Registry of Renal Biopsies, but correspond only in part with data from other registries. The differences can to a certain extent be explained by the different criteria for the definition of renal impairment, patient selection, and differences in diagnosis among registries.

Posttransplant recurrence of proteinuria in a case of focal segmental glomerulosclerosis associated with WT1 mutation

Posttransplant recurrence of inherited focal segmental glomerulosclerosis (FSGS) is still an enigma owing to the evident paradox of the molecular origin of proteinuria. A young girl with FSGS for WT1 mutation (IVS9+4C>T) and Frasier syndrome received a renal transplant at the age of 11 years. After an initial good outcome with recovery of renal function, proteinuria re-appeared after 7 days and steadily increased up to a nephrotic range. Determination of plasma permeability activity showed concomitant high Palb (0.7). At this point, plasmapheresis was started and after nine cycles with 1500 mL exchange and albumin re-infusion, proteinuria decreased to normal range and is still normal after 3 years. This is the first description of posttransplant recurrence of proteinuria in Frasier syndrome that should be included in potential outcome of renal transplant in this category of patients. This observation confirms the concept that recurrence of proteinuria may occur in inherited forms of FSGS so far reported only for patients carrying NPHS2 mutations and reinforces the idea on multifactorial origin of the disease.

[The pathogenetical mechanisms of glomerular proteinuria.]

Although the pathologic mechanisms responsible for glomerular proteinuria have not been completely clarified, yet, it has become evident that structural and functional abnormalities of podocytes play an early and important role. These data come from recent studies analyzing podocyte behaviour in cell culture, in-depth clinical researches, the application of survey techniques on isolated glomeruli, proteomic studies on particular aspects of circulating factors. For most glomerulopathies, whether primary or secondary, podocytes are often the first target for many pathogenetic mechanisms, which, unexpectedly, have the common characteristic of inducing tropism in podocytes. Hopefully, advances in glomerular podocyte research will better define clinical diseases, which we now classify according to a static description of the histological damage, thus perhaps mistaking causes and effects.

Circulating anti-actin and anti-ATP synthase antibodies identify a sub-set of patients with idiopathic nephrotic syndrome

Idiopathic nephrotic syndrome (iNS) with resistance or dependence to steroids is a common disease in children but in spite of an increasing clinical impact its pathogenesis is unknown. We screened for the presence of circulating antibodies against glomerular (podocytes, mesangium) and tubular cells (tubular epithelia) a cohort of 60 children with iNS including 8 patients with a familial trait of iNS or with proven mutation of NPHS1-NPHS2 and 12 with good sensitivity to steroids. Positive sera were found in 8 cases, all belonging to the category without familial trait/molecular defects. The targets of antibodies were characterized with Western blot and MALDI-Mass utilizing beta-hexyl cell extracts separated with two-dimensional electrophoresis. In all cases antibodies of the IgM class were directed against ATP synthase beta chain alone (4 cases) or in combination with actin (3 cases); one child presented IgG against aldose reductase. The clinical picture was nephrotic syndrome with steroid resistance or dependence and variable cyclosporin sensitivity; 3 patients developed end stage renal failure. The basic pathology picture was focal segmental glomerulosclerosis (FSGS) in 4 cases and mesangial proliferative glomerulonephrites with deposition of IgM in 2. Overall, patients with circulating auto-antibodies could not be readely differentiated on clinical grounds with the exception of 3 children who developed positivity for antinuclear antibodies during the follow-up. Affinity-purified IgM from one patient who underwent plasmapheresis for therapeutical pourposes (but not from a normal pool) induced proteinuria in Sprague-Dawley rats and concomitant human IgM deposition within glomeruli. This is the first report of circulating anti-actin/ATP synthase beta chain antibodies in a subset of patients with iNS. Both pathological significance and clinical impact given by the presence of these antibodies and the relationship with other conditions such as lupus-erythematosus, characterized by their presence, must be defined.

Humoral permeability factors in the nephrotic syndrome: a compendium and prospectus

The concept that increased glomerular albumin permeability in steroid-resistant nephrotic syndrome is induced by circulating humoral factors is not new. Zimmermann (1) was among the first to demonstrate that serum from a renal transplant patient with recurrent focal segmental glomerulosclerosis (FSGS) could provoke increased albumin excretion when infused in the aorta of intact rats. Unfortunately, the experiment was not easily reproducible, and the possibility that human serum could induce serum sickness in rats was a serious limitation of the original experiment. We now know that inhibitors of permeability activity are present in both normal human and rat serum (see below), which explains the difficulty in replicating the disease in intact animals. In 1974 Shalhoub (2) theorized that a disordered clone of T lymphocytes, present in both minimal change disease and FSGS, secreted a circulating lymphokine "toxic" to the glomerular barrier. In support of this hypothesis, Koyama et al (3) formed hybridomas from T cells from four patients with minimal change disease and three control subjects. The hybridomas of the patients produced a substance that induced proteinuria when injected intravenously into normal rats. However, the study utilized stimulated and not quiescent T cells, and therefore the relevance to the pathogenesis of FSGS is unknown. Hoyer and colleagues first described recurrence of idiopathic nephrotic syndrome after renal transplantation in 1972 (4). Numerous subsequent reports have established the rate of recurrence as being about 30%. Timely plasmapheresis associated with aggressive immunosuppression resolves the proteinuria and disease progression in a large proportion of cases (5). FSGS not only recurs after renal transplantation, but the diseased kidney can also recover when kept protected from the pathological milieu. Rea et al (6) demonstrated that kidneys from a donor with FSGS transplanted into two uremic recipients were free from proteinuria, and that renal function was normal after one year. Ethical and legal considerations aside, recurrence of FSGS after transplantation is strong evidence supporting the role of a humoral factor in the pathogenesis of the disease.

Modulation of incipient glomerular lesions in experimental diabetic nephropathy by hypotensive and subhypotensive dosages of an ACE inhibitor

A glomerular permeability defect occurs early in the course of type 1 diabetes and precedes the onset of microalbuminuria and renal morphological changes. Recently, ACE inhibitors have been shown to prevent loss of glomerular membrane permselective function, but the mechanism of this nephroprotective effect is still being debated. The objective of the present study was to evaluate the effects of hypotensive and subhypotensive dosages of the ACE inhibitor quinapril ex vivo and of its active metabolite quinaprilat in vitro on the glomerular albumin permeability (P(alb)) defect in the early phases of experimental diabetes. For the ex vivo study, six groups of male Wistar rats were evaluated for 4 weeks. One group served as a nondiabetic control (C); the other five groups were rendered diabetic and included untreated diabetic rats (D) and diabetic rats receiving quinapril at the dosages of 5 (DQ1), 2.5 (DQ2), 1.25 (DQ3), and 0.625 (DQ4) mg. kg(-1). day(-1). Dosage-dependent effects of quinapril on systolic blood pressure and the glomerular filtration rate were observed. In contrast, control of P(alb) in isolated glomeruli exposed to oncotic gradients, proteinuria, and glomerular and tubular hypertrophy was obtained with subhypotensive dosages (DQ3 and DQ4 groups) of the ACE inhibitor. In the in vitro study, quinaprilat reduced P(alb) significantly in concentration ranges from 10(-6) to 10(-14) mol/l compared with results in control glomeruli. The effect on P(alb) may have occurred by mechanisms different from kidney ACE inhibitor. These study results indicated that ACE inhibitor treatment prevents the early onset of the P(alb) defect in experimental diabetes. This effect seemed to occur independently of systemic or glomerular hemodynamic changes and, at least partially, from kidney ACE inhibition.

Inhibition of renal permeability towards albumin: a new function of apolipoproteins with possible pathogenetic relevance in focal glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) is a degenerative renal disease characterized by the accumulation of extracellular matrix and lipids within the glomerular tuft. It has been proposed that an abnormal renal permeabilization towards proteins induced by a putative plasma factor is, in some way, involved in the pathogenesis of the disease. In this paper, we measured the plasma permeability activity (Palb) in several sera of patients with FSGS and found a mean activity of 0.82+/-0.03 which means a marked increase compared to a mean Palb of 0.16+/-0.03 in normal controls. Coincubation of FSGS and normal serum reduced the permeability activity within the normal range; normal serum added to the incubation medium after the glomeruli had already been exposed to the FSGS serum had no effect, suggesting the presence of inhibitory substances with a direct effect on a circulating substrate. Finally, the antipermeability activity was retained when heated to 60 degrees C but not to 100 degrees C. By serial fractionations of normal serum and reported activity measurements at each step, five natural occurring inhibitors of albumin permeabilization were purified and characterized by matrix assisted laser desorption/ionization-mass spectrometry (MALDI-MS), as components of apolipoproteins (apo) (apo E2 and E4, apo L, the high Mr apo J and a 28 kDa fragment of apo A-IV). Coincubation of each apolipoprotein with FSGS serum inhibited permeability, but only apo J and apo E2 and E4 were found to be crucial for the process. In conclusion, we have purified from normal serum five inhibitors of permeability induced by FSGS serum, all corresponding to apolipoproteins. An imbalance between permeability factors and apolipoproteins may play a pathogenetic role in FSGS.