Objective To investigate the effects of extracellular signal regulated kinase ( ERK)signaling pathway on cell cycle of airway smooth muscle cells( ASMCs) in asthmatic rats. Methods Thirty Wistar rats were randomly assigned to a control group and an asthma group( 15 rats in each group) . Asthma model was established by ovalbumim sensitization and challenge. ASMC were isolated and cultured in vitro. The ASMCs from the asthmatic rats were treated with ERK activator epidermal growth factor ( EGF)and inhibitor PD98059, respectively. The expressions of cyclin D1 and CDK2 in ASMCs were detected by immunocytochemical staining. The expressions of ERK1 /2 and p-ERK1 /2 protein were observed by western blotting for measurement of ERK activation rate. Results Compared with the control group[ 54. 17 ±6. 11,61. 04 ±4. 09, ( 49. 91 ±3. 26) % , respectively] , the expressions of cyclin D1 protein and CDK2 protein,and the rate of ERK activation of ASMCs from the asthmatic rats significantly increased[ 76. 15 ±4. 88,92. 30 ±7. 95, ( 82. 37 ±5. 78) % , respectively] ( P lt; 0. 05) . Furthermore, compared with those before treatment, the expression of cyclin D1 and CDK2, and the rate of ERK activation of ASMCs significantly decreased after treatment with PD98059 [ 58. 78 ±4. 60, 69. 15 ±5. 83, ( 54. 01 ±4. 12) % , respectively]( P lt; 0. 05) , and significantly increased after treatment with EGF[ 119. 28 ±8. 14, 134. 77 ±9. 26, ( 91. 57 ±5. 32) %, respectively] ( P lt;0. 05) . Conclusion ERK1/ 2 participates in proliferation regulation of ASMCs in asthma by enhancing the expressions of cyclin D1 and CDK2, which promotes quiescent cells into S phase.
Objective To analyze the clinical features of rickettsial infection complicated with pulmonary embolism and to improve clinicians’ knowledge of rickettsial infection complicated by thromboembolism events. Methods We retrospectively analyzed the clinical data of a patient with pulmonary thromboembolism complicated by Rickettsial felis infection and conducted a review of the relevant literature. The search terms "Rickettsia/Scrub typhus, thrombosis" or "Rickettsia/ Scrub typhus, embolism" were used to search the Wanfang ,VIP ,Chinese National Knowledge Infrastructure and PubMed databases from January 1985 to May 2023, respectively. Results The 81-year-old male patient was admitted to the hospital on June 1, 2021 due to "dizziness, sore throat for 11 days, fever for 7 days, and shortness of breath for 3 days". Physical examination revealed a eschar-like rash behind the left ear, venous thrombosis in both lower limbs was detected by color ultrasound, computed tomographic pulmonary angiography indicated multiple pulmonary embolism in both lungs, and positive rickettsiae on peripheral blood next-generation sequencing, confirming the diagnosis of Rickettsial felis infection complicated by venous thromboembolism (VTE) in both lower limbs and pulmonary embolism. Twenty manuscripts, including 20 cases, were retrieved from databases. Among them, Rickettsial felis infection combined with thromboembolism event was not found. With the addition of our case, a total of 21 cases were analyzed in detail. Six of the 21 cases were complicated with VTE, 10 with pulmonary embolism, 5 with intracranial venous thrombosis, 6 with thrombosis at other sites (jugular venous thrombosis, mesenteric thrombosis, aortic thrombosis, etc), and 8 of which had concurrently involved systemic thrombosis. Of the 4 deaths, 2 cases had mesenteric embolism, 1 case had cerebral infarction, and 1 case had systemic multiple thrombus. Conclusions Rickettsial infection symptoms and signs are often atypical, can be complicated with lower limb VTE or pulmonary embolism. Early identification, diagnosis and treatment are very important, especially for patients with dyspnea, chest pain and other related symptoms.