Microvascular regeneration in meshed skin transplants after severe burns

Function of the skin lymphatics as well as blood perfusion of a meshed transplant is crucial for the healing. The lymphatic regeneration and arterial perfusion of skin transplants after severe burns of the extremities had been studied in eight patients by microlymphography, laser doppler perfusion imaging and transcutaneous oxygen pressure measurements 1, 6 and 18 months after transplantation. One month after transplantation, only fragmented as well as many giant lymphatic skin vessels were present in the transplant. After 6 months a normal lymphatic network had developed in all grafts. The extension of the dye in the lymphatics decreased from 4.5 (0-16) at 1 month to 3.0 (1-6) mm after 18 months, indicating improved lymph drainage capacity. The permeability of the lymphatics in the graft was normal. After 1 month, median laser flux in the transplant was 155.6% (105-246%) of the normal skin but it normalised within 18 months. By contrast, transcutaneous oxygen measurement (TcPO(2)) increased from 44 (21-47) to 55 (50-76) mmHg. In meshed transplants used to cover severely burned skin morphological and functional normal lymphatics develop within 6 months and the initially increased laser flux due to inflammatory reaction normalises. Our results provide important insights into the healing process of skin transplants after burn

Evaluation of the meteorological forcing used for the Air Quality Model Evaluation International Initiative (AQMEII) air quality simulations

Copyright 2012 Elsevier B.V., All rights reserved.Accurate regional air pollution simulation relies strongly on the accuracy of the mesoscale meteorological simulation used to drive the air quality model. The framework of the Air Quality Model Evaluation International Initiative (AQMEII), which involved a large international community of modeling groups in Europe and North America, offered a unique opportunity to evaluate the skill of mesoscale meteorological models for two continents for the same period. More than 20 groups worldwide participated in AQMEII, using several meteorological and chemical transport models with different configurations. The evaluation has been performed over a full year (2006) for both continents. The focus for this particular evaluation was meteorological parameters relevant to air quality processes such as transport and mixing, chemistry, and surface fluxes. The unprecedented scale of the exercise (one year, two continents) allowed us to examine the general characteristics of meteorological models' skill and uncertainty. In particular, we found that there was a large variability between models or even model versions in predicting key parameters such as surface shortwave radiation. We also found several systematic model biases such as wind speed overestimations, particularly during stable conditions. We conclude that major challenges still remain in the simulation of meteorology, such as nighttime meteorology and cloud/radiation processes, for air quality simulation.Peer reviewedFinal Accepted Versio

Complex reinnervation pattern after unilateral renal denervation in rats.

Renal denervation (DNX) is a treatment for resistant arterial hypertension. Efferent sympathetic nerves regrow, but reinnervation by renal afferent nerves has only recently been shown in the renal pelvis of rats after unilateral DNX. We examined intrarenal perivascular afferent and sympathetic efferent nerves after unilateral surgical DNX. Tyrosine hydroxylase (TH), CGRP, and smooth muscle actin were identified in kidney sections from 12 Sprague-Dawley rats, to distinguish afferents, efferents, and vasculature. DNX kidneys and nondenervated kidneys were examined 1, 4, and 12 wk after DNX. Tissue levels of CGRP and norepinephrine (NE) were measured with ELISA and mass spectrometry, respectively. DNX decreased TH and CGRP labeling by 90% and 95%, respectively (P < 0.05) within 1 wk. After 12 wk TH and CGRP labeling returned to baseline with a shift toward afferent innervation (P < 0.05). Nondenervated kidneys showed a doubling of both labels within 12 wk (P < 0.05). CGRP content decreased by 72% [3.2 ± 0.3 vs. 0.9 ± 0.2 ng/gkidney; P < 0.05] and NA by 78% [1.1 ± 0.1 vs. 0.2 ± 0.1 pmol/mgkidney; P < 0.05] 1 wk after DNX. After 12 wk, CGRP, but not NE, content in DNX kidneys was fully recovered, with no changes in the nondenervated kidneys. The use of phenol in the DNX procedure did not influence this result. We found morphological reinnervation and transmitter recovery of afferents within 12 wk after DNX. Despite morphological evidence of sympathetic regrowth, NE content did not fully recover. These results suggest a long-term net surplus of afferent influence on the DNX kidney may be contributing to the blood pressure lowering effect of DNX