Tetrodes, consisting of four twisted micro-wires can simultaneously record the number of neurons in the brain. To improve the quality of neuronal activity detection, the tetrode tips should be modified to increase the surface area and lower the impedance properties. In this study, tetrode tips were modified by the electrodeposition of Au nanoparticles (AuNPs) and dextran (Dex) doped poly (3,4-ethylenedioxythiophene) (PEDOT). The electrochemical properties were measured using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). A decrease in the impedance value from 4.3 MΩ to 13 kΩ at 1 kHz was achieved by the modified tetrodes. The cathodic charge storage capacity (CSC(C)) of AuNPs-PEDOT deposited tetrodes was 4.5 mC/cm², as determined by CV measurements. The tetrodes that were electroplated with AuNPs and PEDOT exhibited an increased surface area, which reduced the tetrode impedance. In vivo recording in the ventral posterior medial (VPM) nucleus of the thalamus was performed to investigate the single-unit activity in normal rats. To evaluate the recording performance of modified tetrodes, spontaneous spike signals were recorded. The values of the L-ratio, isolation distance and signal-to-noise (SNR) confirmed that electroplating the tetrode surface with AuNPs and PEDOT improved the recording performance, and these parameters could be used to effectively quantify the spikes of each cluster.
Animals ; Brain ; Dextrans ; Dielectric Spectroscopy ; Electric Impedance ; Electrodes ; Electroplating ; Microelectrodes ; Nanoparticles* ; Neurons ; Rats ; Thalamus

Objectives: Tuberculosis (TB) and drug-resistant TB (DR-TB) are national health burdens in Vietnam. In this study, we investigated the prevalence of rifampicin (RIF) and/or isoniazid (isonicotinic acid hydrazide, INH) resistance in patients with suspected TB, and applied appropriate techniques to help rapidly target DR-TB. Methods: In total, 1,547 clinical specimens were collected and cultured using the BACTEC MGIT system (Becton Dickinson and Co.). A resazurin microtiter assay (REMA) was used to determine the proportions of RIF and/or INH resistance. A real-time polymerase chain reaction panel with TaqMan probes was employed to identify the mutations of rpoB and katG associated with DR-TB in clinical isolates. Genotyping of the identified mutations was also performed. Results: A total of 468 Mycobacterium tuberculosis isolates were identified using the REMA. Of these isolates, 106 (22.6%) were found to be resistant to 1 or both antibiotics. Of the resistant isolates, 74 isolates (69.8%) were resistant to isoniazid (INH) only, while 1 isolate (0.94%) was resistant to RIF only. Notably, 31 isolates (29.24%) were resistant to both antibiotics. Of the 41 phenotypically INH-resistant isolates, 19 (46.3%) had the Ser315Thr mutation. There were 8 different rpoB mutations in 22 (68.8%) of the RIF-resistant isolates. The most frequently detected mutations were at codons 531 (37.5%), 526 (18.8%), and 516 (6.3%). Conclusion To help prevent new cases of DR-TB in Vietnam, it is crucial to gain a comprehensive understanding of the genotypic DR-TB isolates.

Backgroud: The aim of this study is to update on antibiotic resistance of common pathogenical bacteria isolated in Hue University of Medicine and Pharmacy Hospital (Hue UMP Hospital). Methodology: Use of the agar disk diffusion method to test the susceptibility to antimicrobial agents of 3709 bacterial strains from infected patients hospitalized in Hue UMP Hospital in 2020 - 2022. Results: Among 3709 strains of pathogenical bacteria isolated, S.aureus was found with the rate of 29.9%, followed by E. coli (24.5%), Pseudomonas aeruginasa (17.8%), Enterococcus spp. (11.8%), Klebsiella spp (9.7%) and Acinetobacter spp (4.1%). The proportion of bacterial isolates has changed, but Staphylococcus aureus is still highest rate. S.aureus is resistant to many antibiotics, but MRSA strains have decreased significantly, from 73.3% in 2020 to 62.5% in 2022. Pseudomonas aeruginosa was resistant to some of the group A recommended antibiotics such as ceftazidime, piperacillin-tazobactam with the rate of 56.6% and 48.7%. The percentage of E. coli with ESBL strains (+) was at 28.2% - 30.3%. Enterococus spp strains are still sensitive to vancomycin (83.1% - 91.9%). The rate of Klebsiella ESBL (+) is only 6.9% to 8.2%. The strains of Acinetobacter spp were highly resistant to Piperacillin (100%) and Ceftriaxone (96.5%) but they are still sensitive to imipenems 70 - 71%, highly sensitive to Doxycillin (95.2%) and Cefotaxime (88.4%). Conclusion: Many bacterial strains are resistant to many commonly antibiotics. Providing timely, regular, and effective management of antibiotic resistance patterns for common pathogenic bacteria in hospitals, will help reduce the risk of bacterial resistance.