Hotspots of biogeochemical activity linked to aridity and plant traits across global drylands.

Perennial plants create productive and biodiverse hotspots, known as fertile islands, beneath their canopies. These hotspots largely determine the structure and functioning of drylands worldwide. Despite their ubiquity, the factors controlling fertile islands under conditions of contrasting grazing by livestock, the most prevalent land use in drylands, remain virtually unknown.

Species-specific interference exerted by the shrub Cistus clusii Dunal in a semi-arid Mediterranean gypsum plant community.

Background: The gypsovag shrub Cistus clusii is locally dominant in semi-arid gypsum plant communities of North-Eastern Spain. This species commonly grows in species-poor patches even though it has nurse potential, suggesting interference on neighbouring species. Other Cistus species exert a chemically mediated interference on plant communities, suggesting that it might be a common phenomenon in this genus.

Evidence for chemical interference effect of an allelopathic plant on neighboring plant species: A field study.

Many studies have reported the phytotoxicity of allelopathic compounds under controlled conditions. However, more field studies are required to provide realistic evidences for the significance of allelopathic interference in natural communities. We conducted a 2-years field experiment in a semiarid plant community (NE Spain).

Sensitivity of Enzymatic Toxins from Corneal Isolate of Acanthamoeba Protozoan to Physicochemical Parameters.

Acanthamoeba is a free-living amoeba that causes severe corneal infection (Acanthamoeba keratitis) and produces a variety of extracellular enzymes, called exoproteome. Since physicochemical characters are suggested being associated with therapeutic profile and clinical severity of the infection, we investigated the physicochemical properties of proteolysis mediated by amoebic exoproteome. Corneal scraping was collected from a patient who showed typical symptoms of acute Acanthamoeba keratitis.

Therapeutic agents and biocides for ocular infections by free-living amoebae of Acanthamoeba genus.

Acanthamoeba keratitis is a sight-threatening infectious disease. Resistance of the cystic form of the protozoan to biocides and the potential toxicity of chemical compounds to corneal cells are the main concerns related to long-term treatment with the clinically available ophthalmic drugs. Currently, a limited number of recognized antimicrobial agents are available to treat ocular amoebic infections.

Enhancing seedling production of native species to restore gypsum habitats.

Gypsum habitats are widespread globally and are important for biological conservation. Nevertheless, they are often affected by human disturbances and thus require restoration. Sowing and planting have shown positive results, but these actions are usually limited by the lack of native plant material in commercial nurseries, and very little information is available on the propagation of these species.

Cytotoxic activity and degradation patterns of structural proteins by corneal isolates of Acanthamoeba spp.

Background: Proteolytic enzymes secreted by trophozoites (amoebic secretome) are suggested as the main virulence factor involved in the severity of Acanthamoeba keratitis. The degradation profile of the main glycoprotein components of anterior and posterior portions of the cornea and the cytopathic effect of secretomes on endothelial cells by contact-independent mechanism were evaluated.

Methods: Trophozoites were isolated primarily from corneal tissue samples (n = 11) and extracellular proteins were collected from axenic cell culture supernatants.

Antimicrobial action of biguanides on the viability of Acanthamoeba cysts and assessment of cell toxicity.

Purpose: To assess dose- and concentration-dependent rates of biguanides on the viability of Acanthamoeba cysts isolated from severe ulcerative keratitis, and to correlate cysticidal activites with cytotoxic profiles in corneal and endothelial cells.

Methods: Cysticidal activities of polyhexamethylene biguanide and chlorhexidine digluconate were evaluated in the Acanthamoeba castellanii strain and clinical isolates of Acanthamoeba spp obtained from two severe and recurrent cases of ulcerative keratitis. The molecular characterization of protozoa used in the experimental assays was performed by sequencing reactions of the 18S rDNA gene.

Assessing efficacy of combined riboflavin and UV-A light (365 nm) treatment of Acanthamoeba trophozoites.

Purpose: To assess the Acanthamoeba trophozoite viability in vitro and treatment of Acanthamoeba keratitis in a hamster model using ultraviolet light A (UV-A) and riboflavin (B2).

Methods: A sample of Acanthamoeba sp. cultured was transferred to a 96-well plate and exposed to B2 and the UV-A light (365 nm wavelength) at a power density of 3 mW/cm(2), 8 mm spot diameter, for 30 minutes.

Serine-like proteolytic enzymes correlated with differential pathogenicity in patients with acute Acanthamoeba keratitis.

Acute ocular infection due to free-living amoebae of the genus Acanthamoeba is characterized by severe pain, loss of corneal transparency and, eventually, blindness. Proteolytic enzymes secreted by trophozoites of virulent Acanthamoeba strains have an essential role in the mechanisms of pathogenesis, including adhesion, invasion and destruction of the corneal stroma. In this study, we analysed the relationship between the extracellular proteases secreted by clinical isolates of Acanthamoeba and the clinical manifestations and severity of disease that they caused.

Competitive sports for children and adolescents: should an electrocardiogram be required in the pre-participation physical examination?

The growing number of children and adolescents, aged 7 to 17 years, that participate in competitive sports requires preventive medical care. The pre-participation physical examination (PPE) requires appropriate medical knowledge to insure safe medical clearance. Recent sudden death events related to sports practice have raised doubts concerning the need for a medical evaluation based on medical tests, which due to the delay in its implementation may result in demotivation and abandonment of the sports practice.

Differential effects of alpha-helical and beta-hairpin antimicrobial peptides against Acanthamoeba castellanii.

In this work we evaluated the ability of different types of antimicrobial peptides to promote permeabilization and growth inhibition of Acanthamoeba castellanii trophozoites, which cause eye keratitis. We used cationic alpha-helical peptides P5 and P6, corresponding to the N-terminus of the pore-forming protein from Triatoma infestans, a blood-sucking insect, and a beta-hairpin amphipathic molecule (gomesin), of the spider Acanthoscurria gomesiana haemocytes. A.

Twenty years of acanthamoeba keratitis.

Purpose: We described the rate of Acanthamoeba keratitis (AK) in a referral eye center in São Paulo, Brazil, through a retrospective review of clinical and laboratorial records of patients over 2 decades.

Methods: From 1987 to 2006, a total of 581 requests for amoebic laboratory workup in cases of infectious keratitis were investigated. Statistical analyses were applied to analyze a tendency of AK cases.

Corneal graft survival after therapeutic keratoplasty for Acanthamoeba keratitis.

Purpose: To describe corneal graft survival and visual outcome after therapeutic penetrating keratoplasty in patients with Acanthamoeba keratitis (AK) that is unresponsive to clinical treatment.

Methods: Retrospective study. Thirty-two patients with AK who underwent therapeutic penetrating keratoplasty (tPK) from August 1996 to August 2005 were included.

Occurrence and diversity of Legionellaceae in polar lakes of the Antarctic peninsula.

Legionellaceae is a family of gram-negative, mesophilic, and facultative intracellular parasitic bacteria that inhabits freshwater environments. In this article, the Legionella population of water samples from the North and South Lake, located close to the Brazilian Scientific Station on King George Island, Keller Peninsula, Antarctica has been characterized. Culture onto selective medium and a independent-culture method were applied to the samples.

Phylogenetic study of legionella species in pristine and polluted aquatic samples from a tropical Atlantic forest ecosystem.

Legionella species are ubiquitous bacteria in aquatic environments. To examine the effect of anthropogenic impacts and physicochemical characteristics on the Legionellaceae population, we collected water from two sites in the Itanhaém River system in the Atlantic Forest of Brazil. One sample was collected from an upstream pristine region, the other from a downstream estuarine region moderately affected by untreated domestic sewage.

[Diagnosis of Acanthamoeba corneal infection by impression cytology: case report].

To describe three cases of corneal infection due to Acanthamoeba sp in which was possible to detect Acanthamoeba sp cysts by the corneal impression cytology technique. Three patients referred to the External Eye Disease Laboratory in 2004 with superficial corneal alterations were submitted to corneal specimen collection by impression cytology filter paper to investigate the presence of Acanthamoeba sp cysts. Two impression cytology samples were obtained from each patient and were stained by PAS, hematoxylin and Papanicolaou.

Levels of lipoprotein (a) in pulmonary arterial hypertension.

We compared the levels of lipoprotein (a) in 48 Caucasian patients with pulmonary arterial hypertension, comprising 32 females and 16 males, aged 28.0 +/- 12.0 years, with a range from 4 through 52 years, with 48 normal Caucasian subjects matched for age and sex.

Random amplified polymorphic DNA profiles as a tool for the characterization of Brazilian keratitis isolates of the genus Acanthamoeba.

The genus Acanthamoeba comprises free-living amebae identified as opportunistic pathogens of humans and other animal species. Morphological, biochemical and molecular approaches have shown wide genetic diversity within the genus. In an attempt to determine the genetic relatedness among isolates of Acanthamoeba we analyzed randomly amplified polymorphic DNA (RAPD) profiles of 11 Brazilian isolates from cases of human keratitis and 8 American type culture collection (ATCC) reference strains.

[Agenesis of the right pulmonary artery with severe pulmonary hypertension, attenuated by surgical correction].

A 22 months old infant with agenesis of right pulmonary artery, without other associated congenital heart defects, is reported. Reconstruction of pulmonary arteries by connecting them through a 7mm Goretex tube was performed, with clear clinical improvement in view of disappearance of signs of cardiac insufficiency and of hypoxemia. Contralateral pulmonary hypertension, at systemic level, decreased to 77% in the immediate postoperative period.

[Ischemic cardiomyopathy in a child. Case report with accentuated coronary disease].

Ischemic cardiomyopathy in childhood is related with congenital and acquired pathologies which could lead to serious cardiac sequelae as myocardial infarction and sudden death. Unfortunately, when coronary artery malformations are excluded, it is difficult in some cases to be completely certain on the etiology of the arterial coronary disease, due the lack of pathognomonic diagnostic tests. Case report of 6 year old child, with severe coronary artery disease: aneurysm of main branch of left coronary artery; left anterior descending branch and right coronary artery occlusions with accentuated myocardial dysfunction.