BackgroundAlthough clinical studies of the high-flow nasal cannula (HFNC) and its effect on positive end-expiratory pressure (PEEP) have been done, the washout effect has not been well evaluated. Therefore, we made an experimental respiratory model to evaluate the respiratory physiological effect of HFNC.MethodsAn airway model was made by a 3D printer using the craniocervical 3D-CT data of a healthy 32-year-old male. CO2 was infused into four respiratory lung models (normal-lung, open- and closed-mouth models; restrictive- and obstructive-lung, open-mouth models) to maintain the partial pressure of end-tidal CO2 (PETCO2) at 40 mmHg. HFNC flow was changed from 10 to 60 L/min. Capnograms were recorded at the upper pharynx, oral cavity, subglottic, and inlet sites of each lung model.ResultsWith the normal-lung, open-mouth model, 10 L/min of HFNC flow decreased the subglottic PETCO2 to 30 mmHg. Increasing the HFNC flow did not further decrease the subglottic PETCO2. With the normal-lung, closed-mouth model, HFNC flow of 40 L/min was required to decrease the PETCO2 at all sites. Subglottic PETCO2 reached 30 mmHg with an HFNC flow of 60 L/min. In the obstructive-lung, open-mouth model, PETCO2 at all sites had the same trend as in the normal-lung, open-mouth model. In the restrictive-lung, open-mouth model, 20 L/min of HFNC flow decreased the subglottic PETCO2 to 25 mmHg, and it did not decrease further. As HFNC flow was increased, PEEP up to 7 cmH2O was gradually generated in the open-mouth models and up to 17 cmH2O in the normal-lung, closed-mouth model.ConclusionsThe washout effect of the HFNC was effective with relatively low flow in the open-mouth models. The closed-mouth model needed more flow to generate a washout effect. Therefore, HFNC flow should be considered based on the need for the washout effect or PEEP.
A bacterium capable of producing a deep blue pigment was isolated from the environment and identified as Pantoea agglomerans. The pigment production characteristics of the bacterium under various conditions were studied. The optimal agar plate ingredients for pigment production by the bacterium were first studied: the optimal ingredients were 5 g/liter glucose, 10 g/liter tryptic soy broth, and 40 g/liter glycerol at pH 6.4. Bacterial cells grew on the agar plate during the incubation, while the pigment spread into the agar plate, meaning that it is water soluble. Pigment production was affected by the initial cell density. Namely, at higher initial cell densities ranging from 10 6.3 to 10 8.2 CFU/cm 2 on the agar plate, faster pigment production was observed, but no blue pigment was produced at a very high initial density of 10 9.1 CFU/cm 2 . Thus, the cell population of 10 8.2 CFU/cm 2 was used for subsequent study. Although the bacterium was capable of growing at temperatures above and below 10°C, it could produce the pigment only at temperatures of >10°C. Moreover, the pigment production was faster at higher temperatures in the range of 10 to 20°C. Pigment production at various temperature patterns was well described by a new logistic model. These results suggested that the bacterium could be used in the development of a microbial temperature indicator for the low-temperature-storage management of foods and clinical materials. To our knowledge, there is no other P. agglomerans strain capable of producing a blue pigment and the pigment is a new one of microbial origin.
Adrenal glands play a central role in the secretion of steroid hormones and catecholamines. Previous studies have revealed that molecules engaged in phosphoinositide (PI) turnover are expressed in the adrenal gland, suggesting the importance of PI signaling in adrenal signal transduction. Diacylglycerol kinase (DGK) catalyzes the phosphorylation of diacylglycerol (DG), a major second messenger in the PI signaling cascade. The DGK family is expressed in distinct patterns in endocrine organs at the mRNA and protein levels. Nevertheless, little is known about the characteristics and morphological aspects of DGKs in the adrenal gland. We have performed immunohistochemical analyses to investigate the expression and localization of DGK isozymes, together with PI signaling molecules, in the adrenal gland at the protein level. Our results show that the DGK family and a set of PI signaling molecules are expressed intensely in zona glomerulosa cells and medullary chromaffin cells in the adrenal gland. In adrenal cells, DGKγ localizes to the Golgi complex, DGKε to the plasma membrane, and DGKζ to the nucleus. These findings show the distinct expression and subcellular localization of DGK isozymes and PI signaling molecules in the adrenal gland, suggesting that each DGK isozyme has a role in signal transduction in adrenal cells, especially in the zona glomerulosa and medulla.
BackgroundDexmedetomidine (Dex) provides sedation and analgesia by acting on central alpha-2 receptors and is suitable for use after extubation because it has little respiratory depression. Considering the sympathoinhibitory and anxiolytic action of Dex, there is the possibility that Dex might reduce the incidence of atrial fibrillation (AF), which is recognized as a common complication after cardiovascular surgery. We investigated whether the postoperative incidence of AF decreased in patients who received Dex only during the nighttime in the intensive care unit (ICU).MethodsWe retrospectively reviewed ICU charts to determine the incidence of AF and associated factors during the 2-day period after tracheal extubation in patients who underwent cardiovascular surgery from November 2009 to November 2010. The patients were divided into a Dex group (n = 16) and a non-Dex group (n = 29).ResultsThere were no differences in AF risk factors except for diabetes between the two groups. The average rate of Dex administration was 0.3 ± 0.2 μg/kg/h. There were also no differences between the groups in heart rate during the daytime, central venous pressure, body temperature, white blood cell count, serum level of C-reactive protein, catecholamine use, beta-blocker use, and amount of fentanyl. AF developed in one patient in the Dex group (6.3 %) and ten patients in the non-Dex group (34.5 %) during the observation period, and the difference was significant (p = 0.035). None of the risk factors for AF was significantly associated with AF in univariate analysis; however, multivariate logistic regression analysis using age, Dex use, and beta-blocker use, extracted because their p values in univariate analysis were not exceeding 0.15, showed that Dex use was the only factor associated with the development of AF (p = 0.045, odds ratio 9.75 [1.05–90.8]).ConclusionsThe results suggest that adequate sedation with Dex during the nighttime can reduce the incidence of AF in cardiovascular surgery patients after extubation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.