Mechanism of low-frequency, low-intensity ultrasound modulation of the mouse retina.

Objective.Ultrasound has been shown to modulate the activity of retinal ganglion cells (RGCs) in mice, but the mechanism remains poorly understood. This study aims to address this question.Approach.Multi-electrode recordings together with pharmacological methods were used to investigate the possible cellular/circuitry mechanism(s) underlying the neuronal modulation induced by low-frequency (1 MHz), low-intensity (ISPTA0.5 W cm-2) ultrasound stimulation.Main results.We found that ultrasound activated mechanosensitive channels (transient receptor potential vanilloid 4 (TRPV4) channels are involved) in Müller cells, causing the release of glutamate, which acts on the extrasynapticN-methyl-D-aspartate receptors of RGCs, thus leading to the modulation of neuronal activity.Significance.Our results reveal a novel mechanism of low-frequency, low-intensity ultrasound modulation, involving TRPV4 as a mechanosensitive target for ultrasound and glutamate as an essential mediator of neuron-glia communication. These findings also demonstrate that the mechanical-force-mediated pathway is important for retinal signal modulation during visual processes, such as visual accommodation.

Low-frequency, low-intensity ultrasound modulates light responsiveness of mouse retinal ganglion cells.

Objective. Ultrasound modulates the firing activity of retinal ganglion cells (RGCs), but the effects of lower-frequency, lower-intensity ultrasound on RGCs and underlying mechanism(s) remain poorly understood. This study aims to address these questions.Approach. Multi-electrode recordings were used in this study to record the firing sequences of RGCs in isolated mouse retinas. RGCs' background firing activities as well as their light responses were recorded with or without ultrasound stimulation. Cross-correlation analyses were performed to investigate the possible cellular/circuitry mechanism(s) underlying ultrasound modulation.Main results. It was found that ultrasound stimulation of isolated mouse retina enhanced the background activity of ON-RGCs and OFF-RGCs. In addition, background ultrasound stimulation shortened the light response latency of both ON-RGCs and OFF-RGCs, while enhancing part of the RGCs' (both ON- and OFF-subtypes) light response and decreasing that of the others. In some ON-OFF RGCs, the ON- and OFF-responses of an individual cell were oppositely modulated by the ultrasound stimulation, which suggests that ultrasound stimulation does not necessarily exert its effect directly on RGCs, but rather via its influence on other type(s) of cells. By analyzing the cross-correlation between the firing sequences of RGC pairs, it was found that concerted activity occurred during ultrasound stimulation differed from that occurred during light stimulation, in both spatial and temporal aspects. These results suggest that the cellular circuits involved in ultrasound- and light-induced concerted activities are different and glial cells may be involved in the circuit in response to ultrasound.Significance. These findings demonstrate that ultrasound affects neuronal background activity and light responsiveness, which are critical for visual information processing. These results may also imply a hitherto unrecognized role of glial cell activation in the bidirectional modulation effects of RGCs and may be critical for the nervous system.

A new species of the genus Oxyporus Fabricius (Coleoptera: Staphylinidae: Oxyporinae) in Yunnan Province, China.

A new species of the genus Oxyporus Fabricius, 1775 is described based on specimens collected in Yunnan Province, China, namely Oxyporus (Oxyporus) mojiangius Li, sp. nov. from Mojiang County. The number of Oxyporus species worldwide is thus increased to 132. Color images of the habitus and aedeagus of the new species are included. A key to the Oxyporus species of Yunnan Province is provided.

[Preparation of evodiamine-glycyrrhizic acid micelles with glycyrrhizic acid as carrier and their anti-hepatic fibrosis activity].

This study aimed to prepare evodiamine-glycyrrhizic acid(EVO-GL) micelles to enhance the anti-hepatic fibrosis activity of evodiamine. Firstly, EVO-GL micelles were prepared with use of thin film dispersion method. With particle size, encapsulation efficiency, loading capacity of micelles and the solubility of evodiamine as the indexes, the effect of different factors on micelles was observed to screen the optimal preparation methods and process. Then the pharmaceutical properties and the therapeutic effects of EVO-GL micelles prepared by optimal process were evaluated on CCl_4-induced hepatic fibrosis. The results showed that the micelles prepared by the thin film dispersion method had an even size, with an average particle size of(130.80±12.40)nm, Zeta potential of(-41.61±3.12) mV, encapsulation efficiency of 91.23%±1.22%, drug loading of 8.42%±0.71%, high storage stability at 4 ℃ in 3 months, and slow in vitro release. Experimental results in the treatment of CCl_4-induced hepatic fibrosis in rats showed that EVO-GL micelles had a synergistic anti-hepatic fibrosis effect, which significantly reduced the liver function index of hepatic fibrosis rats. In conclusion, the EVO-GL micelles prepared with glycyrrhizic acid as a carrier would have a potential application prospect for the treatment of hepatic fibrosis.

A U-shaped association between serum betaine and incident risk of first ischemic stroke in hypertensive patients.

BACKGROUND & AIMS: Betaine (a micronutrient) has important biological functions (e.g., preventing premature apoptosis and serving as a methyl donor). We investigated the association between baseline serum betaine and the incident risk of first stroke in hypertensive patients. METHODS: We conducted a nested case-control study, including 622 patients with first stroke (including 502 ischemic stroke, 118 hemorrhagic stroke and 2 uncertain type of stroke) and 622 matched controls from the China Stroke Primary Prevention Trial (CSPPT). The study was conducted from May 2008 to August 2013. The study outcomes included first stroke and its subtypes: first ischemic and hemorrhagic stroke. RESULTS: There was a U-shaped association between baseline serum betaine and the risk of first ischemic stroke. The risk of first ischemic stroke decreased with the increment of betaine (per 10 µmol/L increase: OR, 0.87; 95%CI: 0.77-0.99) in patients with betaine <77.7 µmol/L, while the risk of first ischemic stroke increased with the betaine increment (OR, 1.17; 95%CI: 1.01-1.36) in patients with betaine ≥77.7 µmol/L. However, there was no significant association between serum betaine and risk of first hemorrhagic stroke (per 10 µmol/L increase: OR, 0.98; 95%CI: 0.82-1.17). CONCLUSIONS: There was a U-shaped association between baseline betaine levels and the risk of first ischemic stroke in hypertensive patients, with a turning point at about 77.7 µmol/L. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT00794885.

A new species of the genus Oxyporus Fabricius (Coleoptera: Staphylinidae: Oxyporinae) in Yunnan Province, China.

A new species of the genus Oxyporus Fabricius, 1775 is described based on specimens collected in Yunnan Province, China, namely Oxyporus (Oxyporus) tuantianius sp. nov. from Xinping County. The number of Oxyporus species worldwide is thus increased to 131. Color images of the habitus and aedeagus of the new species are included. A key to the Oxyporus species of Yunnan Province is provided.

Down-regulated long non-coding RNA RNAZFHX4-AS1 suppresses invasion and migration of breast cancer cells via FAT4-dependent Hippo signaling pathway.

Breast cancer is ranked as the second leading cause of cancer-related deaths among women. Accumulating evidences have revealed that long non-coding RNAs (lncRNAs) are involved in human tumorigenesis owing to the regulation of essential pathways for tumor initiation and progression. Herein, the current study aimed to explore the regulatory mechanism of lncRNA ZFHX4-AS1 in breast cancer in relation to the Hippo signaling pathway. Initially, microarray analysis was conducted to screen out differentially expressed lncRNAs related to breast cancer. Next, the functional role of lncRNA ZFHX4-AS1 in breast cancer was determined using ectopic expression, knockdown, and reporter assay experiments. Subsequently, lncRNA ZFHX4-AS1, TAF4, TAZ, and YAP expressions were determined, followed by verification of the targeting relationship between lncRNA ZFHX4-AS1 and TAF4. Then cell proliferation, invasion, migration, cell cycle, and apoptosis were measured. Lastly, tumor growth and metastasis were detected by tumor xenograft in nude mice. LncRNA ZFHX4-AS1 was found to be highly expressed while FAT4 was poorly expressed in breast cancer tissues. FAT4 was the target gene of lncRNA ZFHX4-AS1, and lncRNA ZFHX4-AS1 silencing increased FAT4 expressions, while decreased YAP and TAZ expressions. In addition, knockdown of lncRNA ZFHX4-AS1 suppressed breast cancer cell proliferation, migration, and invasion as well as tumor growth, blocked cell cycle entry, while promoted cell apoptosis by inhibiting the Hippo signaling pathway. In conclusion, our findings reveal that lncRNA ZFHX4-AS1 silencing exerts an inhibitory effect on breast cancer development by suppressing the activation of the Hippo signaling pathway via FAT4.

Serum Trimethylamine N-Oxide Concentration Is Positively Associated With First Stroke in Hypertensive Patients.

Background and Purpose- Trimethylamine N-oxide (TMAO)-a gut derived metabolite-has been shown to be atherogenic. It remains unknown whether TMAO is associated with the risk of first stroke. We aimed to determine the association between serum TMAO levels and first stroke in hypertensive patients without major cardiovascular diseases and examine any possible effect modifiers. Methods- We used a nested case-control design, using data from the CSPPT (China Stroke Primary Prevention Trial), including 622 patients with first stroke and 622 matched controls. The study was conducted from May 2008 to August 2013. The primary outcome was a first stroke. Results- After adjusting for choline, L-carnitine, and other important covariates, including baseline systolic blood pressure and time-averaged systolic blood pressure, during the treatment period, the risk of first stroke increased with each increment of TMAO level (per natural log [TMAO] increment: odds ratio, 1.22; 95% CI, 1.02-1.46). Consistently, compared with participants in the lowest tertile (<1.79 µmol/L) of serum TMAO levels, a significantly higher risk of first stroke was found in those in higher TMAO tertiles (≥1.79 µmol/L; odds ratio, 1.34; 95% CI, 1.00-1.81) or in TMAO tertile 3 (≥3.19 µmol/L; odds ratio, 1.43; 95% CI, 1.02-2.01). In the exploratory analysis, we observed an interaction between TMAO and folate levels (≥7.7 [median] versus <7.7 ng/mL) on first stroke ( P for interaction, 0.030). Conclusions- Higher TMAO levels were associated with increased risk of first stroke in hypertensive patients. Our finding, if further confirmed, calls for a carefully designed clinical trial to further evaluate the role of higher TMAO levels on outcomes in hypertensive patients. Clinical Trial Registration- URL: https://www.clinicaltrials.gov . Unique identifier: NCT00794885.

[Glycyrrhetinic acid selectively inhibits proliferation of hepatocellular carcinoma cells in vitro].

OBJECTIVE: To investigate the selective inhibitory effect of glycyrrhetinic acid on 4 hepatocellular carcinoma (HCC) cells with different proliferation rates and explore the underlying mechanisms. METHODS: MTT method was used to detect the proliferation rates of 4 HCC cell lines, namely SMMC-7721, SK-HEP1, HEPG2 and HEP3B. Following treatment of the cells with glycyrrhetinic acid (5, 10, 20, 30, 40, and 60 µmol/L), the cell viability was analyzed using MTT assay and the expressions of total ERK protein, p-ERK protein and topoisomerase IIα were detected using Western blotting. RESULTS: Among the 4 cell lines, SMMC-7721 had the lowest and SK-HEP1 had the highest proliferation rate. Treatment with glycyrrhetinic acid for 48 h dose-dependently inhibited the proliferation of all the 4 cell lines in vitro and produced the strongest inhibitory effect in SMMC-7721 cells with the IC50 of 28.04 µmol/L. The proliferation rate of the cells was positively correlated with the expression levels of p-ERK and topoisomerase IIα, which were the lowest in SMMC-7721 cells and the highest in SK-HEP1 cells. Treatment with 50 µmol/L glycyrrhetinic acid significantly down-regulated the expressions of p-ERK and topoisomerase IIα in the 4 HCC cell lines (P<0.05), while 25 µmol/L glycyrrhetinic acid significantly reduced the expression of topoisomerase IIα and p-ERK in SMMC-7721, HEPG2 and HEP3B cells (P<0.05) but not in SK-HEP1 cells. CONCLUSION: Glycyrrhetinic acid can inhibit the proliferation of different HCC cells particularly in cells with a low proliferation rate. The inhibitory effect of glycyrrhetinic acid might be mediated by reducing the expressions of topoisomerase IIα and inhibiting the ERK pathway.

Two new species of the genus Oxyporus Fabricius (Coleoptera: Staphylinidae: Oxyporinae) in Yunnan Province, China.

Two new species of the genus Oxyporus Fabricius, 1775 are described based on specimens collected in Yunnan Province, China, namely Oxyporus (Oxyporus) fentianae sp. nov. from Mojiang County and Oxyporus (Oxyporus) ningerius sp. nov. from Ninger County. The number of Oxyporus species worldwide is thus increased to 130. Color images of the habitus and aedeagi of the two new species are included. A key to the Oxyporus species of Yunnan Province is provided.

The effect of environmental factors on the differential expression of miRNAs in patients with chronic obstructive pulmonary disease: a pilot clinical study.

Objective: The objective of the study was to analyze the effect of environmental factors on the differential expression of microRNAs in the peripheral blood of migratory and local patients in northern People's Republic of China and on clinical symptoms of local patients in northern People's Republic of China with COPD. Methods: A total of 118 patients in the northern region and 8 migratory patients were enrolled in this prospective study. We collected general information. Blood samples were collected from 9 patients in the Beijing group, from 8 patients in the migratory group and from 9 healthy control subjects. After extracting the total RNA from these 3 groups, serum miRNA was identified by Solexa sequencing. We collected COPD assessment test (CAT) and Modified British Medical Research Council (mMRC) scores at different levels of air pollution and also collected the number of exacerbations over the year prior to the baseline and in the year preceding the follow-up. Results: In total 9 miRNAs were differentially expressed. When air quality index (AQI) >100, the CAT and mMRC scores at baseline were significantly higher than those when the AQI ≤100 (P<0.001). When AQI >100, the follow-up CAT and mMRC scores were significantly higher than those when AQI ≤100 (P<0.001). Follow-up mMRC scores were significantly higher than baseline scores (P=0.04). When AQI ≤100, the baseline CAT score of the group with fewer symptoms was 6.50 (4.00-8.75). However, when AQI >100, the baseline CAT score of this fewer symptoms group was 10.00 (6.25-12.00). The median CAT score was close to 10. When AQI ≤100, the follow-up CAT score of the fewer symptoms group was 8.00 (4.25-12.00). However, when AQI >100, the follow-up CAT score of the fewer symptoms group was 9.50 (6.00-16.75). The median CAT score was close to 10. Conclusion: Environmental factors may cause differential expression of miRNAs in the peripheral blood of migratory and local patients in northern People's Republic of China. Air pollution may aggravate clinical symptoms of patients with COPD.

[Pharmacokinetics and oral bioavailability of palmatine and jatrorrhizine in Huangteng in rats].

In this study, the total alkaloids of Huangteng were given to the rats by the methods of intragastric administration and tail vein. After the concentration changes of palmatine and jatrorrhizine in the plasma of rats were determined by RP-HPLC, pharmacokinetic parameters and oral bioavailability were calculated by 3P97 software. After the rats were pre-treated with total alkaloid 60 mg•kg⁻¹ by the methods of intragastric administration and tail vein, the main pharmacokinetic parameters were determined as follows： in the intragastric administration group, the Cmax of palmatine and jatrorrhizine were (0.91±0.06), (0.70±0.08) mg•L⁻¹; tmax of palmatine and jatrorrhizine were (35.24±0.83), (47.76±1.24) min; t1/2 of palmatine and jatrorrhizine were (187.03±1.53), (105.64±16.99) min, AUC of palmatine and jatrorrhizine were (280.30±18.69), (144.36±1.06) mg•min•L⁻¹; in the intravenous injection group, the t1/2 of palmatine and jatrorrhizine were (172.18±12.38), (147.26±1.82) min; AUC of palmatine and jatrorrhizine were (2 553.14±214.91), (328.83±10.81) mg•min•L⁻¹. The oral bioavailability of palmatine was 10.98% and jatrorrhizine was 43.90%.

A new species of the genus Oxyporus Fabricius (Coleoptera: Staphylinidae: Oxyporinae) in Yunnan Province, China.

Oxyporus (Oxyporus) wangae sp. nov. is described from Yunnan, China. Color images of the habitus and aedeagus of the new species are included. A key to the genus Oxyporus of Yunnan Province species is provided.

Synergistic protection of Schizandrin B and Glycyrrhizic acid against bleomycin-induced pulmonary fibrosis by inhibiting TGF-ß1/Smad2 pathways and overexpression of NOX4.

Pulmonary fibrosis, a progressive and lethal lung disease, is a major therapeutic challenge for which new therapeutic strategies are warranted. Schisandrin B (Sch B) and Glycyrrhizic acid (GA) are the principal active ingredients of Schisandra chinensis and Glycyrrhiza glabra respectively, which have been reported to protect against lung injures. The present study was aimed at exploring the combinatorial therapeutic effects on bleomycin-induced pulmonary fibrosis. Lung fibrotic injuries were induced in mice by a single intratracheal instillation of 5mg/kg bleomycin (BLM). Then, these mice were administered with Sch B (100mg/kg) or/and GA (75mg/kg) for 28days. BLM-triggered structure distortion, collagen overproduction, excessive inflammatory infiltration, pro-inflammatory cytokine release, and oxidative stress damages in lung tissues were attenuated to a higher degree by combinatorial treatment than by treatment of the individual agents. The expression of TGF-ß1 and the phosphorylation of its downstream target, Smad2 were enhanced by BLM, but weakened by Sch B or/and GA. Furthermore, the significant overexpression of NADPH oxidase 4 (NOX4) was observed in BLM-induced pulmonary fibrosis, which was inhibited by Sch B or/and GA. Our study reveals that the synergistic protection by Sch B and GA against BLM-induced pulmonary fibrosis is correlated to its anti-inflammatory, anti-oxidative and anti-fibrotic properties, involving inhibition of TGF-ß1/Smad2 signaling pathways and overexpression of NOX4.

Hundred top-cited articles focusing on acute kidney injury: a bibliometric analysis.

BACKGROUND: Acute kidney injury (AKI) is a major global health issue, associated with poor short-term and long-term outcomes. Research on AKI is increasing with numerous articles published. However, the quantity and quality of research production in the field of AKI is unclear. METHODS AND ANALYSIS: To analyse the characteristics of the most cited articles on AKI and to provide information about achievements and developments in AKI, we searched the Science Citation Index Expanded for citations of AKI articles. For the top 100 most frequently cited articles (T100), we evaluated the number of citations, publication time, province of origin, journal, impact factor, topic or subspecialty of the research, and publication type. RESULTS: The T100 articles ranged from a maximum of 1971 citations to a minimum of 215 citations (median 302 citations). T100 articles were published from 1951 to 2011, with most articles published in the 2000s (n=77), especially the 5-year period from 2002 to 2006 (n=51). The publications appeared in 30 journals, predominantly in the general medical journals, led by New England Journal of Medicine (n=17), followed by expert medical journals, led by the Journal of the American Society of Nephrology (n=16) and Kidney International (n=16). The majority (83.7%) of T100 articles were published by teams involving ≥3 authors. T100 articles originated from 15 countries, led by the USA (n=81) followed by Italy (n=9). Among the T100 articles, 69 were clinical research, 25 were basic science, 21 were reviews, 5 were meta-analyses and 3 were clinical guidelines. Most clinical articles (55%) included patients with any cause of AKI, followed by the specific causes of contrast-induced AKI (25%) and cardiac surgery-induced AKI (15%). CONCLUSIONS: This study provides a historical perspective on the scientific progress on AKI, and highlights areas of research requiring further investigations and developments.

Improved Anatomical Specificity of Non-invasive Neuro-stimulation by High Frequency (5 MHz) Ultrasound.

Low frequency ultrasound (<1 MHz) has been demonstrated to be a promising approach for non-invasive neuro-stimulation. However, the focal width is limited to be half centimeter scale. Minimizing the stimulation region with higher frequency ultrasound will provide a great opportunity to expand its application. This study first time examines the feasibility of using high frequency (5 MHz) ultrasound to achieve neuro-stimulation in brain, and verifies the anatomical specificity of neuro-stimulation in vivo. 1 MHz and 5 MHz ultrasound stimulation were evaluated in the same group of mice. Electromyography (EMG) collected from tail muscles together with the motion response videos were analyzed for evaluating the stimulation effects. Our results indicate that 5 MHz ultrasound can successfully achieve neuro-stimulation. The equivalent diameter (ED) of the stimulation region with 5 MHz ultrasound (0.29 ± 0.08 mm) is significantly smaller than that with 1 MHz (0.83 ± 0.11 mm). The response latency of 5 MHz ultrasound (45 ± 31 ms) is also shorter than that of 1 MHz ultrasound (208 ± 111 ms). Consequently, high frequency (5 MHz) ultrasound can successfully activate the brain circuits in mice. It provides a smaller stimulation region, which offers improved anatomical specificity for neuro-stimulation in a non-invasive manner.

Oct-4 is associated with gastric cancer progression and prognosis.

AIM: To investigate the clinical significance of Oct-4 in the development and progression of gastric cancer. METHODS: Immunohistochemistry was used to analyze Oct-4 expression in 412 gastric cancer cases. Oct-4 protein levels were upregulated in gastric cancer tissues compared with adjacent noncancerous tissues. RESULTS: Positive expression of Oct-4 correlated with age, depth of invasion, Lauren classification, lymph node metastasis, distant metastasis, and TNM stage. In stages I, II, and III, the 5-year survival rate of patients with high expression of Oct-4 was significantly lower than that in patients with low expression of Oct-4. In stage IV, Oct-4 expression did not correlate with the 5-year survival rate. Furthermore, multivariate analysis suggested that the depth of invasion, lymph node metastasis, distant metastasis, TNM stage, and upregulation of Oct-4 were independent prognostic factors of gastric cancer. CONCLUSION: Oct-4 protein is a useful marker in predicting tumor progression and prognosis.

New application of an old drug: Antitumor activity and mechanisms of doxycycline in small cell lung cancer.

Small cell lung cancer (SCLC) remains one of the most aggressive tumors with a poor prognosis. The clinical outcome of SCLC patients has reached its plateau with the existing standard treatment and thus new therapies are urgently required. Accumulating evidences have indicated that doxycycline, a commonly used antibiotic, has antitumor activity against several malignancies. However, whether doxycycline has antitumor activity in SCLC and its underlying mechanisms remain unclear. Our investigation demonstrated that doxycycline could significantly inhibit the proliferation and colony formulation of SCLC cells (p<0.05). Furthermore, both Hoechst 33258 dye staining and TUNEL assays indicated that doxycycline could induce remarkable apoptosis of H446 cells in a concentration-dependent manner. RT-PCR and western blot assays proved that apoptosis induction effect of doxycycline was achieved via inducing the expression of caspase-3 and bax, as well as attenuating the expression of survivin and bcl-2. Moreover, the wound healing assay and Transwell assay indicated that doxycycline could significantly suppress the migration and invasion of H446 cells in a concentration-dependent manner (p<0.05). ELISA assay proved that the inhibitory effect of doxycycline on the migration and invasion of H446 cells was achieved via decreasing the secretion of MMP-2, MMP-9 and VEGF, as well as increasing the secretion of TIMP-2. Taken together, doxycycline dose-dependently suppressed the proliferation, colony formulation, migration and invasion of SCLC cells, as well as induced apoptosis. These findings encourage further investigations on the potential of doxycycline as a candidate drug for the treatment of SCLC.

Pulse Pressure Variation Adjusted by Respiratory Changes in Pleural Pressure, Rather Than by Tidal Volume, Reliably Predicts Fluid Responsiveness in Patients With Acute Respiratory Distress Syndrome.

OBJECTIVES: 1) To evaluate the ability of pulse pressure variation adjusted by respiratory changes in pleural pressure to predict fluid responsiveness compared with pulse pressure variation alone. 2) To identify factors explaining the poor performance of pulse pressure variation in acute respiratory distress syndrome. DESIGN: Prospective study. SETTING: Forty-bed university hospital general ICU. PATIENTS: Ninety-six mechanically ventilated acute respiratory distress syndrome patients requiring fluid challenge. INTERVENTIONS: Fluid challenge, 500 mL saline over 20 minutes. MEASUREMENTS AND MAIN RESULTS: Before fluid challenge, esophageal pressure was measured at the end-inspiratory and end-expiratory occlusions. Change in pleural pressure was calculated as the difference between esophageal pressure measured at end-inspiratory and end-expiratory occlusions. Hemodynamic measurements were obtained before and after the fluid challenge. Patients were ventilated with tidal volume 7.0 ± 0.8 mL/kg predicted body weight. The fluids increased cardiac output by greater than 15% in 52 patients (responders). Adjusting pulse pressure variation for changes in pleural pressure (area under the receiver operating characteristic curve, 0.94 [0.88-0.98]) and the ratio of chest wall elastance to total respiratory system elastance (area under the receiver operating characteristic curve, 0.93 [0.88-0.98]) predicted fluid responsiveness better than pulse pressure variation (area under the receiver operating characteristic curve, 0.78 [0.69-0.86]; all p < 0.01). The gray zone approach identified a range of pulse pressure variation/changes in pleural pressure values (1.94-2.1) in 3.1% of patients for whom fluid responsiveness could not be predicted reliably. On logistic regression analysis, two independent factors affected the correct classification of fluid responsiveness at a 12% pulse pressure variation cutoff: tidal volume (adjusted odds ratio 1.57/50 mL; 95% CI, 1.05-2.34; p = 0.027) and chest wall elastance/respiratory system elastance (adjusted odds ratio, 2.035/0.1 unit; 95% CI, 1.36-3.06; p = 0.001). In patients with chest wall elastance/respiratory system elastance above the median (0.28), pulse pressure variation area under the receiver operating characteristic curve was 0.94 (95% CI, 0.84-0.99) compared with 0.76 (95% CI, 0.61-0.87) otherwise (p = 0.02). CONCLUSIONS: In acute respiratory distress syndrome patients, pulse pressure variation adjusted by changes in pleural pressure is a reliable fluid responsiveness predictor despite the low tidal volume (< 8 mL/kg). The poor predictive ability of pulse pressure variation in acute respiratory distress syndrome patients is more related to low chest wall elastance/respiratory system elastance ratios than to a low tidal volume.

Genetically-reduced serum ACE activity might be a causal risk factor for obstructive sleep apnea syndrome: A meta-analysis.

We meta-analytically summarized the associations of angiotensin converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism with ACE activity and obstructive sleep apnea syndrome (OSAS) to see whether ACE activity is causally associated with OSAS. Literature search and data abstraction were done in duplicate. Sixteen articles including 2060 OSAS patients and 1878 controls were summarized. Overall, no significance was observed for the association of I/D polymorphism with OSAS, whereas carriers of II genotype (weighted mean difference or WMD, 95% confidence interval or CI, P: -11.976, -17.168 to -6.783, <0.001) or I allele (-9.842, -14.766 to -4.918, <0.001) had a lower level of serum ACE activity compared with DD genotype carriers, respectively. In subgroup analyses, carriers of II genotype were 3.806 times more likely to develop OSAS (95% CI, P: 1.865 to 7.765, <0.001) in OSAS patients with hypertension, without heterogeneity. Mendelian randomization analysis indicated there was 37.4% (95% CI: 1.115 to 3.142) and 32.4% (1.106 to 2.845) increased risk of OSAS by a reduction of 1 U/L in ACE activity for the II genotype and I allele carriers versus DD genotype carriers, respectively. There was no observable publication bias. Collectively, genetically-reduced serum ACE activity might be a causal risk factor for OSAS.