Pre-treatment drug resistance of newly reported HIV-1 infected individuals in Wenzhou / 预防医学

Objective@#To know the pre-treatment drug resistance ( PDR ) status of newly reported human immunodeficiency virus type 1 ( HIV-1 ) infected individuals in Wenzhou, so as to provide guidance for antiretroviral therapy ( ART ). @*Methods@# Totally 232 plasma samples of newly reported HIV-1 infected individuals who had not received ART were collected in Wenzhou in 2019. Virus ( HIV-1 ) RNA was extracted, followed by reverse transcription PCR and nested PCR to amplify the pol region and sequence. Resistance mutations and resistance to non-nucleoside reverse transcriptase inhibitors ( NNRTIs ), nucleoside reverse transcriptase inhibitors ( NRTIs ) and protease inhibitors ( PIs ) was analyzed.@*Results@#The pol region sequences from 199 infected patients were obtained and the incidence of PDR was 8.04% ( 16/199 ). Eight genotypes were detected, including circulating recombinant forms ( CRFs ) CRF07_BC ( 47.24%, 94/199 ) and CRF01_AE ( 29.15%, 58/199 ) which were the dominant types. Two unique recombinant forms ( URFs ) were detected, namely URF( CRF01_AE/BC ) and URF( B/C ) . Thirty-one cases ( 15.58% 31/199 ) had drug-resistant mutations. For NNRTIs, NRTIs and PIs, 20 cases ( 64.52% ) , 2 cases ( 6.45% ) and 9 cases ( 29.03% ) with drug resistance mutations were detected, respectively. The resistance mutations to NNRTIs included K101E, K103N/R, V106I, E138K, V179D/E/T, Y181C, G190A and H221Y. Four cases each had two resistance mutations to NNRTIs. The resistance mutations to NRTIs were V75M and M184V. The resistance mutations to PIs were M46I, L33F and Q58E. For the newly released NNRTI drug Doravirine ( DOR ), two cases were found to have mutations of resistance. @*Conclusions@#The incidence of PDR among newly reported HIV-1 patients in Wenzhou is 8.04%, mainly caused by NNRTIs drug-resistant mutation. Resistance to the new drug DOR has emerged. The surveillance of drug resistance should continue to be strengthened.

Research on prediction method of medical equipment sudden fault / 中国医学装备

Objective:To do research on prediction method of medical equipment sudden fault for the requirement of medical security at sea which is away from base.Methods: Sudden fault data of the medical equipment is a random variable which often manifest as the time of sudden fault happening. The possible distribution type of fault data is hypothesized according to the engineering experience. In order to ensure the sudden fault density function of medical equipment, parameter estimation and distribution fit test are carried out for the fault data.Results: The sudden fault prediction model of medical equipment is established to get the future sudden fault probability of medical equipment based on the distribution function of fault data.Conclusion: The results of case analysis validate the rationality of sudden fault prediction model.

Increased L-arginine Production by Site-directed Mutagenesis of N-acetyl-L-glutamate Kinase and proB Gene Deletion in Corynebacterium crenatum / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>In Corynebacterium crenatum, the adjacent D311 and D312 of N-acetyl-L-glutamate kinase (NAGK), as a key rate-limiting enzyme of L-arginine biosynthesis under substrate regulatory control by arginine, were initially replaced with two arginine residues to investigate the L-arginine feedback inhibition for NAGK.</p><p><b>METHODS</b>NAGK enzyme expression was evaluated using a plasmid-based method. Homologous recombination was employed to eliminate the proB.</p><p><b>RESULTS</b>The IC50 and enzyme activity of NAGK M4, in which the D311R and D312R amino acid substitutions were combined with the previously reported E19R and H26E substitutions, were 3.7-fold and 14.6% higher, respectively, than those of the wild-type NAGK. NAGK M4 was successfully introduced into the C. crenatum MT genome without any genetic markers; the L-arginine yield of C. crenatum MT-M4 was 26.2% higher than that of C. crenatum MT. To further improve upon the L-arginine yield, we constructed the mutant C. crenatum MT-M4 proB. The optimum concentration of L-proline was also investigated in order to determine its contribution to L-arginine yield. After L-proline was added to the medium at 10 mmol/L, the L-arginine yield reached 16.5 g/L after 108 h of shake-flask fermentation, approximately 70.1% higher than the yield attained using C. crenatum MT.</p><p><b>CONCLUSION</b>Feedback inhibition of L-arginine on NAGK in C. crenatum is clearly alleviated by the M4 mutation of NAGK, and deletion of the proB in C. crenatum from MT to M4 results in a significant increase in arginine production.</p>