Renal diseases that course with hypomagnesemia. Comments on a new hereditary hypomagnesemic tubulopathy

Renal diseases associated with hypomagnesemia are a complex and diverse group of tubulopathies caused by mutations in genes encoding proteins that are expressed in the thick ascending limb of the loop of Henle and in the distal convoluted tubule. In this paper, we review the initial description, the clinical expressiveness and etiology of four of the first hypomagnesemic tubulopathies described: type 3 Bartter and Gitelman diseases, Autosomal recessive hypomagnesemia with secondary hypocalcemia and Familial hypomagnesemia with hypercalciuria and nephrocalcinosis. The basic biochemical patterns observed in renal tubular hypomagnesemias and the modalities of transport and interaction that occur between the transporters involved in the reabsorption of magnesium in the distal convoluted tubule are described below. Finally, the recent report of a new renal disease with hypomagnesemia, type 2 hypomagnesemia with secondary hypocalcemia caused by reduced TRPM7 channel activity is described. Resumen: Las enfermedades renales que cursan con hipomagnesemia son un grupo complejo y variopinto de tubulopatías producidas por mutaciones en genes que codifican proteínas que se expresan en la rama gruesa ascendente del asa de Henle y en el túbulo contorneado distal. En el presente artículo revisamos la descripción inicial, la expresividad clínica y la etiología de cuatro de las primeras causas de tubulopatías hipomagnesémicas que se describieron: las enfermedades de Bartter tipo 3 y Gitelman, la hipomagnesemia con hipocalcemia secundaria autosómica recesiva y la hipomagnesemia familiar con hipercalciuria y nefrocalcinosis. A continuación, se describen los patrones bioquímicos básicos que se observan en las hipomagnesemias tubulares renales y las modalidades de transporte e interacción que concurren entre los transportadores implicados en la reabsorción de magnesio en el túbulo contorneado distal. Finalmente, se comunica la reciente descripción de una nueva tubulopatía hipomagnesémica, la hipomagnesemia con hipocalcemia secundaria tipo 2 causada por una reducción de la actividad del canal TRPM7

Biomass-dispersal trade-off and the functional meaning of species diversity

Production–diversity patterns lack a single explanation fully integrated in theoretical ecology. An ecological state equation has recently been found for ruderal vegetation. We studied 1649 plots from twenty-nine ecological assemblages and analyzed the relationship between diversity, biomass and dispersal looking for a pattern across these ecosystems. We found that high biomass and low dispersal values were significantly associated with high diversity plots under stationary conditions, and vice versa, involving a biomass-dispersal trade-off that is coherent with well-established ecological principles. Therefore, energy per plot, estimated as one half of the product of mean individual biomass and mean square dispersal multiplied by the number of individuals per plot, only reaches its maximum at intermediate levels of diversity. This explains the well-known humped relationship between production and diversity. We also explore why the rest of the diversity–production patterns can be explained starting from disruptions of this basic pattern. Simultaneously, the product of diversity, biomass and square dispersal is statistically equal to the ecological equivalent of the Boltzmann’s constant included in the ecological state equation that remains valid for all the assemblages explored due to scale variations in the value of the abovementioned constant. Biomass-dispersal trade-off resembles the principle of equipartition of energy from the kinetic theory of gases but in a characteristic way, because the alternative micro-associations of dispersal-biomass in function of species diversity are not randomly distributed as it happens with the combinations of molecular mass and velocity in a mixture of gases. Therefore, this distinctive ecological feature should be assumed as one of the main pro-functional gradients or thermodynamic constraints to avoid chaos and ecological degradation under stationary conditions. Hence, biomass-dispersal tradeoff explains production–diversity patterns and the ecological state equation in simultaneous agreement with conventional ecology and physics.Fundación Canaria Rafael ClavijoDIVERBO