Endovascular interventional is an important treatment method for intracranial aneurysms. However, due to the risk of intracranial thrombosis, prophylactic use of antiplatelet drugs is generally required. Clinically, the most commonly used drugs are aspirin and clopidogrel; although the latter can significantly reduce the incidence of thromboembolic complications, there are still some patients with clopidogrel resistance who have ischemic adverse events during antiplatelet therapy. In this study, cohort studies of PubMed, Embase and Cochrane Library Databases were retrieved to compare the efficacy and safety of ticagrelor and clopidogrel in endovascular interventional treatment of intracranial aneurysms. A total of 10 cohort studies involving 1377 patients were included in this study. All patients had intracranial aneurysms and underwent endovascular intervention. Platelet function was measured in four of the studies and switched the patients with clopidogrel resistance to ticagrelor, while the remaining six studies did not test platelet function, but were also treated with ticagrelor or clopidogrel. The results of the study showed that ticagrelor, like clopidogrel, can effectively control thrombotic complications in endovascular interventional patients, and also control the occurrence of ischemic complications in clopidogrel-resistant patients. Ticagrelor, as a novel platelet aggregation inhibitor that can reversibly bind to P2Y12 receptor, can effectively control thromboembolic complications without increasing hemorrhagic complications, and is also effective in patients with clopidogrel resistance. Intracranial aneurysm is one of the most common cerebrovascular diseases, with an incidence of approximately 2–7% in adults. With the extension of human lifespan and the advances in detection methods, the prevalence of intracranial aneurysms has notably increased ,2,3,4. TAntiplatelet therapy is a crucial component of endovascular treatment for intracranial aneurysms. Current evidence reveals that proper preoperative and postoperative antiplatelet therapy can significantly reduce thromboembolic events. Currently, the preferred antiplatelet therapy drugs are mainly aspirin and clopidogrel. Clopidogrel is a thiophene pyridine antiplatelet drug that can inhibit platelet aggregation by generating active mercaptan metabolites under the catalysis of liver cytochrome P450 enzyme, which selectively and irreversibly bind to the P2Y12 receptor on the surface of the platelet membrane, inhibit the ADP-platelet receptor binding and the activation of the ADP-mediated glycoprotein GPIIb/IIIa complex .However, certain patients will still have adverse events of stent thrombosis during long-term dual antiplatelet therapy, which reduce the expected therapeutic effect of interventional treatment as well as the benefits to patients. Previous studies believed that clopidogrel and aspirin resistance were the main causes of ischemic cerebrovascular events after interventional therapy, and clopidogrel resistance was more common ,15. At pThis study was pre-defined and reported according to the preferred reporting items in the System Review and Meta-analysis (PRISMA) guidelines. A systematic literature search of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) from inception to 4 May 2022 was conducted by two independent investigators; the following search terms were employed: (Aneurysm [Title/Abstract]) AND (Clopidogrel OR SC 25989C OR SC 25990C OR SR 25989 OR Iscover OR PCR 4099 OR PCR-4099 OR Plavix [Title/Abstract]) AND cyclopropyl)amino)-5-(propylthio)-3H-(1-3)-triazolopyrimidin-3-yl)-5-(2-hydroxyethoxy)cyclopentane-1,2-diol [Title/Abstract]). In addition, the reference lists of relevant articles were further manually and independently searched to filter eligible studies.The inclusion criteria were set as follows: (1) Study type: the study should be randomized controlled trials (RCT), a case control study or a cohort study. (2) Language restriction: English. (3) participants: patients who received intracranial aneurysms with endovascular treatment. (4) Intervention: received antiplatelet therapy with clopidogrel or ticagrelor. (5) Outcomes: reports estimate describing hemorrhagic complications or thromboembolism complications.The exclusion criteria were set as follows: (1) Case reports, review or animal experiments. (2) Patients with intracranial aneurysms were not treated with endovascular therapy. (3) Does not report relevant outcomes on hemorrhagic complications or thromboembolism complications.The retrieved studies were further evaluated by two independent researchers based on the inclusion and exclusion criteria mentioned above; in the event of disagreement between the two researchers, the final decision was made by the third researcher. The following information was extracted from the included studies when available: first author, published year, sample size, type of aneurysm, antiplatelet treatment regimens, follow-up time, incidence of thromboembolism complications, hemorrhagic complications and neurologic disability. The risk of bias was assessed with the Cochrane Collaboration’s tool Review Manager version 5.4.1 software program . In detail, a total of 87 articles were initially selected, including 26 from PubMed, 53 from Embase, and 8 from the Cochrane Library database. Of these, 23 were excluded due to duplication, 42 articles were excluded by reading title and abstract of the literature as not meeting the inclusion criteria, and 13 were excluded due to not meeting the inclusion criteria after full text reading; among them, there were 5 reviews, 5 whose valid data could not be extracted, and 3 case reports. Finally, a total of 10 articles were included. When disagreement occurred, Prof. Dr. Gang Chen made the final decision and quality control.p < 0.05. In addition, we performed a subgroup analysis based on whether patients tested for clopidogrel resistance. An inconsistency index statistic (I2) indexwas used to quantifythe degree heterogeneity among the included studies I2 > 50% was considered as substantial heterogeneity, if there was no statistical heterogeneity among the included studies. The fixed-effect model was used for meta-analysis, and if there was statistical heterogeneity among the results, the random-effect model was used for meta-analysis after excluding the influence of obvious clinical heterogeneity. We registered on PROSPERO with the ID number 348494.The statistical analysis of this meta-analysis was performed using the Review Manager 5.4.1 Version software. To evaluate the effects of different antiplatelet quality regimens on hemorrhagic complications, thromboembolism complications and neurologic disability event, the effects model with Hazard Rate (HR) and its 95% confidence interval (CI) were used as evaluation indexes. In the forest map, if the rhombus graph of the combined effect size does not coincide with the invalid line, it indicates that the combined result is statistically significant, and A total of 87 articles were initially retrieved, including 26 from PubMed, 53 from Embase, and 8 from the Cochrane Library database. Of these, 23 were excluded due to duplication, 42 articles were excluded by reading title and abstract of the literature as not meeting the inclusion criteria, and 13 were excluded due to not meeting the inclusion criteria after full text reading; among them, there were 5 reviews, 5 whose valid data could not be extracted, and 3 case reports. Finally, a total of 10 articles were included. All studies were published between 2017 and 2021. Of the 10 studies, 2  were mulp = 0.52). There was no significant heterogeneity across the pooled studies , as shown in In the meta-analysis of perioperative and postoperative application of clopidogrel or ticagrelor in patients with aneurysms after endovascular interventional surgery, 10 studies were included in the thromboembolic complications analysis; 5 ,24,26,30p = 0.11). No heterogeneity  was observed in these studies, as shown in In the subgroup analysis, all studies were divided into two groups according to whether the patients had platelet function assays, of which 4 ,23,28,29p = 0.66). NO heterogeneity  was observed in these studies, as shown in A total of 7 ,27,28,30p = 0.66), but the results were highly heterogeneous , possibly due to the fact that there were too few studies included, as shown in Subgroup analysis showed that only 2 ,28 studip = 0.55). NO heterogeneity  was observed in these studies, as shown in A total of 4 ,27,29,30p = 0.910); thromboembolism complications; platelet function test subgroup (p = 0.416); no platelet function test subgroup (p = 0.065); neurologic disability (p = 0.881).Sensitivity analysis was performed on each outcome indicator of the ticagrelor group and the clopidogrel group, and the studies were removed one by one to recombine the data; the effect model of these meta-analysis results did not change, suggesting that the results were stable. Publication bias was detected based on the outcomes of ticagrelor and clopidogrel groups. Due to the limited number of included studies, Egger’s test was performed on Stata16.0 software; the results show there was no significant publication bias between the studies. Hemorrhagic complications (With the advances in technology, the treatment of intracranial aneurysm has made remarkable progress. Intracranial aneurysm interventional embolization has become one of the main treatment methods. Its characteristics of small trauma, quick recovery and reliable efficacy play a significant role in accelerating the rehabilitation and improving the prognosis of patients. At present, the main intravascular interventional therapy methods include coiling alone, balloon-assisted coiling, stent-assisted coiling and a blood-flow guidance device. Compared with simple embolization and balloon-assisted embolization, stent-assisted embolization technology can greatly improve the indications for the treatment of cerebral aneurysm and reduce the recurrence rate. However, the incidence of perioperative thromboembolic events in patients with stent-assisted aneurysm embolization is higher than that in patients with simple embolization and balloon-assisted aneurysm embolization, making it necessary for them to take dual antiplatelet drugs for a long time, or even lifelong antiplatelet therapy . As a neClopidogrel and aspirin are the most commonly used antiplatelet drugs, which can significantly reduce the incidence of thrombotic complications after intracranial aneurysm intervention. However, some patients still have ischemic adverse events during the use of clopidogrel and aspirin double antiplatelet therapy; the fact that clopidogrel does not respond to some people is the main reason for the ineffectiveness of antiplatelet therapy, while the polymorphism of clopidogrel metabolic enzyme genes may be one of the factors affecting the antiplatelet effect, mainly including CYP2C19, ABCB1, P2RY12 and CES1, etc. ,34. TherIn the process of antiplatelet aggregation, clopidogrel binding to the P2Y12 receptor is irreversible, which may increase the risk of bleeding complications during medication. Some clinical studies have therefore adopted ticagrelor that can bind reversibly to P2Y12 receptors to improve prognosis ,37. In aThe results of this meta-analysis showed that ticagrelor had the same efficacy as clopidogrel in 6 cohort studies of interventional aneurysm therapy without platelet function test, and could effectively control patients’ thrombosis complications without increasing the incidence of hemorrhagic complications. In 4 studies with clopidogrel resistance, ticagrelor also reduced the incidence of thrombotic complications as effectively as clopidogrel did in patients without clopidogrel resistance in platelet function. In addition, a number of single-arm trials have demonstrated the efficacy of ticagrelor in antiplatelet therapy after stenting and flow diverter procedures ,38,39. SHowever, this meta-analysis also has limitations that cannot be ignored. First, our data were based on 10 limited clinical studies, only 4 of which measured platelet function and compared the efficacy of ticagrelor. Although heterogeneity was not found in most outcomes, there was a high level of heterogeneity in hemorrhagic complications, which may be due to the small number of studies included. Further studies would be needed for comprehensive analysis regarding hemorrhagic complications. Additionally, in this study, we have set the inclusion/exclusion criteria, in which age, gender, and area of study are not considered. However, case reports, review and animal experiments were excluded. Secondly, most of the studies included in this paper were retrospective studies, and only one was a randomized controlled study, which may also be the reason for the heterogeneity among the studies. In addition, some studies provided too short follow-up results, among which the shortest follow-up time was only 1 month.In summary, ticagrelor can effectively control thromboembolism complications without increasing hemorrhagic complications during perioperative and postoperative interventional aneurysm therapy, and its efficacy is also significant in clopidogrel-resistant patients. However, there are still limitations in this meta-analysis, and the conclusions of this study still need more relevant clinical studies with a reasonable design, rigorous execution and a large sample size to further verify.


Due to the rate of occurrence of neonatal hypoxia-ischemia, its neuronal sequelae, and the lack of effective therapies, the development of new neuroprotective strategies is required. Polyphenols (including resveratrol) are molecules whose anti-apoptotic, anti-inflammatory, and anti-oxidative properties could be effective against the damage induced by neonatal hypoxia-ischemia. In this review article, very recent data concerning the neuroprotective role of polyphenols and the mechanisms at play are detailed, including a boost in brain energy metabolism. The results obtained with innovative approaches, such as maternal supplementation at nutritional doses, suggest that polyphenols could be a promising prophylactic treatment for neonatal hypoxia-ischemia. This process induces a drastic drop in the production of adenosine triphosphate (ATP), which leads to a failure of the sodium/potassium ATP-dependent pump (Na+/K+ATPase) [2+ and Na+ into the cell [Neonatal hypoxia-ischemia (HI) is a major public health problem, both in terms of its occurrence (in 1% to 6% of births in developed countries) and its subsequent adverse effects, such as lethality, cognitive disorders, and/or motor disabilities. It usually results from a prolapse of the umbilical cord, a uterine rupture, or maternal hypotension. The disruption of a newborn’s cerebral blood flow is the primary cause of brain injury. The pathophysiology of neonatal HI is characterized by a succession of stages . At the 2+ entry is deleterious and leads to cerebral edema and microvascular damage, resulting in apoptosis or necrosis, depending on the severity of the HI episode. Necrosis occurs in very severe conditions of neonatal HI [This Canatal HI . It causnatal HI . In turnIf HI is less severe, cells will undergo apoptosis, with preservation of the membrane and without additional inflammation . Reperfu2 that is induced by the transition from fetal to neonatal life [2+, and reacts with peroxides to form free radicals, increasing neuronal tissue damage [After the latency phase, a second energy deficit occurs. It is mainly characterized by oxidative stress and inflammation. The exacerbated production of free radicals is responsible for oxidative stress, which causes damage to the membranes of neurons and leads to necrosis or apoptosis. This oxidative stress is particularly deleterious for a newborn’s brain , due to tal life . Newborntal life . In addie damage . 2+ and Na+. The necrosis and apoptosis resulting from these two successive energy deficits lead to neuronal death, which is responsible for sensorimotor and cognitive deficits. Excitotoxicity is also characteristic of this step, due to an excess of extracellular neurotransmitters, in particular glutamate, just as during the first energy deficit. Glutamate overstimulates its receptors, inducing, for the second time, a massive influx of CaTreatment of neonatal HI is primarily symptomatic and is essentially based on maintaining fluids, electrolytes, and respiratory homeostasis. The only interventional therapy that is currently applied is moderate therapeutic hypothermia . HoweverIn writing this review, the PubMed database was screened with the following terms: “neonatal hypoxia-ischemia” (5305 results) and “neuroprotection” (coupled with NHI: 1478 results). To identify articles referring specifically to the topic of our review, we used the term “resveratrol” (coupled with NHI: 15 results) and the term “polyphenols” (coupled with NHI: 19 results). Among the articles identified in the last two searches, only the studies carried out in vivo were considered (n = 17).Resveratrol  is a natural non-flavonoid polyphenol belonging to the stilbene family. Stilbenes are involved in plant defense responses and demonstrate protective properties against plant fungal pathogens and nematodes. RSV is formed from phenylalanine through the action of a key enzyme, the stilbene synthase, which couples 4-hydroxycoumaryl-CoA and three molecules of malonyl-CoA. The resulting RSV molecule consists of two aromatic rings that are connected by a methylenic bridge . It exisAlthough RSV is the most studied of the polyphenols, a scientific interest in some of its derivatives, such as pterostilbene  and ε-viniferin (VNF), is emerging, due to their potentially better bioavailability. Surprisingly, however, few previous studies focused on the effects of piceatannol , whose greater bioavailability that of RSV has been proven . StructuThe neuroprotection of RSV and some of its derivatives  has been+)-dependent deacetylase, which would induce an inhibition of the transcription factor nuclear factor-kappa B (NF-κB) via a negative regulation of the signaling pathway involving the extracellular signal-regulated kinase 1 and 2/mitogen-activated protein kinase (Erk1/2 MAPK) complex. Through this pathway, RSV (pre-treatment and post-treatment) causes an overexpression of the anti-apoptotic gene B-cell lymphoma 2 (Bcl2) and a decrease in the expression of the pro-apoptotic gene Bcl-2–associated X (Bax), as well a decrease in the metalloproteases [2+ levels is responsible for an increase in calpain activities, resulting in the degradation of spectrin, microtubule, and neurofilament proteins. Their high activity disrupts intracellular axonal transport and membrane functions that are involved in the stability of dendritic and axonal processes [The anti-apoptotic properties of RSV require the activation of the silent mating-type information regulation 2 homolog (SIRT1), a nicotine adenine dinucleotide , which are involved in the oxidative damage of macromolecules, such as nucleic acids, proteins, and lipids, which can lead to cell death [During the reperfusion period after a neonatal HI insult, the abrupt reestablishment of the Oll death . This oxll death ,34,35. Rll death . These rll death . PGC-1α ll death . Its act2−) to hydrogen peroxide (H2O2), while GPx and CAT catalyze the reduction of H2O2 to H2O [In another study, using P14 rats as a model of neonatal HI, the administration of RSV (20 mg/kg or 40 mg/kg for seven consecutive days prior to the induction of HI) reduced oxidative stress, in part by increasing the expression of glutathione peroxidase (GPx), SOD2, and catalase (CAT) via the nuclear factor erythroid 2 related factor 2/heme oxygenase 1 (Nrf2/HO-1) pathway just after the HI accident . SOD2 al2 to H2O . The dir2 to H2O ,42. Thes2 to H2O .Inflammation is an important contributor to brain damage that is induced by HI. The anti-inflammatory properties of RSV involve several signaling pathways , includiOxidative stress ,56 and i2) were quite similar, the duration of hypoxia varied from 45 min to 2.5 h. In all these studies, RSV administration was neuroprotective, showing a decrease in oxidative stress [Different studies have evaluated the neuroprotective effect of RSV through a preventive strategy: e.g., RSV being administrated to pups before the HI event. All of these studies are summarized in e stress ,38,62, ae stress ,33,38, ae stress ,27, lead2/92% N2 [2/90% N2 , during 1 h. In all three studies, memory was evaluated using the Morris water maze. All data showed that RSV reversed HI-induced learning and memory impairments. Moreover, even if the Morris water maze was not performed at the same age (from P28 to P33), mice that were treated with RSV during 14 d  performed as well as mice treated at 0 h, 24 h, and 48 h after HI . Those results highlighted that a lower dose administered during a longer period can be as neuroprotective as a higher dose administered during a shorter time. Moreover, as similar neuroprotection by RSV is provided by i.p. injection and force-feeding, force-feeding should be preferred.The curative neuroprotective effect of RSV has been tested in five different studies . Greater2/92% N2 ,65, or 1Altogether, these data suggest that RSV can be a promising therapeutic drug to counteract brain damage that is linked to neonatal HI injury, in both preventive and curative administration. Although these previous studies elegantly demonstrated a neuroprotective role of RSV in the context of neonatal HI, two major limitations precluded an eventual transfer to human newborns: (i) the high doses used, and (ii) the mode of administration, which was mainly by i.p. injection. In order to promote a clinical translation of RSV treatment to offer neuroprotection in a context of HI, the neuroprotective effect of RSV was tested at a very low dose (0.15 mg/kg/d) through maternal supplementation. 2, 20% CO2, and 71% N2, for 90 min. For maternal supplementation, female Wistar rats received an RSV-enriched diet at a dose of 50 mg/kg/d, beginning at P30. Rats were mated at an age between P90 and P100 and the enriched diet was maintained until the offspring were 7 d old. Taking into consideration the intergenerational aspect, the doses used in that study were much lower than the doses used in previous studies with oral gavage or direct i.p. injection. The RSV-enriched maternal diet led to hippocampal neuroprotection of the offspring in the context of asphyxia. The maternal RSV-enriched diet decreased neuronal inflammation in the offspring after asphyxia by decreasing IL-1β and TNFα production. RSV also decreased protein S-100B expression, an increase that can be considered as a marker of brain injury [Isac et al. were the first to test the neuroprotective effect of maternal supplementation with RSV . They din injury .Moreover, the RSV-enriched diet prevented hippocampal damage by acting at the epigenetic level through a decrease in miR-15a expression, which led to accelerated neuronal growth and maturation. Even if the doses used in the study by Isac et al. were lower than those that were usually used, they were still relatively high.+/K+ ATPase). This stimulation of the ANLS may spare glucose, benefiting the pentose phosphate pathway and the neuronal red/ox balance. These studies, which involved maternal supplementation, are summarized in An innovative approach was recently developed to counteract the deleterious effect of neonatal HI. The neuroprotection of a maternal supplementation with RSV was evaluated, as it was in the study by Isac et al. The innovative aspect of this approach was the nutritional consideration, with extremely low doses in the order of what would be found in a standard diet. In that study, dams were supplemented via drinking water with 0.15 mg/kg/d of RSV during different time windows, either before or after the HI event  . If the Although accumulating preclinical studies show a neuroprotective effect of RSV in numerous pathologies—obesity, diabetes, metabolic syndrome, cancer, cardiovascular diseases, and neuronal pathologies including HI—the therapeutic application in humans remains limited due to the short half-life of RSV, its rapid metabolism (into glucuronide and sulfate or methoxy derivatives) and high urinary elimination. The dichotomy between data from preclinical studies and clinical studies has been reviewed previously ,70. DespTo increase the bio-efficacy and neuroprotection through maternal supplementation, the effect of PIC, which is four times more bioavailable than RSV, was tested in rats  Table 4Table 4. Another strategy to increase bio-efficacy is to take advantage of putative synergistic effects of a combination of different polyphenols . An assePolyphenols are produced as needed by plants, but they cannot be synthesized by the human body; the intake of these micronutrients is therefore from the diet. In order to compare and determine an order of magnitude of the doses tested in the studies mentioned above, we evaluated the quantities of elements rich in resveratrol, commonly found in a diet, which should be consumed by a pregnant woman to match the amount administered in animal experiments. Quantities are given for a pregnant woman weighing 70 kg . In contDue to its anti-apoptotic, antioxidant, anti-inflammatory properties, and its ability to stimulate cerebral energy metabolism, RSV is a very good candidate to counteract the deleterious effects of neonatal HI. However, its low bioavailability makes the translation from preclinical studies to human neonates difficult. An increase in polyphenolic bioavailability, in correlation with an increase in bio-efficacy, would be a very interesting avenue for transposing the benefits of RSV to humans. In addition, from the perspective of clinical application, some points should be considered for future studies: (i) the doses used should be low and of the nutritional order; and (ii) the mode of intraperitoneal administration should be abandoned in favor of maternal supplementation. The experimental conditions  should be standardized in order to be able to compare the different conditions among the studies. The overall molecular mechanisms remain to be elucidated. The behavioral assessments of the beneficial effects of preventive administration of polyphenols could be substantiated in order to better understand the mode of action of polyphenolic neuroprotection. More studies on the neuroprotective effects of maternal supplementation with polyphenolic cocktails or plant extracts rich in RSV-derived polyphenols could open new, promising, and innovative avenues for counteracting the deleterious effects of neonatal HI.


In addition, patients treated with ondansetron had a reduced need for vasopressors administration. This study suggests that ondansetron may be recommended as a prophylaxis for hypotension and bradycardia following spinal anaesthesia; the level of evidence was moderate with a high level of heterogeneity.Hypotension induced by spinal anaesthesia is a common clinical complication associated with multiple perioperative adverse events. We conducted a systemic review and meta-analysis to confirm whether ondansetron could alleviate hypotension following spinal anaesthesia. PubMed, Embase, Web of Science, and Cochrane Library were searched to identify eligible randomised controlled trials from their respective database inception dates to 30 September 2022. The primary outcome of the meta-analysis was the incidence of hypotension after spinal anaesthesia. The risk of bias in the included studies was evaluated using the revised Cochrane risk of bias tool for randomised trials (RoB 2.0). Grading of Recommendations, Assessment, Development, and Evaluation was applied to assess the level of certainty. A total of 25 studies were included in this research. The meta-analysis revealed that ondansetron significantly decreased the incidence of hypotension (RR = 0.65, 95% CI 0.53–0.80,  The recommended anaesthetic technique for various surgical procedures, including caesarean section, orthopaedic surgery, and lower abdominal general surgery, is spinal anaesthesia, also known as a subarachnoid block. However, hypotension caused by spinal anaesthesia is a common problem that plagues doctors and patients, occurring in approximately 80% of cases . A reducThe mechanism of hypotension following spinal anaesthesia involves the reduction in vascular resistance caused by the sympathetic block and the activation of the Bezold–Jarisch reflex, leading to vasodilation and hypotension . PeripheThis systematic review and meta-analysis were performed and reported according to the recommendations of the preferred reporting items for systematic reviews and metanalyses. The registration number of the International Prospective Register of Systematic Reviews (PROSPERO) was CRD 42022353540.The electronic databases of Web of Science, PubMed, Cochrane Library, and Embase were systematically searched. The retrieval date was from database establishment to 30 September 2022 without language limitations. The search terms included the following: “ondansetron”, “5-HT3 receptor antagonists”, “5-Hydroxytryptamine3”, “spinal anaesthesia”, “intrathecal anaesthesia”, and “subarachnoid anaesthesia”. Furthermore, the references of the eligible studies were also searched systematically.The eligibility requirements for inclusion were as follows: (1) Participants (P): patients receiving spinal anaesthesia. (2) Intervention (I): trials reporting ondansetron was administered intravenously. (3) Comparison (C): placebo. (4) Outcome (O): trials reporting the incidence of hypotension was one of the outcomes. (5) Study designs (S): randomised controlled trials (RCTs).The following were the exclusion criteria for this research: (1) Combined with other types of anaesthesia, such as epidural and general anaesthesia. (2) Animal studies. (3) Incomplete studies, such as conference abstracts. (4) Ondansetron was administered by other means.First, EndNote was used independently by two authors to exclude the duplicates. Second, they determined whether the trials met the conditions according to the title and abstract. Finally, the full texts of the screened studies were then carefully examined to determine whether they met all the inclusion criteria. Using data from the included studies, the two authors independently retrieved and cross-checked the following information: the author’s name, year of publication, type of surgery, sample size, patients, blinding methods, details of spinal anaesthesia, dosage and timing of ondansetron, and the definition of hypotension. We emailed the corresponding authors of the research where some information was unavailable in the published articles. We sent another email enquiry if there was no response after more than a week.The primary outcome of this study was the incidence of hypotension following spinal anaesthesia.  Secondary outcomes included the incidence of bradycardia, the use of vasopressor administration, and the dosage of ephedrine. If different doses or different types of ondansetron were studied, we combined the dichotomous variables for the meta-analysis. In the case of continuous variables, we analysed the data for different groups.A revised Cochrane risk of bias tool for randomised trials (RoB 2.0) was used to assess the risk of bias in the included studies. The risk of bias table included bias from the process of randomisation, bias due to deviations from the expected interventions, bias from missing data, bias from the measurement of the outcome, and bias from the selection of the reported results. Each trial was assessed as either high risk, some concerns, or low risk. The degree of confidence was assessed utilizing the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE). Accordingly, the level of certainty was categorised as very low, low, moderate, or high.p-value was <0.05. The number needed to treat (NNT) was calculated for statistically significant outcomes. The heterogeneity in the trials was examined utilizing the I2 statistic, wherein I2 > 50% was defined as “highly heterogeneous”. Clinical and methodological issues were shown to be the primary causes for high clinical heterogeneity. Consequently, a random-effects model was utilised even in studies with low I2 values.The meta-analysis was performed using the Review Manager 5.3  statistical software and Stata version 12.0 . The pooled risk ratio (RR) and 95% confidence intervals (CIs) for dichotomous outcomes were calculated. For continuous data, the mean differences (MD) and 95% CIs were evaluated. Statistical significance was considered to be achieved when the Subgroup analyses were performed according to the different dosages of ondansetron (≤4 mg vs. >4 mg) and type of surgeries (caesarean section vs. non-caesarean section). For the trials that did not report the type of surgery and clearly did not belong to caesarean section , we analysed them in the non-caesarean section group. Funnel plots and Egger’s test were employed to assess the publication bias. In addition, a sensitivity analysis was performed to test the stability of the primary outcome.Using TSA software (version 0.9.5.10 beta), we performed a TSA method to control the risk of type I error caused by repeated testing. When the cumulative z-curve crosses the TSA monitoring boundary or enters the required information size line, no further study is required . The risn = 3) [n = 15) [According to the retrieval strategy, a total of 938 related studies were initially obtained from the databases. First, 245 duplicates were excluded, following which, 650 studies were removed once their titles and abstracts were reviewed. To determine whether the remaining 43 studies met the criteria for inclusion, their full texts were carefully analysed. Notably, 18 additional trials were omitted for the following reasons: conference abstracts (n = 3) ,17,18 an[n = 15) ,27,28,29[n = 15) ,48,49,50In total, 25 RCTs comprising 2536 patients (1405 patients in the ondansetron group and 1131 patients in the control group) were analysed. The publication years for these studies were from 2005 to 2021, and the sizes of the samples were within a range of 40–254. The dosage of ondansetron ranged from 2 mg to 12 mg. One study was investigator-blinded , anotherEight trials had a high risk of bias in the “randomisation process”, while five trials had some concerns of bias in the “measurement of the outcome”. Only six trials had a pre-registered protocol, and the “selection of the reported results” was graded as low risk. All the included trials reported the incidence of hypotension. The meta-analysis demonstrated that ondansetron reduces the occurrence of hypotension as compared to the control group, with high heterogeneity , suggesting there was no obvious publication bias , bradycardia , and the need for vasopressor administration rescue  in patients undergoing spinal anaesthesia. According to the TSA, there was sufficient evidence to support the fact that ondansetron prevents hypotension after spinal anaesthesia.In recent years, studies have been conducted on different treatments for hypotension following spinal anaesthesia, such as fluid therapy and vasopressors ,52. HoweNotably, the TSA findings indicated that the information size for supporting the role ondansetron plays was sufficient, meaning that there is no need to spend more resources on clinical trials to investigate its effectiveness. In addition, we evaluated the preventive effect of ondansetron on hypotension by subgroup analysis at different doses (low-dose vs. high-dose) and different surgical types (caesarean section vs. non-caesarean section). The results of the subgroup analyses were consistent with the overall result. However, we did not conduct a meta-analysis for other types of 5-HT3 receptor antagonists due to the insufficient trials. Therefore, to extend this finding to other types of 5-HT3 receptor antagonists, additional high-quality RCTs are required.In addition, we found that patients treated with ondansetron had a lower need for vasopressor administration and a lower dosage of administered ephedrine, which were consistent with previous studies ,12. ThisThere was significant clinical heterogeneity, which may be related to the different patient populations , types of surgery, different dosages of ondansetron, type of spinal anaesthesia and drug, definition of hypotension, and the technique to measure blood pressure. Therefore, a random-effects model was adopted in this meta-analysis. Due to the high level of heterogeneity, the quality of evidence for the primary outcome was moderate.This study had some limitations. First, some included studies did not clearly report the method of randomisation, leading to a decline in study quality. Second, meta-analyses for other types of 5-HT3 receptor antagonists were not conducted due to insufficient data. Third, some included studies did not report the type of surgery, which could lead to potential bias. Finally, definitions of hypotension and bradycardia varied across studies, causing potential bias.This study provided evidence that ondansetron may serve as a clinical option for the prevention of hypotension and bradycardia following spinal anaesthesia. Further research is needed to determine whether the effect is similar for other types of 5-HT3 receptor antagonists.


To explore the efficacy and safety of chlorhexidine oral care in the prevention of ventilator-associated pneumonia (VAP) by means of meta-analysis.  Randomized controlled trials on the effect of chlorhexidine oral care on the incidence of VAP in patients on mechanical ventilation were searched in PubMed, Scopus, Cochrane Library, and Embase from May 1, 2022. Two researchers independently screened and included the study, extracted the data, and evaluated the literature quality. RevMan5.3 software was used for meta-analysis. P=0.04). However, the results showed that the incidence of VAP of low concentration  and high concentration (2%) of chlorhexidine in the intervention group was lower than that in the control group and the difference was statistically significant , P=0.03; RR = 0.41, 95% CI ). There was no significant difference in mortality between the two groups , P=0.87). There was no statistical significance in days ventilated or days in ICU between the two groups , P=0.84; RR = 0.01, 95% CI , P=0.85).  Meta-analysis of 13 included literature studies involving 1533 patients showed that oral care with chlorhexidine solution could reduce the incidence of VAP in patients with mechanical ventilation and the difference was statistically significant ,  Existing evidence shows that chlorhexidine used for oral care of patients with mechanical ventilation can reduce the incidence of VAP, and high concentration of chlorhexidine (2%) or low concentration of chlorhexidine  has a significant effect on the prevention of VAP. Considering the safety of clinical application, it is recommended to use 0.02%, 0.12%, and 0.2% chlorhexidine solution for oral care. Mechanical ventilation can provide essential oxygen supply for patients with respiratory failure due to serious cardiovascular infections and brain trauma, maintain smooth airways of patients, relieve respiratory failure, and provide adequate conditions for patients' treatment . MechaniChlorhexidine as a commonly used broad-spectrum antimicrobial has been widely regarded. Oral care with chlorhexidine nursing solution can reduce oral bacterial colonization and the migration and colonization of microorganisms in the lung. Chlorhexidine gluconate contained in chlorhexidine nursing solution is a broad-spectrum fungicide, which can combine with salivary glycoprotein, reduce tooth surface adsorption protein, and hinder the formation of plaque –14. At pAlthough some systematic studies have shown that chlorhexidine has a positive effect on the prevention of VAP –18, someStudy type: RCT was done with unlimited sample size and limited English literature. Intervention: oral care was performed with chlorhexidine solution in the intervention group, and oral care was performed with normal saline or placebo in the control group. Outcome indicators: the main outcome indicators were the incidence of VAP, and the secondary outcome indicators were mortality, bacterial colonization , pulmonary infection score, mechanical ventilation time, length of hospital stay, oral ulcer, patient satisfaction, etc.The exclusion criteria were as follows: (1) unable to obtain the full text; (2) data cannot be obtained or converted; (3) reviews, single-arm studies, and other non-RCTs; (4) repeated publications; (5) the intervention measures were chlorhexidine combined with other interventions or not used in the oral care literature; (6) infants- and children-based studies.The literature published in PubMed, the Cochrane Library, Scopus, and Embase was systematically searched from the establishment of the database to May 1st, 2022. Meanwhile, literature including conference papers and the references included in the studies was manually searched. The search terms were determined by the combination of mesh terms and entry terms. Terms include endotracheal intubation, dichlorobenzene biguanide hexane, chlorhexidine, VAP, and ventilator-associated pneumonia.Literature screening was completed by 2 researchers independently. First, the literature data were imported into the database using Endnote software to remove duplicate literature. Then, the title and abstract were preliminarily screened by reading. Finally, the full text was read to determine whether the bibliography was included or not. Subsequently, data were extracted by two researchers alone, and the extracted information included the following: (1) the basic information of the literature, such as author, publication year, and country; (2) intervention frequency and intervention measures of the two groups; (3) outcome indicators.The authenticity of RCTs was evaluated by 2 researchers according to the Cochrane Collaboration System Evaluation Manual (version 5.1.0), including selection bias, implementation bias, measurement bias, loss of follow-up bias, reporting bias, and other biases. If there is any dispute between two researchers, the dispute should be settled through negotiation.P < 0.1 and I2 > 50%, the reasons for heterogeneity should be analyzed first, such as whether the design scheme and measurement method are the same. If there is still heterogeneity in the results, the random effect model can be used to calculate the pooled results.RevMan 5.3 software was used for statistical analysis. Hazard ratio (RR) and 95% confidence interval (CI) were used as statistics for categorical variables, and standard mean difference and 95% confidence interval (CI) were used as statistics for continuous variables. The heterogeneity was evaluated. When the heterogeneity test is 485 related literature studies were obtained through preliminary retrieval. After the screening, 13 literature studies were finally included –31.  FigThe 13 included literature studies –31 were F = 0.03, I2 = 45%), so a fixed-effect model was adopted for analysis. The results showed that oral care with chlorhexidine can reduce the incidence of VAP in patients with mechanical ventilation, with a statistically significant difference , P=0.04).Thirteen pieces of literature reported the incidence of VAP, involving 1533 patients with mechanical ventilation, with 786 in the intervention group and 747 in the control group. Heterogeneity test results showed that there was heterogeneity between studies , F < 0.001)  and high-concentration (2%) chlorhexidine VAP in the intervention group was lower than that in the control group. Difference was statistically significant , < 0.001) .P=0.24, I2 = 21%), and the results were still statistically significant , F < 0.001)  .P=0.52, I2 = 0%). There was no significant difference in mortality between the two groups , P=0.54)  .P=0.004, I2 = 53%), so the random effect model was used for analysis, and the results showed that there was no significant difference in mortality between the two groups , P=0.84)  .P=0.82, I2 = 0%), so a fixed-effect model was adopted for analysis. There was no significant difference in the length of ICU stay between the two groups , P=0.85). . .The funnel plot was drawn using VAP incidence as an outcome indicator, and the results showed asymmetry of the funnel plot, suggesting possible publication bias. Then, we performed the sensitivity analysis, As an important means of life support, mechanical ventilation is widely used in the treatment of respiratory diseases, which can relieve hypoxia and carbon dioxide retention. However, mechanical ventilation can lead to a variety of complications such as VAP sepsis, bleeding, and digestive dysfunction, among which VAP is the most common , 33. TheThe results of this study show that the oral care of mechanical ventilation patients with chlorhexidine can significantly reduce the incidence of VAP, and a high concentration of chlorhexidine (2%) or low concentration of chlorhexidine  has a significant effect on the prevention of VAP and there is no significant difference in mortality between the two groups, ventilation time, and ICU stay time. However, studies have shown that long-term use of high concentrations of chlorhexidine may cause some adverse reactions, such as oral mucosa exfoliation, taste change, and tongue coloring . TherefoLimitations of this study: the languages included in the study were limited, only English, and there may be some included parts of publication bias. The literature quality is not high. Among the 13 included studies, only 7 reported allocation hiding, 8 introduced the random grouping method in detail, 7 mentioned the implementation of intervenor blindness, and the other studies did not mention or implement intervenor blindness, which may be interfered with by intervenor subjective factors. The homogeneity of the included studies was not high. Factors such as frequency and method of oral care , the concentration of chlorhexidine in the intervention measures, and physical fitness and cultural environment caused by different countries and regions of subjects may affect the results.Existing evidence shows that chlorhexidine used for oral care of patients with mechanical ventilation can reduce the incidence of VAP, and high concentration of chlorhexidine (2%) or low concentration of chlorhexidine  has a significant effect on the prevention of VAP. Considering the safety of clinical application, it is recommended to use 0.02%, 0.12%, and 0.2% chlorhexidine solution for oral care.


The aim of this study is to assess whether restaging transurethral resection (ReTUR) could be safely replaced with urine cytology (UC) and in-office fiexible cystoscopy in selected T1 non-muscle-invasive bladder cancer (NMIBC).This is an ongoing prospective multicenter trial enrolling patients diagnosed with T1 BC from 5 Italian centers. Patients with a macroscopically incomplete initial resection or absence of detrusor muscle were subjected to ReTUR according to European Association of Urology (EAU) guidelines. Conversely, those with a complete tumor resection at initial TUR underwent UC at 3–4 weeks and in-office fiexible white-light and narrow-band cystoscopy at 4–6 weeks. In case of positive UC, or evidence of recurrence at cystoscopy, ReTUR was performed within 2 weeks. Otherwise, patients started Bacillus Calmette–Guérin (BCG) induction course without ReTUR. The primary endpoint was to determine the feasibility and the clinical utility of not performing ReTUR in selected T1 NMIBC patients. The secondary endpoint was to perform a cost–benefit analysis of this alternative approach.Since May 2020, among 87 patients presenting with T1, 76 patients were enrolled. Nineteen (25%) patients underwent standard ReTUR after initial resection, 10 (13.2%) due to the absence of the detrusor muscle and 9 (11.8%) due to a macroscopically incomplete initial TUR. Overall, 57 (75%) patients initially avoided immediate ReTUR and underwent UC plus in-office flexible cystoscopy. Among them, 38 (66.7%) had no evidence of residual disease and immediately started the BCG induction course. Nineteen patients (33.3%) underwent “salvage” ReTUR due to either positive UC  or suspicious cystoscopy . Considering only the patients who initially avoided the ReTUR, disease recurrence was observed in 10/57. The saving of resource for each safely avoided ReTUR was estimated to be 1,759 €. Considering the entire sample, we estimated a saving of 855 € per patient if compared with the EAU guideline approach.The preliminary results of our trial suggested that ReTUR might be safely avoided in highly selected T1 BC patients with a complete resection at first TUR. Longer follow-up and larger sample size are needed to investigate the long-term oncological outcomes of this alternative approach. Transurethral resection (TUR) and subsequent intravesical Bacillus Calmette–Guérin (BCG) course are the standard treatments in high-risk (HR) NMIBC. However, these patients are characterized by a high risk of both recurrence and progression to MIBC. The European Association of Urology (EAU) guidelines suggest performing a second resection [restaging transurethral resection (ReTUR)] before the BCG induction course within 2–6 weeks from the first resection in case of incomplete initial resection, absence of detrusor muscle (DM) in the pathological specimen . The HuNIRe protocol was approved by the local ethics committees after the approval of the reference center ethics committee (n. 2503 of the 08.05.2020 ICH-010).Since May 2020, consecutive patients with a pathological diagnosis of T1 NMIBC and aged >18 years old were considered as cases of interest. Patients who had a history of BCG instillations or previous or concomitant upper tract urothelial cancer or those with histological variants were excluded. All patients were informed about the rationale and the purpose of the study and signed a written informed consent. Surgeries were performed by experienced urologists. Experienced urologists were defined as urologists who have performed more than 100 TURs. The completeness of the resections was reported by the surgeon at the end of the resection in a dedicated surgical checklist  after 3–4 weeks and in-office flexible white-light and narrow-band imaging (NBI)-enhanced cystoscopy after 4–6 weeks.In case of positive UC or evidence of tumor at cystoscopy, ReTUR was performed within 2 weeks. Alternatively, patients started BCG induction course without undergoing ReTUR. Conversely, patients with NMIBC or no residual tumor on ReTUR or those with no visible residual tumor at 4–6-week cystoscopy underwent 6-week induction course with intravesical BCG followed by standard maintenance scheme, which consisted of weekly intravesical BCG instillations for 3 weeks at 3, 6, 12, 18, 24, 30, and 36 months .Follow-up consisted of cystoscopy and urinary cytology at 3 months followed by cystoscopy and cytology every 3 months for a period of 2 years and every 6 months thereafter. All patients underwent computed tomography of the upper urinary tract after the diagnosis and yearly thereafter . UC was The primary endpoint was to determine the feasibility and the clinical utility of avoiding ReTUR in selected T1 NMIBC patients. Clinical utility was defined as the rate of unnecessary ReTUR avoided, while recurrence is considered as the presence of any bladder tumor during the follow-up. The secondary endpoint was to perform a cost–benefit analysis of this alternative approach. Resource consumption analysis was based on the impact on the direct use of resources per patient. No overhead or indirect costs were considered, while costs related to the operation, length of stay, outpatient consumables, and nursing care were included. The average time of use for the operating room, average hospital stays, and diagnostic tests, including specialist visits before and after admission, were estimated from 150 TURs performed in the reference center from December 2019 to May 2020.Categorical variables were reported as frequencies and proportions; continuous variables were reported as medians and interquartile ranges (IQRs). For distribution analysis of categorical variables, chi-square test or Pearson’s exact test was used, as pertinent. Mann–Whitney test was used to compare the median of continuous variables with nonparametric distribution.Kaplan–Meier method was used to estimate recurrence-free survival (RFS). All statistical analyses were performed with the Stata/SE, version 17 .Among 87 patients with T1 NMIBC presenting between May 2020 and December 2021, 76 patients met the inclusion criteria, signed the informed consent, and were subsequently enrolled in the trial. Median age was 75.4 years (67.6–80.3) with the majority being men . Most of the patients presented with primary BC , while 8 patients (10.6%) had a recurrent BC with a previous diagnosis of G2/LG Ta BC in 4 patients and G1/LG Ta BC in the other 4 cases; none of the patients had a history of CIS. Median time to recurrence was 31 months (IQR 22.5–32.7), and 3 patients had previous chemotherapy instillations with mitomycin. Multifocal lesions and tumor greater than 3 cm in diameter were observed in 18 (23.7%) and 33 (43.5%) patients, respectively. Only 6 patients (7.9%) had a low-grade NMIBC. Patient characteristics are summarized in Only 1 upstaging to MIBC at standard ReTUR was observed, while two patients died during the follow-up from causes other than BC. Considering only the 57 patients who initially avoided the ReTUR, with a median follow-up of 11 months, disease recurrence was observed in 10/57; among them, 7 belonged to the group that avoided ReTUR and underwent directly a BCG induction course, while the other 3 initially avoided ReTUR but underwent salvage ReTUR because of positive UC or cystoscopy. Notably, 8 patients had an HG recurrence Table 2.The mean cost of ReTUR was estimated at 1,854 € per patient, while the mean cost of conservative approach (UC and outpatient cystoscopy) was estimated at 95 € per patient. Resource consumption and related cost analysis are shown in Our preliminary results show that ReTUR might be avoided in selected T1 BC patients, turning into an estimated savings of about 855.6 € per patient diagnosed with pT1 BC.Herein, we present the preliminary results of HuNIRe trial; the study was designed to evaluate the possibility of identifying those T1 NMIBC patients who could avoid a second resection and directly begin the BCG induction course.To the best of our knowledge, this is the first study investigating an alternative approach to standard ReTUR in this subset of patients. According to our preliminary results, ReTUR may be spared in a substantial proportion of appropriately selected patients, and this approach may be effective both from an oncological and from a resource–consumption perspective. More specifically, we avoided 66% of ReTUR in patients with a complete primary resection and, even more importantly, no case of MIBC was missed.The rationale for avoiding a ReTUR is based on the fact that this approach may be considered an overtreatment in selected individuals and could also lead to a significant delay of adjuvant therapies. The influence of the time between surgical treatment and BCG induction cycle on oncological results is still a matter of debate. However, EAU guidelines recommend the onset of BCG immunotherapy at least 2 weeks after TUR and no time limit is set . PerformA recent randomized trial showed that patients subjected to a second TUR had significantly higher recurrence-free, progression-free, and overall survival . HoweverAlthough there has been a softening of the European guideline position regarding ReTUR, which is no longer indicated for HG Ta NMIBC patients, there is still an open debate about its clinical usefulness in every patient with a T1 BC .en bloc technique were independent predictors of the absence of tumor at ReTUR, suggesting the possibility of avoiding ReTUR in selected patients , ranging from 34% to 95%, and negative predictive value (NPV), ranging from 46% to 86% in HG BC. However, specificity (SP) remains lower than 70% . ThroughOne of the strengths of our study is the analysis of the impact that avoiding a ReTUR in selected T1 NMIBC patients might have on hospital resource.However, the impact of an NMIBC diagnosis extends beyond quantifiable factors. Indirect costs, such as days of work lost by the patient and his/her caregivers, are difficult to estimate and would deserve a detailed analysis . Indeed,Lastly, Ferro et al.  reportedOur study is not devoid of limitations mainly due to the lack of a control group. We also acknowledge that the small sample size could have limited the strength and reproducibility of our results. Additionally, the median follow-up was limited to 11 months, therefore being too short to provide an accurate estimate of oncological outcomes. Indeed, a comparison of long-term oncological outcomes between patients enrolled in the current protocol and those subjected to the standard of care is warranted.In the current prospective study, we demonstrated that avoiding ReTUR in appropriately selected patients with T1 NMIBC is feasible and safe. This approach may limit the psychological impact and potential morbidities of a second surgery while providing significant resource savings.However, the findings are preliminary and internally validated; furthermore, the study design does not permit to conclude on the oncological safety of this approach. Therefore, in order to confirm our preliminary results, randomized controlled trials are mandatory.Furthermore, extended follow-up and a larger sample size, as well as further studies on novel diagnostic tools, are needed to obtain a better patient selection and a safer therapeutic strategy balancing risks, oncological outcomes, and resource consumption.The original contributions presented in the study are included in the article/The studies involving human participants were reviewed and approved by Comitato etico IRCCS Humanitas Research Hospital. The patients/participants provided their written informed consent to participate in this study.Paolo Casale, IRCCS Humanitas Research Hospital Rozzano, Milan, Italy; Alberto Saita, IRCCS Humanitas Research Hospital Rozzano, Milan, Italy; Andrea Gobbo, Department of Biomedical Sciences, Humanitas University Pieve Emanuele, Milan, Italy; Edoardo Beatrici, Department of Biomedical Sciences,Humanitas University Pieve Emanuele, Milan, Italy; Pier Paolo Avolio, Department of Biomedical Sciences, Humanitas University Pieve Emanuele, Milan, Italy; Alessandro Uleri, Department of Biomedical Sciences, Humanitas University Pieve Emanuele, Milan, Italy; Marco Paciotti, Department of Biomedical Sciences, Humanitas University Pieve Emanuele, Milan, Italy; Vittorio Fasulo, Department of Biomedical Sciences, Humanitas University Pieve Emanuele, Milan, Italy; Nicola Frego, Department of Biomedical Sciences, Humanitas University Pieve Emanuele, Milan, Italy; Davide Maffei, Department of Biomedical Sciences, Humanitas University Pieve Emanuele, Milan, Italy; Pietro Diana, Department of Biomedical Sciences, Humanitas University Pieve Emanuele, Milan, Italy; Matteo Zanoni, Urology Unit, Humanitas Mater Domini, Castellanza, Varese, Italy; Luigi Domanico, Department of Urology, Humanitas Gavazzeni, Bergamo,Italy; Devis Collura, SC Urology and Reconstructive Andrology PO Humanitas Gradenigo, Turin, Italy; Maria Grazia Elefante, Department of Pathology, IRCCS Humanitas Research Hospital, Rozzano, Milan, Italy; Miriam Cieri, Department of Pathology, IRCCS Humanitas Research Hospital, Rozzano, Milan, Italy.RC, RH, and GG contributed to conception and design of the study. RC organized the database. RC and GL performed the statistical analysis. RC, RH, ML, and GL wrote the article. All authors contributed to article revision and read and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


As the importance of measuring electron density has become more significant in the material fabrication industry, various related plasma monitoring tools have been introduced. In this paper, the development of a microwave probe, called the measurement of lateral electron density (MOLE) probe, is reported. The basic properties of the MOLE probe are analyzed via three-dimensional electromagnetic wave simulation, with simulation results showing that the probe estimates electron density by measuring the surface wave resonance frequency from the reflection microwave frequency spectrum (S Plasma applications in modern technologies cover numerous fields such as material fabrication, nuclear fusion, medical treatment, agriculture, and catalysis ,2,3,4. ARecently, to improve throughput and productivity, process monitoring technology has become significant because the price of a patterned wafer has steadily grown and loss by unstable process is no longer negligible ,7,8,9. PElectron density is a significant factor among these monitoring parameters since it is believed to be directly related to processing time and quality ,11,17,18Based on the plasma cutoff phenomenon, which was firstly employed in a microwave interferometry measuring phase shift due to the plasma cutoff for measuring the line-integrated electron density ,28, You spectrum ,11,18,25spectrum , and furspectrum ,18. Sugaspectrum ,29,30,31spectrum . With sispectrum ,33,34. Itrum [11 ,36,37,38trum [11 ,38. AmonA small and simple probe size is desirable for the following reasons. First, a small probe design lowers plasma perturbations as well as thermal damage on the probe antenna from the plasma. Recently, high ion fluxes and energy have been generated with high average power (10–30 kW), so thermal damage issues should be considered ,40. SecoTo realize such advantages, this paper proposes the measurement of lateral electron density (MOLE) probe. As the probe can be made by merely cutting an RG-401 coaxial cable, it represents the smallest and simplest design among planar microwave probes. For the principle, the MOLE probe is based on the surface wave resonance (SWR) at the plasma–sheath interface and measures the SWR frequency in Sbe (PAP)  and the be (PAP) . The difo in S11 . This faThe remainder of this paper is as follows. In the second section, the simulation method to verify the operation physics of the proposed probe is discussed. In the third section, an experimental demonstration of the MOLE probe is described and analyzed. Finally, in the conclusion section, a summary of this paper is provided.To analyze the basic properties of the MOLE probe, the high-frequency time-domain solver provided by CST Microwave Suite was utilized. It solves Maxwell’s equations in three-dimensional (3D) space via the finite-difference time-domain method for the typical microwave range, from several MHz to several tens of GHz. This simulation approach has been widely used to analyze and optimize microwave probes such as the planar cutoff probe, planar curling probe, and planar multipole resonance probe; related simulation details can be found in ,23,31,35f). Here, model in . Brieflyns as in , and theThe benchmark dimension of the coaxial cable is a RG-401 cable used in this experiment; not exactly the same but similar dimensions for simple numeral. The coaxial cable consists of a cylindrical copper core 2.0 mm in diameter, a polytetrafluoroethylene (PTFE) tube 6.7 mm in outer diameter and 2.0 mm in inner diameter, a relative dielectric constant of 2.1, and an aluminum tube 8.0 mm in outer diameter and 6.7 mm in inner diameter.f)/f)).A nanosecond Gaussian pulse  to an in-house one-turn antenna through an rf matcher . A ceramic plate was used to both sustain the vacuum and propagate rf power into the gas inside the chamber. Argon gas (99.999% purity) was injected through a mass flow controller . A rotary pump  was used to generate a vacuum in the chamber via pumping port, with a resultant base pressure of 0.6 mTorr.The MOLE probe was inserted into the chamber via a NW-40 port with distance of 140 mm from the ceramic plate. One end of the probe was located in the center of the chamber a and theTo demonstrate the operation of the MOLE probe, a cutoff probe was inserted into the chamber via a NW-40 port opposite from the MOLE probe. The cutoff probe was connected to vector network analyzer 2  via two SMA cables. The cutoff probe can precisely measure the electron density by measuring the cutoff frequency in Slsewhere ,47,48,49rf power ,48,49. TFinally, to demonstrate the operation of the MOLE probe in non-invasively measuring lateral electron density, the probe was positioned on the chamber wall as shown in The MOLE probe however measures the electron density several times lower for the bulk and 10 times lower for the wall mount than the cutoff probe. This is because of thin sheath condition and the plasma non-uniformity ,50. Base (5×λDe) , where λa few eV  where thThe development of a microwave probe called the measurement of lateral electron density (MOLE) probe was described in this work with simulation study and experimental demonstration. Lateral as used here refers to the plasma–sheath edge near the chamber wall. Results of a 3D E/M wave simulation analysis established that the MOLE probe can measure the SWR frequency (


The distribution of Muribaculaceae between normal mice versus microgravity mice was significantly different, at 62% and 36.4%, respectively (p < 0.05). Furthermore, a significant decrease in 11 bacteria was observed in mice under simulated microgravity, including Akkermansia muciniphila, Eubacterium coprostanoligenes, Bacteroides acidifaciens, Clostridium leptum, Methylorubrum extorquens, Comamonas testosterone, Desulfovibrio fairfieldensis, Bacteroides coprocola, Aerococcus urinaeequi, Helicobacter hepaticus, and Burkholderiales. Further studies are needed to elucidate gut bacterial metabolites of these identified bacterial species in microgravity conditions and normal environment. Notably, the influence of these metabolites on obesity, neuroprotection, musculoskeletal and cardiovascular dysfunction, longevity, inflammation, health, and disease in astronauts ought to be investigated and will be important in developing procedures against adverse effects in astronauts following space travel.We utilised a ground-based microgravity hindlimb unloading (HU) mouse model to elucidate the gut microbiota bacterial changes in mice under a simulated microgravity environment. Four-month-old, male C57/Bl6 mice were randomly divided into ground-based controls and the HU groups and kept under controlled environmental conditions. For the microgravity environment, the mice were suspended in special cages individually for 20 days. At the end of the suspension, the mice were sacrificed; gut dissections were performed, followed by a metagenomic analysis of bacterial species, which was carried out by extracting DNA and 16S rRNA analysis. The results revealed that the gut bacterial communities of mice under gravity and microgravity were different. Notably, our findings revealed differences in the bacterial community structure. Around 449 bacterial OTUs were specific to mice kept under normal gravity versus 443 bacterial OTUs under microgravity conditions. In contrast, 694 bacterial OTUs were common to both groups. When the relative abundance of taxa was analyzed, Bacteroidetes dominated the gut (64.7%) of normal mice. Conversely, mice in the microgravity environment were dominated by Firmicutes (42.7%), and the relative abundance of Bacteroidetes differed significantly between the two groups ( Astronauts have been traveling to space since 1961, and factors such as microgravity and radiation exposure are known to cause physiological changes ,3. PreviFaecalibacterium, a beneficial butyrate producer. Conversely, species associated with chronic inflammation of the intestine, namely Parasutterella were observed. Furthermore, a decrease in Akkermansia, that is associated with anti-inflammatory properties, were seen. Therefore, prebiotics containing Akkermansia, to diminish diseases concomitant with inflammatory responses, have been suggested [A substantial study designated “the Astronaut Microbiome Project” is being accomplished to elucidate the astronaut microbiome with the aim to determine microbiome changes during space travel . This stuggested ,9.Herein, we utilised a hindlimb unloading (HU) mouse model, which has been well ascertained as a ground-based microgravity model. The model involves suspending the mouse from its tail in a cage, so that the hindlimbs are elevated from the ground with a 30-degree head-down tilt. Due to mechanical unloading of the hindlimbs and cephalic fluid shifts, the mouse partly recapitulates the simulated microgravity conditions similar to astronauts in space. Several physiological changes are reported in these mice, including blood redistribution, cephalic fluid shift, and insufficient oxygen and blood supply to the gastrointestinal tract ,11. We cProtocols for animals were sanctioned and approved by University ACUC  in agreement with accepted international standards.For the HU model, 4-month-old male c57BL/6j mice were utilized. This age is considered a mature adult age for mice, which is equivalent to approximately 30-year-old humans . This agAfter euthanasia, the stomach and small and large intestines of control and HU mice were dissected immediately, frozen in liquid nitrogen, and deposited at −80 °C for further molecular studies.g for 10 min, the supernatant was first extracted with phenol/chloroform/isoamyl alcohol at a ratio of 25:24:1 (v/v/v) and then with chloroform/isoamyl alcohol at a ratio of 24:1 (v/v). Next, DNA was pelleted using potassium acetate  and 95% ethanol, followed by centrifugation at 15,000× g for 10 min. The pellet was washed twice with 70% ethanol and then dissolved in 0.4 mL of buffer . Next, samples were incubated with 10 mg of RNase for 30 min at 37 °C to remove residual RNA. This was followed by extraction with chloroform/isoamyl alcohol to remove protein. Finally, the upper layer was collected in a tube containing 2.5 vol of ethanol (second precipitation) to precipitate the DNA and centrifuged for 10 min at 15,000× g. The DNA pellet was washed twice, dried, and then re-suspended in 0.2 mL dH2O. DNA purity and concentration were elucidated using 1% agarose gels [The metagenomic studies were performed by extracting DNA from the mice gut as described before . Brieflyose gels ,19. Acco® High-Fidelity PCR Master Mix , 0.2 μM of each primer and 10 ng target DNA, and cycling conditions consisted of a first denaturation step at 98 °C for 1 min, followed by 30 cycles at 98 °C (10 s), 50 °C (30 s) and 72 °C (30 s), and a final 5 min extension at 72 °C. An equal volume of 1X loading buffer (containing SYB green) was mixed with PCR products and electrophoresed on 2% agarose gel [The 16S rRNA/18S rRNA/ITS genes in distinct regions (V3-V4/16S) were amplified with specific primers . All PCR mixtures contained 15 μL of Phusionrose gel . The PCRrose gel  for subshttp://ccb.jhu.edu/software/FLASH/, accessed on 1 March 2022), a very fast and accurate analysis tool designed to merge paired-end reads when at least some of the reads overlap with the reads generated from the opposite end of the same DNA fragment, and the splicing sequences were called Raw Tags. Quality filtering on the raw tags was performed using the fastp (Version 0.20.0) software to obtain high-quality Clean Tags. The Clean Tags were compared with the reference database  using Vsearch (Version 2.15.0) to detect the chimera sequences, and then the chimera sequences were removed to obtain the Effective Tags. For the Effective Tags obtained previously, denoise was performed with DADA2 or deblur module in the QIIME2 software (Version QIIME2-202006) to obtain sequence variants, and then variants with abundance less than 5 were filtered out. Species annotation was performed using QIIME2 software. For 16S/18S, the annotation database is Silva Database, while for ITS, it is Unite Database. In order to study the phylogenetic relationship and the differences of the dominant species among different samples (groups), multiple sequence alignment was performed using QIIME2 software. The absolute abundance of variants was normalized using a standard sequence number corresponding to the sample with the least sequences. Subsequent analysis of alpha diversity and beta diversity were all performed based on the output of normalized data. In order to analyze the diversity, richness and uniformity of the communities in the sample, alpha diversity was calculated from 7 indices in QIIME2. In order to evaluate the complexity of the community composition and compare the differences between samples (groups), beta diversity was calculated in QIIME2. To study the significance of the differences in community structure between groups, the adonis and anosim functions in the QIIME2 software were used to do analysis. To find out the significantly different species at each taxonomic level , the R software (Version 3.5.3) was used to do MetaStat and t-test analysis.As sequencing resulted in some “dirty data”, the raw data was merged and filtered to obtain clean data to make the information analysis accurate and reliable. Briefly, paired-end reads were assigned to samples based on their unique barcodes and were truncated by cutting off the barcodes and primer sequences. Paired-end reads were merged using FLASH . HU for 20 days resulted in a significant reduction in body weights . The HU mice also showed alterations in the weights of other body organs, including atrophy of hindlimb muscles, thus validating the mouse model. On the other hand, we did not observe any significant reduction in mice behavior, physical activity, or food and water intake.At the start of the experiment, there was no significant difference in the body weights of control and HU mice . Next, OTU classification was accomplished on all high-quality sequences with 97% similarity, utilising the Uparse software, and sequences with the largest abundance within OTUs were selected as representative sequences to be analysed in the Silva-16S database. The data depicted a total of 3898 OTUs, that is, 2015 and 1883 OTU for Group A and Group B, respectively.The gut bacterial communities of gravity and microgravity were different, as shown in p < 0.05) , and these were designated to show distribution histograms of relative abundance of taxa to visualize taxa with higher relative abundance and proportion in different classification levels of each sample. The relative abundance of taxa in the phylum and genus is shown in  < 0.05) D. Likewi < 0.05) . Overallpostipes B.A boxplot was generated to show the difference of Beta Diversity indices between groups. The data indicate that both groups were different in bacterial community structure .Akkermansia muciniphila, Eubacterium coprostanoligenes, Bacteroides acidifaciens, Clostridium leptum, Methylorubrum extorquens, Comamonas testosterone, Desulfovibrio fairfieldensis, Bacteroides coprocola, Aerococcus urinaeequi, Helicobacter hepaticus, and order Burkholderiales  and encodes more than 3 million genes that produce thousands of metabolites, with many functions that impact the overall health of the host ,23. VariIn the present study, we employed the hindlimb suspension mouse model, a ground-based in vivo microgravity model that mimics physiological changes concomitant with space travel ,29. A liAkkermansiamuciniphila in mice in a simulated microgravity environment in comparison to normal mice, which is interesting as this genus is typically correlated with anti-inflammatory properties [Akkermansia, and, therefore, pre-biotics comprising Akkermansia to reduce the chance of diseases associated with chronic inflammatory responses has been proposed [Of note, the data from our study depicted reduced levels of operties . This daproposed ,9.Eubacterium coprostanoligenes in mice under simulated microgravity in comparison to normal mice. It is recognised that members of the genus Eubacterium spp. produce butyrate and may play a pivotal role in the suppression of inflammation and immunomodulation of the gut [Eubacterium spp. also participates in bile acid and cholesterol transformations and contributes to gut homeostasis. Gut dysbiosis and modifications in Eubacterium spp. within the gut have been associated with disease states [Eubacterium spp. has been depicted to carry out metabolic alterations in the gut with beneficial effects on human health, such as the detoxification of toxic compounds into non-toxic states [Oxalibacterium formigenes, a betaproteobacterium within the order Burkholderiales, is one of the few bacteria in the colon with well described health benefits and regulates the homeostasis of oxalic acid while also preventing kidney stone formation [Our data also depicted a decrease in  the gut . Eubactee states . Furtherc states . Our datormation .Firmicutes and Bacteroidetes are the two most important bacterial phyla that inhabit the gut and play a pivotal role in maintaining homeostasis in the host . A balanAkkermansia, should also be tested in vivo in mice as pre/probiotics. Future studies are needed to elucidate metabolites produced by gut bacteria in microgravity conditions in contrast to normal environments. Notably, the influence of these molecules on obesity, neuroprotection, longevity, inflammation, health, and disease in astronauts needs to be clarified. These studies will be important in developing appropriate procedures against the adverse modifications observed in astronauts following space travel.In conclusion, the data from our study depicted the translational value of the in vivo hindlimb suspension microgravity mouse model, and the gut microbiome composition in normal conditions as well as simulated microgravity conditions were determined. This is important as in vivo studies can help identify changes in microbial diversity and composition and to subsequently test pre- and/or post-biotics. Based on our findings, several bacterial species were identified that depicted a significant decrease in microgravity conditions compared to normal mice and alterations in the ratio of Bacteroidetes to Firmicutes was observed under simulated microgravity conditions. Bacterial species that were significantly decreased should be isolated in future studies, and condition media containing their metabolites should be prepared and investigated in order to prepare pre/probiotics. These should then be tested using this model in microgravity and normal conditions. Furthermore, given the logistical issues of testing directly in astronauts, species already identified in the “astronaut microbiome project”: such as