Randomized Double-Blind Study of the Effect of Injectate Temperature on Intrathecal Bupivacaine Dose Requirement in Spinal Anesthesia for Cesarean Delivery.

BACKGROUND: Increasing the temperature of intrathecal local anesthetics has been shown to increase the speed of onset and block height of spinal anesthesia. However, how this influences dose requirement has not been fully quantified. The aim of this study was to determine and compare the effective dose for anesthesia for cesarean delivery in 50% of patients (ED50) of intrathecal bupivacaine given at temperatures of 37 °C (body temperature) or 24 °C (room temperature). METHODS: Eighty healthy parturients having elective cesarean delivery under combined spinal-epidural anesthesia were randomly assigned to receive intrathecal hyperbaric bupivacaine stored at 37 °C (body temperature group) or 24 °C (room temperature group). The first subject in each group received a bupivacaine dose of 10 mg. The dose for each subsequent subject in each group was varied with an increment or decrement of 1 mg based on the response (effective or noneffective) of the previous subject. Patients for whom the dose was noneffective received epidural supplementation after data collection with lidocaine 2% as required until anesthesia was sufficient for surgery. Values for ED50 were calculated using modified up-down sequential analysis with probit analysis applied as a backup sensitivity analysis. These values were compared and the relative mean potency was calculated. RESULTS: The ED50 (mean [95% confidence interval, CI]) of intrathecal hyperbaric bupivacaine was lower in the body temperature group (6.7 [5.7-7.6] mg) compared with the room temperature group (8.1 [7.7-8.6] mg) (P < .05). The relative potency ratio for intrathecal bupivacaine for the room temperature group versus the body temperature group was 0.84 (95% CI, 0.77-0.93). CONCLUSIONS: Warming hyperbaric bupivacaine to body temperature reduced the dose requirement for spinal anesthesia for cesarean delivery by approximately 16% (95% CI, 7%-23%).

Neuron-derived exosomes mediate sevoflurane-induced neurotoxicity in neonatal mice via transferring lncRNA Gas5 and promoting M1 polarization of microglia.

Sevoflurane exposure during rapid brain development induces neuronal apoptosis and causes memory and cognitive deficits in neonatal mice. Exosomes that transfer genetic materials including long non-coding RNAs (lncRNAs) between cells play a critical role in intercellular communication. However, the lncRNAs found in exosomes derived from neurons treated with sevoflurane and their potential role in promoting neurotoxicity remain unknown. In this study, we investigated the role of cross-talk of newborn mouse neurons with microglial cells in sevoflurane-induced neurotoxicity. Mouse hippocampal neuronal HT22 cells were exposed to sevoflurane, and then co-cultured with BV2 microglial cells. We showed that sevoflurane treatment markedly increased the expression of the lncRNA growth arrest-specific 5 (Gas5) in neuron-derived extracellular vesicles, which inhibited neuronal proliferation and induced neuronal apoptosis by promoting M1 polarization of microglia and the release of inflammatory cytokines. We further revealed that the exosomal lncRNA Gas5 significantly upregulated Foxo3 as a competitive endogenous RNA of miR-212-3p in BV2 cells, and activated the NF-κB pathway to promote M1 microglial polarization and the secretion of inflammatory cytokines, thereby exacerbating neuronal damage. In neonatal mice, intracranial injection of the exosomes derived from sevoflurane-treated neurons into the bilateral hippocampi significantly increased the proportion of M1 microglia, inhibited neuronal proliferation and promoted apoptosis, ultimately leading to neurotoxicity. Similar results were observed in vitro in BV2 cells treated with the CM from HT22 cells after sevoflurane exposure. We conclude that sevoflurane induces the transfer of lncRNA Gas5-containing exosomes from neurons, which in turn regulates the M1 polarization of microglia and contributes to neurotoxicity. Thus, modulating the expression of lncRNA Gas5 or the secretion of exosomes could be a strategy for addressing sevoflurane-induced neurotoxicity.

Determination of the 50% and 95% Effective Dose of Remimazolam Combined with Propofol for Intravenous Sedation During Day-Surgery Hysteroscopy.

Purpose: Remimazolam has demonstrated the potential as a valuable medication for procedural sedation. However, there were some shortcomings for higher doses of remimazolam during hysteroscopy in spite of less frequent adverse events. The aim of this study was to find the 50% and 95% effective dose (ED50 and ED95) of remimazolam when combined with propofol for intravenous sedation during day-surgery hysteroscopy. Patients and Methods: Patients were randomly assigned evenly (20 per group) to one of five different dosage of remimazolam: group A (0.05mg/kg), group B (0.075mg/kg), group C (0.1mg/kg), group D (0.125mg/kg) or group E (0.15mg/kg). Intravenous injection of sufentanil 0.1µg/kg was administered before sedative medication. Intravenous anesthesia was commenced with remimazolam. Subsequently, propofol was administered at 1mg/kg and maintained at 6mg/kg/h. Success was defined when the patient did not move during cervical dilation, had sufficient sedation as judged by SE <60 and no requirement for rescue doses. The success rate, induce and average dosage of propofol, the induction time, total surgery time, recovery time, and adverse events were recorded. Estimate of ED50 and ED95 with 95% confidence interval (CI) was performed by probit regression. Results: The mean (95% CI) values for ED50 and ED95 of remimazolam in patients were 0.09 (0.08-0.11) mg/kg and 0.21 (0.16-0.35) mg/kg, respectively. There was no difference in the induction time, total surgery time, and recovery time among groups. No serious adverse events occurred in all patients. Conclusion: The dose-response effects of remimazolam were evaluated for intravenous sedation during hysteroscopy. A combination of remimazolam and propofol was recommended to produce stabler sedation, reduce the total dosage and have less effect on cardiovascular and respiratory depression.

The Involvement of CaV1.2 in Estrogenic Modulation of Morphine Antinociception in Rats Under Uterine Cervix Pain.

BACKGROUND: Morphine is one of the preferred drugs for the clinical treatment of pain. Both clinical and preclinical studies have reported sexual dimorphism in morphine analgesia. Different circulating levels of estrogen could be involved in sex differences in response to morphine analgesia. In our previous research, we found that capsaicin injection into the cervix of rats caused acute visceral pain that could be relieved by morphine. The role of estrogen in morphine analgesia in rats under uterine cervix pain and its underlying mechanisms remain to be explored. OBJECTIVES: The present study aims to investigate the effect of estrogen on morphine analgesia and its underlying mechanism in rats under uterine cervix pain. STUDY DESIGN: Controlled animal study. SETTING: University laboratory. METHODS: First, we compared the analgesic effect of morphine in ovariectomized rats with uterine cervix pain with or without estrogen replacement. Then, the changes in the expression of opioid receptors and L-type voltage-gated calcium channels (L-type-VGCC, LTCC) at the spinal level were detected by real-time quantitative polymerase chain reaction. Finally, we investigated the effect of the manipulation of spinal LTCC (L-type CaV1.2 calcium channel, L-type CaV1.3 calcium channel) on the estrogen-mediated inhibition of morphine analgesia. RESULTS: Our study shows that morphine antinociception is  diminished in rats with uterine cervix pain that are treated with estrogen. Estrogen treatment increases the expression of spinal CaV1.2 and CaV1.3, while only anti-CaV1.2 treatment impaired estrogenic suppression of morphine antinociception. LIMITATIONS: More underlying mechanisms of the role of spinal CaV1.2 in modulating estrogen-mediated inhibition of morphine analgesia need to be explored in future research. CONCLUSIONS: This is the first evidence that spinal CaV1.2 is involved in estrogenic modulation of morphine antinociception in rats under uterine cervix pain. Our results will provide new ideas and references for estrogen-related differential prescription of opioids.

Incidence of oxygen desaturation using a high-flow nasal cannula versus a facemask during flexible bronchoscopy in patients at risk of hypoxemia: a randomised controlled trial.

BACKGROUND: Patients with obstructive sleep apnoea (OSA), male sex, obesity, older age or hypertension are prone to hypoxemia during flexible bronchoscopy. This study investigated whether using a high-flow nasal cannula (HFNC) could reduce the incidence of oxygen desaturation during bronchoscopy under deep sedation in patients at risk of hypoxemia. METHODS: A total of 176 patients at risk of hypoxemia who underwent flexible bronchoscopy under deep sedation were randomly assigned to two groups: the HFNC group (humidified oxygen was supplied via a high-flow nasal cannula at a rate of 60 L/min and a concentration of 100%, n = 87) and the facemask group (oxygen was supplied via a tight-fitting facemask at a rate of 6 L/min and a concentration of 100%, n = 89). RESULTS: Oxygen desaturation occurred in 4 (4.6%) patients in the HFNC group and 26 (29.2%) patients in the facemask group (P < 0.001). The facemask group required more jaw thrust manoeuvres than the HFNC group (43[48.3%] vs. 5[5.7%], P < 0.001). 8 patients (9.0%) in the facemask group and none in the HFNC group required bag-mask ventilation (P = 0.012). CONCLUSION: The use of an HFNC can reduce the incidence of oxygen desaturation and the requirement for airway intervention in patients at risk of hypoxemia during flexible bronchoscopy under deep sedation. TRIAL REGISTRATION: www.chiCTR.org.cn Identifier: ChiCTR2100044105. Registered 11/03/2021.

Estrogen modulation of visceral pain.

It is commonly accepted that females and males differ in their experience of pain. Gender differences have been found in the prevalence and severity of pain in both clinical and animal studies. Sex-related hormones are found to be involved in pain transmission and have critical effects on visceral pain sensitivity. Studies have pointed out the idea that serum estrogen is closely related to visceral nociceptive sensitivity. This review aims to summarize the literature relating to the role of estrogen in modulating visceral pain with emphasis on deciphering the potential central and peripheral mechanisms.

Plasmid-based generation of neural cells from human fibroblasts using non-integrating episomal vectors.

Differentiation of human fibroblasts into functional neurons depends on the introduction of viral-mediated transcription factors, which present risks of viral gene integration and tumorigenicity. In recent years, although some studies have been successful in directly inducing neurons through sustained expression of small molecule compounds, they have only been shown to be effective on mouse-derived cells. Thus, herein we delivered vectors containing Epstein-Barr virus-derived oriP/Epstein-Barr nuclear antigen 1 encoding the neuronal transcription factor, Ascl1, the neuron-specific microRNA, miR124, and a small hairpin directed against p53, into human fibroblasts. Cells were incubated in a neuron-inducing culture medium. Immunofluorescence staining was used to detect Tuj-1, microtubule-associated protein 2, neuron-specific nucleoprotein NeuN and nerve cell adhesion molecules in the induced cells. The proportion of Tuj1-positive cells was up to 36.7% after induction for 11 days. From day 21, these induced neurons showed neuron-specific expression patterns of microtubule-associated protein 2, NeuN and neural cell adhesion molecule. Our approach is a simple, plasmid-based process that enables direct reprogramming of human fibroblasts into neurons, and provides alternative avenues for disease modeling and neurodegenerative medicine.

Secretion of adipocytes and macrophages under conditions of inflammation and/or insulin resistance and effect of adipocytes on preadipocytes under these conditions.

The purpose of the present study was to examine changes in preadipocytes following the coculture of preadipocytes and adipocytes and the effects on the secretion of adipocytes and macrophages following induction of inflammation and insulin resistance. Mature adipocytes and RAW264.7 macrophages were treated with lipopolysaccharide and insulin to establish models of inflammation and insulin resistance, respectively. The mRNA expression levels of IL-6, MCP-1, and TNF-α in all adipocyte treatment groups were significantly greater compared with the control, and that of adiponectin was less (P<0.05). In the RAW264.7 macrophages, the mRNA expression levels of IL-6 and TNF-α were greater than those in the control group (P<0.05). Moreover, the results of this study confirmed that adipocytes and macrophages increased the secretion of inflammatory factors under conditions of induced inflammation and insulin resistance. In addition, 3T3-L1 adipocytes inhibited the proliferation and differentiation of preadipocytes when cocultured with adipocytes under conditions of inflammation and/or insulin resistance, and the phenotype of preadipocytes did not change.

[Heat-shock protein 70 may be a putative endogenous ligand of Toll-like receptor-4 of human monocytes].

OBJECTIVE: To explore the relation between human heat shock protein 70 (HSP70) and Toll-like receptor-4 (TLR4) in human monocytes. METHODS: Periphery blood mononuclear cells were isolated from the samples of healthy blood donors' whole blood and monocytes were prepared and cultured. HSP70 of the final concentrations of 2.5 microg/ml, 5.0 microg/ml, 7.5 microg/ml, and 10 microg/ml respectively was added; 6 hours later the concentration of TNF-alpha in the supernatant was detected. Another monocytes were cultured and HSP70 of the final concentration of 5.0 microg/ml was added and the concentrations of NF-kappaB were detected 0, 30, 60, and 120 minutes later respectively. TLR4 blocker of the final concentrations of 5 microg/ml, 20 microg/ml, and 30 microg/ml respectively was added into another culture for 30 minutes and 5.0 microg/ml HSP70 was added, then immunochemistry was used to detect the concentration of NF-kappaB 120 minutes after ELISA was used to detect the concentration of and TNF-alpha 8 hours later. In order to examine the influence of HSP70 on the TLR4 in the cytomembrane of monocytes, HSP70 of the final concentration of 5.0 microg/ml was added into the culture of monocytes for 0, 30, 60, and 120 minutes respectively then flow cytometry was used to detect the mean fluorescence intensity (MFI) of TLR4. RESULTS: HSP70 stimulation increased the TNF-a concentration in the supernatant dose-dependently. The percentages of NF-kappaB positive monocytes were 38 +/- 6, 67 +/- 12, and 54 +/- 12 30 min, 60 min, 120 min after HSP70 stimulation, all significantly higher than that at the beginning of experiment (17 +/- 6, P < 0.05, P < 0.01, and P < 0.01). The percentages of NF-kappaB positive monocytes were 39% +/- 4%, 32% +/- 6%, and 28% +/- 6% 120 minutes after anti-TLR4 mAb stimulation, all significantly lower than that of the control group (67% +/- 12%, all P < 0.05). TLR4 blocker of different concentrations significantly inhibited the TNF-alpha secretion by the monocytes (all P < 0.05). The MFI of TLR4 in the cytomembrane of monocyte was significantly down-regulated 60 minutes, especially 120 minutes, after the HSP70 stimulation in comparison with that before the stimulation (P < 0.05 and P < 0.01). CONCLUSION: TLR4 appears to be involved in HSP70-mediated activation of innate immunity.