On Predation-Commensalism Processes as Models of Bi-stability and Constructive Role of Systemic Extinctions.

We propose a mathematical model for a class of predator-prey systems more complex than the usual one, involving a commensalism effect consisting in an influence of the predator on the sustainability of the prey. This effect induces interesting new features, including bi-stability (two attractors with disjoint attraction basins). The question of the possibility of reaching a certain attractor starting from initial conditions with a small population of predators, which presents an interest from the vewpoint of the onset of the predator in evolution, is addressed. We propose two possibilities: the classical one involving adapted conditions in the far past and a new (up to our knowledge) one using biodiversity, specifically the presence of another predator which operates as a starter, being displaced in the sequel.

In situ ergot alkaloid detection in three Balansia epichloe-infected grass species.

AIMS: The objectives of this work were to characterize molecularly the morphologically described endophyte Balansia epichloe symbiotic on three grass species, and to determine the in situ production of ergot alkaloids on these three symbiota. METHODS AND RESULTS: Balansia epichloe symbiotic with smut grass (Sporobolus poiretii), love grass (Eragrostis hirsuta) and lace grass (Eragrostis capillaries, a new host) were characterized using DNA barcoding. Laser ablation electro spray ionization (LAESI)-mass spectrometry was used to detect ergot alkaloids in situ for each symbiotum. CONCLUSIONS: The three morphologically described symbionts on the three host grasses were indicated as belonging to the species B. epichloe, DNA barcoding suggested they were related although a cryptic species was suggested. LAESI-mass spectrometry showed that ergot alkaloids were produced in vivo in two hosts but not the third although this same symbiotum was related to one of the ergot alkaloid producing symbiota as revealed by the DNA-barcoding procedure. SIGNIFICANCE AND IMPACT OF THE STUDY: These results established the accumulation of ergot alkaloids in pot culture by a morpho species although there were variations with each species of grass. Barcoding described divergence among species, but considering its limitation, the suggested existence of cryptic species among this morphospecies requires substantiation by studies that are more rigorous.

Structural instability and emergence of the biodiversity.

In the framework of population dynamics, we start from the logistic equation describing the evolution of one species with limited food supply. A split device allows us to consider the population as two sub-populations x and y evolving analogously. The dynamical system has a one-parameter family of equilibria which is structurally unstable. Then small perturbations of the system (describing functional or ethological differentiations between the sub-species) lead in general to a new system involving a fast and a slow dynamics with a finite number of equilibria. In simple situations where the differentiation is clearly either an advantage or an inconvenience for one of the subspecies, the stable equilibrium amounts to extinction of the disadvantaged subspecies (elementary Darwinism). Oppositely more complex differentiations (involving both advantages and inconveniences) often lead to stable equilibria with well-defined non zero proportions of the sub-populations (preservation of the biodiversity). Other examples are concerned with symbiosis-like differentiations, leading to preservation, whereas the opposite case (mutual nuisances) has an unstable equilibrium and lead to extinction of one or the other subspecies according to the initial conditions. The case of a scission into three subspecies is more rich in consequences. In certain cases, predator-prey relations lead to auto-organization phenomena with stable diversity-preserving diversity. Cases of instability are also possible, leading to orbits tending towards a poly-cycle.This implies some kind of pseudo-extinction: this amounts to "pseudo-periodic-like" orbits with "pseudo-periods" larger and larger, tending to infinity; each pseudo-period contains parts where one of the sub-populations practically vanish. Other non-linear perturbations lead to stable orbits.

Miopatía del enfermo crítico. Valoración neurofisiológica y biopsia muscular en 33 pacientes / Critical illness myopathy. Neurophysiological and muscular biopsy assessment in 33 patients

Introducción. Los enfermos críticos pueden desarrollar cuadros de debilidad importante en la Unidad de Cuidados Intensivos (UCI). Debido a la diversidad de criterios diagnósticos utilizados, existe desacuerdo sobre el origen miopático o neuropático de este cuadro. Objetivos. Describir las alteraciones neurofisiológicas de enfermos críticos, establecer grupos de pacientes según los datos electrofisiológicos de miopatía y determinar su correspondencia con los resultados de la biopsia muscular. Pacientes y métodos. Se estudiaron prospectivamente 33 pacientes en UCI con debilidad importante, mediante electromiografía, electroneurografía y biopsia muscular percutánea. En nueve casos se amplió el estudio con estimulación muscular directa y en 14 con estimulación repetitiva. Resultados. Aplicando criterios neurofisiológicos de miopatía, se describieron tres grupos de pacientes: miopatía definida (33%), miopatía probable (46%) y miopatía incierta (21%). En la biopsia muscular, las alteraciones miopáticas más intensas, con atrofia y necrosis fibrilar, vacuolas y alteraciones miosínicas y mitocondriales, se observaron en los grupos con miopatía definida y probable (26 casos). En 17 de ellos, los potenciales de acción muscular compuestos fueron de baja amplitud y los potenciales de acción del nervio sensitivo normales. Once pacientes mostraron polineuropatía axonal sensitivomotora, que en siete de ellos se asociaba con datos de miopatía. Conclusiones. En enfermos críticos con debilidad intensa, las alteraciones miopáticas en el estudio neurofisiológico son mucho más frecuentes que la afectación neuropática. En concordancia con estos hallazgos, las alteraciones miopáticas en la biopsia muscular son manifiestas y abundantes. Los datos histopatológicos y neurofisiológicos de esta serie no sustentan una hipotética neuropatía axonal motora pura (AU)

Introduction. Critical illness patients may show marked weakness acquired in the Intensive Care Unit (ICU). There are some disagreements about the myopathic versus neuropathic damage in this condition, presumably due to the lack of reliable diagnostic criteria. Aims. To report the neurophysiological findings in critical patients, to classify them in groups according to the electrophysiological data of myopathy, and to ascertain the rapport between the neurophysiological classification of myopathy and the muscle biopsy results. Patients and methods. A prospective assessment of 33 ICU patients with marked weakness by means of needle electromyography, electroneurography, and percutaneous muscle biopsy was carried out. Direct muscle stimulation was performed in 9 patients and repetitive nerve stimulation in 14 cases. Results. According to neurophysiological criteria, patients were classified in 3 groups: definite (33%), probable (46%), and uncertain (21%) myopathy. The most conspicuous myopathic pathological findings including fibrillar atrophy and necrosis, vacuoles, and myosin and mitochondrial anomalies, were observed in both, definite and probable groups (26 patients). In 17 of these cases, low amplitude of the compound motor action potentials and normal sensory nerve action potentials were found. Axonal sensory-motor neuropathy was present in 11 patients, concomitant with neurophysiological data of myopathy in 7 cases. Conclusions. Based on the neurophysiological criteria for the assessment and classification of acquired weakness in critically ill patients, myopathy is highly predominant over the neuropathic impairment. Histopathological findings are closely related to the electrophysiological diagnosis of myopathy. Neither neurophysiological nor pathological data support a hypothetic motor axonal neuropathy in this series (AU)

Valoración del potencial donante de órganos y tejidos en el seno de la pandemia por gripe A H1N1 / Evaluation of the potential organ and tissue donor within the pandemic of influenza H1N1

La pandemia de gripe A H1N1 supone un reto para el sistema sanitario, en general, y para las unidades de cuidados intensivos (UCI), en particular, por lo que tendrá sin duda repercusiones sobre el proceso de donación de órganos y tejidos. Por una parte, en un escenario posible de escasez de camas de la UCI y de dificultades para mantener la actividad quirúrgica a un ritmo normal, será necesario realizar un esfuerzo para crear las condiciones que aseguren el mantenimiento de la actividad trasplantadora, que no debe considerarse una actividad electiva. El otro problema relacionado con el impacto de la pandemia sobre la donación de órganos es la posibilidad de que un donante con gripe pueda transmitir la enfermedad vírica a los receptores. El presente trabajo tiene como objetivo clarificar esta cuestión, y revisar los datos existentes sobre la posibilidad de transmisión del virus de la gripe con los órganos o los tejidos trasplantados, las recomendaciones que se han dado en otros países y las que ha elaborado un grupo de trabajo ad hoc, constituido por representantes de la Organización Nacional de Trasplantes, del Ministerio de Sanidad y Política Social, de las coordinaciones autonómicas de trasplantes y de diversas sociedades científicas, incluida la Sociedad Española de Medicina Intensiva, Crítica y Unidades Coronarias (AU)

The pandemic strain of H1N1 supposes a challenge to the health care system in general and for Intensive Care Units (ICU) in particular. Therefore, it will undoubtedly have repercussions on the organ and tissue donation process. In a possible scenario of bed shortage in the ICU and difficulties in maintaining the surgical activity at a normal pace, a significant effort must be made to assure the maintenance of normal transplant activity, which should not be considered as an elective surgical procedure. Another problem related with the impact of the pandemic on the organ donation process is the possibility that a donor with influenza virus could transmit the disease to recipients. This work aims to clarify this issue, reviewing existing data on the potential transmission of influenza viruses with transplanted organs or tissue, the recommendations published in other countries and those developed in Spain by an ad hoc work group that is made up by representatives from the National Transplant Organization, the Ministry of Health and Social Policy, Regional Offices of Transplant Coordination, and various scientific societies, including SEMICYUC (AU)

[Evaluation of the potential organ and tissue donor within the pandemic of influenza H1N1]. / Valoración del potencial donante de órganos y tejidos en el seno de la pandemia por gripe A H1N1.

The pandemic strain of H1N1 supposes a challenge to the health care system in general and for Intensive Care Units (ICU) in particular. Therefore, it will undoubtedly have repercussions on the organ and tissue donation process. In a possible scenario of bed shortage in the ICU and difficulties in maintaining the surgical activity at a normal pace, a significant effort must be made to assure the maintenance of normal transplant activity, which should not be considered as an elective surgical procedure. Another problem related with the impact of the pandemic on the organ donation process is the possibility that a donor with influenza virus could transmit the disease to recipients. This work aims to clarify this issue, reviewing existing data on the potential transmission of influenza viruses with transplanted organs or tissue, the recommendations published in other countries and those developed in Spain by an ad hoc work group that is made up by representatives from the National Transplant Organization, the Ministry of Health and Social Policy, Regional Offices of Transplant Coordination, and various scientific societies, including SEMICYUC.

International shipping of fumonisins from maize extracts on C18 sorbent.

Fumonisins are mycotoxins found in maize. In developing countries, the resources required for analysis are often lacking, and the shipping of maize between countries can be difficult since the importation of plant materials requires permits/inspection to prevent the entry of pests that frequently infest maize. A simple, safe and legal method for shipping maize extracts to the USA was needed to conduct a survey of fumonisins in Central America. The objective was to develop a method for isolating and shipping maize extracts for fumonisin analysis so as to facilitate a survey of fumonisin exposure. The results indicate that fumonisins in acetonitrile:water extracts of maize can be isolated on C18 cartridges, held for at least 3 days at 22 degrees C and then an additional 4 days at 4 degrees C before elution and analysis with no losses. This method allows the importation and analysis of maize samples from foreign locations without complications from international safety concerns.

Recomendaciones de la 6.a Conferencia de Consenso de la SEMICYUC. Estado vegetativo persistente postanoxiaen el adulto / Recommendations of the VI Consensus Conference of the Spanish Society of Intensive Care Medicine and Coronary Units. Persistent postanoxic vegetative state in adults

No disponible

Generalised tuberculosis in a patient with acquired immunodeficiency syndrome.

We describe a heroin addict who presented with cellular immunodeficiency, generalised tuberculosis, and pneumonia caused by Pneumocystis carinii, and discuss the risk of these associations.