Tricuspid valve-in-valve procedure: a step-by-step guideline / Valve-in-valve tricúspide una guía paso a paso

Abstract Objective: The aim of this study was to present a valve-in-valve (ViV) case and a step-by-step guideline on how to perform this procedure. Methods: A 51-year-old female with a history of rheumatic heart disease and tricuspid valve replacement presented functional class deterioration, a transesophageal echocardiogram (TEE) revealed prosthetic dysfunction due to thrombosis; therefore, a valvular replacement with a 27 mm bioprosthesis (Carpentier-Edwards Perimount) was performed without complication. 3 years after the procedure, the patients presented functional class deterioration (NYHA-III) with tricuspid dysfunction by TEE and the heart team decided to perform a transcatheter tricuspid ViV replacement.

Resumen Objetivo: El objetivo de este artículo es presentar un caso clínico de un paciente en el cual se realizó el procedimiento valve-in-valve (ViV) en la válvula tricúspide junto con una guía de cómo llevar a cabo este procedimiento paso a paso. Metodología: Paciente femenino de 51 años de edad con antecedente de Cardiopatía Reumática presenta deterioro en clase funcional encontrándose por ecocardiografía transesofágica (ETE) disfunción de válvula protésica tricúspide secundario a trombosis, se realiza recambio valvular con prótesis biológica 27 mm (Carpentier Edwards Perimount) sin complicación. 3 años después, presenta deterioro de la clase funcional (NYHA-III) y se evidencia en ETE disfunción protésica tricúspide por lo cual se decide realizar un reemplazo ViV tricúspide transcatéter.

Efecto de la adición de lectina específica sobre la simbiosis Rhizobium leguminosarum--Phaseolus vulgaris / Effect of the addition of specific lectin on the symbiosis of Rhizobium leguminosarum and Phaseolus vulgaris

The effect of specific lectin addition on Rhizobium leguminosarum-Phaseolus vulgaris symbiosis characteristics was studied. Two alternatives were selected for comparison: a) P. vulgaris seedling roots treated with lectin were inoculated with R. leguminosarum and b) P. vulgaris seedling roots were inoculated with R. leguminosarum incubated with lectin for 3 h and 72 h. The following parameters were evaluated: number and dry weight of nodules and dry matter and nitrogen content of shoot. In lectin treatments, the weight of nodules (from 13 to 35), dry matter (from 6 to 18) and nitrogen content (from 5 to 28) increased significantly. The results suggest a stimulation in the formation of functional-nodules, specially in root (a) and Rhizobium (b) 72 h treatments. That is consistent with a model in which the lectin functions as an extracellular matrix component of the root interacting with roots and Rhizobium s.p. receptors.

La simbiosis Rhizobium-Prosopis en el Chaco Arido argentino / [The Rhizobium-Prosopis symbiosis in the Argentinian Chaco Arido]

Low productivity soils can be improved by incorporation of adapted legumes species able to increase the nitrogen fixation when associated to Rhizobium strains. Two fast-growing Rhizobium strains were isolated from nodules of Prosopis alba. Infectivity and effectivity of the strains were assessed under controlled conditions, measuring the following parameters: nodule number, dry weight, nitrogen percentage and fixed nitrogen. P. flexuosa strains showed high infective capacity (144 nodules/plant) but low effectivity (21.4 mg fixed nitrogen in 75 days). Although nodule number in P. alba was lower (23 nodules/plant) nitrogen fixation was higher (119.5 mg fixed nitrogen in 75 days) as compared with P. flexuosa. The isolated strains might be used as nitrogen donors in aride soils; they might be helpful to forestation of these ecosystems.

Efecto de la cobertura vegetal sobre la actividad biológica de un suelo del Chaco Arido / [Effect of the vegetative cover on the biological activity of the soil of Chaco Arido]

Vegetation plays a primal role in arid ecosystems, since it creates microclimate conditions that moderate the characteristics of the region whereby the rational use of vegetal resources is fundamental. Felling, clearing and overgrazing lead to decrease in organic contribution and stimulate soil compaction, causing an alteration of microbial activity, with losses in nutrient turnover. The global biological activity is a soil parameter easy to obtain and indicates the presence and diversity of soil life as well as substrate availability and is useful in order to characterize soil potential fertility. This work was carried out in Natural Forest Reserve Chancaní, Province of Córdoba (Argentina), which is representative of Argentine Dry Chaco. Dominant tree species are: Prosopis flexuosa and Aspidosperma quebracho blanco. The global biological activity (GBA) was measured along one year, under trees, under shrubs and in interspaces. Soil samples were taken monthly from plots with four management systems: 1) forest, ii) selective clearing (only dominant species remain), iii) bush (clearing invaded by Larrea sp) and iv) grazing (cleared area, neither trees nor shrubs). GBA was evaluated using the CO2 release method, after ten days of incubation. It is concluded that in the plots with grasses and under the trees GBA was higher than with other treatments. The lesser GBA was detected in bushes and interspaces. All differences were more prominent during extreme temperature months. No significant difference between both species of dominant trees was observed.