Improvement in exercise capacity of candidates awaiting heart transplantation

OBJECTIVES

This study determined the frequency of improvement in peak oxygen uptake and its role in reevaluation of candidates awaiting heart transplantation.

BACKGROUND

Ambulatory candidates for transplantation usually wait > 6 months to undergo the procedure, and during this period symptoms may lessen, and peak oxygen uptake may improve. Whereas initial transplant candidacy is based increasingly on objective criteria, there are no established guidelines for reevaluation to determine who can leave the active waiting list.

METHODS

All ambulatory transplant candidates with initial peak oxygen uptake < 14 ml/kg per min were identified. Of 107 such patients listed, 68 survived without early deterioration or transplantation to undergo repeat exercise. A strategy of reevaluation using specific clinical criteria and exercise performance was tested to determine whether patients with improved oxygen uptake could safely be followed without transplantation.

RESULTS

In 38 of the 68 patients, peak oxygen uptake increased by > or = 2 ml/kg per min to a level > or = 12 ml/kg per min after 6 +/- 5 months, together with an increase in anaerobic threshold, peak oxygen pulse and exercise heart rate reserve and a decrease in heart rate at rest. Increased peak oxygen uptake was accompanied by stable clinical status without congestion in 31 of 38 patients, and these 31 were taken off the active waiting list. At 2 years, their actuarial survival rate was 100%, and the survival rate without relisting for transplantation was 85%.

CONCLUSION

Reevaluation of exercise capacity and clinical status allowed removal of 31 (29%) of 107 ambulatory transplant candidates from the waiting list with excellent early survival despite low peak oxygen uptake on initial testing. The ability to increase peak oxygen uptake, particularly with increased peak oxygen pulse, may indicate improved prognosis as well as functional capacity and, in combination with stable clinical status, may be an indication to defer transplantation in favor of more compromised candidates.

Effects of orexin and glucose microinjected into the hypothalamic paraventricular nucleus on gastric acid secretion in conscious rats

BACKGROUND

Orexin-A is a novel peptide that appears to play a role in regulation of gastric acid secretion. However, little is known about sites of its action. In addition, evidences suggest that some of orexin-A neurons respond to glucose. In this study, we address the hypothesis which demonstrates that orexin-A and glucose act in the hypothalamic paraventricular nucleus (PVN) to increase gastric acid secretion and juice volume in pyloric-ligated conscious rats.

METHODS

Male Wistar rats were implanted with guide canula directed to the PVN. Orexin-A (3-10 μg), glucose (350-750 ng) SB334867 (6-20 μg) were microinjected. The effect of pretreatment with an orexin-1 receptor antagonist, SB334867, on orexin-A and D-glucose induced acid secretion was assessed. Gastric acid secretion was measured using the pylorus-ligation method, and the amount of gastric acid was determined by titration with 0.01 N NaOH to a pH of 7.0.

KEY RESULTS

Intraparaventricular injection of orexin-A or D-glucose stimulated gastric acid secretion in a dose-dependent manner. The PVN injections of orexin-A receptor antagonist, SB334867, were associated with gastric acid secretion decrease and inhibited effects of PVN-injected orexin-A. Orexin-stimulated gastric acid secretion was decreased (~40%) after PVN lesions. Glucose-stimulated gastric acid secretion was also suppressed by intraperitoneal (IP) injection of SB334867. In addition, it was observed that co-injection of orexin-A and glucose at ineffective doses increased gastric secretion significantly.

CONCLUSIONS & INFERENCES

We suggest that orexin-A and glucose effects on the PVN stimulate gastric acid secretion. This stimulatory effect is probably mediated by orexin-1 receptors.

Underutilization and clinical benefits of angiotensin-converting enzyme inhibitors in patients with asymptomatic left ventricular dysfunction

Despite evidence of therapeutic benefit of angiotensin-converting enzyme (ACE) inhibitors for congestive heart failure and asymptomatic left ventricular (LV) dysfunction, recent studies suggest that in heart failure patients, rates of ACE inhibitor usage in clinical practice remain low. In this study, the medical records of 107 patients with documented LV dysfunction were investigated for patterns of ACE inhibitor usage; 6-month and 1-year outcomes and event rates were evaluated. At index admission, 48% patients did not receive ACE inhibitor treatment, 32% were initiated on treatment, 19% continued on a prior regimen, and 1% were discontinued. Patients seen by a cardiologist were more likely to receive ACE inhibitor treatment (53% vs 35%, p = 0. 172), as were patients with histories of hypertension (60% vs 40%, p = 0.044) or myocardial infarction (56% vs 44%, p = 0.221). Significantly shorter hospitalizations (5.9 vs 9.5 days, p = 0.001) were noted for patients with on-going ACE inhibitor treatment compared with those receiving newly initiated treatment or no treatment. At time of hospital discharge, 102 patients were alive. Of 54 patients who received ACE inhibitors, 67% received an insufficient dose. At a 6-month follow-up, of 51 patients on ACE inhibitors, 23% died or were readmitted to hospital compared with 55% of nonusers (p = 0.001). At 1 year, this event rate was 31% among ACE inhibitor users versus 71% among nonusers (p < 0.0001). Bivariate and multivariate analysis revealed absence of ACE inhibitor use as the only significant variable associated with the event rate (p < 0.0011). Thus, about half of patients with asymptomatic LV dysfunction received ACE inhibitors; 2/3 of these did not receive a sufficient dose. ACE inhibitor usage increased with involvement of a cardiologist, presence of coexistent hypertension, or prior myocardial infarction. Ongoing ACE inhibitor therapy was associated with shorter hospitalizations and fewer hospital readmissions or deaths.

Gastric acid secretion induced by paraventricular nucleus microinjection of orexin A is mediated through activation of neuropeptide Yergic system

Very recently, we have reported that the modulatory effect of PVN on gastric acid secretion may be mediated through the orexin fibers and/or orexin-responsive neurons. In this study, we address the hypothesis which demonstrates the existence of a putative orexin A - neuropeptide Y Y1/Y5 receptors interaction to increase gastric acid secretion in pyloric-ligated conscious rats. Male Wistar rats were implanted with guide canula directed to the PVN and lateral ventricle. Intracerebroventricular (ICV) microinjections of GR-231118 (Y1 receptor antagonist) and CGP-71683 (Y5 receptor antagonist) on gastric acid secretion were considered. The effect of pretreatment with Y1 receptor antagonist, GR-231118, and Y5 receptor antagonist, CGP-71683, on PVN orexin A-induced acid secretion was assessed. Gastric acid secretion was measured using the pylorus-ligation method, and the amount of gastric acid was determined by titration with 0.01N NaOH to a pH of 7.0.

KEY RESULTS

ICV microinjections of GR-231118 and CGP-71683 decreased acid secretion by 25±0.05% and 67±0.02%, respectively. ICV microinjections of GR-231118 and CGP-71683 inhibited effects of PVN-injected orexin-A on acid secretion. We suggest that Y1 and Y5 receptors stimulate gastric acid secretion and the stimulatory effect of PVN orexin receptors on gastric acid secretion may be mediated via interactions, at least in part, through activation of Y1 and Y5 receptors. These neural pathways may play key roles in the orexinergic action of orexins in the cephalic phase of gastric acid secretion.

Ecotoxicological risk of polycyclic aromatic hydrocarbons (PAHs) in urban soil of Isfahan metropolis, Iran

Concentration, distribution, probable sources, and health risks of 16 polycyclic aromatic hydrocarbons (PAHs) were investigated in 52 soil samples collected within a radius 50 km from Isfahan metropolis center. Total concentration of PAHs ranged from 57.70 to 11,730.08 μg/kg averaging 2,000.56 μg/kg. Spatial PAH profiles were site-specific and higher concentration of PAHs was observed in the vicinity of industrial zones within Isfahan metropolis. The molecular indices, ring classes, and principal component analysis indicated that the sources of PAHs were both geogenic and pyrogenic. The incremental lifetime cancer risks of exposure to soil PAHs for adults and children living in the study area were 2.3×10(-2) and 2.2×10(-3), respectively. The results suggest that current PAHs levels in Isfahan metropolis soil are highly carcinogenic and may hold a serious health risk for local resident.

Sorry, not sorry: The effect of social power on transgressors' apology and nonapology

The current research investigated the role of transgressors' social power on their motivation to apologize or not. Based on power approach theory (Keltner et al., 2003), we predicted that high-power transgressors would be less motivated to apologize and more motivated to engage in nonapology (e.g., shifting blame, minimizing the transgression) than their low-power counterparts. We further predicted that the relation between social power and apology and nonapology would be explained by transgressors' self-other focus. Four multimethod (nonexperimental, experimental), multisample (community, undergraduate) studies supported our predictions. Results are discussed within the context of the extant social motivation literature and applied implications. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Determining the Diagnostic Value of Venous Sinus Density Indices in Non-Contrast Brain CT Scan for Early Diagnosis of Cerebral Venous Sinus Thrombosis

BACKGROUND AND AIM

A non-contrast brain CT Non-contrast computed tomography (NCCT) scan is a valuable and cost-effective way to detect cerebral venous sinus thrombosis (CVST) during its acute phase. The goal of this study was to evaluate how effective this diagnostic approach is, including its various density indices, to enable a more precise and timely diagnosis of this debilitating condition.

METHOD

This retrospective case-control study was conducted on 88 patients with suspected acute CVST. We analyzed NCCT scans of patients with suspected CVST using a Bayesian regression model with a 95% confidence level. We also conducted ROC analysis in R4.1.0 to determine the optimal cut-off point.

RESULT

We discovered a significant variance in the average sinus attenuation when comparing patients with acute CVST (p < 0.001). By utilizing an optimal cutoff of 61 HU (Hounsfield unit), we achieved sensitivities of 77.1% and specificities of 92.5% for average sinus attenuation. In addition, the optimal cutoff for standardized parameters included the ratios of HU/H (Hematocrit), HU/ICA (internal carotid artery), HU/BA (basilar artery), HU/FRONTAL lobe, HU/TEMPORAL lobe, and HU-BA, which were 1.41, 1.52, 1.63, 1.6, 1.6, and 23, respectively (p < 0.001). Area under the ROC curve for absolute venous Hounsfield was 0.88.

CONCLUSION

NCCT is a reliable diagnostic approach for acute cerebral venous sinus thrombosis in emergency scenarios. Standardized parameters of absolute Hounsfield unit venous sinus thrombosis increase diagnosis accuracy. It is suggested to use these parameters as a complement to each other for more accurate diagnosis.