Origin of congenital coronary arterio-ventricular fistulae from anomalous epicardial and myocardial development.

Coronary Artery Fistulae (CAFs) are cardiac congenital anomalies consisting of an abnormal communication of a coronary artery with either a cardiac chamber or another cardiac vessel. In humans, these congenital anomalies can lead to complications such as myocardial hypertrophy, endocarditis, heart dilatation, and failure. Unfortunately, despite their clinical relevance, the aetiology of CAFs remains unknown. In this work, we have used two different species (mouse and avian embryos) to experimentally model CAFs morphogenesis. Both conditional Itga4 (alpha 4 integrin) epicardial deletion in mice and cryocauterisation of chick embryonic hearts disrupted epicardial development and ventricular wall growth, two essential events in coronary embryogenesis. Our results suggest that myocardial discontinuities in the embryonic ventricular wall promote the early contact of the endocardium with epicardial-derived coronary progenitors at the cardiac surface, leading to ventricular endocardial extrusion, precocious differentiation of coronary smooth muscle cells, and the formation of pouch-like aberrant coronary-like structures in direct connection with the ventricular lumen. The structure of these CAF-like anomalies was compared with histopathological data from a human CAF. Our results provide relevant information for the early diagnosis of these congenital anomalies and the molecular mechanisms that regulate their embryogenesis.

Importance of mitochondrial P(O2) in maximal O2 transport and utilization: a theoretical analysis.

In previous calculations of how the O2 transport system limits .VO2(max), it was reasonably assumed that mitochondrial P(O2) (Pm(O2)) could be neglected (set to zero). However, in reality, Pm(O2) must exceed zero and the red cell to mitochondrion diffusion gradient may therefore be reduced, impairing diffusive transport of O2 and .VO2(max). Accordingly, we investigated the influence of Pm(O2) on these calculations by coupling previously used equations for O2 transport to one for mitochondrial respiration relating mitochondrial .VO2 to P(O2). This hyperbolic function, characterized by its P50 and V˙MAX, allowed Pm(O2) to become a model output (rather than set to zero as previously). Simulations using data from exercising normal subjects showed that at .VO2(max), Pm(O2) was usually <1mmHg, and that the effects on .VO2(max) were minimal. However, when O2 transport capacity exceeded mitochondrial V˙MAX, or if P50 were elevated,Pm(O2) often reached double digit values, thereby reducing the diffusion gradient and significantly decreasing .VO2(max).

Comparison of the prevalence and distribution of human papillomavirus infection and cervical lesions between urban and native habitants of an Amazonian region of Peru.

We made a study of the prevalence of human papillomavirus (HPV) and cervix lesions in an Amazonian Bora native population (Bn) and compared it with the prevalence in an urban population in Iquitos (Iq). We also examined the distribution of HPV types among abnormal cervical smears in the Iq population. Swabs and cytologies were collected from 472 females. DNA consensus PCR, followed by direct sequencing, were used to determinate the HPV types in the swabs. Cytologies were classified based on the lesion grade. HPV prevalence was 43.9% in Iq and 35.4% in Bn. Cervix lesion prevalence was 20.0% in Iq and 0.3% in Bn. The frequency of high-risk HPV types among HPV+ females was 71.9% in Iq and 56.3% in Bn. The frequencies of low-risk and undetermined risk HPV types were 19.3/6.3% (Iq/ Bn) and 12.3/37.5% (Iq/Bn), respectively. In lesIq (women seeking cytological services with a previous cervix lesion diagnosis) the prevalence of HPV, was 72.9%. The incidence of carcinoma and high-grade squamous intraepithelial cervix lesions in lesIq were 31.2 and 18.8%, respectively. The Bn population had a lower incidence of high-risk HPV and cervix lesions. The high-risk strain HPV16 was significantly more frequent in Iq compared with Bn. lesIq high-risk HPVs were more frequent in high-grade squamous intraepithelial lesions and carcinoma. High-risk HPV16 prevalence was significantly higher than the prevalence of the other high-risk HPVs, especially in the high-grade squamous intraepithelial lesions and carcinoma.