Evaluation of leukocyte dynamic in mouse retinal circulation with scanning laser ophthalmoloscopy (Video report)

http://bjo.bmj.com/content/suppl/2001/06/20/85.7.DC1 Leukocyte-endothelial cell interactions play an important role in the pathogenesis of various types of retinal vascular diseases, including diabetes, uveitis, and ischemic lesions. Over the last few years, several methods have been devised in which the scanning laser ophthalmoscope (SLO) is used to study leukocyte-endothelial interactions in vivo [1,2]. Previously we reported a noninvasive in vivo leukocyte tracking method using the SLO in rat. In this method, a nontoxic fluorescent agent (6-carboxyfluorescein diacetate, CFDA) was used to label leukocytes in vitro. Leukocyte velocities within the retinal and choroidal circulations were be quantified simultaneously [3]. None of the previous methods has been developed for imaging the murine fundus, mainly due to problems arising from the small size of the mouse eye. However, there are many advantages of using a murine model to study retinal vascular diseases such as enhanced genetic definition, increased range of reagents available for immunological studies and cost reduction. We have developed our SLO method such that we can track leukocytes in the mouse retinal and choroidal circulations.

Referral to an Extracorporeal Membrane Oxygenation Center and Mortality Among Patients With Severe 2009 Influenza A(H1N1)

Context Extracorporeal membrane oxygenation (ECMO) can support gas exchange in patients with severe acute respiratory distress syndrome (ARDS), but its role has remained controversial. ECMO was used to treat patients with ARDS during the 2009 influenza A(H1N1) pandemic.

Dynamics of the Indonesian seas circulation. Part II – The role of pressure head

The aim of this paper is to analyze the role of the pressure head, i.e., the difference of total pressure forces acting on the Indonesian seas waters from the western Pacific and the eastern Indian Ocean, in driving the Indonesian Throughflow (ITF) and in determining the total transport of the ITF. These questions have been discussed in the literature but no consensus has been reached. A regional model of the Indonesian seas circulation has been developed that properly resolves all major topographic features in the region. The results of model runs have been used to calculate all components of the overall momentum balance. The estimates disclose that the dynamical balance is primarily between the volume integrated Coriolis acceleration, pressure gradient and the area integral of local wind stress. It is shown that consideration of components of momentum balance in the direction of the outflow through the Indian Ocean port leads to the formulation of a diagnostic relation between total inflow transports due to the Mindanao and New Guinea Coastal Currents and the external pressure head, internal pressure head, bottom form stress, and area integrated wind stress. Based on this relation, it is concluded that the external pressure head is not the major driving force of the ITF, which is why there is no unique relation between the total transport of the ITF and the external pressure head. However, Wyrtki's suggestion to monitor the variability of the total transport of the ITF by measurement of the sea-surface-height difference between the western Pacific and the eastern Indian Ocean is validated.

Dynamics of the Indonesian seas circulation. Part I – The influence of bottom topography on temperature and salinity distributions

The influence of bottom topography on the distribution of temperature and salinity in the Indonesian seas region has been studied with a high-resolution model based on the Princeton Ocean Model. One of the distinctive properties of the model is an adequate reproduction of all major topographic features in the region by the model bottom relief. The three major routes of flow of Pacific water through the region have been identified. The western route follows the flow of North Pacific Water through the Sulawesi Sea, Makassar Strait, Flores Sea, and Banda Sea. This is the main branch of the Indonesian Throughflow. The eastern routes follow the flow of South Pacific water through the eastern Indonesian seas. This water enters the region either through the Halmahera Sea or by flowing to the north around Halmahera Island into the Morotai Basin and then into the Maluku Sea. A deep southward flow of South Pacific Water fills the Seram Sea below 1200 m through the Lifamatola Passage. As it enters the Seram Sea, this overflow turns eastward at depths greater than 2000 m, then upwells in the eastern part of the Seram Sea before returning westward at ~1500-2000 m. The flow continues westward across the Seram Sea, spreading to greater depths before entering the Banda Sea at the Buru-Mangole passage. It is this water that shapes the temperature and salinity of the deep Banda Sea. Topographic elevations break the Indonesian seas region down into separate basins. The difference in the distributions of potential temperature, ?, and salinity, S, in adjacent basins is primarily due to specific properties of advection of ? and S across a topographic rise. By and large, the topographic rise blocks deep flow between basins whereas water shallower than the depth of the rise is free to flow between basins. To understand this process, the structure of simulated fields of temperature and salinity has been analyzed. To identify a range of advected ? or S, special sections over the sills with isotherms or isohalines and isotachs of normal velocity have been considered. Following this approach the impact of various topographic rises on the distribution of ? and S has been identified. There are no substantial structural changes of potential temperature and salinity distributions between seasons, though values of some parameters of temperature and salinity distributions, e.g., magnitudes of maxima and minima, can change. It is shown that the main structure of the observed distributions of temperature and salinity is satisfactorily reproduced by the model throughout the entire domain.

CD11b+ bone marrow-derived monocytes are the major leukocyte subset responsible for retinal capillary leukostasis in experimental diabetes in mouse and express high levels of CCR5 in the circulation

We investigated the phenotype of cells involved in leukostasis in the early stages of streptozotocin-induced diabetes in mice by direct observation and by adoptive transfer of calcein-AM-labeled bone marrow-derived leukocytes from syngeneic mice. Retinal whole mounts, confocal microscopy, and flow cytometry ex vivo and scanning laser ophthalmoscopy in vivo were used. Leukostasis in vivo and ex vivo in retinal capillaries was increased after 2 weeks of diabetes (Hb A(1c), 14.2 ± 1.2) when either donor or recipient mice were diabetic. Maximum leukostasis occurred when both donor and recipient were diabetic. CD11b(+), but not Gr1(+), cells were preferentially entrapped in retinal vessels (fivefold increase compared with nondiabetic mice). In diabetic mice, circulating CD11b(+) cells expressed high levels of CCR5 (P = 0.04), whereas spleen (P = 0.0001) and retinal (P = 0.05) cells expressed increased levels of the fractalkine chemokine receptor. Rosuvastatin treatment prevented leukostasis when both recipient and donor were treated but not when donor mice only were treated. This effect was blocked by treatment with mevalonate. We conclude that leukostasis in early diabetic retinopathy involves activated CCR5(+)CD11b(+) myeloid cells (presumed monocytes). However, leukostasis also requires diabetes-induced changes in the endothelium, because statin therapy prevented leukostasis only when recipient mice were treated. The up-regulation of the HMG-CoA reductase pathway in the endothelium is the major metabolic dysregulation promoting leukostasis.

Elevated Circulation Levels of an Antiangiogenic SERPIN in Patients with Diabetic Microvascular Complications Impair Wound Healing through Suppression of Wnt Signaling

Wound healing, angiogenesis and hair follicle maintenance are often impaired in the skin of diabetic patients, but the pathogenesis has not been well understood. Here, we report that circulation levels of kallistatin, a member of the serine proteinase inhibitor (SERPIN) superfamily with anti-angiogenic activities, were elevated in Type 2 diabetic patients with diabetic vascular complications. To test the hypothesis that elevated kallistatin levels could contribute to a wound healing deficiency via inhibition of Wnt/β-catenin signaling, we generated kallistatin-transgenic (KS-TG) mice. KS-TG mice had reduced cutaneous hair follicle density, microvascular density, and panniculus adiposus layer thickness as well as altered skin microvascular hemodynamics and delayed cutaneous wound healing. Using Wnt reporter mice, our results showed that Wnt/β-catenin signaling is suppressed in dermal endothelium and hair follicles in KS-TG mice. Lithium, a known activator of β-catenin via inhibition of glycogen synthase kinase-3β, reversed the inhibition of Wnt/β-catenin signaling by kallistatin and rescued the wound healing deficiency in KS-TG mice. These observations suggest that elevated circulating anti-angiogenic serpins in diabetic patients may contribute to impaired wound healing through inhibition of Wnt/β-catenin signaling. Activation of Wnt/β-catenin signaling, at a level downstream of Wnt receptors, may ameliorate the wound healing deficiency in diabetic patients.Journal of Investigative Dermatology accepted article preview online, 24 January 2014. doi:10.1038/jid.2014.40.

Modeling the Western Iberian margin circulation: present and future

The purpose of this work is to carry out a comprehensive study on the Western Iberian Margin (WIM) circulation my means of numerical modeling, and to postulate what this circulation will be in the future. The adopted approach was the development of a regional ocean model configuration with high resolution, capable of reproducing the largeand small-scale dynamics of the coastal transition zone. Four numerical experiences were carried out according to these objectives: (1) a climatological run, in order to study the system’s seasonal behavior and its mean state; (2) a run forced with real winds and fluxes for period 2001-2011 in order to study the interannual variability of the system; (3) a run forced with mean fields from Global Climate Models (GCMs) for the present, in order to validate GCMs as adequate forcing for regional ocean modeling; (4) a similar run (3) for period 2071-2100, in order to assess possible consequences of a future climate scenario on the hydrography and dynamics of the WIM. Furthermore, two Lagrangian particle studies were carried out: one in order to trace the origin of the upwelled waters along the WIM; the other in order to portrait the patterns of larval dispersal, accumulation and connectivity. The numerical configuration proved to be adequate in the reproduction of the system’s mean state, seasonal characterization and an interannual variability study. There is prevalence of poleward flow at the slope, which coexists with the upwelling jet during summer, although there is evidence of its shifting offshore, and which is associated with the Mediterranean Water flow at deeper levels, suggesting a barotropic character. From the future climate scenario essay, the following conclusions were drawn: there is general warming and freshening of upper level waters; there is still poleward tendency, and despite the upwellingfavorable winds strengthening in summer the respective coastal band becomes more restricted in width and depth. In what concerns larval connectivity and dispersion along the WIM, diel vertical migration was observed to increase recruitment throughout the domain, and while smooth coastlines are better suppliers, there is higher accumulation where the topography is rougher.