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CRISPR-Cas systems are the only RNA- guided adaptive immunity pathways that trigger the detection and destruction of invasive phages and plasmids in bacteria and archaea. Due to its prevalence and mystery, the Class 1 CRISPR-Cas system has lately been the subject of several studies. This review highlights the specificity of CRISPR-Cas system III-A in Mycobacterium tuberculosis, the tuberculosis-causing pathogen, for over twenty years. We discuss the difference between the several subtypes of Type III and their defence mechanisms. The anti-CRISPRs (Acrs) recently described, the critical role of Reverse transcriptase (RT) and housekeeping nuclease for type III CRISPR-Cas systems, and the use of this cutting-edge technology, its impact on the search for novel anti-tuberculosis drugs.
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Bacteriófagos , Mycobacterium tuberculosis , Sistemas CRISPR-Cas , Mycobacterium tuberculosis/genética , Bacteriófagos/genética , Plasmídeos/genética , Antituberculosos/metabolismoRESUMO
BackgroundTo clarify the characteristic and the duration of positive nucleic acid in children infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), including asymptomatic children. MethodsA total of 32 children confirmed with SARS-CoV-2 infection between January 24 and February 12, 2020 from four provinces in Western China were enrolled in this study and followed up until discharge and quarantine 14 days later. ResultsEleven children (34%) were asymptomatic, among whom six children had normal computed tomographic (CT) scan images. Age and gender were not associated with clinical symptoms or the results of CT scan in children infected with SARS-CoV-2. The concentrations of white blood cells and neutrophils were higher in children with asymptomatic infection than in children with clinical symptoms or CT abnormalities. Patients who presented with CT abnormalities had lower D-dimer or lower total bilirubin than those who had normal CT scan but clinical symptoms. All children recovered and no one died or was admitted to the pediatric intensive care unit (PICU). The mean duration of positive SARS-CoV-2 nucleic acid was 15.4 (SD=7.2) days and similar for both asymptomatic children and children with symptoms or CT abnormalities. We found a significant negative correlation between the lymphocyte count and the duration of positive nucleic acid test. ConclusionsChildren with asymptomatic infection should be quarantined for the same duration as symptomatic patients infected with SARS-CoV-2. The clinical significance and mechanism behind the negative correlation between the number of lymphocytes and the duration of positive SARS-CoV-2 needs further study.
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Decompensated liver cirrhosis has various life-threatening complications such as spontaneous bacterial peritonitis, hepatic encephalopathy, and sepsis, and the development of such complications is closely associated with bacterial translocation. Pathological bacterial translocation in patients with liver cirrhosis is caused by the impairment of intestinal barrier function, and thus bacteria can cross the intestinal barrier and enter the mesenteric lymph nodes or other sites. Therefore, a better understanding of the association between intestinal barrier and bacterial translocation in liver cirrhosis can provide new theoretical support for the treatment of liver cirrhosis. This article discusses the four major components of the intestinal barrier, namely the mechanical barrier, the immune barrier, the chemical barrier, and the biological barrier, as well as their changes during bacterial translocation.
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Objective To evaluate the effect of propofol on microcirculation in a rabbit model of hemorrhagic shock and resuscitation.Methods Twenty-four adult male rabbits,weighing 1.7-2.1 kg,aged 4-6 months,were equally randomized into sham operation (group S),hemorrhagic shock and resuscitation (group HS/R),or propofol (group P) groups.Hemorrhagic shock was induced by withdrawing blood from the left common carotid artery until mean arterial pressure was reduced to 40-50 mmHg which was maintained for 30 min.The animals were then resuscitated by infusion of shed blood and normal saline (2 times the volume of shed blood) in HS/R and P groups,and in addition propofol 20 mg · kg-1 · h-1 was infused intravenously in group P.Before blood-letting,immediately before resuscitation,and at 30 and 60 min after onset of resuscitation,arterial blood samples were collected for blood gas analysis,and pH value and lactic acid concentrations were recorded.Side-stream dark field imaging was employed to acquire the images of mesenteric microcirculation.Microcirculatory parameters like total vessel density,perfused vessel density,proportion of perfused vessels,and microvascular flow index were recorded.Results Compared with group S,pH value was significantly decreased,and lactic acid concentrations were increased immediately before resuscitation,and at 30 and 60 min after onset of resuscitation,and the total vessel density,perfused vessel density,proportion of perfused vessels,and microvascular flow index were decreased immediately before resuscitation in HS/R and P groups (P＜0.05).There was no significant difference in the parameters mentioned above between group HS/R and group P (P＞0.05).Conclusion Propofol exerts no effect on microcirculation in a rabbit model of hemorrhagic shock and resuscitation.
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Objective To investigate the effects of different depth of anesthesia on sublingual microcirculation. Meth?ods ASA gradeⅠ-Ⅱpatients (n=20) were scheduled for elective thyroid surgery and included in the prospective observa?tional study. Midazolam 0.05 mg·kg, sufentanil 0.3μg·kg-1 and rocuronium 0.6 mg·kg-1 were administrated intravenously to induce anesthesia which was then maintained by continuous intravenous infusion of propofol. Target medication concentra?tion increased 0.5 mg·L-1, regulated based on BIS. The patients underwent endotracheal intubation and mechanical ventila?tion. Sublingual microcirculations were evaluated by sidestream dark field (SDF) imaging at T1 (BIS baseline ), T2 (50 0.05). Conclusion When BIS value sit between 40 and 50, it can best inhibit stress response and attenuate the agitation of microcirculation.
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[Objective] To investigate the effect of naringin at different doses on the neuropathie pain produced by lumbar 5 spinal nerve ligafion (L5 SNL). [Methods] Using the method of behavioral test, we tested the 50% paw withdrawal threshold before and after intragastrieal application of naringin in the rats with L5 SNL. [Results] Naringin at 30, 90, 100 mg/kg but not at 10 mg/kg increased the 50% paw withdrawal threshold of 1.5 SNL rats significantly. Single application of Naringin (at 30 or 90 mg/kg) inhibited mechanical allodynia for around 6 hours, and the inhibitory effect persisted for 4 days after the cessation of the drug when naringin (30 mg/kg, daily) was consecutively applied for 7 days. [Conclusion] Intragastrical of naringin could relieve the neuropathic pain produced by peripheral nerve injury.
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Objective To prepare insulin-containing chitosan-thioglycollic acid conjugates microspheres and evaluate their hypoglycemic effect.Methods The insulin-containing chitosan-thioglycollic acid conjugates microspheres were prepared by the dry-in-oil method using the chitosan-thioglycollic acid conjugates which the content of thiol group was 983?mol?g-1.The hypoglycemic effect of the microsphere was evaluated by drug release test in vitro and hypoglycemic test on hyperglycemic rats.Results The insulin-containing chitosan-thioglycollic acid conjugates microspheres with an average diameter of 13?m were administered by intraduodenal and intraileal application,and gave visible decrease in plasma glucose level in 4h at a dose of 20IU?kg-1.The relative bioavailability of the latter compared to hypodermic injection was 29.9%.Couclusion The results showed that the bioavailability of oral insulin could be facilitated by insulin-containing chitosan-thioglycollic acid conjugates microspheres,and good biological availability was obtained when the microspheres were administered by intraileal application.
