Role of K(ATP)(+) channels in regulation of systemic, pulmonary, and coronary vasomotor tone in exercising swine

The role of ATP-sensitive K(+) (K(ATP)(+)) channels in vasomotor tone regulation during metabolic stimulation is incompletely understood. Consequently, we studied the contribution of K(ATP)(+) channels to vasomotor tone regulation in the systemic, pulmonary, and coronary vascular bed in nine treadmill-exercising swine. Exercise up to 85% of maximum heart rat

Cube law, condition factor and weight-length relationships: history, meta-analysis and recommendations

This study presents a historical review, a meta-analysis, and recommendations for users about weight–length relationships, condition factors and relative weight equations. The historical review traces the developments of the respective concepts. The meta-analysis explores 3929 weight–length relationships of the type W = aLb for 1773 species of fishes. It shows that 82% of the variance in a plot of log a over b can be explained by allometric versus isometric growth patterns and by different body shapes of the respective species. Across species median b = 3.03 is significantly larger than 3.0, thus indicating a tendency towards slightly positive-allometric growth (increase in relative body thickness or plumpness) in most fishes. The expected range of 2.5 < b < 3.5 is confirmed. Mean estimates of b outside this range are often based on only one or two weight–length relationships per species. However, true cases of strong allometric growth do exist and three examples are given. Within species, a plot of log a vs b can be used to detect outliers in weight–length relationships. An equation to calculate mean condition factors from weight–length relationships is given as Kmean = 100aLb−3. Relative weight Wrm = 100W/(amLbm) can be used for comparing the condition of individuals across populations, where am is the geometric mean of a and bm is the mean of b across all available weight–length relationships for a given species. Twelve recommendations for proper use and presentation of weight–length relationships, condition factors and relative weight are given

Interferometry with Bose-Einstein Condensates in Microgravity

Atom interferometers covering macroscopic domains of space-time are a spectacular manifestation of the wave nature of matter. Due to their unique coherence properties, Bose-Einstein condensates are ideal sources for an atom interferometer in extended free fall. In this paper we report on the realization of an asymmetric Mach-Zehnder interferometer operated with a Bose-Einstein condensate in microgravity. The resulting interference pattern is similar to the one in the far-field of a double-slit and shows a linear scaling with the time the wave packets expand. We employ delta-kick cooling in order to enhance the signal and extend our atom interferometer. Our experiments demonstrate the high potential of interferometers operated with quantum gases for probing the fundamental concepts of quantum mechanics and general relativity.Comment: 8 pages, 3 figures; 8 pages of supporting materia

Length of hospital stay for elective electrophysiological procedures: a survey from the European Heart Rhythm Association

AIMS: Electrophysiological (EP) operations that have traditionally involved long hospital lengths of stay (LOS) are now being undertaken as day case procedures. The coronavirus disease-19 pandemic served as an impetus for many centres to shorten LOS for EP procedures. This survey explores LOS for elective EP procedures in the modern era. METHODS AND RESULTS: An online survey consisting of 27 multiple-choice questions was completed by 245 respondents from 35 countries. With respect to de novo cardiac implantable electronic device (CIED) implantations, day case procedures were reported for 79.5% of implantable loop recorders, 13.3% of pacemakers (PMs), 10.4% of implantable cardioverter defibrillators (ICDs), and 10.2% of cardiac resynchronization therapy (CRT) devices. With respect to CIED generator replacements, day case procedures were reported for 61.7% of PMs, 49.2% of ICDs, and 48.2% of CRT devices. With regard to ablations, day case procedures were reported for 5.7% of atrial fibrillation (AF) ablations, 10.7% of left-sided ablations, and 17.5% of right-sided ablations. A LOS ≥ 2 days for CIED implantation was reported for 47.7% of PM, 54.5% of ICDs, and 56.9% of CRT devices and for 54.5% of AF ablations, 42.2% of right-sided ablations, and 46.1% of left-sided ablations. Reimbursement (43-56%) and bed availability (20-47%) were reported to have no consistent impact on the organization of elective procedures. CONCLUSION: There is a wide variation in the LOS for elective EP procedures. The LOS for some procedures appears disproportionate to their complexity. Neither reimbursement nor bed availability consistently influenced LOS

Alterations in vasomotor control of coronary resistance vessels in remodelled myocardium of swine with a recent myocardial infarction

The mechanism underlying the progressive deterioration of left ventricular (LV) dysfunction after myocardial infarction (MI) towards overt heart failure remains incompletely understood, but may involve impairments in coronary blood flow regulation within remodelled myocardium leading to intermittent myocardial ischemia. Blood flow to the remodelled myocardium is hampered as the coronary vasculature does not grow commensurate with the increase in LV mass and because extravascular compression of the coronary vasculature is increased. In addition to these factors, an increase in coronary vasomotor tone, secondary to neurohumoral activation and endothelial dysfunction, could also contribute to the impaired myocardial oxygen supply. Consequently, we explored, in a series of studies, the alterations in regulation of coronary resistance vessel tone in remodelled myocardium of swine with a 2 to 3-week-old MI. These studies indicate that myocardial oxygen balance is perturbed in remodelled myocardium, thereby forcing the myocardium to increase its oxygen extraction. These perturbations do not appear to be the result of blunted β-adrenergic or endothelial NO-mediated coronary vasodilator influences, and are opposed by an increased vasodilator influence through opening of KATP channels. Unexpectedly, we observed that despite increased circulating levels of noradrenaline, angiotensin II and endothelin-1, α-adrenergic tone remained negligible, while the coronary vasoconstrictor influences of endogenous endothelin and angiotensin II were virtually abolished. We conclude that, early after MI, perturbations in myocardial oxygen balance are observed in remodelled myocardium. However, adaptive alterations in coronary resistance vessel control, consisting of increased vasodilator influences in conjunction with blunted vasoconstrictor influences, act to minimize the impairments of myocardial oxygen balance

Quantifying Fundus Autofluorescence in Patients With Retinitis Pigmentosa

Purpose Using quantitative fundus autofluorescence (qAF), we analyzed short-wavelength autofluorescent (SW-AF) rings in RP. Methods: Short-wavelength autofluorescent images (486 nm excitation) of 40 patients with RP (69 eyes) were acquired with a confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference. Mean qAF was measured in eight preset segments (qAF8) and in region of interest (ROI)-qAF (200–700 μm) within and external to the borders of the rings at superior, temporal, and inferior sites relative to the ring. For both groups, qAF in patients with RP was compared to age-similar and race/ethnicity-matched healthy eyes at equivalent retinal locations. Results: In 71% of eyes of RP patients, qAF8 acquired internal to the inner border of the ring, was within the 95% confidence interval (CI) for healthy eyes, while in the remaining RP eyes qAF8 was either higher or lower than the CI. Measured external to the ring, qAF8 values were within the CI in 47% of RP eyes with the other eyes being higher or lower. In 28% of sites measured by ROI-qAF within the SW-AF ring, values were above the 95% CI of healthy controls. Region of interest-qAF measured just external to the ring was within the CI of healthy eyes in 74% of locations. The average local elevation in qAF within the ring was approximately 15%. In SD-OCT scans, photoreceptor-attributable reflectivity bands were thinned within and external to the ring. Conclusions: Increased fluorophore production may be a factor in the formation of the SW-AF rings in RP

Diagnosis and neurosurgical treatment of glossopharyngeal neuralgia: clinical findings and 3-D visualization of neurovascular compression in 19 consecutive patients

Glossopharyngeal neuralgia is a rare condition with neuralgic sharp pain in the pharyngeal and auricular region. Classical glossopharyngeal neuralgia is caused by neurovascular compression at the root entry zone of the nerve. Regarding the rare occurrence of glossopharyngeal neuralgia, we report clinical data and magnetic resonance imaging (MRI) findings in a case series of 19 patients, of whom 18 underwent surgery. Two patients additionally suffered from trigeminal neuralgia and three from additional symptomatic vagal nerve compression. In all patients, ipsilateral neurovascular compression syndrome of the IX cranial nerve could be shown by high-resolution MRI and image processing, which was confirmed intraoperatively. Additional neurovascular compression of the V cranial nerve was shown in patients suffering from trigeminal neuralgia. Vagal nerve neurovascular compression could be seen in all patients during surgery. Sixteen patients were completely pain free after surgery without need of anticonvulsant treatment. As a consequence of the operation, two patients suffered from transient cerebrospinal fluid hypersecretion as a reaction to Teflon implants. One patient suffered postoperatively from deep vein thrombosis and pulmonary embolism. Six patients showed transient cranial nerve dysfunctions (difficulties in swallowing, vocal cord paresis), but all recovered within 1 week. One patient complained of a gnawing and burning pain in the cervical area. Microvascular decompression is a second-line treatment after failure of standard medical treatment with high success in glossopharyngeal neuralgia. High-resolution MRI and 3D visualization of the brainstem and accompanying vessels as well as the cranial nerves is helpful in identifying neurovascular compression before microvascular decompression procedure

Evidence for Avian Intrathoracic Air Sacs in a New Predatory Dinosaur from Argentina

Background: Living birds possess a unique heterogeneous pulmonary system composed of a rigid, dorsally-anchored lung and several compliant air sacs that operate as bellows, driving inspired air through the lung. Evidence from the fossil record for the origin and evolution of this system is extremely limited, because lungs do not fossilize and because the bellow-like air sacs in living birds only rarely penetrate (pneumatize) skeletal bone and thus leave a record of their presence. Methodology/Principal Findings: We describe a new predatory dinosaur from Upper Cretaceous rocks in Argentina, Aerosteon riocoloradensis gen. et sp. nov., that exhibits extreme pneumatization of skeletal bone, including pneumatic hollowing of the furcula and ilium. In living birds, these two bones are pneumatized by diverticulae of air sacs (clavicular, abdominal) that are involved in pulmonary ventilation. We also describe several pneumatized gastralia (‘‘stomach ribs’’), which suggest that diverticulae of the air sac system were present in surface tissues of the thorax. Conclusions/Significance: We present a four-phase model for the evolution of avian air sacs and costosternal-driven lung ventilation based on the known fossil record of theropod dinosaurs and osteological correlates in extant birds: (1) Phase I—Elaboration of paraxial cervical air sacs in basal theropods no later than the earliest Late Triassic. (2) Phase II—Differentiation of avian ventilatory air sacs, including both cranial (clavicular air sac) and caudal (abdominal air sac) divisions, in basal tetanurans during the Jurassic. A heterogeneous respiratory tract wit