Reversal of dysfunction in postischemic stunned myocardium by epinephrine and postextrasystolic potentiation

After brief coronary occlusions, myocardium may become "stunned," exhibiting prolonged depression of function despite the absence of necrosis. Because of the accompanying decline in adenosine triphosphate and adenine nucleotide precursors, a deficiency of energy supply has been proposed as the basis for postischemic dysfunction. This study examined whether sufficient functional and metabolic reserve exists in stunned myocardium to sustain a prolonged, maximal inotropic response to epinephrine and postextrasystolic potentiation. In 11 open chest dogs, the left anterior descending coronary artery was occluded for 5 minutes, followed by 10 minutes of reflow, repeated 12 times, with a final 1 hour recovery period. Regional myocardial function was measured using pairs of ultrasonic dimension crystals implanted in ischemic and nonischemic zones.During repetitive reflows a progressive decrease in mean systolic segment shortening occurred: baseline 21.8%, 1st reflow 15.2%, 12th reflow 4.3%, 1 hour recovery 7.9%. Intravenous epinephrine, titrated to produce a maximal inotropic response, caused segment shortening to increase to 21.6% after 10 minutes and to 24.8 % after 1 hour of infusion, despite a 20 mm Hg increase in systolic pressure. The same dose of epinephrine given before ischemia increased segment shortening to 30.5%. In six of the dogs, postextrasystolic potentiation before ischemia increased segment shortening from 21.8 to 31.1%, and after 1 hour of recovery from ischemia, from 7.9 to 24.8%. Lesser increases in segment shortening were also seen in nonischemic segments.The results indicate that stunned myocardium possesses considerable functional reserve. Deficient energy stores are therefore not likely to be the basis for depressed function seen at rest in stunned myocardium

Emotional and Adrenocortical Responses of Infants to the Strange Situation: The Differential Function of Emotional Expression

The aim of the study was to investigate biobehavioural organisation in infants with different qualities of attachment. Quality of attachment (security and disorganisation), emotional expression, and adrenocortical stress reactivity were investigated in a sample of 106 infants observed during Ainsworth’s Strange Situation at the age of 12 months. In addition, behavioural inhibition was assessed from maternal reports. As expected, securely attached infants did not show an adrenocortical response. Regarding the traditionally defined insecurely attached groups, adrenocortical activation during the strange situation was found for the ambivalent group, but not for the avoidant one. Previous ndings of increased adrenocortical activity in disorganised infants could not be replicated. In line with previous ndings, adrenocortical activation was most prominent in insecure infants with high behavioural inhibition indicating the function of a secure attachment relationship as a social buffer against less adaptive temperamental dispositions. Additional analyses indicated that adrenocortical reactivity and behavioural distress were not based on common activation processes. Biobehavioural associations within the different attachment groups suggest that biobehavioural processes in securely attached infants may be different from those in insecurely attached and disorganised groups. Whereas a coping model may be applied to describe the biobehavioural organisation of secure infants, an arousal model explanation may be more appropriate for the other groups

How Sandcastles Fall

Capillary forces significantly affect the stability of sandpiles. We analyze the stability of sandpiles with such forces, and find that the critical angle is unchanged in the limit of an infinitely large system; however, this angle is increased for finite-sized systems. The failure occurs in the bulk of the sandpile rather than at the surface. This is related to a standard result in soil mechanics. The increase in the critical angle is determined by the surface roughness of the particles, and exhibits three regimes as a function of the added-fluid volume. Our theory is in qualitative agreement with the recent experimental results of Hornbaker et al., although not with the interpretation they make of these results.Comment: 4 pages, 2 figures, revte

Automated flow rate calculation based on digital analysis of flow convergence proximal to regurgitant orifice

AbstractObjectives. The purpose of the study was to develop and validate an automated method for calculating regurgitant flow rate using color Doppler echocardiography.Background. The proximal flow convergence method is a promising approach to quantitate valvular regurgitation noninvasively because it allows one to calculate regurgitant flow rate and regurgitant orifice area; however, defining the location of the regurgitant orifice is often difficult and can lead to significant error in the calculated flow rates. To overcome this problem we developed an automated algorithm to locate the orifice and calculate flow rate based on the digital Doppler velocity map.Methods. This algorithm compares the observed velocities with the anticipated relative velocities, cos ϑ/μt2. The orifice is localized as the point with maximal correlation between predicted and observed velocity, whereas flow rate is specified as the slope of the regression line. We validated this algorithm in an in vitro model for flow through circular orifices with planar surroundings and a porcine bioprosthesis.Results. For flow through circular orifices, flow rates calculated on individual Doppler maps and on an average of eight velocity maps showed excellent agreement with true flow, with r = 0.977 and ΔQ = −3.7 ± 15.8 cm3/s and r = 0.991 and ΔQ = −4.3 ± 8.5 cm3/s, respectively. Calculated flow rates through the bioprosthesis correlated well but underestimated true flow, with r = 0.97, ΔQ = −10.9 ± 12.5 cm3/s, suggesting flow convergence over an >2π. This systematic underestimation was corrected by assuming an effective convergence angle of 212 δ.Conclusions. This algorithm accurately locates the regurgitant orifice and calculates regurgitant flow rate for circular orifices with planar surroundings. Automated analysis of the proximal flow field is also applicable to more physiologic surfaces surrounding the regurgitant orifice; however, the convergence angle should be adjusted. This automated algorithm should make quantification of regurgitant flow rate and regurgitant orifice area more reproducible and readily available in clinical cardiology practice

67/09/27 Brief of American Civil Liberties Union, American Civil Liberties Union of Ohio, and New York Civil Liberties Union, Amici Curiae

The American Civil Liberties Union (ACLU), ACLU of New York and New York Civil Liberties Union\u27s Amici Curiae Brief arguing against the stop-and-frisk practice as seen in Terry v. Ohio and Chilton v. Ohio, Peters v. New York, and Sibron v. New York

67/09/27 Brief of American Civil Liberties Union, American Civil Liberties Union of Ohio, and New York Civil Liberties Union, Amici Curiae

The American Civil Liberties Union (ACLU), ACLU of New York and New York Civil Liberties Union\u27s Amici Curiae Brief arguing against the stop-and-frisk practice as seen in Terry v. Ohio and Chilton v. Ohio, Peters v. New York, and Sibron v. New York

The effect of national and constituency level expectations on tactical voting in the British general election of 2010

The 2010 elections in the United Kingdom provided voters with numerous and diverse opportunities to reason strategically. The Liberal Democrats (Lib Dems)-traditionally finishing a distant third in terms of seats in Parliament-vied with labour to be the principal competition to the Conservatives, who failed to win a majority of seats, creating a rare case of what the British call a hung parliament. These conditions varied across constituencies at the district level, and we exploit this variation to study the incidence of "tactical" voting. But the national outcome also presented strategic considerations for voters, and the conditions varied to some extent over the course of the campaign, giving voters interviewed at different times different sets of national considerations for tactical voting. This presents us with the opportunity to investigate how both local and national considerations may shape strategic reasoning among voters and relate to each other and to the final choices of voters on Election Day