TIA-like presentations of cerebral amyloid angiopathy

Transient focal neurological episodes (TFNEs ) are transient ischemic attack (TIA)-like episodes that may occur in patients with cerebral amyloid angiopathy (CAA). The duration of TFNEs is typically similar to TIAs with most symptoms resolving in minutes. Symptoms, similar to those of TIAs include sensory or visual disturbances, motor weakness and language impairment and there may be limb jerking or associated headache. TFNEs have a more gradual onset and tend to spread slowly to contiguous body parts like a migraine aura. TFNEs may occur repeatedly throughout the day and attacks may continue over several months. TFNEs are typically associated with focal cortical subarachnoid hemorrhage or with focal cortical superficial siderosis. They may also be seen in patients with CAA-related lobar hemorrhage, microhemorrhage or leukoencephalopathy. Migraine prophylactic agents such as verapamil and topiramate may be useful in stopping frequent recurrent TFNEs. TFNEs are an under-recognized cause of apparent TIAs. It is important to keep TFNEs in the differential diagnosis when a patient presents with a presumed TIA as thrombolysis or anticoagulation is relatively contraindicated in CAA. Gradient echo MRI should be performed to exclude microhemorrhages when TFNEs are suspected. Clinicians most frequently associate cerebral amyloid angiopathy (CAA) with intracerebral hemorrhage or with a clinical picture of vascular cognitive impairment.1 There have however, been increasing clinical reports documenting that CAA may cause a variety of acute clinical neurological manifestations.2 Although these phenomena are superficially similar to TIAs and may be mistaken for them, they have clinical time profiles and progressions that can distinguish them from TIAs clinically. They appear to be caused by different manifestations of the complications of CAA and are now known as transient focal neurological episodes (TFNE).2,3 CAA frequency increases with age with approximately 50 % of individuals over the age of 75 being affected. The exact cause of CAA remains uncertain however increased production and/or decreased breakdown of amyloid proteins may have a role. CAA predominantly affects occipital regions of the brain followed by frontal and temporal areas. Cerebellar vessels are less commonly affected.3The Boston criteria is the current standard criteria for diagnosis of CAA. In this review, we attempt to classify and describe the different causes of TFNE’s in CAA.peer-reviewe

Silta mill-"Antigone" ta’ Sofokle

Ġabra ta’ poeżiji u proża li tinkludi: Ħajki ta’ Josette Attard – Din l-għanja tiegħi ta’ Rena Balzan – Fl-irdum fejn jidwi ta’ Charles Bezzina – Naqa’ biss ta’ Ġorġ Borg – Gambrinu, 7.45 a.m. ta’ Norbert Bugeja – Għadam ta’ Joseph Buttigieg – Tħarisx biss fil-wiċċ ta’ John Caruana – Petra ta’ Priscilla Cassar – Mhux iżjed dan il-pajjiż tiegħi ta’ Victor Fenech – Twieqi magħluqa ta’ Maria Grech Ganado – Joseph quddiem ir-ritratt ta’ sieħbu jitfarrak ta’ Adrian Grima – Ta’ l-ilma l-fruntieri tiegħek ta’ Simone Inguanez – Għall-kaċċa tal-grejtwajt ta’ Daniel Massa – Ftit weraq mis-Slovenja ta’ Immanuel Mifsud – Dak li kien ta’ Achille Mizzi – Wassalni ta’ Anna Pullicino – Tamiet fiergħa ta’ Patrick Sammut – Fost l-isbaħ jiem ta’ Lillian Sciberras – Kelma ta’ Marcel Zammit Marmarà – Lill-Imdina żagħżugħa ta’ Joe Zammit Tabona – Sodda ta’ l-ilma ta’ Clare Azzopardi – Kurċifiss ta’ Paul P. Borg – Mera mkissra ta’ Lina Brockdorff – No(ra)vella ta’ Joe Friggieri – L-abbati ta’ Henry Holland – L-eħrex ġurnata tal-gwerra ta’ Maurice Mifsud Bonnici – Marija ta’ Lino Spiteri – Ikla ta’ Trevor Żahra – Il-mara midinba ta’ Albert Camus, traduzzjoni ta’ Toni Aquilina – Silta mill-"Antigone" ta’ Sofokle, traduzzjoni ta’ Victor Xuereb.peer-reviewe

Organic carbon stabilization in temperate paddy fields and adjacent semi-natural forests along a soil age gradient

Rice paddy soils have high organic carbon (OC) storage potential, but predicting OC stocks in these soils is difficult due to the complex OC stabilization mechanisms under fluctuating redox conditions. Especially in temperate climates, these mechanisms remain understudied and comparisons to OC stocks under natural vegetation are scarce. Semi-natural forests could have similar or higher OC inputs than rice paddies, but in the latter mineralization under anoxic conditions and interactions between OC and redox-sensitive minerals (in particular Fe oxyhydroxides, hereafter referred to as Fe oxides) could promote OC stabilization. Moreover, management-induced soil redox cycling in rice paddies can interact with pre-existing pedogenetic differences of soils having different degrees of evolution. To disentangle these drivers of soil OC stocks, we focused on a soil age gradient in Northern Italy with a long (30 + years) history of rice cultivation and remnant semi-natural forests. Irrespective of soil age, soils under semi-natural forest and paddy land-use showed comparable OC stocks. While, in topsoil, stocks of crystalline Fe and short-ranged Fe and Al oxides did not differ between land-uses, under paddy management more OC was found in the mineral-associated fraction. This hints to a stronger redox-driven OC stabilization in the paddy topsoil compared to semi-natural forest soils that might compensate for the presumed lower OC inputs under rice cropping. Despite the higher clay contents over the whole profile and more crystalline pedogenetic Fe stocks in the topsoil in older soils, OC stocks were higher in the younger soils, in particular in the 50–70 cm layer, where short-range ordered pedogenetic oxides were also more abundant. These patterns might be explained by differences in hydrological flows responsible for the translocation of Fe and dissolved OC to the subsoil, preferentially in the younger, coarse-textured soils. Taken together, these results indicate the importance of the complex interplay between redox-cycling affected by paddy-management and soil-age related hydrological properties

Organic carbon stabilization in temperate paddy fields and adjacent semi-natural forests along a soil age gradient

Rice paddy soils have high organic carbon (OC) storage potential, but predicting OC stocks in these soils is difficult due to the complex OC stabilization mechanisms under fluctuating redox conditions. Especially in temperate climates, these mechanisms remain understudied and comparisons to OC stocks under natural vegetation are scarce. Semi-natural forests could have similar or higher OC inputs than rice paddies, but in the latter mineralization under anoxic conditions and interactions between OC and redox-sensitive minerals (in particular Fe oxyhydroxides, hereafter referred to as Fe oxides) could promote OC stabilization. Moreover, management-induced soil redox cycling in rice paddies can interact with pre-existing pedogenetic differences of soils having different degrees of evolution. To disentangle these drivers of soil OC stocks, we focused on a soil age gradient in Northern Italy with a long (30 + years) history of rice cultivation and remnant semi-natural forests. Irrespective of soil age, soils under semi-natural forest and paddy land-use showed comparable OC stocks. While, in topsoil, stocks of crystalline Fe and short-ranged Fe and Al oxides did not differ between land-uses, under paddy management more OC was found in the mineral-associated fraction. This hints to a stronger redox-driven OC stabilization in the paddy topsoil compared to semi-natural forest soils that might compensate for the presumed lower OC inputs under rice cropping. Despite the higher clay contents over the whole profile and more crystalline pedogenetic Fe stocks in the topsoil in older soils, OC stocks were higher in the younger soils, in particular in the 50–70 cm layer, where short-range ordered pedogenetic oxides were also more abundant. These patterns might be explained by differences in hydrological flows responsible for the translocation of Fe and dissolved OC to the subsoil, preferentially in the younger, coarse-textured soils. Taken together, these results indicate the importance of the complex interplay between redox-cycling affected by paddy-management and soil-age related hydrological properties

Redox-driven colloidal mobility and its effects on carbon cycling in temperate paddy soils

Rice paddy soils are known to represent a large proportion of global terrestrial carbon (C) stocks (ca.10 Pg), accumulating organic C in the topsoil due to cultivation under submerged conditions. Apart from the limited mineralization under anoxic soil conditions resulting from frequent field flooding, other mechanisms involving the dynamic interactions between organic C and redox-active minerals particularly Fe (oxy)hydroxides, together with the transport of organic C to deep mineral horizons, can lead to long-term C stabilization. Our previous studies have shown that up to 30-50 g m-2 of dissolved organic C (DOC, defined as <450 nm) and 25-40 g m-2 of Fe2+ may be mobilized and translocated into the subsoil over a rice cropping season in temperate rice paddies, contributing to an increase in belowground C stocks. However, little is yet know on influence of frequent redox fluctuations on the contribution of colloidal organo-mineral associations to C mobilization and accrual in paddy subsoils. We hypothesized that (i) redox fluctuations may lead to an overall increase in colloid dispersion (via reductive dissolution of Fe oxides, changes in soil pH, as well as neoformation of colloidal organo-mineral associations), and that (ii) colloidal mobility may represent an important C input to paddy subsoils. In order to evaluate the effects of redox fluctuations on colloid dynamics in situ, water-dispersible fine colloids (WDFC) were isolated from soils collected from different horizons along two profiles opened in adjacent plots under long-term paddy (P) and non-paddy (NP) management in NW Italy. Moreover, WDFC were also isolated from anaerobically-incubated topsoil samples to evaluate the changes in colloid dispersion under reducing conditions as a function of management. Colloidal size-fractionation and their elemental compositions were evaluated by asymmetric flow field-flow fractionation (AF4) coupled with OCD or ICP-MS. Our results evidenced that redox cycling favours colloidal stability in the topsoils, with a preferential dispersion of the smallest-sized colloidal C (<30 nm and 30-240 nm fractions), even though larger-sized colloidal C (>240 nm) contributes predominantly to the WDFC. Consequently, under long-term paddy management colloidal dispersion and transport along the soil profile were probably responsible for the lower amounts of colloidal C (and Fe) observed in the Ap topsoil horizons of P with respect to NP, as well as for the significant accumulation of colloidal C in correspondence with the Brd subsoil horizons just beneath the plough pan. These illuvial horizons were also particularly rich in small-sized (30-240 nm) colloidal Fe, Al and Si possibly due to mineral phase changes induced by redox fluctuations. Our findings therefore indicate that downward mobilization of colloidal C associated with Fe (hydr)oxides (e.g. coprecipitates) or small aluminosilicate minerals, rather than dissolved organic C, may represent an important process driving organic C accrual in paddy subsoils. However, further insights are still required to entangle the contribution of the different mechanisms involved

Redox-driven changes in water-dispersible colloids and their role in carbon cycling in hydromorphic soils

Redox fluctuations in hydromorphic soils can influence ecosystem functions by altering the cycling of organic carbon (OC) and other elements in both the aqueous and solid phases throughout the soil profile. Most studies focusing on the mobility of dissolved OC in rice paddy soils have often disregarded the contribution of colloidal particles. We provide a detailed chemical and size-related characterization of water-dispersible soil colloids and their depth distribution in two soil profiles under long-term temperate paddy and non-paddy management, by asymmetric flow field-flow fractionation. Anoxic conditions enhanced colloid dispersion with a preferential release of the finer colloid fractions (5 and 4-fold increase in the < 30 nm and 30–240 nm fractions, respectively). The mobility of OC-rich, iron (Fe) and aluminium (hydr)oxide and aluminosilicate colloids along the soil profile was probably responsible for their depletion in the topsoil and a corresponding accumulation in the deeper illuvial horizons compared to the non-paddy soil. However, the release, percolation and subsequent reoxidation of Fe2+ was also shown to be a plausible mechanism leading to the formation of fine colloids in the subsoil. Redox-driven changes in colloid distribution were also linked to the differences in OC and pedogenetic Fe stocks in these two agro-ecosystems

Genetic aspects of stroke: Human and experimental studies

As one of the leading causes of death within both the developed and developing world, stroke is a worldwide problem. Risk factors can be identified and controlled at the level of lifestyle changes; however, genetic components of stroke have yet to be identified. The identification of such genetic components is critical in the understanding, diagnosis, and treatment of stroke in the future. This review focuses on the genetic determinants of stroke in both human and experimental systems. Mendelian disorders, candidate genes, and twin studies provide evidence for a strong genetic component of stroke. Genome-wide scanning in both human and animal models has led to the identification of regions of the genome that contain genes for stroke susceptibility and sensitivity. Animal models of stroke allow for environmental control and genetic homogeneity, not possible within a human population, and therefore are essential for the dissection of this complex, multifactorial disorder. Future genetic and genomic strategies and their role in ultimate causative gene identification are discussed

Stroke aetiology and predictors of outcome in patients with heart failure and acute stroke: a 10-year follow-up study

Aims The aim of this study was to investigate stroke aetiology and assess the predictors of early and late outcome in patients with heart failure (HF) and acute stroke. Methods and results A total of 2904 patients, admitted between 1993 and 2010, were regularly followed up at months 1, 3, and 6, and yearly thereafter up to 10 years. There were 283 (9.7%) stroke patients with HF; atrial fibrillation (AF) was present in 144 (50.9%) of them. Stroke aetiology in patients with HF and AF was mainly cardioembolism (82%) regardless of HF aetiology. In contrast, in the 139 non-AF patients with HF, the stroke mechanism was associated with the aetiology of HF: valvular heart disease and dilated cardiomyopathy were related to cardioembolism in 60% and 66.7% of patients, respectively, whereas HF due to coronary artery disease or hypertension was associated with atherosclerotic and lacunar stroke in 40.8% and 61.5%, respectively. In the overall population, HF was an independent predictor of 10-year mortality [hazard ratio = 1.54, 95% confidence interval (CI) 1.29-1.83; P < 0.001]. Probability of 10-year survival was 19.4% (95% CI 14.5-23.5) for HF patients and 44.1% (95% CI 41.4-46.8) for non-HF patients (P < 0.0001). Ten-year mortality in HF patients was associated with functional class of HF, age, diabetes, stroke severity, and in-hospital aspirin use. The presence of AF in HF stroke patients did not influence 10-year survival and composite cardiovascular events (P = 0.429 and P = 0.406, respectively). Conclusions In patients with HF, stroke aetiology is influenced by the presence of AF and the underlying cause of HF. Early and late stroke outcome is associated with HF severity but not with the presence of AF