Reconfigurable Low-Voltage Hexagonal Boron Nitride Nonvolatile Switches for Millimeter-Wave Wireless Communications

Recently, nonvolatile resistive switching memory effects have been actively studied in two-dimensional (2D) transition metal dichalcogenides and boron nitrides to advance future memory and neuromorphic computing applications. Here, we report on radiofrequency (RF) switches utilizing hexagonal boron nitride (h-BN) memristors that afford operation in the millimeter-wave (mmWave) range. Notably, silver (Ag) electrodes to h-BN offer outstanding nonvolatile bipolar resistive switching characteristics with a high ON/OFF switching ratio of 10¹¹ and low switching voltage below 0.34 V. In addition, the switch exhibits a low insertion loss of 0.50 dB and high isolation of 23 dB across the D-band spectrum (110 to 170 GHz). Furthermore, the S₂₁ insertion loss can be tuned through five orders of current compliance magnitude, which increases the application prospects for atomic switches. These results can enable the switch to become a key component for future reconfigurable wireless and 6G communication systems.

POS0684 IS UPADACITINIB CAPABLE OF IMPROVING PATIENT-REPORTED OUTCOMES OF RHEUMATOID ARTHRITIS IN A REAL-WORLD SETTING? RESULTS FROM THE POST-MARKETING OBSERVATIONAL UPwArds STUDY

Background

The efficacy of Upadacitinib (UPA), a selective Janus kinase inhibitor, has been evaluated in the SELECT clinical program 1-6. In addition, recent results from the non-interventional UPwArds study further confirmed UPAs clinical effectiveness regarding standard disease activity scores for rheumatoid arthritis (RA) in a real-world setting 7. However, patient-reported outcomes (PROs) as another cornerstone of clinical decision making yet remain to be addressed in the context of a post-marketing setting. This interim analysis, conducted after 250 patients had completed the 6-month follow-up visit, aims to fill this gap.

Objectives

To evaluate the change of selected PROs over 6 months in patients treated with UPA in a real-world data environment.

Methods

UPwArds is a prospective, open-label, multicenter, non-interventional, post-marketing study including adult patients with moderate-to-severe RA (swollen joint count [SJC28] ≥ 3 and inadequate response or intolerance to at least one previous disease-modifying antirheumatic drug). According to the German label, patients were treated with UPA 15 mg once daily, as monotherapy or in combination with methotrexate. For this analysis, the following PROs were included: 0-10 numerical rating scales (NRS) for pain and fatigue, the Health Assessment Questionnaire Disability Index (HAQ-DI), the duration and severity of morning stiffness, the Patient Health Questionnaire 9 (PHQ-9), and the Rheumatoid Arthritis Impact of Disease Questionnaire (RAID). Changes from baseline were evaluated for follow-up periods of 1 month, 3 months, and 6 months. Results are presented for the total sample using descriptive measures reflecting sample size (N), average values (standard deviation) for each assessment and average change scores (standard deviation) for follow-up visits. All data were analyzed as observed, with no imputation of missing data.

Results

483 patients (369 female, 114 male) were included in the study, with available baseline PRO information for 481 patients. 6-months follow-up data were yet available from 279 patients The baseline average age and disease duration were 58.0 (12.3) years and 9.0 (8.0) years, respectively, whereas the mean initial DAS28-CRP was 4.6 (1.0). At baseline, 60.8% of enrolled patients had previously been treated with biologic or targeted synthetic disease-modifying antirheumatic drugs. Overall, PRO scores improved from baseline throughout month 6 with a considerable amelioration at month 3, which was maintained at month 6. Responses were rapid, with improvement already evident at month 1 (Table 1). The NRS pain as a crucial PRO in RA confirmed the previously described pattern of results seen for most of the other PROs (Figure 1).

Table 1.

Baseline scores and average changes from baseline scores

NBaseline scores (SD)NChange from baseline - month 1 (SD)NChange from baseline - month 3 (SD)NChange from baseline - month 6(SD)Pain (NRS)4816.2 (2.2)393-2.2 (2.3)392-2.5 (2.5)258-2.4 (2.4)Fatigue (NRS)4815.5 (2.6)393-1.4 (2.3)393-1.6 (2.4)259-1.5 (2.3)HAQ-DI4711.3 (0.6)380-0.2 (0.3)376-0.2 (0.4)253-0.2 (0.4)Morning stiffness (duration, minutes)43968.9 (63.9)313-25.0 (55.3)296-29.6 (54.9)179-31.6 (51.7)Morning stiffness (severity)4785.2 (2.7)386-1.8 (2.3)393-2.2 (2.6)258-2.2 (2.9)PHQ-94778.7 (5.2)383-1.9 (3.9)381-2.3 (4.0)255-2.2 (3.8)RAID4815.6 (2.0)393-1.7 (1.8)392-2.0 (2.0)258-1.9 (1.9)

Conclusion

This interim analysis confirmed a meaningful improvement regarding included PROs that cover various RA-related symptoms, depressiveness and the impact of symptoms of RA on daily life.

References

[1]Smolen JS, et al. Lancet 2019;393:2303–11

[2]Burmester GR, et al. Lancet 2018;391:2503–12

[3]Genovese MC, et al. Lancet 2018;391:2513–24

[4]van Vollenhoven R, et al. Arthritis Rheumatol 2020;72:1607–20

[5]Fleischmann R, et al. Arthritis Rheumatol 2019;71:1788–800

[6]Rubbert-Roth A, et al. N Engl J Med 2020;383:1511–21

[7]Witte T et al. P0833 at ACR, Nov 5–9, 2021

Acknowledgements

AbbVie funded this study; contributed to its design; participated in data collection, analysis, and interpretation of the data; and in the writing, review, and approval of the abstract. AbbVie and the authors thank all study investigators for their contributions and the patients who participated in this study. No honoraria or payments were made for authorship. The medical writing support was provided by Matthias Englbrecht, Freelance Healthcare Data Scientist (Eckental, Germany) and was funded by AbbVie. Statistical analyses were provided by Dr. Daniela Adolf of StatConsult GmbH (Magdeburg, Germany) which was funded by AbbVie.

Disclosure of Interests

Torsten Witte Grant/research support from: AbbVie, Amgen, Bristol-Myers Squibb, Celgene, Chugai, Gilead, Janssen, Lilly, MSD, Mylan, Novartis, Pfizer, Roche, and UCB, Uta Kiltz Consultant of: AbbVie, Biocad, Eli Lilly and Company, Grünenthal, Hexal, Janssen, MSD, Novartis, Pfizer, Roche, and UCB, Grant/research support from: AbbVie, Amgen, Biogen, Fresenius, GSK, Hexal, Novartis, and Pfizer, Florian Haas Consultant of: AbbVie, Celgene, Novartis, and Pfizer, Grant/research support from: AbbVie, BMS, Celgene, Chugai, MSD, Novartis, Pfizer, Roche, and Sanofi Genzyme, Elke Riechers Consultant of: AbbVie, Chugai, Novartis, and UCB, Grant/research support from: AbbVie, Chugai, Lilly, Janssen, Novartis, Pfizer, Roche, and UCB, Ulrich Prothmann Grant/research support from: AbbVie, Amgen, Bristol-Myers Squibb, Chugai, Glaxo Smith Kline, Novartis, Pfizer, Roche, Sanofi, SOBI, and UCB, Daniela Adolf Shareholder of: Employee of StatConsult and may own stock or options, Employee of: Employee of StatConsult, Carsten Holland Shareholder of: Employee of AbbVie and may own stock or options, Employee of: Employee of AbbVie, Alexander Roessler Shareholder of: Employee of AbbVie and may own stock or options, Employee of: Employee of AbbVie, Kirsten Famulla Shareholder of: Employee of AbbVie and may own stock or options, Employee of: Employee of AbbVie, Konrad Götz Shareholder of: Employee of AbbVie and may own stock or options, Employee of: Employee of AbbVie, Klaus Krueger Grant/research support from: AbbVie, Biogen, BMS, Celltrion, Gilead, Hexal, Janssen, Lilly, Medac, MSD, Novartis, Pfizer, Roche, and UCB

Hemodynamic Responses in Lower Limb Lymphedema Patients Undergoing Physical Therapy

BACKGROUND

Lymphedema arises due to a malfunction of the lymphatic system, leading to extensive tissue swelling. Complete decongestive therapy (CDT), which is a physical therapy lasting for 3 weeks and includes manual lymphatic drainages (MLD), leads to fluid mobilization and increases in plasma volume. Here, we investigated hemodynamic responses induced by these fluid shifts due to CDT and MLD.

METHODS

Hemodynamic parameters were assessed continuously during a sit-to-stand test (5 min baseline, 5 min of standing, and 5 min of recovery). This intervention was repeated on days 1, 2, 7, 14, and 21 of CDT, before and after MLD. Volume regulatory hormones were assessed in plasma samples.

RESULTS

A total number of 13 patients took part in this investigation. Resting diastolic blood pressure significantly decreased over three weeks of CDT (p = 0.048). No changes in baseline values were shown due to MLD. However, MLD led to a significant decrease in heart rate during orthostatic loading over all epochs on therapy day 14, as well as day 21. Volume regulatory hormones did not show changes over lymphedema therapy.

CONCLUSION

We did not observe any signs of orthostatic hypotension at rest, as well as during to CDT, indicating that lymphedema patients do not display an elevated risk of orthostatic intolerance. Although baseline hemodynamics were not affected, MLD has shown to have potential beneficial effects on hemodynamic responses to a sit-to-stand test in patients undergoing lymphedema therapy.

AB0255 BASELINE CHARACTERISTICS OF PATIENTS WITH RHEUMATOID ARTHRITIS TREATED WITH UPADACITINIB IN GERMAN REAL-WORLD PRACTICE: RESULTS FROM THE POST-MARKETING OBSERVATIONAL UPwArds STUDY

Background:

The efficacy and safety of upadacitinib (UPA), a selective Janus kinase inhibitor, has been evaluated in the SELECT rheumatoid arthritis (RA) clinical program,1–6 but its real-world effectiveness remains to be investigated. The UPwArds study will assess the association of C-reactive protein (CRP) level with remission and other efficacy outcomes in patients with RA treated with UPA in German real-world practice.

Objectives:

To describe the baseline characteristics of patients enrolled in the UPwArds study.

Methods:

The prospective, open-label, multicenter, non-interventional, post-marketing UPwArds study included adult patients with moderate-to-severe RA (swollen joint count [SJC28] ≥3 and inadequate response or intolerance to ≥1 disease-modifying antirheumatic drug [DMARD]). Patients were treated with UPA 15 mg once daily, as monotherapy or in combination with methotrexate (MTX; 50:50 mono:combo enrollment planned), according to the German label. Variables assessed included medical history (disease duration, previous RA therapy, and vaccination status), CRP level, and disease activity (disease activity score [DAS28(CRP)], tender joint count [TJC28], and SJC28). There was no recruitment restriction regarding CRP level. This descriptive interim analysis reports patient baseline characteristics after enrollment was complete. All data were analyzed as observed, with no imputation of missing data.

Results:

533 patients (UPA monotherapy: 257 [48%]; UPA plus MTX: 276 [52%]) were included. Mean patient age was 58 years; mean disease duration was 9 years (Table 1). Despite having active RA, almost half the population (44%; n=237) did not have elevated CRP at the start of UPA treatment. Mean DAS28(CRP) was 4.6; mean TJC28 and SJC28 were 7.7 and 5.6, respectively. Overall, 39% of patients had not been treated with any biologic (b) DMARD or targeted synthetic (ts) DMARD before enrollment; 25% and 36% had previously been treated with 1 or ≥2 bDMARDs or tsDMARDs, respectively (Figure 1). 8.7% of patients had previously received a herpes zoster vaccination (8.1% Shingrix; 0.6% Zostavax).

Conclusion:

In German clinical practice, the population of patients with RA in the UPwArds study was predominantly treatment-refractory. Half of these patients had no elevated CRP despite active disease; future analyses will assess the impact of CRP on efficacy outcomes.

References:

[1]Smolen JS, et al. Lancet 2019;393:2303–11;

[2]Burmester GR, et al. Lancet 2018;391:2503–12;

[3]Genovese MC, et al. Lancet 2018;391:2513–24;

[4]van Vollenhoven R, et al. Arthritis Rheumatol 2020;72:1607–20;

[5]Fleischmann R, et al. Arthritis Rheumatol 2019;71:1788–800;

[6]Rubbert-Roth A, et al. N Engl J Med 2020;383:1511–21.

Table 1.

Baseline characteristics

Age, yearsUPAUPA + MTXTotal57.7 (13.2)n=25758.1 (11.4)n=27657.9 (12.3)n=533Disease duration, years9.4 (8.3)8.5 (7.7)9.0 (8.0)n=253n=272n=525CRP, mg/dL1.3 (1.9)1.1 (1.7)1.2 (1.8)n=257n=276n=533CRP >ULN, n (%)137 (53.3)159 (57.6)296 (55.5)n=257n=276n=533TJC287.4 (6.0)7.9 (6.4)7.7 (6.2)n=257n=276n=533SJC285.5 (3.7)5.6 (4.1)5.6 (3.9)n=257n=276n=533Patient’s Global Assessment6.2 (1.9)6.3 (1.8)6.3 (1.8)n=257n=276n=533Physician’s Global Assessment5.8 (1.5)5.9 (1.6)5.9 (1.6)n=257n=276n=533DAS28(CRP)4.6 (1.0)4.6 (1.0)4.6 (1.0)n=257n=276n=533DAS28(ESR)4.8 (1.1)4.9 (1.2)4.9 (1.1)n=224n=239n=463CDAI24.9 (10.2)25.7 (10.8)25.4 (10.5)n=257n=276n=533SDAI26.2 (10.5)26.9 (11.3)26.6 (10.9)n=257n=276n=533RAID5.7 (2.0)5.7 (2.0)5.7 (2.0)n=255n=275n=530Pain (RAID-1)6.2 (2.2)6.1 (2.3)6.2 (2.2)n=255n=275n=530SF-12 Physical Component Summary32.6 (8.5)33.9 (8.6)33.3 (8.6)n=245n=262n=507SF-12 Mental Component Summary42.4 (11.6)42.6 (11.3)42.5 (11.5)n=245n=262n=507HAQ-DI1.3 (0.7)1.3 (0.6)1.3 (0.6)n=250n=270n=520PHQ-98.9 (5.3)8.6 (5.3)8.7 (5.3)n=252n=272n=524Erosions, n (%)87 (33.9)95 (34.4)182 (34.1)n=257n=276n=533

Data are mean (SD), n unless otherwise stated

Acknowledgements:

AbbVie funded this study; contributed to its design; participated in data collection, analysis, and interpretation of the data; and in the writing, review, and approval of the abstract. AbbVie and the authors thank all study investigators for their contributions and the patients who participated in this study. No honoraria or payments were made for authorship. Medical writing support was provided by Grant Thomas Kirkpatrick, MSc, of 2 the Nth (Cheshire, UK), and was funded by AbbVie.

Disclosure of Interests:

Torsten Witte Grant/research support from: AbbVie, Amgen, Bristol-Myers Squibb, Celgene, Chugai, Gilead, Janssen, Lilly, MSD, Mylan, Novartis, Pfizer, Roche, and UCB., Uta Kiltz Consultant of: AbbVie, Biocad, Eli Lilly and Company, Grünenthal, Hexal, Janssen, MSD, Novartis, Pfizer, Roche, and UCB, Grant/research support from: AbbVie, Amgen, Biogen, Fresenius, GSK, Hexal, Novartis, and Pfizer, Florian Haas Consultant of: AbbVie, Celgene, Novartis, and Pfizer, Grant/research support from: AbbVie, BMS, Celgene, Chugai, MSD, Novartis, Pfizer, Roche, and Sanofi Genzyme, Elke Riechers Consultant of: AbbVie, Chugai, Novartis, and UCB, Grant/research support from: AbbVie, Chugai, Lilly, Janssen, Novartis, Pfizer, Roche, and UCB, Ulrich Prothmann Grant/research support from: AbbVie, Amgen, Bristol-Myers Squibb, Chugai, Glaxo Smith Kline, Novartis, Pfizer, Roche, Sanofi, SOBI, and UCB, Daniela Adolf Employee of: Employee of StatConsult and may own stock or options, Carsten Holland Employee of: Employee of AbbVie and may own stock or options, Rouven Hecht Employee of: Employee of AbbVie and may own stock or options, Alexander Roessler Employee of: Employee of AbbVie and may own stock or options, Kirsten Famulla Employee of: Employee of AbbVie and may own stock or options, Klaus Krueger Grant/research support from: AbbVie, Biogen, BMS, Celltrion, Gilead, Hexal, Janssen, Lilly, Medac, MSD, Novartis, Pfizer, Roche, and UCB.

Biology of Lymphedema

Simple Summary

Lymphedema is a chronic, debilitating disease of the lymphatic vasculature. Although several reviews focus on the anatomy and physiology of the lymphatic system, this review provides an overview of the lymphatic vasculature and, moreover, of lymphatic system dysfunction and lymphedema. Further, we aim at advancing the knowledge in the area of lymphatic system function and how dysfunction of the lymphatic system—as seen in lymphedema—affects physiological systems, such as the cardiovascular system, and how those might be modulated by lymphedema therapy.

Abstract

This narrative review portrays the lymphatic system, a poorly understood but important physiological system. While several reviews have been published that are related to the biology of the lymphatic system and lymphedema, the physiological alternations, which arise due to disturbances of this system, and during lymphedema therapy, are poorly understood and, consequently, not widely reported. We present an inclusive collection of evidence from the scientific literature reflecting important developments in lymphedema research over the last few decades. This review aims at advancing the knowledge on the area of lymphatic system function as well as how system dysfunction, as seen in lymphedema, affects physiological systems and how lymphedema therapy modulates these mechanisms. We propose that future studies should aim at investigating, in-detail, aspects that are related to fluid regulation, hemodynamic responses, and endothelial and/or vascular changes due to lymphedema and lymphedema therapy.

PHYSICAL THERAPY AFFECTS ENDOTHELIAL FUNCTION IN LYMPHEDEMA PATIENTS

Lymphedema arises due to a malfunction of the lymphatic system and can lead to massive tissue swelling. Complete decongestive therapy (CDT), consisting of manual lymphatic drainage (MLD) and compression bandaging, is aimed at mobilizing fluid and reducing volume in affected extremities. Lymphatic dysfunction has previously been associated with chronic inflammation processes. We investigated plasma ADMA as an indicator of endothelial function/inflammation before-, during- and after-CDT. Also assessed were vascular function parameters such as carotid-femoral pulse wave velocity (PWVcf), flow-mediated dilatation (FMD) and retinal microvasculature analysis. 13 patients (3 males and 10 females, 57 ± 8 years old (mean ± SD), 167.2 ± 8.3 cm height, 91.0 ± 23.5 kg weight), with lower limb lymphedema were included. Vascular function parameters were assessed on day 1, 2, 7, 14 and 21 of CDT, pre- and post-MLD. ADMA was significantly lower post-MLD (p=0.0064) and tended to reduce over three weeks of therapy (p=0.0506). PWVcf weakly correlated with FMD (r=0.361, p=0.010). PWVcf, FMD and retinal microvasculature analysis did not show changes due to physical therapy. The novel results from this study indicate that lymphedema does not affect endothelial function and lymphedema patients may therefore not have a higher risk of cardiovascular diseases. Our results further suggest that manual lymphatic drainage with or without full CDT could have potentially beneficial effects on endothelial function in lymphedema patients (by reducing ADMA levels), which has not been reported previously.

Menstrual Phase Affects Coagulation and Hematological Parameters during Central Hypovolemia

Background: It has been reported that women have a higher number of heart attacks in the “follicular phase” of the menstrual cycle. We, therefore, tested the hypothesis that women in the follicular phase exhibit higher coagulability. As lower body negative pressure (LBNP) has been used previously to assess coagulation changes in whole blood (WB) samples in men and women, effects of menstrual phase on coagulation was assessed during LBNP. Methods: Seven women, all healthy young participants, with no histories of thrombotic disorders and not on medications, were tested in two phases of the menstrual cycle (early follicular (EF) and mid-luteal (ML)). LBNP was commenced at −10 mmHg and increased by −10 mmHg every 5 min until a maximum of −40 mmHg. Recovery up to 10 min was also monitored. Blood samples were collected at baseline, at end of LBNP, and at end of recovery. Hemostatic profiling included comparing the effects of LBNP on coagulation values in both phases of the menstrual cycle using standard coagulation tests, calibrated automated thrombogram, thrombelastometry, impedance aggregometry, and markers of thrombin formation. Results: LBNP led to coagulation activation determined in both plasma and WB samples. During both phases, coagulation was affected during LBNP, as reflected in their decreased partial thromboplastin time (PTT) and elevated coagulation factor VIII FVIII, F1 + 2, and thrombin-antithrombin (TAT) levels. Additionally, during the ML phase, greater PT [%] and shorter time to peak (ttPeak) values (implying faster maximum thrombin formation) suggest that women in the ML phase are relatively hypercoagulable compared to the early follicular phase. Conclusions: These results suggest that thrombosis occurs more during the midluteal phase, a finding with substantial medical implications.

Physical therapy affects endothelial function in lymphedema patients

Lymphedema arises due to a malfunction of the lymphatic system and can lead to massive tissue swelling. Complete decongestive therapy (CDT), consisting of manual lymphatic drainage (MLD) and compression bandaging, is aimed at mobilizing fluid and reducing volume in affected extremities. Lymphatic dysfunction has previously been associated with chronic inflammation processes. We investigated plasma ADMA as an indicator of endothelial function/inflammation before-, during- and after-CDT. Also assessed were vascular function parameters such as carotid-femoral pulse wave velocity (PWVcf), flow-mediated dilata-tion (FMD) and retinal microvasculature analysis. 13 patients (3 males and 10 females, 57 ± 8 years old (mean ± SD), 167.2 ± 8.3 cm height, 91.0 ± 23.5 kg weight), with lower limb lymphedema were included. Vascular function parameters were assessed on day 1, 2, 7, 14 and 21 of CDT, pre- and post-MLD. ADMA was significantly lower post-MLD (p=0.0064) and tended to reduce over three weeks of therapy (p=0.0506). PWVcf weakly correlated with FMD (r=0.361, p=0.010). PWVcf, FMD and retinal microvasculature analysis did not show changes due to physical therapy. The novel results from this study indicate that lymphedema does not affect endothelial func-tion and lymphedema patients may therefore not have a higher risk of cardiovas-cular diseases. Our results further suggest that manual lymphatic drainage with or without full CDT could have potentially beneficial effects on endothelial function in lymphedema patients (by reducing ADMA levels), which has not been reported previously.

Sex differences in cardiovascular responses to orthostatic challenge in healthy older persons: A pilot study

Background

Premenopausal women show a higher incidence of orthostatic hypotension than age-matched men, but there are limited data available on sex differences in cardiovascular responses to orthostatic challenge in healthy older persons. We investigated sex differences in hemodynamic and autonomic responses to orthostatic challenge in healthy older males and females.

Materials and methods

Fourteen older healthy women and 10 age-matched men performed a sit-to-stand test (5 min of sitting followed by 5 min of standing). A Task Force® Monitor continuously measured the following beat-to-beat hemodynamic parameters: heart rate, systolic blood pressure, diastolic blood pressure, mean blood pressure, stroke index, cardiac index, and total peripheral resistance index. Cardiac autonomic activity, low-frequency (LF: 0.04–0.15 Hz) normalized (LFnuRRI) and high-frequency (HF: 0.15–0.4 Hz) normalized (HFnuRRI) components, and the ratio between LF and HF power (LF/HF) were calculated using power spectral analysis of heart rate variability.

Results

Across all hemodynamic parameters, there were no significant differences between the sexes at baseline and during standing. LFnuRRI (median: 70.2 vs. 52.3, p < 0.05) and LF/HF ratio (median: 2.4 vs. 1.1, p < 0.05) were significantly higher, whereas HFnuRRI (median: 29.8 vs. 47.7, p < 0.05) was lower among women at baseline. All other heart rate variability measures did not differ between the sexes.

Conclusions

The data indicate that older women showed higher sympathetic and lower parasympathetic activity at rest compared to age-matched men. These results are contradictory to the observations from previous studies, which showed a reduced sympathetic and enhanced parasympathetic activity in women in all ages. Further studies are required to determine the underlying mechanisms contributing to higher incidence of orthostatic hypotension in older females.

Psychophysiological concomitants of burnout: Evidence for different subtypes

BACKGROUND

There is evidence that chronic stress and emotional exhaustion are related to physiological dysregulations, which could negatively impact physical and mental health. This study aimed to identify the specific physiological clusters which are most reliable and prominently associated with burnout. Emphasis was placed on variables of the autonomic nervous system and hypothalamic-pituitary-adrenal axis. Burnout was assessed using the Emotional Exhaustion subscale of the German version of the Maslach Burnout Inventory (MBI-GS).

METHODS

A sample of 105 individuals aged between 28 and 60 years (M = 42.7, SD = 7.75) and working under highly demanding conditions participated in this study. 46 participants reported a low risk of burnout, and 58 participants a high risk. They underwent 24 h of ECG monitoring, had cortisol awakening response collected, and had blood pressure measured two times within a week.

RESULTS

Compromised HRV, higher cortisol values, and higher blood pressure were found in individuals with high burnout symptoms. Furthermore, a discriminant function analysis on cardiac and neuroendocrine variables suggested two subgroups within the high burnout individuals, with only one group showing evidence for autonomic dysfunction as indicated by lower vagal efference.

CONCLUSIONS

Results suggest that burnout might not necessarily imply physiological disturbances, thus calling for a more differentiated and individualized view of burnout.

Galanin and Adrenomedullin Plasma Responses During Artificial Gravity on a Human Short-Arm Centrifuge

Galanin and adrenomedullin plasma responses to head-up tilt and lower body negative pressure have been studied previously. However, to what extent short-arm human centrifugation (SAHC) affects these responses is not known. In this study, we assessed how the application of variable gradients of accelerations (ΔGz ) via shifting of the rotation axis during centrifugation affects selected hormonal responses. Specifically, we tested the hypothesis, that cardiovascular modulating hormones such as galanin and adrenomedullin will be higher in non-finishers (participants in whom at least one of the pre-defined criteria for presyncope was fulfilled) when compared to finishers (participants who completed the entire protocol in both sessions) during SAHC exposure. Twenty healthy subjects (10 women and 10 men) were exposed to two g-levels [1 Gz and 2.4 Gz at the feet (Gz_Feet)] in two positions (axis of rotation placed above the head and axis of rotation placed at the heart level). Elevated baseline levels of galanin appeared to predict orthostatic tolerance (p = 0.054) and seemed to support good orthostatic tolerance during 1 Gz_Feet SAHC (p = 0.034). In finishers, 2.4 Gz_Feet SAHC was associated with increased galanin levels after centrifugation (p = 0.007). For adrenomedullin, the hypothesized increases were observed after centrifugation at 1 Gz_Feet (p = 0.031), but not at 2.4 Gz_Feet, suggesting that other central mechanisms than local distribution of adrenomedullin predominate when coping with central hypovolemia induced by SAHC (p > 0.14). In conclusion, baseline galanin levels could potentially be used to predict development of presyncope in subjects. Furthermore, galanin levels increase during elevated levels of central hypovolemia and galanin responses appear to be important for coping with such challenges. Adrenomedullin release depends on degree of central hypovolemia induced fluid shifts and a subject's ability to cope with such challenges. Our results suggest that the gradient of acceleration (ΔGz ) is an innovative approach to quantify the grade of central hypovolemia and to assess neurohormonal responses in those that can tolerate (finishers) or not tolerate (non-finishers) artificial gravity (AG). As AG is being considered as a preventing tool for spaceflight induced deconditioning in future missions, understanding effects of AG on hormonal responses in subjects who develop presyncope is important.

Heart rate variability and baroreceptor reflex sensitivity in early- versus late-onset preeclampsia

OBJECTIVE

To determine whether there are differences in autonomic nervous system function in early- versus late-onset preeclampsia.

METHODS

Matched case-control study. Cases were defined as singleton pregnancies with preeclampsia at < 34+0 weeks of gestation (early-onset preeclampsia) and ≥ 34+0 weeks of gestation (late-onset preeclampsia). For each case in each of the preeclampsia subgroups, three "control"uncomplicated singleton pregnancies were matched by maternal age, height, and week of gestation. Blood pressure and heart rate were measured continuously for 30 minutes in each participant. Baroreceptor reflex sensitivity (assessed using sequence technique), time and frequency domain heart rate variability measures, as SDNN, RMSSD, LFRRI, HFRRI and LF/HFRRI of R-R intervals, were compared between groups (p<0.05 significant).

RESULTS

24 women with preeclampsia (10 with early-onset and 14 with late-onset preeclampsia) and 72 controls were included in the study. SDNN, RMSSD and HFRRI were significantly higher in the late-onset preeclampsia group compared to gestational age matched controls (p = 0.033, p = 0.002 and p = 0.018, respectively). No significant differences in SDNN RMSSD and HFRRI between early-onset preeclampsia group and gestational age matched controls were observed (p = 0.304, p = 0.325 and p = 0.824, respectively). Similarly, baroreceptor reflex sensitivity was higher in late-onset preeclampsia compared to controls at ≥ 34 weeks (p = 0.037), but not different between early-onset preeclampsia compared to controls at < 34 weeks (p = 0.50).

CONCLUSIONS

Heart rate variability and baroreceptor reflex sensitivity are increased in late- but not early-onset preeclampsia compared to healthy pregnancies. This indicates a better autonomic nervous system mediated adaptation to preeclampsia related cardiovascular changes in late-onset disease.

Existence of bovine neonatal pancytopenia before the year 2005? Retrospective evaluation of 215 cases of haemorrhagic diathesis in cattle

Haemorrhagic diathesis (HD) in cattle is a relatively rare syndrome that can have many different causes. With the occurrence of bovine neonatal pancytopenia (BNP) in 2007, the number of cases of HD in cattle has increased. This led to an enhanced interest in diseases presenting with bleeding disorders. The possible causes of HD in cattle, the clinical findings, and the course of various diseases are described and evaluated. Furthermore, we determined whether cases of BNP occurred before the introduction of the vaccine Pregsure BVD since its widespread use was associated with the syndrome. Records of 215 cases of HD in cattle that had been referred to the Clinic for Ruminants with Ambulatory and Herd Health Services at the Centre for Clinical Veterinary Medicine, Ludwig Maximilian University, Munich, between 1982 and 2014 were evaluated. The two most commonly diagnosed diseases were BNP (n = 95) and septicaemia (n = 35), with fatality rates of 82% and 66%, respectively. In 27 (13%) cases, no clear cause for the HD could be designated. Statistically significant differences were found with regard to the course of the various disorders and the clinical findings. A receiver operating characteristic analysis of thrombocyte counts of affected animals at the time of arrival at the clinic did not provide any predictive information on disease outcome. Two cases of HD occurred before the introduction of Pregsure BVD (1989, 1991). In both cases, clinical, haematological, and pathological findings were identical to BNP. The cause of HD in these two cases could not be determined retrospectively.

Effect of orthostasis on endothelial function: a gender comparative study

As the vascular endothelium has multiple functions, including regulation of vascular tone, it may play a role in the pathophysiology of orthostatic intolerance. We investigated the effect of orthostasis on endothelial function using EndoPAT®, a non-invasive and user-independent method, and across gender. As sex steroid hormones are known to affect endothelial function, this study examined the potential effect of these hormones on the endothelial response to orthostasis by including females at different phases of the menstrual cycle (follicular and luteal—where the hormone balance differs), and females taking an oral contraceptive. A total of 31 subjects took part in this study (11 males, 11 females having normal menstrual cycles and 9 females taking oral contraceptive). Each subject made two visits for testing; in the case of females having normal menstrual cycles the first session was conducted either 1–7 (follicular) or 14–21 days (luteal) after the start of menstruation, and the second session two weeks later, i.e., during the other phase, respectively. Endothelial function was assessed at baseline and following a 20-min orthostatic challenge (active standing). The EndoPAT® index increased from 1.71 ± 0.09 (mean ± SEM) at baseline to 2.07 ± 0.09 following orthostasis in females (p<0.001). In males, the index increased from 1.60 ± 0.08 to 1.94 ± 0.13 following orthostasis (p<0.001). There were no significant differences, however, in the endothelial response to orthostasis between females and males, menstrual cycle phases and the usage of oral contraceptive. Our results suggest an increased vasodilatatory endothelial response following orthostasis in both females and males. The effect of gender and sex hormones on the endothelial response to orthostasis appears limited. Further studies are needed to determine the potential role of this post orthostasis endothelial response in the pathophysiology of orthostatic intolerance.

Phase synchronization of hemodynamic variables at rest and after deep breathing measured during the course of pregnancy

Background

The autonomic nervous system plays a central role in the functioning of systems critical for the homeostasis maintenance. However, its role in the cardiovascular adaptation to pregnancy-related demands is poorly understood. We explored the maternal cardiovascular systems throughout pregnancy to quantify pregnancy-related autonomic nervous system adaptations.

Methodology

Continuous monitoring of heart rate (R-R interval; derived from the 3-lead electrocardiography), blood pressure, and thoracic impedance was carried out in thirty-six women at six time-points throughout pregnancy. In order to quantify in addition to the longitudinal effects on baseline levels throughout gestation the immediate adaptive heart rate and blood pressure changes at each time point, a simple reflex test, deep breathing, was applied. Consequently, heart rate variability and blood pressure variability in the low (LF) and high (HF) frequency range, respiration and baroreceptor sensitivity were analyzed in resting conditions and after deep breathing. The adjustment of the rhythms of the R-R interval, blood pressure and respiration partitioned for the sympathetic and the parasympathetic branch of the autonomic nervous system were quantified by the phase synchronization index γ, which has been adopted from the analysis of weakly coupled chaotic oscillators.

Results

Heart rate and LF/HF ratio increased throughout pregnancy and these effects were accompanied by a continuous loss of baroreceptor sensitivity. The increases in heart rate and LF/HF ratio levels were associated with an increasing decline in the ability to flexibly respond to additional demands (i.e., diminished adaptive responses to deep breathing). The phase synchronization index γ showed that the observed effects could be explained by a decreased coupling of respiration and the cardiovascular system (HF components of heart rate and blood pressure).

Conclusions/Significance

The findings suggest that during the course of pregnancy the individual systems become increasingly independent to meet the increasing demands placed on the maternal cardiovascular and respiratory system.

Coagulation changes during presyncope and recovery

Orthostatic stress activates the coagulation system. The extent of coagulation activation with full orthostatic load leading to presyncope is unknown. We examined in 7 healthy males whether presyncope, using a combination of head up tilt (HUT) and lower body negative pressure (LBNP), leads to coagulation changes as well as in the return to baseline during recovery. Coagulation responses (whole blood thrombelastometry, whole blood platelet aggregation, endogenous thrombin potential, markers of endothelial activation and thrombin generation), blood cell counts and plasma mass density (for volume changes) were measured before, during, and 20 min after the orthostatic stress. Maximum orthostatic load led to a 25% plasma volume loss. Blood cell counts, prothrombin levels, thrombin peak, endogenous thrombin potential, and tissue factor pathway inhibitor levels increased during the protocol, commensurable with hemoconcentration. The markers of endothelial activation (tissue factor, tissue plasminogen activator), and thrombin generation (F1+2, prothrombin fragments 1 and 2, and TAT, thrombin-antithrombin complex) increased to an extent far beyond the hemoconcentration effect. During recovery, the markers of endothelial activation returned to initial supine values, but F1+2 and TAT remained elevated, suggestive of increased coagulability. Our findings of increased coagulability at 20 min of recovery from presyncope may have greater clinical significance than short-term procoagulant changes observed during standing. While our experiments were conducted in healthy subjects, the observed hypercoagulability during graded orthostatic challenge, at presyncope and in recovery may be an important risk factor particularly for patients already at high risk for thromboembolic events (e.g. those with coronary heart disease, atherosclerosis or hypertensives).

Delaying orthostatic syncope with mental challenge: a pilot study

At orthostatic vasovagal syncope there appears to be a sudden decline of sympathetic activity. As mental challenge activates the sympathetic system, we hypothesized that doing mental arithmetic in volunteers driven to the end point of their cardiovascular stability may delay the onset of orthostatic syncope. We investigated this in healthy male subjects. Each subject underwent a head up tilt (HUT)+ graded lower body negative pressure (LBNP) up to presyncope session (control) to determine the orthostatic tolerance time, OTT (Time from HUT commencement to development of presyncopal symptoms/signs). Once the tolerance time was known, a randomized crossover protocol was used: either 1) Repeat HUT+LBNP to ensure reproducibility of repeated run or 2) HUT+LBNP run but with added mental challenge (2 min before the expected presyncope time). Test protocols were separated by 2 weeks. Our studies on five male test subjects indicate that mental challenge improves orthostatic tolerance significantly. Additional mental loading could be a useful countermeasure to alleviate the orthostatic responses of persons, particularly in those with histories of dizziness on standing up, or to alleviate hypotension that frequently occurs during hemodialysis or on return to earth from the spaceflight environment of microgravity.

The effect of probiotics on faecal microbiota and genotoxic activity of faecal water in patients with atopic dermatitis: a randomized, placebo-controlled study

BACKGROUND

Colonic microbiota is involved in the etiology of colon cancer according to several reports. Studies also indicate that the microbiota differs between atopic patients and healthy subjects.

OBJECTIVE

To evaluate whether a probiotic mix containing Lactobacillus paracasei Lpc-37, Lactobacillus acidophilus 74-2, and Bifidobacterium animalis subsp. lactis DGCC 420 can affect the microbiota and its genotoxic activity in healthy subjects and patients with atopic dermatitis (AD).

METHODS

A placebo-controlled cross-over study was conducted. Fifteen healthy adults and 15 adult AD patients consumed 2×100 ml/d of either a probiotic or a placebo drink for 8 weeks followed by a wash out period of 2 weeks before crossing the intervention. Faecal water was isolated from stool samples collected at the end of each period. HT29c19a cells incubated with faecal water were measured for DNA damage using single-cell gel electrophoresis ("comet assay"). Bacterial species were determined by qPCR and concentrations of short-chain fatty acids were measured by means of gas chromatography.

RESULTS

Probiotic supplementation resulted in a significant increase in lactobacilli, whereas numbers of Bifidobacteria and Bacteroidetes remained unchanged. Clostridium perfringens cluster I-II was significantly reduced in healthy subjects. Genotoxic potential (expressed as tail intensity) of faecal water, was not affected. However, tail intensity decreased significantly in the probiotic period compared to placebo (23.5 vs. 16.7%) in AD patients. Although faecal concentrations of short-chain fatty acids were not affected, faecal pH was significantly reduced (7.0 vs. 6.6) in AD patients after probiotics.

CONCLUSION

The results indicate that probiotics lower the genotoxic potential of faecal water in AD patients. The faecal C. perfringens cluster I-II levels remained unaffected suggesting either a change in their activity, or the fact that other bacterial species are responsible for the reduced genotoxic activity of faecal water.

Volume regulating hormone responses to repeated head-up tilt and lower body negative pressure

BACKGROUND

We hypothesized the existence of different hormonal response patterns to repeated lower body negative pressure (LBNP) and head-up tilt (HUT) in healthy males. We compared hormonal, cardiovascular and plasma volume changes from rest to stress within- and between-LBNP and HUT applications. Hormones investigated included adrenocorticotropic hormone (ACTH), aldosterone, plasma renin activity (PRA), atrial natriuretic peptide (ANP) and arginine vasopressin (AVP).

MATERIALS AND METHODS

Three sequential 30-min bouts of LBNP at -55mmHg (n=14) or 70° HUT (n=9) were preceded by 30-min supine rest, and a 60-min supine rest followed the 3rd stimulus.

RESULTS

Plasma renin activity increases above baseline, in relation to aldosterone, were larger with LBNP than with HUT. The 3rd HUT application resulted in a greater increase in aldosterone compared to LBNP. Mean arterial blood pressure was elevated significantly during 1st and 3rd HUT application. ACTH responses were highly correlated with those of aldosterone in both LBNP and HUT (r(2) =0·96). AVP responses, in contrast to ANP, to the three consecutive stress situations were not significantly different, both with LBNP and HUT.

CONCLUSIONS

We speculate that the observed differences in blood pressure and hormonal responses to LBNP and HUT are caused by divergent effects of blood pooling in the splanchnic region, despite similar reductions in splanchnic perfusion. Apparently with repeated central hypovolaemia, especially by the 3rd application of stress, plasma aldosterone levels rise (along with ACTH), conceivably increasing its volume-guarding effect.

Modulation of plasma adrenomedullin by epinephrine infusion during head up tilt

We investigated whether head up tilt (HUT) with and without simultaneous epinephrine infusion modulate plasma adrenomedullin. We studied eight healthy male volunteers, using two 5 min 70° HUT trials: control (saline infusion) and intervention (epinephrine infusion, titrated to a dose which increased supine systolic pressure by 20% above resting values). Protocols were randomized and separated by 2 weeks. Cardiac function and systolic time intervals, recorded using a phonocardiograph microphone, included left ventricular ejection time (LVET), pre-ejection period (PEP), PEP/LVET and electromechanical systole (QS2). Compared to saline infusion, epinephrine increased supine adrenomedullin (3.2 ± 0.8 pmol/l, i.e., mean ± SEM, respectively), heart rate (HR) (+11.3 ± 2.6 bpm), systolic pressure (+18.4 ± 2.6 mmHg) but decreased supine LVET, LVET corrected for HR (LVETi) and QS2-time (all p = 0.004). Despite similar HUT induced thoracic fluid shifts, reflected by similar thoracic impedance changes, HUT-induced adrenomedullin increases were minimal in epinephrine-supplemented men in comparison to controls (+8% vs. 42%). During HUT, epinephrine infusion decreased only the LVET (p = 0.039). Our findings confirm that short-term HUT increases plasma adrenomedullin. They further suggest that with increased supine epinephrine levels (epinephrine infusion clamping systolic arterial pressure at 120% control level), supine cardiac performance rises to a level similar to that during HUT, while adrenomedullin is still elevated with HUT. This might be in accordance with a 'dampening' role of adrenomedullin during catecholaminergic cardiovascular stimulation. As epinephrine is used as a drug to treat cardiac arrest and ventricular arrhythmias, our results may have important clinical/emergency resuscitation applications.

Phase synchronization of hemodynamic variables and respiration during mental challenge

We studied the synchronization of heart rate, blood pressure and respiration in the sympathetic and parasympathetic branches of the autonomic nervous system during a cancellation test of attention and during mental arithmetic tasks. The synchronization was quantified by the index γ, which has been adopted from the analysis of weakly coupled chaotic oscillators. We analyzed in twenty healthy women the continuous signals partitioned in low (LF, 0.04-0.15 Hz) and high (HF, 0.15-0.40 Hz) frequencies to investigate whether or not respiration is a main determinant of cardiovascular synchronization. We used surrogate data analysis to distinguish between causal relationships from those that occur by chance. The LF-components of R-R interval and blood pressure showed no synchronization with respiration, whereas synchronization between blood pressure and R-R interval exceeded that occurring by chance (p < .001). Although heart rate, blood pressure and respiratory frequency increased from rest to mental challenge, no effect of mental challenge on the synchronization of the LF-components was seen. The HF-components showed significant synchronization for all variables (p < .001). During mental challenge, synchronization between respiration and R-R interval, respiration and systolic blood pressure (SBP), as well as R-R interval and SBP decreased (p < .01), whereas under resting conditions, respiration was one of the dominant mechanisms determining heart rate variability and systolic blood pressure fluctuations. We conclude that the observed decrease of synchronization during mental challenge is not only driven by the increase in respiratory frequency but that 'top down' intervention by the control system at higher levels may play an additional role.

The cardiovascular response to lower body negative pressure in humans depends on seal location

We tested whether seal location at iliac crest (IC) or upper abdomen (UA), before and during lower body negative pressure (LBNP), would affect thoracic electrical impedance, hepatic blood flow, and central cardiovascular responses to LBNP. After 30 min of supine rest, LBNP at -40 mm Hg was applied for 15 min, either at IC or UA, in 14 healthy males. Plasma density and indocyanine green concentrations assessed plasma volume changes and hepatic perfusion. With both sealing types, LBNP-induced effects remained unchanged for mean arterial pressure (-3.0+/-1.1 mm Hg), cardiac output (-1.0 l min(-1)), and plasma volume (-11 %). Heart rate was greater during UA (80.6+/-3.3 bpm) than IC (76.0+/-2.5 bpm) (p<0.01) and thoracic impedance increased more using UA (3.2+/-0.2 Omega) than IC (1.8+/-0.2 Omega) (p<0.0001). Furthermore, during supine rest, UA was accompanied by lower thoracic impedance (26.9+/-1.1 vs 29.0+/-0.8 Omega, p<0.001) and hepatic perfusion (1.6 vs 1.8 l.min(-1), p<0.05) compared to IC. The data suggest that the reduction in central blood volume in response to LBNP depends on location of the applied seal. The sealing in itself altered blood volume distribution and hepatic perfusion in supine resting humans. Finally, application of LBNP with the seal at the upper abdomen induced a markedly larger reduction in central blood volume and greater increases in heart rate than when the seal was located at the iliac crest.

The immune system in healthy adults and patients with atopic dermatitis seems to be affected differently by a probiotic intervention

BACKGROUND

Probiotic bacteria are proposed to alleviate atopic dermatitis (AD) in infants. There are few indications about the effect of probiotics on AD in adults.

OBJECTIVE

The purpose of this study was to elucidate the influence of a probiotic drink containing a combination of the probiotics Lactobacillus paracasei Lpc-37, Lactobacillus acidophilus 74-2 and Bifidobacterium animalis subsp. lactis DGCC 420 (B. lactis 420) in healthy volunteers and in patients with AD on clinical and immunological parameters and their detection in feces.

METHODS

A double-blind, placebo-controlled, randomized cross-over study was conducted in 15 healthy adults and 15 patients with AD. The probiotic product or placebo was given over 8 weeks. A 2-week washout period was interconnected before the intervention was crossed. At the end of each period, blood and stool samples were collected. In patients, the severity of AD was evaluated using the Scoring of Atopic Dermatitis (SCORAD).

RESULTS

L. paracasei and B. lactis were recovered in high numbers in feces after supplementation, whereas L. acidophilus marginally increased. In patients, the SCORAD tended to decrease by 15.5% (P=0.081). Major lymphocyte subsets were not affected by the probiotic intervention. However, CD57(+) increased significantly (P=0.034) in healthy subjects after probiotic intake and was not changed in patients, whereas CD4(+)CD54(+) decreased significantly (P=0.031) in patients with AD and remained uninfluenced in healthy subjects. The expression of CD4(+)CD25(+) T cells was similar in healthy subjects and AD patients. The phagocytic activity of monocytes and granulocytes was significantly increased in healthy subjects after probiotic intervention (P=0.014).

CONCLUSION

L. paracasei Lpc-37 and B. lactis 420 are able to colonize the intestine transiently. This study reveals that the probiotics differently modulate peripheral immune parameters in healthy subjects and patients with AD.

Renal adrenomedullin and high altitude diuresis

Previous investigations revealed that most of the fluid regulating hormones showed no consistent relationship to the hypoxic diuretic response (HDR). In this study we examined if adrenomedullin (AM), a hypoxia-mediated diuretic/natriuretic peptide is connected to HDR. Thirty-three persons were examined at low altitude (LA), on the third exposure day at 3440 m (medium altitude, MA) and on the fourteenth day at 5050 m (high altitude, HA). Nocturnal diuresis rose from 460 ml [interquartile range 302 ml] at LA to 560 [660] ml at MA to 1015 [750] ml at HA (p<0.005). Sodium excretion was similar at LA and MA (41.8 [27.0] vs. 41.4 [28.4] mM) and increased to 80.2 [29.1] mM at HA (p<0.005). Urinary AM excretion was 7.9 [3.9] at LA, 7.5 [5.7] pM at MA, and increased to 10.5 [5.1] pM (p<0.05) at HA. Urinary AM excretion was correlated to diuresis (r=0.72, p<0.005) and sodium excretion (r=0.57, p<0.005). Plasma AM concentration rose from 16.4 [3.1] to 18.8 [4.9] pM/l at MA (p<0.005) and to 18.3 [4.3] pM/l at HA (p<0.005). Plasma AM concentration and urinary AM excretion were not correlated, neither were plasma AM concentration and diuresis or natriuresis. Our data suggest the involvement of increased renal AM production in the pathophysiology of high altitude fluid and sodium loss.

Aspirin resistance in secondary stroke prevention

BACKGROUND

We investigated the platelet function in stroke patients treated with aspirin [acetylsalicylic acid (ASA)] for secondary stroke prevention during a follow-up period of 1 year.

METHODS

In this prospective study 291 patients with first initiated aspirin therapy (300 mg/day) for secondary stroke prevention were included. Platelet aggregation measurements were performed 24 h, 3, 6, and 12 months after starting medication.

RESULTS

Twenty-one of 291 patients (7.2%) were identified as primary ASA-non-responders (initial insufficient platelet inhibition) and 4.1% as secondary ASA-non-responders (insufficient platelet inhibition during follow-up). There were no significant differences between ASA-responders and ASA-non-responders concerning age, gender, risk factors, and stroke characteristics.

CONCLUSION

Aspirin resistance in stroke patients is not uncommon. The clinical usefulness of routine platelet function tests needs to be proved by further trials.

Role of Hypobaria in Fluid Balance Response to Hypoxia

To estimate the separate and combined effects of reduced P(B) and O2 levels on body fluid balance and regulating hormones, measurements were made during reduced PB (altitude, ALT; P(B) = 432 mm Hg, F(I(O2)) = 0.207), reduced inspired O2 concentration (normobaric hypoxia, HYX; P(B) = 614 mm Hg, F(I(O2)) = 0.142), and lowered ambient pressure without hypoxia (normoxic hypobaria HYB; P(B) = 434 mm Hg, F(I(O2)) = 0.296). Nine fit and healthy young men were exposed to these conditions for 10 h in a decompression chamber. Lake Louise AMS scores, urine collections, and blood samples were obtained every 3 h, with recovery measurements 2 h after exposure. AMS was significantly greater during ALT than HYX, as previously reported (J. Appl. Physiol. 81:1908-1910. 1996), because the combination of reduced P(B) and P(O2) over the 10 h favored fluid retention by reducing urine volume, while plasma volume (PV) remained higher than during HYX. At ALT the plasma Na+ fell significantly at 6 h, probably from dilution of extracellular fluid, and antidiuretic hormone (ADH) was highest (p = 0.006 versus HYB). The PV, urine flow, free water clearance, and plasma renin activity (PRA) rose significantly during recovery from ALT as AMS symptoms subsided, suggesting increased intravascular fluid and reduced adrenergic tone. During HYB, the plasma aldosterone (ALDO) and K+ levels were significantly elevated, and PRA was highest and ADH lowest, without fluid retention. During HYX, fluid balance was similar to HYB, but PV and ALDO were significantly lower, and ALDO increased significantly in recovery from HYX. The fluid retention at ALT in AMS-susceptible subjects appears related to a synergistic interaction involving reduced P(B) and ADH and ALDO.

Immersive virtual environments in cue exposure

Cue reactivity to drug-related stimuli is a frequently observed phenomenon in drug addiction. Cue reactivity refers to a classical conditioned response pattern that occurs when an addicted subject is exposed to drug-related stimuli. This response consists of physiological and cognitive reactions. Craving, a subjective desire to use the drug of choice, is believed to play an important role in the occurrence of relapse in the natural setting. Besides craving, other subjective cue-elicited reactions have been reported, including withdrawal symptoms, drug-agonistic effects, and mood swings. Physiological reactions that have been investigated include skin conductance, heart rate, salivation, and body temperature. Conditioned reactivity to cues is an important factor in addiction to alcohol, nicotine, opiates, and cocaine. Cue exposure treatment (CET) refers to a manualized, repeated exposure to drug-related cues, aimed at the reduction of cue reactivity by extinction. In CET, different stimuli are presented, for example, slides, video tapes, pictures, or paraphernalia in nonrealistic, experimental settings. Most often assessments consist in subjective ratings by craving scales. Our pilot study will show that immersive virtual reality (IVR) is as good or even better in eliciting subjective and physiological craving symptoms as classical devices.

Diversity among hospice volunteers: a challenge for the development of a responsive volunteer program

Voluntary organizations such as hospices are increasingly being called upon to substitute for state health and social welfare delivery at a time when volunteer contributions are threatened because of organizational and demographic changes. These changes include: the adoption by the nonprofit sector of market strategies in response to health and social welfare reforms, increases in the size and complexity of hospices, increasing professionalization of staff, and the move of women away from voluntary work in the health and welfare services to paid employment. With these changes, hospices must be knowledgeable about their volunteer workforce and resourceful if they are to continue to attract and retain volunteers. A survey of volunteers conducted at the Mary Potter Hospice, Wellington, New Zealand, examined differences in volunteers' characteristics, motivations for joining hospice, and factors affecting work satisfaction according to age, gender, and the length of time volunteers had worked. Those findings of particular relevance to program development were: (1) the tendency for the recently recruited volunteers to be in paid employment; (2) the mixed motivations of the younger volunteers, reflecting both altruistic and personal gain needs; and (3) the rewards commonly identified by volunteers, such as feeling their work is of value, being accepted by hospice staff, and feeling like important team members. Practical outcomes of the study are described.

From toy to tool: the development of immersive virtual reality environments for psychotherapy of specific phobias

Virtual Reality (VR) entered the mental health field some years ago. While the technology itself has been available for more than ten years now, there is still a certain amount of uncertainty among researchers and users as to whether VR will one day fulfill all it's promises. In this chapter we are giving an overview of the implementation of the technology in our mental health research facility in Basel, Switzerland. The development of two applications for use with claustrophobic and acrophobic patients perspectively serves just as an example within this context. Some may say, the chapter is too much based on technical considerations. Strictly speaking, VR is pure technology, even knowing that this special form of technology has sensory, psychological and even philosophical implications not known from other human computer interfaces so far. As far as we are concerned, the development of the technology for use within the mental health sector has merely just begun. As today's mostly used immersive output devices (Head-mounted Displays, shutter glasses) do not have a satisfactory resolution, do restrict movements and prevent multi-user-capabilities, there will be a soar of mental health applications the day some or at least the most important of these obstacles have been overcome.

Diminished plasma cGMP during weightlessness

We performed an experiment within the project "RLF" (Russian long-term flight) on a cosmonaut onboard the space station MIR. For creating an analogue to orthostatic stress, we used lower body negative pressure (LBNP) as stimulus. Decrease in central and peripheral baroreceptor load by LBNP can be used as a cardiovascular countermeasure in cosmonauts or for inducing endocrine responses. Altered steady-state plasma concentration values of volume sensitive hormones have been observed inflight as well as postflight. Within this project we measured plasma ANP and cGMP as second messenger. Changes in plasma cGMP concentration are generally considered to be a good indicator of those in ANP activity. However, in our experiments depression of cGMP during space flight was more impressive than ANP decline. We are not aware of previous measurements of plasma cGMP under these conditions, and believe to be the first to report complete suppression of plasma cGMP during long-term stay in space.

A Novel Effect in Phycomyces Phototropism : Positive Bending and Compensation Spectrum in Far UV

A novel effect-positive phototropic bending under far UV irradiation (between 260 and 305 nanometers) at low intensities-is reported. Natural compensation points (intensities which cause no bending under unilateral irradiation) have been determined for different wavelengths. The curve connecting these points, the compensation spectrum, divides the intensity-wavelength plane into areas of negative and positive tropism. It is further shown that a highly asymmetrical pattern of light stimulus within the sporangiophore underlies the symmetrical growth response at each compensation point. This suggests that some unknown additional factor is involved in perceiving a UV stimulus at the level of the photoreceptor. It is also demonstrated here that positive tropism in the UV range is due to a lens effect. We conclude that the hypothesis of optical attenuation of the stimulus (considered until now as the most plausible explanation of negative tropism in the UV spectral range) must be dismissed. The results presented here represent the first application of our quantitative theoretical consideration of spatial factors in phototropism heretofore neglected by others.