Beta-blocker therapy of severe congestive heart failure in infants with left to right shunts

We report on the clinical and neurohumoral effects of adding low-dose propranolol to conventional therapy with digoxin and diuretics in 6 infants with severe congestive heart failure due to large left-to-right shunts. A significant decrease in heart failure scores and a decrease of the highly activated renin-angiotensin-1 aldosterone system by approximately 70% strongly suggests a beneficial effect of this new therapeutic approach.

A qualitative field method for monitoring pesticides in the edge-of-field runoff

A field method is described, which allows the qualitative estimation of pesticide contamination in the edge-of-field runoff. The method employs cheap and easy-to-use runoff sampling bottles, which were installed in an agricultural stream catchment over a period of three growing seasons. During this time 18 runoff events were detected, in nine of which insecticide contamination was measured (maximum concentrations: lindane 0.7 microgram l-1 and 12.7 micrograms kg-1, parathion 20 micrograms l-1 and 728 micrograms kg-1, fenvalerate 18.4 micrograms l-1 and 924 micrograms kg-1). These insecticides were detected mainly as particle-bound chemicals. On about 80% of the occasions the presence or absence of runoff measured in the field was in agreement with a simulation of runoff presence or absence using the runoff model KINEROS.

K(ATP)-channel activation: effects on myocardial recovery from ischaemia and role in the cardioprotective response to adenosine A1-receptor stimulation

1. Optimization of myocardial energy substrate metabolism improves the recovery of mechanical function of the post-ischaemic heart. This study investigated the role of K(ATP)-channels in the regulation of the metabolic and mechanical function of the aerobic and post-ischaemic heart by measuring the effects of the selective K(ATP)-channel activator, cromakalim, and the effects of the K(ATP)-channel antagonist, glibenclamide, in rat fatty acid perfused, working hearts in vitro. The role of K(ATP) channels in the cardioprotective actions of the adenosine A1-receptor agonist, N6-cyclohexyladenosine (CHA) was also investigated. 2. Myocardial glucose metabolism, mechanical function and efficiency were measured simultaneously in hearts perfused with modified Krebs-Henseleit solution containing 2.5 mM Ca2+, 11 mM glucose, 1.2 mM palmitate and 100 mu l(-1) insulin, and paced at 300 beats min(-1). Rates of glycolysis and glucose oxidation were measured from the quantitative production of 3H20 and 14CO2, respectively, from [5-3H/ U-14C]-glucose. 3. In hearts perfused under aerobic conditions, cromakalim (10 microM), CHA (0.5 microM) or glibenclamide (30 microM) had no effect on mechanical function. Cromakalim did not affect glycolysis or glucose oxidation, whereas glibenclamide significantly increased rates of glycolysis and proton production. CHA significantly reduced rates of glycolysis and proton production but had no effect on glucose oxidation. Glibenclamide did not alter CHA-induced inhibition of glycolysis and proton production. 4. In hearts reperfused for 30 min following 30 min of ischaemia, left ventricular minute work (LV work) recovered to 24% of aerobic baseline values. Cromakalim (10 microM), administered 5 min before ischaemia, had no significant effect on mechanical recovery or glucose metabolism. CHA (0.5 microM) significantly increased the recovery of LV work to 67% of aerobic baseline values and also significantly inhibited rates of glycolysis and proton production. Glibenclamide (30 microM) significantly depressed the recovery of mechanical function to < 1% of aerobic baseline values and stimulated glycolysis and proton production. 5. Despite the deleterious actions of glibenclamide per se in post-ischaemic hearts, the beneficial effects of CHA (0.5 microM) on the recovery of mechanical function and proton production were not affected by glibenclamide. 6. The data indicate that the cardioprotective mechanism of adenosine A1-receptor stimulation does not involve the activation of K(ATP)-channels. Furthermore, in rat fatty acid perfused, working hearts, stimulation of K(ATP)-channels is not cardioprotective and has no significant effects on myocardial glucose metabolism.

Research on physiological and physical concomitants of caregiving: where do we go from here?

This article discusses the current state of research on the physiological and physical concomitants of caregiving. We offer recommendations about theoretical, empirical, and treatment issues that researchers should consider in future investigations. Important theoretical issues include specifying acute and chronic stress in caregiving research. Empirical issues include sample selection, home versus clinic assessments, the use of experimental probes, moderating and mediating variables, and measurement issues (problems with self-report of health, medical records, physical exams, and lab assessments). Finally, we note that investigators should use this newfound knowledge to target interventions to specific subsets of vulnerable caregivers. In this way, basic research into caregiving, as a model of chronic human stress, can provide more focused approaches to benefit both caregivers and patients.

Health effects of caregiving: the caregiver health effects study: an ancillary study of the Cardiovascular Health Study

We propose that two related sources of variability in studies of caregiving health effects contribute to an inconsistent pattern of findings: the sampling strategy used and the definition of what constitutes caregiving. Samples are often recruited through self-referral and are typically comprised of caregivers experiencing considerable distress. In this study, we examine the health effects of caregiving in large population-based samples of spousal caregivers and controls using a wide array of objective and self-report physical and mental health outcome measures. By applying different definitions of caregiving, we show that the magnitude of health effects attributable to caregiving can vary substantially, with the largest negative health effects observed among caregivers who characterize themselves as being strained. From an epidemiological perspective, our data show that approximately 80% of persons living with a spouse with a disability provide care to their spouse, but only half of care providers report mental or physical strain associated with caregiving.

Activity restriction and prior relationship history as contributors to mental health outcomes among middle-aged and older spousal caregivers

In a sample of cancer patients (n = 75) and spousal caregivers (24 men and 51 women), restriction in caregiver routine activities mediated associations between caregiving stress (patient symptom severity) and caregiver depressed affect and resentment. Moreover, the antecedents and affective consequences of caregiver activity restriction were consistent with the theory of communal relationships (e.g., M. S. Clark & J. Mills, 1979, 1993). If a relationship had been communal in the past (i.e., characterized by mutual concern for and responsiveness to one another's needs), activity restriction was predicted by intimacy and affectional loss (rather than by the severity of patient symptoms) and in turn predicted caregiver depressed affect. Among caregivers in less communal relationships, activity restriction was predicted by severity of patient symptoms (rather than by intimacy and affectional loss) and in turn predicted resentment of care recipients and the caregiving role.

Caregiving from the recipient's perspective: negative reactions to being helped

This study investigated predictors of negative reactions to assistance provided to a physically disabled spouse (n = 276, M age: 76.6 years) and the consequences that negative reactions may have for the mental health of the care recipient. Nearly 40% of recipients reported some emotional distress in response to help they received. Fatalistic attitudes, perceived control, and lower self-esteem predicted greater helping distress, whereas lower self-esteem, fatalistic beliefs, and marital conflict were especially likely to lead to helping distress for those who received higher levels of assistance. Helping distress was also found to predict depression as much as 1 year later, suggesting that there may be long-term consequences of negative reactions to assistance. These findings have important implications for the study of caregiving and the relationship between physical impairment and depression.

Intrinsic ANG II type 1 receptor stimulation contributes to recovery of postischemic mechanical function

To determine whether intrinsic angiotensin II (ANG II) type 1 receptor (AT1-R) stimulation modulates recovery of postischemic mechanical function, we studied the effects of selective AT1-R blockade with losartan on proton production from glucose metabolism and recovery of function in isolated working rat hearts perfused with Krebs-Henseleit buffer containing palmitate, glucose, and insulin. Aerobic perfusion (50 min) was followed by global, no-flow ischemia (30 min) and reperfusion (30 min) in the presence (n = 10) or absence (n = 14) of losartan (1 mumol/l) or the cardioprotective adenosine A1 receptor agonist N6-cyclohexyladenosine (CHA, 0.5 mumol/l, n = 11). During reperfusion in untreated hearts (controls), left ventricular (LV) minute work partially recovered to 38% of aerobic baseline, whereas proton production increased to 155%. Compared with controls, CHA improved recovery of LV work to 79% and reduced proton production to 44%. Losartan depressed recovery of LV work to 0% without altering proton production. However, exogenous ANG II (1-100 nmol/l) in combination with losartan restored recovery of LV work during reperfusion in a concentration-dependent manner, suggesting that postischemic recovery of function depends on intrinsic AT1-R stimulation.

The role of neuroticism and mastery in spouse caregivers' assessment of and response to a contextual stressor

Data from more than 300 spousal caregivers and their care recipients were analyzed to demonstrate the effects of caregivers' personality attributes--neuroticism and mastery--on their assessment of a contextual stressor (the care recipient's behavioral and functional impairment) and on their experience of distress associated with that stressor. Caregivers who were high in neuroticism and/or low in mastery reported higher levels of behavioral and functional impairment in their disabled spouse and experienced more strain and depressive symptoms associated with caregiving relative to caregivers with lower neuroticism or higher mastery scores. We further showed that the widely reported association between caregiver-assessed impairment of the care recipient and caregiver outcomes can in part be explained by caregivers' personality attributes, such as neuroticism and mastery. Our findings that caregivers' personality variables are related to their assessment of a given objective stressor and their response to a given level of stress have implications for interventions targeting caregivers and for the use of caregivers as proxy informants.

Translocation of phosducin in living neuroblastoma x glioma hybrid cells (NG 108-15) monitored by red-shifted green fluorescent protein

Activation of G protein-coupled receptors triggers translocation of certain proteins from cytoplasm to cell membrane located targets. One of these cytosolic proteins is phosducin (Phd) which has been described to compete with G protein-coupled receptor kinases for Gbetagamma dimers attached to the cell membrane, thereby attenuating desensitization of activated receptors. These features of protein redistribution prompted us to examine whether stimulation of membrane associated E-prostaglandin receptors coupled to Gs causes Phd to migrate towards the plasma membrane. We made use of enhanced green fluorescence protein (EGFP), a reporter protein, to follow redistribution of Phd both by means of confocal microscopy and biochemical techniques in living neuronal NG 108-15 hybrid cells challenged with prostaglandin E1 (PGE1). The cells were transiently transfected to express Phd fused to the C-terminus of EGFP, or to express EGFP only. Overexpression of the proteins is implied by FACS analysis as well as by western blot technique, and the functional integrity of EGFP-tagged Phd was confirmed by its ability to elevate cAMP accumulation. Time-lapse imaging of single living cells by means of confocal microscopy revealed that exposure to prostaglandin causes EGFP/Phd, which is evenly spread throughout the cell, to relocate towards the membrane within few minutes. Fluorescence associated with the cell nucleus displayed little rearrangement. The principle finding that prostaglandin triggers translocation of Phd from cytosol to the cell periphery was verified with membranes prepared from EGFP/Phd expressing cells. We found maximal concentrations of membrane associated fluorescent material 5 to 7 min upon prostaglandin exposure. The present study reports for living NG 108-15 hybrid cells that PGE1 stimulation causes cytosolic Phd to translocate towards the membrane, where it is believed to bind to G protein subunits such as Gbetagamma and Galphas.

Correlates and prevalence of benzodiazepine use in community-dwelling elderly

OBJECTIVE

To describe the prevalence of benzodiazepine use, sociodemographic and physical health factors associated with use, dosages taken, and directions for use among individuals aged 65 years and older.

DESIGN

Cross-sectional analysis of baseline data from the community-based, prospective observational Cardiovascular Health Study.

PATIENTS/PARTICIPANTS

Medicare eligibility lists from four U.S. communities were used to recruit a representative sample of 5,201 community-dwelling elderly, of which 5,181 participants met all study criteria.

MEASUREMENTS AND MAIN RESULTS

Among participants, 511 (9.9%) were taking at least one benzodiazepine, primarily anxiolytics (73%). Benzodiazepines were often prescribed to be taken pro re nata (PRN "as needed"), and 36.5% of prescriptions with instructions to be taken regularly were taken at a dose lower than prescribed. Reported over-the-counter (OTC) sleep aid medication use was 39.2% in benzodiazepine users and 3.3% in nonusers. In a multivariate logistic model, the significant independent correlates of benzodiazepine use were being white (odds ratio [OR] 1.9; 95% confidence interval [CI] 1.0, 3.4), female (OR 1.7; CI 1.4, 2.2), and living in Forsyth County, North Carolina, or Washington County, Maryland, compared with living in Sacramento County, California, or Allegheny County, Pennsylvania (OR 2.3; CI 1.4, 2.2); having coronary heart disease (OR 1.6; CI 1.2, 2.1), health status reported as poor or fair (OR 1.8; CI 1.4, 2.3), self-reported diagnosis of nervous or emotional disorder (OR 6.7; CI 5.1, 8.7), and reporting use of an OTC sleep aid medication (OR 18.7; CI 14.1, 24.7).

CONCLUSIONS

One in 10 participants reported taking a benzodiazepine, most frequently an anxiolytic, often at a lower dose than prescribed and usually PRN. The high prevalence of OTC sleep aid medication and benzodiazepine use may place the patient at increased risk of psychomotor impairment. Physicians should assess OTC sleep aid medication use when prescribing benzodiazepines.

Positron emission tomography analysis of [1-(11)C] acetate kinetics in short-term hibernating myocardium

BACKGROUND

Modeling of the time-[1-(11)C]acetate activity curve assumes a constant concentration of labeled tricarboxylic acid cycle intermediates and associated metabolites, such as glutamate and aspartate, which may, however, decrease in short-term hibernating myocardium.

METHODS AND RESULTS

In 12 anesthetized pigs, [1-(11)C]acetate was injected as a bolus into the cannulated left anterior descending coronary artery during normoperfusion, inotropic stimulation, and early (5 to 45 minutes) and prolonged ischemia (60 to 90 minutes). Regional myocardial oxygen consumption (MVO2, microliters per minute per gram) was measured, and the absence of necrosis was verified by triphenyl tetrazolium chloride staining. Inotropic stimulation increased MVO2 from 52.5+/-7.4 to 195.4+/-36.2 (mean+/-SD) and the rate constant (kmono, minutes[-1]) of [1-(11)C]acetate clearance from 0.094+/-0.018 to 0.322+/-0.076. During early ischemia, MVO2 and kmono were decreased to 24.3+/-8.5 and 0.061+/-0.011, respectively. Kmono closely correlated to MVO2 during normoperfusion, inotropic stimulation, and early ischemia. In short-term hibernating myocardium, however, at an unchanged MVO2, kmono increased toward control values (0.080+/-0.014). Myocardial glutamate and aspartate concentrations (biopsies) decreased to 47+/-26% and 77+/-18%; the peak count rate decreased to 66+/-22% of its respective control value. After correction for the decreases in glutamate and aspartate or in peak count rate, kmono was again decreased (0.050+/-0.016 or 0.052+/-0.014, respectively), and a close relationship to MVO2 was restored.

CONCLUSIONS

Kmono correlates to MVO2 in short-term hibernating myocardium when the decreases in aspartate and glutamate or in peak count rate are considered.

Phosducin expression in NG 108-15 hybrid cells enhances prostaglandin E1 stimulated adenylate cyclase activity

Phosducin (Phd), a cytosolic protein, has been proposed to compete with certain receptor kinases for Gbetagamma of heterotrimeric G proteins, and may inhibit GTPase activity of G alpha s. These suggestions together with the enhancing effect of Phd on odorant-induced cAMP accumulation let us assume a stimulatory action of the protein on intracellular signaling. Therefore, this investigation was designed to examine the excitatory effect of PGE1 on signal transmission in neuroblastoma x glioma hybrid cells (NG 108-15) overexpressing Phd. The neuronal cells stably expressing Phd were found to display a 3 to 4-fold increased sensitivity to PGE1 as compared to wild type cells, using cAMP accumulation as measure. Examination of membranes prepared from Phd-overexpressing cells revealed an elevated GTPase activity as indicated by the formation of 32Pi upon PGE1 challenge. This activity was inhibited by exogenous Phd. In addition, receptor independent stimulation of adenylate cyclase by forskolin reveals an increased formation of cAMP in Phd expressing cells, which is accompanied by an increased binding of [3H]forskolin. The findings let us propose that Phd elevates intracellular levels of functional G alpha s which accounts for the increased response to PGE1.

Activity restriction and prior relationship history as contributors to mental health outcomes among middle-aged and older spousal caregivers

In a sample of cancer patients (n = 75) and spousal caregivers (24 men and 51 women), restriction in caregiver routine activities mediated associations between caregiving stress (patient symptom severity) and caregiver depressed affect and resentment. Moreover, the antecedents and affective consequences of caregiver activity restriction were consistent with the theory of communal relationships (e.g., M. S. Clark & J. Mills, 1979, 1993). If a relationship had been communal in the past (i.e., characterized by mutual concern for and responsiveness to one another's needs), activity restriction was predicted by intimacy and affectional loss (rather than by the severity of patient symptoms) and in turn predicted caregiver depressed affect. Among caregivers in less communal relationships, activity restriction was predicted by severity of patient symptoms (rather than by intimacy and affectional loss) and in turn predicted resentment of care recipients and the caregiving role.

Caregiving from the recipient's perspective: negative reactions to being helped

This study investigated predictors of negative reactions to assistance provided to a physically disabled spouse (n = 276, M age: 76.6 years) and the consequences that negative reactions may have for the mental health of the care recipient. Nearly 40% of recipients reported some emotional distress in response to help they received. Fatalistic attitudes, perceived control, and lower self-esteem predicted greater helping distress, whereas lower self-esteem, fatalistic beliefs, and marital conflict were especially likely to lead to helping distress for those who received higher levels of assistance. Helping distress was also found to predict depression as much as 1 year later, suggesting that there may be long-term consequences of negative reactions to assistance. These findings have important implications for the study of caregiving and the relationship between physical impairment and depression.

Expression of calcium regulatory proteins in short-term hibernation and stunning in the in situ porcine heart

BACKGROUND

Myocardial hibernation and stunning are characterised by a reversible contractile dysfunction during and after ischaemia, respectively. Calcium homeostasis might be disturbed in hibernation and stunning due to altered expression of cardiac proteins involved in calcium handling.

METHODS

In enflurane-anaesthetised swine the coronary blood flow through the left anterior descending coronary artery was decreased to reduce regional contractile function (microsonometry) by approximately 50%. In transmural biopsies obtained during ischaemia and reperfusion creatine phosphate as well as the expression of sarcoplasmic reticulum calcium ATPase (SERCA), phospholamban (PLB), calsequestrin (CSQ), and troponin inhibitor (TnI) were determined.

RESULTS

During ischaemia creatine phosphate, after an initial reduction, recovered back to control values, and necrosis was absent (hibernation). After 90 min of ischaemia the myocardium was reperfused for 120 min but regional contractile function continued to be depressed (stunning). PLB, SERCA, CSQ, and TnI proteins were unchanged during ischaemia as well as reperfusion. Likewise, levels of PLB and SERCA mRNAs were unchanged.

CONCLUSION

It is concluded that other mechanisms than altered expression of these regulating proteins underlie the contractile dysfunction observed during acute ischaemia, short-term hibernation and stunning.

Disinhibition in the gamma motoneuron circuitry: a neglected mechanism for understanding myofascial pain syndromes?

Dysregulation in the gamma motoneuron circuitry is proposed as one mechanism to explain the development of trigger point activity in myofascial pain syndrome. Dysregulation in this context is defined operationally as significantly (and functionally) different levels of electrical activity detected in the same muscle on the left and right sides of the body that is persistently present with movement of that muscle. Neurophysiological concepts as they pertain to muscles and motor control principles are reviewed. Research is integrated that ties together material from diverse fields of psychology and medicine. Dysregulation in the gamma motoneuron circuitry may lead to disinhibition of muscle that causes it to remain hyperactive after contraction, generate excessive electrical activity during movement, and/or inappropriately coactivate with other muscles during movement. Any or all of these phenomena may occur with dysregulation. Such dysregulation may be corrected by learning. Immediate clinical implications are discussed, including the addition of specifically targeted neuromuscular retraining procedures via surface electromyography, as well as some conceptual and research issues that require further clarification.

Thiols protect the inhibition of myocardial aconitase by peroxynitrite

Peroxynitrite (ONOO-) is a potent inhibitor of myocardial aconitase. Because ONOO- reacts with sulfhydryl moieties, we investigated whether thiols protect against ONOO(-)-mediated inhibition of aconitase. Aconitase activity was examined in ventricular homogenates prepared from freshly isolated rat hearts. Peroxynitrite, but not the nitric oxide donor S-nitroso-N-acetyl-d,l-penicillamine (0.03-300 microM), inhibited aconitase activity (IC50 = 47 +/- 6 microM). L-Cysteine (0.03-3 mM), glutathione (0.03-3 mM), and N-(2-mercaptoproprionyl)-glycine (MPG, 0.1-3 mM) protected against the inhibitory effect of ONOO- (100 microM) with the rank order of potency of MPG > glutathione > L-cysteine. D-Cysteine (3 mM) had a protective effect similar to L-cysteine, but L-cystine, the oxidized form of L-cysteine, offered no protection. Ferrous ammonium sulfate (1 mM) markedly enhanced the protection provided by L-cysteine, but not by glutathione or MPG. Thiols protect myocardial aconitase against inhibition by ONOO- in a manner which is sulfhydryl group dependent and not stereospecific. The protection is related to the maintenance of the redox state of the iron-sulfur cubane cluster and cysteine residues at the active site of the enzyme. Both naturally occurring thiols and thiol-based drugs may be useful to protect the heart during ischemia-reperfusion injury where there is an excessive production of ONOO-.

Prevention of ischemic preconditioning only by combined inhibition of protein kinase C and protein tyrosine kinase in pigs

In rabbits, inhibition of either protein kinase C or protein tyrosine kinase abolishes the infarct size reduction achieved by ischemic preconditioning. In pigs, however, inhibition of protein kinase C does not attenuate ischemic preconditioning. The present study tested whether inhibition of protein tyrosine kinase alone or in combination with inhibition of protein kinase C interferes with ischemic preconditioning in pigs. In 29 enflurane-anesthetized pigs, the LAD was cannulated and perfused from an extracorporeal circuit. Protein tyrosine kinase and protein kinase C were inhibited by continuous intracoronary infusion of genistein (5x10(-6) mol/l) and staurosporine (10(-7) mol/l), respectively. Subendocardial blood flow (ENDO) was measured with microspheres. Infarct size was analysed by TTC staining (% of LV area at risk) following 90 min low-flow ischemia and 120 min reperfusion. In the presence of genistein, 90 min ischemia at an ENDO of 0.06+/-0.01 (+/-s.e.m.) ml/min/g resulted in an infarct size of 16.7+/-4.2% (n=8). With genistein, ischemic preconditioning by 10 min ischemia and 15 min reperfusion still reduced infarct size to 6.5+/-2.7% (ENDO: 0.05+/-0. 01 ml/min/g, n=7, P<0.05). In the presence of both genistein and staurosporine, infarct size following 90 min ischemia was 14.1+/-3. 6% (ENDO: 0.06+/-0.01 ml/min/g, n=7). With genistein and staurosporine, ischemic preconditioning no longer reduced infarct size significantly (11.5+/-3.1%, ENDO: 0.06+/-0.01 ml/min/g, n=7). The effective attenuation of ischemic preconditioning only by simultaneous inhibition of both, protein kinase C and protein tyrosine kinase, suggests a complex signal cascade involving both protein kinases.

Measurement choices in multi-site studies of outcomes in dementia

This paper summarizes the measurement choices made by selected current or recently completed multi-site projects with a common emphasis on measuring outcomes in dementia. Information on number of items and scoring, reason(s) for selecting the measure, and reliability and validity of the measure (either citations providing this information or a report of pertinent unpublished findings) is presented for eight domains: cognition, behavioral symptoms, physical health status, physical functioning and self-care abilities, quality of life, family/staff caregiver outcomes, service use, and cost. We found considerable reliance on the published literature as a guide to measurement choice, motivated largely by measures' superior psychometric properties, their ubiquity in the literature, and/or their brevity or ease of use. There is still evidence of "starting from scratch" in some domains, however. To the extent that these projects reflect the state of the art in dementia-relevant outcomes research, we conclude that comparison of outcomes across studies will continue to be problematic. However, as long as dissemination of methodological as well as substantive findings continues to characterize outcome studies in dementia, there is hope that a more congruent view of how to assess key outcomes in dementia will emerge.