Halophilic lactic acid bacteria - Play a vital role in the fermented food industry.

Halophilic lactic acid bacteria have been widely found in various high-salt fermented foods. The distribution of these species in salt-fermented foods contributes significantly to the development of the product's flavor. Besides, these bacteria also have the ability to biosynthesize bioactive components which potentially apply to different areas. In this review, insights into the metabolic properties, salt stress responses, and potential applications of these bacteria have been have been elucidated. The purpose of this review highlights the important role of halophilic lactic acid bacteria in improving the quality and safety of salt-fermented products and explores the potential application of these bacteria.

Chemical composition, anti-inflammatory and cytotoxic activity of essential oils from two Luvunga species (L. scandens and L. hongiaoensis) from Vietnam.

New essential oils (EOs) extracted from different parts of two Luvunga species (L. scandens and L. hongiaoensis) from Vietnam were investigated for their chemical composition, anti-inflammatory and cytotoxic activity. Sixty-nine total compounds were identified in the EOs by GC/MS. The major constituent of the leaf, fruit, and root EOs from L. scandens was ß-caryophyllene (71.5%, 63.0%, and 31.5% respectively). The main compounds in L. hongiaoensis EOs were ß-elemene (34.3% in leaf oil) and caryophyllene oxide (21.2% in root oil, 19.4% in stem oil). The EO from L. scandens fruits significantly inhibited nitric oxide production on LPS-induced RAW264.7 cells (IC50 = 37.95 ± 2.76 µg/mL). The EOs from L. hongiaoensis roots and L. scandens leaves and fruits exhibited cytotoxic activity against MCF-7, SK-LU-1, and HepG2 (IC50 from 49.74 ± 3.36 to 97.82 ± 8.61 µg/mL). This is the first report on L. hongiaoensis EOs and significantly complements the composition and bioactivity of L. scandens EOs.

Knowledge and Attitude Related to Hepatitis C among Medical Students in the Oral Direct Acting Antiviral Agents Era in Vietnam.

BACKGROUND: Medical students play important frontline roles in the prevention, early detection, and treatment of hepatitis C. This study investigated knowledge and attitudes toward hepatitis C among 5th- and 6th-year medical students and possible associated factors. METHODS: A cross-sectional survey was conducted among 2000 students from eight medical universities using a self-administered structured questionnaire. RESULTS: The mean knowledge and attitude scores for hepatitis C were 20.1 ± 4.0 (out of 26) and 10.6 ± 2.9 (out of 20), respectively. Approximately, three-quarters (74.4%) of the participants had a good knowledge score, but only a small proportion (3.1%) obtained a good attitude score. Although the participants had fairly high knowledge about the causes, consequences, and transmission routes of hepatitis C, there were important gaps in their knowledge about hepatitis C screening and treatment. In multivariate analysis, female students, 5th-year students, and students from the central provinces had significantly higher knowledge and attitude scores. There was a low positive correlation between knowledge and attitude scores. CONCLUSION: This study points out the need to update the medical training curriculum to improve the knowledge and attitude of students about hepatitis C infection.

Correlation Between the Amount of Extracellular Polymeric Substances and the Survival Rate to Freeze-Drying of Probiotics.

To demonstrate that the amount of extracellular polymeric substances (EPS) and the freeze-dried viability of probiotics are correlated. Three strains of probiotics including Lactiplantibacillus plantarum, Lactobacillus acidophilus, and Bifidobacterium bifidum were subjected to environmental challenges, such as temperature, pH, and carbon dioxide. The results indicated that the challenges could stimulate the EPS synthesis of the probiotics. The experimental correlation between the amount of synthesized EPS and the freeze-dried survival rate was also analyzed, and the viability of each of the three strains was represented by the following functions in which the equation of L. plantarum is y = - 0.0336x2 + 2.7059x - 14.849 with R2 = 0.9699, the B. bifidum's equation is y = - 0.0554x2 + 2.6243x - 13.654 with R2 = 0.9554, and the L. acidophilus's one was y = 0.0346x2 + 0.5862x - 9.1339 with R2 = 0.9733. This could be a new approach to determining the freeze-dried viability of probiotic strains based on the measured EPS content.

Subtotal Laryngectomy with Epiglottic Reconstruction for Glottic Carcinoma: A Single Institutional Experience.

Aim: Laryngeal cancer is a common form of head and neck cancer in Vietnam where the current treatment is surgery. Subtotal laryngectomy with epiglottic reconstruction, a conservative surgery, allows removal of anterior commissure including thyroid cartilage and paraglottic space and provides a maximum restoration of the anatomical structure of the larynx. Purpose: To evaluate the results, the safety and effectiveness of patients who were treated with subtotal laryngectomy with epiglottic reconstruction. Material and Method: From January 2012 to July 2017, 42 patients (41 male, 1 female, median age 55.6 years, range 38-75 years) were diagnosed with glottic carcinomas at Vietnam National ENT Hospital, where they underwent a subtotal laryngectomy with epiglottic reconstruction. Results: Thirty-one patients (73.8%) had T2 glottic carcinoma, 4 (9.5%) T3 glottic carcinoma, and 12 (25.6%) had neck dissection. The arytenoid cartilage on the tumor-bearing side was resected in 11 patients (26.2%). Functional ipsilateral neck dissection was performed in 30 patients. Positive lymph node of stage T2 was 1/31 (3.2%). Postoperative histopathologic examination showed a tumour free of resection margin in 41 patients (97.6%). Only one post-operative complication occurred with bleeding 24 hours after surgery. There was no mortality. The 3- and 5-year overall survival rates were 97.6% and 85.7%, respectively. The rate of local control was 92.9%. Conclusion: Subtotal laryngectomy with epiglottic reconstruction was performed mostly for T2 and certain T3 glottic carcinomas when there is difficult to safely remove the tumour with transoral laser microsurgery. This surgery appears to be effective for the overall survival and has potential in clinical practice for treating moderate glottic carcinoma.

Efficacy of the incorporation between self-encapsulation and cryoprotectants on improving the freeze-dried survival of probiotic bacteria.

AIMS: This study aimed to improve the viability of probiotic bacteria during freeze-drying by the combination of self-encapsulation and cryoprotectants. METHODS AND RESULTS: Lactiplantibacillus plantarum VAL6 and Lactobacillus acidophilus VAR1 were exposed to environmental stresses including temperature, pH and increased CO2 concentration before performing freeze-drying with the addition of cryoprotectants. The results proved that tested stresses can stimulate the bacteria to synthesize more extracellular polymeric substances to form self-encapsulation that increases their freeze-dried viability. In combination with cryoprotectants to form double-layered microencapsulation, L. plantarum VAL6 stressed at pH 3.5 in combination with whey protein isolate could achieve the highest Improving Cell Viability of 4361-fold, while L. acidophilus VAR1 stressed at 25o C in combination with alginate gave a maximum Improving Cell Viability of 73.33-fold. CONCLUSIONS: The combination of self-encapsulation and cryoprotectants significantly improves the freeze-dried viability of probiotics. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report that uses environmental stress to stimulate extracellular polymeric substance synthesis for self-encapsulation formation combined with the addition of cryoprotectants to enhance the freeze-dried survival of probiotics. This could be a novel approach in improving the viability of probiotic strains for various applications.

Knowledge, Attitudes and Practices toward Hepatitis B Virus Infection among Students of Medicine in Vietnam.

BACKGROUND: Building capacity in hepatitis B virus prevention and management for medical students and health professionals is one of the pillars of the national viral hepatitis control strategy. METHODS: A cross-sectional study was conducted at eight medical universities from the northern, central and southern regions of the country between May and November 2020 using a systematic random sampling technique. RESULTS: Among 2000 participants, 84.2% reported they had been tested for hepatitis B and 83.9% had received the hepatitis B vaccine. The mean knowledge, attitude, practice score was 40.2 out of 54 (74.4%) with only 19.9% of the study participants obtaining a good score. In multivariate analysis, fifth year students, students from central universities, students who had tested positive for hepatitis B and students who had received hepatitis B vaccine or had encountered patients with chronic hepatitis B had significantly higher knowledge score (p < 0.05). The study showed lack of trust in the hepatitis B vaccine safety and lack of confidence in providing counselling, testing and management of patients with chronic hepatitis B. CONCLUSION: Findings from our research emphasized an immediate need to improve the medical schools' training curriculum in Vietnam to enable students' readiness in hepatitis B prevention and management.

Expression of genes involved in exopolysaccharide synthesis in Lactiplantibacillus plantarum VAL6 under environmental stresses.

Environmental factors can alter exopolysaccharide biosynthesis in lactic acid bacteria (LAB). To further clarify this potential relationship, the mRNA expression of genes involved in exopolysaccharide synthesis such as glmU, pgmB1, cps4E, cps4F, cps4J, and cps4H in Lactiplantibacillus plantarum VAL6 under different conditions including temperature, pH, sodium chloride (NaCl), and carbon dioxide (CO2) intensification culture was studied. The transcriptomic data revealed that the exposure of L. plantarum VAL6 at pH 3 increased the expression level of cps4H but decreased the expression levels of pgmB1 and cps4E. Under pH 8, cps4F and cps4E were significantly upregulated, whereas pgmB1 was downregulated. Similarly, the expression levels of cps4F, cps4E, and cps4J increased sharply under stresses at 42 or 47 °C. In the case of NaCl stress, glmU, pgmB1, cps4J, and cps4H were downregulated in exposure to NaCl at 7 and 10% concentrations while cps4E and cps4F were upregulated at 1 h of 10%-NaCl treatment and at 5 h of 4%-NaCl treatment. Remarkably, CO2 intensification culture stimulated the expression of all tested genes. In addition, simultaneous changes in expression of cps4E and cps4F under environmental challenges may elicit the possibility of an association between the two genes. These findings indicated that the expression level of eps genes is responsible for changes in the yield and monosaccharide composition of exopolysaccharides under environmental stresses.

Health Literacy Toward Zoonotic Diseases Among Livestock Farmers in Vietnam.

BACKGROUND: Zoonoses are an increasing concern worldwide, particularly in low- and middle-income countries. People with close contact with animals are at high risk for contracting and transmitting the zoonotic diseases. OBJECTIVES: To determine health literacy of livestock farmers toward biosecurity to prevent zoonotic diseases. METHODS: This cross-sectional mixed-methods study was conducted in Thai Nguyen Province, Vietnam, where livestock and farming are the main occupation. The questionnaire survey was submitted to 218 farmers who have close contact with livestock. In addition, 8 farmers were invited to an in-depth interview to further explore the health literacy. RESULTS: Half of the participants were men. The average age (standard deviation) of the participants was 49.3(11.5) years. The median years with experience in farming was 15 years. The majority (82.0%) of the participants had moderate health literacy level regarding zoonoses. Improper use of antibiotics was referred by 58.0% of participants, including antibiotic use as feeding supplements (34.0%) and the use of human antibiotics to treat sick animals (24.0%). Many participants were unaware of zoonotic prevention measures and due to this had practices such as not wearing protective equipment (60.0%), an absence of acaricides to prevent vector infestations (52.0%), an absence of disinfection measures (42.0%), low rate of rabies vaccination (54.0%), and do not quarantining sick animals (38.0%). In-depth interviews revealed great concern among farmers about a collective lack of participation from local veterinarians, health workers, and government authorities in zoonoses-prevention efforts. Statistical models showed that farm scale, ethnic groups, and perceived income were associated with the overall health literacy about zoonoses. CONCLUSION: Comprehensive health education related to zoonotic diseases is recommended to improve overall knowledge, including routes of transmission, symptoms and consequences of diseases, and antibiotic usage. In addition, guidance should be provided to farmers on how to treat sick animals, the appropriate use of antibiotics, and waste management. Local veterinarians and health workers are important contact points and should work closely with the farmers to prevent zoonotic diseases.

Urinary 1-hydroxypyrene levels among office workers living in industrial areas.

We examined exposure to polycyclic aromatic hydrocarbons (PAHs) among non-smoking office workers in 2 countries living in the vicinity of a coke-oven factory by measuring their levels of urinary 1-OHP, a known metabolite of PAHs. Subjects included 10 non-smoking office workers in Kitakyushu city (Japan) and 20 workers in Thai Nguyen city (Vietnam). Measurement was optimized by using the high-performance liquid chromatography (HPLC) method developed by Jongeneelen et al. This method required only a small amount of urine and had a short incubation time, and its detection limit was very low (0.00448 ng/ml), which was practical and highly sensitive.The median urinary 1-OHP concentration in the Vietnamese subjects (0.417 ng/mg creatinine) was six times as high as that in the Japanese subjects (0.069 ng/mg creatinine) (P < 0.001). However, both concentrations were significantly below the guideline level, below which there is no genotoxic effect, implying a low probability of any adverse health effects.Our measurements from both countries showed higher urinary 1-OHP concentrations than in previous studies from locations without factories, indicating that ambient air pollution from industrial emissions is an important source of PAH exposure. Finally, the urinary 1-OHP concentrations did not correlate with gender or lifestyle factors.

Urinary 1-hydroxypyrene and 8-hydroxydeoxyguanosine levels among coke-oven workers for 2 consecutive days.

OBJECTIVES: This study evaluated the levels of exposure to polycyclic aromatic hydrocarbons (PAHs) and their relationship with oxidative DNA damage among Vietnamese coke-oven workers. METHODS: We collected urine from 36 coke-oven workers (exposed group) at the beginning and end of the shift on 2 consecutive days. We also collected urine from 78 medical staff (control group). Information was collected by questionnaire about smoking status, drinking habit, and working position. Urinary 1-hydroxypyrene (1-OHP) and 8-hydroxydeoxyguanosine (8-OH-dG) were measured using HPLC. All statistical analyses were performed with SPSS version 19. RESULTS: Urinary 1-OHP was significantly higher in the coke-oven workers than in the control group (p<0.05). Top-oven workers had the highest levels of internal exposure to PAHs, followed by side-oven and then bottom-oven workers (5.41, 4.41 and 1.35 ng/mg creatinine, respectively, at the end of the shift on day 2). Urinary 8-OH-dG was significantly higher in top- and side-oven workers at the end of the shift on day 2 (4.63 and 5.88 ng/mg creatinine, respectively) than in the control group (3.85 ng/mg creatinine). Based on a multi-regression analysis, smoking status had a significant effect on urinary 8-OH-dG (p=0.049). Urinary 1-OHP tended to have a positive correlation with urinary 8-OH-dG (p=0.070). CONCLUSIONS: Vietnamese coke-oven workers were exposed to PAHs during their work shift. Urinary 1-OHP exceeded the recommended limit, and elevated oxidative DNA damage occurred in top- and side-oven workers on the second day of work. A tendency for positive correlation was found between urinary 1-OHP and urinary 8-OH-dG.