[Application of tracheotomy in the treatment of severe cases of COVID-19]

Objective: To discuss the the effects, indications and protective measures of tracheotomy for severe cases of coronavirus disease 2019 (COVID-19) patients. Methods: A retrospectively analysis was conducted to explore the clinical data of COVID-19 patients who received tracheotomy in February to March 2020, and descriptive statistics were used to analyze the indication of tracheotomy, particularity of intraoperative treatment and protective measures. Results: A total of 4 cases were included in this article. All patients were successfully operated. One case had postoperative incision continuous bleeding, there were not other complications and nosocomial infection among the medical staff. The patient's condition was relieved in different degrees after the operation, who remained hospitalized. Conclusion: Tracheotomy for severe cases of COVID-19 can achieve certain curative effect, but the occurrence of tracheotomy related complications and nosocomial infection should be effectively controlled, and the risk benefit ratio of tracheotomy should be carefully weighed before surgery.

[Application of tracheotomy in the treatment of severe cases of COVID-19]

Objective: Todiscuss the the effects, indications and protective measures of tracheotomy for severe cases of 2019 novel corona virus disease(COVID-19)patients. Methods: A retrospectively analyze was conducted to explore the clinical data of ofCOVID-19 patients who received tracheotomy in February to March 2020,descriptive statistics were used to analyze the indication of tracheotomy, particularity of intraoperative treatment and protective measures. Results: A total of 4 cases were included in this article, 3 cases were successfully operated, 1 case of postoperative incision continuous bleeding, there were not other complications and nosocomial infection among the medical staff.the patient's condition was relieved in different degrees after the operation, who remain hospitalized. Conclusion: Tracheotomy for severe cases of COVID-19 can achieve certain curative effect, but the occurrence of tracheotomy related complicationsand nosocomial infection should be effectively controlled, and the risk benefit ratio of tracheotomy should be carefully weighed before surgery.

[Advances of studies on the occurrence of the upper respiratory disease correlative with immunity and tobacco]

SummaryTobacco smoke exposure has obvious and complex effects on the immune system of the human upper respiratory tract, including pro-inflammatory and anti-immune effects. Exposure to tobacco smoke is closely related to the occurrence and development of allergic rhinitis, the common rhinitis and sinusitis. The innate immune system is influenced by tobacco smoking through its effects on the respiratory mucosa and its adjuncts, natural killer cells, dendritic cells, neutrophils and innate immune receptors. Cigarette smoke can also affect the humoral immunity and cellular immunity, altering the acquired immune condition of the upper respiratory tract. Tobacco smoke exposure promotes the occurrence and development of the upper respiratory tract infectious diseases and allergic diseases by changing the composition of microflora in the upper respiratory tract.

[Efficacy analysis of T type tube dilatation in adult cervical tracheal stenosis]

Objective:To investigate the efficacy, recurrence and strategy of T silicone tube dilatation for cicatricial stenosis of cervical trachea in adults.Method:Cinical data of 37 cases with the cervical tracheal stenosis were retrospectively analyzed, who were firstly treated by T shape silicone tube dilation for at least 10 months, from Jun 2006 to Jun 2016.Result:In 37 adult patients with cicatricial stenosis of the trachea, 29 cases were caused by tracheal intubation or incision, 6 cases were traumatic, and 2 cases were multiple osteochondritis. Twentythree cases were experienced one time surgery and extubated successfully, 8 cases were experienced 2 times and more than 2 times surgery (sternohyoid muscle flap pedicled hyoid bone with T tube expansion in 3 cases, tracheal endoscopic dilatation in 2 cases, T tube dilatation in 3 cases), extubation success rate of 83.7%. Among the 6 cases with failure of extubation, 2 cases were multiple osteochondritis, 3 cases had severe scar constitution, 1 cases were lost of follow-up.Conclusion:T type silicon tube expansion for the treatment of adult cervical tracheal stenosis can be achieved relatively high decannulation rate. For recurrent stenosis, we can consider to use various methods of expansion, and improve the decannulation rate. Intratracheal granulation tissuextubation after exbation should be observed for at least 1 month. For concurrent with polychondritis and severe scar the constitution, the operation should be carefully chosen.

A silent mutation in the ftsH gene of Escherichia coli that affects FtsH protein production and colicin tolerance

Among Escherichia coli tolZ mutants tolerant to colicins E2, E3, and D, one, KHI10, had a high frequency of lambda lysogenization, like the tolZ21 mutant, but unlike tolZ21 KHI10 grew on nonfermentable carbon sources. The tolZ10 gene of KHI10 was cloned and sequenced, and found to have a silent mutation in the ftsH gene, causing an alteration of a minor codon, CUA, for Leu-5 to a suboptimal codon, CUC. In spite of the change in a minor codon, the amount of the FtsH protein present in mutant cells was much less than that in the parental strain. In vivo transcription of the tolZ10 gene was not decreased relative to the wild-type ftsH gene. Analysis of other silent mutations altering the Leu-5 codon (CUA) to CUG or CUU (optimal and suboptimal codons, respectively) revealed that the decrease in concentration of FtsH was seen only with the CUC (tolZ10) codon. Prediction of the mRNA secondary structure suggested that the change from A to C extends the base pairing region longer by one base pair at the root of the stem structure, thus sequestering the Shine-Dalgarno sequence and decreasing the rate of the translational initiation of FtsH.

The tolZ gene of Escherichia coli is identified as the ftsH gene

Escherichia coli tolZ mutants are tolerant to colicins E2, E3, D, Ia, and Ib (Tol-), can grow on glucose but not on succinate or other nonfermentable carbon sources (Nfc-), and show temperature-sensitive growth (Ts). A 1.8-kb DNA fragment that complemented the tolZ mutation was cloned. The DNA fragment was sequenced, and one open reading frame was found. This frame was identical to a part of the E. coli FtsH protein, an ATP-dependent metalloprotease that binds to the cytoplasmic membrane. The tolZ gene was located at 69 min on the E. coli genetic map, and the mutation was complemented by a plasmid carrying the ftsH gene, indicating that the tolZ gene is identical to the ftsH gene. The mutated tolZ21 gene was also cloned and sequenced and was found to have a single base change that caused an amino acid alteration of His-418 to Tyr in the FtsH protein. The tolZ21 mutant showed Hfl- (high frequency of lysogenization) and Std- (stop transfer-defective) pheno-types, both of which are due to a mutation in the ftsH (hflB) gene. However, the ftsH1, ftsH101, and hflB29 mutants did not show Tol- and Nfc phenotypes. The tolZ21 mutant was found to have a suppressor mutation, named sfhC, which allowed cells to survive. The sfhC mutation alone caused no Tol-, Nfc-, Ts, or Hfl- phenotypes in the tolZ21 mutant.