Vascular endothelial cell-specific phosphotyrosine phosphatase (VE-PTP) activity is required for blood vessel development

VE-PTP, a receptor-type phosphotyrosine phosphatase, associates with the tyrosine kinase receptor Tie-2 and VE-cadherin and enhances the adhesive function of the latter. Here, VE-PTP was found to be restricted to endothelial cells, with a preference for arterial endothelium. Mutant mice expressing a truncated, secreted form of VE-PTP lacking the cytoplasmic and transmembrane domains and the most membrane-proximal extracellular fibronectin type III repeat, showed severe vascular malformations causing lethality at 10 days of gestation. Although blood vessels were initially formed, the intraembryonic vascular system soon deteriorated. Blood vessels in the yolk sac developed into dramatically enlarged cavities. In explant cultures of mutant allantoides, endothelial cells were found next to vessel structures growing as cell layers. No signs for enhanced endothelial apoptosis or proliferation were observed. Thus, the activity of VE-PTP is not required for the initial formation of blood vessels, yet it is essential for their maintenance and remodeling.

[The incidence of Dicrocoelium dendriticum in Emmental]

A cross-sectional field study on the prevalence of Dicrocoelium dendriticum was performed in the Emmental. The study included 211 bovines, 170 equines, 20 ovines, 46 caprines and 23 rabbits (from 119 farms). In addition, laboratory routine diagnostic data obtained from 2.840 animals--all originating from the same area of investigation--were assessed in the same way. The infection extent concerning the different animal species were the following: bovines 46%, equines 12%, ovines 30%, caprines 48% and rabbits 9%. Univariate analyses of baseline epidemiological data identified no significant risk factors, with the exception of the type of stable used. Bovines kept in a modern free ranging stable had a significantly lower chance of infection with D. dendriticum than cattle in conventional tie stalls. The epidemiological data characterizing the area of investigation suggest the following procedure to reduce the problem of dicrocoeliosis: Pasturing animals of all ages should be regularly dewormed (e.g. every six week during pasture) using a compound effective against D. dendriticum. A treatment is especially indicated at the time after pasture in autumn or before housing the animals in winter. In spring, only animals having pastured the year before need to be treated prior to pasture in the new year. However, it is recommended to perform an economic analysis comparing costs of treatment versus putative costs of damage prior to the initiation of a strategic campaign: animal welfare aspects have to be considered. The laboratory routine diagnostic data showed infection extent similar to those of the cross-sectional study: bovines 60%, equines 24%, ovines 26%, caprines 31%, rabbits 32%. Atypical hosts such as dogs and cats exhibited low infection extent (3% and 1%, respectively), rather reflecting a gastro-intestinal passage of parasite eggs ingested by consumption of infected livers or by coprophagy of ruminant faeces.

Endothelial survival factors and spatial completion, but not pericyte coverage of retinal capillaries determine vessel plasticity

Pericyte loss and capillary regression are characteristic for incipient diabetic retinopathy. Pericyte recruitment is involved in vessel maturation, and ligand-receptor systems contributing to pericyte recruitment are survival factors for endothelial cells in pericyte-free in vitro systems. We studied pericyte recruitment in relation to the susceptibility toward hyperoxia-induced vascular remodeling using the pericyte reporter X-LacZ mouse and the mouse model of retinopathy of prematurity (ROP). Pericytes were found in close proximity to vessels, both during formation of the superficial and the deep capillary layers. When exposure of mice to the ROP was delayed by 24 h, i.e., after the deep retinal layer had formed [at postnatal (p) day 8], preretinal neovascularizations were substantially diminished at p18. Mice with a delayed ROP exposure had 50% reduced avascular zones. Formation of the deep capillary layers at p8 was associated with a combined up-regulation of angiopoietin-1 and PDGF-B, while VEGF was almost unchanged during the transition from a susceptible to a resistant capillary network. Inhibition of Tie-2 function either by soluble Tie-2 or by a sulindac analog, an inhibitor of Tie-2 phosphorylation, resensitized retinal vessels to neovascularizations due to a reduction of the deep capillary network. Inhibition of Tie-2 function had no effect on pericyte recruitment. Our data indicate that the final maturation of the retinal vasculature and its resistance to regressive signals such as hyperoxia depend on the completion of the multilayer structure, in particular the deep capillary layers, and are independent of the coverage by pericytes.

Angiopoietin-1 induces sprouting angiogenesis in vitro

Sprouting of new capillaries from pre-existing blood vessels is a hallmark of angiogenesis during embryonic development and solid tumor growth [1]. In addition to the vascular endothelial growth factor (VEGF) and its receptors, the Tie receptors and their newly identified ligands, the angiopoietins, have been implicated in the control of blood vessel formation [2,3]. Although 'knockouts' of the gene encoding the Tie2 receptor, or its activating ligand angiopoietin-1 (Ang1), result in embryonic lethality in mice due to an absence of remodeling and sprouting of blood vessels [4,5], biological activity in vitro has not yet been described for this receptor-ligand system. In an assay in which a monolayer of endothelial cells were cultured on microcarrier beads and embedded in three-dimensional fibrin gels, recombinant Ang1 (0.5-10 nM) induced the formation of capillary sprouts in a dose-dependent manner that was completely inhibited by soluble Tie2 receptor extracellular domains. In contrast with VEGF, which also induced sprouting of capillaries, Ang1 was only very weakly mitogenic for endothelial cells. Suboptimal concentrations of VEGF and Ang1 acted synergistically to induce sprout formation. Thus, the biological activity of Ang1 in vitro is consistent with the specific phenotype of mice deficient in Tie2 or Ang1. The data suggest that, like in other developmental systems, blood vessel formation requires a hierarchy of master-control genes in which VEGF and angiopoietins, along with their receptors, are amongst the most important regulators.

A randomized controlled 1-year study of daily deferiprone plus twice weekly desferrioxamine compared with daily deferiprone monotherapy in patients with thalassemia major

BACKGROUND AND OBJECTIVES: The aim of this prospective, randomized, 1-year study was to compare the efficacy and safety of oral deferiprone (DFP) with those of combinations of parenteral desferrioxamine (DFO) with oral DFP. DESIGN AND METHODS: A total of 24 patients with thalassemia major were randomized to receive one of the following two treatments; DFP given at a daily dose of 75 mg/kg in combination with DFO (40-50 mg/kg twice weekly) (n=12) or as single agent (n=12). In addition, 12 patients treated with 40-50 mg/kg DFO 5 days weekly were included as a reference group without randomization. Changes in liver iron concentration (LIC) and serum ferritin (SF) were assessed; total iron excretion (TIE), urinary iron excretion (UIE) and iron balance were calculated. Cardiac function and toxicity were also examined. DESIGN AND METHODS: SF and LIC were significantly reduced after 1 year of combination therapy (p=0.01 and 0.07, respectively). A decrease of LIC was observed in all but one patient (87.5%) following the combination therapy but in only 42% of patients treated with DFP monotherapy. In the DFO reference group, a statistically significant decrease in LIC (p=0.01) associated with a substantial decrease in SF (p=0.08) was observed after 1 year. The combination regimen resulted in greater TIE compared to DFP monotherapy (p=0.08) and was the regimen associated with the highest iron balance compared to DFP monotherapy (p=0.04) or standard DFO treatment (p=0.006). INTERPRETATIONS AND CONCLUSIONS: The addition of subcutaneous DFO twice weekly to oral DFP 75 mg/kg is a highly efficacious and safe chelation therapy providing superior chelation activity to that of DFP and likely has an efficacy profile comparable to that of standard DFO.

Inducible endothelial cell-specific gene expression in transgenic mouse embryos and adult mice

Utilizing both the TET-OFF and TET-ON systems in combination with transcriptional control elements of the Tie-2 gene, we have established a series of transgenic activator and responder mice for TET-regulated endothelial cell-specific transgene expression in double transgenic mouse embryos and in adult mice. TET-regulated expression of LacZ reporter genes could be achieved in virtually all endothelia in mid gestation stage mouse embryos. In contrast in adult mice, using the very same Tie-2 tTA activator mouse strain, we observed striking differences of TET-induced gene expression from various inducible expression constructs in different vascular beds. Non-endothelial expression was never detected. The prominent differences in completeness of TET-induced endothelial expression highlight the still underestimated critical role of the responder mouse lines for uniform TET-induced gene expression in heterogeneous cell populations such as endothelial cells. Interestingly, in double transgenic mice inducibly expressing several different adhesion molecules, no adverse effects were observed even though these proteins were robustly expressed on endothelial cells in adult tissues. These transgenic model systems provide versatile tools for the TET-regulated manipulation of endothelial cell-specific gene expression in the entire embryonic vasculature and distinct vascular beds in adult mice.

Online distribution management framework by incorporating wind generation

In distribution system operations, dispatchers at control center closely monitor system operating limits to ensure system reliability and adequacy. This reliability is partly due to the provision of remote controllable tie and sectionalizing switches. While the stochastic nature of wind generation can impact the level of wind energy penetration in the network, an estimate of the output from wind on hourly basis can be extremely useful. Under any operating conditions, the switching actions require human intervention and can be an extremely stressful task. Currently, handling a set of switching combinations with the uncertainty of distributed wind generation as part of the decision variables has been nonexistent. This thesis proposes a three-fold online management framework: (1) prediction of wind speed, (2) estimation of wind generation capacity, and (3) enumeration of feasible switching combinations. The proposed methodology is evaluated on 29-node test system with 8 remote controllable switches and two wind farms of 18MW and 9MW nameplate capacities respectively for generating the sequence of system reconfiguration states during normal and emergency conditions.

Comparative study of anchorage strengths of epoxy coated hooked bars

Hooked reinforcing bars (rebar) are used frequently to carry the tension forces developed in beams and transferred to columns. Research into epoxy coated hooked bars has only been minimally performed and no research has been carried out incorporating the coating process found in ASTM A934. This research program compares hooked rebar that are uncoated, coated by ASTM A775, and coated by ASTM A934. In total, forty-two full size beam-column specimens were created, instrumented and tested to failure. The program was carried out in three phases. The first phase was used to refine the test setup and procedures. Phase two explored the spacing of column ties within the joint region. Phase three explored the three coating types found above. Each specimen included two hooked rebar which were loaded and measured independently for relative rebar slip. The load and displacement of the hooked rebar were analyzed, focusing on behavior at the levels of 30 ksi, 42 ksi and 60 ksi of rebar stress. Statistical and general comparisons were made using the coating types, tie spacing, and rebar stress level. Many of the parameters composing the rebar and concrete were also tested to characterize the components and specimens. All rebar tested met ASTM standards for tensile strength, but the newer ASTM A934 method seemed to produce slightly lower yield strengths. The A934 method also produced coating thicknesses that were very inconsistent and were higher than ASTM maximum limits in many locations. Continuity of coating surfaces was found to be less than 100% for both A775 and A934 rebar, but for different reasons. The many comparisons made did not always produce clear conclusions. The data suggests that the ACI Code (318-05) parameter of 1.2 for including epoxy coating on hooked rebar may need to be raised, possibly to 2.5, but more testing needs to be performed before such a large value change is set forth. This is particularly important as variables were identified which may have a larger influence on rebar capacity than the Development Length, of which the current 1.2 factor modifies. Many suggestions for future work are included throughout the thesis to help guide other researchers in carrying out successful and productive programs which will further the highly understudied topic of hooked rebar.

VEGF-A stimulates ADAM17-dependent shedding of VEGFR2 and crosstalk between VEGFR2 and ERK signaling

Vascular endothelial growth factor (VEGF)-A and the VEGF receptors are critical for regulating angiogenesis during development and homeostasis and in pathological conditions, such as cancer and proliferative retinopathies. Most effects of VEGF-A are mediated by the VEGFR2 and its coreceptor, neuropilin (NRP)-1. Here, we show that VEGFR2 is shed from cells by the metalloprotease disintegrin ADAM17, whereas NRP-1 is released by ADAM10. VEGF-A enhances VEGFR2 shedding by ADAM17 but not shedding of NRP-1 by ADAM10. VEGF-A activates ADAM17 via the extracellular signal-regulated kinase (ERK) and mitogen-activated protein kinase pathways, thereby also triggering shedding of other ADAM17 substrates, including tumor necrosis factor alpha, transforming growth factor alpha, heparin-binding epidermal growth factor-like growth factor, and Tie-2. Interestingly, an ADAM17-selective inhibitor shortens the duration of VEGF-A-stimulated ERK phosphorylation in human umbilical vein endothelial cells, providing evidence for an ADAM17-dependent crosstalk between the VEGFR2 and ERK signaling. Targeting the sheddases of VEGFR2 or NRP-1 might offer new opportunities to modulate VEGF-A signaling, an already-established target for treatment of pathological neovascularization.

Pericyte migration: a novel mechanism of pericyte loss in experimental diabetic retinopathy

OBJECTIVE: The mechanism underlying pericyte loss during incipient diabetic retinopathy remains controversial. Hyperglycemia induces angiopoietin-2 (Ang-2) transcription, which modulates capillary pericyte coverage. In this study, we assessed loss of pericyte subgroups and the contribution of Ang-2 to pericyte migration. RESEARCH DESIGN AND METHODS: Numbers of total pericytes and their subgroups were quantified in retinal digest preparations of spontaneous diabetic XLacZ mice. Pericytes were divided into subgroups according to their localization, their position relative to adjacent endothelial cells, and the expression of LacZ. The contribution of Ang-2 to pericyte migration was assessed in Ang-2 overexpressing (mOpsinhAng2) and deficient (Ang2LacZ) mice. RESULTS: Pericyte numbers were reduced by 16% (P < 0.01) in XLacZ mice after 6 months of diabetes. Reduction of pericytes was restricted to pericytes on straight capillaries (relative reduction 27%, P < 0.05) and was predominantly observed in LacZ-positive pericytes (-20%, P < 0.01). Hyperglycemia increased the numbers of migrating pericytes (69%; P < 0.05), of which the relative increase due to diabetes was exclusively in LacZ-negative pericytes, indicating reduced adherence to the capillaries (176%; P < 0.01). Overexpression of Ang-2 in nondiabetic retinas mimicked diabetic pericyte migration of wild-type animals (78%; P < 0.01). Ang-2 deficient mice completely lacked hyperglycemia-induced increase in pericyte migration compared with wild-type littermates. CONCLUSIONS: Diabetic pericyte loss is the result of pericyte migration, and this process is modulated by the Ang-Tie system.

Some Leaching Characteristics of the Butte Rhodochrosite

With the increasing importance of manganese in the metallurgical fields of today and tomorrow, ex­tensive work along the lines of its successful ex­ploitation has been accomplished by many investiga­tors. Since tie current world situation has shut off most of our supply of high-grade manganese ores from foreign sources, the low-grade domestic deposits have entered the fields of investigation very rapidly.

Geological Report of Conrow Wood Creek Area 8 Miles N.E. of Whitehall, Montana

Plane table and pacing methods were used in the mapping of the individual areas, but an automobile traverse was used to tie the independent areas into a composite group that would be useful for the entire zone. All land marks, section corners, roads, fence lines, drainage, and geologic features were plotted in the field and later transferred to a master map.

Ankyloglossia: facts and myths in diagnosis and treatment

BACKGROUND: The objective of this study was to systematically review the diagnostic criteria, indications, and need for treatment of ankyloglossia (tongue-tie), as well as the various treatment options for patients in different age groups. METHODS: The MEDLINE databases and the Cochrane Library were searched according to well-defined criteria, resulting in 64 included articles. The evidence regarding the classifications of tongue-tie, epidemiologic data, inheritance, breastfeeding problems, impaired tongue mobility, speech disorders, malocclusion, gingival recessions, therapy, and complications due to surgery was analyzed in detail. RESULTS: Different classifications for ankyloglossia have been proposed but not uniformly accepted. Breastfeeding problems in neonates could be associated with a tongue-tie, but not enough controlled trials have been performed to identify an ideal treatment option. In children and adults with ankyloglossia, limitations in tongue mobility are present, but the individual degree of discomfort, as well as the severity of an associated speech problem, are subjective and difficult to categorize. There is no evidence supporting the development of gingival recessions because of ankyloglossia. Frenotomy, frenectomy, and frenuloplasty are the main surgical treatment options to release/remove an ankyloglossia. Because of the limited evidence available, no specific surgical method can be favored. CONCLUSIONS: The lack of an accepted definition and classification of ankyloglossia makes comparisons between studies almost impossible. Because almost no controlled prospective trials for surgical interventions in patients with tongue-ties are present in the literature, no conclusive suggestions regarding the method of choice can be made. It also remains controversial which tongue-ties need to be surgically removed and which can be left to observation.

Were last glacial climate events simultaneous between Greenland and western Europe?

During the last glacial period, several large abrupt climate fluctuations took place on the Greenland ice cap and elsewhere. Often these Dansgaard/Oeschger events are assumed to have been synchronous, and then used as tie-points to link chronologies between the proxy archives. However, if temporally separate events are lumped into one illusionary event, climatic interpretations of the tuned events will obviously be flawed. Here, we compare Dansgaard/Oeschger-type events in a well-dated record from south-eastern France with those in Greenland ice cores. Instead of assuming simultaneous climate events between both archives, we keep their age models independent. Even these well-dated archives possess large chronological uncertainties, that prevent us from inferring synchronous climate events at decadal to multi-centennial time scales. If possible, tuning of proxy archives should be avoided.

Approaching Migrant Youth Marginalization through the Capabilities Approach: Methodological Proposals

Adopting the capabilities approach and the terminology that has been respectively developed, we could assume that Amartya Sen’s “capabilities” consist in the actual living that people manage to achieve (“functionings”) as a result of actual free will. Sen’s freedom does not “only [depend on the] mere degree of the presence or absence of coercion or interference (from others)” (Otto and Ziegler 2006) but also on “the range of options a person has in deciding what kind of life to lead” (Dreze and Sen 1995, 10). In his book, Identity and Violence, Sen, without explicitly connecting the capabilities approach with his views on “genuine multiculturalis” (Sen 2007), in fact, introduces this extended conception of freedom in the way we examine identity matters. Since freedom becomes perceptible as the range of options a person has, concerning the kind of life he wishes to live, cultural freedom can be defined through the concept of the multiplicity of belonging. In other words, cultural freedom constitutes itself a capability, which is realized when nothing and no one, not even myself, can tie me down to a kind of cultural rigidity that tends to exclude and marginalize me. This latent connection of “capabilities” with “multiple identities” (Sen 2007) challenges us to search for the contribution Sen’s approach could have in the understanding and confrontation of issues concerning migrants, away from theoretical patterns that overemphasize the cultural otherness as an impediment to inclusion. Besides, Sen himself, without of course focusing exclusively on migrants, has already approached the matter of social exclusion with terms of his capabilities approach (Sen 2000).