ABSTRACT
La exposición a ambientes de hipoxia, está asociada con una disminución de la saturación arterial de oxígeno y el aumento de las presiones de la arteria pulmonar. El pre-condicionamiento isquémico de una extremidad (IPC Ischemic Preconditioning), es un procedimiento que estimula las vías vasoactiva e inflamatoria, que protegen los sistemas de órganos remotos, de daño isquémico. Para evaluar los efectos de IPC, en la saturación de oxígeno y presiones de la arteria pulmonar, a gran altura; fueron evaluados 12 voluntarios adultos sanos, en un ensayo aleatorio randomizado cruzado (randomized cross-over trial). El IPC fue realizado, utilizando un protocolo estandarizado. Se realizó IPC o placebo diariamente, durante 5 días previos al ascenso a gran altura. Todos los participantes fueron evaluados dos veces a 4243 m de altura (en condiciones de IPC y placebo, con un intervalo de 4 semanas, aleatorizados). La presión sistólica de la arteria pulmonar (PASP) a 4342 m fue significativamente menor en condiciones de IPC, que en condiciones de placebo (36±6.0 mmHg vs. 38.1±7.6 mmHg, respectivamente, p=0.0035). La saturación de oxígeno a 4342 m fue significativamente más elevada en IPC en comparación con placebo (80.3±8.7 por ciento vs. 75.3±9.6 por ciento, respectivamente, p-0.003). IPC como tratamiento profiláctico está asociado con una saturación de oxígeno mayor y atenuación del incremento normal de la presión de arteria pulmonar por hipoxia, seguida al ascenso a gran altura.
Subject(s)
Hypoxia , Heart FailureABSTRACT
Objective To explore the relationship between homestead distance to hospital and access to care and to estimate the sensitivity of hospital-based surveillance in Kilifi district; Kenya. Methods In 2002-2006; clinical information was obtained from all children admitted to Kilifi District Hospital and linked to demographic surveillance data. Travel times to the hospital were calculated using geographic information systems and regression models were constructed to examine the relationships between travel time; cause-specific hospitalization rates and probability of death in hospital. Access to care ratios relating hospitalization rates to community mortality rates were computed and used to estimate surveillance sensitivity. Findings The analysis included 7200 admissions (64 per 1000 child-years). Median pedestrian and vehicular travel times to hospital were 237 and 61 minutes; respectively. Hospitalization rates decreased by 21per hour of travel by foot and 28per half hour of travel by vehicle. Distance decay was steeper for meningitis than for pneumonia; for females than for males; and for areas where mothers had less education on average. Distance was positively associated with the probability of dying in hospital. Overall access to care ratios; which represent the probability that a child in need of hospitalization will have access to care at the hospital; were 51-58for pneumonia and 66-70for meningitis. Conclusion In this setting; hospital utilization rates decreased and the severity of cases admitted to hospital increased as distance between homestead and hospital increased. Access to hospital care for children living in remote areas was low; particularly for those with less severe conditions. Distance decay was attenuated by increased levels of maternal education. Hospital-based surveillance underestimated pneumonia and meningitis incidence by more than 45and 30; respectively
Subject(s)
Disease , Health Information Systems , Health Services Accessibility , KenyaABSTRACT
Mitochondrial gene rearrangements are much more frequent in vertebrates than initially thought. It has been suggested that the origin of light strand replication could have an important role in the process of gene rearrangements, but this hypothesis has never been tested before. We used amphibians to test the correlation between light-strand replication origin thermodynamic stability and the occurrence of gene rearrangements. The two variables were correlated in a non-phylogenetic approach, but when tested in a phylogenetically based comparative method the correlation was not significant, although species with unstable light-strand replication origins were much more likely to have undergone gene rearrangements. This indicates that within amphibians there are stable and unstable phylogenetic groups regarding mitochondrial gene order. The species analyzed showed variability in the thermodynamic stability of the secondary structure, in the length of its stem and loop, and several species did not present the 5-GCCGG-3 motif reported to be necessary for efficient mitochondrial DNA replication. Future studies should focus on the role of the light-strand replication origin in mitochondrial DNA replication and gene rearrangements mechanisms.