Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 182, July 1978

This bibliography lists 165 reports, articles, and other documents introduced into the NASA scientific and technical information system in June 1978

Prognosis of the state of health of a person under spaceflight conditions

Methods of predicting the state of health and human efficiency during space flight are discussed. Diversity of reactions to the same conditions, development of extrapolation methods of prediction, and isolation of informative physiological indexes are among the factors considered

Soluble ST2 levels and left ventricular structure and function in patients with metabolic syndrome

Background: A biomarker that is of great interest in relation to adverse cardiovascular events is soluble ST2 (sST2), a member of the interleukin family. Considering that metabolic syndrome (MetS) is accompanied by a proinflammatory state, we aimed to assess the relationship between sST2 and left ventricular (LV) structure and function in patients with MetS. Methods: A multicentric, cross-sectional study was conducted on180 MetS subjects with normal LV ejection fraction as determined by echocardiography. LV hypertrophy (LVH) was defined as an LV mass index greater than the gender-specific upper limit of normal as determined by echocardiography. LV diastolic dysfunction (DD) was assessed by pulse-wave and tissue Doppler imaging. sST2 was measured by using a quantitative monoclonal ELISA assay. Results: LV mass index (β=0.337, P<0 .001, linear regression) was independently associated with sST2 concentrations. Increased sST2 was associated with an increased likelihood of LVH [Exp (B)=2.20, P=0.048, logistic regression] and increased systolic blood pressure [Exp (B)=1.02, P=0.05, logistic regression]. Comparing mean sST2 concentrations (adjusted for age, body mass index, gender) between different LV remodeling patterns, we found the greatest sST2 level in the group with concentric hypertrophy. There were no differences in sST2 concentration between groups with and without LV DD. Conclusions: Increased sST2 concentration in patients with MetS was associated with a greater likelihood of exhibiting LVH. Our results suggest that inflammation could be one of the principal triggering mechanisms for LV remodeling in MetS

Norming the MAD-AS to the STAXI-2 in a Hypertensive Population

Development of the Mahan and DiTomasso Anger Scale (MAD-AS) provided a valid and preferable alternative to the existing, lengthy tests of anger which are currently available. However, the MAD-AS was developed on a clinical, psychiatric population, and only one other study to date has attempted to utilize this test on a normal population. With strong links between anger and adverse physical health, and an ongoing controversy over whether anger expression versus anger suppression contributes more highly to the development and maintenance of hypertension, a prospective study measuring anger with established hypertensive subjects is being proposed utilizing both the MAD-AS, as an experimental instrument, and the State-Trait Anger Expression Inventory - 2 (STAXI-2), as an established instrument. This study hopes to lend not only more validity to the MAD-AS with a medical population, but also more evidence to the above controversy

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 192

This bibliography lists 247 reports, articles, and other documents introduced into the NASA scientific and technical information system in March 1979

Prognostic implications of left ventricular hypertrophy

Left ventricular hypertrophy (LVH) was one of the earliest studied echocardiographic characteristics of the left ventricle. As the myriad of measurable metrics has multiplied over recent years, this reliable and relevant variable can often be overlooked. In this paper, we discuss appropriate techniques for accurate analysis, underlying pathophysiology, and the contributions from various risk factors. The prognostic implications of LVH on stroke, serious arrhythmias, and sudden cardiac death are reviewed. Finally, we examine the effect of therapy to reduce LVH and the resultant clinical outcomes. (C) 2018 Elsevier Inc. All rights reserved

Aging is associated with an earlier arrival of reflected waves without a distal shift in reflection sites

Background-Despite pronounced increases in central pulse wave velocity (PWV) with aging, reflected wave transit time (RWTT), traditionally defined as the timing of the inflection point (T-INF) in the central pressure waveform, does not appreciably decrease, leading to the controversial proposition of a "distal-shift" of reflection sites. T-INF, however, is exceptionally prone to measurement error and is also affected by ejection pattern and not only by wave reflection. We assessed whether RWTT, assessed by advanced pressure-flow analysis, demonstrates the expected decline with aging. Methods and Results-We studied a sample of unselected adults without cardiovascular disease (n=48; median age 48 years) and a clinical population of older adults with suspected/established cardiovascular disease (n=164; 61 years). We measured central pressure and flow with carotid tonometry and phase-contrast MRI, respectively. We assessed RWTT using wave-separation analysis (RWTTWSA) and partially distributed tube-load (TL) modeling (RWTTTL). Consistent with previous reports, T-INF did not appreciably decrease with age despite pronounced increases in PWV in both populations. However, aging was associated with pronounced decreases in RWTTWSA (general population -15.0 ms/decade, P<0.001; clinical population -9.07 ms/decade, P=0.003) and RWTTTL (general -15.8 ms/decade, P<0.001; clinical -11.8 ms/decade, P<0.001). There was no evidence of an increased effective reflecting distance by either method. TINF was shown to reliably represent RWTT only under highly unrealistic assumptions about input impedance. Conclusions-RWTT declines with age in parallel with increased PWV, with earlier effects of wave reflections and without a distal shift in reflecting sites. These findings have important implications for our understanding of the role of wave reflections with aging

Entwicklung und Validierung der in vivo zeitharmonischen Ultraschall-Elastografie des menschlichen Gehirns für die klinische Anwendung

Motivation: In neurology, the determination of intracranial pressure (ICP) is of central importance for the diagnosis of brain damage. However, reliable ICP measurements are realized by invasive techniques such as lumbar puncture or surgically implanted pressure probes. Cerebral stiffness (CS) measured by elastography could be a parameter sensitive to ICP variations. However, CS is currently measured exclusively by magnetic resonance elastography, which is associated with long examinations and limited availability. Time harmonic shear wave excitation used in magnetic resonance elastography combined with transcranial ultrasound (cerebral THE) can provide reproducible and stable elastograms over a large field-of-view in real-time. Initial applications of cerebral THE in healthy volunteers during performance of the Valsalva maneuver demonstrated sensitivity of CS to blood flow and pressure changes in the brain. The goal of this PhD project was to optimize and validate cerebral THE that I previously developed to quantify CS, identify it as a marker of cerebral perfusion, and provide initial evidence for the potential clinical application of the method as a noninvasive technique for estimating ICP. Methods: To this end, I conducted two studies in healthy volunteers aimed at artificial manipulation of cerebral blood flow: (i) I investigated the effect of hypercapnia during breathing of carbon dioxide-enriched gas and (ii) the effect of dehydration and oral rehydration on CS measured by cerebral THE. Finally, I applied cerebral THE in a pilot clinical study in patients with idiopathic intracranial hypertension (IIH) who underwent lumbar puncture (LP) along with invasive quantification of cerebrospinal fluid (CSF) opening pressure and, if necessary, CSF drainage. Results: Hypercapnia increased CS by 6 ± 4% above baseline. In contrast, dehydration of healthy volunteers resulted in a decrease in CS of 4 ± 2%, whereas CS returned to baseline after oral rehydration. In patients with IIH, CS was 16 ± 5% higher than in healthy volunteers and correlated positively with CSF opening pressure (r = 0:69, p < 0:001). Approximately 30 min after LP, patients’ CS values were within the range of CS values in healthy volunteers. Conclusion: Cerebral THE proved to be a reproducible, stable imaging technique for real-time determination of CS. This project demonstrated that changes in CS are closely associated with changes in cerebral perfusion and ICP. These results suggest that cerebral THE may be a promising noninvasive diagnostic tool for determining ICP in routine clinical practice.Motivation: In der Neurologie ist die Bestimmung des intrakraniellen Drucks (ICP) von zentraler Bedeutung für die Diagnose von Hirnschäden. Zuverlässige ICP-Messungen werden jedoch durch invasive Techniken wie die Lumbalpunktion oder chirurgisch implantierte Drucksonden realisiert. Die mittels Elastografie gemessene zerebrale Steifigkeit (CS) könnte ein Parameter sein, der empfindlich auf ICP-Schwankungen reagiert. Allerdings wird die CS derzeit ausschließlich mit der Magnetresonanz-Elastografie gemessen, die mit langen Untersuchungen und begrenzter Verfügbarkeit verbunden ist. Zeitharmonische Scherwellenanregung, wie sie in der Magnetresonanz-Elastografie verwendet wird, kombiniert mit transkraniellem Ultraschall (zerebrale THE) kann reproduzierbare, stabile Elastogramme über ein großes Sichtfeld in Echtzeit liefern. Erste Anwendungen der zerebralen THE bei gesunden Probanden während der Durchführung des Valsalva-Manövers zeigten, dass die CS empfindlich auf Blutflussund Druckänderungen im Gehirn reagiert. Ziel dieses Promotionsprojekts war die Optimierung und Validierung der zerebralen THE, welche ich zuvor entwickelt habe, um CS zu quantifizieren, als Marker für zerebrale Perfusion zu identifizieren und erste Beweise für die potenzielle klinische Anwendung der Methode als nichtinvasive Technik zur Abschätzung des ICP zu liefern. Methoden: Zu diesem Zweck führte ich zwei Studien an gesunden Probanden durch, welche die künstliche Manipulation des zerebralen Blutflusses zum Ziel hatten: (i) Ich untersuchte die Auswirkung von Hyperkapnie während der Atmung von mit Kohlendioxid angereichertem Gas und (ii) die Auswirkung von Dehydrierung und oraler Rehydrierung auf die durch zerebrale THE gemessene CS. Schließlich habe ich die zerebrale THE in einer klinischen Pilotstudie bei Patienten mit idiopathischer intrakranieller Hypertension (IIH) angewandt, bei denen eine Lumbalpunktion (LP) zusammen mit einer invasiven Quantifizierung des Liquoröffnungsdrucks und, falls erforderlich, einer Liquordrainage durchgeführt wurde. Ergebnisse: Hyperkapnie erhöhte den CS um 6 4% über den Ausgangswert. Im Gegensatz dazu führte die Dehydratation gesunder Probanden zu einem Rückgang des CS um 4 2%, während der CS nach oraler Rehydrierung wieder den Ausgangswert erreichte. Bei Patienten mit IIH war die CS um 16 5% höher als bei gesunden Probanden und korrelierte positiv mit dem Liquoröffnungsdruck (r = 0:69, p < 0:001). Etwa 30 Minuten nach der LP lagen die CS Werte der Patienten im Bereich der CS Werte gesunder Probanden. Schlussfolgerung: Die zerebrale THE erwies sich als reproduzierbares, stabiles bildgebendes Verfahren zur Echtzeit-Bestimmung der CS. Dieses Projekt zeigte, dass Änderungen des CS eng mit Änderungen der zerebralen Perfusion und des ICP verbunden sind. Diese Ergebnisse deuten darauf hin, dass die zerebrale THE ein vielversprechendes nichtinvasives Diagnoseinstrument zur Bestimmung des ICP in der klinischen Routinepraxis sein könnte