Endothelin receptor blockade prevents the rise in pulmonary vascular resistance after cardiopulmonary bypass in lambs with increased pulmonary blood flow

BACKGROUND: Children with increased pulmonary blood flow may experience morbidity as the result of increased pulmonary vascular resistance after operations in which cardiopulmonary bypass is used. Plasma levels of endothelin-1, a potent vasoactive substance implicated in pulmonary hypertension, are increased after cardiopulmonary bypass. OBJECTIVES: In a lamb model of increased pulmonary blood flow after in utero placement of an aortopulmonary shunt, we characterized the changes in pulmonary vascular resistance induced by hypothermic cardiopulmonary bypass and investigated the role of endothelin-1 and endothelin-A receptor activation in postbypass pulmonary hypertension. METHODS: In eleven 1-month-old lambs, the shunt was closed, and vascular pressures and blood flows were monitored. An infusion of a selective endothelin-A receptor blocker (PD 156707; 1.0 mg/kg/h) or drug vehicle (saline solution) was then begun 30 minutes before cardiopulmonary bypass and continued for 4 hours after bypass. The hemodynamic variables were monitored, and plasma endothelin-1 concentrations were determined before, during, and for 6 hours after cardiopulmonary bypass. RESULTS: After 90 minutes of hypothermic cardiopulmonary bypass, both pulmonary arterial pressure and pulmonary vascular resistance increased significantly in saline-treated lambs during the 6-hour study period (P <.05). In lambs pretreated with PD 156707, pulmonary arterial pressure and pulmonary vascular resistance decreased (P <. 05). After bypass, plasma endothelin-1 concentrations increased in all lambs; there was a positive correlation between postbypass pulmonary vascular resistance and plasma endothelin-1 concentrations (P <.05). CONCLUSIONS: This study suggests that endothelin-A receptor-induced pulmonary vasoconstriction mediates, in part, the rise in pulmonary vascular resistance after cardiopulmonary bypass. Endothelin-A receptor antagonists may decrease morbidity in children at risk for postbypass pulmonary hypertension. This potential therapy warrants further investigation.     

The effect of dietary Laminaria‐derived laminarin and fucoidan on nutrient digestibility,nitrogen utilisation,intestinal microflora and volatile fatty acid concentration in pigs

BACKGROUND: In experiment 1, 30 boars were assigned to one of five treatments (n = 6): T1, 0 g kg^?1 seaweed extract (SWE); T2, 0.7 g kg^?1 SWE; T3, 1.4 g kg^?1 SWE; T4, 2.8 g kg^?1 SWE and T5, 5.6 g kg^?1 SWE. The extract contained laminarin and fucoidan only and was extracted from Laminaria spp. In experiment 2, 28 boars were assigned, in a 2 × 2 factorial to one of four treatments (n = 7): T1, control; T2, control plus 300 mg laminarin; T3, control plus 240 mg fucoidan; T4, control plus 300 mg laminarin and 240 mg fucoidan kg^?1 diet. RESULTS: In experiment 1 there was a response to SWE on colonic Bifidobacterium spp. (P < 0.01 quadratic), Enterobacterium spp. (quadratic P < 0.05) and on caecal Enterobacterium spp. (quadratic P < 0.05). In experiment 2 there was an interaction (P < 0.05) between laminarin and fucoidan supplementation on Enterobacterium spp. in the proximal and distal colon. Pigs offered laminarin had reduced Enterobacterium spp. compared with pigs offered the control diet. However, the combination of laminarin and fucoidan had increased Enterobacterium spp. compared with alone. Pigs offered diets containing fucoidan had increased Lactobacilli spp. in the proximal colon (P < 0.05) and distal colon (P < 0.001) compared with non‐fucoidan diets. CONCLUSION: Overall, the reductions in intestinal Enterobacterium spp. and increases in Lactobacilli spp. obtained suggest that laminarin and fucoidan may provide a dietary means to improve gut health in pigs. Copyright © 2009 Society of Chemical Industry     

Effect of planting vertical/horizontal willow (Salix spp.) cuttings on establishment and yield

The conventional, commercial method of planting Short Rotation Coppice (SRC) willow is the use of a willow planter which delivers 20 cm hardwood cuttings vertically into the soil. On well prepared sites an establishment rate in excess of 90% is normal. Recently there has been interest in developing alternative planting protocols with the imminent launch of a ‘lay-flat planter’ which lays lengths of willow end to end at a depth of 8–10 cm. Small experimental plots were established in 2000 using two Salix spp. genotypes, ‘Olof’ and ‘V7534’ and three planting methods: conventional ‘cuttings’ (20 cm lengths planted vertically), ‘lay-flat’ rods (2–3 m lengths planted horizontally) and ‘billets’ (10 cm lengths planted horizontally). Two three-year harvests were taken in 2003/04 and 2006/07 when establishment, growth pattern and yield were assessed. While there were significant differences between the two genotypes, both responded in a similar way to the different planting protocols. Generally growth from billets was less than from either cuttings or lay-flat rods. The lay-flat system required almost three times more propagating material than either the cuttings or billets. Consequently for the system to be commercially viable significant savings must be made elsewhere, possibly through preparation of planting material, ground preparation or reducing planting costs.     

Simulation of sintering of model supported metal catalysts

During the past decade, the sintering of model supported metal catalysts, i.e. catalysts consisting of metal deposited on very thin and flat oxide films, has been intensively investigated by transmission electron microscopy. In the current paper, a mathematical model, based on an atomic migration mechanism, for the sintering of these catalysts is presented. The predictions of the model, based on Monte Carlo simulations, are in very good agreement with the experimental observations, i.e. phenomena such as ‘apparent’ particle migration, splitting and neck formation between particles are predicated by the model.     

An investigation into the synthesis of polycarbazole squaraine derivatives

The polycondensation of squaric acid with 1,2-(9-Ethylcarbazol-3-yl)ethene and N-ethyliminostilbene in polyphosphoric acid yielded insoluble polymers which included substituted phosphate groups on the phenyl rings. The presence of phosphorus in these polymers was identified using solid-state ³¹P NMR and EDAX techniques. Furthermore the phosphate groups were not ionic, hence no charge-balancing anions were present. Both polymers did not electrically conduct but exhibited dielectric breakdown values of 0.1 and 0.06 MV cm⁻¹ respectively. Received: 16 December 1996/Revised: 10 March 1997/Accepted: 10 March 1997     

Effect of sodium caseinate on the stability of cream liqueurs

The apparent viscosity of cream liqueurs prepared with different commercial sodium caseinates increased on storage at 45°C at rates and to extents that were dependent on which caseinate was used in the cream liqueur preparation. Increases in the apparent viscosity of fat free and fat free, micellar casein and whey protein free liqueurs indicated that differences in the caseinate s per se, rather than differences in interfacial absorption of the caseinates or the inclusion of micellar casein and whey proteins with the cream serum, caused the differences in increases in the apparent viscosity of cream liqueurs on storage at 45°C. No significant correlation was found between the calcium content of the caseinates and increases in the apparent viscosity of the liqueur systems on storage at 45°C. Addition of 2-mercaptoethanol to liqueurs after manufacture caused large increases in apparent viscosity, indicating that sulphydryl interactions may be important. Addition of NaCl to cream liqueurs resulted in an immediate increase in apparent viscosity, and on storage at 45°C for seven days, the liqueurs gelled, developed a high apparent viscosity or underwent phase separation, depending on which caseinate was used in the manufacture of the cream liqueur. Thus changes in the apparent viscosity of cream liqueurs on storage at 45°C are caseinate dependent and the results presented suggest that electrostatic and sulphydryl interactions may be involved in these changes.     

Course of functioning in adolescents 1 year after alcohol and other drug treatment.

Clinical course was studied in 131 male and female adolescents with current alcohol use disorder (AUD) at baseline (BL). Participants were classified into 4 groups according to their diagnosis and drinking pattern 1 year later. The 4 groups were compared with each other and with 37 community control participants. Results showed that over half of the clinical sample no longer had a current AUD at 1 year; about 64% were and 36% were not still drinking. BL discriminators of 1-year status were alcohol dependence, other drug use, and coping. All of the clinical groups tended to show improvement at 1 year in the main dependent variables, and the abstainers' level of drug use and coping were comparable with that of the community participants. These findings suggest that many adolescents improve in functioning during the 1 year after alcohol and drug treatment and that a stress and coping model is useful for studying clinical course of AUDs in adolescents. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Towards processible poly(pyrrol-2-ylsquaraines)

Summary In an attempt to produce a processible poly(pyrrol-2-ylsquaraine) by forming a copolymer of poly(pyrrol-2-ylsquaraine) with polymethylmethacrylate, two synthetic routes were utilised. The first included forming the polysquaraine and then polymerising the attached methacrylate groups to form the desired product and the second proceeded via the preformed methacrylate polymer, containing N-alkylpyrrole side chains, which was then condensed with squaric acid. Difficulties arose in the first route when the polysquaraine product was found to be insoluble, hence preventing any further polymerisation but partial solubility during the second procedure did allow bissquaraines to be formed and, as a consequence, the resultant product exhibited fluorescent properties. Yet the desired processible poly(pyrrol-2-ylsquaraine) was not achieved. Received: 30 October 1997/Revised version: 22 January 1998/Accepted: 23 January 1998     

Winning the global race for solar silicon

While there are numerous contestants in the race to produce low-cost solar silicon, the chemistries involved can be grouped into three categories: new Siemens-like processes, new approaches to reduction of silica, and upgrades of metallurgical-grade silicon. This review is focused on the thermo-chemistries being employed in the last two categories, with emphasis on removal of boron and phosphorous, as these elements are the two most difficult to remove from silicon by unidirectional solidification.