Stroke volume variation (SVV) during mechanical ventilation predicts preload responsiveness. We hypothesized that the prone position would alter the performance of this dynamic indicator.
Two ...parallel groups of ventilated neurosurgical patients with low tidal volume (6-8 ml.kg-1) were studied before surgical incision. SVV was measured at T0, T15 and T30 min during a fluid volume expansion (250 mL hetastarch 6% over 30 min) with patients in either the supine (N.=29; Supine group) or prone position (N.=23; Prone group). Fluid responsiveness was defined as an increase in the stroke volume index (SVI) of ≥20% at T30. Receiver-operating characteristics (ROC) curves were generated for SVV.
Prone positioning significantly increased SVV. Volume expansion in the Prone group increased SVI but led to a decline in SVV from 16% (12-22; median, 25-75th percentile) at T0 to 9% (8-13%) at T30. These effects on SVI and SVV were more pronounced compared to those obtained in the Supine group (P ≤0.05). Fluid responsiveness was predicted by SVV >12% at T0 (sensitivity 88%, specificity 62%) in the Supine group. In the Prone group, the area under the ROC curve of SVV (0.53; 95% confidence interval 0.27-0.79) did not allow the determination of a threshold SVV value.
In ventilated patients with low tidal volume, a prone position may have a direct effect on the heart that alters the performance of SVV in predicting fluid responsiveness. External factor such as prone position renders difficult the interpretation of SVV as a dynamic indicator of cardiac preload.
The decline of tissue regenerative potential of skin and hair is a hallmark of physiological ageing and may be associated with age‐related changes in tissue‐specific stem cells and/or their ...environment. Human hair follicles (hHF) contain keratinocytes having the property of stem cells such as clonogenic potential. Growth capacity of hHF keratinocytes shows that most of the colony‐forming cells are classified as holoclones, meroclones or paraclones when analysed in a clonal assay (Cell, Volume 76, page 1063). Despite the well‐known impact of ageing on human hair growth, little is known about changes in hHF keratinocyte clonogenic potential with age. This study aimed at assessing the clone‐forming efficiency (CFE) of hHF keratinocytes from three age groups of human donors. It demonstrates that ageing affects hHF keratinocyte CFE.
Supercontinuum generation in large mode-area microstructured fibers is demonstrated by launching into the fiber ns pulses from a passively Q-switched Nd:YAG laser. The special properties of these ...fibers open the way to compact, single-mode, high-power supercontinuum sources with a low divergence of the output beam. The nonlinear phenomena leading to the formation of the broad spectrum are also described.
Abstract
Context: Growth hormone (GH) plays a critical role in glucose homeostasis and linear growth during childhood. GH secretion is controlled by multiple neurotransmitters and hormones. Sleep ...is also a powerful stimulus for GH secretion. In children, GH pulses occur after sleep onset in association with slow-wave sleep (SWS), but it is unclear if undisrupted sleep is required for normal GH secretion. Given the rising incidence of pediatric sleep disorders such as obstructive sleep apnea (OSA) that cause sleep fragmentation, it is critical to determine whether sleep fragmentation during childhood may dysregulate the somatotropic axis.
Objective
To quantify how undisrupted vs fragmented sleep affects GH secretion in children.
Methods
Pubertal subjects (10 M, 9 F; 9.1-14.4 yrs) were randomized to two overnight polysomnographic studies with frequent blood sampling (q10min) to measure GH: fourteen were healthy subjects studied with or without SWS disruption via auditory stimuli (3 sec, 1500 Hz tones, 40-100 dB followed by 18 sec of a 75 dB noise simulating a knock on the door) and five were subjects with OSA studied with or without prescribed continuous positive airway pressure (CPAP); the latter condition was expected to have sleep fragmentation due to untreated OSA. GH pulses were identified using sparse deconvolution. Studies without auditory stimuli or when using CPAP were combined and analyzed as 'undisrupted sleep'. The relationship between GH pulse rate per hour and sleep stage was evaluated using Poisson generalized estimating equations.
Results
In SWS disruption studies, an average of 77.51 ± 13.61 (range 23-190) auditory stimuli were delivered, causing a 40.02 ± 7.78% decrease in SWS in favor of lighter sleep stages. In subjects with OSA, CPAP withdrawal caused a slight increase in the apnea hypopnea index (1.08 ± 0.10 vs. 2.20 ± 1.70 events/hour of sleep, p=0.07) with no change in sleep stage durations. During undisrupted sleep, subjects had an average of 0.91 ± 0.067 GH pulses/hour with a mean pulse amplitude of 10.03 ± 1.00 ng/mL and mean basal secretion rate of 0.26 ± 0.10 ng/ml per min. GH pulses occurred more frequently during SWS (2.3 pulses/hour SWS, amplitude 9.92 ± 2.59 ng/mL) than during any other sleep stage (P < 0.001). Neither form of sleep disruption affected the distribution of GH pulses across sleep stages, GH pulse amplitude and frequency, nor basal GH secretion.
Conclusion
In children, nocturnal GH pulses are temporally associated with SWS. However, neither acute fragmentation of SWS nor nocturnal arousals from OSA altered basal or pulsatile GH secretion, indicating that somatotrophic axis activity is preserved in the face of acute sleep disruption in children.
Presentation: Sunday, June 12, 2022 11:45 a.m. - 12:00 p.m.
Interglacial to glacial transitions represent the most drastic turnovers in the Quaternary climate system. Yet, millennial-scaled climate variability and stochastic internal variability that result ...in (inter)glacial transitions remain poorly understood. Here, three speleothems from two different cave systems in Belgium are investigated to characterize the Eemian to early Weichselian transition. The speleothems show high reproducibility for δ13C, interpreted as a proxy for past vegetation activity, controlled by type of vegetation above the cave. All three speleothems show a drastic increase in δ13C between 118 and 117 ka, reflecting a rapid change in vegetation from last interglacial temperate tree species towards glacial open-grass vegetation. This transition shows a strong affinity with the Late Eemian Aridity Pulse (LEAP) at 118 ± 1 ka, previously identified in pollen records from Western Germany. An age of 117.7 ± 0.5 ka is determined for the start of this transition in the Belgian speleothems. The speleothem records show a distinct transition in the proxies between Eemian optimum conditions and increased variability during the glacial inception and therefore the Eemian-Weichselian transition is set at 117.7 ± 0.5 ka in the speleothem records. High-resolution trace element analysis shows that the transition is initiated by a cooling pulse followed by a decrease in precipitation. Through comparison with other archives, including North-Atlantic sedimentary records, it is proposed that the transition at 117.7 ka constitutes an internal climate response caused by a substantial input of freshwater from degraded ice-sheets by the end of the Eemian (∼120-118 ka).
•A paleoclimate reconstruction of the Eemian-Weichselian transition is presented.•The EWT occurs at 117.7 ± 0.5 ka in the records.•This transition is linked with a larger regional cooling.•There is evidence for a climatic connection with the North Atlantic region.
A person's sexual and emotional life is greatly impacted after allogeneic hematopoietic stem cell transplantation (allo-HSCT). This topic is not addressed very much by patients and caregivers. ...Physical, endocrine and genital chronic graft versus host disease (cGVHD)-related disorders are multiple and intertwined with psychological disorders. The Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) has issued recommendations for a better gynecological monitoring of female recipients after allo-HCT. A patient booklet was also offered to patients in the form of questions and answers to facilitate discussions between patients and caregivers and to improve the management of sexual and emotional life after transplant.
This study presents a methodological approach for the visualization of the glycocalyx by electron microscopy. The glycocalyx is a three dimensional network mainly composed of glycolipids, ...glycoproteins and proteoglycans associated with the plasma membrane. Since less than a decade, the epithelial and endothelial glycocalyx proved to play an important role in physiology and pathology, increasing its research interest especially in vascular functions. Therefore, visualization of the glycocalyx requires reliable techniques and its preservation remains challenging due to its fragile and dynamic organization, which is highly sensitive to the different process steps for electron microscopy sampling. In this study, chemical fixation was performed by perfusion as a good alternative to conventional fixation. Additional lanthanum nitrate in the fixative enhances staining of the glycocalyx in transmission electron microscopy bright field and improves its visualization by detecting the elastic scattered electrons, thus providing a chemical contrast.
Cancer patients who develop a deep-vein thrombosis (DVT) or a pulmonary embolism (PE) are at higher risk of death than similar cancer patients who do not develop DVT or PE. The impact of isolated ...superficial venous thrombosis (SVT) (i.e. without DVT or PE) on the prognosis of cancer patients is unknown.
Data from the OPTIMEV, multicentre, observational study, to compare at 3 years the incidences of death, DVT-PE recurrence and bleeding of cancer patients with objectively confirmed SVT vs. cancer patients with DVT (matched 1:2 on age, sex, cancer stage) and vs. patients with SVT without cancer (matched 1:3 on age and sex).
Cancer patients with SVT (n = 34) had a high risk of death (23.2%patient-year(PY)), that was similar to that of cancer patients with DVT (aHR = 1.00.6–1.9) and higher to that of SVT patients without cancer (aHR = 9.03.5–23.1). Cancer patients with SVT received anticoagulants for a median duration of 45 days and had a high risk of DVT-PE recurrence (6.0%PY), similar to that of cancer patients with DVT (adjusted cause-specific HR (aCHR) = 1.50.4–5.8) and higher to that of SVT patients without cancer (aCHR = 2.90.7–11.9). In our population, venous thrombosis on varicose veins was associated with a lower risk of death (aHR = 0.60.3–1.0) and DVT-PE recurrence (aCHR = 0.60.2–1.7).
Our results suggest that cancer patients with SVT have a poor prognosis, similar to that of patients with cancer-related DVT. The high rate of DVT-PE recurrence suggests that such patients may need longer duration of anticoagulant treatment.
•Cancer patients who develop VTE have a poorer prognosis than those who don't.•Long-term prognosis of cancer patients who develop SVT is unknown•Risk of death appears similar between cancer patients with SVT vs. DVT•Risk of death is twice lower in cancer patients with thrombosis in varicose veins.
•Fe(VI) performance and residuals were evaluated with three Fe(III) salts and a gold mine effluent.•Final NO3− with Fe(VI) produced from Fe(NO3)3 was 4 times higher than either FeCl3 or ...Fe2(SO4)3.•Fe(VI) produced from Fe2(SO4)3 was the only one to remove the CN− and NH3-N almost totally (∼99%).•Production yield of Fe(VI) with FeCl3 was lower than Fe2(SO4)3 or Fe(NO3)3.•Fe2(SO4)3 seems the most appropriate for Fe(VI) synthesis for use in mine effluents treatment.
Ferrate Fe(VI) is increasingly used for the treatment of several contaminants in drinking water and municipal/industrial waste water. Recent findings also show that Fe(VI) is a promising alternative for the treatment of gold mine effluents contaminated by cyanides (CN−), thiocyanates (SCN−), and ammonia nitrogen (NH3-N). However, the ferric Fe(III) salt used in Fe(VI) synthesis could affect this alternative’s efficiency and costs, as well as residual contaminants in the treated effluent. The objective of this study was to evaluate the influence of three Fe(III) salts on the performance of Fe(VI) in the treatment of gold mine effluents and the residual contaminants produced in the process. To do so, the performance of wet Fe(VI) synthesized with ferric nitrate Fe(NO3)3, ferric chloride (FeCl3), or ferric sulfate Fe2(SO4)3 was evaluated for the treatment of a real gold mine effluent, with final adjustment of pH at ∼7. The results showed that for the effluents treated with Fe(VI) synthesized in the presence of Fe(NO3)3, the final NO3− concentrations were 4 times higher relative to those in the treated effluents with Fe(VI) synthesized from either FeCl3 or Fe2(SO4)3. The use of Fe2(SO4)3 in the wet Fe(VI) preparation did not entail a significant increase of the final SO42− concentrations, which were very similar to initial ones (1220 vs. 1012 mg/L). At the same time, Fe(VI) synthesized from Fe2(SO4)3 was the only one to remove the CN− and NH3-N almost totally (∼99%). Finally, the production yield of Fe(VI) with FeCl3 was lower than Fe2(SO4)3 or Fe(NO3)3 (3400 vs. 5500 and 5635 mg/L, respectively). This low yield production of Fe(VI) from FeCl3 entails more costly production costs. Thus, Fe2(SO4)3 is potentially the most appropriate Fe(III) salt source for Fe(VI) synthesis for use in the treatment of contaminated mine effluents.
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